WO2024042768A1 - Tire - Google Patents
Tire Download PDFInfo
- Publication number
- WO2024042768A1 WO2024042768A1 PCT/JP2023/014132 JP2023014132W WO2024042768A1 WO 2024042768 A1 WO2024042768 A1 WO 2024042768A1 JP 2023014132 W JP2023014132 W JP 2023014132W WO 2024042768 A1 WO2024042768 A1 WO 2024042768A1
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- WO
- WIPO (PCT)
- Prior art keywords
- tire
- carcass
- point
- range
- tlu
- Prior art date
Links
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Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C13/00—Tyre sidewalls; Protecting, decorating, marking, or the like, thereof
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C3/00—Tyres characterised by the transverse section
- B60C3/04—Tyres characterised by the transverse section characterised by the relative dimensions of the section, e.g. low profile
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C5/00—Inflatable pneumatic tyres or inner tubes
- B60C5/12—Inflatable pneumatic tyres or inner tubes without separate inflatable inserts, e.g. tubeless tyres with transverse section open to the rim
- B60C5/14—Inflatable pneumatic tyres or inner tubes without separate inflatable inserts, e.g. tubeless tyres with transverse section open to the rim with impervious liner or coating on the inner wall of the tyre
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C9/00—Reinforcements or ply arrangement of pneumatic tyres
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C9/00—Reinforcements or ply arrangement of pneumatic tyres
- B60C9/02—Carcasses
- B60C9/04—Carcasses the reinforcing cords of each carcass ply arranged in a substantially parallel relationship
- B60C9/08—Carcasses the reinforcing cords of each carcass ply arranged in a substantially parallel relationship the cords extend transversely from bead to bead, i.e. radial ply
Definitions
- the present invention relates to a tire, and more particularly to a tire that can achieve both tire durability and low rolling resistance.
- An object of the present invention is to provide a tire that can achieve both tire durability and low rolling resistance.
- a tire according to the present invention includes a pair of bead cores, a carcass layer spanning the bead cores, a belt layer disposed on the radially outer side of the carcass layer, and an inner surface of the carcass layer.
- the tire outer diameter OD [mm] is in the range of 200 ⁇ OD ⁇ 660
- the tire total width SW [mm] is in the range of 100 ⁇ SW ⁇ 400
- the tire meridian direction is In the cross-sectional view, define a point Au on the side profile at the same position in the tire radial direction with respect to the end of the innermost layer of the belt layer, and define the foot of the perpendicular line drawn from point Au to the carcass layer as a point.
- the foot of the perpendicular line drawn from the tire maximum width position Ac to the carcass layer is defined as the point Ic, and the carcass layer is made of a single layer or multiple layers of carcass ply consisting of a carcass cord coated with rubber.
- the distance TLu [mm] from the center of the carcass cord of the innermost layer of the carcass ply to the inner surface of the tire in the region from point Iu to point Ic is 0. It is characterized by being in the range of 00010 ⁇ TLu/OD ⁇ 0.01500.
- the tire according to the present invention has the advantage that the distance from the carcass layer to the inner surface of the tire in the region from the end of the belt layer to the tire maximum width position is optimized.
- the above lower limit ensures the distance TLu from the carcass layer to the inner surface of the tire in the above region where air leaks are likely to occur, and suppresses a decrease in tire durability performance and worsening of rolling resistance due to air leaks. Ru.
- the above upper limit suppresses deterioration of rolling resistance due to an increase in tire weight. This achieves both tire durability and low rolling resistance.
- small-diameter tires are used under the above-mentioned high internal pressure and high load, so stress concentration tends to occur easily. Therefore, when the above configuration is adopted for a small diameter tire, the durability performance and low rolling resistance performance of the tire can be significantly improved.
- FIG. 1 is a cross-sectional view in the tire meridian direction showing a tire according to an embodiment of the present invention.
- FIG. 2 is an enlarged view of the tire shown in FIG. 1.
- FIG. 3 is an explanatory diagram showing the laminated structure of the belt layer of the tire shown in FIG.
- FIG. 4 is an enlarged view showing the tread portion of the tire shown in FIG.
- FIG. 5 is an enlarged view showing one side region of the tread portion shown in FIG. 4.
- FIG. FIG. 6 is an enlarged view showing a side fall portion and a bead portion of the tire shown in FIG. 1.
- FIG. 7 is an enlarged view showing the sidewall portion shown in FIG. 6.
- FIG. 8 is an explanatory diagram showing a laminated structure of a carcass layer and a belt layer of the tire shown in FIG. 1.
- FIG. 9 is an explanatory diagram showing a modification of the laminated structure of the carcass layer and belt layer shown in FIG. 8.
- FIG. 10 is an explanatory diagram showing a modification of the laminated structure of the carcass layer and belt layer shown in FIG. 8.
- FIG. 11 is an enlarged view showing the tire radially outer region shown in FIG. 6.
- FIG. FIG. 12 is an explanatory diagram showing a laminated structure of a carcass layer and an inner liner in the radially outer region of the tire shown in FIG. 11.
- FIG. 13 is a chart showing the results of a performance test of the tire according to the embodiment of the present invention.
- FIG. 14 is a chart showing the results of a performance test of the tire according to the embodiment of the present invention.
- FIG. 15 is a chart showing the results of a performance test of the tire according to the embodiment of the present invention
- FIG. 1 is a cross-sectional view in the tire meridian direction showing a tire 1 according to an embodiment of the present invention. This figure shows a cross-sectional view of one side area in the tire radial direction of the tire 1 mounted on the rim 10.
- a pneumatic radial tire for a passenger car will be described as an example of a tire.
- a cross section in the tire meridian direction is defined as a cross section when the tire is cut along a plane that includes the tire rotation axis (not shown).
- the tire equatorial plane CL is defined as a plane that passes through the midpoint of the tire cross-sectional width DW defined in JATMA and is perpendicular to the tire rotation axis.
- the tire width direction is defined as a direction parallel to the tire rotation axis
- the tire radial direction is defined as a direction perpendicular to the tire rotation axis.
- point T is the tire ground contact edge
- point Ac is the tire maximum width position.
- the tire 1 has an annular structure centered around the tire rotation axis, and includes a pair of bead cores 11, 11, a pair of bead fillers 12, 12, a carcass layer 13, a belt layer 14, a tread rubber 15, and a pair of bead cores 11, 11, a pair of bead fillers 12, 12, a carcass layer 13, a belt layer 14, a tread rubber 15, sidewall rubber 16, 16, a pair of rim cushion rubber 17, 17, and an inner liner 18 (see FIG. 1).
- the pair of bead cores 11, 11 are formed by winding one or more bead wires made of steel in an annular shape and multiple times, and are embedded in the bead portions to form the cores of the left and right bead portions.
- the pair of bead fillers 12, 12 are arranged on the outer peripheries of the pair of bead cores 11, 11 in the tire radial direction, respectively, to reinforce the bead portions.
- the bead filler 12 has a rubber hardness Hs_bf of 55 or more and 105 or less, a modulus at 100 [%] elongation M_bf [MPa] of 2.0 or more and 13.0 or less, and a loss tangent of 0.03 or more and 0.30 or less.
- tan ⁇ _bf preferably a rubber hardness Hs_bf of 70 or more and 100 or less, a modulus M_bf [MPa] at elongation of 100 [%] of 3.0 or more and 12.0 or less, and a loss tangent of 0.05 or more and 0.25 or less. It has tan ⁇ _bf.
- the carcass layer 13 has a single layer structure consisting of one carcass ply or a multilayer structure consisting of a plurality of carcass plies laminated, and is spanned in a toroidal shape between the left and right bead cores 11, 11, and is the frame of the tire. Configure. Further, both ends of the carcass layer 13 are wound back and locked outward in the tire width direction so as to wrap around the bead core 11 and bead filler 12. Further, the carcass ply of the carcass layer 13 is formed by covering a plurality of carcass cords made of inorganic fibers (e.g., steel, carbon fiber, glass fiber) or organic fibers (e.g., aramid, nylon, polyester, rayon, etc.) with coated rubber.
- the cord angle (defined as the inclination angle in the longitudinal direction of the carcass cord with respect to the tire circumferential direction) is 80 [deg] or more and 100 [deg] or less.
- the belt layer 14 is formed by laminating a plurality of belt plies 141 to 144, and is arranged to be wrapped around the outer periphery of the carcass layer 13.
- belt plies 141 to 144 are composed of a pair of intersecting belts 141, 142, a belt cover 143, and a pair of belt edge covers 144, 144.
- the pair of crossed belts 141 and 142 are constructed by rolling a plurality of belt cords made of steel or organic fibers coated with rubber, and have a cord angle of 15 [deg] or more and 55 [deg] or less in absolute value ( ) is defined as the inclination angle of the belt cord in the longitudinal direction with respect to the tire circumferential direction. Further, the pair of crossed belts 141 and 142 have cord angles of opposite signs and are laminated with the longitudinal directions of the belt cords crossing each other (so-called cross-ply structure). Further, the pair of crossing belts 141 and 142 are stacked and arranged on the outside of the carcass layer 13 in the tire radial direction.
- the belt cover 143 and the pair of belt edge covers 144, 144 are constructed by covering a belt cover cord made of steel or organic fiber material with coated rubber, and have a cord angle of 0 [deg] or more and 10 [deg] or less in absolute value.
- the belt cover 143 and the belt edge cover 144 are, for example, strip materials made by covering one or more belt cover cords with coated rubber, and these strip materials are applied to the outer peripheral surfaces of the crossed belts 141 and 142. It is constructed by wrapping it spirally multiple times in the circumferential direction of the tire.
- a belt cover 143 is arranged to cover the entire area of the crossing belts 141, 142, and a pair of belt edge covers 144, 144 are arranged to cover the left and right edge portions of the crossing belts 141, 142 from the outside in the tire radial direction.
- the tread rubber 15 is arranged on the outer periphery of the carcass layer 13 and the belt layer 14 in the tire radial direction, and constitutes the tread portion of the tire 1. Further, the tread rubber 15 includes a cap tread 151 and an undertread 152.
- the cap tread 151 is made of a rubber material with excellent ground contact characteristics and weather resistance, and is exposed on the tread surface over the entire tire contact area and constitutes the outer surface of the tread portion.
- the cap tread 151 has a rubber hardness Hs_cap of 50 or more and 80 or less, a modulus M_cap [MPa] at 100 [%] elongation of 1.0 or more and 4.0 or less, and a loss tangent of 0.03 or more and 0.36 or less.
- tan ⁇ _cap preferably rubber hardness Hs_cap of 58 or more and 76 or less, modulus at 100 [%] elongation M_cap [MPa] of 1.5 or more and 3.2 or less, and loss tangent of 0.06 or more and 0.29 or less. It has tan ⁇ _cap.
- Rubber hardness Hs is measured at a temperature of 20 [° C.] in accordance with JIS K6253.
- the modulus (breaking strength) is measured by a tensile test at a temperature of 20 [° C.] using a dumbbell-shaped test piece in accordance with JIS K6251 (using a No. 3 dumbbell).
- the loss tangent tan ⁇ was determined using a viscoelastic spectrometer manufactured by Toyo Seiki Seisakusho Co., Ltd. under the conditions of temperature 60 [°C], shear strain 10 [%], amplitude ⁇ 0.5 [%], and frequency 20 [Hz]. It is measured in
- the undertread 152 is made of a rubber material with excellent heat resistance, is sandwiched between the cap tread 151 and the belt layer 14, and forms the base portion of the tread rubber 15.
- the undertread 152 has a rubber hardness Hs_ut of 47 or more and 80 or less, a modulus at 100 [%] elongation M_ut [MPa] of 1.4 or more and 5.5 or less, and a loss tangent of 0.02 or more and 0.23 or less.
- tan ⁇ _ut preferably a rubber hardness Hs_ut of 50 or more and 65 or less, a modulus at 100 [%] elongation M_ut [MPa] of 1.7 or more and 3.5 or less, and a loss tangent of 0.03 or more and 0.10 or less. It has tan ⁇ _ut.
- the difference in rubber hardness Hs_cap ⁇ Hs_ut is in the range of 3 or more and 20 or less, preferably in the range of 5 or more and 15 or less.
- the modulus difference M_cap ⁇ M_ut [MPa] is in the range of 0 or more and 1.4 or less, preferably 0.1 or more and 1.0 or less.
- the loss tangent difference tan ⁇ _cap ⁇ tan ⁇ _ut is in the range of 0 or more and 0.22 or less, preferably 0.02 or more and 0.16 or less.
- a pair of sidewall rubbers 16, 16 are respectively arranged on the outside of the carcass layer 13 in the tire width direction, and constitute left and right sidewall portions.
- the outer end of the sidewall rubber 16 in the tire radial direction is disposed below the tread rubber 15 and is sandwiched between the end of the belt layer 14 and the carcass layer 13.
- the present invention is not limited thereto, and the outer end of the sidewall rubber 16 in the tire radial direction may be disposed on the outer layer of the tread rubber 15 and exposed to the buttress portion of the tire (not shown). In this case, a belt cushion (not shown) is sandwiched between the end of the belt layer 14 and the carcass layer 13.
- the sidewall rubber 16 has a rubber hardness Hs_sw of 48 or more and 65 or less, a modulus M_sw [MPa] at 100 [%] elongation of 1.0 or more and 2.4 or less, and a loss of 0.02 or more and 0.22 or less. It has a tangent tan ⁇ _sw, preferably a rubber hardness Hs_sw of 50 or more and 59 or less, a modulus M_sw [MPa] at 100 [%] elongation of 1.2 or more and 2.2 or less, and a loss of 0.04 or more and 0.20 or less. It has a tangent tan ⁇ _sw.
- a pair of rim cushion rubbers 17, 17 extend from the inner side in the tire radial direction to the outer side in the tire width direction of the left and right bead cores 11, 11 and the rolled-up portion of the carcass layer 13, and constitute a rim fitting surface of the bead portion.
- the outer end of the rim cushion rubber 17 in the tire radial direction is inserted into the lower layer of the sidewall rubber 16, and is sandwiched between the sidewall rubber 16 and the carcass layer 13. .
- the rim cushion rubber 17 has a rubber hardness Hs_rc of 60 or more and 80 or less, a modulus M_rc [MPa] at 100 [%] elongation of 2.0 or more and 7.0 or less, and a loss of 0.09 or more and 0.35 or less. It has a tangent tan ⁇ _rc, preferably a rubber hardness Hs_rc of 65 or more and 75 or less, a modulus M_rc [MPa] at 100 [%] elongation of 3.0 or more and 6.0 or less, and a loss of 0.11 or more and 0.30 or less. It has a tangent tan ⁇ _rc.
- the inner liner 18 is an air permeation prevention layer placed on the inner cavity surface of the tire and covering the carcass layer 13, and suppresses oxidation due to exposure of the carcass layer 13, and also prevents air filled in the tire from leaking.
- the inner liner 18 may be made of, for example, a rubber composition containing butyl rubber as a main component, or may be made of a thermoplastic resin or a thermoplastic elastomer composition obtained by blending an elastomer component into a thermoplastic resin. Also good.
- the tire outer diameter OD [mm] is in the range of 200 ⁇ OD ⁇ 660, preferably in the range of 250 [mm] ⁇ OD ⁇ 580 [mm].
- the tire total width SW [mm] is in the range of 100 ⁇ SW ⁇ 400, preferably in the range of 105 [mm] ⁇ SW ⁇ 340 [mm].
- the tire outer diameter OD is measured while the tire is mounted on a specified rim, a specified internal pressure is applied, and the tire is in an unloaded state.
- Tire total width SW is measured as the straight line distance between the sidewalls (including all parts such as the pattern on the side of the tire, letters, etc.) when the tire is mounted on the specified rim, the specified internal pressure is applied, and no load is applied. be done.
- the specified rim refers to the "applicable rim” specified in JATMA, the "Design Rim” specified in TRA, or the “Measuring Rim” specified in ETRTO.
- the specified internal pressure refers to the "maximum air pressure” specified in JATMA, the maximum value of "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” specified in TRA, or “INFLATION PRESSURES” specified in ETRTO.
- the specified load refers to the "maximum load capacity" specified in JATMA, the maximum value of "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" specified in TRA, or "LOAD CAPACITY” specified in ETRTO.
- the specified internal pressure is 180 [kPa]
- the specified load is 88 [%] of the maximum load capacity.
- the total tire width SW [mm] is in the range of 0.23 ⁇ SW/OD ⁇ 0.84 with respect to the tire outer diameter OD [mm], preferably 0.25 ⁇ SW/OD ⁇ 0.81. within the range of
- the tire outer diameter OD and the tire total width SW satisfy the following formula (1).
- a rim 10 having a rim diameter of 5 [inch] or more and 16 [inch] or less that is, 125 [mm] or more and 407 [mm] or less
- the rim diameter RD [mm] is in the range of 0.50 ⁇ RD/OD ⁇ 0.74 with respect to the tire outer diameter OD [mm], preferably 0.52 ⁇ RD/OD ⁇ 0.71. in range.
- the rim diameter RD can be secured, and especially the installation space for the in-wheel motor can be secured.
- the inner volume V of the tire which will be described later, is ensured, and the load capacity of the tire is ensured.
- the tire inner diameter is equal to the rim diameter RD of the rim 10.
- the tire 1 is expected to be used at an internal pressure higher than the regulation, specifically at an internal pressure of 350 [kPa] or more and 1200 [kPa] or less, preferably 500 [kPa] or more and 1000 [kPa] or less.
- the lower limit effectively reduces the rolling resistance of the tire, and the upper limit ensures the safety of the internal pressure filling operation.
- the tire 1 is mounted on a vehicle that travels at low speed, such as a small shuttle bus, for example. Further, the maximum speed of the vehicle is 100 [km/h] or less, preferably 80 [km/h] or less, and more preferably 60 [km/h] or less. Further, it is assumed that the tire 1 is mounted on a vehicle with 6 to 12 wheels. Thereby, the load capacity of the tire is properly exhibited.
- the aspect ratio of the tire that is, the ratio SH/DW of the tire cross-sectional height SH [mm] (see FIG. 2 described later) and the tire cross-sectional width DW [mm] is 0.16 ⁇ SH/DW ⁇ 0.85. It is preferably in the range of 0.19 ⁇ SH/DW ⁇ 0.82.
- the tire cross-sectional height SH is a distance that is 1/2 of the difference between the tire outer diameter and the rim diameter, and is measured with the tire mounted on a specified rim, a specified internal pressure applied, and an unloaded state.
- the tire cross-sectional width DW is measured as the straight-line distance between the sidewalls (excluding patterns, letters, etc. on the side surface of the tire) when the tire is mounted on a specified rim, a specified internal pressure is applied, and the tire is in an unloaded state.
- the tire ground contact width TW is in the range of 0.50 ⁇ TW/SW ⁇ 0.85 with respect to the tire total width SW, preferably in the range of 0.60 ⁇ TW/SW ⁇ 0.80.
- Tire contact width TW is the contact surface between the tire and the flat plate when the tire is mounted on a specified rim, a specified internal pressure is applied, and the tire is placed perpendicular to the flat plate in a stationary state and a load corresponding to the specified load is applied. measured as the maximum straight line distance in the axial direction of the tire.
- the tire internal volume V [m ⁇ 3] is in the range of 4.0 ⁇ (V/OD) ⁇ 10 ⁇ 6 ⁇ 60 with respect to the tire outer diameter OD [mm], preferably 6.0 ⁇ ( V/OD) ⁇ 10 ⁇ 6 ⁇ 50.
- the tire internal volume V is optimized.
- the above lower limit ensures the inner volume of the tire and the load capacity of the tire.
- small-diameter tires are expected to be used under high internal pressure and high load, so it is preferable that the tire internal volume V is sufficiently secured.
- the above upper limit suppresses the tire from increasing in size due to the tire internal volume V becoming excessively large.
- the tire internal volume V [m ⁇ 3] is in the range of 0.5 ⁇ V ⁇ RD ⁇ 17 with respect to the rim diameter RD [mm], preferably in the range of 1.0 ⁇ V ⁇ RD ⁇ 15. be.
- a pair of bead cores 11, 11 are formed by winding one or more bead wires (not shown) made of steel in an annular manner and in multiple layers. Further, a pair of bead fillers 12, 12 are arranged on the outer peripheries of the pair of bead cores 11, 11 in the tire radial direction, respectively.
- the strength Tbd [N] of one bead core 11 is in the range of 45 ⁇ Tbd/OD ⁇ 120 with respect to the tire outer diameter OD [mm], preferably in the range of 50 ⁇ Tbd/OD ⁇ 110, More preferably, the range is 60 ⁇ Tbd/OD ⁇ 105. Further, the strength Tbd [N] of the bead core is in the range of 90 ⁇ Tbd/SW ⁇ 400, preferably in the range of 110 ⁇ Tbd/SW ⁇ 350 with respect to the tire total width SW [mm]. Thereby, the load capacity of the bead core 11 is appropriately ensured. Specifically, the above lower limit suppresses tire deformation during use under high loads and ensures tire durability.
- the tire it becomes possible to use the tire at high internal pressure, and the rolling resistance of the tire is reduced.
- small-diameter tires are expected to be used under high internal pressure and high loads, so the above-described tire durability and rolling resistance reduction effect can be significantly achieved.
- the above upper limit suppresses deterioration of rolling resistance due to an increase in the mass of the bead core.
- the strength Tbd [N] of the bead core 11 is calculated as the product of the strength per bead wire [N/piece] and the total number of bead wires [pieces] in a radial cross-sectional view.
- the strength of the bead wire is measured by a tensile test at a temperature of 20 [° C.] in accordance with JIS K1017.
- the strength Tbd [N] of the bead core 11 satisfies the following formula (2) with respect to the tire outer diameter OD [mm], the distance SWD [mm], and the rim diameter RD [mm].
- the distance SWD is twice the radial distance from the tire rotation axis (not shown) to the tire maximum width position Ac, that is, the diameter of the tire maximum width position Ac. It is measured as an unloaded state when applied.
- the tire maximum width position Ac is defined as the maximum width position of the tire cross-sectional width DW specified by JATMA.
- the total cross-sectional area ⁇ bd [mm ⁇ 2] of the bead wire made of steel described above is 0.025 ⁇ bd/OD ⁇ with respect to the tire outer diameter OD [mm]. It is in the range of 0.075, preferably in the range of 0.030 ⁇ bd/OD ⁇ 0.065. Further, the total cross-sectional area ⁇ bd [mm ⁇ 2] of the bead wire is in the range of 11 ⁇ bd ⁇ 36, preferably in the range of 13 ⁇ bd ⁇ 33. Thereby, the strong Tbd[N] of the bead core 11 described above is realized.
- the total cross-sectional area ⁇ bd [mm ⁇ 2] of the bead wire is calculated as the sum of the cross-sectional areas of the bead wire in a radial cross-sectional view of one bead core 11.
- the bead core 11 has a rectangular shape formed by arranging bead wires (not shown) having a circular cross section in a grid pattern.
- the present invention is not limited to this, and the bead core 11 may have a hexagonal shape formed by arranging bead wires having a circular cross section in a close-packed structure (not shown).
- any bead wire arrangement structure can be adopted within the range obvious to those skilled in the art.
- the total cross-sectional area ⁇ bd [mm ⁇ 2] of the bead wire satisfies the following formula (3) with respect to the tire outer diameter OD [mm], the distance SWD [mm], and the rim diameter RD [mm].
- the total cross-sectional area ⁇ bd [mm ⁇ 2] of the bead wire is 0.50 ⁇ bd/Nbd with respect to the total number of cross-sections (that is, the total number of turns) Nbd [pieces] of the bead wire of one bead core 11 in a radial cross-sectional view. It is in the range of ⁇ 1.40, preferably in the range of 0.60 ⁇ bd/Nbd ⁇ 1.20. That is, the cross-sectional area ⁇ bd' [mm ⁇ 2] of a single bead wire is in the range of 0.50 [mm ⁇ 2/piece] to 1.40 [mm ⁇ 2/piece], preferably 0.60 [mm ⁇ 2/piece]. mm ⁇ 2/piece] or more and 1.20 [mm ⁇ 2/piece] or less.
- the maximum width Wbd [mm] of one bead core 11 in a radial cross-sectional view is 0.16 ⁇ Wbd/ ⁇ bd ⁇ 0 with respect to the total cross-sectional area ⁇ bd [mm ⁇ 2] of the bead wire. .50, preferably 0.20 ⁇ Wbd/ ⁇ bd ⁇ 0.40.
- the distance Dbd [mm] between the centers of gravity of the pair of bead cores 11, 11 is preferably in the range of 0.63 ⁇ Dbd/SW ⁇ 0.97 with respect to the tire total width SW [mm]. is in the range of 0.65 ⁇ Dbd/SW ⁇ 0.95.
- the radial distance BH [mm] from the radially outer end of the bead core 11 to the radially outer end of the bead filler 23, that is, the height of the bead filler 23 is equal to the tire cross-sectional height SH [mm] is in the range of 0.10 ⁇ BH/SH ⁇ 0.40, preferably in the range of 0.15 ⁇ BH/SH ⁇ 0.35.
- the radial distance BH [mm] is measured with the tire mounted on a specified rim, a specified internal pressure applied, and an unloaded state.
- FIG. 2 is an enlarged view showing the tire 1 shown in FIG. The figure shows a region on one side with the tire equatorial plane CL as a boundary.
- the carcass layer 13 is composed of a single layer of carcass ply, and is arranged in a toroidal manner between the left and right bead cores 11, 11. Further, both ends of the carcass layer 13 are rolled back and locked outward in the tire width direction so as to wrap around the bead core 11 and bead filler 12.
- the strength Tcs [N/50mm] per width 50 [mm] of the carcass ply constituting the carcass layer 13 is preferably in the range of 17 ⁇ Tcs/OD ⁇ 120 with respect to the tire outer diameter OD [mm]. is in the range of 20 ⁇ Tcs/OD ⁇ 120. Further, the strength Tcs [N/50mm] of the carcass layer 13 is in the range of 30 ⁇ Tcs/SW ⁇ 260 with respect to the tire total width SW [mm], preferably in the range of 35 ⁇ Tcs/SW ⁇ 220. . In such a configuration, since the load capacity of the carcass layer 13 is appropriately ensured in a small-diameter tire, there is an advantage that the tire has both durability performance and low rolling resistance performance.
- the above lower limit suppresses tire deformation during use under high loads and ensures tire durability.
- small-diameter tires are expected to be used under high internal pressure and high loads, so the above-described tire durability and rolling resistance reduction effect can be significantly achieved.
- the above upper limit suppresses deterioration of rolling resistance due to increase in mass of the carcass layer.
- the strength Tcs [N/50mm] of the carcass ply is calculated as follows. That is, the carcass ply that spans the left and right bead cores 11 and extends over the entire inner circumference of the tire is defined as an effective carcass ply. Then, the strength per carcass cord [N/piece] that constitutes an effective carcass ply and the number of carcass cords driven per width 50 [mm] around the entire circumference of the tire and on the tire equatorial plane CL [pieces/50mm] The product is calculated as the carcass ply strength Tcs [N/50mm]. The strength of the carcass cord is measured by a tensile test at a temperature of 20 [° C.] in accordance with JIS K1017.
- the strength of one twisted carcass cord is measured, and the strength Tcs of the carcass layer 13 is calculated.
- the above-mentioned strength Tcs is defined for each of the plurality of effective carcass plies.
- the carcass layer 13 has a single layer structure consisting of a single carcass ply (number omitted in the figure), and the carcass ply has a carcass cord made of steel covered with coated rubber.
- the cords are arranged at a cord angle of 80 [deg] or more and 100 [deg] or less with respect to the tire circumferential direction (not shown).
- the carcass cord made of steel described above has a cord diameter ⁇ cs [mm] in a range of 0.15 ⁇ cs ⁇ 1.10, preferably in a range of 0.25 ⁇ cs ⁇ 0.60, and a cord diameter ⁇ cs [mm] in a range of 25 ⁇ Ecs ⁇ 80.
- the carcass cord is formed by twisting a plurality of wires, and the wire diameter ⁇ css [mm] is in the range of 0.12 ⁇ css ⁇ 0.24, preferably 0.14 ⁇ css ⁇ 0. It is in the range of 22. Further, it is more preferable that the wire diameter ⁇ css [mm] of the carcass cord is in the range of 0.30 ⁇ css/ ⁇ cs ⁇ 0.90 with respect to the cord diameter ⁇ cs [mm] of the carcass cord.
- the carcass cord may be made of inorganic fibers other than steel (eg, carbon fiber, glass fiber, etc.).
- the present invention is not limited to the above, and the carcass ply may be constituted by a carcass cord made of an organic fiber material (for example, aramid, nylon, polyester, rayon, etc.) coated with coated rubber.
- the carcass cord made of the above-mentioned organic fiber material has a cord diameter ⁇ cs [mm] in the range of 0.60 ⁇ cs ⁇ 0.90 and a driving number Ecs [pieces/cord] in the range 40 ⁇ Ecs ⁇ 70. 50 mm], the above-described strong Tcs of the carcass layer 13 [N/50 mm] is realized.
- carcass cords made of high-strength organic fiber materials such as nylon, aramid, and hybrid can be employed within the range obvious to those skilled in the art.
- the carcass layer 13 may have a multilayer structure formed by laminating a plurality of carcass plies, for example, two layers (not shown). Thereby, the load capacity of the tire can be effectively increased.
- the total strength TTcs [N] of the carcass layer 13 is in the range of 300 ⁇ TTcs/OD ⁇ 3500, preferably in the range of 400 ⁇ TTcs/OD ⁇ 3000 with respect to the tire outer diameter OD [mm]. This ensures the entire load capacity of the carcass layer 13.
- the total strength TTcs [N] of the carcass layer 13 is calculated as the product of the strength per carcass cord [N/cord] and the total number of carcass cords driven into the entire carcass layer 13 [number]. Therefore, the total strength TTcs [N] of the carcass layer 13 increases as the strength Tcs [N/50 mm] of each carcass ply, the number of laminated carcass plies, the circumference of the carcass ply, etc. increase.
- the total strength TTcs [N] of the carcass layer 13 satisfies the following formula (4) with respect to the tire outer diameter OD [mm] and the distance SWD [mm].
- Dmin 0.02 ⁇ P using the specified tire internal pressure P [kPa].
- the carcass layer 13 includes a main body portion 131 extending along the inner surface of the tire, and a rolled-up portion extending in the tire radial direction that is rolled up outward in the tire width direction so as to wrap around the bead core 11.
- the radial height Hcs [mm] from the measurement point of the rim diameter RD to the end of the rolled-up portion 132 of the carcass layer 13 is 0.10 ⁇ with respect to the tire cross-sectional height SH [mm].
- the radial height Hcs [mm] of the rolled-up portion 132 of the carcass layer 13 is measured with the tire mounted on a specified rim, a specified internal pressure applied, and an unloaded state.
- the radially outer end (number omitted in the figure) of the rolled-up portion 132 of the carcass layer 13 is located in a region radially inward of the tire maximum width position Ac. is within the range from the tire maximum width position Ac to a radial position Al' that is 70% of the distance Hl, which will be described later.
- the contact height Hcs' [mm] between the main body part 131 and the rolled-up part 132 of the carcass layer 13 is in the range of 0.07 ⁇ Hcs'/SH with respect to the tire cross-sectional height SH [mm], It is preferably in the range of 0.10 ⁇ Hcs'/SH. This effectively increases the load capacity of the tire side portion.
- the upper limit of the ratio Hcs'/SH is not particularly limited, but is limited by the fact that the contact height Hcs' has a relationship of Hcs' ⁇ Hcs with respect to the radial height Hcs of the rolled up portion 132 of the carcass layer 13. .
- the contact height Hcs' of the carcass layer 13 is the extension length in the tire radial direction of the region where the main body part 131 and the rolled-up part 132 contact each other, and when the tire is mounted on a specified rim and a specified internal pressure is applied. and is measured as a no-load condition.
- FIG. 3 is an explanatory diagram showing the laminated structure of the belt layers of the tire 1 shown in FIG. 1.
- thin lines attached to each belt ply 141 to 144 schematically show the arrangement of the belt cords.
- the belt layer 14 is formed by laminating a plurality of belt plies 141 to 144. Further, as shown in FIG. 3, these belt plies 141 to 144 are composed of a pair of crossed belts 141, 142, a belt cover 143, and a pair of belt edge covers 144, 144.
- the strength Tbt [N/50 mm] per width 50 [mm] of each of the pair of crossed belts 141 and 142 is in the range of 25 ⁇ Tbt/OD ⁇ 250 with respect to the tire outer diameter OD [mm]. , preferably in the range of 30 ⁇ Tbt/OD ⁇ 230. Further, the strength Tbt [N/50mm] of the crossing belts 141 and 142 is in the range of 45 ⁇ Tbt/SW ⁇ 500 with respect to the tire total width SW [mm], preferably in the range of 50 ⁇ Tbt/SW ⁇ 450. It is in. Thereby, the load capacity of each of the pair of crossing belts 141 and 142 is appropriately ensured.
- the above lower limit suppresses tire deformation during use under high loads and ensures tire durability.
- small-diameter tires are expected to be used under high internal pressure and high loads, so the above-described tire durability and rolling resistance reduction effect can be significantly achieved.
- the above upper limit suppresses deterioration of rolling resistance due to an increase in the mass of the intersecting belt.
- the strength Tbt [N/50mm] of the belt ply is calculated as follows. That is, the belt ply extending over the entire area of 80% of the tire ground contact width TW centered on the tire equatorial plane CL (that is, the central part of the tire ground contact area) is defined as an effective belt ply. Then, the strength [N/piece] per belt cord constituting the effective belt ply and the number of belt cords driven per width 50 [mm] in the area of 80 [%] of the tire ground contact width TW described above [pieces] The product is calculated as the belt ply strength Tbt [N/50mm].
- the strength of the belt cord is measured by a tensile test at a temperature of 20 [° C.] in accordance with JIS K1017. For example, in a configuration in which one belt cord is formed by twisting a plurality of wires together, the strength of the one twisted belt cord is measured, and the strength Tbt of the belt ply is calculated. Further, in a structure in which the belt layer 14 is formed by laminating a plurality of effective belt plies (see FIG. 1), the above-mentioned strength Tbt is defined for each of the plurality of effective belt plies. For example, in the configuration of FIG. 1, a pair of intersecting belts 141 and 142 and a belt cover 143 correspond to the effective belt ply.
- a pair of crossed belts 141 and 142 extend a steel belt cord covered with coated rubber at a cord angle of 15 degrees or more and 55 degrees or less (in the figure) with respect to the tire circumferential direction. (dimension symbol omitted).
- the above-mentioned steel belt cord has a cord diameter ⁇ bt [mm] in the range of 0.50 ⁇ bt ⁇ 1.80 and a number of inserted cords Ebt [pieces/50 mm] in the range of 15 ⁇ Ebt ⁇ 75.
- a strong Tbt [N/50 mm] of the crossing belts 141 and 142 is realized.
- the cord diameter ⁇ bt [mm] and the driving number Ebt [pieces/50 mm] are preferably in the ranges of 0.55 ⁇ bt ⁇ 1.60 and 17 ⁇ Ebt ⁇ 50, and 0.60 ⁇ bt ⁇ 1. It is more preferable to be in the range of 30 and 20 ⁇ Ebt ⁇ 40.
- the belt cord is formed by twisting a plurality of wires, and the wire diameter ⁇ bts [mm] is in the range of 0.16 ⁇ bts ⁇ 0.43, preferably 0.21 ⁇ bts ⁇ 0. It is in the range of 39.
- the crossed belts 141 and 142 may be constituted by belt cords made of an organic fiber material (for example, aramid, nylon, polyester, rayon, etc.) coated with coated rubber.
- the belt cord made of the organic fiber material has a cord diameter ⁇ bt [mm] in the range of 0.50 ⁇ bt ⁇ 0.90 and a number of cords Ebt [cords/cord] in the range 30 ⁇ Ebt ⁇ 65. 50 mm], the above-mentioned strong force Tbt [N/50 mm] of the crossing belts 141 and 142 is realized.
- a belt cord made of a highly strong organic fiber material such as nylon, aramid, or hybrid can be employed within the range obvious to those skilled in the art.
- the belt layer 14 may include an additional belt (not shown).
- an additional belt is, for example, (1) a third cross belt, which is constructed by covering a plurality of belt cords made of steel or organic fiber material with coated rubber and rolling them, and has an absolute value of 15 [deg] or more. It has a cord angle of 55[deg] or less, or (2) it is a so-called high-angle belt, which is constructed by rolling a plurality of belt cords made of steel or organic fiber material and coated with rubber, and the absolute value The cord angle may be 45 [deg] or more and 70 [deg] or less, preferably 54 [deg] or more and 68 [deg] or less.
- the additional belt is located between (a) the pair of crossed belts 141, 142 and the carcass layer 13, (b) between the pair of crossed belts 141, 142, or (c) between the pair of crossed belts 141, 142. It may be arranged radially outward (not shown). This improves the load capacity of the belt layer 14.
- the total strength TTbt [N] of the belt layer 14 is in the range of 70 ⁇ TTbt/OD ⁇ 750 with respect to the tire outer diameter OD [mm], preferably in the range of 90 ⁇ TTbt/OD ⁇ 690, More preferably, the range is 110 ⁇ TTbt/OD ⁇ 690, and even more preferably, the range is 120 ⁇ TTbt/OD ⁇ 690. This ensures the entire load capacity of the belt layer 14. Furthermore, using the specified internal pressure P [kPa] of the tire, it is preferable that 0.16 ⁇ P ⁇ TTbt/OD.
- the total strength TTbt [N] of the belt layer 14 is calculated as the product of the strength per belt cord [N/cord] and the total number of belt cords driven in the entire belt layer 14 [number]. Therefore, the total strength TTbt [N] of the belt layer 14 increases as the strength Tbt [N/50 mm] of each belt ply, the number of laminated belt plies, etc. increase.
- the width Wb1 [of the widest intersecting belt (in FIG. 3, the intersecting belt 141 on the inner diameter side) of the pair of intersecting belts 141 and 142 (the above-mentioned configuration includes the additional belt; not shown) mm] is in the range of 1.00 ⁇ Wb1/Wb2 ⁇ 1.40 with respect to the width Wb2 [mm] of the narrowest cross belt (in FIG. 3, the cross belt 142 on the outer diameter side), and preferably It is in the range of 1.10 ⁇ Wb1/Wb2 ⁇ 1.35.
- the width Wb2 [mm] of the narrowest crossing belt is in the range of 0.61 ⁇ Wb2/SW ⁇ 0.96 with respect to the total tire width SW [mm], preferably 0.70 ⁇ Wb2/ SW is in the range of 0.94.
- the width of the belt ply is ensured, the ground contact pressure distribution in the tire ground contact area is optimized, and the uneven wear resistance of the tire is ensured.
- the above upper limit reduces distortion at the end of the belt ply during tire rolling, and suppresses separation of rubber around the end of the belt ply.
- the width of the belt ply is the distance between the left and right ends of each belt ply in the direction of the tire rotation axis, and is measured with the tire mounted on a specified rim, a specified internal pressure applied, and an unloaded state.
- the width Wb1 [of the widest intersecting belt (in FIG. 3, the intersecting belt 141 on the inner diameter side) of the pair of intersecting belts 141 and 142 (the above-mentioned configuration includes the additional belt; not shown) mm] is in the range of 0.85 ⁇ Wb1/TW ⁇ 1.23 with respect to the tire ground contact width TW [mm], preferably in the range of 0.90 ⁇ Wb1/TW ⁇ 1.20.
- a wide cross belt 141 is arranged at the innermost layer in the radial direction of the tire, and a narrow cross belt 142 is arranged on the outer side in the radial direction of the wide cross belt 141.
- the belt cover 143 is disposed on the radially outer side of the narrow cross belt 142 and covers both of the pair of cross belts 141 and 142 in their entirety.
- a pair of belt edge covers 144, 144 are arranged radially outward of the belt cover 143 while being spaced apart from each other, and cover the left and right edge portions of the pair of intersecting belts 141, 142, respectively.
- FIG. 4 is an enlarged view showing the tread portion of the tire 1 shown in FIG.
- the depression amount DA [mm] of the tread profile at the tire ground contact edge T, the tire ground contact width TW [mm], and the tire outer diameter OD [mm] are 0.015 ⁇ TW/(DA ⁇ OD) ⁇ 0. 300, preferably 0.020 ⁇ TW/(DA ⁇ OD) ⁇ 0.250.
- the depression amount DA [mm] of the tread profile at the tire ground contact edge T has a relationship of 0.01 ⁇ DA/TW ⁇ 0.10 with respect to the tire ground contact width TW [mm], preferably 0.02 The relationship is ⁇ DA/TW ⁇ 0.08.
- the depression angle (defined by the ratio DA/(TW/2)) of the shoulder region of the tread portion is optimized, and the load capacity of the tread portion is appropriately ensured.
- the depression angle of the tread shoulder region is ensured, and a reduction in wear life due to excessive ground pressure in the tread shoulder region is suppressed.
- the tire ground contact area becomes flat, the ground contact pressure becomes uniform, and the wear resistance performance of the tire is ensured.
- small-diameter tires are expected to be used under high internal pressure and high load, so the above configuration can effectively optimize the ground pressure distribution in the tire ground contact area.
- the depression amount DA is the distance in the tire radial direction from the intersection C1 of the tire equatorial plane CL and the tread profile to the tire ground contact edge T in a cross-sectional view in the tire meridian direction, and the tire is mounted on a specified rim and a specified internal pressure is applied. It is also measured as a no-load condition.
- the tire profile is the outline of the tire in a cross-sectional view in the tire meridian direction, and is measured using a laser profiler.
- a laser profiler for example, a tire profile measuring device (manufactured by Matsuo Co., Ltd.) is used.
- the depression amount DA [mm] of the tread profile at the tire ground contact edge T satisfies the following formula (5) with respect to the tire outer diameter OD [mm] and the tire total width SW [mm].
- a point C1 on the tread profile at the tire equatorial plane CL and a pair of points C2, C2 on the tread profile at a distance of 1/4 of the tire ground contact width TW from the tire equatorial plane CL are defined.
- the radius of curvature TRc [mm] of the circular arc passing through the point C1 and the pair of points C2 is in the range of 0.15 ⁇ TRc/OD ⁇ 15 with respect to the tire outer diameter OD [mm], preferably 0.15 ⁇ TRc/OD ⁇ 15. It is in the range of 18 ⁇ TRc/OD ⁇ 12. Further, the radius of curvature TRc [mm] of the circular arc is in the range of 30 ⁇ TRc ⁇ 3000, preferably in the range of 50 ⁇ TRc ⁇ 2800, and more preferably in the range of 80 ⁇ TRc ⁇ 2500. Thereby, the load capacity of the tread portion is appropriately ensured.
- the center region of the tread portion becomes flat, the ground contact pressure of the tire ground contact region is made uniform, and the wear resistance performance of the tire is ensured.
- the above upper limit suppresses a decrease in wear life caused by excessive ground contact pressure in the shoulder region of the tread.
- small-diameter tires are expected to be used under high internal pressure and high load, and therefore, the effect of equalizing ground pressure under such usage conditions can be effectively achieved.
- the radius of curvature of the circular arc is measured with the tire mounted on a specified rim, a specified internal pressure applied, and an unloaded state.
- the radius of curvature TRw [mm] of the arc passing through the point C1 on the tire equatorial plane CL and the left and right tire ground contact edges T, T is 0.30 ⁇ relative to the tire outer diameter OD [mm].
- the radius of curvature TRw [mm] of the circular arc is in the range of 150 ⁇ TRw ⁇ 2800, preferably in the range of 200 ⁇ TRw ⁇ 2500.
- the above upper limit suppresses a decrease in wear life caused by excessive ground contact pressure in the shoulder region of the tread.
- small-diameter tires are expected to be used under high internal pressure and high load, so the above configuration can effectively optimize the ground pressure distribution in the tire ground contact area.
- the radius of curvature TRw [mm] of the first arc passing through the points C1 and C2 described above is 0.50 ⁇ TRw/with respect to the radius of curvature TRw [mm] of the second arc passing through the point C1 and the tire contact edge T It is in the range of TRc ⁇ 1.00, preferably in the range of 0.60 ⁇ TRw/TRc ⁇ 0.98, and more preferably in the range of 0.70 ⁇ TRw/TRc ⁇ 0.96.
- the ground contact shape of the tire is optimized.
- the lower limit allows the ground pressure in the center region of the tread portion to be dispersed, thereby improving the wear life of the tire.
- the above upper limit suppresses a decrease in wear life caused by excessive ground contact pressure in the shoulder region of the tread.
- a point B1 on the carcass layer 13 in the tire equatorial plane CL and legs B2, B2 of perpendicular lines drawn from the left and right tire contact edges T, T to the carcass layer 13 are defined.
- the radius of curvature CRw of the circular arc passing through point B1 and the pair of points B2, B2 is 0.35 ⁇ CRw/TRw ⁇ with respect to the radius of curvature TRw of the circular arc passing through point C1 and the tire contact edges T, T mentioned above. 1.60, preferably 0.45 ⁇ CRw/TRw ⁇ 1.50, more preferably 0.55 ⁇ CRw/TRw ⁇ 1.40. Further, the radius of curvature CRw [mm] is in the range of 100 ⁇ CRw ⁇ 2500, preferably in the range of 120 ⁇ CRw ⁇ 2200. This makes the tire ground contact shape more appropriate. Specifically, the above lower limit suppresses a decrease in wear life caused by an increase in the rubber gauge in the shoulder region of the tread. The above upper limit ensures the wear life of the center region of the tread portion.
- FIG. 5 is an enlarged view showing one side area of the tread portion shown in FIG. 4.
- the belt layer 14 has a pair of intersecting belts 141 and 142, and the tread rubber 15 has a cap tread 151 and an undertread 152.
- the distance Tce [mm] from the tread profile in the tire equatorial plane CL to the outer peripheral surface of the wide cross belt 141 is 0.008 ⁇ Tce/OD ⁇ 0 with respect to the tire outer diameter OD [mm]. .13, preferably 0.012 ⁇ Tce/OD ⁇ 0.10, more preferably 0.015 ⁇ Tce/OD ⁇ 0.07. Further, the distance Tce [mm] is in the range of 5 ⁇ Tce ⁇ 25, preferably in the range of 7 ⁇ Tce ⁇ 20. Thereby, the load capacity of the tread portion is appropriately ensured. Specifically, the above lower limit suppresses tire deformation during use under high load, ensuring the wear resistance performance of the tire.
- small-diameter tires are expected to be used under high internal pressure and high load, so the above-mentioned wear resistance performance can be significantly achieved.
- the above upper limit suppresses deterioration of rolling resistance due to an increase in the mass of the tread rubber.
- the distance Tce is measured when the tire is mounted on a specified rim, a specified internal pressure is applied, and there is no load.
- the outer peripheral surface of the belt ply is defined as the entire radially outer peripheral surface of the belt ply consisting of the belt cord and coated rubber.
- the distance Tce [mm] from the tread profile in the tire equatorial plane CL to the outer peripheral surface of the wide cross belt 141 satisfies the following formula (6) with respect to the tire outer diameter OD [mm].
- the distance Tsh [mm] from the tread profile at the tire ground contact edge T to the outer peripheral surface of the wide cross belt 141 is 0.60 ⁇ Tsh/Tce ⁇ 1.70 with respect to the distance Tce [mm] at the tire equatorial plane CL. It is preferably in the range of 0.80 ⁇ Tsh/Tce ⁇ 1.60, more preferably in the range of 1.01 ⁇ Tsh/Tce ⁇ 1.50.
- the above lower limit ensures the tread gauge in the shoulder region, thereby suppressing repeated deformation of the tire during tire rolling, and ensuring the wear resistance performance of the tire.
- the above upper limit ensures a tread gauge in the center region, tire deformation during use under high loads peculiar to small-diameter tires is suppressed, and the wear resistance performance of the tire is ensured.
- the distance Tsh is measured when the tire is mounted on a specified rim, a specified internal pressure is applied, and there is no load. Further, when there is no wide crossing belt directly under the tire ground contact edge T, the distance Tsh is measured as the distance from the tread profile to an imaginary line that is an extension of the outer peripheral surface of the belt ply.
- the distance Tsh [mm] from the tread profile at the tire ground contact edge T to the outer peripheral surface of the wide cross belt 141 satisfies the following formula (7) with respect to the distance Tce [mm] at the tire equatorial plane CL.
- a section having a width ⁇ TW of 10% of the tire ground contact width TW is defined.
- the ratio between the maximum value Ta and minimum value Tb of the rubber gauge of the tread rubber 15 in any section of the tire contact area is in the range of 0 [%] to 40 [%], preferably 0 [%]. It is in the range of 20 [%] or more.
- the ground contact pressure distribution in the tire width direction is smooth. This improves the wear resistance of the tire.
- the rubber gauge of the tread rubber 15 is defined as the distance from the tread profile to the inner peripheral surface of the tread rubber 15 (in FIG. 5, the distance from the outer peripheral surface of the cap tread 151 to the inner peripheral surface of the undertread 152). Therefore, the rubber gauge of the tread rubber 15 is measured while excluding the grooves formed on the tread surface.
- the rubber gauge UTce of the undertread 152 in the tire equatorial plane CL is in the range of 0.04 ⁇ UTce/Tce ⁇ 0.60, preferably 0. It is in the range of .06 ⁇ UTce/Tce ⁇ 0.50. Thereby, the rubber gauge UTce of the undertread 152 is optimized.
- the distance Tsh at the tire ground contact edge T mentioned above is in the range of 1.50 ⁇ Tsh/Tu ⁇ 6.90 with respect to the rubber gauge Tu [mm] from the end of the wide cross belt 141 to the outer peripheral surface of the carcass layer 13. It is preferably in the range of 2.00 ⁇ Tsh/Tu ⁇ 6.50.
- the profile of the carcass layer 13 is optimized and the tension of the carcass layer 13 is optimized.
- the above lower limit ensures the tension of the carcass layer and the tread gauge of the shoulder region, thereby suppressing repeated deformation of the tire during tire rolling, and ensuring the wear resistance performance of the tire. Due to the above upper limit, a rubber gauge near the end of the belt ply is secured, so that separation of the rubber around the belt ply is suppressed.
- the rubber gauge Tu is measured as a gauge of a rubber member (sidewall rubber 16 in FIG. 5) inserted between the end of the wide cross belt 141 and the carcass layer 13. Specifically, in a cross-sectional view in the tire meridian direction, a perpendicular line is drawn from the end of the wide cross belt 141 to the outer surface of the carcass layer 13, and the total gauge of the rubber member on this perpendicular line is calculated as the rubber gauge Tu. .
- the outer peripheral surface of the carcass layer 13 is defined as the entire radially outer peripheral surface of the carcass ply made of the carcass cord and coated rubber. Further, when the carcass layer 13 has a multilayer structure consisting of a plurality of carcass plies (not shown), the outer circumferential surface of the outermost carcass ply constitutes the outer circumferential surface of the carcass layer 13. Further, when the rolled up part 132 (see FIG. 1) of the carcass layer 13 exists between the end of the wide cross belt 141 and the carcass layer 13 (not shown), the outer circumferential surface of this rolled up part 132 is This constitutes the outer peripheral surface of No. 13.
- the sidewall rubber 16 is inserted between the end of the wide cross belt 141 and the carcass layer 13, and the rubber gauge Tu between the end of the wide cross belt 141 and the carcass layer 13 is is forming.
- a belt cushion may be inserted between the end of the wide cross belt 141 and the carcass layer 13 instead of the sidewall rubber 16 (not shown).
- the inserted rubber member has a rubber hardness Hs_sp of 46 or more and 67 or less, a modulus M_sp at 100 [%] elongation of 1.0 or more and 3.5 or less [MPa], and a rubber hardness of 0.02 or more and 0.22 or less.
- It has a loss tangent tan ⁇ _sp, preferably a rubber hardness Hs_sp of 48 or more and 63 or less, a modulus at 100 [%] elongation M_sp [MPa] of 1.2 or more and 3.2 or less, and a modulus M_sp [MPa] of 0.04 or more and 0.20 or less. It has a loss tangent tan ⁇ _sp.
- the tire 1 has a plurality of circumferential main grooves 21 to 23 (see FIG. 5) extending in the tire circumferential direction, and a land portion divided by these circumferential main grooves 21 to 23. (numerals omitted in the figure) are provided on the tread surface.
- the main groove is defined as a groove that is required to display a wear indicator as defined in JATMA.
- the groove depth Gd1 [mm] of the circumferential main groove 21 closest to the tire equatorial plane CL among the plurality of circumferential main grooves 21 to 23 is determined by the rubber gauge Gce[mm] of the tread rubber 15.
- mm] is in the range of 0.50 ⁇ Gd1/Gce ⁇ 1.00, preferably in the range of 0.55 ⁇ Gd1/Gce ⁇ 0.98. This ensures the wear resistance of the tire.
- the lower limit allows the ground pressure in the center region of the tread portion to be dispersed, thereby improving the wear life of the tire.
- the above upper limit ensures the rigidity of the land portion and also ensures the rubber gauge from the bottom of the circumferential main groove 21 to the belt layer.
- the circumferential main groove closest to the tire equatorial plane CL is defined as the circumferential main groove 21 (see FIG. 5) located on the tire equatorial plane CL, and when there is no circumferential main groove on the tire equatorial plane CL (not shown) ) is defined as the circumferential main groove closest to the tire equatorial plane CL.
- the ratio Gd1/Gce described above satisfies the following formula (8) with respect to the tire outer diameter OD [mm].
- the groove depth Gd1 [mm] of the circumferential main groove 21 closest to the tire equatorial plane CL is different from the groove depth Gd2 [mm] of the other circumferential main grooves 22 and 23. mm], Gd3 [mm] or more (Gd2 ⁇ Gd1, Gd3 ⁇ Gd1).
- the groove depth of the circumferential main groove (number omitted in the figure) closest to the tire equatorial plane CL is divided into two equal parts in the tire width direction.
- the groove depth Gd1 is 1.00 times or more and 2.50 times or less the maximum value of the groove depths Gd2 and Gd3 of other circumferential main grooves (numerals omitted in the figure) in the area on the tire contact edge T side. It is preferably in the range of 1.01 times or more and 2.00 times or less, more preferably in the range of 1.05 times or more and 1.80 times or less.
- the ground contact pressure in the center region of the tread portion is dispersed, and the wear resistance performance of the tire is improved.
- the above upper limit suppresses uneven wear caused by an excessive ground contact pressure difference between the tread center region and the shoulder region.
- FIG. 6 is an enlarged view showing a side fall portion and a bead portion of the tire 1 shown in FIG.
- FIG. 7 is an enlarged view showing the sidewall portion shown in FIG. 6.
- a point Al on the side profile at the same position in the tire radial direction with respect to the end is defined. Further, a distance Hu in the tire radial direction from the tire maximum width position Ac to a point Au, and a distance Hl in the tire radial direction from the tire maximum width position Ac to a point Al are defined.
- a point Au' on the side profile is located at a radial position of 70% of the distance Hu from the tire maximum width position Ac, and a side is located at a radial position of 70% of the distance Hl from the tire maximum width position Ac.
- a point Al' on the profile is defined.
- the sum of the distance Hu [mm] and the distance Hl [mm] is in the range of 0.45 ⁇ (Hu+Hl)/SH ⁇ 0.90 with respect to the tire cross-sectional height SH [mm] (see Fig. 2). 0.50 ⁇ (Hu+Hl)/SH ⁇ 0.85.
- the above lower limit ensures a deformable region of the tire side portion, thereby suppressing failure of the tire side portion (for example, separation of the rubber member at the radially outer end of the bead filler 12).
- the above upper limit ensures a deformable region of the tire side portion, thereby suppressing failure of the tire side portion (for example, separation of the rubber member at the radially outer end of the bead filler 12). With the above upper limit, the amount of deflection of the tire side portion when the tire is rolling is reduced, and the rolling resistance of the tire is reduced.
- the distance Hu and the distance Hl are measured with the tire mounted on a specified rim, a specified internal pressure applied, and an unloaded state.
- the sum of the distance Hu [mm] and the distance Hl [mm] is the tire outer diameter OD ( Figure 1), the tire cross-sectional height SH [mm] (see Figure 2), the tire maximum width position Ac, the points Au' and It is preferable that the following formula (9) be satisfied for the radius of curvature RSc [mm] of the arc passing through the point Al'.
- the radius of curvature RSc of the circular arc is measured with the tire mounted on a specified rim, a specified internal pressure applied, and an unloaded state.
- the distance Hu [mm] and the distance Hl [mm] have a relationship of 0.30 ⁇ Hu/(Hu+Hl) ⁇ 0.70, preferably 0.35 ⁇ Hu/(Hu+Hl) ⁇ 0.65. have a relationship whereby, the position of the tire maximum width position Ac in the deformable region of the tire side portion is optimized. Specifically, the lower limit alleviates stress concentration near the end of the belt ply caused by the tire maximum width position Ac being too close to the end of the belt layer 14, thereby suppressing separation of the surrounding rubber.
- the radius of curvature RSc [mm] of the arc passing through the tire maximum width position Ac, point Au' and point Al' is in the range of 0.05 ⁇ RSc/OD ⁇ 1.70 with respect to the tire outer diameter OD [mm]. and preferably in the range of 0.10 ⁇ RSc/OD ⁇ 1.60.
- the radius of curvature RSc [mm] of the circular arc is in the range of 25 ⁇ RSc ⁇ 330, preferably in the range of 30 ⁇ RSc ⁇ 300.
- the lower limit ensures the radius of curvature of the side profile and optimizes the carcass tension, thereby suppressing tire collapse and suppressing tire side cuts. Furthermore, the above upper limit suppresses side cuts in the tire due to excessive tension in the carcass layer 13.
- the radius of curvature RSc [mm] of the circular arc is in the range of 0.50 ⁇ RSc/SH ⁇ 0.99 with respect to the tire cross-sectional height SH [mm], preferably 0.55 ⁇ RSc/SH ⁇ 0. It is in the range of .97.
- the radius of curvature RSc [mm] of the circular arc satisfies the following formula (10) with respect to the tire outer diameter OD [mm] and the rim diameter RD [mm].
- a point Bc on the main body portion 131 of the carcass layer 13 is defined at the same position in the tire radial direction as the tire maximum width position Ac. Further, a point Bu' on the main body portion 131 of the carcass layer 13 is defined at a radial position of 70% of the distance Hu described above from the tire maximum width position Ac. Further, a point Bl' on the main body portion 131 of the carcass layer 13 is defined at a radial position of 70% of the distance Hl described above from the tire maximum width position Ac.
- the radius of curvature RSc [mm] of the arc passing through the tire maximum width position Ac, point Au' and point Al' is the radius of curvature RCc [mm] of the arc passing through point Bc, point Bu' and point Bl'. 1.10 ⁇ RSc/RCc ⁇ 4.00, preferably 1.50 ⁇ RSc/RCc ⁇ 3.50. Further, the radius of curvature RCc [mm] of the arc passing through point Bc, point Bu', and point Bl' is in the range of 5 ⁇ RCc ⁇ 300, preferably in the range of 10 ⁇ RCc ⁇ 270.
- the relationship between the radius of curvature RSc of the side profile of the tire and the radius of curvature RCc of the side profile of the carcass layer 13 is optimized.
- the above lower limit ensures the radius of curvature RCc of the carcass profile, the internal volume V of the tire described below, and the load capacity of the tire.
- the above upper limit ensures the total gauges Gu and Gl of the tire side portion, which will be described later, are ensured, and the load capacity of the tire side portion is ensured.
- the radius of curvature RSc [mm] of the side profile described above satisfies the following formula (11) with respect to the radius of curvature RCc [mm] of the carcass profile and the tire outer diameter OD [mm].
- the total gauge Gu [mm] of the tire side portion at the point Au described above is preferably in the range of 0.010 ⁇ Gu/OD ⁇ 0.080 with respect to the tire outer diameter OD [mm]. is in the range of 0.015 ⁇ Gu/OD ⁇ 0.050.
- the total gauge Gu of the radially outer region of the tire side portion is optimized.
- the above lower limit ensures the total gauge Gu of the radially outer region of the tire side portion, suppresses tire deformation during use under high load, and ensures tire durability.
- small-diameter tires are expected to be used under high internal pressure and high load, so the above-described effect of reducing the rolling resistance of the tire can be significantly achieved.
- the above upper limit suppresses deterioration of the rolling resistance of the tire due to the total gauge Gu becoming excessively large.
- the total gauge of the tire side part is measured as the distance from the side profile to the inner surface of the tire on a perpendicular line drawn from a predetermined point on the side profile to the main body part 131 of the carcass layer 13.
- the total gauge Gu [mm] at the point Au mentioned above is 1.30 ⁇ Gu/Gc ⁇ 5.00 with respect to the total gauge Gc [mm] of the tire side part at the tire maximum width position Ac. within the range, preferably within the range of 1.50 ⁇ Gu/Gc ⁇ 4.00.
- the gauge distribution in the tire side portion from the tire maximum width position Ac to the innermost layer of the belt layer 14 is optimized.
- the lower limit ensures the total gauge Gu in the radially outer region, suppresses tire deformation during use under high load, and ensures tire durability.
- the above upper limit suppresses deterioration of the rolling resistance of the tire due to the total gauge Gu becoming excessively large.
- the total gauge Gu [mm] at the above point Au satisfies the following formula (12) with respect to the total gauge Gc [mm] at the tire maximum width position Ac and the tire outer diameter OD [mm].
- the total gauge Gc [mm] of the tire side portion at the tire maximum width position Ac has a relationship of 0.003 ⁇ Gc/OD ⁇ 0.060 with respect to the tire outer diameter OD [mm]. , preferably has a relationship of 0.004 ⁇ Gc/OD ⁇ 0.050.
- the total gauge Gc at the tire maximum width position Ac is ensured, and the load capacity of the tire is ensured.
- the above upper limit ensures that the rolling resistance of the tire is reduced by thinning the total gauge Gc at the tire maximum width position Ac.
- the total gauge Gc [mm] at the tire maximum width position Ac satisfies the following formula (13) with respect to the tire outer diameter OD [mm].
- the total gauge Gc [mm] at the tire maximum width position Ac satisfies the following formula (14) with respect to the tire outer diameter OD [mm] and the tire total width SW [mm].
- the total gauge Gc [mm] at the tire maximum width position Ac is expressed by the following formula (15) for the radius of curvature RSc [mm] of the arc passing through the tire maximum width position Ac, points Au' and points Al'. It is preferable to satisfy the following.
- the total gauge Gl [mm] of the tire side portion at the above-mentioned point Al is in the range of 0.010 ⁇ Gl/OD ⁇ 0.150 with respect to the tire outer diameter OD, preferably 0.010 ⁇ Gl/OD ⁇ 0.150. 015 ⁇ Gl/OD ⁇ 0.100.
- the total gauge Gl in the radially inner region of the tire side portion is optimized.
- the above lower limit ensures the total gauge Gl of the radially inner region of the tire side portion, suppresses tire deformation during use under high load, and ensures tire durability.
- small-diameter tires are expected to be used under high internal pressure and high load, so the above-described effect of reducing the rolling resistance of the tire can be significantly achieved.
- the above upper limit suppresses deterioration of the rolling resistance of the tire due to the total gauge Gl becoming excessively large.
- the ratio Gl/Gc between the total gauge Gl [mm] of the tire side part at the above-mentioned point Al and the total gauge Gc [mm] of the tire side part at the tire maximum width position Ac is 1.00 ⁇ Gl/Gc ⁇ 7.00, preferably 1.50 ⁇ Gl/Gc ⁇ 4.00.
- the gauge distribution in the tire side portion from the tire maximum width position Ac to the bead core 11 is optimized.
- the above lower limit ensures the total gauge Gl in the radially inner region, suppresses tire deformation during use under high load, and ensures tire durability.
- the above upper limit suppresses deterioration of the rolling resistance of the tire due to the total gauge Gl becoming excessively large.
- the total gauge Gl [mm] of the tire side portion at the above-mentioned point Al satisfies the following formula (16) with respect to the total gauge Gc [mm] at the tire maximum width position Ac and the tire outer diameter OD [mm]. It is preferable.
- the total gauge Gl [mm] at the above-mentioned point Al is preferably in the range of 0.50 ⁇ Gl/Gu ⁇ 5.00 with respect to the total gauge Gu [mm] at the above-mentioned point Au. is in the range of 1.00 ⁇ Gl/Gu ⁇ 3.00.
- the total gauge Gl [mm] at the above-mentioned point Al satisfies the following formula (17) with respect to the total gauge Gu [mm] at the above-mentioned point Au and the tire outer diameter OD [mm].
- the average rubber hardness Hsc at the measurement position of the total gauge Gc, the average rubber hardness Hsu at the measurement position of the total gauge Gu, and the average rubber hardness Hsl at the measurement point position of the total gauge Gl are as follows.
- the relationship is ⁇ 23. As a result, the relationship between the rubber hardness of the tire side portions is optimized.
- the average rubber hardness Hsc, Hsu, Hsl is the cross-sectional length of each rubber member at each measurement point of the total gauge Gc [mm] at the tire maximum width position Ac, the total gauge Gu at point Au, and the total gauge Gl at point Al. It is calculated as the sum of the product of rubber hardness and rubber hardness divided by the total gauge.
- the distance ⁇ Au' [mm] in the tire width direction from the tire maximum width position Ac to the point Au' is 0 for 70% of the distance Hu [mm] from the tire maximum width position Ac. It is in the range of .03 ⁇ Au'/(Hu ⁇ 0.70) ⁇ 0.25, preferably in the range of 0.07 ⁇ Au′/(Hu ⁇ 0.70) ⁇ 0.23.
- the degree of curvature of the side profile in the radially outer region is optimized.
- the above lower limit alleviates stress concentration caused by flattening of the tire side portion, and improves the durability performance of the tire.
- the above upper limit the amount of deflection of the tire side portion when the tire is rolling is reduced, and the rolling resistance of the tire is reduced.
- the lower limit ensures the radius of curvature of the side profile and optimizes the carcass tension, thereby suppressing tire collapse and suppressing tire side cuts. Furthermore, the above upper limit suppresses side cuts in the tire due to excessive tension in the carcass layer 13.
- the distance ⁇ Al' [mm] in the tire width direction from the tire maximum width position Ac to the point Al' is 0.03 ⁇ Al'/ for 70% of the distance Hl [mm] from the tire maximum width position Ac. It is in the range of (Hl ⁇ 0.70) ⁇ 0.28, preferably in the range of 0.07 ⁇ Al′/(Hl ⁇ 0.70) ⁇ 0.20.
- the degree of curvature of the side profile in the radially inner region is optimized.
- the above lower limit alleviates stress concentration caused by flattening of the tire side portion, and improves the durability performance of the tire.
- the bead core 11 is reinforced as described above, stress concentration near the bead core 11 is effectively suppressed.
- the above upper limit the amount of deflection of the tire side portion when the tire is rolling is reduced, and the rolling resistance of the tire is reduced.
- the distances ⁇ Au' and ⁇ Al' are measured when the tire is mounted on a specified rim, a specified internal pressure is applied, and there is no load.
- the distance ⁇ Au' [mm] in the tire width direction from the tire maximum width position Ac to the point Au' is the radius of curvature RSc [mm] of the arc passing through the tire maximum width position Ac, the point Au', and the point Al'. It is preferable that the following formula (18) be satisfied for .
- the distance ⁇ Bu' [mm] in the tire width direction from point Bc to point Bu' is 1 for the distance ⁇ Au' [mm] in the tire width direction from the tire maximum width position to point Au'. It is in the range of .00 ⁇ Bu'/ ⁇ Au' ⁇ 7.00, preferably in the range of 1.10 ⁇ Bu'/ ⁇ Au' ⁇ 6.00.
- This optimizes the relationship between the degree of curvature of the side profile and the degree of curvature of the carcass profile in the radially outer region.
- the cut resistance of the tire side portion is ensured by the above lower limit.
- the above upper limit ensures the tension of the carcass layer 13, the rigidity of the tire side parts, and the load capacity and durability of the tire.
- the distance ⁇ Bl' [mm] in the tire width direction from point Bc to point Bl' is relative to the distance ⁇ Al' [mm] in the tire width direction from the tire maximum width position Ac to point Al'. It is in the range of 2.00 ⁇ Bl'/ ⁇ Al' ⁇ 11.0, preferably in the range of 1.90 ⁇ Bl'/ ⁇ Al' ⁇ 9.50.
- This optimizes the relationship between the degree of curvature of the side profile and the degree of curvature of the carcass profile in the radially inner region.
- the total gauge Gl of the tire side portion is ensured by the above lower limit, and the load capacity of the tire side portion is ensured.
- the above upper limit ensures the tension of the carcass layer 13, the rigidity of the tire side parts, and the load capacity and durability of the tire.
- the distances ⁇ Bu' and ⁇ Bl' are measured when the tire is mounted on a specified rim, a specified internal pressure is applied, and there is no load.
- the distance ⁇ Bu' [mm] in the tire width direction from point Bc to point Bu' is calculated using the following formula for the radius of curvature RCc [mm] of the arc passing through the points Bc, Bu', and Bl' mentioned above. It is preferable that (19) is satisfied.
- the rubber gauge Gcr [mm] of the sidewall rubber 16 at the tire maximum width position Ac is 0.35 ⁇ Gcr/Gc ⁇ 0 with respect to the above-mentioned total gauge Gc [mm] at the tire maximum width position Ac. It is in the range of .90. Further, the rubber gauge Gcr [mm] of the sidewall rubber 16 is in the range of 1.5 ⁇ Gcr, preferably in the range of 2.0 ⁇ Gcr. With the above lower limit, the rubber gauge Gcr [mm] of the sidewall rubber 16 is ensured, and the load capacity of the sidewall portion is ensured.
- the rubber gauge Gcr [mm] of the sidewall rubber 16 at the tire maximum width position Ac is determined by the following formula (20 ) is preferably satisfied.
- the rubber gauge Gin [mm] (not shown) of the inner liner 18 at the tire maximum width position Ac is 0.03 ⁇ Gin/Gc ⁇ with respect to the total gauge Gc [mm] at the tire maximum width position Ac. It is in the range of 0.50, preferably in the range of 0.05 ⁇ Gin/Gc ⁇ 0.40. Thereby, the inner surface of the carcass layer 13 is properly protected.
- FIG. 8 is an explanatory diagram showing a laminated structure of a carcass layer and a belt layer of the tire shown in FIG. 1. This figure shows an enlarged cross-sectional view in the tire meridian direction.
- the carcass layer 13 consists of a single-layer carcass ply 13A formed by covering a carcass cord 13cc with a coated rubber 13cr, and the belt layer 14 consists of a belt cord 14bc coated with rubber. It is constructed by laminating a pair of crossed belts 141 and 142 coated with 14cr. Further, an inner liner 18 is arranged to cover the inner peripheral surface of the carcass layer 13.
- the present invention is not limited to the above, and the carcass layer 13 may be constructed by laminating two carcass plies (see FIG. 9 described later).
- the carcass ply 13A (the innermost carcass ply in a structure in which the carcass layer 13 is formed by laminating two carcass plies (not shown)) in the area between points B2 and B2 in FIG.
- the distance TL [mm] from the center of the outer diameter of the carcass cord 13cc to the inner surface of the tire is in the range of 0.00005 ⁇ TL/OD ⁇ 0.01000 with respect to the tire outer diameter OD [mm] (see Fig. 1). , preferably in the range of 0.00008 ⁇ TL/OD ⁇ 0.00900.
- the distance TL [mm] is in the range of 0.00050 ⁇ TL/SW ⁇ 0.02500 with respect to the total tire width SW [mm] (see Fig.
- the minimum value TL_min of the distance TL [mm] is 0.10 ⁇ TL_min.
- the minimum value TL_min and maximum value TL_max of the distance TL [mm] in the area between points B2 and B2 in FIG. 4 have a relationship of 0.30 ⁇ TL_min/TL_max ⁇ 1.00, preferably 0. The relationship is .40 ⁇ TL_min/TL_max ⁇ 1.00.
- the distance TL [mm] is defined at any measurement point in the area between the two points B2 and B2 (see FIG. 4) described above.
- the distance TL [mm] is 1/350000 ⁇ TL/(SW ⁇ (OD -RD)) ⁇ 1/3760.
- the carcass ply 13A at any point in the area between points B2 and B2 in FIG. 8 is equal to the distance TL [mm] from the center of the carcass cord 13cc of the innermost carcass ply 13A to the inner surface of the tire.
- it is in the range of 0.09 ⁇ TCSU/TL ⁇ 4.50, preferably in the range of 0.10 ⁇ TCSU/TL ⁇ 4.00.
- the above lower limit appropriately suppresses air leakage, and the above upper limit suppresses an increase in tire weight.
- the modulus MC [MPa] of the coat rubber 13cr of the carcass ply 13A at 100 [%] elongation is the same as the modulus MIL [MPa] of the inner liner 18 at 100 [%] elongation and the innermost layer of the belt layer 14.
- the modulus MB [MPa] of the coating rubber 14cr of the belt ply 141 at 100 [%] elongation is in the range of MIL ⁇ MC ⁇ MB.
- the ratio MC/MIL is in the range of 1.00 ⁇ MC/MIL ⁇ 5.00, preferably in the range of 1.10 ⁇ MC/MIL ⁇ 4.50.
- the ratio MB/MC is in the range of 1.00 ⁇ MB/MC ⁇ 2.40, preferably in the range of 1.00 ⁇ MB/MC ⁇ 2.20.
- the modulus MC [MPa] of the coat rubber 13cr of the carcass ply 13A is in the range of 1.5 ⁇ MC ⁇ 12.0, preferably in the range of 2.0 ⁇ MC ⁇ 10.0.
- the product of the thickness TC [mm] of the carcass ply 13A and the loss tangent tan ⁇ of the coating rubber 13cr of the carcass ply 13A at 60 [°C] satisfies 0.05 ⁇ TC ⁇ tan ⁇ 0.55. preferably within the range of 0.07 ⁇ TC ⁇ tan ⁇ 0.50.
- FIG. 9 is an explanatory diagram showing a modification of the laminated structure of the carcass layer 13 and belt layer 14 shown in FIG. 8.
- the carcass layer 13 is composed of the single layer carcass ply 13A as described above.
- the carcass cord 13cc of the carcass ply 13A is made of inorganic fiber, particularly steel cord.
- the carcass layer 13 may have a structure in which two carcass plies 13A and 13B are laminated.
- the carcass cords 13cc of the carcass plies 13A and 13B are made of organic fiber material.
- a peeling force Hpp [N /25mm] is in the range of 90 ⁇ Hpp/TCB ⁇ 300 with respect to the distance TCB [mm] from the center of the outer diameter of the carcass cord 13cc of the carcass ply 13B to the center of the outer diameter of the belt cord 14bc of the belt ply 141. It is preferable that the range is 100 ⁇ Hpp/TCB ⁇ 250.
- the peeling force Hpp [N/25mm] is in the range of 1.50 ⁇ Hpp/Ecs ⁇ 15.0, preferably 1.50 ⁇ Hpp/Ecs ⁇ 15.0 with respect to the number of installed carcass cords Ecs [pieces/50mm] of 13cc of carcass cords of the carcass ply. It is in the range of 80 ⁇ Hpp/Ecs ⁇ 10.0. This ensures the durability of the tire.
- the peeling force Hpp [N/25mm] has a long rectangular shape in the extending direction of the carcass cord, a width of 25 [mm], and a length of 100 [mm] or more (preferably about 50 [mm]).
- a test sample having a length of 150 [mm] or more (including the test gripping margin) is used, and it is calculated as the average value of the maximum and minimum peak values of the analyzed wavy curve. Further, it is preferable that the number of test samples is two or more.
- FIG. 10 is an explanatory diagram showing a modification of the laminated structure of the carcass layer 13 and belt layer 14 shown in FIG. 8.
- the belt layer 14 is composed of a pair of intersecting belts 141, 142, a belt cover 143, and a pair of belt edge covers 144, 144. Further, as shown in FIG. 8, a pair of cross belts 141 and 142 are laminated adjacent to the outer peripheral surface of the carcass layer 13.
- the belt layer 14 includes an additional belt 145, which is a third intersecting belt.
- the additional belt 145 is laminated around the outer periphery of the pair of intersecting belts 141 and 142.
- the distance Hb between the cords of adjacent belt plies among the pair of crossed belts 141, 142 and the additional belt 145 (in FIG. 10, the distance Hb1 between the cords of the pair of crossed belts 141, 142, and the outer diameter The inter-cord distance Hb2) of the side crossing belt 142 and the additional belt 145 is defined.
- the distance between cords Hb_sh (not shown) at the ends of at least one set of belt plies is 1.05 ⁇ Hb_sh/Hb_ce ⁇ 2.00 with respect to the distance between cords Hb_ce (not shown) in the tire equatorial plane CL. It is preferably in the range of 1.50 ⁇ Hb_sh/Hb_ce ⁇ 1.80.
- the inter-cord distance Hb is set large in the tread center region.
- the above lower limit allows the belt layer 14 to effectively suppress the tire outer diameter growth, and the above upper limit ensures the durability of the belt layer.
- the above configuration is realized, for example, by making the gauge of the coated rubber of the belt ply thicker in the center region of the tread portion, or by inserting an additional rubber sheet between adjacent belt plies (not shown).
- FIG. 11 is an enlarged view showing the tire radially outer region shown in FIG. 6.
- FIG. 11 is an enlarged view showing the tire radially outer region shown in FIG. 6.
- Point An on the side profile located at a radial position of 35% of the distance Hu described above from the tire maximum width position Ac is defined.
- Point An corresponds to the midpoint between the tire maximum width position Ac in the tire radial direction and the above-mentioned point Au' on the side profile.
- the radius of curvature RP [mm] of the circular arc passing through the tire maximum width position Ac, point Au', and point Am when the tire is mounted on the specified rim, the specified internal pressure is applied, and the tire is in an unloaded state is the cross section of the tire.
- the height SH [mm] (see FIG. 2) is in the range of 0.20 ⁇ RP/SH ⁇ 1.80, preferably in the range of 0.70 ⁇ RP/SH ⁇ 1.60.
- the radius of curvature RP [mm] of the arc in the above-mentioned no-load state is in the range of 30 ⁇ RP ⁇ 250, preferably in the range of 50 ⁇ RP ⁇ 200.
- the side profile has a single inflection in the area from the tire maximum width position Ac to the point Au near the end of the innermost layer 141 of the belt layer 14 (the area of the above-mentioned distance Hu). It has a gentle S-shape with a point (not shown), and from this inflection point, the area on the tire maximum width position Ac side is convex to the outside of the tire, and the area on the buttress side is convex to the inside of the tire. have. Further, the S-shaped inflection point is near the point Au' located at a radial position of 70% of the distance Hu.
- the side profile has a substantially circular arc shape that is convex toward the outside of the tire in the area from the tire maximum width position Ac to the point Au'. Therefore, the arc defining the radius of curvature RP [mm] has a shape that is convex toward the outside of the tire.
- the radius of curvature RP of the side profile in the tire radial outer region from the tire side part to the buttress part is optimized, the tire's ground contact performance and durability are compatible, and the tire's load capacity is properly adjusted.
- the above-mentioned lower limit of the ratio RP/SH reduces the amount of deflection of the tire radially outer region when the tire rolls, and prevents the ground contact length of the tread shoulder region from becoming excessively long. Thereby, the ground contact shape of the tire is optimized, and the ground contact performance (especially noise performance) of the tire is ensured.
- the above upper limit of the ratio RP/SH alleviates stress concentration caused by flattening of the tire's radially outer region, thereby improving tire durability.
- the radius of curvature RP [mm] of the circular arc is in the range of 60 ⁇ RP/(SH/DW) ⁇ 290 with respect to the tire cross-sectional width DW [mm] and the tire cross-sectional height SH [mm]. It is preferably in the range of 150 ⁇ RP/(SH/DW) ⁇ 250.
- the radius of curvature RP of the circular arc is optimized with respect to the aspect ratio SH/DW of the tire 1.
- the above lower limit reduces the amount of deflection of the radially outer region of the tire when the tire rolls, thereby ensuring the ground contact performance of the tire.
- stress concentration in the tire radially outer region is alleviated, and the tire durability performance is improved.
- the radius of curvature RP' [mm] of a circular arc passing through (not shown) is defined.
- the radius of curvature RP' [mm] of the arc in the above-mentioned no-load state is 1.10 ⁇ RP/RP' with respect to the radius of curvature RP' [mm] of the arc under 100 [%] of the specified load. It is in the range of ⁇ 2.80, preferably in the range of 1.15 ⁇ RP/RP' ⁇ 2.60.
- the radius of curvature RP' when applying a 100[%] load is optimized.
- the above lower limit ensures the amount of deflection of the radially outer region of the tire when a load is applied, that is, when the load increases, and the stress concentration in the radially outer region of the tire is alleviated.
- the above upper limit reduces the amount of deflection of the radially outer region of the tire when the tire rolls, thereby ensuring the ground contact performance of the tire.
- the radius of curvature RP'' [mm] of an arc passing through the three points Ac, Au', and An (not shown) displaced by the application of a load of 150% of the specified load is defined.
- the radius of curvature RP' [mm] of the arc when a load of 100 [%] is applied is the radius of curvature RP' [mm] of the arc when a load of 150 [%] of the specified load is applied.
- the radius of curvature RP" when a load is applied is optimized.
- the above lower limit ensures the amount of deflection of the radially outer region of the tire during use under high load, thereby relieving stress concentration in the radially outer region of the tire.
- the above upper limit reduces the amount of deflection of the tire radially outer region during tire rolling, that is, the amount of repeated deformation, and ensures the ground contact performance of the tire.
- the belt layer 14 includes a pair of intersecting belts 141 and 142 having cord angles of opposite signs (see FIG. 3).
- the cord angle B ⁇ (B ⁇ 1, B ⁇ 2) of the pair of crossing belts 141 and 142 is in the range of 15 [deg] or more and 55 [deg] or less in absolute value, preferably 15 [deg] or more and 35 [deg] or less. within the range of At this time, each of the cord angles B ⁇ [deg] of the pair of crossing belts 141 and 142 is in the range of 1000 ⁇ B ⁇ RP ⁇ 7700 with respect to the radius of curvature RP [mm] of the circular arc of the tire radial direction outer region.
- the product B ⁇ RP is optimized. Specifically, the lower limit of the product B ⁇ RP prevents the ground contact length of the tread shoulder region from becoming excessively long, and ensures the ground contact performance (especially noise performance) of the tire.
- the upper limit of the product B ⁇ RP ensures the hoop effect of the intersecting belts 141 and 142, and also relieves stress concentration in the tire radially outer region, improving tire durability.
- FIG. 12 is an explanatory diagram showing the laminated structure of the carcass layer 13 and the inner liner 18 in the radially outer region of the tire shown in FIG. 11.
- the foot of a perpendicular line drawn from a point Au on the side profile at the same position in the tire radial direction to the end of the innermost layer 141 of the belt layer 14 to the carcass layer 13 is defined as a point Iu. Further, the foot of a perpendicular line drawn from the tire maximum width position Ac to the carcass layer 13 is defined as a point Ic. As shown in FIG. 11, point Iu and point Ic correspond to the respective measurement positions of the total gauges Gu and Gc described above.
- the carcass layer 13 is formed by covering the carcass cord 13cc with the coat rubber 13cr. Furthermore, in the configuration of FIG. 12, the carcass layer 13 is composed of a single layer carcass ply 13A. However, the present invention is not limited to this, and the carcass layer 13 may be composed of a plurality of carcass plies (see FIG. 9).
- the innermost layer 13A of the carcass ply 13A (the innermost carcass ply in the structure in which the carcass layer 13 is formed by laminating two carcass plies (not shown)) in the region from point Iu to point Ic in FIG.
- the distance TLu [mm] (see Fig. 12) from the center of the carcass cord 13cc to the inner surface of the tire is 0.00010 ⁇ TLu/OD ⁇ 0.01500 with respect to the tire outer diameter OD [mm] (see Fig. 1). It is preferably in the range of 0.00015 ⁇ TLu/OD ⁇ 0.01200.
- the ratio TLu/OD is in the range of 0.00090 ⁇ TLu/OD ⁇ 0.01500, preferably 0.00100. It is in the range of ⁇ TLu/OD ⁇ 0.01200.
- the ratio TLu/OD is in the range of 0.00010 ⁇ TLu/OD ⁇ 0.00200. , preferably in the range of 0.00015 ⁇ TLu/OD ⁇ 0.00100.
- the distance TLu from the carcass layer 13 to the inner surface of the tire in the region from the end of the belt layer 14 to the tire maximum width position Ac is optimized.
- the lower limit ensures the distance TLu from the carcass layer 13 to the inner surface of the tire in the region where air leakage is likely to occur, thereby suppressing a decrease in tire durability performance and deterioration of rolling resistance due to air leakage. be done.
- the above upper limit suppresses deterioration of rolling resistance due to an increase in tire weight. This achieves both tire durability and low rolling resistance.
- small-diameter tires are used under the above-mentioned high internal pressure and high load, so stress concentration tends to occur easily. Therefore, when the above configuration is adopted for a small diameter tire, the durability performance and low rolling resistance performance of the tire can be significantly improved.
- the minimum value TLu_min and maximum value TLu_max of the distance TLu [mm] (see FIG. 12) in the area from point Iu to point Ic in FIG. 11 have a relationship of 0.30 ⁇ TLu_min/TLu_max ⁇ 1.00. , preferably has a relationship of 0.40 ⁇ TLu_min/TLu_max ⁇ 1.00.
- the distance TLu [mm] is in the range of 0.1 ⁇ TLu ⁇ 4.0, preferably in the range of 0.5 ⁇ TLu ⁇ 3.5.
- the lower limit ensures a distance TLu from the carcass cord 13cc to the inner surface of the tire, and air leakage is appropriately suppressed, and the upper limit suppresses deterioration of rolling resistance due to increase in tire weight.
- TLu_min/TLu_max For example, in the configuration of FIG. 11, TLu_min/TLu_max ⁇ 1.00, and the position where the distance TLu takes the maximum value TLu_max is closer to the point Ic (that is, the tire maximum width position Ac side) than the position where the distance TLu takes the minimum value TLu_min.
- the position where the maximum value TLu_max is taken is in the region from point Ic to 35% of the distance Hu in FIG. 11 (that is, the region from point Ac to point An).
- the position where the minimum value TLu_min is taken is in the area from the point Iu to 35% of the distance Hu in FIG.
- the distance TLu monotonically increases from the position where the minimum value TLu_min is taken to the position where the maximum value TLu_max is taken.
- the minimum value Ga_min (see FIG. 11) of the total gauge Ga [mm] of the tire side part in the area from point Iu to point Ic in FIG. 11, and the distance TLu' [mm] corresponding to the above distance TLu at the same position. (dimension symbols omitted in the figure) have a relationship of 0.05 ⁇ TLu'/Ga_min, preferably a relationship of 0.10 ⁇ TLu'/Ga_min (see FIG. 12).
- the total gauge Ga at the tire side portion becomes the minimum at the tire maximum width position Ac, and therefore the minimum value Ga_min matches the total gauge Gc. Further, the distance TLu' is measured at the tire maximum width position Ac where the total gauge Ga takes the minimum value Ga_min. Note that the upper limit of the ratio TLu'/Ga_min is not particularly limited, but is restricted by the upper limit of the distance TLu.
- the minimum value Ga_min of the total gauge Ga [mm] of the tire side part in the area from point Iu to point Ic in FIG. 11 and the distance TLu' [mm] corresponding to the above distance TLu at the same position are outside the tire.
- the diameter OD [mm] is in the range of 0.005 ⁇ (Ga_min+TLu')/OD ⁇ 0.040, preferably in the range of 0.006 ⁇ (Ga_min+TLu')/OD ⁇ 0.030.
- the distance TLu [mm] in the region from point Iu to point Ic in FIG. 11 is 0.005 with respect to the oxygen permeability coefficient ⁇ [mm ⁇ cc/(m ⁇ 2 ⁇ day ⁇ mmHg)]
- the relationship is ⁇ ( ⁇ (1/2))/TLu ⁇ 1.800, preferably 0.008 ⁇ ( ⁇ (1/2))/TLu ⁇ 1.500.
- the oxygen permeability coefficient ⁇ of the inner liner 18 is in the range of 0.0008 ⁇ 0.3500, and preferably in the range of 0.0010 ⁇ 0.3000.
- the oxygen permeability coefficient ⁇ is an index that indicates how much oxygen permeates through the material constituting the inner liner 18, and is based on JIS K 7126 at a relative temperature of 21 [°C] and a relative humidity of 50 [%]. measured.
- the dynamic storage elastic modulus ⁇ [MPa] of the inner liner 18 is in the range of 1 ⁇ 200, and preferably in the range of 2 ⁇ 150. Thereby, while ensuring the crack resistance of the inner liner 18, it is possible to improve the internal pressure retention property against air leakage.
- the dynamic storage elastic modulus ⁇ was measured using a viscoelastic spectrometer manufactured by Toyo Seiki Co., Ltd. using a test piece cut into a rectangular shape with a width of 5 mm and a length of 60 mm, at a static strain of 5% and a dynamic strain of ⁇ 0. 1%, a frequency of 20 Hz, and a temperature of 60°C.
- the ends of its constituent members are connected so as to overlap each other in order to suppress air leakage.
- the splice amount Is [mm] (not shown) of the inner liner 18 in the region from point Iu to point Ic in FIG. On the other hand, it is in the range of 0.010 ⁇ Is/OD ⁇ 0.100, preferably in the range of 0.015 ⁇ Is/OD ⁇ 0.080. Further, the splice amount Is [mm] of the inner liner 18 is in the range of 8 ⁇ Is ⁇ 20.
- the above lower limit appropriately suppresses air leakage, and the above upper limit suppresses deterioration of rolling resistance due to an increase in tire weight.
- the legs of the perpendicular line drawn from the left and right tire ground contact ends T, T to the carcass layer 13 are defined as points B2, B2, respectively.
- the minimum value TL_min of the distance TL [mm] (see FIG. 8) from the center of the carcass cord 13cc of the innermost layer 13A of the carcass ply to the inner surface of the tire in the area between points B2 and B2 is defined.
- the minimum value TLu_min of the distance TLu [mm] (see FIG. 12) in the region from point Iu to point Ic in FIG. 11 is the minimum value TLu_min of the distance TL [mm] in the region between points B2 and B2 in FIG.
- the value TL_min is in the range of 1.00 ⁇ TLu_min/TL_min, preferably in the range of 1.05 ⁇ TLu_min/TL_min. Therefore, the distance TLu in the region from point Iu to point Ic is set so that the distance from the carcass ply to the inner surface of the tire does not become relatively thin in the region where air leakage is likely to occur. As a result, the distance TL from the carcass ply to the inner surface of the tire in the region from point Iu to point Ic where air leakage is likely to occur is relatively secured, and air leakage is effectively suppressed.
- This tire 1 includes a pair of bead cores 11, 11, a carcass layer 13 spanning the bead cores 11, 11, and a belt layer 14 disposed on the radially outer side of the carcass layer 13. (See Figure 1). Further, the tire outer diameter OD [mm] is in the range of 200 ⁇ OD ⁇ 660, and the tire total width SW [mm] is in the range of 100 ⁇ SW ⁇ 400. Further, in a cross-sectional view in the tire meridian direction, a point Au on the side profile is defined at the same position in the tire radial direction with respect to the end of the innermost layer 141 of the belt layer 14.
- the foot of the perpendicular line drawn from point Au to the carcass layer 13 is defined as point Iu
- the foot of the perpendicular line drawn from the tire maximum width position Ac to the carcass layer is defined as point Ic.
- the carcass layer 13 is composed of a single layer (see FIG. 8) or a plurality of layers (see FIG. 9) of carcass ply, which is formed by covering a carcass cord 13cc with a coating rubber 13cr.
- the distance TLu [mm] see Fig.
- the tire outer diameter OD [mm] (see Fig. 1 ) is in the range of 0.00010 ⁇ TLu/OD ⁇ 0.01500.
- This configuration has the advantage that the distance TLu from the carcass layer 13 to the inner surface of the tire in the region from the end of the belt layer 14 to the tire maximum width position Ac is optimized.
- the lower limit ensures the distance TLu from the carcass layer 13 to the inner surface of the tire in the region where air leakage is likely to occur, thereby suppressing a decrease in tire durability performance and deterioration of rolling resistance due to air leakage. be done.
- the above upper limit suppresses deterioration of rolling resistance due to an increase in tire weight. This achieves both tire durability and low rolling resistance.
- small-diameter tires are used under the above-mentioned high internal pressure and high load, so stress concentration tends to occur easily. Therefore, when the above configuration is adopted for a small diameter tire, the durability performance and low rolling resistance performance of the tire can be significantly improved.
- the distance TLu [mm] in the region from point Iu to point Ic is 0.1 ⁇ TLu ⁇ 4. It is in the range of 0.
- the above lower limit has the advantage that the distance TLu from the carcass cord 13cc to the inner surface of the tire is ensured, and air leakage is appropriately suppressed, and the above upper limit suppresses deterioration of rolling resistance due to an increase in tire weight.
- the total gauge Ga [mm] of the tire side portion in the area from point Iu to point Ic is (see FIG. 11) and a distance TLu' [mm] corresponding to the distance TLu at the same position have a relationship of 0.05 ⁇ TLu'/Ga_min (see FIG. 12).
- This has the advantage that the distance TLu' from the carcass cord 13cc to the inner surface of the tire at the position where the total gauge Ga is thin is ensured, and air leakage is appropriately suppressed.
- the distance TLu [mm] in the region from point Iu to point Ic is It has a relationship of 0.005 ⁇ ( ⁇ (1/2))/TLu ⁇ 1.800 for the oxygen permeability coefficient ⁇ [mm ⁇ cc/(m ⁇ 2 ⁇ day ⁇ mmHg)]. This has the advantage of ensuring crack resistance of the inner liner 18 and improving internal pressure retention against air leakage.
- the splice amount Is [mm] of the inner liner 18 in the region from point Iu to point Ic is (not shown) is in the range of 0.01 ⁇ Is/OD ⁇ 0.10 with respect to the tire outer diameter OD [mm].
- the above lower limit has the advantage of appropriately suppressing air leakage
- the above upper limit has the advantage of suppressing deterioration of rolling resistance due to an increase in tire weight.
- each of the legs of the perpendicular line drawn from the left and right tire ground contact ends T, T to the carcass layer 13 are defined as points B2 and B2 (see FIG. 4).
- the minimum value TLu_min of the distance TLu [mm] (see FIG. 12) in the region from point Iu to point Ic is from the center of the carcass cord 13crc of the innermost layer 13A of the carcass ply in the region between points B2 and B2.
- the minimum value TL_min of the distance TL [mm] (see FIG. 8) to the inner surface of the tire is in the range of 1.00 ⁇ TLu_min/TL_min.
- the strength Tcs [N /50mm] is in the range of 17 ⁇ Tcs/OD ⁇ 120 with respect to the tire outer diameter OD [mm].
- the above lower limit suppresses tire deformation during use under high loads and ensures tire durability.
- small-diameter tires are expected to be used under high internal pressure and high loads, so the above-described tire durability and rolling resistance reduction effect can be significantly achieved.
- the above upper limit suppresses deterioration of rolling resistance due to increase in mass of the carcass layer.
- the carcass ply of the carcass layer 13 is constructed by covering a carcass cord made of steel with a coated rubber. Further, the cord diameter ⁇ cs [mm] of the carcass cord is in the range of 0.15 ⁇ cs ⁇ 1.10. Further, the number of carcass cords driven in Ecs [pieces/50 mm] is in the range of 25 ⁇ Ecs ⁇ 80. This has the advantage of realizing the strong Tcs of the carcass layer 13 described above.
- the carcass cord is formed by twisting a plurality of strands, and the strand diameter ⁇ css [mm] of the carcass cord is the same as that of the carcass cord. It is in the range of 0.30 ⁇ css/ ⁇ cs ⁇ 0.90 with respect to the cord diameter ⁇ cs [mm] of the cord. This has the advantage of realizing the strong Tcs of the carcass layer 13 described above.
- the carcass layer 13 is formed by laminating a pair of carcass plies 13A and 13B (see FIG. 9). Further, a pair of carcass plies 13A and 13B are constructed by covering a carcass cord 13cc made of an organic fiber material with a coat rubber 13cr. Further, the cord diameter ⁇ cs [mm] (dimension symbol in the figure is omitted) of the carcass cord 13cc is in the range of 0.60 ⁇ cs ⁇ 0.90. Further, the driving number Ecs [pieces/50 mm] of the carcass cord 13cc is in the range of 40 ⁇ Ecs ⁇ 70. This has the advantage of realizing the strong Tcs of the carcass layer 13 described above.
- the total gauge Gu [mm] of the tire side portion at the point Au on the side profile is The outer diameter OD [mm] is in the range of 0.010 ⁇ Gu/OD ⁇ 0.080.
- the above lower limit ensures the total gauge Gu of the radially outer region of the tire side portion, suppresses tire deformation during use under high load, and ensures tire durability.
- small-diameter tires are expected to be used under high internal pressure and high loads, so the above-mentioned tire durability performance can be significantly achieved.
- the above upper limit suppresses deterioration of the rolling resistance of the tire due to the total gauge Gu becoming excessively large.
- FIGS. 13 to 15 are charts showing the results of performance tests on tires according to embodiments of the present invention.
- test tires were evaluated regarding (1) durability performance and (2) low rolling resistance performance (fuel consumption rate). Further, as an example of a small diameter tire, test tires of two types of tire sizes are used. Specifically, [A] a test tire with a tire size of 145/80R12 was assembled on a rim with a rim size of 12 x 4.00B, and [B] a test tire with a tire size of 235/45R10 was assembled on a rim with a rim size of 10. It will be done.
- the test tires 1 to 29 of the examples were particularly equipped with the structures shown in FIGS. 1 to 3 and 8, and included a pair of bead cores 11, 11, a carcass layer 13 consisting of a single carcass ply, and a pair of crossed belts. 141, 142, a belt layer 14 consisting of a belt cover 143 and a pair of belt edge covers 144, 144, tread rubber 15, sidewall rubber 16 and rim cushion rubber 17.
- the tire outer diameter OD was 531 [mm]
- the tire total width SW and the tire cross-sectional width DW were 143 [mm]
- the tire cross-sectional height SH was 123 [mm].
- the inner diameter of the tire is 305 [mm].
- the inner liner 18 is made of a rubber composition containing butyl rubber as a main component or a thermoplastic resin.
- the test tire of the comparative example was the same as the test tire of Example 1, but the distance TLu [mm] from the center of the carcass cord 13cc of the innermost layer 13A of the carcass ply to the inner surface of the tire in the region from point Iu to point Ic (see FIG. 12) ) is set small.
- test tires of Examples achieve both tire durability performance and low rolling resistance performance.
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Abstract
In a cross-section of the tire 1 along the tire meridian direction, a point on a side profile located at the same tire-radial-direction position as an end of the innermost layer 141 of belt layers 14 is referred to as point Au. The foot of a perpendicular from point Au to a carcass layer 13 is referred to as point Iu, and the foot of a perpendicular from a tire-maximum-width position Ac to the carcass layer is referred to as point Ic. The carcass layer 13 comprises one or more carcass plies obtained by coating carcass cords 13cc with a coating rubber 13cr. In the region ranging from point Iu to point Ic, the distance TLu [mm] between the center of the carcass cords 13cc of the innermost carcass ply 13A and the inner surface of the tire, with respect to the tire outer diameter OD [mm], is in the range of 0.00010≤TLu/OD≤0.01500.
Description
この発明は、タイヤに関し、さらに詳しくは、タイヤの耐久性能および低転がり抵抗性能を両立できるタイヤに関する。
The present invention relates to a tire, and more particularly to a tire that can achieve both tire durability and low rolling resistance.
近年では、床面を低くして車内スペースを拡張した車両に装着される、小径タイヤが開発されている。かかる小径タイヤでは、回転慣性が小さくタイヤ重量も小さいため、輸送コストの低減が期待される。一方で、小径タイヤには、高い負荷能力が要求される。このような課題に関する従来のタイヤとして、特許文献1に記載される技術が知られている。
In recent years, small-diameter tires have been developed to be installed on vehicles with lower floor surfaces and expanded interior space. Such small-diameter tires have low rotational inertia and low tire weight, and are expected to reduce transportation costs. On the other hand, small diameter tires are required to have high load capacity. As a conventional tire related to such a problem, a technique described in Patent Document 1 is known.
この発明は、タイヤの耐久性能および低転がり抵抗性能を両立できるタイヤを提供することを目的とする。
An object of the present invention is to provide a tire that can achieve both tire durability and low rolling resistance.
上記目的を達成するため、この発明にかかるタイヤは、一対のビードコアと、前記ビードコアに架け渡されたカーカス層と、前記カーカス層の径方向外側に配置されたベルト層と、カーカス層の内面に配置されたインナーライナとを備え、タイヤ外径OD[mm]が、200≦OD≦660の範囲にあり、タイヤ総幅SW[mm]が、100≦SW≦400の範囲にあり、タイヤ子午線方向の断面視にて、前記ベルト層の最内層の端部に対してタイヤ径方向の同位置にあるサイドプロファイル上の点Auを定義し、点Auから前記カーカス層に下した垂線の足を点Iuとして定義し、タイヤ最大幅位置Acから前記カーカス層に下した垂線の足を点Icとして定義し、前記カーカス層が、カーカスコードをコートゴムで被覆して成る単一層あるいは複数層のカーカスプライから構成され、且つ、点Iuから点Icまでの領域における前記カーカスプライの最内層の前記カーカスコードの中心からタイヤ内面までの距離TLu[mm]が、タイヤ外径OD[mm]に対して0.00010≦TLu/OD≦0.01500の範囲にあることを特徴とする。
In order to achieve the above object, a tire according to the present invention includes a pair of bead cores, a carcass layer spanning the bead cores, a belt layer disposed on the radially outer side of the carcass layer, and an inner surface of the carcass layer. The tire outer diameter OD [mm] is in the range of 200≦OD≦660, the tire total width SW [mm] is in the range of 100≦SW≦400, and the tire meridian direction is In the cross-sectional view, define a point Au on the side profile at the same position in the tire radial direction with respect to the end of the innermost layer of the belt layer, and define the foot of the perpendicular line drawn from point Au to the carcass layer as a point. The foot of the perpendicular line drawn from the tire maximum width position Ac to the carcass layer is defined as the point Ic, and the carcass layer is made of a single layer or multiple layers of carcass ply consisting of a carcass cord coated with rubber. The distance TLu [mm] from the center of the carcass cord of the innermost layer of the carcass ply to the inner surface of the tire in the region from point Iu to point Ic is 0. It is characterized by being in the range of 00010≦TLu/OD≦0.01500.
この発明にかかるタイヤでは、ベルト層の端部からタイヤ最大幅位置までの領域におけるカーカス層からタイヤ内面までの距離が適正化される利点がある。具体的に、上記下限により、エア漏れが発生し易い上記領域におけるカーカス層からタイヤ内面までの距離TLuが確保されて、エア漏れに起因するタイヤの耐久性能の低下や転がり抵抗の悪化が抑制される。また、上記上限により、タイヤ重量の増加に起因する転がり抵抗の悪化が抑制される。これにより、タイヤの耐久性能および低転がり抵抗性能が両立する。特に小径タイヤでは、上記した高内圧および高負荷で使用されるため、応力集中が起きやすい傾向にある。したがって、上記構成が小径タイヤに採用されることで、タイヤの耐久性能および低転がり抵抗性能の向上作用が顕著に得られる。
The tire according to the present invention has the advantage that the distance from the carcass layer to the inner surface of the tire in the region from the end of the belt layer to the tire maximum width position is optimized. Specifically, the above lower limit ensures the distance TLu from the carcass layer to the inner surface of the tire in the above region where air leaks are likely to occur, and suppresses a decrease in tire durability performance and worsening of rolling resistance due to air leaks. Ru. Further, the above upper limit suppresses deterioration of rolling resistance due to an increase in tire weight. This achieves both tire durability and low rolling resistance. In particular, small-diameter tires are used under the above-mentioned high internal pressure and high load, so stress concentration tends to occur easily. Therefore, when the above configuration is adopted for a small diameter tire, the durability performance and low rolling resistance performance of the tire can be significantly improved.
以下、この発明につき図面を参照しつつ詳細に説明する。なお、この実施の形態によりこの発明が限定されるものではない。また、この実施の形態の構成要素には、発明の同一性を維持しつつ置換可能かつ置換自明なものが含まれる。また、この実施の形態に記載された複数の変形例は、当業者自明の範囲内にて任意に組み合わせが可能である。
Hereinafter, this invention will be explained in detail with reference to the drawings. Note that the present invention is not limited to this embodiment. Further, the constituent elements of this embodiment include elements that can be replaced while maintaining the identity of the invention and are obvious to be replaced. Further, the plurality of modifications described in this embodiment can be arbitrarily combined within the range obvious to those skilled in the art.
[タイヤ]
図1は、この発明の実施の形態にかかるタイヤ1を示すタイヤ子午線方向の断面図である。同図は、リム10に装着されたタイヤ1のタイヤ径方向の片側領域の断面図を示している。この実施の形態では、タイヤの一例として、乗用車用空気入りラジアルタイヤについて説明する。 [tire]
FIG. 1 is a cross-sectional view in the tire meridian direction showing atire 1 according to an embodiment of the present invention. This figure shows a cross-sectional view of one side area in the tire radial direction of the tire 1 mounted on the rim 10. In this embodiment, a pneumatic radial tire for a passenger car will be described as an example of a tire.
図1は、この発明の実施の形態にかかるタイヤ1を示すタイヤ子午線方向の断面図である。同図は、リム10に装着されたタイヤ1のタイヤ径方向の片側領域の断面図を示している。この実施の形態では、タイヤの一例として、乗用車用空気入りラジアルタイヤについて説明する。 [tire]
FIG. 1 is a cross-sectional view in the tire meridian direction showing a
同図において、タイヤ子午線方向の断面は、タイヤ回転軸(図示省略)を含む平面でタイヤを切断したときの断面として定義される。また、タイヤ赤道面CLは、JATMAに規定されたタイヤ断面幅DWの中点を通りタイヤ回転軸に垂直な平面として定義される。また、タイヤ幅方向は、タイヤ回転軸に平行な方向として定義され、タイヤ径方向は、タイヤ回転軸に垂直な方向として定義される。また、点Tは、タイヤ接地端であり、点Acは、タイヤ最大幅位置である。
In the figure, a cross section in the tire meridian direction is defined as a cross section when the tire is cut along a plane that includes the tire rotation axis (not shown). Further, the tire equatorial plane CL is defined as a plane that passes through the midpoint of the tire cross-sectional width DW defined in JATMA and is perpendicular to the tire rotation axis. Further, the tire width direction is defined as a direction parallel to the tire rotation axis, and the tire radial direction is defined as a direction perpendicular to the tire rotation axis. Further, point T is the tire ground contact edge, and point Ac is the tire maximum width position.
タイヤ1は、タイヤ回転軸を中心とする環状構造を有し、一対のビードコア11、11と、一対のビードフィラー12、12と、カーカス層13と、ベルト層14と、トレッドゴム15と、一対のサイドウォールゴム16、16と、一対のリムクッションゴム17、17と、インナーライナ18とを備える(図1参照)。
The tire 1 has an annular structure centered around the tire rotation axis, and includes a pair of bead cores 11, 11, a pair of bead fillers 12, 12, a carcass layer 13, a belt layer 14, a tread rubber 15, and a pair of bead cores 11, 11, a pair of bead fillers 12, 12, a carcass layer 13, a belt layer 14, a tread rubber 15, sidewall rubber 16, 16, a pair of rim cushion rubber 17, 17, and an inner liner 18 (see FIG. 1).
一対のビードコア11、11は、スチールから成る1本あるいは複数本のビードワイヤを環状かつ多重に巻き廻して成り、ビード部に埋設されて左右のビード部のコアを構成する。一対のビードフィラー12、12は、一対のビードコア11、11のタイヤ径方向外周にそれぞれ配置されてビード部を補強する。また、ビードフィラー12が、55以上105以下のゴム硬さHs_bf、2.0以上13.0以下の100[%]伸長時のモジュラスM_bf[MPa]および0.03以上0.30以下の損失正接tanδ_bfを有し、好ましくは70以上100以下のゴム硬さHs_bf、3.0以上12.0以下の100[%]伸長時のモジュラスM_bf[MPa]および0.05以上0.25以下の損失正接tanδ_bfを有する。
The pair of bead cores 11, 11 are formed by winding one or more bead wires made of steel in an annular shape and multiple times, and are embedded in the bead portions to form the cores of the left and right bead portions. The pair of bead fillers 12, 12 are arranged on the outer peripheries of the pair of bead cores 11, 11 in the tire radial direction, respectively, to reinforce the bead portions. In addition, the bead filler 12 has a rubber hardness Hs_bf of 55 or more and 105 or less, a modulus at 100 [%] elongation M_bf [MPa] of 2.0 or more and 13.0 or less, and a loss tangent of 0.03 or more and 0.30 or less. tan δ_bf, preferably a rubber hardness Hs_bf of 70 or more and 100 or less, a modulus M_bf [MPa] at elongation of 100 [%] of 3.0 or more and 12.0 or less, and a loss tangent of 0.05 or more and 0.25 or less. It has tanδ_bf.
カーカス層13は、1枚のカーカスプライから成る単層構造あるいは複数枚のカーカスプライを積層して成る多層構造を有し、左右のビードコア11、11間にトロイダル状に架け渡されてタイヤの骨格を構成する。また、カーカス層13の両端部は、ビードコア11およびビードフィラー12を包み込むようにタイヤ幅方向外側に巻き返されて係止される。また、カーカス層13のカーカスプライは、無機繊維(例えば、スチール、カーボンファイバー、グラスファイバー)あるいは有機繊維材(例えば、アラミド、ナイロン、ポリエステル、レーヨンなど)から成る複数のカーカスコードをコートゴムで被覆して圧延加工して構成され、80[deg]以上100[deg]以下のコード角度(タイヤ周方向に対するカーカスコードの長手方向の傾斜角として定義される。)を有する。
The carcass layer 13 has a single layer structure consisting of one carcass ply or a multilayer structure consisting of a plurality of carcass plies laminated, and is spanned in a toroidal shape between the left and right bead cores 11, 11, and is the frame of the tire. Configure. Further, both ends of the carcass layer 13 are wound back and locked outward in the tire width direction so as to wrap around the bead core 11 and bead filler 12. Further, the carcass ply of the carcass layer 13 is formed by covering a plurality of carcass cords made of inorganic fibers (e.g., steel, carbon fiber, glass fiber) or organic fibers (e.g., aramid, nylon, polyester, rayon, etc.) with coated rubber. The cord angle (defined as the inclination angle in the longitudinal direction of the carcass cord with respect to the tire circumferential direction) is 80 [deg] or more and 100 [deg] or less.
ベルト層14は、複数のベルトプライ141~144を積層して成り、カーカス層13の外周に掛け廻されて配置される。図1の構成では、ベルトプライ141~144が、一対の交差ベルト141、142と、ベルトカバー143および一対のベルトエッジカバー144、144とから構成される。
The belt layer 14 is formed by laminating a plurality of belt plies 141 to 144, and is arranged to be wrapped around the outer periphery of the carcass layer 13. In the configuration of FIG. 1, belt plies 141 to 144 are composed of a pair of intersecting belts 141, 142, a belt cover 143, and a pair of belt edge covers 144, 144.
一対の交差ベルト141、142は、スチールあるいは有機繊維材から成る複数のベルトコードをコートゴムで被覆して圧延加工して構成され、絶対値で15[deg]以上55[deg]以下のコード角度(タイヤ周方向に対するベルトコードの長手方向の傾斜角として定義される。)を有する。また、一対の交差ベルト141、142は、相互に異符号のコード角度を有し、ベルトコードの長手方向を相互に交差させて積層される(いわゆるクロスプライ構造)。また、一対の交差ベルト141、142は、カーカス層13のタイヤ径方向外側に積層されて配置される。
The pair of crossed belts 141 and 142 are constructed by rolling a plurality of belt cords made of steel or organic fibers coated with rubber, and have a cord angle of 15 [deg] or more and 55 [deg] or less in absolute value ( ) is defined as the inclination angle of the belt cord in the longitudinal direction with respect to the tire circumferential direction. Further, the pair of crossed belts 141 and 142 have cord angles of opposite signs and are laminated with the longitudinal directions of the belt cords crossing each other (so-called cross-ply structure). Further, the pair of crossing belts 141 and 142 are stacked and arranged on the outside of the carcass layer 13 in the tire radial direction.
ベルトカバー143および一対のベルトエッジカバー144、144は、スチールあるいは有機繊維材から成るベルトカバーコードをコートゴムで被覆して構成され、絶対値で0[deg]以上10[deg]以下のコード角度を有する。また、ベルトカバー143およびベルトエッジカバー144は、例えば、1本あるいは複数本のベルトカバーコードをコートゴムで被覆して成るストリップ材であり、このストリップ材を交差ベルト141、142の外周面に対してタイヤ周方向に複数回かつ螺旋状に巻き付けて構成される。また、ベルトカバー143が交差ベルト141、142の全域を覆って配置され、一対のベルトエッジカバー144、144が交差ベルト141、142の左右のエッジ部をタイヤ径方向外側から覆って配置される。
The belt cover 143 and the pair of belt edge covers 144, 144 are constructed by covering a belt cover cord made of steel or organic fiber material with coated rubber, and have a cord angle of 0 [deg] or more and 10 [deg] or less in absolute value. have The belt cover 143 and the belt edge cover 144 are, for example, strip materials made by covering one or more belt cover cords with coated rubber, and these strip materials are applied to the outer peripheral surfaces of the crossed belts 141 and 142. It is constructed by wrapping it spirally multiple times in the circumferential direction of the tire. Further, a belt cover 143 is arranged to cover the entire area of the crossing belts 141, 142, and a pair of belt edge covers 144, 144 are arranged to cover the left and right edge portions of the crossing belts 141, 142 from the outside in the tire radial direction.
トレッドゴム15は、カーカス層13およびベルト層14のタイヤ径方向外周に配置されてタイヤ1のトレッド部を構成する。また、トレッドゴム15は、キャップトレッド151と、アンダートレッド152とを備える。
The tread rubber 15 is arranged on the outer periphery of the carcass layer 13 and the belt layer 14 in the tire radial direction, and constitutes the tread portion of the tire 1. Further, the tread rubber 15 includes a cap tread 151 and an undertread 152.
キャップトレッド151は、接地特性および耐候性に優れるゴム材料から成り、タイヤ接地面の全域に渡ってトレッド面に露出して、トレッド部の外表面を構成する。また、キャップトレッド151が、50以上80以下のゴム硬さHs_cap、1.0以上4.0以下の100[%]伸長時のモジュラスM_cap[MPa]および0.03以上0.36以下の損失正接tanδ_capを有し、好ましくは58以上76以下のゴム硬さHs_cap、1.5以上3.2以下の100[%]伸長時のモジュラスM_cap[MPa]および0.06以上0.29以下の損失正接tanδ_capを有する。
The cap tread 151 is made of a rubber material with excellent ground contact characteristics and weather resistance, and is exposed on the tread surface over the entire tire contact area and constitutes the outer surface of the tread portion. In addition, the cap tread 151 has a rubber hardness Hs_cap of 50 or more and 80 or less, a modulus M_cap [MPa] at 100 [%] elongation of 1.0 or more and 4.0 or less, and a loss tangent of 0.03 or more and 0.36 or less. tan δ_cap, preferably rubber hardness Hs_cap of 58 or more and 76 or less, modulus at 100 [%] elongation M_cap [MPa] of 1.5 or more and 3.2 or less, and loss tangent of 0.06 or more and 0.29 or less. It has tanδ_cap.
ゴム硬さHsは、JIS K6253に準拠した20[℃]の温度条件にて測定される。
Rubber hardness Hs is measured at a temperature of 20 [° C.] in accordance with JIS K6253.
モジュラス(破断強度)は、JIS K6251(3号ダンベル使用)に準拠して、ダンベル状試験片を用いた温度20[℃]での引張試験により測定される。
The modulus (breaking strength) is measured by a tensile test at a temperature of 20 [° C.] using a dumbbell-shaped test piece in accordance with JIS K6251 (using a No. 3 dumbbell).
損失正接tanδは、(株)東洋精機製作所製の粘弾性スペクトロメーターを用いて、温度60[℃]、剪断歪み10[%]、振幅±0.5[%]および周波数20[Hz]の条件で測定される。
The loss tangent tan δ was determined using a viscoelastic spectrometer manufactured by Toyo Seiki Seisakusho Co., Ltd. under the conditions of temperature 60 [℃], shear strain 10 [%], amplitude ±0.5 [%], and frequency 20 [Hz]. It is measured in
アンダートレッド152は、耐熱性に優れるゴム材料から成り、キャップトレッド151とベルト層14との間に挟み込まれて配置されて、トレッドゴム15のベース部分を構成する。また、アンダートレッド152が、47以上80以下のゴム硬さHs_ut、1.4以上5.5以下の100[%]伸長時のモジュラスM_ut[MPa]および0.02以上0.23以下の損失正接tanδ_utを有し、好ましくは50以上65以下のゴム硬さHs_ut、1.7以上3.5以下の100[%]伸長時のモジュラスM_ut[MPa]および0.03以上0.10以下の損失正接tanδ_utを有する。
The undertread 152 is made of a rubber material with excellent heat resistance, is sandwiched between the cap tread 151 and the belt layer 14, and forms the base portion of the tread rubber 15. In addition, the undertread 152 has a rubber hardness Hs_ut of 47 or more and 80 or less, a modulus at 100 [%] elongation M_ut [MPa] of 1.4 or more and 5.5 or less, and a loss tangent of 0.02 or more and 0.23 or less. tan δ_ut, preferably a rubber hardness Hs_ut of 50 or more and 65 or less, a modulus at 100 [%] elongation M_ut [MPa] of 1.7 or more and 3.5 or less, and a loss tangent of 0.03 or more and 0.10 or less. It has tan δ_ut.
また、ゴム硬さの差Hs_cap-Hs_utが3以上20以下の範囲にあり、好ましくは5以上15以下の範囲にある。また、モジュラスの差M_cap-M_ut[MPa]が0以上1.4以下の範囲にあり、好ましくは0.1以上1.0以下の範囲にある。また、損失正接の差tanδ_cap-tanδ_utが0以上0.22以下の範囲にあり、好ましくは0.02以上0.16以下の範囲にある。
Furthermore, the difference in rubber hardness Hs_cap−Hs_ut is in the range of 3 or more and 20 or less, preferably in the range of 5 or more and 15 or less. Further, the modulus difference M_cap−M_ut [MPa] is in the range of 0 or more and 1.4 or less, preferably 0.1 or more and 1.0 or less. Further, the loss tangent difference tanδ_cap−tanδ_ut is in the range of 0 or more and 0.22 or less, preferably 0.02 or more and 0.16 or less.
一対のサイドウォールゴム16、16は、カーカス層13のタイヤ幅方向外側にそれぞれ配置されて左右のサイドウォール部を構成する。図1の構成では、サイドウォールゴム16のタイヤ径方向外側の端部が、トレッドゴム15の下層に配置されてベルト層14の端部とカーカス層13との間に挟み込まれている。しかし、これに限らず、サイドウォールゴム16のタイヤ径方向外側の端部が、トレッドゴム15の外層に配置されてタイヤのバットレス部に露出しても良い(図示省略)。この場合には、ベルトクッション(図示省略)が、ベルト層14の端部とカーカス層13との間に挟み込まれる。
A pair of sidewall rubbers 16, 16 are respectively arranged on the outside of the carcass layer 13 in the tire width direction, and constitute left and right sidewall portions. In the configuration of FIG. 1, the outer end of the sidewall rubber 16 in the tire radial direction is disposed below the tread rubber 15 and is sandwiched between the end of the belt layer 14 and the carcass layer 13. However, the present invention is not limited thereto, and the outer end of the sidewall rubber 16 in the tire radial direction may be disposed on the outer layer of the tread rubber 15 and exposed to the buttress portion of the tire (not shown). In this case, a belt cushion (not shown) is sandwiched between the end of the belt layer 14 and the carcass layer 13.
また、サイドウォールゴム16が、48以上65以下のゴム硬さHs_sw、1.0以上2.4以下の100[%]伸長時のモジュラスM_sw[MPa]および0.02以上0.22以下の損失正接tanδ_swを有し、好ましくは50以上59以下のゴム硬さHs_sw、1.2以上2.2以下の100[%]伸長時のモジュラスM_sw[MPa]および0.04以上0.20以下の損失正接tanδ_swを有する。
In addition, the sidewall rubber 16 has a rubber hardness Hs_sw of 48 or more and 65 or less, a modulus M_sw [MPa] at 100 [%] elongation of 1.0 or more and 2.4 or less, and a loss of 0.02 or more and 0.22 or less. It has a tangent tan δ_sw, preferably a rubber hardness Hs_sw of 50 or more and 59 or less, a modulus M_sw [MPa] at 100 [%] elongation of 1.2 or more and 2.2 or less, and a loss of 0.04 or more and 0.20 or less. It has a tangent tan δ_sw.
一対のリムクッションゴム17、17は、左右のビードコア11、11およびカーカス層13の巻き返し部のタイヤ径方向内側からタイヤ幅方向外側に延在して、ビード部のリム嵌合面を構成する。図1の構成では、リムクッションゴム17のタイヤ径方向外側の端部が、サイドウォールゴム16の下層に挿入されて、サイドウォールゴム16とカーカス層13との間に挟み込まれて配置されている。また、リムクッションゴム17が、60以上80以下のゴム硬さHs_rc、2.0以上7.0以下の100[%]伸長時のモジュラスM_rc[MPa]および0.09以上0.35以下の損失正接tanδ_rcを有し、好ましくは65以上75以下のゴム硬さHs_rc、3.0以上6.0以下の100[%]伸長時のモジュラスM_rc[MPa]および0.11以上0.30以下の損失正接tanδ_rcを有する。
A pair of rim cushion rubbers 17, 17 extend from the inner side in the tire radial direction to the outer side in the tire width direction of the left and right bead cores 11, 11 and the rolled-up portion of the carcass layer 13, and constitute a rim fitting surface of the bead portion. In the configuration shown in FIG. 1, the outer end of the rim cushion rubber 17 in the tire radial direction is inserted into the lower layer of the sidewall rubber 16, and is sandwiched between the sidewall rubber 16 and the carcass layer 13. . In addition, the rim cushion rubber 17 has a rubber hardness Hs_rc of 60 or more and 80 or less, a modulus M_rc [MPa] at 100 [%] elongation of 2.0 or more and 7.0 or less, and a loss of 0.09 or more and 0.35 or less. It has a tangent tanδ_rc, preferably a rubber hardness Hs_rc of 65 or more and 75 or less, a modulus M_rc [MPa] at 100 [%] elongation of 3.0 or more and 6.0 or less, and a loss of 0.11 or more and 0.30 or less. It has a tangent tanδ_rc.
インナーライナ18は、タイヤ内腔面に配置されてカーカス層13を覆う空気透過防止層であり、カーカス層13の露出による酸化を抑制し、また、タイヤに充填された空気の洩れを防止する。また、インナーライナ18は、例えば、ブチルゴムを主成分とするゴム組成物で構成されても良いし、熱可塑性樹脂あるいは熱可塑性樹脂中にエラストマー成分をブレンドした熱可塑性エラストマー組成物などから構成されても良い。
The inner liner 18 is an air permeation prevention layer placed on the inner cavity surface of the tire and covering the carcass layer 13, and suppresses oxidation due to exposure of the carcass layer 13, and also prevents air filled in the tire from leaking. In addition, the inner liner 18 may be made of, for example, a rubber composition containing butyl rubber as a main component, or may be made of a thermoplastic resin or a thermoplastic elastomer composition obtained by blending an elastomer component into a thermoplastic resin. Also good.
また、図1において、タイヤ外径OD[mm]が、200≦OD≦660の範囲にあり、好ましくは、250[mm]≦OD≦580[mm]の範囲にある。かかる小径のタイヤを適用対象とすることにより、後述する負荷性能の向上効果が顕著に得られる。また、タイヤ総幅SW[mm]が、100≦SW≦400の範囲にあり、好ましくは105[mm]≦SW≦340[mm]の範囲にある。かかる小径のタイヤ1では、例えば、小型車両の床面を低くして車内スペースを拡張できる。また、回転慣性が小さくタイヤ重量も小さいため、燃費が向上して輸送コストが低減される。特に車両のインホイールモータに装着された場合に、モータへの負荷が効果的に低減される。
Further, in FIG. 1, the tire outer diameter OD [mm] is in the range of 200≦OD≦660, preferably in the range of 250 [mm]≦OD≦580 [mm]. By applying the present invention to such small-diameter tires, the effect of improving load performance, which will be described later, can be significantly achieved. Further, the tire total width SW [mm] is in the range of 100≦SW≦400, preferably in the range of 105 [mm]≦SW≦340 [mm]. With such a small diameter tire 1, for example, the floor surface of a small vehicle can be lowered to expand the interior space of the vehicle. Furthermore, since the rotational inertia is small and the tire weight is small, fuel efficiency is improved and transportation costs are reduced. Particularly when attached to an in-wheel motor of a vehicle, the load on the motor is effectively reduced.
タイヤ外径ODは、タイヤを規定リムに装着して規定内圧を付与すると共に無負荷状態として測定される。
The tire outer diameter OD is measured while the tire is mounted on a specified rim, a specified internal pressure is applied, and the tire is in an unloaded state.
タイヤ総幅SWは、タイヤを規定リムに装着して規定内圧を付与すると共に無負荷状態としたときのサイドウォール間の(タイヤ側面の模様、文字などのすべての部分を含む)直線距離として測定される。
Tire total width SW is measured as the straight line distance between the sidewalls (including all parts such as the pattern on the side of the tire, letters, etc.) when the tire is mounted on the specified rim, the specified internal pressure is applied, and no load is applied. be done.
規定リムとは、JATMAに規定される「適用リム」、TRAに規定される「Design Rim」、あるいはETRTOに規定される「Measuring Rim」をいう。また、規定内圧とは、JATMAに規定される「最高空気圧」、TRAに規定される「TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES」の最大値、あるいはETRTOに規定される「INFLATION PRESSURES」をいう。また、規定荷重とは、JATMAに規定される「最大負荷能力」、TRAに規定される「TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES」の最大値、あるいはETRTOに規定される「LOAD CAPACITY」をいう。ただし、JATMAにおいて、乗用車用タイヤの場合には、規定内圧が空気圧180[kPa]であり、規定荷重が最大負荷能力の88[%]である。
The specified rim refers to the "applicable rim" specified in JATMA, the "Design Rim" specified in TRA, or the "Measuring Rim" specified in ETRTO. In addition, the specified internal pressure refers to the "maximum air pressure" specified in JATMA, the maximum value of "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" specified in TRA, or "INFLATION PRESSURES" specified in ETRTO. In addition, the specified load refers to the "maximum load capacity" specified in JATMA, the maximum value of "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" specified in TRA, or "LOAD CAPACITY" specified in ETRTO. However, in JATMA, for passenger car tires, the specified internal pressure is 180 [kPa], and the specified load is 88 [%] of the maximum load capacity.
また、タイヤ総幅SW[mm]が、タイヤ外径OD[mm]に対して0.23≦SW/OD≦0.84の範囲にあり、好ましくは0.25≦SW/OD≦0.81の範囲にある。
Further, the total tire width SW [mm] is in the range of 0.23≦SW/OD≦0.84 with respect to the tire outer diameter OD [mm], preferably 0.25≦SW/OD≦0.81. within the range of
また、タイヤ外径ODとタイヤ総幅SWとが、以下の数式(1)を満たすことが好ましい。ここで、A1min=-0.0017、A2min=0.9、A3min=130、A1max=-0.0019、A2max=1.4、A3max=400であり、好ましくはA1min=-0.0018、A2min=0.9、A3min=160、A1max=-0.0024、A2max=1.6、A3max=362である。
Furthermore, it is preferable that the tire outer diameter OD and the tire total width SW satisfy the following formula (1). Here, A1min=-0.0017, A2min=0.9, A3min=130, A1max=-0.0019, A2max=1.4, A3max=400, preferably A1min=-0.0018, A2min= 0.9, A3min=160, A1max=-0.0024, A2max=1.6, and A3max=362.
上記タイヤ1では、5[inch]以上16[inch]以下(すなわち125[mm]以上407[mm]以下)のリム径を有するリム10の使用が想定される。また、リム径RD[mm]が、タイヤ外径OD[mm]に対して0.50≦RD/OD≦0.74の範囲にあり、好ましくは0.52≦RD/OD≦0.71の範囲にある。上記下限により、リム径RDが確保されて、特にインホイールモータの設置スペースを確保できる。上記上限により、後述するタイヤの内容積Vが確保されて、タイヤの負荷能力が確保される。
In the tire 1 described above, it is assumed that a rim 10 having a rim diameter of 5 [inch] or more and 16 [inch] or less (that is, 125 [mm] or more and 407 [mm] or less) is used. Further, the rim diameter RD [mm] is in the range of 0.50≦RD/OD≦0.74 with respect to the tire outer diameter OD [mm], preferably 0.52≦RD/OD≦0.71. in range. With the above lower limit, the rim diameter RD can be secured, and especially the installation space for the in-wheel motor can be secured. With the above upper limit, the inner volume V of the tire, which will be described later, is ensured, and the load capacity of the tire is ensured.
なお、タイヤ内径は、リム10のリム径RDに等しい。
Note that the tire inner diameter is equal to the rim diameter RD of the rim 10.
また、上記タイヤ1は、規定よりも高い内圧、具体的には350[kPa]以上1200[kPa]以下、好ましくは500[kPa]以上1000[kPa]以下の内圧での使用が想定される。上記下限により、タイヤの転がり抵抗が効果的に低減され、上記上限により、内圧充填作業の安全性が確保される。
Furthermore, the tire 1 is expected to be used at an internal pressure higher than the regulation, specifically at an internal pressure of 350 [kPa] or more and 1200 [kPa] or less, preferably 500 [kPa] or more and 1000 [kPa] or less. The lower limit effectively reduces the rolling resistance of the tire, and the upper limit ensures the safety of the internal pressure filling operation.
また、上記タイヤ1は、例えば小型シャトルバスのような、低速で走行する車両に装着されることが想定される。また、車両の最高速度が100[km/h]以下であり、好ましくは80[km/h]以下であり、より好ましくは60[km/h]以下である。また、上記タイヤ1は、6~12輪の車両に装着されることが想定される。これにより、タイヤの負荷能力が適正に発揮される。
Furthermore, it is assumed that the tire 1 is mounted on a vehicle that travels at low speed, such as a small shuttle bus, for example. Further, the maximum speed of the vehicle is 100 [km/h] or less, preferably 80 [km/h] or less, and more preferably 60 [km/h] or less. Further, it is assumed that the tire 1 is mounted on a vehicle with 6 to 12 wheels. Thereby, the load capacity of the tire is properly exhibited.
また、タイヤの偏平比、すなわちタイヤ断面高さSH[mm](後述する図2参照)とタイヤ断面幅DW[mm]との比SH/DWが、0.16≦SH/DW≦0.85の範囲にあり、好ましくは0.19≦SH/DW≦0.82の範囲にある。
Further, the aspect ratio of the tire, that is, the ratio SH/DW of the tire cross-sectional height SH [mm] (see FIG. 2 described later) and the tire cross-sectional width DW [mm] is 0.16≦SH/DW≦0.85. It is preferably in the range of 0.19≦SH/DW≦0.82.
タイヤ断面高さSHは、タイヤ外径とリム径との差の1/2の距離であり、タイヤを規定リムに装着して規定内圧を付与すると共に無負荷状態として測定される。
The tire cross-sectional height SH is a distance that is 1/2 of the difference between the tire outer diameter and the rim diameter, and is measured with the tire mounted on a specified rim, a specified internal pressure applied, and an unloaded state.
タイヤ断面幅DWは、タイヤを規定リムに装着して規定内圧を付与すると共に無負荷状態としたときのサイドウォール間の(タイヤ側面の模様、文字などを除いた)直線距離として測定される。
The tire cross-sectional width DW is measured as the straight-line distance between the sidewalls (excluding patterns, letters, etc. on the side surface of the tire) when the tire is mounted on a specified rim, a specified internal pressure is applied, and the tire is in an unloaded state.
また、タイヤ接地幅TWが、タイヤ総幅SWに対して0.50≦TW/SW≦0.85の範囲にあり、好ましくは0.60≦TW/SW≦0.80の範囲にある。
Further, the tire ground contact width TW is in the range of 0.50≦TW/SW≦0.85 with respect to the tire total width SW, preferably in the range of 0.60≦TW/SW≦0.80.
タイヤ接地幅TWは、タイヤを規定リムに装着して規定内圧を付与すると共に静止状態にて平板に対して垂直に置いて規定荷重に対応する負荷を付与したときのタイヤと平板との接触面におけるタイヤ軸方向の最大直線距離として測定される。
Tire contact width TW is the contact surface between the tire and the flat plate when the tire is mounted on a specified rim, a specified internal pressure is applied, and the tire is placed perpendicular to the flat plate in a stationary state and a load corresponding to the specified load is applied. measured as the maximum straight line distance in the axial direction of the tire.
また、タイヤ内容積V[m^3]が、タイヤ外径OD[mm]に対して4.0≦(V/OD)×10^6≦60の範囲にあり、好ましくは6.0≦(V/OD)×10^6≦50の範囲にある。これにより、タイヤ内容積Vが適正化される。具体的に、上記下限により、タイヤ内容積が確保されて、タイヤの負荷能力が確保される。特に小径タイヤでは、高内圧および高負荷での使用が想定されるため、タイヤ内容積Vが十分に確保されることが好ましい。上記上限により、タイヤ内容積Vが過大となることに起因するタイヤの大型化が抑制される。
Further, the tire internal volume V [m^3] is in the range of 4.0≦(V/OD)×10^6≦60 with respect to the tire outer diameter OD [mm], preferably 6.0≦( V/OD)×10^6≦50. Thereby, the tire internal volume V is optimized. Specifically, the above lower limit ensures the inner volume of the tire and the load capacity of the tire. In particular, small-diameter tires are expected to be used under high internal pressure and high load, so it is preferable that the tire internal volume V is sufficiently secured. The above upper limit suppresses the tire from increasing in size due to the tire internal volume V becoming excessively large.
また、タイヤ内容積V[m^3]が、リム径RD[mm]に対して0.5≦V×RD≦17の範囲にあり、好ましくは1.0≦V×RD≦15の範囲にある。
Further, the tire internal volume V [m^3] is in the range of 0.5≦V×RD≦17 with respect to the rim diameter RD [mm], preferably in the range of 1.0≦V×RD≦15. be.
[ビードコアおよびビードフィラー]
図1において、上記のように、一対のビードコア11、11がスチールから成る1本あるいは複数本のビードワイヤ(図示省略)を環状かつ多重に巻き廻して成る。また、一対のビードフィラー12、12が一対のビードコア11、11のタイヤ径方向外周にそれぞれ配置される。 [Bead core and bead filler]
In FIG. 1, as described above, a pair of bead cores 11, 11 are formed by winding one or more bead wires (not shown) made of steel in an annular manner and in multiple layers. Further, a pair of bead fillers 12, 12 are arranged on the outer peripheries of the pair of bead cores 11, 11 in the tire radial direction, respectively.
図1において、上記のように、一対のビードコア11、11がスチールから成る1本あるいは複数本のビードワイヤ(図示省略)を環状かつ多重に巻き廻して成る。また、一対のビードフィラー12、12が一対のビードコア11、11のタイヤ径方向外周にそれぞれ配置される。 [Bead core and bead filler]
In FIG. 1, as described above, a pair of
また、1つのビードコア11の強力Tbd[N]が、タイヤ外径OD[mm]に対して45≦Tbd/OD≦120の範囲にあり、好ましくは50≦Tbd/OD≦110の範囲にあり、より好ましくは60≦Tbd/OD≦105の範囲にある。また、ビードコアの強力Tbd[N]が、タイヤ総幅SW[mm]に対して90≦Tbd/SW≦400の範囲にあり、好ましくは110≦Tbd/SW≦350の範囲にある。これにより、ビードコア11の負荷能力が適正に確保される。具体的に、上記下限により、高負荷での使用時におけるタイヤ変形が抑制されて、タイヤの耐久性能が確保される。また、高内圧での使用が可能となり、タイヤの転がり抵抗が低減される。特に小径タイヤでは、高内圧および高負荷での使用が想定されるため、上記したタイヤの耐久性能および転がり抵抗の低減作用が顕著に得られる。上記上限により、ビードコアの質量増加に起因する転がり抵抗の悪化が抑制される。
Further, the strength Tbd [N] of one bead core 11 is in the range of 45≦Tbd/OD≦120 with respect to the tire outer diameter OD [mm], preferably in the range of 50≦Tbd/OD≦110, More preferably, the range is 60≦Tbd/OD≦105. Further, the strength Tbd [N] of the bead core is in the range of 90≦Tbd/SW≦400, preferably in the range of 110≦Tbd/SW≦350 with respect to the tire total width SW [mm]. Thereby, the load capacity of the bead core 11 is appropriately ensured. Specifically, the above lower limit suppresses tire deformation during use under high loads and ensures tire durability. In addition, it becomes possible to use the tire at high internal pressure, and the rolling resistance of the tire is reduced. In particular, small-diameter tires are expected to be used under high internal pressure and high loads, so the above-described tire durability and rolling resistance reduction effect can be significantly achieved. The above upper limit suppresses deterioration of rolling resistance due to an increase in the mass of the bead core.
ビードコア11の強力Tbd[N]は、ビードワイヤ1本あたりの強力[N/本]と径方向断面視におけるビードワイヤの総本数[本]との積として算出される。ビードワイヤの強力は、JIS K1017に準拠した温度20[℃]での引張試験により測定される。
The strength Tbd [N] of the bead core 11 is calculated as the product of the strength per bead wire [N/piece] and the total number of bead wires [pieces] in a radial cross-sectional view. The strength of the bead wire is measured by a tensile test at a temperature of 20 [° C.] in accordance with JIS K1017.
また、ビードコア11の強力Tbd[N]が、タイヤ外径OD[mm]、距離SWD[mm]およびリム径RD[mm]に対して以下の数式(2)を満たすことが好ましい。ここで、B1min=0.26、B2min=10.0、B1max=2.5、B2max=99.0であり、好ましくはB1min=0.35、B2min=14.0、B1max=2.5、B2max=99.0であり、より好ましくはB1min=0.44、B2min=17.6、B1max=2.5、B2max=99.0であり、さらに好ましくはB1min=0.49、B2min=17.9、B1max=2.5、B2max=99.0である。さらに、タイヤの規定内圧P[kPa]を用いて、B1min=0.0016×P、B2min=0.07×Pであることが好ましい。
Furthermore, it is preferable that the strength Tbd [N] of the bead core 11 satisfies the following formula (2) with respect to the tire outer diameter OD [mm], the distance SWD [mm], and the rim diameter RD [mm]. Here, B1min=0.26, B2min=10.0, B1max=2.5, B2max=99.0, preferably B1min=0.35, B2min=14.0, B1max=2.5, B2max =99.0, more preferably B1min=0.44, B2min=17.6, B1max=2.5, B2max=99.0, even more preferably B1min=0.49, B2min=17.9 , B1max=2.5, B2max=99.0. Further, it is preferable that B1min=0.0016×P and B2min=0.07×P using the specified internal pressure P [kPa] of the tire.
距離SWDは、タイヤ回転軸(図示省略)からタイヤ最大幅位置Acまでの径方向距離の2倍の距離、すなわちタイヤ最大幅位置Acの直径であり、タイヤを規定リムに装着して規定内圧を付与すると共に無負荷状態として測定される。
The distance SWD is twice the radial distance from the tire rotation axis (not shown) to the tire maximum width position Ac, that is, the diameter of the tire maximum width position Ac. It is measured as an unloaded state when applied.
タイヤ最大幅位置Acは、JATMAに規定されるタイヤ断面幅DWの最大幅位置として定義される。
The tire maximum width position Ac is defined as the maximum width position of the tire cross-sectional width DW specified by JATMA.
また、1つのビードコア11の径方向断面視にて、上記したスチールから成るビードワイヤの総断面積σbd[mm^2]が、タイヤ外径OD[mm]に対して0.025≦σbd/OD≦0.075の範囲にあり、好ましくは0.030≦σbd/OD≦0.065の範囲にある。また、ビードワイヤの総断面積σbd[mm^2]が、11≦σbd≦36の範囲にあり、好ましくは13≦σbd≦33の範囲にある。これにより、上記したビードコア11の強力Tbd[N]が実現される。
In addition, in a radial cross-sectional view of one bead core 11, the total cross-sectional area σbd [mm^2] of the bead wire made of steel described above is 0.025≦σbd/OD≦ with respect to the tire outer diameter OD [mm]. It is in the range of 0.075, preferably in the range of 0.030≦σbd/OD≦0.065. Further, the total cross-sectional area σbd [mm^2] of the bead wire is in the range of 11≦σbd≦36, preferably in the range of 13≦σbd≦33. Thereby, the strong Tbd[N] of the bead core 11 described above is realized.
ビードワイヤの総断面積σbd[mm^2]は、1つのビードコア11の径方向断面視におけるビードワイヤの断面積の総和として算出される。
The total cross-sectional area σbd [mm^2] of the bead wire is calculated as the sum of the cross-sectional areas of the bead wire in a radial cross-sectional view of one bead core 11.
例えば、図1の構成では、ビードコア11が、円形断面を有するビードワイヤ(図示省略)を格子状に配列して成る四角形を有している。しかし、これに限らず、ビードコア11が、円形断面を有するビードワイヤを最密充填構造にて配列して成る六角形を有しても良い(図示省略)。その他、当業者自明の範囲内にて、任意のビードワイヤの配列構造を採用できる。
For example, in the configuration shown in FIG. 1, the bead core 11 has a rectangular shape formed by arranging bead wires (not shown) having a circular cross section in a grid pattern. However, the present invention is not limited to this, and the bead core 11 may have a hexagonal shape formed by arranging bead wires having a circular cross section in a close-packed structure (not shown). In addition, any bead wire arrangement structure can be adopted within the range obvious to those skilled in the art.
また、ビードワイヤの総断面積σbd[mm^2]が、タイヤ外径OD[mm]、距離SWD[mm]およびリム径RD[mm]に対して以下の数式(3)を満たすことが好ましい。ここで、Cmin=30、Cmax=8であり、好ましくはCmin=25、Cmax=10である。
Further, it is preferable that the total cross-sectional area σbd [mm^2] of the bead wire satisfies the following formula (3) with respect to the tire outer diameter OD [mm], the distance SWD [mm], and the rim diameter RD [mm]. Here, Cmin=30 and Cmax=8, preferably Cmin=25 and Cmax=10.
また、ビードワイヤの総断面積σbd[mm^2]が、径方向断面視における1つのビードコア11のビードワイヤの総断面数(すなわち総巻き数)Nbd[本]に対して0.50≦σbd/Nbd≦1.40の範囲にあり、好ましくは0.60≦σbd/Nbd≦1.20範囲にある。すなわち、単体のビードワイヤの断面積σbd’[mm^2]が、0.50[mm^2/本]以上1.40[mm^2/本]以下の範囲にあり、好ましくは0.60[mm^2/本]以上1.20[mm^2/本]以下の範囲にある。
Further, the total cross-sectional area σbd [mm^2] of the bead wire is 0.50≦σbd/Nbd with respect to the total number of cross-sections (that is, the total number of turns) Nbd [pieces] of the bead wire of one bead core 11 in a radial cross-sectional view. It is in the range of ≦1.40, preferably in the range of 0.60≦σbd/Nbd≦1.20. That is, the cross-sectional area σbd' [mm^2] of a single bead wire is in the range of 0.50 [mm^2/piece] to 1.40 [mm^2/piece], preferably 0.60 [mm^2/piece]. mm^2/piece] or more and 1.20 [mm^2/piece] or less.
また、径方向断面視における1つのビードコア11の最大幅Wbd[mm](後述する図2参照)が、ビードワイヤの総断面積σbd[mm^2]に対して0.16≦Wbd/σbd≦0.50の範囲にあり、好ましくは0.20≦Wbd/σbd≦0.40の範囲にある。
Further, the maximum width Wbd [mm] of one bead core 11 in a radial cross-sectional view (see FIG. 2 described later) is 0.16≦Wbd/σbd≦0 with respect to the total cross-sectional area σbd [mm^2] of the bead wire. .50, preferably 0.20≦Wbd/σbd≦0.40.
また、図1において、一対のビードコア11、11の重心間の距離Dbd[mm]が、タイヤ総幅SW[mm]に対して0.63≦Dbd/SW≦0.97の範囲にあり、好ましくは0.65≦Dbd/SW≦0.95の範囲にある。上記下限により、タイヤの撓み量が低減されて、タイヤの転がり抵抗が低減される。上記上限により、タイヤサイド部に作用する応力が低減されて、タイヤ故障が抑制される。
Further, in FIG. 1, the distance Dbd [mm] between the centers of gravity of the pair of bead cores 11, 11 is preferably in the range of 0.63≦Dbd/SW≦0.97 with respect to the tire total width SW [mm]. is in the range of 0.65≦Dbd/SW≦0.95. With the above lower limit, the amount of tire deflection is reduced, and the rolling resistance of the tire is reduced. The above upper limit reduces the stress acting on the tire side portion, thereby suppressing tire failure.
また、図2において、ビードコア11の径方向外側の端部からビードフィラー23の径方向外側の端部までの径方向距離BH[mm]、すなわちビードフィラー23の高さが、タイヤ断面高さSH[mm]に対して0.10≦BH/SH≦0.40の範囲にあり、好ましくは0.15≦BH/SH≦0.35の範囲にある。
In addition, in FIG. 2, the radial distance BH [mm] from the radially outer end of the bead core 11 to the radially outer end of the bead filler 23, that is, the height of the bead filler 23 is equal to the tire cross-sectional height SH [mm] is in the range of 0.10≦BH/SH≦0.40, preferably in the range of 0.15≦BH/SH≦0.35.
径方向距離BH[mm]は、タイヤを規定リムに装着して規定内圧を付与すると共に無負荷状態として測定される。
The radial distance BH [mm] is measured with the tire mounted on a specified rim, a specified internal pressure applied, and an unloaded state.
[カーカス層]
図2は、図1に記載したタイヤ1を示す拡大図である。同図は、タイヤ赤道面CLを境界とした片側領域を示している。 [Carcass layer]
FIG. 2 is an enlarged view showing thetire 1 shown in FIG. The figure shows a region on one side with the tire equatorial plane CL as a boundary.
図2は、図1に記載したタイヤ1を示す拡大図である。同図は、タイヤ赤道面CLを境界とした片側領域を示している。 [Carcass layer]
FIG. 2 is an enlarged view showing the
図1の構成では、上記のように、カーカス層13が、単層のカーカスプライから成り、左右のビードコア11、11間にトロイダル状に架け渡されて配置される。また、カーカス層13の両端部が、ビードコア11およびビードフィラー12を包み込むようにタイヤ幅方向外側に巻き返されて係止される。
In the configuration of FIG. 1, as described above, the carcass layer 13 is composed of a single layer of carcass ply, and is arranged in a toroidal manner between the left and right bead cores 11, 11. Further, both ends of the carcass layer 13 are rolled back and locked outward in the tire width direction so as to wrap around the bead core 11 and bead filler 12.
また、カーカス層13を構成するカーカスプライの幅50[mm]あたりの強力Tcs[N/50mm]が、タイヤ外径OD[mm]に対して17≦Tcs/OD≦120の範囲にあり、好ましくは20≦Tcs/OD≦120の範囲にある。また、カーカス層13の強力Tcs[N/50mm]が、タイヤ総幅SW[mm]に対して30≦Tcs/SW≦260の範囲にあり、好ましくは35≦Tcs/SW≦220の範囲にある。かかる構成では、小径タイヤにおいてカーカス層13の負荷能力が適正に確保されるので、タイヤの耐久性能および低転がり抵抗性能が両立する利点がある。具体的に、上記下限により、高負荷での使用時におけるタイヤ変形が抑制されて、タイヤの耐久性能が確保される。また、高内圧での使用が可能となり、タイヤの転がり抵抗が低減される。特に小径タイヤでは、高内圧および高負荷での使用が想定されるため、上記したタイヤの耐久性能および転がり抵抗の低減作用が顕著に得られる。上記上限により、カーカス層の質量増加に起因する転がり抵抗の悪化が抑制される。
Further, the strength Tcs [N/50mm] per width 50 [mm] of the carcass ply constituting the carcass layer 13 is preferably in the range of 17≦Tcs/OD≦120 with respect to the tire outer diameter OD [mm]. is in the range of 20≦Tcs/OD≦120. Further, the strength Tcs [N/50mm] of the carcass layer 13 is in the range of 30≦Tcs/SW≦260 with respect to the tire total width SW [mm], preferably in the range of 35≦Tcs/SW≦220. . In such a configuration, since the load capacity of the carcass layer 13 is appropriately ensured in a small-diameter tire, there is an advantage that the tire has both durability performance and low rolling resistance performance. Specifically, the above lower limit suppresses tire deformation during use under high loads and ensures tire durability. In addition, it becomes possible to use the tire at high internal pressure, and the rolling resistance of the tire is reduced. In particular, small-diameter tires are expected to be used under high internal pressure and high loads, so the above-described tire durability and rolling resistance reduction effect can be significantly achieved. The above upper limit suppresses deterioration of rolling resistance due to increase in mass of the carcass layer.
カーカスプライの強力Tcs[N/50mm]は、以下のように算出される。すなわち、左右のビードコア11、11に架け渡されてタイヤ内周の全域に渡って延在するカーカスプライを、有効カーカスプライとして定義する。そして、有効カーカスプライを構成するカーカスコード1本あたりの強力[N/本]とタイヤ全周かつタイヤ赤道面CL上における幅50[mm]あたりのカーカスコードの打ち込み本数[本/50mm]との積が、カーカスプライの強力Tcs[N/50mm]として算出される。カーカスコードの強力は、JIS K1017に準拠した温度20[℃]での引張試験により測定される。例えば、1本のカーカスコードが例えば複数の素線を撚り合わせて成る構成では、撚り合わされた1本のカーカスコードの強力が計測されて、カーカス層13の強力Tcsが算出される。また、カーカス層13が複数の有効カーカスプライを積層して成る多層構造(図示省略)を有する構成では、複数の有効カーカスプライのそれぞれについて上記した強力Tcsが定義される。
The strength Tcs [N/50mm] of the carcass ply is calculated as follows. That is, the carcass ply that spans the left and right bead cores 11 and extends over the entire inner circumference of the tire is defined as an effective carcass ply. Then, the strength per carcass cord [N/piece] that constitutes an effective carcass ply and the number of carcass cords driven per width 50 [mm] around the entire circumference of the tire and on the tire equatorial plane CL [pieces/50mm] The product is calculated as the carcass ply strength Tcs [N/50mm]. The strength of the carcass cord is measured by a tensile test at a temperature of 20 [° C.] in accordance with JIS K1017. For example, in a configuration in which one carcass cord is formed by twisting a plurality of wires together, the strength of one twisted carcass cord is measured, and the strength Tcs of the carcass layer 13 is calculated. Further, in a configuration in which the carcass layer 13 has a multilayer structure (not shown) formed by laminating a plurality of effective carcass plies, the above-mentioned strength Tcs is defined for each of the plurality of effective carcass plies.
例えば、図1の構成では、カーカス層13が単一のカーカスプライ(図中の符号省略)から成る単層構造を有し、また、カーカスプライが、コートゴムで被覆されたスチールから成るカーカスコードをタイヤ周方向に対して80[deg]以上100[deg]以下のコード角度で配列して構成されている(図示省略)。また、上記したスチールから成るカーカスコードが、0.15≦φcs≦1.10の範囲、好ましくは0.25≦φcs≦0.60の範囲にあるコード径φcs[mm]および25≦Ecs≦80の範囲、好ましくは50≦Ecs≦80の範囲にある打ち込み本数Ecs[本/50mm]を有することにより、上記したカーカス層13の強力Tcs[N/50mm]が実現される。また、カーカスコードが複数の素線を撚り合わせて成り、且つ、その素線径φcss[mm]が0.12≦φcss≦0.24の範囲にあり、好ましくは0.14≦φcss≦0.22の範囲にある。また、カーカスコードの素線径φcss[mm]が、カーカスコードのコード径φcs[mm]に対して0.30≦φcss/φcs≦0.90の範囲にあると更に好ましい。なお、カーカスコードが、スチール以外の無機繊維(例えば、カーボンファイバー、グラスファイバーなど)から構成されても良い。
For example, in the configuration shown in FIG. 1, the carcass layer 13 has a single layer structure consisting of a single carcass ply (number omitted in the figure), and the carcass ply has a carcass cord made of steel covered with coated rubber. The cords are arranged at a cord angle of 80 [deg] or more and 100 [deg] or less with respect to the tire circumferential direction (not shown). Further, the carcass cord made of steel described above has a cord diameter φcs [mm] in a range of 0.15≦φcs≦1.10, preferably in a range of 0.25≦φcs≦0.60, and a cord diameter φcs [mm] in a range of 25≦Ecs≦80. By having the driving number Ecs [pieces/50mm] in the range of , preferably in the range of 50≦Ecs≦80, the above-described strength Tcs [N/50mm] of the carcass layer 13 is realized. Further, the carcass cord is formed by twisting a plurality of wires, and the wire diameter φcss [mm] is in the range of 0.12≦φcss≦0.24, preferably 0.14≦φcss≦0. It is in the range of 22. Further, it is more preferable that the wire diameter φcss [mm] of the carcass cord is in the range of 0.30≦φcss/φcs≦0.90 with respect to the cord diameter φcs [mm] of the carcass cord. Note that the carcass cord may be made of inorganic fibers other than steel (eg, carbon fiber, glass fiber, etc.).
また、上記に限らず、カーカスプライが、コートゴムで被覆された有機繊維材(例えば、アラミド、ナイロン、ポリエステル、レーヨンなど)から成るカーカスコードにより構成されても良い。この場合には、上記有機繊維材から成るカーカスコードが、0.60≦φcs≦0.90の範囲にあるコード径φcs[mm]および40≦Ecs≦70の範囲にある打ち込み本数Ecs[本/50mm]を有することにより、上記したカーカス層13の強力Tcs[N/50mm]が実現される。その他、高強力なナイロン、アラミド、ハイブリッドなどの有機繊維材から成るカーカスコードを当業者自明の範囲内で採用できる。
Furthermore, the present invention is not limited to the above, and the carcass ply may be constituted by a carcass cord made of an organic fiber material (for example, aramid, nylon, polyester, rayon, etc.) coated with coated rubber. In this case, the carcass cord made of the above-mentioned organic fiber material has a cord diameter φcs [mm] in the range of 0.60≦φcs≦0.90 and a driving number Ecs [pieces/cord] in the range 40≦Ecs≦70. 50 mm], the above-described strong Tcs of the carcass layer 13 [N/50 mm] is realized. In addition, carcass cords made of high-strength organic fiber materials such as nylon, aramid, and hybrid can be employed within the range obvious to those skilled in the art.
また、カーカス層13が、複数、例えば2層のカーカスプライを積層して成る多層構造を有しても良い(図示省略)。これにより、タイヤの負荷能力を効果的に高め得る。
Furthermore, the carcass layer 13 may have a multilayer structure formed by laminating a plurality of carcass plies, for example, two layers (not shown). Thereby, the load capacity of the tire can be effectively increased.
また、カーカス層13の総強力TTcs[N]が、タイヤ外径OD[mm]に対して300≦TTcs/OD≦3500の範囲にあり、好ましくは400≦TTcs/OD≦3000の範囲にある。これにより、カーカス層13の全体の負荷能力が確保される。
Further, the total strength TTcs [N] of the carcass layer 13 is in the range of 300≦TTcs/OD≦3500, preferably in the range of 400≦TTcs/OD≦3000 with respect to the tire outer diameter OD [mm]. This ensures the entire load capacity of the carcass layer 13.
カーカス層13の総強力TTcs[N]は、カーカスコード1本あたりの強力[N/本]とカーカス層13の全体におけるカーカスコードの打ち込み本数[本]の総数との積として算出される。このため、カーカス層13の総強力TTcs[N]は、各カーカスプライの強力Tcs[N/50mm]、カーカスプライの積層枚数、カーカスプライの周長などの増加に伴って増加する。
The total strength TTcs [N] of the carcass layer 13 is calculated as the product of the strength per carcass cord [N/cord] and the total number of carcass cords driven into the entire carcass layer 13 [number]. Therefore, the total strength TTcs [N] of the carcass layer 13 increases as the strength Tcs [N/50 mm] of each carcass ply, the number of laminated carcass plies, the circumference of the carcass ply, etc. increase.
また、カーカス層13の総強力TTcs[N]が、タイヤ外径OD[mm]および距離SWD[mm]に対して以下の数式(4)を満たすことが好ましい。ここで、Dmin=2.2、Dmax=40であり、好ましくはDmin=4.3、Dmax=40であり、より好ましくはDmin=6.5、Dmax=40であり、さらに好ましくはDmin=8.7、Dmax=40である。さらに、タイヤの規定内圧P[kPa]を用いて、Dmin=0.02×Pであることが好ましい。
Further, it is preferable that the total strength TTcs [N] of the carcass layer 13 satisfies the following formula (4) with respect to the tire outer diameter OD [mm] and the distance SWD [mm]. Here, Dmin=2.2, Dmax=40, preferably Dmin=4.3, Dmax=40, more preferably Dmin=6.5, Dmax=40, still more preferably Dmin=8 .7, Dmax=40. Further, it is preferable that Dmin=0.02×P using the specified tire internal pressure P [kPa].
また、図1の構成では、カーカス層13が、タイヤ内面に沿って延在する本体部131と、ビードコア11を包み込むようにタイヤ幅方向外側に巻きあげられてタイヤ径方向に延在する巻き上げ部132とを有する。また、図2において、リム径RDの測定点からカーカス層13の巻き上げ部132の端部までの径方向高さHcs[mm]が、タイヤ断面高さSH[mm]に対して0.10≦Hcs/SH≦0.49の範囲にあり、好ましくは0.15≦Hcs/SH≦0.47の範囲にある。これにより、カーカス層13の巻き上げ部132の径方向高さHcsが適正化される。具体的に、上記下限により、タイヤサイド部の負荷能力が確保され、上記上限により、カーカス層の質量増加に起因する転がり抵抗の悪化が抑制される。
In addition, in the configuration of FIG. 1, the carcass layer 13 includes a main body portion 131 extending along the inner surface of the tire, and a rolled-up portion extending in the tire radial direction that is rolled up outward in the tire width direction so as to wrap around the bead core 11. 132. In addition, in FIG. 2, the radial height Hcs [mm] from the measurement point of the rim diameter RD to the end of the rolled-up portion 132 of the carcass layer 13 is 0.10≦ with respect to the tire cross-sectional height SH [mm]. Hcs/SH≦0.49, preferably 0.15≦Hcs/SH≦0.47. Thereby, the radial height Hcs of the rolled up portion 132 of the carcass layer 13 is optimized. Specifically, the lower limit ensures the load capacity of the tire side portion, and the upper limit suppresses deterioration in rolling resistance due to an increase in the mass of the carcass layer.
カーカス層13の巻き上げ部132の径方向高さHcs[mm]は、タイヤを規定リムに装着して規定内圧を付与すると共に無負荷状態として測定される。
The radial height Hcs [mm] of the rolled-up portion 132 of the carcass layer 13 is measured with the tire mounted on a specified rim, a specified internal pressure applied, and an unloaded state.
例えば、図2の構成では、カーカス層13の巻き上げ部132の径方向外側の端部(図中の符号省略)が、タイヤ最大幅位置Acよりもタイヤ径方向内側の領域にあり、より具体的にはタイヤ最大幅位置Acから後述する距離Hlの70[%]の径方向位置Al’まで領域内にある。このとき、カーカス層13の本体部131と巻き上げ部132との接触高さHcs’[mm]が、タイヤ断面高さSH[mm]に対して0.07≦Hcs’/SHの範囲にあり、好ましくは0.10≦Hcs’/SHの範囲にある。これにより、タイヤサイド部の負荷能力が効果的に高まる。比Hcs’/SHの上限は、特に限定がないが、接触高さHcs’がカーカス層13の巻き上げ部132の径方向高さHcsに対してHcs’<Hcsの関係を有することにより制約を受ける。
For example, in the configuration of FIG. 2, the radially outer end (number omitted in the figure) of the rolled-up portion 132 of the carcass layer 13 is located in a region radially inward of the tire maximum width position Ac. is within the range from the tire maximum width position Ac to a radial position Al' that is 70% of the distance Hl, which will be described later. At this time, the contact height Hcs' [mm] between the main body part 131 and the rolled-up part 132 of the carcass layer 13 is in the range of 0.07≦Hcs'/SH with respect to the tire cross-sectional height SH [mm], It is preferably in the range of 0.10≦Hcs'/SH. This effectively increases the load capacity of the tire side portion. The upper limit of the ratio Hcs'/SH is not particularly limited, but is limited by the fact that the contact height Hcs' has a relationship of Hcs'<Hcs with respect to the radial height Hcs of the rolled up portion 132 of the carcass layer 13. .
カーカス層13の接触高さHcs’は、本体部131と巻き上げ部132とが相互に接触する領域のタイヤ径方向の延在長さであり、タイヤを規定リムに装着して規定内圧を付与すると共に無負荷状態として測定される。
The contact height Hcs' of the carcass layer 13 is the extension length in the tire radial direction of the region where the main body part 131 and the rolled-up part 132 contact each other, and when the tire is mounted on a specified rim and a specified internal pressure is applied. and is measured as a no-load condition.
なお、上記に限らず、カーカス層13がいわゆるハイターンナップ構造を有することにより、カーカス層13の巻き上げ部132の端部が、タイヤ最大幅位置Acよりもタイヤ径方向外側の領域に配置されても良い(図示省略)。
Note that this is not limited to the above, and because the carcass layer 13 has a so-called high turn-up structure, even if the end of the rolled-up portion 132 of the carcass layer 13 is arranged in a region outside the tire maximum width position Ac in the tire radial direction. Good (not shown).
[ベルト層]
図3は、図1に記載したタイヤ1のベルト層の積層構造を示す説明図である。同図では、各ベルトプライ141~144に付された細線が、ベルトコードの配置構成を模式的に示している。 [Belt layer]
FIG. 3 is an explanatory diagram showing the laminated structure of the belt layers of thetire 1 shown in FIG. 1. In the figure, thin lines attached to each belt ply 141 to 144 schematically show the arrangement of the belt cords.
図3は、図1に記載したタイヤ1のベルト層の積層構造を示す説明図である。同図では、各ベルトプライ141~144に付された細線が、ベルトコードの配置構成を模式的に示している。 [Belt layer]
FIG. 3 is an explanatory diagram showing the laminated structure of the belt layers of the
図1の構成では、上記のように、ベルト層14が、複数のベルトプライ141~144を積層して成る。また、図3に示すように、これらのベルトプライ141~144が、一対の交差ベルト141、142と、ベルトカバー143および一対のベルトエッジカバー144、144とから構成される。
In the configuration of FIG. 1, as described above, the belt layer 14 is formed by laminating a plurality of belt plies 141 to 144. Further, as shown in FIG. 3, these belt plies 141 to 144 are composed of a pair of crossed belts 141, 142, a belt cover 143, and a pair of belt edge covers 144, 144.
このとき、一対の交差ベルト141、142のそれぞれの幅50[mm]あたりの強力Tbt[N/50mm]が、タイヤ外径OD[mm]に対して25≦Tbt/OD≦250の範囲にあり、好ましくは30≦Tbt/OD≦230の範囲にある。また、交差ベルト141、142の強力Tbt[N/50mm]が、タイヤ総幅SW[mm]に対して45≦Tbt/SW≦500の範囲にあり、好ましくは50≦Tbt/SW≦450の範囲にある。これにより、一対の交差ベルト141、142のそれぞれの負荷能力が適正に確保される。具体的に、上記下限により、高負荷での使用時におけるタイヤ変形が抑制されて、タイヤの耐久性能が確保される。また、高内圧での使用が可能となり、タイヤの転がり抵抗が低減される。特に小径タイヤでは、高内圧および高負荷での使用が想定されるため、上記したタイヤの耐久性能および転がり抵抗の低減作用が顕著に得られる。上記上限により、交差ベルトの質量増加に起因する転がり抵抗の悪化が抑制される。
At this time, the strength Tbt [N/50 mm] per width 50 [mm] of each of the pair of crossed belts 141 and 142 is in the range of 25≦Tbt/OD≦250 with respect to the tire outer diameter OD [mm]. , preferably in the range of 30≦Tbt/OD≦230. Further, the strength Tbt [N/50mm] of the crossing belts 141 and 142 is in the range of 45≦Tbt/SW≦500 with respect to the tire total width SW [mm], preferably in the range of 50≦Tbt/SW≦450. It is in. Thereby, the load capacity of each of the pair of crossing belts 141 and 142 is appropriately ensured. Specifically, the above lower limit suppresses tire deformation during use under high loads and ensures tire durability. In addition, it becomes possible to use the tire at high internal pressure, and the rolling resistance of the tire is reduced. In particular, small-diameter tires are expected to be used under high internal pressure and high loads, so the above-described tire durability and rolling resistance reduction effect can be significantly achieved. The above upper limit suppresses deterioration of rolling resistance due to an increase in the mass of the intersecting belt.
ベルトプライの強力Tbt[N/50mm]は、以下のように算出される。すなわち、タイヤ赤道面CLを中心とするタイヤ接地幅TWの80[%]の領域(すなわちタイヤ接地領域の中央部)の全域に渡って延在するベルトプライを、有効ベルトプライとして定義する。そして、有効ベルトプライを構成するベルトコード1本あたりの強力[N/本]と上記したタイヤ接地幅TWの80[%]の領域における幅50[mm]あたりのベルトコードの打ち込み本数[本]との積が、ベルトプライの強力Tbt[N/50mm]として算出される。ベルトコードの強力は、JIS K1017に準拠した温度20[℃]での引張試験により測定される。例えば、1本のベルトコードが例えば複数の素線を撚り合わせて成る構成では、撚り合わされた1本のベルトコードの強力が計測されて、ベルトプライの強力Tbtが算出される。また、ベルト層14が複数の有効ベルトプライを積層して成る構成(図1参照)では、複数の有効ベルトプライのそれぞれについて上記した強力Tbtが定義される。例えば、図1の構成では、一対の交差ベルト141、142およびベルトカバー143が有効ベルトプライに該当する。
The strength Tbt [N/50mm] of the belt ply is calculated as follows. That is, the belt ply extending over the entire area of 80% of the tire ground contact width TW centered on the tire equatorial plane CL (that is, the central part of the tire ground contact area) is defined as an effective belt ply. Then, the strength [N/piece] per belt cord constituting the effective belt ply and the number of belt cords driven per width 50 [mm] in the area of 80 [%] of the tire ground contact width TW described above [pieces] The product is calculated as the belt ply strength Tbt [N/50mm]. The strength of the belt cord is measured by a tensile test at a temperature of 20 [° C.] in accordance with JIS K1017. For example, in a configuration in which one belt cord is formed by twisting a plurality of wires together, the strength of the one twisted belt cord is measured, and the strength Tbt of the belt ply is calculated. Further, in a structure in which the belt layer 14 is formed by laminating a plurality of effective belt plies (see FIG. 1), the above-mentioned strength Tbt is defined for each of the plurality of effective belt plies. For example, in the configuration of FIG. 1, a pair of intersecting belts 141 and 142 and a belt cover 143 correspond to the effective belt ply.
例えば、図3の構成では、一対の交差ベルト141、142が、コートゴムで被覆されたスチール製のベルトコードをタイヤ周方向に対して15[deg]以上55[deg]以下のコード角度(図中の寸法記号省略)で配列して構成されている。また、上記スチール製のベルトコードが、0.50≦φbt≦1.80の範囲にあるコード径φbt[mm]および15≦Ebt≦75の範囲にある打ち込み本数Ebt[本/50mm]を有することにより、上記交差ベルト141、142の強力Tbt[N/50mm]が実現される。また、コード径φbt[mm]および打ち込み本数Ebt[本/50mm]は、0.55≦φbt≦1.60および17≦Ebt≦50の範囲にあることが好ましく、0.60≦φbt≦1.30および20≦Ebt≦40の範囲にあることがより好ましい。また、ベルトコードが複数の素線を撚り合わせて成り、且つ、その素線径φbts[mm]が0.16≦φbts≦0.43の範囲にあり、好ましくは0.21≦φbts≦0.39の範囲にある。
For example, in the configuration shown in FIG. 3, a pair of crossed belts 141 and 142 extend a steel belt cord covered with coated rubber at a cord angle of 15 degrees or more and 55 degrees or less (in the figure) with respect to the tire circumferential direction. (dimension symbol omitted). In addition, the above-mentioned steel belt cord has a cord diameter φbt [mm] in the range of 0.50≦φbt≦1.80 and a number of inserted cords Ebt [pieces/50 mm] in the range of 15≦Ebt≦75. As a result, a strong Tbt [N/50 mm] of the crossing belts 141 and 142 is realized. Further, the cord diameter φbt [mm] and the driving number Ebt [pieces/50 mm] are preferably in the ranges of 0.55≦φbt≦1.60 and 17≦Ebt≦50, and 0.60≦φbt≦1. It is more preferable to be in the range of 30 and 20≦Ebt≦40. Further, the belt cord is formed by twisting a plurality of wires, and the wire diameter φbts [mm] is in the range of 0.16≦φbts≦0.43, preferably 0.21≦φbts≦0. It is in the range of 39.
また、上記に限らず、交差ベルト141、142が、コートゴムで被覆された有機繊維材(例えば、アラミド、ナイロン、ポリエステル、レーヨンなど)から成るベルトコードにより構成されても良い。この場合には、上記有機繊維材から成るベルトコードが、0.50≦φbt≦0.90の範囲にあるコード径φbt[mm]および30≦Ebt≦65の範囲にある打ち込み本数Ebt[本/50mm]を有することにより、上記した交差ベルト141、142の強力Tbt[N/50mm]が実現される。また、高強力なナイロン、アラミド、ハイブリッドなどの有機繊維材から成るベルトコードを当業者自明の範囲内で採用できる。
Furthermore, the present invention is not limited to the above, and the crossed belts 141 and 142 may be constituted by belt cords made of an organic fiber material (for example, aramid, nylon, polyester, rayon, etc.) coated with coated rubber. In this case, the belt cord made of the organic fiber material has a cord diameter φbt [mm] in the range of 0.50≦φbt≦0.90 and a number of cords Ebt [cords/cord] in the range 30≦Ebt≦65. 50 mm], the above-mentioned strong force Tbt [N/50 mm] of the crossing belts 141 and 142 is realized. Further, a belt cord made of a highly strong organic fiber material such as nylon, aramid, or hybrid can be employed within the range obvious to those skilled in the art.
また、ベルト層14が、付加ベルト(図示省略)を有しても良い。かかる付加ベルトは、例えば、(1)第三の交差ベルトであり、スチールあるいは有機繊維材から成る複数のベルトコードをコートゴムで被覆して圧延加工して構成され、絶対値で15[deg]以上55[deg]以下のコード角度を有し、または、(2)いわゆる高角度ベルトであり、スチールあるいは有機繊維材から成る複数のベルトコードをコートゴムで被覆して圧延加工して構成され、絶対値で45[deg]以上70[deg]以下、好ましくは、54[deg]以上68[deg]以下のコード角度を有し得る。また、付加ベルトが、(a)一対の交差ベルト141、142とカーカス層13との間、(b)一対の交差ベルト141、142の間、または、(c)一対の交差ベルト141、142の径方向外側に配置され得る(図示省略)。これにより、ベルト層14の負荷能力が向上する。
Additionally, the belt layer 14 may include an additional belt (not shown). Such an additional belt is, for example, (1) a third cross belt, which is constructed by covering a plurality of belt cords made of steel or organic fiber material with coated rubber and rolling them, and has an absolute value of 15 [deg] or more. It has a cord angle of 55[deg] or less, or (2) it is a so-called high-angle belt, which is constructed by rolling a plurality of belt cords made of steel or organic fiber material and coated with rubber, and the absolute value The cord angle may be 45 [deg] or more and 70 [deg] or less, preferably 54 [deg] or more and 68 [deg] or less. Further, the additional belt is located between (a) the pair of crossed belts 141, 142 and the carcass layer 13, (b) between the pair of crossed belts 141, 142, or (c) between the pair of crossed belts 141, 142. It may be arranged radially outward (not shown). This improves the load capacity of the belt layer 14.
また、ベルト層14の総強力TTbt[N]が、タイヤ外径OD[mm]に対して70≦TTbt/OD≦750の範囲にあり、好ましくは90≦TTbt/OD≦690の範囲にあり、より好ましくは110≦TTbt/OD≦690の範囲にあり、さらに好ましくは120≦TTbt/OD≦690の範囲にある。これにより、ベルト層14の全体の負荷能力が確保される。さらに、タイヤの規定内圧P[kPa]を用いて、0.16×P≦TTbt/ODであることが好ましい。
Further, the total strength TTbt [N] of the belt layer 14 is in the range of 70≦TTbt/OD≦750 with respect to the tire outer diameter OD [mm], preferably in the range of 90≦TTbt/OD≦690, More preferably, the range is 110≦TTbt/OD≦690, and even more preferably, the range is 120≦TTbt/OD≦690. This ensures the entire load capacity of the belt layer 14. Furthermore, using the specified internal pressure P [kPa] of the tire, it is preferable that 0.16×P≦TTbt/OD.
ベルト層14の総強力TTbt[N]は、ベルトコード1本あたりの強力[N/本]とベルト層14の全体におけるベルトコードの打ち込み本数[本]の総数との積として算出される。このため、ベルト層14の総強力TTbt[N]は、各ベルトプライの強力Tbt[N/50mm]、ベルトプライの積層枚数などの増加に伴って増加する。
The total strength TTbt [N] of the belt layer 14 is calculated as the product of the strength per belt cord [N/cord] and the total number of belt cords driven in the entire belt layer 14 [number]. Therefore, the total strength TTbt [N] of the belt layer 14 increases as the strength Tbt [N/50 mm] of each belt ply, the number of laminated belt plies, etc. increase.
また、一対の交差ベルト141、142(上記した付加ベルトを備える構成では、付加ベルトを含む。図示省略)のうち最も幅広な交差ベルト(図3では、内径側の交差ベルト141)の幅Wb1[mm]が、最も幅狭な交差ベルト(図3では、外径側の交差ベルト142)の幅Wb2[mm]に対して1.00≦Wb1/Wb2≦1.40の範囲にあり、好ましくは1.10≦Wb1/Wb2≦1.35の範囲にある。また、最も幅狭な交差ベルトの幅Wb2[mm]が、タイヤ総幅SW[mm]に対して0.61≦Wb2/SW≦0.96の範囲にあり、好ましくは0.70≦Wb2/SW≦0.94の範囲にある。上記下限により、ベルトプライの幅が確保されて、タイヤ接地領域の接地圧分布が適正化されて、タイヤの耐偏摩耗性が確保される。上記上限により、タイヤ転動時におけるベルトプライの端部の歪が低減されて、ベルトプライ端部の周辺ゴムのセパレーションが抑制される。
Further, the width Wb1 [of the widest intersecting belt (in FIG. 3, the intersecting belt 141 on the inner diameter side) of the pair of intersecting belts 141 and 142 (the above-mentioned configuration includes the additional belt; not shown) mm] is in the range of 1.00≦Wb1/Wb2≦1.40 with respect to the width Wb2 [mm] of the narrowest cross belt (in FIG. 3, the cross belt 142 on the outer diameter side), and preferably It is in the range of 1.10≦Wb1/Wb2≦1.35. Further, the width Wb2 [mm] of the narrowest crossing belt is in the range of 0.61≦Wb2/SW≦0.96 with respect to the total tire width SW [mm], preferably 0.70≦Wb2/ SW is in the range of 0.94. With the above lower limit, the width of the belt ply is ensured, the ground contact pressure distribution in the tire ground contact area is optimized, and the uneven wear resistance of the tire is ensured. The above upper limit reduces distortion at the end of the belt ply during tire rolling, and suppresses separation of rubber around the end of the belt ply.
ベルトプライの幅は、各ベルトプライの左右の端部のタイヤ回転軸方向の距離であり、タイヤを規定リムに装着して規定内圧を付与すると共に無負荷状態として測定される。
The width of the belt ply is the distance between the left and right ends of each belt ply in the direction of the tire rotation axis, and is measured with the tire mounted on a specified rim, a specified internal pressure applied, and an unloaded state.
また、一対の交差ベルト141、142(上記した付加ベルトを備える構成では、付加ベルトを含む。図示省略)のうち最も幅広な交差ベルト(図3では、内径側の交差ベルト141)の幅Wb1[mm]が、タイヤ接地幅TW[mm]に対して0.85≦Wb1/TW≦1.23の範囲にあり、好ましくは0.90≦Wb1/TW≦1.20の範囲にある。
Further, the width Wb1 [of the widest intersecting belt (in FIG. 3, the intersecting belt 141 on the inner diameter side) of the pair of intersecting belts 141 and 142 (the above-mentioned configuration includes the additional belt; not shown) mm] is in the range of 0.85≦Wb1/TW≦1.23 with respect to the tire ground contact width TW [mm], preferably in the range of 0.90≦Wb1/TW≦1.20.
例えば、図1~図3の構成では、幅広な交差ベルト141がタイヤ径方向の最内層に配置され、幅狭な交差ベルト142が幅広な交差ベルト141の径方向外側に配置されている。また、ベルトカバー143が、幅狭な交差ベルト142の径方向外側に配置されて、一対の交差ベルト141、142の双方の全体を覆っている。また、一対のベルトエッジカバー144、144が、相互に離間しつつベルトカバー143の径方向外側に配置されて、一対の交差ベルト141、142の左右のエッジ部をそれぞれ覆っている。
For example, in the configurations shown in FIGS. 1 to 3, a wide cross belt 141 is arranged at the innermost layer in the radial direction of the tire, and a narrow cross belt 142 is arranged on the outer side in the radial direction of the wide cross belt 141. Further, the belt cover 143 is disposed on the radially outer side of the narrow cross belt 142 and covers both of the pair of cross belts 141 and 142 in their entirety. Further, a pair of belt edge covers 144, 144 are arranged radially outward of the belt cover 143 while being spaced apart from each other, and cover the left and right edge portions of the pair of intersecting belts 141, 142, respectively.
[トレッドプロファイルおよびトレッドゲージ]
図4は、図1に記載したタイヤ1のトレッド部を示す拡大図である。 [Tread profile and tread gauge]
FIG. 4 is an enlarged view showing the tread portion of thetire 1 shown in FIG.
図4は、図1に記載したタイヤ1のトレッド部を示す拡大図である。 [Tread profile and tread gauge]
FIG. 4 is an enlarged view showing the tread portion of the
図4において、タイヤ接地端Tにおけるトレッドプロファイルの落ち込み量DA[mm]、タイヤ接地幅TW[mm]およびタイヤ外径OD[mm]が、0.015≦TW/(DA×OD)≦0.300の関係を有し、好ましくは0.020≦TW/(DA×OD)≦0.250の関係を有する。また、タイヤ接地端Tにおけるトレッドプロファイルの落ち込み量DA[mm]が、タイヤ接地幅TW[mm]に対して0.01≦DA/TW≦0.10の関係を有し、好ましくは0.02≦DA/TW≦0.08の関係を有する。これにより、トレッド部ショルダー領域の落ち込み角(比DA/(TW/2)で定義される。)が適正化されて、トレッド部の負荷能力が適正に確保される。具体的に、上記下限により、トレッド部ショルダー領域の落ち込み角が確保されて、トレッド部ショルダー領域の接地圧が過大となることに起因する摩耗寿命の低下が抑制される。上記上限により、タイヤ接地領域がフラットになり接地圧が均一化されて、タイヤの耐摩耗性能が確保される。特に小径タイヤでは、高内圧および高負荷での使用が想定されるため、上記構成によりタイヤ接地領域の接地圧分布を効果的に最適化できる。
In FIG. 4, the depression amount DA [mm] of the tread profile at the tire ground contact edge T, the tire ground contact width TW [mm], and the tire outer diameter OD [mm] are 0.015≦TW/(DA×OD)≦0. 300, preferably 0.020≦TW/(DA×OD)≦0.250. Further, the depression amount DA [mm] of the tread profile at the tire ground contact edge T has a relationship of 0.01≦DA/TW≦0.10 with respect to the tire ground contact width TW [mm], preferably 0.02 The relationship is ≦DA/TW≦0.08. As a result, the depression angle (defined by the ratio DA/(TW/2)) of the shoulder region of the tread portion is optimized, and the load capacity of the tread portion is appropriately ensured. Specifically, with the above lower limit, the depression angle of the tread shoulder region is ensured, and a reduction in wear life due to excessive ground pressure in the tread shoulder region is suppressed. With the above upper limit, the tire ground contact area becomes flat, the ground contact pressure becomes uniform, and the wear resistance performance of the tire is ensured. In particular, small-diameter tires are expected to be used under high internal pressure and high load, so the above configuration can effectively optimize the ground pressure distribution in the tire ground contact area.
落ち込み量DAは、タイヤ子午線方向の断面視におけるタイヤ赤道面CLとトレッドプロファイルとの交点C1からタイヤ接地端Tまでのタイヤ径方向の距離であり、タイヤを規定リムに装着して規定内圧を付与すると共に無負荷状態として測定される。
The depression amount DA is the distance in the tire radial direction from the intersection C1 of the tire equatorial plane CL and the tread profile to the tire ground contact edge T in a cross-sectional view in the tire meridian direction, and the tire is mounted on a specified rim and a specified internal pressure is applied. It is also measured as a no-load condition.
タイヤのプロファイルは、タイヤ子午線方向の断面視におけるタイヤの輪郭線であり、レーザープロファイラを用いて計測される。レーザープロファイラとしては、例えば、タイヤプロファイル測定装置(株式会社マツオ製)が使用される。
The tire profile is the outline of the tire in a cross-sectional view in the tire meridian direction, and is measured using a laser profiler. As the laser profiler, for example, a tire profile measuring device (manufactured by Matsuo Co., Ltd.) is used.
また、タイヤ接地端Tにおけるトレッドプロファイルの落ち込み量DA[mm]が、タイヤ外径OD[mm]およびタイヤ総幅SW[mm]に対して以下の数式(5)を満たすことが好ましい。ここで、Emin=2.5、Emax=17であり、好ましくはEmin=3.8、Emax=13であり、さらに好ましくはEmin=4.0、Emax=9である。
Furthermore, it is preferable that the depression amount DA [mm] of the tread profile at the tire ground contact edge T satisfies the following formula (5) with respect to the tire outer diameter OD [mm] and the tire total width SW [mm]. Here, Emin=2.5 and Emax=17, preferably Emin=3.8 and Emax=13, and more preferably Emin=4.0 and Emax=9.
また、図4において、タイヤ赤道面CLにおけるトレッドプロファイル上の点C1と、タイヤ赤道面CLからタイヤ接地幅TWの1/4の距離におけるトレッドプロファイル上の一対の点C2、C2とを定義する。
Further, in FIG. 4, a point C1 on the tread profile at the tire equatorial plane CL and a pair of points C2, C2 on the tread profile at a distance of 1/4 of the tire ground contact width TW from the tire equatorial plane CL are defined.
このとき、点C1および一対の点C2を通る円弧の曲率半径TRc[mm]が、タイヤ外径OD[mm]に対して0.15≦TRc/OD≦15の範囲にあり、好ましくは0.18≦TRc/OD≦12の範囲にある。また、前記円弧の曲率半径TRc[mm]が30≦TRc≦3000の範囲にあり、好ましくは50≦TRc≦2800の範囲にあり、さらに好ましくは80≦TRc≦2500の範囲にある。これにより、トレッド部の負荷能力が適正に確保される。具体的に、上記下限により、トレッド部センター領域がフラットになりタイヤ接地領域の接地圧が均一化されて、タイヤの耐摩耗性能が確保される。上記上限により、トレッド部ショルダー領域の接地圧が過大となることに起因する摩耗寿命の低下が抑制される。特に小径タイヤでは、高内圧および高負荷での使用が想定されるため、かかる使用条件下における接地圧の均一化作用が効果的に得られる。
At this time, the radius of curvature TRc [mm] of the circular arc passing through the point C1 and the pair of points C2 is in the range of 0.15≦TRc/OD≦15 with respect to the tire outer diameter OD [mm], preferably 0.15≦TRc/OD≦15. It is in the range of 18≦TRc/OD≦12. Further, the radius of curvature TRc [mm] of the circular arc is in the range of 30≦TRc≦3000, preferably in the range of 50≦TRc≦2800, and more preferably in the range of 80≦TRc≦2500. Thereby, the load capacity of the tread portion is appropriately ensured. Specifically, with the above lower limit, the center region of the tread portion becomes flat, the ground contact pressure of the tire ground contact region is made uniform, and the wear resistance performance of the tire is ensured. The above upper limit suppresses a decrease in wear life caused by excessive ground contact pressure in the shoulder region of the tread. In particular, small-diameter tires are expected to be used under high internal pressure and high load, and therefore, the effect of equalizing ground pressure under such usage conditions can be effectively achieved.
円弧の曲率半径は、タイヤを規定リムに装着して規定内圧を付与すると共に無負荷状態として測定される。
The radius of curvature of the circular arc is measured with the tire mounted on a specified rim, a specified internal pressure applied, and an unloaded state.
また、図4において、上記したタイヤ赤道面CLの点C1および左右のタイヤ接地端T、Tを通る円弧の曲率半径TRw[mm]が、タイヤ外径OD[mm]に対して0.30≦TRw/OD≦16の範囲にあり、好ましくは0.35≦TRw/OD≦11の範囲にある。また、前記円弧の曲率半径TRw[mm]が、150≦TRw≦2800の範囲にあり、好ましくは200≦TRw≦2500の範囲にある。これにより、トレッド部の負荷能力が適正に確保される。具体的に、上記下限により、タイヤ接地領域の全体がフラットになり接地圧が均一化されて、タイヤの耐摩耗性能が確保される。上記上限により、トレッド部ショルダー領域の接地圧が過大となることに起因する摩耗寿命の低下が抑制される。特に小径タイヤでは、高内圧および高負荷での使用が想定されるため、上記構成によりタイヤ接地領域の接地圧分布を効果的に最適化できる。
In addition, in FIG. 4, the radius of curvature TRw [mm] of the arc passing through the point C1 on the tire equatorial plane CL and the left and right tire ground contact edges T, T is 0.30≦ relative to the tire outer diameter OD [mm]. TRw/OD≦16, preferably 0.35≦TRw/OD≦11. Further, the radius of curvature TRw [mm] of the circular arc is in the range of 150≦TRw≦2800, preferably in the range of 200≦TRw≦2500. Thereby, the load capacity of the tread portion is appropriately ensured. Specifically, with the above lower limit, the entire tire ground contact area becomes flat, the ground contact pressure is made uniform, and the wear resistance performance of the tire is ensured. The above upper limit suppresses a decrease in wear life caused by excessive ground contact pressure in the shoulder region of the tread. In particular, small-diameter tires are expected to be used under high internal pressure and high load, so the above configuration can effectively optimize the ground pressure distribution in the tire ground contact area.
また、上記した点C1、C2を通る第一円弧の曲率半径TRw[mm]が、点C1およびタイヤ接地端Tを通る第二円弧の曲率半径TRw[mm]に対して0.50≦TRw/TRc≦1.00の範囲にあり、好ましくは0.60≦TRw/TRc≦0.98の範囲にあり、より好ましくは0.70≦TRw/TRc≦0.96の範囲にある。これにより、タイヤの接地形状が適正化される。具体的に、上記下限により、トレッド部センター領域の接地圧が分散されて、タイヤの摩耗寿命が向上する。上記上限により、トレッド部ショルダー領域の接地圧が過大となることに起因する摩耗寿命の低下が抑制される。
Also, the radius of curvature TRw [mm] of the first arc passing through the points C1 and C2 described above is 0.50≦TRw/with respect to the radius of curvature TRw [mm] of the second arc passing through the point C1 and the tire contact edge T It is in the range of TRc≦1.00, preferably in the range of 0.60≦TRw/TRc≦0.98, and more preferably in the range of 0.70≦TRw/TRc≦0.96. Thereby, the ground contact shape of the tire is optimized. Specifically, the lower limit allows the ground pressure in the center region of the tread portion to be dispersed, thereby improving the wear life of the tire. The above upper limit suppresses a decrease in wear life caused by excessive ground contact pressure in the shoulder region of the tread.
また、図4において、タイヤ赤道面CLにおけるカーカス層13上の点B1と、左右のタイヤ接地端T、Tからカーカス層13に下した垂線の足B2、B2とを定義する。
In addition, in FIG. 4, a point B1 on the carcass layer 13 in the tire equatorial plane CL and legs B2, B2 of perpendicular lines drawn from the left and right tire contact edges T, T to the carcass layer 13 are defined.
このとき、点B1および一対の点B2、B2を通る円弧の曲率半径CRwが、上記した点C1およびタイヤ接地端T、Tを通る円弧の曲率半径TRwに対して0.35≦CRw/TRw≦1.60の範囲にあり、好ましくは0.45≦CRw/TRw≦1.50の範囲にあり、より好ましくは0.55≦CRw/TRw≦1.40の範囲にある。また、曲率半径CRw[mm]が、100≦CRw≦2500の範囲にあり、好ましくは120≦CRw≦2200の範囲にある。これにより、タイヤ接地形状がより適正化される。具体的に、上記下限により、トレッド部ショルダー領域のゴムゲージの増加に起因する摩耗寿命の低下が抑制される。上記上限により、トレッド部センター領域の摩耗寿命が確保される。
At this time, the radius of curvature CRw of the circular arc passing through point B1 and the pair of points B2, B2 is 0.35≦CRw/TRw≦ with respect to the radius of curvature TRw of the circular arc passing through point C1 and the tire contact edges T, T mentioned above. 1.60, preferably 0.45≦CRw/TRw≦1.50, more preferably 0.55≦CRw/TRw≦1.40. Further, the radius of curvature CRw [mm] is in the range of 100≦CRw≦2500, preferably in the range of 120≦CRw≦2200. This makes the tire ground contact shape more appropriate. Specifically, the above lower limit suppresses a decrease in wear life caused by an increase in the rubber gauge in the shoulder region of the tread. The above upper limit ensures the wear life of the center region of the tread portion.
図5は、図4に記載したトレッド部の片側領域を示す拡大図である。
FIG. 5 is an enlarged view showing one side area of the tread portion shown in FIG. 4.
図1の構成では、上記のように、ベルト層14が一対の交差ベルト141、142を有し、また、トレッドゴム15がキャップトレッド151およびアンダートレッド152を有する。
In the configuration of FIG. 1, as described above, the belt layer 14 has a pair of intersecting belts 141 and 142, and the tread rubber 15 has a cap tread 151 and an undertread 152.
また、図5において、タイヤ赤道面CLにおけるトレッドプロファイルから幅広な交差ベルト141の外周面までの距離Tce[mm]が、タイヤ外径OD[mm]に対して0.008≦Tce/OD≦0.13の関係を有し、好ましくは0.012≦Tce/OD≦0.10の関係を有し、より好ましくは0.015≦Tce/OD≦0.07の関係を有する。また、距離Tce[mm]が5≦Tce≦25の範囲にあり、好ましくは7≦Tce≦20の範囲にある。これにより、トレッド部の負荷能力が適正に確保される。具体的に、上記下限により、高負荷での使用時におけるタイヤ変形が抑制されて、タイヤの耐摩耗性能が確保される。特に小径タイヤでは、高内圧および高負荷での使用が想定されるため、上記した耐摩耗性能が顕著に得られる。上記上限により、トレッドゴムの質量増加に起因する転がり抵抗の悪化が抑制される。
In addition, in FIG. 5, the distance Tce [mm] from the tread profile in the tire equatorial plane CL to the outer peripheral surface of the wide cross belt 141 is 0.008≦Tce/OD≦0 with respect to the tire outer diameter OD [mm]. .13, preferably 0.012≦Tce/OD≦0.10, more preferably 0.015≦Tce/OD≦0.07. Further, the distance Tce [mm] is in the range of 5≦Tce≦25, preferably in the range of 7≦Tce≦20. Thereby, the load capacity of the tread portion is appropriately ensured. Specifically, the above lower limit suppresses tire deformation during use under high load, ensuring the wear resistance performance of the tire. In particular, small-diameter tires are expected to be used under high internal pressure and high load, so the above-mentioned wear resistance performance can be significantly achieved. The above upper limit suppresses deterioration of rolling resistance due to an increase in the mass of the tread rubber.
距離Tceは、タイヤを規定リムに装着して規定内圧を付与すると共に無負荷状態として測定される。
The distance Tce is measured when the tire is mounted on a specified rim, a specified internal pressure is applied, and there is no load.
ベルトプライの外周面は、ベルトコードおよびコートゴムから成るベルトプライの全体の径方向外側の周面として定義される。
The outer peripheral surface of the belt ply is defined as the entire radially outer peripheral surface of the belt ply consisting of the belt cord and coated rubber.
また、タイヤ赤道面CLにおけるトレッドプロファイルから幅広な交差ベルト141の外周面までの距離Tce[mm]が、タイヤ外径OD[mm]に対して以下の数式(6)を満たすことが好ましい。ここで、Fmin=35、Fmax=207であり、好ましくはFmin=42、Fmax=202である。
Further, it is preferable that the distance Tce [mm] from the tread profile in the tire equatorial plane CL to the outer peripheral surface of the wide cross belt 141 satisfies the following formula (6) with respect to the tire outer diameter OD [mm]. Here, Fmin=35 and Fmax=207, preferably Fmin=42 and Fmax=202.
また、タイヤ接地端Tにおけるトレッドプロファイルから幅広交差ベルト141の外周面までの距離Tsh[mm]が、タイヤ赤道面CLにおける距離Tce[mm]に対して0.60≦Tsh/Tce≦1.70の範囲にあり、好ましくは0.80≦Tsh/Tce≦1.60の範囲にあり、より好ましくは1.01≦Tsh/Tce≦1.50の範囲にある。上記下限により、ショルダー領域のトレッドゲージが確保されるので、タイヤ転動時におけるタイヤの繰り返し変形が抑制されて、タイヤの耐摩耗性能が確保される。また、上記上限により、センター領域のトレッドゲージが確保されるので、小径タイヤ特有の高負荷での使用時におけるタイヤ変形が抑制されて、タイヤの耐摩耗性能が確保される。
Further, the distance Tsh [mm] from the tread profile at the tire ground contact edge T to the outer peripheral surface of the wide cross belt 141 is 0.60≦Tsh/Tce≦1.70 with respect to the distance Tce [mm] at the tire equatorial plane CL. It is preferably in the range of 0.80≦Tsh/Tce≦1.60, more preferably in the range of 1.01≦Tsh/Tce≦1.50. The above lower limit ensures the tread gauge in the shoulder region, thereby suppressing repeated deformation of the tire during tire rolling, and ensuring the wear resistance performance of the tire. Moreover, since the above upper limit ensures a tread gauge in the center region, tire deformation during use under high loads peculiar to small-diameter tires is suppressed, and the wear resistance performance of the tire is ensured.
距離Tshは、タイヤを規定リムに装着して規定内圧を付与すると共に無負荷状態として測定される。また、タイヤ接地端Tの直下に幅広な交差ベルトが存在しない場合には、距離Tshがトレッドプロファイルからベルトプライの外周面を延長した仮想線までの距離として測定される。
The distance Tsh is measured when the tire is mounted on a specified rim, a specified internal pressure is applied, and there is no load. Further, when there is no wide crossing belt directly under the tire ground contact edge T, the distance Tsh is measured as the distance from the tread profile to an imaginary line that is an extension of the outer peripheral surface of the belt ply.
また、タイヤ接地端Tにおけるトレッドプロファイルから幅広交差ベルト141の外周面までの距離Tsh[mm]が、タイヤ赤道面CLにおける距離Tce[mm]に対して以下の数式(7)を満たすことが好ましい。ここで、Gmin=0.36、Gmax=0.72であり、好ましくはGmin=0.37、Gmax=0.71であり、より好ましくはGmin=0.38、Gmax=0.70である。
Further, it is preferable that the distance Tsh [mm] from the tread profile at the tire ground contact edge T to the outer peripheral surface of the wide cross belt 141 satisfies the following formula (7) with respect to the distance Tce [mm] at the tire equatorial plane CL. . Here, Gmin=0.36, Gmax=0.72, preferably Gmin=0.37, Gmax=0.71, more preferably Gmin=0.38, Gmax=0.70.
また、図5において、タイヤ接地幅TWの10[%]の幅ΔTWを有する区間を定義する。このとき、タイヤ接地領域の任意の区間におけるトレッドゴム15のゴムゲージの最大値Taと最小値Tbとの比が、0[%]以上40[%]以下の範囲にあり、好ましくは0[%]以上20[%]以下の範囲にある。かかる構成では、タイヤ接地領域の任意の区間(特にベルトプライ141~144の端部を含む区間)におけるトレッドゴム15のゴムゲージの変化量が小さく設定されるので、タイヤ幅方向における接地圧分布が滑らかとなり、タイヤの耐摩耗性能が向上する。
Further, in FIG. 5, a section having a width ΔTW of 10% of the tire ground contact width TW is defined. At this time, the ratio between the maximum value Ta and minimum value Tb of the rubber gauge of the tread rubber 15 in any section of the tire contact area is in the range of 0 [%] to 40 [%], preferably 0 [%]. It is in the range of 20 [%] or more. In this configuration, since the amount of change in the rubber gauge of the tread rubber 15 in any section of the tire ground contact area (particularly the section including the ends of the belt plies 141 to 144) is set small, the ground contact pressure distribution in the tire width direction is smooth. This improves the wear resistance of the tire.
トレッドゴム15のゴムゲージは、トレッドプロファイルからトレッドゴム15の内周面までの距離(図5では、キャップトレッド151の外周面からアンダートレッド152の内周面までの距離)として定義される。したがって、トレッド踏面に形成された溝が除外されて、トレッドゴム15のゴムゲージが測定される。
The rubber gauge of the tread rubber 15 is defined as the distance from the tread profile to the inner peripheral surface of the tread rubber 15 (in FIG. 5, the distance from the outer peripheral surface of the cap tread 151 to the inner peripheral surface of the undertread 152). Therefore, the rubber gauge of the tread rubber 15 is measured while excluding the grooves formed on the tread surface.
また、図5において、タイヤ赤道面CLにおけるアンダートレッド152のゴムゲージUTceが、上記したタイヤ赤道面CLにおける距離Tceに対して0.04≦UTce/Tce≦0.60の範囲にあり、好ましくは0.06≦UTce/Tce≦0.50の範囲にある。これにより、アンダートレッド152のゴムゲージUTceが適正化される。
Further, in FIG. 5, the rubber gauge UTce of the undertread 152 in the tire equatorial plane CL is in the range of 0.04≦UTce/Tce≦0.60, preferably 0. It is in the range of .06≦UTce/Tce≦0.50. Thereby, the rubber gauge UTce of the undertread 152 is optimized.
また、上記したタイヤ接地端Tにおける距離Tshが、幅広交差ベルト141の端部からカーカス層13の外周面までのゴムゲージTu[mm]に対して1.50≦Tsh/Tu≦6.90の範囲にあり、好ましくは2.00≦Tsh/Tu≦6.50の範囲にある。これにより、カーカス層13のプロファイルが適正化されてカーカス層13の張力が適正化される。具体的に、上記下限により、カーカス層の張力およびショルダー領域のトレッドゲージが確保されるので、タイヤ転動時におけるタイヤの繰り返し変形が抑制されて、タイヤの耐摩耗性能が確保される。上記上限により、ベルトプライの端部付近のゴムゲージが確保されるので、ベルトプライの周辺ゴムのセパレーションが抑制される。
Further, the distance Tsh at the tire ground contact edge T mentioned above is in the range of 1.50≦Tsh/Tu≦6.90 with respect to the rubber gauge Tu [mm] from the end of the wide cross belt 141 to the outer peripheral surface of the carcass layer 13. It is preferably in the range of 2.00≦Tsh/Tu≦6.50. Thereby, the profile of the carcass layer 13 is optimized and the tension of the carcass layer 13 is optimized. Specifically, the above lower limit ensures the tension of the carcass layer and the tread gauge of the shoulder region, thereby suppressing repeated deformation of the tire during tire rolling, and ensuring the wear resistance performance of the tire. Due to the above upper limit, a rubber gauge near the end of the belt ply is secured, so that separation of the rubber around the belt ply is suppressed.
ゴムゲージTuは、幅広交差ベルト141の端部とカーカス層13との間に挿入されたゴム部材(図5ではサイドウォールゴム16)のゲージとして測定される。具体的に、タイヤ子午線方向の断面視にて、幅広交差ベルト141の端部からカーカス層13の外面に下した垂線を作図し、この垂線上におけるゴム部材のトータルゲージがゴムゲージTuとして算出される。
The rubber gauge Tu is measured as a gauge of a rubber member (sidewall rubber 16 in FIG. 5) inserted between the end of the wide cross belt 141 and the carcass layer 13. Specifically, in a cross-sectional view in the tire meridian direction, a perpendicular line is drawn from the end of the wide cross belt 141 to the outer surface of the carcass layer 13, and the total gauge of the rubber member on this perpendicular line is calculated as the rubber gauge Tu. .
カーカス層13の外周面は、カーカスコードおよびコートゴムから成るカーカスプライの全体の径方向外側の周面として定義される。また、カーカス層13が複数のカーカスプライから成る多層構造を有する場合(図示省略)には、最外層のカーカスプライの外周面がカーカス層13の外周面を構成する。また、カーカス層13の巻き上げ部132(図1参照)が幅広交差ベルト141の端部とカーカス層13との間に存在する場合(図示省略)には、この巻き上げ部132の外周面がカーカス層13の外周面を構成する。
The outer peripheral surface of the carcass layer 13 is defined as the entire radially outer peripheral surface of the carcass ply made of the carcass cord and coated rubber. Further, when the carcass layer 13 has a multilayer structure consisting of a plurality of carcass plies (not shown), the outer circumferential surface of the outermost carcass ply constitutes the outer circumferential surface of the carcass layer 13. Further, when the rolled up part 132 (see FIG. 1) of the carcass layer 13 exists between the end of the wide cross belt 141 and the carcass layer 13 (not shown), the outer circumferential surface of this rolled up part 132 is This constitutes the outer peripheral surface of No. 13.
例えば、図5の構成では、サイドウォールゴム16が幅広交差ベルト141の端部とカーカス層13との間に挿入されて、幅広交差ベルト141の端部とカーカス層13との間のゴムゲージTuを形成している。しかし、これに限らず、例えばベルトクッションが、サイドウォールゴム16に代えて幅広交差ベルト141の端部とカーカス層13との間に挿入されても良い(図示省略)。また、挿入されたゴム部材が、46以上67以下のゴム硬さHs_sp、1.0以上3.5以下の100[%]伸長時のモジュラスM_sp[MPa]および0.02以上0.22以下の損失正接tanδ_spを有し、好ましくは48以上63以下のゴム硬さHs_sp、1.2以上3.2以下の100[%]伸長時のモジュラスM_sp[MPa]および0.04以上0.20以下の損失正接tanδ_spを有する。
For example, in the configuration of FIG. 5, the sidewall rubber 16 is inserted between the end of the wide cross belt 141 and the carcass layer 13, and the rubber gauge Tu between the end of the wide cross belt 141 and the carcass layer 13 is is forming. However, the invention is not limited to this, and for example, a belt cushion may be inserted between the end of the wide cross belt 141 and the carcass layer 13 instead of the sidewall rubber 16 (not shown). In addition, the inserted rubber member has a rubber hardness Hs_sp of 46 or more and 67 or less, a modulus M_sp at 100 [%] elongation of 1.0 or more and 3.5 or less [MPa], and a rubber hardness of 0.02 or more and 0.22 or less. It has a loss tangent tan δ_sp, preferably a rubber hardness Hs_sp of 48 or more and 63 or less, a modulus at 100 [%] elongation M_sp [MPa] of 1.2 or more and 3.2 or less, and a modulus M_sp [MPa] of 0.04 or more and 0.20 or less. It has a loss tangent tanδ_sp.
また、図1の構成では、タイヤ1が、タイヤ周方向に延在する複数の周方向主溝21~23(図5参照)と、これらの周方向主溝21~23に区画された陸部(図中の符号省略)とをトレッド面に備える。主溝は、JATMAに規定されるウェアインジケータの表示義務を有する溝として定義される。
Further, in the configuration of FIG. 1, the tire 1 has a plurality of circumferential main grooves 21 to 23 (see FIG. 5) extending in the tire circumferential direction, and a land portion divided by these circumferential main grooves 21 to 23. (numerals omitted in the figure) are provided on the tread surface. The main groove is defined as a groove that is required to display a wear indicator as defined in JATMA.
このとき、図5に示すように、複数の周方向主溝21~23のうちタイヤ赤道面CLに最も近い周方向主溝21の溝深さGd1[mm]が、トレッドゴム15のゴムゲージGce[mm]に対して0.50≦Gd1/Gce≦1.00の範囲にあり、好ましくは0.55≦Gd1/Gce≦0.98の範囲にある。これにより、タイヤの耐摩耗性能が確保される。具体的に、上記下限により、トレッド部センター領域の接地圧が分散されて、タイヤの摩耗寿命が向上する。上記上限により、陸部の剛性が確保され、また、周方向主溝21の溝底からベルト層までのゴムゲージが確保される。
At this time, as shown in FIG. 5, the groove depth Gd1 [mm] of the circumferential main groove 21 closest to the tire equatorial plane CL among the plurality of circumferential main grooves 21 to 23 is determined by the rubber gauge Gce[mm] of the tread rubber 15. mm] is in the range of 0.50≦Gd1/Gce≦1.00, preferably in the range of 0.55≦Gd1/Gce≦0.98. This ensures the wear resistance of the tire. Specifically, the lower limit allows the ground pressure in the center region of the tread portion to be dispersed, thereby improving the wear life of the tire. The above upper limit ensures the rigidity of the land portion and also ensures the rubber gauge from the bottom of the circumferential main groove 21 to the belt layer.
タイヤ赤道面CLに最も近い周方向主溝は、タイヤ赤道面CL上にある周方向主溝21(図5参照)として定義され、タイヤ赤道面CL上に周方向主溝がない場合(図示省略)には、タイヤ赤道面CLから最も近い周方向主溝として定義される。
The circumferential main groove closest to the tire equatorial plane CL is defined as the circumferential main groove 21 (see FIG. 5) located on the tire equatorial plane CL, and when there is no circumferential main groove on the tire equatorial plane CL (not shown) ) is defined as the circumferential main groove closest to the tire equatorial plane CL.
また、上記した比Gd1/Gceが、タイヤ外径OD[mm]に対して以下の数式(8)を満たすことが好ましい。ここで、Hmin=0.10、Hmax=0.60であり、好ましくはHmin=0.12、Hmax=0.50であり、より好ましくはHmin=0.14、Hmax=0.40である。
Further, it is preferable that the ratio Gd1/Gce described above satisfies the following formula (8) with respect to the tire outer diameter OD [mm]. Here, Hmin=0.10, Hmax=0.60, preferably Hmin=0.12, Hmax=0.50, more preferably Hmin=0.14, Hmax=0.40.
また、複数の周方向主溝21~23のうちタイヤ赤道面CLに最も近い周方向主溝21の溝深さGd1[mm]が、他の周方向主溝22、23の溝深さGd2[mm]、Gd3[mm]以上である(Gd2≦Gd1、Gd3≦Gd1)。具体的には、タイヤ赤道面CLからタイヤ接地端Tまでの領域をタイヤ幅方向に二等分したときに、タイヤ赤道面CLに最も近い周方向主溝(図中の符号省略)の溝深さGd1が、タイヤ接地端T側の領域にある他の周方向主溝(図中の符号省略)の溝深さGd2、Gd3の最大値に対して1.00倍以上2.50倍以下の範囲にあり、好ましくは1.01倍以上2.00倍以下の範囲にあり、より好ましくは1.05倍以上1.80倍以下の範囲にある。上記下限により、トレッド部センター領域の接地圧が分散されて、タイヤの耐摩耗性能が向上する。上記上限により、トレッド部センター領域とショルダー領域との接地圧差が過大となることに起因する偏摩耗が抑制される。
Further, among the plurality of circumferential main grooves 21 to 23, the groove depth Gd1 [mm] of the circumferential main groove 21 closest to the tire equatorial plane CL is different from the groove depth Gd2 [mm] of the other circumferential main grooves 22 and 23. mm], Gd3 [mm] or more (Gd2≦Gd1, Gd3≦Gd1). Specifically, when the area from the tire equatorial plane CL to the tire ground contact edge T is divided into two equal parts in the tire width direction, the groove depth of the circumferential main groove (number omitted in the figure) closest to the tire equatorial plane CL. The groove depth Gd1 is 1.00 times or more and 2.50 times or less the maximum value of the groove depths Gd2 and Gd3 of other circumferential main grooves (numerals omitted in the figure) in the area on the tire contact edge T side. It is preferably in the range of 1.01 times or more and 2.00 times or less, more preferably in the range of 1.05 times or more and 1.80 times or less. With the above lower limit, the ground contact pressure in the center region of the tread portion is dispersed, and the wear resistance performance of the tire is improved. The above upper limit suppresses uneven wear caused by an excessive ground contact pressure difference between the tread center region and the shoulder region.
[サイドプロファイルおよびサイドゲージ]
図6は、図1に記載したタイヤ1のサイドフォール部およびビード部を示す拡大図である。図7は、図6に記載したサイドウォール部を示す拡大図である。 [Side profile and side gauge]
FIG. 6 is an enlarged view showing a side fall portion and a bead portion of thetire 1 shown in FIG. FIG. 7 is an enlarged view showing the sidewall portion shown in FIG. 6.
図6は、図1に記載したタイヤ1のサイドフォール部およびビード部を示す拡大図である。図7は、図6に記載したサイドウォール部を示す拡大図である。 [Side profile and side gauge]
FIG. 6 is an enlarged view showing a side fall portion and a bead portion of the
図6において、ベルト層14の最内層(図6では、内径側交差ベルト141)の端部に対してタイヤ径方向の同位置にあるサイドプロファイル上の点Auと、ビードコア11の径方向外側の端部に対してタイヤ径方向の同位置にあるサイドプロファイル上の点Alとを定義する。また、タイヤ最大幅位置Acから点Auまでのタイヤ径方向の距離Huと、タイヤ最大幅位置Acから点Alまでのタイヤ径方向の距離Hlとを定義する。また、タイヤ最大幅位置Acから距離Huの70[%]の径方向位置にあるサイドプロファイル上の点Au’と、タイヤ最大幅位置Acから距離Hlの70[%]の径方向位置にあるサイドプロファイル上の点Al’と、を定義する。
In FIG. 6, a point Au on the side profile at the same position in the tire radial direction with respect to the end of the innermost layer of the belt layer 14 (inner radial cross belt 141 in FIG. 6) and a point Au on the radially outer side of the bead core 11 A point Al on the side profile at the same position in the tire radial direction with respect to the end is defined. Further, a distance Hu in the tire radial direction from the tire maximum width position Ac to a point Au, and a distance Hl in the tire radial direction from the tire maximum width position Ac to a point Al are defined. In addition, a point Au' on the side profile is located at a radial position of 70% of the distance Hu from the tire maximum width position Ac, and a side is located at a radial position of 70% of the distance Hl from the tire maximum width position Ac. A point Al' on the profile is defined.
このとき、距離Hu[mm]および距離Hl[mm]の和が、タイヤ断面高さSH[mm](図2参照)に対して0.45≦(Hu+Hl)/SH≦0.90の範囲にあり、好ましくは0.50≦(Hu+Hl)/SH≦0.85の範囲にある。これにより、ベルト層14からビードコア11までの径方向距離が適正化される。具体的に、上記下限により、タイヤサイド部の変形可能な領域が確保されて、タイヤサイド部の故障(例えばビードフィラー12の径方向外側端部におけるゴム部材のセパレーション)が抑制される。上記上限により、タイヤ転動時におけるタイヤサイド部の撓み量が低減されて、タイヤの転がり抵抗が低減される。
At this time, the sum of the distance Hu [mm] and the distance Hl [mm] is in the range of 0.45≦(Hu+Hl)/SH≦0.90 with respect to the tire cross-sectional height SH [mm] (see Fig. 2). 0.50≦(Hu+Hl)/SH≦0.85. Thereby, the radial distance from the belt layer 14 to the bead core 11 is optimized. Specifically, the above lower limit ensures a deformable region of the tire side portion, thereby suppressing failure of the tire side portion (for example, separation of the rubber member at the radially outer end of the bead filler 12). With the above upper limit, the amount of deflection of the tire side portion when the tire is rolling is reduced, and the rolling resistance of the tire is reduced.
距離Huおよび距離Hlは、タイヤを規定リムに装着して規定内圧を付与すると共に無負荷状態として測定される。
The distance Hu and the distance Hl are measured with the tire mounted on a specified rim, a specified internal pressure applied, and an unloaded state.
また、距離Hu[mm]および距離Hl[mm]の和が、タイヤ外径OD(図1)、タイヤ断面高さSH[mm](図2参照)およびタイヤ最大幅位置Ac、点Au’および点Al’を通る円弧の曲率半径RSc[mm]に対して以下の数式(9)を満たすことが好ましい。ここで、I1min=0.06、I1max=0.20、I2=0.70であり、好ましくはI1min=0.09、I1max=0.20、I2=0.65である。
In addition, the sum of the distance Hu [mm] and the distance Hl [mm] is the tire outer diameter OD (Figure 1), the tire cross-sectional height SH [mm] (see Figure 2), the tire maximum width position Ac, the points Au' and It is preferable that the following formula (9) be satisfied for the radius of curvature RSc [mm] of the arc passing through the point Al'. Here, I1min=0.06, I1max=0.20, and I2=0.70, preferably I1min=0.09, I1max=0.20, and I2=0.65.
円弧の曲率半径RScは、タイヤを規定リムに装着して規定内圧を付与すると共に無負荷状態として測定される。
The radius of curvature RSc of the circular arc is measured with the tire mounted on a specified rim, a specified internal pressure applied, and an unloaded state.
また、距離Hu[mm]および距離Hl[mm]が、0.30≦Hu/(Hu+Hl)≦0.70の関係を有し、好ましくは0.35≦Hu/(Hu+Hl)≦0.65の関係を有する。これにより、タイヤサイド部の変形可能な領域におけるタイヤ最大幅位置Acの位置が適正化される。具体的に、上記下限により、タイヤ最大幅位置Acがベルト層14の端部に近過ぎることに起因するベルトプライの端部付近の応力集中が緩和されて、周辺ゴムのセパレーションが抑制される。上記上限により、タイヤ最大幅位置Acがビードコア11の端部に近過ぎることに起因するビード部付近の応力集中が緩和されて、ビード部の補強部材(図6ではビードフィラー12)の故障が抑制される。
Further, the distance Hu [mm] and the distance Hl [mm] have a relationship of 0.30≦Hu/(Hu+Hl)≦0.70, preferably 0.35≦Hu/(Hu+Hl)≦0.65. have a relationship Thereby, the position of the tire maximum width position Ac in the deformable region of the tire side portion is optimized. Specifically, the lower limit alleviates stress concentration near the end of the belt ply caused by the tire maximum width position Ac being too close to the end of the belt layer 14, thereby suppressing separation of the surrounding rubber. Due to the above upper limit, stress concentration near the bead caused by the tire maximum width position Ac being too close to the end of the bead core 11 is alleviated, and failure of the bead reinforcing member (bead filler 12 in FIG. 6) is suppressed. be done.
また、タイヤ最大幅位置Ac、点Au’および点Al’を通る円弧の曲率半径RSc[mm]が、タイヤ外径OD[mm]に対して0.05≦RSc/OD≦1.70の範囲にあり、好ましくは0.10≦RSc/OD≦1.60の範囲にある。また、前記円弧の曲率半径RSc[mm]が、25≦RSc≦330の範囲にあり、好ましくは30≦RSc≦300の範囲にある。これにより、サイドプロファイルの曲率半径が適正化されて、タイヤサイド部の負荷能力が適正に確保される。具体的に、上記下限により、タイヤ転動時におけるタイヤサイド部の撓み量が低減されて、タイヤの転がり抵抗が低減される。上記上限により、タイヤサイド部がフラットになることに起因する応力集中が緩和されて、タイヤの耐久性能が向上する。特に小径タイヤでは、上記した高内圧および高負荷での使用によりタイヤサイド部に大きな応力が作用する傾向にあるため、タイヤの耐サイドカット性能を確保すべき課題もある。この点において、上記下限により、サイドプロファイルの曲率半径が確保され、カーカス張力が適正化されることでタイヤのつぶれが抑制されて、タイヤのサイドカットが抑制される。また、上記上限により、カーカス層13の張力が過大となることに起因するタイヤのサイドカットが抑制される。
Further, the radius of curvature RSc [mm] of the arc passing through the tire maximum width position Ac, point Au' and point Al' is in the range of 0.05≦RSc/OD≦1.70 with respect to the tire outer diameter OD [mm]. and preferably in the range of 0.10≦RSc/OD≦1.60. Further, the radius of curvature RSc [mm] of the circular arc is in the range of 25≦RSc≦330, preferably in the range of 30≦RSc≦300. As a result, the radius of curvature of the side profile is optimized, and the load capacity of the tire side portion is appropriately ensured. Specifically, the above lower limit reduces the amount of deflection of the tire side portion when the tire rolls, thereby reducing the rolling resistance of the tire. With the above upper limit, stress concentration caused by flattening of the tire side portion is alleviated, and the durability of the tire is improved. Particularly in small-diameter tires, large stress tends to act on the tire side portions due to use under the above-mentioned high internal pressure and high load, so there is also the issue of ensuring the side cut resistance of the tire. In this respect, the lower limit ensures the radius of curvature of the side profile and optimizes the carcass tension, thereby suppressing tire collapse and suppressing tire side cuts. Furthermore, the above upper limit suppresses side cuts in the tire due to excessive tension in the carcass layer 13.
また、円弧の曲率半径RSc[mm]が、タイヤ断面高さSH[mm]に対して0.50≦RSc/SH≦0.99の範囲にあり、好ましくは0.55≦RSc/SH≦0.97の範囲にある。
Further, the radius of curvature RSc [mm] of the circular arc is in the range of 0.50≦RSc/SH≦0.99 with respect to the tire cross-sectional height SH [mm], preferably 0.55≦RSc/SH≦0. It is in the range of .97.
また、円弧の曲率半径RSc[mm]が、タイヤ外径OD[mm]およびリム径RD[mm]に対して以下の数式(10)を満たすことが好ましい。ここで、Jmin=15、Jmax=360であり、好ましくはJmin=20、Jmax=330であり、より好ましくはJmin=25、Jmax=300である。
Furthermore, it is preferable that the radius of curvature RSc [mm] of the circular arc satisfies the following formula (10) with respect to the tire outer diameter OD [mm] and the rim diameter RD [mm]. Here, Jmin=15, Jmax=360, preferably Jmin=20, Jmax=330, more preferably Jmin=25, Jmax=300.
また、図6において、タイヤ最大幅位置Acに対してタイヤ径方向の同位置にあるカーカス層13の本体部131上の点Bcを定義する。また、タイヤ最大幅位置Acから上記した距離Huの70[%]の径方向位置にあるカーカス層13の本体部131上の点Bu’を定義する。また、タイヤ最大幅位置Acから上記した距離Hlの70[%]の径方向位置にあるカーカス層13の本体部131上の点Bl’を定義する。
Further, in FIG. 6, a point Bc on the main body portion 131 of the carcass layer 13 is defined at the same position in the tire radial direction as the tire maximum width position Ac. Further, a point Bu' on the main body portion 131 of the carcass layer 13 is defined at a radial position of 70% of the distance Hu described above from the tire maximum width position Ac. Further, a point Bl' on the main body portion 131 of the carcass layer 13 is defined at a radial position of 70% of the distance Hl described above from the tire maximum width position Ac.
このとき、上記したタイヤ最大幅位置Ac、点Au’および点Al’を通る円弧の曲率半径RSc[mm]が、点Bc、点Bu’および点Bl’を通る円弧の曲率半径RCc[mm]に対して1.10≦RSc/RCc≦4.00の範囲にあり、好ましくは1.50≦RSc/RCc≦3.50の範囲にある。また、点Bc、点Bu’および点Bl’を通る円弧の曲率半径RCc[mm]が、5≦RCc≦300の範囲にあり、好ましくは10≦RCc≦270の範囲にある。これにより、タイヤのサイドプロファイルの曲率半径RScとカーカス層13のサイドプロファイルの曲率半径RCcとの関係が適正化される。具体的に、上記下限により、カーカスプロファイルの曲率半径RCcが確保され、後述するタイヤの内容積Vが確保されて、タイヤの負荷能力が確保される。上記上限により、後述するタイヤサイド部のトータルゲージGuおよびGlが確保されて、タイヤサイド部の負荷能力が確保される。
At this time, the radius of curvature RSc [mm] of the arc passing through the tire maximum width position Ac, point Au' and point Al' is the radius of curvature RCc [mm] of the arc passing through point Bc, point Bu' and point Bl'. 1.10≦RSc/RCc≦4.00, preferably 1.50≦RSc/RCc≦3.50. Further, the radius of curvature RCc [mm] of the arc passing through point Bc, point Bu', and point Bl' is in the range of 5≦RCc≦300, preferably in the range of 10≦RCc≦270. Thereby, the relationship between the radius of curvature RSc of the side profile of the tire and the radius of curvature RCc of the side profile of the carcass layer 13 is optimized. Specifically, the above lower limit ensures the radius of curvature RCc of the carcass profile, the internal volume V of the tire described below, and the load capacity of the tire. With the above upper limit, the total gauges Gu and Gl of the tire side portion, which will be described later, are ensured, and the load capacity of the tire side portion is ensured.
また、上記したサイドプロファイルの曲率半径RSc[mm]が、上記カーカスプロファイルの曲率半径RCc[mm]およびタイヤ外径OD[mm]に対して以下の数式(11)を満たすことが好ましい。ここで、Kmin=1、Kmax=130であり、好ましくはKmin=2、Kmax=100であり、より好ましくはKmin=3、Kmax=70である。
Furthermore, it is preferable that the radius of curvature RSc [mm] of the side profile described above satisfies the following formula (11) with respect to the radius of curvature RCc [mm] of the carcass profile and the tire outer diameter OD [mm]. Here, Kmin=1 and Kmax=130, preferably Kmin=2 and Kmax=100, more preferably Kmin=3 and Kmax=70.
また、図6において、上記した点Auにおけるタイヤサイド部のトータルゲージGu[mm]が、タイヤ外径OD[mm]に対して0.010≦Gu/OD≦0.080の範囲にあり、好ましくは0.015≦Gu/OD≦0.050の範囲にある。これにより、タイヤサイド部の径方向外側領域のトータルゲージGuが適正化される。具体的に、上記下限により、タイヤサイド部の径方向外側領域のトータルゲージGuが確保され、高負荷での使用時におけるタイヤ変形が抑制されて、タイヤの耐久性能が確保される。特に小径タイヤでは、高内圧および高負荷での使用を想定されるため、上記したタイヤの転がり抵抗の低減作用が顕著に得られる。上記上限により、トータルゲージGuが過大となることに起因するタイヤの転がり抵抗の悪化が抑制される。
In addition, in FIG. 6, the total gauge Gu [mm] of the tire side portion at the point Au described above is preferably in the range of 0.010≦Gu/OD≦0.080 with respect to the tire outer diameter OD [mm]. is in the range of 0.015≦Gu/OD≦0.050. Thereby, the total gauge Gu of the radially outer region of the tire side portion is optimized. Specifically, the above lower limit ensures the total gauge Gu of the radially outer region of the tire side portion, suppresses tire deformation during use under high load, and ensures tire durability. In particular, small-diameter tires are expected to be used under high internal pressure and high load, so the above-described effect of reducing the rolling resistance of the tire can be significantly achieved. The above upper limit suppresses deterioration of the rolling resistance of the tire due to the total gauge Gu becoming excessively large.
タイヤサイド部のトータルゲージは、サイドプロファイル上の所定の点からカーカス層13の本体部131に引いた垂線上におけるサイドプロファイルからタイヤ内面までの距離として測定される。
The total gauge of the tire side part is measured as the distance from the side profile to the inner surface of the tire on a perpendicular line drawn from a predetermined point on the side profile to the main body part 131 of the carcass layer 13.
また、図6において、上記した点AuにおけるトータルゲージGu[mm]が、タイヤ最大幅位置Acにおけるタイヤサイド部のトータルゲージGc[mm]に対して1.30≦Gu/Gc≦5.00の範囲にあり、好ましくは1.50≦Gu/Gc≦4.00の範囲にある。これにより、タイヤ最大幅位置Acからベルト層14の最内層に至るタイヤサイド部のゲージ配分が適正化される。具体的に、上記下限により、径方向外側領域のトータルゲージGuが確保され、高負荷での使用時におけるタイヤ変形が抑制されて、タイヤの耐久性能が確保される。上記上限により、トータルゲージGuが過大となることに起因するタイヤの転がり抵抗の悪化が抑制される。
In addition, in FIG. 6, the total gauge Gu [mm] at the point Au mentioned above is 1.30≦Gu/Gc≦5.00 with respect to the total gauge Gc [mm] of the tire side part at the tire maximum width position Ac. within the range, preferably within the range of 1.50≦Gu/Gc≦4.00. Thereby, the gauge distribution in the tire side portion from the tire maximum width position Ac to the innermost layer of the belt layer 14 is optimized. Specifically, the lower limit ensures the total gauge Gu in the radially outer region, suppresses tire deformation during use under high load, and ensures tire durability. The above upper limit suppresses deterioration of the rolling resistance of the tire due to the total gauge Gu becoming excessively large.
また、上記した点AuにおけるトータルゲージGu[mm]が、タイヤ最大幅位置AcにおけるトータルゲージGc[mm]およびタイヤ外径OD[mm]に対して以下の数式(12)を満たすことが好ましい。ここで、Lmin=0.10、Lmax=0.70であり、好ましくはLmin=0.14、Lmax=0.70であり、より好ましくはLmin=0.19、Lmax=0.70である。
Further, it is preferable that the total gauge Gu [mm] at the above point Au satisfies the following formula (12) with respect to the total gauge Gc [mm] at the tire maximum width position Ac and the tire outer diameter OD [mm]. Here, Lmin=0.10, Lmax=0.70, preferably Lmin=0.14, Lmax=0.70, more preferably Lmin=0.19, Lmax=0.70.
また、図6において、タイヤ最大幅位置Acにおけるタイヤサイド部のトータルゲージGc[mm]が、タイヤ外径OD[mm]に対して0.003≦Gc/OD≦0.060の関係を有し、好ましくは0.004≦Gc/OD≦0.050の関係を有する。上記下限により、タイヤ最大幅位置AcのトータルゲージGcが確保されて、タイヤの負荷能力が確保される。上記上限により、タイヤ最大幅位置AcのトータルゲージGcを薄くしたことによるタイヤの転がり抵抗の低減作用が確保される。
In addition, in FIG. 6, the total gauge Gc [mm] of the tire side portion at the tire maximum width position Ac has a relationship of 0.003≦Gc/OD≦0.060 with respect to the tire outer diameter OD [mm]. , preferably has a relationship of 0.004≦Gc/OD≦0.050. With the above lower limit, the total gauge Gc at the tire maximum width position Ac is ensured, and the load capacity of the tire is ensured. The above upper limit ensures that the rolling resistance of the tire is reduced by thinning the total gauge Gc at the tire maximum width position Ac.
また、タイヤ最大幅位置AcにおけるトータルゲージGc[mm]が、タイヤ外径OD[mm]に対して以下の数式(13)を満たすことが好ましい。ここで、Mmin=70、Mmax=450であり、好ましくはMmin=80、Mmax=400である。
Furthermore, it is preferable that the total gauge Gc [mm] at the tire maximum width position Ac satisfies the following formula (13) with respect to the tire outer diameter OD [mm]. Here, Mmin=70 and Mmax=450, preferably Mmin=80 and Mmax=400.
また、タイヤ最大幅位置AcにおけるトータルゲージGc[mm]が、タイヤ外径OD[mm]およびタイヤ総幅SW[mm]に対して以下の数式(14)を満たすことが好ましい。ここで、Nmin=0.20、Nmax=15であり、好ましくはNmin=0.40、Nmax=15であり、より好ましくはNmin=0.60、Nmax=12である。
Further, it is preferable that the total gauge Gc [mm] at the tire maximum width position Ac satisfies the following formula (14) with respect to the tire outer diameter OD [mm] and the tire total width SW [mm]. Here, Nmin=0.20, Nmax=15, preferably Nmin=0.40, Nmax=15, more preferably Nmin=0.60, Nmax=12.
また、タイヤ最大幅位置AcにおけるトータルゲージGc[mm]が、上記したタイヤ最大幅位置Ac、点Au’および点Al’を通る円弧の曲率半径RSc[mm]に対して以下の数式(15)を満たすことが好ましい。ここで、Omin=13、Omax=260であり、好ましくはOmin=20、Omax=200である。
Furthermore, the total gauge Gc [mm] at the tire maximum width position Ac is expressed by the following formula (15) for the radius of curvature RSc [mm] of the arc passing through the tire maximum width position Ac, points Au' and points Al'. It is preferable to satisfy the following. Here, Omin=13 and Omax=260, preferably Omin=20 and Omax=200.
また、図6において、上記した点Alにおけるタイヤサイド部のトータルゲージGl[mm]が、タイヤ外径ODに対して0.010≦Gl/OD≦0.150の範囲にあり、好ましくは0.015≦Gl/OD≦0.100の範囲にある。これにより、タイヤサイド部の径方向内側領域のトータルゲージGlが適正化される。具体的に、上記下限により、タイヤサイド部の径方向内側領域のトータルゲージGlが確保され、高負荷での使用時におけるタイヤ変形が抑制されて、タイヤの耐久性能が確保される。特に小径タイヤでは、高内圧および高負荷での使用を想定されるため、上記したタイヤの転がり抵抗の低減作用が顕著に得られる。上記上限により、トータルゲージGlが過大となることに起因するタイヤの転がり抵抗の悪化が抑制される。
Further, in FIG. 6, the total gauge Gl [mm] of the tire side portion at the above-mentioned point Al is in the range of 0.010≦Gl/OD≦0.150 with respect to the tire outer diameter OD, preferably 0.010≦Gl/OD≦0.150. 015≦Gl/OD≦0.100. As a result, the total gauge Gl in the radially inner region of the tire side portion is optimized. Specifically, the above lower limit ensures the total gauge Gl of the radially inner region of the tire side portion, suppresses tire deformation during use under high load, and ensures tire durability. In particular, small-diameter tires are expected to be used under high internal pressure and high load, so the above-described effect of reducing the rolling resistance of the tire can be significantly achieved. The above upper limit suppresses deterioration of the rolling resistance of the tire due to the total gauge Gl becoming excessively large.
また、図6において、上記した点Alにおけるタイヤサイド部のトータルゲージGl[mm]とタイヤ最大幅位置Acにおけるタイヤサイド部のトータルゲージGc[mm]との比Gl/Gcが、1.00≦Gl/Gc≦7.00の範囲にあり、好ましくは1.50≦Gl/Gc≦4.00の範囲にある。これにより、タイヤ最大幅位置Acからビードコア11に至るタイヤサイド部のゲージ配分が適正化される。具体的に、上記下限により、径方向内側領域のトータルゲージGlが確保され、高負荷での使用時におけるタイヤ変形が抑制されて、タイヤの耐久性能が確保される。上記上限により、トータルゲージGlが過大となることに起因するタイヤの転がり抵抗の悪化が抑制される。
In addition, in FIG. 6, the ratio Gl/Gc between the total gauge Gl [mm] of the tire side part at the above-mentioned point Al and the total gauge Gc [mm] of the tire side part at the tire maximum width position Ac is 1.00≦ Gl/Gc≦7.00, preferably 1.50≦Gl/Gc≦4.00. Thereby, the gauge distribution in the tire side portion from the tire maximum width position Ac to the bead core 11 is optimized. Specifically, the above lower limit ensures the total gauge Gl in the radially inner region, suppresses tire deformation during use under high load, and ensures tire durability. The above upper limit suppresses deterioration of the rolling resistance of the tire due to the total gauge Gl becoming excessively large.
また、上記した点Alにおけるタイヤサイド部のトータルゲージGl[mm]が、タイヤ最大幅位置AcにおけるトータルゲージGc[mm]およびタイヤ外径OD[mm]に対して以下の数式(16)を満たすことが好ましい。ここで、Pmin=0.12、Pmax=1.00であり、好ましくはPmin=0.15、Pmax=1.00であり、より好ましくはPmin=0.18、Pmax=1.00である。
Further, the total gauge Gl [mm] of the tire side portion at the above-mentioned point Al satisfies the following formula (16) with respect to the total gauge Gc [mm] at the tire maximum width position Ac and the tire outer diameter OD [mm]. It is preferable. Here, Pmin=0.12, Pmax=1.00, preferably Pmin=0.15, Pmax=1.00, more preferably Pmin=0.18, Pmax=1.00.
また、図6において、上記した点AlにおけるトータルゲージGl[mm]が、上記した点AuにおけるトータルゲージGu[mm]に対して0.50≦Gl/Gu≦5.00の範囲にあり、好ましくは1.00≦Gl/Gu≦3.00の範囲にある。これにより、タイヤサイド部の径方向外側領域のトータルゲージGlと径方向内側領域のトータルゲージGuとの比が適正化される。
Further, in FIG. 6, the total gauge Gl [mm] at the above-mentioned point Al is preferably in the range of 0.50≦Gl/Gu≦5.00 with respect to the total gauge Gu [mm] at the above-mentioned point Au. is in the range of 1.00≦Gl/Gu≦3.00. As a result, the ratio between the total gauge Gl in the radially outer region of the tire side portion and the total gauge Gu in the radially inner region is optimized.
また、上記した点AlにおけるトータルゲージGl[mm]が、上記した点AuにおけるトータルゲージGu[mm]およびタイヤ外径OD[mm]に対して以下の数式(17)を満たすことが好ましい。ここで、Qmin=0.09、Qmax=0.80であり、好ましくはQmin=0.10、Qmax=0.70であり、より好ましくはQmin=0.11、Qmax=0.50である。
Furthermore, it is preferable that the total gauge Gl [mm] at the above-mentioned point Al satisfies the following formula (17) with respect to the total gauge Gu [mm] at the above-mentioned point Au and the tire outer diameter OD [mm]. Here, Qmin=0.09, Qmax=0.80, preferably Qmin=0.10, Qmax=0.70, more preferably Qmin=0.11, Qmax=0.50.
また、図6において、トータルゲージGcの測定位置における平均ゴム硬さHscと、トータルゲージGuの測定位置における平均ゴム硬さHsuと、トータルゲージGlの測定点位置における平均ゴム硬さHslとが、Hsc≦Hsu<Hslの関係を有し、好ましくは1≦Hsu-Hsc≦18および2≦Hsl-Hsu≦27の関係を有し、より好ましくは2≦Hsu-Hsc≦15および5≦Hsl-Hsu≦23の関係を有する。これにより、タイヤサイド部のゴム硬さの関係が適正化される。
In addition, in FIG. 6, the average rubber hardness Hsc at the measurement position of the total gauge Gc, the average rubber hardness Hsu at the measurement position of the total gauge Gu, and the average rubber hardness Hsl at the measurement point position of the total gauge Gl are as follows. Hsc≦Hsu<Hsl, preferably 1≦Hsu-Hsc≦18 and 2≦Hsl-Hsu≦27, more preferably 2≦Hsu-Hsc≦15 and 5≦Hsl-Hsu The relationship is ≦23. As a result, the relationship between the rubber hardness of the tire side portions is optimized.
平均ゴム硬さHsc、Hsu、Hslは、タイヤ最大幅位置AcのトータルゲージGc[mm]、点AuのトータルゲージGuおよび点AlのトータルゲージGlのそれぞれの測定点における、各ゴム部材の断面長さとゴム硬さとの積をトータルゲージで除した数値の総和として算出される。
The average rubber hardness Hsc, Hsu, Hsl is the cross-sectional length of each rubber member at each measurement point of the total gauge Gc [mm] at the tire maximum width position Ac, the total gauge Gu at point Au, and the total gauge Gl at point Al. It is calculated as the sum of the product of rubber hardness and rubber hardness divided by the total gauge.
また、図7において、タイヤ最大幅位置Acから点Au’までのタイヤ幅方向の距離ΔAu’[mm]が、上記したタイヤ最大幅位置Acからの距離Hu[mm]の70%に対して0.03≦ΔAu’/(Hu×0.70)≦0.25の範囲にあり、好ましくは0.07≦ΔAu’/(Hu×0.70)≦0.23の範囲にある。これにより、径方向外側領域におけるサイドプロファイルの湾曲度が適正化される。具体的に、上記下限により、タイヤサイド部がフラットになることに起因する応力集中が緩和されて、タイヤの耐久性能が向上する。上記上限により、タイヤ転動時におけるタイヤサイド部の撓み量が低減されて、タイヤの転がり抵抗が低減される。特に小径タイヤでは、上記した高内圧および高負荷での使用によりタイヤサイド部に大きな応力が作用する傾向にあるため、タイヤの耐サイドカット性能を確保すべき課題もある。この点において、上記下限により、サイドプロファイルの曲率半径が確保され、カーカス張力が適正化されることでタイヤのつぶれが抑制されて、タイヤのサイドカットが抑制される。また、上記上限により、カーカス層13の張力が過大となることに起因するタイヤのサイドカットが抑制される。
In addition, in FIG. 7, the distance ΔAu' [mm] in the tire width direction from the tire maximum width position Ac to the point Au' is 0 for 70% of the distance Hu [mm] from the tire maximum width position Ac. It is in the range of .03≦ΔAu'/(Hu×0.70)≦0.25, preferably in the range of 0.07≦ΔAu′/(Hu×0.70)≦0.23. Thereby, the degree of curvature of the side profile in the radially outer region is optimized. Specifically, the above lower limit alleviates stress concentration caused by flattening of the tire side portion, and improves the durability performance of the tire. With the above upper limit, the amount of deflection of the tire side portion when the tire is rolling is reduced, and the rolling resistance of the tire is reduced. Particularly in small-diameter tires, large stress tends to act on the tire side portions due to use under the above-mentioned high internal pressure and high load, so there is also the issue of ensuring the side cut resistance of the tire. In this respect, the lower limit ensures the radius of curvature of the side profile and optimizes the carcass tension, thereby suppressing tire collapse and suppressing tire side cuts. Furthermore, the above upper limit suppresses side cuts in the tire due to excessive tension in the carcass layer 13.
また、タイヤ最大幅位置Acから点Al’までのタイヤ幅方向の距離ΔAl’[mm]が、タイヤ最大幅位置Acからの距離Hl[mm]の70%に対して0.03≦ΔAl’/(Hl×0.70)≦0.28の範囲にあり、好ましくは0.07≦ΔAl’/(Hl×0.70)≦0.20の範囲にある。これにより、径方向内側領域におけるサイドプロファイルの湾曲度が適正化される。具体的に、上記下限により、タイヤサイド部がフラットになることに起因する応力集中が緩和されて、タイヤの耐久性能が向上する。特に小径タイヤでは、上記のようにビードコア11が補強されるため、ビードコア11付近における応力集中が効果的に抑制される。上記上限により、タイヤ転動時におけるタイヤサイド部の撓み量が低減されて、タイヤの転がり抵抗が低減される。
Further, the distance ΔAl' [mm] in the tire width direction from the tire maximum width position Ac to the point Al' is 0.03≦ΔAl'/ for 70% of the distance Hl [mm] from the tire maximum width position Ac. It is in the range of (Hl×0.70)≦0.28, preferably in the range of 0.07≦ΔAl′/(Hl×0.70)≦0.20. Thereby, the degree of curvature of the side profile in the radially inner region is optimized. Specifically, the above lower limit alleviates stress concentration caused by flattening of the tire side portion, and improves the durability performance of the tire. Particularly in small-diameter tires, since the bead core 11 is reinforced as described above, stress concentration near the bead core 11 is effectively suppressed. With the above upper limit, the amount of deflection of the tire side portion when the tire is rolling is reduced, and the rolling resistance of the tire is reduced.
距離ΔAu’、ΔAl’は、タイヤを規定リムに装着して規定内圧を付与すると共に無負荷状態として測定される。
The distances ΔAu' and ΔAl' are measured when the tire is mounted on a specified rim, a specified internal pressure is applied, and there is no load.
また、タイヤ最大幅位置Acから点Au’までのタイヤ幅方向の距離ΔAu’[mm]が、上記したタイヤ最大幅位置Ac、点Au’および点Al’を通る円弧の曲率半径RSc[mm]に対して以下の数式(18)を満たすことが好ましい。ここで、Rmin=0.05、Rmax=5.00であり、好ましくはRmin=0.10、Rmax=4.50である。
Further, the distance ΔAu' [mm] in the tire width direction from the tire maximum width position Ac to the point Au' is the radius of curvature RSc [mm] of the arc passing through the tire maximum width position Ac, the point Au', and the point Al'. It is preferable that the following formula (18) be satisfied for . Here, Rmin=0.05 and Rmax=5.00, preferably Rmin=0.10 and Rmax=4.50.
また、図7において、点Bcから点Bu’までのタイヤ幅方向の距離ΔBu’[mm]が、タイヤ最大幅位置から点Au’までのタイヤ幅方向の距離ΔAu’[mm]に対して1.00≦ΔBu’/ΔAu’≦7.00の範囲にあり、好ましくは1.10≦ΔBu’/ΔAu’≦6.00の範囲にある。これにより、径方向外側領域におけるサイドプロファイルの湾曲度とカーカスプロファイルの湾曲度との関係が適正化される。具体的に、上記下限により、タイヤサイド部の耐カット性能が確保される。上記上限により、カーカス層13の張力が確保され、タイヤサイド部の剛性が確保されて、タイヤの負荷能力および耐久性能が確保される。
In addition, in FIG. 7, the distance ΔBu' [mm] in the tire width direction from point Bc to point Bu' is 1 for the distance ΔAu' [mm] in the tire width direction from the tire maximum width position to point Au'. It is in the range of .00≦ΔBu'/ΔAu'≦7.00, preferably in the range of 1.10≦ΔBu'/ΔAu'≦6.00. This optimizes the relationship between the degree of curvature of the side profile and the degree of curvature of the carcass profile in the radially outer region. Specifically, the cut resistance of the tire side portion is ensured by the above lower limit. The above upper limit ensures the tension of the carcass layer 13, the rigidity of the tire side parts, and the load capacity and durability of the tire.
また、図7において、点Bcから点Bl’までのタイヤ幅方向の距離ΔBl’[mm]が、タイヤ最大幅位置Acから点Al’までのタイヤ幅方向の距離ΔAl’[mm]に対して2.00≦ΔBl’/ΔAl’≦11.0の範囲にあり、好ましくは1.90≦ΔBl’/ΔAl’≦9.50の範囲にある。これにより、径方向内側領域におけるサイドプロファイルの湾曲度とカーカスプロファイルの湾曲度との関係が適正化される。具体的に、上記下限により、タイヤサイド部のトータルゲージGlが確保されて、タイヤサイド部の負荷能力が確保される。上記上限により、カーカス層13の張力が確保され、タイヤサイド部の剛性が確保されて、タイヤの負荷能力および耐久性能が確保される。
In addition, in FIG. 7, the distance ΔBl' [mm] in the tire width direction from point Bc to point Bl' is relative to the distance ΔAl' [mm] in the tire width direction from the tire maximum width position Ac to point Al'. It is in the range of 2.00≦ΔBl'/ΔAl'≦11.0, preferably in the range of 1.90≦ΔBl'/ΔAl'≦9.50. This optimizes the relationship between the degree of curvature of the side profile and the degree of curvature of the carcass profile in the radially inner region. Specifically, the total gauge Gl of the tire side portion is ensured by the above lower limit, and the load capacity of the tire side portion is ensured. The above upper limit ensures the tension of the carcass layer 13, the rigidity of the tire side parts, and the load capacity and durability of the tire.
距離ΔBu’、ΔBl’は、タイヤを規定リムに装着して規定内圧を付与すると共に無負荷状態として測定される。
The distances ΔBu' and ΔBl' are measured when the tire is mounted on a specified rim, a specified internal pressure is applied, and there is no load.
また、点Bcから点Bu’までのタイヤ幅方向の距離ΔBu’[mm]が、上記した点Bc、点Bu’および点Bl’を通る円弧の曲率半径RCc[mm]に対して以下の数式(19)を満たすことが好ましい。ここで、Smin=0.40、Smax=7.0であり、好ましくはSmin=0.50、Smax=6.0である。
Further, the distance ΔBu' [mm] in the tire width direction from point Bc to point Bu' is calculated using the following formula for the radius of curvature RCc [mm] of the arc passing through the points Bc, Bu', and Bl' mentioned above. It is preferable that (19) is satisfied. Here, Smin=0.40 and Smax=7.0, preferably Smin=0.50 and Smax=6.0.
また、図7において、タイヤ最大幅位置Acにおけるサイドウォールゴム16のゴムゲージGcr[mm]が、上記したタイヤ最大幅位置AcのトータルゲージGc[mm]に対して0.35≦Gcr/Gc≦0.90の範囲にある。また、サイドウォールゴム16のゴムゲージGcr[mm]が1.5≦Gcrの範囲にあり、好ましくは2.0≦Gcrの範囲にある。上記下限により、サイドウォールゴム16のゴムゲージGcr[mm]が確保されて、サイドウォール部の負荷能力が確保される。
In addition, in FIG. 7, the rubber gauge Gcr [mm] of the sidewall rubber 16 at the tire maximum width position Ac is 0.35≦Gcr/Gc≦0 with respect to the above-mentioned total gauge Gc [mm] at the tire maximum width position Ac. It is in the range of .90. Further, the rubber gauge Gcr [mm] of the sidewall rubber 16 is in the range of 1.5≦Gcr, preferably in the range of 2.0≦Gcr. With the above lower limit, the rubber gauge Gcr [mm] of the sidewall rubber 16 is ensured, and the load capacity of the sidewall portion is ensured.
また、タイヤ最大幅位置Acにおけるサイドウォールゴム16のゴムゲージGcr[mm]が、上記したタイヤ最大幅位置AcのトータルゲージGc[mm]およびタイヤ外径OD[mm]に対して以下の数式(20)を満たすことが好ましい。ここで、Tmin=80、Tmax=0.90であり、好ましくはTmin=120、Tmax=0.90である。
Further, the rubber gauge Gcr [mm] of the sidewall rubber 16 at the tire maximum width position Ac is determined by the following formula (20 ) is preferably satisfied. Here, Tmin=80 and Tmax=0.90, preferably Tmin=120 and Tmax=0.90.
また、図7において、タイヤ最大幅位置Acにおけるインナーライナ18のゴムゲージGin[mm](図示省略)が、タイヤ最大幅位置AcのトータルゲージGc[mm]に対して0.03≦Gin/Gc≦0.50の範囲にあり、好ましくは0.05≦Gin/Gc≦0.40の範囲にある。これにより、カーカス層13の内面が適正に保護される。
In addition, in FIG. 7, the rubber gauge Gin [mm] (not shown) of the inner liner 18 at the tire maximum width position Ac is 0.03≦Gin/Gc≦ with respect to the total gauge Gc [mm] at the tire maximum width position Ac. It is in the range of 0.50, preferably in the range of 0.05≦Gin/Gc≦0.40. Thereby, the inner surface of the carcass layer 13 is properly protected.
[カーカスプライおよびベルトプライ]
図8は、図1に記載したタイヤのカーカス層およびベルト層の積層構造を示す説明図である。同図は、タイヤ子午線方向の断面視における拡大図を示している。 [Carcass ply and belt ply]
FIG. 8 is an explanatory diagram showing a laminated structure of a carcass layer and a belt layer of the tire shown in FIG. 1. This figure shows an enlarged cross-sectional view in the tire meridian direction.
図8は、図1に記載したタイヤのカーカス層およびベルト層の積層構造を示す説明図である。同図は、タイヤ子午線方向の断面視における拡大図を示している。 [Carcass ply and belt ply]
FIG. 8 is an explanatory diagram showing a laminated structure of a carcass layer and a belt layer of the tire shown in FIG. 1. This figure shows an enlarged cross-sectional view in the tire meridian direction.
図1の構成では、図8に示すように、カーカス層13が、カーカスコード13ccをコートゴム13crで被覆して成る単層のカーカスプライ13Aから成り、また、ベルト層14が、ベルトコード14bcをコートゴム14crで被覆して成る一対の交差ベルト141、142を積層して成る。また、インナーライナ18が、カーカス層13の内周面を覆って配置される。しかし、上記に限らず、カーカス層13が、2層のカーカスプライを積層して構成されても良い(後述する図9参照)。
In the configuration of FIG. 1, as shown in FIG. 8, the carcass layer 13 consists of a single-layer carcass ply 13A formed by covering a carcass cord 13cc with a coated rubber 13cr, and the belt layer 14 consists of a belt cord 14bc coated with rubber. It is constructed by laminating a pair of crossed belts 141 and 142 coated with 14cr. Further, an inner liner 18 is arranged to cover the inner peripheral surface of the carcass layer 13. However, the present invention is not limited to the above, and the carcass layer 13 may be constructed by laminating two carcass plies (see FIG. 9 described later).
また、図8において、図4の点B2、B2の間の領域におけるカーカスプライ13A(カーカス層13が2層のカーカスプライを積層して成る構成(図示省略)では、最内層のカーカスプライ)のカーカスコード13ccの外径の中心からタイヤ内面までの距離TL[mm]が、タイヤ外径OD[mm](図1参照)に対して0.00005≦TL/OD≦0.01000の範囲にあり、好ましくは0.00008≦TL/OD≦0.00900の範囲にある。また、距離TL[mm]が、タイヤ総幅SW[mm](図1参照)に対して0.00050≦TL/SW≦0.02500の範囲にあり、好ましくは0.00060≦TL/SW≦0.02300の範囲にある。上記下限により、エア漏れが適正に抑制され、上記上限により、タイヤ重量の増加が抑制される。また、距離TL[mm]の最小値TL_minが0.10≦TL_minであることが好ましい。また、図4の点B2、B2の間の領域における距離TL[mm]の最小値TL_minおよび最大値TL_maxが、0.30≦TL_min/TL_max≦1.00の関係を有し、好ましくは、0.40≦TL_min/TL_max≦1.00の関係を有する。これにより、カーカスコード13ccからタイヤ内面までの距離TLが上記領域にて均一に設定される。
In addition, in FIG. 8, the carcass ply 13A (the innermost carcass ply in a structure in which the carcass layer 13 is formed by laminating two carcass plies (not shown)) in the area between points B2 and B2 in FIG. The distance TL [mm] from the center of the outer diameter of the carcass cord 13cc to the inner surface of the tire is in the range of 0.00005≦TL/OD≦0.01000 with respect to the tire outer diameter OD [mm] (see Fig. 1). , preferably in the range of 0.00008≦TL/OD≦0.00900. Further, the distance TL [mm] is in the range of 0.00050≦TL/SW≦0.02500 with respect to the total tire width SW [mm] (see Fig. 1), preferably 0.00060≦TL/SW≦ It is in the range of 0.02300. The above lower limit appropriately suppresses air leakage, and the above upper limit suppresses an increase in tire weight. Moreover, it is preferable that the minimum value TL_min of the distance TL [mm] is 0.10≦TL_min. Further, the minimum value TL_min and maximum value TL_max of the distance TL [mm] in the area between points B2 and B2 in FIG. 4 have a relationship of 0.30≦TL_min/TL_max≦1.00, preferably 0. The relationship is .40≦TL_min/TL_max≦1.00. Thereby, the distance TL from the carcass cord 13cc to the inner surface of the tire is set uniformly in the above region.
距離TL[mm]は、上記した2点B2、B2(図4参照)の間の領域における任意の測定点で定義される。
The distance TL [mm] is defined at any measurement point in the area between the two points B2 and B2 (see FIG. 4) described above.
また、距離TL[mm]が、タイヤ総幅SW[mm]、タイヤ外径OD[mm]およびリム径RD[mm](図1参照)に対して1/350000≦TL/(SW×(OD-RD))≦1/3760の範囲にある。
Also, the distance TL [mm] is 1/350000≦TL/(SW×(OD -RD))≦1/3760.
また、図8において、図4の点B2、B2の間の領域の任意の点におけるカーカスプライ13A(カーカス層13が2層のカーカスプライを積層して成る構成(図示省略)では、最内層のカーカスプライ)のカーカスコード13ccの中心から最内層のカーカスプライ13Aの外面までの距離TCSU[mm]が、最内層のカーカスプライ13Aのカーカスコード13ccの中心からタイヤ内面までの距離TL[mm]に対して0.09≦TCSU/TL≦4.50の範囲にあり、好ましくは0.10≦TCSU/TL≦4.00の範囲にある。上記下限により、エア漏れが適正に抑制され、上記上限により、タイヤ重量の増加が抑制される。
In addition, in FIG. 8, the carcass ply 13A at any point in the area between points B2 and B2 in FIG. The distance TCSU [mm] from the center of the carcass cord 13cc of the carcass ply to the outer surface of the innermost carcass ply 13A is equal to the distance TL [mm] from the center of the carcass cord 13cc of the innermost carcass ply 13A to the inner surface of the tire. On the other hand, it is in the range of 0.09≦TCSU/TL≦4.50, preferably in the range of 0.10≦TCSU/TL≦4.00. The above lower limit appropriately suppresses air leakage, and the above upper limit suppresses an increase in tire weight.
また、図8において、カーカスプライ13Aのコートゴム13crの100[%]伸張時のモジュラスMC[MPa]が、インナーライナ18の100[%]伸張時のモジュラスMIL[MPa]およびベルト層14の最内層のベルトプライ141のコートゴム14crの100[%]伸張時のモジュラスMB[MPa]に対してMIL≦MC≦MBの範囲にある。また、比MC/MILが、1.00≦MC/MIL≦5.00の範囲にあり、好ましくは1.10≦MC/MIL≦4.50の範囲にある。また、比MB/MCが、1.00≦MB/MC≦2.40の範囲にあり、好ましくは1.00≦MB/MC≦2.20の範囲にある。また、カーカスプライ13Aのコートゴム13crのモジュラスMC[MPa]が、1.5≦MC≦12.0の範囲にあり、好ましくは2.0≦MC≦10.0の範囲にある。これにより、エア漏れが適正に抑制され、また、タイヤの耐久性能が確保される。
In addition, in FIG. 8, the modulus MC [MPa] of the coat rubber 13cr of the carcass ply 13A at 100 [%] elongation is the same as the modulus MIL [MPa] of the inner liner 18 at 100 [%] elongation and the innermost layer of the belt layer 14. The modulus MB [MPa] of the coating rubber 14cr of the belt ply 141 at 100 [%] elongation is in the range of MIL≦MC≦MB. Further, the ratio MC/MIL is in the range of 1.00≦MC/MIL≦5.00, preferably in the range of 1.10≦MC/MIL≦4.50. Further, the ratio MB/MC is in the range of 1.00≦MB/MC≦2.40, preferably in the range of 1.00≦MB/MC≦2.20. Further, the modulus MC [MPa] of the coat rubber 13cr of the carcass ply 13A is in the range of 1.5≦MC≦12.0, preferably in the range of 2.0≦MC≦10.0. As a result, air leakage is appropriately suppressed and the durability of the tire is ensured.
また、図8において、カーカスプライ13Aの厚さTC[mm]と、カーカスプライ13Aのコートゴム13crの60[℃]における損失正接tanδとの積が、0.05≦TC×tanδ≦0.55の範囲にあり、好ましくは0.07≦TC×tanδ≦0.50の範囲にある。これにより、カーカス層13の発熱が適正に抑制され、また、タイヤの耐久性能が確保される。
In addition, in FIG. 8, the product of the thickness TC [mm] of the carcass ply 13A and the loss tangent tan δ of the coating rubber 13cr of the carcass ply 13A at 60 [°C] satisfies 0.05≦TC×tanδ≦0.55. preferably within the range of 0.07≦TC×tanδ≦0.50. Thereby, heat generation in the carcass layer 13 is appropriately suppressed, and the durability of the tire is ensured.
図9は、図8に記載したカーカス層13およびベルト層14の積層構造の変形例を示す説明図である。
FIG. 9 is an explanatory diagram showing a modification of the laminated structure of the carcass layer 13 and belt layer 14 shown in FIG. 8.
図8の構成では、上記のようにカーカス層13が単層のカーカスプライ13Aから構成される。例えば、カーカスプライ13Aのカーカスコード13ccが、無機繊維、特にスチールコードから成る場合が想定される。
In the configuration of FIG. 8, the carcass layer 13 is composed of the single layer carcass ply 13A as described above. For example, it is assumed that the carcass cord 13cc of the carcass ply 13A is made of inorganic fiber, particularly steel cord.
しかし、これに限らず、図9に示すように、カーカス層13が2層のカーカスプライ13A、13Bを積層して成る構造を有しても良い。例えば、カーカスプライ13A、13Bのカーカスコード13ccが有機繊維材から成る場合が想定される。また、かかる構成では、カーカス層13の最外層のカーカスプライ13Bとベルト層14の最内層のベルトプライ(図9では内径側交差ベルト141)との幅25[mm]あたりの剥離力Hpp[N/25mm]が、カーカスプライ13Bのカーカスコード13ccの外径の中心からベルトプライ141のベルトコード14bcの外径の中心までの距離TCB[mm]に対して90≦Hpp/TCB≦300の範囲にあり、100≦Hpp/TCB≦250の範囲にあることが好ましい。また、剥離力Hpp[N/25mm]が、カーカスプライのカーカスコード13ccの打ち込み本数Ecs[本/50mm]に対して1.50≦Hpp/Ecs≦15.0の範囲にあり、好ましくは1.80≦Hpp/Ecs≦10.0の範囲にある。これにより、タイヤの耐久性が確保される。
However, the present invention is not limited to this, and as shown in FIG. 9, the carcass layer 13 may have a structure in which two carcass plies 13A and 13B are laminated. For example, it is assumed that the carcass cords 13cc of the carcass plies 13A and 13B are made of organic fiber material. In addition, in this configuration, a peeling force Hpp [N /25mm] is in the range of 90≦Hpp/TCB≦300 with respect to the distance TCB [mm] from the center of the outer diameter of the carcass cord 13cc of the carcass ply 13B to the center of the outer diameter of the belt cord 14bc of the belt ply 141. It is preferable that the range is 100≦Hpp/TCB≦250. Further, the peeling force Hpp [N/25mm] is in the range of 1.50≦Hpp/Ecs≦15.0, preferably 1.50≦Hpp/Ecs≦15.0 with respect to the number of installed carcass cords Ecs [pieces/50mm] of 13cc of carcass cords of the carcass ply. It is in the range of 80≦Hpp/Ecs≦10.0. This ensures the durability of the tire.
剥離力Hpp[N/25mm]は、カーカスコードの延在方向に長尺な矩形状を有すると共に25[mm]の幅および100[mm]以上の長さ(好ましくは、約50[mm]の試験つかみ代を含む150[mm]以上の長さ)を有する試験サンプルが用いられ、解析された波状曲線のピーク値の最大値および最小値の平均値として算出される。また、試験サンプルの数が2以上であることが好ましい。
The peeling force Hpp [N/25mm] has a long rectangular shape in the extending direction of the carcass cord, a width of 25 [mm], and a length of 100 [mm] or more (preferably about 50 [mm]). A test sample having a length of 150 [mm] or more (including the test gripping margin) is used, and it is calculated as the average value of the maximum and minimum peak values of the analyzed wavy curve. Further, it is preferable that the number of test samples is two or more.
図10は、図8に記載したカーカス層13およびベルト層14の積層構造の変形例を示す説明図である。
FIG. 10 is an explanatory diagram showing a modification of the laminated structure of the carcass layer 13 and belt layer 14 shown in FIG. 8.
図1の構成では、上記のように、ベルト層14が、一対の交差ベルト141、142と、ベルトカバー143および一対のベルトエッジカバー144、144とから構成される。また、図8に示すように、一対の交差ベルト141、142がカーカス層13の外周面に隣接して積層される。
In the configuration of FIG. 1, as described above, the belt layer 14 is composed of a pair of intersecting belts 141, 142, a belt cover 143, and a pair of belt edge covers 144, 144. Further, as shown in FIG. 8, a pair of cross belts 141 and 142 are laminated adjacent to the outer peripheral surface of the carcass layer 13.
これに対して、図10の構成では、ベルト層14が、第三の交差ベルトである追加ベルト145を有する。追加ベルト145は、一対の交差ベルト141、142の外周に積層される。
In contrast, in the configuration of FIG. 10, the belt layer 14 includes an additional belt 145, which is a third intersecting belt. The additional belt 145 is laminated around the outer periphery of the pair of intersecting belts 141 and 142.
また、図10において、一対の交差ベルト141、142および追加ベルト145のうち隣り合うベルトプライのコード間距離Hb(図10では、一対の交差ベルト141、142のコード間距離Hb1、ならびに、外径側交差ベルト142および追加ベルト145のコード間距離Hb2)を定義する。このとき、少なくとも一組のベルトプライの端部におけるコード間距離Hb_sh(図示省略)が、タイヤ赤道面CLにおけるコード間距離Hb_ce(図示省略)に対して1.05≦Hb_sh/Hb_ce≦2.00の範囲にあり、好ましくは1.50≦Hb_sh/Hb_ce≦1.80の範囲にある。したがって、コード間距離Hbが、トレッド部センター領域で大きく設定されることが好ましい。上記下限により、ベルト層14によるタイヤ外径成長の抑制作用が効果的に得られ、上記上限により、ベルト層の耐久性が確保される。上記の構成は、例えば、ベルトプライのコートゴムのゲージをトレッド部センター領域で厚くした構成、隣り合うベルトプライ間に追加ゴムシートを挿入した構成などにより実現される(図示省略)。
In FIG. 10, the distance Hb between the cords of adjacent belt plies among the pair of crossed belts 141, 142 and the additional belt 145 (in FIG. 10, the distance Hb1 between the cords of the pair of crossed belts 141, 142, and the outer diameter The inter-cord distance Hb2) of the side crossing belt 142 and the additional belt 145 is defined. At this time, the distance between cords Hb_sh (not shown) at the ends of at least one set of belt plies is 1.05≦Hb_sh/Hb_ce≦2.00 with respect to the distance between cords Hb_ce (not shown) in the tire equatorial plane CL. It is preferably in the range of 1.50≦Hb_sh/Hb_ce≦1.80. Therefore, it is preferable that the inter-cord distance Hb is set large in the tread center region. The above lower limit allows the belt layer 14 to effectively suppress the tire outer diameter growth, and the above upper limit ensures the durability of the belt layer. The above configuration is realized, for example, by making the gauge of the coated rubber of the belt ply thicker in the center region of the tread portion, or by inserting an additional rubber sheet between adjacent belt plies (not shown).
[タイヤ径方向外側領域]
図11は、図6に記載したタイヤ径方向外側領域を示す拡大図である。 [Tire radial outer area]
FIG. 11 is an enlarged view showing the tire radially outer region shown in FIG. 6. FIG.
図11は、図6に記載したタイヤ径方向外側領域を示す拡大図である。 [Tire radial outer area]
FIG. 11 is an enlarged view showing the tire radially outer region shown in FIG. 6. FIG.
図11において、タイヤ最大幅位置Acから上記した距離Huの35[%]の径方向位置にあるサイドプロファイル上の点Anを定義する。点Anは、タイヤ径方向におけるタイヤ最大幅位置Acと上記したサイドプロファイル上の点Au’との中点に相当する。
In FIG. 11, a point An on the side profile located at a radial position of 35% of the distance Hu described above from the tire maximum width position Ac is defined. Point An corresponds to the midpoint between the tire maximum width position Ac in the tire radial direction and the above-mentioned point Au' on the side profile.
このとき、タイヤを規定リムに装着して規定内圧を付与すると共に無負荷状態としたときのタイヤ最大幅位置Ac、点Au’および点Amを通る円弧の曲率半径RP[mm]が、タイヤ断面高さSH[mm](図2参照)に対して0.20≦RP/SH≦1.80の範囲にあり、好ましくは0.70≦RP/SH≦1.60の範囲にある。また、上記無負荷状態における円弧の曲率半径RP[mm]が、30≦RP≦250の範囲にあり、好ましくは50≦RP≦200の範囲にある。
At this time, the radius of curvature RP [mm] of the circular arc passing through the tire maximum width position Ac, point Au', and point Am when the tire is mounted on the specified rim, the specified internal pressure is applied, and the tire is in an unloaded state is the cross section of the tire. The height SH [mm] (see FIG. 2) is in the range of 0.20≦RP/SH≦1.80, preferably in the range of 0.70≦RP/SH≦1.60. Further, the radius of curvature RP [mm] of the arc in the above-mentioned no-load state is in the range of 30≦RP≦250, preferably in the range of 50≦RP≦200.
例えば、図11の構成では、サイドプロファイルが、タイヤ最大幅位置Acからベルト層14の最内層141の端部付近の点Auまでの領域(上記した距離Huの領域)にて単一の変曲点(図示省略)をもつ緩やかなS字形状を有し、この変曲点からタイヤ最大幅位置Ac側の領域でタイヤ外側に凸となり、バットレス部側の領域でタイヤ内側に凸となる形状を有している。また、S字形状の変曲点が、距離Huの70[%]の径方向位置にある点Au’の近傍にある。このため、サイドプロファイルが、タイヤ最大幅位置Acから点Au’までの領域でタイヤ外側に凸となる、略円弧形状を有する。このため、上記した曲率半径RP[mm]を定義する円弧が、タイヤ外側に凸となる形状を有する。
For example, in the configuration of FIG. 11, the side profile has a single inflection in the area from the tire maximum width position Ac to the point Au near the end of the innermost layer 141 of the belt layer 14 (the area of the above-mentioned distance Hu). It has a gentle S-shape with a point (not shown), and from this inflection point, the area on the tire maximum width position Ac side is convex to the outside of the tire, and the area on the buttress side is convex to the inside of the tire. have. Further, the S-shaped inflection point is near the point Au' located at a radial position of 70% of the distance Hu. Therefore, the side profile has a substantially circular arc shape that is convex toward the outside of the tire in the area from the tire maximum width position Ac to the point Au'. Therefore, the arc defining the radius of curvature RP [mm] has a shape that is convex toward the outside of the tire.
上記の構成では、タイヤサイド部からバットレス部に至るタイヤ径方向外側領域におけるサイドプロファイルの曲率半径RPが適正化されて、タイヤの接地性能と耐久性能とが両立し、タイヤの負荷能力が適正に確保される。具体的に、比RP/SHの上記下限により、タイヤ転動時におけるタイヤ径方向外側領域の撓み量が低減されて、トレッド部ショルダー領域の接地長が過長となることが抑制される。これにより、タイヤの接地形状が適正化されて、タイヤの接地性能(特に騒音性能)が確保される。また、比RP/SHの上記上限により、タイヤ径方向外側領域がフラットになることに起因する応力集中が緩和されて、タイヤの耐久性能が向上する。特に小径タイヤでは、上記した高負荷で使用されるため、トレッド部ショルダー領域の接地長が長くなり、また、タイヤサイド部に大きな応力が作用する傾向にある。したがって、上記構成が小径タイヤに採用されることで、タイヤの接地性能および耐久性能の向上作用顕著に得られる。
In the above configuration, the radius of curvature RP of the side profile in the tire radial outer region from the tire side part to the buttress part is optimized, the tire's ground contact performance and durability are compatible, and the tire's load capacity is properly adjusted. Secured. Specifically, the above-mentioned lower limit of the ratio RP/SH reduces the amount of deflection of the tire radially outer region when the tire rolls, and prevents the ground contact length of the tread shoulder region from becoming excessively long. Thereby, the ground contact shape of the tire is optimized, and the ground contact performance (especially noise performance) of the tire is ensured. Furthermore, the above upper limit of the ratio RP/SH alleviates stress concentration caused by flattening of the tire's radially outer region, thereby improving tire durability. Particularly in small-diameter tires, since they are used under the above-mentioned high loads, the contact length of the shoulder region of the tread portion becomes long, and large stress tends to act on the tire side portions. Therefore, by employing the above configuration in a small diameter tire, the effect of improving the ground contact performance and durability performance of the tire can be significantly obtained.
また、図11において、上記円弧の曲率半径RP[mm]が、タイヤ断面幅DW[mm]およびタイヤ断面高さSH[mm]に対して60≦RP/(SH/DW)≦290の範囲にあり、好ましくは150≦RP/(SH/DW)≦250の範囲にある。これにより、上記円弧の曲率半径RPがタイヤ1の偏平比SH/DWに対して適正化される。具体的に、上記下限により、タイヤ転動時におけるタイヤ径方向外側領域の撓み量が低減されて、タイヤの接地性能が確保される。上記上限により、タイヤ径方向外側領域における応力集中が緩和されて、タイヤの耐久性能が向上する。
In addition, in FIG. 11, the radius of curvature RP [mm] of the circular arc is in the range of 60≦RP/(SH/DW)≦290 with respect to the tire cross-sectional width DW [mm] and the tire cross-sectional height SH [mm]. It is preferably in the range of 150≦RP/(SH/DW)≦250. Thereby, the radius of curvature RP of the circular arc is optimized with respect to the aspect ratio SH/DW of the tire 1. Specifically, the above lower limit reduces the amount of deflection of the radially outer region of the tire when the tire rolls, thereby ensuring the ground contact performance of the tire. With the above upper limit, stress concentration in the tire radially outer region is alleviated, and the tire durability performance is improved.
また、図11において、タイヤを規定リムに装着して規定内圧を付与すると共に規定荷重の100[%]の荷重を付与したときの前記円弧の曲率半径RP’[mm](図中の寸法記号省略)を定義する。すなわち、上記した無負荷状態にてタイヤ最大幅位置Ac、点Au’および点Anを定義し、その後に、規定荷重の100[%]の荷重の付与により変位した3点Ac、Au’およびAn(図示省略)を通る円弧の曲率半径RP’[mm]を定義する。このとき、上記した無負荷状態における円弧の曲率半径RP’[mm]が、規定荷重の100[%]負荷時における円弧の曲率半径RP’[mm]に対して1.10≦RP/RP’≦2.80の範囲にあり、好ましくは1.15≦RP/RP’≦2.60の範囲にある。これにより、100[%]荷重付与時における曲率半径RP’が適正化される。具体的に、上記下限により、荷重付与時、すなわち荷重増加時におけるタイヤ径方向外側領域の撓み量が確保されて、タイヤ径方向外側領域における応力集中が緩和される。上記上限により、タイヤ転動時におけるタイヤ径方向外側領域の撓み量が低減されて、タイヤの接地性能が確保される。
In addition, in Fig. 11, the radius of curvature RP' [mm] of the circular arc when the tire is mounted on a specified rim, a specified internal pressure is applied, and a load of 100 [%] of the specified load is applied (dimension symbol in the figure). (omitted). That is, the tire maximum width position Ac, point Au', and point An are defined in the above-mentioned no-load state, and then the three points Ac, Au', and An are displaced by applying a load of 100% of the specified load. The radius of curvature RP' [mm] of a circular arc passing through (not shown) is defined. At this time, the radius of curvature RP' [mm] of the arc in the above-mentioned no-load state is 1.10≦RP/RP' with respect to the radius of curvature RP' [mm] of the arc under 100 [%] of the specified load. It is in the range of ≦2.80, preferably in the range of 1.15≦RP/RP'≦2.60. As a result, the radius of curvature RP' when applying a 100[%] load is optimized. Specifically, the above lower limit ensures the amount of deflection of the radially outer region of the tire when a load is applied, that is, when the load increases, and the stress concentration in the radially outer region of the tire is alleviated. The above upper limit reduces the amount of deflection of the radially outer region of the tire when the tire rolls, thereby ensuring the ground contact performance of the tire.
また、図11において、タイヤを規定リムに装着して規定内圧を付与すると共に規定荷重の150[%]の荷重を付与したときの前記円弧の曲率半径RP”[mm](図中の寸法記号省略)を定義する。すなわち、規定荷重の150[%]の荷重の付与により変位した3点Ac、Au’およびAn(図示省略)を通る円弧の曲率半径RP”[mm]を定義する。このとき、上記した100[%]の荷重を付与したときの前記円弧の曲率半径RP’[mm]が、規定荷重の150[%]の荷重を付与したときの前記円弧の曲率半径RP”[mm]に対して1.01≦RP’/RP”≦1.50の範囲にあり、好ましくは1.05≦RP’/RP”≦1.30の範囲にある。これにより、150[%]荷重付与時、すなわち高負荷時における曲率半径RP”が適正化される。具体的に、上記下限により、高負荷での使用時におけるタイヤ径方向外側領域の撓み量が確保されて、タイヤ径方向外側領域における応力集中が緩和される。上記上限により、タイヤ転動時におけるタイヤ径方向外側領域の撓み量、すなわち繰り返し変形量が低減されて、タイヤの接地性能が確保される。
In addition, in Fig. 11, the radius of curvature RP'' [mm] of the circular arc when the tire is mounted on a specified rim, a specified internal pressure is applied, and a load of 150 [%] of the specified load is applied (dimension symbol in the figure). In other words, the radius of curvature RP'' [mm] of an arc passing through the three points Ac, Au', and An (not shown) displaced by the application of a load of 150% of the specified load is defined. At this time, the radius of curvature RP' [mm] of the arc when a load of 100 [%] is applied is the radius of curvature RP' [mm] of the arc when a load of 150 [%] of the specified load is applied. mm] is in the range of 1.01≦RP'/RP''≦1.50, preferably in the range of 1.05≦RP'/RP''≦1.30.Thereby, 150[%] The radius of curvature RP" when a load is applied, that is, when a high load is applied, is optimized. Specifically, the above lower limit ensures the amount of deflection of the radially outer region of the tire during use under high load, thereby relieving stress concentration in the radially outer region of the tire. The above upper limit reduces the amount of deflection of the tire radially outer region during tire rolling, that is, the amount of repeated deformation, and ensures the ground contact performance of the tire.
また、上記のように、ベルト層14が、相互に異符号のコード角度を有する一対の交差ベルト141、142を備える(図3参照)。また、一対の交差ベルト141、142のコード角度Bθ(Bθ1、Bθ2)が、絶対値で15[deg]以上55[deg]以下の範囲にあり、好ましくは15[deg]以上35[deg]以下の範囲にある。このとき、一対の交差ベルト141、142のコード角度Bθ[deg]のそれぞれが、上記したタイヤ径方向外側領域の円弧の曲率半径RP[mm]に対して1000≦Bθ×RP≦7700の範囲にあり、好ましくは1200≦Bθ×RP≦7500の範囲にある。これにより、積Bθ×RPが適正化される。具体的に、積Bθ×RPの下限により、トレッド部ショルダー領域の接地長が過長となることが抑制され、タイヤの接地性能(特に騒音性能)が確保される。積Bθ×RPの上限により、交差ベルト141、142によるタガ効果が確保され、また、タイヤ径方向外側領域の応力集中が緩和されて、タイヤの耐久性能が向上する。
Furthermore, as described above, the belt layer 14 includes a pair of intersecting belts 141 and 142 having cord angles of opposite signs (see FIG. 3). Further, the cord angle Bθ (Bθ1, Bθ2) of the pair of crossing belts 141 and 142 is in the range of 15 [deg] or more and 55 [deg] or less in absolute value, preferably 15 [deg] or more and 35 [deg] or less. within the range of At this time, each of the cord angles Bθ [deg] of the pair of crossing belts 141 and 142 is in the range of 1000≦Bθ×RP≦7700 with respect to the radius of curvature RP [mm] of the circular arc of the tire radial direction outer region. It is preferably in the range of 1200≦Bθ×RP≦7500. As a result, the product Bθ×RP is optimized. Specifically, the lower limit of the product Bθ×RP prevents the ground contact length of the tread shoulder region from becoming excessively long, and ensures the ground contact performance (especially noise performance) of the tire. The upper limit of the product Bθ×RP ensures the hoop effect of the intersecting belts 141 and 142, and also relieves stress concentration in the tire radially outer region, improving tire durability.
図12は、図11に記載したタイヤ径方向外側領域におけるカーカス層13およびインナーライナ18の積層構造を示す説明図である。
FIG. 12 is an explanatory diagram showing the laminated structure of the carcass layer 13 and the inner liner 18 in the radially outer region of the tire shown in FIG. 11.
図11において、ベルト層14の最内層141の端部に対してタイヤ径方向の同位置にあるサイドプロファイル上の点Auからカーカス層13に下した垂線の足を点Iuとして定義する。また、タイヤ最大幅位置Acからカーカス層13に下した垂線の足を点Icとして定義する。図11に示すように、点Iuおよい点Icは、上記したトータルゲージGu、Gcのそれぞれの測定位置に一致する。
In FIG. 11, the foot of a perpendicular line drawn from a point Au on the side profile at the same position in the tire radial direction to the end of the innermost layer 141 of the belt layer 14 to the carcass layer 13 is defined as a point Iu. Further, the foot of a perpendicular line drawn from the tire maximum width position Ac to the carcass layer 13 is defined as a point Ic. As shown in FIG. 11, point Iu and point Ic correspond to the respective measurement positions of the total gauges Gu and Gc described above.
図12において、上記のように、カーカス層13がカーカスコード13ccをコートゴム13crで被覆して成る。また、図12の構成では、カーカス層13が単一層のカーカスプライ13Aから成る。しかし、これに限らず、カーカス層13が複数層のカーカスプライから構成されても良い(図9参照)。
In FIG. 12, as described above, the carcass layer 13 is formed by covering the carcass cord 13cc with the coat rubber 13cr. Furthermore, in the configuration of FIG. 12, the carcass layer 13 is composed of a single layer carcass ply 13A. However, the present invention is not limited to this, and the carcass layer 13 may be composed of a plurality of carcass plies (see FIG. 9).
このとき、図11の点Iuから点Icまでの領域におけるカーカスプライ13A(カーカス層13が2層のカーカスプライを積層して成る構成(図示省略)では、最内層のカーカスプライ)の最内層13Aのカーカスコード13ccの中心からタイヤ内面までの距離TLu[mm](図12参照)が、タイヤ外径OD[mm](図1参照)に対して0.00010≦TLu/OD≦0.01500の範囲にあり、好ましくは0.00015≦TLu/OD≦0.01200の範囲にある。具体的に、例えば、インナーライナ18がブチルゴムを主成分とするゴム組成物から成る構成では、比TLu/ODが0.00090≦TLu/OD≦0.01500の範囲にあり、好ましくは0.00100≦TLu/OD≦0.01200の範囲にある。また、インナーライナ18が熱可塑性樹脂あるいは熱可塑性樹脂中にエラストマー成分をブレンドした熱可塑性エラストマー組成物から成る構成では、比TLu/ODが0.00010≦TLu/OD≦0.00200の範囲にあり、好ましくは0.00015≦TLu/OD≦0.00100の範囲にある。
At this time, the innermost layer 13A of the carcass ply 13A (the innermost carcass ply in the structure in which the carcass layer 13 is formed by laminating two carcass plies (not shown)) in the region from point Iu to point Ic in FIG. The distance TLu [mm] (see Fig. 12) from the center of the carcass cord 13cc to the inner surface of the tire is 0.00010≦TLu/OD≦0.01500 with respect to the tire outer diameter OD [mm] (see Fig. 1). It is preferably in the range of 0.00015≦TLu/OD≦0.01200. Specifically, for example, in a configuration in which the inner liner 18 is made of a rubber composition containing butyl rubber as a main component, the ratio TLu/OD is in the range of 0.00090≦TLu/OD≦0.01500, preferably 0.00100. It is in the range of ≦TLu/OD≦0.01200. Further, when the inner liner 18 is made of a thermoplastic resin or a thermoplastic elastomer composition obtained by blending an elastomer component into a thermoplastic resin, the ratio TLu/OD is in the range of 0.00010≦TLu/OD≦0.00200. , preferably in the range of 0.00015≦TLu/OD≦0.00100.
上記の構成では、ベルト層14の端部からタイヤ最大幅位置Acまでの領域におけるカーカス層13からタイヤ内面までの距離TLuが適正化される。具体的に、上記下限により、エア漏れが発生し易い上記領域におけるカーカス層13からタイヤ内面までの距離TLuが確保されて、エア漏れに起因するタイヤの耐久性能の低下や転がり抵抗の悪化が抑制される。また、上記上限により、タイヤ重量の増加に起因する転がり抵抗の悪化が抑制される。これにより、タイヤの耐久性能および低転がり抵抗性能が両立する。特に小径タイヤでは、上記した高内圧および高負荷で使用されるため、応力集中が起きやすい傾向にある。したがって、上記構成が小径タイヤに採用されることで、タイヤの耐久性能および低転がり抵抗性能の向上作用が顕著に得られる。
In the above configuration, the distance TLu from the carcass layer 13 to the inner surface of the tire in the region from the end of the belt layer 14 to the tire maximum width position Ac is optimized. Specifically, the lower limit ensures the distance TLu from the carcass layer 13 to the inner surface of the tire in the region where air leakage is likely to occur, thereby suppressing a decrease in tire durability performance and deterioration of rolling resistance due to air leakage. be done. Further, the above upper limit suppresses deterioration of rolling resistance due to an increase in tire weight. This achieves both tire durability and low rolling resistance. In particular, small-diameter tires are used under the above-mentioned high internal pressure and high load, so stress concentration tends to occur easily. Therefore, when the above configuration is adopted for a small diameter tire, the durability performance and low rolling resistance performance of the tire can be significantly improved.
また、図11の点Iuから点Icまでの領域における距離TLu[mm](図12参照)の最小値TLu_minおよび最大値TLu_maxが、0.30≦TLu_min/TLu_max≦1.00の関係を有し、好ましくは、0.40≦TLu_min/TLu_max≦1.00の関係を有する。かかる構成では、カーカスコード13ccからタイヤ内面までの距離TLuが上記領域にて均一に設定されるので、距離TLuの不均一さに起因するタイヤ故障が抑制されて、エア漏れの発生リスクが低減される。また、距離TLu[mm]が、0.1≦TLu≦4.0の範囲にあり、好ましくは0.5≦TLu≦3.5の範囲にある。上記下限により、カーカスコード13ccからタイヤ内面までの距離TLuが確保されて、エア漏れが適正に抑制され、上記上限により、タイヤ重量の増加に起因する転がり抵抗の悪化が抑制される。
Further, the minimum value TLu_min and maximum value TLu_max of the distance TLu [mm] (see FIG. 12) in the area from point Iu to point Ic in FIG. 11 have a relationship of 0.30≦TLu_min/TLu_max≦1.00. , preferably has a relationship of 0.40≦TLu_min/TLu_max≦1.00. In this configuration, since the distance TLu from the carcass cord 13cc to the inner surface of the tire is set uniformly in the above region, tire failure due to non-uniformity of the distance TLu is suppressed, and the risk of air leakage is reduced. Ru. Further, the distance TLu [mm] is in the range of 0.1≦TLu≦4.0, preferably in the range of 0.5≦TLu≦3.5. The lower limit ensures a distance TLu from the carcass cord 13cc to the inner surface of the tire, and air leakage is appropriately suppressed, and the upper limit suppresses deterioration of rolling resistance due to increase in tire weight.
例えば、図11の構成では、TLu_min/TLu_max<1.00であり、距離TLuが最大値TLu_maxをとる位置が、最小値TLu_minをとる位置よりも点Ic側(すなわちタイヤ最大幅位置Ac側)に位置する。また、最大値TLu_maxをとる位置が、図11における点Icから距離Huの35[%]までの領域(すなわち点Acから点Anまでの領域)にある。また、最小値TLu_minをとる位置が、図11における点Iuから距離Huの35[%]までの領域にある。さらに、距離TLuが、最小値TLu_minをとる位置から最大値TLu_maxをとる位置に向かって単調増加する。
For example, in the configuration of FIG. 11, TLu_min/TLu_max<1.00, and the position where the distance TLu takes the maximum value TLu_max is closer to the point Ic (that is, the tire maximum width position Ac side) than the position where the distance TLu takes the minimum value TLu_min. To position. Further, the position where the maximum value TLu_max is taken is in the region from point Ic to 35% of the distance Hu in FIG. 11 (that is, the region from point Ac to point An). Further, the position where the minimum value TLu_min is taken is in the area from the point Iu to 35% of the distance Hu in FIG. Further, the distance TLu monotonically increases from the position where the minimum value TLu_min is taken to the position where the maximum value TLu_max is taken.
また、図11の点Iuから点Icまでの領域におけるタイヤサイド部のトータルゲージGa[mm]の最小値Ga_min(図11参照)と、同位置における上記距離TLuに相当する距離TLu’[mm](図中の寸法記号省略)とが、0.05≦TLu’/Ga_minの関係を有し、好ましくは0.10≦TLu’/Ga_minの関係を有する(図12参照)。これにより、トータルゲージGaが薄い位置におけるカーカスコード13ccからタイヤ内面までの距離TLu’が確保されて、エア漏れが適正に抑制される。図11の構成では、タイヤサイド部のトータルゲージGaがタイヤ最大幅位置Acで最小となり、したがって、最小値Ga_minがトータルゲージGcに一致している。また、距離TLu’が、トータルゲージGaが最小値Ga_minをとるタイヤ最大幅位置Acで測定される。なお、比TLu’/Ga_minの上限は特に限定がないが、距離TLuの上限により制約を受ける。
Furthermore, the minimum value Ga_min (see FIG. 11) of the total gauge Ga [mm] of the tire side part in the area from point Iu to point Ic in FIG. 11, and the distance TLu' [mm] corresponding to the above distance TLu at the same position. (dimension symbols omitted in the figure) have a relationship of 0.05≦TLu'/Ga_min, preferably a relationship of 0.10≦TLu'/Ga_min (see FIG. 12). As a result, the distance TLu' from the carcass cord 13cc to the inner surface of the tire at the position where the total gauge Ga is thin is ensured, and air leakage is appropriately suppressed. In the configuration of FIG. 11, the total gauge Ga at the tire side portion becomes the minimum at the tire maximum width position Ac, and therefore the minimum value Ga_min matches the total gauge Gc. Further, the distance TLu' is measured at the tire maximum width position Ac where the total gauge Ga takes the minimum value Ga_min. Note that the upper limit of the ratio TLu'/Ga_min is not particularly limited, but is restricted by the upper limit of the distance TLu.
また、図11の点Iuから点Icまでの領域におけるタイヤサイド部のトータルゲージGa[mm]の最小値Ga_minと、同位置における上記距離TLuに相当する距離TLu’[mm]とが、タイヤ外径OD[mm]に対して0.005≦(Ga_min+TLu’)/OD≦0.040の範囲にあり、好ましくは0.006≦(Ga_min+TLu’)/OD≦0.030の範囲にある。上記下限により、エア漏れが適正に抑制され、上記上限により、タイヤ重量の増加が抑制される。
Moreover, the minimum value Ga_min of the total gauge Ga [mm] of the tire side part in the area from point Iu to point Ic in FIG. 11 and the distance TLu' [mm] corresponding to the above distance TLu at the same position are outside the tire. The diameter OD [mm] is in the range of 0.005≦(Ga_min+TLu')/OD≦0.040, preferably in the range of 0.006≦(Ga_min+TLu')/OD≦0.030. The above lower limit appropriately suppresses air leakage, and the above upper limit suppresses an increase in tire weight.
また、図11の点Iuから点Icまでの領域における距離TLu[mm]が、インナーライナ18の酸素透過係数α[mm・cc/(m^2・day・mmHg)]に対して0.005≦(α^(1/2))/TLu≦1.800の関係を有し、好ましくは0.008≦(α^(1/2))/TLu≦1.500の関係を有する。また、インナーライナ18の酸素透過係数αが、0.0008≦α≦0.3500の範囲にあり、0.0010≦α≦0.3000の範囲にあることが好ましい。これにより、インナーライナ18の耐クラック性を確保しつつ、エア漏れに対する内圧保持性を向上できる。
Moreover, the distance TLu [mm] in the region from point Iu to point Ic in FIG. 11 is 0.005 with respect to the oxygen permeability coefficient α [mm・cc/(m^2・day・mmHg)] The relationship is ≦(α^(1/2))/TLu≦1.800, preferably 0.008≦(α^(1/2))/TLu≦1.500. Further, the oxygen permeability coefficient α of the inner liner 18 is in the range of 0.0008≦α≦0.3500, and preferably in the range of 0.0010≦α≦0.3000. Thereby, while ensuring the crack resistance of the inner liner 18, it is possible to improve the internal pressure retention property against air leakage.
酸素透過係数αは、インナーライナ18を構成する素材がどの程度酸素を透過するかを示す指標であであり、JIS K 7126に準拠して相対温度21[℃]および相対湿度50[%]にて測定される。
The oxygen permeability coefficient α is an index that indicates how much oxygen permeates through the material constituting the inner liner 18, and is based on JIS K 7126 at a relative temperature of 21 [°C] and a relative humidity of 50 [%]. measured.
また、インナーライナ18の動的貯蔵弾性率β[MPa]が、1≦β≦200の範囲にあり、2≦β≦150の範囲にあることが好ましい。これにより、インナーライナ18の耐クラック性を確保しつつ、エア漏れに対する内圧保持性を向上できる。
Furthermore, the dynamic storage elastic modulus β [MPa] of the inner liner 18 is in the range of 1≦β≦200, and preferably in the range of 2≦β≦150. Thereby, while ensuring the crack resistance of the inner liner 18, it is possible to improve the internal pressure retention property against air leakage.
動的貯蔵弾性率βは、幅5mm、長さ60mmの短冊状に切り出した試験片にて、東洋精機製作所製の粘弾性スペクトロメーターを用いて、静的歪み5%、動的歪み±0.1%、周波数20Hzおよび温度60℃の条件で測定される。
The dynamic storage elastic modulus β was measured using a viscoelastic spectrometer manufactured by Toyo Seiki Co., Ltd. using a test piece cut into a rectangular shape with a width of 5 mm and a length of 60 mm, at a static strain of 5% and a dynamic strain of ±0. 1%, a frequency of 20 Hz, and a temperature of 60°C.
また、インナーライナ18では、エア漏れを抑制するために、その構成部材の端部が相互にオーバーラップするように接続される。このとき、図11の点Iuから点Icまでの領域におけるインナーライナ18のスプライス量Is[mm](図示省略)、すなわち構成部材の端部のオーバーラップ幅が、タイヤ外径OD[mm]に対して0.010≦Is/OD≦0.100の範囲にあり、好ましくは0.015≦Is/OD≦0.080の範囲にある。また、インナーライナ18のスプライス量Is[mm]が、8≦Is≦20の範囲にある。上記下限により、エア漏れが適正に抑制され、上記上限により、タイヤ重量の増加に起因する転がり抵抗の悪化が抑制される。
Additionally, in the inner liner 18, the ends of its constituent members are connected so as to overlap each other in order to suppress air leakage. At this time, the splice amount Is [mm] (not shown) of the inner liner 18 in the region from point Iu to point Ic in FIG. On the other hand, it is in the range of 0.010≦Is/OD≦0.100, preferably in the range of 0.015≦Is/OD≦0.080. Further, the splice amount Is [mm] of the inner liner 18 is in the range of 8≦Is≦20. The above lower limit appropriately suppresses air leakage, and the above upper limit suppresses deterioration of rolling resistance due to an increase in tire weight.
また、図4において、上記のように、左右のタイヤ接地端T,Tからカーカス層13に下した垂線の足のそれぞれを点B2、B2として定義する。また、点B2、B2の間の領域におけるカーカスプライの最内層13Aのカーカスコード13ccの中心からタイヤ内面までの距離TL[mm](図8参照)の最小値TL_minを定義する。
In addition, in FIG. 4, as described above, the legs of the perpendicular line drawn from the left and right tire ground contact ends T, T to the carcass layer 13 are defined as points B2, B2, respectively. Furthermore, the minimum value TL_min of the distance TL [mm] (see FIG. 8) from the center of the carcass cord 13cc of the innermost layer 13A of the carcass ply to the inner surface of the tire in the area between points B2 and B2 is defined.
このとき、図11の点Iuから点Icまでの領域における距離TLu[mm](図12参照)の最小値TLu_minが、図4の点B2、B2の間の領域における距離TL[mm]の最小値TL_minに対して1.00≦TLu_min/TL_minの範囲にあり、好ましくは1.05≦TLu_min/TL_minの範囲にある。したがって、カーカスプライからタイヤ内面までの距離が、エア漏れが発生し易い領域にて相対的に薄くならないように、点Iuから点Icまでの領域における距離TLuが設定される。これにより、エア漏れが発生し易い点Iuから点Icまでの前記領域におけるカーカスプライからタイヤ内面までの距離TLが相対的に確保されて、エア漏れが効果的に抑制される。
At this time, the minimum value TLu_min of the distance TLu [mm] (see FIG. 12) in the region from point Iu to point Ic in FIG. 11 is the minimum value TLu_min of the distance TL [mm] in the region between points B2 and B2 in FIG. The value TL_min is in the range of 1.00≦TLu_min/TL_min, preferably in the range of 1.05≦TLu_min/TL_min. Therefore, the distance TLu in the region from point Iu to point Ic is set so that the distance from the carcass ply to the inner surface of the tire does not become relatively thin in the region where air leakage is likely to occur. As a result, the distance TL from the carcass ply to the inner surface of the tire in the region from point Iu to point Ic where air leakage is likely to occur is relatively secured, and air leakage is effectively suppressed.
[効果]
以上説明したように、[1]このタイヤ1は、一対のビードコア11、11と、ビードコア11、11に架け渡されたカーカス層13と、カーカス層13の径方向外側に配置されたベルト層14とを備える(図1参照)。また、タイヤ外径OD[mm]が、200≦OD≦660の範囲にあり、タイヤ総幅SW[mm]が、100≦SW≦400の範囲にある。また、タイヤ子午線方向の断面視にて、ベルト層14の最内層141の端部に対してタイヤ径方向の同位置にあるサイドプロファイル上の点Auを定義する。また、点Auからカーカス層13に下した垂線の足を点Iuとして定義し、タイヤ最大幅位置Acから前記カーカス層に下した垂線の足を点Icとして定義する。また、カーカス層13が、カーカスコード13ccをコートゴム13crで被覆して成る単一層(図8参照)あるいは複数層(図9参照)のカーカスプライから構成される。また、点Iuから点Icまでの領域におけるカーカスプライの最内層13Aのカーカスコード13ccの中心からタイヤ内面までの距離TLu[mm](図12参照)が、タイヤ外径OD[mm](図1参照)に対して0.00010≦TLu/OD≦0.01500の範囲にある。 [effect]
As explained above, [1] Thistire 1 includes a pair of bead cores 11, 11, a carcass layer 13 spanning the bead cores 11, 11, and a belt layer 14 disposed on the radially outer side of the carcass layer 13. (See Figure 1). Further, the tire outer diameter OD [mm] is in the range of 200≦OD≦660, and the tire total width SW [mm] is in the range of 100≦SW≦400. Further, in a cross-sectional view in the tire meridian direction, a point Au on the side profile is defined at the same position in the tire radial direction with respect to the end of the innermost layer 141 of the belt layer 14. Further, the foot of the perpendicular line drawn from point Au to the carcass layer 13 is defined as point Iu, and the foot of the perpendicular line drawn from the tire maximum width position Ac to the carcass layer is defined as point Ic. Further, the carcass layer 13 is composed of a single layer (see FIG. 8) or a plurality of layers (see FIG. 9) of carcass ply, which is formed by covering a carcass cord 13cc with a coating rubber 13cr. Further, the distance TLu [mm] (see Fig. 12) from the center of the carcass cord 13cc of the innermost layer 13A of the carcass ply to the inner surface of the tire in the region from point Iu to point Ic is the tire outer diameter OD [mm] (see Fig. 1 ) is in the range of 0.00010≦TLu/OD≦0.01500.
以上説明したように、[1]このタイヤ1は、一対のビードコア11、11と、ビードコア11、11に架け渡されたカーカス層13と、カーカス層13の径方向外側に配置されたベルト層14とを備える(図1参照)。また、タイヤ外径OD[mm]が、200≦OD≦660の範囲にあり、タイヤ総幅SW[mm]が、100≦SW≦400の範囲にある。また、タイヤ子午線方向の断面視にて、ベルト層14の最内層141の端部に対してタイヤ径方向の同位置にあるサイドプロファイル上の点Auを定義する。また、点Auからカーカス層13に下した垂線の足を点Iuとして定義し、タイヤ最大幅位置Acから前記カーカス層に下した垂線の足を点Icとして定義する。また、カーカス層13が、カーカスコード13ccをコートゴム13crで被覆して成る単一層(図8参照)あるいは複数層(図9参照)のカーカスプライから構成される。また、点Iuから点Icまでの領域におけるカーカスプライの最内層13Aのカーカスコード13ccの中心からタイヤ内面までの距離TLu[mm](図12参照)が、タイヤ外径OD[mm](図1参照)に対して0.00010≦TLu/OD≦0.01500の範囲にある。 [effect]
As explained above, [1] This
かかる構成では、ベルト層14の端部からタイヤ最大幅位置Acまでの領域におけるカーカス層13からタイヤ内面までの距離TLuが適正化される利点がある。具体的に、上記下限により、エア漏れが発生し易い上記領域におけるカーカス層13からタイヤ内面までの距離TLuが確保されて、エア漏れに起因するタイヤの耐久性能の低下や転がり抵抗の悪化が抑制される。また、上記上限により、タイヤ重量の増加に起因する転がり抵抗の悪化が抑制される。これにより、タイヤの耐久性能および低転がり抵抗性能が両立する。特に小径タイヤでは、上記した高内圧および高負荷で使用されるため、応力集中が起きやすい傾向にある。したがって、上記構成が小径タイヤに採用されることで、タイヤの耐久性能および低転がり抵抗性能の向上作用が顕著に得られる。
This configuration has the advantage that the distance TLu from the carcass layer 13 to the inner surface of the tire in the region from the end of the belt layer 14 to the tire maximum width position Ac is optimized. Specifically, the lower limit ensures the distance TLu from the carcass layer 13 to the inner surface of the tire in the region where air leakage is likely to occur, thereby suppressing a decrease in tire durability performance and deterioration of rolling resistance due to air leakage. be done. Further, the above upper limit suppresses deterioration of rolling resistance due to an increase in tire weight. This achieves both tire durability and low rolling resistance. In particular, small-diameter tires are used under the above-mentioned high internal pressure and high load, so stress concentration tends to occur easily. Therefore, when the above configuration is adopted for a small diameter tire, the durability performance and low rolling resistance performance of the tire can be significantly improved.
また、[2]このタイヤ1では、上記[1]に記載のタイヤ1において、点Iuから点Icまでの前記領域における距離TLu[mm](図12参照)の最小値TLu_minおよび最大値TLu_maxが、0.30≦TLu_min/TLu_max≦1.00の関係を有する。かかる構成では、カーカスコード13ccからタイヤ内面までの距離TLuが上記領域にて均一に設定されるので、距離TLuの不均一さに起因するタイヤ故障が抑制されて、エア漏れの発生リスクが低減される利点がある。
[2] In this tire 1, in the tire 1 described in [1] above, the minimum value TLu_min and maximum value TLu_max of the distance TLu [mm] (see FIG. 12) in the area from point Iu to point Ic are , 0.30≦TLu_min/TLu_max≦1.00. In this configuration, since the distance TLu from the carcass cord 13cc to the inner surface of the tire is set uniformly in the above region, tire failure due to non-uniformity of the distance TLu is suppressed, and the risk of air leakage is reduced. It has the advantage of
また、[3]このタイヤ1では、上記[1]または[2]に記載のタイヤ1において、点Iuから点Icまでの前記領域における距離TLu[mm]が、0.1≦TLu≦4.0の範囲にある。上記下限により、カーカスコード13ccからタイヤ内面までの距離TLuが確保されて、エア漏れが適正に抑制され、上記上限により、タイヤ重量の増加に起因する転がり抵抗の悪化が抑制される利点がある。
[3] In this tire 1, in the tire 1 described in [1] or [2] above, the distance TLu [mm] in the region from point Iu to point Ic is 0.1≦TLu≦4. It is in the range of 0. The above lower limit has the advantage that the distance TLu from the carcass cord 13cc to the inner surface of the tire is ensured, and air leakage is appropriately suppressed, and the above upper limit suppresses deterioration of rolling resistance due to an increase in tire weight.
また、[4]このタイヤ1では、上記[1]~[3]のいずれか一つに記載のタイヤ1において、点Iuから点Icまでの前記領域におけるタイヤサイド部のトータルゲージGa[mm](図11参照)と、同位置における上記距離TLuに相当する距離TLu’[mm]とが、0.05≦TLu’/Ga_minの関係を有る(図12参照)。これにより、トータルゲージGaが薄い位置におけるカーカスコード13ccからタイヤ内面までの距離TLu’が確保されて、エア漏れが適正に抑制される利点がある。
[4] In this tire 1, in the tire 1 according to any one of [1] to [3] above, the total gauge Ga [mm] of the tire side portion in the area from point Iu to point Ic is (see FIG. 11) and a distance TLu' [mm] corresponding to the distance TLu at the same position have a relationship of 0.05≦TLu'/Ga_min (see FIG. 12). This has the advantage that the distance TLu' from the carcass cord 13cc to the inner surface of the tire at the position where the total gauge Ga is thin is ensured, and air leakage is appropriately suppressed.
また、[5]このタイヤ1では、上記[1]~[4]のいずれか一つに記載のタイヤ1において、点Iuから点Icまでの前記領域における距離TLu[mm]が、インナーライナ18の酸素透過係数α[mm・cc/(m^2・day・mmHg)]に対して0.005≦(α^(1/2))/TLu≦1.800の関係を有する。これにより、インナーライナ18の耐クラック性を確保しつつ、エア漏れに対する内圧保持性を向上できる利点がある。
[5] In this tire 1, in the tire 1 described in any one of [1] to [4] above, the distance TLu [mm] in the region from point Iu to point Ic is It has a relationship of 0.005≦(α^(1/2))/TLu≦1.800 for the oxygen permeability coefficient α [mm·cc/(m^2·day·mmHg)]. This has the advantage of ensuring crack resistance of the inner liner 18 and improving internal pressure retention against air leakage.
また、[6]このタイヤ1では、上記[1]~[5]のいずれか一つに記載のタイヤ1において、点Iuから点Icまでの前記領域におけるインナーライナ18のスプライス量Is[mm](図示省略)が、タイヤ外径OD[mm]に対して0.01≦Is/OD≦0.10の範囲にある。上記下限により、エア漏れが適正に抑制され、上記上限により、タイヤ重量の増加に起因する転がり抵抗の悪化が抑制される利点がある。
[6] In this tire 1, in the tire 1 described in any one of the above [1] to [5], the splice amount Is [mm] of the inner liner 18 in the region from point Iu to point Ic is (not shown) is in the range of 0.01≦Is/OD≦0.10 with respect to the tire outer diameter OD [mm]. The above lower limit has the advantage of appropriately suppressing air leakage, and the above upper limit has the advantage of suppressing deterioration of rolling resistance due to an increase in tire weight.
また、[7]このタイヤ1では、上記[1]~[6]のいずれか一つに記載のタイヤ1において、左右のタイヤ接地端T、Tからカーカス層13に下した垂線の足のそれぞれを点B2、B2として定義する(図4参照)。また、点Iuから点Icまでの前記領域における距離TLu[mm](図12参照)の最小値TLu_minが、点B2、B2の間の領域におけるカーカスプライの最内層13Aのカーカスコード13crcの中心からタイヤ内面までの距離TL[mm](図8参照)の最小値TL_minに対して1.00≦TLu_min/TL_minの範囲にある。これにより、エア漏れが発生し易い点Iuから点Icまでの前記領域におけるカーカスプライからタイヤ内面までの距離TLが相対的に確保されて、エア漏れが効果的に抑制される利点がある。
[7] In this tire 1, in the tire 1 described in any one of the above [1] to [6], each of the legs of the perpendicular line drawn from the left and right tire ground contact ends T, T to the carcass layer 13 are defined as points B2 and B2 (see FIG. 4). Moreover, the minimum value TLu_min of the distance TLu [mm] (see FIG. 12) in the region from point Iu to point Ic is from the center of the carcass cord 13crc of the innermost layer 13A of the carcass ply in the region between points B2 and B2. The minimum value TL_min of the distance TL [mm] (see FIG. 8) to the inner surface of the tire is in the range of 1.00≦TLu_min/TL_min. This has the advantage that the distance TL from the carcass ply to the inner surface of the tire in the region from point Iu to point Ic where air leakage is likely to occur is relatively secured, and air leakage is effectively suppressed.
また、[8]このタイヤ1では、上記[1]~[7]のいずれか一つに記載のタイヤ1において、カーカス層13を構成するカーカスプライの幅50[mm]あたりの強力Tcs[N/50mm]が、タイヤ外径OD[mm]に対して17≦Tcs/OD≦120の範囲にある。かかる構成では、小径タイヤにおいてカーカス層13の負荷能力が適正に確保されるので、タイヤの耐久性能および低転がり抵抗性能が両立する利点がある。具体的に、上記下限により、高負荷での使用時におけるタイヤ変形が抑制されて、タイヤの耐久性能が確保される。また、高内圧での使用が可能となり、タイヤの転がり抵抗が低減される。特に小径タイヤでは、高内圧および高負荷での使用が想定されるため、上記したタイヤの耐久性能および転がり抵抗の低減作用が顕著に得られる。上記上限により、カーカス層の質量増加に起因する転がり抵抗の悪化が抑制される。
[8] In this tire 1, in the tire 1 according to any one of [1] to [7] above, the strength Tcs [N /50mm] is in the range of 17≦Tcs/OD≦120 with respect to the tire outer diameter OD [mm]. In such a configuration, since the load capacity of the carcass layer 13 is appropriately ensured in a small-diameter tire, there is an advantage that the tire has both durability performance and low rolling resistance performance. Specifically, the above lower limit suppresses tire deformation during use under high loads and ensures tire durability. In addition, it becomes possible to use the tire at high internal pressure, and the rolling resistance of the tire is reduced. In particular, small-diameter tires are expected to be used under high internal pressure and high loads, so the above-described tire durability and rolling resistance reduction effect can be significantly achieved. The above upper limit suppresses deterioration of rolling resistance due to increase in mass of the carcass layer.
また、[9]このタイヤ1では、上記[8]に記載のタイヤ1において、カーカス層13のカーカスプライが、スチールから成るカーカスコードをコートゴムで被覆して構成される。また、カーカスコードのコード径φcs[mm]が、0.15≦φcs≦1.10の範囲にある。また、カーカスコードの打ち込み本数Ecs[本/50mm]が、25≦Ecs≦80の範囲にある。これにより、上記したカーカス層13の強力Tcsが実現される利点がある。
[9] In this tire 1, in the tire 1 described in [8] above, the carcass ply of the carcass layer 13 is constructed by covering a carcass cord made of steel with a coated rubber. Further, the cord diameter φcs [mm] of the carcass cord is in the range of 0.15≦φcs≦1.10. Further, the number of carcass cords driven in Ecs [pieces/50 mm] is in the range of 25≦Ecs≦80. This has the advantage of realizing the strong Tcs of the carcass layer 13 described above.
また、[10]このタイヤ1では、上記[9]に記載のタイヤ1において、カーカスコードが、複数の素線を撚り合わせて成り、且つ、カーカスコードの素線径φcss[mm]が、カーカスコードのコード径φcs[mm]に対して0.30≦φcss/φcs≦0.90の範囲にある。これにより、上記したカーカス層13の強力Tcsが実現される利点がある。
[10] In this tire 1, in the tire 1 described in [9] above, the carcass cord is formed by twisting a plurality of strands, and the strand diameter φcss [mm] of the carcass cord is the same as that of the carcass cord. It is in the range of 0.30≦φcss/φcs≦0.90 with respect to the cord diameter φcs [mm] of the cord. This has the advantage of realizing the strong Tcs of the carcass layer 13 described above.
また、[11]このタイヤ1では、上記[8]に記載のタイヤ1において、カーカス層13が、一対のカーカスプライ13A、13Bを積層して成る(図9参照)。また、一対のカーカスプライ13A、13Bが、有機繊維材から成るカーカスコード13ccをコートゴム13crで被覆して構成される。また、カーカスコード13ccのコード径φcs[mm](図中の寸法記号省略)が、0.60≦φcs≦0.90の範囲にある。また、カーカスコード13ccの打ち込み本数Ecs[本/50mm]が、40≦Ecs≦70の範囲にある。これにより、上記したカーカス層13の強力Tcsが実現される利点がある。
[11] In this tire 1, in the tire 1 described in [8] above, the carcass layer 13 is formed by laminating a pair of carcass plies 13A and 13B (see FIG. 9). Further, a pair of carcass plies 13A and 13B are constructed by covering a carcass cord 13cc made of an organic fiber material with a coat rubber 13cr. Further, the cord diameter φcs [mm] (dimension symbol in the figure is omitted) of the carcass cord 13cc is in the range of 0.60≦φcs≦0.90. Further, the driving number Ecs [pieces/50 mm] of the carcass cord 13cc is in the range of 40≦Ecs≦70. This has the advantage of realizing the strong Tcs of the carcass layer 13 described above.
また、[12]このタイヤ1では、上記[1]~[11]のいずれか一つに記載のタイヤ1において、サイドプロファイル上の点Auにおけるタイヤサイド部のトータルゲージGu[mm]が、タイヤ外径OD[mm]に対して0.010≦Gu/OD≦0.080の範囲にある。これにより、タイヤサイド部の径方向外側領域のトータルゲージGuが適正化される利点がある。具体的に、上記下限により、タイヤサイド部の径方向外側領域のトータルゲージGuが確保され、高負荷での使用時におけるタイヤ変形が抑制されて、タイヤの耐久性能が確保される。特に小径タイヤでは、高内圧および高負荷での使用を想定されるため、上記したタイヤの耐久性能が顕著に得られる。上記上限により、トータルゲージGuが過大となることに起因するタイヤの転がり抵抗の悪化が抑制される。
[12] In this tire 1, in the tire 1 described in any one of [1] to [11] above, the total gauge Gu [mm] of the tire side portion at the point Au on the side profile is The outer diameter OD [mm] is in the range of 0.010≦Gu/OD≦0.080. This has the advantage of optimizing the total gauge Gu in the radially outer region of the tire side portion. Specifically, the above lower limit ensures the total gauge Gu of the radially outer region of the tire side portion, suppresses tire deformation during use under high load, and ensures tire durability. In particular, small-diameter tires are expected to be used under high internal pressure and high loads, so the above-mentioned tire durability performance can be significantly achieved. The above upper limit suppresses deterioration of the rolling resistance of the tire due to the total gauge Gu becoming excessively large.
図13~図15は、この発明の実施の形態にかかるタイヤの性能試験の結果を示す図表である。
FIGS. 13 to 15 are charts showing the results of performance tests on tires according to embodiments of the present invention.
この性能試験では、複数種類の試験タイヤについて、(1)耐久性能および(2)低転がり抵抗性能(燃費消費率)に関する評価が行われた。また、小径タイヤの一例として、2種類のタイヤサイズの試験タイヤが用いられる。具体的に、[A]タイヤサイズ145/80R12の試験タイヤがリムサイズ12×4.00Bのリムに組付けられ、また、[B]タイヤサイズ235/45R10の試験タイヤがリムサイズ10のリムに組付けられる。
In this performance test, multiple types of test tires were evaluated regarding (1) durability performance and (2) low rolling resistance performance (fuel consumption rate). Further, as an example of a small diameter tire, test tires of two types of tire sizes are used. Specifically, [A] a test tire with a tire size of 145/80R12 was assembled on a rim with a rim size of 12 x 4.00B, and [B] a test tire with a tire size of 235/45R10 was assembled on a rim with a rim size of 10. It will be done.
(1)耐久性能に関する評価では、ドラム径1707[mm]の室内ドラム試験機が使用され、試験タイヤにJATMAの規定内圧の80[%]の内圧およびJATMAの規定荷重の88[%]の荷重が付与される。そして、走行速度81[km/h]にて2時間毎に13[%]ずつ荷重を増加させて、タイヤが故障するまでの走行距離が測定される。そして、この測定結果に基づいて比較例を基準(100)とした指数評価が行われる。この評価は、数値が大きいほど好ましい。
(1) In the evaluation of durability performance, an indoor drum testing machine with a drum diameter of 1707 mm was used, and the test tire was loaded with an internal pressure of 80% of the JATMA specified internal pressure and 88% of the JATMA specified load. will be granted. Then, at a running speed of 81 [km/h], the load was increased by 13 [%] every two hours, and the distance traveled until the tire failed was measured. Then, based on this measurement result, an index evaluation is performed using the comparative example as a standard (100). In this evaluation, the larger the numerical value, the better.
(2)低転がり抵抗性能に関する評価では、試験タイヤにJATMAの規定内圧の80[%]の内圧およびJATMAの規定荷重の80[%]の荷重が付与される。また、試験タイヤを総輪に装着した4輪の低床車両が、全長2[km]のテストコースを速度100[km/h]で50周走行する。その後に、燃費消費率[km/l]が算出されて評価が行われる。この評価は、比較例を基準(100)とした指数評価により行われ、数値が大きいほど燃費消費率が小さく、転がり抵抗が減少する傾向にあり好ましい。また、評価が98以上であれば、低転がり抵抗性能が適正に確保されているといえる。
(2) In the evaluation regarding low rolling resistance performance, an internal pressure of 80 [%] of the JATMA specified internal pressure and a load of 80 [%] of the JATMA specified load are applied to the test tire. Furthermore, a four-wheeled low-floor vehicle with test tires mounted on all wheels runs 50 laps on a test course with a total length of 2 [km] at a speed of 100 [km/h]. After that, the fuel consumption rate [km/l] is calculated and evaluated. This evaluation is performed by index evaluation using the comparative example as a standard (100), and the larger the value, the lower the fuel consumption rate and the lower the rolling resistance, which is preferable. Moreover, if the evaluation is 98 or more, it can be said that low rolling resistance performance is appropriately ensured.
実施例の試験タイヤ1~29は、特に図1~図3および図8に記載した構造を備え、一対のビードコア11、11と、単層のカーカスプライから成るカーカス層13と、一対の交差ベルト141、142、ベルトカバー143および一対のベルトエッジカバー144、144から成るベルト層14と、トレッドゴム15、サイドウォールゴム16およびリムクッションゴム17とを備える。また、実施例1の試験タイヤでは、タイヤ外径ODが531[mm]であり、タイヤ総幅SWおよびタイヤ断面幅DWが143[mm]であり、タイヤ断面高さSHが123[mm]であり、タイヤ内径が305[mm]である。また、インナーライナ18がブチルゴムを主成分とするゴム組成物あるいは熱可塑性樹脂から成る。
The test tires 1 to 29 of the examples were particularly equipped with the structures shown in FIGS. 1 to 3 and 8, and included a pair of bead cores 11, 11, a carcass layer 13 consisting of a single carcass ply, and a pair of crossed belts. 141, 142, a belt layer 14 consisting of a belt cover 143 and a pair of belt edge covers 144, 144, tread rubber 15, sidewall rubber 16 and rim cushion rubber 17. Further, in the test tire of Example 1, the tire outer diameter OD was 531 [mm], the tire total width SW and the tire cross-sectional width DW were 143 [mm], and the tire cross-sectional height SH was 123 [mm]. The inner diameter of the tire is 305 [mm]. Further, the inner liner 18 is made of a rubber composition containing butyl rubber as a main component or a thermoplastic resin.
比較例の試験タイヤは、実施例1の試験タイヤにおいて、点Iuから点Icまでの領域におけるカーカスプライの最内層13Aのカーカスコード13ccの中心からタイヤ内面までの距離TLu[mm](図12参照)が小さく設定されている。
The test tire of the comparative example was the same as the test tire of Example 1, but the distance TLu [mm] from the center of the carcass cord 13cc of the innermost layer 13A of the carcass ply to the inner surface of the tire in the region from point Iu to point Ic (see FIG. 12) ) is set small.
試験結果が示すように、実施例の試験タイヤでは、タイヤの耐久性能および低転がり抵抗性能が両立することが分かる。
As shown by the test results, it can be seen that the test tires of Examples achieve both tire durability performance and low rolling resistance performance.
1 タイヤ;10 リム;11 ビードコア;12 ビードフィラー;13 カーカス層;131 本体部;132 巻き上げ部;14 ベルト層;141、142 交差ベルト;143 ベルトカバー;144 ベルトエッジカバー;15 トレッドゴム;151 キャップトレッド;152 アンダートレッド;16 サイドウォールゴム;17 リムクッションゴム;18 インナーライナ;21~23 周方向主溝
1 Tire; 10 Rim; 11 Bead core; 12 Bead filler; 13 Carcass layer; 131 Main body; 132 Winding portion; 14 Belt layer; 141, 142 Cross belt; 143 Belt cover; 144 Belt edge cover; 15 Tread rubber; Tread; 152 Undertread; 16 Sidewall rubber; 17 Rim cushion rubber; 18 Inner liner; 21-23 Circumferential main groove
Claims (12)
- 一対のビードコアと、前記ビードコアに架け渡されたカーカス層と、前記カーカス層の径方向外側に配置されたベルト層と、カーカス層の内面に配置されたインナーライナとを備え、
タイヤ外径OD[mm]が、200≦OD≦660の範囲にあり、
タイヤ総幅SW[mm]が、100≦SW≦400の範囲にあり、
タイヤ子午線方向の断面視にて、前記ベルト層の最内層の端部に対してタイヤ径方向の同位置にあるサイドプロファイル上の点Auを定義し、点Auから前記カーカス層に下した垂線の足を点Iuとして定義し、タイヤ最大幅位置Acから前記カーカス層に下した垂線の足を点Icとして定義し、
前記カーカス層が、カーカスコードをコートゴムで被覆して成る単一層あるいは複数層のカーカスプライから構成され、且つ、
点Iuから点Icまでの領域における前記カーカスプライの最内層の前記カーカスコードの中心からタイヤ内面までの距離TLu[mm]が、タイヤ外径OD[mm]に対して0.00010≦TLu/OD≦0.01500の範囲にあることを特徴とするタイヤ。 comprising a pair of bead cores, a carcass layer spanning the bead cores, a belt layer disposed on the radially outer side of the carcass layer, and an inner liner disposed on the inner surface of the carcass layer,
The tire outer diameter OD [mm] is in the range of 200≦OD≦660,
The total tire width SW [mm] is in the range of 100≦SW≦400,
In a cross-sectional view in the tire meridian direction, a point Au on the side profile at the same position in the tire radial direction with respect to the end of the innermost layer of the belt layer is defined, and a perpendicular line drawn from the point Au to the carcass layer is defined. The foot is defined as a point Iu, the foot of a perpendicular line drawn from the tire maximum width position Ac to the carcass layer is defined as a point Ic,
The carcass layer is composed of a single layer or a plurality of carcass plies formed by covering a carcass cord with a coated rubber, and
The distance TLu [mm] from the center of the carcass cord of the innermost layer of the carcass ply to the inner surface of the tire in the region from point Iu to point Ic is 0.00010≦TLu/OD with respect to the tire outer diameter OD [mm]. A tire characterized in that it is in the range of ≦0.01500. - 点Iuから点Icまでの前記領域における距離TLu[mm]の最小値TLu_minおよび最大値TLu_maxが、0.30≦TLu_min/TLu_max≦1.00の関係を有する請求項1に記載のタイヤ。 The tire according to claim 1, wherein a minimum value TLu_min and a maximum value TLu_max of the distance TLu [mm] in the region from point Iu to point Ic have a relationship of 0.30≦TLu_min/TLu_max≦1.00.
- 点Iuから点Icまでの前記領域における距離TLu[mm]が、0.1≦TLu≦4.0の範囲にある請求項1に記載のタイヤ。 The tire according to claim 1, wherein a distance TLu [mm] in the region from point Iu to point Ic is in a range of 0.1≦TLu≦4.0.
- 点Iuから点Icまでの前記領域におけるタイヤサイド部のトータルゲージGa[mm]の最小値Ga_minと、同位置における上記距離TLuに相当する距離TLu’[mm]とが、0.05≦TLu’/Ga_minの関係を有する請求項1に記載のタイヤ。 The minimum value Ga_min of the total gauge Ga [mm] of the tire side portion in the area from point Iu to point Ic and the distance TLu' [mm] corresponding to the distance TLu at the same position are 0.05≦TLu' The tire according to claim 1, having a relationship of /Ga_min.
- 点Iuから点Icまでの前記領域における距離TLu[mm]が、前記インナーライナの酸素透過係数α[mm・cc/(m^2・day・mmHg)]に対して0.005≦(α^(1/2))/TLu≦1.800の関係を有する請求項1に記載のタイヤ。 The distance TLu [mm] in the region from point Iu to point Ic is 0.005≦(α^ The tire according to claim 1, having a relationship of (1/2))/TLu≦1.800.
- 点Iuから点Icまでの前記領域における前記インナーライナのスプライス量Is[mm]が、タイヤ外径OD[mm]に対して0.01≦Is/OD≦0.10の範囲にある請求項1に記載のタイヤ。 Claim 1: The splice amount Is [mm] of the inner liner in the region from point Iu to point Ic is in a range of 0.01≦Is/OD≦0.10 with respect to tire outer diameter OD [mm]. Tires listed in.
- 左右のタイヤ接地端から前記カーカス層に下した垂線の足のそれぞれを点B2、B2として定義し、且つ、
点Iuから点Icまでの前記領域における距離TLu[mm]の最小値TLu_minが、点B2、B2の間の領域における前記カーカスプライの最内層の前記カーカスコードの中心からタイヤ内面までの距離TL[mm]の最小値TL_minに対して1.00≦TLu_min/TL_minの範囲にある請求項1に記載のタイヤ。 The legs of the perpendicular line drawn from the left and right tire ground contact ends to the carcass layer are defined as points B2 and B2, and,
The minimum value TLu_min of the distance TLu [mm] in the region from point Iu to point Ic is the distance TL[ from the center of the carcass cord of the innermost layer of the carcass ply to the inner surface of the tire in the region between points B2 and B2. The tire according to claim 1, wherein the minimum value TL_min of [mm] is in the range of 1.00≦TLu_min/TL_min. - 前記カーカス層を構成するカーカスプライの幅50[mm]あたりの強力Tcs[N/50mm]が、タイヤ外径OD[mm]に対して17≦Tcs/OD≦120の範囲にある請求項1に記載のタイヤ。 According to claim 1, the strength Tcs [N/50mm] per width 50 [mm] of the carcass ply constituting the carcass layer is in the range of 17≦Tcs/OD≦120 with respect to the tire outer diameter OD [mm]. Tires listed.
- 前記カーカス層のカーカスプライが、スチールから成るカーカスコードをコートゴムで被覆して構成され、
前記カーカスコードのコード径φcs[mm]が、0.15≦φcs≦1.10の範囲にあり、且つ、
前記カーカスコードの打ち込み本数Ecs[本/50mm]が、25≦Ecs≦80の範囲にある請求項8に記載のタイヤ。 The carcass ply of the carcass layer is constructed by covering a carcass cord made of steel with a coated rubber,
The cord diameter φcs [mm] of the carcass cord is in the range of 0.15≦φcs≦1.10, and
The tire according to claim 8, wherein the number of carcass cords (Ecs/50 mm) is in the range of 25≦Ecs≦80. - 前記カーカスコードが、複数の素線を撚り合わせて成り、且つ、前記カーカスコードの素線径φcss[mm]が、前記カーカスコードのコード径φcs[mm]に対して0.30≦φcss/φcs≦0.90の範囲にある請求項9に記載のタイヤ。 The carcass cord is formed by twisting a plurality of wires, and the wire diameter φcss [mm] of the carcass cord is 0.30≦φcss/φcs with respect to the cord diameter φcs [mm] of the carcass cord. The tire according to claim 9, which is in the range ≦0.90.
- 前記カーカス層が、一対のカーカスプライを積層して成り、
前記一対のカーカスプライが、有機繊維材から成るカーカスコードをコートゴムで被覆して構成され、
前記カーカスコードのコード径φcs[mm]が、0.60≦φcs≦0.90の範囲にあり、且つ、
前記カーカスコードの打ち込み本数Ecs[本/50mm]が、40≦Ecs≦70の範囲にある請求項8に記載のタイヤ。 The carcass layer is formed by laminating a pair of carcass plies,
The pair of carcass plies are constructed by covering a carcass cord made of organic fiber material with a coated rubber,
The cord diameter φcs [mm] of the carcass cord is in the range of 0.60≦φcs≦0.90, and
The tire according to claim 8, wherein the number of carcass cords (Ecs/50 mm) is in the range of 40≦Ecs≦70. - 前記サイドプロファイル上の点Auにおけるタイヤサイド部のトータルゲージGu[mm]が、タイヤ外径OD[mm]に対して0.010≦Gu/OD≦0.080の範囲にある請求項1に記載のタイヤ。 According to claim 1, the total gauge Gu [mm] of the tire side portion at the point Au on the side profile is in the range of 0.010≦Gu/OD≦0.080 with respect to the tire outer diameter OD [mm]. tires.
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Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH07186608A (en) * | 1993-12-28 | 1995-07-25 | Sumitomo Rubber Ind Ltd | Steel radial tire for passenger car |
JP2012051537A (en) * | 2010-09-03 | 2012-03-15 | Sumitomo Rubber Ind Ltd | Pneumatic tire and method of manufacturing the same |
JP2014213838A (en) * | 2013-04-30 | 2014-11-17 | 株式会社ブリヂストン | Pneumatic radial tire for passenger car |
JP2019119422A (en) * | 2018-01-11 | 2019-07-22 | 横浜ゴム株式会社 | Pneumatic tire |
JP2022019516A (en) * | 2020-07-16 | 2022-01-27 | 横浜ゴム株式会社 | Tire, method for producing tire and vehicle |
-
2022
- 2022-08-22 JP JP2022132026A patent/JP2024029653A/en active Pending
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Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH07186608A (en) * | 1993-12-28 | 1995-07-25 | Sumitomo Rubber Ind Ltd | Steel radial tire for passenger car |
JP2012051537A (en) * | 2010-09-03 | 2012-03-15 | Sumitomo Rubber Ind Ltd | Pneumatic tire and method of manufacturing the same |
JP2014213838A (en) * | 2013-04-30 | 2014-11-17 | 株式会社ブリヂストン | Pneumatic radial tire for passenger car |
JP2019119422A (en) * | 2018-01-11 | 2019-07-22 | 横浜ゴム株式会社 | Pneumatic tire |
JP2022019516A (en) * | 2020-07-16 | 2022-01-27 | 横浜ゴム株式会社 | Tire, method for producing tire and vehicle |
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