WO2011046195A1 - 空気入りタイヤ - Google Patents
空気入りタイヤ Download PDFInfo
- Publication number
- WO2011046195A1 WO2011046195A1 PCT/JP2010/068120 JP2010068120W WO2011046195A1 WO 2011046195 A1 WO2011046195 A1 WO 2011046195A1 JP 2010068120 W JP2010068120 W JP 2010068120W WO 2011046195 A1 WO2011046195 A1 WO 2011046195A1
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- WIPO (PCT)
- Prior art keywords
- tire
- steel cord
- cord
- steel
- layer
- Prior art date
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Classifications
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- D—TEXTILES; PAPER
- D07—ROPES; CABLES OTHER THAN ELECTRIC
- D07B—ROPES OR CABLES IN GENERAL
- D07B1/00—Constructional features of ropes or cables
- D07B1/06—Ropes or cables built-up from metal wires, e.g. of section wires around a hemp core
- D07B1/0606—Reinforcing cords for rubber or plastic articles
- D07B1/062—Reinforcing cords for rubber or plastic articles the reinforcing cords being characterised by the strand configuration
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- 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
- B60C9/0007—Reinforcements made of metallic elements, e.g. cords, yarns, filaments or fibres made from metal
-
- 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
- B60C9/18—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers
- B60C9/20—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers built-up from rubberised plies each having all cords arranged substantially parallel
-
- D—TEXTILES; PAPER
- D07—ROPES; CABLES OTHER THAN ELECTRIC
- D07B—ROPES OR CABLES IN GENERAL
- D07B1/00—Constructional features of ropes or cables
- D07B1/06—Ropes or cables built-up from metal wires, e.g. of section wires around a hemp core
- D07B1/0606—Reinforcing cords for rubber or plastic articles
- D07B1/0666—Reinforcing cords for rubber or plastic articles the wires being characterised by an anti-corrosive or adhesion promoting coating
-
- 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
- B60C9/0007—Reinforcements made of metallic elements, e.g. cords, yarns, filaments or fibres made from metal
- B60C2009/0021—Coating rubbers for steel cords
-
- 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
- B60C9/18—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers
- B60C9/20—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers built-up from rubberised plies each having all cords arranged substantially parallel
- B60C2009/2074—Physical properties or dimension of the belt cord
- B60C2009/2077—Diameters of the cords; Linear density thereof
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- D—TEXTILES; PAPER
- D07—ROPES; CABLES OTHER THAN ELECTRIC
- D07B—ROPES OR CABLES IN GENERAL
- D07B2201/00—Ropes or cables
- D07B2201/20—Rope or cable components
- D07B2201/2001—Wires or filaments
- D07B2201/2006—Wires or filaments characterised by a value or range of the dimension given
-
- D—TEXTILES; PAPER
- D07—ROPES; CABLES OTHER THAN ELECTRIC
- D07B—ROPES OR CABLES IN GENERAL
- D07B2201/00—Ropes or cables
- D07B2201/20—Rope or cable components
- D07B2201/2001—Wires or filaments
- D07B2201/201—Wires or filaments characterised by a coating
- D07B2201/2011—Wires or filaments characterised by a coating comprising metals
-
- D—TEXTILES; PAPER
- D07—ROPES; CABLES OTHER THAN ELECTRIC
- D07B—ROPES OR CABLES IN GENERAL
- D07B2201/00—Ropes or cables
- D07B2201/20—Rope or cable components
- D07B2201/2015—Strands
- D07B2201/2024—Strands twisted
- D07B2201/2025—Strands twisted characterised by a value or range of the pitch parameter given
-
- D—TEXTILES; PAPER
- D07—ROPES; CABLES OTHER THAN ELECTRIC
- D07B—ROPES OR CABLES IN GENERAL
- D07B2201/00—Ropes or cables
- D07B2201/20—Rope or cable components
- D07B2201/2015—Strands
- D07B2201/2041—Strands characterised by the materials used
-
- D—TEXTILES; PAPER
- D07—ROPES; CABLES OTHER THAN ELECTRIC
- D07B—ROPES OR CABLES IN GENERAL
- D07B2205/00—Rope or cable materials
- D07B2205/30—Inorganic materials
- D07B2205/3021—Metals
- D07B2205/3025—Steel
- D07B2205/3046—Steel characterised by the carbon content
- D07B2205/3053—Steel characterised by the carbon content having a medium carbon content, e.g. greater than 0,5 percent and lower than 0.8 percent respectively HT wires
-
- D—TEXTILES; PAPER
- D07—ROPES; CABLES OTHER THAN ELECTRIC
- D07B—ROPES OR CABLES IN GENERAL
- D07B2205/00—Rope or cable materials
- D07B2205/30—Inorganic materials
- D07B2205/3021—Metals
- D07B2205/3085—Alloys, i.e. non ferrous
- D07B2205/3089—Brass, i.e. copper (Cu) and zinc (Zn) alloys
Definitions
- the present invention relates to a pneumatic tire, and more particularly, a pneumatic tire that improves productivity while maintaining fatigue resistance of a steel cord used for a reinforcing layer, and further improves tire durability performance.
- the present invention relates to a pneumatic radial tire that can be used.
- a steel cord used for a belt layer of a pneumatic tire uses a high carbon steel having a carbon content exceeding 0.75% in order to obtain high strength (such as 2900 MPa or more).
- What is set to * 2 * 0.30HT twist structure is used (for example, refer patent documents 1, 2, and 3).
- the carbon content is 0.82% by weight in order to maintain the belt folding of the belt layer using the steel cord having a 1 ⁇ 2 ⁇ 0.30HT twisted structure and the separation durability of the belt layer.
- a pneumatic radial tire is disclosed in which a cord angle is 23 ° and a cord end is 47.25 (pieces / 50 mm).
- Patent Document 4 when the reinforcing layer is formed by a steel cord having a 1 ⁇ 2 structure in which two strands that have been spirally shaped in advance are twisted,
- the length p 1 is equal to or greater than the phase length p 2 of the spiral of the elemental wire (p 2 ⁇ p 1 ), the phase height d 1 of the twist is greater than the phase height d 2 of the spiral of the elemental wire, and
- the wire diameter is set to 3 times or less of the wire diameter D (d 2 ⁇ d 1 ⁇ 3D)
- the penetration resistance of the steel cord coating rubber is improved and the fretting phenomenon is reduced. And compression fatigue resistance can be obtained.
- Patent Document 5 relating to the application of the present applicant, a steel cord of 1 ⁇ 2 is used as the steel cord of the outermost belt layer, and the tie rate of the steel cord strand is 105% or more.
- the pitch 20 times or less of the wire diameter d and making the breaking elongation of the cord taken out of the tire 4% or more both weight reduction and rust resistance and impact resistance are made even better. You can do that.
- Japanese Patent Laid-Open No. 62-234922 Japanese Unexamined Patent Publication No. Hei 3-193983 JP 2000-178887
- the steel having a high carbon content used in Patent Documents 1 to 3 is hard and has a drawback that the intermediate wire drawing productivity is not good because the degree of work cannot be increased when the wire is drawn.
- a method of using a steel rod having a soft low carbon content which is easy to increase the degree of wire drawing, as a material, and performing strong working with a high degree of intermediate wire drawing. By doing so, the orientation of the steel structure is increased, so that the strength of the steel cord can be made the same level as when steel with a high carbon content is used.
- the steel material is soft, so that the wire strands in the 1 ⁇ 2 twisted steel cord are in point contact during use, so that the steel There was a problem that the fatigue resistance of the cord was lowered.
- Patent Document 4 the twisting phase length and height of the steel cord having a 1 ⁇ 2 structure, the phase length and height of the helix of the strand, and the strand diameter are set in the above relationship, so that The gap between the wires is appropriately increased, the permeability of the coated rubber is improved to reduce the fretting phenomenon, and the bending fatigue resistance and compression fatigue resistance of the steel cord are not lowered. There is a problem that it cannot be said that the fatigue resistance is sufficiently improved because the twist angle and the forming ratio of the steel cord are not properly defined. Moreover, in patent document 5, by making the molding rate and twist pitch etc.
- the periphery of the wire is substantially completely covered with rubber, and simultaneously with weight reduction, although it has good rust resistance and impact resistance, the steel cord twist angle is not properly defined, and the rate of forming is not sufficient, so the fatigue resistance is sufficiently improved. There was a problem that it could not be said.
- Patent Document 6 states that a long pitch steel cord can be obtained by defining the twist pitch within a predetermined range.
- the twist angle is set to the conventional value of 3.8. Only the ones with the angle of 3.85 ° have been disclosed, it has not been disclosed that the twist angle is reduced and the twist length is increased, the molding rate is not properly defined, There was a problem that it could not be said that the improvement in fatigue was sufficient.
- the steel cords are made longer and the strands are changed from "point contact" to "line contact”.
- An object of the present invention is to provide a pneumatic tire capable of improving the productivity while solving the problems of the prior art and maintaining the fatigue resistance of a steel cord used for a reinforcing layer. .
- the other object of the present invention is to appropriately define the average value of the twist angle and the shaping ratio and the standard deviation ⁇ of the steel cord having a 1 ⁇ 2 structure used for the pneumatic radial tire.
- An object of the present invention is to provide a pneumatic radial tire capable of improving the fatigue resistance of a steel cord and, as a result, improving the durability of the tire.
- a pneumatic tire according to the present invention is a pneumatic tire using a steel cord having a 1 ⁇ 2 structure in which two wire strands are twisted together as a reinforcing layer.
- the carbon content is 0.60 to 0.75%
- the strength of the steel cord in the tire is 2900 to 3500 MPa
- the twist angle of the steel cord is 1.5 to 3.0. It is characterized by °.
- the thickness of the brass plating layer formed on the outer surface of the wire element of the steel cord is preferably 0.25 to 0.32 ⁇ m.
- the diameter of the wire element of the steel cord is preferably 0.28 to 0.35 mm.
- the twist length of the steel cord is preferably 18 to 40 mm.
- the reinforcing layer is preferably a belt layer and / or a side reinforcing layer.
- the steel cord has a die forming rate of 95 to 105% as an average value and 5 to 20% as a standard deviation ⁇ . Moreover, it is preferable that at least one of the two wire strands of the steel cord is finely brazed. Moreover, it is preferable that the pneumatic tire is a pneumatic radial tire.
- the steel cord in a pneumatic tire using a 1 ⁇ 2 twisted structure steel cord as a reinforcing layer, the steel cord has a carbon content of 0.60 to 0.75% and is flexible, Since the degree of processing at the time of processing can be increased, productivity can be improved, and strong processing for high orientation is possible, so that the conventional high carbon content of 2900 to 3500 MPa is achieved.
- the amount of steel cord can be equal to that of the steel cord, and the twist angle is 1.5 to 3.0 ° so that the wire strands in the steel cord can be brought close to line contact instead of point contact. Therefore, it is possible to prevent point contact breakage between the wire strands and to improve the fatigue resistance of the steel cord.
- the present invention provides, for example, fatigue resistance of a steel cord of a pneumatic tire with respect to the pneumatic tire of Patent Document 1 that uses a steel cord that has not been subjected to strong processing and low twisting of a wire having a low carbon content. Excellent effect on productivity and productivity.
- the steel cord is made to have a low twist angle to make the wires contact each other, and the standard deviation ⁇ of the molding rate is increased to create a local gap that can penetrate the rubber.
- the strands with low twist angle are prevented from moving apart and rubbing, and the moldability (average value) is limited to around 100%, resulting in instability of the cord shape.
- the elastic modulus can be prevented from lowering, and as a result, tire durability can be improved.
- FIG. 1 is a cross-sectional view showing a right half cross-sectional shape with respect to the meridian CL of one embodiment of the pneumatic tire of the present invention.
- a pneumatic tire (hereinafter simply referred to as a tire) 10 shown in FIG. 1 is a pneumatic radial tire, and mainly includes a tread portion 12, a shoulder portion 14, a sidewall portion 16, and a bead portion 18. Have as part.
- the tire left half not shown in FIG. 1 has the same configuration.
- the tire width direction refers to a direction parallel to the tire rotation axis indicated by an arrow a in FIG. 1
- the tire radial direction refers to a rotation axis indicated by an arrow b in FIG.
- the direction orthogonal to Further, the tire circumferential direction refers to the direction of rotation with the rotation axis as the axis serving as the center of rotation.
- the tire inner side means the lower side of the tire in FIG. 1 in the tire radial direction, that is, the tire inner side facing the cavity region R that applies a predetermined internal pressure to the tire
- the tire outer side means the upper side of the tire in FIG. That is, it means a tire outer surface side that can be visually recognized by the user on the side opposite to the tire inner peripheral surface.
- the tire 10 includes a carcass layer 20, a belt layer 22, a belt cover layer 24, a side reinforcing layer 26, a bead core 28, a bead filler 30, a tread rubber layer 32, a side wall rubber layer 34, and a rim cushion. It mainly has a rubber layer 36 and an inner liner rubber 38 layer. As described above, the tire left half not shown in FIG. 1 has a similar configuration as a matter of course.
- a carcass layer 20 is mounted between a pair of left and right bead portions 18, 18, and both end portions in the tire width direction are outside the tire core 28 from the inner side to the outer side. Is rolled up.
- a belt layer 22 made of two steel cords is disposed so that the reinforcing cords intersect each other.
- a side reinforcing layer 26 made of a steel cord is provided along the outside of the folded end portion of the carcass layer 20 in a region extending from the sidewall portion 16 to the bead portion 18.
- the tread portion 12 is provided with a land portion 12b constituting a tread surface 12a outside the tire and a tread groove 12c formed in the tread surface 12a.
- the land portion 12b is partitioned by the tread groove 12c.
- the tread groove 12c has a main groove formed continuously in the tire circumferential direction and a plurality of lug grooves (not shown) extending in the tire width direction.
- a tread pattern is formed on the tread surface 12a by the tread groove 12c and the land portion 2b.
- the carcass layer 20 extends in the tire width direction from a portion corresponding to the tread portion 12 to a bead portion 18 through a portion corresponding to the shoulder portion 14 and the sidewall portion 16 to form a tire skeleton.
- the carcass layer 20 has a configuration in which reinforcing cords made of organic fibers are arranged in one direction at regular intervals, for example, in the tire width direction, and covered with a cord coating rubber.
- the carcass layer 20 is folded back from the tire inner side to the tire outer side by a pair of left and right bead cores 28, which will be described later.
- the carcass layer 20 forms an end A in the region of the side wall part 16, and the main body part 20a and the folded part with the bead core 28 as a boundary. 20b.
- the left half of the tire not shown in FIG. 1 also has a similar end.
- the belt layer 22 is a reinforcing layer that is affixed in the tire circumferential direction to reinforce the carcass layer 10 and is a reinforcing layer to which the present invention is applied.
- the belt layer 22 is provided in a portion corresponding to the tread portion 12 between the left and right shoulder portions 14, and includes an inner first belt 22a and an outer second belt 22b.
- both the first belt 22a and the second belt 22b of the belt layer 22 face the direction in which the reinforcing cord made of the steel cord to which the present invention is applied is inclined with respect to the tire circumferential direction at regular intervals.
- a cord coating rubber hereinafter referred to as a coating rubber
- the steel cord that is a feature of the present invention and constitutes the reinforcing cord of the first belt 22a and the second belt 22b will be described in detail later.
- the steel cord according to the present invention is applied to both the first belt 22a and the second belt 22b of the belt layer 22, but the present invention is not limited to this, and the present invention is applied to only one of the present invention.
- both of the steel belts according to the present invention are not applied, and conventionally known steel belts, polyesters, nylons may be applied.
- a conventionally known reinforcing cord made of an organic fiber cord made of aromatic polyamide or the like may be used.
- a belt cover layer 24 having organic fibers that covers the belt layer 22 from end to end in the tire width direction and reinforces the belt layer 22 is provided outside the tire of the belt layer 22.
- the belt cover layer 24 may cover only a part of the belt layer 22 as long as the belt layer 22 can be reinforced.
- the tire 10 includes a belt cover layer 24 including a layer 24 a that covers the belt layer 22 from end to end in the tire width direction and a layer 24 b that covers the end of the belt layer 22 on the outer side. It is composed of
- the bead portion 18 is provided with a bead core 28 that functions to fold the carcass layer 20 and fix the tire 10 to the wheel, and a bead filler 30 so as to contact the bead core 28. Therefore, the bead core 28 and the bead filler 30 are sandwiched between the main body portion 20a and the folded portion 20b of the carcass layer 20. Further, a side reinforcing layer 26 including a reinforcing cord that is inclined with respect to the tire circumferential direction is embedded in the bead portion 18.
- the side reinforcing layer 26 includes the bead portion 18 between the main body portion 20a of the carcass layer 20 and the bead filler 30, and the side wall portion 16 includes the main body portion 20a and the folded portion 20b of the carcass layer 20. And extends from the bead core 28 to the end B on the shoulder 14 side along the tire radial direction from the end A of the folded portion 20b.
- the other end portion C of the side reinforcing layer 26 exists in the vicinity of the bead core 28 between the main body portion 20 a of the carcass layer 20 and the bead filler 6.
- the side reinforcing layer 26 is provided between the folded portion 20b of the carcass layer 20 and the bead core 28 and / or the bead filler 30 in the bead portion 18, and between the main body portion 20a and the folded portion 20b in the sidewall portion 16.
- the bead portion 18 may be disposed outside the folded portion 20b in the tire width direction, and the sidewall portion 16 may be disposed outside the main body portion 20a. Furthermore, these may be arranged in combination.
- the side reinforcing layer 26 is configured by arranging reinforcing cords made of steel cords to which the present invention is applied in a direction inclined with respect to the tire circumferential direction at regular intervals, and covering with a cord coating rubber.
- the steel cord that is a feature of the present invention and constitutes the reinforcing cord of the side reinforcing layer 26 will be described in detail later.
- the steel cord according to the present invention is applied to the side reinforcing layer 26.
- the present invention is not particularly limited to this, and the present invention is applied to the belt layer 22 described above.
- a conventionally known reinforcing cord made of a conventionally known steel belt or an organic fiber cord made of polyester, nylon, aromatic polyamide or the like may be used.
- the side reinforcing layer 26 can reinforce the side (side surface) of the tire 10, that is, the bead portion 18 and / or the sidewall portion 16, only the whole or a part of the bead portion 18 and / or the sidewall portion 16 may be used.
- the position of the end portion is not limited.
- the end portion of the side reinforcing layer 26 may be extended to a region in contact with the belt layer 22 of the shoulder portion 14 and may be provided for all of the bead portion 18 and the sidewall portion 16, or only the bead portion 18.
- it may be provided only for the side wall part 16, or may be provided by being divided into a plurality of parts, for example, divided into a bead part 18 and a side wall part 16.
- the side reinforcement layer 26 is disposed between the bead filler 30 and the folded portion 20 b of the carcass layer 20.
- the side reinforcing layer 26 is preferably disposed so as to wrap the bead core 28 and the bead filler 30.
- the tire 10 is provided as a rubber material on a tread rubber layer 32 that constitutes the tread portion 12, a sidewall rubber layer 34 that constitutes the sidewall portion 16, a rim cushion rubber layer 36, and an inner peripheral surface of the tire.
- An inner liner rubber layer 38 is provided.
- the steel cord 40 used for the reinforcing cord of the belt layer 22 has a 1 ⁇ 2 twist structure in which two wire strands 42 are twisted at a constant pitch as shown in FIG. Become.
- the steel cord 40 has a carbon content of 0.60 to 0.75%, a strength of 2900 to 3500 MPa when embedded in the tire 10, and a twist angle ⁇ of 1.5. It is set to be -3.0 °.
- the steel cord 40 having the above configuration can be manufactured by a method as described below.
- a steel rod having a carbon content of 0.60 to 0.75% and a diameter of about 5.5 to 6.0 mm is used as a raw material.
- This steel rod with a low carbon content is first drawn to an intermediate wire having a diameter of about 2.0 ⁇ 0.02 mm. Further, this intermediate wire is subjected to brass plating, an adhesive layer with rubber, and finally. It is applied as a lubricating layer during wire drawing.
- the brass wire plated intermediate wire is subjected to a relatively high wire drawing with a final wire drawing degree of 3.8 or more to obtain a wire element having a diameter of about 0.28 to 0.35 mm. To do. Further, two of these wire elements are aligned and twisted so that the twist angle is relatively small 1.5 to 3.0 °, and the strength in the tire is 1 ⁇ 2 with 2900 to 3500 MPa.
- a steel cord having a twisted structure can be obtained.
- the wire drawing process uses a steel rod with a low carbon content, high productivity and high process can be performed.
- a high-strength wire element with a strength of 2900 MPa or more is used, and a steel cord having a 1 ⁇ 2 twist structure has a strength of 2900- It can be 3500 MPa.
- a thick intermediate wire can be drawn and formed into a wire element without deceleration, it is possible to increase the processing efficiency (weight per unit time) by thickening the intermediate wire and the plated wire. it can.
- the carbon content of the steel cord 40 is less than 0.60%, the steel cord 40 becomes too flexible and the fatigue resistance deteriorates. If the carbon content is greater than 0.75%, the steel cord 40 becomes hard, so low-speed machining is required and productivity is lowered. That is, unlike the case of the present invention described above, if the intermediate wire is not made thin, it takes a long time for the final wire drawing, and the intermediate wire drawing efficiency and the plating work efficiency are also reduced in order to make the intermediate wire thin. It will decline.
- the steel cord 40 of the present invention has a strength of 2900 to 3500 MPa when embedded in a tire so that the same level of strength as a conventional cord is maintained.
- the strength is less than 2900 MPa, the tire durability is lowered due to the strength reduction of the tire reinforcing layer.
- the strength is greater than 3500 MPa, the wire is easily broken due to a decrease in the toughness of the wire, and the tire durability is reduced.
- the steel cord 40 of the present invention has a low carbon content and is flexible, the wire strands 42 come into contact with each other during use, and there is a problem that breakage tends to occur starting from the contact point.
- the twist angle ⁇ is set to a small range of 1.5 to 3.0 °, when the wire strands 42 are in contact with each other, the wire strand is closer to the line contact than the point contact. It is possible to prevent the point contact breakage between 42.
- the twist angle ⁇ of the steel cord 40 in the tire is smaller than 1.5 °, the convergence is lowered and the cord shape becomes unstable, so that the tire durability is deteriorated.
- the twist angle ⁇ is larger than 3.0 °, the wire strands 42 easily come into point contact with each other, and the point contact breakage easily occurs.
- the value obtained from the length L by the formula ⁇ 180 / ⁇ ⁇ tan ⁇ 1 [ ⁇ ⁇ R / L).
- the wire strand 42 of the steel cord 40 has a diameter of 0.28 to 0.35 mm. If the diameter of the wire 42 is smaller than 0.28 mm, productivity cannot be improved. On the contrary, if the diameter of the wire 42 is larger than 0.35 mm, the fatigue resistance of the wire cannot be maintained.
- the brass plating layer 44 formed on the outer surface of the wire element 42 of the steel cord 40 preferably has a thickness of 0.25 to 0.32 ⁇ m. If the thickness of the brass plating layer 44 is smaller than 0.25 ⁇ m, the iron ground of the wire strand 42 is likely to be locally exposed and tire durability is deteriorated. On the other hand, if the thickness of the brass plating layer 44 is larger than 0.32 ⁇ m, the adhesive layer of the brass plating layer 44 becomes brittle, and separation from rubber tends to occur, resulting in deterioration of tire durability.
- the twist length L of the steel cord 40 is more preferably 18 to 40 mm.
- the twist length L is smaller than 18 mm, it becomes impossible to prevent the point contact breakage between the wire strands 42.
- the twist length L is larger than 40 mm, the cord shape becomes unstable due to the decrease in convergence.
- the steel cord 40 having the above-described configuration can be used not only for the belt layer 22 but also for other tire reinforcing layers such as the side reinforcing layer 26.
- the pneumatic tire according to the first embodiment of the present invention is basically configured as described above.
- the pneumatic tire according to the second embodiment of the present invention is the same as the pneumatic tire according to the first embodiment, further by appropriately defining the average value of the twist angle and the shaping ratio of the steel cord and the standard deviation ⁇ .
- the fatigue resistance of the steel cord can be further improved while maintaining the improvement in the productivity of the steel cord in, and as a result, the durability performance of the tire can be improved.
- the structure of the pneumatic tire of Embodiment 2 of the present invention has the same structure except for the steel cord twist angle, the average value of the shaping ratio, and the standard deviation ⁇ , description of the same structure Are omitted, and different points will be mainly described.
- the most characteristic steel belt of the present invention used for the first belt 22a and the second belt 22b of the belt layer 22 and the side reinforcing layer 26 will be described.
- a steel cord having a 1 ⁇ 2 structure in which two wire strands (hereinafter also simply referred to as strands) are twisted is used for a tire reinforcing layer, and the carbon content of the steel cord
- the strength of the steel cord when embedded in the tire is 2900 to 3500 MPa
- the twist angle (twist angle ⁇ ) of the steel cord in the tire is 1.
- the steel cord has a molding rate of 5 to 3.0 degrees, an average value of 95 to 105%, and a standard deviation ⁇ of 5 to 20%.
- twist angle The description of the carbon content of the steel cord, the strength of the steel cord embedded in the tire, and the twist angle ⁇ of the steel cord in the tire (hereinafter also simply referred to as the twist angle) is the same as in the first embodiment. Therefore, detailed description thereof is omitted.
- the tying rate of a single-stranded 1 ⁇ 2 steel cord in which two strands are twisted together in a tire is the cord of the steel cord when the two strands are twisted concentrically without a gap.
- the steel cord 50 is obtained by twisting the two wire strands 52 without gaps, when the two wire strands 52 that are twisted together are individually taken out, as shown in FIG. Although it is in a spirally shaped state, it expands and contracts from the twisted state, so the spiral outer diameter H1, which is the outer diameter of the spiral envelope, becomes a predetermined value.
- the steel cord shaping rate can be obtained by calculating the formula (H1 / D1) ⁇ 100.
- the calculation of the steel cord molding rate can be calculated as follows, for example. 1) First, remove the steel cord from the tire. 2) Remove the rubber outside the steel cord with a cutter knife. 3) Immerse the steel cord in acetone and heat (until the cord comes out easily). 4) While taking care not to plastically deform the strands, separate the steel cords and take out the individual strands. 5) For one strand, measure the continuous 4 strand wave height (mm) with a projector at the part located at the tire center.
- AVG average value
- ⁇ of the molding rate can be calculated as follows, for example. 1) First, remove the steel cord from the tire. 2) Remove the rubber outside the steel cord with a cutter knife. 3) Immerse the steel cord in acetone and heat (until the cord comes out easily). 4) While taking care not to plastically deform the strands, separate the steel cords and take out the individual strands. 5) For one strand, measure the continuous 4 strand wave height (mm) with a projector at
- the average value of four continuous wire wave heights is set to H1, and using the cord outer diameter D1 obtained in advance from the wire diameter, from the above formula (H1 / D1) ⁇ 100, the molding rate (%) is obtained. calculate. 7) For the other strand, determine the molding rate in the same way. 8) The same test is carried out at 8 places on the circumference of the tire. 9) Obtain the molding rate of 8 steel cords (and therefore 16 strands) and calculate the steel cord molding rate (AVG, ⁇ ). In this way, the average value (AVG) of the molding rate and the standard deviation ⁇ can be calculated.
- the twist angle ⁇ of the steel cord having the conventional 1 ⁇ 2 structure is, for example, 3.9 degrees for a steel cord having a twist length of 14 mm, and is changed to 1.5 to 3.0 degrees.
- the standard deviation ⁇ of the steel cord molding rate is increased to 5 to 20% to create a local gap through which the coated rubber can penetrate. By improving the penetration of the coated rubber, the strands move apart and rub against each other.
- the twist angle of the steel cord is limited to a range of 1.5 to 3.0 degrees. The reason for this is that, as described above, if the twist angle of the steel cord is less than 1.5 degrees, the shape of the steel cord becomes unstable, and if it exceeds 3.0 degrees, it is different from the conventional steel cord having a 1 ⁇ 2 structure. This is because the effect of improving tire durability is not recognized.
- the steel cord forming rate it is necessary to limit the steel cord forming rate to 95 to 105% in terms of an average value (AVG).
- AVG average value
- the molding rate (AVG) is 95. If it is less than%, the shape of the steel cord becomes unstable, the fatigue resistance of the steel cord is reduced, and the tire durability deteriorates. If it is greater than 105%, the initial elastic modulus of the steel cord is reduced. This is because the tire durability decreases and the tire durability deteriorates.
- it is necessary to limit the steel cord forming rate to 5 to 20% with a standard deviation ⁇ .
- the standard deviation ⁇ of the molding rate is increased to create a local gap through which the coated rubber can penetrate, and the improved penetration of the coated rubber causes the wires to move apart and rub, resulting in fretting wear.
- the standard deviation ⁇ of the molding rate is smaller than 5%, it becomes impossible to create a local gap through which the coated rubber can penetrate, and the strands move apart. This is because if it exceeds 20%, the steel cord shape becomes unstable and the tire durability deteriorates.
- the wire diameter d of the steel cord is 0.28 to 0.35 mm for the reasons described above.
- the shape and dimensions of the micro-molding are not particularly limited, and any of the known micro-molding previously applied to the steel cord strands can be applied. It is also preferable that the shape is a wave shape and has a pitch of 1/2 to 1/20 of the cord twist pitch.
- the micro-molding is performed in advance by a molder.
- the pneumatic tire according to Embodiment 2 of the present invention is basically configured as described above.
- Example I When manufacturing pneumatic tires of tire size 145R12 with two belt layers with steel cords (1 ⁇ 2 ⁇ 0.30) driven in at a density of 40.0 / 50 mm, steel rods constituting the steel cords described above Steel cords with different carbon content, final wire drawing degree of steel cord, twist length, twist angle, cord strength, and cord strength in the tire as shown in Table 1 1. Seven types of pneumatic tires of Examples 1 and 2 and Comparative Examples 1 to 4 were produced.
- the final wire drawing degree is a value obtained by the formula 2 ⁇ ln (R1 / R2) where the plating wire diameter is R1 and the final wire diameter is R2.
- Example 1 is an example in which a high-tensile steel rod having a high carbon content is used as a material, and the cord strength satisfies the limited range of the present invention, but the carbon content and the twist angle are within the limited range of the present invention. It is not satisfied.
- Examples 1 and 2 are examples in which a steel rod having a low carbon content is used as a material, and the twist angle is varied within the range defined by the present invention within the range defined by the present invention.
- Comparative Examples 1 to 4 are examples in which the carbon amount of the steel rod is within the range defined by the present invention, but the twist angle or cord strength is outside the range defined by the present invention.
- Examples 1 and 2 maintained the durability performance equal to or higher than that of conventional tires. Comparative Example 1 had reduced strength, and Comparative Example 2 had reduced toughness. In Comparative Example 3, point contact fracture occurred, and in Comparative Example 4, the shape was unstable.
- Example II The effect of the pneumatic radial tire according to the second embodiment of the present invention was examined using a passenger car tire having a tire size of 145R12 and a rim size of 12 ⁇ 4.00B.
- a steel cord of 1 ⁇ 2 ⁇ 0.3HT is used as the steel cord of the first and second belts 22a and 22b of the belt layer 22 of the tire 10 shown in FIG. 1, and the cord driving density is 40.0 / 50 mm. .
- the carbon content of the steel rod of Conventional Example 2 the final wire drawing degree of the steel cord, the twist length of the steel cord in the tire, the twist angle, the cord strength and cord strength, and the average value of the molding rate And standard deviation (AVG, ⁇ ) are 0.82%, 3.5, 14.0 mm, 3.9 degrees, 450 N and 3183 MPa, and 96% and 2%, respectively.
- the average value (AVG) satisfies the limited range of the present invention
- the standard deviation ( ⁇ ) of the carbon content, the twist angle and the shaping rate does not satisfy the limited range of the present invention.
- the tire durability performance of the tires of Examples 2 and 4 and Comparative Example 5 was evaluated with the tire durability performance of the tire of Conventional Example 2 as 100.
- the final wire drawing degree of the steel cord is the method described in Example I, the twist length of the steel cord in the tire, the twist angle, the cord strength, the cord strength, the average value of the steel cord shaping rate and the standard.
- the deviation (AVG, ⁇ ) was obtained by the method described above.
- the tire durability performance was determined by the same method as in Example I described above. A running test was conducted until the evaluation tire broke down, and the tire durability performance was an index with the running distance of Conventional Example 2 as 100.
- the evaluation tires of Examples 3 and 4 have steel cord twist lengths of 20.0 mm and 25.0 mm, respectively. Since the average value and standard deviation (AVG, ⁇ ) of the angle and cord strength, and the molding rate satisfy the limited range and the preferable limited range of the present invention, the tire durability 100 of the evaluation tire of Conventional Example 2 is achieved. On the other hand, the tire durability is 102 and 105, respectively, and it can be seen that the durability performance of the tire is improved. Further, it can be seen that the evaluation tires of Examples 3 and 4 are further improved in the durability performance of the tire as compared with Examples 1 and 2 of Example I.
- Comparative Example 5 when the twist angle is 1.3, which is smaller than the limited range of the present invention and the twist length is 40 mm pitch, the shape becomes unstable and the tire durability becomes 99. It is worse than Conventional Example 2. From the above, the example of the present invention has an effect of improving tire durability as compared with Comparative Example 5, and the effect of the present invention is clear.
- the pneumatic tire of the present invention can improve the productivity while maintaining the fatigue resistance of the steel cord used for the reinforcing layer of the tire, and further improve the fatigue resistance of the steel cord. Since the tire durability performance can be improved, it is suitable for use as a pneumatic tire for vehicles, particularly as a radial tire for automobiles.
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Abstract
Description
例えば、特許文献1には、1×2×0.30HT撚り構造のスチールコードを使用したベルト層のベルト折れ、ベルト層のセパレーション耐久性を維持するために、カーボン含有量が0.82重量%の線材を使用し、コード角度を23°にし、コードエンドを47.25(本/50mm)にした空気入りラジアルタイヤが開示されている。
本出願人の出願に係る特許文献4では、予め螺旋状に型付した2本の素線を撚り合わせた1×2構造のスチールコードによって補強層を構成する際に、スチールコードの撚りの位相長さp1を型付素線の螺旋の位相長さp2以上(p2 ≦p1)、撚りの位相高さd1を型付素線の螺旋の位相高さd2より大きく、かつ素線の直径Dの3倍以下とする(d2 <d1 ≦3D)ことにより、スチールコードの被覆ゴムの浸透性を向上させ、フレッティング現象を少なくすることにより、良好な耐屈曲疲労性及び耐圧縮疲労性を得ることができるとしている。
また、特許文献6では、補強部材として用いられるスチールコードでの撚り角度をθとし、層芯径をDとした場合に、最小撚りピッチPmin が、式 Pmin =πD・ tan{(90-θ)π/180}を満たし、さらに、使用時におけるコードの曲率半径をRとし、コードのカット長さをLとした場合に、最大撚りピッチPmax がPM r=2πRまたはPM l=Lのいずれか小さいほうで与えられるようにすることにより、曲げた状態であっても全体に均一に荷重がかかり、撚り減りが小さく、高い強度を得ることができ、伸び率が大きいロングピッチのスチールコードとすることができるとしている。
このような問題の対策としては、伸線加工度を大きくしやすい、柔らかい低カーボン含有量のスチールロッドを素材として使用し、その中間伸線加工度を高くした強加工を行う方法がある。こうすることで、スチール組織の配向性が増加するため、スチールコードの強度を高カーボン含有量のスチールを使用した場合と同レベルにすることができる。しかし、強度は従来の高カーボン含有量のスチールコード並みにできても、スチール素材が柔らかいために、使用中に1×2撚り構造スチールコード中のワイヤ素線同士が点接触することにより、スチールコードの耐疲労性が低下するという問題があった。
また、特許文献5では、1×2構造のスチールコードの型付率及び撚りピッチ等を上記関係にすることにより、素線の周囲を実質的に完全にゴム被覆して、軽量化と同時に、耐錆性と耐衝撃性とを良好にしているが、スチールコードの撚角が適切に規定されておらず、型付率の規定も十分とは言えないために、耐疲労性の向上が十分であると言えないという問題があった。
さらに、1×2構造のスチールコードの耐疲労性を向上させるために、スチールコードの撚長さを長くして、素線同士を、「点接触」から「線接触」にして、素線間の隙間を減らして被覆ゴムの浸透を向上させることが考えられるが、線接触する部分はゴムに被覆されないので、単に、撚長さを長くするだけでは、素線同士がばらばらに動いて擦れ易くなり、フレッティング摩耗が生じ、耐疲労性は、向上しないという問題があった。
その結果、上記の従来技術においては、1×2構造のスチールコードを補強層として使用した空気入りラジアルタイヤのタイヤ耐久性を向上させることができないという問題があった。
また、本発明の他の目的は、上記目的に加え、空気入りラジアルタイヤに用いる1×2構造のスチールコードの撚り角及び型付き率の平均値並びに標準偏差σを適切に規定することにより、スチールコードの耐疲労性を向上させ、その結果、タイヤの耐久性能を向上させることができる空気入りラジアルタイヤを提供することにある。
また、前記スチールコードの前記ワイヤ素線の径が、0.28~0.35mmであることが好ましい。
また、前記スチールコードの撚長さが、18~40mmであることが好ましい。
また、前記補強層が、ベルト層及び/又はサイド補強層であることが好ましい。
また、前記スチールコードの2本の前記ワイヤ素線の内の少なくとも1本の素線が、微小癖付けを施したものであることが好ましい。
また、前記空気入りタイヤが、空気入りラジアルタイヤであることが好ましい。
すなわち、本発明は、例えば、低カーボン含有量の線材の強加工及び低撚り角化ができていないスチールコードを用いる特許文献1の空気入りタイヤに対して、空気入りタイヤのスチールコードの耐疲労性及び生産性において優れた効果を持つ。
図1は、本発明の空気入りタイヤの一実施形態の子午線CLに対して右半分の断面形状を示す断面図である。
図1に示す空気入りタイヤ(以下、単にタイヤという)10は、空気入りラジアルタイヤであって、トレッド部12と、ショルダー部14と、サイドウォール部16と、ビード部18と、を主な構成部分として有する。図1中で示されていないタイヤ左半分についても、同様の構成を有する。
なお、以下の説明において、タイヤ幅方向とは、図1中に矢印aで示す、タイヤの回転軸と平行な方向をいい、タイヤ径方向とは、図1中に矢印bで示す、回転軸と直交する方向をいう。また、タイヤ周方向とは、回転軸を回転の中心となる軸として回転する方向をいう。さらに、タイヤ内側とは、タイヤ径方向において図1中タイヤの下側、すなわちタイヤに所定の内圧を与える空洞領域Rに面するタイヤ内面側をいい、タイヤ外側とは、図1中タイヤの上側、すなわちタイヤ内周面と反対側の、ユーザが視認できるタイヤ外面側をいう。
以下、タイヤ10の各要素について詳細に説明する。
また、本実施形態では、ベルト層22の1番ベルト22a及び2番ベルト22bの両方に、本発明によるスチールコードを適用しているが、本発明はこれに限定されず、一方のみに本発明によるスチールベルトを適用しても良いし、後述するサイド補強層26に本発明が適用される場合には、両方共に、本発明によるスチールベルトを適用せず、従来公知のスチールベルトやポリエステル、ナイロン、芳香族ポリアミド等からなる有機繊維コード等からなる従来公知の補強コードを用いても良い。
例えば、タイヤ10は、図1に示すように、ベルト層22をタイヤ幅方向に端から端まで覆う層24aと、その外側にベルト層22の端部を覆う層24bとからなるベルトカバー層24から構成されている。
また、ビード部18には、タイヤ周方向に対して傾斜する補強コードを含むサイド補強層26が埋設されている。
なお、サイド補強層26の他端部Cは、カーカス層20の本体部20aとビードフィラー6との間の、ビードコア28近傍に存在する。なお、サイド補強層26は、ビード部18では、カーカス層20の折り返し部20bとビードコア28及び/又はビードフィラー30との間に、サイドウォール部16では、本体部20aと折り返し部20bとの間に配置されていても良いし、ビード部18では、折り返し部20bのタイヤ幅方向外側に、サイドウォール部16では、本体部20aの外側に配置されていても良い。さらに、これらを組み合わせて配置しても良い。
また、本実施形態では、サイド補強層26に、本発明によるスチールコードを適用しているが、本発明は特にこれに限定されず、上述したベルト層22に本発明が適用される場合には、本発明によるスチールベルトを適用せず、従来公知のスチールベルトやポリエステル、ナイロン、芳香族ポリアミド等からなる有機繊維コード等からなる従来公知の補強コードを用いても良い。
さらに、サイド補強層26を設ける領域を補強コードの種類に応じて変えても良い。例えば、サイド補強層26の補強コードとして、本発明によるスチールコードや、従来公知のスチールコードを用いる場合には、ビードフィラー30とカーカス層20の折り返し部20bとの間にサイド補強層26を配置するのが好ましく、有機繊維コードを用いる場合には、ビードコア28及びビードフィラー30を包み込むようにサイド補強層26を配置するのが好ましい。
本発明の実施形態1に係る空気入りタイヤは、基本的に以上のように構成される。
本発明の実施形態2の空気入りタイヤは、実施形態1の空気入りタイヤにおいて、さらに、スチールコードの撚り角及び型付き率の平均値並びに標準偏差σを適切に規定することにより、実施形態1におけるスチールコードの生産性の向上を低下させることなく維持したまま、スチールコードの耐疲労性をさらに向上させ、その結果、タイヤの耐久性能を向上させることができるものである。
なお、本発明の実施形態2の空気入りタイヤの構成は、スチールコード撚り角及び型付き率の平均値並びに標準偏差σを除いて同一の構成を有するものであるので、同一の構成についての説明は省略し、主として異なる点について説明する。
本実施形態は、2本のワイヤ素線(以下、単に素線ともいう)を撚り合わせた1×2構造のスチールコードをタイヤの補強層に使用するものであって、スチールコードのカーボン含有量が、0.60~0.75%であり、タイヤに埋設された状態でのスチールコードの強度が、2900~3500MPaであり、タイヤ中におけるスチールコードの撚角(撚角度α)が、1.5~3.0度であり、スチールコードの型付率が、平均値で95~105%、標準偏差σで、5~20%であることを特徴とするものである。
なお、スチールコードのカーボン含有量、タイヤに埋設された状態でのスチールコードの強度及びタイヤ中におけるスチールコードの撚角度α(以下、単に撚角ともいう)についての説明は、実施形態1と同様であるので、その詳細な説明を省略する。
すなわち、図3(a)示すスチールコード50は、2本のワイヤ素線52を隙間なく撚り合わせたものであるので、スチールコード50のコード外径D1は、ワイヤ素線52の直径(素線径)dの2倍の2d(D1=2d)となる。例えば、1×2×0.30HTのスチールコードのコード外径D1は、素線径dが0.30mmであるので、0.60mm(=0.30×2)となる。
一方、2本のワイヤ素線52を隙間なく撚り合わせたスチールコード50であっても、撚り合わせられた2本のワイヤ素線52を個々に取り出すと、図3(b)に示すように、螺旋状の型付けされた状態となるが、撚り合わせた状態から伸縮しているので、螺旋の包絡線の外径であるスパイラル外径H1は、所定の値となる。このスパイラル外径H1を求めることにより、スチールコードの型付率は、計算式(H1/D1)×100を計算することにより求めることができる。
1)まず、タイヤから、スチールコードを取出す。
2)カッターナイフで、スチールコードの外側のゴムを除去する。
3)スチールコードをアセトンに浸漬し、(コードを簡単にばらせる様になるまで、)加熱する。
4)素線を塑性変形させないように気を付けながら、スチールコードをばらして、個々の素線を取り出す。
5)1本の素線について、タイヤセンターに位置する部分にて、投影機で連続4つの素線波高(mm)を測定する。
6)連続4つの素線波高の平均値をH1とし、予め素線径から求めておいたコード外径D1を用いて、上記式(H1/D1)×100から、型付率(%)を算出する。
7)もう一方の素線についても、同様にして型付率を求める。
8)タイヤの周上8ヶ所にて、同様の試験を実施する。
9)スチールコード8本(したがって、素線16本)の型付率を求め、スチールコードの型付率(AVG、σ)を算出する。
こうして、型付率の平均値(AVG)及び標準偏差σを算出することができる。
1)まず、タイヤから、スチールコードを取出す。
2)カッターナイフで、スチールコードの外側のゴムを除去する。
3)コード径、撚長さを測定する。
4)スチールコードをばらし、カッターナイフで、素線間のゴムを除去する。
5)素線径を測定する。
6)タイヤの周上8ヶ所にて、同様の試験を実施する。
7)下記式にて、スチールコード8本の撚角を算出し、平均値を撚角とする。
撚角(度α) = 180 /π * arctan( π * 層心径 / 撚長さ )
層心径 = コード径 -素線径
したがって、本実施形態においても、スチールコードの撚角を、1.5~3.0度の範囲に限定しているのである。その理由は、上述したように、スチールコードの撚角が、1.5度未満では、スチールコードの形状が不安定となり、3.0度超では、従来の1×2構造のスチールコードからのタイヤ耐久性の向上効果が認められないからである。
また、本実施形態において、スチールコードの型付率を、標準偏差σで、5~20%に限定する必要がある。その理由は、型付率の標準偏差σを大きくして、被覆ゴムが浸透できる局所隙間を作り、被覆ゴムの浸透の向上によって、素線同士がばらばらに動いて擦れて、フレッティング摩耗が生じることを防止することができるからであり、具体的には、型付率の標準偏差σを、5%よりも小さくすると、被覆ゴムが浸透できる局所隙間を作れなくなり、素線同士がばらばらに動くからであり、20%よりも大きくすると、スチールコード形状が不安定になり、タイヤ耐久性が悪化するからである。
また、本発明においては、スチールコードの少なくとも1本の素線には、予め微小癖付けを施しておくのが好ましい。その理由は、被覆ゴムが浸透できる局所隙間を作り易くできるからである。
本発明においては、微小型付けの形状や寸法は、特に制限的ではなく、従来、スチールコードの素線に予め施されている公知の微小型付けは、いずれも適用可能であるが、例えば、螺旋状や波形状の形状であって、コード撚りピッチの1/2~1/20のピッチのものが好ましい。
なお、微小型付けは、予め型付け機によって施しておくのが好ましい。
本発明の実施形態2に係る空気入りタイヤは、基本的に以上のように構成される。
スチールコード(1×2×0.30)を打ち込み密度40.0本/50mmで配置したベルト層を2枚設けたタイヤサイズ145R12の空気入りタイヤを製造するにあたり、上記スチールコードを構成するスチールロッドのカーボン含有量、スチールコードの最終伸線加工度、タイヤ中におけるスチールコードの撚長さ、撚角度、コード強力、及びコード強度を表1のように異ならせたスチールコードを使用し、従来例1、実施例1~2、比較例1~4の7種類の空気入りタイヤを製造した。
各評価タイヤをリムサイズ12×4.00Bのリムにリム組みし、空気圧170kPaを充填し、直径1707mmの回転ドラム上で、荷重を3.2±2.1kN、スリップ角を0±4°として、荷重とスリップ角を0.067Hzで矩形波変動させながら、速度25km/hで走行させた。評価タイヤが故障するまで走行試験し、走行距離を測定した。従来例1の走行距離を100として指数で示した。指数値が大きいほどタイヤ耐久性能が優れている。
タイヤサイズ145R12、リムサイズ12×4.00Bの乗用車用タイヤで、本発明の実施形態2の空気入りラジアルタイヤの効果を調べた。
図1に示すタイヤ10のベルト層22の1番及び2番ベルト22a及び22bのスチールコードとして、1×2×0.3HTのスチールコードを用い、コード打込み密度を40.0本/50mmとした。
表2に示すように、スチールコードを構成するスチールロッドのカーボン含有量、スチールコードの最終伸線加工度、タイヤ中におけるスチールコードの撚長さ、撚角度、コード強力及びコード強度、並びに型付率の平均値及び標準偏差(AVG、σ)を変えて、従来例2、実施例3及び4、並びに比較例5の評価タイヤを作製し、各評価タイヤのタイヤ耐久性能を測定した。その結果を表2に示す。
表2中、従来例2のスチールロッドのカーボン含有量、スチールコードの最終伸線加工度、タイヤ中のスチールコードの撚長さ、撚角度、コード強力及びコード強度、並びに型付率の平均値及び標準偏差(AVG、σ)は、それぞれ、0.82%、3.5、14.0mm、3.9度、450N及び3183MPa、並びに96%及び2%であり、コード強度、型付率の平均値(AVG)は、本発明の限定範囲を満たすものの、カーボン含有量、撚角度及び型付率の標準偏差(σ)は、本発明の限定範囲を満たさないものであった。この従来例2のタイヤのタイヤ耐久性能を100として、実施例3及び4、並びに比較例5のタイヤのタイヤ耐久性能を評価した。
また、タイヤ耐久性能は、上述した実施例Iと同じ方法によって求めた。
評価タイヤが故障するまで走行試験し、タイヤ耐久性能を従来例2の走行距離を100とした指数でした。
以上から、本発明の実施例には、比較例5に比べて、タイヤ耐久性の向上効果があり、本発明の効果は、明らかである。
12 トレッド部
14 ショルダー部
16 サイドウォール部
18 ビード部
20 カーカス層
22 ベルト層
22a 内側ベルト層
22b 外側ベルト層
24 ベルトカバー層
26 サイド補強層
28 ビードコア
30 ビードフィラー
32 トレッドゴム層
34 サイドウォールゴム層
36 リムクッションゴム層
38 インナーライナゴム層
40、50 スチールコード
42、52 ワイヤ素線(素線)
44 ブラス鍍金層
Claims (8)
- 2本のワイヤ素線を撚り合わせた1×2構造のスチールコードを補強層に使用した空気入りタイヤであって、
前記スチールコードのカーボン含有量が、0.60~0.75%であると共に、前記タイヤ中における前記スチールコードの強度が、2900~3500MPaで、且つ、前記スチールコードの撚角度が、1.5~3.0°であることを特徴とする空気入りタイヤ。 - 前記スチールコードの前記ワイヤ素線の外表面に形成されたブラス鍍金層の厚さが、0.25~0.32μmである請求項1に記載の空気入りタイヤ。
- 前記スチールコードの前記ワイヤ素線の径が、0.28~0.35mmである請求項1又は2に記載の空気入りタイヤ。
- 前記スチールコードの撚長さが、18~40mmである請求項1~3のいずれか1項に記載の空気入りタイヤ。
- 前記補強層が、ベルト層及び/又はサイド補強層である請求項1~4のいずれか1項に記載の空気入りタイヤ。
- 前記スチールコードの型付率が、平均値で95~105%、標準偏差σで、5~20%である請求項1~5のいずれか1項に記載の空気入りタイヤ。
- 前記スチールコードの2本の前記ワイヤ素線の内の少なくとも1本の素線が、微小癖付けを施したものである請求項6に記載の空気入りタイヤ。
- 前記空気入りタイヤが、空気入りラジアルタイヤである請求項1~7のいずれか1項に記載の空気入りタイヤ。
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DE112010004043.5T DE112010004043B4 (de) | 2009-10-16 | 2010-10-15 | Stahlcord für einen Luftreifen |
CN201080056968.6A CN102666134B (zh) | 2009-10-16 | 2010-10-15 | 充气轮胎 |
US13/497,122 US20120193006A1 (en) | 2009-10-16 | 2010-10-15 | Pneumatic tire |
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JP2009-239753 | 2009-10-16 | ||
JP2009239753A JP4683150B2 (ja) | 2009-10-16 | 2009-10-16 | 空気入りタイヤ |
JP2010075053A JP4683155B1 (ja) | 2010-03-29 | 2010-03-29 | 空気入りラジアルタイヤ |
JP2010-075053 | 2010-03-29 |
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CN (1) | CN102666134B (ja) |
DE (1) | DE112010004043B4 (ja) |
WO (1) | WO2011046195A1 (ja) |
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CN104684741A (zh) * | 2012-09-04 | 2015-06-03 | 大陆轮胎德国有限公司 | 充气车辆轮胎、优选充气商用车辆轮胎 |
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WO2014060819A1 (en) * | 2012-10-18 | 2014-04-24 | Kordsa Global Endüstriyel Iplik Ve Kord Bezi Sanayi Ve Ticaret Anonim Sirketi | A reinforcing belt package for radial vehicle tires |
WO2014083535A2 (en) * | 2012-11-30 | 2014-06-05 | Pirelli Tyre S.P.A. | Reinforcement cord and tyre for vehicle wheels comprising such a reinforcement cord |
MX2016015082A (es) * | 2014-05-30 | 2017-02-28 | Pirelli | Neumatico para ruedas de vehiculo. |
FR3032149B1 (fr) | 2015-02-03 | 2017-02-17 | Michelin & Cie | Pneu radial ayant une structure de ceinture tres fine |
JP6510353B2 (ja) * | 2015-07-29 | 2019-05-08 | Toyo Tire株式会社 | 空気入りタイヤ及びその製造方法 |
JP2019035461A (ja) * | 2017-08-15 | 2019-03-07 | 株式会社ブリヂストン | 高圧ホース |
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CN102666134B (zh) | 2015-04-15 |
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