WO2014038689A1 - 空気入りタイヤ用トレッド及びこのトレッドを有する空気入りタイヤ - Google Patents
空気入りタイヤ用トレッド及びこのトレッドを有する空気入りタイヤ Download PDFInfo
- Publication number
- WO2014038689A1 WO2014038689A1 PCT/JP2013/074229 JP2013074229W WO2014038689A1 WO 2014038689 A1 WO2014038689 A1 WO 2014038689A1 JP 2013074229 W JP2013074229 W JP 2013074229W WO 2014038689 A1 WO2014038689 A1 WO 2014038689A1
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- WIPO (PCT)
- Prior art keywords
- block
- tread
- front side
- pneumatic tire
- reinforcing portion
- Prior art date
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- 230000003014 reinforcing effect Effects 0.000 claims description 87
- 239000000463 material Substances 0.000 claims description 21
- 229920001971 elastomer Polymers 0.000 claims description 20
- 239000000203 mixture Substances 0.000 claims description 14
- 238000009864 tensile test Methods 0.000 claims description 4
- 238000005096 rolling process Methods 0.000 claims description 3
- 230000000694 effects Effects 0.000 description 14
- 230000002787 reinforcement Effects 0.000 description 11
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 9
- 230000015572 biosynthetic process Effects 0.000 description 5
- 239000000025 natural resin Substances 0.000 description 5
- 238000003860 storage Methods 0.000 description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 230000001133 acceleration Effects 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 230000009477 glass transition Effects 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 239000004745 nonwoven fabric Substances 0.000 description 2
- 239000002759 woven fabric Substances 0.000 description 2
- 101100008050 Caenorhabditis elegans cut-6 gene Proteins 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 239000006229 carbon black Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 229920003244 diene elastomer Polymers 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000002657 fibrous material Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
- 229920005992 thermoplastic resin Polymers 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
- 239000004636 vulcanized rubber Substances 0.000 description 1
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
- B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
- B60C11/0041—Tyre tread bands; Tread patterns; Anti-skid inserts comprising different tread rubber layers
-
- 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
- B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
- B60C11/03—Tread patterns
- B60C11/11—Tread patterns in which the raised area of the pattern consists only of isolated elements, e.g. blocks
-
- 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
- B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
- B60C11/0008—Tyre tread bands; Tread patterns; Anti-skid inserts characterised by the tread rubber
-
- 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
- B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
- B60C11/03—Tread patterns
- B60C11/12—Tread patterns characterised by the use of narrow slits or incisions, e.g. sipes
-
- 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
- B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
- B60C11/03—Tread patterns
- B60C11/13—Tread patterns characterised by the groove cross-section, e.g. for buttressing or preventing stone-trapping
- B60C11/1307—Tread patterns characterised by the groove cross-section, e.g. for buttressing or preventing stone-trapping with special features of the groove walls
- B60C11/1346—Tread patterns characterised by the groove cross-section, e.g. for buttressing or preventing stone-trapping with special features of the groove walls covered by a rubber different from the tread rubber
-
- 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
- B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
- B60C11/03—Tread patterns
- B60C11/13—Tread patterns characterised by the groove cross-section, e.g. for buttressing or preventing stone-trapping
- B60C11/1376—Three dimensional block surfaces departing from the enveloping tread contour
-
- 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
- B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
- B60C11/03—Tread patterns
- B60C11/13—Tread patterns characterised by the groove cross-section, e.g. for buttressing or preventing stone-trapping
- B60C11/1376—Three dimensional block surfaces departing from the enveloping tread contour
- B60C11/1392—Three dimensional block surfaces departing from the enveloping tread contour with chamfered block edges
-
- 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
- B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
- B60C11/0008—Tyre tread bands; Tread patterns; Anti-skid inserts characterised by the tread rubber
- B60C2011/0016—Physical properties or dimensions
- B60C2011/0025—Modulus or tan delta
-
- 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
- B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
- B60C11/03—Tread patterns
- B60C11/12—Tread patterns characterised by the use of narrow slits or incisions, e.g. sipes
- B60C11/1204—Tread patterns characterised by the use of narrow slits or incisions, e.g. sipes with special shape of the sipe
- B60C2011/1209—Tread patterns characterised by the use of narrow slits or incisions, e.g. sipes with special shape of the sipe straight at the tread surface
Definitions
- the present invention relates to a tread for a pneumatic tire and a pneumatic tire having the tread, and in particular, a tread for a pneumatic tire having improved performance on snow and on ice by a reinforcing portion provided on a front side wall of a block, and the tread.
- the present invention relates to a pneumatic tire.
- Winter tires also called studless tires, are well known as tires that can run on winter roads covered with snow and ice. Winter tires generally use multiple soft cuts compared to non-winter tires, with so-called edge effects and water film removal effects, with multiple narrow cuts called sipes that open to the ground plane This improves the adhesion to the road surface in winter.
- the mechanism that generates frictional force with the road surface in winter tires is actually different depending on whether the road surface is snow or ice, so a soft compound is used to improve the performance on ice, and the block is a grounding element. It is known that even if a large number of thin slits are provided, the block rigidity is lowered as a result, and the improvement of performance on snow is hindered.
- Patent Document 1 mainly FIG. 3
- a block provided with three thin notches and one sub-groove has a JIS A hardness of 80 on the side wall of the block facing the lateral groove and the sub-groove.
- a pneumatic tire is described in which a reinforcing part using 95 ° rubber is provided to achieve both on-snow performance and on-ice performance.
- Patent Document 2 (mainly FIG. 2) describes at least one selected from carbon black and silica in 100 parts by weight of a diene rubber containing 30% by weight or more of a rubber component having a glass transition temperature of ⁇ 60 ° C. or more.
- the air is made to have both on-snow performance and on-ice performance by providing a reinforcing part using rubber with a brittle temperature of -30 ° C or lower on the side wall of the block. Entered tires are described.
- Patent Document 3 (mainly FIG. 1), which is a prior application, a reinforcing layer (reinforcing portion) having a modulus (elastic modulus) of a material of 200 MPa or more over an area of 50% or more of the side wall of the block is less than 0.5 mm.
- the tread for a pneumatic tire is described in which the performance on the snow and the performance on the ice are made compatible with each other by providing the thickness.
- JP 7-047814 A JP 2010-105509 A PCT / JP2011 / 079188 (International Publication No. 2013/088570 Pamphlet)
- Patent Document 1 Patent Document 2 and Patent Document 3
- From the viewpoint of safety there is a demand for a pneumatic tire that can achieve both higher performance on snow and higher performance on ice.
- the present invention has been made to solve the above-described problems of the prior art, and includes a tread for a pneumatic tire that can achieve both higher performance on snow and higher performance on ice, and such a tread.
- An object is to provide a pneumatic tire having the same.
- the present invention provides a tread for a pneumatic tire formed of at least one rubber composition, wherein the at least one rubber composition is a tensile test specified in the standard ASTM D882-09.
- the tread has at least one circumferential main groove, a plurality of sub grooves, and a plurality of blocks separated by the circumferential main grooves and sub grooves.
- at least one block of the plurality of blocks includes an upper surface, a part of which is in contact with the road surface at the time of tire rolling, two front side walls positioned along the tire circumferential direction, and a tire axial direction.
- the top surface of the block has two front edges formed at positions intersecting the two front side walls, and the block has two front side walls
- the difference G between the distance Rt measured from the tire rotation axis to the outermost radial position on the upper surface and the distance Re measured from the tire rotation axis to the two front edges is 0.2 when new. It is characterized by being not less than 2.0 mm and not more than 2.0 mm, and the distance between the most radially outer position of the reinforcing portion and the front edge is not more than 2.0 mm.
- the “groove” refers to a width and a width formed by connecting two opposing surfaces (wall surface, side wall) that do not come into contact with each other under normal use conditions by another surface (bottom surface). Say a space with depth.
- the “main groove” refers to a groove having a relatively wide width among various grooves formed in the tread, which mainly handles fluid drainage.
- the main groove means a groove extending in the tire circumferential direction in a straight line, zigzag shape or wave shape in many cases, but has a relatively wide width mainly extending the drainage of the fluid extending at an angle with respect to the tire rotation direction. Grooves with are also included. Further, grooves other than the “main groove” are called “sub-grooves”.
- the “edge” refers to an intersection between the upper surface of the block and the front side wall or the side wall (each edge of the upper surface of the block, or a boundary between the front side wall or the side wall on the upper surface of the block).
- the upper surface of the block a part of which is a ground plane, is partitioned by such an edge.
- a chamfer is formed between the upper surface and the front side wall or the side wall, such a chamfer is interpreted as a part of the upper surface.
- the edges that define the upper surface of the block the intersection between the upper surface of the block and the front side wall on the rotation direction side is referred to as a “front edge”.
- the front edge contacts the road surface under specific road surface conditions.
- the “elastic modulus” means a tensile elastic modulus E calculated from a tensile test curve obtained from a tensile test specified in the standard ASTM D882-09.
- This tensile elastic modulus E has the following relationship with the shear elastic modulus G as described in, for example, “POLYMER PHYSICS” (Oxford, ISBN 978-0-19-852059-7, Chapter 7.7, Page 296).
- ⁇ is a Poisson's ratio
- the Poisson's ratio of the rubber material is very close to 0.5.
- the elastic modulus Ef of the material forming the reinforcing portion is at least 20 times higher than the elastic modulus Et of the rubber composition forming the tread, etc.
- the above-described elastic modulus Et and elastic modulus Ef are complex
- the elastic modulus (dynamic shear modulus of the material, dynamic shear modulus: G *) can be confirmed by replacing each with M.
- a known dynamic property, the storage modulus represented by G ′ and the loss modulus represented by G ′′, are specimens molded from the raw composition by a viscosity analyzer (viscoanalyzer: Metravib VB4000).
- test piece bonded with the vulcanized composition which is of the standard ASTM D 5992-96 (published in September 2006, originally approved in 1996).
- the one described in Figure X2.1 (a circular method) is used.
- the test piece diameter “d” is 10 mm (thus the test piece has a circular cross section of 78.5 mm 2 ), and the rubber compound
- the thickness “L” of each part is 2 mm and the ratio “in contrast to the ratio“ d / L ”2 recommended by the standard ISO 2856, described in paragraph X2.4 of the ASTM standard” d / L "is set to 5.
- the distance from the tire rotation axis to the region excluding the two front edges on the upper surface is greater than the distance Re from the tire rotation axis to the two front edges measured, and the tire rotation Since the difference G between the distance Rt to the outermost position of the upper surface of the block measured from the axis and the distance Re to the two front edges measured from the rotation axis is 0.2 mm or more when new, it looks like on ice
- the front edge formed at the intersection of the block upper surface and the front side wall provided with the reinforcing portion must be in contact with the road surface. Can be prevented.
- the difference G is 2.0 mm or less
- a block upper surface and a reinforcing portion are provided.
- a high edge pressure can be locally obtained by bringing the front edge formed at the intersection with the formed front side wall into contact with the road surface. That is, due to the effect of the reinforcing portion provided on the front side wall, the front edge can be taken into the snow effectively, and as a result, the performance on snow can be improved.
- this difference G is larger than 2.0 mm, it will be difficult to bring the front edge into contact with the road surface, even on a road surface where the friction coefficient of the road surface is high enough to deform the grounding element as on ice. As a result, it becomes difficult to cause the front edge to penetrate into the snow, which may reduce the performance on snow.
- the friction coefficient of the road surface is sufficient to deform the grounding element as on snow.
- the road surface has a coefficient of friction that is sufficiently high to deform the grounding element as on snow. Even if the front edge portion is in contact with the road surface, it is difficult to generate a high edge pressure locally, which may reduce the performance on snow.
- the reinforcement part provided in the front side wall is provided in the front edge so that it may extend in at least one part of the width direction of a front edge.
- the present invention configured as described above, on the snow, it is possible to reliably obtain a locally high edge pressure due to the front edge due to the effect of the reinforcing portion. As a result, while improving the performance on ice, Performance can be improved.
- the reinforcement part provided in the front side wall is provided so that it may extend over the front edge width direction in a front edge.
- a locally high edge pressure by the front edge can be reliably obtained.
- the difference G on the upper surface of the block is preferably 1.5 mm or less.
- the present invention configured as described above it is possible to more reliably obtain a locally high edge pressure due to the front edge on the snow, and as a result, improve the performance on snow while improving the performance on ice. I can do it.
- the reinforcing portion provided on the front side wall of the block is provided on both of the two front side walls of the block.
- locally high edge pressure is generated by the front edge formed at the intersection of the block upper surface and the front side wall provided with the reinforcing portion at the time of acceleration and deceleration on snow. As a result, the performance on snow can be further improved while improving the performance on ice.
- an angle between a straight line connecting the two front edges and a tangent line of the upper surface passing through the front edges is 20 degrees or more.
- the front edge when traveling on a road surface where the friction coefficient of the road surface is insufficient to deform the grounding element, such as on ice, the front edge is prevented from coming into contact with the road surface, As a result, sufficient contact between a part of the upper surface of the block and the road surface can be ensured, and as a result, the performance on ice can be further improved. In other words, if this angle is less than 20 degrees, the front edge cannot be reliably prevented from coming into contact with the road surface, and the performance on ice may be degraded.
- the reinforcing portion provided on the front side wall of the block is provided over a region of 75% or more of the front side wall.
- the present invention configured as described above, it is possible to more reliably obtain a locally high edge pressure due to the front edge formed at the intersection of the block upper surface and the front side wall provided with the reinforcing portion on the snow. As a result, it is possible to improve the performance on snow while improving the performance on ice.
- the reinforcement part provided in the front side wall of the block is provided over the whole area
- the performance on snow can be improved more reliably while improving the performance on ice.
- the block is preferably formed so that an average distance in the tire circumferential direction between two front edges is 15 mm or more.
- the present invention configured as described above, it is possible to prevent the block from being deformed even when traveling on a road surface where the friction coefficient of the road surface is insufficient to deform the grounding element as on ice. As a result, the generation of a water film between the tread and ice can be prevented, and as a result, the performance on ice can be further improved.
- the block further has a narrow notch that opens to the upper surface and extends inward of the block and extends in the tire width direction.
- narrow cut means a cut formed by a knife blade, which is also called a sipe, and the width of the thin cut on the tread surface is mainly smaller than the minor groove. Is relatively small, approximately 2 mm or less.
- the narrow notch partially reduces the block rigidity that is generally increased by the reinforcing portion, thereby improving the adhesion with the road surface, particularly with the road surface on ice. As a result, the performance on ice can be improved.
- the narrow notch can help block deformation when traveling on a road surface where the coefficient of friction of the road surface is high enough to deform the grounding element, such as on snow, and locally increases the edge pressure due to the front edge. Furthermore, the front edge portion can be sufficiently absorbed into the snow, and as a result, the performance on snow can be further improved. Also, as a well-known phenomenon, a thin notch is well known as one of the causes of lowering the coefficient of friction on ice, and is an additional storage for removing the water film generated between the tread and ice. It can act as a region, and as a result, the performance on ice can be further improved.
- the performance on snow and the performance on ice can be made compatible at a higher level.
- FIG. 1 is a perspective view schematically showing a tread for a pneumatic tire according to a first embodiment of the present invention. It is an expanded sectional view of the block of the tread for pneumatic tires seen along the II-II line of FIG. It is an expanded sectional view of the block of the tread for pneumatic tires by a 2nd embodiment of the present invention. It is an expanded sectional view of the block of the tread for pneumatic tires by a 3rd embodiment of the present invention. It is an expanded sectional view of the block of the conventional tread for pneumatic tires.
- FIG. 1 is a perspective view schematically showing a tread for a pneumatic tire according to a first embodiment of the present invention
- FIG. 2 is a block diagram of the tread for a pneumatic tire seen along line II-II in FIG. FIG.
- reference numeral 1 denotes a tread for a pneumatic tire according to the first embodiment of the present invention.
- the example of the tire size of the pneumatic tire to which this tread 1 for pneumatic tires is applied is 205 / 55R16.
- the tread 1 is made of a rubber composition having an elastic modulus Et, has a ground contact surface 2 that comes into contact with the road surface when the tire rolls, and is formed with two circumferential main grooves 3 and a plurality of sub grooves 4. .
- a plurality of blocks 5 are defined by the circumferential main grooves 3 and the sub-grooves 4.
- the block 5 has an upper surface 51 that forms part of the ground contact surface 2 and two side walls (front side walls) that are positioned in the longitudinal direction along the tire circumferential direction and face the sub-groove 4. 52 and 53 and two side walls (side walls) 54 and 55 which are located in the lateral direction along the tire rotation axis direction and are formed so as to face the circumferential groove 3.
- the upper surface 51 forms front edges 521 and 531 at edges that intersect with the front side walls 52 and 53.
- the block 5 is formed with a thin notch 6 that opens in the upper surface 51 and extends in the tire width direction and extends inward in the radial direction of the block 5.
- the narrow cut 6 is also opened in the side walls 54 and 55.
- the thin notch 6 may extend at a predetermined angle with respect to the radial direction within a range in which various functions are exhibited.
- the “tire width direction” is a direction perpendicular to the tire circumferential direction in the present embodiment, but includes a direction extending obliquely with a predetermined angle with respect to the tire circumferential direction.
- the two front side walls 52 and 53 are provided with reinforcing portions 7 made of a material having an elastic modulus Ef that is at least 20 times higher, preferably at least 50 times higher than the elastic modulus Et of the rubber composition forming the tread 1. It has been.
- the elastic modulus Et of the rubber composition forming the tread 1 is 5.4 MPa
- the material forming the reinforcing portion 7 is a material based on natural resin, and its elastic modulus is 270 MPa.
- the elastic modulus Ef is formed to be 50 times higher than the elastic modulus Et.
- each reinforcement part 7 is provided so that 60% or more of the front side walls 52 and 53, Preferably it is 75% or more, More preferably, it faces the subgroove 4 over all the area
- Each reinforcing portion 7 is provided so that the average thickness t (shown in FIG. 2) is less than 2.0 mm, preferably less than 1.0 mm.
- the thickness of the reinforcing portion 7 is a thickness in a direction perpendicular to the surface facing the sub-groove 4 of the front side walls 52 and 53 where the reinforcing portion 7 is provided, and the “average thickness” is the reinforcing portion.
- the reinforcing portion 7 is provided over an area of 84% of the front side walls 52 and 53, and the average thickness t is 0.5 mm.
- the average thickness t of the reinforcing portion 7 is preferably 0.2 mm or more.
- the upper surface 51 of the block 5 of the tread 1 forms a part of the ground contact surface 2 of the tread 1 that comes into contact with the road surface when the tire rolls, and the upper surface 51 is a region of the block 5 that can be in contact with the road surface under a specific condition. Defined.
- the upper surface 51 is limited by two circumferential edges (front edges) 521 and 531 in the circumferential direction. In other words, the upper surface 51 has two circumferential edges 521 and 531 at respective edges on the tire circumferential direction side.
- the upper surface 51 of the block 5 of the tread 1 can be measured by measuring the distance from the tire rotation axis to any point on the upper surface 51 in the region excluding the two front edges 521 and 531.
- the distance between the front edges 521 and 531 measured from the tire rotation axis is larger than the distance Re. More specifically, as shown in a cross section in FIG. 2, the upper surface 51 extends inward of the upper surface 51 from the front edges 521 and 531 in the tire circumferential direction, and the radial distance from the tire rotation axis gradually increases. It has two parts 511 which increase, and an intermediate part 512 sandwiched between parts 511 where the radial distance increases gradually.
- the intermediate portion 512 is formed in a curved shape having substantially the same radius as that of the tire.
- the intermediate portion 512 is always in contact with the road surface regardless of the road surface condition, but this varies depending on the load condition and the like.
- a part of the two portions 511 whose radial distance gradually increases always contacts the road surface.
- the front edges 521 and 531 are formed so as to come into contact with the road surface under specific road surface conditions.
- the front side walls 52 and 53 provided with the reinforcing portion 7 are positioned on the outermost position of the reinforcing portion 7 measured in the radial direction (the outer edge of the reinforcing portion 7 in the radial direction) and the front edge.
- the distance between 521 and 531 is 2.0 mm or less.
- the reinforcing portion 7 is preferably formed so as to at least partially include the front edges 521 and 531, and more preferably include all the front edges 521 and 531. In the example shown in FIG.
- the distance between the radially outermost position of the reinforcing portion 7 and the positions of the front edges 521 and 531 is zero (0 mm), and the reinforcement provided on the front side walls 52 and 53 is provided.
- the outermost edge in the radial direction of the portion 7 is provided so as to exist over the entire width direction of the front edges 521 and 531.
- the outermost edge in the radial direction of the reinforcing portion 7 provided on the front side walls 52 and 53 is provided so as to exist at least partially on the front edges 521 and 531 in the width direction of the front edges 521 and 531. May be.
- the reinforcing portion 7 is provided only in a partial region of the front side walls 52 and 53, but in order to maximize the effect of the reinforcing portion 7, the entire region of the front side walls 52 and 53 is provided. It is preferable to be provided over. Naturally, such a reinforcing portion 7 is provided so as to include all the front edge portions 521 and 531 as in the present embodiment.
- the difference G from the distance Re is up to 0.2 mm or more and 2.0 mm or less when the tread 1 is new. In the example shown in FIG. 2, this “difference G” is 0.5 mm.
- FIG. 2 in a cross-sectional view perpendicular to the tire rotation axis, a straight line connecting the two front edges 521 and 531 and a tangent line of the upper surface 51 passing through each front edge 521 and 531. Angles A are formed between them, and these angles A are formed to be 20 degrees or more.
- the front edge portions 521 and 531 are brought into contact with the road surface, while the friction on the road surface is on ice.
- the front edge portions 521 and 531 can be prevented from coming into contact with the road surface.
- the angle A described above is 28 degrees.
- the angle A is preferably 60 degrees or less.
- the block 5 is designed to prevent the block from being deformed even when traveling on a road surface where the friction coefficient of the road surface is insufficient to deform the grounding element as on ice. At least one is formed so that the average distance between the two front edges 521 and 531 measured in the tire circumferential direction is 15 mm or more. Thereby, generation
- the reinforcing portion 7 is provided so as to face the main groove 3 and / or the sub-groove 4 over a region of 60% or more of the front side walls 52 and 53, and the elasticity of the material forming the reinforcing portion 7.
- the rate Ef at least 20 times higher than the elastic modulus Et of the rubber composition forming the tread 1, when running on a road surface where the coefficient of friction of the road surface is sufficiently high to deform the block 5 as on snow, the reinforcing part Due to the effect of 7, a high front edge pressure can be obtained locally.
- one front edge 521 (or 531) is grounded mainly during acceleration or normal travel, and the other front edge 531 (or 521) is grounded mainly during deceleration. That is, in the tread of this embodiment, when the road surface condition is such, one of the two portions 511 where the radial distance of the upper surface 51 gradually increases is grounded. Therefore, according to the tread of this embodiment, it becomes possible to make the front edges 521 and 531 of the block 5 dig into the snow more, thereby improving the performance on snow.
- the average thickness of the reinforcing layer 7 is 0.1 mm or more and 2.0 mm or less, when traveling on a road surface where the friction coefficient of the road surface is insufficient to deform the block 5 as on ice, It is possible to prevent the front edge portions 521 and 531 from coming into contact with the road surface. That is, in the tread according to the present embodiment, in such a road surface condition, the vicinity of the front edges 52 and 53 on the upper surface 51 (for example, the two portions 511 in which the radial distance is gradually increased) is not grounded. It has become. As a result, it is possible to prevent the formation of a water film that is well known as one of the causes for reducing the friction coefficient on ice, and the tread of this embodiment. According to this, the performance on ice can be improved.
- the material of the reinforcing portion 7 in addition to the above-mentioned materials based on natural resins (including rubber materials), materials based on natural resins are mixed or impregnated with fibers, thermoplastic resins, and those Can also be used in combination with woven or non-woven fabric impregnated with a material based on natural resin for the purpose of improving the adhesion to the block 5 or for further reinforcement. You can also A fiber material such as a woven fabric or a nonwoven fabric impregnated with a material based on a natural resin may be used alone as the reinforcing portion 7.
- the reinforcing portion 7 may be provided on either one of the two front side walls 52 and 53.
- the bottom surface of the sub-groove 4 is not covered with the reinforcing portion 7, but the inner edge of the reinforcing portion 7 in the tire radial direction is used for the purpose of improving productivity when the reinforcing portion 7 is provided.
- You may comprise so that the part may be extended and the reinforcement part 7 may cover a part or all of the bottom face of the groove
- the reinforcing portion 7 is provided only on the front side walls 52 and 53 of the block facing the sub-groove 4, but the reinforcing portion 7 is similarly the side wall of the block facing the circumferential main groove 3. (Side side walls) 54 and 55 can also be provided. As a result, it is possible to mainly improve the on-snow performance effect in the tire width direction by the reinforcing portion 7, and in particular to improve the steering performance.
- the shape of the upper surface 51 of the block 5 is not limited to the shapes shown in FIGS. 1 and 2 of the present embodiment, and FIGS. 3 and 4 of the second and third embodiments described later, but as described above.
- the distance from the tire rotation axis in the entire area of the block upper surface 51 excluding the front edges 521 and 531 is larger than the distance from the tire rotation axis of the front edges 521 and 531 and the above-mentioned conditions such as the distance Re and the difference G
- the upper surface 51 may be formed in a curved shape having a predetermined curvature as a whole or in a triangular shape as a whole in a cross-sectional view perpendicular to the tire rotation axis. .
- FIG. 3 is an enlarged cross-sectional view schematically showing a block of a pneumatic tire tread according to a second embodiment of the present invention.
- the tread 1 has a ground contact surface 2 that comes into contact with the road surface during tire rolling, as in the first embodiment, and includes two circumferential main grooves 3.
- a plurality of sub-grooves 4 are formed.
- a plurality of blocks 5 are defined by these circumferential main grooves and sub-grooves.
- the block 5 includes an upper surface 51 that forms part of the ground contact surface 2, two side walls (front side walls) 52 and 53 that are spaced apart in the longitudinal direction corresponding to the tire circumferential direction, and a lateral direction that corresponds to the tire axial direction. It has two side walls (side wall) 54 and 55 which are spaced apart.
- the upper surface 51 intersects with the front side walls 52 and 53 and forms front edges 521 and 531.
- the block 5 is formed with a thin notch 6 that opens in the upper surface 51 and extends in the tire width direction and extends in the tire radial direction (or may be substantially in the radial direction).
- the reinforcing portions 7 are provided on the two front side walls 52 and 53.
- each reinforcing portion 7 has an average thickness t of less than 2.0 mm, preferably 1.0 mm so as to face the secondary groove 4 over a region of 60% or more, preferably 75% or more of the front side walls 52 and 53. It is provided to be less than mm.
- the front side walls 52 and 53 provided with the reinforcing portion 7 are provided so that the distance between the outermost position of the reinforcing portion 7 measured in the radial direction and the front edges 521 and 531 is 2.0 mm or less. Yes. In the example shown in FIG.
- the reinforcing part 7 is provided over 90% of the front side wall parts 52, 53, the average thickness t is 0.5 mm, and the outermost part of the reinforcing part 7 measured in the radial direction The distance between the front edge portions 521 and 531 is 1.0 mm.
- Front edge portions 521 and 531 are formed on the upper surface 51 as in the first embodiment described above.
- two chamfered portions 56 extending from the front edge portions 521 and 531 are formed on the upper surface 51.
- these chamfered portions 56 form an edge 561 different from the front edge portions 521 and 531 on the upper surface 51, but the edge 56 formed by the chamfered portion 56 is a front edge.
- the edge is always in contact with the road surface regardless of the road surface condition.
- the intermediate region 512 between the edges 56 on the flat surface 51 is always in contact with the road surface regardless of the road surface condition.
- the difference G between the distance Rt from the rotation axis to the outermost surface of the upper surface of the block 5 and the distance Re to the two front edges 521 and 531 similarly measured from the rotation axis is the tread. 1 is 0.2 mm or more and 2.0 mm or less at the time of a new article, and is measured from an axis of rotation, and arbitrary points excluding the front edge parts 521 and 531 on the upper surface 51 (the entire area of the upper surface 51 excluding the front edge parts 521 and 531 Is formed so that the distance to any point) is larger than Re. In the example shown in FIG. 3, the difference G is 0.5 mm.
- an angle A is created between a straight line connecting the two front edges 521 and 531 and a tangent line of the upper surface 51 passing through the front edges 521 and 531. Is formed to be 20 degrees or more.
- the tangent line of the upper surface 51 passing through the front edges 521 and 531 is a straight line of the chamfered portion 56, and the forming angle of the chamfered portion 56 is substantially the angle A described above.
- the front edges 521 and 531 contact the front edge portions 521 and 531 with the road surface when traveling on a road surface whose friction coefficient is sufficiently high to deform the block, such as on snow.
- the front edges 521 and 531 can be prevented from coming into contact with the road surface.
- the angle A described above is 45 degrees.
- the reinforcing portion 7 does not include the front edge portions 521 and 531, that is, the reinforcing portion 7 is not provided so as to extend to the front edge portions 521 and 531.
- the reinforcing portion 7 when traveling on a road surface having a friction coefficient that is sufficiently high to deform the block 5, locally high edge pressure can be obtained at the front edge portions 521 and 531 of the block 5 due to the effect of the reinforcing portion 7. And can effectively improve performance on snow.
- the chamfered portion 56 extending from the front edges 521 and 531 is formed on the upper surface 51 of the block 5, when traveling on a road surface where the friction coefficient of the road surface is insufficient to deform the block 5 as on ice.
- a water film generated between the tread and ice which is well known as one of the causes for reducing the coefficient of friction on ice by more reliably preventing the front edge portions 521 and 531 from contacting the road surface. Can be prevented, thereby improving the performance on ice.
- the side wall portion formed by the thin notch 6 and the front side walls 51 and 52 with or without the reinforcing portion 7 provided on the side wall portion formed by the thin notch 6 provided in the block 5 Or a plurality of thin cuts 6, the distances Rt, Re and the difference between the side wall part formed by the thin cuts 6 and the side wall part formed by the other thin cuts 6.
- the relationship with G may be satisfied.
- FIG. 4 is an enlarged cross-sectional view schematically showing a block of a tread for a pneumatic tire according to a third embodiment of the present invention.
- the tread 1 of the third embodiment has a ground contact surface 2 that comes into contact with the road surface when the tire rolls, as in the first embodiment described above, and includes two circumferential main grooves 3.
- a plurality of sub-grooves 4 are formed.
- a plurality of blocks 5 are defined by these circumferential main grooves and sub-grooves.
- the block 5 includes an upper surface 51 that forms a part of the ground contact surface 2, two side walls (front side walls) 52 and 53 that are positioned in the vertical direction corresponding to the tire circumferential direction, and a horizontal direction that corresponds to the tire axial direction. Have two side walls (side walls) 54 and 55 respectively.
- the upper surface 51 intersects with the front side walls 52 and 53 and forms front edges 521 and 531.
- the reinforcing portions 7 are provided on the two front side walls 52 and 53.
- each reinforcing portion 7 has an average thickness t of less than 2.0 mm, preferably so as to face the sub-groove 4 over a region of 60% or more, preferably 75% or more of the front side walls 52, 53. It is provided to be less than 1.0mm.
- Each reinforcing portion 7 is provided so that the distance between the outermost position of the reinforcing portion 7 measured in the radial direction and the front edges 521 and 531 is 2.0 mm or less. In the example shown in FIG. 4, the reinforcing portion 7 is provided over the entire area of the front side walls 52 and 53 and is formed so as to include all the front edges.
- the average thickness t is 1.0 mm, and is measured in the radial direction. The distance between the outermost position of the reinforcing portion 7 and the front edges 521 and 531 is zero (0 mm).
- two chamfered portions 56 extending from the front edges 521 and 531 are formed on the upper surface 51. Due to the chamfered portion 56, an edge 561 different from the front edge portions 521 and 531 is formed on the upper surface 51, but the edge 56 formed by the chamfered portion 56 is different from the front edge portions 521 and 531. Unlike the road surface condition, the edge is always in contact with the road surface. The intermediate region 512 between the edges 56 on the flat surface 51 is always in contact with the road surface regardless of the road surface condition.
- the difference G between the distance Rt to the outermost side of the upper surface 51 of the block 5 measured from the rotation axis and the distance Re to the two front edges 521 and 531 similarly measured from the rotation axis is:
- the tread 1 is 0.2 mm or more and 2.0 mm or less when new, and is formed such that the distance from the rotation axis to any point on the upper surface 51 excluding the front edge portions 521 and 531 is larger than Re.
- the difference G is 0.5 mm.
- an angle A is created between a straight line connecting the two front edges 521 and 531 and a tangent line of the upper surface 51 passing through the front edge. It is formed to be more than the degree.
- the tangent line of the upper surface 51 that passes through the front edge portion is the formation angle of the chamfered portion 56, and in this embodiment, the formation angle of the chamfered portion 56 is substantially the angle A described above.
- the reinforcing portion 7 has an average thickness t of 1.0 mm, includes all of the front edge portions 521 and 531, and is provided over the entire area of the front side walls 52 and 53.
- t average thickness
- the reinforcing portion 7 When traveling on a road surface with a coefficient of friction of the road surface that is sufficiently high to deform the block 5, a higher edge pressure can be obtained locally at the front edges 521 and 531 of the block 5 due to the effect of the reinforcing portion 7, The performance on snow can be improved effectively.
- the chamfered portion 56 is provided, the front edge portions 521 and 531 are prevented from coming into contact with the road surface when traveling on a road surface where the coefficient of friction of the road surface is insufficient to deform the block 5 as on ice. Thus, it is possible to prevent the formation of a water film generated between the tread and ice, thereby improving the performance on ice.
- FIG. 5 is an enlarged cross-sectional view schematically showing a conventional tread block for a pneumatic tire.
- the block 15 of this conventional pneumatic tire tread has an upper surface 151 that constitutes a part of the ground contact surface 12, and forms front edges 1521, 1531 at intersections with the front side walls 152, 153.
- the block 15 is formed with a thin notch 16 that opens in the upper surface 151 and extends in the lateral direction and the inner radial direction of the tire.
- the two front side walls 152 and 153 are provided with a reinforcing portion 17 so as to include all the front edges 1521 and 1531.
- the average thickness t of the reinforcing portion 17 is 0.5 mm, and the reinforcing portion 17 is provided so as to face the sub-groove 14 over an area of 84% of the front side walls 152 and 153.
- the distance Rt from the rotation axis to the outermost portion of the upper surface of the block 15 is the same as the distance Re from the rotation axis to the two front edges 1521, 1531, and the distance from the rotation axis to the upper surface 151 is the same.
- the distance to any point is also equal to Rt and Re.
- Examples 1 to 3 are block models provided with a reinforcing portion according to the first embodiment.
- the distance from the tire rotation axis to the outermost part of the upper surface of the block is also measured from the tire rotation axis.
- the difference G from the distance to the two front edges is three different values.
- Examples 4 to 6 are block models provided with a reinforcing portion according to the second embodiment. Similarly, the distance from the tire rotation axis to the outermost part of the upper surface of the block, and the tire rotation axis
- the difference G from the distance to the two front edge portions measured is set to three different values.
- each of the six types of block models according to the conventional example and the example is 10 mm in short side length, 20 mm long side length, and 10 mm height made of the same rubber material (elastic modulus 5.4 MPa). A cube was formed, and the thin notches were each 0.4 mm wide and 7 mm deep opening on the upper surface of the block.
- the reinforcing part is also made of the same material (elastic modulus 270 MPa) so that the elastic modulus of the reinforcing part material is 50 times the elastic modulus of the rubber material of the block.
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Abstract
Description
例えば、特許文献1(主に図3)には、3本の細い切れ込みと1本の副溝が設けられたブロックの、横溝及び副横溝に面したブロックの側壁に、JIS A硬度が80から95度のゴムを用いた補強部を設けることにより、雪上性能と氷上性能を両立するようにした空気入りタイヤが記載されている。
また、「主溝」とは、流体の排水を主に受け持つ、トレッドに形成される種々の溝の中で比較的広い幅を持つ溝のことを言う。主溝は、多くの場合、直線状、ジグザグ状又は波状にタイヤ周方向に延びる溝を意味するが、タイヤ回転方向に対して角度を持って延びる、流体の排水を主に受け持つ比較的広い幅を持つ溝も含まれる。
また、「主溝」以外の溝を「副溝」と呼ぶ。
ここで、υはポアソン比であり、ゴム材料のポアソン比は0.5に非常に近い値となる。
このように構成された本発明においては、雪上において、補強部の効果により、正面エッジによる局所的に高いエッジ圧力を確実に得ることが出来、その結果、氷上性能の向上を図りながら、より雪上性能を向上させることが出来る。
このように構成された本発明においては、より確実に、正面エッジによる局所的に高いエッジ圧力を確実に得ることが出来る。
このように構成された本発明においては、雪上において、正面エッジによる局所的に高いエッジ圧力をより確実に得ることが出来、その結果、氷上性能の向上を図りながら、より雪上性能を向上させることが出来る。
このように構成された本発明においては、雪上において加速時、減速時共に、ブロック上面と、補強部が設けられた正面側壁との交差部に形成された正面エッジによる局所的に高いエッジ圧力を得ることができ、その結果、氷上性能の向上を図りながら、より雪上性能を向上させることが出来る。
このように構成された本発明においては、氷上のように路面の摩擦係数が接地要素を変形させるのに不十分な路面を走行する際、正面エッジが路面に接触する事を防ぎつつ、接地面としてのブロックの上面の一部と路面との接触を十分に確保する事ができ、その結果、より氷上性能を向上させることが出来る。言い換えると、この角度を20度未満とすると、正面エッジが路面に接触する事を確実に防止できず、氷上性能を低下させる恐れがある。
このように構成された本発明においては、雪上において、ブロック上面と、補強部が設けられた正面側壁との交差部に形成された正面エッジによる局所的に高いエッジ圧力をより確実に得ることが出来、その結果、氷上性能の向上を図りつつ、より雪上性能を向上させることが出来る。
このように構成された本発明では、より確実に、氷上性能の向上を図りつつ、より雪上性能を向上させることが出来る。
このように構成された本発明においては、氷上のように路面の摩擦係数が接地要素を変形させるのに不十分な路面を走行する際であってもブロックが変形してしまう事を防止することが可能であり、これにより、トレッドと氷との間での水膜の発生を防止することが出来、その結果、より氷上性能を向上させることが出来る。
ここで、「細い切れ込み」とは、いわゆるサイプなどとも呼ばれる、ナイフの刃のようなものにより形成された切れ込みのことを言い、この細い切れ込みのトレッド表面での幅は、主に副溝に対して相対的に小さく、概ね2mm以下である。
このように構成された本発明においては、細い切れ込みは、補強部により全体的に高められたブロック剛性を部分的に低下させて、路面との密着性、特に氷上における路面との密着性を向上させることが出来、その結果、氷上性能を向上させることが出来る。同時に、細い切れ込みは、雪上のように路面の摩擦係数が接地要素を変形させるのに十分に高い路面を走行する際のブロックの変形を助ける事が出来、正面エッジによる局所的に高いエッジ圧力をさらに高めて、正面エッジ部を十分に雪に食い込ませることが可能となり、その結果、より雪上性能を向上させることが出来る。また、よく知られた現象として、細い切れ込みは、氷上における摩擦係数を低下させる原因の一つとしてよく知られている、トレッドと氷との間で発生した水膜を除去するための追加の貯蔵領域として作用する事が出来、その結果、より氷上性能を向上させることが出来る。
先ず、図1及至図2により、本発明の第1実施形態による空気入りタイヤ用トレッドを説明する。図1は、本発明の第1実施形態による空気入りタイヤ用トレッドを模式的に示す斜視図であり、図2は、図1のII-II線に沿って見た空気入りタイヤ用トレッドのブロックの拡大断面図である。
このトレッド1は、弾性率Etを有するゴム組成物から成り、タイヤ転動時に路面と接触する接地面2を有し、二本の周方向主溝3及び複数の副溝4が形成されている。これらの周方向主溝3及び副溝4により、複数のブロック5が区画形成されている。
このブロック5は、接地面2の一部を形成する上面51と、タイヤ周方向に沿った縦方向にてそれぞれ位置し、副溝4に面するように形成された二つの側壁(正面側壁)52,53と、タイヤ回転軸線方向に沿った横方向にそれぞれ位置し、周方向溝3に面するように形成された二つの側壁(側面側壁)54,55と、を有している。
本実施形態では、各補強部7は、正面側壁52,53の60%以上、好ましくは75%以上、より好ましくは全ての領域にわたって副溝4に面するように設けられる。また、各補強部7は、その平均厚さt(図2に示す)が2.0mm未満、好ましくは1.0mm未満となるように設けられる。ここで、補強部7の厚みは、補強部7が設けられている正面側壁52,53の副溝4に面した表面に垂直な方向の厚さであり、「平均厚さ」は、補強部7における、副溝4の底面側からブロック5の上面51側までの間で測定される平均値、即ち、補強部7のほぼ全面での平均値である。本実施形態においては、補強部7は正面側壁52,53の84%の領域にわたって設けられ、平均厚さtは0.5mmである。ここで、補強部7の平均厚さtは、0.2mm以上であることが好ましい。
上面51は、タイヤ転動時に路面と接触するトレッド1の接地面2の一部を形成し、この上面51は、特定の条件下で、その一部が路面と接触可能なブロック5の領域として定義される。上面51は、周方向において、二つの周方向エッジ(正面エッジ)521,531により制限されている。言い換えると、上面51は、そのタイヤ周方向側のそれぞれの縁部に二つの周方向エッジ521,531を有している。
本実施形態では、補強部7が設けられた正面側壁52,53は、半径方向に測定される補強部7の最外側の位置(補強部7の半径方向外方の縁部)と、正面エッジ521,531との間の距離が2.0mm以下となるように形成されている。この補強部7は、好ましくは、少なくとも部分的に正面エッジ521,531を含み、より好ましくは、正面エッジ521,531全てを含むように形成されている。図2に示す例では、補強部7の半径方向最外側の位置と正面エッジ521,531の位置との間の距離はゼロ(0mm)であり、且つ、正面側壁52,53に設けられた補強部7の半径方向の最外側の縁部が、正面エッジ521,531の幅方向全てにわたり存在するよう設けられている。一方、正面側壁52,53に設けられた補強部7の半径方向の最外側の縁部が、正面エッジ521,531の幅方向において少なくとも部分的に正面エッジ521,531に存在するよう設けられていても良い。
本実施形態では、タイヤ回転軸線より測定される、ブロック5の上面51の半径方向最外側の部分(位置)までの距離Rtと、同じくタイヤ回転軸線より測定される、二つの正面エッジ521,531までの距離Reとの差Gは、トレッド1が新品時0.2mm以上2.0mm以下であり、図2に示す例では、この「差G」は0.5mmである。
本実施形態においては、まず、補強部7は正面側壁52,53の60%以上の領域にわたって主溝3及び/又は副溝4に面するように設けられ、補強部7を形成する材料の弾性率Efをトレッド1を形成するゴム組成物の弾性率Etより少なくとも20倍高くすることにより、雪上のように路面の摩擦係数がブロック5を変形させるのに十分高い路面を走行する際、補強部7の効果により局所的に高い正面エッジ圧力を得ることが出来る。このとき、主に加速時や通常走行時には、一方の正面エッジ521(又は531)が接地し、主に減速時には、他方の正面エッジ531(又は521)が接地する。即ち、本実施形態のトレッドは、このような路面状況のとき、上述した上面51の半径方向距離が徐々に増大する2つの部分511は、いずれかが接地するようになっている。従って、本実施形態のトレッドによれば、ブロック5の正面エッジ521,531をより雪に食い込ませることが可能となり、これにより雪上性能を改善することが出来る。
補強部7の材料としては、上述した天然樹脂を基にした材料(ゴム材料を含む)の他に、天然樹脂を基にした材料に繊維を混合または含浸させたもの、熱可塑性樹脂、及びそれらを積層または混合したもの等も使用することができ、ブロック5との接着性の向上もしくは更なる補強を目的として更に天然樹脂を基にした材料に含浸させた織布、不織布等と組み合わせて使用することもできる。天然樹脂を基にした材料に含浸させた織布、不織布等の繊維材料は、単独で補強部7として使用しても構わない。
また、本実施形態においては副溝4の底面は補強部7によって覆われていないが、補強部7を設ける際の生産性の向上などを目的として、補強部7のタイヤ半径方向内方の縁部を延長して、補強部7が溝3、4の底面の一部又は全部を覆うように構成しても良い。
本実施形態では、補強部7は正面エッジ部521,531を含んでいない構成、即ち、補強部7が正面エッジ部521,531まで延びるよう設けられていないが、このような場合でも、雪上のように路面の摩擦係数がブロック5を変形させるのに十分高い路面を走行する際、補強部7の効果により、ブロック5の正面エッジ部521,531おいて局所的に高いエッジ圧力を得ることが出来、効果的に雪上性能を改善することが出来る。
本実施形態では、補強部7は、平均厚さtを1.0mmとし、正面エッジ部521,531全てを含み、かつ、正面側壁52,53の全領域にわたって設けられているため、雪上のように路面の摩擦係数がブロック5を変形させるのに十分高い路面を走行する際、補強部7の効果により、ブロック5の正面エッジ521,531おいて局所的により高いエッジ圧力を得ることが出来、より効果的に雪上性能を改善することが出来る。
また、面取り部56を設けているため、氷上のように路面の摩擦係数がブロック5を変形させるのに不十分な路面を走行する際、正面エッジ部521,531が路面と接触することを防止して、トレッドと氷との間で発生した水膜の発生を防止することが可能となり、これにより氷上性能を向上することが出来る。
従来例および実施例に係る6種類のブロックモデルのサイズは、いずれも、同一のゴム系材料(弾性率5.4MPa)で形成された短辺長さ10mm、長辺長さ20mm、高さ10mmの立方体とし、細い切れ込みを、それぞれ、ブロックの上面に開口する幅0.4mm、深さ7mmとした。補強部に関しても、同一の材料(弾性率270MPa)にて形成されており、補強部の材料の弾性率が、ブロックのゴム系材料の弾性率の50倍となるようにした。
2 接地面
3 周方向主溝
4 副溝
5 ブロック
51 ブロックの上面(その一部が接地面2を含む)
52,53 周方向側の側壁、正面側壁
521,531 正面エッジ
54,55 タイヤ幅方向側の側壁、側面側壁
56 面取り部
6 細い切れ込み(サイプ)
7 補強部
Claims (11)
- 少なくとも1つのゴム組成物により形成された空気入りタイヤ用トレッドであって、
前記少なくとも1つのゴム組成物は規格ASTM D882-09に規定された引張試験から算出される弾性率Etを有し、
前記トレッドは、少なくとも1本の周方向主溝と、複数の副溝と、これらの周方向主溝及び副溝によって区切られた複数のブロックと、を有し、
前記複数のブロックのうち少なくとも1つのブロックは、その一部がタイヤ転動時に路面と接触する接地面となる上面と、タイヤ周方向に沿ってそれぞれ位置する2つの正面側壁と、タイヤ軸線方向に沿ってそれぞれ位置する2つの側面側壁と、を有し、
前記ブロックの上面は、前記2つの正面側壁と交差する位置に形成された2つの正面エッジを有し、
前記ブロックは、前記2つの正面側壁のうち少なくとも1つの正面側壁に設けられた補強部を有し、この補強部は、前記トレッドを形成するゴム組成物の弾性率Etより少なくとも20倍高い弾性率Efを有する材料により形成され、且つ、0.1mm以上2.0mm以下の平均厚さを有し、さらに、前記正面側壁の60%以上の領域にわたって少なくとも副溝に面するように設けられ、
前記ブロックの上面は、タイヤ回転軸線の方向から視たとき、前記2つの正面エッジを除いた領域において、タイヤ回転軸線から前記上面のいずれの点までの距離を測定しても、その距離が、タイヤ回転軸線から測定した前記2つの正面エッジまでの距離Reより大きくなるよう形成されると共に、タイヤ回転軸線から前記上面における最も半径方向外側の位置まで測定される距離Rtと、タイヤ回転軸線から前記2つの正面エッジまで測定される距離Reとの差Gが新品時0.2mm以上2.0mm以下であり、且つ、前記補強部の最も半径方向外側の位置と前記正面エッジとの間の距離が2.0mm以下であることを特徴とする空気入りタイヤ用トレッド。 - 前記ブロックの正面側壁に設けられた補強部は、前記正面エッジにおいて、正面エッジの幅方向の少なくとも一部に延びるよう設けられている請求項1に記載の空気入りタイヤ用トレッド。
- 前記ブロックの正面側壁に設けられた補強部は、前記正面エッジにおいて、正面エッジの幅方向全てにわたり延びるよう設けられている請求項2に記載の空気入りタイヤ用トレッド。
- 前記ブロックの上面における前記差Gが1.5mm以下である請求項1乃至3の何れか1項に記載の空気入りタイヤ用トレッド。
- 前記ブロックの正面側壁に設けられた補強部は、前記ブロックの2つの正面側壁の両方に設けられている請求項1及至4の何れか1項に記載の空気入りタイヤ用トレッド。
- 前記ブロックの上面は、タイヤ回転軸線の方向から視たとき、2つの正面エッジを結ぶ直線と、正面エッジを通る前記上面の接線との角度が20度以上である請求項1及至5の何れか1項に記載の空気入りタイヤ用トレッド。
- 前記ブロックの正面側壁に設けられた補強部が前記正面側壁の75%以上の領域にわたって設けられている請求項1及至6の何れか1項に記載の空気入りタイヤ用トレッド。
- 前記ブロックの正面側壁に設けられた補強部が前記正面側壁の全領域にわたって設けられている請求項7に記載の空気入りタイヤ用トレッド。
- 前記ブロックは、前記2つの正面エッジ間のタイヤ周方向の平均距離が15mm以上であるように形成されている請求項1及至8の何れか1項に記載の空気入りタイヤ用トレッド。
- 前記ブロックは、更に、前記上面に開口し、そのブロックの内方に延びると共にタイヤ幅方向に延びる細い切れ込みを有する請求項1及至9の何れか1項に記載の空気入りタイヤ用トレッド。
- 請求項1及至10の何れか1項に記載のトレッドを有する空気入りタイヤ。
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JP2014534435A JP6206731B2 (ja) | 2012-09-07 | 2013-09-09 | 空気入りタイヤ用トレッド及びこのトレッドを有する空気入りタイヤ |
EP13835177.0A EP2894050B1 (en) | 2012-09-07 | 2013-09-09 | Pneumatic tire tread and pneumatic tire with said tread |
KR1020157008618A KR20150052866A (ko) | 2012-09-07 | 2013-09-09 | 공압식 타이어 트레드 및 상기 트레드를 갖는 공압식 타이어 |
CN201380056771.6A CN104755279B (zh) | 2012-09-07 | 2013-09-09 | 充气轮胎胎面和具有所述胎面的充气轮胎 |
RU2015112585A RU2630043C2 (ru) | 2012-09-07 | 2013-09-09 | Протектор пневматической шины и пневматическая шина с таким протектором |
CA2882574A CA2882574C (en) | 2012-09-07 | 2013-09-09 | Pneumatic tire tread and pneumatic tire with said tread |
US14/426,589 US20150239296A1 (en) | 2012-09-07 | 2013-09-09 | Pneumatic tire tread and pneumatic tire with said tread |
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KR (1) | KR20150052866A (ja) |
CN (1) | CN104755279B (ja) |
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CN110740882A (zh) * | 2017-06-12 | 2020-01-31 | 倍耐力轮胎股份公司 | 用于车辆车轮的轮胎 |
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FR3014750B1 (fr) * | 2013-12-17 | 2017-02-24 | Michelin & Cie | Bande de roulement comprenant des pavés et de fines rainures sur les pavés |
JP6164236B2 (ja) * | 2015-02-26 | 2017-07-19 | 横浜ゴム株式会社 | 空気入りラジアルタイヤ |
FR3045469B1 (fr) * | 2015-12-16 | 2017-12-22 | Michelin & Cie | Pneumatique presentant des proprietes d'usure et de resistance au roulement ameliorees |
WO2018002488A1 (fr) * | 2016-06-30 | 2018-01-04 | Compagnie Generale Des Etablissements Michelin | Pneumatique avec une bande de roulement comportant des éléments de renforcement |
FR3059943A1 (fr) * | 2016-12-13 | 2018-06-15 | Compagnie Generale Des Etablissements Michelin | Pneumatique avec une bande de roulement comportant des elements de renforcement |
CN110770036A (zh) | 2017-05-31 | 2020-02-07 | 米其林集团总公司 | 包括胎面的轮胎 |
US11167595B2 (en) * | 2017-11-10 | 2021-11-09 | Paccar Inc | Tire tread with reduced rolling resistance |
CN108573085B (zh) * | 2018-02-07 | 2021-07-09 | 哈尔滨工业大学 | 一种快速生成轮胎花纹法向刚度云图的方法 |
FR3090659A3 (fr) * | 2018-12-21 | 2020-06-26 | Michelin & Cie | Bande de roulement pour pneumatique |
JP7473772B2 (ja) * | 2019-07-30 | 2024-04-24 | 横浜ゴム株式会社 | 空気入りタイヤ |
EP4065389B1 (en) * | 2019-11-27 | 2023-08-16 | Compagnie Generale Des Etablissements Michelin | A tread for improving snow performance |
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EP2894050B1 (en) | 2017-08-02 |
RU2630043C2 (ru) | 2017-09-05 |
RU2015112585A (ru) | 2016-11-10 |
US20150239296A1 (en) | 2015-08-27 |
CN104755279A (zh) | 2015-07-01 |
CA2882574A1 (en) | 2014-03-13 |
CN104755279B (zh) | 2016-12-28 |
KR20150052866A (ko) | 2015-05-14 |
EP2894050A4 (en) | 2016-04-20 |
EP2894050A1 (en) | 2015-07-15 |
CA2882574C (en) | 2020-03-31 |
JP6206731B2 (ja) | 2017-10-04 |
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