WO2015156397A1 - タイヤ用トレッド及びタイヤ - Google Patents
タイヤ用トレッド及びタイヤ Download PDFInfo
- Publication number
- WO2015156397A1 WO2015156397A1 PCT/JP2015/061279 JP2015061279W WO2015156397A1 WO 2015156397 A1 WO2015156397 A1 WO 2015156397A1 JP 2015061279 W JP2015061279 W JP 2015061279W WO 2015156397 A1 WO2015156397 A1 WO 2015156397A1
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- WO
- WIPO (PCT)
- Prior art keywords
- tire
- block
- radial direction
- side wall
- tread
- Prior art date
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Classifications
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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
- 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
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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
- 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
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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
- B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
-
- 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
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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
- B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
- B60C11/03—Tread patterns
- B60C11/0306—Patterns comprising block rows or discontinuous ribs
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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
- 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
- B60C11/1315—Tread patterns characterised by the groove cross-section, e.g. for buttressing or preventing stone-trapping with special features of the groove walls having variable inclination angles, e.g. warped groove walls
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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
- 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
- B60C11/1323—Tread patterns characterised by the groove cross-section, e.g. for buttressing or preventing stone-trapping with special features of the groove walls asymmetric
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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
- 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
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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
- 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
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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
- B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
- B60C11/03—Tread patterns
- B60C2011/0337—Tread patterns characterised by particular design features of the pattern
- B60C2011/0339—Grooves
- B60C2011/0341—Circumferential grooves
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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
- 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
- B60C11/1236—Tread patterns characterised by the use of narrow slits or incisions, e.g. sipes with special arrangements in the tread pattern
- B60C2011/1254—Tread patterns characterised by the use of narrow slits or incisions, e.g. sipes with special arrangements in the tread pattern with closed sipe, i.e. not extending to a groove
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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
- 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
- B60C2011/133—Tread patterns characterised by the groove cross-section, e.g. for buttressing or preventing stone-trapping with special features of the groove walls comprising recesses
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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
- 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
- B60C2011/1338—Tread patterns characterised by the groove cross-section, e.g. for buttressing or preventing stone-trapping with special features of the groove walls comprising protrusions
Definitions
- the present invention relates to a tire tread and a tire having the tread, and more particularly to a tire tread and a tire capable of improving performance on snow and performance on ice.
- 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 soft compounds compared to non-winter tires, with so-called edge effects and water film removal effects, as well as multiple narrow cuts that open to the contact surface. By doing so, the adhesion with the road surface in winter is improved.
- the mechanism that generates frictional force with the road surface in winter tires actually differs depending on whether the road surface is snow or ice. Therefore, even if a soft compound is used to improve the performance on ice when the road surface is ice, and a large number of thin notches are provided in the block as the grounding element, the block rigidity is reduced as a result, and the road surface is made of snow. It is known that the improvement of the performance on snow in the case will be hindered.
- Patent Document 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 higher.
- a tire that has both a performance on snow and a performance on ice by providing a reinforcing part using rubber having a brittle temperature of ⁇ 30 ° C. or less on the side wall of the block while having a composition blended by 50 parts by weight or more. are listed.
- Patent Document 3 a reinforcing layer (reinforcing portion) having a modulus (elastic modulus) of a material of 200 MPa or more is provided with a thickness of less than 0.5 mm over an area of 50% or more of the side wall of the block.
- a tread for a tire is described which has both performance on snow and performance on ice.
- Patent Document 4 As a means for improving the performance on snow, for example, in Patent Document 4 (see FIG. 4), there is a tire that improves the performance on snow by providing an undercut portion at the transverse edge of the block. Are listed.
- Patent Document 5 (see FIG. 1) describes a tire in which serrated irregularities are formed on a side wall surface of a block.
- the present invention has been made to solve the above-described problems of the prior art, and provides a tread for a tire capable of achieving both higher performance on snow and higher performance on ice, and a tire having the tread. For the purpose.
- the present invention is a tire tread formed of at least one rubber composition and having a contact surface in contact with a road surface when the tire rolls, wherein the at least one rubber composition is ASTM
- the tread has an elastic modulus Et obtained from a tensile test specified in D882-09, and the tread includes at least one circumferential main groove extending in the tire circumferential direction, a plurality of sub grooves extending in the tire rotation axis direction, and these
- Each of the plurality of blocks divided by the circumferential main groove and the sub-groove, and each of the plurality of blocks extends in the tire rotation axis direction and faces the sub-groove.
- the front surface of the block is formed at a position intersecting the front side wall and extending in the tire rotation axis direction. And a side edge formed in a position intersecting the side wall and extending in the tire circumferential direction, and the block has a reinforcing portion having an average thickness t provided on at least one front side wall of the side walls.
- the reinforcing portion has an elastic modulus Ef higher than the elastic modulus Et of the rubber composition forming the tread and the block, and at least one front side wall provided with the reinforcing portion has at least two raised portions and A corrugated portion having at least one valley is formed, and the corrugated portion constitutes at least a part of the front side wall and at least a part of the reinforcing part in at least one front side wall provided with the reinforcing part. It is characterized by being provided as follows.
- 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 takes charge of fluid drainage.
- the main groove means a groove that extends 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 referred to as “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.
- edges that define the upper surface of the block the intersection between the block upper surface and the front side wall on the tire rotation direction side is referred to as the “front edge”, and the intersection between the block upper surface and the side wall on the tire axial direction side is referred to as the “side surface”.
- front edge the intersection between the block upper surface and the side wall on the tire axial direction side is referred to as the “side surface”.
- side surface the intersection (each edge part of the side surface of a block) of the front side wall and side wall of a block.
- each edge of such a chamfer is interpreted as a side wall edge.
- the “thin cut” is a so-called sipe or the like, for example, a cut formed by a knife blade or the like.
- the width of the thin cut on the tread surface is mainly a transverse groove. Is relatively small (for example, 2.0 mm or less).
- elastic modulus means the tensile elastic modulus E calculated from the tensile test curve obtained from the tensile test specified in the standard ASTM D882-09. That is, the elastic modulus Et of the rubber composition and the elastic modulus Ef of the reinforcing portion are calculated from a tensile test curve obtained from a tensile test specified in the standard ASTM D882-09.
- the friction coefficient thereof is as on ice.
- the troughs of the wavy portions tend to deform the block. Therefore, it is possible to prevent the formation of a water film between the tread and ice, which is well known as one of the causes for reducing the friction coefficient on ice, and as a result, the performance on ice can be improved. I can do it.
- the wavy portion provided on at least one front side wall is reinforced by the reinforcing portion, when traveling on a road surface having a friction coefficient sufficiently large to deform the block, such as on snow.
- the reinforcing effect of the reinforcing portion can prevent excessive deformation of the block due to the trough portion of the wave-like portion, thereby obtaining a high edge pressure locally. Accordingly, it is possible to effectively cause at least one front edge to penetrate into the snow, and as a result, the performance on snow can be improved.
- the length Lr of the reinforcing portion of the block in the tire radial direction is preferably 80% or more and 100% or less of the block height h.
- the effect of improving the performance on snow by providing the reinforcing portion on at least one front side wall can be effectively exhibited even after the block is worn.
- an imaginary straight line extending along the upper surface of the block and passing through the front edge, a radially outermost raised portion of the wavy portion, and the raised portion
- the angle A viewed from the tire rotation axial direction between the virtual straight line connecting the valleys adjacent to each other in the tire radial direction is 60 ° or more and 90 ° or less.
- the angle A is 70 ° or more.
- the radially outermost portion of the corrugated portion is a raised portion and extends in parallel with the raised portion and the front edge.
- the corrugated portion has a predetermined width W and is formed over a predetermined distance D in the tire radial direction.
- the height h is 60% or more and 100% or less.
- the wavy portion is formed over a predetermined distance D of 60% or more and 100% or less of the height h of the block, so that such a portion provided on at least one front side wall is provided. With the effect of the wavy portion, it is possible to improve the performance on ice, and more effectively exert the effect of causing the front edge to dig into the snow effectively due to the effect of the reinforcing portion provided on at least one front side wall. .
- the predetermined distance D is the bulge that is the outermost portion in the tire radial direction when the portion that is the outermost portion in the tire radial direction is the raised portion and the portion that is the innermost portion in the tire radial direction is the raised portion. This is a distance measured in the tire radial direction between the portion and the raised portion which is the innermost side in the tire radial direction.
- the predetermined distance D means that, in the wavy portion, when the portion that becomes the outermost side in the tire radial direction is a raised portion and the portion that becomes the innermost side in the tire radial direction is a valley portion, the raised portion that becomes the outermost side in the tire radial direction And the distance measured in the tire radial direction between the innermost portion in the tire radial direction.
- At least one front side wall provided with the reinforcing portion has an offset amount dd between the raised portion and the valley portion in the wavy portion in the direction extending along the upper surface of the block and passing through the front edge. It is 0.2 mm or more and 3 mm or less. In the present invention configured as described above, when running on a road surface whose friction coefficient is small enough to deform the block, such as on ice, sufficient deformation of the block is ensured by the troughs of the wavy portions.
- the offset amount dd is smaller than 0.2 mm, the ground pressure in the vicinity of the front edge is increased when traveling on a road surface whose friction coefficient is insufficient to deform the block as on ice. Therefore, there is a risk of reducing the performance on ice. Also, if this offset amount dd is larger than 3 mm, when running on a road surface whose friction coefficient is sufficiently large to deform the block as on snow, it results from the troughs of the corrugated part due to the reinforcing effect of the reinforcing part. It becomes difficult to prevent excessive deformation of the block, and as a result, it becomes difficult to obtain a high edge pressure locally, which may reduce the performance on snow.
- the number of valleys in the wavy portion is 3 or less.
- both on-ice performance and on-snow performance can be achieved more effectively.
- the wavy portion has at least three raised portions and at least two valley portions, and the innermost portion in the tire radial direction of the wavy portion is a raised portion, which is a distance in the tire radial direction of the block.
- the smallest minimum distance Dmini between two ridges adjacent in the tire radial direction to each trough of the wavy part, and the largest maximum distance between two ridges adjacent to each trough in the wavy part in the tire radial direction The ratio (Dmaxi / Dmini) with Dmaxi is 1.0 or more and 1.3 or less.
- the wavy portion has at least two trough portions, the innermost portion in the tire radial direction of the wavy portion is a trough portion, and is the distance in the tire radial direction of the block.
- the smallest distance Dmini which is the smallest of the distances, and the distance between two ridges adjacent to each trough of the wavy portion in the tire radial direction or the trough that is the innermost portion in the tire radial direction in the wavy portion and this
- the ratio (Dmaxi / Dmini) to the largest maximum distance Dmaxi among the respective distances between the ridges adjacent to the valley in the tire radial direction is 1.0 or more and 1.3 or less.
- this ratio is greater than 1.3, the wavy portion tends to deform unevenly when a load is applied, resulting in a decrease in the durability of the wavy portion, and also the durability of the block. There is a risk of lowering.
- the block preferably has at least one narrow notch that opens at least on its upper surface and extends in the tire radial direction.
- the block rigidity which has been enhanced by the reinforcing portion as a whole, can be partially reduced by a thin notch, thereby improving the adhesion between the block and the road surface.
- the narrow notch can facilitate the deformation of the block when traveling on a road surface whose coefficient of friction is sufficiently large to deform the block, such as on snow.
- the locally high edge pressure by the front edge can be increased more effectively, and the front edge can be sufficiently absorbed into the snow.
- the performance on snow can be further improved.
- the narrow notch opens at least on the upper surface of the block, it functions as an additional space for removing the water film generated between the tread and ice, which is one of the causes for reducing the friction coefficient on ice. As a result, the performance on ice can be further improved.
- the reinforcing portion and the corrugated portion are provided on the two front side walls of the block.
- the performance improvement effect on the winter road surface described above is the most important acceleration for safety. It is possible to make it more reliable at times and during deceleration.
- the elastic modulus Ef of the material constituting the reinforcing portion is at least 20 times the elastic modulus Et of the rubber composition constituting the tread and the block.
- the elastic modulus Ef of the material constituting the reinforcing portion is 40 times or more the elastic modulus Et of the rubber composition constituting the tread and the block.
- the elastic modulus Ef of the material constituting the reinforcing portion is such that a high edge pressure is generated when traveling on a road surface whose friction coefficient is small enough to deform the block, such as on ice.
- the elastic modulus Et of the rubber composition constituting the tread and the block is 60 times or less.
- the average thickness t of the reinforcing portion is 0.1 mm or more and 2.0 mm or less.
- the ground pressure as the whole block can be made more uniform, and as a result, The performance on snow can be improved more reliably while maintaining the performance on ice.
- the average thickness t of the reinforcing portion is smaller than 0.1 mm, the reinforcing effect of the block by the reinforcing portion is relatively lowered.
- the reinforcement portion prevents excessive deformation of the block due to the corrugated valley. Effect may be reduced and performance on snow may be reduced.
- the average thickness t of the reinforcing portion is larger than 2.0 mm, the reinforcing effect of the block by the reinforcing portion is relatively increased. That is, when driving on a road surface whose friction coefficient is small enough to deform the block, such as on ice, the deformation of the block due to the trough of the corrugated portion is likely to occur due to the increased reinforcement effect of the reinforcing portion.
- a relatively large load is applied to the reinforcing portion and the ground pressure is locally increased, which may reduce the performance on ice.
- the reinforcement part is provided over the whole area
- the present invention configured as described above, when traveling on a road surface whose coefficient of friction is sufficiently large to deform the block, such as on snow, it is possible to more reliably generate a high edge pressure at the front edge. Thus, the front edge can be more surely bitten into the snow. As a result, the performance on snow can be further improved.
- the wavy portion includes at least a part of the front edge.
- the present invention configured as described above, when traveling on a road surface whose coefficient of friction is sufficiently large to deform the block, such as on snow, it is possible to more reliably generate a high edge pressure at the front edge. . Accordingly, the front edge can be more surely bitten into the snow, thereby improving the performance on snow.
- the undulating portion is provided over the entire region of at least one front side wall.
- the effect of improving the performance on ice by the corrugated portion can be exhibited until the end of wear of the tread while the effect of improving the performance on snow by the reinforcing portion is exhibited.
- the block further includes a side wall edge formed at a position where the at least one front side wall provided with the reinforcing portion and the side side wall intersect with each other, and the wavy portion is formed on the at least one front side wall. It is offset from the front edge and the side wall edge by at least 0.5 mm.
- the wavy portion is offset by at least 0.5 mm or more from the front edge and the side wall edge of at least one front side wall, the portion of the front side wall other than the portion where the wavy portion is formed, That is, a portion offset from the front edge and the side wall edge can be formed.
- this offset part (part other than the wave part) travels on a road surface whose friction coefficient is sufficiently large to deform the block like snow, the block is excessively deformed by the valley part of the wave part. It becomes an additional reinforcement part for preventing, and this can improve the performance on snow more reliably. If this offset amount is smaller than 0.5 mm, not only the effect of the additional reinforcing portion described above is diminished, but also the front side wall portion other than the portion where the wavy portion is formed becomes brittle against deformation, so the durability of the block May decrease.
- At least one of the side walls of the block further has a reinforcing portion and a corrugated portion.
- the above-described effect of improving the snow and snow performance by the reinforcing portion and the corrugated portion can be exhibited even in a situation where force is applied from the side of the block side surface, such as during turning.
- 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 tire tread according to a first embodiment of the present invention. It is an expanded sectional view of the block of the tread for tires seen along the II-II line of FIG. It is a perspective view which shows typically the tread for tires by 2nd Embodiment of this invention.
- FIG. 4 is an enlarged cross-sectional view of a tire tread block taken along line IV-IV in FIG. 3. It is a perspective view which shows typically the tread for tires by 3rd Embodiment of this invention. It is an expanded sectional view of the block of the tread for tires by a prior art.
- FIG. 1 is a perspective view schematically showing a tire tread according to a first embodiment of the present invention
- FIG. 2 is an enlarged cross-sectional view of the tire tread block taken along line II-II in FIG. It is.
- reference numeral 1 denotes a tire tread according to the first embodiment of the present invention.
- An example of the tire size of the tire to which the tire tread 1 is applied is 205 / 55R16.
- the tread 1 is formed of at least one rubber composition having an elastic modulus Et obtained from a tensile test defined in ASTM D882-09, and comes into contact with the road surface during tire rolling.
- a ground plane 2 is provided.
- the tread 1 is formed with two circumferential main grooves 3 extending in the tire circumferential direction and a plurality of sub-grooves 4 extending in the tire rotation axis direction.
- the tread 1 is formed with a plurality of blocks 5 partitioned by these circumferential main grooves 3 and sub-grooves 4.
- These blocks 5 include an upper surface 51 that is a part of the ground contact surface 2, two side walls (front side walls) 52 and 53 that extend in the tire rotation axis direction and face the sub-groove 4, and the tire circumferential direction And two side walls (side wall surfaces) 54 and 55 formed so as to face the circumferential main groove 3.
- two front edges 521 and 531 extending in the tire rotation axis direction are formed at positions intersecting the two front side walls 52 and 53. Further, two side edges 541 and 551 extending in the tire circumferential direction are formed on the upper surface 51 at positions intersecting with the two side walls 54 and 55. In the block 5, four side wall edges 561 are formed at positions where the front side walls 52, 53 and the side side walls 54, 55 intersect.
- the two front side walls 52 and 53 are provided with reinforcing portions 6 made of a material having an elastic modulus Ef higher than the elastic modulus Et of the rubber composition forming the tread 1.
- the elastic modulus Et of the rubber composition forming the tread 1 is 4.8 MPa.
- This elastic modulus Et is preferably 1.5 MPa or more and 15 MPa or less.
- the elastic modulus Ef of the material forming the reinforcing portion 6 is 120 MPa. Therefore, the elastic modulus Ef of the material forming the reinforcing portion 6 is formed to be 25 times higher than the elastic modulus Et of the rubber composition forming the tread 1.
- the elastic modulus Et of the rubber composition forming the tread 1 and the elastic modulus Ef of the material forming the reinforcing portion 6 are based on the tensile test curve obtained from the tensile test specified in the standard ASTM D882-09. It can be calculated.
- each reinforcement part 6 is each provided so that at least one part of each front side wall 52 and 53 may be comprised.
- each reinforcing portion 6 is provided so as to face the sub-groove 4 over an area of 70% or more of the entire area of each front side wall 52, 53.
- Each reinforcing portion 6 is provided so that its average thickness t (see FIG. 2) is 2.0 mm or less, preferably 1.0 mm or less.
- the thickness t of the reinforcing portion 6 is measured in a direction perpendicular to the surface of the front side walls 52 and 53 provided with the reinforcing portion 6 facing the sub-groove 4.
- the value of the “average thickness” of these reinforcing portions 6 is an average value measured between the bottom-side edge of the sub-groove 4 of the reinforcing portion 6 and the edge on the top surface 51 side of the block 5, that is, It is an average value over almost the entire surface of the reinforcing portion 6.
- the reinforcing portion 6 includes the front edges 521 and 531 and is provided so as to constitute a part 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 6 is preferably not less than 0.1 mm and not more than 2.0 mm, and more preferably not less than 0.2 mm and not more than 1.0 mm.
- the outermost edge in the tire radial direction of the reinforcing portion 6 provided on the front side walls 52 and 53 extends over the entire width direction of the front edges 521 and 531.
- the outermost edge in the tire radial direction of the reinforcing portion 6 may be provided so as to partially exist in the width direction of the front edges 521 and 531.
- the upper surface 51 of the block 5 of the tread 1 will be described.
- the upper surface 51 forms a part of the ground contact surface 2 of the tread 1 that comes into contact with the road surface during tire rolling, and the upper surface 51 is partly in contact with the road surface under specific conditions. It is defined as a possible block 5 region.
- the upper surface 51 is formed at a position intersecting the front side walls 52 and 53 and extends in the tire rotation axis direction. 551, and these front edges 521 and 531 and side edges 541 and 551 limit the area.
- each corrugated portion 7 constitutes at least a part of the front side walls 52 and 53 and is reinforced in the front side walls 52 and 53 provided with the reinforcing portion 6. It is provided so as to constitute at least a part of the portion 6.
- the outermost portion in the tire radial direction of the wavy portion 7 is a raised portion 72 that linearly extends in the tire rotation axis direction and has a width W (see FIG. 1).
- the raised portion 72 is provided with the reinforcing portion 6.
- the front side walls 52 and 53 are formed so as to extend in parallel with the front edges 521 and 531.
- the other raised portions 72 are also formed to extend in parallel and linearly, and the valley portions 71 are also formed to extend in parallel and linearly.
- Each wavy portion 7 has at least two raised portions 72 and at least one valley portion 71, and is configured such that the number of valley portions 71 is 3 or less.
- the wavy portion 7 has three raised portions 72 and two valley portions 71.
- the wavy portion 7 has a width W (see FIG. 1) extending in the tire rotation axis direction, and extends from the outermost bulge portion 72 in the tire radial direction to the bulge portion 72 in the tire radial direction innermost side.
- region formed over distance D (refer FIG. 2) in a tire radial direction is said.
- each corrugated portion 7 is the front edges 521, 531 of the front side walls 52, 53 of the block 5, and the intersections of the front side walls 52, 53 and the side side walls 54, 55. It is offset from the side wall edge 561 by at least 0.5 mm.
- the offset amount du from the front edges 521 and 531 of the wavy portion 7 is 1.0 mm
- the offset amounts dl and dr from the side wall edge 561 are both 1.25 mm.
- the length Lr of the reinforcing portion 6 in the tire radial direction is 80 which is the height h of the block 5 in a cross-sectional view perpendicular to the upper surface 51 and front edges 521 and 531 of the block. It is formed to be more than%.
- the height h of the block 5 is 10 mm
- the length Lr of the reinforcing portion 6 is 8 mm. Therefore, the length Lr of the reinforcing portion 6 is formed to be 80% of the height h of the block 5.
- the length Lr of the reinforcement part 6 is 100% of the height h of the block 5.
- FIG. The height h of this block is measured in the tire radial direction between the deepest portion in the tire radial direction of the auxiliary groove 4 facing the front side walls 52 and 53 and the upper surface 51 of the block 5.
- an angle A viewed from the tire rotation axial direction between the imaginary straight line connecting the valley 71 adjacent to the tire radial direction of the raised portion 72 is 60 ° or more and 90 ° or less, preferably 70 ° It is formed so as to be at least 90 °. In the present embodiment, the angle A is 75 °.
- the distance in the tire radial direction (the distance D shown in FIG.
- the distance D of the corrugated portion 7 is 100% of the height h of the block 5.
- the distance D between the radially outermost raised portion 72 and the radially innermost raised portion 72 is 8 mm. Accordingly, in the wavy portion 7, the distance D between the radially outermost raised portion 72 and the radially innermost raised portion 72 is 80% of the height h of the block 5. .
- the distance D is such that the outermost portion in the tire radial direction becomes the raised portion 72 and the innermost portion in the tire radial direction in the wavy portion 7 as in a second embodiment (see particularly FIG. 4) described later.
- the wavy portion 7 has a width W, and the tire radial direction from the outermost raised portion 72 in the tire radial direction to the innermost valley 71 in the tire radial direction) Is a portion of the region formed over the distance D (see FIG. 2).
- each wavy portion 7 has an offset amount dd between the raised portion 72 and the valley portion 71 in the direction extending along the upper surface 51 of the block 5 and passing through the front edges 521 and 531.
- this offset amount dd is 0.5 mm.
- the offset amount dd of the wavy portion 7 is preferably 0.2 mm or more and 3.0 mm or less.
- each wavy portion 7 has at least three raised portions 72 and at least two valley portions 71, and the innermost portion in the tire radial direction of the wavy portion 7 is the raised portion 72, and each wavy portion 7, which is a distance in the tire radial direction, which is a minimum distance between two raised portions 72 adjacent to the valley 71 in the tire radial direction (Dmini, for example, distance D1 or distance D2 shown in FIG. 2), and other valleys 71.
- the ratio (Dmaxi / Dmini) to the maximum distance (Dmaxi, for example, distance D1 or distance D2 shown in FIG. 2) between two ridges 72 adjacent to each other in the tire radial direction is 1.0 or more and 1.3 or less. Has been.
- the wavy portion 7 has three raised portions 72 and 22 valleys 71, and the innermost portion in the tire radial direction of the wavy portion 7 is the raised portion 72,
- the distance between the two raised portions 72 (distance D2 shown in FIG. 2) is equally 4 mm. Therefore, in this embodiment, the ratio (Dmaxi / Dmini) is formed to be 1.0.
- each wavy part 7 has at least 2 protruding part 72 and at least 2 trough part 71, and the tire radial direction in the wavy part 7
- the wavy portion 7 is adjacent to the trough portion 71 in the tire radial direction, which is the distance in the tire radial direction.
- a minimum distance or a maximum distance (Dmini or Dmaxi, for example, a distance D3 shown in FIG.
- the minimum distance Dmini and the maximum distance Dmaxi in the wavy portion 7 are at least 2 when the tire radial direction outermost portion is the raised portion 72 and the tire radial direction innermost portion is the raised portion 72. It is selected from one of a set of “distance between two raised portions 72 adjacent to the valley portion 71 in the tire radial direction”. For example, when four bulges 72 are formed and three valleys 71 are formed, the above-described minimum distance Dmini and maximum distance Dmaxi are adjacent to three sets of “valleys 71 in the tire radial direction. The distance between the two raised portions 72 is selected.
- the minimum distance Dmini and the maximum distance Dmaxi in the wavy portion 7 are at least one set when the tire radial direction outermost portion is the raised portion 72 and the tire radial direction innermost portion is the valley portion 71. "Distance between two raised portions 72 adjacent to the valley portion 71 in the tire radial direction” and a set of "the valley portion 71 which is the innermost portion in the tire radial direction in the wavy portion 7 and the tire diameter in the valley portion 71 The distance between the ridges 72 adjacent to each other in the direction is selected.
- the above-described minimum distance Dmini and maximum distance Dmaxi are Four sets of “the distance between two raised portions 72 adjacent to the valley 71 in the tire radial direction” and one set of “the valley 71 that is the innermost portion in the tire radial direction in the wavy portion 7 and the valley 71.
- the distance between the ridges 72 adjacent to each other in the tire radial direction is selected.
- the above-described tire tread 1 is particularly suitable for winter tires.
- the angle A is set to 90 degrees or less, a moment force acting geometrically in the direction of decreasing the edge pressure at the front edge portions 521 and 531 is generated in the wavy portion 7 of the block 5 under such conditions. To do.
- the tread 1 of the present embodiment it is possible to prevent the generation of a water film between the tread and ice, which is well known as one of the causes for reducing the friction coefficient on ice. As a result, the performance on ice can be improved.
- the portion 7 is provided on the front side walls 52 and 53, and the block 5 is easily deformed by the valley portion 71 of the wavy portion 7, the block 5 may be excessively deformed due to the reinforcing effect of the reinforcing portion 6. It is suppressed. Furthermore, since the wavy portion 7 is provided at least 0.5 mm or more offset from the front edges 521, 531 and the side wall edge 561 of the front side walls 52, 53, the front side walls 52, 53 other than the region where the wavy portion 7 is formed.
- the average thickness t of the reinforcing portion 6 is not less than 0.1 mm and not more than 2.0 mm, preferably not less than 0.2 mm and not more than 1.0 mm.
- the average thickness t of the reinforcing portion 6 may be different between the front side walls 52 and 53 of the same block 5.
- the reinforcing portion 6 provided in at least a part of the front side walls 52 and 53 may be provided in a different ratio of the front side walls 52 and 53 of the same block 5.
- the cross-sectional shapes of the raised portion 72 and the valley portion 71 in the cross-sectional view perpendicular to the upper surface 51 of the block and the front edges 521 and 531 in the wavy portion 7 are formed to have corners.
- it may be a polygonal shape or an arc shape, and may be configured such that these shapes are mixed in one wavy portion 7.
- the wavy portion 7 is provided in the front side walls 52 and 53 so as to constitute at least a part of the front side walls 52 and 53 and at least a part of the reinforcing portion 6.
- the front side walls 52 and 53 of the block 5 may be different from each other, or the front side walls 52 and 53 of the same block 5 may be provided in different ratio areas.
- the material of the reinforcing portion 6 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 In order to improve adhesion with the block 5 or to further reinforce, it can be used in combination with a woven fabric or nonwoven fabric impregnated with a material based on a natural resin. It can also be used. 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 6. Further, different materials may be used for the front side walls 52 and 53 of the same block 5.
- the reinforcing portion 6 is provided only on the front side walls 52 and 53 of the block facing the sub-groove 4, but the reinforcing portion 6 is similarly formed on the block facing the circumferential main groove 3. You may provide also in the side wall (side wall side) 54 and 55 (refer 3rd Embodiment of FIG. 5 mentioned later). As a result, it is possible to improve the effects of on-ice performance and on-snow performance especially in turning in the tire width direction by the reinforcing portion 6 provided on the side walls 54 and 55, and particularly to improve the steering performance.
- FIG. 3 is a perspective view schematically showing a tread for a tire according to a second embodiment of the present invention
- FIG. 4 is an enlarged cross-sectional view of a block of the tread for a tire taken along line IV-IV in FIG. It is.
- a configuration different from that of the first embodiment will be mainly described, and the description of the same configuration will be omitted.
- the tread 1 of the second embodiment includes a ground plane 2, two circumferential main grooves 3, a plurality of sub-grooves 4, and the like, as in the first embodiment described above. And a plurality of blocks 5 defined by the circumferential main grooves 3 and the sub-grooves 4. These blocks 5 have two front side walls 52 and 53 and two side side walls 54 and 55 as in the first embodiment.
- the upper surface 51 has front edges 521 and 531 at edges that intersect the front side walls 52 and 53, and side edges 541 and 551 at edges that intersect the side walls 54 and 55.
- four side wall edges 561 are formed at positions where the front side walls 52, 53 and the side side walls 54, 55 intersect.
- each reinforcement part 6 is provided so that it may comprise at least one part of the front side walls 52 and 53, Preferably, it is 70% or more of all the area
- Each reinforcing portion 6 is provided so that its average thickness t (shown in FIG. 4) is 2.0 mm or less, preferably 1.0 mm or less. In the example shown in FIG. 3, the reinforcing portion 6 is provided in the entire region of the front side walls 52 and 53, that is, in the region of 100%, and is provided so as to include all the front edges 521 and 531.
- the average thickness t is 0.5 mm.
- each corrugated part 7 forms at least a part of the front side walls 52 and 53 and at least a part of the reinforcing part 6 in the front side walls 52 and 53 provided with the reinforcing part 6. Preferably, it is provided over the whole area of the front side walls 52 and 53. Furthermore, each wave-like part 7 is provided so that at least one part of the front edges 521 and 531 may be included.
- the outermost portion in the tire radial direction of each wavy portion 7 is a raised portion 72 that linearly extends in the tire rotation axis direction and has a width W (see FIG. 3). The raised portion 72 is provided with the reinforcing portion 6.
- the front side walls 52 and 53 of the formed front edges 521 and 531 extend linearly at the same position and the same width W.
- Each wavy portion 7 has at least two raised portions 72 and at least one valley portion 71, and is configured such that the number of valley portions 71 is 3 or less.
- the corrugated portion 7 has two raised portions 72 and two trough portions 71, and the corrugated portion 7 is provided over the entire area of the front side walls 52 and 53, that is, 100% of the area.
- the wavy portion 7 includes all of the front edges 521 and 531.
- the offset amount dd between the raised portion 72 and the valley portion 71 in the direction extending along the upper surface 51 of the block 5 and passing through the front edges 521 and 531 is 3.0 mm or less. It is provided to become. In the present embodiment, this offset amount dd is 1.0 mm.
- the wavy portion 7 has at least two valley portions 71, and the outermost portion in the tire radial direction becomes the raised portion 72, and
- the minimum distance between the two raised portions 72 adjacent to the valley portion 71 in the tire radial direction is the distance in the tire radial direction of the block 5 in each wavy portion 7.
- Distance or maximum distance (Dmini or Dmaxi, for example, distance D3 shown in FIG.
- a ratio (Dmaxi / Dmini) to a minimum distance or a maximum distance (Dmini or Dmaxi, for example, distance D4 shown in FIG. 4) is 1.0 or more and 1.3 or less.
- the wavy portion 7 has two valleys 71, and a distance between two raised portions 72 adjacent to the valleys 71 on the tire radial direction outer side in the tire radial direction (see FIG. 4).
- the ratio (Dmaxi / Dmini) is formed to be 1.12.
- a thin notch 8 is formed in the block 5 of the tread 1 according to the second embodiment.
- the thin notch 8 is opened in the upper surface 51, extends in the tire width direction, and extends in the tire radial direction (including the case where the tire has an angle with respect to the tire radial direction within a range in which various functions of the thin notch 8 are exhibited). Yes.
- the thin cut 8 is not opened in the side walls 54 and 55, but may be opened in the side walls 54 and 55. As described above, the thin notch 8 may extend at a predetermined angle with respect to the tire radial direction within a range in which the 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 in the tire width direction at a predetermined angle. Reinforcing portions 6 are provided on the two front side walls 52 and 53.
- the width of the narrow notch 8 that opens to the upper surface 51 is 0.4 mm, and the depth in the tire radial direction is 8 mm.
- the length Lr of the reinforcing portion 6 in the tire radial direction is 80 which is the height h of the block 5 in a cross-sectional view perpendicular to the upper surface 51 and the front edges 521 and 531 of the block. It is formed to be more than%. In the present embodiment, since the reinforcing portion 6 is provided over the entire area of the front side walls 52 and 53 as described above, the length Lr of the reinforcing portion 6 is 100% of the height h of the block 5. Is formed.
- the height of the block 5 is the height of the block 5. It is formed to be 60% or more of h.
- the reinforcing portion 6 and the corrugated portion 7 are provided over the entire area of the front side walls 52 and 53.
- the reinforcing portion 6 can prevent buckling deformation of the wavy portion 7.
- the front edges 521 and 531 can be effectively sunk into the snow, and as a result, high performance on snow can be maintained for a long time.
- the bottom surface of the sub-groove 4 is not covered with the reinforcing portion 6, but for the purpose of improving the productivity of the tread 1 when the reinforcing portion 6 is provided, the inside of the reinforcing portion 6 in the tire radial direction is used.
- You may comprise so that the edge part of one side may be extended and the reinforcement part 6 may cover a part or all of the bottom face of the groove
- FIG. 5 is a perspective view schematically showing a tread for a tire according to a third embodiment of the present invention.
- the configuration different from the first and second embodiments described above will be mainly described, and the description of the same configuration will be omitted.
- the tread 1 of the third embodiment is similar to the first and second embodiments described above, in that the ground surface 2, the two circumferential main grooves 3, and the plurality of sub-grooves 4 A plurality of blocks 5 defined by the circumferential main grooves 3 and the sub-grooves 4 are provided. These blocks 5 have two front side walls 52 and 53 and two side wall sides 54 and 55 as in the first and second embodiments described above.
- the upper surface 51 has front edges 521 and 531 at edges that intersect the front side walls 52 and 53, and side edges 541 and 551 at edges that intersect the side walls 54 and 55.
- four side wall edges 561 are formed at positions where the front side walls 52, 53 and the side side walls 54, 55 intersect.
- each reinforcing portion 6 is provided so as to constitute at least a part of the front side walls 52 and 53 as in the first and second embodiments described above. Moreover, in this embodiment, each reinforcement part 6 is provided so that at least one part of the side wall 54,55 may be comprised.
- each corrugated part 7 forms at least a part of the front side walls 52 and 53 and at least a part of the reinforcing part 6 in the front side walls 52 and 53 provided with the reinforcing part 6. Furthermore, it is provided so that at least one part of the side wall 54,55 in which the reinforcement part 6 was provided may be comprised.
- the corrugated portions 7 provided on the side walls 54 and 55 are offset from the side edges 541 and 551 and the side wall edges 561 of the side walls 54 and 55 of the block 5 by at least 0.5 mm.
- the wavy portion 7 has two raised portions 72 and two valleys 71 on the front side walls 52 and 53, and three raised portions 72 and two on the side side walls 54 and 55. It has a valley 71. Further, the wavy portion 7 is provided so as to constitute the entire region of each reinforcing portion 6 in both the front side walls 52 and 53 and the side side walls 54 and 55.
- the reinforcing portion 6 and the corrugated portion 7 are further provided on the side walls 54 and 55 in addition to the front side walls 52 and 53.
- the shape of the corrugated portion 7 provided on the side side walls 54 and 55 may be different from that of the corrugated portion 7 provided on the front side walls 52 and 53.
- the shape and material of the reinforcing part 6 provided on the front side walls 52 and 53 may be different from the reinforcing part 6 provided on the front side walls 52 and 53.
- FIG. 6 is an enlarged cross-sectional view schematically showing a tread block according to the prior art.
- the block 105 of the tire tread 101 according to the prior art has an upper surface 151 that constitutes a part of the ground contact surface 102, and front edges 1521 and 1531 are formed at intersections between the upper surface 151 and the front side walls 152 and 153. Yes.
- the block 105 is formed with a thin notch 108 that opens in the upper surface 151 and extends in the lateral direction and the tire radial direction.
- the two front side walls 152 and 153 are provided with a reinforcing portion 106 so as to include all the front edges 1521 and 1531.
- the average thickness t of the reinforcing portion 106 is 0.5 mm, and the reinforcing portion 106 is provided so as to face the secondary groove 104 over the entire area of the front side walls 152 and 153.
- the corrugated portion is not provided on the front side walls 152 and 153 of the block 105.
- This example is a block model in which a reinforcing portion according to the second embodiment described above is provided.
- the size of the two types of block models according to the conventional example and the example used in the simulation are both made of the same rubber-based material (elastic modulus 5.4 MPa), with a short side length of 12 mm and a long side length.
- the cube was 15 mm in height and 10 mm in height, and the thin notches were set to have a width of 0.4 mm and a depth of 8 mm respectively opening on the upper surface of the block.
- the reinforcing part is also made of the same material (elastic modulus 270 MPa), and is provided over the entire area of the front side wall with an average thickness of 0.5 mm.
- the elastic modulus of the material of the reinforcing part is It was set to be 50 times the elastic modulus of the rubber material.
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Abstract
Description
例えば、特許文献1(図3参照)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において、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、流体の排水を主に担う、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、流体の排水を主に担う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」と言う。
また、ブロックの正面側壁と側面側壁との交差部(ブロックの側面の各縁部)のことを「側壁エッジ」と言う。正面側壁と側面側壁との間に面取りが形成されている場合、このような面取り部の各エッジは側壁エッジと解される。
このように構成された本発明においては、少なくとも1つの正面側壁に補強部を設けたことによる雪上性能向上の効果を、ブロックの摩耗後にも効果的に発揮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、雪上のように、その摩擦係数がブロックを変形させるのに十分大きな路面を走行するとき、少なくとも1つの正面側壁に形成された補強部の補強効果によって、補強部の一部を構成する波状部のバックリング変形を防止することが出来、これにより、局所的に高いエッジ圧力を得ることが出来る。従って、正面エッジを効果的に雪に食い込ませることが可能となり、その結果、雪上性能を向上させることが出来る。また、氷上のように、その摩擦係数がブロックを変形させるのに不十分なほど小さい路面を走行するとき、波状部の効果によって、ブロックの正面エッジ近傍部分に、接地圧力を減少させる方向のモーメント力を発生させることが出来る。従って、氷上における摩擦係数を低下させる原因の1つとしてよく知られている、トレッドと氷との間での水膜の発生を防止することが可能となり、その結果、氷上性能を向上させることが出来る。
本発明において、より好ましくは、この角度Aは70°以上である。
このように構成された本発明においては、ブロックに荷重がかかった場合に、正面エッジと***部とが平行でないことに起因するねじり力の発生を防止することが出来、その結果、波状部の耐久性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、波状部がブロックの高さhの60%以上且つ100%以下の所定距離Dにわたって形成されているので、少なくとも1つの正面側壁に設けられたそのような波状部の効果により、氷上性能を向上しつつ、少なくとも1つの正面側壁に設けられた補強部の効果により正面エッジを効果的に雪に食い込ませる効果をより効率的に発揮させることが可能となる。その結果、より効果的に氷上性能と雪上性能の両立を図ることが出来る。
ここで、所定距離Dとは、波状部において、タイヤ径方向最外側となる部分が***部であり且つタイヤ径方向最内側となる部分が***部である場合、タイヤ径方向最外側となる***部とタイヤ径方向最内側となる***部との間のタイヤ径方向に測定される距離である。又は、所定距離Dとは、波状部において、タイヤ径方向最外側となる部分が***部であり且つタイヤ径方向最内側となる部分が谷部である場合、タイヤ径方向最外側となる***部とタイヤ径方向最内側となる谷部との間のタイヤ径方向に測定される距離である。
このように構成された本発明においては、氷上のように、その摩擦係数がブロックを変形させるのに不十分なほど小さい路面を走行するとき、波状部の谷部によるブロックの十分な変形を確保しつつ、雪上のように、その摩擦係数がブロックを変形させるのに十分に大きい路面を走行するとき、補強部の補強効果により、波状部の谷部に起因するブロックの過大な変形をより効果的に防止することが出来る。従って、より効果的に局所的に高いエッジ圧力を得ることが出来、その結果、より効果的に氷上性能と雪上性能の両立を図ることが出来る。
言い換えると、このオフセット量ddを0.2mmよりも小さくすると、波状部の谷部によるブロックの十分な変形を確保することが難しくなる。即ち、オフセット量ddが0.2mmよりも小さいと、氷上のようにその摩擦係数がブロックを変形させるのに不十分なほど小さな路面を走行するとき、正面エッジ近傍部分の接地圧力を増大させてしまうので、氷上性能を低下させる恐れがある。
また、このオフセット量ddを3mmよりも大きくすると、雪上のようにその摩擦係数がブロックを変形させるのに十分大きい路面を走行するとき、補強部の補強効果による、波状部の谷部に起因するブロックの過大な変形を防止することが難しくなり、その結果、局所的に高いエッジ圧力を得ることが難しくなり、雪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、波状部の谷部の数の過度な増加(4以上)によるブロックの過度な変形を防止して、より効果的なブロックの変形を確保することが出来る。その結果、より効果的に氷上性能と雪上性能の両立を図ることが出来る。
このように構成された本発明においては、少なくとも1つの正面側壁に設けられた波状部自体の不均等な変形を予防することが可能となり、その結果、波状部及びブロックの耐久性を向上させることが出来る。言い換えると、この割合を1.3よりも大きくすると、荷重が付加された場合、波状部は不均等に変形しやすくなり、その結果、波状部の耐久性を低下させ、さらには、ブロックの耐久性も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、補強部により全体的に高められたブロック剛性を、細い切れ込みにより部分的に低下させて、ブロックと路面との密着性を向上させることが出来る。特に、氷上におけるブロックと路面との密着性を向上させることが出来、これにより、氷上性能を向上させることが出来る。
また、細い切れ込みは、雪上のように、その摩擦係数がブロックを変形させるのに十分に大きい路面を走行するとき、ブロックを変形させ易くすることが出来る。従って、正面エッジによる局所的に高いエッジ圧力をより効果的に高めて、正面エッジ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、細い切れ込みが少なくともブロックの上面に開口しているので、氷上における摩擦係数を低下させる原因の1つであ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空間として機能し、その結果、より氷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、補強部及び波状部が副溝に面する2つの正面側壁に設けられているので、上述した冬の路面における性能向上効果を、安全上最も重要な加速時や減速時に、より確実に発揮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、雪上のようにその摩擦係数がブロックを変形させるのに十分に大きい路面を走行するとき、正面エッジに、より確実に高いエッジ圧力を発生させることが可能であり、これにより、正面エッジをより確実に雪に食い込ませることが出来る。その結果、より雪上性能を向上させることが出来る。
本発明において、より好ましくは、補強部を構成する材料の弾性率Efがトレッド及びブロックを構成するゴム組成物の弾性率Etの40倍以上である。さらに、より好ましくは、補強部を構成する材料の弾性率Efは、氷上のようにその摩擦係数がブロックを変形させるのに不十分なほど小さい路面を走行するときに高いエッジ圧力が発生してしまうことを防止するために、トレッド及びブロックを構成するゴム組成物の弾性率Etの60倍以下である。
このように構成された本発明においては、雪上では、補強部の補強効果による高いエッジ圧力を発生させ、一方、氷上では、ブロック全体としての接地圧力をより均一にすることが出来、その結果、より確実に、氷上性能の維持を図りつつ雪上性能を向上させることが出来る。
言い換えると、補強部の平均厚さtを0.1mmより小さくすると、補強部によるブロックの補強効果が相対的に低下する。即ち、この補強効果の低下に起因して、雪上のようにその摩擦係数がブロックを変形させるのに十分大きい路面を走行するとき、波状部の谷部によるブロックの過大な変形を補強部によって防止する効果が低下し、雪上性能を低下させる恐れがある。また、補強部の平均厚さtを2.0mmより大きくすると、補強部によるブロックの補強効果が相対的に増大する。即ち、氷上のようにその摩擦係数がブロックを変形させるのに不十分なほど小さい路面を走行するとき、補強部の補強効果の増大に起因して、波状部の谷部によるブロックの変形し易さを妨げ、且つ、補強部に相対的に大きな荷重がかかって局所的に接地圧力を上げてしまうので、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、雪上のようにその摩擦係数がブロックを変形させるのに十分大きい路面を走行するとき、より確実に正面エッジに高いエッジ圧力を発生させることが可能であり、これにより、より確実に正面エッジを雪に食い込ませることが出来る。その結果、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、雪上のようにその摩擦係数がブロックを変形させるのに十分大きい路面を走行するとき、より確実に正面エッジに高いエッジ圧力を発生させることが可能である。従って、より確実に正面エッジを雪に食い込ませることが出来、これにより、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、補強部による雪上性能向上効果を発揮させつつ、波状部による氷上性能向上効果をトレッドの摩耗末期まで発揮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、波状部が少なくとも1つの正面側壁の正面エッジ及び側壁エッジから少なくとも0.5mm以上オフセットしているので、波状部が形成された部分以外の正面側壁の部分、即ち、正面エッジ及び側壁エッジからオフセットされた部分を形成することが出来る。そして、このオフセットされた部分(波状部以外の部分)は、雪上のようにその摩擦係数がブロックを変形させるのに十分大きい路面を走行するとき、波状部の谷部によるブロックの過大な変形を防止するための追加の補強部分となり、これにより、より確実に、雪上性能を向上させることが出来る。このオフセット量を0.5mmより小さくすると、上述した追加の補強部分による効果が薄れるばかりではなく、波状部が形成された部分以外の正面側壁の部分が変形に対して脆くなるので、ブロックの耐久性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、上述した補強部及び波状部による氷雪性能の向上効果を、例えば旋回時など、ブロック側面の側から力が加わるような状況においても発揮することが出来る。
先ず、図1及至図2により、本発明の第1実施形態によるタイヤ用トレッド及びこのトレッドを有するタイヤを説明する。図1は、本発明の第1実施形態による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線に沿って見たタイヤ用トレッドのブロックの拡大断面図である。
先ず、図1に示すように、このトレッド1は、ASTM D882-09に規定された引張試験から得られる弾性率Etを有する少なくとも1つのゴム組成物により形成され、タイヤ転動時に路面と接触する接地面2を有する。また、トレッド1には、タイヤ周方向に延びる2本の周方向主溝3及びタイヤ回転軸方向に延びる複数の副溝4が形成されている。さらに、トレッド1には、複数のブロック5が、これらの周方向主溝3及び副溝4により区画されて形成されている。
これらのブロック5は、接地面2の一部となる上面51と、タイヤ回転軸線方向に延び副溝4に面するように形成された2つの側壁(正面側壁)52,53と、タイヤ周方向に延び周方向主溝3に面するように形成された2つの側壁(側面側壁)54,55と、を有している。
また、ブロック5には、正面側壁52,53と側面側壁54,55とが交差する位置に4つの側壁エッジ561が形成されている。
ここで、トレッド1を形成するゴム組成物の弾性率Et、及び、補強部6を形成する材料の弾性率Efは、規格ASTM D882-09に規定された引張試験から求められた引張試験曲線から算出可能である。
図1及び図2に示すように、本実施形態では、各補強部6は、各正面側壁52,53の少なくとも一部を構成するようにそれぞれ設けられている。また、好ましくは、各補強部6は、各正面側壁52,53の全領域の70%以上の領域にわたって副溝4に面するようにそれぞれ設けられる。
また、各補強部6は、その平均厚さt(図2を参照)が2.0mm以下、好ましくは1.0mm以下となるように設けられる。ここで、補強部6の厚さtは、補強部6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に測定される。これらの補強部6の「平均厚さ」の値は、補強部6の副溝4の底面側の端縁からブロック5の上面51側の端縁までの間で測定される平均値、即ち、補強部6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6は、正面エッジ521,531を含み且つ正面側壁52,53の一部を構成するように設けられ、その平均厚さtは0.5mmである。ここで、補強部6の平均厚さtは、0.1mm以上且つ2.0mm以下であることが好ましく、0.2mm以上且つ1.0mm以下であることがさらに好ましい。
ここで、図1に示すように、本実施形態においては、正面側壁52,53に設けられた補強部6のタイヤ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が、補強部6のタイヤ径方向の最外側の縁部が、正面エッジ521,531の幅方向において部分的に存在するように設けられていても良い。
図1に示すように、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、正面側壁52,53と交差する位置に形成されタイヤ回転軸線方向に延びる正面エッジ521,531と、側面側壁54,55と交差する位置に形成されタイヤ周方向に延びる側面エッジ541,551と、を有し、これらの正面エッジ521,531と側面エッジ541,551とにより、その領域が制限されている。
図1及び図2に示すように、本実施形態では、各波状部7は、補強部6が設けられた正面側壁52,53において、その正面側壁52,53の少なくとも一部を構成すると共に補強部6の少なくとも一部を構成するように設けられる。この波状部7のタイヤ径方向最外側部は、タイヤ回転軸線方向に直線状に延び且つ幅W(図1参照)を有する***部72であり、この***部72は、補強部6が設けられた正面側壁52,53の正面エッジ521,531と平行に延びるように形成されている。他の***部72も同様に平行に直線状に延び、また、谷部71も同様に平行に直線状に延びるように形成されている。
また、各波状部7は、少なくとも2つの***部72及び少なくとも1つの谷部71を有し、谷部71の数が3以下となるように構成されている。本実施形態においては、波状部7は、3つの***部72と2つの谷部71を有している。本実施形態において、波状部7とは、タイヤ回転軸線方向に延びる幅W(図1参照)を有し、タイヤ径方向最外側の***部72から、タイヤ径方向最内側の***部72までにわたりタイヤ径方向に距離D(図2参照)にわたって形成された領域の部分を言う。
次に、図1に示すように、各波状部7は、ブロック5の正面側壁52,53の正面エッジ521,531、及び、正面側壁52,53と側面側壁54,55との交差部である側壁エッジ561から少なくとも0.5mm以上オフセットして設けられている。本実施形態においては、波状部7の正面エッジ521,531からのオフセット量duは1.0mmであり、側壁エッジ561からの各オフセット量dl、drは、いずれも1.25mmである。
図2に示すように、本実施形態では、ブロックの上面51及び正面エッジ521,531に垂直な断面視において、タイヤ径方向の補強部6の長さLrが、ブロック5の高さhの80%以上となるように形成されている。本実施形態においては、ブロック5の高さhは10mmであり、補強部6の長さLrは8mmである。従って、補強部6の長さLrはブロック5の高さhの80%となるように形成されている。なお、図3及び図4に示す後述する第2実施形態においては、補強部6の長さLrはブロック5の高さhの100%となっている。
なお、このブロックの高さhは、正面側壁52,53が面している副溝4のタイヤ径方向最深部とブロック5の上面51との間でタイヤ径方向に測定される。
次に、本実施形態では、波状部7において、タイヤ径方向最外側の***部72とタイヤ径方向最内側の***部72との間のタイヤ径方向の距離(図2に示す、Dの距離)が、ブロック5の高さhの60%以上、となるように形成されている。なお、図3及び図4に示す第2実施形態では、波状部7の距離Dがブロック5の高さhの100%となる。本実施形態においては、波状部7において、タイヤ径方向最外側の***部72とタイヤ径方向最内側の***部72との間の距離Dは8mmである。従って、波状部7において、タイヤ径方向最外側の***部72とタイヤ径方向最内側の***部72との間の距離Dはブロック5の高さhの80%となるように形成されている。
なお、このような距離Dは、後述する第2実施形態(特に図4参照)のように、波状部7において、タイヤ径方向最外側の部分が***部72となり、且つ、タイヤ径方向最内側の部分が谷部71である場合(この場合、波状部7とは、幅Wを有し、タイヤ径方向最外側の***部72から、タイヤ径方向最内側の谷部71までのタイヤ径方向に距離D(図2参照)にわたって形成された領域の部分を言う。)は、波状部7において、タイヤ径方向最外側の***部72とタイヤ径方向最内側の谷部71との間のタイヤ径方向の距離(図4に示す、Dの距離)である。
なお、後述する第2実施形態(図3及び図4参照)のように、各波状部7は少なくとも2つの***部72と少なくとも2つの谷部71を有し、波状部7において、タイヤ径方向最外側の部分が***部72であり、且つ、タイヤ径方向最内側の部分が谷部71である場合、各波状部7においてタイヤ径方向の距離である、谷部71にタイヤ径方向に隣接する2つの***部72間の最小距離又は最大距離(Dmini又はDmaxi、例えば図4に示す距離D3)、又は、波状部7におけるタイヤ径方向最内側部である谷部71とこの谷部71にタイヤ径方向に隣接する***部72間の最小距離又は最大距離(Dmini又はDmaxi、例えば図4に示す距離D4)との割合(Dmaxi/Dmini)が、1.0以上且つ1.3以下となるように形成されている。
このように、これらの最小距離Dmini及び最大距離Dmaxiは、波状部7のタイヤ径方向最内側となる部分が***部72である場合(第1実施形態)は、谷部71にタイヤ径方向に隣接する2つの***部72間の距離、及び、他の谷部71にタイヤ径方向に隣接する2つの***部72間の距離となる。また、波状部7のタイヤ径方向最内側となる部分が谷部71である場合(後述する第2実施形態)は、谷部71にタイヤ径方向に隣接する2つの***部72間の距離、又は、波状部7におけるタイヤ径方向最内側部である谷部71とこの谷部71にタイヤ径方向に隣接する***部72間の距離となる。
言い換えると、波状部7における最小距離Dmini及び最大距離Dmaxiは、タイヤ径方向最外側となる部分が***部72であり且つタイヤ径方向最内側となる部分が***部72である場合は、少なくとも2組の「谷部71にタイヤ径方向に隣接する2つの***部72の間の距離」のいずれかから選択される。例えば、***部72が4つ形成されると共に谷部71が3つ形成されるような場合、上述した最小距離Dmini及び最大距離Dmaxiは、3組の「谷部71にタイヤ径方向に隣接する2つの***部72の間の距離」のいずれかから選択される。
また、波状部7における最小距離Dmini及び最大距離Dmaxiは、タイヤ径方向最外側となる部分が***部72であり且つタイヤ径方向最内側となる部分が谷部71である場合は、少なくとも1組の「谷部71にタイヤ径方向に隣接する2つの***部72の間の距離」及び1組の「波状部7におけるタイヤ径方向最内側部である谷部71とこの谷部71にタイヤ径方向に隣接する***部72間の距離」のいずれかから選択される。例えば、タイヤ径方向最内側となる部分が谷部71であり、***部72が5つ形成されると共に谷部71が3つ形成されるような場合、上述した最小距離Dmini及び最大距離Dmaxiは、4組の「谷部71にタイヤ径方向に隣接する2つの***部72の間の距離」及び1組の「波状部7におけるタイヤ径方向最内側部である谷部71とこの谷部71にタイヤ径方向に隣接する***部72間の距離」のいずれかから選択される。
なお、上述したタイヤ用トレッド1は、特に冬用タイヤに好適である。
氷上のようにその摩擦係数がブロック5を変形させるのに不十分なほど小さい路面を走行し、タイヤの回転方向に発生する駆動力、制動力が付加されるときには、本実施形態のように、補強部6が正面側壁52,53の大部分の領域に設けられていても、波状部7の***部72及び谷部71の形状、特に谷部71を形成することによってブロック5が変形し易くなるので、正面エッジ部521,531において高いエッジ圧力が発生することが抑制される。さらに、角度Aを90度以下としているので、このような条件下ではブロック5の波状部7には幾何学的に正面エッジ部521,531におけるエッジ圧力を減少させる方向に作用するモーメント力が発生する。これらにより、本実施形態のトレッド1では、氷上における摩擦係数を低下させる原因の1つとしてよく知られている、トレッドと氷との間での水膜の発生を防止することが可能となり、その結果、氷上性能を向上させることが出来る。
補強部6の平均厚さtは0.1mm以上且つ2.0mm以下であり、好ましくは0.2mm以上且つ1.0mm以下である。この補強部6の平均厚さtは、同一のブロック5の正面側壁52,53とで互いに異なるようにしてもよい。
また、上述したように正面側壁52,53の少なくとも一部の領域に設けられる補強部6は、同一ブロック5の正面側壁52,53とでそれぞれ異なる割合の領域に設けるようにしてもよい。
また、波状部7は、上述したように正面側壁52,53において、その正面側壁52,53の少なくとも一部を構成すると共に補強部6の少なくとも一部を構成するように設けられるが、同一のブロック5の正面側壁52,53とで互いに異なるようにしてもよく、同一のブロック5の正面側壁52,53とでそれぞれ異なる割合の領域に設けられるようにしてもよい。
なお、この第2実施形態では、主に、上述した第1実施形態と異なる構成を説明し、同様の構成については、その説明を省略する。
次に、補強部6が設けられた正面側壁52,53において、ブロック5の上面51に沿って延び正面エッジ521,531を通る仮想直線と、波状部7のタイヤ径方向最外側の***部72と、この***部72のタイヤ径方向に隣接した谷部71とを接続する仮想直線との間の角度Aが、60°以上且つ90°以下、好ましくは70°以上且つ90°以下となるように形成される。本実施形態においては、角度Aは78°である。
次に、本実施形態では、タイヤ径方向最外側となる***部72とタイヤ径方向最内側となる谷部71との間の距離(図4に示すDの距離)が、ブロック5の高さhの60%以上、となるように形成されている。本実施形態では、波状部7は正面側壁52,53の全領域にわたって設けられているので、波状部7のタイヤ径方向最外側となる***部72とタイヤ径方向最内側となる谷部71との間の距離(図4に示すDの距離)はブロック5の高さhの100%となるように形成されている。
第2実施形態では、補強部6及び波状部7が、正面側壁52,53の全領域にわたって設けられている。これにより第2実施形態では、補強部6による雪上性能向上効果を発揮しつつ、上述した第1実施形態における作用効果に加えて、トレッド1のブロック5の摩耗が進行した状態であっても、波状部7による氷上性能向上効果を発揮させることが可能となる。また、波状部7のタイヤ径方向最内側の部分が谷部71となっているので、例えば、ブロック5が、その高さhの70%以上に摩耗したような状態であっても、補強部6との相乗効果により波状部7のバックリング変形を防止することができる。これにより、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な路面を走行するとき、ブロック5の摩耗が進行した状態であっても、局所的に高いエッジ圧力を得る効果を発揮させることが出来る。従って、正面エッジ521,531を効果的に雪に食い込ませることが可能となり、その結果、高い雪上性能を長期に渡って保つことが出来る。また、氷上のように路面の摩擦係数がブロックを変形させるのに不十分な路面を走行するとき、波状部7の効果によりブロック5の正面エッジ521,531の近傍の部分に、接地圧力を減少させる方向のモーメント力を発生させることが出来る。従って、氷上における摩擦係数を低下させる原因の1つとしてよく知られている、トレッドと氷との間での水膜の発生を防止することが可能となり、その結果、高い氷上性能を長期に渡って保つことが出来る。
なお、この第3実施形態では、主に、上述した第1及び第2の実施形態と異なる構成を説明し、同様の構成については、その説明を省略する。
本実施形態においては、波状部7は、正面側壁52,53においては2つの***部72と2つの谷部71を有し、また、側面側壁54,55においては3つの***部72と2つの谷部71を有している。さらに、波状部7は、正面側壁52,53及び側面側壁54,55の両方において、各補強部6の全領域を構成するように設けられている。
第3実施形態では、補強部6及び波状部7が、正面側壁52,53に加えて、さらに側面側壁54,55にも設けられている。これにより第3実施形態では、上述した第1及び第2の実施形態における作用効果に加えて、補強部6及び波状部7による氷上性能及び雪上性能の向上効果を、旋回時も得ることが可能となるので、より安全に氷雪路面を走行することが出来る。
この従来技術によるタイヤ用トレッド101では、ブロック105の正面側壁152、153に、波状部は設けられていない。
シミュレーションで用いた従来例及び実施例に係る2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、上面において短辺長さ12mm、長辺長さ15mm、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8mmと設定した。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、平均厚さを0.5mmにて正面側壁の全領域にわたって設けられており、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倍となるように設定した。
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
541,551 側面エッジ
561 側壁エッジ
6 補強部
7 波状部
71 ***部
72 谷部
8 細い切れ込み(サイプ)
Claims (19)
- 少なくとも1つのゴム組成物により形成され、タイヤ転動時に路面と接触する接地面(2)を有するタイヤ用トレッド(1)であって、
前記少なくとも1つのゴム組成物はASTM D882-09に規定された引張試験から得られる弾性率Etを有し、
前記トレッド(1)は、タイヤ周方向に延びる少なくとも1本の周方向主溝(3)と、タイヤ回転軸線方向に延びる複数の副溝(4)と、これらの周方向主溝(3)及び副溝(4)によって区切られた複数のブロック(5)と、を有し、
これらの複数のブロック(5)の各々は、トレッド(1)の接地面(2)となる上面(51)と、タイヤ回転軸線方向に延び前記副溝(4)に面する2つの正面側壁(52,53)と、タイヤ周方向に延び前記周方向主溝(3)に面する2つの側面側壁(54,55)と、を有し、
前記ブロック(5)の上面(51)は、前記正面側壁(52,53)と交差する位置に形成されタイヤ回転軸線方向に延びる正面エッジ(521,531)と、前記側面側壁(54,55)と交差する位置に形成されタイヤ周方向に延びる側面エッジ(541,551)と、を有し、
前記ブロック(5)は、前記側壁(52,53,54,55)のうち少なくとも1つの正面側壁(52,53)に設けられた、平均厚さtの補強部(6)を有し、この補強部(6)は、前記トレッド(1)及び前記ブロック(5)を形成する前記ゴム組成物の弾性率Etよりも高い弾性率Efを有し、
前記補強部(6)が設けられた前記少なくとも1つの正面側壁(52,53)には、少なくとも2つの***部(72)及び少なくとも1つの谷部(71)を有する波状部(7)が形成され、この波状部(7)は、前記補強部(6)が設けられた前記少なくとも1つの正面側壁(52,53)において、前記正面側壁(52,53)の少なくとも一部を構成すると共に前記補強部(6)の少なくとも一部を構成するように設けられることを特徴とするタイヤ用トレッド。 - 前記ブロック(5)の前記補強部(6)のタイヤ径方向の長さLrが前記ブロック(5)の高さhの80%以上且つ100%以下である、請求項1に記載のタイヤ用トレッド。
- 前記補強部(6)が設けられた前記少なくとも1つの正面側壁(52,53)において、前記ブロック(5)の上面(51)に沿って延び前記正面エッジ(521,531)を通る仮想直線と、前記波状部(7)の径方向最外側の***部(72)とこの***部(72)に隣接した谷部(71)とを接続する仮想直線との間のタイヤ回転軸線方向から見た角度Aが60°以上且つ90°以下である、請求項1又は請求項2に記載のタイヤ用トレッド。
- 前記補強部(6)が設けられた前記少なくとも1つの正面側壁(52,53)において、前記波状部(7)の径方向最外側部は***部(72)であり、この***部(72)と、前記正面エッジ(521,531)とは平行に延びる、請求項1及至3の何れか1項に記載のタイヤ用トレッド。
- 前記補強部(6)が設けられた前記少なくとも1つの正面側壁(52,53)において、前記波状部(7)は、所定の幅Wを有し且つタイヤ径方向に所定距離Dにわたって形成され、この所定距離Dが、前記ブロック(5)の高さhの60%以上且つ100%以下である、請求項1及至4の何れか1項に記載のタイヤ用トレッド。
- 前記補強部(6)が設けられた前記少なくとも1つの正面側壁(52,53)において、前記ブロック(5)の上面(51)に沿って延び前記正面エッジ(521,531)を通る方向の、前記波状部(7)における***部(72)と谷部(71)との間のオフセット量ddが、0.2mm以上且つ3mm以下である、請求項1及至5の何れか1項に記載のタイヤ用トレッド。
- 前記波状部(7)における谷部(71)の数は3以下である、請求項1及至6の何れか1項に記載のタイヤ用トレッド。
- 前記波状部(7)は、少なくとも3つの***部(72)と少なくとも2つの谷部(71)を有し、前記波状部(7)のタイヤ径方向最内側部は***部(72)であり、
前記ブロック(5)のタイヤ径方向の距離である、前記波状部(7)の各谷部(71)にタイヤ径方向に隣接する2つの***部(72)間の最も小さい最少距離Dminiと、前記波状部(7)の各谷部(71)にタイヤ径方向に隣接する2つの***部(72)間の最も大きい最大距離Dmaxiとの割合(Dmaxi/Dmini)が、1.0以上且つ1.3以下である、請求項1及至7の何れか1項に記載のタイヤ用トレッド。 - 前記波状部(7)は、少なくとも2つの谷部(71)を有し、前記波状部(7)のタイヤ径方向最内側部は谷部(71)であり、
前記ブロック(5)のタイヤ径方向の距離である、前記波状部(7)の各谷部(71)にタイヤ径方向に隣接する2つの***部(72)間の距離又は前記の波状部(7)におけるタイヤ径方向最内側部である谷部(71)とこの谷部(71)にタイヤ径方向に隣接する***部(72)間の距離のそれぞれの距離のうちいずれか最も小さい最少距離Dminiと、前記波状部(7)の各谷部(71)にタイヤ径方向に隣接する2つの***部(72)間の距離又は前記の波状部(7)におけるタイヤ径方向最内側部である谷部(71)とこの谷部(71)にタイヤ径方向に隣接する***部(72)間の距離のそれぞれの距離のうちいずれか最も大きい最大距離Dmaxiとの割合(Dmaxi/Dmini)が、1.0以上且つ1.3以下である、請求項1及至7の何れか1項に記載のタイヤ用トレッド。 - 前記ブロック(5)が、少なくともその上面(51)に開口し、タイヤ径方向に延びる少なくとも1つの細い切れ込み(8)を有する、請求項1及至9の何れか1項に記載のタイヤ用トレッド。
- 前記補強部(6)及び前記波状部(7)が、前記ブロック(5)の前記2つの正面側壁(52,53)に設けられている、請求項1及至10の何れか1項に記載のタイヤ用トレッド。
- 前記補強部(6)を構成する材料の弾性率Efが、前記トレッド(1)及び前記ブロック(5)を構成する前記ゴム組成物の弾性率Etの少なくとも20倍以上である、請求項1及至11の何れか1項に記載のタイヤ用トレッド。
- 前記補強部(6)の平均厚さtが0.1mm以上且つ2.0mm以下である請求項1及至12に記載のタイヤ用トレッド。
- 前記補強部(6)が、前記少なくとも1つの正面側壁(52、53)の全領域にわたって設けられている、請求項1及至13の何れか1項に記載のタイヤ用トレッド。
- 前記波状部(7)が前記正面エッジ(521、531)の少なくとも一部を含む、請求項1及至14の何れか1項に記載のタイヤ用トレッド。
- 前記波状部(7)が前記少なくとも1つの正面側壁(52、53)の全領域にわたって設けられている、請求項1及至15の何れか1項に記載のタイヤ用トレッド。
- 前記ブロック(5)は、さらに、前記補強部(6)が設けられた前記少なくとも1つの正面側壁(52,53)と前記側面側壁(54,55)とが交差する位置に形成された側壁エッジ(561)を有し、
前記波状部(7)が前記少なくとも1つの正面側壁(52、53)の正面エッジ(521,531)及び前記側壁エッジ(561)から少なくとも0.5mm以上オフセットして設けられている、請求項1及至14の何れか1項に記載のタイヤ用トレッド。 - 前記ブロック(5)は、さらに、その側面側壁(54,55)の少なくとも1つが前記補強部(6)及び前記波状部(7)を有する、請求項1及至17の何れか1項に記載のタイヤ用トレッド。
- 請求項1及至18の何れか1項に記載のトレッドを有することを特徴とするタイヤ。
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BR112016023505A BR112016023505A2 (pt) | 2014-04-10 | 2015-04-10 | banda de rodagem de pneumático e pneumático |
JP2016512793A JPWO2015156397A1 (ja) | 2014-04-10 | 2015-04-10 | タイヤ用トレッド及びタイヤ |
CN201580019038.6A CN106170402B (zh) | 2014-04-10 | 2015-04-10 | 轮胎胎面和轮胎 |
EP15777526.3A EP3118024B1 (en) | 2014-04-10 | 2015-04-10 | Tire tread, and tire |
RU2016143674A RU2016143674A (ru) | 2014-04-10 | 2015-04-10 | Протектор шины и шина |
US15/301,394 US20170015142A1 (en) | 2014-04-10 | 2015-04-10 | Tire tread, and tire |
CA2941524A CA2941524A1 (en) | 2014-04-10 | 2015-04-10 | Tyre tread, and tyre |
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JP2019064481A (ja) * | 2017-10-02 | 2019-04-25 | 株式会社ブリヂストン | タイヤ |
JP7384017B2 (ja) | 2019-12-13 | 2023-11-21 | 住友ゴム工業株式会社 | タイヤ |
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JP6891556B2 (ja) * | 2017-03-14 | 2021-06-18 | 住友ゴム工業株式会社 | タイヤ |
CN108353576A (zh) * | 2017-12-29 | 2018-08-03 | 郭昌普 | 一种镇压覆土效果好的小型花生播种机 |
DE202019106882U1 (de) | 2019-12-10 | 2020-03-09 | Apollo Tyres Global R&D B.V. | Reifenlauffläche |
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2015
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- 2015-04-10 EP EP15777526.3A patent/EP3118024B1/en active Active
- 2015-04-10 CA CA2941524A patent/CA2941524A1/en not_active Abandoned
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JP7384017B2 (ja) | 2019-12-13 | 2023-11-21 | 住友ゴム工業株式会社 | タイヤ |
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RU2016143674A (ru) | 2018-05-11 |
CN106170402B (zh) | 2018-09-21 |
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EP3118024A4 (en) | 2017-11-29 |
CN106170402A (zh) | 2016-11-30 |
JPWO2015156397A1 (ja) | 2017-04-13 |
CA2941524A1 (en) | 2015-10-15 |
EP3118024A1 (en) | 2017-01-18 |
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US20170015142A1 (en) | 2017-01-19 |
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