tire

Abstract

To further improve on-snow performance while maintaining wear resistance.SOLUTION: A tire 1 has a first crown block 6 comprising: a tread 13; and a block wall surface 14. The block wall surface 14 comprises: a first block wall surface 15 adjacent to a crown groove 9; and a second block wall surface 16 which is adjacent to a first shoulder peripheral groove 3. The first block wall surface 15 has, in a range of 50% or greater of a length L1 of the first block wall surface 15, a chamfer part 20 which is formed on the tread 13 side. The second block wall surface 16 has no chamfer part, or, has in a range of less than 50% of a length L2 of the second block wall surface 16, the chamfer part 20.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] This disclosure relates to tires.

Background Art

[0002] Patent Document 1 below describes a tire provided with a plurality of crown blocks in a tread portion. The crown block includes a chamfered portion arranged to surround the entire circumference of the tread surface, and a stepped portion provided radially inward of the tire than the chamfered portion.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, for tires, especially tires for SUVs, there has been a demand to further improve snow performance while maintaining wear resistance performance.

[0005] This disclosure has been devised in view of the above actual situation, and the main object is to provide a tire that can further improve snow performance while maintaining wear resistance performance.

Means for Solving the Problems

[0006] This disclosure relates to a tire having a tread portion, the tread portion comprising a first tread end, a first shoulder circumferential groove disposed between the first tread end and the tire equator and adjacent to the first tread end, a plurality of crown blocks disposed inward in the tire axial direction of the first shoulder circumferential groove, and a plurality of crown grooves disposed inward in the tire axial direction of the first shoulder circumferential groove and separating the plurality of crown blocks, the plurality of crown blocks comprising a plurality of first crown blocks adjacent to the first shoulder circumferential groove, and each of the plurality of first crown blocks The tire comprises a tread and a block wall surface extending inward from the tread in the radial direction of the tire, wherein the block wall surface comprises a first block wall surface adjacent to the crown groove and a second block wall surface adjacent to the first shoulder circumferential groove, the first block wall surface has a chamfer formed on the tread side over a range of 50% or more of the length of the first block wall surface measured along the tread, and the second block wall surface either does not have a chamfer formed on the tread side, or has a chamfer formed on the tread side over a range of less than 50% of the length of the second block wall surface measured along the tread. [Effects of the Invention]

[0007] By adopting the above configuration, the tire disclosed herein can further improve snow performance while maintaining wear resistance. [Brief explanation of the drawing]

[0008] [Figure 1] This is a plan view of the tread portion of one embodiment of the present disclosure. [Figure 2] Figure 1 is a plan view of the first crown block. [Figure 3] (a) is a cross-sectional view along line AA in Figure 1, and (b) is a cross-sectional view along line BB in Figure 1. [Figure 4] This is a plan view of a horizontally elongated block. [Figure 5] Figure 1 is a plan view of the second crown block. [Figure 6]Figure 1 is a cross-sectional view along the CC line. [Figure 7] This is a plan view of the shoulder block. [Figure 8] Figure 7 is a cross-sectional view of the DD line. [Figure 9] This is a plan view of the tread portion of another embodiment. [Modes for carrying out the invention]

[0009] One form of implementation of this disclosure will be described below with reference to the drawings. Figure 1 is a plan view of the tread portion 2 of the tire 1 of this embodiment in an unfolded state. This disclosure applies, for example, to pneumatic tires for SUVs suitable for driving on rough terrain. This disclosure can also be applied to pneumatic tires 1 for passenger cars or heavy loads, as well as to non-pneumatic tires 1 that are not filled with compressed air.

[0010] As shown in Figure 1, the tread portion 2 of this embodiment includes a first tread end T1, a first shoulder circumferential groove 3, a plurality of crown blocks 5, and a plurality of crown grooves 9. The first shoulder circumferential groove 3 is located between the first tread end T1 and the tire equator C, and is adjacent to the first tread end T1. The plurality of crown blocks 5 are located on the tire axial side of the first shoulder circumferential groove 3. The plurality of crown grooves 9 are located on the tire axial side of the first shoulder circumferential groove 3 and divide the plurality of crown blocks 5.

[0011] The multiple crown blocks 5 include multiple first crown blocks 6 adjacent to the first shoulder circumferential groove 3. Each of the multiple first crown blocks 6 includes a tread surface 13 and a block wall surface 14 extending inward from the tread surface 13 in the tire radial direction.

[0012] The block wall surface 14 includes a first block wall surface 15 adjacent to the crown groove 9 and a second block wall surface 16 adjacent to the first shoulder circumferential groove 3. In other words, the second block wall surface 16 is positioned further outward in the tire axial direction than the first block wall surface 15.

[0013] Figure 2 is an enlarged view of the first crown block 6. Figure 3(a) is a cross-sectional view along line AA in Figure 1, and Figure 3(b) is a cross-sectional view along line BB in Figure 1. As shown in Figures 2 and 3, the first block wall surface 15 has a chamfered portion 20 formed on the tread surface 13 side in a range of 50% or more of the length L1 of the first block wall surface 15 measured along the tread surface 13. Such a first block wall surface 15 has high rigidity and enhances the basic wear resistance of the block. The second block wall surface 16 either does not have a chamfered portion formed on the tread surface 13 side, or a chamfered portion 20 is formed on the tread surface 13 side in a range of less than 50% of the length L2 of the second block wall surface 16 measured along the tread surface 13. Such a second block wall surface 16 exhibits a high edge effect on snowy roads and improves snow performance. In addition, since a relatively small ground pressure acts on the second block wall surface 16, wear is suppressed even if a chamfered portion 20 is not provided. Therefore, the tire 1 of this embodiment can further improve snow performance while maintaining wear resistance. In addition, such a tire 1 has excellent handling stability and wet performance. The second block wall surface 16 of this embodiment does not have a chamfered portion formed on the tread surface 13 side, so it exhibits high snow performance.

[0014] To improve wear resistance, it is desirable that the chamfered portion 20 be provided on the first block wall surface 15 over a range of 70% or more of the length L1 of the first block wall surface 15, and more preferably over a range of 85% or more. In this embodiment, the chamfered portion 20 is formed on the first block wall surface 15 over a range of 100% of the length L1 of the first block wall surface 15. In a plan view of the tread, the first block wall surface 15 extends in a zigzag pattern. In this specification, the length L1 of the first block wall surface 15 is defined as the sum of the lengths of the linearly extending portions, and in the first crown block 6 of Figure 2, it is the sum of lengths L1a, L1b, L1c, L1d, and L1e. The length L2 of the second block wall 16 is also defined as the sum of the lengths of the straight-line portions, and in the first crown block 6 in Figure 2, it is the sum of lengths L2a, L2b, L2c, L2d, L2e, and L2f.

[0015] The angle θ1 of the tread surface 13 of the chamfered portion 20 with respect to the normal line n1 is desirably 10 degrees or more, more desirably 15 degrees or more, desirably 30 degrees or less, and more desirably 25 degrees or less. Since the angle θ1 of the chamfered portion 20 is 10 degrees or more, the wear resistance performance is maintained high. Also, since the drainage performance is enhanced, the wet performance is improved. Since the angle θ1 of the chamfered portion 20 is 30 degrees or less, high snow performance is exhibited.

[0016] The first block wall surface 15 includes a wall surface main body 21 extending inward in the tire radial direction from the chamfered portion 20. In the present embodiment, the wall surface main body 21 includes a linear portion 22 extending linearly in the tire radial direction, and an arcuate portion 23 extending in an arcuate shape by connecting the linear portion 22 and the groove bottom 9s of the crown groove 9. Note that the wall surface main body 21 is not limited to such a mode. For example, a mode including an arcuate portion 23 and a large arcuate portion (not shown) that is arcuate with a larger radius of curvature than the arcuate portion 23 by connecting the arcuate portion 23 and the chamfered portion 20 may also be used.

[0017] The difference (θ1 - θ2) between the angle θ1 of the chamfered portion 20 and the angle θ2 of the wall surface main body 21 with respect to the normal line n1 is desirably 10 degrees or more, more desirably 15 degrees or more, desirably 30 degrees or less, and more desirably 25 degrees or less. Since the difference (θ1 - θ2) is 10 degrees or more, the rigidity of the first crown block 6 can be maintained high and the wear resistance performance is maintained. Since the difference (θ1 - θ2) is 30 degrees or less, the shearing force of the snow road surface by the wall surface main body 21 is ensured and the snow performance is enhanced. The angle θ2 of the wall surface main body 21 is specified by the angle of the linear portion 22.

[0018] The length H1 of the chamfered portion 20 in the tire radial direction is desirably 20% or more, more desirably 25% or more, desirably 40% or less, and more desirably 35% or less of the length Ha of the block wall surface 14 in the tire radial direction. Since the length H1 of the chamfered portion 20 is 20% or more of the length Ha of the block wall surface 14, the wear resistance performance is maintained. Since the length H1 of the chamfered portion 20 is 40% or less of the length Ha of the block wall surface 14, the effect of improving the snow performance is ensured.

[0019] As shown in FIG. 3(b), in this embodiment, the second block wall surface 16 is formed of a wall surface main body 21 including a linear portion 22 and an arcuate portion 23. The second block wall surface 16 is formed only of the wall surface main body 21, for example, at 100% of the length L2 of the second block wall surface 16 measured along the tread surface 13.

[0020] As shown in FIG. 1, in the tread portion 2 of this embodiment, a point-symmetrical pattern that is point-symmetrical with an arbitrary point on the tire equator C as the center of symmetry is adopted. As a result, a pair of first tread ends T1, T1 and a pair of first shoulder circumferential grooves 3, 3 are provided in the tread portion 2 of this embodiment. Note that the tread portion 2 may be formed, for example, as a line-symmetrical pattern that is line-symmetrical with the tire equator C as the target axis. Further, the tread portion 2 is not limited to the point-symmetrical pattern or the line-symmetrical pattern.

[0021] The first tread end T1 is defined as the outermost grounding position in the tire axial direction when a normal load is applied to the tire 1 in the normal state and the tire is grounded on a plane at a camber angle of 0 degrees. The distance in the tire axial direction between the first tread ends T1, T1 is the tread width TW.

[0022] The "normal state" means that the tire 1 is unloaded with a normal rim (not shown) mounted and filled with a normal internal pressure. Unless otherwise specified, the dimensions of each part of the tire 1 are the values measured in this normal state.

[0023] The "normal rim" is a rim determined for each tire in a standard system including the standard on which the tire is based. In the case of JATMA, it is the "standard rim", in the case of TRA, it is the "Design Rim", and in the case of ETRTO, it is the "Measuring Rim".

[0024] The aforementioned "standard internal pressure" refers to the air pressure specified for each tire by each standard within the standards system, including the standard on which the tire is based. For JATMA, this is the "maximum air pressure," for TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES," and for ETRTO, it is the "INFLATION PRESSURE."

[0025] The aforementioned "standard load" refers to the load specified for each tire in the standards system, including the standard on which the tire is based. For JATMA, this is the "maximum load capacity," for TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES," and for ETRTO, it is the "LOAD CAPACITY."

[0026] The outer end 15e of the first block wall surface 15 in the tire axial direction is located at a distance Lb in the tire axial direction from the tire equator C, which is 40% to 60% of the tread width TW. Furthermore, a chamfered portion 20 is formed on the outer end 15e of the first block wall surface 15. This ensures that high wear resistance is maintained.

[0027] The crown groove 9 includes a plurality of crown lateral grooves 10 extending in the tire axial direction, connecting the first shoulder circumferential grooves 3, 3, and a plurality of crown connecting grooves 11 connecting adjacent crown lateral grooves 10, 10 in the tire circumferential direction. The crown lateral grooves 10 extend, for example, in a zigzag shape. In this embodiment, the crown connecting grooves 11 include a first crown connecting groove 11A extending linearly along the tire equator C, and a second crown connecting groove 11B extending in an L-shape, offset from the tire equator C in the tire axial direction.

[0028] In this embodiment, the first crown block 6 includes a horizontally elongated block 6A whose length in the tire circumferential direction is shorter than the length in the tire axial direction, and a vertically elongated block 6B whose length in the tire circumferential direction is longer than the length in the tire axial direction. The horizontally elongated block 6A and the vertically elongated block 6B are arranged alternately, for example, in the tire circumferential direction. The first crown block 6 shown in Figure 2 is a vertically elongated block 6B.

[0029] Figure 4 is a plan view of the horizontal block 6A. As shown in Figures 2 and 4, in this embodiment, the horizontal block 6A and the vertical block 6B are provided with chamfered portions 20 over an area of ​​50% or more of the length L1 of the first block wall surface 15. It is preferable that the horizontal block 6A and the vertical block 6B have chamfered portions 20 over an area of ​​85% or more of the length L1, and more specifically, it is even more preferable that the chamfered portions 20 have been provided over an area of ​​100% of the length L1. In addition, in this embodiment, the horizontal block 6A and the vertical block 6B are formed only of the wall surface body 21, and no chamfered portions 20 are formed on the second block wall surface 16. As shown in Figure 4, the length L1 of the first block wall surface 15 of the horizontal block 6A is the sum of lengths L1g, L1h, L1i, L1j, L1k, and L1m. The first block wall surface 15 and the second block wall surface 16 of the horizontally elongated block 6A have, for example, the vertical cross-sectional shape shown in Figures 3(a) and (b).

[0030] As shown in Figure 1, the horizontally elongated block 6A is divided into adjacent crown lateral grooves 10, 10 in the circumferential direction of the tire, the first shoulder circumferential groove 3, and the first crown joint groove 11A. The vertically elongated block 6B is divided into adjacent crown lateral grooves 10, 10 in the circumferential direction of the tire, the first shoulder circumferential groove 3, and the second crown joint groove 11B.

[0031] As shown in Figure 4, the elongated block 6A is provided with a crown sipe 24. The crown sipe 24 includes a first crown sipe 25 and a second crown sipe 26. The first crown sipe 25 has one end 25i connected to the first block wall surface 15 and the other end 25e terminated on the tread surface 13. The first crown sipe 25 extends in a straight line. The second crown sipe 26 has one end 26i connected to the second block wall surface 16 and the other end 26e terminated on the tread surface 13. The second crown sipe 26 has a bent portion 27 that bends at an obtuse angle. Such an elongated block 6A exhibits a high edge effect and suppresses a decrease in block rigidity. In this specification, a sipe refers to a notched shape with a width of less than 1.5 mm and is distinguished from a groove-shaped body with a groove width of 1.5 mm or more.

[0032] As shown in Figure 1, the multiple crown blocks 5 further include multiple second crown blocks 7 positioned inward from the tire axial direction of the first crown block 6. Each of the multiple second crown blocks 7 is located on the tire equator C.

[0033] Figure 5 is a plan view of the second crown block 7. As shown in Figure 5, the second crown block 7 includes a tread surface 13 and a block wall surface 14 extending inward from the tread surface 13 in the radial direction of the tire. The block wall surface 14 of each second crown block 7 is formed only by the first block wall surface 15 adjacent to the crown groove 9. The block wall surface 14 of the second crown block 7 has a chamfered portion 20 formed on the tread surface 13 side over a range of 50% or more of the length L3 of the block wall surface 14 measured along the tread surface 13. Such a second crown block 7 maintains even higher wear resistance. It is desirable that the chamfered portion 20 be provided over a range of 70% or more of the length L3 of the block wall surface 14 of the second crown block 7, and preferably over a range of 85% or more. In this embodiment, the block wall surface 14 of the second crown block 7 has a chamfered portion 20 formed over a range of 100% of the length L3 of the block wall surface 14. In the second crown block 7, the length L3 of the block wall surface 14 is expressed as the sum of the linearly extending portions, similar to the length L1 of the first block wall surface 15. In this embodiment, it is the sum of lengths L3a to L3k and length L3m. For convenience, the sipes on the tread surface 13 have been removed from Figure 5.

[0034] The block wall surface 14 of the second crown block 7 includes a chamfered portion 20 and a wall surface body 21 extending inward from the chamfered portion 20 in the tire radial direction. The wall surface body 21 includes, for example, a straight portion 22 and an arc-shaped portion 23. The straight portion 22 of the second crown block 7 is formed of a first portion 22A and a second portion 22B. The first portion 22A is formed similarly to the straight portion 22 of the first block wall surface 15 (shown in Figure 3(a)). Figure 6 is a longitudinal section view of the second portion 22B, which is a cross-sectional view along line CC in Figure 1. As shown in Figure 6, the second portion 22B includes an outer portion 29a connected to the chamfered portion 20, an inner portion 29b connected to the arc-shaped portion 23, and a connecting portion 29c connecting the outer portion 29a and the inner portion 29b. The joint portion 29c is formed with a gentler slope than, for example, the outer portion 29a and the inner portion 29b. In this embodiment, the joint portion 29c is formed parallel to the tread surface 13.

[0035] The first portion 22A is provided, for example, on the block wall surface 14 adjacent to the crown lateral groove 10 and on the block wall surface 14 adjacent to the second crown joint groove 11B. The second portion 22B is provided, for example, only on the block wall surface 14 adjacent to the second crown joint groove 11B.

[0036] In a plan view of the tread, the total area of ​​the chamfered portion 20 is preferably 1% or more, more preferably 2% or more, more preferably 5% or less, and more preferably 4% or less of the total area of ​​the tread surfaces 13 of the multiple crown blocks 5. This effectively maintains wear resistance.

[0037] Figure 7 is a plan view of the tread portion 2 located axially outward from the first shoulder circumferential groove 3. As shown in Figure 7, the tread portion 2 includes a plurality of shoulder blocks 41 arranged axially outward from the first shoulder circumferential groove 3, and a plurality of shoulder grooves 42 that separate the plurality of shoulder blocks 41. The shoulder grooves 42 extend outward from the first shoulder circumferential groove 3 in the axial direction of the tire.

[0038] Each of the multiple shoulder blocks 41 includes a tread surface 43 and a shoulder block wall surface 44 extending inward from the tread surface 43 in the radial direction of the tire. The shoulder block wall surface 44 includes a third block wall surface 45 adjacent to the shoulder groove 42 and a fourth block wall surface 46 adjacent to the first shoulder circumferential groove 3.

[0039] The third block wall surface 45 does not have a chamfered portion formed on the tread surface 43 side, for example. Also, in this embodiment, the fourth block wall surface 46 does not have a chamfered portion formed on the tread surface 43 side. This further improves snow performance. The third block wall surface 45 and the fourth block wall surface 46 are formed of a wall surface body 21 that includes a straight portion 22 and an arc-shaped portion 23, for example, similar to the second block wall surface 16 (as shown in Figure 3(b)). In this embodiment, the third block wall surface 45 and the fourth block wall surface 46 are formed of the wall surface body 21 only.

[0040] The shoulder groove 42 includes, for example, a shoulder lateral groove 42A that extends from the first shoulder circumferential groove 3 to the first tread edge T1 and is arranged in the circumferential direction of the tire, and a shoulder longitudinal groove 42B that extends in the circumferential direction of the tire, connecting adjacent shoulder lateral grooves 42A in the circumferential direction of the tire. The shoulder longitudinal groove 42B extends, for example, along the first tread edge T1.

[0041] The third block wall surface 45 includes a third horizontal block wall surface 45A adjacent to the shoulder horizontal groove portion 42A and a third vertical block wall surface 45B facing the shoulder vertical groove portion 42B.

[0042] The shoulder block wall surface 44 includes a notch 48 that is recessed toward the inside of the tread surface 43. Figure 8 is a cross-sectional view taken along line DD of Figure 7. As shown in Figure 8, the notch 48 is provided, for example, in the wall surface body 21. In this embodiment, the wall surface body 21 includes the notch 48, a straight section 22, and an arc-shaped section 23. The notch 48 includes, for example, a transverse surface 48a that extends inward from the tread surface 43 in the radial direction of the tire and faces toward the center of the groove, and an outward surface 48b that is connected to the transverse surface 48a and faces outward in the radial direction of the tire. Such a notch 48 increases the volume of snow to be sheared, further improving snow performance. The outward surface 48b is connected, for example, to the straight section 22.

[0043] The notches 48 are provided, for example, on the third horizontal block wall surface 45A. For example, one notch 48 is provided on each third horizontal block wall surface 45A. The notches 48 are also provided, for example, on the fourth block wall surface 46. In this embodiment, the notches 48 are not provided on the third vertical block wall surface 45B.

[0044] In a plan view of the tread, the total area of ​​the notches 48 is preferably 1% or more of the total area of ​​the tread surface 43 of the shoulder blocks 41, more preferably 2% or more, more preferably 5% or less, and more preferably 4% or less. Since the total area of ​​the notches 48 is 1% or more of the total area of ​​the tread surface 43 of the shoulder blocks 41, snow performance is improved when the outer shape of the shoulder blocks 41 is kept the same. Since the total area of ​​the notches 48 is 5% or less of the total area of ​​the tread surface 43 of the shoulder blocks 41, wear resistance is maintained when the outer shape of the shoulder blocks 41 is kept the same.

[0045] The depth D1 of the notch 48 is preferably 10% or more of the height Hb of the shoulder block 41 in the tire radial direction, more preferably 20% or more, more preferably 50% or less, and more preferably 40% or less. This further improves snow performance while maintaining wear resistance.

[0046] In this embodiment, the shoulder block 41 includes a first shoulder block 41A and a second shoulder block 41B which has a shorter length in the tire axial direction than the first shoulder block 41A. The first shoulder block 41A is divided by a pair of shoulder lateral grooves 42A, a first tread end T1, and a first shoulder circumferential groove 3. The second shoulder block 41B is divided by a pair of shoulder lateral grooves 42A, a shoulder longitudinal groove 42B, and a first shoulder circumferential groove 3. The outer end 41e of the second shoulder block 41B in the tire axial direction is located inward from the first tread end T1 in the tire axial direction.

[0047] The shoulder block 41 of this embodiment is provided with a shoulder sipe 50. The shoulder sipe 50 includes a first shoulder sipe 50A provided on the first shoulder block 41A and a second shoulder sipe 50B provided on the second shoulder block 41B. The first shoulder sipe 50A has, for example, an outer end 51a in the tire axial direction that terminates inward from the first tread end T1 in the tire axial direction. The second shoulder sipe 50B has, for example, an outer end 51b in the tire axial direction that terminates on the tread surface 43 without connecting to the shoulder longitudinal groove 42B.

[0048] Figure 9 is a plan view of the tread portion 2 of another embodiment. Components identical to those in this embodiment are denoted by the same reference numerals and their descriptions are omitted. As shown in Figure 9, in this embodiment, the tread portion 2 has a chamfered portion 20 formed on the tread surface 13 side of the second block wall surface 16 in a range of 35% to 45% of the length L2 of the second block wall surface 16 measured along the tread surface 13. Even in such a tire 1, snow performance is further improved while wear resistance is maintained.

[0049] Although particularly preferred embodiments of this disclosure have been described in detail above, this disclosure is not limited to the illustrated embodiments and can be implemented in various modified forms.

[0050] [Note] This disclosure includes the following aspects.

[0051] [Disclosure 1] A tire having a tread portion, The aforementioned tread portion is The first tread end and Displaced between the first tread end and the tire equator, and adjacent to the first tread end, Multiple crown blocks are arranged on the tire axial side of the first shoulder circumferential groove, The first shoulder circumferential groove is positioned on the tire axial side and includes a plurality of crown grooves that separate the plurality of crown blocks, The plurality of crown blocks include a plurality of first crown blocks adjacent to the first shoulder circumferential groove, Each of the plurality of first crown blocks includes a tread surface and a block wall surface extending inward from the tread surface in the radial direction of the tire, The block wall surface includes a first block wall surface adjacent to the crown groove and a second block wall surface adjacent to the first shoulder circumferential groove. The first block wall surface has a chamfered portion formed on the tread side over a range of 50% or more of the length of the first block wall surface measured along the tread surface. The second block wall surface either does not have a chamfered portion formed on the tread side, or a chamfered portion is formed on the tread side in an area of ​​less than 50% of the length of the second block wall surface measured along the tread. tire. [Disclosure 2] The tire according to Disclosure 1, wherein the first block wall surface has the chamfered portion formed over 100% of the length of the first block wall surface. [Disclosure 3] The first block wall includes a wall body extending inward from the chamfered portion in the tire radial direction, The tire according to disclosure 1 or 2, wherein the difference (θ1-θ2) between the angle θ1 of the chamfered portion with respect to the normal of the tread surface and the angle θ2 of the wall surface body with respect to the normal is 10 to 30 degrees. [Disclosure 4] The tire according to any one of disclosures 1 to 3, wherein the length of the chamfered portion in the tire radial direction is 20% to 40% of the length of the block wall surface in the tire radial direction. [Disclosure 5] The tire according to any one of disclosures 1 to 4, wherein the angle θ1 of the chamfered portion with respect to the normal of the tread surface is 10 to 30 degrees. [Disclosure 6] The tread portion includes a plurality of shoulder blocks arranged on the tire axial side of the first shoulder circumferential groove, and a plurality of shoulder grooves extending outward from the first shoulder circumferential groove in the tire axial direction and separating the plurality of shoulder blocks. Each of the aforementioned multiple shoulder blocks includes a tread surface and a shoulder block wall surface extending inward from the tread surface in the radial direction of the tire. The shoulder block wall surface includes a third block wall surface adjacent to the shoulder groove and a fourth block wall surface adjacent to the first shoulder circumferential groove. The tire according to any one of disclosures 1 to 6, wherein the third block wall surface does not have a chamfered portion formed on the tread side. [Disclosure 7] The tire according to disclosure 6, wherein the fourth block wall surface does not have a chamfered portion formed on the tread side. [Disclosure 8] The shoulder block wall surface includes a notch that is recessed toward the inside of the tread surface, The tire according to disclosure 6 or 7, wherein the depth of the notch is 10% to 50% of the height of the shoulder block in the tire radial direction. [Disclosure 9] The tire according to disclosure 8, wherein, in a plan view of the tread, the total area of ​​the notches is 1% to 5% of the total area of ​​the tread surfaces of the plurality of shoulder blocks. [Disclosure 10] The plurality of crown blocks include a plurality of second crown blocks arranged on the tire axial side of the first crown block, Each of the plurality of second crown blocks includes a tread surface and a block wall surface extending inward from the tread surface in the radial direction of the tire. The tire according to any one of disclosures 1 to 9, wherein the block walls of the plurality of second crown blocks have chamfered portions formed on the tread side over a range of 50% or more of the length of the block wall measured along the tread. [Disclosure 11] The tire according to disclosure 10, wherein, in a plan view of the tread, the total area of ​​the chamfered portion is 1% to 5% of the total area of ​​the tread surfaces of the plurality of crown blocks. [Explanation of Symbols]

[0052] 1 tire 3. First shoulder circumferential groove 6. First Crown Block 9 Crown groove 13 Tread 14 Block wall 15. Wall of Block 1 16. Wall of Block 2 20 Chamfered section L1 Length of the first block wall L2 Length of the wall surface of the second block

Claims

1. A tire having a tread portion, The aforementioned tread portion is The first tread end and Displaced between the first tread end and the tire equator, and adjacent to the first tread end, Multiple crown blocks arranged on the tire axial side of the first shoulder circumferential groove, The first shoulder circumferential groove is arranged on the tire axial side and includes a plurality of crown grooves that separate the plurality of crown blocks, The plurality of crown blocks include a plurality of first crown blocks adjacent to the first shoulder circumferential groove, Each of the plurality of first crown blocks includes a tread surface and a block wall surface extending inward from the tread surface in the radial direction of the tire. The block wall surface includes a first block wall surface adjacent to the crown groove and a second block wall surface adjacent to the first shoulder circumferential groove. The first block wall surface has a chamfered portion formed on the tread side over a range of 50% or more of the length of the first block wall surface measured along the tread surface. The second block wall surface either does not have a chamfered portion formed on the tread side, or a chamfered portion is formed on the tread side in an area of ​​less than 50% of the length of the second block wall surface measured along the tread. The tread portion includes a plurality of shoulder blocks arranged on the tire axial side of the first shoulder circumferential groove, and a plurality of shoulder grooves extending outward from the first shoulder circumferential groove in the tire axial direction and separating the plurality of shoulder blocks. Each of the aforementioned multiple shoulder blocks includes a tread surface and a shoulder block wall surface extending inward from the tread surface in the radial direction of the tire. The shoulder block wall surface includes a third block wall surface adjacent to the shoulder groove and a fourth block wall surface adjacent to the first shoulder circumferential groove. The fourth block wall surface does not have a chamfered portion formed on the tread side. tire.

2. The tire according to claim 1, wherein the chamfered portion is formed on the first block wall surface over a range of 100% of the length of the first block wall surface.

3. The first block wall includes a wall body extending inward from the chamfered portion in the tire radial direction, The tire according to claim 1 or 2, wherein the difference (θ1 - θ2) between the angle θ1 of the chamfered portion with respect to the normal of the tread surface and the angle θ2 of the wall surface body with respect to the normal is 10 to 30 degrees.

4. The tire according to any one of claims 1 to 3, wherein the length of the chamfered portion in the tire radial direction is 20% to 40% of the length of the block wall surface in the tire radial direction.

5. The tire according to any one of claims 1 to 4, wherein the angle θ1 of the chamfered portion with respect to the normal of the tread surface is 10 to 30 degrees.

6. The tire according to any one of claims 1 to 5, wherein the third block wall surface does not have a chamfered portion formed on the tread side.

7. The shoulder block wall surface includes a notch that is recessed toward the inside of the tread surface, The tire according to any one of claims 1 to 6, wherein the depth of the notch is 10% to 50% of the height of the shoulder block in the tire radial direction.

8. The tire according to claim 7, wherein, in a plan view of the tread, the total area of ​​the notches is 1% to 5% of the total area of ​​the tread surfaces of the plurality of shoulder blocks.

9. The plurality of crown blocks include a plurality of second crown blocks arranged inward from the tire axial direction of the first crown block, Each of the aforementioned plurality of second crown blocks includes a tread surface and a block wall surface extending inward from the tread surface in the radial direction of the tire, The tire according to any one of claims 1 to 8, wherein the block wall surfaces of the plurality of second crown blocks have chamfered portions formed on the tread side over a range of 50% or more of the length of the block wall surface measured along the tread.

10. The tire according to claim 9, wherein in a plan view of the tread, the total area of ​​the chamfered portion is 1% to 5% of the total area of ​​the tread surfaces of the plurality of crown blocks.

Images