Tire

Abstract

To improve on-snow and ice performance and maintain high anti-chip performance and mold releasing performance.SOLUTION: A tire 1 includes two or more sipe pairs 5 formed so that an interval between adjacent sipes 4 becomes smaller than an interval between other adjacent sipes 4. In at least one of the sipe pairs 5, each of the sipes 4 includes: a body part 6; and an expanded width part 7 disposed on a tire radial inside from the body part 6 and having a width larger than that of the body part 6. Each of the expanded width parts 7 has a width expanded in a direction separating from each other.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a tire.

Background Art

[0002] Patent Document 1 below describes a pneumatic tire provided with a pair of sipings in a block. Each of the sipings has a constant-width portion extending inward in the tire radial direction and a widened portion extending inward in the tire radial direction from the constant-width portion and having a gradually increasing siped width. Such a siping having a widened portion is said to relieve stress concentration at the bottom of the siping and suppress cracks.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, with respect to improving performance on ice and snow, there was still room for further improvement in the above-described tire. Further, in order to improve ice performance, increasing the number of sipings per block caused a significant decrease in the rigidity of the block, resulting in problems such as chipping at the bottom of the sipes or difficulty in removing the vulcanization mold.

[0005] The present disclosure has been devised in view of the above problems, and the main object thereof is to provide a tire that can improve performance on ice and snow and maintain high chipping resistance performance and mold release performance.

Means for Solving the Problems

[0006] The present disclosure relates to a tire having a tread portion, wherein a plurality of blocks are provided in the tread portion, and a plurality of sipes are provided in at least one of the plurality of blocks. The plurality of sipes have two or more sipe pairs formed such that the interval between adjacent sipes is smaller than the interval between other adjacent sipes. In at least one of the sipe pairs, each of the sipes includes a main body portion and a widened portion that is disposed radially inward of the main body portion with respect to the tire radius and has a width larger than that of the main body portion, and each of the widened portions widens only in a direction away from each other.

Advantages of the Invention

[0007] By adopting the above configuration, the tire of the present disclosure can improve the performance on ice and snow and maintain high cut resistance performance and mold release performance.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0009] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. FIG. 1 is an enlarged plan view conceptually explaining a part of a tread portion 2 of a tire 1 of the present disclosure. The present disclosure is applied to, for example, a pneumatic tire for heavy loads that can also be driven in winter. However, the present disclosure may be applied to, for example, a tire 1 for a passenger car or a light truck.

[0010] In the tread portion 2 of the present embodiment, a plurality of blocks 3 are provided. In the present embodiment, the plurality of blocks 3 are arranged in the tire circumferential direction and in the tire circumferential direction.

[0011] At least one of the plurality of blocks 3 is provided with a plurality of sipes 4. The sipes 4 apply a scraping force to the ice and snow road surface and improve the performance on ice and snow. In addition, the plurality of sipes 4 have two or more sipe pairs 5 formed by adjacent sipes 4, 4. Thereby, the performance on ice and snow is improved. Such a sipe 4 is formed, for example, by a thin blade-like knife blade provided in a vulcanization mold having a well-known structure (not shown).

[0012] FIG. 2 is a cross-sectional view taken along line A-A of FIG. 1. As shown in FIG. 2, in at least one of the sipe pairs 5, each of the sipes 4 includes a main body portion 6 and a widened portion 7 disposed inside the main body portion 6 in the tire radial direction and having a width larger than that of the main body portion 6. The widened portion 7 suppresses stress concentration at the bottom side of the sipe 4 and prevents the occurrence of chipping and cracks (hereinafter referred to as "chipping or the like"). In this embodiment, each of the sipes 4 of the two sipe pairs 5 is formed to include the main body portion 6 and the widened portion 7.

[0013] Each of the widened portions 7 of the sipe pair 5 widens only in a direction away from each other. Thereby, in the portion with relatively low block rigidity sandwiched between the sipes 4 of the sipe pair 5, the shearing force due to the pulling out of the vulcanization mold becomes small, so that the chipping resistance performance and the mold release performance are maintained at a high level.

[0014] The sipe 4 of the sipe pair 5 is formed such that the interval La between adjacent sipes 4 is smaller than the interval Lb between other adjacent sipes 4. As a result, the block rigidity becomes relatively large between the sipe 4 of the sipe pair 5 and other sipes 4. For this reason, the chipping resistance performance and the mold release performance are maintained at a high level even between the sipe 4 of the sipe pair 5 and other sipes 4. Although not particularly limited, the interval La between adjacent sipes 4 of the sipe pair 5 is desirably 3.5 mm or more, more desirably 4 mm or more, desirably 7 mm or less, and more desirably 6 mm or less.

[0015] In this specification, a sipe refers to a notch-shaped recess having a sipe width of less than 2.5 mm, and is clearly distinguished from a groove including a main groove or a lateral groove having a width of 2.5 mm or more.

[0016] FIG. 3 is an overall plan view of the tread portion 2 of the present embodiment. As shown in FIG. 3, in the present embodiment, the tread portion 2 includes a pair of crown main grooves 21, 21 arranged with the tire equator C interposed therebetween, and a pair of shoulder main grooves 22, 22 arranged outside thereof in the tire axial direction. Accordingly, in the present embodiment, the tread portion 2 is divided into a crown land portion 25, a pair of middle land portions 26, 26, and a pair of shoulder land portions 27, 27. The crown land portion 25 of the present embodiment is arranged between the pair of crown main grooves 21, 21. The middle land portion 26 of the present embodiment is arranged between the crown main groove 21 and the shoulder main groove 22. The shoulder land portion 27 of the present embodiment is arranged between the shoulder main groove 22 and the tread end Te.

[0017] The "tread end Te" is the most axially outer grounding position when a normal load is applied to a tire 1 in a normal state that is unloaded with a normal rim mounted and filled with a normal internal pressure and is grounded on a plane at a camber angle of 0 degrees. Unless otherwise specified, the dimensions and the like of each part of the tire are values measured in the normal state.

[0018] The "regular rim" is the rim defined for each tire in the standard system including the standards on which the tire is based. For example, 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".

[0019] The "regular internal pressure" is the air pressure defined for each tire in the standard system including the standards on which the tire is based. In the case of JATMA, it is the "maximum air pressure"; in the case of TRA, it is the maximum value described in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES"; and in the case of ETRTO, it is the "INFLATION PRESSURE".

[0020] The "regular load" is the load defined for each tire in the standard system including the standards on which the tire is based. In the case of JATMA, it is the "maximum load capacity"; in the case of TRA, it is the maximum value described in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES"; and in the case of ETRTO, it is the "LOAD CAPACITY".

[0021] The crown land portion 25 of the present embodiment includes crown longitudinal grooves 30 extending in the tire circumferential direction and crown transverse grooves 31 arranged in the tire circumferential direction. The crown longitudinal grooves 30 are arranged at the intermediate position in the tire axial direction of the crown land portion 25. The crown transverse grooves 31 extend from the crown main groove 21 to the crown longitudinal grooves 30. As a result, a plurality of crown blocks 33 defined by the crown main groove 21, the crown longitudinal grooves 30, and the crown transverse grooves 31 adjacent in the tire circumferential direction are formed in the crown land portion 25. The crown blocks 33 are arranged, for example, in the tire circumferential direction and also in the tire axial direction.

[0022] The middle land portion 26 of the present embodiment includes a middle longitudinal groove 35 extending in the tire circumferential direction, a first middle transverse groove 36 arranged in the tire circumferential direction, and a second middle transverse groove 37 arranged in the tire circumferential direction. The middle longitudinal groove 35 is disposed, for example, at an intermediate position in the tire axial direction of the middle land portion 26. The first middle transverse groove 36 extends, for example, from the crown main groove 21 to the middle longitudinal groove 35. The second middle transverse groove 37 extends, for example, from the shoulder main groove 22 to the middle longitudinal groove 35. As a result, a plurality of first middle blocks 40 and a plurality of second middle blocks 41 are formed in the middle land portion 26. The first middle block 40 of the present embodiment is defined by the crown main groove 21, the middle longitudinal groove 35, and the first middle transverse groove 36 adjacent in the tire circumferential direction, and is arranged in the tire circumferential direction. The second middle block 41 of the present embodiment is defined by the shoulder main groove 22, the middle longitudinal groove 35, and the second middle transverse groove 37 adjacent in the tire circumferential direction, and is arranged in the tire circumferential direction.

[0023] The shoulder land portion 27 of the present embodiment includes a shoulder longitudinal groove 44 extending in the tire circumferential direction, a first shoulder transverse groove 45 arranged in the tire circumferential direction, and a second shoulder transverse groove 46 arranged in the tire circumferential direction. The shoulder longitudinal groove 44 is disposed, for example, at an intermediate position in the tire axial direction of the shoulder land portion 27. The first shoulder transverse groove 45 extends, for example, from the shoulder main groove 22 to the shoulder longitudinal groove 44. The second shoulder transverse groove 46 extends, for example, from the tread end Te to the shoulder longitudinal groove 44. As a result, a plurality of first shoulder blocks 48 and a plurality of second shoulder blocks 49 are formed in the shoulder land portion 27. The first shoulder block 48 is defined by, for example, the shoulder main groove 22, the shoulder longitudinal groove 44, and the first shoulder transverse groove 45 adjacent in the tire circumferential direction, and is arranged in the tire circumferential direction. The second shoulder block 49 is defined by, for example, the tread end Te, the shoulder longitudinal groove 44, and the second shoulder transverse groove 46 adjacent in the tire circumferential direction, and is arranged in the tire circumferential direction. Note that the shape of the tread portion 2 is not limited to such a mode, and various shapes can be adopted.

[0024] In the crown block 33, the first middle block 40, and the second middle block 41, in this embodiment, three sip pairs 5 are provided respectively. In the first shoulder block 48 of this embodiment, two sip pairs 5 and one sip 4 are provided on both sides in the tire circumferential direction of the two sip pairs 5 respectively. Further, the second shoulder block 49 of this embodiment is provided with two sip pairs 5 and one sip 4 sandwiched between the two sip pairs 5.

[0025] Hereinafter, the sip pair 5 arranged in the first middle block 40 will be described in detail. Also, regarding the sip pair 5 arranged in the block 3 other than the first middle block 40, the parts different from the sip pair 5 arranged in the first middle block 40 will be described.

[0026] FIG. 4 is a cross-sectional view taken along line B-B of FIG. 3, showing a longitudinal section in the sip width direction of the sip 4. As shown in FIG. 4, each sip 4 of the sip pair 5 has a pair of wall surfaces 8, 8 extending radially inward in the tire radius direction from the tread surface 40t of the first middle block 40.

[0027] The pair of wall surfaces 8, 8 includes a first wall surface 8A on the side adjacent to the sips 4 of the sip pair 5 and a second wall surface 8B on the side opposite to the first wall surface 8A. The first wall surface 8A and the second wall surface 8B are connected at the bottom 9. The bottom 9 is, in this embodiment, the innermost end 4i in the tire radius direction of the sip 4. Note that the bottom 9 may be a plane extending in the sip width direction at the innermost side in the tire radius direction of the sip 4 (not shown).

[0028] In this embodiment, the first wall surface 8A includes a first arc portion 10 that extends in an arc shape outward in the tire radial direction from the bottom portion 9. The first wall surface 8A includes, for example, the first arc portion 10 and a first linear portion 12 that extends linearly connected to the first arc portion 10. The first arc portion 10 of this embodiment is formed to be convex toward the outside of the sipe 4. Such a first arc portion 10 effectively relieves stress concentration. The first arc portion 10 is formed of, for example, a single arc with the same radius of curvature. Note that the first arc portion 10 may be formed of a plurality of arcs with different radii of curvature. The first arc portion 10 is formed, for example, without extending toward the sipe 4 side of the adjacent sipe pair 5 more than the first linear portion 12. The first linear portion 12 extends smoothly connected to the first arc portion 10 to the tread surface 40t, for example.

[0029] The second wall surface 8B includes a second arc portion 11 that extends in an arc shape outward in the tire radial direction from the bottom portion 9. The second arc portion 11 of this embodiment is formed to be convex toward the outside of the sipe 4. Such a second arc portion 11 more effectively relieves stress concentration. The second wall surface 8B includes, for example, the second arc portion 11, an inward arc portion 13, a second linear portion 14, and a bulging portion 15. The inward arc portion 13 is, for example, an arc shape that is connected to the second arc portion 11 and is concave toward the inside of the sipe 4. The second linear portion 14 extends linearly outward in the tire radial direction connected to the inward arc portion 13, for example. The bulging portion 15 extends so as to bulge in the same direction as the widening portion 7 in this embodiment, which is a direction to widen the sipe width, by connecting the second linear portion 14 and the tread surface 40t.

[0030] The radius of curvature r1 of the first arc portion 10 is preferably 0.3 to 0.5 mm. Also, the radius of curvature r2 of the second arc portion 11 is preferably 0.5 to 0.8 mm. Thereby, the chipping resistance and the mold release performance are improved. When the first arc portion 10 or the second arc portion 11 is formed of a plurality of radii of curvature, the radii of curvature r1 and r2 are defined by the average of the minimum radius of curvature and the maximum radius of curvature, respectively.

[0031] The widened portion 7 has a maximum half-width Wa from the width center 6c of the main body portion 6. In order to enhance the mold release performance while suppressing chips or the like on the bottom side, the maximum half-width Wa is desirably 1.5 times or more, more desirably 2.0 times or more, desirably 4.0 times or less, and more desirably 3.5 times or less of the half-width Wb of the main body portion 6. Although not particularly limited, the half-width Wb is desirably 0.1 mm or more, more desirably 0.2 mm or more, desirably 0.5 mm or less, and more desirably 0.4 mm or less.

[0032] The bulging portion 15 is formed such that the half-width Wc from the width center 6c of the main body portion 6 is larger than the maximum half-width Wa of the widened portion 7. Such a bulging portion 15 particularly enhances the snow performance. The half-width Wc of the bulging portion 15 is desirably 1.2 times or more, more desirably 1.3 times or more, even more desirably 1.4 times or more, desirably 2.0 times or less, more desirably 1.9 times or less, and even more desirably 1.8 times or less of the maximum half-width Wa.

[0033] FIG. 5 is a plan view of the first middle block 40 of FIG. 3. As shown in FIG. 5, in this embodiment, the first middle block 40 includes a pair of first block edges 40a, 40a and a pair of second block edges 40b, 40b that respectively connect both ends of the pair of first block edges 40a, 40a. Each of the first block edges 40a is spaced apart from the sip 4 of the sip pair 5 in the sip width direction. Each of the second block edges 40b is spaced apart in the longitudinal direction of the sip 4. One of the pair of second block edges 40b is in contact with, for example, the middle longitudinal sip 35. The other of the pair of second block edges 40b is in contact with, for example, the crown main groove 21.

[0034] The distance La between the adjacent sipes 4, 4 of the sipe pair 5 is desirably at least 0.3 times, more desirably at least 0.4 times, desirably at most 0.8 times, and more desirably at most 0.7 times the distance Lb between the other sipes 4. Since the distance La between the sipes 4, 4 is at least 0.3 times the distance Lb between the other sipes 4, a decrease in the block rigidity between the sipes 4, 4 can be suppressed. Since the distance La between the sipes 4, 4 is at most 0.8 times the distance Lb between the other sipes 4, the block rigidity on the side where the widened portion 7 widens can be maintained high, a large opening of the sipe 4 is suppressed, and the chipping resistance performance is improved.

[0035] From the same viewpoint, the distance La between the sipes 4, 4 of the sipe pair 5 is desirably at least 0.3 times, more desirably at least 0.4 times, desirably at most 0.8 times, and more desirably at most 0.7 times the distance Lc between the sipe 4 closest to the first block edge 40a and the first block edge 40a. The distance Lb and the distance Lc are, in this specification, the maximum lengths extending in the longitudinal direction of the sipe 4.

[0036] The sipes 4 of the sipe pair 5 each extend at an angle α of 40 degrees or less with respect to the tire axial direction. Such sipes 4 increase the circumferential scraping force of the tire and improve the performance on ice and snow. The angle α is specified in this specification by a virtual straight line 4n connecting both ends 4e, 4e of the sipe 4 with a straight line.

[0037] FIG. 6 is a cross-sectional view taken along the line C-C of FIG. 5. As shown in FIG. 6, the depth d1 of the sipe 4 of the first middle block 40 is equal to or less than the depth d2 of the middle longitudinal sipe 35. Thereby, since the circumferential rigidity of the first middle block 40 is maintained high, the performance on ice is improved. In addition, the depth d1 of the sipe 4 in the present embodiment is the same as the depth d2 of the middle longitudinal sipe 35. Further, the depth (not shown) of each sipe 4 in the second middle block 41 is desirably equal to or less than the depth d2 of the middle longitudinal sipe 35. In the present embodiment, the depth of each sipe 4 in the second middle block 41 is the same as the depth d2 of the middle longitudinal sipe 35.

[0038] Furthermore, the depth (not shown) of each sip 4 within the crown block 33 is desirably equal to or less than the depth of the crown vertical sip 30. In the present embodiment, the depth of each sip 4 within the crown block 33 is the same as the depth of the crown vertical sip 30. Also, the depth of each sip 4 within the shoulder land portion 27 is desirably equal to or less than the depth of the shoulder vertical sip 44. In the present embodiment, the depth of each sip 4 within the first shoulder block 48 is the same as the depth of the shoulder vertical sip 44. In the present embodiment, the depth of each sip 4 within the second shoulder block 49 is formed to be smaller than the depth of the shoulder vertical sip 44.

[0039] As described above, the tire according to one embodiment of the present disclosure has been described in detail. However, the present disclosure is not limited to the above specific embodiments and can be implemented with various modifications.

Example

[0040] An 11R22.5 pneumatic heavy-duty tire having the basic pattern of FIG. 3 was prototyped based on the specifications in Table 1. Then, the snow performance, ice performance, chipping resistance performance, and mold release performance of each test tire were tested. The common specifications and test methods of each test tire are as follows.

[0041] <Snow performance and ice performance> Using the following test vehicle, the time required to travel 200 m on a test course of a snow road surface and an ice road surface with continuous curves having a radius of curvature of 30 m was measured respectively. The results are shown by an index with the reciprocal of the travel time of Example 1 being 100. The larger the numerical value, the better the snow performance and ice performance. Mounting rim: 7.50×22.5 Tire internal pressure: 800 kPa Test vehicle: 10t truck (2-D vehicle) with a load of 5t Tire mounting position: all wheels In Table 1, "A" indicates a mode in which each widened portion of the sip pair widens only in a direction away from each other. "B" in the same table indicates a mode in which each widened portion widens only in a direction facing each other. "C" is a mode in which each widened portion widens in both directions facing each other and separating from each other.

[0042] <Chipping resistance performance> When the block was worn 40% on the test vehicle, the number of chips and the like starting from the sip was visually measured and evaluated in four grades as follows. The larger the numerical value, the better the chipping resistance performance. 100: No chips or the like have occurred. 95: There are 1 to 5 chips or the like. 90: There are 6 to 10 chips or the like. 85: There are 11 or more chips or the like.

[0043] <Mold release performance> The state between the knife blades of the vulcanizing mold after each test tire was vulcanized and molded was confirmed. The results are evaluated by the sensory evaluation of the examiner's visual inspection and shown in a score with Example 1 as 100. The larger the numerical value, the less rubber remains between the knife blades, indicating better performance. The test results are shown in Table 1. In each test, any example with less than 95 in any one is unqualified, and any example with 95 or more in all of the tests is qualified.

[0044]

Table 1

[0045] As a result of the test, it was confirmed that the tires of the examples exhibited excellent performance on ice and snow. In addition, it was confirmed that the tires of the examples were less likely to have chips or the like and were also excellent in mold release performance.

[0046] [Appendix] This disclosure includes the following aspects.

[0047] [This disclosure 1] A tire having a tread portion, A plurality of blocks are provided on the tread portion, At least one of the plurality of blocks is provided with a plurality of sipes. The plurality of sipes have two or more pairs of sipes formed such that the interval between adjacent sipes is smaller than the interval between other adjacent sipes. In at least one of the pairs of sipes, each of the sipes includes a main body portion and a widened portion that is arranged radially inward of the tire with respect to the main body portion and has a width larger than that of the main body portion. Each of the widened portions widens only in a direction away from each other. Tire. [Disclosure 2] Each of the sipes has a pair of wall surfaces extending radially inward of the tire from the tread surface of the block. The pair of wall surfaces includes a first wall surface on the adjacent side between the sipes of the pair of sipes and a second wall surface on the side opposite to the first wall surface. The first wall surface and the second wall surface are continuous at the bottom. In a longitudinal section in the sipe width direction, the first wall surface includes a first arc portion extending arcuately radially outward of the tire from the bottom. The radius of curvature of the first arc portion is 0.3 to 0.5 mm, the tire according to Disclosure 1. [Disclosure 3] In a longitudinal section in the sipe width direction, the second wall surface includes a second arc portion extending arcuately radially outward of the tire from the bottom. The radius of curvature of the second arc portion is 0.5 to 0.8 mm, the tire according to Disclosure 2. [Disclosure 4] Each of the sipes extends at an angle of 40 degrees or less with respect to the tire axial direction, the tire according to any one of Disclosures 1 to 3. [Disclosure 5] The widened portion has a maximum half-width from the width center of the main body portion. The maximum half-width is 1.5 to 4.0 times the half-width of the main body portion, the tire according to any one of Disclosures 1 to 4. [Disclosure 6] The maximum half-width is 2.0 to 3.5 times the half-width of the main body portion, the tire according to Disclosure 5. [Disclosure 7] The distance between the adjacent sipes of the sipe pair is 0.3 to 0.8 times the distance between other adjacent sipes. The tire according to any one of Disclosures 1 to 6. [Disclosure 8] The block includes a block edge spaced from the sipes of the sipe pair in the sipe width direction. The distance between the adjacent sipes of the sipe pair is 0.3 to 0.8 times the distance between the sipe closest to the block edge and the block edge. The tire according to any one of Disclosures 1 to 7. [Disclosure 9] The block is defined by continuous sipes in which the sipes of each sipe pair are continuous. The depth of each sipe is less than or equal to the depth of the continuous sipe. The tire according to any one of Disclosures 1 to 8. [Disclosure 10] Three or more sipe pairs are provided in the block. The tire according to any one of Disclosures 1 to 9.

Explanation of Reference Numerals

[0048] 1 Tire 4 Sipes 6 Body portion 7 Widening portion

Claims

1. A tire having a tread portion, wherein a plurality of blocks are provided in the tread portion, at least one of the plurality of blocks is provided with a plurality of sipes, the plurality of sipes have two or more sipe pairs formed such that the interval between adjacent sipes is smaller than the interval between other adjacent sipes, in at least one of the sipe pairs, each of the sipes includes a main body portion and a widened portion disposed radially inward of the tire radius direction with respect to the main body portion and having a width larger than that of the main body portion, each of the widened portions widens only in a direction away from each other, the widened portion has a maximum half-width from the width center of the main body portion, each sipe constituting the sipe pair has a pair of wall surfaces extending radially inward from the tread surface of the block, the pair of wall surfaces includes a first wall surface on the adjacent side between the sipes of the sipe pair and a second wall surface on the side opposite to the first wall surface, the first wall surface and the second wall surface are continuous at a bottom portion which is the innermost end in the tire radius direction of the sipe, in a longitudinal section in the sipe width direction, the first wall surface includes a first arc portion continuously extending in an arc shape radially outward from the bottom portion and a first linear portion continuously extending linearly from the first arc portion, the first linear portion is disposed at a position most distant from the width center of the main body portion from the bottom portion to the other sipe side of the sipe pair, the second wall surface includes a second arc portion continuously extending in an arc shape radially outward from the bottom portion to the position where the maximum half-width is reached, the bottom portion is located at the width center of the main body portion, a tire.

2. The tire according to claim 1, wherein the radius of curvature of the first arc portion is 0.3 to 0.5 mm.

3. The tire according to claim 2, wherein the radius of curvature of the second arc portion is 0.5 to 0.8 mm.

4. The tire according to any one of claims 1 to 3, wherein each of the sipes extends at an angle of 40 degrees or less with respect to the tire axial direction.

5. The widened portion has a maximum half-width from the width center of the main body portion, The tire according to any one of claims 1 to 4, wherein the maximum half-width is 1.5 to 4.0 times the half-width of the main body portion.

6. The tire according to claim 5, wherein the maximum half-width is 2.0 to 3.5 times the half-width of the main body portion.

7. The distance between the adjacent sipes of the sipes pair is 0.3 to 0.8 times the distance between other adjacent sipes. The tire according to any one of claims 1 to 6.

8. The block includes a block edge spaced from the sipes of the sipes pair in the sipes width direction. The distance between the adjacent sipes of the sipes pair is 0.3 to 0.8 times the distance between the sipes closest to the block edge and the block edge. The tire according to any one of claims 1 to 7.

9. The block is defined by continuous sipes in which the sipes of each sipes pair are continuous. The depth of each sipe is less than or equal to the depth of the continuous sipe. The tire according to any one of claims 1 to 8.

10. The second wall surface further includes a bulging portion connected to the tread surface. The bulging portion includes a half-width from the width center of the main body portion. The half-width of the bulging portion is 1.2 to 1.9 times the maximum half-width. The tire according to any one of claims 1 to 9.

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