JP7632148B2 - tire - Google Patents

Description

This disclosure relates to tires.

The following Patent Document 1 describes a pneumatic tire that is said to improve wet handling stability while ensuring dry handling stability. The pneumatic tire is provided with a communicating lug groove that extends continuously from a first shoulder land portion across the tire equatorial plane to a second land portion and terminates within the second land portion, and a secondary groove that passes through the terminal end of the communicating lug groove and is spaced apart from a second outermost main groove that is arranged axially outside the second land portion.

JP 2018-79903 A

In recent years, there has been a demand for further improvements in wet performance. At the same time, there is also a need to prevent deterioration in steering stability and resistance to uneven wear.

This disclosure was devised in light of the above-mentioned circumstances, and its main objective is to provide a tire that can improve wet performance while suppressing deterioration of steering stability and uneven wear resistance.

The present disclosure relates to a tire having a tread portion, the tread portion comprising a shoulder land portion divided by a shoulder circumferential groove and a tread edge, the shoulder land portion being divided into a plurality of shoulder block elements by a plurality of shoulder lateral grooves, each of the plurality of shoulder lateral grooves including a first portion extending from the tread edge toward the tire axially inward, a second portion on the shoulder circumferential groove side inclined relative to the first portion, and a communicating portion connecting the first portion and the second portion, such that each of the shoulder block elements includes a convex corner portion that is convex toward the block outer side at the communicating portion, and the block sidewall of the convex corner portion includes a first sidewall extending along the first portion, a second sidewall extending along the second portion, and a triangular third sidewall that spans the first sidewall, the second sidewall, and the block tread surface, and the third sidewall terminates radially outward of the groove bottom of the shoulder lateral groove.

By adopting the above configuration, the tire disclosed herein can improve wet performance while suppressing deterioration of steering stability and uneven wear resistance.

FIG. 2 is an enlarged plan view of a tread portion showing one embodiment of the present disclosure. FIG. 2 is an enlarged view of the vicinity of a shoulder lateral groove in FIG. 1 . FIG. 2 is a perspective view of a convex corner portion of FIG. 1 . FIG. FIG. 5 is a cross-sectional view taken along line AA in FIG. 4. FIG. FIG. FIG.

Hereinafter, one embodiment of the present disclosure will be described with reference to the drawings.
1 is an enlarged plan view of a tread portion 2 of a tire 1 according to the present embodiment. The tire 1 according to the present embodiment is suitable for use as a pneumatic tire for winter or all seasons, for example, for commercial vehicles or small trucks. However, the present disclosure can be used for pneumatic tires for heavy loads or passenger cars, or non-pneumatic tires that are not filled with compressed air.

As shown in FIG. 1, the tread portion 2 of this embodiment has a shoulder land portion 5 that is divided by a shoulder circumferential groove 3 and a tread end Te. The shoulder land portion 5 is an area where a relatively large lateral force acts during cornering, and is a land portion that has a large impact on steering stability, uneven wear resistance, and wet performance. This disclosure focuses on such a shoulder land portion 5 and aims to improve the above-mentioned performance.

The tread end Te is the axially outermost contact point when the tire 1 is mounted on a standard rim (not shown), filled to standard internal pressure, and unloaded, and is placed on a flat surface with a standard load and a camber angle of 0°. Unless otherwise specified, the dimensions of each part of the tire 1 are values measured in the standard state. The axial distance between the tread ends Te on both sides of the tire is the tread width TW (shown in Figure 4).

The "regular rim" is a rim that is defined for each tire 1 by the standard system that includes the standard on which tire 1 is based, such as a "standard rim" for JATMA, a "design rim" for TRA, and a "measuring rim" for ETRTO.

The "normal internal pressure" is the air pressure set for each tire 1 by each standard in the standard system including the standard on which tire 1 is based, and is the "maximum air pressure" for JATMA, the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" for TRA, and the "INFLATION PRESSURE" for ETRTO.

The "normal load" is the load that is determined for each tire 1 by each standard in the system of standards, including the standard on which tire 1 is based. In the case of JATMA, it is the "maximum load capacity." In the case of TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES." In the case of ETRTO, it is the "LOAD CAPACITY."

The shoulder land portion 5 has multiple shoulder lateral grooves 7. As a result, the shoulder land portion 5 in this embodiment is divided into multiple shoulder block elements 5a.

Each of the shoulder lateral grooves 7 includes a first portion 11 extending axially inward from the tread edge Te, a second portion 12 on the shoulder circumferential groove 3 side inclined relative to the first portion 11, and a connecting portion 13 connecting the first portion 11 and the second portion 12. Such shoulder lateral grooves 7 provide multi-directional edge components, improving wet performance. The shoulder block element 5a of this embodiment includes a convex corner portion 15 that is convex toward the outside of the block at the connecting portion 13.

Figure 2 is an enlarged view of the vicinity of the shoulder lateral groove 7 in Figure 1. Figure 3 is a perspective view of the convex corner portion 15. As shown in Figures 2 and 3, the block side wall 8 (first lateral side wall 8a described later) of the convex corner portion 15 includes a first side wall 17, a second side wall 18, and a third side wall 19. The first side wall 17 extends along the first portion 11. The second side wall 18 extends along the second portion 12. The third side wall 19 is triangular across the first side wall 17, the second side wall 18, and the block tread surface 9. Such a third side wall 19 increases the groove volume in the communication portion 13, smooths the drainage in the communication portion 13, which has a large drainage resistance, and enhances the drainage action. Therefore, wet performance is improved.

The third side wall 19 terminates radially outward of the groove bottom 7s of the shoulder lateral groove 7. This prevents the stiffness of the shoulder block element 5a from decreasing, and prevents deterioration of steering stability and uneven wear resistance.

Figure 4 is a plan view of the tread portion 2. As shown in Figure 4, the tread portion 2 of this embodiment is provided with two shoulder circumferential grooves 3 and one middle circumferential groove 4 arranged between the shoulder circumferential grooves 3, 3. As a result, the tread portion 2 includes, for example, a pair of shoulder land portions 5 and a pair of middle land portions 6 divided between each of the shoulder circumferential grooves 3 and the middle circumferential groove 4. Note that the tread portion 2 is not limited to this form, and may have a pair of shoulder land portions, a pair of middle land portions, and a crown land portion (not shown) divided into two middle circumferential grooves by two shoulder circumferential grooves and two middle circumferential grooves.

In this embodiment, the shoulder circumferential groove 3 extends continuously in the tire circumferential direction. For example, the shoulder circumferential groove 3 extends in a straight line along the tire circumferential direction. Such a shoulder circumferential groove 3 improves drainage performance.

In this embodiment, the middle circumferential groove 4 extends continuously in the tire circumferential direction. For example, the middle circumferential groove 4 extends in a straight line along the tire circumferential direction. This further improves drainage performance. In this embodiment, the middle circumferential groove 4 is disposed on the tire equator C. Note that the middle circumferential groove 4 and the shoulder circumferential groove 3 are not limited to this form, and may each extend in a zigzag or wavy form.

It is desirable that the groove width W2 of the middle circumferential groove 4 is larger than the groove width W1 of the shoulder circumferential groove 3. This ensures high drainage on the tire equator C side where drainage is difficult. Although not particularly limited, the groove width W2 of the middle circumferential groove 4 is desirably 1.05 times or more, more desirably 1.10 times or more, more desirably 1.30 times or less, and even more desirably 1.25 times or less of the groove width W1 of the shoulder circumferential groove 3. For example, the groove width W1 of the shoulder circumferential groove 3 is desirably 5.0% or more of the tread width TW, more desirably 6.0% or more, preferably 11.0% or less, and even more desirably 10.0% or less.

Figure 5 is an enlarged plan view of the tread portion 2 including the shoulder land portion 5. As shown in Figure 5, in this embodiment, the block sidewall 8 is composed of a surface extending in the tire radial direction so as to form the groove wall of each groove. The block sidewall 8 is connected to, for example, a block tread surface 9 that comes into contact with the road surface.

In this embodiment, the block sidewall 8 includes a first lateral sidewall 8a that forms the convex corner portion 15, a second lateral sidewall 8b that faces the first lateral sidewall 8a, and a first vertical sidewall 8c that forms the shoulder circumferential groove 3. The first lateral sidewall 8a and the second lateral sidewall 8b form the shoulder lateral groove 7. The first lateral sidewall 8a includes a first sidewall 17, a second sidewall 18, and a third sidewall 19.

A buttress region B is provided on the axially outer side of the tread end Te. The buttress region B is a region that does not come into contact with the ground when the tire 1 in a normal state is placed on a flat surface with a normal load and a camber angle of 0°.

In this embodiment, the first portion 11 of the shoulder lateral groove 7 extends in a straight line. Such a first portion 11 maintains high rigidity of the shoulder land portion 5. For example, the first portion 11 extends from the shoulder land portion 5 axially outward of the tread edge Te, in other words, to the buttress region B.

The angle α1 of the first portion 11 relative to the tire axial direction is preferably 20 degrees or less. This allows for greater traction on wet road surfaces. The angle α1 and the angle α2, which will be described later, are determined by the groove center line 7c of the shoulder lateral groove 7. In this embodiment, the angle α1 of the first portion 11 is 0 degrees in the buttress region B.

The second portion 12 extends, for example, in an arc shape in a plan view of the tread. Such a second portion 12 can distribute the load caused by contact with the ground, which helps to suppress deformation of the shoulder lateral grooves 7 and maintain a high groove volume. The angle α2 of the second portion 12 with respect to the tire axial direction continuously decreases toward the outside in the tire axial direction.

The second portion 12 extends from the shoulder circumferential groove 3. In other words, the shoulder lateral groove 7 crosses the shoulder land portion 5. Such a shoulder lateral groove 7 has high drainage properties and improves wet performance. In this embodiment, the shoulder block element 5a is formed as a shoulder block 5R that is divided by the shoulder lateral grooves 7, 7 adjacent in the tire circumferential direction. Note that the shoulder lateral groove 7 is not limited to this form, and for example, the inner end (not shown) in the tire axial direction may terminate within the shoulder land portion 5.

The second portion 12 is inclined at a larger angle relative to the tire axial direction than the first portion 11. Such a second portion 12 increases the length (groove volume) of the shoulder lateral groove 7, and can effectively drain the water film between the tread surface of the shoulder land portion 5 (same as the block tread surface 9) and the road surface.

The angle θ1 between the second portion 12 and the shoulder circumferential groove 3 is preferably 30 degrees or more, more preferably 35 degrees or more, more preferably 50 degrees or less, and even more preferably 45 degrees or less. Since the angle θ1 is 30 degrees or more, the decrease in rigidity of the shoulder land portion 5 adjacent to the second portion 12 is suppressed. In addition, water in the second portion 12 is smoothly discharged to the shoulder circumferential groove 3. Since the angle θ1 is 50 degrees or less, deformation of the shoulder land portion 5 at the time of contact with the ground is suppressed, and the groove width of the second portion 12 is secured. This improves wet performance. In this specification, the angle θ1 is the angle between the first vertical sidewall 8c and the second horizontal sidewall 8b at a position 10 mm away from the first vertical sidewall 8c toward the outside in the tire axial direction.

Figure 6 is a cross-sectional view of line A-A in Figure 4. As shown in Figures 5 and 6, it is desirable that the groove width Wa at the groove bottom 12s of the second portion 12 is constant over the entire length of the second portion 12. Such a second portion 12 increases the rigidity of the axially inner portion of the shoulder land portion 5, suppressing deterioration of steering stability. In this specification, the groove width Wa at the groove bottom 12s is the distance between the inner ends in the tire radial direction of the first lateral side wall 8a and the second lateral side wall 8b that form the shoulder lateral groove 7. The inner ends are formed in an arc portion 8r that is convex outward from the shoulder lateral groove 7 and has a minimum radius of curvature.

Figure 7 is a plan view of the vicinity of the shoulder land portion 5. As shown in Figure 7, the groove width W3 of the first portion 11 is preferably larger than the groove width W4 of the second portion 12. This allows water in the shoulder circumferential groove 3 and the second portion 12 to be easily discharged to the outside of the tread edge Te, improving wet performance. Although not particularly limited, the groove width W3 of the first portion 11 is preferably 3 mm or more, more preferably 4 mm or more, and more preferably 7 mm or less, and more preferably 6 mm or less. The groove width W4 of the second portion 12 is preferably 2.0 to 3.0 mm. The groove width W3 of the first portion 11 is the groove width in the shoulder land portion 5.

The groove depth (not shown) of the first portion 11 is preferably equal to the groove depth d2 of the second portion 12 (shown in FIG. 6).
The groove depth of the first portion 11 is preferably 90% or more, more preferably 95% or more, and is preferably 110% or less, and further preferably 105% or less of the groove depth d2 of the second portion 12. The groove depth of the first portion 11 is the depth at the shoulder land portion.

The communication portion 13 is disposed axially outboard of the axial middle 5c of the shoulder land portion 5. This ensures the length of the second portion 12 having a relatively large angle α2, so that the drainage effect utilizing the rolling motion of the tire 1 is effectively exerted. To further effectively exert the above-mentioned effect, the axial distance La between the communication portion 13 and the tread end Te is preferably 3 mm or more, more preferably 4 mm or more, more preferably 7 mm or less, and even more preferably 6 mm or less. More specifically, the distance La is the axial distance between the connection portion 29 described later and the tread end Te.

3, in this embodiment, the third side wall 19 includes a tread side edge 21 that is the boundary with the block tread 9, a first edge 22 that is the boundary with the first side wall 17, and a second edge 23 that is the boundary with the second side wall 18. Each of the first edge 22 and the second edge 23 is inclined inward in the tire radial direction toward a connection portion 29 between the first edge 22 and the second edge 23. In this embodiment, the connection portion 29 is included in the communication portion 13. The connection portion 29 forms, for example, a bend between the first edge 22 and the second edge 23. The connection portion 29 in this embodiment divides the first portion 11 and the second portion 12.

The tread side edge 21 is formed longer than the first edge 22 and the second edge 23. Such a tread side edge 21 further suppresses the decrease in rigidity of the convex corner portion 15.

As shown in FIG. 2, the length L1 of the tread side edge 21 is greater than the shortest length L2 between the connection portion 29 and the tread side edge 21 in a plan view of the tread. Such a third side wall 19 further suppresses the decrease in rigidity of the convex corner portion 15.

Although not particularly limited, the length L1 of the tread side edge 21 is preferably 25% of the axial width Ws of the shoulder land portion 5, more preferably 30% or more, more preferably 45% or less, and even more preferably 40% or less. The minimum length L2 is preferably 3 mm or more, more preferably 4 mm or more, more preferably 7 mm or less, and even more preferably 6 mm or less.

The third side wall 19 is connected to the tread end Te, for example. Such a third side wall 19 maintains high rigidity of the shoulder block element 5a at the tread end Te where a larger lateral force acts, improving uneven wear resistance and drainage performance. In this embodiment, the connection portion 27 between the tread side edge 21 and the first edge 22 is located on the tread end Te. Note that the connection portion 27 is not limited to this position, and may be located, for example, within a range of 5% of the width Ws of the shoulder land portion 5 inside and outside the tread end Te in the tire axial direction.

The connection portion 29 is preferably located within a range of 30% to 50% of the maximum groove depth d (shown in FIG. 3) of the shoulder lateral groove 7 from the block tread surface 9. This allows for smooth drainage in the shoulder lateral groove 7 and prevents a decrease in the rigidity of the shoulder land portion 5, thereby improving wet performance while preventing deterioration of steering stability and uneven wear resistance. To achieve this effect more effectively, it is even more preferable for the connection portion 29 to be located within a range of 35% to 45% of the maximum groove depth d from the block tread surface 9.

As shown in FIG. 7, in a plan view of the tread, the second lateral sidewall 8b is formed in a convex arc shape toward the inside of the block, continuously from the shoulder circumferential groove 3 to the tread end Te. Such a second lateral sidewall 8b suppresses a decrease in the rigidity of the shoulder land portion 5 and smooths the flow of water in the shoulder lateral groove 7. The angle of the second lateral sidewall 8b with respect to the tire axial direction decreases continuously from the shoulder circumferential groove 3 to the tread end Te.

Figure 8 is a plan view of the vicinity of the shoulder land portion 5. As shown in Figure 8, in this embodiment, the shoulder land portion 5 further includes a shoulder inclined sipe 31, a shoulder longitudinal sipe 32, and a shoulder lateral sipe 33. In this specification, "sipe" means a notch-like body with a width of less than 1.5 mm. In addition, in this specification, "groove", which includes a circumferential groove, a lateral groove, and a lug groove, means a groove-like body with a groove width of 1.5 mm or more.

In this embodiment, the shoulder inclined sipes 31 extend from the shoulder circumferential groove 3 toward the outside in the tire axial direction and terminate within the shoulder block 5R. The shoulder inclined sipes 31 extend, for example, parallel to the second portions 12 of the shoulder lateral grooves 7. Such shoulder inclined sipes 31 improve wet performance.

In this embodiment, the shoulder vertical sipe 32 is formed to include a main portion 34 extending parallel to the tire circumferential direction in the shoulder land portion 5, and a pair of sub-portions 35, 35 that are connected to both ends of the main portion 34 and extend away from the main portion 34 in the tire circumferential direction. In this embodiment, the sub-portion 35 terminates within the shoulder block 5R without exceeding the tread end Te. Such a shoulder vertical sipe 32 reduces only the circumferential rigidity of the shoulder land portion 5, thereby reducing the self-aligning torque power (SATP). This increases the equivalent cornering power (equivalent CP) of the entire tire, and further suppresses the deterioration of the steering stability performance. The equivalent CP is a value obtained by dividing the cornering power by the SATP. The SATP is the self-aligning torque (SAT) when a slip angle of 1 degree is applied to the tire 1 during running. Furthermore, the SAT is expressed as the sum of the braking force and the driving force on the tire circumferential line of the tread contact surface. In this specification, "parallel to the tire circumferential direction" includes cases where the angle with respect to the tire circumferential direction is 0 degrees, as well as cases where the angle is 20 degrees or less.

The circumferential length L3 of the shoulder longitudinal sipes 32 is preferably 50% or more of the circumferential distance L4 between the circumferentially adjacent shoulder lateral grooves 7, 7. This allows the above-mentioned effects to be effectively achieved. More specifically, the length L3 of the shoulder longitudinal sipes 32 is preferably 55% or more of the distance L4 between the shoulder lateral grooves 7, 7, more preferably 60% or more, more preferably 75% or less, and even more preferably 70% or less. This prevents a decrease in the axial stiffness of the shoulder land portion 5, and more adequately maintains steering stability.

In addition, the shortest distance L5 in the tire axial direction between the shoulder vertical sipe 32 and the shoulder inclined sipe 31 is preferably 10% or more of the width Ws of the shoulder land portion 5, more preferably 15% or more, more preferably 30% or less, and even more preferably 25% or less.

In this embodiment, the shoulder lateral sipes 33 extend from the shoulder longitudinal sipes 32 toward the outside in the tire axial direction. For example, the shoulder lateral sipes 33 extend from the shoulder land portion 5 beyond the tread edge Te to the buttress region B. In this embodiment, the shoulder lateral sipes 33 extend along the tire axial direction. For example, two shoulder lateral sipes 33 are connected to the shoulder longitudinal sipes 32. In this embodiment, the shoulder lateral sipes 33 are connected to the connection position between the main portion 34 and the secondary portion 35 of the shoulder longitudinal sipe 32. In this embodiment, the shoulder lateral sipes 33 are composed of an inner portion 33A formed in the shoulder land portion 5 and an outer portion 33B formed in the buttress region B. The tire axial length L6 of the inner portion 33A is formed to be smaller than the tire axial length L7 of the outer portion 33B. The length L6 of the inner portion 33A is preferably 15% or more of the length L7 of the outer portion 33B, more preferably 20% or more, and more preferably 35% or less, and even more preferably 30% or less.

Figure 9 is a plan view of the middle land portion 6 in Figure 4. As shown in Figure 9, the middle land portion 6 is provided with a middle lug groove 40, a first middle sipe 41 that crosses the middle land portion 6, and a second middle sipe 42 that has one end terminating within the middle land portion 6. In this embodiment, the first middle sipe 41 and the second middle sipe 42 are provided one each between the middle lug grooves 40, 40 adjacent to each other in the tire circumferential direction.

In this embodiment, the middle lug groove 40 extends from the shoulder circumferential groove 3 toward the axially inner side of the tire and terminates within the middle land portion 6. The middle lug groove 40 extends, for example, parallel to the tire axial direction. In this embodiment, the middle lug groove 40 terminates axially outward of the axial middle 6c of the middle land portion 6. Such a middle lug groove 40 suppresses excessive reduction in the rigidity of the middle land portion 6. The axial length L9 of the middle lug groove 40 is preferably 20% or more of the axial width Wm of the middle land portion 6, more preferably 25% or more, more preferably 40% or less, and more preferably 35% or less. In this specification, the term "parallel to the tire axial direction" includes not only an angle of 0 degrees with respect to the tire axial direction, but also an angle of 20 degrees or less.

The groove width W6 of the middle lug groove 40 becomes smaller continuously toward the outside in the tire axial direction. Such a middle lug groove 40 can smoothly drain water in the groove to the shoulder circumferential groove 3. The maximum value of the groove width W6 of the middle lug groove 40 is preferably 5% or more of the width Wm of the middle land portion 6, more preferably 10% or more, and more preferably 25% or less, and more preferably 20% or less.

The first middle sipe 41 includes, for example, an axial portion 41A extending parallel to the tire axial direction, and an inclined portion 41B inclined more toward the tire axial direction than the axial portion 41A. The axial portion 41A extends from the shoulder circumferential groove 3 toward the inside in the tire axial direction. In this embodiment, the axial portion 41A extends linearly. The axial portion 41A extends from the shoulder circumferential groove 3 toward the inside in the tire axial direction beyond the middle 6c of the middle land portion 6. The inclined portion 41B is connected to the axial portion 41A and is disposed closer to the tire equator C than the axial portion 41A. The inclined portion 41B is connected to, for example, the middle circumferential groove 4. In this embodiment, the inclined portion 41B includes an arc-shaped portion 41d connected to the axial portion 41A. The arc-shaped portion 41d is formed to be convex on either side of the tire circumferential direction (the lower side in the middle land portion 6 in FIG. 9). Such an arc-shaped portion 41d prevents excessive reduction in the rigidity of the middle land portion 6.

In this embodiment, the second middle sipes 42 extend from the shoulder circumferential grooves 3 toward the inside in the tire axial direction and terminate within the middle land portion 6. The second middle sipes 42 extend, for example, parallel to the tire axial direction. In this embodiment, the second middle sipes 42 terminate closer to the tire equator C than the middle 6c of the middle land portion 6.

Although a tire according to one embodiment of the present disclosure has been described in detail above, the present disclosure is not limited to the specific embodiment described above and can be modified and implemented in various ways.

Prototype tires were made with the basic pattern shown in Figure 4. Each prototype tire was then tested for wet performance, steering stability, and resistance to uneven wear. The common specifications and test methods for each prototype tire are as follows:

<Wet performance, steering stability and uneven wear resistance>
Each sample tire was mounted on the following test vehicle. A test driver ran the test vehicle on a test course with a wet asphalt road surface and a dry asphalt road surface, and evaluated the wet performance and steering stability based on the stability and operability of each vehicle by sensory evaluation. After running on a dry asphalt road surface, the test driver observed the occurrence of uneven wear in the tread portion and evaluated the uneven wear resistance by sensory evaluation. The results are shown in a score based on Example 1 being 100. The higher the value, the better the performance.
Tire size: 205/65R16
Rim: 16 x 6.5J
Internal pressure (kPa): 390 (front wheel) / 420 (rear wheel)
Vehicle: Commercial vehicle with 2000cc displacement The test results are shown in Table 1.
The "number of shoulder horizontal sipes" in Table 1 is the number of shoulder horizontal sipes connected to one shoulder longitudinal sipe.

The test results confirmed that the tires of the embodiment example had reduced deterioration in steering stability and uneven wear resistance. In addition, the tires of the embodiment example had excellent wet performance.

[Additional Notes]
The present disclosure includes the following aspects.

[Disclosure 1]
A tire having a tread portion,
The tread portion includes a shoulder land portion divided by a shoulder circumferential groove and a tread end,
The shoulder land portion is divided into a plurality of shoulder block elements by a plurality of shoulder lateral grooves,
each of the shoulder circumferential grooves includes a first portion extending from a tread edge toward an axially inner side of the tire, a second portion on the shoulder circumferential groove side inclined with respect to the first portion, and a communicating portion connecting the first portion and the second portion, so that each of the shoulder block elements includes a convex corner portion that is convex toward an outer side of the block at the communicating portion,
the block side wall of the convex corner portion includes a first side wall extending along the first portion, a second side wall extending along the second portion, and a triangular third side wall spanning the first side wall, the second side wall, and the block tread surface,
The third side wall terminates radially outward of a groove bottom of the shoulder lateral groove.
tire.
[Disclosure 2]
The third side wall includes a tread side edge that is a boundary with the block tread, a first edge that is a boundary with the first side wall, and a second edge that is a boundary with the second side wall,
The tire of Disclosure 1, wherein the tread side edge is longer than the first edge and the second edge.
[Disclosure 3]
The tire according to Disclosure 2, wherein a connection portion between the first edge and the second edge is located in a range of 30% to 50% of a maximum groove depth of the shoulder lateral groove.
[Disclosure 4]
The tire according to Disclosure 3, wherein the length of the tread side edge is greater than the shortest length between the connection portion and the tread side edge in a plan view of the tread.
[Disclosure 5]
The tire of disclosure 4, wherein the shortest length is between 3 and 7 mm.
[Disclosure 6]
The tire according to any one of disclosures 1 to 5, wherein the second portion extends from the shoulder circumferential groove.
[Disclosure 7]
The tire according to any one of disclosures 1 to 6, wherein the communication portion is disposed axially outward of an axial middle portion of the shoulder land portion.
[Disclosure 8]
The tire according to any one of claims 1 to 7, wherein a groove width of the first portion is larger than a groove width of the second portion.
[Disclosure 9]
The tire according to any one of claims 1 to 8, wherein the angle of the first portion with respect to the tire axial direction is 20 degrees or less.
[Disclosure 10]
The tire according to any one of disclosures 1 to 9, wherein an angle between the shoulder circumferential groove and the second portion is 30 to 50 degrees.
[Disclosure 11]
The tire according to any one of claims 1 to 10, wherein the third sidewall is connected to a tread edge.
[Disclosure 12]
The tire according to any one of disclosures 1 to 11, wherein the first portion extends axially outwardly of a tread edge.

Reference Signs List 1 Tire 5 Shoulder land portion 5a Shoulder block element 7 Shoulder lateral groove 7s Groove bottom 8 Block side wall 9 Block tread surface 11 First portion 12 Second portion 13 Connecting portion 15 Convex corner portion 17 First side wall 18 Second side wall 19 Third side wall

Claims (12)

A tire having a tread portion,
The tread portion includes a shoulder land portion divided by a shoulder circumferential groove and a tread end,
The shoulder land portion is divided into a plurality of shoulder block elements by a plurality of shoulder lateral grooves,
each of the shoulder circumferential grooves includes a first portion extending from a tread edge toward an axially inner side of the tire, a second portion on the shoulder circumferential groove side inclined with respect to the first portion, and a communicating portion connecting the first portion and the second portion, so that each of the shoulder block elements includes a convex corner portion that is convex toward an outer side of the block at the communicating portion,
the block side wall of the convex corner portion includes a first side wall extending along the first portion, a second side wall extending along the second portion, and a triangular third side wall spanning the first side wall, the second side wall, and the block tread surface,
The third side wall terminates radially outward of a groove bottom of the shoulder lateral groove.
tire. The third side wall includes a tread side edge that is a boundary with the block tread, a first edge that is a boundary with the first side wall, and a second edge that is a boundary with the second side wall,
The tire of claim 1 , wherein the tread edge is longer than the first edge and the second edge. The tire according to claim 2, wherein the connection between the first edge and the second edge is located in a range of 30% to 50% of the maximum groove depth of the shoulder lateral groove. The tire according to claim 3, wherein the length of the tread side edge is greater than the shortest length between the connection portion and the tread side edge in a plan view of the tread. The tire according to claim 4, wherein the shortest length is 3 to 7 mm. The tire according to any one of claims 1 to 5, wherein the second portion extends from the shoulder circumferential groove. The tire according to any one of claims 1 to 6, wherein the communication portion is disposed axially outward of the axial center of the shoulder land portion. The tire according to any one of claims 1 to 7, wherein the groove width of the first portion is greater than the groove width of the second portion. The tire according to any one of claims 1 to 8, wherein the angle of the first portion with respect to the tire axial direction is 20 degrees or less. The tire according to any one of claims 1 to 9, wherein the angle between the shoulder circumferential groove and the second portion is 30 to 50 degrees. The tire according to any one of claims 1 to 10, wherein the third sidewall is connected to the tread edge. The tire according to any one of claims 1 to 11, wherein the first portion extends axially outward from the tread edge.

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