tire

Abstract

To provide a tire that can improve snow performance while ensuring durability. [Solution] The tread portion 2 is provided with a plurality of circumferential main grooves 30, a plurality of lug grooves 40, and a plurality of land portions 20. The shoulder land portion 25, which is the outermost of the land portions 20 in the tire width direction, has a tread side wall 26, which is the end face of the tread portion 2 in the tire width direction, and has a recess 71 that extends inward in the tire radial direction along the tread side wall 26 from the tread contact surface 3 and recesses inward in the tire width direction, and a convex portion 75 that extends inward in the tire radial direction along the tread side wall 26 from the tread contact surface 3 and convex outward in the tire width direction, and has adjacent uneven portions 70 in the tire circumferential direction, the depth of the recess 71 from the tread side wall 26 gradually changing in the tire circumferential direction, and the uneven portions 70 have a continuous wall surface 78 where the wall surface 72 of the recess 71 and the wall surface 76 of the convex portion 75 are continuous.

Description

Technical Field

[0001] The present invention relates to a tire.

Background Art

[0002] In the case of a studless tire mainly used as a winter tire, snow performance, which is the running performance on a snow-covered road surface, is required. Generally, in a studless tire, transverse grooves are provided on the ground contact surface of the tread portion to enhance snow performance, and when running on a snow-covered road surface, snow columns are formed by the transverse grooves and the snow columns are sheared to generate traction and braking force. Further, when running on a snow-covered road surface, a part of the tread portion of the tire may sink into the snow. When a part of the tread portion sinks into the snow, not only the ground contact surface of the tread portion but also the side surface of the shoulder portion come into contact with the snow on the road surface. Therefore, among conventional winter tires, there are some that also use the side surface of the shoulder portion to improve snow performance.

[0003] For example, in the pneumatic tire described in Patent Document 1, a plurality of convex portions protruding outward in the tire axial direction are arranged on the buttress surface, and at least one of the plurality of convex portions extends inward in the tire radial direction from the ground contact surface and curves toward the leading side in the rotational direction, thereby enhancing snow performance. Further, in the pneumatic tire described in Patent Document 2, the shoulder block has a square shoulder portion having an unchamfered corner portion and a round shoulder portion whose shape is substantially an arc-shaped curved surface when viewed in a cross section along the tire rotation axis, and on the shoulder sidewall, there are a plurality of auxiliary land portions that are continuous on the inner side in the tire diameter direction of the square shoulder portion and the round shoulder portion and form a stepped shape when viewed in a cross section along the tire rotation axis, whereby the cornering performance, traction performance, and braking performance on snow can be improved.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

[0005] Here, the protrusions provided on the buttress surface or shoulder sidewall to improve snow performance can enhance snow performance by creating resistance against the snow on the road surface when a vehicle is driving on a snowy road. Therefore, snow performance tends to improve as the height of the protrusions increases. On the other hand, when the height of the protrusions is increased, stress concentration is more likely to occur near the protrusions, which can lead to breakage of the protrusions or uneven wear due to stress concentration, potentially reducing durability. For this reason, improving snow performance without reducing durability has been extremely difficult.

[0006] The present invention has been made in view of the above, and aims to provide a tire that can improve snow performance while ensuring durability. [Means for solving the problem]

[0007] To solve the above-mentioned problems and achieve the objective, the tire according to the present invention comprises a tread portion having a plurality of circumferential main grooves extending in the tire circumferential direction, a plurality of lug grooves extending in the tire width direction, and a plurality of land portions partitioned by the circumferential main grooves and the lug grooves, wherein the shoulder land portion, which is the outermost land portion in the tire width direction among the plurality of land portions, has adjacent uneven portions in the tire circumferential direction on the tread side wall, which is the end face of the tread portion in the tire width direction and is partitioned on both sides in the tire circumferential direction by the lug grooves, and a recess extending inward in the tire radial direction along the tread side wall from the tread contact surface and a convex portion extending inward in the tire radial direction along the tread side wall from the tread contact surface and a convex portion that protrudes outward in the tire width direction, wherein the recess is formed with a gradually changing depth from the tread side wall in the tire circumferential direction, and the uneven portion has a continuous wall surface where the wall surface of the recess and the wall surface of the convex portion are continuous.

[0008] Furthermore, the above-mentioned tire is equipped with a display unit that specifies the direction of tire rotation, and it is preferable that the recessed portion of the uneven portion is located on the side that makes contact with the convex portion in the direction of tire rotation.

[0009] Furthermore, in the above-described tire, a plurality of sipes extending in the tire width direction are arranged in the tire circumferential direction on the tread contact surface of the shoulder land portion, and it is preferable that the position in the tire circumferential direction of the deepest part of the recess from the tread side wall of the uneven portion is located between the sipe that is located furthest back in the tire rotation direction and the sipe adjacent to that sipe in the tire circumferential direction.

[0010] Furthermore, in the above-described tire, the shoulder portion has a plurality of sipes extending in the tire width direction arranged in the tire circumferential direction on the tread contact surface, and the uneven portion has two of the uneven portions arranged in the tire circumferential direction on one of the tread sidewalls, and of the two uneven portions, the uneven portion located on the leading side in the tire rotation direction preferably has the deepest part of the recess from the tread sidewall located between the sipe located on the leading side in the tire rotation direction and the sipe adjacent to that sipe in the tire circumferential direction.

[0011] Furthermore, in the above-mentioned tire, it is preferable that the length La of the uneven portion in the tire circumferential direction is 25% or more of the length Lb of the tread side wall on which the uneven portion is arranged in the tire circumferential direction.

[0012] Furthermore, in the above-mentioned tire, it is preferable that the relationship between the depth Da of the recess at the deepest part from the tread sidewall and the groove depth Db of the lug groove that demarcates the shoulder land portion is within the range of 0.35 ≤ Da / Db ≤ 0.55.

[0013] Furthermore, in the above-mentioned tire, it is preferable that the relationship between the length L3 of the uneven portion in the sidewall direction, which is perpendicular to the circumferential direction of the tire and along the tread sidewall where the uneven portion is arranged, and the length L4 of the tread sidewall in the sidewall direction, is within the range of 0.5 ≤ L3 / L4 ≤ 0.9.

[0014] Furthermore, in the above-mentioned tire, it is preferable that the relationship between the height L5 of the protrusion from the tread sidewall and the depth Da of the recess at the deepest part of the recess from the tread sidewall is within the range of 0.5 ≤ L5 / Da ≤ 0.8.

[0015] Furthermore, in the above-mentioned tire, it is preferable that the inclination angle α of the continuous wall surface with respect to the tread side wall of the uneven portion is within the range of 45° ≤ α ≤ 90°.

[0016] Also, in the above tire, for the shoulder land portion where the concavo-convex portions are arranged, the relationship between the width L1 of the shoulder land portion in the tire width direction and the length L2 of the tread sidewall in the tire circumferential direction satisfies L2 / L1 < 1.2, and it is preferable that one of the concavo-convex portions is arranged on one of the tread sidewalls.

[0017] Also, in the above tire, for the shoulder land portion where the concavo-convex portions are arranged, the relationship between the width L1 of the shoulder land portion in the tire width direction and the length L2 of the tread sidewall in the tire circumferential direction satisfies L2 / L1 ≥ 1.2, and it is preferable that two of the concavo-convex portions are arranged side by side in the tire circumferential direction on one of the tread sidewalls.

Advantages of the Invention

[0018] The tire according to the present invention has an effect that it can improve the performance on snow while ensuring durability.

Brief Description of the Drawings

[0019] [Figure 1] FIG. 1 is a tire meridian cross-sectional view showing a main part of a pneumatic tire according to an embodiment. [Figure 2] FIG. 2 is a view taken along the arrow A-A in FIG. 1. ​​​​​​​​​​​​​​​​FIG. 8 is an explanatory view showing a modified example of a pneumatic tire according to an embodiment, in which two concavo-convex portions are arranged on one tread sidewall of the shoulder land portion. [Figure 9A] FIG. 9A is a chart showing the results of a performance evaluation test of a pneumatic tire. [Figure 9B] FIG. 9B is a chart showing the results of a performance evaluation test of a pneumatic tire.

Mode for Carrying Out the Invention

[0020] Hereinafter, embodiments of the tire according to the present invention will be described in detail based on the drawings. Note that the present invention is not limited by this embodiment. In addition, the components in the following embodiments include those that can be replaced by those skilled in the art and can be easily conceived, or those that are substantially the same.

[0021] [Embodiment] In the following description, as an example of the tire according to the present invention, a pneumatic tire 1 will be used for explanation. The pneumatic tire 1, which is an example of a tire, can be filled with air, an inert gas such as nitrogen, and other gases.

[0022] Furthermore, in the following explanation, the tire radial direction refers to the direction perpendicular to the tire rotation axis (not shown), which is the rotation axis of the pneumatic tire 1. The inner side of the tire radial direction refers to the side toward the tire rotation axis in the tire radial direction, and the outer side of the tire radial direction refers to the side away from the tire rotation axis in the tire radial direction. The tire circumferential direction refers to the direction around the tire rotation axis as the central axis. The tire width direction refers to the direction parallel to the tire rotation axis. The inner side of the tire width direction refers to the side toward the tire equatorial plane (tire equator line) CL in the tire width direction, and the outer side of the tire width direction refers to the side away from the tire equatorial plane CL in the tire width direction. The tire equatorial plane CL is a plane perpendicular to the tire rotation axis and passing through the center of the tire width of the pneumatic tire 1. The position of the tire equatorial plane CL in the tire width direction coincides with the center line in the tire width direction, which is the center position of the pneumatic tire 1 in the tire width direction. The tire width is the distance in the tire width direction between the outermost parts in that direction, that is, the distance between the parts furthest from the tire equatorial plane CL in that direction. The tire equatorial line is a line on the tire equatorial plane CL that runs along the circumferential direction of the pneumatic tire 1. In the following explanation, the tire meridional section refers to the cross-section obtained when the tire is cut by a plane containing the tire's axis of rotation.

[0023] Figure 1 is a meridional cross-sectional view of a pneumatic tire 1 according to an embodiment, showing the main parts of the tire. The pneumatic tire 1 according to this embodiment has a designated mounting direction relative to the vehicle, that is, the direction when mounted on the vehicle. That is, in the pneumatic tire 1 shown in this embodiment, the side facing inward towards the vehicle when mounted on the vehicle is designated as the inner side in the vehicle mounting direction, and the side facing outward towards the vehicle when mounted on the vehicle is designated as the outer side in the vehicle mounting direction. Note that the designation of the inner and outer sides in the vehicle mounting direction is not limited to when mounted on a vehicle. For example, when assembled on a rim, the orientation of the rim relative to the inside and outside of the vehicle is determined in the tire width direction, so when assembled on a rim, the pneumatic tire 1 has designated orientations relative to the inner and outer sides in the vehicle mounting direction in the tire width direction. The pneumatic tire 1 also has a mounting direction indicator (not shown) that indicates the mounting direction relative to the vehicle. The mounting direction indicator is composed of, for example, marks or indentations on the sidewall portion 8 of the tire. For example, ECER30 (Regulation 30 of the Economic Commission of Europe) mandates that a mounting direction indicator be provided on the sidewall portion 8, which faces outward in the direction of vehicle mounting when the product is mounted on a vehicle.

[0024] Furthermore, the pneumatic tire 1 according to this embodiment is a pneumatic tire 1 in which the direction of rotation is specified when mounted on a vehicle. For this reason, the pneumatic tire 1 according to this embodiment has a rotation direction indicator (not shown) that specifies the direction of tire rotation. The rotation direction indicator is composed of, for example, marks or indentations on the sidewall. Also, the pneumatic tire 1 according to this embodiment is a pneumatic tire 1 mainly used for passenger cars.

[0025] In this embodiment, the pneumatic tire 1 has a tread portion 2 disposed at the outermost part in the radial direction of the tire when viewed in the meridional cross-section of the tire, and the tread portion 2 has a tread rubber 4 made of a rubber composition. Furthermore, the surface of the tread portion 2, that is, the part that comes into contact with the road surface when the vehicle (not shown) equipped with the pneumatic tire 1 is running, is formed as a tread contact surface 3, and the tread contact surface 3 constitutes a part of the contour of the pneumatic tire 1.

[0026] Shoulder portions 5 are located at both outer ends of the tread portion 2 in the tire width direction, and sidewall portions 8 are arranged on the inner side of the shoulder portions 5 in the tire diameter direction. In other words, the sidewall portions 8 are located on both sides of the tread portion 2 in the tire width direction. To put it another way, the sidewall portions 8 are located at two locations on both sides of the pneumatic tire 1 in the tire width direction, forming the outermost exposed portion of the pneumatic tire 1 in the tire width direction.

[0027] A bead portion 10 is located on the radially inner side of each sidewall portion 8 located on both sides in the tire width direction. Similar to the sidewall portions 8, the bead portions 10 are arranged in two places on both sides of the tire equatorial plane CL; that is, a pair of bead portions 10 are arranged on both sides in the tire width direction of the tire equatorial plane CL. A bead core 11 is provided in each bead portion 10, and a bead filler 12 is provided on the radially outer side of the bead core 11. The bead core 11 is an annular member formed by bundling bead wires, which are steel wires, into a ring shape, and the bead filler 12 is a rubber member positioned radially outer of the bead core 11.

[0028] Furthermore, a belt layer 14 is arranged in the tread portion 2. The belt layer 14 is composed of a multilayer structure in which multiple belts 141 and 142 and a belt cover 143 are laminated, and in this embodiment, two layers of belts 141 and 142 are laminated. The belts 141 and 142 that make up the belt layer 14 are made by covering multiple belt cords made of steel or organic fiber materials such as polyester, rayon, or nylon with coated rubber and rolling them, and the belt angle, which is defined as the inclination angle of the belt cords with respect to the circumferential direction of the tire, is within a predetermined range (for example, 20° or more and 55° or less). Also, the belt angles of the two layers of belts 141 and 142 are different from each other. For this reason, the belt layer 14 is composed of a so-called cross-ply structure in which the two layers of belts 141 and 142 are laminated with the inclination directions of the belt cords intersecting each other. In other words, the two layers of belts 141 and 142 are arranged as so-called cross belts, with the belt cords of each belt 141 and 142 crossing each other.

[0029] Furthermore, the belt cover 143 is constructed by covering multiple belt cover cords made of steel or organic fiber materials such as polyester, rayon, or nylon with coated rubber and rolling them, and the belt angle, defined as the inclination angle of the belt cover cords with respect to the tire circumferential direction, is within a predetermined range (for example, 0° or more and 10° or less). Also, the belt cover 143 is a strip material made by covering one or more belt cover cords with coated rubber, and this strip material is constructed by winding it spirally around the tire rotation axis from the outside of the two layers of belts 141 and 142 in the tire radial direction.

[0030] A carcass layer 13 containing the cords of radial ply is continuously provided on the inner side of the belt layer 14 in the tire radial direction and on the tire equatorial plane CL side of the sidewall portion 8. Therefore, the pneumatic tire 1 according to this embodiment is configured as a so-called radial tire. The carcass layer 13 has a single-layer structure consisting of one carcass ply or a multi-layer structure consisting of multiple carcass ply stacked together, and is toroidally stretched between a pair of bead portions 10 arranged on both sides in the tire width direction to form the tire's skeleton.

[0031] More specifically, the carcass layer 13 is positioned from one of a pair of bead portions 10 located on both sides in the tire width direction to the other bead portion 10, and is wrapped around the bead core 11 in the tire width direction outward along the bead core 11 so as to enclose the bead core 11 and the bead filler 12. The bead filler 12 is a rubber material that is placed in the space formed on the radially outward side of the bead core 11 when the carcass layer 13 is folded back at the bead portion 10 in this way. The belt layer 14 is positioned on the radially outward side of the portion of the carcass layer 13 located in the tread portion 2 that spans between the pair of bead portions 10 in this way. The carcass ply of the carcass layer 13 is constructed by covering multiple carcass cords made of steel or organic fiber materials such as aramid, nylon, polyester, or rayon with a coating rubber and then rolling them. The carcass cords that make up the carcass ply are arranged in parallel, with an angle in the tire's circumferential direction that aligns with the tire's meridian, while also maintaining an angle in the circumferential direction of the tire.

[0032] In the bead portion 10, rim cushion rubber 17 is provided on the inner side in the tire radial direction and the outer side in the tire width direction of the bead core 11 and the reversal portion of the carcass layer 13, forming the contact surface of the bead portion 10 with the rim flange. In addition, an inner liner 16 is formed along the carcass layer 13 on the inside of the carcass layer 13, or on the inner side of the carcass layer 13 in the pneumatic tire 1. The inner liner 16 forms the inner surface 18 of the tire, which is the inner surface of the pneumatic tire 1.

[0033] Figure 2 is a view taken along arrow AA in Figure 1. The tread portion 2 has multiple circumferential main grooves 30 extending in the tire circumferential direction and multiple lug grooves 40 extending in the tire width direction formed on the tread contact surface 3. These circumferential main grooves 30 and lug grooves 40 divide the surface of the tread portion 2 into multiple land areas 20. In this embodiment, five circumferential main grooves 30 are formed in a line in the tire width direction.

[0034] More specifically, the circumferential main groove 30 has five grooves: a center circumferential main groove 31 located near the tire equatorial plane CL, two inner circumferential main grooves 32 located on both sides of the tire equatorial plane CL in the tire width direction, and two outer circumferential main grooves 35, one on each side of the two inner circumferential main grooves 32 in the tire width direction. In this embodiment, the center circumferential main groove 31 is located near the tire equatorial plane CL and is positioned outward relative to the tire equatorial plane CL in the vehicle mounting direction.

[0035] The circumferential main groove 30 referred to here is a groove that is required to display a wear indicator (slip sign) as stipulated by JATMA, and generally has a groove width of 5.0 mm or more and a groove depth of 6.5 mm or more.

[0036] The land area 20, demarcated by the circumferential main groove 30, has a center land area 21, a second land area 22, and a shoulder land area 25. Of these, the center land area 21 is located between the adjacent center circumferential main groove 31 and the inner circumferential main groove 32 in the tire width direction. The second land area 22 is located between the adjacent inner circumferential main groove 32 and the outer circumferential main groove 35 in the tire width direction, with the inner portion in the tire width direction demarcated by the inner circumferential main groove 32 and the outer portion in the tire width direction demarcated by the outer circumferential main groove 35.

[0037] Furthermore, the shoulder land portion 25 is a land portion 20 located on the outer side in the tire width direction of the outer circumferential main groove 35, and the inner side in the tire width direction is demarcated by the outer circumferential main groove 35. For this reason, the shoulder land portion 25 is the land portion 20 that is located furthest out of the multiple land portions 20 in the tire width direction. These center land portion 21, second land portion 22, and shoulder land portion 25 are respectively located on both sides of the center circumferential main groove 31 in the tire width direction.

[0038] Of the five circumferential main grooves 30, the center circumferential main groove 31 and the two outer circumferential main grooves 35 are formed to extend linearly along the tire's circumferential direction. On the other hand, of the five circumferential main grooves 30, the two inner circumferential main grooves 32 are each formed in a zigzag shape by having at least one of the groove walls on both sides in the groove width direction extend in the tire's circumferential direction while oscillating in the tire width direction.

[0039] More specifically, when the two inner circumferential main grooves 32 are designated as the first inner circumferential main groove 32a and the second inner circumferential main groove 32b, in the first inner circumferential main groove 32a, the groove wall on the outer side in the tire width direction is formed in a zigzag shape, while the groove wall on the inner side in the tire width direction extends linearly along the tire circumferential direction. In the second inner circumferential main groove 32b, the entire second inner circumferential main groove 32b extends in the tire circumferential direction while oscillating in the tire width direction, thus forming a zigzag shape. Therefore, in the second inner circumferential main groove 32b, the groove width is kept constant, while both groove walls on both sides in the groove width direction are formed in a zigzag shape.

[0040] In this embodiment, the first inner circumferential main groove 32a is one of two inner circumferential main grooves 32 arranged on both sides of the tire equatorial plane CL, and is positioned on the inner side in the vehicle mounting direction relative to the tire equatorial plane CL. The second inner circumferential main groove 32b is one of two inner circumferential main grooves 32 arranged on both sides of the tire equatorial plane CL, and is positioned on the outer side in the vehicle mounting direction relative to the tire equatorial plane CL.

[0041] Furthermore, the lug groove 40 has a center lug groove 41, an inner lug groove 42, an outer lug groove 44, and a shoulder lug groove 45. Of these, the center lug groove 41 is located between the center circumferential main groove 31 and the inner circumferential main groove 32, which are adjacent in the tire width direction. The center lug groove 41 extends in the tire width direction and is inclined in the tire circumferential direction with respect to the tire width direction, with one end opening into the center circumferential main groove 31 and the other end opening into the inner circumferential main groove 32. As a result, the center land area 21, which is partitioned by the center circumferential main groove 31, the inner circumferential main groove 32, and the center lug groove 41, is a block-shaped land area 20, with both sides in the tire width direction partitioned by the center circumferential main groove 31 and the inner circumferential main groove 32, and both sides in the tire circumferential direction partitioned by the center lug groove 41.

[0042] Furthermore, the inner lug groove 42 is a lug groove 40 positioned inward in the vehicle mounting direction relative to the tire equatorial plane CL, and is located between the first inner circumferential main groove 32a and the outer circumferential main groove 35 adjacent to the first inner circumferential main groove 32a. In other words, the inner lug groove 42 is located in the inner second land portion 22a, which is one of the second land portions 22 positioned on both sides of the tire width direction of the tire equatorial plane CL, and is located inward in the vehicle mounting direction relative to the tire equatorial plane CL, between the first inner circumferential main groove 32a and the outer circumferential main groove 35.

[0043] Thus, the inner lug groove 42, which is a lug groove 40 located in the land area 20 that is partitioned on both sides in the tire width direction by the circumferential main groove 30, has a first inner lug groove 42a and a second inner lug groove 42b. The first inner lug groove 42a has one end that opens into the outer circumferential main groove 35 and the other end that terminates within the inner second land area 22a. The second inner lug groove 42b has one end that opens into the first inner circumferential main groove 32a and the other end that terminates within the inner second land area 22a.

[0044] These first inner lug grooves 42a and second inner lug grooves 42b are arranged alternately in the circumferential direction of the tire. Furthermore, both the first inner lug grooves 42a and the second inner lug grooves 42b extend in the tire width direction and are inclined in the circumferential direction with respect to the tire width direction. In the inner second land portion 22a, one end of both the first inner lug grooves 42a and the second inner lug grooves 42b terminates within the inner second land portion 22a and is not divided in the circumferential direction of the tire by the inner lug grooves 42. Therefore, the inner second land portion 22a is a rib-shaped land portion 20 that is formed continuously in the circumferential direction of the tire.

[0045] Furthermore, the outer lug groove 44 is a lug groove 40 positioned on the inner and outer sides in the vehicle mounting direction relative to the tire equatorial plane CL, and is located between the second inner circumferential main groove 32b and the outer circumferential main groove 35 adjacent to the second inner circumferential main groove 32b. The outer lug groove 44 extends in the tire width direction and is inclined in the tire circumferential direction with respect to the tire width direction, with one end opening into the second inner circumferential main groove 32b and the other end opening into the outer circumferential main groove 35. In this way, the outer lug groove 44 positioned between the second inner circumferential main groove 32b and the outer circumferential main groove 35 is located on the outer side in the vehicle mounting direction relative to the tire equatorial plane CL, and is a lug groove 40 that demarcates the outer second land portion 22b, which is the second land portion 22 located between the second inner circumferential main groove 32b and the outer circumferential main groove 35. Therefore, the outer second land portion 22b is a block-shaped land portion 20, with both sides in the tire width direction demarcated by the second inner circumferential main groove 32b and the outer circumferential main groove 35, and both sides in the tire circumferential direction demarcated by the outer lug groove 44.

[0046] Furthermore, the shoulder lug grooves 45 are positioned on the outer side in the tire width direction of the outer circumferential main grooves 35 located on both sides in the tire width direction of the tire equatorial plane CL. Each shoulder lug groove 45 is formed extending in the tire width direction, with its inner end in the tire width direction opening into the outer circumferential main groove 35, and its outer end in the tire width direction opening toward the outer side in the tire width direction of the tread portion 2. In this way, the shoulder lug grooves 45, positioned on the outer side in the tire width direction of the outer circumferential main groove 35 and extending in the tire width direction, form a lug groove 40 that, together with the outer circumferential main groove 35, defines the shoulder land portion 25. Therefore, the shoulder land portion 25 is a block-shaped land portion 20, with both sides in the tire circumferential direction defined by the shoulder lug grooves 45.

[0047] Furthermore, the contact edge T is located on the outer portion in the tire width direction of the tread contact surface 3 of the shoulder land portion 25. The contact edge T is defined as the position of the maximum width in the tire width direction at the contact surface between the pneumatic tire 1 and the flat plate when the pneumatic tire 1 is mounted on a specified rim, a specified internal pressure is applied, and the tire is placed perpendicular to the flat plate and a load corresponding to a specified load is applied.

[0048] The term "specified rim" here refers to the "standard rim" specified by JATMA, the "Design Rim" specified by TRA, or the "Measuring Rim" specified by ETRTO. The specified internal pressure refers to the "maximum air pressure" specified by JATMA, the maximum value listed in "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" specified by TRA, or the "INFLATION PRESSURES" specified by ETRTO. The specified load refers to the "maximum load capacity" specified by JATMA, the maximum value in "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" specified by TRA, or the "LOAD CAPACITY" specified by ETRTO. However, in JATMA, for passenger car tires, the specified internal pressure is 180 kPa and the specified load is 88% of the maximum load capacity.

[0049] The lug grooves 40 formed in the tread portion 2 in this manner generally have a groove width of 1.0 mm or more and a groove depth of 3.0 mm or more.

[0050] Furthermore, a circumferential narrow groove 50 is arranged in the outer second land portion 22b, which is located between the second inner circumferential main groove 32b and the outer circumferential main groove 35, and extends in the circumferential direction of the tire. The circumferential narrow groove 50 is a groove that extends in the circumferential direction of the tire with a groove width narrower than the groove width of the circumferential main groove 30, and the groove width of the circumferential narrow groove 50 is between 1.0 mm and 8.0 mm.

[0051] The circumferential groove 50 is positioned on the outer second land portion 22b, which is located on the outer side in the vehicle mounting direction relative to the tire equatorial plane CL, and extends in the circumferential direction of the tire. Both ends in the circumferential direction of the tire open into the outer lug grooves 44 that define the outer second land portion 22b. The circumferential groove 50 is formed to extend in the circumferential direction of the tire while having a portion that bends in the tire width direction. In this embodiment, the circumferential groove 50 is bent at two locations, so that it is positioned on the outer second land portion 22b in a crank shape.

[0052] Furthermore, on the shoulder land area 25 located on the outer side in the tire width direction of the outer circumferential main groove 35, there is a shoulder narrow groove 55 that extends in the tire circumferential direction and has a groove width narrower than the circumferential narrow groove 50. One end of the shoulder narrow groove 55 that extends in the tire circumferential direction opens into the shoulder lug groove 45, and the other end terminates within the shoulder land area 25. For the shoulder narrow grooves 55 located on the shoulder land area 25 that are on the same side in the tire width direction with respect to the tire equatorial plane CL, the end that opens into the shoulder lug groove 45 is always on the same side in the tire circumferential direction. In other words, the shoulder narrow grooves 55 located on the shoulder land area 25 that are partitioned by the same outer circumferential main groove 35 are all oriented in the tire circumferential direction.

[0053] Furthermore, the shoulder grooves 55 positioned on the inside in the vehicle mounting direction relative to the tire equatorial plane CL and the shoulder grooves 55 positioned on the outside in the vehicle mounting direction have ends on opposite sides: one end opening into the shoulder lug groove 45 and the other ending terminating within the shoulder land portion 25. In other words, the shoulder grooves 55 positioned on the inside in the vehicle mounting direction relative to the tire equatorial plane CL and the shoulder grooves 55 positioned on the outside in the vehicle mounting direction have opposite orientations in the circumferential direction of the tire.

[0054] Furthermore, each land portion 20 has a plurality of sipes 60 extending in the tire width direction, arranged in the tire circumferential direction on the tread contact surface 3. The sipes 60 arranged on the land portion 20 are formed and arranged in a zigzag pattern, for example, by extending in the tire width direction and repeatedly bending and oscillating in the tire circumferential direction. The ends of each sipe 60 may terminate within the land portion 20 or open into other grooves. The pneumatic tire 1 according to this embodiment is applied to a studless tire that ensures driving performance on icy and snowy road surfaces by arranging the sipes 60 on each land portion 20 in this way.

[0055] The sipes 60 referred to here are formed in the shape of narrow grooves on the tread contact surface 3. When a pneumatic tire 1 is mounted on a specified rim and under specified internal pressure conditions, the walls constituting the narrow grooves do not come into contact with each other when unloaded. However, when a vertical load is applied to a flat plate, and the narrow grooves are located on the contact surface formed on the flat plate, or when the land portion 20 on which the narrow grooves are formed collapses, the walls constituting the narrow grooves, or at least a portion of the parts provided on the walls, come into contact with each other due to the deformation of the land portion 20. Generally, the sipes 60 have a sipe width of less than 1.0 mm and a sipe depth of 2.0 mm or more, so that they close when the tire makes contact with the ground.

[0056] Furthermore, the sipe 60 may be a so-called three-dimensional sipe or a two-dimensional sipe. A three-dimensional sipe, as used here, is a sipe 60 that has a curved wall surface with amplitude in the width direction of the sipe 60 in both a cross-sectional view with the length direction of the sipe 60 as the normal direction (a cross-sectional view including the width direction and depth direction of the sipe 60) and a cross-sectional view with the depth direction of the sipe 60 as the normal direction (a cross-sectional view including the width direction and depth direction of the sipe 60). A two-dimensional sipe, on the other hand, is a sipe 60 that has a straight wall surface in any cross-sectional view with the length direction of the sipe 60 as the normal direction (a cross-sectional view including the width direction and depth direction of the sipe 60).

[0057] Furthermore, the shoulder land portion 25 has a tread sidewall 26 which is the end face of the tread portion 2 in the tire width direction and the outer end face of the shoulder land portion 25 in the tire width direction. Since the shoulder land portion 25 is partitioned on both sides in the tire circumferential direction by the shoulder lug groove 45, the tread sidewall 26 which is the outer end face of the shoulder land portion 25 in the tire width direction is also partitioned on both sides in the tire circumferential direction by the shoulder lug groove 45.

[0058] The uneven portion 70 is formed adjacent to each other in the tire circumferential direction, with a recess 71 that is recessed inward in the tire width direction on the tread sidewall 26 and a convex portion 75 that is convex outward in the tire width direction on the tread sidewall 26. The uneven portion 70 is located on the tread sidewall 26 of each shoulder land portion 25, which are arranged in a row in the tire circumferential direction. In this embodiment, one uneven portion 70 is located on the tread sidewall 26 of each shoulder land portion 25. In addition, for each uneven portion 70 located on the tread sidewall 26 of the shoulder land portion 25, the recess 71 is positioned on the side that makes contact with the convex portion 75 in the tire rotation direction.

[0059] Figure 3 is a schematic perspective view of the shoulder land portion 25 as seen from the tread sidewall 26 side. Figure 4 is a view of Figure 3 from the direction of arrow BB. Note that Figures 3 and 4 are mainly used to explain the uneven portion 70, so the shoulder grooves 55 and sipes 60 are not shown. The recesses 71 of the uneven portion 70 located on the tread sidewall 26 extend inward in the tire radial direction along the tread contact surface 3 and the tread sidewall 26, and are formed to be recessed inward in the tire width direction from the tread sidewall 26. The protrusions 75 of the uneven portion 70 extend inward in the tire radial direction along the tread contact surface 3 and the tread sidewall 26, and are formed to be convex outward in the tire width direction from the tread sidewall 26.

[0060] Since the uneven portion 70 extends radially inward along the tread sidewall 26 from the tread contact surface 3 of the shoulder land portion 25, it is formed to include a widthwise outer edge portion 27, which is an edge portion located at the boundary between the tread contact surface 3 and the tread sidewall 26 of the shoulder land portion 25.

[0061] Furthermore, the recessed portion 71 formed by recessing from the tread sidewall 26 and the convex portion 75 formed by protruding from the tread sidewall 26 in the uneven portion 70 are, in other words, formed by being recessed and convex with respect to a virtual line V connecting the ends 27a on both sides of the outer edge portion 27 in the tire circumferential direction. In this case, the ends 27a of the outer edge portion 27 in the width direction are the ends 27a of the outer edge portion 27 in the width direction that are located at the point where the outer edge portion 27 in the width direction intersects with the shoulder lug groove 45. The recessed portion 71 of the uneven portion 70 is formed by recessing inward in the tire width direction with respect to a straight virtual line V connecting the ends 27a on both sides of the outer edge portion 27 in the width direction, and the convex portion 75 of the uneven portion 70 is formed by protruding outward in the tire width direction with respect to the said virtual line V.

[0062] Furthermore, the recesses 71 in the uneven portion 70 are formed such that their depth from the tread sidewall 26 gradually changes in the tire circumferential direction. Specifically, within the range in the tire circumferential direction where the recesses 71 are located, there is a deepest portion 73, which is the deepest part of the recess 71 from the tread sidewall 26, and the depth from the tread sidewall 26 becomes shallower as you move away from the deepest portion 73 in the tire circumferential direction.

[0063] Furthermore, the protrusions 75 of the uneven portion 70 are formed so that their width in the tire circumferential direction narrows as they move away from the tread sidewall 26 toward the outside in the tire width direction, and have a vertex 77 at the position furthest outward from the tread sidewall 26 in the tire width direction. For this reason, the shape of the protrusions 75 when viewed in the tire radial direction, or the shape of the shoulder land portion 25 in plan view, is formed in a substantially triangular shape.

[0064] The uneven portion 70 having recesses 71 and protrusions 75 formed in this manner has the recesses 71 and protrusions 75 formed continuously in the tire circumferential direction. Furthermore, the recesses 71 and protrusions 75 of the uneven portion 70 are formed to have the same length in the sidewall direction, which is perpendicular to the tire circumferential direction and along the tread sidewall 26 on which the uneven portion 70 is positioned.

[0065] The uneven portion 70 is formed such that the recessed portion 71 and the convex portion 75 are continuously formed in the circumferential direction of the tire, and the lengths of the recessed portion 71 and the convex portion 75 in the side wall direction are the same. Therefore, the uneven portion 70 has a continuous wall surface 78 where the wall surface 72 of the recessed portion 71 and the wall surface 76 of the convex portion 75 are continuous. The continuous wall surface 78 is formed by continuously forming the portion of the wall surface 72 of the wall surface 72 of the recessed portion 71 that is located on the side of the convex portion 75 from the deepest part 73 and the portion of the wall surface 76 of the convex portion 75 that is located on the side of the recessed portion 71, and the wall surface 72 of the recessed portion 71 and the wall surface 76 of the convex portion 75 are continuous and form a single planar shape.

[0066] In this embodiment, the recessed portion 70 is located on the leading side in the tire rotation direction, and the convex portion 75 is located on the trailing side in the tire rotation direction. Therefore, the continuous wall surface 78 formed by the wall surface 72 of the recessed portion 71 and the wall surface 76 of the convex portion 75 is formed facing the portion closer to the leading side in the tire rotation direction.

[0067] The uneven portion 70 having the continuous wall surface 78 formed in this way has an inclination angle α of the continuous wall surface 78 with respect to the tread sidewall 26 that is within the range of 45° ≤ α ≤ 90°. Preferably, the inclination angle α of the continuous wall surface 78 with respect to the tread sidewall 26 is within the range of 55° ≤ α ≤ 80°.

[0068] Furthermore, the length La of the uneven portion 70 in the tire circumferential direction is 25% or more of the length Lb of the tread sidewall 26 on which the uneven portion 70 is located in the tire circumferential direction.

[0069] Figure 5 is a cross-sectional view of CC in Figure 2. Figure 6 is a view from arrow BB in Figure 3 and is an explanatory diagram of the dimensions of each part of the uneven portion 70. The recess 71 of the uneven portion 70 has a relationship between the depth Da of the recess 71 at the deepest part 73, which is the deepest part of the recess 71 from the tread side wall 26, and the groove depth Db of the shoulder lug groove 45, which is the lug groove 40 that demarcates the shoulder land portion 25, within the range of 0.35 ≤ Da / Db ≤ 0.55. In this case, the groove depth Db of the shoulder lug groove 45 is the distance from the outer edge portion 27 in the width direction to the groove bottom 45a of the shoulder lug groove 45 on the perpendicular Q when a perpendicular Q is drawn from the outer edge portion 27 in the width direction of the shoulder land portion 25 toward the inner surface 18 of the tire.

[0070] Furthermore, it is preferable that the relationship between the depth Da at the deepest part 73 of the recess 71 and the groove depth Db of the shoulder lug groove 45 is within the range of 0.4 ≤ Da / Db ≤ 0.5.

[0071] In the tread sidewall 26, the recessed portion 71 and the protruding portion 75 are formed with the same length in the sidewall direction, and the relationship between the length L3 of the recessed portion 70 in the sidewall direction (see Figure 3) and the length L4 of the tread sidewall 26 in the sidewall direction is within the range of 0.5 ≤ L3 / L4 ≤ 0.9. In this case, the length L4 of the tread sidewall 26 in the sidewall direction is the distance along the sidewall direction from the widthwise outer edge portion 27 of the shoulder land portion 25 to the groove bottom 45a of the shoulder lug groove 45 at the opening to the tread sidewall 26 in the shoulder lug groove 45.

[0072] Furthermore, the relationship between the height L5 of the protrusion 75 from the tread sidewall 26 and the depth Da at the deepest part 73 of the recess 71 is within the range of 0.5 ≤ L5 / Da ≤ 0.8. It is preferable that the sum of the height L5 of the protrusion 75 from the tread sidewall 26 and the depth Da at the deepest part 73 of the recess 71, L5+Da, is within the range of 3 mm to 15 mm. Also, it is preferable that the sum of the height L5 of the protrusion 75 from the tread sidewall 26 and the depth Da at the deepest part 73 of the recess 71, L5+Da, is within the range of 0.1 ≤ (L5+Da) / L1 ≤ 0.5 with respect to the width L1 of the shoulder land portion 25 in the tire width direction (see Figure 7).

[0073] Furthermore, the length Ld of the recess 71 in the uneven portion 70, from the end of the recess 71 on the side where the convex portion 75 is located in the tire circumferential direction to the deepest part 73, is within the range of 0.1 ≤ Ld / Lc ≤ 0.5 with respect to the length Lc of the recess 71 in the tire circumferential direction.

[0074] Figure 7 is a plan view of the shoulder land portion 25 shown in Figure 2, and is an explanatory diagram showing the positional relationship of the uneven portion 70 with respect to the sipe 60. In this embodiment, the shoulder land portion 25 on which the uneven portion 70 is arranged satisfies the relationship between the width L1 of the shoulder land portion 25 in the tire width direction and the length L2 of the tread side wall 26 in the tire circumferential direction, where L2 / L1 < 1.2. One uneven portion 70 is arranged for each tread side wall 26 of the shoulder land portion 25 formed in this way.

[0075] In the shoulder land area 25 where the uneven portion 70 is arranged, multiple sipes 60 extending in the tire width direction are arranged in the circumferential direction of the tire on the tread contact surface 3. The uneven portion 70 arranged on the tread side wall 26 has a recess 71 whose deepest part 73 is located in the circumferential direction of the tire between the sipe 60a, which is the furthest rearmost sipe in the tire rotation direction, and the sipe 60b adjacent to sipe 60a in the tire rotation direction, which is the first sipe to sipe 60a in the tire rotation direction, among the multiple sipes 60 arranged on the tread contact surface 3 of the shoulder land area 25.

[0076] When mounting the pneumatic tire 1 according to this embodiment onto a vehicle, the pneumatic tire 1 is assembled onto a rim wheel, and then inflated by filling it with air before mounting it to the vehicle. At that time, since the pneumatic tire 1 according to this embodiment has a specified mounting direction and rotation direction relative to the vehicle, it is mounted to the vehicle in the specified direction. That is, it is mounted to the vehicle in the direction specified by the mounting direction indicator and rotation direction indicator attached to the sidewall portion 8. As a result, the pneumatic tire 1 is mounted to the vehicle in such a way that the side where the first inner lug groove 42a and the second inner lug groove 42b are located is on the inside in the vehicle mounting direction relative to the tire equatorial plane CL, the side where the circumferential narrow groove 50 is located is on the outside in the vehicle mounting direction, and the recess 71 of the uneven portion 70 is located on the leading side in the tire rotation direction relative to the convex portion 75.

[0077] When a vehicle equipped with a pneumatic tire 1 is driven, the pneumatic tire 1 rotates while the lower part of the tread contact surface 3 of the tread section 2 is in contact with the road surface. When a vehicle equipped with a pneumatic tire 1 is driven on a dry road surface, it is driven mainly by the frictional force between the tread contact surface 3 and the road surface, which transmits driving force and braking force to the road surface and generates turning force.

[0078] Furthermore, when driving on a wet road surface, water between the tread contact surface 3 and the road surface enters grooves such as the circumferential main grooves 30 and lug grooves 40, as well as sipes 60, and these grooves drain the water between the tread contact surface 3 and the road surface as the vehicle drives. As a result, the tread contact surface 3 makes contact with the road surface more easily, and the frictional force between the tread contact surface 3 and the road surface allows the vehicle to drive.

[0079] Furthermore, when driving on a snowy road surface, the pneumatic tire 1 compresses the snow on the road surface with its tread contact surface 3, and the snow on the road surface enters the circumferential main grooves 30 and lug grooves 40, compressing these snow grooves as well. In this state, when driving force or braking force is applied to the pneumatic tire 1, or when a force is applied in the tire width direction due to the vehicle turning, a shear force, known as snow column shear force, is generated between the pneumatic tire 1 and the snow. When driving on a snowy road surface, this snow column shear force creates resistance between the pneumatic tire 1 and the road surface, allowing driving force and braking force to be transmitted to the road surface and ensuring snow traction. As a result, the vehicle can drive on snowy road surfaces.

[0080] Furthermore, when driving on snowy or icy surfaces, the edge effect of the circumferential main grooves 30, lug grooves 40, and sipes 60 is also utilized. In other words, when driving on snowy or icy surfaces, the resistance created by the edges of the circumferential main grooves 30, lug grooves 40, and sipes 60 catching on the snow or ice surface is also utilized. Additionally, when driving on icy surfaces, the sipes 60 absorb water from the surface of the icy surface, removing the water film between the icy surface and the tread contact surface 3, thereby making it easier for the icy surface and the tread contact surface 3 to make contact. As a result, the tread contact surface 3 experiences increased resistance with the icy surface due to friction and edge effect, ensuring the driving performance of the vehicle equipped with the pneumatic tire 1.

[0081] The circumferential main grooves 30, lug grooves 40, and sipes 60 formed on the tread portion 2 contribute to ensuring driving performance when driving on wet, snowy, or icy surfaces. For example, to improve wet performance, it is effective to increase the groove area ratio of the tread portion 2. In other words, by increasing the groove area ratio, which is the ratio of the area of ​​grooves such as the circumferential main grooves 30 and lug grooves 40 in the contact area, water on the road surface can easily enter the grooves when driving on a wet surface. This improves the drainage of water between the tread contact surface 3 and the road surface, thereby improving wet performance.

[0082] Furthermore, increasing the groove area ratio is also effective in improving snow performance, which is the driving performance on snowy roads. In other words, by increasing the groove area ratio, the amount of snow that can enter the circumferential main grooves 30 and lug grooves 40 when driving on snowy roads can be increased, and the snow column shear force acting on the snow that has entered the grooves can be increased. This improves snow traction when driving on snowy roads and thus improves snow performance.

[0083] When a vehicle drives on a snowy road, the weight of the vehicle causes the pneumatic tire 1 to sink into the snow on the road surface. As a result, the pneumatic tire 1 comes into contact with the snow on the road surface not only at the tread contact surface 3, but also at the sides of the tread portion 2 in the tire width direction. In other words, when a vehicle drives on a snowy road, the lower part of the tread sidewall 26, which is the side of the tread portion 2 in the tire width direction, also comes into contact with the snow on the road surface.

[0084] In this embodiment, the pneumatic tire 1 has a tread sidewall 26 that contacts the snow on the road surface when driving on a snowy road surface, and a recessed portion 71 and a convex portion 75 are arranged adjacent to each other in the circumferential direction of the tire. Therefore, when the tread sidewall 26 contacts the snow on the road surface, the recessed portion 70 contacts the snow, thereby increasing the frictional resistance between the pneumatic tire 1 and the snow on the road surface.

[0085] In other words, when the tread sidewall 26 contacts the snow, the protrusions 75 of the uneven surface 70 contact the snow on the road surface in the direction of rotation of the pneumatic tire 1. As a result, relative resistance in the direction of rotation of the pneumatic tire 1 is generated between the snow on the road surface and the protrusions 75. This makes it easier to transmit the driving force and braking force of the vehicle to the snow surface when driving on a snowy road. In addition, it can increase the resistance between the pneumatic tire 1 and the snowy road surface when the vehicle turns, thereby improving snow performance.

[0086] The protrusion 75, in this way, provides resistance in the rotational direction against the snow on the road surface when the pneumatic tire 1 rotates, thereby improving snow performance. However, if the height of the protrusion 75 is increased to further improve snow performance, stress concentration is more likely to occur around the protrusion 75. In this case, the protrusion 75 is more likely to break off or uneven wear may occur due to stress concentration, leading to a decrease in durability.

[0087] In contrast, in the pneumatic tire 1 according to this embodiment, the uneven portion 70 arranged on the tread sidewall 26 has not only a convex portion 75 but also a concave portion 71 adjacent to the convex portion 75 in the circumferential direction of the tire. Therefore, when the tread sidewall 26 comes into contact with snow on the road surface, the uneven portion 70 can cause snow to enter the concave portion 71, and relative resistance in the rotational direction of the pneumatic tire 1 can be generated between the snow that has entered the concave portion 71 and the snow. As a result, relative resistance in the rotational direction of the pneumatic tire 1 can be generated between the snow on the road surface and the uneven portion 70 without making the height of the convex portion 75 unnecessarily high, thereby improving snow performance while suppressing the decrease in durability caused by increasing the height of the convex portion 75.

[0088] Furthermore, since the recesses 71 of the uneven portion 70 are formed with a gradually changing depth from the tread sidewall 26 in the tire circumferential direction, it is possible to suppress snow that has entered the recesses 71 from becoming clogged within them. As a result, snow that has entered the recesses 71 can be easily removed when the pneumatic tire 1 rotates, while new snow can be allowed to enter the recesses 71, continuously ensuring resistance with the snow as the pneumatic tire 1 rotates, thereby continuously improving snow performance.

[0089] Furthermore, since the uneven portion 70 has a continuous wall surface 78 formed by the wall surface 72 of the recessed portion 71 and the wall surface 76 of the convex portion 75, a long edge in a direction intersecting the tire rotation direction can be secured on the outer edge portion 27 in the width direction by the continuous wall surface 78. As a result, the edge formed by the continuous wall surface 78 can increase the frictional force against snowy and icy road surfaces, thereby improving snow and ice performance. As a result, the pneumatic tire 1 according to this embodiment can improve snow performance while ensuring durability.

[0090] Furthermore, since the recessed portion 70 is located on the leading side in the tire rotation direction relative to the convex portion 75, the continuous wall surface 78 of the uneven portion 70 can be positioned on the trailing side of the recessed portion 71 in the tire rotation direction, and the orientation of the continuous wall surface 78 can be set to face towards the leading side in the tire rotation direction. As a result, snow that enters the recessed portion 71 while the pneumatic tire 1 is traveling on a snowy road surface while rotating in the specified tire rotation direction can be received by the continuous wall surface 78 facing towards the leading side in the tire rotation direction, and the resistance of the tire in the tire rotation direction against the snow on the road surface can be more reliably increased by the continuous wall surface 78. As a result, snow performance can be more reliably improved.

[0091] Furthermore, since the length La of the uneven portion 70 in the tire circumferential direction is 25% or more of the length Lb of the tread sidewall 26 in the tire circumferential direction where the uneven portion 70 is located, the resistance against snow on the road surface can be effectively increased by the uneven portion 70. In other words, if the length La of the uneven portion 70 is less than 25% of the length Lb of the tread sidewall 26 where the uneven portion 70 is located, the length La of the uneven portion 70 in the tire circumferential direction is too short, making it difficult to effectively increase the resistance of the uneven portion 70 against snow on the road surface in the tire rotation direction or in the vehicle turning direction, even if the uneven portion 70 is provided on the tread sidewall 26.

[0092] In contrast, if the length La of the uneven portion 70 is 25% or more of the length Lb of the tread sidewall 26 on which the uneven portion 70 is located, providing the uneven portion 70, which has recesses 71 and protrusions 75, on the tread sidewall 26 effectively increases the resistance of the tire in the direction of rotation and the vehicle in the direction of turning against snow on the road surface. As a result, snow performance can be improved more reliably.

[0093] Furthermore, the relationship between the depth Da at the deepest part 73 of the recess 71, which is the deepest part from the tread sidewall 26, and the groove depth Db of the shoulder lug groove 45 is within the range of 0.35 ≤ Da / Db ≤ 0.55, thus ensuring durability more reliably while improving snow performance.

[0094] In other words, if the relationship between the depth Da of the deepest part 73 of the recess 71 and the groove depth Db of the shoulder lug groove 45 is Da / Db < 0.35, then the depth Da of the deepest part 73 of the recess 71 is too shallow. As a result, even if a recess 71 is provided in the tread sidewall 26, it will not be possible to allow much snow to enter the recess 71, and it may become difficult to increase the resistance to snow on the road surface in the direction of tire rotation and the direction of vehicle turning. Furthermore, if the depth Da of the deepest part 73 of the recess 71 is too shallow, even if a recess 71 is provided in the tread sidewall 26, it will be difficult to effectively increase the edge length of the outer edge portion 27 in the width direction. As a result, it may become difficult to increase the frictional force against snowy or icy road surfaces by lengthening the outer edge portion 27 in the width direction. Furthermore, if the relationship between the depth Da of the deepest part 73 of the recess 71 and the groove depth Db of the shoulder lug groove 45 is Da / Db > 0.55, the depth Da of the deepest part 73 of the recess 71 is too deep, which may easily reduce the rigidity of the shoulder land portion 25 where the uneven portion 70 is located. In this case, the reduced rigidity of the shoulder land portion 25 may easily lead to premature wear or uneven wear, which may reduce durability.

[0095] In contrast, if the relationship between the depth Da of the deepest part 73 of the recess 71 and the groove depth Db of the shoulder lug groove 45 is within the range of 0.35 ≤ Da / Db ≤ 0.55, it is possible to maintain the depth of the recess 71 while suppressing the decrease in rigidity of the shoulder land portion 25. This allows more snow to enter the recess 71, increasing resistance to snow on the road surface in the tire rotation direction and the vehicle's turning direction, and also increases the frictional force against snowy and icy road surfaces by lengthening the outer edge portion 27 in the width direction. As a result, snow performance can be improved while more reliably ensuring durability.

[0096] Furthermore, the relationship between the length L3 of the uneven portion 70 in the sidewall direction and the length L4 of the tread sidewall 26 in the sidewall direction is within the range of 0.5 ≤ L3 / L4 ≤ 0.9, which allows for improved snow performance while ensuring greater durability. In other words, if the relationship between the length L3 of the uneven portion 70 in the sidewall direction and the length L4 of the tread sidewall 26 in the sidewall direction is L3 / L4 < 0.5, the length L3 of the uneven portion 70 is too short compared to the length L4 of the tread sidewall 26, which may make it difficult for snow to come into contact with the uneven portion 70 when driving on a snowy road surface. In this case, even if the uneven portion 70 is provided on the tread sidewall 26, it may be difficult to increase the resistance of the tire in the direction of rotation and the turning direction of the vehicle against snow on the road surface by the uneven portion 70. Furthermore, if the relationship between the length L3 of the uneven portion 70 in the sidewall direction and the length L4 of the tread sidewall 26 in the sidewall direction is L3 / L4 > 0.9, the length L3 of the uneven portion 70 is too long relative to the length L4 of the tread sidewall 26, which may easily reduce the rigidity of the shoulder land area 25 where the uneven portion 70 is located. In this case, the reduced rigidity of the shoulder land area 25 may easily lead to premature wear and uneven wear, which may reduce durability.

[0097] In contrast, if the relationship between the length L3 of the uneven portion 70 in the sidewall direction and the length L4 of the tread sidewall 26 in the sidewall direction is within the range of 0.5 ≤ L3 / L4 ≤ 0.9, then the reduction in rigidity of the shoulder land portion 25 can be suppressed while ensuring the length L3 of the uneven portion 70 in the sidewall direction, thereby increasing the resistance of the tire to snow on the road surface in the direction of tire rotation and the direction of vehicle turning due to the uneven portion 70. As a result, snow performance can be improved while more reliably ensuring durability.

[0098] Furthermore, the relationship between the height L5 of the protrusion 75 from the tread sidewall 26 and the depth Da at the deepest part 73 of the recess 71 is within the range of 0.5 ≤ L5 / Da ≤ 0.8, thus ensuring greater durability while improving snow performance. In other words, if the relationship between the height L5 of the protrusion 75 and the depth Da at the deepest part 73 of the recess 71 is L5 / Da < 0.5, the height L5 of the protrusion 75 is too low, and even if the protrusion 75 is provided on the tread sidewall 26, it may be difficult to effectively increase the resistance of the tire in the direction of rotation and the vehicle in the direction of turning against snow on the road surface with the protrusion 75. Furthermore, if the relationship between the height L5 of the protrusion 75 and the depth Da at the deepest part 73 of the recess 71 is L5 / Da > 0.8, the height L5 of the protrusion 75 is too high, which makes it easier for stress concentration to occur near the protrusion 75, potentially leading to breakage of the protrusion 75 or uneven wear due to stress concentration.

[0099] In contrast, if the relationship between the height L5 of the protrusion 75 and the depth Da at the deepest part 73 of the recess 71 is within the range of 0.5 ≤ L5 / Da ≤ 0.8, then the height L5 of the protrusion 75 can be maintained while suppressing the occurrence of breakage or uneven wear of the protrusion 75 due to stress concentration near the protrusion 75. This allows the protrusion 75 to increase resistance to snow on the road surface in the direction of tire rotation and vehicle turning. As a result, snow performance can be improved while more reliably ensuring durability.

[0100] Furthermore, the uneven portion 70 can more reliably improve snow performance because the inclination angle α of the continuous wall surface 78 with respect to the tread sidewall 26 is within the range of 45° ≤ α ≤ 90°. In other words, if the inclination angle α of the continuous wall surface 78 with respect to the tread sidewall 26 is α < 45°, the inclination angle α of the continuous wall surface 78 is too small, making it difficult to secure the edge component of the outer edge portion 27 in the width direction relative to the tire rotation direction by the continuous wall surface 78, which may make it difficult to increase the frictional force in the tire rotation direction relative to snowy or icy road surfaces. Also, if the inclination angle α of the continuous wall surface 78 with respect to the tread sidewall 26 is α > 90°, the inclination angle α of the continuous wall surface 78 is too large, which may make it difficult to secure the edge component of the outer edge portion 27 in the width direction relative to the continuous wall surface 78 when the vehicle is turning. In this case, there is a risk that the frictional force when a vehicle turns on a snowy or icy road surface will be difficult to increase due to the edge component of the continuous wall surface 78.

[0101] In contrast, if the inclination angle α of the continuous wall surface 78 relative to the tread sidewall 26 is within the range of 45° ≤ α ≤ 90°, the edge component of the widthwise outer edge portion 27 from the straight-ahead state to the turning state of the vehicle can be secured by the continuous wall surface 78, thereby increasing the frictional force against snowy or icy road surfaces. As a result, snow performance can be improved more reliably.

[0102] Furthermore, the relationship between the width L1 of the shoulder land portion 25 in the tire width direction and the length L2 of the tread sidewall 26 in the tire circumferential direction satisfies L2 / L1 < 1.2, and since one uneven portion 70 is placed on each tread sidewall 26, it is possible to suppress the excessive placement of uneven portions 70 on the tread sidewall 26 of the shoulder land portion 25. This suppresses the reduction in rigidity of the shoulder land portion 25 caused by placing the uneven portions 70 on the tread sidewall 26, and the resistance of the uneven portions 70 to snow on the road surface in the direction of tire rotation and vehicle turning can be increased. As a result, snow performance can be improved while more reliably ensuring durability.

[0103] Furthermore, the deepest part 73 of the recessed portion 71 of the uneven portion 70, which is the deepest part from the tread sidewall 26, is located in the tire circumferential direction between the sipe 60a, which is the furthest rearward-facing sipe in the tire rotation direction, and the sipe 60b, which is adjacent to sipe 60a in the tire circumferential direction and is on the frontward-facing side in the tire rotation direction, among the multiple sipes 60 arranged on the shoulder land portion 25. As a result, the recessed portion 71 of the uneven portion 70 can be positioned in an appropriate location in the tire circumferential direction relative to the tread sidewall 26 of the shoulder land portion 25, ensuring the volume of the recessed portion 71 recessed from the tread sidewall 26, and appropriately increasing the edge component of the widthwise outer edge portion 27 by the uneven portion 70. Consequently, the resistance to snow on the road surface in the tire rotation direction and the vehicle turning direction can be more reliably increased by the uneven portion 70. As a result, snow performance can be more reliably improved.

[0104] [Differentiation] In the embodiment described above, one tread side wall 26 of the shoulder land portion 25 has one uneven portion 70, but there may be multiple uneven portions 70 arranged on one tread side wall 26.

[0105] Figure 8 is an explanatory diagram showing a modified example of the pneumatic tire 1 according to the embodiment, in which two recessed portions 70 are arranged on one tread sidewall 26 of the shoulder land portion 25. The recessed portions 70 arranged on one tread sidewall 26 may, for example, be arranged side by side in the tire circumferential direction on one tread sidewall 26 of the shoulder land portion 25, as shown in Figure 8, if the relationship between the width L1 of the shoulder land portion 25 in the tire width direction and the length L2 of the tread sidewall 26 in the tire circumferential direction satisfies L2 / L1 ≥ 1.2. When two recessed portions 70 are arranged on one tread sidewall 26, it is preferable that both recessed portions 70 are arranged such that the recessed portion 71 is positioned towards the leading side in the tire rotation direction relative to the convex portion 75.

[0106] Furthermore, when two recessed portions 70 are arranged on a single tread sidewall 26, it is preferable that the recessed portion 70 located on the rearward side in the tire rotation direction has its deepest portion 73 in the recess 71 positioned in the tire circumferential direction between the sipe 60a, which is located on the rearward side in the tire rotation direction among the multiple sipes 60 arranged on the shoulder land portion 25, and the sipe 60b adjacent to sipe 60a in the tire circumferential direction.

[0107] Furthermore, when two protrusions 70 are arranged on a single tread sidewall 26 in this manner, it is preferable that the sum of the lengths La (see Figure 4) of each protrusion 70 in the tire circumferential direction is 50% or more of the length Lb of the tread sidewall 26 on which the protrusions 70 are arranged in the tire circumferential direction.

[0108] As described above, when the relationship between the width L1 in the tire width direction and the length L2 in the tire circumferential direction of the shoulder land portion 25 satisfies L2 / L1 ≥ 1.2, two uneven portions 70 are arranged side by side in the tire circumferential direction on one tread side wall 26 of the shoulder land portion 25, thereby allowing for appropriate placement of the uneven portions 70 for shoulder land portions 25 with a longer length in the tire circumferential direction. In other words, by arranging two uneven portions 70 side by side in the tire circumferential direction on the tread side wall 26 of a shoulder land portion 25 with a longer length in the tire circumferential direction, the area in the tire circumferential direction where the uneven portions 70 are not arranged on the tread side wall 26 can be reduced, and more uneven portions 70 can be arranged on the tread side wall 26. As a result, in shoulder land portions 25 with a longer length in the tire circumferential direction, the two uneven portions 70 arranged on the tread side wall 26 can more reliably increase the resistance to snow on the road surface in the tire rotation direction and the vehicle turning direction. As a result, snow performance can be more reliably improved.

[0109] Furthermore, of the two uneven portions 70, the uneven portion 70 located on the leading side in the tire rotation direction has its deepest part 73 in the recess 71 positioned between the sipe 60c located on the leading side in the tire rotation direction and the sipe 60d adjacent to sipe 60c in the tire rotation direction among the multiple sipes 60 arranged on the shoulder land portion 25. This allows the uneven portion 70 located on the leading side in the tire rotation direction to be positioned appropriately in the tire rotation direction relative to the tread sidewall 26 of the shoulder land portion 25. As a result, there are no areas on the tread sidewall 26 where the uneven portion 70 is not positioned towards the leading side in the tire rotation direction, and the uneven portion 70 can be positioned towards the leading side in the tire rotation direction. Therefore, the resistance to snow on the road surface in the tire rotation direction and the vehicle turning direction can be more reliably increased by the two uneven portions 70. As a result, snow performance can be more reliably improved.

[0110] Furthermore, in the embodiment described above, the shoulder land portion 25 is a block-shaped land portion 20 because the inner end in the tire width direction of the shoulder lug groove 45 that defines the shoulder land portion 25 opens into the outer circumferential main groove 35. However, the shoulder land portion 25 may be formed in a shape other than a block shape. For example, the shoulder land portion 25 may be a rib-shaped land portion 20 that is continuous in the tire circumferential direction, because the outer end in the tire width direction of the shoulder lug groove 45 that defines the shoulder land portion 25 opens toward the outer side of the tread portion 2 in the tire width direction, and the inner end in the tire width direction of the shoulder lug groove 45 terminates within the shoulder land portion 25. Regardless of the shape of the shoulder land portion 25 on which the uneven portion 70 is arranged, it is sufficient that both sides in the tire circumferential direction of the tread side wall 26 on which the uneven portion 70 is arranged are defined by the lug groove 40.

[0111] Furthermore, in the above-described embodiment, there are five circumferential main grooves 30 arranged in the tread portion 2, but the number of circumferential main grooves 30 may be other than five. Also, the above-described embodiments and modifications may be combined as appropriate. In addition, in the above-described embodiment, a pneumatic tire 1 was used as an example of a tire according to the present invention, but the tire according to the present invention may be other than a pneumatic tire 1. The tire according to the present invention may be, for example, a so-called airless tire that can be used without filling with gas.

[0112] [Examples] Figures 9A and 9B are charts showing the results of performance evaluation tests for pneumatic tires. Below, we will describe the performance evaluation tests conducted on the above-mentioned pneumatic tire 1, comparing it with a conventional pneumatic tire, the pneumatic tire 1 according to the present invention, and a comparative example pneumatic tire used for comparison with the pneumatic tire 1 according to the present invention. The performance evaluation tests focused on snow turning performance and durability.

[0113] The performance evaluation test was conducted by mounting a pneumatic tire (size 195 / 65R15 91Q as defined by JATMA) onto a JATMA standard rim wheel with a rim size of 15×6.5J, and then mounting the test tire on a front-wheel-drive evaluation vehicle with an engine displacement of 1800cc, adjusting the air pressure to 240kPa, and driving the evaluation vehicle.

[0114] For each test item, the evaluation method for snow cornering performance involved conducting cornering tests on a snow-covered test course using an evaluation vehicle equipped with test tires. The reciprocal of the cornering time during the cornering test was expressed as an index with the conventional example described later set to 100. A higher index indicates better cornering ability on snow-covered surfaces and superior driving performance on snow-covered surfaces.

[0115] Furthermore, regarding durability, the occurrence of breakage on the shoulder area 25 was visually measured after an evaluation vehicle equipped with the test tire had traveled 10,000 km. Durability is expressed as an index with the occurrence of breakage on the shoulder area 25 set to 100 (as described later for conventional examples). A higher value indicates less breakage on the shoulder area 25 and superior durability.

[0116] Performance evaluation tests were conducted on 20 types of pneumatic tires, including a conventional pneumatic tire (an example of a conventional pneumatic tire), Examples 1 to 17 (pneumatic tire 1 according to the present invention), and Comparative Examples 1 and 2 (pneumatic tires compared to pneumatic tire 1 according to the present invention). Of these, the conventional example does not have convex and concave portions on the tread sidewall of the shoulder land area. Comparative Example 1 has convex portions on the tread sidewall but no concave portions. Comparative Example 2 has convex and concave portions on the tread sidewall, but the convex and concave portions do not have a continuous wall surface.

[0117] In contrast, in all of the examples of the pneumatic tire 1 according to the present invention, the uneven portion 70 having a convex portion 75 and a concave portion 71, as well as a continuous wall surface 78, is arranged on the tread side wall 26 of the shoulder land portion 25. Furthermore, the pneumatic tire 1 according to Examples 1 to 17 differs in the following aspects: whether the recess 71 of the uneven portion 70 is located on the leading side in the tire rotation direction relative to the convex portion 75; the length La of the uneven portion 70 in the tire circumferential direction relative to the length Lb of the tread sidewall 26 in the tire circumferential direction; the depth Da at the position of the deepest part 73 of the recess 71 relative to the groove depth Db of the shoulder lug groove 45; the length L3 of the uneven portion 70 in the sidewall direction relative to the length L4 of the tread sidewall 26 in the sidewall direction; the height L5 of the convex portion 75 relative to the depth Da at the deepest part 73 of the recess 71; the inclination angle α of the continuous wall surface 78 relative to the tread sidewall 26; and whether the position of the deepest part 73 of the recess 71 in the tire circumferential direction is located between the sipe 60a, which is located on the rearmost side in the tire rotation direction, and the sipe 60b adjacent to the sipe 60a in the tire circumferential direction.

[0118] Performance evaluation tests were conducted using these pneumatic tires 1, and as shown in Figures 9A and 9B, it was found that the pneumatic tires 1 according to Examples 1 to 17 can improve snow turning performance without reducing durability compared to the conventional example and Comparative Examples 1 and 2. In other words, the pneumatic tires 1 according to Examples 1 to 17 can improve snow performance while ensuring durability.

[0119] This disclosure encompasses the following inventions: Invention [1] On the tread, Multiple circumferential main grooves extending in the circumferential direction of the tire, Multiple lug grooves extending in the width direction of the tire, Multiple land areas are demarcated by the circumferential main groove and the lug groove, Equipped with, Of the multiple land portions, the shoulder land portion, which is the outermost land portion in the tire width direction, has a tread side wall that is the end face of the tread portion in the tire width direction and is partitioned on both sides in the tire circumferential direction by the lug grooves, and has a recess that extends inward in the tire radial direction along the tread side wall from the tread contact surface and recesses inward in the tire width direction, and a convex portion that extends inward in the tire radial direction along the tread side wall from the tread contact surface and convex outward in the tire width direction, and has adjacent concave and concave portions in the tire circumferential direction. The recess is formed such that its depth from the tread sidewall gradually changes in the circumferential direction of the tire. The tire is characterized in that the uneven portion has a continuous wall surface formed by the wall surface of the recess and the wall surface of the protrusion. invention[2] It is equipped with a display unit that specifies the direction of tire rotation, The tire according to invention [1], wherein the recessed portion is located on the side of the convex portion that is first to arrive in the tire rotation direction. Invention [3] Multiple sipes extending in the tire width direction are arranged in the tire circumferential direction on the tread contact surface of the shoulder land portion. The tire according to invention [2], wherein the position in the tire circumferential direction of the deepest part of the recess from the tread side wall is located between the sipe that is located furthest back in the tire rotation direction and the sipe adjacent to that sipe in the tire circumferential direction among the plurality of sipes. invention [4] Multiple sipes extending in the tire width direction are arranged in the tire circumferential direction on the tread contact surface of the shoulder land portion. The aforementioned uneven portion is such that two of the uneven portions are arranged side by side in the tire circumferential direction on one of the tread sidewalls. The tire according to invention [2], wherein the uneven portion of the two uneven portions located on the leading side in the tire rotation direction is located in the tire circumferential direction at the position of the deepest part of the recess from the tread side wall between the sipe located on the leading side in the tire rotation direction and the sipe adjacent to that sipe in the tire circumferential direction. invention [5] The tire according to any one of the inventions [1] to [4], wherein the length La of the uneven portion in the tire circumferential direction is 25% or more of the length Lb of the tread side wall on which the uneven portion is arranged in the tire circumferential direction. invention [6] The tire according to any one of inventions [1] to [5], wherein the relationship between the depth Da of the recess at the deepest part from the tread sidewall and the groove depth Db of the lug groove that demarcates the shoulder land portion is within the range of 0.35 ≤ Da / Db ≤ 0.55. invention [7] The tire according to any one of inventions [1] to [6], wherein the uneven portion is in a direction perpendicular to the circumferential direction of the tire, and the relationship between the length L3 of the uneven portion in the sidewall direction, which is the direction along the tread sidewall where the uneven portion is arranged, and the length L4 of the tread sidewall in the sidewall direction is within the range of 0.5 ≤ L3 / L4 ≤ 0.9. invention [8] The tire according to any one of inventions [1] to [7], wherein the relationship between the height L5 of the protrusion from the tread sidewall and the depth Da of the recess at the deepest part of the recess from the tread sidewall is within the range of 0.5 ≤ L5 / Da ≤ 0.8. invention[9] The tire according to any one of inventions [1] to [8], wherein the inclination angle α of the continuous wall surface with respect to the tread side wall is in the range of 45° ≤ α ≤ 90°. Invention

[10] The shoulder land portion on which the aforementioned uneven portion is arranged satisfies the relationship between the width L1 of the shoulder land portion in the tire width direction and the length L2 of the tread side wall in the tire circumferential direction L2 / L1 < 1.2. The tire according to any one of the inventions [1] to [9], wherein one of the aforementioned uneven portions is arranged on one of the tread sidewalls. Invention

[11] The shoulder land portion on which the aforementioned uneven portion is arranged satisfies the relationship between the width L1 of the shoulder land portion in the tire width direction and the length L2 of the tread side wall in the tire circumferential direction, L2 / L1 ≥ 1.2. The tire according to any one of the inventions [1] to [9], wherein the uneven portion is arranged in the circumferential direction of the tire on one of the tread sidewalls, and two of the uneven portions are arranged side by side on the tread sidewall. [Explanation of Symbols]

[0120] 1. Pneumatic tire 2 Tread section 3. Tread contact surface 4 Tread Rubber 5 Shoulder section 8 Sidewall section 10 Bead section 11 Bead core 12 Bead Fillers 13. Carcass layer 14 Belt Layer 16 Inner liner 17 Rim cushion rubber 18 Tire interior 20 Land 21 Center Track and Field Club 22 Second Track and Field Club 25 Shoulder Track and Field Club 26 Tread sidewall 27 Outer edge portion in the width direction 30 Circumferential main groove 31 Center circumferential main groove 32 Inner circumferential main groove 35 Outer circumferential main groove 40 lug grooves 41 Center lug groove 42 Inner lug groove 44 Outer lug groove 45 Shoulder lug groove 50 Circumferential thin groove 55 Shoulder narrow groove 60 sipes 70 Uneven part 71 recess 72, 76 Wall surfaces 73 Deepest part 75 Convex part 77 Vertex 78 continuous wall surfaces

Claims

1. On the tread, Multiple circumferential main grooves extending in the circumferential direction of the tire, Multiple lug grooves extending in the width direction of the tire, Multiple land areas are demarcated by the circumferential main groove and the lug groove, Equipped with, Of the multiple land portions, the shoulder land portion, which is the outermost land portion in the tire width direction, has a tread side wall that is the end face of the tread portion in the tire width direction and is partitioned on both sides in the tire circumferential direction by the lug grooves, and has a recess that extends inward in the tire radial direction along the tread side wall from the tread contact surface and recesses inward in the tire width direction, and a convex portion that extends inward in the tire radial direction along the tread side wall from the tread contact surface and convex outward in the tire width direction, and has adjacent concave and concave portions in the tire circumferential direction. The recess is formed such that its depth from the tread sidewall gradually changes in the circumferential direction of the tire. The tire is characterized in that the uneven portion has a continuous wall surface formed by the wall surface of the recess and the wall surface of the protrusion.

2. It is equipped with a display unit that specifies the direction of tire rotation, The tire according to claim 1, wherein the recessed portion is located on the side of the convex portion that is first to arrive in the tire rotation direction.

3. Multiple sipes extending in the tire width direction are arranged in the tire circumferential direction on the tread contact surface of the shoulder land portion. The tire according to claim 2, wherein the position in the tire circumferential direction of the deepest part of the recess from the tread side wall is located between the sipe that is located furthest back in the tire rotation direction and the sipe adjacent to that sipe in the tire circumferential direction among the plurality of sipes.

4. Multiple sipes extending in the tire width direction are arranged in the tire circumferential direction on the tread contact surface of the shoulder land portion. The aforementioned uneven portion is such that two of the uneven portions are arranged side by side in the circumferential direction of the tire on one of the tread sidewalls. The tire according to claim 2, wherein the recessed portion located on the leading side in the tire rotation direction of the two recessed portions is located in the tire circumferential direction of the portion with the deepest depth from the tread sidewall in the recess, between the sipe located on the leading side in the tire rotation direction of the plurality of sipes and the sipe adjacent to that sipe in the tire circumferential direction.

5. The tire according to claim 1, wherein the length La of the uneven portion in the tire circumferential direction is 25% or more of the length Lb of the tread side wall on which the uneven portion is arranged in the tire circumferential direction.

6. The tire according to claim 1, wherein the relationship between the depth Da of the recess at its deepest point from the tread sidewall and the groove depth Db of the lug groove that demarcates the shoulder land portion is within the range of 0.35 ≤ Da / Db ≤ 0.

55.

7. The tire according to claim 1, wherein the uneven portion is in a direction perpendicular to the circumferential direction of the tire, and the relationship between the length L3 of the uneven portion in the sidewall direction, which is the direction along the tread sidewall where the uneven portion is arranged, and the length L4 of the tread sidewall in the sidewall direction is within the range of 0.5 ≤ L3 / L4 ≤ 0.

9.

8. The tire according to claim 1, wherein the relationship between the height L5 of the protrusion from the tread sidewall and the depth Da of the recess at the deepest part of the recess from the tread sidewall is within the range of 0.5 ≤ L5 / Da ≤ 0.

8.

9. The tire according to claim 1, wherein the inclination angle α of the continuous wall surface with respect to the tread side wall is within the range of 45° ≤ α ≤ 90°.

10. The shoulder land portion on which the aforementioned uneven portion is arranged satisfies the relationship between the width L1 of the shoulder land portion in the tire width direction and the length L2 of the tread side wall in the tire circumferential direction L2 / L1 < 1.

2. The tire according to claim 1, wherein one of the aforementioned uneven portions is arranged on one of the tread sidewalls.

11. The shoulder land portion on which the aforementioned uneven portion is arranged satisfies the relationship between the width L1 of the shoulder land portion in the tire width direction and the length L2 of the tread side wall in the tire circumferential direction L2 / L1 ≥ 1.

2. The tire according to claim 1, wherein two of the aforementioned uneven portions are arranged side by side in the circumferential direction of the tire on one of the tread sidewalls.

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