Tire

Abstract

To provide a tire that can improve mud performance and snow performance while maintaining maneuvering stability during travel in a straight line.SOLUTION: A tread part 2 of a tire is provided with a plurality of circumferential grooves 50 extending in a tire circumferential direction and a plurality of land parts 30 partitioned by the plurality of circumferential main grooves 50. A wavy part 40 formed over a tread ground plane 3 and a tread side wall 4, which is an end surface in a tire width direction of the tread part 2, is arranged in a shoulder land part 31, which is the land part 30 positioned on the outermost side in the tire width direction among the plurality of land parts 30. The wavy part 40 is formed over the tread ground plane 3 and the tread side wall 4 while oscillating due to alternate arrangement of a protrusion part 41 protruding to the tire outer side and a recess part 42 protruding to the tire inner side in a tire meridian cross section. A ground contact area side end part 43 as a connection part of the wavy part 40 with the tread ground surface 3 is positioned at a tire ground end T or on the outer side of tire grounding end T in the tire width direction.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a tire.

Background Art

[0002] The shoulder portions located at both ends in the tire width direction of the tread portion of a tire are also important parts for ensuring the performance of the tire during vehicle running. Therefore, among conventional tires, there are those that have various contrivances in the vicinity of the shoulder portions. For example, the pneumatic tire described in Patent Document 1 forms a stepped portion on the side wall on the tread end side of the shoulder block, thereby ensuring wandering resistance and lane change performance when running on a rut road surface.

[0003] Also, the heavy-duty pneumatic radial tire described in Patent Document 2 provides a narrow groove extending in the tire circumferential direction in the rib formed in the shoulder portion, and chamfers both edge portions of the outer rib outside the narrow groove into an arc shape in cross section, thereby improving the edge separation resistance of the belt layer. Further, the heavy-duty pneumatic tire described in Patent Document 3 provides an annular recess extending in the tire circumferential direction in the buttress portion, and provides an annular rib that divides the inside of the annular recess into a plurality of recesses to form an uneven shape, thereby preventing stress concentration on the shoulder portion and achieving low rolling resistance.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] Here, among tires, there is a category of tires called all-terrain tires. In all-terrain tires, various road surface performances such as dry performance, wet performance, mud performance, and snow performance are required. Therefore, for example, for the purpose of improving mud performance and snow performance, the groove area is often made relatively large. However, when the groove area is increased, the contact area with the ground becomes smaller, so there is a risk that the handling stability during straight running may relatively easily decrease. For this reason, it has been very difficult to achieve both the handling stability during straight running and the improvement of mud performance and snow performance.

[0006] The present invention has been made in view of the above, and an object thereof is to provide a tire capable of improving mud performance and snow performance while maintaining the handling stability during straight running.

Means for Solving the Problems

[0007] In order to solve the above-described problems and achieve the object, the tire according to the present invention includes, in a tread portion, a plurality of circumferential main grooves extending in the tire circumferential direction, and a plurality of land portions partitioned by the plurality of circumferential main grooves. Among the plurality of land portions, a shoulder land portion which is the land portion located most outside in the tire width direction has a wavy portion formed across the tread contact surface and a tread side wall which is an end surface of the tread portion in the tire width direction. The wavy portion is formed across the tread contact surface and the tread side wall while having an amplitude by alternately arranging convex portions that are convex toward the outside of the tire and concave portions that are convex toward the inner cavity side of the tire in a tire meridian cross section. The ground contact side end portion which is a connection portion of the wavy portion with the tread contact surface is located on the tire ground contact end or outside the tire width direction from the tire ground contact end.

[0008] Further, in the above tire, it is preferable that the wavy portion is formed as an arc convex to the outside of the tire, with a virtual chamfering line passing through the sidewall-side end portion, which is the connection portion between the wavy portion and the tread sidewall in the tire meridian section, and the ground contact side end portion and contacting at least one of the convex portions.

[0009] Further, in the above tire, it is preferable that the distance D1 from the tread end, which is the intersection of the extension line obtained by extending the profile of the tread ground contact surface to the outside in the tire width direction and the extension line obtained by extending the profile of the tread sidewall to the outside in the tire radial direction, to the virtual chamfering line satisfies the relationship of 0.3D ≦ D1 ≦ 0.5D with respect to the groove depth D of the circumferential main groove.

[0010] Further, in the above tire, it is preferable that the distance D2 from the virtual chamfering line to the bottom of the recess of the wavy portion satisfies the relationship of 0.5D1 ≦ D2 with respect to the distance D1 from the tread end to the virtual chamfering line.

[0011] Further, in the above tire, it is preferable that the respective distances D2 from the virtual chamfering line to the bottom of the recesses in the plurality of recesses of the wavy portion are 50% or more with respect to the distance D2 of the recess having the largest distance D2 from the virtual chamfering line to the bottom of the recess among the plurality of recesses.

[0012] Further, in the above tire, it is preferable that the wavy portion width direction distance W1, which is the distance from the tread end, which is the intersection of the extension line obtained by extending the profile of the tread ground contact surface to the outside in the tire width direction and the extension line obtained by extending the profile of the tread sidewall to the outside in the tire radial direction, to the ground contact side end portion, satisfies the relationship of 0.01W ≦ W1 ≦ 0.15W with respect to the tread width W, which is the width in the tire width direction of the outer peripheral surface of the tread portion.

[0013] Further, in the above tire, the wavy portion is a distance L1, which is the distance from the tread end, which is the intersection of the extension line obtained by extending the profile of the tread contact surface outward in the tire width direction and the extension line obtained by extending the profile of the tread sidewall outward in the tire radial direction, to the sidewall side end portion, which is the connection portion between the wavy portion and the tread sidewall in the tire meridian cross section. It is preferable that the relationship of 0.1L ≦ L1 ≦ 0.6L is satisfied with respect to the distance L from the tread end to the sector cut position portion.

[0014] Further, in the above tire, it is preferable that the wavy portion is formed continuously in the tire circumferential direction with respect to the shoulder land portion.

[0015] Further, in the above tire, a pair of intersecting belts are arranged inside the tread portion in the tire radial direction, and it is preferable that the width in the tire width direction of the intersecting belt on the outer side in the tire radial direction among the pair of intersecting belts is 101% or more with respect to the tire contact width.

[0016] Further, in the above tire, it is preferable that the number of the concave portions of the wavy portion is in the range of 2 or more and 6 or less, and the number of the convex portions is in the range of 1 or more and 5 or less.

[0017] Further, in the above tire, it is preferable that the concave portions and the convex portions of the wavy portion are each formed in an arc shape in the tire meridian cross section. [Effect of the Invention]

[0018] The tire according to the present invention has an effect that it can improve the mud performance and snow performance while maintaining the handling stability during straight running. [Brief Description of the Drawings]

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6A

Figure 6B

Mode for Carrying Out the Invention

[0020] Hereinafter, embodiments of the tire according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited by this embodiment. Further, 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] In the following description, the tire radial direction refers to the direction orthogonal to the tire rotation axis (not shown) which is the rotation axis of the pneumatic tire 1, the inner side in the tire radial direction refers to the side facing the tire rotation axis in the tire radial direction, and the outer side in the tire radial direction refers to the side away from the tire rotation axis in the tire radial direction. Also, the tire circumferential direction refers to the circumferential direction around the tire rotation axis as the central axis. Further, the tire width direction refers to the direction parallel to the tire rotation axis, the inner side in the tire width direction refers to the side facing the tire equatorial plane (tire equator line) CL in the tire width direction, and the outer side in 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 that is orthogonal to the tire rotation axis and passes through the center of the tire width of the pneumatic tire 1, and the tire equatorial plane CL coincides with the tire width direction center line which is the central position in the tire width direction of the pneumatic tire 1. The tire width is the width in the tire width direction between the outermost portions located in the tire width direction, that is, the distance between the portions that are farthest from the tire equatorial plane CL in the tire width direction. The tire equator line refers to a line on the tire equatorial plane CL and along the tire circumferential direction of the pneumatic tire 1. Also, in the following description, the tire meridian section refers to the section when the tire is cut by a plane including the tire rotation axis.

[0023] FIG. 1 is a tire meridian sectional view showing a main part of the pneumatic tire 1 according to the embodiment. FIG. 1 shows a pneumatic radial tire for a light truck as an example of the pneumatic tire 1 according to the present embodiment.

[0024] In the pneumatic tire 1 according to the present embodiment, when viewed in the tire meridian section, the tread portion 2 is disposed at the outermost portion in the tire radial direction, and the tread portion 2 has a tread rubber 6 made of a rubber composition. Also, the surface of the tread portion 2, that is, the portion that contacts the road surface when the vehicle (not shown) on which the pneumatic tire 1 is mounted travels, 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.

[0025] Shoulder portions 7 are located at both outer ends of the tread portion 2 in the tire width direction, and a sidewall portion 8 is disposed on the inner side in the tire radial direction of the shoulder portion 7. That is, the sidewall portion 8 is disposed on both sides in the tire width direction of the tread portion 2. In other words, the sidewall portion 8 is disposed at two positions on both sides in the tire width direction of the pneumatic tire 1, and forms the portion most exposed on the outermost side in the tire width direction of the pneumatic tire 1.

[0026] Bead portions 10 are located on the inner side in the tire radial direction of the respective sidewall portions 8 located on both sides in the tire width direction. The bead portions 10 are disposed at two positions on both sides of the tire equatorial plane CL, similar to the sidewall portions 8. That is, a pair of bead portions 10 are disposed on both sides in the tire width direction of the tire equatorial plane CL. Each bead portion 10 is provided with a bead core 11, and a bead filler 12 is provided on the outer side in the tire radial direction of the bead core 11. The bead core 11 is an annular member formed by bundling bead wires made of steel wire into an annular shape, and the bead filler 12 is a rubber member disposed on the outer side in the tire radial direction of the bead core 11.

[0027] Also, a belt layer 14 is disposed on the inner side in the tire radial direction of the tread portion 2. The belt layer 14 is configured by a multilayer structure in which a pair of intersecting belts 141, 142 and a plurality of belt covers 143, 144 are laminated. The pair of intersecting belts 141, 142 constituting the belt layer 14 are formed by coating a plurality of belt cords made of steel, or organic fiber materials such as polyester, rayon, and nylon, with coating rubber and performing rolling processing. The belt angle defined as the inclination angle of the belt cords with respect to the tire circumferential direction is within a predetermined range (for example, 15° or more and 55° or less). Also, the pair of intersecting belts 141, 142 have different belt angles. Therefore, the belt layer 14 is configured in a so-called cross ply structure in which the pair of intersecting belts 141, 142 are laminated with their belt cord inclination directions intersecting each other.

[0028] Further, the belt covers 143 and 144 are formed by coating a plurality of belt cover cords made of steel or organic fiber materials such as polyester, rayon, and nylon with a coating rubber and then performing rolling processing. The belt angle, which is 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 covers 143 and 144 are, for example, strip materials formed by coating one or a plurality of belt cover cords with a coating rubber, and this strip material is wound spirally around the outer side in the tire radial direction of the cross belts 141 and 142 with the tire rotation axis as the center. Further, the plurality of belt covers 143 and 144 are arranged to cover the entire area of the cross belts 141 and 142.

[0029] On the inner side in the tire radial direction of the belt layer 14 and on the tire equatorial plane CL side of the sidewall portion 8, a carcass layer 13 enclosing a radial ply cord is continuously provided. For this reason, the pneumatic tire 1 according to the present embodiment is configured as a so-called radial tire. The carcass layer 13 has a single-layer structure composed of one carcass ply or a multilayer structure formed by laminating a plurality of carcass plies, and is bridged toroidally between a pair of bead portions 10 arranged on both sides in the tire width direction to form the skeleton of the tire.

[0030] Specifically, the carcass layer 13 is disposed from one bead part 10 to the other bead part 10 among a pair of bead parts 10 located on both sides in the tire width direction, and is wound back outward in the tire width direction along the bead core 11 by the bead part 10 so as to wrap the bead core 11 and the bead filler 12. The bead filler 12 is a rubber material disposed in a space formed outside the bead core 11 in the tire radial direction when the carcass layer 13 is folded back by the bead part 10 in this way. Further, the belt layer 14 is disposed outside the tire radial direction of a portion located inside the tire radial direction of the tread part 2 in the carcass layer 13 spanned between the pair of bead parts 10 in this way. Further, the carcass ply of the carcass layer 13 is constituted by covering a plurality of carcass cords made of steel or organic fiber materials such as aramid, nylon, polyester, and rayon with a coat rubber and performing rolling processing. The carcass cords constituting the carcass ply are arranged in parallel in a plurality with an angle in the tire circumferential direction while the angle with respect to the tire circumferential direction is along the tire meridian direction.

[0031] 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 folded-back part of the carcass layer 13 in the bead part 10, a rim cushion rubber 17 that constitutes a contact surface of the bead part 10 with respect to the rim flange is disposed. Further, an inner liner 16 is formed along the carcass layer 13 inside the carcass layer 13 or on the inner side of the pneumatic tire 1 of the carcass layer 13. The inner liner 16 forms the tire inner surface 18 which is the inner surface of the pneumatic tire 1.

[0032] In the tread portion 2, a plurality of circumferential main grooves 50 extending in the tire circumferential direction are formed on the tread ground contact surface 3, and a plurality of land portions 30 are defined on the surface of the tread portion 2 by the plurality of circumferential main grooves 50. The circumferential main groove 50 is a groove having the display obligation of the wear indicator defined by JATMA. The circumferential main groove 50 has a groove width within the range of 5.0 mm or more and 10 mm or less, and a groove depth within the range of 8.0 mm or more and 15 mm or less. The circumferential main groove 50 may extend linearly along the tire circumferential direction, or may be formed in a zigzag shape by repeatedly bending or curving in the tire width direction while extending in the tire circumferential direction.

[0033] Among the plurality of land portions 30 defined by the circumferential main groove 50, the land portion 30 located on the outermost side in the tire width direction is the shoulder land portion 31. The shoulder land portion 31 is provided as the shoulder land portion 31 at both ends in the tire width direction among the plurality of land portions 30 defined by the circumferential main groove 50. That is, the inner portion of the shoulder land portion 31 in the tire width direction is defined by the outermost circumferential main groove 51 located on the outermost side in the tire width direction among the plurality of circumferential main grooves 50.

[0034] At least one of the shoulder land portions 31 located on both sides in the tire width direction is provided with a corrugated portion 40 formed across the tread ground contact surface 3 and the tread side wall 4. In this case, the tread ground contact surface 3 is the surface on the outer side in the tire radial direction of the tread portion 2. The tread side wall 4 is the end surface in the tire width direction of the tread portion 2, that is, the surface of the tread portion 2 facing the outer side in the tire width direction in the tread portion 2, and constitutes a so-called buttress portion. In the present embodiment, the corrugated portions 40 are respectively arranged on the shoulder land portions 31 on both sides in the tire width direction.

[0035] Figure 2 is a detailed view of part C in Figure 1. The corrugated portion 40 disposed on the shoulder land portion 31 is formed with convex portions 41 that protrude outward of the tire in the tire meridian cross-section and concave portions 42 that protrude toward the inner cavity side of the tire, alternately arranged so as to have an amplitude across the tread contact surface 3 and the tread sidewall 4. Specifically, the corrugated portion 40 is formed in a chamfered shape across the tread contact surface 3 and the tread sidewall 4 in the shoulder land portion 31, and the chamfered portion is formed in a shape with an amplitude where the convex portions 41 and the concave portions 42 are alternately arranged, for example, from the tread contact surface 3 side toward the tread sidewall 4 side.

[0036] The concave portion 42 and the convex portion 41 of the corrugated portion 40 are each formed in an arc shape in the tire meridian cross-section. That is, the corrugated portion 40 is formed in a wavy shape across the tread contact surface 3 and the tread sidewall 4 by alternately arranging the arc-shaped concave portion 42 and the arc-shaped convex portion 41 in the tire meridian cross-section.

[0037] In the corrugated portion 40, the number of concave portions 42 is within the range of 2 or more and 6 or less, and the number of convex portions 41 is within the range of 1 or more and 5 or less. In this embodiment, the corrugated portion 40 has 3 concave portions 42 and 2 convex portions 41. Therefore, the corrugated portion 40 is connected to the tread contact surface 3 and the tread sidewall 4 at the positions of the concave portions 42.

[0038] For the corrugated portion 40, the corrugated portion width direction distance W1, which is the distance from the tread end A to the ground contact side end portion 43 in the corrugated portion 40, satisfies the relationship of 0.01W ≦ W1 ≦ 0.15W with respect to the tread width W, which is the width in the tire width direction of the outer peripheral surface of the tread portion 2. In this case, the ground contact side end portion 43 is the connection portion of the corrugated portion 40 with the tread contact surface 3. Also, the tread end A is the intersection of the extension line 3a obtained by extending the profile of the tread contact surface 3 outward in the tire width direction and the extension line 4a obtained by extending the profile of the tread sidewall 4 outward in the tire diameter direction. Further, the tread width W is the distance in the tire width direction between the tread ends A of the shoulder land portions 31 disposed on both sides in the tire width direction.

[0039] The profiles of the tread contact surface 3 and the tread sidewall 4 are the contour lines of the pneumatic tire 1 in the tire meridian section and are measured using a laser profiler. As the laser profiler, for example, a tire profile measuring device (manufactured by Matsuo Co., Ltd.) is used.

[0040] In addition, when the corrugated portion 40 is disposed only on one shoulder land portion 31 in the tire width direction, at the shoulder land portion 31 on the side where the shoulder land portion 31 is not disposed, the intersection of the tread contact surface 3 and the tread sidewall 4 is treated as the tread end A. For this reason, when the corrugated portion 40 is disposed only on one shoulder land portion 31 in the tire width direction, the tread width W is the distance in the tire width direction between the tread end A at the shoulder land portion 31 on the side where the corrugated portion 40 is disposed and the tread end A which is the intersection of the tread contact surface 3 and the tread sidewall 4 at the shoulder land portion 31 on the side where the corrugated portion 40 is not disposed.

[0041] Further, the corrugated portion 40 satisfies the relationship of 0.1L ≦ L1 ≦ 0.6L, where L1 is the distance in the radial direction of the corrugated portion from the tread end A to the sidewall side end portion 44 in the corrugated portion 40, with respect to the distance L from the tread end A to the sector dividing position portion 5. In this case, the sidewall side end portion 44 is the connecting portion of the corrugated portion 40 with the tread sidewall 4.

[0042] In addition, the sector dividing position portion 5 is located at a position corresponding to the boundary portion between a sector mold (not shown) for forming the tread portion 2 and a side mold (not shown) for forming the sidewall portion 8 when the pneumatic tire 1 is molded by a mold (not shown). The sector dividing position portion 5 is formed, for example, by protruding convexly from the tire surface near the boundary between the tread portion 2 and the sidewall portion 8, and the convex portion extending in the tire circumferential direction.

[0043] That is, at the boundary between the sector mold and the side mold used for vulcanizing and molding the pneumatic tire 1 in the pneumatic tire 1, rib-shaped protrusions having a width of about 2 mm to 3 mm and extending in the tire circumferential direction are formed by the residual rubber bitten by the sector mold and the side mold during vulcanization molding. The sector split position portion 5 is such a rib-shaped protrusion formed in this way during vulcanization molding.

[0044] Incidentally, the sector split position portion 5 is located at the position of the so-called design end E, which is the end in the tire width direction of the tread pattern of the tread portion 2. Therefore, the distance L is, in other words, the distance from the tread end A to the design end E, and the corrugated portion 40 satisfies the relationship of 0.1L ≦ L1 ≦ 0.6L, where L1 is the radial distance of the corrugated portion with respect to the distance L from the tread end A to the design end E.

[0045] Also, the side wall side end portion 44 of the corrugated portion 40 is located radially outside the tire with respect to the intersection point P of the extension line 14a extending the radially outer surface of the cross belts 141 and 142 of the belt layer 14 toward the tread side wall 4 and the tread side wall 4.

[0046] The corrugated portion 40 formed in this way has the ground contact side end portion 43 located on the tire ground contact end T or radially outside the tire ground contact end T in the tire width direction. In the present embodiment, the ground contact side end portion 43 of the corrugated portion 40 is located on the tire ground contact end T.

[0047] The tire ground contact end T in this case is the maximum width position 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 a load corresponding to a specified load is applied while being placed perpendicular to the flat plate in a stationary state. The specified load here refers to the "maximum load capacity" specified by JATMA, the maximum value of "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" specified by TRA, or "LOAD CAPACITY" specified by ETRTO.

[0048] A belt layer 14 is disposed on the inner side in the tire radial direction of the tread portion 2. Among a pair of intersecting belts 141 and 142 of the belt layer 14, the width B in the tire width direction of the intersecting belt 142 on the outer side in the tire radial direction is 101% or more with respect to the tire contact width TW (see FIG. 1). The tire contact width TW in this case is the distance in the tire width direction on 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 a load corresponding to a specified load is applied while being placed perpendicular to the flat plate in a stationary state. That is, the tire contact width TW is the distance in the tire width direction between the tire contact ends T located on both sides of the tire equatorial plane CL in the tire width direction.

[0049] FIG. 3 is a detailed view of the wavy portion 40 shown in FIG. 2. The wavy portion 40 having the convex portion 41 and the concave portion 42 is formed such that a virtual chamfering line R that passes through the ground contact side end portion 43 and the side wall side end portion 44, which are both end portions of the wavy portion 40 in the tire meridian cross section, and contacts at least one convex portion 41 is an arc that protrudes outward of the tire. That is, the wavy portion 40 is formed in a shape in which the ground contact side end portion 43, the side wall side end portion 44, and the virtual chamfering line R that contacts at least one convex portion 41 are formed as an arc that protrudes outward of the tire. For this reason, the wavy portion 40 formed in a shape that oscillates in the tire meridian cross section by having the convex portion 41 and the concave portion 42 is formed in a form that protrudes outward of the tire when viewed as a whole of the wavy portion 40.

[0050] Further, in the wavy portion 40, the distance D1 from the tread end A to the virtual chamfering line R satisfies the relationship of 0.3D ≦ D1 ≦ 0.5D with respect to the groove depth D (see FIG. 2) of the circumferential main groove 50. The circumferential main groove 50 in this case is the outermost circumferential main groove 51 (see FIG. 2) that partitions the shoulder land portion 31. The distance D1 from the tread end A to the virtual chamfering line R is the shortest distance from the tread end A to the virtual chamfering line R in the tire meridian cross section.

[0051] Further, in the corrugated portion 40, the distance D2 from the virtual chamfering line R to the bottom of the recess 42 satisfies the relationship of 0.5D1 ≤ D2 with respect to the distance D1 from the tread edge A to the virtual chamfering line R. In this case, the bottom of the recess 42 corresponds to, for example, the portion corresponding to the groove bottom of the groove when the recess 42 is regarded as a groove. Therefore, when the recess 42 is regarded as a groove, the distance D2 is a value corresponding to the groove depth from the virtual chamfering line R. In the corrugated portion 40, the distance D2 in all the recesses 42 of the corrugated portion 40 satisfies the relationship of 0.5D1 ≤ D2 with respect to the distance D1 from the tread edge A to the virtual chamfering line R.

[0052] Furthermore, in the corrugated portion 40, the respective distances D2 from the virtual chamfering line R to the bottoms of the plurality of recesses 42 are 50% or more with respect to the distance D2 of the recess 42 having the largest distance D2 from the virtual chamfering line R to the bottom of the recess 42 among the plurality of recesses 42. In other words, among the plurality of recesses 42 of the corrugated portion 40, the distance D2 of the recess 42 having the smallest distance D2 from the virtual chamfering line R to the bottom of the recess 42 is 50% or more with respect to the distance D2 of the recess 42 having the largest distance D2 from the virtual chamfering line R to the bottom of the recess 42.

[0053] Note that the distance D2 of the recess 42 having the smallest distance D2 from the virtual chamfering line R to the bottom of the recess 42 is preferably 80% or more with respect to the distance D2 of the recess 42 having the largest distance D2 from the virtual chamfering line R to the bottom of the recess 42. In the present embodiment, in the plurality of recesses 42 of the corrugated portion 40, the distances D2 from the virtual chamfering line R to the bottoms of the recesses 42 are substantially the same as each other.

[0054] Figure 4 is a view taken along line G-G of Figure 2. In the tread portion 2, in addition to the circumferential main grooves 50 extending in the tire circumferential direction, a plurality of lug grooves 55 extending in the tire width direction are arranged. A plurality of the lug grooves 55 are also arranged side by side in the tire circumferential direction at the position where the shoulder land portion 31 in the tire width direction is located. For this reason, the shoulder land portion 31 is formed as a so-called block-shaped land portion 30 in which both side portions in the tire circumferential direction are partitioned by the lug grooves 55. That is, the shoulder land portion 31 is formed as a block-shaped shoulder block.

[0055] The corrugated portions 40 are arranged on each of the block-shaped shoulder land portions 31. The corrugated portions 40 arranged on each shoulder land portion 31 are arranged at the same positions in the tire width direction and the tire diameter direction, the number of convex portions 41 and concave portions 42 is the same, and the shape in the tire meridian cross section is substantially the same. For this reason, the corrugated portions 40 arranged on each shoulder land portion 31 are formed in a form straddling between the shoulder land portions 31. Thereby, the corrugated portions 40 provided on the shoulder land portion 31 are continuously formed in the tire circumferential direction with respect to the shoulder land portion 31. That is, the plurality of corrugated portions 40 provided on the plurality of shoulder land portions 31 are continuously formed linearly in the tire circumferential direction.

[0056] Since the pneumatic tire 1 according to the present embodiment is a radial tire for a light truck, it is mainly mounted on a small truck and used. When mounting the pneumatic tire 1 on a vehicle, the pneumatic tire 1 is rim-mounted on a rim wheel and mounted on the vehicle in a state where air is filled and inflated inside.

[0057] When a vehicle equipped with a pneumatic tire 1 travels, the pneumatic tire 1 rotates while the portion of the tread contact surface 3 of the tread portion 2 that is located below comes into contact with the road surface. When the vehicle equipped with the pneumatic tire 1 travels on a dry road surface, it mainly travels by transmitting driving force, braking force, or generating turning force to the road surface through the frictional force between the tread contact surface 3 and the road surface. Also, when traveling on a wet road surface, the water between the tread contact surface 3 and the road surface enters the grooves such as the circumferential main grooves 50 and the lug grooves 55, and the vehicle travels while draining the water between the tread contact surface 3 and the road surface with these grooves. As a result, the tread contact surface 3 easily comes into contact with the road surface, and the vehicle can travel due to the frictional force between the tread contact surface 3 and the road surface.

[0058] In addition, the vehicle may travel on an unpaved road, so-called off-road, or on a snow-covered road surface. In the shoulder land portion 31, a corrugated portion 40 formed across the tread contact surface 3 and the tread sidewall 4 is arranged. Therefore, it is possible to improve the mud performance, which is the running performance when traveling on a road surface having mud with fluidity such as a muddy road, and the snow performance, which is the running performance when traveling on a snow-covered road surface.

[0059] That is, examples of the performance required for mud performance and snow performance include turning performance on a muddy road or a snow-covered road surface. When the vehicle turns on a muddy road or a snow-covered road surface, the load acting on the pneumatic tire 1 moves to the outside in the radial direction of the turn compared to when traveling straight, so that the portion of the pneumatic tire 1 closer to the outside in the radial direction of the turn easily comes into contact with the road surface. Therefore, when the vehicle turns, the pneumatic tire 1 easily comes into contact with the vicinity of the end portion in the tire width direction of the tread portion 2.

[0060] In this embodiment, since the wavy portion 40 is formed across the tread contact surface 3 and the tread sidewall 4 on the shoulder land portion 31 disposed on the outer side in the tire width direction, when the portion closer to the outer side in the radial direction of turning becomes likely to contact the road surface during turning of the vehicle, the wavy portion 40 formed on the shoulder land portion 31 becomes likely to contact the road surface. That is, during turning of the vehicle, since the load acting on the pneumatic tire 1 moves to the outer side in the radial direction of turning rather than during straight running, the pneumatic tire 1 is elastically deformed by this load, and the wavy portion 40 located near the end portion in the tire width direction in the tread portion 2 becomes likely to contact the road surface.

[0061] Since the convex portions 41 and the concave portions 42 of the wavy portion 40 are alternately arranged, when the vehicle turns on a muddy road or a snow-covered road surface and the wavy portion 40 contacts the road surface, the mud on the muddy road or the snow on the snow-covered road surface enters the concave portions 42 of the wavy portion 40. When the mud on the muddy road or the snow on the snow-covered road surface enters the concave portions 42 of the wavy portion 40, the resistance between the mud on the muddy road or the snow on the snow-covered road surface and the wavy portion 40 increases due to the shear stress of these mud and snow. These resistances during turning of the vehicle become the resistance in the tire width direction between the muddy road or the snow-covered road surface and the pneumatic tire 1 with respect to the pneumatic tire 1, and act as a cornering force on the turning vehicle. Therefore, the turning performance during running on a muddy road or a snow-covered road surface can be ensured, and the mud performance and the snow performance can be improved.

[0062] On the other hand, the ground contact surface side end portion 43, which is the connection portion of the wavy portion 40 with the tread contact surface 3, is located on the tire ground contact end T or on the outer side in the tire width direction from the tire ground contact end T. That is, the entire wavy portion 40 is located on the outer side in the tire width direction from the tire ground contact end T. For this reason, during straight running of the vehicle, the wavy portion 40 does not locate within the tire ground contact width TW, and the ground contact area during straight running of the vehicle can be ensured. Therefore, the handling stability during straight running can be ensured by the appropriately ensured ground contact area.

[0063] Therefore, by providing the corrugated portion 40 on the shoulder land portion 31, the turning performance when driving on muddy roads or snow-covered road surfaces can be improved by the corrugated portion 40 without impairing the handling stability during straight running. As a result, the mud performance and snow performance can be improved while maintaining the handling stability during straight running.

[0064] Further, the corrugated portion 40 is formed in a shape where the virtual chamfering line R is an arc convex to the outside of the tire. Thereby, it is possible to easily bring the corrugated portion 40 into contact with the ground when the vehicle turns, and the turning performance when driving on muddy roads or snow-covered road surfaces can be more reliably improved by the corrugated portion 40. As a result, the mud performance and snow performance can be more reliably improved.

[0065] Also, since the distance D1 from the tread edge A to the virtual chamfering line R of the corrugated portion 40 satisfies the relationship of 0.3D ≤ D1 ≤ 0.5D with respect to the groove depth D of the circumferential main groove 50, the corrugated portion 40 is not brought into contact with the ground during straight running, and the turning performance when driving on muddy roads or snow-covered road surfaces can be improved by the corrugated portion 40. That is, when the distance D1 from the tread edge A to the virtual chamfering line R is less than 0.3D with respect to the groove depth D of the circumferential main groove 50, the distance D1 from the tread edge A to the virtual chamfering line R is too small, so there is a risk that the corrugated portion 40 is likely to come into contact with the ground during straight running. In this case, depending on the driving conditions during straight running, the corrugated portion 40 may or may not come into contact with the ground, and due to the change in the contact area depending on the presence or absence of contact of the corrugated portion 40, it may be difficult to ensure the handling stability during straight running. Further, when the distance D1 from the tread edge A to the virtual chamfering line R is greater than 0.5D with respect to the groove depth D of the circumferential main groove 50, the distance D1 from the tread edge A to the virtual chamfering line R is too large, so there is a risk that the corrugated portion 40 is difficult to come into contact with the ground during turning. In this case, there is a risk that the corrugated portion 40 is difficult to come into contact with the ground even during turning on muddy roads or snow-covered road surfaces, and it may be difficult to improve the turning performance when driving on muddy roads or snow-covered road surfaces by the corrugated portion 40.

[0066] On the other hand, when the distance D1 from the tread edge A to the virtual chamfering line R is in the range of 0.3D ≤ D1 ≤ 0.5D with respect to the groove depth D of the circumferential main groove 50, the wavy portion 40 can be brought into contact with the ground during turning travel without bringing the wavy portion 40 into contact with the ground during straight running, and the turning performance during travel on muddy roads or snow-covered road surfaces can be improved by the wavy portion 40. As a result, it is possible to more reliably improve the mud performance and snow performance while maintaining the handling stability during straight running.

[0067] Further, in the wavy portion 40, since the distance D2 from the virtual chamfering line R to the bottom of the concave portion 42 satisfies the relationship of 0.5D1 ≤ D2 with respect to the distance D1 from the tread edge A to the virtual chamfering line R, the turning performance during travel on muddy roads or snow-covered road surfaces can be more reliably improved by the wavy portion 40. That is, when the distance D2 from the virtual chamfering line R to the bottom of the concave portion 42 of the wavy portion 40 is such that 0.5D1 > D2 with respect to the distance D1 from the tread edge A to the virtual chamfering line R, there is a risk that the distance D2 from the virtual chamfering line R to the bottom of the concave portion 42 of the wavy portion 40 is too small. In this case, since the concave portion 42 of the wavy portion 40 is too shallow, there is a risk that it becomes difficult to improve the turning performance on muddy roads or snow-covered road surfaces even when the wavy portion 40 comes into contact with the ground during turning performance on muddy roads or snow-covered road surfaces.

[0068] On the other hand, when the distance D2 from the virtual chamfering line R to the bottom of the concave portion 42 of the wavy portion 40 satisfies the relationship of 0.5D1 ≤ D2 with respect to the distance D1 from the tread edge A to the virtual chamfering line R, when the wavy portion 40 comes into contact with the ground during turning performance on muddy roads or snow-covered road surfaces, the turning performance on muddy roads or snow-covered road surfaces can be more reliably improved by the wavy portion 40. As a result, the mud performance and snow performance can be more reliably improved.

[0069] Further, in the corrugated portion 40, since the distance D2 from the virtual chamfering line R to the bottom of each of the plurality of recesses 42 is 50% or more of the distance D2 of the recess 42 having the largest distance D2 from the virtual chamfering line R to the bottom among the plurality of recesses 42, the rigidity of the shoulder land portion 31 for each position of the recess 42 can be made as uniform as possible. As a result, it is possible to suppress the occurrence of failures of the shoulder land portion 31, such as chipping of the shoulder land portion 31, which is caused by a large rigidity difference within the range where the corrugated portion 40 is arranged in the shoulder land portion 31. Therefore, the turning performance on muddy roads and snow-covered road surfaces can be continuously improved by the corrugated portion 40. As a result, the mud performance and snow performance can be continuously improved.

[0070] Further, in the corrugated portion 40, since the corrugated portion width direction distance W1, which is the distance from the tread edge A to the ground contact side end portion 43, satisfies the relationship of 0.01W ≦ W1 ≦ 0.15W with respect to the tread width W, it is possible to improve the turning performance during traveling on a muddy road or a snow-covered road surface by the corrugated portion 40 without grounding the corrugated portion 40 during straight-ahead traveling. That is, when the corrugated portion width direction distance W1 of the corrugated portion 40 is less than 0.01 with respect to the tread width W, since the corrugated portion width direction distance W1 is too small, even if the corrugated portion 40 contacts the ground during turning on a muddy road or a snow-covered road surface, it may be difficult to ensure the ground contact width of the corrugated portion 40. In this case, there is a possibility that it may be difficult to improve the turning performance on a muddy road or a snow-covered road surface by the corrugated portion 40. Further, when the corrugated portion width direction distance W1 of the corrugated portion 40 is greater than 0.15W with respect to the tread width W, since the corrugated portion width direction distance W1 is too large, there is a possibility that the corrugated portion 40 may easily contact the ground during straight-ahead traveling of the vehicle. In this case, depending on the traveling conditions during straight-ahead traveling, the corrugated portion 40 may or may not contact the ground, and there is a possibility that it may be difficult to ensure the handling stability during straight-ahead traveling due to the change in the ground contact area depending on the presence or absence of the ground contact of the corrugated portion 40.

[0071] On the other hand, when the wave width direction distance W1 of the corrugated portion 40 satisfies the relationship of 0.01W ≤ W1 ≤ 0.15W with respect to the tread width W, the corrugated portion 40 can be prevented from contacting the ground during straight running, and the contact width of the corrugated portion 40 during turning can be ensured to be an appropriate size. As a result, the turning performance during driving on muddy roads or snowy road surfaces can be improved by the corrugated portion 40. Consequently, it is possible to more reliably improve the mud performance and snow performance while maintaining the handling stability during straight running.

[0072] Further, for the corrugated portion 40, since the wave radial direction distance L1, which is the distance from the tread end A to the side wall side end portion 44, satisfies the relationship of 0.1L ≤ L1 ≤ 0.6L with respect to the distance L from the tread end A to the sector dividing position portion 5, it is possible to ensure the rubber thickness at the position of the recessed portion 42 to suppress the occurrence of failures and improve the turning performance during driving on muddy roads or snowy road surfaces by the corrugated portion 40. That is, when the wave radial direction distance L1 of the corrugated portion 40 is L1 < 0.1L with respect to the distance L from the tread end A to the sector dividing position portion 5, since the wave radial direction distance L1 is too small, even if the corrugated portion 40 contacts the ground during turning on a muddy road or a snowy road surface, it may be difficult to ensure the contact width of the corrugated portion 40. In this case, there is a possibility that it becomes difficult to improve the turning performance on a muddy road or a snowy road surface by the corrugated portion 40. Also, when the wave radial direction distance L1 of the corrugated portion 40 is L1 > 0.6L with respect to the distance L from the tread end A to the sector dividing position portion 5, since the wave radial direction distance L1 is too large, there is a possibility that the corrugated portion 40 approaches too closely to the members arranged inside the pneumatic tire 1 such as the belt layer 14. In this case, there is a possibility that it becomes difficult to ensure the rubber thickness at the position of the recessed portion 42 of the corrugated portion 40, and there is a possibility that failures such as cracks are likely to occur due to an increase in stress at the position of the recessed portion 42 where the rubber thickness is thin.

[0073] On the other hand, when the wavy portion radial distance L1 of the wavy portion 40 satisfies the relationship of 0.1L ≤ L1 ≤ 0.6L with respect to the distance L from the tread end A to the sector division position portion 5, it is possible to secure the rubber thickness at the position of the concave portion 42 to suppress the occurrence of failures, and to secure an appropriate ground contact width of the wavy portion 40 during turning travel. The turning performance during travel on a muddy road or a snow-covered road surface can be improved by the wavy portion 40. Therefore, the turning performance on a muddy road or a snow-covered road surface can be continuously improved by the wavy portion 40. As a result, the mud performance and the snow performance can be continuously improved.

[0074] Further, since the wavy portion 40 is formed continuously in the tire circumferential direction with respect to the shoulder land portion 31, the wavy portion 40 can be continuously grounded when the vehicle turns. Thereby, the turning performance during travel on a muddy road or a snow-covered road surface can be continuously improved by the wavy portion 40 regardless of the position in the tire circumferential direction of the pneumatic tire 1. As a result, the mud performance and the snow performance can be more reliably improved.

[0075] Further, in the belt layer 14, since the width B in the tire width direction of the cross belt 142 on the outer side in the tire radial direction among the pair of cross belts 141 and 142 is 101% or more with respect to the tire contact width TW, it is possible to ensure the rigidity near both ends in the tire width direction of the tread portion 2, and it is possible to make it difficult for the wavy portion 40 to contact the ground during straight running. That is, when the width B in the tire width direction of the cross belt 142 on the outer side in the tire radial direction among the pair of cross belts 141 and 142 is less than 101% with respect to the tire contact width TW, there is a risk that it becomes difficult to ensure the rigidity near both ends in the tire width direction of the tread portion 2. In this case, when the tread contact surface 3 comes into contact with the ground, the elastic deformation near both ends in the tire width direction of the tread portion 2 becomes large due to the load acting on the pneumatic tire 1, and there is a risk that the wavy portion 40 provided on the shoulder land portion 31 becomes likely to contact the ground even during straight running. For this reason, there is a possibility that the wavy portion 40 contacts or does not contact the ground depending on the load acting on the pneumatic tire 1 during straight running, and due to the change in the contact area according to the presence or absence of the contact of the wavy portion 40, there is a risk that it becomes difficult to ensure the handling stability during straight running.

[0076] On the other hand, when the width B in the tire width direction of the cross belt 142 on the outer side in the tire radial direction is 101% or more with respect to the tire contact width TW, the rigidity near both ends in the tire width direction of the tread portion 2 can be more reliably ensured by the cross belts 141 and 142. Thereby, the elastic deformation near both ends in the tire width direction of the tread portion 2 when the tread contact surface 3 comes into contact with the ground can be suppressed, and it is possible to suppress the wavy portion 40 provided on the shoulder land portion 31 from contacting the ground during straight running. As a result, it is possible to improve the mud performance and the snow performance while more reliably maintaining the handling stability during straight running.

[0077] In addition, since the number of recessed portions 42 of the corrugated portion 40 is within the range of 2 or more and 6 or less, and the number of protruding portions 41 is within the range of 1 or more and 5 or less, the occurrence of failures in the corrugated portion 40 can be suppressed, and the turning performance when driving on muddy roads or snow-covered road surfaces can be more reliably improved. That is, when the number of recessed portions 42 of the corrugated portion 40 is 7 or more and the number of protruding portions 41 is 5 or more, there is a risk that the wavelength of the corrugated portion 40, that is, the interval between the recessed portions 42 and the interval between the protruding portions 41 becomes too small. In this case, there is a risk that it becomes difficult to ensure the rigidity of the corrugated portion 40, and since it becomes difficult to increase the resistance between the mud on the muddy road or the snow on the snow-covered road surface and the corrugated portion 40 by the corrugated portion 40, there is a risk that it becomes difficult to ensure the turning performance when driving on muddy roads or snow-covered road surfaces. Further, when it is difficult to ensure the rigidity of the corrugated portion 40 because the wavelength of the corrugated portion 40 is too small, there is a risk that failures such as wear of the corrugated portion 40 are likely to occur due to the low rigidity of the corrugated portion 40.

[0078] On the other hand, when the number of recessed portions 42 of the corrugated portion 40 is within the range of 2 or more and 6 or less, and the number of protruding portions 41 is within the range of 1 or more and 5 or less, it is possible to suppress the wavelength of the corrugated portion 40 from becoming too small, so that the rigidity of the corrugated portion 40 having the recessed portions 42 and the protruding portions 41 can be ensured. As a result, the resistance between the mud on the muddy road or the snow on the snow-covered road surface and the corrugated portion 40 can be more reliably increased by the corrugated portion 40 with ensured rigidity, and the turning performance when driving on muddy roads or snow-covered road surfaces can be more reliably improved. Further, by ensuring the rigidity of the corrugated portion 40, the occurrence of failures such as wear of the corrugated portion 40 can be suppressed, and the turning performance on muddy roads or snow-covered road surfaces can be continuously improved by the corrugated portion 40. As a result, the mud performance and snow performance can be more reliably improved.

[0079] In addition, since the concave portion 42 and the convex portion 41 of the corrugated portion 40 are each formed in an arc shape in the tire meridian cross-section, mud and snow that have entered the concave portion 42 during driving on a muddy road or a snow-covered road surface can be smoothly discharged from the concave portion 42. As a result, it is possible to suppress the situation where the resistance between the mud on the muddy road or the snow on the snow-covered road surface and the corrugated portion 40 cannot be increased due to clogging of the concave portion 42 with mud or snow, and the turning performance during driving on a muddy road or a snow-covered road surface can be more reliably improved by the corrugated portion 40. Further, when the concave portion 42 and the convex portion 41 of the corrugated portion 40 are formed with corners in the tire meridian cross-section, there is a possibility that external vehicle noise and abnormal noise may occur when the corrugated portion 40 comes into contact with the ground. However, since the concave portion 42 and the convex portion 41 are formed in an arc shape, the generation of external vehicle noise and abnormal noise when the corrugated portion 40 comes into contact with the ground can be suppressed. As a result, it is possible to more reliably improve the mud performance and the snow performance while suppressing the generation of noise during vehicle driving.

[0080] [Modification Example] In the above-described embodiment, the corrugated portion 40 disposed on the shoulder land portion 31 is formed continuously in a straight line in the tire circumferential direction. However, the corrugated portion 40 does not necessarily have to be formed in a straight line in the tire circumferential direction. FIG. 5 is a plan view of a main part of the tread portion 2 in a modification example of the pneumatic tire 1 according to the embodiment, in which the corrugated portion 40 is formed continuously in the tire circumferential direction while being curved. The corrugated portion 40 disposed on the shoulder land portion 31 may be formed continuously in the tire circumferential direction while repeatedly curving in the tire width direction, for example, as shown in FIG. 5. That is, the plurality of corrugated portions 40 respectively provided on the plurality of shoulder land portions 31 may be formed continuously in the tire circumferential direction while oscillating in the tire width direction.

[0081] Even if the wavy portion 40 is not linearly continuous in the tire circumferential direction, by being continuously formed in the tire circumferential direction, the wavy portion 40 can be continuously brought into contact with the ground when the vehicle turns. Further, since the wavy portion 40 is continuously formed in the tire circumferential direction while repeatedly curving in the tire width direction, while ensuring the rigidity of the shoulder land portion 31, it is possible to make it easier for the wavy portion 40 to come into contact with the ground under a wider variety of turning conditions when the vehicle turns. Thereby, while ensuring the handling stability during straight running, the turning performance during running on muddy roads or snow-covered road surfaces can be improved by the wavy portion 40. As a result, it is possible to improve the mud performance and snow performance while maintaining the handling stability during straight running.

[0082] Also, in the above-described embodiment, the concave portion 42 and the convex portion 41 of the wavy portion 40 are each formed in an arc shape in the tire meridian cross-section, but the concave portion 42 and the convex portion 41 may be formed in a shape other than an arc shape. The concave portion 42 and the convex portion 41 of the wavy portion 40 may be formed, for example, in a zigzag shape by bending in the tire meridian cross-section, or may be formed in a rectangular wave shape in the tire meridian cross-section. Regardless of the shape of the concave portion 42 and the convex portion 41, the wavy portion 40 is formed across the tread contact surface 3 and the tread sidewall 4 with respect to the shoulder land portion 31 while having an amplitude in the tire meridian cross-section, thereby ensuring the turning performance during running on muddy roads or snow-covered road surfaces. Thereby, while maintaining the handling stability during straight running, it is possible to improve the mud performance and snow performance.

[0083] Also, the above-described embodiments and modified examples may be combined as appropriate. Further, in the above-described embodiment, the pneumatic tire 1 has been described as an example of the tire according to the present invention, but the tire according to the present invention may be other than the 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 a gas.

[0084] [Examples] Figs. 6A and 6B are charts showing the results of the performance evaluation test of the pneumatic tire. Hereinafter, for the above pneumatic tire 1, a performance evaluation test conducted on a conventional pneumatic tire, the pneumatic tire 1 according to the present invention, and a pneumatic tire of a comparative example compared with the pneumatic tire 1 according to the present invention will be described. The performance evaluation test was conducted on the handling stability during straight running, and the mud performance and snow performance.

[0085] The performance evaluation test was carried out by mounting a pneumatic tire 1 with a tire size of 265 / 70R17 115S defined by JATMA on a JATMA standard rim wheel with a rim size of 17×8J, mounting the test tire on an evaluation vehicle of a pickup truck type, adjusting the air pressure to 230 kPa for both the front and rear wheels, and running the evaluation vehicle.

[0086] The evaluation method for each test item is as follows: for the handling stability during straight running, when the evaluation vehicle equipped with the test tire runs on the test course, the handling stability during straight running is compared by the sensory evaluation of the test driver, and the sensory evaluation of the test driver is evaluated by expressing it as an index with a conventional example described later being 100. The larger this value is, the better the handling stability during straight running is shown. In addition, for the handling stability during straight running, if the index is 98 or more, it is considered that the same level as the conventional example is maintained, and the handling stability during straight running is ensured without inferiority compared with the conventional example.

[0087] Regarding the mud performance, a vehicle equipped with test tires was driven on a muddy road test course, and the driving performance when turning on the muddy road was compared by the sensory evaluation of the test driver. Also, regarding the snow performance, a vehicle equipped with test tires was driven on a snow-covered road test course, and the driving performance when turning on the snow-covered road was compared by the sensory evaluation of the test driver. The mud performance and the snow performance were evaluated by combining the sensory evaluations when turning on these muddy roads and the sensory evaluations when turning on the snow-covered road, and expressing the combined sensory evaluation as an index with a conventional example described later set to 100. The larger this numerical value is, the higher the turning performance on both the muddy road and the snow-covered road, indicating excellent mud performance and snow performance.

[0088] The performance evaluation test was conducted on 14 types of pneumatic tires, including a conventional pneumatic tire as an example of a conventional pneumatic tire, Examples 1 to 12 of the pneumatic tire 1 according to the present invention, and a comparative example which is a pneumatic tire for comparing with the pneumatic tire 1 according to the present invention. Among these, in the conventional example, the wavy portion 40 is not arranged on the shoulder land portion 31, and the portion extending across the tread ground contact surface 3 and the tread sidewall 4 on the shoulder land portion 31 is formed in an arcuate chamfered shape in the tire meridian cross-section. Also, in the comparative example, although the wavy portion 40 is arranged on the shoulder land portion 31, the ground contact surface side end portion 43 of the wavy portion 40 is located inside the tire width direction from the tire ground contact end T, and the wavy portion 40 is in a form of contacting the ground during straight running.

[0089] In contrast, in Examples 1 to 12 which are examples of the pneumatic tire 1 according to the present invention, the corrugated portion 40 is disposed on all of the shoulder land portions 31, and the ground contact side end portion 43 of the corrugated portion 40 is located on the tire ground contact end T. Further, in the pneumatic tire 1 according to Examples 1 to 12, the direction in which the arc of the virtual chamfering line R is convex, the ratio of the distance D1 from the tread end A to the virtual chamfering line R to the groove depth D of the circumferential main groove 50, the ratio of the distance D2 from the virtual chamfering line R to the bottom of the concave portion 42 of the corrugated portion 40 to the distance D1 from the tread end A to the virtual chamfering line R, the ratio of the distance D2 of the concave portion 42 having the largest distance D2 from the virtual chamfering line R to the bottom of the concave portion 42 to the distance D2 of the concave portion 42 having the smallest distance D2 from the virtual chamfering line R to the bottom of the concave portion 42, the ratio of the corrugated portion width direction distance W1 to the tread width W, the ratio of the corrugated portion radial direction distance L1 to the distance L from the tread end A to the sector cut position portion 5, the ratio of the width B in the tire width direction of the cross belt 142 on the radially outer side of the tire to the tire ground contact width TW, and the shapes of the convex portion 41 and the concave portion 42 of the corrugated portion 40 are different from each other.

[0090] As a result of performing a performance evaluation test using these pneumatic tires 1, as shown in FIGS. 6A and 6B, the pneumatic tires 1 according to Examples 1 to 12 can improve the mud performance and snow performance while suppressing as much as possible the deterioration of the handling stability during straight running compared with the conventional example, and can also improve the mud performance and snow performance while suppressing as much as possible the deterioration of the handling stability during straight running compared with the comparative example. That is, the pneumatic tires 1 according to Examples 1 to 12 can improve the mud performance and snow performance while maintaining the handling stability during straight running.

[0091] The present disclosure includes the following inventions. Invention [1] In the tread portion, a plurality of circumferential main grooves extending in the tire circumferential direction; a plurality of land portions partitioned by the plurality of circumferential main grooves; and Among the plurality of land portions, on the shoulder land portion which is the land portion located most outward in the tire width direction, on at least one of the shoulder land portions located on both sides in the tire width direction, a wavy portion formed across the tread contact surface and the tread sidewall which is the end surface of the tread portion in the tire width direction is arranged. The wavy portion is formed across the tread contact surface and the tread sidewall while oscillating by alternately arranging convex portions that protrude to the outside of the tire and concave portions that protrude to the inner cavity side of the tire in the tire meridian cross section. A tire, characterized in that a ground contact side end portion, which is a connection portion of the wavy portion with the tread contact surface, is located on the tire ground contact end or outside the tire ground contact end in the tire width direction. Invention [2] The tire according to Invention [1], wherein in the tire meridian cross section, a virtual chamfering line passing through a sidewall side end portion, which is a connection portion of the wavy portion and the tread sidewall, and the ground contact side end portion and contacting at least one of the convex portions is formed as an arc that protrudes to the outside of the tire. Invention [3] The tire according to Invention [2], wherein a distance D1 from a tread end, which is an intersection of an extension line obtained by extending the profile of the tread contact surface to the outside in the tire width direction and an extension line obtained by extending the profile of the tread sidewall to the outside in the tire radial direction, to the virtual chamfering line satisfies a relationship of 0.3D ≦ D1 ≦ 0.5D with respect to a groove depth D of the circumferential main groove. Invention [4] The tire according to Invention [3], wherein a distance D2 from the virtual chamfering line to the bottom of the concave portion of the wavy portion satisfies a relationship of 0.5D1 ≦ D2 with respect to the distance D1 from the tread end to the virtual chamfering line. Invention [5] The tire according to any one of Inventions [2] to [4], wherein for each of the distances D2 from the virtual chamfering line to the bottom of the concave portions of the plurality of concave portions, the distance D2 is 50% or more with respect to the distance D2 of the concave portion having the largest distance D2 from the virtual chamfering line to the bottom of the concave portions among the plurality of concave portions. Invention [6] The wavy portion is the distance from the tread end, which is the intersection of the extension line obtained by extending the profile of the tread ground contact surface outward in the tire width direction and the extension line obtained by extending the profile of the tread sidewall outward in the tire radial direction, to the ground contact surface side end portion. The wavy portion width direction distance W1 satisfies the relationship of 0.01W ≤ W1 ≤ 0.15W with respect to the tread width W, which is the width in the tire width direction of the outer peripheral surface of the tread portion. The tire according to any one of Inventions [1] to [5]. Invention [7] The wavy portion is the distance from the tread end, which is the intersection of the extension line obtained by extending the profile of the tread ground contact surface outward in the tire width direction and the extension line obtained by extending the profile of the tread sidewall outward in the tire radial direction, to the sidewall side end portion, which is the connection portion between the wavy portion and the tread sidewall in the tire meridian cross section. The wavy portion radial direction distance L1 satisfies the relationship of 0.1L ≤ L1 ≤ 0.6L with respect to the distance L from the tread end to the sector cut position portion. The tire according to any one of Inventions [1] to [6]. Invention [8] The wavy portion is formed continuously in the tire circumferential direction with respect to the shoulder land portion. The tire according to any one of Inventions [1] to [7]. Invention [9] A pair of intersecting belts are arranged inside the tread portion in the tire radial direction, The width in the tire width direction of the intersecting belt on the outer side in the tire radial direction among the pair of intersecting belts is 101% or more with respect to the tire ground contact width. The tire according to any one of Inventions [1] to [8]. Invention

[10] The number of the concave portions of the wavy portion is within a range of 2 or more and 6 or less, and the number of the convex portions is within a range of 1 or more and 5 or less. The tire according to any one of Inventions [1] to [9]. Invention

[11] The concave portions and the convex portions of the wavy portion are each formed in an arc shape in the tire meridian cross section. The tire according to any one of Inventions [1] to

[10] .

Explanation of Signs

[0092] 1 Pneumatic tire 2 Tread portion 3 Tread contact surface 3a Extension line 4 Tread sidewall 4a Extension line 5 Sector dividing position portion 6 Tread rubber 7 Shoulder portion 8 Sidewall portion 10 Bead portion 11 Bead core 12 Bead filler 13 Carcass layer 14 Belt layer 141, 142 Cross belt 143, 144 Belt cover 16 Inner liner 17 Rim cushion rubber 18 Tire inner surface 30 Land portion 31 Shoulder land portion 40 Wavy portion 41 Convex portion 42 Concave portion 43 Contact surface side end 44 Sidewall side end 50 Circumferential main groove 51 Outermost circumferential direction main groove 55 Lug groove

Claims

1. In the tread portion, a plurality of circumferential main grooves extending in the tire circumferential direction, and a plurality of land portions partitioned by the plurality of circumferential main grooves, are provided, among the plurality of land portions, on the shoulder land portion which is the outermost land portion in the tire width direction, on at least one of the shoulder land portions located on both sides in the tire width direction, a wavy portion formed across the tread contact surface and the tread side wall which is the end surface of the tread portion in the tire width direction is arranged, the wavy portion is formed across the tread contact surface and the tread side wall while oscillating by alternately arranging convex portions that protrude to the tire outer side and concave portions that protrude to the tire inner cavity side in the tire meridian cross section, a tire, characterized in that a ground contact side end portion which is a connection portion of the wavy portion with the tread contact surface is located on the tire ground contact end or on the outer side in the tire width direction from the tire ground contact end.

2. The tire according to claim 1, wherein in the tire meridian cross section, a virtual chamfering line passing through a side wall side end portion which is a connection portion of the wavy portion and the tread side wall and the ground contact side end portion and contacting at least one of the convex portions is formed as an arc that protrudes to the tire outer side.

3. The distance D from the tread edge, which is the intersection of an extension line obtained by extending the profile of the tread ground contact surface outward in the tire width direction and an extension line obtained by extending the profile of the tread sidewall outward in the tire diameter direction, to the virtual chamfering line １ satisfies the relation of 0.3D ≤ D １ ≤ 0.5D, and the tire according to claim 2

4. The wavy portion is the distance D from the virtual chamfering line to the bottom of the recess ２ is the distance D from the tread edge to the virtual chamfering line １ is 0.5D with respect to １ ≦ D ２ The tire according to claim 3, which satisfies the relationship of

5. The undulated portion is the distance D from the virtual chamfer line to the bottom of each of the plurality of the recesses ２ among the plurality of the recesses, is the distance D from the virtual chamfer line to the bottom of the recess ２ and is the distance D of the recess having the largest distance D ２ The tire according to claim 2 or 3, wherein the distance D is 50% or more with respect to the distance D of the recess having the largest distance D among the plurality of the recesses.

6. The wavy portion is a wavy portion width direction distance W which is the distance from the tread end, which is the intersection of an extension line obtained by extending the profile of the tread ground contact surface outward in the tire width direction and an extension line obtained by extending the profile of the tread sidewall outward in the tire diameter direction, to the ground contact surface side end portion. １ is such that, with respect to the tread width W which is the width in the tire width direction of the outer peripheral surface of the tread portion, 0.01W ≤ W １ ≤ 0.15W, and the tire according to claim 1 or 2 satisfying this relationship.

7. The wavy portion is a wavy portion radial distance L, which is the distance from the tread end, which is the intersection of an extension line obtained by extending the profile of the tread ground contact surface outward in the tire width direction and an extension line obtained by extending the profile of the tread sidewall outward in the tire radial direction, to the sidewall side end portion, which is the connection portion between the wavy portion and the tread sidewall in the tire meridian cross section. １ satisfies the relationship of 0.1L ≦ L with respect to the distance L from the tread end to the sector division position portion １ ≦ 0.6L. The tire according to claim 1 or 2.

8. The tire according to claim 1 or 2, wherein the wavy portion is formed continuously in the tire circumferential direction with respect to the shoulder land portion.

9. A pair of intersecting belts are arranged inside the tread portion in the tire radial direction, the tire according to claim 1 or 2, wherein the width in the tire width direction of the intersecting belt on the outer side in the tire radial direction among the pair of intersecting belts is 101% or more with respect to the tire ground contact width.

10. The tire according to claim 1 or 2, wherein the number of the concave portions of the wavy portion is in the range of 2 or more and 6 or less, and the number of the convex portions is in the range of 1 or more and 5 or less.

11. The tire according to claim 1 or 2, wherein the concave portions and the convex portions of the wavy portion are each formed in an arc shape in the tire meridian cross section.

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