Tire

Abstract

To provide a tire capable of further improving bad road running performance while securing excellent block durability.SOLUTION: In a tire, a plurality of shoulder blocks 12 is provided in a shoulder area of a tread part 1, a plurality of side blocks 13 is provided in adjacent side areas outside in a tire width direction of the shoulder area, one side block 13 is arranged at a position outside in the tire width direction of a block group composed of two or more shoulder blocks 12 adjacent to each other in a tire circumferential direction, a bent recess 20 composed of a first recess 21 and a second recess 22 that extend along the tire circumferential direction and a third recess 23 that connects these recesses to be inclined and extend relative to the tire circumferential direction is provided on a side face of each of the shoulder blocks 12, and a bent projection composed of a first projection 31 and a second projection 32 that extend along the tire circumferential direction and a third projection 33 that connects these projections to be inclined and extend relative to the tire circumferential direction is provided on a surface of each of the side blocks 13.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a tire intended for running on unpaved roads and the like, and more particularly to a tire which enables further improvement in rough road running performance while ensuring excellent block durability. [Background technology]

[0002] Tires (e.g., all-terrain tires, all-terrain type tires, etc.) that are intended to run on unpaved roads (uneven ground, muddy ground, sandy ground, rocky ground, etc.) in addition to paved road surfaces are required to have excellent running performance on various road surfaces, and in particular, are required to have excellent off-road performance (bad road running performance). In such tires, not only the tread portion that contacts the road surface on paved roads, but also the side area (area located between the tread portion and the sidewall portion) that may contact mud, snow, sand, stones, rocks, etc. on the road surface on unpaved roads (hereinafter, these are collectively referred to as "mud, etc.") is provided with unevenness (side blocks, etc.), thereby biting into the mud, etc., and obtaining traction performance (see, for example, Patent Documents 1 and 2). In recent years, the performance required for tires has become more sophisticated, and further improvement in bad road running performance is required. In addition, since the side blocks tend to be easily damaged by stones, rocks, foreign objects, etc. on the road surface on unpaved roads (bad roads), it is also required to ensure durability. For this reason, there is a demand to improve off-road performance while ensuring durability (particularly block durability) and achieving a high level of both performance characteristics. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-124733 A [Patent Document 2] JP 2020-044882 A Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a tire which enables further improvement in rough road running performance while ensuring excellent block durability. [Means for solving the problem]

[0005] In order to achieve the above object, the tire of the present invention has a tread portion extending in a circumferential direction of the tire and forming an annular shape, and a pair of sidewall portions disposed on both sides of the tread portion, the tire having a surface of the tread portion having a pair of main grooves extending along the tire circumferential direction on both sides of the tire equator, a shoulder region located on the outer side of the main grooves in the tire width direction is provided with a plurality of shoulder lug grooves extending from the main grooves toward the outer side in the tire width direction and spaced apart in the tire circumferential direction, and a plurality of shoulder blocks partitioned by the main grooves and the shoulder lug grooves and arranged along the tire circumferential direction, a plurality of side blocks protruding from an outer surface of the sidewall portion are provided in a side region adjacent to the outer side in the tire width direction of the shoulder region, and the shoulder lug grooves are provided between the side blocks adjacent in the tire circumferential direction. The tire has a side groove that connects the two shoulder blocks and extends along the tire radial direction, and one of the side blocks is arranged at a position on the tire widthwise outer side of a block group consisting of two or more shoulder blocks adjacent in the tire circumferential direction, and each side of the shoulder block has a bent recess that is recessed further than other parts of the side surface, and each of the bent recesses consists of a first recess and a second recess that extend along the tire circumferential direction, and a third recess that connects the first recess and the second recess and extends at an angle with respect to the tire circumferential direction, and each of the side blocks has a bent convex portion that is raised higher than other parts of the surface, and each of the bent convex portions consists of a first convex portion and a second convex portion that extend along the tire circumferential direction, and a third convex portion that connects the first convex portion and the second convex portion and extends at an angle with respect to the tire circumferential direction. Effect of the Invention

[0006] In the tire of the present invention, when a plurality of side blocks are provided in the side region, one side block is disposed at the outer position in the tire width direction of a block group consisting of two or more shoulder blocks adjacent in the tire circumferential direction, so that the whole consisting of the block group and the side blocks functions substantially as a large block, thereby improving the block durability. In addition, since a bent recess consisting of the first to third recesses is provided in each shoulder block, and a bent convex portion consisting of the first to third convex portions is provided in each side block, the uneven shape of the region extending from the side surface of the shoulder block to the surface of the side block becomes complex, so that mud, etc. can be efficiently bitten on unpaved roads, improving traction performance, and excellent rough road running performance can be exhibited. In particular, since the bent recess and the bent convex portion each include a portion extending along the tire circumferential direction (first recess and second recess, first convex portion and second convex portion) and a portion extending at an angle to the tire circumferential direction (third recess, third convex portion), edge effects can be exhibited in various directions, and traction performance can be efficiently improved. These cooperations can achieve a high degree of both block durability and rough road running performance.

[0007] In the present invention, it is preferable that the first recess opens into a shoulder lug groove adjacent to one side of the shoulder block in the tire circumferential direction, and the second recess opens into a shoulder lug groove adjacent to the other side of the shoulder block in the tire circumferential direction, so that both ends of the flex recess communicate with the shoulder lug groove, making it easier to discharge mud and the like in the flex recess, and thus improving traction performance can be expected.

[0008] In the present invention, it is preferable that the first convex portion is connected to the side groove adjacent to one side of the side block in the tire circumferential direction, and the second convex portion is connected to the side groove adjacent to the other side of the side block in the tire circumferential direction, so that the bent convex portion extends across the entire width of the side block (the entire area from one end to the other end in the tire circumferential direction), thereby increasing the rigidity of the side block and being advantageous for improving traction performance.

[0009] In the present invention, the length of one of the first convex portion and the second convex portion in the tire circumferential direction may be greater than the length of the other of the first convex portion and the second convex portion in the tire circumferential direction. By making the lengths of the first convex portion and the second convex portion different in this way, the unevenness of the bent convex portion becomes complex, which is advantageous for improving traction performance.

[0010] In the present invention, the depth of the bent recess with respect to the side surface of the shoulder block is preferably 0.5 mm to 2.0 mm, which is advantageous for achieving both block durability and rough road performance.

[0011] In the present invention, the height of the bent convex portion relative to the surface of the side block is preferably 0.5 mm to 15 mm, which is advantageous for achieving both block durability and rough road performance.

[0012] In the present invention, the angle that the third recessed portion forms with respect to the tire circumferential direction is preferably 20° to 50°. Also, the angle that the third protruding portion forms with respect to the tire circumferential direction is preferably 30° to 60°. By setting the angles of each portion in this manner, the shape of the bent recessed portion and the bent protruding portion becomes good, which is advantageous for improving the traction performance and the rough road running performance. The "angle that the third recessed portion forms with respect to the tire circumferential direction" is measured based on a virtual line passing through the center of the third recessed portion in the width direction. Similarly, the "angle that the third protruding portion forms with respect to the tire circumferential direction" is measured based on a virtual line passing through the center of the third protruding portion in the width direction.

[0013] In the present invention, it is preferable that the third recess and the third protrusion are inclined in the same direction with respect to the tire circumferential direction, and the difference in the inclination angle with respect to the tire circumferential direction is 15° or less. When the third recess and the third protrusion are inclined in the same direction in this manner, the bent recess and the bent protrusion have similar shapes, and the combination of these recesses and protrusions improves the recess and protrusion shape in the region from the side surface of the shoulder block to the surface of the side block, which is advantageous for improving traction performance and improving rough road driving performance.

[0014] In the present invention, it is preferable that the second convex portion is located at the innermost position in the tire radial direction of the side block, the first convex portion is located at the outer side in the tire radial direction of the second convex portion, and the surface of the side block is recessed more than the bent convex portion at a position surrounded by the first convex portion and the third convex portion. This makes the unevenness of the side block complex, which is advantageous for improving traction performance and rough road running performance.

[0015] The tire of the present invention is preferably a pneumatic tire, but may also be a non-pneumatic tire. In the case of a pneumatic tire, the inside of the tire can be filled with air, an inert gas such as nitrogen, or other gases. [Brief description of the drawings]

[0016] [Figure 1] 1 is a meridian cross-sectional view of a tire according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a perspective view showing a shoulder region and a side region of a tire according to an embodiment of the present invention. [Diagram 3] FIG. 2 is an explanatory diagram showing a schematic view of a shoulder block (side surface) and a side block (front surface) of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The configuration of the present invention will be described in detail below with reference to the accompanying drawings.

[0018] When the tire of the present invention is a pneumatic tire as shown in Fig. 1, it includes a tread portion 1 that contacts the road surface, a pair of sidewall portions 2 arranged on both sides of the tread portion 1, and a pair of bead portions 3 arranged on the tire radial inner side of the sidewall portions 2. In Fig. 1, the symbol CL indicates the tire equator. Although not depicted in Fig. 1 because it is a meridian cross section, the tread portion 1, the sidewall portions 2, and the bead portions 3 each extend in the tire circumferential direction to form an annular shape, thereby forming a basic toroidal structure of a pneumatic tire. The following explanation using Fig. 1 is basically based on the meridian cross section shown in the figure, but each tire component extends in the tire circumferential direction to form an annular shape.

[0019] A carcass layer 4 is installed between a pair of left and right bead portions 3. The carcass layer 4 includes a plurality of reinforcing cords extending in the tire radial direction, and is folded back from the vehicle inner side to the vehicle outer side around the bead cores 5 arranged in each bead portion 3. A bead filler 6 is arranged on the outer periphery of the bead cores 5, and the bead filler 6 is wrapped by the main body and the folded back portion of the carcass layer 4. Meanwhile, a plurality of belt layers 7 (two layers in FIG. 1) are embedded on the outer periphery side of the carcass layer 4 in the tread portion 1. Each belt layer 7 includes a plurality of reinforcing cords inclined with respect to the tire circumferential direction, and the reinforcing cords are arranged so as to cross each other between the layers. In these belt layers 7, the inclination angle of the reinforcing cords with respect to the tire circumferential direction is set to, for example, a range of 10° to 40°. Furthermore, at least one belt reinforcing layer 8 (two layers in FIG. 1) is provided on the outer periphery side of the belt layer 7. The belt reinforcing layer 8 includes organic fiber cords oriented in the tire circumferential direction. In the belt reinforcing layer 8, the organic fiber cords are set at an angle of, for example, 0° to 5° with respect to the tire circumferential direction.

[0020] Since the present invention relates to the shoulder and side regions of a tire as described below, the basic structure (cross-sectional structure) of the tire is not limited to the general structure described above. In addition, the detailed shapes (tread pattern) of the grooves and blocks formed on the surface of the tread portion 1 are not particularly limited except for the shoulder region described below. The tread pattern of the portion excluding the shoulder region described below is preferably a pattern mainly composed of blocks suitable for unpaved roads. The present invention can be applied to various tires, including non-pneumatic tires, as long as they have an area (parts corresponding to the shoulder and side regions) that may come into contact with mud on the road surface when traveling on an unpaved road.

[0021] As shown in Figs. 1 and 2, a pair of main grooves 10 are formed on the surface of the tread portion 1, extending along the tire circumferential direction on both sides of the tire equator CL. The main grooves 10 may have a zigzag shape in which linear portions inclined in one direction with respect to the tire circumferential direction and linear portions inclined in the other direction are alternately connected in the tire circumferential direction. The region between the pair of main grooves 10 is a center region (a region in which the structure is not particularly limited in the present invention and any tread pattern can be adopted), and the regions on the outer sides of each main groove 10 in the tire width direction are shoulder regions. The main grooves 10 preferably have a groove width of 3 mm to 13 mm, more preferably 5 mm to 11 mm, and a groove depth of 8 mm to 16 mm, more preferably 10 mm to 15 mm.

[0022] A land portion (shoulder land portion) defined on the outer side of the main groove 10 in the tire width direction is provided with a shoulder lug groove 11 extending from the main groove 10 toward the outer side in the tire width direction. A plurality of shoulder lug grooves 11 may be provided at intervals in the tire circumferential direction. The shoulder lug grooves 11 define the shoulder land portion into a plurality of blocks (shoulder blocks 12). When the main groove 10 has a zigzag shape, the shoulder lug groove 11 may be connected to a bending point on the outer side of each main groove 10 in the tire width direction. The groove width of the shoulder lug groove 11 is not particularly limited, but is preferably 70% to 98%, more preferably 80% to 95% of the groove width of the main groove 10. The groove depth of the shoulder lug groove 11 is not particularly limited, but is preferably 75% to 100%, more preferably 80% to 98% of the groove depth of the main groove 10.

[0023] When the region adjacent to the shoulder region on the outer side in the tire width direction is defined as a side region, a plurality of side blocks 13 protruding from the outer surface of the sidewall portion 2 are provided in this side region. The protruding height of each side block 13 from the sidewall surface is not particularly limited, but can be set to, for example, 1 mm to 10 mm. As shown in Figs. 2 and 3, each side block 13 is disposed at a position on the outer side in the tire width direction of a block group consisting of two or more shoulder blocks 12 adjacent in the tire circumferential direction. For example, in the illustrated example, one side block 13 is disposed at a position on the outer side in the tire width direction of a block group consisting of two shoulder blocks 12. In other words, a side groove 14 extending along the tire width direction (tire radial direction) is formed between the side blocks 13 adjacent in the tire circumferential direction, and this side groove 14 is connected to at least every other shoulder lug groove 11 arranged at intervals in the tire circumferential direction. Between the shoulder lug grooves 11 and side grooves 14 connected in this manner, one side block 13 and two or more shoulder blocks 12 (and one or more shoulder lug grooves 11 that are not connected to the side groove 14) are arranged.

[0024] The side blocks 13 are preferably arranged in an appropriate range in the tire radial direction so that they can appropriately contact the road surface when the tire is buried in mud or the like while traveling on an unpaved road. Specifically, the innermost end of the side block 13 in the tire radial direction is preferably present in a range of 20% to 50% of the tire cross-sectional height SH from the tire equator CL position toward the tire radially inward. In other words, the distance D from the tire equator CL position to the innermost end of the side block 13 in the tire radial direction is preferably 20% to 50% of the tire cross-sectional height SH. By arranging the side blocks 13 in an appropriate range in the tire radial direction of the sidewall portion 2 in this way, it is possible to effectively improve the running performance on unpaved roads. In addition, since the size of the side blocks 13 can be appropriately secured, it is advantageous to secure block rigidity and improve durability. If the distance D is less than 20% of the tire cross-sectional height SH, the side blocks 13 become small, making it difficult to maintain good block durability. If the distance D exceeds 50% of the tire cross-sectional height SH, the side blocks 13 become too large, which may affect normal running performance. In relation to the arrangement of the side blocks 13, the boundary between the shoulder region and the side region should be located within a range of 20% to 25% of the tire cross-sectional height SH from the tire equator CL toward the tire radially inward, regardless of the presence or absence of the protrusions 17.

[0025] In the above-mentioned combination of two or more shoulder blocks 12 and one side block 13, a bent recess 20 is provided on each side surface of the shoulder block 12 (the surface of the shoulder block 12 when the tire is viewed from the side) that is recessed from other parts of the side surface of the shoulder block 12. Each bent recess 20 is composed of a first recess 21 and a second recess 22 extending along the tire circumferential direction, and a third recess 23 connecting the first recess 21 and the second recess 22 and extending at an angle with respect to the tire circumferential direction. Similarly, a bent protruding portion 30 is provided on each surface of the side block 13 (the surface of the side block 13 when the tire is viewed from the side) that is raised from other parts of the surface of the side block 13. Each bent protruding portion 30 is composed of a first protruding portion 31 and a second protruding portion 32 extending along the tire circumferential direction, and a third protruding portion 33 connecting the first protruding portion 31 and the second protruding portion 32 and extending at an angle with respect to the tire circumferential direction.

[0026] In the tire of the present invention, the shoulder block 12 (block group) and the side block 13 as a whole function as a large block, and the rigidity of the large block can be secured, so that the block durability can be improved. On the other hand, each shoulder block 12 is provided with a bent recess 20 consisting of a first recess 21, a second recess 22, and a third recess 23, and each side block 13 is provided with a bent convex portion 30 consisting of a first convex portion 31, a second convex portion 32, and a third convex portion 33, so that the uneven shape of the area extending from the side surface of the shoulder block 12 to the surface of the side block 13 becomes complex, and thus mud and the like can be efficiently bitten on unpaved roads, improving traction performance and providing excellent rough road running performance. In particular, the bent recess 20 and the bent convex portion 30 each include a portion extending along the tire circumferential direction (the first recess 21 and the second recess 22, the first convex portion 31 and the second convex portion 32) and a portion extending at an angle to the tire circumferential direction (the third recess 23, the third convex portion 33), so that an edge effect can be provided in various directions, and the traction performance can be efficiently improved. This collaboration makes it possible to achieve a high level of both block durability and off-road performance.

[0027] In the illustrated example, a protrusion 15 is present at the boundary between the outer side surface of the shoulder block 12 in the tire width direction and the surface of the side block 13 (the boundary between the shoulder region and the side region), protruding from the sidewall surface and extending around the entire circumference of the tire. This protrusion 15 is an element formed due to the split position of the mold, and is not necessarily provided. This protrusion 15 is an element that does not need to be taken into consideration in the present invention, but since it is an element formed during manufacturing, the shoulder region and side region may be divided based on the protrusion 15. In other words, the shoulder region can be regarded as the region adjacent to the protrusion 15 on the inner side in the tire width direction, and the side region can be regarded as the region adjacent to the protrusion 15 on the inner side in the tire radial direction.

[0028] As described above, the bent recess 20 is a portion recessed from the side surface of the shoulder block 12, and the bent protruding portion 30 is a portion raised from the surface of the side block 13. Therefore, the bent protruding portion 30 does not need to protrude from the side surface of the shoulder block 12. For example, in the illustrated example, the height relationship is such that the side surface of the shoulder block 12 and the upper surface of the bent protruding portion 30 are connected with the protrusion 15 in between, but even with this shape, the bent recess 20 is recessed from the side surface of the shoulder block 12, and the bent protruding portion 30 is raised from the surface of the side block 13, so that the uneven shape intended by the present invention is satisfied.

[0029] The relationship in numbers of side blocks 13 and shoulder blocks 12 in a combination of two or more shoulder blocks 12 adjacent in the tire width direction and one side block 13 is preferably two shoulder blocks 12 for one side block 13. This provides a good balance in the numbers of each block in the combination of side blocks 13 and shoulder blocks 12, which is advantageous for achieving both block durability and rough road performance.

[0030] The depth of the flex recess 20 relative to the side surface of the shoulder block 12 is preferably 0.5 mm to 2.0 mm, more preferably 0.5 mm to 1.5 mm. This is advantageous for achieving both block durability and rough road running performance. If the depth of the flex recess 20 relative to the side surface of the shoulder block 12 is less than 0.5 mm, the flex recess 20 is not recessed sufficiently, and sufficient unevenness is not formed by the flex recess 20, so that the effect of improving traction performance cannot be expected sufficiently. If the depth of the flex recess 20 relative to the side surface of the shoulder block 12 exceeds 2.0 mm, the flex recess 20 is too deep, so the rigidity of the shoulder block 12 decreases, making it difficult to maintain sufficient block durability.

[0031] The height of the bent convex portion 30 relative to the surface of the side block is preferably 0.5 mm to 15 mm, more preferably 1 mm to 3 mm. This is advantageous for achieving both block durability and rough road running performance. If the height of the bent convex portion 30 relative to the surface of the side block 13 is less than 0.5 mm, the bent convex portion 30 does not rise sufficiently, and the bent convex portion 30 does not form sufficient unevenness, so that the effect of improving traction performance cannot be expected sufficiently. If the height of the bent convex portion 30 relative to the surface of the side block 13 exceeds 15 mm, the bent convex portion 30 protrudes extremely from the surroundings, so that the bent convex portion 30 itself becomes easily damaged, and it becomes difficult to maintain block durability.

[0032] The bent recess 20 is not particularly limited in its specific shape as long as it has a bent shape consisting of the three parts (first recess 21, second recess 22, and third recess 23) described above. However, as in the illustrated example, it is preferable that the first recess 21 is located radially outward of the second recess 22. In particular, in the illustrated example, the first recess 21 arranged on one side in the tire circumferential direction (the right side in the figure) is located radially outward of the second recess 22 arranged on the other side in the tire circumferential direction (the left side in the figure). Furthermore, in the illustrated example, the second recess 22 is located on the innermost side in the tire radial direction of the side surface of the shoulder block 12 and extends so as to contact the protrusion 17 described above. In the present invention, it is preferable that the bent recess 20 having the above-mentioned shape is provided in each of two or more shoulder blocks 12 adjacent to each other in the tire circumferential direction, and the bent recess 20 of each shoulder block 12 has a similar shape. By providing the bent recess 20 in this way, the unevenness having a direction based on the bent recess 20 is repeatedly arranged in the tire circumferential direction, which is advantageous for effectively biting mud and the like and improving the rough road running performance.

[0033] The bent convex portion 30 is also not particularly limited in its specific shape as long as it has a bent shape consisting of the above-mentioned three parts (first convex portion 31, second convex portion 32, and third convex portion 33), but as in the illustrated example, it is preferable that the first convex portion 31 is located further outward in the tire radial direction than the second convex portion 32. In particular, as in the illustrated example, it is preferable that the first convex portion 31 arranged on one side in the tire circumferential direction (the right side in the figure) is located further outward in the tire radial direction than the second convex portion 32 arranged on the other side in the tire circumferential direction (the left side in the figure). In other words, it is preferable that the bent convex portion 30 has a bent shape similar to that of the bent concave portion 20, except that the concaves and convexes are reversed and the length in the tire circumferential direction is changed.

[0034] By satisfying the above-mentioned arrangement of the first recessed portion 21 and the second recessed portion 22 and the arrangement of the first convex portion 31 and the second convex portion 32, the third recessed portion 23 and the third convex portion 33 are inclined in the same direction with respect to the tire circumferential direction while satisfying, and the difference in the inclination angle with respect to the tire circumferential direction (the difference between the angles α and β described below) is preferably 15° or less, more preferably 10° or less. As a result, the bent convex portion 30 and the bent recessed portion 20 have a more similar bent shape, so that the bent recessed portion 20 and the bent recessed portion 30 formed in the shoulder block 12 and the side block 13 become uneven with directionality as a whole, which is advantageous for effectively biting in mud and the like and improving rough road driving performance.

[0035] When the third recessed portion 23 and the third protruding portion 33 are inclined in the same direction with respect to the tire circumferential direction as described above, the angle α of the third recessed portion 23 with respect to the tire circumferential direction is preferably 20° to 50°, more preferably 30° to 40°. The angle β of the third protruding portion 33 with respect to the tire circumferential direction is preferably 30° to 60°, more preferably 40° to 50°. By setting the angles of each portion in this manner, the shape of the bent recessed portion 20 and the bent protruding portion 30 becomes good, which is advantageous for improving the traction performance and improving the rough road running performance. If the angle α is less than 20°, the bent recessed portion 20 does not bend sufficiently, and the effect of improving the traction performance is limited. If the angle α exceeds 50°, there is a risk that the cut resistance will decrease. If the angle β is less than 30°, the bent protruding portion 30 does not bend sufficiently, and the effect of improving the traction performance is limited. If the angle β exceeds 60°, there is a risk that the cut resistance will decrease.

[0036] It is preferable that the first recess 21 opens into the shoulder lug groove 11 adjacent to one side of the shoulder block 12 in the tire circumferential direction, and the second recess 22 opens into the shoulder lug groove 11 adjacent to the other side of the shoulder block 12 in the tire circumferential direction. This makes it easier for mud and the like in the bending recess 20 to be discharged because both ends of the bending recess 20 communicate with the shoulder lug groove 11, which is expected to improve traction performance.

[0037] It is preferable that the first convex portion 31 is connected to the adjacent side groove 14 on one side of the side block 13 in the tire circumferential direction, and the second convex portion 32 is connected to the adjacent side groove 14 on the other side of the side block 13 in the tire circumferential direction. This allows the bent convex portion 30 to extend across the entire width of the side block 13 (the entire area from one end to the other end in the tire circumferential direction), thereby increasing the rigidity of the side block 13 and being advantageous for improving traction performance.

[0038] The first convex portion 31 and the second convex portion 32 may have the same circumferential length, but one of them may be longer than the other. In the illustrated example, the second convex portion 32 arranged on the outer side in the tire radial direction has a longer circumferential length than the first convex portion 31 arranged on the inner side in the tire radial direction. More specifically, in the illustrated example, the first convex portion 31 and the third convex portion 33 are provided in a range corresponding to one shoulder block 12, and the second convex portion 32 is provided in a range corresponding to one shoulder block 12 and shoulder lug groove 11, so that the circumferential lengths of the first convex portion 31 and the second convex portion 32 have a greater-than-less relationship (first convex portion < second convex portion). By forming the bent convex portion 30 in this manner, the unevenness of the bent convex portion 30 becomes complex, which is advantageous for improving traction performance.

[0039] In the illustrated example, the second convex portion 32 is disposed radially inward of the first convex portion 31, and is disposed at the radially innermost position of the side block 13. Meanwhile, a surface of the side block 13 (reference numeral 13a in the drawing) that is recessed from the bent convex portion 30 is present at a position surrounded by the first convex portion 31 and the third convex portion 33. In other words, it is preferable that a surface of the side block 13 (a surface recessed from the bent convex portion 30) is present on both the inner and outer sides of the bent convex portion 30 in the radial direction of the tire. This makes the unevenness of the side block 13 more complex, which is advantageous for improving traction performance and improving rough road driving performance.

[0040] As the present invention is primarily concerned with the bending recess 20 and the bending protrusion 30, other structures are not particularly limited, but as in the illustrated example, a side recess 34 recessed into the surface of the side block 13 may be provided on an extension line of the shoulder lug groove 11 located between a block group consisting of two shoulder blocks 12. This side recess 34 terminates within the side block 13 so as to be interrupted by the bending protrusion 30. Providing such a side recess 34 further complicates the unevenness of the side block 13, which is advantageous for improving traction performance and improving rough road driving performance.

[0041] The present invention will be further described below with reference to examples, but the scope of the present invention is not limited to these examples. EXAMPLES

[0042] Eighteen types of pneumatic tires (Conventional Example 1, Comparative Examples 1-3, and Examples 1-14) were produced, with a tire size of LT265 / 70R17 121 / 118S, a basic structure (cross-sectional structure) as illustrated in FIG. 1, and structures of the shoulder region and side region based on FIG. 2, and the number of shoulder blocks adjacent to the radially outer side of one side block, the presence or absence of a bent recess, the angle α of the third recess with respect to the tire circumferential direction of the tire, the end shape of the first recess, the end shape of the second recess, the presence or absence of a bent convex portion, the angle β of the third convex portion with respect to the tire circumferential direction of the tire, the end shape of the first convex portion, the end shape of the second convex portion, the angle difference |β|-|α| between the angle α of the third recess with respect to the tire circumferential direction and the angle β of the third convex portion with respect to the tire circumferential direction, the depth of the bent recess, the depth of the bent convex portion, and the presence or absence of a side block surface on the radially inner side of the bent convex portion, as shown in Tables 1-2.

[0043] The tread pattern in the center region was common to all examples, with a structure in which a row of blocks was arranged between a pair of main grooves and on each side of the tire equator.

[0044] In the column of "angle α of third recess with respect to tire circumferential direction" in Table 1, when the number of shoulder blocks adjacent to one side block on the tire radial outside is "2" and a bent recess is provided in each shoulder block, each bent recess includes a third recess, so the value of each angle α is presented. Note that the negative value of one angle α in Example 13 means that the inclination direction is opposite to that of the other angle α. Similarly, the example (Example 14) in which the angle β of the third convex portion with respect to the tire circumferential direction is negative means that the inclination direction of the third concave portion and the inclination direction of the third convex portion are opposite to each other.

[0045] The columns "End Shape of First Recess" and "End Shape of Second Recess" in Tables 1 and 2 indicate whether one end of the first recess or the second recess communicates with the shoulder lug groove, with "opening" indicating that it opens into the shoulder lug groove and "terminating" indicating that it terminates within the shoulder block. The columns "End Shape of First Convex" and "End Shape of Second Convex" in Tables 1 and 2 indicate whether one end of the first convex or the second convex connects to a side groove, with "connection" indicating that it connects to the side groove and "termination" indicating that it terminates within the side block.

[0046] The pneumatic tires were evaluated for rough road performance and block durability by the following evaluation methods, and the results are shown in Table 1.

[0047] Rough road performance Each test tire was mounted on a wheel with a rim size of 17x8J, and the front tire was set at an air pressure of 450kPa and the rear tire at an air pressure of 550kPa. The test tire was then mounted on a test vehicle (traction test vehicle), and a sensory evaluation of traction performance (starting performance) was carried out by a test driver on a test road consisting of an unpaved road (gravel surface). The evaluation results were expressed as an index with the value of Conventional Example 1 being 100. The higher the index value, the better the snow performance.

[0048] Block durability (cut resistance) Each test tire was mounted on a wheel with a rim size of 17×8J, and the air pressure was set to 350 kPa and mounted on a test vehicle (four-wheel drive SUV). After driving 1000 km on an off-road endurance road, the total length of the cuts on the side was measured. The evaluation results were expressed as an index with the reciprocal of the measurement value of Comparative Example 1 set to 100. The larger the index value, the smaller the total length of the cuts and the better the block durability (cut resistance).

[0049] [Table 1]

[0050] [Table 2]

[0051] As is clear from Table 1, the pneumatic tires of Examples 1 to 14 have improved rough road running performance and block durability compared to Conventional Example 1, and these performances are well balanced. In Comparative Example 1, two shoulder blocks are adjacent to one side block, and therefore, although the block durability was improved compared to Conventional Example 1, the effect of improving the rough road running performance was not obtained because neither a bent recess nor a bent protruding portion is provided. In Comparative Example 2, the effect of sufficiently improving the rough road running performance was not obtained because a bent recess is provided but a bent protruding portion is not provided. In Comparative Example 3, the effect of sufficiently improving the rough road running performance was not obtained because a bent protruding portion is provided but a bent recess is not provided.

[0052] The present disclosure includes the following inventions. Invention [1] A tire having a tread portion extending in a circumferential direction of the tire and forming an annular shape, and a pair of sidewall portions disposed on both sides of the tread portion, A pair of main grooves extending along a tire circumferential direction on both sides of a tire equator are provided on a surface of the tread portion, A shoulder region located on the outer side of the main groove in the tire width direction is provided with a plurality of shoulder lug grooves extending from the main groove toward the outer side in the tire width direction and spaced apart in the tire circumferential direction, and a plurality of shoulder blocks partitioned by the main groove and the shoulder lug groove and arranged along the tire circumferential direction, A plurality of side blocks protruding from an outer surface of the sidewall portion are provided in a side region adjacent to an outer side of the shoulder region in the tire width direction, and a side groove connected to the shoulder lug groove and extending along the tire radial direction is provided between the side blocks adjacent in the tire circumferential direction, One side block is disposed at an outer position in the tire width direction of a block group consisting of two or more shoulder blocks adjacent in the tire circumferential direction, a bending recess portion is provided on each side surface of the shoulder block so as to be recessed relative to other portions of the side surface, and each bending recess portion includes a first recess portion and a second recess portion extending along the tire circumferential direction, and a third recess portion connecting the first recess portion and the second recess portion and extending at an angle relative to the tire circumferential direction, a bent convex portion is provided on the surface of each of the side blocks, the bent convex portion being higher than other portions of the surface, and each of the bent convex portions comprises a first convex portion and a second convex portion extending along the tire circumferential direction, and a third convex portion connecting the first convex portion and the second convex portion and extending at an angle with respect to the tire circumferential direction. Invention [2] A tire as described in invention [1], characterized in that the first recess opens into a shoulder lug groove adjacent to one side of the shoulder block in the tire circumferential direction, and the second recess opens into a shoulder lug groove adjacent to the other side of the shoulder block in the tire circumferential direction. Invention [3] A tire as described in invention [1] or [2], characterized in that the first convex portion is connected to a side groove adjacent to one side of the side block in the tire circumferential direction, and the second convex portion is connected to a side groove adjacent to the other side of the side block in the tire circumferential direction. Invention [4] The tire according to any one of inventions [1] to [3], wherein the circumferential length of one of the first convex portion and the second convex portion is greater than the circumferential length of the other of the first convex portion and the second convex portion. Invention [5] The tire according to any one of inventions [1] to [4], characterized in that the depth of the bending recess with respect to the side surface of the shoulder block is 0.5 mm to 2.0 mm. Invention [6] The tire according to any one of inventions [1] to [5], characterized in that the height of the bent convex portion with respect to the surface of the side block is 0.5 mm to 15 mm. Invention [7] The tire according to any one of inventions [1] to [6], wherein the third recessed portion forms an angle of 20° to 50° with respect to the tire circumferential direction. Invention [8] The tire according to any one of inventions [1] to [7], wherein the third convex portion forms an angle of 30° to 60° with respect to the tire circumferential direction. Invention [9] A tire according to any one of inventions [1] to [8], characterized in that the third recess and the third protrusion are inclined in the same direction with respect to the tire circumferential direction, and the difference in their inclination angles with respect to the tire circumferential direction is 15° or less. Invention

[10] A tire according to any one of inventions [1] to [9], characterized in that the second convex portion is located at the innermost position in the tire radial direction of the side block, the first convex portion is located at the outer side in the tire radial direction than the second convex portion, and the surface of the side block is recessed more than the bent convex portion at a position surrounded by the first convex portion and the third convex portion. [Explanation of symbols]

[0053] 1 Tread section 2 Sidewall 3 Bead section 4 Carcass layer 5 Bead Core 6 Bead Filler 7 Belt layer 8 Belt reinforcement layer 10 Main groove 11 Shoulder lug groove 12 Shoulder Block 13 Side Block 14 Side groove 15 protrusion 20 Bend recess 21 First recess 22 Second recess 23 Third recess 30 Bend convex part 31 First convex part 32 Second convex part 33 Third convex part 34 Side recess CL Tire Equator

Claims

1. A tire having a tread portion extending in a circumferential direction of the tire to form an annular shape, and a pair of sidewall portions disposed on both sides of the tread portion, A pair of main grooves extending along a tire circumferential direction on both sides of a tire equator are provided on a surface of the tread portion, A shoulder region located on the outer side of the main groove in the tire width direction is provided with a plurality of shoulder lug grooves extending from the main groove toward the outer side in the tire width direction and spaced apart in the tire circumferential direction, and a plurality of shoulder blocks partitioned by the main groove and the shoulder lug groove and arranged along the tire circumferential direction, A plurality of side blocks protruding from an outer surface of the sidewall portion are provided in a side region adjacent to an outer side of the shoulder region in the tire width direction, and a side groove connected to the shoulder lug groove and extending along the tire radial direction is provided between the side blocks adjacent in the tire circumferential direction, One side block is disposed at an outer side in the tire width direction of a block group consisting of two or more shoulder blocks adjacent in the tire circumferential direction, a bending recess portion is provided on each side surface of the shoulder block so as to be recessed relative to other portions of the side surface, and each bending recess portion includes a first recess portion and a second recess portion extending along the tire circumferential direction, and a third recess portion connecting the first recess portion and the second recess portion and extending at an angle relative to the tire circumferential direction, a bent convex portion is provided on the surface of each of the side blocks, the bent convex portion being higher than other portions of the surface, and each of the bent convex portions comprises a first convex portion and a second convex portion extending along the tire circumferential direction, and a third convex portion connecting the first convex portion and the second convex portion and extending at an angle with respect to the tire circumferential direction.

2. 2. The tire according to claim 1, wherein the first recess opens into a shoulder lug groove adjacent to one side of the shoulder block in the tire circumferential direction, and the second recess opens into a shoulder lug groove adjacent to the other side of the shoulder block in the tire circumferential direction.

3. The tire according to claim 1 or 2, characterized in that the first convex portion is connected to a side groove adjacent to one side of the side block in the tire circumferential direction, and the second convex portion is connected to a side groove adjacent to the other side of the side block in the tire circumferential direction.

4. The tire according to claim 1 or 2, wherein a circumferential length of one of the first convex portion and the second convex portion is greater than a circumferential length of the other of the first convex portion and the second convex portion.

5. 3. The tire according to claim 1, wherein the depth of the bending recess with respect to the side surface of the shoulder block is 0.5 mm to 2.0 mm.

6. 3. The tire according to claim 1, wherein a height of the bent convex portion with respect to a surface of the side block is 0.5 mm to 15 mm.

7. The tire according to claim 1 or 2, characterized in that an angle formed by the third recess with respect to the tire circumferential direction is 20° to 50°.

8. The tire according to claim 1 or 2, characterized in that an angle formed by the third convex portion with respect to the tire circumferential direction is 30° to 60°.

9. 3. The tire according to claim 1, wherein the third recess and the third protrusion are inclined in the same direction with respect to the tire circumferential direction, and a difference in inclination angle between the third recess and the third protrusion with respect to the tire circumferential direction is 15° or less.

10. 3. The tire according to claim 1, wherein the second convex portion is located at the innermost position in the tire radial direction of the side block, the first convex portion is located at the outer side in the tire radial direction of the second convex portion, and the surface of the side block is recessed more than the bent convex portion at a position surrounded by the first convex portion and the third convex portion.

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