Tire

Abstract

To provide a tire that can further improve performance in running on a bad road while securing excellent durability of blocks.SOLUTION: A plurality of shoulder blocks 12 are provided on a shoulder region of a tread part 1; a plurality of side blocks 13 are provided on a side region adjacent to outside in a tire width direction of the shoulder region; two or more shoulder blocks 12 arranged adjacently in a tire circumferential direction and one side block 13 arranged outsides in the tire width direction of the shoulder blocks are grouped into a block group B; and bent side grooves 20 terminating in the side block 13 are formed on an extension line of a shoulder lug groove 11 arranged between the pair of shoulder blocks 12 included in the block group B, where the bent side grooves 20 include a connection part 21 extending from a position of an end part of the shoulder lug groove 11 toward inside in a tire radial direction and a folded-back part 22 bending from an end part inside in the tire radial direction of the connection part 21 to one side in the tire circumferential direction and extending toward outside in the tire radial direction.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] The tire of the present invention for achieving the above object includes 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, 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, and a plurality of shoulder 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. a pair of shoulder blocks each having a widthwise outer circumferential edge and a widthwise outer circumferential edge of the shoulder block, the ... Effect of the Invention

[0006] In providing a plurality of side blocks in the side region of the tire of the present invention, one side block is disposed at the tire width direction outer position 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 block functions substantially as a large block, thereby improving the block durability. Meanwhile, since the bent side groove having the above-mentioned structure is provided in the side block, the traction performance can be improved by its edge effect. In particular, the bent side groove includes a connection portion extending from the end position of the shoulder lug groove toward the tire radial direction inner side, and a folded-back portion bending from the tire radial direction inner end of the connection portion to one side in the tire circumferential direction and extending toward the tire radial direction outer side (i.e., extending in the opposite direction to the connection portion), so that the bent shape exerts an edge effect in various directions, and the traction performance can be effectively improved. In addition, since this bent side groove terminates in the side block, the decrease in block rigidity caused by providing a groove in the block can be suppressed. 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 a first recess is formed adjacent to the other circumferential side of the connection portion, the first recess being higher than the surface of the side block than the bent side groove, and a second recess is formed adjacent to the radially outer side of the turn-up portion, the second recess being higher than the surface of the side block than the bent side groove. By providing the first and second recesses in this way, the unevenness of the surface of the side block can be made more complex while maintaining the block rigidity, compared to when the number of grooves is increased within the side block, which is advantageous for achieving both block durability and rough road performance.

[0008] In this case, the recess depth of the first recess and the second recess relative to the surface of the side block is preferably 0.5 mm to 2.5 mm. The area of ​​the second recess is preferably 10% to 40% of the area of ​​the first recess. By setting the recess depth and size relationship of the recesses in this way, the shape of each recess and the size of the first recess and the second recess are well balanced, which is advantageous for achieving both block durability and rough road driving performance.

[0009] In the present invention, it is preferable that the groove width of the folded portion is smaller than the groove width of the connecting portion, which makes it easier to ensure block rigidity and is advantageous in achieving both block durability and rough road performance.

[0010] In the present invention, the groove depth of the curved side groove is preferably 0.5 mm to 3 mm. By setting the groove depth and the amount of recess in each portion in this manner, the curved side groove and the recess are well balanced, which is advantageous for achieving both block durability and rough road running performance.

[0011] In the present invention, the shoulder lug grooves may have groove bottom protrusions protruding from the groove bottom, which provides an edge effect and is advantageous in improving traction performance.

[0012] 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]

[0013] [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 diagram of a block group (shoulder block (side surface) and side block (front surface)) of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The configuration of the present invention will be described in detail below with reference to the accompanying drawings.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] As shown in Figs. 1 and 2, a pair of main grooves 10 are formed on the surface of the tread portion 1, extending all around the tire 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 30 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.

[0019] 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.

[0020] When the region adjacent to the shoulder region on the outer side in the tire width direction is defined as the 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 outer surface of the sidewall 2 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 on the outer side in the tire width direction at a position corresponding to 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 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 one of the plurality of shoulder lug grooves 11 arranged at intervals in the tire circumferential direction. One side block 13 and two or more shoulder blocks 12 (and one or more shoulder lug grooves 11 not connected to the side groove 14) are disposed between the shoulder lug grooves 11 and side grooves 14 connected in this way.

[0021] 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.

[0022] 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.

[0023] When a combination of two or more shoulder blocks 12 and one side block 13 described above is defined as block group B, in the present invention, a bent side groove 20 is formed on an extension line of a shoulder lug groove 11 arranged between a pair of shoulder blocks 12 included in block group B, the bent side groove 20 terminating within the side block 13. The bent side groove 20 has a bent shape including a connection portion 21 extending from an end position of the shoulder lug groove 12 toward the inside in the tire radial direction, and a turn-up portion 22 bent from an end portion on the inside in the tire radial direction of the connection portion 21 to one side in the tire circumferential direction and extending toward the outside in the tire radial direction.

[0024] In the tire of the present invention, the whole (block group B) consisting of the above-mentioned shoulder block 12 and side block 13 functions substantially as a large block, and the rigidity of the block having a sufficient volume can be secured, so that the block durability can be improved. On the other hand, since the bent side groove 20 having the above-mentioned structure is provided in the side block 13, the traction performance can be improved by its edge effect. In particular, the bent side groove 20 includes a connection portion 21 extending from the end position of the shoulder lug groove 11 toward the tire radially inward, and a turn-up portion 20 bending from the end portion of the connection portion 21 on the tire radially inner side to one side in the tire circumferential direction and extending toward the tire radially outward (i.e., extending in the opposite direction to the connection portion 21), so that the bent shape exerts an edge effect in various directions, and the traction performance can be effectively improved. In addition, since the bent side groove 20 terminates in the side block 13, the decrease in block rigidity due to the addition of a groove can be suppressed. These cooperations can achieve a high degree of both block durability and rough road running performance.

[0025] If the bent side groove 20 does not have the bent shape described above and simply extends linearly from the end of the shoulder lug groove 11, the groove length cannot be sufficiently secured and the traction performance cannot be sufficiently improved. If the bent side groove 20 does not terminate within the block, the side block will be divided and the block group B consisting of a combination of multiple shoulder blocks 12 and one side block 13 will not be formed, and therefore the block durability cannot be improved.

[0026] The groove depth of the bent side groove 20 is preferably 0.5 mm to 3 mm, more preferably 1 mm to 2 mm. By setting the groove depth in this range, the edge effect of the bent side groove 20 and the reduction in block rigidity due to the provision of the bent side groove 20 are well balanced, which is advantageous for achieving both block durability and rough road running performance. If the groove depth of the bent side groove 20 is less than 0.5 mm, it is difficult to ensure a sufficient edge effect because the groove depth is too small. If the groove depth of the bent side groove 20 exceeds 3 mm, it is difficult to ensure sufficient block rigidity. It is preferable that the connection portion 21 and the folded portion 22 constituting the bent side groove 20 are set to the same groove depth.

[0027] The bent side groove 20 preferably has a tapered shape in which the groove width gradually narrows from the end position of the shoulder lug groove 12 toward the terminal end. At least, the groove width of the folded portion 22 is preferably smaller than the groove width of the connecting portion 21. Even if the folded portion 22 approaches the connecting portion 21 due to the bent shape of the bent side groove 20, the groove width of the folded portion 22 is narrow, so that the block rigidity can be ensured, which is advantageous for achieving both block durability and rough road running performance. The maximum groove width of the bent side groove 20 (groove width at the position where it connects to the shoulder lug groove 12) is preferably 25 mm or less, more preferably 5 mm to 20 mm. In addition, the tip of the bent side groove 20 (i.e., the tip of the folded portion 22) is preferably acute-angled.

[0028] In the present invention, it is preferable to provide a first recess 31 that is recessed from the surface of the side block 13 and protrudes higher than the curved side groove 20 at a position adjacent to the other side in the tire circumferential direction of the connecting portion 21 (the side opposite to the direction in which the folded-back portion 22 is bent). It is also preferable to provide a second recess 32 that is recessed from the surface of the side block 13 and protrudes higher than the curved side groove 20 at a position adjacent to the outer side in the tire radial direction of the folded-back portion 22. By providing the first recess 31 and the second recess 32 in addition to the curved side groove 20 in this way, the unevenness of the surface of the side block 13 can be made more complex while maintaining the block rigidity compared to the case where the number of grooves is increased within the side block 13, which is advantageous for achieving both block durability and rough road driving performance.

[0029] The recessed amount of the first recess 31 and the second recess 32 with respect to the surface of the side block 13 is preferably 0.5 mm to 2.5 mm, more preferably 0.5 mm to 2 mm. By setting the recessed amount in this manner, the balance between the curved side groove 20 and each recess 31, 32 is good, which is advantageous for achieving both block durability and rough road running performance. If the recessed amount of the first recess 31 and the second recess 32 is less than 0.5 mm, sufficient unevenness is not added to the surface of the side block 13, and the effect of improving traction performance is limited. If the recessed amount of the first recess 31 and the second recess 32 exceeds 2.5 mm, the difference in depth with the curved side groove 20 is substantially eliminated, making it difficult to maintain sufficient block rigidity.

[0030] As described above, the first recess 31 and the second recess 32 are recessed from the surface of the side block 13, but are raised higher than the curved side groove 20, so that the recess amount of each recess is smaller than the groove depth of the curved side groove 20. In this case, the difference between the recess amount of each recess and the groove depth of the curved side groove 20 (i.e., the raised height of each recess from the groove bottom of the curved side groove 20) is preferably 0 mm to 3 mm, and more preferably 0 mm to 2 mm. This improves the uneven shape formed by each recess and the curved side groove 20, which is advantageous for achieving both block durability and rough road running performance.

[0031] Considering the positional relationship between the first recess 31 and the second recess 32, it is preferable that the area of ​​the second recess 32 adjacent to the folded portion 22 is smaller than that of the first recess 31 adjacent to the connecting portion 21 (i.e., the side closer to the shoulder block 12). Specifically, the area of ​​the second recess 32 is preferably 10% to 40%, more preferably 15% to 30%, of the area of ​​the first recess 31. This provides a good balance between the sizes of the first recess 31 and the second recess 32, which is advantageous for achieving both block durability and rough road running performance. If the area of ​​the second recess 32 is less than 10% of the area of ​​the first recess 31, the second recess 32 is too small, and the edge effect added by providing the second recess 32 cannot be expected to be sufficient. If the area of ​​the second recess 32 exceeds 40% of the area of ​​the first recess 31, the proportion of the first recess 31 and the second recess 32 in the side block 13 becomes large, making it difficult to maintain sufficient block rigidity.

[0032] The opening area of ​​the curved side groove 20 on the surface of the side block 13 is preferably 5% to 40%, more preferably 10% to 30%, of the surface area of ​​the side block 13 (the entire area including the curved side groove 20, the first recess 31, and the second recess 32). The total area of ​​the first recess 31 and the second recess 32 is preferably 5% to 40%, more preferably 15% to 30%, of the surface area of ​​the side block 13 (the entire area including the curved side groove 20, the first recess 31, and the second recess 32).

[0033] The groove bottom of the shoulder lug groove 11 disposed between a pair of shoulder blocks 12 included in the block group B may be provided with a groove bottom protrusion 33 protruding from the groove bottom. Similarly, the groove bottom of the other shoulder lug groove 11 (shoulder lug groove 11 located between two block groups B adjacent in the tire circumferential direction) may also be provided with a groove bottom protrusion 33. Providing the groove bottom protrusion 33 in this manner can further add an edge effect, which is advantageous for improving traction performance. It can also prevent stone trapping in the shoulder lug groove 11. The groove bottom protrusion 33 does not protrude over the entire width of the groove bottom of the shoulder lug groove 11, but rather protrudes only a part of the groove bottom of the shoulder lug groove 11 as shown in the figure. The width of the groove bottom protrusion 33 is preferably 10% to 40%, more preferably 15% to 25%, of the groove width of the shoulder lug groove 11. The protruding height of the groove bottom protrusion 33 is preferably 0.5 mm to 3 mm, more preferably 1 mm to 2 mm.

[0034] 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

[0035] Fifteen types of pneumatic tires, namely Conventional Example 1, Comparative Examples 1-2, and Examples 1-12, 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. The number of shoulder blocks adjacent to the radial outside of one side block, the presence or absence of bent side grooves, the groove depth of the bent side groove, the maximum width of the bent side groove, the presence or absence of a first recess adjacent to the connection portion of the bent side groove, the presence or absence of a second recess adjacent to the turn-back portion of the bent side groove, the depression amount of the first / second recesses, the ratio of the area of ​​the second recess to the area of ​​the first recess, and the presence or absence of a groove bottom protrusion of the shoulder lug groove were set as shown in Tables 1 and 2.

[0036] 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.

[0037] In the column of "Presence or Absence of Bent Side Groove" in Tables 1 and 2, the case where the bent side groove is not formed but a groove extending from the end position of the shoulder lug groove toward the tire radially inward and terminating within the side block is formed (Comparative Example 2) is described as "Straight side groove". In this case, for convenience, the groove depth and maximum width of the straight side groove are described in the columns of "Depth of Bent Side Groove" and "Maximum Width of Bent Side Groove".

[0038] The pneumatic tires were evaluated for rough road performance and block durability by the following evaluation methods, and the results are shown in Tables 1 and 2.

[0039] 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 rough road driving performance.

[0040] 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).

[0041] [Table 1]

[0042] [Table 2]

[0043] As is clear from Table 1, the pneumatic tires of Examples 1 to 12 improved rough-road running performance and block durability compared to Conventional Example 1, and achieved a good balance between these performances. On the other hand, Comparative Example 1 has a structure in which 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 rough-road running performance was not sufficiently obtained because the curved side groove was not provided. Comparative Example 2 had a straight side groove instead of a curved side groove, and therefore the rough-road running performance could not be sufficiently improved.

[0044] 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, When one side block is disposed at a position on the outer side in the tire width direction of two or more shoulder blocks adjacent to each other in the tire circumferential direction, and a combination of the two or more shoulder blocks and one side block is defined as a block group, a bent side groove is formed on an extension line of the shoulder lug groove disposed between a pair of the shoulder blocks included in the block group, the bent side groove terminating within the side block; a tire characterized in that the bent side groove includes a connection portion extending radially inward in the tire direction from an end position of the shoulder lug groove, and a turn-up portion bent to one side in the tire circumferential direction from an end portion on the radially inner side of the connection portion and extending radially outward in the tire direction. Invention [2] A tire as described in invention [1], characterized in that a first recess is formed adjacent to the other circumferential side of the connection portion, the first recess being recessed from the surface of the side block and raised higher than the bent side groove, and a second recess is formed adjacent to the radially outer side of the turned-up portion, the second recess being recessed from the surface of the side block and raised higher than the bent side groove. Invention [3] The tire according to invention [2], characterized in that the recess amounts of the first recess and the second recess with respect to the surface of the side block are 0.5 mm to 2.5 mm. Invention [4] The tire according to invention [2] or [3], wherein an area of ​​the second recess is 10% to 40% of an area of ​​the first recess. Invention [5] The tire according to any one of inventions [1] to [4], wherein the groove width of the folded-back portion is smaller than the groove width of the connecting portion. Invention [6] The tire according to any one of inventions [1] to [5], characterized in that the groove depth of the curved side groove is 0.5 mm to 3 mm. Invention [7] The tire according to any one of inventions [1] to [6], characterized in that the shoulder lug groove has a groove bottom protrusion protruding from the groove bottom. [Explanation of symbols]

[0045] 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 Side Groove 21 Connection 22 Folded section 31 First recess 32 Second recess 33 Groove bottom protrusion CL Tire Equator B Block Group

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, When one side block is disposed at a position on the outer side in the tire width direction of two or more shoulder blocks adjacent to each other in the tire circumferential direction, and a combination of the two or more shoulder blocks and one side block is defined as a block group, a bent side groove is formed on an extension line of the shoulder lug groove disposed between a pair of the shoulder blocks included in the block group, the bent side groove terminating within the side block; a tire characterized in that the bent side groove includes a connection portion extending radially inward in the tire direction from an end position of the shoulder lug groove, and a turn-up portion bent to one side in the tire circumferential direction from an end portion on the radially inner side of the connection portion and extending radially outward in the tire direction.

2. The tire described in claim 1, characterized in that a first recess is formed at a position adjacent to the other circumferential side of the connection portion, the first recess being recessed from the surface of the side block and raised higher than the bent side groove, and a second recess is formed at a position adjacent to the radially outer side of the folded-back portion, the second recess being recessed from the surface of the side block and raised higher than the bent side groove.

3. 3. The tire according to claim 2, wherein the recessed amount of the first recess and the second recess with respect to the surface of the side block is 0.5 mm to 2.5 mm.

4. 4. The tire according to claim 2, wherein an area of ​​the second recess is 10% to 40% of an area of ​​the first recess.

5. The tire according to any one of claims 1 to 3, characterized in that the groove width of the folded-back portion is smaller than the groove width of the connecting portion.

6. The tire according to any one of claims 1 to 3, characterized in that the groove depth of the curved side groove is 0.5 mm to 3 mm.

7. The tire according to any one of claims 1 to 3, characterized in that the shoulder lug groove has a groove bottom protrusion protruding from the groove bottom.

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