Pneumatic tire

Abstract

To provide a pneumatic tire having an annular side block on a sidewall, wherein the pneumatic tire enables improvement of soil ejection performance and traction performance on rough terrain, while securing the rigidity of the side block.SOLUTION: A tire 1 includes an annular side block 30 that protrudes from a sidewall reference surface 5a on at least one of a pair of sidewalls 5. A plurality of dimples 32, 33, and 34, each longer in the tire circumferential direction than in the tire radial direction, are formed in the side block. Each dimple has a radial inclined surface that is inclined with respect to a top surface 60 of the side block so as to continuously extend from the top surface and increase in depth in a direction away from the top surface in the tire radial direction. A shape of the side block in a side view of the tire is a shape repeated in the tire circumferential direction at an identical pitch. Two or more and six or fewer of the plurality of dimples are provided in the side block per one pitch in the side view of the tire.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire including a tread and a pair of sidewalls, wherein at least one of the pair of sidewalls includes an annular side block protruding from a sidewall reference plane.

Background Art

[0002] Conventionally, a side block protruding outward in the tire axial direction from a sidewall reference plane is provided on the side surface in the tire axial direction of a tire. The side block can improve the cut resistance performance for suppressing the occurrence of cut scars when stones, rocks, etc. collide with the sidewall.

[0003] For example, Patent Document 1 describes that a plurality of side protectors corresponding to side blocks are provided on the sidewall of the side surface in the tire axial direction so as to bulge outward in the tire axial direction, being divided in the tire circumferential direction. The side protector is provided with a groove, a notch, and a sipe.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in a tire for rough terrain driving or the like, it may be considered to provide an annular side block protruding from the sidewall reference plane over the entire circumference on the sidewall provided on the side surface in the tire axial direction. On the other hand, in a tire simply provided with an annular side block, there is room for improvement in terms of achieving both ensuring the rigidity of the side block and improving the soil discharge property and the traction performance on rough terrain.

[0006] An object of the present invention is to achieve both ensuring the rigidity of a side block and improving the earth-removing property and the traction performance on uneven ground in a pneumatic tire having an annular side block on a sidewall.

Means for Solving the Problems

[0007] The pneumatic tire according to the present invention includes a tread and a pair of sidewalls, and is a pneumatic tire in which at least one of the pair of sidewalls includes an annular side block protruding from a sidewall reference plane. In the side block, a plurality of dimples that are longer in the tire circumferential direction than in the tire radial direction are formed. Each of the dimples has a radially inclined surface inclined with respect to the top surface so as to be continuous from the top surface of the side block and increase in depth in a direction away from the top surface in the tire radial direction. The shape of the side block in a tire side view has a shape that is repeated in the tire circumferential direction at the same pitch. Two or more and six or less dimples per pitch are provided in the side block in a tire side view.

Effects of the Invention

[0008] According to the pneumatic tire of the present invention, in a pneumatic tire having an annular side block on a sidewall, it is possible to achieve both ensuring the rigidity of the side block and improving the earth-removing property and the traction performance on uneven ground.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0010] Hereinafter, with reference to the drawings, an example of an embodiment of a pneumatic tire according to the present invention will be described in detail. The embodiments described below are merely examples, and the present invention is not limited to the following embodiments.

[0011] FIG. 1 is a view of a part of the circumferential direction of a pneumatic tire 1 which is an example of an embodiment as seen from the outside in the tire axial direction. FIG. 2 is a view showing a tire contour shape in which the side blocks 30 are omitted in the meridian cross-section of the pneumatic tire 1. FIG. 3 is a view showing only a part of the tire circumferential direction of the side blocks 30 taken out from FIG. 1 and extending the tire circumferential direction in the left-right direction. FIG. 4 is a view showing the shape per pitch of the shape of the tire side view taken from FIG. 3. FIG. 5 is a cross-sectional view taken along line A-A of FIG. 3. FIG. 6 is a cross-sectional view taken along line B-B of FIG. 3. Hereinafter, "pneumatic tire 1" will be referred to as "tire 1".

[0012] The tire 1 includes a tread 10 which is a portion in contact with the road surface. The tread 10 has a tread pattern including a plurality of blocks such as shoulder blocks 2 and is formed annularly along the tire circumferential direction. A plurality of grooves 3 for partitioning the blocks are formed in the tread 10. In FIG. 2, the illustration of the grooves is omitted. The tread 10 has a ground contact end T (FIG. 2). In FIGS. 1, 3, and 4, the tire circumferential direction is indicated by X, the outside in the tire radial direction is indicated by Y1, and the inside in the tire radial direction is indicated by Y2.

[0013] Hereinafter, the structure of the tire 1 will be described with the part on one side in the tire axial direction as the center. The tire 1 may have a symmetrical shape on both sides in the tire axial direction with the center in the tire axial direction as the center, or the shape on the other side in the tire axial direction, for example, the shape of the side surface facing the axial direction on the other side in the tire axial direction may be different from that on one side in the tire axial direction.

[0014] At both ends in the tire axial direction, the tire 1 is provided with a pair of sidewalls 5 that are provided at the ends outside the tread 10 in the tire axial direction and bulge most outward in the tire axial direction, and a bead (not shown) that is fixed to the rim of the wheel. The sidewall 5 and the bead are formed in an annular shape along the tire circumferential direction. The sidewall 5 extends radially inward from both ends in the tire axial direction of the tread 10. As shown in FIG. 2, at the inner end in the radial direction Y of the tire 1, a rim strip 18 that forms the outer surface of the bead is provided adjacent to the sidewall 5.

[0015] The tire 1 is a pneumatic tire filled with air at a predetermined pressure. The tread 10 is composed of tread rubber. The sidewall 5 is composed of a different type of sidewall rubber from the tread rubber.

[0016] In this specification, unless otherwise specified, the dimensions of each part of the tire are the dimensions measured in the unloaded normal state where the unused tire is mounted on the regular rim and filled with air to the regular internal pressure.

[0017] The "ground contact end T" means both ends in the tire axial direction Z of the region that contacts the flat road surface when a load of 88% of the regular load at the regular internal pressure is applied in the state where the unused tire 1 is mounted on the regular rim and filled with air to the regular internal pressure.

[0018] Here, the "regular rim" is the rim defined by the tire standard, which is the "standard rim" in JATMA, the "Design Rim" in TRA, and the "Measuring Rim" in ETRTO. The "regular internal pressure" is the "maximum air pressure" in JATMA, the maximum value described in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" in TRA, and the "INFLATION PRESSURE" in ETRTO. The "regular load" is the "maximum load capacity" in JATMA, the maximum value described in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" in TRA, and the "LOAD CAPACITY" in ETRTO.

[0019] Tire 1 includes a carcass and a belt layer. The carcass is a cord layer covered with rubber and forms the framework of Tire 1 that withstands loads, impacts, air pressure, etc. The belt layer is a reinforcing band disposed between the tread rubber and the carcass. The belt layer strongly compresses the carcass to increase the rigidity of Tire 1. The belt layer is formed by a plurality of belts overlapping in the tire radial direction. Each belt is formed by covering a plurality of cords arranged in a direction inclined with respect to the tire circumferential direction with rubber. In adjacent belts, the cords are inclined in opposite directions with respect to the tire circumferential direction so that the cords of each other cross. The cords are formed of steel or the like.

[0020] Between the belt layer and the tread rubber, a belt reinforcing layer is provided that extends in the tire circumferential direction and covers the entire tire axial direction Z of the belt layer. The belt reinforcing layer is formed by covering cords extending substantially in the tire circumferential direction with rubber. The cords are formed of organic fibers or the like.

[0021] Further, as part of the rim strip rubber forming the rim strip 18, a rim protector 23 protruding outward in the tire axial direction is provided. The rim line 24 is provided annularly along the tire circumferential direction at the apex located at the outer end in the tire axial direction of the rim protector 23. The rim protector 23 has a function of protecting the rim from damage. The rim line 24 is a line for confirming with the gap from the rim that the tire 1 is properly mounted on the rim. In FIG. 2, the rim protector 23 is provided, but as shown by the two-dot chain line in FIG. 2, a configuration without the rim protector 23 may also be used. Even in this case, a rim line, which is a projection protruding outward in the tire axial direction and formed in an annular shape, is provided on the tire side surface for confirming that the tire 1 is properly mounted on the rim.

[0022] In this example, side blocks 30 shown in FIGS. 1, 3 to 6 are provided on the tire side surface 13, which is the outer surface in the tire axial direction Z on the inner side in the tire radial direction Y from the ground contact end T of the tread 10 and on the outer side in the tire radial direction Y from the rim line 24.

[0023] Specifically, as shown in FIGS. 1, 3 to 6, on the tire side surface 13, a side block 30, which is an annular raised portion protruding over the entire circumference toward the outer side in the tire axial direction from the sidewall reference surface 5a, which is the profile surface of the sidewall 5, is provided. The "sidewall reference surface 5a" means the surface of the sidewall 5 facing the outer side in the tire axial direction when the side block 30 is not formed. The side block 30 is provided along the tire circumferential direction. The side block 30 improves the cut resistance performance of the tire side surface 13. Further, by making the side block 30 continuous annularly over the entire circumference in the tire circumferential direction, the rigidity of the side block 30 can be ensured.

[0024] The tire 1 is suitable for, for example, a tire for a light truck. Note that light trucks include pickup trucks, sports utility vehicles (SUVs), etc. An example of the size of the tire 1 is LT275 / 60R20.

[0025] On the tire 1, a side rib 6 is formed near the tread 10 of the tire side surface 13. The side rib 6 is a convex portion protruding toward the outer side in the tire axial direction and is formed annularly along the tire circumferential direction. In the present embodiment, the side rib 6 is formed along the tire circumferential direction near the outer peripheral edge portion of the side block 30. The side rib 6 is disposed, for example, outside the tire maximum width position P (FIG. 2) in the outer side in the tire radial direction Y. In this specification, the "tire maximum width position P" means a position where the tire axial length is maximum on the sidewall reference plane 5a.

[0026] Further, a portion from the outer axial end of the surface of the shoulder block 2 facing the outer side in the tire radial direction Y to the side rib 6 is defined as a buttressless region, and a portion from the bead to the side rib 6 is defined as the sidewall 5. For this reason, the side block 30 is provided on the sidewall 5. Also, the inner radial end of the buttressless region and the outer radial end of the side block 30 are connected at substantially the same position in the tire axial direction via the side rib 6.

[0027] The buttressless region may be made of the same rubber as the tread 10 or may be made of different rubber. On the other hand, side blocks 30 having the same shape or different shapes from each other may be provided on a pair of sidewalls 5 on both sides in the tire axial direction. The tire 1 may be a tire without a specified mounting direction. On the other hand, the tire 1 may be configured such that the mounting direction is specified, and the side block 30 shown in FIGS. 1, 3 to 6 may be provided only on the outer axial surface of the portion on the outer side of the vehicle.

[0028] Hereinafter, the side block 30 will be described in detail. The side block 30 can be formed between the side rib 6 and the tire maximum width position P. In this case, it becomes easy to ensure good side traction performance and cut (protection) performance of the tire side surface 13.

[0029] The side block 30 has recesses 31 formed at a plurality of equally spaced positions in the tire circumferential direction on the radially inner edge so as to be recessed toward the outside in the tire radial direction. Thereby, the side traction performance can be improved. In this example, a stepped portion 31a is formed inside the recess 31 so that the depth is greater near the center in the tire circumferential direction, which is farther from the wall surface than near the wall surface of the side block 30.

[0030] Furthermore, a plurality of dimples 32, 33, 34 that are longer in the tire circumferential direction than in the tire radial direction are formed in the side block 30. Each of the dimples 32, 33, 34 is provided so as to be recessed at a plurality of positions on the top surface 60 facing the outside in the tire axial direction of the side block 30. Thereby, the soil discharge property on the tire side surface 13 can be improved. For example, since each of the dimples 32, 33, 34 is longer in the tire circumferential direction than in the tire radial direction, even when soil or mud enters each of the dimples 32, 33, 34 during traveling on muddy ground or the like, the soil discharge property of shaking off to the outside in the tire radial direction from each of the dimples 32, 33, 34 can be enhanced.

[0031] In addition, the shape of the side block 30 as viewed from the tire side has a shape that is repeated in the tire circumferential direction at the same pitch. For example, FIG. 4 shows the shape of one pitch when the shape is repeated in the tire circumferential direction in the side block 30. Further, two or more and six or less dimples 32, 33, 34 can be provided in the side block 30 per pitch in the tire side view. In FIG. 4, three dimples 32, 33, 34 are provided per pitch, but only two dimples, or four or more and six or less dimples may be provided in the side block 30 per pitch. In this way, two or more dimples 32, 33, 34 are provided per pitch, and an inclined surface is further provided inside as described later. Therefore, the amount of mud in the muddy ground that can be sheared within a predetermined range in the tire circumferential direction increases, so that the traction performance on uneven ground can be improved. Also, when driving on a rocky terrain, rocks are likely to catch on the end wall surface of the dimples in the tire circumferential direction, and this also improves the traction performance on uneven ground. In addition, it is possible to prevent the number of dimples from becoming excessive and the tire circumferential length of each dimple from becoming too small. For this reason, it becomes easier to exert an edge on rocks or the like on the end wall surface of each dimple in the tire circumferential direction, so that the traction performance on uneven ground can be further improved.

[0032] The plurality of dimples 32, 33, 34 are provided in two rows in the tire radial direction Y. Specifically, the plurality of dimples 32, 33, 34 are configured to include the outer row dimples 32, 33 and the inner row dimples 34 that are radially inward of the tire than the outer row. In the configuration of this example, as shown in FIGS. 1, 3, and 4, in a tire side view, with the center line c1 passing through the center in the tire radial direction as a boundary, the outer row dimples 32, 33 are arranged on the outer side in the tire radial direction, and the inner row dimples 34 are arranged on the inner side in the tire radial direction. In each of the outer row and inner row dimples 32, 33, 34, a plurality of dimples are arranged side by side along the tire circumferential direction. Thus, since the plurality of dimples 32, 33, 34 are provided in two rows in the tire radial direction Y, it becomes easier to suppress the extension of the cut damage of the tire with the dimples 32, 33, 34. Specifically, on the top surface of the side block 30, with a radially intermediate portion of the tire having a small radial length remaining, the dimples 32, 33, 34 are provided on both sides in the tire radial direction. Therefore, even if a cut damage occurs in the side block 30, it can be suppressed by a small cut damage, and the extension of the cut damage can be suppressed. For this reason, the cut resistance performance can be improved.

[0033] In the side block 30 of the tire 1, when a plurality of dimples are provided in two rows, the number of the above pitches is, for example, 40 or more and 60 or less.

[0034] In addition, in this example, the case where a plurality of dimples 32, 33, 34 divided into two rows are provided is described, but a configuration may be adopted in which a plurality of dimples are provided in only one row in the tire radial direction, or a plurality of dimples are provided in three or more rows.

[0035] The dimples 32 and 33 in the outer row are provided such that the first dimple 32 and the second dimple 33 with different shapes are alternately arranged in the tire circumferential direction X in a side view of the tire. The first dimple 32 has a trapezoidal shape in which the length in the tire circumferential direction X is larger at the inner end Y2 in the tire radial direction than at the outer end Y1 in the tire radial direction in a side view of the tire. The second dimple 33 has a trapezoidal shape in which the length in the tire circumferential direction X is larger at the outer end Y1 in the tire radial direction than at the inner end Y2 in the tire radial direction in a side view of the tire. The opening area of the first dimple 32 is larger than the opening area of the second dimple 33.

[0036] On the other hand, the dimples 34 in the inner row are provided such that a plurality of third dimples 34 are arranged in the tire circumferential direction X. The third dimple 34 has a substantially L-shaped configuration in which a narrow portion 36 having a length in the tire circumferential direction smaller than that of the wide portion 35 is connected to one side in the tire circumferential direction X of the wide portion 35 having a large length in the tire circumferential direction X at the outer side Y1 in the tire radial direction in a side view of the tire. In the inner row, one third dimple 34 is disposed between two adjacent recesses 31 in the tire circumferential direction X.

[0037] Each of the first dimple 32, the second dimple 33, and the third dimple 34 described above is longer in the tire circumferential direction X than in the tire radial direction. Further, inside each of the dimples 32, 33, and 34, there is a radially inclined surface that is continuous from the opening edge formed on the top surface 60 of the side block 30 and is inclined with respect to the top surface 60 such that the depth increases in a direction away from the top surface 60 in the tire radial direction.

[0038] Specifically, as shown in FIGS. 3 to 6, the first dimple 32 has an inner radial inclined surface 41 inclined with respect to the top surface 60 such that the depth increases in a direction away from the top surface 60 from the inner end Y2 in the tire radial direction to the outer end Y1 in the tire radial direction, and an outer radial inclined surface 42 inclined with respect to the top surface 60 such that the depth increases in a direction away from the top surface 60 from the outer end Y1 in the tire radial direction to the inner end Y2 in the tire radial direction. The inclination angle θ1 at which the inner radial inclined surface 41 is inclined with respect to the top surface 60 is smaller (shallower inclination) than the inclination angle θ2 at which the outer radial inclined surface is inclined with respect to the top surface 60. As a result, in the first dimple 32, the side where the depth is maximum in the tire radial direction is the outer side.

[0039] A bottom surface 43 substantially coinciding with the sidewall reference surface 5a is formed at the bottom of the first dimple 32. End wall surfaces 44 and 45 connected to the circumferential ends of the respective radial inclined surfaces 41, 42 and the bottom surface 43 are formed at both circumferential ends of the first dimple 32 on the inner side in the tire circumferential direction. Each of the end wall surfaces 44 and 45 is also inclined with respect to the top surface 60, similar to the radial inclined surfaces 41 and 42, but the inclination angle is larger (the inclination is steeper) than that of the inner radial inclined surface 41.

[0040] On the other hand, the second dimple 33 has an outer radial inclined surface 46 inclined with respect to the top surface 60 such that the depth increases in a direction away from the top surface 60 from the outer end Y1 in the tire radial direction to the inner end Y2 in the tire radial direction, and an inner radial inclined surface 47 inclined with respect to the top surface 60 such that the depth increases in a direction away from the top surface 60 from the inner end Y2 in the tire radial direction to the outer end Y1 in the tire radial direction. The inclination angle θ3 at which the outer radial inclined surface 46 is inclined with respect to the top surface 60 is smaller (shallower inclination) than the inclination angle θ4 at which the inner radial inclined surface 47 is inclined with respect to the top surface 60. As a result, in the second dimple 33, the side where the depth is maximum in the tire radial direction is the inner side.

[0041] Therefore, in the first dimple 32 and the second dimple 33 that form the outer row of dimples 32 and 33, the side where the depth is maximum in the tire radial direction is different.

[0042] At the bottom of the second dimple 33, a bottom surface 48 that substantially coincides with the sidewall reference plane 5a is formed. At both ends in the tire circumferential direction inside the second dimple 33, end wall surfaces 49, 50 that are connected to the circumferential edges of the respective radial inclined surfaces 46, 47 and the bottom surface 48 in the tire circumferential direction are formed. Each of the end wall surfaces 49, 50 is also inclined with respect to the top surface 60, similar to the radial inclined surfaces 46, 47, but the inclination angle is larger than that of the outer radial inclined surface 46 (the inclination is steeper).

[0043] As described above, by forming a plurality of dimples 32, 33 in the outer row, when driving on muddy ground, each dimple 32, 33 receives mud, and when the mud hits the end wall surfaces 44, 45, 49, 50 of the dimple 32, 33, the traction performance on uneven ground can be improved. Also, when driving on a rocky ground, the traction performance can be improved by the end wall surfaces 44, 45, 49, 50 of the dimple 32, 33 hitting the rock. Furthermore, the discharge property can be improved by the inclination of the radial inclined surfaces 41, 42, 46, 47.

[0044] Furthermore, between the first dimple 32 and the second dimple 33, in the tire radial direction, the sides where the depths of the radial inclined surfaces 41, 42, 46, 47 are maximum are different. Thereby, it becomes easier for mud to enter the dimples 32, 33 from both the outer side and the inner side in the tire radial direction, and it also becomes easier to discharge the mud. For example, in the first dimple 32, it becomes easier to take in and out mud from the inner side Y2 in the tire radial direction, and in the second dimple 33, it becomes easier to take in and out mud from the outer side Y1 in the tire radial direction. Therefore, further improvement in the discharge property and the traction performance can be achieved.

[0045] The third dimple 34 in the inner row has a substantially L-shaped bottom, and a bottom surface 51 whose width in the tire radial direction is larger than the bottom surfaces 43, 48 of the first and second dimples 32, 33 is formed, and a wall surface 52 continuous from the top surface 60 is connected around the bottom surface 51. The wall surface 52 is inclined with respect to the top surface 60, but the inclination angle is as large as that in the case of the wall surfaces 44, 45, 49, 50 at both ends in the tire circumferential direction of the first and second dimples 32, 33.

[0046] Also, among the plurality of dimples 32, 33, 34 provided in the side block 30, the number of dimples in the inner row is less than the number of dimples in the outer row. Further, as shown in FIG. 3, in a side view of the tire, between the circumferential centers L1 and L2 of the first dimple 32 and the second dimple 33, which are two dimples at both ends in the circumferential direction of the tire at an adjacent pitch in the outer row, the circumferential center L3 of the third dimple 34 in the inner row is located.

[0047] Also, the maximum circumferential length d1 (FIG. 3) of the third dimple 34 in the inner row is larger than the maximum circumferential length (d2) of the first dimple 32 and the second dimple 33 in the outer row. Thereby, the third dimple 34, which is a dimple on the side farther from the ground surface, can be enlarged, so that it is easier to exhibit the edge effect of the rock in the rocky ground. Thereby, the traction performance can be further improved.

[0048] Furthermore, at the opening edge of each of the plurality of dimples 32, 33, 34, at least a part of both end edges in the tire radial direction is along the tire circumferential direction X. For example, in the first dimple 32 and the second dimple 33, at the opening edge, all of the both end edges in the tire radial direction are along the tire circumferential direction X. In the third dimple 34, the inner end edge in the tire radial direction and the part excluding the stepped surface at the intermediate position in the tire circumferential direction X of the outer end edge in the tire radial direction are along the tire circumferential direction X. Thereby, it becomes easy to form a wall having a constant width in the tire radial direction along the tire circumferential direction X in a portion other than the dimples 32, 33, 34 of the side block 30. Thereby, the rigidity of the side block 30 can be increased.

[0049] Furthermore, the height of the side block 30 from the sidewall reference plane 5a gradually increases toward the inner side Y2 in the tire radial direction. For example, FIG. 5 shows a cross section at substantially the same position in the tire circumferential direction X. In FIG. 5, the height H1 of the wall surface 52 at the circumferential end of the tire from the bottom surface 51 in the third dimple 34 is greater than the height H2 of the wall surface 45 at the circumferential end of the tire from the bottom surface 43 in the first dimple 32. As a result, when the tire sinks deeper in muddy ground, a greater edge effect can be exerted, thereby suppressing the sinking.

[0050] Also, in a portion of the inner edge in the tire radial direction of the side block 30, excluding the opening peripheral edge of the recess 31, a raised portion is formed so that the height rapidly increases, and an inner rib 61 extending along the tire circumferential direction X is formed. The inner rib may be omitted.

[0051] The height of the side block 30 from the sidewall reference plane 5a is 3.0 mm or more and 5.0 mm or less over the entire tire radial direction.

[0052] Also, the maximum depth of each of the plurality of dimples 32, 33, 34 is 2.0 mm or more and 5.0 mm or less.

[0053] Furthermore, with respect to the tire section height Ht (FIG. 2), all of the first, second, and third dimples 32, 33, 34, which are a plurality of dimples, can be formed only in a range of 30% or more and 60% or less from the tire height position Ha at the center in the tire axial direction toward the inner side in the tire radial direction. In this case, as shown in FIG. 2, from the first tire radial position G1 at 30% of Ht from the tire height position Ha at the center in the tire axial direction toward the inner side in the tire radial direction, to the second tire radial position G2 at 60% of Ht from the tire height position Ha at the center in the tire axial direction toward the inner side in the tire radial direction, all of the first, second, and third dimples 32, 33, 34 are formed in the tire radial range (the range indicated by the arrow α in FIG. 2).

[0054] According to the above tire 1, in the tire 1 having the annular side block 30 on the sidewall 5, it is possible to achieve both ensuring the rigidity of the side block 30 and improving the earth removal property and the traction performance on uneven ground.

[0055] In the above, the case where the dimples 32 and 33 in the outer row are arranged on the tire radial outside of the center line c1 passing through the center in the tire radial direction and the dimple 34 in the inner row is arranged on the tire radial inside of the center line c1 has been described. On the other hand, the dimples in the inner row may be arranged on the tire radial inside of the dimples in the outer row, and both the dimples in the outer row and the inner row may be arranged only on one side in the tire radial direction of the center line c1.

[0056] The present disclosure will be further described by the following embodiments. Configuration 1: A pneumatic tire including a tread and a pair of sidewalls, at least one of the pair of sidewalls including an annular side block protruding from a sidewall reference plane, a plurality of dimples that are longer in the tire circumferential direction than in the tire radial direction are formed in the side block, each of the dimples has a radially inclined surface inclined with respect to the top surface so as to be continuous from the top surface of the side block and increase in depth in a direction away from the top surface in the tire radial direction, the shape of the side block in a tire side view has a shape that is repeated in the tire circumferential direction at the same pitch, two or more and six or less dimples per pitch are provided in the side block in a tire side view, A pneumatic tire. Configuration 2: The plurality of dimples are provided separately in two or more rows in the tire radial direction, The pneumatic tire according to Configuration 1. Configuration 3: The plurality of dimples include the dimples in the outer row and the dimples in the inner row that are radially inside the tire than the outer row, and the number of dimples in the inner row is smaller than that in the outer row. In a side view of the tire, the center in the tire circumferential direction of the dimples in the inner row is located between the centers in the tire circumferential direction of two dimples at both ends in the tire circumferential direction at an adjacent pitch of the outer row. The pneumatic tire according to Configuration 2. Configuration 4: The plurality of dimples include the dimples in the outer row and the dimples in the inner row that are radially inside the tire than the outer row. The maximum length in the tire circumferential direction of the dimples in the inner row is larger than the maximum length in the tire circumferential direction of the dimples in the outer row. The pneumatic tire according to Configuration 2 or Configuration 3. Configuration 5: The plurality of dimples are at least some of the dimples provided side by side in the tire circumferential direction, and include a first dimple and a second dimple that are alternately formed in the tire circumferential direction. For the first dimple and the second dimple, the sides where the depth is maximum are different in the tire radial direction. The pneumatic tire according to any one of Configurations 1 to 4. Configuration 6: At the opening edge of each of the plurality of dimples, at least a part of both end edges in the tire radial direction is along the tire circumferential direction. The pneumatic tire according to any one of Configurations 1 to 5. Configuration 7: The height of the side block from the sidewall reference plane gradually increases toward the inside in the tire radial direction. The pneumatic tire according to any one of Configurations 1 to 6. Configuration 8: The height of the side block from the sidewall reference plane is 3.0 mm or more and 5.0 mm or less throughout the tire radial direction. The pneumatic tire according to Configuration 7. Configuration 9: The maximum depth of each of the plurality of dimples is 2.0 mm or more and 5.0 mm or less. The pneumatic tire according to any one of Configurations 1 to 8. Configuration 10: The plurality of dimples are formed only in a range of 30% or more and 60% or less from the tire height position at the center in the tire axial direction toward the inner side in the tire radial direction with respect to the tire section height. The pneumatic tire according to any one of Configurations 1 to 9.

Explanation of Signs

[0057] 1 Pneumatic tire (tire), 2 Shoulder block, 3 Groove, 5 Sidewall, 5a Sidewall reference plane, 6 Side rib, 10 Tread, 13 Tire side surface, 18 Rim strip, 23 Rim protector, 24 Rim line, 30 Side block 31 Recess, 32 First dimple, 33 Second dimple, 34 Third dimple, 41 Inner radial inclined surface, 42 Outer radial inclined surface, 43 Bottom surface, 44, 45 End wall surface, 46 Outer radial inclined surface, 47 Inner radial inclined surface, 48 Bottom surface, 49, 50 End wall surface, 51 Bottom surface, 60 Top surface, 61 Inner rib, P Tire maximum width position, T Ground contact end.

Claims

1. A pneumatic tire comprising a tread and a pair of sidewalls, at least one of the pair of sidewalls including an annular side block protruding from a sidewall reference plane, wherein a plurality of dimples that are longer in the tire circumferential direction than in the tire radial direction are formed in the side block, each of the dimples has a radially inclined surface inclined with respect to the top surface so as to be continuous from the top surface of the side block and to increase in depth in a direction away from the top surface in the tire radial direction, the shape of the side block in a side view of the tire has a shape that is repeated in the tire circumferential direction at the same pitch, two or more and six or less of the plurality of dimples are provided in the side block per pitch in a side view of the tire, A pneumatic tire.

2. The plurality of dimples are provided in two or more rows in the tire radial direction, The pneumatic tire according to claim 1.

3. The plurality of dimples include the dimples in an outer row and the dimples in an inner row that is radially inside the tire than the outer row, and the dimples in the inner row having a smaller number of dimples than the outer row, in a side view of the tire, the circumferential center of the dimples in the inner row is located between the circumferential centers of the two dimples at both ends in the tire circumferential direction in an adjacent pitch of the outer row, The pneumatic tire according to claim 2.

4. The plurality of dimples include the dimples in an outer row and the dimples in an inner row that is radially inside the tire than the outer row, the maximum circumferential length of the dimples in the inner row is larger than the maximum circumferential length of the dimples in the outer row, The pneumatic tire according to claim 2.

5. The plurality of dimples are at least some of the dimples provided side by side in the tire circumferential direction, and include a first dimple and a second dimple that are alternately formed in the tire circumferential direction, in the first dimple and the second dimple, the side where the depth is maximum is different in the tire radial direction, The pneumatic tire according to claim 1.

6. At least a part of both end edges in the tire radial direction is along the tire circumferential direction at the opening edge of each of the plurality of dimples, The pneumatic tire according to claim 1.

7. The height of the side block from the sidewall reference plane gradually increases toward the inner side in the tire radial direction. The pneumatic tire according to claim 1.

8. The height of the side block from the sidewall reference plane is 3.0 mm or more and 5.0 mm or less over the entire tire radial direction. The pneumatic tire according to claim 7.

9. The maximum depth of each of the plurality of dimples is 2.0 mm or more and 5.0 mm or less. The pneumatic tire according to claim 1.

10. The plurality of dimples are formed only in a range of 30% or more and 60% or less from the tire height position at the center in the tire axial direction toward the inner side in the tire radial direction with respect to the tire section height. The pneumatic tire according to claim 1.

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