Pneumatic tire

Abstract

To provide a pneumatic tire capable of maintaining high traction performance by suppressing chipping of a side block.SOLUTION: A pneumatic tire comprising a tread, a sidewall 3, and a bead, wherein the sidewall 3 includes a side block 20 protruding outward in a tire axial direction, and the side block 20 includes at least a main block 30 extending in a tire radial direction, the main block 30 includes the protruding region 31 having the highest protruding height in the main block 30, and the inner inclined region 32 which is connected to the inner end of the protruding region 31 in the tire radial direction and of which the protruding height gradually decreases as the distance from the protruding region 31 increases, and the length of the protruding region 31 in the tire radial direction is equal to or greater than the length of the inner inclined region 32 in the tire radial direction.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a pneumatic tire. [Background technology]

[0002] Conventionally, pneumatic tires having a tread, sidewalls, and beads have been widely known as off-road tires used on muddy or sandy terrain. Patent Document 1 discloses a pneumatic tire having a plurality of side blocks on the sidewalls that protrude axially outward. Providing the side blocks on the sidewalls can achieve high traction performance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-3948 Summary of the Invention [Problem to be solved by the invention]

[0004] As a result of the inventors' investigations, it became clear that when a large load is applied to the side blocks during running, damage such as chipping may occur, particularly in the radially inner end portion of the side blocks. The occurrence of chipping is particularly pronounced when the side blocks protrude significantly. Chipping of the side blocks is undesirable because it reduces the traction performance of the tire.

[0005] An object of the present invention is to provide a pneumatic tire that can suppress chipping of side blocks and maintain high traction performance. [Means for solving the problem]

[0006] One example of an embodiment of a pneumatic tire of the present invention is a pneumatic tire having a tread, sidewalls, and beads, wherein the sidewalls have side blocks that protrude axially outward, and the side blocks include at least main blocks that extend radially of the tire, and the main blocks have a protruding region that has the highest protruding height among the main blocks, and an inner inclined region that is connected to the radially inner end of the protruding region and whose protruding height gradually decreases with increasing distance from the protruding region, and the radial length of the protruding region is equal to or greater than the radial length of the inner inclined region. [Effects of the Invention]

[0007] According to the pneumatic tire of the present invention, chipping of the side blocks can be suppressed, and as a result, a pneumatic tire that can maintain high traction performance can be provided. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram schematically illustrating a cross section of a pneumatic tire as an example of an embodiment. [Figure 2] 1 is a perspective view of a pneumatic tire as an example of an embodiment. [Figure 3] 1 is a side view of a pneumatic tire as an example of an embodiment. [Figure 4] 1 is a schematic diagram of a side view of a sidewall included in a pneumatic tire that is an example of an embodiment. FIG. [Figure 5] FIG. 5 is a cross-sectional view taken along line AA in FIG. 4. [Figure 6] FIG. 5 is a cross-sectional view taken along line BB in FIG. 4. [Figure 7] FIG. 5 is a cross-sectional view taken along line CC in FIG. 4. [Figure 8] DD line cross section of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an example of an embodiment of a pneumatic tire according to the present invention will be described in detail with reference to the drawings. The embodiment described below is merely an example, and the present invention is not limited to the following embodiment. Furthermore, the present invention includes configurations that are formed by selectively combining the respective components of the multiple embodiments and modified examples described below.

[0010] FIG. 1 is a schematic diagram showing a cross section of a pneumatic tire 1 according to this embodiment. As shown in FIG. 1, the pneumatic tire 1 includes a tread 2, which is the portion that comes into contact with the road surface, a sidewall 3 that forms the tire's side surface, and a bead 4, which is the portion that is fixed to the wheel rim. The pneumatic tire 1 is suitable as a mud terrain tire (MT tire) or a rugged terrain tire (RT tire) that is suitable for off-road driving on muddy roads, rocky areas, etc. The pneumatic tire 1 is mounted on, for example, light trucks such as pickup trucks and sport utility vehicles (SUVs).

[0011] The pneumatic tire 1 is a point-symmetric tire that does not require a specific mounting direction on a vehicle, and the tread pattern and tire side surface shape remain unchanged regardless of the mounting direction. The tread pattern and tire side surface shape of the pneumatic tire 1 are rotated 180° on either side of the tire equator CL. The equator CL is an imaginary line that runs along the tire circumferential direction and passes through the axial center of the tread 2.

[0012] A plurality of blocks and grooves separating the blocks are formed in the tread 2. The tread 2 has, for example, a plurality of circumferential grooves 10A, 10B, and 10C extending along the tire circumferential direction. The tread 2 also has shoulder blocks 11 on both axial sides of the tire, which are positioned axially outward of the circumferential grooves 10A and 10C.

[0013] The sidewalls 3 are disposed on both axial sides of the tread 2 and are provided in an annular shape along the tire circumferential direction. The sidewalls 3 are the parts of the pneumatic tire 1 that protrude most axially outward, and are gently curved so as to be convex axially outward. That is, the sidewalls 3 have a position P on their outer surface that is the maximum tire width (hereinafter referred to as the "maximum tire width position").

[0014] The pneumatic tire 1 has a side rib 5 formed near the tread 2 on the side of the tire. The side rib 5 is a convex portion that protrudes axially outward and is formed in a ring shape along the tire circumferential direction. In this embodiment, the portion from the axially outer end of the surface of the shoulder block 11 facing radially outward to the side rib 5 is defined as a buttress region, and the portion from the bead 4 to the side rib 5 is defined as a sidewall 3.

[0015] The tread 2 and the sidewall 3 are generally made of different types of rubber. The buttress region may be made of the same rubber as the tread 2 or a different rubber than the tread 2.

[0016] The bead 4 is disposed on the radially inner side of the sidewall 3 and is fixed to the wheel rim. The bead 4 has a bead core 4A and a bead filler 4B. The bead core 4A is an annular member made of a steel bead wire that extends around the entire circumference of the tire and is embedded in the bead 4. The bead filler 4B is an annular hard rubber member that has a tapered tip that extends outward in the radial direction of the tire and extends around the entire circumference of the tire.

[0017] The pneumatic tire 1 further includes a carcass 6 that is bridged between the pair of beads 4, and an inner liner 7 that is arranged inside the carcass 6 in the tire radial direction.

[0018] The carcass 6 is laid between a pair of beads 4 and is secured by being folded back around the bead core 4A. The carcass 6 is made up of at least one carcass ply. The carcass ply is made up of carcass cords made of organic fibers that are covered with coating rubber.

[0019] The inner liner 7 covers the inner surface of the tire between the pair of beads 4. The inner liner 7 is made of air-permeable resistant rubber and has the function of maintaining the air pressure of the pneumatic tire 1.

[0020] The pneumatic tire 1 further includes a belt 8 disposed on the outer side of the carcass 6 in the tire radial direction, and a cap ply 9 covering the outer side of the belt 8 in the tire radial direction. The cap ply 9 has a function of reinforcing the belt 8.

[0021] The belt 8 is disposed on the outer side of the top of the carcass 6 in the tire radial direction, and is provided overlapping the outer peripheral surface of the carcass 6. The belt 8 is formed of a belt ply in which cords arranged in a direction inclined with respect to the tire circumferential direction are coated with rubber. There are no particular limitations on the material of the cords of the belt 8, and examples include organic fibers such as polyester, rayon, nylon, and aramid, and metals such as steel. In this embodiment, the belt 8 is formed of two belt plies 8A and 8B. The number of belt plies is not particularly limited, and may be one, or three or more.

[0022] The shoulder blocks 11, buttress regions, and sidewalls 3 of the pneumatic tire 1 will be described in detail below with reference to FIGS. 2 and 3. FIG. 2 is a perspective view of the pneumatic tire 1, and FIG. 3 is a left side view of the pneumatic tire 1. Note that FIGS. 2 and 3 show enlarged views of the shoulder blocks 11, buttress regions, and sidewalls 3. In the following, as shown in FIGS. 2 and 3, a first direction in the tire circumferential direction may be referred to as the "X1 direction," and a second direction may be referred to as the "X2 direction." Furthermore, a direction facing outward in the tire radial direction may be referred to as the "Y1 direction," and a direction facing inward in the tire radial direction may be referred to as the "Y2 direction."

[0023] [Shoulder Block] As shown in Figures 2 and 3, the shoulder blocks 11 are blocks arranged on the axially outer side of the tread 2 (see Figure 1). The shoulder blocks 11 include first shoulder blocks 12 and second shoulder blocks 13, which have different shapes. The first shoulder blocks 12 and second shoulder blocks 13 are separated by lateral grooves 14, 15 and arranged alternately around the tire circumferential direction. In this embodiment, the circumferential lengths of the first shoulder blocks 12 and second shoulder blocks 13 on the axially outer side of the tire are approximately the same. However, the configuration of the shoulder blocks 11 is not limited to this, and one type of block may be arranged circumferentially at intervals.

[0024] Buttress Area First buttress blocks 16 and second buttress blocks 17 that protrude axially outward are provided on the side surfaces 12A, 13A of the first shoulder blocks 12 and second shoulder blocks 13, respectively. By providing the first buttress blocks 16 and second buttress blocks 17 on the side surfaces 12A, 13A of the first shoulder blocks 12 and second shoulder blocks 13, respectively, unevenness is formed in the buttress region in the circumferential direction of the tire. When traveling on muddy or sandy ground, mud and stones are trapped by these unevenness, achieving high traction performance. The first buttress blocks 16 and second buttress blocks 17 do not come into contact with the ground during normal traveling on flat roads.

[0025] In this embodiment, the tire radially inner ends (Y2 direction ends) of the first buttress block 16 and the second buttress block 17 are connected to the side rib 5. Note that the Y2 direction ends of the first buttress block 16 and the second buttress block 17 do not necessarily have to be connected to the side rib 5.

[0026] Furthermore, the tire radially outer ends (Y1 direction ends) of the first buttress blocks 16 are disposed radially outward (on the Y1 direction side) of the tire radially outer ends of the second buttress blocks 17. In other words, the tire radial length of the first buttress blocks 16 is greater than the tire radial length of the second buttress blocks 17. In this case, it is easy to achieve high traction performance. The tire radial length of the first buttress blocks 16 is, for example, 1.2 times or more, and may be 1.5 times or more, the tire radial length of the second buttress blocks 17.

[0027] The circumferential length of the first buttress block 16 on the Y1 direction side is the same as the circumferential length of the first shoulder block 12. In other words, the first buttress block 16 is formed over the entire circumferential length of the side surface 12A of the first shoulder block 12 on the Y1 direction side.

[0028] The first buttress block 16 has a recess 16A recessed toward the X1 direction in a portion located on the inner side in the tire radial direction (Y2 direction side). In other words, the tire circumferential length of the first buttress block 16 on the Y2 direction side is smaller than the tire circumferential length of the first shoulder block 12.

[0029] The tire circumferential length of the first buttress block 16 at the Y2 direction end of the first buttress block 16 may be, for example, 20% to 70% or less, or 25% to 50% or less, of the tire circumferential length of the first buttress block 16 at the Y1 direction end of the first buttress block 16. The tire radial length of the recess 16A may be, for example, 20% to 80% or less, or 30% to 70% or less of the tire radial length of the first buttress block 16. By having the Y2 direction side of the first buttress block 16 have a shape that is recessed toward the X1 direction, high traction performance can be achieved.

[0030] The circumferential length of the second buttress block 17 on the Y1 direction side is the same as the circumferential length of the second shoulder block 13, similar to the first buttress block 16. In other words, the second buttress block 17 is formed over the entire circumferential length of the side surface 13A of the second shoulder block 13 on the Y1 direction side.

[0031] Similarly to the first buttress blocks 16, the second buttress blocks 17 have recesses 17A recessed toward the X1 direction in a portion located on the inner side (Y2 side) in the tire radial direction. In other words, the tire circumferential length of the second buttress blocks 17 on the Y2 side is smaller than the tire circumferential length of the second shoulder blocks 13.

[0032] The tire circumferential length of the second buttress block 17 at the Y2 direction end of the second buttress block 17 may be, for example, 20% to 80% or less, or 30% to 70% or less, of the tire circumferential length of the second buttress block 17 at the Y1 direction end of the second buttress block 17. Furthermore, the tire radial length of the recess 17A may be, for example, 20% to 80% or less, or 30% to 70% or less of the tire radial length of the second buttress block 17. By having the Y2 direction side of the second buttress block 17 recessed toward the X1 direction, high traction performance can be achieved, similar to the first buttress block 16.

[0033] [Sidewall] 2 and 3, the sidewall 3 is provided with a plurality of side blocks 20 that protrude axially outward from a profile surface 3A of the sidewall 3. The "profile surface 3A" of the sidewall 3 refers to the surface of the sidewall 3 that faces axially outward when no side blocks 20 are formed.

[0034] The side blocks 20 include first side blocks 21 and second side blocks 22 which have different shapes. The first side blocks 21 and the second side blocks 22 are arranged alternately in the tire circumferential direction.

[0035] The radial length of the first side blocks 21 is greater than the radial length of the second side blocks 22. That is, the Y2 end of the first side blocks 21 is located closer to the Y2 side than the Y2 end of the second side blocks 22. As a result, an area where no second side blocks 22 are provided is formed between adjacent first side blocks 21 in the tire circumferential direction on the Y2 side of the first side blocks 21. This area is prone to trapping mud and stones when traveling on muddy or sandy ground. This allows for better traction performance.

[0036] The first side blocks 21 are positioned so as to overlap the first buttress blocks 16 in the tire radial direction. The Y2-side portions of the first side blocks 21 are positioned so as to overlap not only the first buttress blocks 16 but also the lateral grooves 14 and the second buttress blocks 17 in the tire radial direction. In other words, the Y2-side portions of the first side blocks 21 protrude toward the X1 direction, and the tire circumferential length of the Y2-side portions of the first side blocks 21 is greater than the tire circumferential length of the Y1-side portions of the first side blocks 21. The tire circumferential length of the Y1-side ends of the first side blocks 21 is, for example, substantially the same as the tire circumferential length of the first buttress blocks 16 at their inner ends in the Y1 direction.

[0037] The block end of the first side block 21 may be formed perpendicular to the profile surface 3A, or may be inclined so that the height of the block gradually decreases. In this embodiment, the block end of the first side block 21 has an inclined slope 21A so that the height of the block gradually decreases, and the inclined slope 21A is formed so as to be curved near the boundary with the profile surface 3A.

[0038] Each first side block 21 is an integrated block formed by connecting one first main block 30 extending in the tire radial direction and one first sub-block 40 extending in the tire radial direction. The first main block 30 is the block that protrudes the most among the side blocks 20. The first sub-block 40 is, for example, provided on the X2 direction side of the first main block 30 and has a protruding height smaller than that of the first main block 30. In other words, a step extending in the tire radial direction is formed at the boundary between the first main block 30 and the first sub-block 40. The first sub-block 40 serves to reinforce the strength of the first main block 30. In other words, the provision of the first sub-block 40 improves the strength and durability of the first main block 30, thereby more significantly exhibiting the effects of the first main block 30 described below.

[0039] The Y1 end of the first main block 30 is connected to the side rib 5. The first main block 30 is disposed opposite the first buttress block 16 across the side rib 5. The tire circumferential length of the first main block 30 at the Y1 end is the same as the tire circumferential length of the first buttress block 16 at the Y2 end.

[0040] The Y1-direction end of the first sub-block 40 is connected to the side rib 5. The first sub-block 40 is disposed opposite a recess 16A provided in the first buttress block 16, with the side rib 5 interposed therebetween.

[0041] The second side blocks 22 are provided at positions overlapping with the second buttress blocks 17 in the tire radial direction. The second side blocks 22 are not provided at positions overlapping with the first buttress blocks 16 and the lateral grooves 14, 15 in the tire radial direction. The tire circumferential length of the Y2 direction portion of the second side blocks 22 decreases as it goes toward the Y2 direction. The tire circumferential length of the Y1 direction end of the second side blocks 22 is, for example, approximately the same as the tire circumferential length of the second buttress blocks 17 at their inner ends in the Y1 direction.

[0042] The block end of the second side block 22 may be formed perpendicular to the profile surface 3A, similar to the block end of the first side block 21, or may be inclined so that the height of the block gradually decreases. In this embodiment, the block end of the second side block 22 has an inclined slope 22A so that the height of the block gradually decreases, and the inclined slope 22A is formed so as to be curved near the boundary with the profile surface 3A.

[0043] Each second side block 22 is an integrated block formed by connecting one second main block 50 extending in the tire radial direction and one second sub-block 60 extending in the tire radial direction. The second sub-block 60 is, for example, provided on the X2 direction side of the second main block 50 and has a smaller protruding height than the second main block 50. In other words, a step extending in the tire radial direction is formed at the boundary between the second main block 50 and the second sub-block 60. Similar to the first sub-block 40, the second sub-block 60 serves to reinforce the strength of the second main block 50. In other words, the provision of the second sub-block 60 improves the strength and durability of the second main block 50, thereby more significantly exhibiting the effects of the second main block 50 described below.

[0044] The Y1-direction end of the second main block 50 is connected to the side rib 5. The second main block 50 is disposed opposite the second buttress block 17 across the side rib 5. The tire circumferential direction length of the second main block 50 at the Y1-direction end is the same as the tire circumferential direction length of the second buttress block 17 at the Y2-direction end.

[0045] The Y1-direction end of the second sub-block 60 is connected to the side rib 5. The second sub-block 60 is disposed opposite a recess 17A provided in the second buttress block 17, with the side rib 5 interposed therebetween.

[0046] The first side block 21 and the second side block 22 will be described in detail below with reference to Figures 4 to 8. Figure 4 is a schematic side view of the sidewall 3, Figure 5 is a cross-sectional view taken along line AA in Figure 4, Figure 6 is a cross-sectional view taken along line BB in Figure 4, Figure 7 is a cross-sectional view taken along line CC in Figure 4, and Figure 8 is a cross-sectional view taken along line DD in Figure 4.

[0047] [First side block] 4, the first main block 30 constituting the first side block 21 has a shape in which the Y2 direction portion protrudes toward the X1 direction. Specifically, the block end of the first main block 30 on the X1 direction side is formed in a substantially straight line in a front view along the tire radial direction on the Y1 direction side.

[0048] Furthermore, the block end of the first main block 30 on the X1 side has a bending point at the tire radial middle of the first main block 30. The block end of the first main block 30 on the X1 side is formed substantially linearly in a front view along a direction inclined toward the X1 direction with respect to the tire radial direction, on the Y2 side of the bending point. The inclination angle of the block end of the first main block 30 on the X1 side with respect to the tire radial direction is, for example, 20° to 70°, or may be 30° to 60°. By forming the block end of the first main block 30 on the X1 side so that it is inclined toward the X1 direction with respect to the tire radial direction, mud and stones are more likely to get caught on the first main block 30 when traveling on muddy or sandy ground. This allows for better traction performance.

[0049] Furthermore, the block end of the first main block 30 on the X1 direction side is formed in a substantially linear shape in a front view along the tire radial direction near the Y2 direction end of the first main block 30. Note that the shape of the first main block 30 is not limited to the above-described shape.

[0050] The block end of the first main block 30 on the X2 direction side is formed so that a middle portion of the first main block 30 in the tire radial direction protrudes toward the X2 direction in front view. In other words, the X2 direction end of the first main block 30 is located at a middle portion of the first main block 30 in the tire radial direction.

[0051] As shown in FIGS. 4 and 5 , the first main block 30 has a protruding region 31, which has the highest protruding height in the first main block 30, located in the tire radial middle portion. The first main block 30 also has an inner inclined region 32, located on the Y2 side of the protruding region 31, whose protruding height gradually decreases with increasing distance from the protruding region 31 in the tire radial direction. The first main block 30 also has an outer inclined region 33, located on the Y1 side of the protruding region 31, whose protruding height gradually decreases with increasing distance from the protruding region 31 in the tire radial direction, and an outer uniform region 34, whose protruding height is approximately uniform. That is, the first main block 30 has, in order from the Y1 end of the first main block 30 toward the Y2 side, the outer uniform region 34, the outer inclined region 33, the protruding region 31, and the inner inclined region 32. In this specification, the "protruding height" of a block refers to the length from the profile surface 3A along the normal direction to the profile surface 3A.

[0052] The protruding region 31 is the part of the first main block 30 that has the substantially highest protruding height. The protruding height of the protruding region 31 is approximately uniform throughout the entire protruding region 31. Because the protruding region 31 has the substantially highest protruding height of the first main block 30, it is a part that is likely to catch mud or stones when traveling on muddy or sandy ground. In other words, by providing the protruding region 31, high traction performance can be achieved.

[0053] The protruding height of the protruding region 31 is, for example, 5 mm or more, and preferably 7 mm or more. In this case, mud and stones are more likely to be caught in the protruding region 31 when traveling on muddy or sandy ground, making it easier to achieve higher traction performance. Furthermore, the protruding height of the protruding region 31 is, for example, 20 mm or less, and preferably 18 mm or less. In this case, it becomes easier to reduce the air resistance of the tire. Therefore, the protruding height of the protruding region 31 is, for example, 5 mm or more and 20 mm or less, and preferably 7 mm or more and 18 mm or less.

[0054] The inner inclined region 32 is contiguous with the Y2-direction end of the protruding region 31. In the inner inclined region 32, for example, the protruding height decreases linearly with increasing distance from the protruding region 31. In this embodiment, the slope on the Y2-direction side of the inner inclined region 32 near the Y2-direction end 32A of the inner inclined region 32 is formed to be curved.

[0055] Here, the radial length of the protruding region 31 is equal to or greater than the radial length of the inner inclined region 32. In this specification, the radial length of each region (similarly for blocks, etc.) means the length along the radial direction of the tire from the Y1 end to the Y2 end of the region in front view.

[0056] As a result of studies by the inventors, it has become clear that the Y2-direction end of the protruding region 31 is prone to damage such as chipping during driving. Therefore, by providing the inner inclined region 32 on the Y2-direction side of the protruding region 31, chipping at the Y2-direction end of the protruding region 31 can be suppressed. Furthermore, by making the tire radial length of the protruding region 31 equal to or greater than the tire radial length of the inner inclined region 32, mud and stones are more likely to get caught in the protruding region 31 when driving on muddy or sandy ground. As a result, high traction performance can be achieved. In other words, the configuration of the present invention can suppress chipping in the protruding region 31 while achieving high traction performance, thereby maintaining high traction performance.

[0057] The radial length of the protruding region 31 may be equal to or greater than the radial length of the inner inclined region 32, but is preferably 1.1 to 3.0 times, and more preferably 1.2 to 2.5 times, the radial length of the inner inclined region 32. In this case, high traction performance is more easily achieved.

[0058] The length of the protruding region 31 in the tire radial direction is, for example, 20% to 80% and preferably 30% to 70% of the length of the first main block 30 in the tire radial direction. In this case, high traction performance is more easily achieved.

[0059] The length of the inner inclined region 32 in the tire radial direction is, for example, 10% to 40% and preferably 15% to 35% of the length of the first main block 30 in the tire radial direction. In this case, chipping of the protruding region 31 can be further suppressed.

[0060] The outer inclined region 33 is connected to the Y1-direction end of the protruding region 31. In the outer inclined region 33, similar to the inner inclined region 32, for example, the protruding height decreases linearly with increasing distance from the protruding region 31.

[0061] Here, the radial length of the protruding region 31 is preferably equal to or greater than the radial length of the outer inclined region 33. Research by the inventors has revealed that chipping and other damage may occur even at the Y1-direction ends of the protruding region 31 during driving. Therefore, by providing the outer inclined region 33 on the Y1-direction side of the protruding region 31, chipping at the Y1-direction ends of the protruding region 31 can be suppressed. Furthermore, by making the radial length of the protruding region 31 equal to or greater than the radial length of the outer inclined region 33, mud and stones are more likely to get caught in the protruding region 31 when driving on muddy or sandy ground. As a result, high traction performance can be achieved.

[0062] The radial length of the protruding region 31 may be equal to or greater than the radial length of the outer inclined region 33, but is preferably 1.1 to 3.0 times, and more preferably 1.2 to 2.5 times, the radial length of the outer inclined region 33. In this case, high traction performance is more easily achieved.

[0063] The length of the outer inclined region 33 in the tire radial direction is, for example, 10% to 40% and preferably 15% to 35% of the length of the first main block 30 in the tire radial direction. In this case, chipping of the protruding region 31 can be further suppressed.

[0064] The outer uniform region 34 is contiguous to the Y1-direction end of the outer inclined region 33. The Y1-direction end of the outer uniform region 34 constitutes the Y1-direction end of the first main block 30 and is contiguous to the side rib 5. The protruding height of the outer uniform region 34 is, for example, 80% or less, or may be 60% or less, of the protruding height of the protruding region 31. The radial length of the outer uniform region 34 is, for example, 5% or more and 30% or less, or may be 5% or more and 20% or less, of the radial length of the first main block 30. Note that the first main block 30 does not necessarily have an outer uniform region 34. In this case, the Y1-direction end of the outer inclined region 33 is contiguous to the side rib 5.

[0065] 5, the first main block 30 is preferably arranged so that an end 32A on the Y2 side of the inner inclined region 32, which is the Y2 end of the first main block 30, does not overlap with the tire maximum width position P. In this embodiment, the end 32A of the first main block 30 is arranged on the Y2 side of the tire maximum width position P. Note that the "tire maximum width position P" refers to the position on the profile surface 3A of the sidewall 3 where the axial length of the tire is at its maximum.

[0066] The tire maximum width point P is a portion that is likely to receive loads during running. Therefore, by positioning the Y2-side end 32A of the inner inclined region 32 so that it does not overlap with the tire maximum width point P, damage such as cracks to the sidewall 3 can be suppressed. In other words, if the Y2-side end 32A of the inner inclined region 32 is positioned so that it overlaps with the tire maximum width point P, the sidewall 3 will be less likely to flex near the tire maximum width point P, making the sidewall 3 more susceptible to damage such as cracks.

[0067] Furthermore, it is more preferable that the end portion 32A of the first main block 30 is positioned so as not to overlap with the tire maximum width position P, and is positioned within a length range equivalent to 20% of the tire cross-sectional height H (see FIG. 1) centered on the tire maximum width position P. In this case, high traction performance can be achieved, and damage such as cracks in the sidewall 3 can be further suppressed.

[0068] If the Y2-side end 32A of the inner inclined region 32 is positioned further toward the Y1 side than the range, the radial length of the first main blocks 30 becomes shorter, making it difficult for mud or stones to get caught on the first main blocks 30 when traveling on muddy or sandy ground. As a result, it becomes difficult to achieve high traction performance. Furthermore, if the Y2-side end 32A of the inner inclined region 32 is positioned further toward the Y2 side than the range, the sidewall 3 becomes less flexible, making it more susceptible to damage such as cracks in portions of the sidewall 3 where the side blocks 20 are not formed.

[0069] 4, the first sub-blocks 40 constituting the first side blocks 21 are provided on the X2 direction side of the first main blocks 30 and have a smaller protruding height than the first main blocks 30. The first sub-blocks 40 have a shape in which the tire circumferential length decreases toward the Y2 direction. The tire circumferential length of the first sub-blocks 40 at the Y2 direction end of the first sub-blocks 40 is, for example, 10% to 50%, or may be 20% to 40%, of the tire circumferential length of the first main blocks 30 at the Y2 direction end of the first sub-blocks 40.

[0070] The Y2 end of the first sub-block 40 is preferably disposed on the Y2 side of the Y2 end of the protruding region 31 of the first main block 30. In other words, the first sub-block 40 is preferably disposed so as to overlap the entire area of ​​the protruding region 31 of the first main block 30 in the tire circumferential direction. As described above, the Y2 end of the protruding region 31 is a portion where chipping is likely to occur during running. Therefore, by disposing the Y2 end of the first sub-block 40 on the Y2 side of the Y2 end of the protruding region 31, it is possible to further suppress the occurrence of chipping at the Y2 end of the protruding region 31. As a result, it is possible to further maintain high traction performance.

[0071] In the present embodiment, the Y2 end of the first sub-block 40 is located on the Y1 side of the Y2 end of the inner inclined region 32 of the first main block 30. In other words, the tire radial length of the first sub-block 40 is shorter than the tire radial length of the first main block 30. Note that the Y2 end of the first sub-block 40 may be located at a position overlapping the Y2 end of the inner inclined region 32 in the tire circumferential direction, or may be located on the Y2 side of the Y2 end of the inner inclined region 32.

[0072] As shown in FIG. 6 , in this embodiment, the first sub-block 40 has a protruding region 41 in the tire radial middle portion, which has the highest protruding height of the first sub-block 40. The first sub-block 40 also has, on the Y2 side of the protruding region 41, an inner inclined region 42 whose protruding height gradually decreases with increasing distance from the protruding region 41, and an inner uniform region 43 whose protruding height is generally uniform. The first sub-block 40 also has, on the Y1 side of the protruding region 41, an outer inclined region 44 whose protruding height gradually decreases with increasing distance from the protruding region 41, and an outer uniform region 45 whose protruding height is generally uniform. That is, the first sub-block 40 has, in order from the Y1 end of the first sub-block 40 toward the Y2 side, the outer uniform region 45, the outer inclined region 44, the protruding region 41, the inner inclined region 42, and the inner uniform region 43.

[0073] The shape of the first sub-block 40 is not limited to this. For example, the first sub-block 40 may have a substantially uniform thickness in the tire radial direction. When the first sub-block 40 has the protruding region 41, the inner inclined region 42, and the outer inclined region 44, chipping of the first sub-block 40 tends to be suppressed, and the strength and durability of the first main block 30 can be easily improved.

[0074] The protruding region 41 is the portion of the first sub-block 40 that has substantially the highest protruding height. The protruding height of the protruding region 41 is approximately uniform throughout the entire protruding region 41. The protruding height of the protruding region 41 is, for example, 20% to 70% of the protruding height of the protruding region 31 of the first main block 30, and preferably 30% to 60%.

[0075] The protruding region 41 is provided at a position overlapping the protruding region 31 of the first main block 30 in the tire circumferential direction. In this case, chipping of the protruding region 31 of the first main block 30 can be further suppressed, making it possible to maintain high traction performance. In this embodiment, the Y1 end of the protruding region 41 is provided at a position overlapping the Y1 end of the protruding region 31 of the first main block 30 in the tire circumferential direction. In addition, the Y2 end of the protruding region 41 is provided on the Y1 side of the Y2 end of the protruding region 31 of the first main block 30. In other words, the tire radial length of the protruding region 41 is shorter than the tire radial length of the protruding region 31 of the first main block 30.

[0076] The inner inclined region 42 is contiguous with the Y2-direction end of the protruding region 41. For example, the protruding height of the inner inclined region 42 decreases linearly with increasing distance from the protruding region 41. In the present embodiment, the Y2-direction end of the inner inclined region 42 is provided at a position overlapping in the tire circumferential direction with the Y2-direction end of the protruding region 31 of the first main block 30. In other words, the sum of the tire radial length of the protruding region 41 and the tire radial length of the inner inclined region 42 is approximately the same as the tire radial length of the protruding region 31 of the first main block 30.

[0077] The inner uniform region 43 is contiguous with the Y2-direction end of the inner inclined region 42. The protruding height of the inner uniform region 43 is, for example, 80% or less, or may be 60% or less, of the protruding height of the protruding region 41. As described above, the Y2-direction end of the inner uniform region 43 is located closer to the Y1-direction side than the Y2-direction end 32A of the inner inclined region 32 of the first main block 30.

[0078] The outer inclined region 44 is contiguous with the Y1-direction end of the protruding region 41. In the outer inclined region 44, the protruding height linearly decreases with increasing distance from the protruding region 41, similar to, for example, the inner inclined region 42. In this embodiment, the Y1-direction end of the outer inclined region 44 is located closer to the Y2-direction side than the Y1-direction end of the outer inclined region 33 of the first main block 30.

[0079] The outer uniform region 45 is contiguous with the Y1-direction end of the outer inclined region 44. The protruding height of the outer uniform region 45 is, for example, 80% or less of the protruding height of the protruding region 41, and may be 60% or less. The protruding height of the outer uniform region 45 may be the same as or different from the protruding height of the inner uniform region 43. In this embodiment, the protruding height of the outer uniform region 45 is greater than the protruding height of the inner uniform region 43.

[0080] Here, the length in the tire radial direction of the protruding region 41 is preferably greater than the length in the tire radial direction of the inner inclined region 42 and the length in the tire radial direction of the outer inclined region 44. In this case, it becomes easier to improve the strength and durability of the first main block 30.

[0081] The tire radial length of the protruding region 41 may be, for example, 5% to 50%, or 10% to 40%, of the tire radial length of the first sub-block 40. Furthermore, the tire radial length of the protruding region 41 may be, for example, 1.1 to 3.0 times, or 1.2 to 2.5 times, the tire radial length of the inner inclined region 42 and the tire radial length of the outer inclined region 44.

[0082] The tire radial direction length of the inner inclined region 42 and the tire radial direction length of the outer inclined region 44 are, for example, 10% to 40% of the tire radial direction length of the first sub-block 40, and preferably 15% to 35%. In this case, chipping of the protruding region 41 can be further suppressed.

[0083] [Second side block] 4, the second main block 50 constituting the second side block 22 has a shape in which the tire circumferential length decreases toward the Y2 direction. Specifically, the block end of the second main block 50 on the X1 direction side is formed in a substantially straight line in a front view so as to extend along the tire radial direction.

[0084] Furthermore, the block end of the second main block 50 on the X2 side is formed in a generally linear shape in a front view along a direction inclined toward the X1 direction with respect to the tire radial direction. The inclination angle of the block end of the second main block 50 on the X2 side with respect to the tire radial direction is, for example, 10° to 60°, or may be 20° to 50°.

[0085] 4 and 7 , like the first main block 30, the second main block 50 has a protruding region 51 in the tire radial middle portion, which has the highest protruding height among the second main blocks 50. The second main block 50 also has an inner inclined region 52 on the Y2 side of the protruding region 51, whose protruding height gradually decreases with increasing distance from the protruding region 51 in the tire radial direction. The second main block 50 also has an outer inclined region 53 on the Y1 side of the protruding region 51, whose protruding height gradually decreases with increasing distance from the protruding region 51 in the tire radial direction, and an outer uniform region 54 whose protruding height is approximately uniform. That is, the second main block 50 has, in order from the Y1 end of the second main block 50 toward the Y2 side, the outer uniform region 54, the outer inclined region 53, the protruding region 51, and the inner inclined region 52.

[0086] The protruding region 51 is the part of the second main block 50 that has substantially the highest protruding height. The protruding height of the protruding region 51 is approximately uniform throughout the entire protruding region 51. Like the protruding region 31 of the first main block 30, the protruding region 51 is a part that is likely to catch mud or stones when traveling on muddy or sandy ground. In other words, providing the protruding region 51 can achieve high traction performance.

[0087] The protruding height of the protruding region 51 is, for example, 4 mm or more, and preferably 6 mm or more. In this case, mud and stones are more likely to be caught in the protruding region 51 when traveling on muddy or sandy ground, making it easier to achieve higher traction performance. Furthermore, the protruding height of the protruding region 51 is, for example, 20 mm or less, and preferably 18 mm or less. In this case, it is easier to reduce the air resistance of the tire. Therefore, the protruding height of the protruding region 51 is, for example, 4 mm or more and 20 mm or less, and preferably 6 mm or more and 18 mm or less. The protruding height of the protruding region 51 may be the same as or different from the protruding height of the protruding region 31 of the first main block 30. In this embodiment, the protruding height of the protruding region 51 is smaller than the protruding height of the protruding region 31 of the first main block 30.

[0088] The inner inclined region 52 is connected to the Y2-direction end of the protruding region 51. In the inner inclined region 52, for example, the protruding height decreases linearly with increasing distance from the protruding region 51.

[0089] The outer inclined region 53 is connected to the Y1-direction end of the protruding region 51. In the outer inclined region 53, similar to the inner inclined region 52, for example, the protruding height decreases linearly with increasing distance from the protruding region 51.

[0090] Here, the radial length of the protruding region 51 is equal to or greater than the radial length of the inner inclined region 52, as in the case of the first main block 30. As described above, chipping is likely to occur at the Y2 end of the protruding region 51 during running. Therefore, by providing the inner inclined region 52 on the Y2 side of the protruding region 51, chipping at the Y2 end of the protruding region 51 can be suppressed. Furthermore, by making the radial length of the protruding region 51 equal to or greater than the radial length of the inner inclined region 52, mud and stones are more likely to get caught in the protruding region 51 when running on muddy or sandy ground. As a result, high traction performance can be achieved. In other words, the configuration of the present invention can suppress chipping of the protruding region 51 while achieving high traction performance, thereby maintaining high traction performance.

[0091] As with the first main block 30, the radial length of the protruding region 51 is preferably equal to or greater than the radial length of the outer inclined region 53. As described above, chipping may occur even at the Y1 end of the protruding region 51 during driving. Therefore, by providing the outer inclined region 53 on the Y1 side of the protruding region 51, chipping on the Y1 side of the protruding region 51 can be suppressed. Furthermore, by making the radial length of the protruding region 51 equal to or greater than the radial length of the outer inclined region 53, mud and stones are more likely to get caught in the protruding region 51 when driving on muddy or sandy ground. As a result, high traction performance can be achieved.

[0092] In the present embodiment, the radial length of the protruding region 51 is substantially the same as the radial length of the inner inclined region 52 and the radial length of the outer inclined region 53. Note that the radial length of the protruding region 51 may be greater than the radial length of the inner inclined region 52 and the radial length of the outer inclined region 53.

[0093] The length of the protruding region 51 in the tire radial direction is, for example, 20% to 80% of the length of the second main block 50 in the tire radial direction, and more preferably 30% to 70%. In this case, high traction performance is more easily achieved.

[0094] The tire radial direction length of the inner inclined region 52 and the outer inclined region 53 is, for example, 10% to 40% of the tire radial direction length of the second main block 50, and preferably 15% to 35%. In this case, chipping of the protruding region 51 can be further suppressed.

[0095] The outer uniform region 54 is contiguous to the Y1-direction end of the outer inclined region 53. The Y1-direction end of the outer uniform region 54 constitutes the Y1-direction end of the second main block 50 and is contiguous to the side rib 5. The protruding height of the outer uniform region 54 is, for example, 80% or less, or may be 60% or less, of the protruding height of the protruding region 51. The radial length of the outer uniform region 54 is, for example, 5% or more and 30% or less, or may be 5% or more and 20% or less, of the radial length of the second main block 50. Note that the second main block 50 does not necessarily have an outer uniform region 54. In this case, the Y1-direction end of the outer inclined region 53 is contiguous to the side rib 5.

[0096] As shown in FIG. 4, the second sub-block 60 constituting the second side block 22 is provided on the X2 direction side of the second main block 50, and has a smaller protruding height than the second main block 50.

[0097] The Y2-direction end of the second sub-block 60 is disposed on the Y2-direction side of the Y2-direction end of the second main block 50. In other words, the tire radial direction length of the second sub-block 60 is greater than the tire radial direction length of the second main block 50.

[0098] The second sub-block 60 is connected to the entire block end of the second main block 50 on the X2 side and to most of the block end of the second main block 50 on the Y2 side. Chipping is likely to occur near the Y2 end of the second main block 50 during running. Therefore, by connecting the second sub-block 60 to most of the block end of the second main block 50 on the Y2 side, it is possible to suppress chipping near the Y2 end of the second main block 50.

[0099] 8, in this embodiment, the second sub-block 60 has, on the Y1 side, a protruding region 61 whose protruding height is the highest in the second sub-block 60. The second sub-block 60 also has, on the Y2 side of the protruding region 61, an inner inclined region 62 whose protruding height gradually decreases with increasing distance from the protruding region 61, and an inner uniform region 63 whose protruding height is approximately uniform. In other words, the second sub-block 60 has, in order from the Y1 end of the second sub-block 60 toward the Y2 side, the protruding region 61, the inner inclined region 62, and the inner uniform region 63.

[0100] The shape of the second sub-block 60 is not limited to this. For example, the second sub-block 60 may have a substantially uniform thickness in the tire radial direction. Similarly to the first sub-block 40, the second sub-block 60 may have an outer inclined region on the Y1 direction side of the protruding region 61, whose protruding height gradually decreases with increasing distance from the protruding region 61.

[0101] The protruding region 61 is the part of the second sub-block 60 that has substantially the highest protruding height. The protruding height of the protruding region 61 is approximately uniform throughout the entire protruding region 61. The protruding height of the protruding region 61 is, for example, 20% to 70% of the protruding height of the protruding region 51 of the second main block 50, and preferably 30% to 60%.

[0102] The protruding region 61 is provided at a position overlapping in the tire circumferential direction with the outer uniform region 54 of the second main block 50. The Y1-direction end of the protruding region 61 constitutes the Y1-direction end of the second sub-block 60 and is connected to the side rib 5. Note that a portion of the protruding region 61 may be provided at a position overlapping in the tire circumferential direction with the outer inclined region 53 or the protruding region 51 of the second main block 50.

[0103] The inner inclined region 62 is contiguous with the Y2-direction end of the protruding region 61. For example, the protruding height of the inner inclined region 62 decreases linearly with increasing distance from the protruding region 61. In this embodiment, the inner inclined region 62 is provided at a position overlapping with the outer inclined region 53 of the second main block 50 in the tire circumferential direction. Note that a portion of the inner uniform region 63 may be provided at a position overlapping with the outer uniform region 54 or the protruding region 51 of the second main block 50 in the tire circumferential direction.

[0104] In the present embodiment, the tire radial length of the protruding region 61 is substantially the same as the tire radial length of the inner inclined region 62. Note that the tire radial length of the protruding region 61 may be greater than the tire radial length of the inner inclined region 62. The tire radial length of the protruding region 61 may be, for example, 10% to 50% of the tire radial length of the second sub-block 60, or 15% to 40%.

[0105] The inner uniform region 63 is contiguous with the Y2-direction end of the inner inclined region 62. The protruding height of the inner uniform region 63 is, for example, 80% or less of the protruding height of the protruding region 61, and may be 60% or less.

[0106] The inner uniform region 63 has a shape that is bent toward the X1 direction from the Y2 direction side. The Y1 direction portion of the inner uniform region 63 is connected to the block end of the second main block 50 on the X2 direction side. The Y2 direction portion of the inner uniform region 63 is connected to the block end of the second main block 50 on the Y2 direction side. This makes it possible to prevent chipping from occurring near the Y2 direction end of the second main block 50.

[0107] As described above, the pneumatic tire 1 of this embodiment has the first side blocks 21 and the second side blocks 22 in the sidewall 3. The first side blocks 21 include the first main blocks 30 extending in the tire radial direction, and the second side blocks 22 include the second main blocks 50 extending in the tire radial direction. The first main blocks 30 and the second main blocks 50 each have a protruding region 31, 51 having the highest protruding height among the main blocks, and an inner inclined region 32, 52 that is connected to the Y2-direction end of the protruding region 31 and whose protruding height gradually decreases with increasing distance from the protruding region 31, 51. The tire radial lengths of the protruding regions 31, 51 are equal to or greater than the tire radial lengths of the inner inclined regions 32, 52, respectively.

[0108] According to the above configuration, mud and stones are more likely to get caught in the protruding regions 31, 51 when traveling on muddy or sandy ground. As a result, high traction performance can be achieved. Furthermore, by providing the inner inclined regions 32, 52 on the Y2 side of the protruding regions 31, 51, chipping can be suppressed in the regions on the Y2 side of the protruding regions 31, 51, where chipping is generally more likely to occur. In other words, chipping in the protruding regions 31, 51 can be suppressed while achieving high traction performance, thereby maintaining high traction performance.

[0109] The above-described embodiment can be modified within the scope of the present invention. For example, in the above-described embodiment, the side block 20 includes the first side block 21 and the second side block 22. However, the side block 20 may include only one of the first side block 21 and the second side block 22. In other words, the sidewall 3 may include only one of the first side block 21 and the second side block 22.

[0110] In the above embodiment, the first side block 21 includes the first main block 30 and the first sub-block 40, and the second side block 22 includes the second main block 50 and the second sub-block 60, but the configuration of the first side block 21 and the second side block 22 is not limited to this. For example, the first side block 21 may include only the first main block 30 and not the first side block 21. Similarly, the second side block 22 may include only the second main block 50 and not the second sub-block 60. [Explanation of symbols]

[0111] 1 pneumatic tire, 2 tread, 3 sidewall, 3A profile surface, 4 bead, 4A bead core, 4B bead filler, 5 side rib, 6 carcass, 7 inner liner, 8 belt, 8A, 8B belt ply, 9 cap ply, 10A, 10B, 10C circumferential groove, 11 shoulder block, 12 first shoulder block, 12A side, 13 second shoulder block, 13A side, 14, 15 lateral groove, 16 first buttress block, 16A, 17A recess, 17 second buttress block, 20 side block, 21 first side block, 21A, 22A slope, 22 second side block, 30 first main block, 31, 41, 51, 61 protruding area, 32, 42, 52, 62 inner slope area, 32A end, 33, 44, 53 Outer inclined region, 34, 45, 54 outer uniform region, 40 first sub-block, 43, 63 inner uniform region, 50 second main block, 60 second sub-block, P maximum tire width position.

Claims

1. A pneumatic tire having a tread, sidewalls, and beads, The sidewall has a side block protruding axially outward, The side blocks include at least a main block extending in the tire radial direction, The main block comprises: a protruding region having the highest protruding height in the main block; an inner inclined region that is connected to an inner end of the protruding region in the tire radial direction and whose protruding height gradually decreases with increasing distance from the protruding region; and a radial length of the protruding region of the pneumatic tire that is equal to or greater than a radial length of the inner inclined region of the pneumatic tire;

2. the main block further includes an outer inclined region that is connected to an outer end of the protruding region in the tire radial direction and whose protruding height gradually decreases with increasing distance from the protruding region, The pneumatic tire according to claim 1 , wherein a length in the tire radial direction of the protruding region is equal to or greater than a length in the tire radial direction of the outer inclined region.

3. The pneumatic tire according to claim 1 , wherein an inner end side in the tire radial direction of each of the main blocks protrudes toward one side in the tire circumferential direction.

4. The pneumatic tire according to claim 1 , wherein the length of the protruding region in the tire radial direction is 20% to 80% of the length of the main block in the tire radial direction.

5. The pneumatic tire according to claim 1 , wherein the length of the inner inclined region in the tire radial direction is 10% to 40% of the length of the main block in the tire radial direction.

6. The side blocks include first side blocks and second side blocks that are alternately arranged in the tire circumferential direction, The pneumatic tire according to claim 1 , wherein a length in the tire radial direction of the second side block is smaller than a length in the tire radial direction of the first side block.

7. The pneumatic tire according to claim 1 , wherein the side block further includes a sub-block connected to the main block on the other side in the tire circumferential direction and having a protruding height smaller than that of the main block.

8. The pneumatic tire according to claim 7 , wherein an inner end in the tire radial direction of the sub-block is positioned radially inward of an inner end in the tire radial direction of the protruding region of the main block.

9. The pneumatic tire according to claim 1 , wherein an inner end of each of the main blocks in the tire radial direction is disposed so as not to overlap a maximum width position of the tire.

10. The pneumatic tire according to claim 9 , wherein an inner end of each of the main blocks in the tire radial direction is disposed within a length range equivalent to 20% of a tire cross-sectional height, with the tire maximum width position as a center.

Images