pneumatic tires

Abstract

To provide a pneumatic tire that facilitates making both of traction performance and protection performance good.SOLUTION: A tire 1 includes a tread 10, and a plurality of side protectors 60 which are positioned on a radially inner side relative to a shoulder block 40A provided in the tread 10 and positioned outermost on a vehicle and which are positioned at an interval in a circumferential direction while projecting to an outer side in a width direction. A circumferential length of the side protector 60 is set longer than a circumferential length of the shoulder block 40A. The shoulder block 40A has a plurality of blocked recesses 70, which are positioned at an interval in the circumferential direction and are open on the outer side in the width direction. A step part 71 of a shallower depth than a bottom 73 of the blocked recesses 70 is arranged in at least part of a peripheral edge part of the blocked recesses 70 at its bottom.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] A conventional pneumatic tire is described in Patent Document 1. The sidewall of this pneumatic tire has a main body and a side protector that protrudes axially outward from a portion of the main body. The side protector protects a portion of the main body from the outside in the width direction. The side protector prevents foreign objects, such as stones, flying toward the side of the tire when the vehicle is traveling on rough roads from striking the main body and damaging it. The side protector has a recess that opens radially. This recess is provided to increase traction when the vehicle is traveling on muddy ground and increase driving force when the vehicle is traveling on rough roads. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6786927 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned pneumatic tire, if the area of ​​the recessed portion is increased in an attempt to improve traction performance, the protection performance of the tire sidewalls will decrease. On the other hand, if the area of ​​the recessed portion is decreased in an attempt to improve protection performance of the tire sidewalls, the traction performance will decrease. Therefore, an object of the present invention is to provide a pneumatic tire that can easily improve both traction performance and protection performance. [Means for solving the problem]

[0005] The pneumatic tire of the present invention comprises a tread and a plurality of protrusions that are located radially inward of an outermost block that is located at the outermost position of the vehicle and that protrude outward in the width direction, and are spaced apart circumferentially, the circumferential length of each protrusion being longer than the circumferential length of the outermost block, the protrusions being spaced apart circumferentially and having a plurality of blocked recesses that open outward in the width direction, and at least a portion of the peripheral edge of the bottom of each blocked recess is provided with a step that is shallower in depth than the bottom of the blocked recess. [Effects of the Invention]

[0006] According to the present invention, the circumferential dimension of the protrusion is larger than the circumferential dimension of the outermost block. Furthermore, a step is provided on the peripheral edge of the bottom surface of each of the two or more blocking recesses provided in the protrusion. Therefore, the circumferential dimension of the protrusion can be increased, and at least a portion of the peripheral edge of the bottom surface of each blocking recess provided in the protrusion is also protected by the step, effectively preventing foreign objects such as pebbles from colliding with the thin-walled bottom of the blocking recess. This results in excellent protection performance. Furthermore, since the protrusion has two or more blocking recesses, the traction performance of the protrusion can be excellent. Therefore, according to the present invention, it is easy to achieve two opposing effects that are in a trade-off relationship with each other, i.e., both protection performance and traction performance. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a half cross-sectional view including the radial direction and width direction of a pneumatic tire according to one embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view of a portion of a pneumatic tire as viewed from the vehicle outer side in the width direction. [Figure 3] FIG. 2 is a perspective view of a portion of a pneumatic tire as viewed from the vehicle inner side in the width direction. [Figure 4] 3 is an enlarged perspective view of the peripheral regions of two side protectors adjacent in the circumferential direction in FIG. 2. FIG. [Figure 5]1 is an enlarged plan view of the periphery of a side protector 1 of a pneumatic tire as viewed from outside a vehicle. [Figure 6] FIG. 6 is a cross-sectional view taken along the line XX in FIG. 5. DETAILED DESCRIPTION OF THE INVENTION

[0008] Embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. It is anticipated that, when multiple embodiments and variations are included below, new embodiments can be constructed by appropriately combining their characteristic features. In the following examples, the same components are denoted by the same reference numerals in the drawings, and redundant description will be omitted. The drawings include schematic diagrams, and the dimensional ratios of the length, width, height, and other dimensions of each component do not necessarily match between different drawings. Among the components described below, components not recited in the independent claims representing the highest concept are optional components and are not essential components. In the following description, the width direction refers to the width direction of the pneumatic tire 1, the radial direction refers to the radial direction of the pneumatic tire 1, and the circumferential direction refers to the circumferential direction of the pneumatic tire 1. The width direction, radial direction, and circumferential direction are perpendicular to each other. In the following description, when the terms "outside of a vehicle" and "inside of a vehicle" are used without explanation, they are defined as being in a state in which the pneumatic tire 1 is mounted on a vehicle.

[0009] FIG. 1 is a half cross-sectional view including the radial direction and width direction of a pneumatic tire 1 according to one embodiment of the present invention. As shown in FIG. 1, the pneumatic tire (hereinafter simply referred to as tire) 1 includes a tread 10, a pair of shoulders 11, a pair of sidewalls 12, and a pair of beads 13. The tread 10 is disposed in the center in the width direction and includes a contact surface 10a that comes into contact with the road surface. The tread 10 is made of, for example, crosslinked rubber. A plurality of grooves 24 is provided on the outer peripheral surface of the tread 10. As is well known, the plurality of grooves 24 serve to drain rainwater that has entered between the road surface and the tire 1, thereby ensuring a contact area between the road surface and the tire 1.

[0010] The grooves 24 include, for example, a plurality of main grooves 24a extending in the circumferential direction and a plurality of lateral grooves 24b, 24c (see FIGS. 2 and 3) extending in a direction intersecting the main grooves 24a. The grooves 24 define a plurality of blocks. In the example shown in FIG. 1, the tread 10 has shoulder blocks 40A, 40B arranged in the circumferential direction as blocks. The shoulder blocks 40A are located on the outer side of the vehicle (the right side in the width direction in FIG. 1) and are arranged in a row with a circumferential gap between them. The shoulder block 40A constitutes the outermost block located at the outermost position of the vehicle. The shoulder blocks 40B are located on the inner side of the vehicle (the left side in the width direction in FIG. 1) and are arranged in a row with a circumferential gap between them.

[0011] The tread 10 further has a center rib 30 provided in the center in the width direction and a plurality of mediate blocks 50A, 50B. The plurality of mediate blocks 50A are arranged in a row at intervals in the circumferential direction between the center rib 30 and the shoulder blocks 40A. The plurality of mediate blocks 50B are arranged in a row at intervals in the circumferential direction between the center rib 30 and the shoulder blocks 40B. The center rib 30 is provided on the tire equator along the circumferential direction. Note that the various blocks included in the tire of the present disclosure are not limited to those shown in FIG. 1. The tire of the present disclosure may include various blocks of any specifications.

[0012] The shoulders 11, sidewalls 12, and beads 13 are portions that form the side surfaces of the tire 1 and are provided on both sides in the width direction of the tire 1. The shoulders 11, sidewalls 12, and beads 13 extend radially inward from both ends of the tread 10 in the width direction. In this embodiment, the contact edge E of the tire 1 is defined as the boundary position between the tread 10 and the shoulders 11. The sidewalls 12 are rubber layers between the shoulders 11 and the beads 13, and are the part of the tire 1 that bends the most. The sidewalls 12 protect the carcass 15 and prevent its elongation. The tire 1 has annular ribs 22 on both sides in the width direction. The tips 22a of the annular ribs 22 may be defined as the boundary between the shoulders 11 and the sidewalls 12. In addition, the ground contact end E refers to both widthwise ends of the part that comes into contact with the ground when the tire 1 is mounted on a standard rim, the internal pressure is adjusted to the standard internal pressure, and a standard load is applied (for standard rims, etc., the same as described in Patent Publication No. 2020-131965).

[0013] The shoulders 11 are shoulder portions of the tire 1, and protrude outward in the width direction from both ends of the tread 10 in the width direction and extend radially inward. Like the tread 10, the shoulders 11 are provided in an annular shape along the circumferential direction. The sidewalls 12 extend radially inward from the shoulders 11 and are also provided in an annular shape along the circumferential direction. The sidewalls 12 include the portions that protrude most outward in the width direction of the tire 1, and are gently curved so as to be convex outward.

[0014] The bead 13 extends radially inward from the sidewall 12 and is formed in a ring shape along the circumferential direction. The bead 13 is a portion that is fixed to the rim of a wheel and constitutes the inner circumferential portion of the tire 1. The bead 13 is gently curved so as to convex toward the inside, and is located more inward than the sidewall 12 in the width direction.

[0015] The tire 1 includes a bead core 26 and a bead filler 27. The bead core 26 and the bead filler 27 are provided on both sides of the bead 13 in the width direction. The bead core 26 is a ring-shaped member made of bundled steel wires covered with rubber. The bead filler 27 is made of hard rubber and functions to increase the rigidity of the bead 13. The bead filler 27 is disposed radially outward of the bead core 26.

[0016] The tire 1 includes a carcass 15, which is a cord layer covered with rubber. The carcass 15 is made up of, for example, two carcass plies, and forms a tire framework that can withstand loads, impacts, air pressure, etc. The carcass 15 has a radial structure in which carcass cords are arranged in a direction perpendicular to the circumferential direction. The rubber layer that covers and protects the carcass 15 is generally made up of multiple rubber members such as tread rubber and sidewall rubber.

[0017] The tire 1 includes, for example, a belt 16 between the tread 10 and the carcass 15. The belt 16 is a reinforcing band stretched in the circumferential direction, and tightens the carcass 15 to increase the rigidity of the tread 10. The belt 16 is made up of, for example, two belt plies. Also, an inner liner 17, which is a rubber layer for maintaining air pressure, is attached to the inner peripheral surface of the carcass 15.

[0018] The carcass plies constituting the carcass 15 are arranged so as to be laid across a pair of bead cores 26. The carcass ply is laid across the bead cores 26 from the inside in the width direction and folded back towards the sidewall 12 so as to wrap around the bead cores 26 and the bead fillers 27. In the example shown in FIG. 1 , a ply end 15E, which is the end of the carcass ply, is located on the inside in the width direction of each sidewall 12. When the carcass 15 includes two carcass plies, the ply end of the other carcass ply is generally located in each bead 13. The sidewall 12 on the outer side of the vehicle has a side protector 60 that forms a protruding portion on the outside in the radial direction.

[0019] Fig. 2 is a perspective view of a portion of the tire 1 as viewed from the vehicle outer side in the width direction, and Fig. 3 is a perspective view of a portion of the tire 1 as viewed from the vehicle inner side in the width direction. As shown in Fig. 2, the shoulder blocks 40A are substantially identical and are arranged at substantially equal intervals in the circumferential direction around the entire circumference at substantially the same position in the width direction. Substantially identical lateral grooves 24b are provided between each pair of circumferentially adjacent shoulder blocks 40A. As shown in Fig. 3, the shoulder blocks 40B are substantially identical and are arranged at substantially equal intervals in the circumferential direction around the entire circumference at substantially the same position in the width direction. Substantially identical lateral grooves 24c are provided between each pair of circumferentially adjacent shoulder blocks 40B.

[0020] As shown in FIGS. 2 and 3 , in this embodiment, the tire 1 has multiple side protectors 60 only on the sidewall 12 on the vehicle outer side. As shown in FIG. 2 , each side protector 60 is a protrusion that protrudes outward in the width direction from the main body 55 of the sidewall 12. The multiple side protectors 60 are substantially identical and are arranged at substantially the same position in the width direction and at substantially equal intervals in the circumferential direction around the entire circumferential circumference. Each side protector 60 is located radially inward of the shoulder block 40A and radially outward in the sidewall 12. Each side protector 60 has a plate shape with substantially the same thickness. Each side protector 60 has multiple closed recesses 70 that are spaced apart in the circumferential direction and open outward in the width direction. Each closed recess 70 has an elongated shape and extends in a direction inclined at an acute angle in the radial direction.

[0021] The circumferential length of the side protector 60 is longer than the circumferential length of the shoulder block 40A. More specifically, in this embodiment, each side protector 60 has a circumferential length that is approximately equal to the sum of the circumferential lengths of the two shoulder blocks 40A and one lateral groove 24b.

[0022] 4 is an enlarged perspective view of the peripheral regions of two circumferentially adjacent side protectors 60 in FIG. 2. As shown in FIG. 4, the side protector 60 has two substantially identical blocking recesses 70 that are spaced apart in the circumferential direction and extend at an acute angle relative to the radial direction. The two blocking recesses 70 extend on the same circumferential side at an acute angle relative to the radial direction. The blocking recesses 70 have a step 71 at the peripheral edge of their bottoms that is shallower than a bottom 73 of the blocking recess 70. The step 71 exists around the entire peripheral edge of the bottom of the blocking recess 70. Each blocking recess 70 has an elongated opening 72, the edge of which is zigzag-shaped, and the opening 72 has a complex polygonal shape with seven or more sides. The opening 72 has an outer portion 74 and an inner portion 75 with a larger circumferential dimension on the radially outer and inner sides, and the outer portion 74 and the inner portion 75 are connected via a connecting portion 76 with a smaller circumferential dimension than the portions 74, 75. By giving the opening 72 such a complex shape, it is possible to improve traction performance.

[0023] 2 and 4, a recess 77 is present circumferentially between two adjacent side protectors 60. The circumferential length of the widthwise outer opening of the lateral groove 24b is approximately the same as the circumferential length of the radially outer portion 77a of the recess 77. In a plan view seen from outside the vehicle, approximately all of half of the lateral grooves 24b radially face the radially outer portion 77a of the recess 77. In this way, air that has passed through half of the lateral grooves 24b can easily flow into the recess 77, smoothing the flow of air that has passed through that half of the lateral grooves 24b and improving heat dissipation.

[0024] As shown in FIG. 4 , the side protector 60 has, on one circumferential side and a radially inward side, a first extending portion 81 that extends radially inward on one circumferential side, and a second extending portion 82 that extends radially inward on the other circumferential side and a radially inward side. A radially inner end 81a of the first extending portion 81 coincides with a radially inner end of the side protector 60. The first extending portion 81 and the second extending portion 82 face each other with a narrow circumferential gap. As a result, the recess 77 has, on the radially inner side, a narrow width portion 79 that has a circumferential length that is shorter than half the circumferential length of the radially outer portion 77a of the recess 77. A foreign object storage portion 84 that is likely to store foreign objects such as mud is located radially outward of the narrow width portion 79 of the recess 77.

[0025] In this way, by providing the first and second extension portions 81, 82 on both circumferential sides and the radially inner side of the side protector 60, the volume of the side protector 60 is increased, suppressing damage to the main body 55 of the sidewall 12 due to collision with a foreign object and improving protection performance. Furthermore, by allowing the tire 1 to receive a large reaction force from a foreign object that has entered the foreign object storage portion 84, the traction performance of the tire 1 is improved. Furthermore, by eliminating the first and second extension portions 81, 82 from being located on the radially outer side, a large air flow can be generated from the half of the lateral grooves 24b to the recess 77, thereby achieving excellent heat dissipation. Furthermore, a narrow groove 86 that communicates with the foreign object storage portion 84 is provided on the other circumferential side of the side protector 60. Providing the narrow groove 86 further improves the traction performance of the tire 1.

[0026] The outer side surface of the shoulder block 40A in the width direction is provided with a recess 88 that opens only to the outer side in the width direction. The outer edge 90 of the side protector 60 is formed in a zigzag shape, so that the outer edge 90 of the side protector 60 has multiple projections and recesses of different sizes. The projections 91 have sharply pointed tips 91a, and the recesses 92 have sharply pointed bottoms 92a. By providing the recess 88 on the outer side surface 95 of the shoulder block 40A in the width direction and providing the outer edge of the side protector 60 with multiple projections and recesses with sharply pointed tips 91a and bottoms 92b, the projections and recesses can more easily trap foreign objects such as mud, further improving the traction performance of the tire 1.

[0027] FIG. 5 is an enlarged plan view of the periphery of one side protector 60 of the tire 1 as viewed from the outside of the vehicle, and FIG. 6 is a cross-sectional view taken along line XX in FIG. 5. Note that the numerical values ​​in FIG. 6 are in millimeters. As shown in FIG. 6, the bottom 73 of the closed recess 70 is located outward in the width direction from the main body 55 of the sidewall 12, thereby improving the protection performance of the side protector 60 for the main body 55. In this embodiment, the thickness of the step 71 is 0.5 mm, the depth of the closed recess 70 is 1 mm, and the thickness of the step 71 is approximately half the depth of the closed recess 70. It is preferable that the thickness of the step 71 be 30% to 70% of the depth of the closed recess 70, since this makes it possible to improve both the protection performance of the side protector 60 and the traction performance of the closed recess 70.

[0028] [Required components and associated effects] As described above, the tire 1 includes a tread 10 and a plurality of side protectors 60 (protruding portions) that are located radially inward of shoulder blocks 40A (outermost blocks) that are provided on the tread 10 and located at the outermost positions on the vehicle, protrude outward in the width direction, and are spaced apart in the circumferential direction. The circumferential length of the side protectors 60 is longer than the circumferential length of the shoulder blocks 40A. The shoulder blocks 40A have a plurality of closed recesses 70 that are spaced apart in the circumferential direction and open outward in the width direction. A step 71 that is shallower than the bottom 73 of the closed recess 70 is provided on at least a portion of the peripheral edge of the bottom of the closed recess 70.

[0029] According to this configuration, the circumferential dimension of one side protector 60 is larger than the circumferential dimension of the shoulder block 40A. Furthermore, for the two or more closed recesses 70 provided in the side protector 60, a step 71 is provided on at least a portion of the peripheral edge of the bottom surface of each closed recess 70. Therefore, the circumferential dimension of the side protector 60 can be increased, and at least a portion of the peripheral edge of the bottom surface of each closed recess 70 provided in the side protector 60 can be protected by the step 71, effectively preventing foreign objects such as pebbles from colliding with the thin-walled bottom of the closed recess 70. This results in excellent protection performance. Furthermore, since the side protector 60 has two or more closed recesses 70, the traction performance of the side protector 60 can be excellent. Therefore, according to this configuration, two opposing effects that are in a trade-off relationship with each other, i.e., both protection performance and traction performance, can be improved.

[0030] [Preferable configuration to adopt, and the actions and effects associated with that configuration] The step 71 may be present around the entire periphery.

[0031] According to this configuration, it is possible to effectively prevent foreign matter from colliding with the thin bottom 73 of the blocking recess 70, thereby further improving the protection performance.

[0032] Additionally, the blocking recess 70 may extend in a generally radial direction or at an acute angle to the radial direction.

[0033] According to this configuration, the side protector 60 has multiple blocked recesses 70, and each blocked recess 70 extends in a direction that allows it to receive a large circumferential reaction force from mud that has entered therein, i.e., extends approximately parallel to the radial direction or in a direction that forms an acute angle with the radial direction, resulting in a synergistic effect that significantly improves the traction performance of the side protector 60.

[0034] Furthermore, the radial positions of the multiple side protectors 60 may all be substantially the same.

[0035] According to this configuration, it is possible to prevent the protection performance and traction performance from varying depending on the circumferential position, which would otherwise occur if a plurality of side protectors 60 were provided.

[0036] Alternatively, each side protector 60 may have two substantially identical blocking recesses 70 spaced apart in the circumferential direction and extending at an acute angle relative to the radial direction.

[0037] According to this configuration, it is easy to achieve a good balance between the protection performance and traction performance of the side protector 60, and both the protection performance and traction performance resulting from the provision of the side protector 60 can be made excellent.

[0038] [Variations] The present disclosure is not limited to the above-described embodiment and its variations. Various improvements and modifications are possible within the scope of the claims of the present application and their equivalents. For example, in the above-described embodiment, multiple side protectors 60 (protrusions) are provided only on the vehicle-outside side surface of the tire 1, and not on the vehicle-inside side surface of the tire 1. However, multiple protrusions may be provided on the vehicle-inside side surface of the tire in addition to the vehicle-outside side surface of the tire. This can improve the uniformity of weight and rigidity between the vehicle-outside side and the vehicle-inside side in the width direction, enable smooth tire rolling, and suppress uneven tire wear. Furthermore, although the blocking recess 70 is elongated and extends in a direction inclined toward the radial direction, the blocking recess 70 may also be elongated and extend approximately parallel to the radial direction.

[0039] Although the case where the blocking recess 70 has an annular step 71 on its periphery has been described, the blocking recess may have a non-annular step on a portion of the periphery of the bottom of the blocking recess. Furthermore, the case where each side protector 60 has two blocking recesses 70, and each blocking recess 70 has a step 71 on at least a portion of its periphery, has been described. However, each protruding portion (side protector) may have three or more blocking recesses, and each blocking recess may have a step on at least a portion of its periphery. For example, each protruding portion (side protector) may have three blocking recesses spaced apart in the circumferential direction, and each blocking recess may have a step on at least a portion of its periphery. Alternatively, each protruding portion (side protector) may have four blocking recesses arranged in a matrix of two rows and two columns, and each blocking recess may have a step on at least a portion of its periphery.

[0040] In addition, the case where the multiple side protectors 60 of the tire 1 are all substantially identical has been described. However, the multiple protrusions of the tire may include two or more different protrusions. In addition, the case where the multiple shoulder blocks 40A of the tire on the vehicle outer side are all substantially identical has been described. However, the multiple outermost blocks of the tire on the vehicle outer side may include two or more different outermost blocks. In addition, the case where the shoulder block 40A (outermost block) has a recess 88 on the outer side surface 95 in the width direction has been described, but the outermost block does not have to have a recess on the outer side surface in the width direction. [Explanation of symbols]

[0041] 1 tire, 10 tread, 10a ground contact surface, 11 shoulder, 12 sidewall, 13 bead, 15 carcass, 15E ply end, 16 belt, 17 inner liner, 22 rib, 22a rib tip, 24 groove, 24a main groove, 24b, 24c lateral groove, 26 bead core, 27 bead filler, 30 center rib, 40A, 40B shoulder block, 50A, 50B mediate block, 55 sidewall body, 60 side protector, 70 blocking recess, 71 step portion, opening of blocking recess, 73 bottom of blocking recess, 77 recess, 79 narrow width portion, 81 first extension portion, 82 second extension portion, 84 foreign object storage portion, 86 narrow groove, 88 recess, E ground edge.

Claims

1. Tread and a plurality of protruding portions that are provided on the tread, are located radially inward of an outermost block located at the outermost position of a vehicle, protrude outward in the width direction, and are spaced apart in the circumferential direction; Equipped with a circumferential length of each of the protrusions is longer than a circumferential length of the outermost block; The protruding portion has a plurality of closed recesses that are spaced apart in the circumferential direction and open outward in the width direction, a step having a depth shallower than that of the bottom of the blocking recess is provided on at least a part of a peripheral edge of the bottom of each of the blocking recesses, The pneumatic tire has a stepped portion that exists along the entire circumference of the circumferential edge portion.

2. The pneumatic tire according to claim 1 , wherein the closed recess extends substantially in the radial direction or at an acute angle relative to the radial direction.

3. The pneumatic tire according to claim 1 or 2, wherein the plurality of protrusions are all located at substantially the same radial positions.

4. The pneumatic tire according to claim 1 , wherein each of the protrusions has two substantially identical closed recesses that are spaced apart in the circumferential direction and extend at an acute angle with respect to the radial direction.

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