JP7805147B2 - pneumatic tires - Google Patents

Description

The present invention relates to a pneumatic tire.

Patent Document 1 describes a conventional pneumatic tire. 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 guards a portion of the main body from the outside in the width direction. The side protector prevents foreign objects, such as stones, that fly to the side of the tire when the vehicle is traveling on rough roads from striking and damaging the main body. The side protector has a recess that opens radially. This recess is provided to increase traction when the vehicle is traveling on muddy ground, thereby increasing driving force when the vehicle is traveling on rough roads.

Patent No. 6786927

In the above-mentioned pneumatic tire, if the area of the recesses 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 recesses is reduced in an attempt to improve protection performance of the tire sidewalls, traction performance will decrease. Therefore, the object of the present invention is to provide a pneumatic tire that easily achieves good both traction performance and protection performance.

The pneumatic tire of the present invention comprises a tread and a plurality of protruding portions spaced apart circumferentially, the protruding portions being located radially inward of the outermost block located at the outermost position of the vehicle and protruding outward in the width direction, the circumferential length of each protruding portion being longer than the circumferential length of the outermost block, the protruding portions having a plurality of closed recesses spaced apart circumferentially and opening outward in the width direction, and at least a portion of the peripheral edge of the bottom of each closed recess being provided with a step that is shallower than the bottom of the closed recess.

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 blocked recesses provided on the protrusion. This allows the circumferential dimension of the protrusion to be increased, and at least a portion of the peripheral edge of the bottom surface of each blocked recess provided on the protrusion is also protected by the step, effectively preventing pebbles and other foreign objects from colliding with the thin-walled bottom of the blocked recess. This provides excellent protection. Furthermore, because the protrusion has two or more blocked recesses, the traction performance of the protrusion can be improved. Therefore, the present invention makes it easy to achieve two opposing effects that are in a trade-off relationship with each other, namely, both protection and traction.

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. FIG. 2 is a perspective view of a portion of a pneumatic tire as viewed from the vehicle outer side in the width direction. FIG. 2 is a perspective view of a portion of a pneumatic tire as viewed from the vehicle inner side in the width direction. 3 is an enlarged perspective view of the peripheral regions of two circumferentially adjacent side protectors in FIG. 2. FIG. 1 is an enlarged plan view of the periphery of one side protector of a pneumatic tire as viewed from outside the vehicle. FIG. 6 is a cross-sectional view taken along line XX in FIG. 5.

Embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. It is anticipated that, where multiple embodiments or variations are included below, new embodiments may be constructed by appropriately combining their characteristic features. In the following examples, identical components are designated 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 and not required. 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.

Figure 1 is a half cross-sectional view, including the radial and width directions, of a pneumatic tire 1 according to one embodiment of the present invention. As shown in Figure 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 located 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 are 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 seeped between the road surface and the tire 1, thereby ensuring a contact area between the road surface and the tire 1.

The grooves 24 include, for example, main grooves 24a extending circumferentially and lateral grooves 24b, 24c extending in a direction intersecting the main grooves 24a (see Figures 2 and 3). The grooves 24 define blocks. In the example shown in Figure 1, the tread 10 has shoulder blocks 40A, 40B arranged circumferentially as blocks. The shoulder blocks 40A are located on the outer side of the vehicle (the right side in the width direction in Figure 1) and are arranged in a row with spaces between them in the circumferential direction. 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 Figure 1) and are arranged in a row with spaces between them in the circumferential direction.

The tread 10 further has a center rib 30 located in the widthwise center and multiple intermediate blocks 50A, 50B. The multiple intermediate blocks 50A are arranged in a row at intervals in the circumferential direction between the center rib 30 and the shoulder blocks 40A. The multiple intermediate 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 located 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.

The shoulders 11, sidewalls 12, and beads 13 form the side surfaces of the tire 1 and are provided on both widthwise sides of the tire 1. The shoulders 11, sidewalls 12, and beads 13 extend radially inward from both widthwise ends of the tread 10. In this embodiment, the contact edge E of the tire 1 is defined as the boundary 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 most flexible part of the tire 1. The sidewalls 12 protect the carcass 15 and prevent it from stretching. The tire 1 has annular ribs 22 on both widthwise sides. The tips 22a of the annular ribs 22 may be defined as the boundary between the shoulders 11 and the sidewalls 12. Note that the ground contact edges E refer 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 the standard load is applied (regarding standard rims, etc., the same as described in JP 2020-131965 A).

The shoulders 11 are shoulder portions of the tire 1, and extend outward in the width direction from both widthwise ends of the tread 10 and 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 portion that extends most outward in the width direction of the tire 1, and are gently curved so as to be convex outward.

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 fixed to the rim of the wheel and constitutes the inner periphery of the tire 1. The bead 13 is gently curved so that it convexly faces inward, and is located widthwise inward of the sidewall 12.

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 component 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 positioned radially outward of the bead core 26.

The tire 1 includes a carcass 15, which is a cord layer coated with rubber. The carcass 15 is composed 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 composed of multiple rubber components such as tread rubber and sidewall rubber.

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, tightly tightening the carcass 15 to increase the rigidity of the tread 10. The belt 16 is composed of, for example, two belt plies. An inner liner 17, which is a rubber layer that maintains air pressure, is attached to the inner surface of the carcass 15.

The carcass plies that make up the carcass 15 are positioned so as to span a pair of bead cores 26. The carcass plies are spanned from the inside in the width direction over the bead cores 26 and folded back toward the sidewall 12 to wrap around the bead cores 26 and bead fillers 27. In the example shown in Figure 1, the ply ends 15E, which are the ends of the carcass plies, are 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 side protectors 60 that form protrusions radially outward.

Figure 2 is a perspective view of a portion of the tire 1 viewed from the vehicle outer side in the width direction, and Figure 3 is a perspective view of a portion of the tire 1 viewed from the vehicle inner side in the width direction. As shown in Figure 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 Figure 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.

As shown in Figures 2 and 3, in this embodiment, the tire 1 has multiple side protectors 60 only on the sidewall 12 on the vehicle's outer side. As shown in Figure 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 direction. Each side protector 60 is located radially inward of the shoulder block 40A and radially outward on 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 circumferentially 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.

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.

Figure 4 is an enlarged perspective view of the peripheral regions of two circumferentially adjacent side protectors 60 in Figure 2. As shown in Figure 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. These two blocking recesses 70 extend on the same circumferential side relative to the radial direction at an acute angle. The blocking recesses 70 have a step 71 on the peripheral edge of their bottoms that is shallower than the bottom 73 of the blocking recess 70. The step 71 exists around the entire periphery of the peripheral edge of the bottom of the blocking recess 70. Each blocking recess 70 has an elongated opening 72, the edges of which are 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 larger circumferential dimensions 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. Giving the opening 72 such a complex shape can improve traction performance.

As shown in Figures 2 and 4, a recess 77 is present circumferentially between two adjacent side protectors 60. The circumferential length of the widthwise outer opening of each lateral groove 24b is approximately the same as the circumferential length of the radially outer portion 77a of each recess 77. In a plan view seen from outside the vehicle, approximately all of half of the multiple lateral grooves 24b are radially opposed to the radially outer portion 77a of each recess 77. In this way, air that has passed through half of the multiple 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.

As shown in FIG. 4 , the side protector 60 has a first extension portion 81 extending radially inward on one circumferential side and radially inward, and a second extension portion 82 extending radially inward on the other circumferential side and radially inward. The radially inner end 81a of the first extension portion 81 coincides with the radially inner end of the side protector 60. The first extension portion 81 and the second extension portion 82 face each other with a narrow circumferential gap. As a result, the recess 77 has a narrow width portion 79 on the radially inner side 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 in the recess 77.

In this way, by providing the first and second extensions 81, 82 on both circumferential sides and the radially inward side of the side protector 60, the volume of the side protector 60 is increased, preventing 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 withstand a large reaction force from a foreign object that has entered the foreign object storage compartment 84, the traction performance of the tire 1 is improved. Furthermore, by eliminating the first and second extensions 81, 82 from being located on the radially outward side, a large air flow is generated that flows from the above-mentioned half of the lateral grooves 24b to the recess 77, achieving excellent heat dissipation. Furthermore, a narrow groove 86 that communicates with the foreign object storage compartment 84 is provided on the other circumferential side of the side protector 60. The provision of the narrow groove 86 further improves the traction performance of the tire 1.

The outer widthwise side of the shoulder block 40A is provided with a recess 88 that opens only to the outer widthwise side. The outer edge 90 of the side protector 60 is zigzag, creating multiple protrusions and recesses of different sizes on the outer edge 90 of the side protector 60. The protrusions 91 have sharply pointed tips 91a, while the recesses 92 have sharply pointed bottoms 92a. By providing the recess 88 on the outer widthwise side 95 of the shoulder block 40A and providing the outer edge of the side protector 60 with multiple protrusions and recesses with sharply pointed tips 91a and bottoms 92b, the protrusions and recesses make it easier for mud and other foreign objects to be caught by the recesses and recesses, further improving the traction performance of the tire 1.

Figure 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 Figure 6 is a cross-sectional view taken along line X-X in Figure 5. Note that the numerical values in Figure 6 are in millimeters. As shown in Figure 6, the bottom 73 of the blocking recess 70 is located widthwise outward of the main body 55 of the sidewall 12, thereby enhancing the side protector 60's ability to protect the main body 55. In this embodiment, the thickness of the step 71 is 0.5 mm, the depth of the blocking recess 70 is 1 mm, and the thickness of the step 71 is approximately half the depth of the blocking recess 70. It is preferable for the thickness of the step 71 to be between 30% and 70% of the depth of the blocking recess 70, as this will ensure both excellent protection by the side protector 60 and excellent traction performance by the blocking recess 70.

[Essential 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. At least a portion of the peripheral edge of the bottom of the closed recesses 70 is provided with a step 71 that is shallower than the bottom 73 of the closed recesses 70.

With 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 blocked 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 blocked recess 70. This allows the circumferential dimension of the side protector 60 to be increased, and the step 71 also protects at least a portion of the peripheral edge of the bottom surface of each blocked recess 70 provided in the side protector 60, effectively preventing pebbles and other foreign objects from colliding with the thin-walled bottom of the blocked recess 70. This results in excellent protection performance. Furthermore, because the side protector 60 has two or more blocked recesses 70, the traction performance of the side protector 60 can be improved. Therefore, with this configuration, two opposing effects that are in a trade-off relationship with each other, namely, protection performance and traction performance, can both be improved.

[Preferable configurations to be adopted and the associated effects]
The step 71 may be present around the entire periphery.

This configuration effectively prevents foreign objects from colliding with the thin-walled bottom 73 of the blocking recess 70, further improving protection performance.

The blocking recess 70 may also extend in a generally radial direction or at an acute angle to the radial direction.

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

Furthermore, the radial positions of multiple side protectors 60 may all be approximately the same.

This configuration prevents the protection and traction performance from varying with circumferential position due to the provision of multiple side protectors 60.

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.

This configuration makes it easier to achieve a good balance between the protection and traction performance of the side protector 60, and the provision of the side protector 60 can result in excellent protection and traction performance.

[Modification]
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, a case has been described in which multiple side protectors 60 (protrusions) are provided only on the vehicle-outer side surface of the tire 1, and not on the vehicle-inner side surface of the tire 1. However, multiple protrusions may be provided on the vehicle-inner side surface of the tire in addition to the vehicle-outer side surface of the tire. This can improve the uniformity of weight and rigidity between the vehicle-outer side surface in the width direction and the vehicle-inner side surface 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.

In addition, while the blocking recess 70 has been described as having an annular step 71 on its periphery, the blocking recess may also have a non-annular step partially on the periphery of the bottom of the blocking recess. Also, in the above description, 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. 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. Or, each protruding portion (side protector) may have four blocking recesses arranged in a two-row, two-column matrix, and each blocking recess may have a step on at least a portion of its periphery.

Also, in the above description, the multiple side protectors 60 of the tire 1 are all substantially identical. However, the multiple protrusions of the tire may include two or more different protrusions. Also, in the above description, the multiple shoulder blocks 40A of the tire on the vehicle outer side are all substantially identical. However, the multiple outermost blocks of the tire on the vehicle outer side may include two or more different outermost blocks. Also, in the above description, the shoulder blocks 40A (outermost blocks) have recesses 88 on their outer side surfaces 95 in the width direction, but the outermost blocks do not need to have recesses on their outer side surfaces in the width direction.

REFERENCE SIGNS LIST 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 Depression, 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 (4)

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