Pneumatic tire

Abstract

To provide a pneumatic tire capable of suppressing occurrence of crack.SOLUTION: A pneumatic tire includes a tread and side walls. The side walls include: a plurality of first blocks which has an outer diameter side basic surface disposed outside in a tire radial direction of a maximum width position where the width of the side walls in a tire axial direction becomes maximum and hexagonal first surfaces arranged at intervals outside in the tire axial direction from the outer diameter side basic surface of tire side surfaces, and is arranged along a tire circumferential direction; and a plurality of second blocks which has polygonal second surfaces arranged outside in the tire axial direction at intervals from the outer diameter side basic surface, are arranged inside or outside in the tire radial direction with respect to the plurality of first blocks along the tire circumferential direction, and arranged in a honeycomb shape in the plurality of first blocks. In each of the first blocks, at least one first narrow groove recessed inside from the first surface in the tire axial direction is arranged.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to pneumatic tires. [Background technology]

[0002] Patent Document 1 discloses a pneumatic tire in which a plurality of hexagonal blocks are defined and formed by providing a plurality of grooves in the sidewall. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-20672 A Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, since blocks are formed in the sidewall, heat is likely to accumulate in the sidewall, and the heat accumulated in the sidewall reduces the durability of the sidewall, which may cause cracks.

[0005] An object of the present disclosure is to provide a pneumatic tire that can suppress the occurrence of cracks. [Means for solving the problem]

[0006] One aspect of the present disclosure is Tread and a sidewall extending radially inward from an axial end of the tread; Equipped with The sidewall is An outer diameter side basic surface arranged on the tire radial direction outer side of a maximum width position where the width of the sidewall in the tire axial direction is maximum, among the tire side surfaces; a plurality of first blocks each having a hexagonal first surface arranged at intervals from the outer diameter side basic surface outward in the tire axial direction and arranged side by side in the tire circumferential direction; a plurality of second blocks each having a polygonal second surface disposed at an interval from the outer diameter side basic surface to the outside in the tire axial direction, the second blocks being disposed side by side in the tire circumferential direction on the inside or outside of the plurality of first blocks in the tire radial direction, and being disposed in a honeycomb pattern on the plurality of first blocks; Equipped with A pneumatic tire is provided, in which each first block has at least one first narrow groove disposed therein, recessed from the first surface inward in the tire axial direction.

[0007] According to this configuration, since at least one first narrow groove is disposed in each first block, air flows through at least one first narrow groove, improving the heat dissipation of the sidewall, thereby preventing the durability of the sidewall from being reduced due to heat generated in the sidewall, leading to cracks.

[0008] In addition, since at least one first fine groove is disposed in each first block, the rigidity of the sidewall can be prevented from increasing excessively compared to a case in which no first fine groove is disposed in each first block, and as a result, shocks received from the road surface can be absorbed by the sidewall flexing, improving ride comfort.

[0009] In addition, a plurality of second blocks arranged in a honeycomb pattern are disposed on the inner or outer side of the plurality of first blocks in the tire radial direction. With this configuration, when a load acts on the pneumatic tire, the first blocks and the second blocks come into contact with each other, so that the load acting on the sidewall is distributed to the first blocks and the second blocks. As a result, it is possible to suppress the occurrence of cracks or wrinkles on the outer diameter side basic surface of the sidewall. Effect of the Invention

[0010] According to the present disclosure, a pneumatic tire capable of suppressing the occurrence of cracks can be provided. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a perspective view of a pneumatic tire including a meridian section of the pneumatic tire according to one embodiment of the present disclosure. [Diagram 2] FIG. 2 is a side view of the outer diameter side basic surface of the pneumatic tire shown in FIG. [Diagram 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. 4 is a side view of the outer diameter side basic surface of the pneumatic tire shown in FIG. 1 when a normal load is applied. [Diagram 5] FIG. 2 is an enlarged cross-sectional view of region A in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, a pneumatic tire according to an embodiment of the present disclosure will be described with reference to the accompanying drawings.

[0013] Fig. 1 is a perspective view of a pneumatic tire 1 (hereinafter, sometimes simply referred to as a tire 1) according to an embodiment of the present disclosure, including a meridian cross section of the tire 1. Fig. 1 shows only one side in the tire axial direction with respect to the tire equator CL. In the following description, in the tire axial direction, a direction toward the tire equator CL may be referred to as an inner side, and a direction away from the tire equator CL may be referred to as an outer side.

[0014] [Tire structure] The tire 1 of this embodiment is a heavy-duty tire made of rubber. Heavy-duty tires are tires described in "Chapter C: for trucks and buses" or "Chapter D: for construction vehicles" of the JATMA (Japan Automobile Tire Manufacturers Association) standard. The tire 1 includes a tread 10 extending in the tire axial direction, a pair of sidewalls 20 each extending radially inward from both ends of the tread 10 in the tire axial direction, and a pair of beads 30 disposed at the inner ends of the pair of sidewalls 20 in the tire radial direction.

[0015] The tread 10 extends in the circumferential direction of the tire so as to extend cylindrically around the axis of the tire 1. The tread 10 is disposed at the outer end in the radial direction of the tire, and has a tread surface 11 which is the contact surface that comes into contact with the ground when the tire 1 rolls.

[0016] The bead 30 includes a bead core 31 disposed on the inner side in the tire radial direction, and a bead filler 32 disposed in contact with the bead core 31. The bead core 31 includes a number of steel wires bundled into a ring shape. The bead filler 32 is ring-shaped and surrounds the bead core 31, and is made of a rubber harder than the rubber constituting the tread 10 and the sidewall 20. The bead filler 32 extends from the bead core 31 toward the outer side in the tire radial direction in a direction inclined outward in the tire axial direction.

[0017] The tire 1 includes an inner liner 40 extending from an inner end of the tread 10 in the tire radial direction, an inner end of the sidewall 20 in the tire axial direction, and an inner end of the bead 30 in the tire axial direction. A carcass 41 is laminated on the outer side of the inner liner 40 and is toroidally stretched between the pair of beads 30.

[0018] Between the tread surface 11 of the tread 10 and the carcass 41, a belt layer 42 extending in the circumferential direction of the tire is disposed.

[0019] The belt layer 42 has four belt plies 42a to 42d laminated in the tire radial direction. Specifically, the belt layer 42 has a first belt ply 42a disposed on the innermost side in the tire radial direction, a second belt ply 42b disposed on the outer side in the tire radial direction of the first belt ply 42a, a third belt ply 42c disposed on the outer side in the tire radial direction of the second belt ply 42b, and a fourth belt ply 42d disposed on the outer side in the tire radial direction of the third belt ply 42c. In this embodiment, the belt layer 42 has four belt plies 42a to 42d, but may have a different number of belt plies, for example, two or three belt plies.

[0020] In the tread 10 of this embodiment, three circumferential grooves 12 (only two are shown in FIG. 1 ) extending in the tire circumferential direction are arranged at intervals in the tire axial direction. In this embodiment, of the three circumferential grooves 12, the circumferential groove 12 arranged on the tire equator CL may be referred to as an inner circumferential groove 12A, and each of the two circumferential grooves 12 arranged axially outboard of the inner circumferential groove 12A may be referred to as an outer circumferential groove 12B.

[0021] In the tread 10, a plurality of lands 13 extending in the tire circumferential direction are defined by an inner circumferential groove 12A and an outer circumferential groove 12B. Each land 13 is a rubber layer that extends from the inner liner 40 to the outer end of the tread 10 in a direction perpendicular to the surface of the inner liner 40. In FIG. 1, two rows of lands 13 are defined, but the number of circumferential grooves 12 and the number of lands 13 can be changed as necessary.

[0022] In the following description, among the multiple lands 13, the land 13 arranged between the inner circumferential groove 12A and the outer circumferential groove 12B may be referred to as a quarter land 13A. Also, among the multiple lands 13, the land 13 arranged axially outboard of the outer circumferential groove 12B may be referred to as a shoulder land 13B.

[0023] A parting line PL extending in the tire circumferential direction is disposed between the tread 10 and the sidewall 20. The parting line PL is a parting line between a tread mold for molding the tread 10 and a side mold for molding the sidewall 20 in a vulcanization process for molding the tire 1. In this embodiment, the parting line PL is an inner end of the shoulder land 13B in the tire radial direction on the side surface of the tire 1, and is a boundary between the tread 10 and the sidewall 20.

[0024] The sidewall 20 has a basic surface 21 that does not include partial recesses such as grooves and partial protrusions on the outer surface of the sidewall 20. The basic surface 21 includes an outer basic surface 21a arranged radially outward from a maximum tire width position where the tire axial width of the sidewall 20 (the axial distance between the basic surface 21 and the tire equator CL) is maximum, and an inner basic surface 21b arranged radially inward from the maximum tire width position of the basic surface 21. In detail, the outer basic surface 21a is arranged radially outward from a virtual line VL extending in the tire circumferential direction so as to pass through the maximum tire width position, and the inner basic surface 21b is arranged radially inward from the virtual line VL. The outer basic surface 21a is arranged between the parting line PL and the virtual line VL.

[0025] The sidewall 20 is provided with a honeycomb-shaped block group 22 (hereinafter, may be simply referred to as a block group 22) disposed on an outer diameter side basic surface 21a and protruding outward in the tire axial direction from the outer diameter side basic surface 21a. In this specification, the term "honeycomb-shaped" is used not only to mean a honeycomb structure in the narrow sense consisting of only a plurality of hexagonal columns, but also to a honeycomb structure in the broad sense consisting of a plurality of polygonal columns including not only hexagonal columns but also other polygonal columns such as pentagonal columns.

[0026] FIG. 2 is a side view of the outer diameter side basic surface 21a of the tire 1 of FIG.

[0027] 2, block group 22 includes a plurality of hexagonal blocks 50, a plurality of pentagonal blocks 60A arranged radially outward from the plurality of hexagonal blocks 50, and a plurality of pentagonal blocks 60B arranged radially inward from the plurality of hexagonal blocks 50. In the following description, when there is no need to particularly distinguish between the plurality of pentagonal blocks 60A and the plurality of pentagonal blocks 60B, one of the plurality of pentagonal blocks 60A and the plurality of pentagonal blocks 60B may be simply referred to as a pentagonal block 60.

[0028] Gaps 22a are arranged between the circumferentially adjacent hexagonal blocks 50, between the circumferentially adjacent pentagonal blocks 60, and between the adjacent hexagonal blocks 50 and pentagonal blocks 60. The gaps 22a spread in a honeycomb shape on the outer diameter side basic surface 21a. The width W1 of the gaps 22a is 0.2 mm or more and 0.5 mm or less.

[0029] The multiple hexagonal blocks 50 are disposed midway between the parting line PL and the virtual line VL. The multiple hexagonal blocks 50 are disposed side by side in the tire circumferential direction. Each hexagonal block 50 has a hexagonal column shape protruding from the outer diameter side basic surface 21a to the outside in the tire axial direction. Each hexagonal block 50 has a hexagonal upper surface 51 disposed at an interval from the outer diameter side basic surface 21a to the outside in the tire axial direction. The hexagonal block 50 of this embodiment is an example of a first block according to the present disclosure. The upper surface 51 of the hexagonal block 50 of this embodiment is an example of a first surface according to the present disclosure.

[0030] The upper surface 51 includes six vertices 51a-51f and six sides 51g-51l each connecting two adjacent vertices among the six vertices 51a-51f. In this embodiment, the sides 51h and 51k extend in the tire radial direction and are spaced apart in the tire circumferential direction. In other words, the sides 51h and 51k are opposed to each other in the tire circumferential direction. The sides 51h and 51k in this embodiment are an example of a pair of opposing sides according to the present disclosure.

[0031] Each hexagonal block 50 has four fine grooves 52A-52D recessed from an upper surface 51 inward in the tire axial direction. The upper surface 51 is divided into six triangles T1-T6 by the fine grooves 52A-52D. In the following description, when there is no need to particularly distinguish between the four fine grooves 52A-52D, one of the four fine grooves 52A-52D may be simply referred to as a fine groove 52. The fine grooves 52A-52D of this embodiment are an example of a first fine groove according to the present disclosure.

[0032] The narrow groove 52A is disposed on a diagonal line connecting the outer end of the side 51h in the tire radial direction, ie, the vertex 51b, and the inner end of the side 51k in the tire radial direction, ie, the vertex 51e.

[0033] Thin groove 52B is disposed on a diagonal line connecting the inner end of side 51h in the tire radial direction, i.e., vertex 51c, and the outer end of side 51k in the tire radial direction, i.e., vertex 51f. Thin groove 52B intersects with thin groove 52A near the centroid of upper surface 51.

[0034] The narrow groove 52C is disposed on a diagonal line connecting the outer end of the side 51h in the tire radial direction, i.e., the vertex 51b, and the outer end of the side 51k in the tire radial direction, i.e., the vertex 51f. The narrow groove 52C extends in the tire circumferential direction.

[0035] The narrow groove 52D is disposed on a diagonal line connecting the inner end of the side 51h in the tire radial direction, i.e., the vertex 51c, and the inner end of the side 51k in the tire radial direction, i.e., the vertex 51e. The narrow groove 52D extends in the tire circumferential direction.

[0036] In this embodiment, no fine groove is arranged on the diagonal line connecting vertices 51a and 51d of upper surface 51. In other words, in this embodiment, no fine groove extending in the tire radial direction is arranged on upper surface 51.

[0037] In each hexagonal block 50, a hole 53 extending inward in the tire radial direction from the upper surface 51 is disposed at an intersection of the thin groove 52A and the thin groove 52B. In this embodiment, the hole 53 has a circular shape in a side view.

[0038] The pentagonal blocks 60A are arranged in a row in the tire circumferential direction. The pentagonal blocks 60B are arranged in a row in the tire circumferential direction. The pentagonal blocks 60 are arranged in a honeycomb shape in the hexagonal blocks 50. Each pentagonal block 60 has a pentagonal column shape protruding from the outer diameter side basic surface 21a to the outside in the tire axial direction. Each pentagonal block 60 has a pentagonal upper surface 61 arranged at an interval from the outer diameter side basic surface 21a to the outside in the tire axial direction. The pentagonal block 60 of this embodiment is an example of a second block according to the present disclosure. The upper surface 61 of the pentagonal block 60 of this embodiment is an example of a second surface according to the present disclosure.

[0039] The upper surface 61 includes five vertices 61a-61e and six sides 61f-61j each connecting two adjacent vertices of the five vertices 61a-61e. In this embodiment, the sides 61g and 61i extend in the tire radial direction and are spaced apart in the tire circumferential direction. The sides 61g and 61i are opposed to each other in the tire circumferential direction. The side 61f extends parallel to the opposing side of the sides 51g-51l constituting the upper surfaces 51 of the adjacent hexagonal blocks 50. The side 61j extends parallel to the opposing side of the sides 51g-51l constituting the upper surfaces 51 of the adjacent hexagonal blocks 50.

[0040] Each pentagonal block 60 has one narrow groove 62 recessed from the upper surface 61 toward the inside in the tire axial direction. The narrow groove 62 of the pentagonal block 60A is disposed on a diagonal line connecting the inner ends in the tire radial direction of the sides 61g, 61i that are disposed opposite each other in the circumferential direction, that is, the vertices 61b and 61e. Similarly, the narrow groove of the pentagonal block 60B is disposed on a diagonal line connecting the outer ends in the tire radial direction of the sides 61g, 61i that are disposed opposite each other in the circumferential direction, that is, the vertices 61b and 61e. The narrow groove 62 of this embodiment is an example of a second narrow groove of the present disclosure.

[0041] The upper surface 61 is divided into one triangle T7 and one rectangle S by the fine grooves 62. The triangle T7 of the pentagonal block 60A is disposed between two hexagonal blocks 50 adjacent to each other in the tire circumferential direction.

[0042] In this specification, the dimensions, angles, and positions of each member are measured with the tire 1 mounted on a standard rim, inflated to the standard internal pressure, and in an unloaded state.

[0043] A "genuine rim" is a rim that is determined for each tire by the standard system that includes the standard on which the tire is based. For example, in the case of JATMA, it is called a "standard rim," and in the cases of TRA and ETRTO, it is called a "Measuring Rim."

[0044] "Normal internal pressure" refers to the air pressure set for each tire by each standard in the standard system on which the tire is based. For JATMA, it is the "maximum air pressure." For TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES." For ETRTO, it is the "INFLATION PRESSURE."

[0045] A tire radial dimension L1 of each hexagonal block 50 is larger than a tire circumferential dimension L2. Specifically, the tire radial dimension L1 of each hexagonal block 50 is set to be 2.0 times the tire circumferential dimension L2. In this embodiment, the tire radial dimension L1 of each hexagonal block 50 is 2.0 times the tire circumferential dimension L2, but may be a different size as long as it is 0.5 to 2.0 times the tire circumferential dimension L2.

[0046] FIG. 3 is a cross-sectional view taken along line III-III in FIG.

[0047] Referring to FIG. 3, the width W2 of the narrow groove 52 is 0.5 mm to 2.0 mm. In this embodiment, the width W2 of the narrow groove 52 is wider than the width W1 of the gap 22a. The depth D1 of the narrow groove 52 is 0.5 to 1.0 times the height H1 from the outer diameter side basic surface 21a of the hexagonal block 50. In this embodiment, the depth D1 of the narrow groove 52 is 0.5 times the height H1. The height H1 is 2.5 to 4.0 times the width W1 of the gap 22a. The height H1 may be 0.5 mm to 2.0 mm.

[0048] The diameter φ of the hole 53 is 2.0 mm or more and 4.0 mm or less. In this embodiment, the diameter φ of the hole 53 is larger than the width W2 of the narrow groove 52. The depth D2 of the hole 53 is 0.5 times or more and 1.0 times or less the height H1 from the outer diameter side basic surface 21a of the hexagonal block 50. In this embodiment, the depth D2 of the hole 53 is 1.0 times the height H1 from the outer diameter side basic surface 21a of the hexagonal block 50. The depth D2 of the hole 53 in this embodiment is deeper than the depth D1 of the narrow groove 52. In other words, the hole 53 in this embodiment extends axially inward from the bottom surface of the narrow groove 52.

[0049] The width W3 of the narrow groove 62 is 0.5 mm to 2.0 mm. In this embodiment, the width W3 of the narrow groove 62 is wider than the width W1 of the gap 22a. The depth D3 of the narrow groove 62 is 0.5 to 1.0 times the height H2 from the outer diameter side basic surface 21a of the pentagonal block 60. In this embodiment, the depth D3 of the narrow groove 62 is 0.5 times the height H2. The height H2 is 2.5 to 4.0 times the width W1 of the gap 22a. The height H2 may be 0.5 mm to 2.0 mm.

[0050] When the tire 1 is subjected to a radial load, the hexagonal blocks 50 and the pentagonal blocks 60 are compressed in the tire radial direction so that the sidewall 20, particularly the outer diameter side basic surface 21a, curves toward the inside in the tire axial direction, thereby approaching each other.

[0051] FIG. 4 is a side view of the outer diameter side basic surface 21a when a normal load is applied.

[0052] "Normal load" refers to the load that is determined for each tire by each standard in the system of standards, including the standard on which the tire is based. For JATMA, it is "maximum load capacity." For TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES." For ETRTO, it is "LOAD CAPACITY."

[0053] 4, when a normal load or a load greater than the normal load is applied in the tire radial direction, the hexagonal blocks 50 and the pentagonal blocks 60 come into contact with each other while inclining toward each other in the tire radial direction. Therefore, when at least a normal load is applied in the tire radial direction, the hexagonal blocks 50 and the pentagonal blocks 60 come into contact with each other, dispersing the load applied to the tire sidewalls, thereby suppressing the occurrence of cracks or wrinkles in the outer diameter side basic surface 21a.

[0054] Fig. 5 is an enlarged cross-sectional view of region A in Fig. 1. Referring to Fig. 5, corners 23A, 23B located between each pentagonal block 60 and a portion of the tire side surface that is located on the opposite side of the hexagonal block 50 from each pentagonal block 60 are arcs having a radius of 3 mm or more and 15 mm or less. Specifically, corners 23A located between each pentagonal block 60A and the side surface of shoulder land 13B are arcs having a radius of 3 mm or more and 15 mm or less. Corners 23B located between each pentagonal block 60B and inner diameter side basic surface 21b are arcs having a radius of 3 mm or more and 15 mm or less.

[0055] In a region R of the tire sidewall located between 1 mm and 20 mm inward in the tire radial direction from an end 10a of the tread 10 in the tire axial direction, a recess 70 is disposed that is recessed from the tire sidewall toward the tire axially inward. In the cross section shown in Fig. 5, the recess 70 is composed of two arcs 71, 72 having a center on the outer side in the tire axial direction with respect to the tire sidewall. Specifically, the recess 70 is composed of an outer diameter side arc 71 that is located on the outer side in the tire radial direction of the two arcs 71, 72, and an outer diameter side arc 72 that is located on the inner side in the tire radial direction of the two arcs 71, 72.

[0056] The radius of the outer diameter side arc 71 is 3 mm or more and 15 mm or less. Similarly, the radius of the inner diameter side arc 72 is 3 mm or more and 15 mm or less. In this embodiment, the radius of the outer diameter side arc 71 is larger than the radius of the inner diameter side arc 72.

[0057] A distance Di between the depression 70 and an end of the belt layer 42 is 12 mm or more. In this embodiment, the distance Di is the distance between the depression 70 and an end in the tire axial direction of the second belt ply 42b, which is the widest among the belt plies 42a to 42d constituting the belt layer 42.

[0058] [effect] The tire 1 according to the present embodiment provides the following advantages.

[0059] According to the tire 1 according to the present embodiment, the narrow grooves 52 are arranged in each hexagonal block 50, and air flows through the narrow grooves 52, thereby improving the heat dissipation performance of the sidewall 20. As a result, it is possible to suppress the durability of the sidewall 20 from being reduced due to heat generated in the sidewall 20, leading to the occurrence of cracks.

[0060] According to the tire 1 according to the present embodiment, the fine grooves 52 are arranged in each hexagonal block 50, and therefore it is possible to prevent the rigidity of the sidewall 20 from becoming excessively high, compared to a case in which the fine grooves 52 are not arranged in each hexagonal block 50. As a result, the sidewall 20 can bend and absorb impacts from the road surface, thereby improving ride comfort.

[0061] In the tire 1 according to the present embodiment, a plurality of pentagonal blocks 60 arranged in a honeycomb pattern are arranged on the inner and outer sides of the plurality of hexagonal blocks 50 in the tire radial direction. With this configuration, when a load acts on the tire 1, the hexagonal blocks 50 and the pentagonal blocks 60 come into contact with each other, so that the load acting on the sidewall 20 is distributed to the hexagonal blocks 50 and the pentagonal blocks 60. As a result, it is possible to suppress the occurrence of cracks or wrinkles on the outer diameter side basic surface 21a of the sidewall 20.

[0062] In the tire 1 according to this embodiment, the upper surface 51 is divided into a plurality of triangles by the four narrow grooves 52, so that the load acting on the hexagonal blocks 50 when the tire 1 is loaded is further dispersed within the hexagonal blocks 50. As a result, the occurrence of cracks or wrinkles on the outer diameter side basic surface 21a of the sidewall 20 can be suppressed.

[0063] According to the tire 1 according to the present embodiment, holes 53 extending from the top surface 51 to the inside in the tire axial direction from the bottom surfaces of the two narrow grooves 52 at the intersections of two intersecting narrow grooves 52 out of the four narrow grooves 52 are disposed in each hexagonal block 50. As a result, air flowing through the two narrow grooves 52 flows through the holes 53, thereby improving the heat dissipation performance of the sidewall 20 and suppressing the occurrence of cracks due to heat generated in the sidewall 20.

[0064] According to the tire 1 according to the present embodiment, the narrow grooves 62 are arranged in each pentagonal block 60, and air flows through the narrow grooves 62, thereby improving the heat dissipation performance of the sidewall 20. As a result, the occurrence of cracks due to heat generated in the sidewall 20 can be suppressed.

[0065] In the tire 1 according to this embodiment, the corners 23A, 23B between each pentagonal block 60 and a portion of the tire side surface that is located on the opposite side of the hexagonal blocks 50 from each pentagonal block 60 are arcs having a radius of 3 mm or more and 15 mm or less. This makes it possible to suppress stress concentration at the base of each pentagonal block 60. As a result, it is possible to suppress cracks from occurring at the base of each pentagonal block 60.

[0066] According to the tire 1 according to this embodiment, in an area of ​​the tire sidewall located between 1 mm and 20 mm radially inward from the end 10a of the tread 10 in the tire axial direction, recesses 70 recessed from the tire sidewall toward the tire axially inward are arranged, thereby reducing the rigidity at the ground contact end of the tread 10. As a result, the ground contact at the ground contact end of the tread 10 can be improved, and the ground contact pressure at the ground contact end of the tread 10 can be reduced.

[0067] According to the tire 1 of this embodiment, the distance between the end of the belt layer 42 in the tire axial direction and the recess 70 is 12 mm or more, so that the occurrence of failures such as separation at the end of the belt layer 42 in the tire axial direction can be suppressed.

[0068] [Variations] The pneumatic tire according to the present disclosure is not limited to the configuration of the above-described embodiment, and various modifications are possible.

[0069] In the above embodiment, four fine grooves 52 are arranged in each hexagonal block 50, but it is sufficient that at least one fine groove 52 is arranged, and five or more fine grooves 52 may be arranged. Also, in the above embodiment, the plurality of fine grooves 52 divide the upper surface 51 of the hexagonal block 50 into a plurality of triangles T1 to T6, but the arrangement of the plurality of fine grooves 52 is not limited to this.

[0070] In the above embodiment, one fine groove 62 is arranged in each pentagonal block 60, but it is sufficient that at least one fine groove 62 is arranged, and two or more fine grooves 52 may be arranged. Also, in the above embodiment, one fine groove 62 divides the upper surface 61 of the pentagonal block 60 into a triangle T7 and a quadrangle S, but the arrangement of the fine grooves 62 is not limited to this.

[0071] In the above embodiment, the pentagonal block 60 has been described as an example of the second block according to the present disclosure, but the second block according to the present disclosure is not limited to the pentagonal block 60. The second block according to the present disclosure may be any block having a polygonal prism shape.

[0072] [Note] The pneumatic tire according to the present disclosure provides the following aspects.

[0073] [Aspect 1] The pneumatic tire according to the present disclosure includes: Tread and a sidewall extending radially inward from an axial end of the tread; Equipped with The sidewall is An outer diameter side basic surface arranged on the tire radial direction outer side of a maximum width position where the width of the sidewall in the tire axial direction is maximum, among the tire side surfaces; a plurality of first blocks each having a hexagonal first surface arranged at intervals from the outer diameter side basic surface outward in the tire axial direction and arranged side by side in the tire circumferential direction; a plurality of second blocks each having a polygonal second surface disposed at an interval from the outer diameter side basic surface to the outside in the tire axial direction, the second blocks being disposed side by side in the tire circumferential direction on the inside or outside of the plurality of first blocks in the tire radial direction, and being disposed in a honeycomb pattern on the plurality of first blocks; Equipped with A pneumatic tire is provided, in which each first block has at least one first narrow groove disposed therein, recessed from the first surface inward in the tire axial direction.

[0074] [Aspect 2] The pneumatic tire according to the present disclosure includes: the at least one first narrow groove includes a plurality of first narrow grooves, The pneumatic tire according to aspect 1 is provided, wherein the plurality of first narrow grooves are arranged so as to divide the first surface into a plurality of triangles.

[0075] [Aspect 3] The pneumatic tire according to the present disclosure includes: The first surface has a pair of opposite sides extending in a tire radial direction and spaced apart in a tire circumferential direction, The present invention provides a pneumatic tire according to aspect 2, wherein the plurality of first narrow grooves are composed of four first narrow grooves arranged on four diagonal lines respectively connecting the radially inner end and the radially outer end of each of the pair of opposite sides.

[0076] [Aspect 4] The pneumatic tire according to the present disclosure includes: A pneumatic tire according to aspect 3 is provided, wherein each first block has a hole disposed at an intersection of two intersecting first narrow grooves among the four first narrow grooves, the hole extending from the first surface to an inner side in the tire axial direction from bottom surfaces of the two first narrow grooves.

[0077] [Aspect 5] The pneumatic tire according to the present disclosure includes: A pneumatic tire according to any one of Aspects 1 to 4 is provided, wherein each second block has at least one second narrow groove recessed from the second surface toward the inside in the tire axial direction.

[0078] [Aspect 6] The pneumatic tire according to the present disclosure includes: Aspects 6. The pneumatic tire according to any one of aspects 1 to 5, wherein a corner between each second block and a portion of the tire sidewall opposite the plurality of first blocks with respect to each second block is an arc having a radius of 3 mm or more and 15 mm or less.

[0079] [Aspect 7] The pneumatic tire according to the present disclosure includes: In a region of the tire sidewall located between 1 mm and 20 mm inward in the tire radial direction from an end of the tread in the tire axial direction, a recess is disposed inward in the tire axial direction from the tire sidewall, A pneumatic tire according to any one of aspects 1 to 6 is provided, wherein the depression is formed of two circular arcs having centers on the outer side in the tire axial direction with respect to the tire side surface in a tire meridian cross section.

[0080] [Aspect 8] The pneumatic tire according to the present disclosure includes: A pneumatic tire according to aspect 7 is provided, wherein, of the two arcs constituting the recess, the arc located on the outer side in the tire radial direction has a radius of 3 mm or more and 15 mm or less.

[0081] [Aspect 9] The pneumatic tire according to the present disclosure includes: A pneumatic tire according to aspect 7 or 8, wherein, of the two arcs constituting the recess, the arc located on the inner side in the tire radial direction has a radius of 3 mm or more and 15 mm or less.

[0082] [Aspect 10] The pneumatic tire according to the present disclosure includes: A pair of beads are disposed at inner ends of the pair of sidewalls in a tire radial direction, respectively; a carcass that is toroidally stretched between the pair of beads; a belt layer disposed between the tread and the carcass and extending in a tire circumferential direction; Equipped with A pneumatic tire according to any one of Aspects 7 to 9 is provided, wherein a distance between an end of the belt layer and the depression in the tire axial direction is 12 mm or more. [Explanation of symbols]

[0083] 1. Tires (pneumatic tires) 10 Tread 10a edge 11 Tread 12 Circumferential groove 12A Inner circumferential groove 12B Outer circumferential groove 13 land 13A Quarter Land 13B Shoulder Land 20 Sidewall 21 Basic aspects 21a Basic surface on outer diameter side 21b Inner diameter basic surface 22 Honeycomb Block Group (Block Group) 23 Corner 30 Beads 31 Bead core 32 Bead filler 40 Inner Liner 41 Carcass 42 Belt layer 42a 1st belt ply 42b 2nd belt ply 42c 3rd belt ply 42d 4th belt ply 50 Hexagonal Block (1st Block) 51 Top surface (first surface) 51a~51f Vertex 51g~51l 52,52A~52D Narrow groove (1st narrow groove) 53 holes 60, 60A, 60B Pentagonal block (2nd block) 61 Top surface (2nd surface) 61a~61e Vertex Around 61f~61j 62 Narrow groove (2nd narrow groove) 70 Depression 71 Outer diameter arc 72 Inner diameter arc CL Tire Equator PL parting line VL Virtual Line

Claims

1. Tread and a sidewall extending radially inward from an axial end of the tread; Equipped with The sidewall is An outer diameter side basic surface arranged on the tire radial direction outer side of a maximum width position where the width of the sidewall in the tire axial direction is maximum, among the tire side surfaces; a plurality of first blocks each having a hexagonal first surface arranged at intervals from the outer diameter side basic surface outward in the tire axial direction and arranged side by side in the tire circumferential direction; a plurality of second blocks each having a polygonal second surface disposed at an interval from the outer diameter side basic surface to the outside in the tire axial direction, the second blocks being disposed side by side in the tire circumferential direction on the inside or outside of the plurality of first blocks in the tire radial direction, and being disposed in a honeycomb pattern on the plurality of first blocks; Equipped with At least one first narrow groove recessed from the first surface toward the inside in the tire axial direction is disposed in each first block.

2. the at least one first narrow groove includes a plurality of first narrow grooves, The pneumatic tire according to claim 1 , wherein the plurality of first narrow grooves are arranged so as to divide the first surface into a plurality of triangles.

3. The first surface has a pair of opposite sides extending in a tire radial direction and spaced apart in a tire circumferential direction, 3. The pneumatic tire according to claim 2, wherein the plurality of first narrow grooves are composed of four first narrow grooves arranged on four diagonal lines respectively connecting an inner end in the tire radial direction and an outer end in the tire radial direction of each of the pair of opposite sides.

4. 4. The pneumatic tire according to claim 3, wherein each first block has a hole disposed at an intersection of two intersecting first narrow grooves among the four first narrow grooves, the hole extending from the first surface to an inner side in the tire axial direction from bottom surfaces of the two first narrow grooves.

5. The pneumatic tire according to claim 1 , wherein each second block has at least one second narrow groove disposed therein, the second narrow groove being recessed from the second surface toward an inner side in the tire axial direction.

6. 2. The pneumatic tire according to claim 1, wherein a corner between each second block and a portion of the tire side opposite the plurality of first blocks with respect to each second block is an arc having a radius of 3 mm or more and 15 mm or less.

7. a recess is disposed in an area of ​​the tire sidewall located 1 mm or more and 20 mm or less radially inward from an end of the tread in the tire axial direction, the recess being recessed axially inward from the tire sidewall, The pneumatic tire according to claim 1 , wherein the recess is formed by two arcs having centers on the outer side in the tire axial direction with respect to the tire side surface in a tire meridian cross section.

8. The pneumatic tire according to claim 7 , wherein of the two arcs constituting the recess, the arc located on the outer side in the tire radial direction has a radius of 3 mm or more and 15 mm or less.

9. The pneumatic tire according to claim 7 , wherein of the two arcs constituting the recess, the arc located on the inner side in the tire radial direction has a radius of 3 mm or more and 15 mm or less.

10. A pair of beads are disposed at inner ends of the pair of sidewalls in the tire radial direction, respectively; a carcass that is toroidally stretched between the pair of beads; a belt layer disposed between the tread and the carcass and extending in a tire circumferential direction; Equipped with The pneumatic tire according to claim 7 , wherein a distance between an end of the belt layer and the depression in the tire axial direction is 12 mm or more.

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