Pneumatic tire

Abstract

To provide a pneumatic tire that can secure traction performance, while suppressing rigidity of a land from deteriorating.SOLUTION: A pneumatic tire 1 comprises, at a tread 11: a plurality of first sipes 17 extending in a tire axial direction TW along a plurality of first dividing grooves 15, at respective groove bottoms of the plurality of first dividing grooves 15, in which groove depths D4 thereof are equal to 80-90% of groove depths D1 and D2 of a plurality of circumferential grooves 12, 13a and 13b; and a plurality of second sipes 18 having lengths shorter than lengths of the plurality of first sipes 17, which extend in the tire axial direction TW along a plurality of second dividing grooves 16, at respective groove bottoms of the plurality of second dividing grooves 16 and in which groove depths D6 thereof are equal to 80-90% of the groove depths D1 and D2 of the plurality of circumferential grooves 12, 13a and 13b.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Patent Document 1 discloses a pneumatic tire having, in its tread, lateral grooves extending in the tire axial direction between a plurality of circumferential grooves, and sipes extending in the tire axial direction along the lateral grooves at the groove bottoms of the lateral grooves. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-55013 Summary of the Invention [Problem to be solved by the invention]

[0004] The pneumatic tire of Patent Document 1 is likely to ensure drainage performance and traction performance due to the lateral grooves when the pneumatic tire is new or when the tread is in the early stages of wear. Furthermore, after the tread wear progresses and the lateral grooves disappear, the tire of Patent Document 1 is likely to exhibit traction performance while suppressing excessive reduction in rigidity of the land between the multiple circumferential grooves due to the sipes.

[0005] On the other hand, the tire of Patent Document 1 has axially extending sipes at the bottom of the lateral grooves that are deeper than the lateral grooves, so that the decrease in rigidity of the land cannot be sufficiently suppressed. Therefore, the pneumatic tire of Patent Document 1 is prone to accelerated wear of the land.

[0006] Therefore, an object of the present invention is to provide a pneumatic tire that can ensure traction performance while suppressing a decrease in rigidity on land. [Means for solving the problem]

[0007] First, one aspect of the present invention is a tread comprising: a plurality of circumferential grooves extending in the tire circumferential direction; A plurality of lands defined between the plurality of circumferential grooves; a plurality of first dividing grooves and a plurality of second dividing grooves that are alternately arranged at intervals in the tire circumferential direction and extend in the tire axial direction between the plurality of circumferential grooves so as to divide the plurality of lands in the tire circumferential direction, and have a groove depth of 15 to 20% of the groove depth of the plurality of circumferential grooves; A plurality of dividing lands, each of which is divided in the tire circumferential direction by the plurality of first dividing grooves and the plurality of second dividing grooves; a plurality of first sipes extending in the tire axial direction along each of the plurality of first dividing grooves at the groove bottoms of each of the plurality of first dividing grooves, the groove depth being 80 to 90% of the groove depth of each of the plurality of circumferential grooves; a plurality of second sipes at the groove bottoms of the second dividing grooves, the second sipes having a length shorter than the length of the plurality of first sipes, extending in the tire axial direction along the second dividing grooves, and having a groove depth of 80 to 90% of the groove depth of the plurality of circumferential grooves; To provide a pneumatic tire comprising:

[0008] According to the present invention, the plurality of first dividing grooves and the plurality of second dividing grooves extend in the tire axial direction between the plurality of circumferential grooves, and have a groove depth of 15 to 20% of the groove depth of the plurality of circumferential grooves. With this feature, when the pneumatic tire is new or when the tread is in the early stage of wear, traction performance is easily ensured, and because the groove depths of the plurality of first dividing grooves and the plurality of second dividing grooves are not too deep, a decrease in land rigidity is suppressed, and the land is less likely to wear. If the groove depth of the plurality of first dividing grooves and the plurality of second dividing grooves is less than 15% of the groove depth of the plurality of circumferential grooves, the plurality of first dividing grooves and the plurality of second dividing grooves will disappear early as the tread wear progresses, making it difficult to ensure traction performance. If the groove depth of the plurality of first dividing grooves and the plurality of second dividing grooves exceeds 20% of the groove depth of the plurality of circumferential grooves, the groove depth of the plurality of first dividing grooves and the plurality of second dividing grooves will be too deep, which will tend to reduce the rigidity of the land and make it difficult to suppress wear of the land. Furthermore, the plurality of first sipes and the plurality of second sipes, each shorter than the length of the plurality of first sipes, extend in the axial direction of the tire along the plurality of first dividing grooves and the plurality of second dividing grooves at the groove bottoms of the plurality of first dividing grooves and the plurality of second dividing grooves, which are alternately arranged at intervals in the tire circumferential direction. With this feature, a decrease in the rigidity of the land is suppressed compared to when the plurality of second sipes have the same length as the plurality of first sipes, making the land less susceptible to wear. Furthermore, the groove depth of the first sipes and the second sipes is 80 to 90% of the groove depth of the circumferential grooves. This feature makes it easy to ensure traction performance, and because the groove depths of the first sipes and the second sipes are not too deep, a decrease in the rigidity of the land is suppressed, making the land less susceptible to wear. If the groove depth of the multiple first sipes and multiple second sipes is less than 80% of the groove depth of the multiple circumferential grooves, as the tread wear progresses, the multiple first sipes and multiple second sipes will wear out early, making it difficult to ensure traction performance. If the groove depth of the multiple first sipes and multiple second sipes exceeds 90% of the groove depth of the multiple circumferential grooves, the groove depth of the multiple first sipes and multiple second sipes will be too deep, which will tend to reduce the rigidity of the land and make it difficult to suppress wear on the land. Therefore, the pneumatic tire according to the present invention can ensure both traction performance and suppress wear on land. [Effects of the Invention]

[0009] Therefore, the pneumatic tire according to the present invention can ensure traction performance while suppressing a decrease in rigidity on land. [Brief explanation of the drawings]

[0010] [Figure 1]1 is a schematic view of a tread of a pneumatic tire according to an embodiment of the present invention, viewed from the radially outer side. [Figure 2] 2 is a radial cross-sectional view of the tire taken along line II in FIG. 1; [Figure 3] FIG. 2 is a radial cross-sectional view of the tire taken along line III in FIG. 1 . [Figure 4] FIG. 4 is a radial cross-sectional view of the tire taken along line IV in FIG. 1 . [Figure 5] FIG. 2 is a radial cross-sectional view of the tire taken along line V in FIG. 1 . [Figure 6] FIG. 2 is a radial cross-sectional view of the tire taken along line VI in FIG. 1 . [Figure 7] FIG. 7 is a radial cross-sectional view of the tire taken along line VII in FIG. [Figure 8] FIG. 8 is a cross-sectional view in the tire radial direction taken along line VIII in FIG. [Figure 9] 2 is a radial cross-sectional view of the tire taken along line IX in FIG. 1; [Figure 10] FIG. 2 is a radial cross-sectional view of the tire taken along line X in FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0012] FIG. 1 is a schematic diagram of the tread of a pneumatic tire (hereinafter simply referred to as "tire") according to one embodiment of the present invention, viewed from the radially outer side. The tire 1 of this embodiment is configured as a heavy-duty rubber tire. Heavy-duty tires are tires defined in the JATMA YEAR BOOK (Chapter C: for trucks and buses, Chapter D: for construction vehicles). In this embodiment, the left-right direction in FIG. 1 is referred to as the tire axial direction TW, and the up-down direction in FIG. 1 is referred to as the tire circumferential direction TC. In particular, within the tire axial direction TW, the rightward direction in FIG. 1 is referred to as TW1, and the leftward direction in FIG. 1 is referred to as TW2. Furthermore, within the tire circumferential direction TC, the upward direction in FIG. 1 is referred to as TC1, and the downward direction in FIG. 1 is referred to as TC2.

[0013] [Tire structure] The tire 1 has a tread 11 extending in the tire circumferential direction TC so as to extend cylindrically around the axis of the tire 1, and ground contact edges 11a, 11b located at both ends in the tire axial direction TW of the tread 11. The tread 11 is located at the outer end in the tire radial direction and has a tread surface 11c that is the contact surface that comes into contact with the ground when the tire rolls.

[0014] The tread 11 has a center circumferential groove 12 extending in a zigzag pattern in the tire circumferential direction TC, and a pair of shoulder circumferential grooves 13a, 13b located on both sides of the center circumferential groove 12 in the tire axial direction TW and extending in a zigzag pattern in the tire circumferential direction TC. The center circumferential groove 12 and the pair of shoulder circumferential grooves 13a, 13b are each recessed from the tread surface 11c toward the tire radially inward.

[0015] The center circumferential groove 12 is located on the center side of the tread 11 in the tire axial direction TW. In this embodiment, the center circumferential groove 12 is located on the tire equator CL, but it does not necessarily have to be located on the tire equator CL. The center circumferential groove 12 extends in a zigzag pattern along the tire circumferential direction TC. Specifically, the center circumferential groove 12 has a plurality of first bent portions 12a bent convexly in the tire axial direction TW1 and a plurality of second bent portions 12b bent convexly in the tire axial direction TW2. The plurality of first bent portions 12a and the plurality of second bent portions 12b are alternately arranged along the tire circumferential direction TC.

[0016] The central circumferential groove 12 includes a pair of groove wall surfaces 30A, 30B, a groove bottom surface 40 connecting the tire radially inner ends of the pair of groove wall surfaces 30A, 30B, and a protrusion 50 protruding radially outward from the groove bottom surface 40. In the following description, when there is no need to particularly distinguish between the pair of groove wall surfaces 30A, 30B, one of the pair of groove wall surfaces 30A, 30B may be simply referred to as groove wall surface 30.

[0017] The groove wall surface 30 extends in a zigzag pattern along the tire circumferential direction TC. Specifically, the groove wall surface 30 is bent convexly in the tire axial direction TW1 at the first bend portion 12a, and is bent convexly in the tire axial direction TW2 at the second bend portion 12b.

[0018] The protrusion 50 extends in a zigzag pattern along the tire circumferential direction TC. In other words, the protrusion 50 extends in the direction in which the central circumferential groove 12 extends. Specifically, the protrusion 50 is bent convexly in the tire axial direction TW1 at the first bent portion 12a, and is bent convexly in the tire axial direction TW2 at the second bent portion 12b.

[0019] The protrusion 50 is divided at predetermined intervals in the tire circumferential direction TC. Specifically, the protrusion 50 is composed of a plurality of first protrusions 50a and a plurality of second protrusions 50b arranged at intervals in the tire circumferential direction TC. Each first protrusion 50a is bent convexly in the tire axial direction TW1 at the first bend portion 12a. Each second protrusion 50b is bent convexly in the tire axial direction TW2 at the second bend portion 12b. The plurality of first protrusions 50a and the plurality of second protrusions 50b are alternately arranged along the tire circumferential direction TC, so that the protrusion 50 as a whole extends in a zigzag pattern along the tire circumferential direction TC. The first protrusions 50a and the second protrusions 50b are arranged at intervals d along the direction in which the center circumferential groove 12 extends. In this embodiment, the interval d is set to 2.5 mm. The distance d is preferably 11% or more and 16% or less of the length of the first projection 50a or the second projection 50b along the direction in which the center circumferential groove 12 extends.

[0020] Fig. 2 is a radial cross-sectional view of the tire taken along line II in Fig. 1, showing a cross section of the central circumferential groove 12. The central circumferential groove 12 has a predetermined groove depth D1. In this embodiment, the groove depth D1 is set to 17 mm.

[0021] The groove wall surface 30 extends radially inward from the tread surface 11c. Specifically, the groove wall surface 30 includes a first wall surface 31 extending from the tread surface 11c along the tire radial direction, and a second wall surface 32 extending from the groove bottom surface 40 along the tire radial direction.

[0022] The first wall surface 31 of this embodiment extends from the tread surface 11c toward the inside in the tire radial direction, slanting toward the center of the center circumferential groove 12 in the tire axial direction TW. Specifically, the first wall surface 31 of the groove wall surface 30A extends from the tread surface 11c toward the inside in the tire radial direction, slanting toward the groove wall surface 30B in the tire axial direction TW, i.e., slanting linearly in the tire axial direction TW2. The first wall surface 31 of the groove wall surface 30B extends from the tread surface 11c toward the inside in the tire radial direction, slanting toward the groove wall surface 30A in the tire axial direction TW, i.e., slanting linearly in the tire axial direction TW1.

[0023] In this embodiment, the inclination angle θ1 of the first wall surface 31 with respect to the tire radial direction is 10° in a cross section (for example, the cross section shown in FIG. 2) perpendicular to the extension direction of the central circumferential groove 12. The inclination angle θ1 of the first wall surface 31 with respect to the tire radial direction is preferably 5° or more and 15° or less in a cross section perpendicular to the extension direction of the central circumferential groove 12.

[0024] In this embodiment, the dimension H1 of the first wall surface 31 in the tire radial direction is 65% of the dimension of the central circumferential groove 12 in the tire radial direction, i.e., the groove depth D1. The dimension H1 of the first wall surface 31 in the tire radial direction is preferably 60% or more and 70% or less of the groove depth D1 of the central circumferential groove 12.

[0025] Although the first wall surface 31 in this embodiment is linear and inclined from the tread surface 11c, this is not limiting. The first wall surface 31 may extend, as a whole, from the tread surface 11c toward the tire radially inward direction so as to approach the center of the central circumferential groove 12 in the tire axial direction TW. For example, the first wall surface 31 may extend from the tread surface 11c toward the tire radially inward direction parallel to the tire radial direction, and then extend toward the tire radially inward direction, inclined toward the center of the central circumferential groove 12 in the tire axial direction TW. In other words, the first wall surface 31 may have a vertical wall portion extending from the tread surface 11c toward the tire radially inward direction parallel to the tire radial direction, and an inclined portion extending from the tire radially inner end of the vertical wall portion toward the tire radially inward direction, inclined toward the center of the central circumferential groove 12 in the tire axial direction TW.

[0026] The second wall surface 32 of this embodiment is disposed contiguous to the groove bottom surface 40 and extends radially outward in the tire direction, inclined away from the center of the center circumferential groove 12 in the tire axial direction TW. In other words, the second wall surface 32 extends radially inward in the tire direction, inclined toward the center of the center circumferential groove 12 in the tire axial direction TW. Specifically, the second wall surface 32 of the groove wall surface 30A extends radially inward in the tire direction, inclined toward the groove wall surface 30B in the tire axial direction TW2, i.e., inclined linearly in the tire axial direction TW2. The second wall surface 32 of the groove wall surface 30B extends radially inward in the tire direction, inclined toward the groove wall surface 30A in the tire axial direction TW, i.e., inclined linearly in the tire axial direction TW1.

[0027] In this embodiment, the inclination angle θ2 of the second wall surface 32 with respect to the tire radial direction is 5° in a cross section (for example, the cross section shown in FIG. 2) perpendicular to the extension direction of the central circumferential groove 12. The inclination angle θ2 of the second wall surface 32 with respect to the tire radial direction is preferably 0° or more and 5° or less in a cross section perpendicular to the extension direction of the central circumferential groove 12.

[0028] In this embodiment, the outer end of the second wall surface 32 in the tire radial direction is connected to the inner end 31a of the first wall surface 31 in the tire radial direction. That is, the second wall surface 32 in this embodiment is continuous with the first wall surface 31.

[0029] The protrusion 50 protrudes from the groove bottom surface 40 outward in the tire radial direction. The protrusion 50 of this embodiment has a rectangular shape in a cross section perpendicular to the direction in which the center circumferential groove 12 extends (for example, the cross section shown in FIG. 2). The protrusion 50 includes a pair of side surfaces 51A, 51B extending from the groove bottom surface 40 outward in the tire radial direction, and an upper surface 52 connecting the outer ends of the pair of side surfaces 51A, 51B in the tire radial direction. In the following description, when there is no need to particularly distinguish between the pair of side surfaces 51A, 51B, one of these may be simply referred to as side surface 51.

[0030] The upper surface 52 of the protrusion 50, i.e., the tire radially outer end of the protrusion 50, is located radially inward of the tire radially inner end 31a of the first wall surface 31. In this embodiment, the tire radial dimension of the protrusion 50, i.e., the height H2, is 20% of the tire radial dimension of the central circumferential groove 12, i.e., the groove depth D1. The height H2 of the protrusion 50 is preferably 15% to 30% of the groove depth D1 of the central circumferential groove 12.

[0031] The side surface 51A is disposed opposite the groove wall surface 30A. The side surface 51B is disposed opposite the groove wall surface 30B. The side surface 51 extends from the groove bottom surface 40 toward the tire radially outward, inclining toward the center of the center circumferential groove 12 in the tire axial direction TW. Specifically, the side surface 51A extends from the groove bottom surface 40 toward the tire radially outward, inclining in the tire axial direction TW2. The side surface 51B extends from the groove bottom surface 40 toward the tire radially outward, inclining in the tire axial direction TW1. The inclination angle θ3 of the side surface 51 with respect to the tire radial direction is 5° in a cross section (for example, the cross section shown in FIG. 2) perpendicular to the extension direction of the center circumferential groove 12. The inclination angle θ3 of the side surface 51 with respect to the tire radial direction is preferably 0° or more and 5° or less in a cross section (for example, the cross section shown in FIG. 2) perpendicular to the extension direction of the center circumferential groove 12. The space between the side surface 51 and the groove wall surface 30 is defined so as to gradually increase outward in the tire radial direction.

[0032] The groove bottom surface 40 is disposed contiguous with the groove wall surfaces 30A, 30B, respectively, and includes a pair of first curved surfaces 41A, 41B that extend in a curved manner in a cross section (for example, the cross section shown in FIG. 2) perpendicular to the direction in which the center circumferential groove 12 extends. When there is no need to particularly distinguish between the pair of first curved surfaces 41A, 41B, one of these may be simply referred to as the first curved surface 41. The first curved surface 41A extends in a concave curve in the tire axial direction TW2 from the groove wall surface 30A toward the tire radially inward. The first curved surface 41B extends in a concave curve in the tire axial direction TW1 from the groove wall surface 30B toward the tire radially inward.

[0033] The groove bottom surface 40 is disposed contiguous with the side surfaces 51A, 51B of the protrusion 50, respectively, and includes a pair of second curved surfaces 42A, 42B that extend in a curved manner in a cross section (for example, the cross section shown in FIG. 2) perpendicular to the direction in which the center circumferential groove 12 extends. When there is no need to particularly distinguish between the pair of second curved surfaces 42A, 42B, one of these may be simply referred to as the second curved surface 42. The second curved surface 42A extends in a concave curve in the tire axial direction TW1 from the side surface 51A of the protrusion 50 toward the tire radially inward. The second curved surface 42B extends in a concave curve in the tire axial direction TW2 from the side surface 51B of the protrusion 50 toward the tire radially inward.

[0034] The second curved surface 42 of this embodiment is disposed contiguous to the first curved surface 41. In addition, in a cross section perpendicular to the direction in which the central circumferential groove 12 extends (for example, the cross section shown in FIG. 2), the curvature of the second curved surface 42 is smaller than the curvature of the first curved surface 41. In other words, in a cross section perpendicular to the direction in which the central circumferential groove 12 extends (for example, the cross section shown in FIG. 2), the curvature radius r1 of the first curved surface 41 is larger than the curvature radius r2 of the second curved surface 42.

[0035] Fig. 3 is a radial cross-sectional view of the tire taken along line III in Fig. 1, showing a cross section of the pair of shoulder circumferential grooves 13a, 13b. The pair of shoulder circumferential grooves 13a, 13b have a predetermined groove depth D2.

[0036] 1, the tread 11 has a pair of center lands 14a, 14b defined between the center circumferential groove 12 and the pair of shoulder circumferential grooves 13a, 13b. The tread 11 also has a plurality of first center dividing grooves 15 and a plurality of second center dividing grooves 16 that are alternately arranged at intervals in the tire circumferential direction TC and extend in the tire axial direction TW between the center circumferential groove 12 and the pair of shoulder circumferential grooves 13a, 13b so as to divide the pair of center lands 14a, 14b in the tire circumferential direction TC. The plurality of first center dividing grooves 15 and the plurality of second center dividing grooves 16 are connected to the center circumferential groove 12 and the pair of shoulder circumferential grooves 13a, 13b, respectively.

[0037] The first center dividing groove 15 extends from the tire axial direction TW2 toward the tire axial direction TW1 and is inclined from the tire circumferential direction TC2 toward the tire circumferential direction TC1. The second center dividing groove 16 extends in a zigzag manner from the tire axial direction TW2 toward the tire axial direction TW1 and is inclined from the tire circumferential direction TC1 toward the tire circumferential direction TC2. The second center dividing groove 16 extends in a zigzag manner in the tire axial direction TW by connecting at least three or more small grooves inclined at different angles with respect to the tire axial direction TW. In this embodiment, the second center dividing groove 16 has a first dividing small groove 16a, a second dividing small groove 16b, and a third dividing small groove 16c inclined at different angles with respect to the tire axial direction TW from the tire axial direction TW2 toward the tire axial direction TW1. The first dividing small groove 16a, the second dividing small groove 16b, and the third dividing small groove 16c are connected to each other, so that the second center dividing groove 16 extends in a zigzag manner in the tire axial direction TW.

[0038] Each of the pair of shoulder circumferential grooves 13a, 13b has a plurality of small grooves inclined at different angles with respect to the tire circumferential direction TC, and the plurality of small grooves are connected to each other to form a zigzag shape in the tire circumferential direction TC. In particular, each of the pair of shoulder circumferential grooves 13a, 13b has a first shoulder circumferential small groove 13c at a position where it communicates with the plurality of first center dividing grooves 15, extending from the tire circumferential direction TC2 toward the tire circumferential direction TC1 and inclined from the tire axial direction TW2 toward the tire axial direction TW1. Furthermore, each of the pair of shoulder circumferential grooves 13a, 13b has a second shoulder circumferential small groove 13d at a position where it communicates with the plurality of second center dividing grooves 16, extending from the tire circumferential direction TC2 toward the tire circumferential direction TC1 and inclining from the tire axial direction TW2 toward the tire axial direction TW1. The angle A1 at which the first shoulder circumferential small groove 13c is inclined with respect to the tire axial direction TW is the same as the angle A2 at which the second shoulder circumferential small groove 13d is inclined with respect to the tire axial direction TW.

[0039] Each of the pair of center lands 14a, 14b has a first center dividing land 14c and a second center dividing land 14d that are divided in the tire circumferential direction TC by a plurality of first center dividing grooves 15 and a plurality of second center dividing grooves 16. The length of the first center dividing land 14c along the tire circumferential direction TC on the tire axial direction TW1 side is greater than the length of the second center dividing land 14d along the tire circumferential direction TC on the tire axial direction TW2 side. The first center dividing land 14c and the second center dividing land 14d are positioned alternately in the tire circumferential direction TC so as to be adjacent to each other in the pair of center lands 14a, 14b.

[0040] 4 is a tire radial cross-sectional view taken along line IV in FIG. 1, showing a cross-section of the first center dividing groove 15. The first center dividing groove 15 has a groove depth D3 from the tread surface 11c to the groove bottom. The groove depth D3 of the first center dividing groove 15 is set to 15 to 20% of the groove depth D1 of the center circumferential groove 12. In this embodiment, the groove depth D3 of the first center dividing groove 15 is set to 2.9 mm.

[0041] The first center dividing groove 15 has, at its groove bottom, a first sipe 17 extending in the tire axial direction TW along the first center dividing groove 15. The first sipe 17 has a groove depth D4 from the tread surface 11c to the groove bottom. The groove depth D4 of the first sipe 17 is set to 80 to 90% of the groove depth D1 of the center circumferential groove 12. In this embodiment, the groove depth D4 of the first sipe 17 is set to 15.2 mm.

[0042] 5 is a radial cross-sectional view of the tire taken along line V in FIG. 1, showing a cross-section of the first sipe 17. The first sipe 17 has a stepped shape in which the groove bottoms on both ends in the tire axial direction TW are higher than the groove bottom on the central side. Therefore, the groove depth of the first sipe 17 at the center in the tire axial direction TW is deeper than the groove depth at both ends in the tire axial direction TW.

[0043] 1, the first sipe 17 has bent portions 17a at both ends in the tire axial direction TW that are substantially perpendicular to the center circumferential groove 12 or the shoulder circumferential grooves 13a, 13b. The state in which the bent portions 17a are substantially perpendicular to the center circumferential groove 12 or the shoulder circumferential grooves 13a, 13b means that the bent portions 17a intersect with the center circumferential groove 12 or the shoulder circumferential grooves 13a, 13b at an angle of 85 degrees or more and 92 degrees or less.

[0044] 6 is a tire radial cross-sectional view taken along line VI in FIG. 1, showing a cross-section of the second center dividing groove 16. The second center dividing groove 16 has a groove depth D5 from the tread surface 11c to the groove bottom. The groove depth D5 of the second center dividing groove 16 is set to 15 to 20% of the groove depth D1 of the center circumferential groove 12. In this embodiment, the groove depth D5 of the second center dividing groove 16 is set to 2.9 mm.

[0045] The second center dividing groove 16 has, at its groove bottom, a second sipe 18 extending in the tire axial direction TW along the second center dividing groove 16. The second sipe 18 has a groove depth D6 from the tread surface 11c to the groove bottom. The groove depth D6 of the second sipe 18 is set to 80 to 90% of the groove depth D1 of the center circumferential groove 12. In this embodiment, the groove depth D6 of the second sipe 18 is set to 15.2 mm.

[0046] 7 is a radial cross-sectional view of the tire taken along line VII in FIG. 1, showing a cross-section of the second sipe 18. The second sipe 18 has a shape with a uniform groove depth. Therefore, the groove depth of the second sipe 18 at the center in the tire axial direction TW is approximately equal to the groove depth at both ends in the tire axial direction TW.

[0047] As shown in FIG. 1, the length of the second sipes 18 in the tire axial direction TW is shorter than the length of the first sipes 17 in the tire axial direction TW.

[0048] The first center dividing land 14c has a first narrow groove 19a that extends in the tire circumferential direction TC1 from the end on the tire axial direction TW1 side of the second dividing small groove 16b located at the center of the second center dividing groove 16 in the tire axial direction TW, inclined in the tire axial direction TW2 toward the center of the first center dividing land 14c, and closed at the center of the first center dividing land 14c. The second center dividing land 14d has a second narrow groove 19b that extends in the tire circumferential direction TC2 from the end on the tire axial direction TW2 side of the second dividing small groove 16b located at the center of the second center dividing groove 16 in the tire axial direction TW, inclined in the tire axial direction TW1 toward the center of the second center dividing land 14d, and closed at the center of the second center dividing land 14d. The first narrow groove 19a and the second narrow groove 19b extend parallel to each other and have the same groove width and groove depth.

[0049] The minimum distance D7 between the first narrow groove 19a and the second narrow groove 19b along the tire axial direction TW is within 2 mm. In this embodiment, the minimum distance D7 between the first narrow groove 19a and the second narrow groove 19b along the tire axial direction TW is set to 2 mm.

[0050] FIG. 8 is a radial cross-sectional view of the tire taken along line VIII in FIG. 1, showing a cross-section of the first narrow groove 19a. The first narrow groove 19a has a groove depth D8 from the tread surface 11c to the groove bottom. The dimension of the groove depth D8 of the first narrow groove 19a is within 1 mm. In this embodiment, the dimension of the groove depth D8 of the first narrow groove 19a is set to 1 mm. The second narrow groove 19b also has a cross-sectional shape similar to that of the first narrow groove 19a.

[0051] 1, the tread 11 has a pair of shoulder lands 20a, 20b defined between the pair of shoulder circumferential grooves 13a, 13b and the ground contact edges 11a, 11b of the tread 11. The tread 11 also has a plurality of shoulder dividing grooves 21 that are alternately arranged at intervals in the tire circumferential direction TC and extend in a zigzag pattern in the tire axial direction TW between the pair of shoulder circumferential grooves 13a, 13b and the ground contact edges 11a, 11b of the tread 11. The shoulder dividing grooves 21 are inclined at an angle A3 with respect to the tire circumferential direction TW, and the zigzag shape of the shoulder dividing grooves 21 is greater than the angles A1 and A2 with respect to the tire circumferential direction.

[0052] Fig. 9 is a radial cross-sectional view of the tire taken along line IX in Fig. 1, showing a cross-section of the shoulder dividing groove 21. The shoulder dividing groove 21 has, at the groove bottom, a shoulder sipe 22 extending in the tire axial direction along the shoulder dividing groove 21. As shown in Fig. 1, the shoulder sipe 22 is divided in the tire axial direction and has a first divided sipe 22a and a second divided sipe 22b.

[0053] 10 is a radial cross-sectional view of the tire taken along line X in FIG. 1, showing a cross-section of the shoulder sipe 22. The first divided sipe 22a and the second divided sipe 22b each have a shape with a uniform groove depth. The axial length of the second divided sipe 22b is longer than the axial length of the first divided sipe 22a.

[0054] [Action and effect] The tire 1 configured in this manner has the following features.

[0055] Tire 1 is Tread 11, a center circumferential groove 12 and a pair of shoulder circumferential grooves 13a, 13b extending in the tire circumferential direction TC; a pair of center lands 14a, 14b defined between the center circumferential groove 12 and the pair of shoulder circumferential grooves 13a, 13b; a plurality of first center dividing grooves 15 and a plurality of second center dividing grooves 16 that are alternately arranged at intervals in the tire circumferential direction TC and extend in the tire axial direction TW between the center circumferential groove 12 and the pair of shoulder circumferential grooves 13a, 13b so as to divide the pair of center lands 14a, 14b in the tire circumferential direction TC, and that have groove depths D3, D5 that are 15 to 20% of the groove depth D1 of the center circumferential groove 12; In the pair of center lands 14a, 14b, a plurality of first center dividing lands 14c and a plurality of second center dividing lands 14d are divided in the tire circumferential direction TC by a plurality of first center dividing grooves 15 and a plurality of second center dividing grooves 16, a plurality of first sipes 17 extending in the tire axial direction TW along each of the plurality of first center dividing grooves 15 at the groove bottoms of each of the plurality of first center dividing grooves 15, and having a groove depth D4 of 80 to 90% of the groove depth D1 of the center circumferential groove 12; a plurality of second sipes 18 at the bottoms of the second center dividing grooves 16, the second sipes 18 having a length shorter than the length of the first sipes 17, extending along the second center dividing grooves 16 in the tire axial direction TW, and having a groove depth D6 that is 80 to 90% of the groove depth D1 of the center circumferential groove 12; Equipped with.

[0056] According to the present invention, the plurality of first center dividing grooves 15 and the plurality of second center dividing grooves 16 extend in the tire axial direction TW between the center circumferential groove 12 and the pair of shoulder circumferential grooves 13a, 13b, and the groove depths D3, D5 are 15 to 20% of the groove depth D1 of the center circumferential groove 12. This feature makes it easy to ensure traction performance when the tire 1 is new or when the tread 11 is in the early stage of wear, and because the groove depths D3, D5 of the plurality of first center dividing grooves 15 and the plurality of second center dividing grooves 16 are not too deep, a decrease in the rigidity of the pair of center lands 14a, 14b is suppressed, making the pair of center lands 14a, 14b less susceptible to wear. If the groove depths D3, D5 of the plurality of first center dividing grooves 15 and the plurality of second center dividing grooves 16 are less than 15% of the groove depth D1 of the central circumferential groove 12, the plurality of first center dividing grooves 15 and the plurality of second center dividing grooves 16 will disappear early as the wear of the tread 11 progresses, making it difficult to ensure traction performance. If the groove depths D3, D5 of the plurality of first center dividing grooves 15 and the plurality of second center dividing grooves 16 exceed 20% of the groove depth D1 of the center circumferential groove 12, the groove depths D3, D5 of the plurality of first center dividing grooves 15 and the plurality of second center dividing grooves 16 are too deep, which tends to reduce the rigidity of the pair of center lands 14a, 14b and makes it difficult to suppress wear of the pair of center lands 14a, 14b. Furthermore, the plurality of first sipes 17 and the plurality of second sipes 18, each shorter than the plurality of first sipes 17, extend in the tire axial direction TW along the plurality of first center dividing grooves 15 and the plurality of second center dividing grooves 16 at the groove bottoms of the plurality of first center dividing grooves 15 and the plurality of second center dividing grooves 16, which are alternately arranged at intervals in the tire circumferential direction TC. Due to this feature, a decrease in the rigidity of the pair of center lands 14a, 14b is suppressed compared to when the plurality of second sipes 18 have the same length as the plurality of first sipes 17, making the pair of center lands 14a, 14b less susceptible to wear. Furthermore, the groove depths D4, D6 of the plurality of first sipes 17 and the plurality of second sipes 18 are 80 to 90% of the groove depth D1 of the central circumferential groove 12. This feature makes it easy to ensure traction performance, and because the groove depths D4, D6 of the plurality of first sipes 17 and the plurality of second sipes 18 are not too deep, a decrease in the rigidity of the pair of center lands 14a, 14b is suppressed, making the pair of center lands 14a, 14b less susceptible to wear. If the groove depths D4, D6 of the multiple first sipes 17 and the multiple second sipes 18 are less than 80% of the groove depth D1 of the center circumferential groove 12, as the wear of the tread 11 progresses, the multiple first sipes 17 and the multiple second sipes 18 will wear out early, making it difficult to ensure traction performance. If the groove depths D4, D6 of the multiple first sipes 17 and the multiple second sipes 18 exceed 90% of the groove depth D1 of the center circumferential groove 12, the groove depths D4, D6 of the multiple first sipes 17 and the multiple second sipes 18 will be too deep, which will tend to reduce the rigidity of the pair of center lands 14a, 14b and make it difficult to suppress wear of the pair of center lands 14a, 14b. Therefore, the tire 1 according to the present invention can ensure traction performance while suppressing wear of the pair of center land portions 14a, 14b.

[0057] The first sipes 17 have bent portions 17a at both ends in the tire axial direction TW that intersect with the center circumferential groove 12 or the pair of shoulder circumferential grooves 13a, 13b at an angle of 85 degrees or more and 92 degrees or less.

[0058] According to this configuration, the plurality of first sipes 17 have bent portions 17a at both ends in the tire axial direction TW that intersect with the center circumferential groove 12 or the shoulder circumferential grooves 13a, 13b at an angle of 85 degrees or more and 92 degrees or less. Due to this feature, a part of the pair of center lands 14a, 14b defined by the plurality of first sipes 17 does not form an excessively acute angle, and the occurrence of cracks at both ends of the plurality of first sipes 17 is easily suppressed. If the bent portions 17a of the multiple first sipes 17 intersect with the center circumferential groove 12 or the shoulder circumferential grooves 13a, 13b at an angle less than 85 degrees or more than 92 degrees, a portion of the pair of center lands 14a, 14b defined by the multiple first sipes 17 will have an excessively acute angle, reducing the rigidity of the pair of center lands 14a, 14b and making cracks more likely to occur at both ends of the multiple first sipes 17.

[0059] The plurality of first sipes 17 have a groove depth at the center in the tire axial direction TW that is deeper than the groove depth at both ends in the tire axial direction TW.

[0060] According to this configuration, the groove depth of the plurality of first sipes 17 at the center in the tire axial direction TW is deeper than the groove depth at both ends in the tire axial direction TW. Due to this feature, even if the tread 11 wears, the first sipes 17 are unlikely to disappear, making it easier to ensure traction performance. In addition, since the groove depth of the curved portions 17a of the multiple first sipes 17 is shallower than the groove depth at the center in the tire axial direction, the rigidity of the pair of center lands 14a, 14b at the curved portions 17a is prevented from decreasing, making cracks less likely to occur.

[0061] The plurality of second sipes 18 extend such that their extension lines intersect with the extension lines of the plurality of first sipes 17 .

[0062] According to this configuration, the plurality of second sipes 18 extend such that their extension lines intersect with the extension lines of the plurality of first sipes 17. Due to this feature, when the pair of center lands 14a, 14b are subjected to an external force along the tire circumferential direction TC, the pair of center lands 14a, 14b are more likely to come into contact with each other to support each other than when the extension lines of the plurality of second sipes 18 extend parallel to the extension lines of the plurality of first sipes 17. This makes it easier for the pair of center lands 14a, 14b to resist the external force along the tire circumferential direction TC, and the pair of center lands 14a, 14b are less likely to wear.

[0063] Each of the plurality of second center dividing grooves 16 has a first dividing small groove 16a, a second dividing small groove 16b, and a third dividing small groove 16c that are connected to each other so as to extend in a zigzag pattern in the tire axial direction TW, The adjacent first center dividing land 14c and second center dividing land 14d each have either a first narrow groove 19a extending in the tire circumferential direction TC1 from an end on the tire axial direction TW1 side of a second dividing small groove 16b located at the center of the second center dividing groove 16 in the tire axial direction TW, inclining in the tire axial direction TW2 toward the center of the first center dividing land 14c, and closing at the center of the first center dividing land 14c, or a second narrow groove 19b extending in the tire circumferential direction TC2 from an end on the tire axial direction TW2 side of the second dividing small groove 16b located at the center of the second center dividing groove 16 in the tire axial direction TW, inclining in the tire axial direction TW1 toward the center of the second center dividing land 14d, and closing at the center of the second center dividing land 14d. The minimum distance D7 between the first narrow groove 19a and the second narrow groove 19b along the tire axial direction TW is within 2 mm.

[0064] According to this configuration, the adjacent first center separating land 14c and second center separating land 14d each have either the first narrow groove 19a or the second narrow groove 19b. This feature makes it easier to suppress skidding of the tire 1, and also suppresses a decrease in rigidity of the pair of center lands 14a, 14b, making the pair of center lands 14a, 14b less susceptible to wear, compared to when the first narrow groove 19a and the second narrow groove 19b cross the first center separating land 14c or the second center separating land 14d, respectively, and communicates with the first center separating groove 15. Furthermore, the minimum distance D7 between the first narrow groove 19a and the second narrow groove 19b in the tire axial direction TW is within 2 mm. This feature ensures that the tread surfaces 11c on both sides of the first center dividing land 14c and the second center dividing land 14d in the tire axial direction TW are sufficiently large, thereby preventing a decrease in the rigidity of the first center dividing land 14c and the second center dividing land 14d on both sides of the tire axial direction TW, and making the pair of center lands 14a, 14b less susceptible to wear.

[0065] The pair of shoulder circumferential grooves 13a, 13b extend in a zigzag pattern in the tire circumferential direction TC, The plurality of first center dividing grooves 15 and the plurality of second center dividing grooves 16 are in communication with the pair of shoulder circumferential grooves 13a, 13b, respectively. At positions where the plurality of first center dividing grooves 15 and the plurality of second center dividing grooves 16 communicate with the pair of shoulder circumferential grooves 13a, 13b, the angles A1, A2 of the pair of shoulder circumferential grooves 13a, 13b relative to the tire circumferential direction TC are the same.

[0066] According to this configuration, the angles A1, A2 of the pair of shoulder circumferential grooves 13a, 13b relative to the tire circumferential direction TC are the same at positions where the plurality of first center dividing grooves 15 and the plurality of second center dividing grooves 16 communicate with the pair of shoulder circumferential grooves 13a, 13b. Due to this feature, when the pair of center lands 14a, 14b are subjected to an external force along the tire circumferential direction TC, the first center dividing land 14c and the second center dividing land 14d tend to incline in the same direction, which tends to suppress stress concentration on the first center dividing land 14c and the second center dividing land 14d.

[0067] Tire 1 is Tread 11, Between the pair of shoulder circumferential grooves 13 a, 13 b and the ground contact edges 11 a, 11 b of the tread 11, a plurality of shoulder dividing grooves 21 are provided, which are arranged side by side at intervals in the tire circumferential direction TC and extend in a zigzag pattern in the tire axial direction TW so as to divide, in the tire circumferential direction TC, a pair of shoulder lands 20 a, 20 b defined between the pair of shoulder circumferential grooves 13 a, 13 b and the ground contact edges 11 a, 11 b of the tread 11, The angle A3 of the shoulder dividing grooves 21 relative to the tire axial direction TW is larger than the angles A1, A2 of the pair of shoulder circumferential grooves 13a, 13b relative to the tire circumferential direction TC.

[0068] According to this configuration, the tire 1 has a plurality of shoulder dividing grooves 21 in the tread 11. This feature makes it easy to ensure traction performance. Additionally, the angle A3 of the shoulder dividing grooves 21 relative to the tire axial direction TW is larger than the angles A1, A2 of the pair of shoulder circumferential grooves 13a, 13b relative to the tire circumferential direction TC. This feature ensures the edges of the shoulder dividing grooves 21, making it easier to ensure traction performance.

[0069] Tire 1 is Tread 11, At the groove bottom of each of the shoulder dividing grooves 21, a shoulder sipe 22 is provided which extends along each of the shoulder dividing grooves 21 in the tire axial direction TW and is divided in the tire axial direction TW.

[0070] According to this configuration, the tire 1 is provided in the tread 11 with shoulder sipes 22 that extend in the tire axial direction TW along each of the plurality of shoulder dividing grooves 21 at the groove bottom of each of the plurality of shoulder dividing grooves 21 and are divided in the tire axial direction TW. This feature makes it easy to ensure traction performance, and because the shoulder sipes 22 are divided, a decrease in rigidity of the pair of shoulder lands 20a, 20b is suppressed, making the pair of shoulder lands 20a, 20b less susceptible to wear.

[0071] [Other embodiments] The present invention is not limited to the configurations of the above-described embodiments, and various modifications are possible.

[0072] In the above embodiment, the center circumferential groove 12 has been described as an example of the main groove according to the present invention, but the main groove according to the present invention is not limited to the center circumferential groove 12 and may be the shoulder circumferential grooves 13a, 13b. In other words, the protrusions according to the present invention may be disposed in the shoulder circumferential grooves 13a, 13b.

[0073] In the above-described embodiment, the first center dividing groove 15, the second center dividing groove 16, the first sipe 17, and the second sipe 18 extend in the tire axial direction TW between the center circumferential groove 12 and the pair of shoulder circumferential grooves 13a, 13b, but they may also extend in the tire axial direction between other circumferential grooves, for example, between a shoulder circumferential groove and a ground contact edge of the tread.

[0074] In the above-described embodiment, the tire 1 is configured as a rubber tire for heavy loads, but may also be configured as a rubber tire for light trucks. A rubber tire for light trucks is a tire specified in the JATMA YEAR BOOK (Chapter B: For light trucks).

[0075] A first aspect of the present invention is On the tread, a plurality of circumferential grooves extending in the tire circumferential direction; A plurality of lands defined between the plurality of circumferential grooves; a plurality of first dividing grooves and a plurality of second dividing grooves that are alternately arranged at intervals in the tire circumferential direction and extend in the tire axial direction between the plurality of circumferential grooves so as to divide the plurality of lands in the tire circumferential direction, and have a groove depth of 15 to 20% of the groove depth of the plurality of circumferential grooves; A plurality of dividing lands, each of which is divided in the tire circumferential direction by the plurality of first dividing grooves and the plurality of second dividing grooves; a plurality of first sipes extending in the tire axial direction along each of the plurality of first dividing grooves at the groove bottoms of each of the plurality of first dividing grooves, the groove depth being 80 to 90% of the groove depth of each of the plurality of circumferential grooves; a plurality of second sipes at the groove bottoms of the second dividing grooves, the second sipes having a length shorter than the length of the plurality of first sipes, extending in the tire axial direction along the second dividing grooves, and having a groove depth of 80 to 90% of the groove depth of the plurality of circumferential grooves; To provide a pneumatic tire comprising:

[0076] A second aspect of the present invention is The plurality of circumferential grooves are a center circumferential groove extending in the tire circumferential direction; a pair of shoulder circumferential grooves located on both sides of the center circumferential groove in the tire axial direction and extending in the tire circumferential direction; It contains the plurality of first dividing grooves and the plurality of second dividing grooves are disposed between the center circumferential groove and the shoulder circumferential groove, The present invention provides a pneumatic tire according to a first aspect, wherein the plurality of first sipes have bent portions at both ends in the tire axial direction that intersect with the center circumferential groove or the shoulder circumferential groove at an angle of 85 degrees or more and 92 degrees or less.

[0077] A third aspect of the present invention is There is provided a pneumatic tire according to a second aspect, wherein the plurality of first sipes have a groove depth at a center in the tire axial direction that is deeper than the groove depth at both ends in the tire axial direction.

[0078] A fourth aspect of the present invention is The present invention provides a pneumatic tire according to the second or third aspect, wherein the plurality of second sipes extend such that their extension lines intersect with the extension lines of the plurality of first sipes.

[0079] A fifth aspect of the present invention is Each of the plurality of second dividing grooves has at least three or more small grooves that are connected to each other so as to extend in a zigzag pattern in the tire axial direction, the plurality of dividing lands include a plurality of center dividing lands that are partitioned between the center circumferential groove and the pair of shoulder circumferential grooves and are divided in the tire circumferential direction by the plurality of first dividing grooves and the plurality of second dividing grooves, each of the plurality of adjacent center dividing lands has either one narrow groove extending from one end of the small groove located at the center of the plurality of second dividing grooves in the tire axial direction to one side in the tire circumferential direction, inclining toward the one side in the tire axial direction toward the center of the center dividing land, and closing at the center of the center dividing land; or another narrow groove extending from the other end of the small groove located at the center of the plurality of second dividing grooves in the tire axial direction to the other side in the tire circumferential direction, inclining toward the other side in the tire axial direction toward the center of the center dividing land, and closing at the center of the center dividing land; A pneumatic tire according to any one of the second to fourth aspects is provided, wherein the minimum distance between the one narrow groove and the other narrow groove along the tire axial direction is 2 mm or less.

[0080] A sixth aspect of the present invention is The pair of shoulder circumferential grooves extend in a zigzag pattern in the tire circumferential direction, the plurality of first dividing grooves and the plurality of second dividing grooves are respectively connected to the pair of shoulder circumferential grooves, The present invention provides a pneumatic tire according to any one of the second to fifth aspects, wherein the angles of the pair of shoulder circumferential grooves relative to the tire circumferential direction are the same at positions where the plurality of first dividing grooves and the plurality of second dividing grooves communicate with the shoulder circumferential groove.

[0081] A seventh aspect of the present invention is The pneumatic tire is The tread, a plurality of shoulder dividing grooves are provided between the pair of shoulder circumferential grooves and the ground contact edge of the tread, the shoulder dividing grooves being arranged at intervals in the tire circumferential direction and extending in a zigzag pattern in the tire axial direction so as to divide in the tire circumferential direction a shoulder land defined between the pair of shoulder circumferential grooves and the ground contact edge of the tread, In a sixth aspect, there is provided a pneumatic tire, wherein an angle of the plurality of shoulder dividing grooves with respect to the tire axial direction is larger than an angle of the pair of shoulder circumferential grooves with respect to the tire circumferential direction.

[0082] An eighth aspect of the present invention is The pneumatic tire is The tread, A pneumatic tire according to a seventh aspect is provided, which is provided with shoulder sipes at the groove bottom of each of the plurality of shoulder dividing grooves, the shoulder sipes extending in the tire axial direction along each of the plurality of shoulder dividing grooves and divided in the tire axial direction. [Explanation of symbols]

[0083] 1 pneumatic tire 11 Tread 11a,11b Ground end 11c Tread 12 Center circumferential groove (circumferential groove) 13a, 13b Shoulder circumferential groove (circumferential groove) 14a, 14b Center Land 14c First Center Division Land 14d Second Center Division Land 15 First Center Dividing Ditch 16 Second Center Dividing Ditch 16a First Divided Groove 16b Second Divided Groove 16c Third Divided Groove 17 First sipe 18 Second sipe 19a 1st narrow groove 19b 2nd narrow groove 20a, 20b Shoulder Land 21 Shoulder dividing groove 22 Shoulder sipes D1, D2, D3, D4, D5, D6 groove depth D7 Minimum distance A1,A2,A3 Angle TC: Tire Circumferential Direction TW Tire axial direction

Claims

1. On the tread, A plurality of circumferential grooves extending in a circumferential direction of the tire; A plurality of lands defined between the plurality of circumferential grooves; A plurality of first dividing grooves and a plurality of second dividing grooves are arranged alternately at intervals in the tire circumferential direction between the plurality of circumferential grooves so as to divide the plurality of lands in the tire circumferential direction, and extend in the tire axial direction, and the groove depth is 15 to 20% of the groove depth of the plurality of circumferential grooves; A plurality of dividing lands, each of which is divided in a tire circumferential direction by the plurality of first dividing grooves and the plurality of second dividing grooves; A plurality of first sipes extending in the tire axial direction along each of the first dividing grooves at the bottom of each of the first dividing grooves, the groove depth being 80 to 90% of the groove depth of each of the circumferential grooves; A plurality of second sipes, which have a length shorter than a length of the plurality of first sipes at the bottom of each of the second dividing grooves, extend in the tire axial direction along each of the second dividing grooves, and have a groove depth of 80 to 90% of the groove depth of the plurality of circumferential grooves; A pneumatic tire comprising:

2. The plurality of circumferential grooves are A center circumferential groove extending in a tire circumferential direction; A pair of shoulder circumferential grooves are located on both sides of the center circumferential groove in the tire axial direction and extend in the tire circumferential direction; Contains the plurality of first dividing grooves and the plurality of second dividing grooves are disposed between the center circumferential groove and the shoulder circumferential groove, The pneumatic tire according to claim 1 , wherein the first sipes have bent portions at both ends in the tire axial direction that intersect with the center circumferential groove or the shoulder circumferential groove at an angle of 85 degrees or more and 92 degrees or less.

3. The pneumatic tire according to claim 2 , wherein the plurality of first sipes have a groove depth at a center in the tire axial direction that is deeper than the groove depths at both ends in the tire axial direction.

4. The pneumatic tire according to claim 2 or 3, wherein the second sipes extend such that their extension lines intersect with extension lines of the first sipes.

5. Each of the plurality of second dividing grooves has at least three or more small grooves that are connected to each other so as to extend in a zigzag shape in the tire axial direction, the plurality of dividing lands include a plurality of center dividing lands that are partitioned between the center circumferential groove and the pair of shoulder circumferential grooves and are divided in the tire circumferential direction by the plurality of first dividing grooves and the plurality of second dividing grooves, each of the plurality of adjacent center dividing land has either one narrow groove extending to one side in the tire circumferential direction from one end of the small groove located at the center in the tire axial direction of the plurality of second dividing grooves, inclining to one side in the tire axial direction toward the center of the center dividing land, and closing at the center of the center dividing land; or another narrow groove extending to the other side in the tire circumferential direction from the other end of the small groove located at the center in the tire axial direction of the plurality of second dividing grooves, inclining to the other side in the tire axial direction toward the center of the center dividing land, and closing at the center of the center dividing land; 4. The pneumatic tire according to claim 2, wherein a minimum distance between the one narrow groove and the other narrow groove in the tire axial direction is within 2 mm.

6. The pair of shoulder circumferential grooves extend in a zigzag pattern in the tire circumferential direction, The plurality of first dividing grooves and the plurality of second dividing grooves are respectively connected to the pair of shoulder circumferential grooves, 4. The pneumatic tire according to claim 2, wherein the pair of shoulder circumferential grooves have the same angle with respect to the tire circumferential direction at a position where the plurality of first dividing grooves and the plurality of second dividing grooves communicate with the shoulder circumferential groove.

7. The pneumatic tire is The tread has a plurality of shoulder dividing grooves are provided between the pair of shoulder circumferential grooves and the ground contact edge of the tread, the shoulder dividing grooves being arranged at intervals in the tire circumferential direction and extending in a zigzag pattern in the tire axial direction so as to divide in the tire circumferential direction a shoulder land defined between the pair of shoulder circumferential grooves and the ground contact edge of the tread, The pneumatic tire according to claim 6 , wherein angles of the shoulder dividing grooves with respect to the tire axial direction are larger than angles of the pair of shoulder circumferential grooves with respect to the tire circumferential direction.

8. The pneumatic tire is The tread has The pneumatic tire according to claim 7 , further comprising a shoulder sipe extending in the tire axial direction along each of the shoulder dividing grooves and divided in the tire axial direction at a groove bottom of each of the shoulder dividing grooves.

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