pneumatic tires

Abstract

To provide a tire capable of maintaining an edge effect and improving wear resistance.SOLUTION: A pneumatic tire comprises, on a tread 10, a first block row 18D where a plurality of first blocks 16D partitioned by main grooves 12B, 12D and lateral grooves 14E, 14F are arranged in a tire circumferential direction C. The plurality of lateral grooves 14E, 14F comprise: first lateral grooves 14E extending inclining to a tire width direction W; and second lateral grooves 14F inclining in a direction opposite to that of the first lateral grooves 14E with respect to the tire width direction W. The first and second lateral grooves 14E, 14F are alternately arranged. The first blocks 16D comprise: first sipes 24g extending inclining to the tire width direction W; second sipes 24h inclining in a direction opposite to that of the first sipes 24g with respect to the tire width direction W; and first connection parts 26a connecting ends of the first and second sipes 24g, 24h. The first connection part 26a is formed of a recess shallower than that of the first and second sipes 24g, 24h.SELECTED DRAWING: Figure 5

Description

[Technical Field]

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

[0002] Some pneumatic tires have treads with blocks formed by main grooves extending circumferentially and lateral grooves extending widthwise. To achieve an edge effect, tires with such blocks may be provided with V-shaped sipes that extend from the main groove toward the center of the block widthwise and curve within the tread of the block before extending back to the main groove (see, for example, Patent Document 1 listed below). Here, the edge effect refers to the effect of increasing grip by the corners of land portions formed by sipes, notches, etc., grabbing slippery surfaces such as snow and ice.

[0003] The V-shaped sipes described above are continuous narrow grooves, which may reduce the rigidity of the land portions and lead to an increase in uneven wear. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-167718 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a tire that can improve wear resistance while maintaining edge effect. [Means for solving the problem]

[0006] The pneumatic tire of this embodiment has a tread including a plurality of main grooves extending in the tire circumferential direction, a plurality of lateral grooves spaced apart in the tire circumferential direction, and a first block row in which a plurality of first blocks partitioned by the main grooves and the lateral grooves are lined up in the tire circumferential direction, wherein the plurality of lateral grooves include first lateral grooves extending at an angle with respect to the tire width direction and second lateral grooves that are inclined in the opposite direction to the first lateral grooves with respect to the tire width direction, and the first lateral grooves and the second lateral grooves are arranged alternately, and the first blocks include first sipes that extend at an angle with respect to the tire width direction, second sipes that are inclined in the opposite direction to the first sipes with respect to the tire width direction, and first connecting portions that connect ends of the first sipes and the second sipes, and the first connecting portions are recesses that are shallower than the first sipes and the second sipes. [Effects of the Invention]

[0007] In the present invention, by providing the above-mentioned features, it is possible to improve the wear resistance while maintaining the edge effect. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a development view showing a tread pattern of a pneumatic tire according to one embodiment; [Figure 2] FIG. 2 is an enlarged plan view of a main portion of the tread pattern of FIG. 1. [Figure 3] Cross-sectional view of line III-III in Figure 2. [Figure 4] 1 is an enlarged perspective view showing a main part of a pneumatic tire according to an embodiment. [Figure 5] FIG. 2 is an enlarged plan view of a main portion of the tread pattern of FIG. 1. [Figure 6] Cross-sectional view taken along line VI-VI in Figure 5. [Figure 7] FIG. 10 is an enlarged plan view of a main portion of a tread pattern according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0010] A tire according to one embodiment is a pneumatic tire including a pair of left and right bead portions and sidewalls, and a tread provided between the left and right sidewalls to connect the radially outer ends of the left and right sidewalls. The internal structure of the tire is not particularly limited, and may include, for example, an annular bead core embedded in the bead, a carcass ply having a radial structure extending toroidally between the pair of beads, and a belt and tread rubber provided in the tread on the tire radially outer side of the carcass ply. In this embodiment, a typical tire structure can be adopted except for the tread pattern.

[0011] Unless otherwise specified, the shapes and dimensions in this specification are those of a tire mounted on a standard rim and inflated to standard internal pressure under normal no-load conditions. A standard rim is a "standard rim" in the JATMA standard, a "design rim" in the TRA standard, or a "measuring rim" in the ETRTO standard. Standard internal pressure is the "maximum air pressure" in the JATMA standard, the "maximum value" listed in "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" in the TRA standard, or the "inflation pressure" in the ETRTO standard.

[0012] (1) Basic structure of Tread 10 Figure 1 is a partial development view of a tire tread 10 according to one embodiment. In the drawing, the symbol CL indicates the tire equatorial plane, which corresponds to the tire widthwise center. The symbol W indicates the tire width direction (also referred to as the tire axial direction), with the inner side in the tire width direction W referring to the direction approaching the tire equatorial plane CL and the outer side in the tire width direction W referring to the direction away from the tire equatorial plane CL. The symbol C indicates the tire circumferential direction, which is the direction on the circumference centered on the tire rotation axis.

[0013] The tire shown in Fig. 1 is a tire that has a designated front and back when mounted on a vehicle, that is, the side that is mounted on the outside and the side that is mounted on the inside when mounted on a vehicle are designated. Therefore, a marking for designating the mounting orientation on a vehicle is provided on, for example, the sidewall surface of the tire. In Fig. 1, the tire is mounted on a vehicle so that the side indicated by the symbol OUT faces outward (outside of the vehicle) when mounted on the vehicle, and the side indicated by the symbol IN faces inward (inside of the vehicle) when mounted on the vehicle.

[0014] As shown in FIG. 1, the surface of the tread 10 is provided with main grooves 12A, 12B, 12C, and 12D extending in the tire circumferential direction C, lateral grooves 14A, 14B, 14C, 14D, 14E, 14F, 14G, and 14H extending in the tire width direction W, and blocks 16A, 16B, 16C, 16D, and 16E.

[0015] In detail, the tread 10 has four grooves: a pair of central main grooves 12A, 12B arranged on both sides of the tire equatorial plane CL, and a pair of shoulder main grooves 12C, 12D arranged respectively on the outer side of the pair of central main grooves 12A, 12B in the tire width direction.

[0016] In this embodiment, the inner central main groove 12A on the vehicle inner side IN, the inner shoulder main groove 12C on the vehicle inner side IN, and the outer shoulder main groove 12D on the vehicle outer side OUT extend in an approximately straight line in the tire circumferential direction C, and the outer central main groove 12B on the vehicle outer side OUT extends in the tire circumferential direction C in a zigzag manner while bending.

[0017] The inboard center main groove 12A, inboard shoulder main groove 12C, and outboard shoulder main groove 12D may be zigzag main grooves, and the outboard center main groove 12B may be a straight main groove. That is, as long as the main grooves 12A, 12B, 12C, and 12D extend in the tire circumferential direction C, they do not necessarily have to be parallel to the tire circumferential direction C, and may extend in the tire circumferential direction C at an angle.

[0018] A central block row 18A is provided between the inner central main groove 12A and the outer central main groove 12B. The central block row 18A includes a plurality of central blocks 16A separated in the tire circumferential direction C by first central lateral grooves 14A. The central lateral grooves 14A extend at an angle with respect to the tire width direction W and open to the inner central main groove 12A and the outer central main groove 12B.

[0019] The central block 16A is provided with second central lateral grooves 14B that are inclined in the opposite direction to the first central lateral grooves 14A. One end of the second central lateral groove 14B opens into the inner central main groove 12A and the other end terminates within the central block 16A. The first central lateral grooves 14A and the second central lateral grooves 14B are provided alternately in the tire circumferential direction C. Note that the first central lateral grooves 14A and the second central lateral grooves 14B may be straight, curved, or have bent portions, as long as they extend at an angle with respect to the tire width direction W.

[0020] An inner intermediate block row 18B is provided between the inner center main groove 12A and the inner shoulder main groove 12C. The inner intermediate block row 18B includes a plurality of inner intermediate blocks 16B separated in the tire circumferential direction C by inner intermediate lateral grooves 14C.

[0021] The inner intermediate lateral grooves 14C extend at an angle with respect to the tire width direction W and open to the inner central main groove 12A and the inner shoulder main groove 12C. The inner intermediate lateral grooves 14C are arranged alternately in the tire circumferential direction C. The inner intermediate lateral grooves 14C are straight grooves. Note that the inner intermediate lateral grooves 14C may be straight, curved, or have a bent portion, as long as they extend at an angle with respect to the tire width direction W.

[0022] Because the inner intermediate lateral grooves 14C extend at an angle relative to the tire width direction W, the inner intermediate blocks 16B have acute angle portions 16B1 and obtuse angle portions 16B2. The acute angle portions 16B1 are corners formed when the inner intermediate lateral grooves 14C intersect with the inner shoulder main grooves 12C at an acute angle. The obtuse angle portions 16B2 are corners formed when the inner intermediate lateral grooves 14C intersect with the inner shoulder main grooves 12C at an obtuse angle. The acute angle portions 16B1 and the obtuse angle portions 16B2 are alternately provided in the tire circumferential direction C.

[0023] An inner shoulder block row 18C is provided on the outer side of the inner shoulder main groove 12C in the tire width direction (i.e., between the inner shoulder main groove 12C and the ground contact edge). The inner shoulder block row 18C includes a plurality of inner shoulder blocks 16C separated in the tire circumferential direction C by inner shoulder lateral grooves 14D.

[0024] The inner shoulder lateral grooves 14D extend at an angle relative to the tire width direction W and open to the inner shoulder main groove 12C and the tread edge. The openings of the inner shoulder lateral grooves 14D that open to the inner shoulder main groove 12C are formed on an extension of the inner intermediate lateral grooves 14C. The inner shoulder lateral grooves 14D are grooves that have a bent portion. Note that the inner shoulder lateral grooves 14D may be straight, curved, or have a bent portion, as long as they extend at an angle relative to the tire width direction W.

[0025] Because the inner shoulder lateral groove 14D extends at an angle relative to the tire width direction W, the inner shoulder block 16C has an acute-angle portion 16C1 and an obtuse-angle portion 16C2. The acute-angle portion 16C1 is a corner formed when the inner shoulder lateral groove 14D intersects with the inner shoulder main groove 12C at an acute angle. The obtuse-angle portion 16C2 is a corner formed when the inner shoulder lateral groove 14D intersects with the inner shoulder main groove 12C at an obtuse angle.

[0026] Like the acute angle portions 16B1 and obtuse angle portions 16B2 of the inner intermediate blocks 16B, the acute angle portions 16C1 and obtuse angle portions 16C2 of the inner shoulder blocks 16C are alternately arranged in the tire circumferential direction C. The acute angle portions 16C1 of the inner shoulder blocks 16C face the obtuse angle portions 16B2 of the inner intermediate blocks 16B in the extension direction of the inner intermediate lateral grooves 14C. The obtuse angle portions 16C2 of the inner shoulder blocks 16C face the acute angle portions 16B1 of the inner intermediate blocks 16B in the extension direction of the inner intermediate lateral grooves 14C.

[0027] An outer intermediate block row 18D is provided between the outer center main groove 12B and the outer shoulder main groove 12D. The outer intermediate block row 18D includes a plurality of outer intermediate blocks 16D separated in the tire circumferential direction C by first outer intermediate lateral grooves 14E. The first outer intermediate lateral grooves 14E extend obliquely with respect to the tire width direction W and open to the outer center main groove 12B and the outer shoulder main grooves 12D.

[0028] The outer intermediate block 16D is provided with a second outer intermediate lateral groove 14F that is inclined in the opposite direction to the first outer intermediate lateral groove 14E. The second outer intermediate lateral groove 14F has one end that opens into the outer shoulder main groove 12D and the other end that terminates within the outer intermediate block 16D. The first outer intermediate lateral groove 14E and the second outer intermediate lateral groove 14F are alternately provided in the tire circumferential direction C. The first outer intermediate lateral groove 14E and the second outer intermediate lateral groove 14F may be straight, curved, or have a bent portion, as long as they extend at an angle with respect to the tire width direction W. Alternatively, the second outer intermediate lateral groove 14F may have one end that opens into the outer shoulder main groove 12D and the other end that opens into the outer central main groove 12B, as shown in FIG. 7 .

[0029] An outer shoulder block row 18E is provided on the outer side of the outer shoulder main groove 12D in the tire width direction (i.e., between the outer shoulder main groove 12D and the ground contact edge). The outer shoulder block row 18E includes a plurality of outer shoulder blocks 16E separated in the tire circumferential direction C by first outer shoulder lateral grooves 14G. The first outer shoulder lateral grooves 14G extend at an angle with respect to the tire width direction W and open to the outer shoulder main groove 12D and the ground contact edge.

[0030] The outer shoulder block 16E is provided with a second outer shoulder lateral groove 14H extending parallel to the first outer shoulder lateral groove 14G. The second outer shoulder lateral groove 14H is a groove that opens at one end to the ground contact edge and terminates at the other end within the outer shoulder block 16E. The first outer shoulder lateral groove 14G and the second outer shoulder lateral groove 14H are provided alternately in the tire circumferential direction C. Note that the first outer shoulder lateral groove 14G and the second outer shoulder lateral groove 14H may be straight, curved, or have a bent portion, as long as they extend at an angle with respect to the tire width direction W.

[0031] (2) Inner intermediate block 16B and inner shoulder block 16C Next, the inner intermediate block 16B and the inner shoulder block 16C will be described. As shown in Figures 1 and 2, the inner intermediate block 16B and the inner shoulder block 16C are provided with reinforcing protrusions 20, 22, respectively.

[0032] The reinforcing projection 20 protrudes from the acute angle side of the sidewall 16B3 of the inner intermediate block 16B facing the shoulder main groove 12C toward the center of the shoulder main groove 12C (toward the sidewall 16B3 of the inner shoulder block 16C facing the sidewall 16B3). As shown in Fig. 3, the reinforcing projection 20 is provided from the tread surface 16B4 of the inner intermediate block 16B to the groove bottom 12C1 of the shoulder main groove 12C.

[0033] As shown in Figure 3, the reinforcing protrusion 20 has a tread side inclined surface 20a that is connected to the tread surface 16B4 of the inner intermediate block 16B and extends toward the groove bottom 12C1 side, and a groove bottom side inclined surface 20b that is connected to the tread side inclined surface 20a and further extends toward the groove bottom 12C1 side.

[0034] The tread-side inclined surface 20a is inclined relative to the tire radial direction. The groove-bottom-side inclined surface 20b is provided substantially parallel to the tire radial direction. That is, the inclination angle θ1 of the tread-side inclined surface 20a relative to the tire radial direction is larger than the inclination angle of the groove-bottom-side inclined surface 20b relative to the tire radial direction. θ1 is, for example, 25° or more and 65° or less.

[0035] In addition, the groove bottom side inclined surface 20b may be inclined with respect to the tire radial direction as long as the inclination angle with respect to the tire radial direction is smaller than the inclination angle θ1 of the tread side inclined surface 20a. For example, the inclination angle of the groove bottom side inclined surface 20b with respect to the tire radial direction can be 10° or less.

[0036] A curved surface that smoothly connects the groove bottom side inclined surface 20b and the groove bottom 12C1 is provided on the groove bottom 12C1 side of the groove bottom side inclined surface 20b.

[0037] The reinforcing protrusions 22 protrude from the acute angle side of the sidewall 16C3 of the inner shoulder block 16C facing the shoulder main groove 12C toward the center of the inner shoulder main groove 12C (toward the sidewall 16B3 of the inner intermediate block 16B). The reinforcing protrusions 22 are provided from the tread surface 16C4 of the inner shoulder block 16C to the groove bottom 12C1 of the shoulder main groove 12C. These reinforcing protrusions 22 and the reinforcing protrusions 20 provided on the inner shoulder block 16C are arranged alternately in the tire circumferential direction C (see FIGS. 1 and 2).

[0038] The reinforcing protrusion 22 has a tread side inclined surface 22a that is connected to the tread surface 16C4 of the inner shoulder block 16C and extends toward the groove bottom 12C1 side, and a groove bottom side inclined surface 22b that is connected to the tread side inclined surface 22a and further extends toward the groove bottom 12C1 side.

[0039] The tread-side inclined surface 22a is inclined relative to the tire radial direction. The groove-bottom-side inclined surface 22b is provided substantially parallel to the tire radial direction. That is, the inclination angle θ2 of the tread-side inclined surface 22a relative to the tire radial direction is larger than the inclination angle of the groove-bottom-side inclined surface 22b relative to the tire radial direction. θ2 is, for example, 25° or more and 65° or less.

[0040] In addition, the groove bottom side inclined surface 22b may be inclined with respect to the tire radial direction as long as the inclination angle with respect to the tire radial direction is smaller than the inclination angle θ2 of the tread side inclined surface 22a. For example, the inclination angle of the groove bottom side inclined surface 22b with respect to the tire radial direction can be 10° or less.

[0041] A curved surface that smoothly connects the groove bottom side inclined surface 22b and the groove bottom 12C1 is provided on the groove bottom 12C1 side of the groove bottom side inclined surface 22b.

[0042] The groove-bottom-side inclined surfaces 20b, 22b of the reinforcing projections 20, 22 preferably have a height H from the groove bottom 12C1 of the inner shoulder main groove 12C that is 50% or more of the depth D0 of the inner shoulder main groove 12C. In other words, the tread-side inclined surfaces 20a, 22a are preferably provided closer to the tread than a position that is 50% of the depth D0 of the inner shoulder main groove 12C. For example, the depth D0 of the inner shoulder main groove 12C may be 5 to 10 cm, the height H of the groove-bottom-side inclined surfaces 20b, 22b may be 5 to 8.5 cm, and the height (length in the tire radial direction) of the tread-side inclined surfaces 20a, 22a may be 1 to 3 cm.

[0043] Sipes may also be provided in the inner intermediate block 16B and the inner shoulder block 16C. In this embodiment, three sipes 24a, 24b, and 24c are provided in the inner intermediate block 16B, and three sipes 24d, 24e, and 24f are provided in the inner shoulder block 16C.

[0044] In this specification, a sipe refers to a cut formed in a block and has a very small groove width. The groove width of a sipe is not particularly limited and may be, for example, 0.1 to 1.5 mm, 0.2 to 1.0 mm, or 0.3 to 0.8 mm. Note that as long as the sipe is a narrow groove extending in the tire width direction W, it does not necessarily have to be parallel to the tire width direction W, and it may be a narrow groove extending in the tire width direction W while being inclined. Furthermore, the sipe may be straight, curved, or have a bent portion.

[0045] As shown in FIGS. 2 and 4, three sipes 24a, 24b, 24c provided in the inner intermediate block 16B extend obliquely with respect to the tire width direction W and open into the inner shoulder main groove 12C.

[0046] Specifically, the sipes 24a are acute-angle-side sipes that open to the reinforcing projections 20. As shown in FIG. 3, the depth D1 of the inner intermediate block acute-angle-side sipes 24a may be the same as or shallower than the depth D0 of the inner shoulder main groove 12C. The depth D1 of the inner intermediate block acute-angle-side sipes 24a may be constant in the direction of extension or may vary in the direction of extension. For example, the depth D1 may be shallower at the end of the opening to the inner shoulder main groove 12C and deeper at the center in the direction of extension.

[0047] The depth D11 at the opening end may be shallower than the lower end position of the tread-side inclined surface 20a (the upper end position of the groove bottom-side inclined surface 20b), and may be, for example, 10% to 90% of the depth D0 of the inner shoulder main groove 12C. Also, the inner intermediate block acute-angle-side sipe 24a may open to the tread-side inclined surface 20a without opening to the groove bottom-side inclined surface 20b.

[0048] Furthermore, the depth D1 at the center of the inner intermediate block acute angle side sipe 24a in the extension direction may be deeper than the lower end position of the tread side inclined surface 20a, and may be, for example, 50% to 90% of the depth D0 of the inner shoulder main groove 12C.

[0049] The sipe 24b is a sipe provided in the center of the inner intermediate block 16B in the tire circumferential direction C, and is an inner intermediate block intermediate sipe 24b that opens at the base of the reinforcing projection 20 that projects from the side wall 16B3 of the inner intermediate block 16B.

[0050] The sipe 24c is an inner intermediate block obtuse angle side sipe 24c that opens on the obtuse angle side of the sidewall 16B3 of the inner intermediate block 16B (that is, at a position facing the reinforcing projection 22 of the inner shoulder block 16C in the tire width direction W).

[0051] The inner intermediate block acute angle-side sipes 24a, inner intermediate block intermediate sipes 24b, and inner intermediate block obtuse angle-side sipes 24c are arranged parallel to the inner intermediate lateral groove 14C, but may be grooves extending at an angle relative to the inner intermediate lateral groove 14C. The inner intermediate block acute angle-side sipes 24a and inner intermediate block obtuse angle-side sipes 24c also open into the inner central main groove 12A and are arranged to completely cross the inner intermediate block 16B, but this is not necessarily the case. The inner intermediate block intermediate sipe 24b does not have to completely cross the inner intermediate block 16B as in the illustrated example, but it may also completely cross it.

[0052] As shown in FIG. 2, three sipes 24d, 24e, 24f provided in the inner shoulder block 16C extend obliquely with respect to the tire width direction W and open into the inner shoulder main groove 12C.

[0053] Specifically, the sipe 24d is an inner shoulder block acute angle side sipe that opens to the reinforcing projection 22. As shown in FIG. 2, the inner shoulder block acute angle side sipe 24d may be provided on an extension of the inner intermediate block obtuse angle side sipe 24c provided in the inner shoulder block 16C.

[0054] The depth D2 of the inner shoulder block acute-angle-side sipe 24d, like the inner intermediate block acute-angle-side sipe 24a provided in the inner intermediate block 16B, may be the same as the depth D0 of the inner shoulder main groove 12C, or it may be shallower. The depth D2 of the inner shoulder block acute-angle-side sipe 24d may be constant in the extension direction or may vary in the extension direction. For example, the depth D2 may be shallower at the opening end to the inner shoulder main groove 12C and deeper in the center in the extension direction.

[0055] The depth D21 at the opening end may be shallower than the lower end position of the tread-side inclined surface 22a (the upper end position of the groove bottom-side inclined surface 22b), and may be, for example, 10% to 90% of the depth D0 of the inner shoulder main groove 12C. Also, the inner shoulder block acute-angle-side sipe 24d may open to the tread-side inclined surface 22a without opening to the groove bottom-side inclined surface 22b.

[0056] The depth D2 at the center of the inner shoulder block acute angle side sipe 24d in the extension direction may be deeper than the lower end position of the tread side inclined surface 22a, and may be, for example, 50% to 90% of the depth D0 of the inner shoulder main groove 12C.

[0057] The sipe 24e is a sipe provided in the center of the inner shoulder block 16C in the tire circumferential direction C, and is a root sipe that opens at the root of the reinforcing projection 22 protruding from the sidewall 16C3 of the inner shoulder block 16C. As shown in FIG. 2, the inner shoulder block intermediate sipe 24e may be provided on an extension of the inner intermediate block intermediate sipe 24b provided in the inner shoulder block 16C.

[0058] The sipes 24f are inner shoulder block obtuse-angle side sipes 24f that open on the obtuse-angle side of the sidewall 16C3 of the inner shoulder block 16C (i.e., at positions facing the reinforcing projections 20 of the inner intermediate block 16B in the tire width direction W). As shown in FIG. 2, the inner shoulder block acute-angle side sipes 24d may be provided on an extension of the inner intermediate block obtuse-angle side sipes 24c provided on the inner shoulder block 16C.

[0059] The inner shoulder block acute angle side sipes 24d, the inner shoulder block intermediate sipes 24e, and the inner shoulder block obtuse angle side sipes 24f are arranged parallel to the inner shoulder lateral groove 14D, but may also be grooves that extend at an angle relative to the inner shoulder lateral groove 14D.

[0060] (3) Central block 16A and outer intermediate block 16D Next, the central block 16A and the outer intermediate block 16D will be described. As shown in Figures 1 and 5, the central block 16A and the outer intermediate block 16D are each provided with a plurality of sipes extending at an angle with respect to the tire width direction W and connecting portions that connect the sipes.

[0061] Specifically, the outer intermediate block 16D is provided with a first intermediate sipe 24g, a second intermediate sipe 24h, a third intermediate sipe 24i, a fourth intermediate sipe 24j, a first intermediate connecting portion 26a, and a second intermediate connecting portion 26b.

[0062] 5, the first intermediate sipe 24g extends at an incline opposite to the first outer intermediate lateral groove 14E with respect to the tire width direction W. One end 24g1 of the first intermediate sipe 24g is connected to the first intermediate connecting portion 26a provided in the outer intermediate block 16D, and the other end opens to the side wall 16D1 of the outer intermediate block 16D facing the first outer intermediate lateral groove 14E.

[0063] The second intermediate sipes 24h extend at an incline opposite to that of the second outer intermediate lateral grooves 14F with respect to the tire width direction W. That is, the second intermediate sipes 24h extend at an incline opposite to that of the first intermediate sipes 24g with respect to the tire width direction W. One end 24h1 of the second intermediate sipes 24h is disposed at a position shifted in the tire circumferential direction C from one end 24g1 of the first intermediate sipes 24g and is connected to a first intermediate connecting portion 26a provided on the outer intermediate block 16D. The other end of the second intermediate sipe 24h opens to a sidewall 16D2 of the outer intermediate block 16D facing the second outer intermediate lateral groove 14F.

[0064] The third intermediate sipes 24i extend inclined in the opposite direction to the second outer intermediate lateral grooves 14F with respect to the tire width direction W. One end 24i1 of the third intermediate sipes 24i is connected to a second intermediate connecting portion 26b provided in the outer intermediate block 16D. The other end of the third intermediate sipes 24i opens to a sidewall 16D3 of the outer intermediate block 16D facing the outer central main groove 12B. As shown in FIG. 7, the second outer intermediate lateral groove 14F may be provided to penetrate the outer intermediate block 16D, and the other end of the third intermediate sipes 24i may open to a sidewall 16D2 of the outer intermediate block 16D facing the second outer intermediate lateral groove 14F.

[0065] The fourth intermediate sipes 24j extend at an incline opposite to that of the first outer intermediate lateral groove 14E with respect to the tire width direction W. That is, the fourth intermediate sipes 24j extend at an incline opposite to that of the third intermediate sipes 24i with respect to the tire width direction W. One end 24j1 of the fourth intermediate sipes 24j is disposed at a position shifted in the tire circumferential direction C from one end 24i1 of the third intermediate sipes 24i and is connected to the second intermediate connecting portion 26b provided on the outer intermediate block 16D. The other end of the fourth intermediate sipe 24j opens to the sidewall 16D1 of the outer intermediate block 16D facing the first outer intermediate lateral groove 14E.

[0066] The first intermediate connecting portion 26a is a recess recessed from the tread surface of the outer intermediate block 16D and has a trapezoidal shape in a plan view as shown in Fig. 5. The first intermediate connecting portion 26a connects one ends 24g1 and 24h1 of the first intermediate sipe 24g and the second intermediate sipe 24h that are arranged apart in the tire circumferential direction C.

[0067] 6, the depth of the first intermediate connecting portion 26a is shallower than the depths of the first intermediate sipes 24g and the second intermediate sipes 24h. For example, the depth of the first intermediate connecting portion 26a may be 1.0 to 4.0 mm. The first intermediate connecting portion 26a has an inclined bottom surface 26a1 that becomes deeper as it approaches the tips of the first intermediate sipes 24g and the second intermediate sipes 24h (as it approaches the inner side in the tire width direction W).

[0068] Similar to the first intermediate connecting portion 26a, the second intermediate connecting portion 26b is formed as a recess recessed from the tread surface of the outer intermediate block 16D and has a trapezoidal shape in a plan view as shown in Fig. 5. The second intermediate connecting portion 26b connects one ends 24i1, 24j1 of the third intermediate sipe 24i and the fourth intermediate sipe 24j that are arranged apart in the tire circumferential direction C.

[0069] The depth of the second intermediate connecting portion 26b is shallower than the depth of the third intermediate sipes 24i and the fourth intermediate sipes 24j. For example, the depth of the second intermediate connecting portion 26b may be 1.0 to 4.0 mm. The second intermediate connecting portion 26b has an inclined bottom surface 26b1 that becomes deeper as it approaches the tips of the third intermediate sipes 24i and the fourth intermediate sipes 24j (as it approaches the inner side in the tire width direction W).

[0070] The first intermediate connecting portions 26a and the second intermediate connecting portions 26b are arranged to be offset in the tire width direction W and alternately arranged in the tire circumferential direction C.

[0071] In this embodiment, the central block 16A is provided with a first central sipe 24k, a second central sipe 24l, a third central sipe 24m, a fourth central sipe 24n, a first central connecting portion 28a, and a second central connecting portion 28b.

[0072] 5, the first central sipe 24k extends at an incline opposite to the first central lateral groove 14A with respect to the tire width direction W. One end 24k1 of the first central sipe 24k is connected to the first central connecting portion 28a provided in the central block 16A, and the other end opens to the sidewall 16A1 of the central block 16A facing the outer central main groove 12B.

[0073] The second central sipes 24l extend at an incline opposite to that of the second central lateral grooves 14B with respect to the tire width direction W. That is, the second central sipes 24l extend at an incline opposite to that of the first central sipes 24k with respect to the tire width direction W. One end 24l1 of the second central sipes 24l is positioned offset in the tire circumferential direction C from one end 24k1 of the first central sipes 24k and is connected to a first central connecting portion 28a provided on the central block 16A. The other end of the second central sipe 24l opens to the sidewall 16A1 of the central block 16A facing the outer central main groove 12B.

[0074] The third central sipe 24m extends at an incline opposite to the second central lateral groove 14B with respect to the tire width direction W. One end 24m1 of the third central sipe 24m is connected to the second central connecting portion 28b provided in the outer intermediate block 16D. The other end 24m of the third central sipe 24m opens to the sidewall 16A2 of the central block 16A facing the inner central main groove 12A.

[0075] The fourth central sipe 24n extends at an incline opposite to that of the first central lateral groove 14A with respect to the tire width direction W. That is, the fourth central sipe 24n extends at an incline opposite to that of the third central sipe 24m with respect to the tire width direction W. One end 24n1 of the fourth central sipe 24n is positioned offset in the tire circumferential direction C from one end 24m1 of the third central sipe 24m and is connected to the second central connecting portion 28b provided on the central block 16A. The other end of the fourth central sipe 24n opens to the sidewall 16A2 of the central block 16A facing the inboard central main groove 12A.

[0076] The first central connecting portion 28a is a recess recessed from the tread surface of the central block 16A and has a trapezoidal shape in a plan view as shown in Fig. 5. The first central connecting portion 28a connects one end 24k1, 24l1 of the first central sipe 24k and the second central sipe 24l that are spaced apart in the tire circumferential direction C.

[0077] 6, the depth of the first central connecting portion 28a is shallower than the depths of the first central sipes 24k and the second central sipes 24l. For example, the depth of the first central connecting portion 28a may be 1.0 to 4.0 mm. The first central connecting portion 28a has an inclined bottom surface 28a1 that becomes deeper as it approaches the tips of the first central sipes 24k and the second central sipes 24l.

[0078] The length of the first central coupling portion 28a along the tire circumferential direction C is longer than the length of the first intermediate coupling portion 26a provided in the outer intermediate block 16D along the tire circumferential direction C. For example, the length of the first intermediate coupling portion 26a along the tire circumferential direction C may be 1.0 to 5.0 mm, and the length of the first central coupling portion 28a along the tire circumferential direction C may be 5.0 to 10.0 mm. The first central coupling portion 28a is disposed so as to overlap at least a portion of the first intermediate coupling portion 26a in the tire width direction W.

[0079] Like the first central connecting portion 28a, the second central connecting portion 28b is a recess recessed from the tread surface of the central block 16A and has a trapezoidal shape in a plan view as shown in FIG. 5. The second central connecting portion 28b connects one ends 24m1, 24n1 of the third central sipe 24m and the fourth central sipe 24n, which are spaced apart in the tire circumferential direction C. The depth of the second central connecting portion 28b is shallower than the depths of the third central sipe 24m and the fourth central sipe 24n. For example, the depth of the second central connecting portion 28b may be 1.0 to 4.0 mm. The second central connecting portion 28b has an inclined bottom surface 28b1 that becomes deeper as it approaches the tips of the third central sipe 24m and the fourth central sipe 24n (as it approaches the inner side in the tire width direction W).

[0080] The second central connecting portion 28b is disposed so as to overlap at least a portion of the second intermediate connecting portion 26b in the tire width direction W.

[0081] In this embodiment, the first intermediate sipes 24g and the fourth intermediate sipes 24j are arranged parallel to the second outer intermediate lateral groove 14F, and the second intermediate sipes 24h and the third intermediate sipes 24i are arranged parallel to the first outer intermediate lateral groove 14E.

[0082] The first central sipe 24k and the fourth central sipe 24n are arranged parallel to the second central lateral groove 14B, and are also parallel to the first intermediate sipe 24g, the fourth intermediate sipe 24j, and the second outer intermediate lateral groove 14F. The second central sipe 24l and the third central sipe 24m are arranged parallel to the first central lateral groove 14A, and are also parallel to the second intermediate sipe 24h, the third intermediate sipe 24i, and the first outer intermediate lateral groove 14E.

[0083] (4) Effects In the pneumatic tire of this embodiment as described above, the outer intermediate block 16D and the center block 16A are Because a pair of sipes connected by a connecting portion are inclined in opposite directions relative to the tire width direction W, when a large force is applied during cornering, at least one of the pair of sipes forms a large angle close to perpendicular to the direction of travel of the vehicle. This allows the edge effect of the sipes to be maintained in the outer intermediate block 16D and the center block 16A not only during straight driving but also during cornering.

[0084] Furthermore, the sipes that are inclined in the opposite direction to the tire width direction W are connected by connecting portions 26a, 26b, 28a, 28b that are shallower recesses than these sipes, which reduces distortion and heat generation at the ends of the sipes and improves durability, while also preventing a decrease in rigidity of the outer intermediate block 16D and the central block 16A and suppressing uneven wear.

[0085] In this embodiment, the connecting portions 26a, 26b, 28a, and 28b have inclined bottom surfaces 26a1, 26b1, 28a1, and 28b1 that become deeper as they approach the tips of the sipes, thereby efficiently suppressing distortion and heat generation at the ends of the sipes.

[0086] In this embodiment, the first intermediate sipes 24g extend at an incline opposite to the first outer intermediate lateral groove 14E with respect to the tire width direction W and open to the side wall 16D1 of the outer intermediate block 16D facing the first outer intermediate lateral groove 14E, and the second intermediate sipes 24h extend at an incline opposite to the second outer intermediate lateral groove 14F with respect to the tire width direction W and open to the side wall 16D2 of the outer intermediate block 16D facing the second outer intermediate lateral groove 14F, so that block rigidity can be ensured when the vehicle corners and uneven wear can be suppressed.

[0087] In particular, in this embodiment, the first intermediate sipes 24g are arranged parallel to the second outer intermediate lateral grooves 14F, and the second intermediate sipes 24h are arranged parallel to the first outer intermediate lateral grooves 14E. Therefore, when a force acts on the outer intermediate blocks 16D to tilt toward the first outer intermediate lateral grooves 14E or the second outer intermediate lateral grooves 14F, the groove widths of the second intermediate sipes 24h and the first intermediate sipes 24g arranged parallel to each other widen, making it easier to exhibit the edge effect, thereby improving performance on slippery road surfaces such as icy and snowy roads.

[0088] Furthermore, in the vehicle mounting position, the outer region OUT of the tire on the outer side of the vehicle from the tire equatorial plane CL is prone to large forces acting when the vehicle turns. However, in this embodiment, the first intermediate sipe 24g, second intermediate sipe 24h, third intermediate sipe 24i, fourth intermediate sipe 24j, first intermediate connecting portion 26a and second intermediate connecting portion 26b as described above are provided in the outer region, so that the outer intermediate block 16D is less likely to collapse, and uneven wear can be suppressed.

[0089] Furthermore, sipes 24a, 24b, 24c, 24d, 24e, and 24f parallel to the inner intermediate lateral grooves 14C and the inner shoulder lateral grooves 14D are provided in the inner intermediate blocks 16B and the inner shoulder blocks 16C, which are located in the inner region on the vehicle's inner side IN of the tire equatorial plane CL when the tire is mounted on the vehicle. This makes it easy for the groove width of the sipes to widen when the tire is in contact with the ground, thereby achieving a high edge effect.

[0090] The present invention is not limited to the above-described embodiment, and various improvements and modifications can be made without departing from the spirit of the present invention. [Explanation of symbols]

[0091] 10...tread, 12A...inner center main groove, 12B...outer center main groove, 12C...inner shoulder main groove, 12C1...groove bottom, 12D...outer shoulder main groove, 14A...first center lateral groove, 14B...second center lateral groove, 14C...inner intermediate lateral groove, 14D...inner shoulder lateral groove, 14E...first outer intermediate lateral groove, 14F...second outer intermediate lateral groove, 14G...first outer shoulder lateral groove, 14H...second outer shoulder lateral groove, 16A...center block block, 16B...inner intermediate block, 16B1...acute angle portion, 16B2...obtuse angle portion, 16B3...side wall, 16B4...tread surface, 16C...inner shoulder block, 16C1...acute angle portion, 16C2...obtuse angle portion, 16C3...side wall, 16D...outer intermediate block, 16E...outer shoulder block, 18A...center block row, 18B...inner intermediate block row, 18C...inner shoulder block row, 18D...outer intermediate block row, 18 E...outer shoulder block row, 20...reinforcing protrusion, 20a...tread side inclined surface, 20b...groove bottom side inclined surface, 22...reinforcing protrusion, 22a...tread side inclined surface, 22b...groove bottom side inclined surface, 24a...inner intermediate block acute angle side sipe, 24b...inner intermediate block intermediate sipe, 24c...inner intermediate block obtuse angle side sipe, 24d...inner shoulder block acute angle side sipe, 24e...inner shoulder block intermediate sipe, 24f...inner Side shoulder block obtuse angle side sipe, 24g...first intermediate sipe, 24h...second intermediate sipe, 24i...third intermediate sipe, 24j...fourth intermediate sipe, 24k...first central sipe, 24l...second central sipe, 24m...third central sipe, 24n...fourth central sipe, 26a...first intermediate connecting portion, 26b...second intermediate connecting portion, 28a...first central connecting portion, 28a1...inclined bottom surface, 28b...second central connecting portion, 28b1...inclined bottom surface

Claims

1. A pneumatic tire having a tread including a plurality of main grooves extending in the tire circumferential direction, a plurality of lateral grooves spaced apart in the tire circumferential direction, and a first block row in which a plurality of first blocks partitioned by the main grooves and the lateral grooves are arranged in the tire circumferential direction, the plurality of lateral grooves include first lateral grooves extending at an incline with respect to the tire width direction and second lateral grooves inclined in an opposite direction to the first lateral grooves with respect to the tire width direction, and the first lateral grooves and the second lateral grooves are arranged alternately, the first block includes a first sipe extending at an angle with respect to the tire width direction, a second sipe inclined in a direction opposite to the first sipe with respect to the tire width direction, and a first connecting portion connecting end portions of the first sipe and the second sipe, the first connecting portion is a recessed portion shallower than the first sipe and the second sipe; The pneumatic tire includes an inclined surface in which the first connecting portion is inclined toward the tip of the first sipe and the tip of the second sipe.

2. A pneumatic tire having a tread including a plurality of main grooves extending in the tire circumferential direction, a plurality of lateral grooves spaced apart in the tire circumferential direction, and a first block row in which a plurality of first blocks partitioned by the main grooves and the lateral grooves are arranged in the tire circumferential direction, the plurality of lateral grooves include first lateral grooves extending at an incline with respect to the tire width direction and second lateral grooves inclined in an opposite direction to the first lateral grooves with respect to the tire width direction, and the first lateral grooves and the second lateral grooves are arranged alternately, the first block includes a first sipe extending at an angle with respect to the tire width direction, a second sipe inclined in a direction opposite to the first sipe with respect to the tire width direction, and a first connecting portion connecting end portions of the first sipe and the second sipe, the first connecting portion is a recessed portion shallower than the first sipe and the second sipe; the first sipe extends from the first connecting portion at an angle with respect to the first lateral groove and opens in a side wall of the first block facing the first lateral groove, The second sipe extends from the first connecting portion at an angle with respect to the second lateral groove and opens into a side wall of the first block facing the second lateral groove.

3. The pneumatic tire according to claim 2 , wherein the first sipes extend parallel to the second lateral grooves, and the second sipes are provided parallel to the first lateral grooves.

4. A pneumatic tire having a tread including a plurality of main grooves extending in the tire circumferential direction, a plurality of lateral grooves spaced apart in the tire circumferential direction, and a first block row in which a plurality of first blocks partitioned by the main grooves and the lateral grooves are arranged in the tire circumferential direction, the plurality of lateral grooves include first lateral grooves extending at an incline with respect to the tire width direction and second lateral grooves inclined in an opposite direction to the first lateral grooves with respect to the tire width direction, and the first lateral grooves and the second lateral grooves are arranged alternately, the first block includes a first sipe extending at an angle with respect to the tire width direction, a second sipe inclined in a direction opposite to the first sipe with respect to the tire width direction, and a first connecting portion connecting end portions of the first sipe and the second sipe, the first connecting portion is a recessed portion shallower than the first sipe and the second sipe; The plurality of main grooves include a pair of center main grooves and a pair of shoulder main grooves disposed on the outer sides of the pair of center main grooves in the tire width direction, the first block row is an intermediate block row in which a plurality of intermediate blocks are arranged in the tire circumferential direction between the center main groove and the shoulder main groove, a center block row in which a plurality of center blocks are arranged in the tire circumferential direction is provided between the pair of center main grooves, The center block includes a first center sipe and a second center sipe inclined in opposite directions relative to the tire width direction, and a center connecting portion connecting end portions of the first center sipe and the second center sipe, The center connecting portion has a recessed shape that is shallower than the first center sipe and the second center sipe, and has a length along the tire circumferential direction that is longer than the connecting portion provided in the intermediate block.

5. 5. The pneumatic tire according to claim 1, wherein an orientation of the tire to be mounted on a vehicle is specified, and the first block row is provided in an outer region of the tread that is positioned on an outer side of the tire equatorial plane when mounted on a vehicle.

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