Tire

Abstract

To achieve excellent rolling resistance performance and wet grip performance.SOLUTION: In a tire 1, multiple circumferential grooves 3 are provided at a tread part 2. The circumferential grooves 3 include shoulder circumferential grooves 3A and middle circumferential grooves 3B. A groove depth D2 of the middle circumferential groove 3B is smaller than a groove depth D1 of the shoulder circumferential groove 3A. A groove bottom 5B of the middle circumferential groove 3B is provided with a circumferential sipe 7 and a circumferential widening part 9 extending from the circumferential sipe 7 to the inner side as seen in a tire radial direction.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a tire.

Background Art

[0002] Patent Document 1 below describes a pneumatic tire in which a plurality of rib-shaped land portions are formed by at least four circumferential grooves. The circumferential grooves include an outermost circumferential groove located on the outermost side in the tire width direction and an inner adjacent circumferential groove adjacent to the outermost circumferential groove on the inner side in the tire width direction. Further, the rib-shaped land portion has a protrusion portion that protrudes from its side wall surface and extends in the tread circumferential direction. And the protrusion portion in the inner adjacent circumferential groove is formed at a shallower position closer to the tread surface than the protrusion portion in the outermost circumferential groove. Such a pneumatic tire is said to enhance wet grip performance and suppress an increase in rolling resistance.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, there has been a further demand for improving rolling resistance performance and wet grip performance.

[0005] The present disclosure has been devised in view of the above actual situation, and its main object is to provide a tire having excellent rolling resistance performance and wet grip performance.

Means for Solving the Problems

[0006] The present disclosure relates to a tire having a tread portion, wherein the tread portion is provided with a plurality of circumferential grooves that continuously extend in the tire circumferential direction. The circumferential grooves include a pair of shoulder circumferential grooves and at least one middle circumferential groove disposed between the pair of shoulder circumferential grooves. The groove depth of the middle circumferential groove is smaller than the groove depth of the shoulder circumferential groove. At the groove bottom of the middle circumferential groove, a circumferential sipe extending inward in the tire radial direction from the groove bottom and a circumferential width portion extending inward in the tire radial direction from the circumferential sipe and extending in the tire circumferential direction with a width larger than that of the circumferential sipe are provided.

Advantages of the Invention

[0007] By adopting the above configuration, the tire of the present disclosure has excellent rolling resistance performance and wet grip performance.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0009] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. FIG. 1 is a plan view of the tread portion 2 of the tire 1 of the present embodiment. The tire 1 of the present embodiment is preferably used for a pneumatic tire for heavy loads. However, the present disclosure can also be adopted for a tire 1 for a passenger car or a light truck, or a non-pneumatic tire without air filling.

[0010] As shown in Fig. 1, the tread portion 2 of the present embodiment includes a plurality of circumferential grooves 3 continuously extending in the tire circumferential direction and land portions 4 defined by the circumferential grooves 3. The circumferential grooves 3 of the present embodiment include a pair of shoulder circumferential grooves 3A and at least one middle circumferential groove 3B disposed between the pair of shoulder circumferential grooves 3A. The land portions 4 of the present embodiment include a pair of outer land portions 4A disposed outside the pair of shoulder circumferential grooves 3A in the tire axial direction and two or more inner land portions 4B divided by the middle circumferential groove 3B between the pair of shoulder circumferential grooves 3A. A greater ground pressure acts on the inner land portions 4B during straight running than on the outer land portions 4A.

[0011] Fig. 2 is a cross-sectional view taken along line A-A of Fig. 1. As shown in Fig. 2, the groove depth D2 of the middle circumferential groove 3B is formed smaller than the groove depth D1 of the shoulder circumferential groove 3A. Thereby, the rigidity of the inner land portion 4B adjacent to the middle circumferential groove 3B is maintained high, and the deformation of the inner land portion 4B during tire running is suppressed, so that the rolling resistance performance is improved.

[0012] Fig. 3 is a perspective cross-sectional view of the middle circumferential groove 3B. As shown in Figs. 2 and 3, a circumferential sipe 7 and a circumferential widened portion 9 are provided at the groove bottom 5B of the middle circumferential groove 3B. The circumferential sipe 7 of the present embodiment extends inward in the tire radial direction from the groove bottom 5B. The circumferential widened portion 9 of the present embodiment extends inward in the tire radial direction from the circumferential sipe 7 and extends in the tire circumferential direction with a width w2 larger than that of the circumferential sipe 7. Thereby, it is possible to compensate for the decrease in drainage volume due to the middle circumferential groove 3B having a relatively small groove depth, so that excellent rolling resistance performance and wet grip performance are exhibited. In particular, the circumferential widened portion 9 enhances the wet grip performance at the end of wear when it contacts the road surface. In this specification, a "sipe" is a cut-like body having a width perpendicular to the longitudinal direction of 1.5 mm or less. Also, a "groove" is a groove-like body having a groove width perpendicular to the longitudinal direction exceeding 1.5 mm.

[0013] As shown in FIG. 1, in this embodiment, the tread portion 2 is provided with two middle circumferential grooves 3B. As a result, the inner land portion 4B includes a pair of first inner land portions 11 defined by the shoulder circumferential groove 3A and the middle circumferential groove 3B, and a second inner land portion 12 defined by the two middle circumferential grooves 3B. Note that three or more middle circumferential grooves 3B may be provided.

[0014] The middle circumferential groove 3B is preferably provided, for example, within a range of 35% or less of the tread width TW from the tire equator C toward both sides in the tire axial direction. Thereby, the water film of the land portion 4 near the tire equator C, where drainage is difficult, can be effectively discharged. When two middle circumferential grooves 3B are provided in the tread portion 2, the middle circumferential grooves 3B are preferably provided within a range of 20% or more of the tread width TW from the tire equator C toward both sides in the tire axial direction.

[0015] In this specification, the tread width TW is the distance in the tire axial direction between the tread ends Te in the tire 1 in the normal state.

[0016] The "normal state" means that, in the case of the tire 1 for which various standards are defined, the tire 1 is rim-mounted on a normal rim (not shown) and filled with a normal internal pressure, and moreover, it is in a no-load state. In the case of the tire 1 for which no various standards are defined, the normal state means a standard use state according to the purpose of use of the tire 1, and it means a state where the tire 1 is not mounted on a vehicle and is in a no-load state. In this specification, unless otherwise specified, the dimensions and the like of each part of the tire 1 are values measured in the normal state.

[0017] The "normal rim" is the rim defined for each tire in a standard system including the standard on which the tire is based. For example, in the case of JATMA, it is the "standard rim", in the case of TRA, it is the "Design Rim", and in the case of ETRTO, it is the "Measuring Rim".

[0018] "Normal internal pressure" refers to the air pressure defined for each tire in the standard system including the standards on which the tire is based. For JATMA, it is the "maximum air pressure"; for TRA, it is the maximum value described in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES"; and for ETRTO, it is the "INFLATION PRESSURE".

[0019] In this specification, the tread edge Te is the outermost grounding position in the tire axial direction when the regular load is applied to the tire 1 in the regular state and it is grounded on the plane with a camber angle of 0°.

[0020] The shoulder circumferential groove 3A is preferably provided within a range of 37.5% or less of the tread width TW from the tire equator C to the outside in the tire axial direction. Thereby, the rigidity of the outer land portion 4A is ensured, and the deterioration of the rolling resistance performance is suppressed.

[0021] In this embodiment, the shoulder circumferential groove 3A and the middle circumferential groove 3B extend linearly. Thereby, the drainage resistance is reduced, and the wet grip performance can be improved. The shoulder circumferential groove 3A and the middle circumferential groove 3B have groove edges 8, 8 on both sides extending linearly. Note that the shoulder circumferential groove 3A and the middle circumferential groove 3B may extend, for example, in a wave shape or a zigzag shape.

[0022] Although not particularly limited, the groove width W2 of the middle circumferential groove 3B is preferably 80% or more, more preferably 90% or more, preferably 120% or less, and more preferably 110% or less of the groove width W1 of the shoulder circumferential groove 3A. Also, the groove depth D1 (shown in Figure 2) of the shoulder circumferential groove 3A is, for example, 11.0 to 20.0 mm.

[0023] As shown in FIG. 2, when the groove depth D2 of the middle circumferential groove 3B is excessively smaller than the groove depth D1 of the shoulder circumferential groove 3A, the wet grip performance may deteriorate. For this reason, the groove depth D2 of the middle circumferential groove 3B is desirably 30% or more of the groove depth D1 of the shoulder circumferential groove 3A, more desirably 40% or more, desirably 60% or less, and more desirably 50% or less. The groove depth D2 of the middle circumferential groove 3B is desirably, for example, 3.0 to 12.0 mm.

[0024] In this embodiment, the cross-sectional area A2 of the middle circumferential groove 3B is 20% to 60% of the cross-sectional area A1 of the shoulder circumferential groove 3A. Since the cross-sectional area A2 of the middle circumferential groove 3B is 20% or more of the cross-sectional area A1 of the shoulder circumferential groove 3A, the wet grip performance is ensured. Since the cross-sectional area A2 of the middle circumferential groove 3B is 60% or less of the cross-sectional area A1 of the shoulder circumferential groove 3A, the rigidity of the inner land portion 4B can be ensured to be high. From such a viewpoint, the cross-sectional area A2 of the middle circumferential groove 3B is more desirably 30% or more of the cross-sectional area A1 of the shoulder circumferential groove 3A, and more desirably 50% or less.

[0025] In this embodiment, the circumferential sip 7 is provided only at the groove bottom 5B of the middle circumferential groove 3B. In other words, the circumferential sip 7 and the circumferential widened portion 9 are not provided in the shoulder circumferential groove 3A (the groove bottom 5A of the shoulder circumferential groove 3A). Thereby, the land rigidities of the inner land portion 4B and the outer land portion 4A, on which a relatively large contact pressure acts, are maintained in good balance, and the deterioration of the rolling resistance performance is suppressed.

[0026] As shown in FIG. 3, it is desirable that the depth d1 of the circumferential groove 7 be 0.5 to 2.0 times the depth d2 of the circumferential widened portion 9. Since the depth d1 of the circumferential groove 7 is 0.5 times or more the depth d2 of the circumferential widened portion 9, the rigidity of the inner land portion 4B can be increased while maintaining the groove volume of the circumferential widened portion 9. Since the depth d1 of the circumferential groove 7 is 2.0 times or less the depth d2 of the circumferential widened portion 9, the groove volume of the circumferential widened portion 9 can be increased while maintaining the rigidity of the inner land portion 4B. The depth d1 of the circumferential groove 7 is desirably, for example, 40% to 80% of the groove depth D2 of the middle circumferential groove 3B.

[0027] In the present embodiment, the circumferential groove 7 is provided at a position where it becomes the maximum depth of the groove bottom 5B. Thereby, since the water that has entered the groove smoothly flows to the circumferential widened portion 9, the wet grip performance can be further enhanced. The circumferential groove 7 is provided, for example, on the groove center line 3c of the middle circumferential groove 3B (shown in FIG. 1).

[0028] Although not particularly limited, the width w2 of the circumferential widened portion 9 is desirably 150% or more, more desirably 200% or more, desirably 400% or less, and more desirably 350% or less of the width w1 of the circumferential groove 7.

[0029] The width w2 of the circumferential widened portion 9 is formed, for example, smaller than the groove width W2 of the middle circumferential groove 3B. Thereby, the rigidity of the inner land portion 4B is maintained and the rolling resistance performance is enhanced. If the width w2 of the circumferential widened portion 9 is excessively small, there is a possibility that the effect of improving the wet grip performance becomes small. For this reason, the width w2 of the circumferential widened portion 9 is desirably 20% or more, more desirably 30% or more, desirably 65% or less, and more desirably 55% or less of the groove width W2 of the middle circumferential groove 3B.

[0030] The cross-sectional area A3 of the circumferential widened portion 9 is desirably 8% or more, more desirably 12% or more, desirably 24% or less, and more desirably 20% or less of the cross-sectional area A1 of the shoulder circumferential groove 3A. Thereby, the above-described action is effectively exhibited.

[0031] The cross-section of the circumferential widening portion 9 is elliptical. Thereby, the rigidity of each land portion 4 is maintained high. Note that the shape of the circumferential widening portion 9 is not limited to such a mode, and for example, it may be circular, rectangular, or triangular.

[0032] It is desirable that the groove depth D3 of the middle circumferential groove 3B, the circumferential sipe 7, and the circumferential widening portion 9 combined is larger than the groove depth D1 of the shoulder circumferential groove 3A. Since the groove depth D3 is larger than the groove depth D1 of the shoulder circumferential groove 3A, in particular, the reduction in rigidity of the outer land portion 4A is suppressed, and the balance of rigidity with the inner land portion 4B is maintained, so that the action of suppressing the deterioration of the rolling resistance performance is exhibited.

[0033] As shown in FIG. 1, at least one of the inner land portions 4B is provided with an axial sipe 15 extending in the tire axial direction and an axial widening portion 16 extending radially inward in the tire radius direction from the axial sipe 15 and extending in the tire axial direction with a width w4 larger than that of the axial sipe 15. Such an axial sipe 15 and axial widening portion 16 enhance the wet grip performance. In this specification, the axial sipe 15 and the axial widening portion 16 are collectively referred to as an axial groove portion 17.

[0034] The axial groove portion 17 is provided, for example, in the first inner land portion 11 and the second inner land portion 12. The axial groove portions 17A of the first inner land portion 11 and the axial groove portions 17B of the second inner land portion 12 are arranged side by side in the tire circumferential direction. In this embodiment, the axial groove portion 17 is not provided in the outer land portion 4A.

[0035] Each of the axial groove portions 17A of the pair of first inner land portions 11 is arranged, for example, at the same position in the tire circumferential direction. The axial groove portions 17B of the second inner land portion 12 are shifted by a half pitch in the tire circumferential direction from the axial groove portions 17A of the first inner land portion 11. The arrangement positions of the axial groove portions 17A and the axial groove portions 17B are not limited to such a mode.

[0036] In this embodiment, the axial sipe 15 is continuous with the shoulder circumferential groove 3A or the middle circumferential groove 3B. In other words, the axial groove portion 17 is continuous with the shoulder circumferential groove 3A or the middle circumferential groove 3B. Thereby, the water in the axial groove portion 17 is discharged into the shoulder circumferential groove 3A or the middle circumferential groove 3B, so that the wet grip performance is further enhanced.

[0037] The axial sipe 15 is arranged, for example, at an angle θ1 within 30 degrees with respect to the tire axial direction. In other words, the axial groove portion 17 is arranged at an angle θ1 within 30 degrees with respect to the tire axial direction. Thereby, the rigidity of the inner land portion 4B in the tire axial direction is maintained high, and the rolling resistance performance is improved.

[0038] Although not particularly limited, the width w4 of the axial width portion 16 is preferably 2.0 to 4.0 times the width w3 of the axial sipe 15.

[0039] As shown in FIGS. 2 and 3, the depth d3 of the axial sipe 15 is preferably 90% to 110% of the groove depth D2 of the middle circumferential groove 3B. Thereby, during the initial wear stage when the middle circumferential groove 3B exists from the new state of the tire 1, the reduction in the rigidity of the inner land portion 4B is suppressed by the axial sipe 15, and the wet grip performance is maintained by the middle circumferential groove 3B. For this reason, in this embodiment, the depth d3 of the axial sipe 15 is the same as the groove depth D2 of the middle circumferential groove 3B.

[0040] In this embodiment, the axial width portion 16 is continuous with the circumferential sipe 7 or the shoulder circumferential groove 3A. As shown in FIG. 1, for the axial width portion 16A of the first inner land portion 11, for example, the outer end e1 in the tire axial direction is continuous with the shoulder circumferential groove 3A, and the inner end e2 is continuous with the circumferential sipe 7. For the axial width portion 16B of the second inner land portion 12, both ends thereof are continuous with the circumferential sipe 7.

[0041] As shown in FIG. 2, the depth d4 of the axially widened portion 16 is desirably 90% to 110% of the depth d1 of the circumferential sip 7. Thereby, during the middle wear period from after the middle circumferential groove 3B disappears until the circumferential sip 7 disappears, the rigidity of the inner land portion 4B is maintained high by the circumferential sip 7, and the wet grip performance is enhanced by the axially widened portion 16. For this reason, in this embodiment, the depth d4 of the axially widened portion 16 is the same as the depth d1 of the circumferential sip 7.

[0042] The outer land portion 4A of this embodiment is formed as a plain land portion without sips or grooves. Such an outer land portion 4A has high rigidity and enhances the rolling resistance performance. Note that the outer land portion 4A is not limited to such a mode, and for example, a shoulder cross groove (not shown) with a groove depth of 2 mm or less may be provided.

[0043] As described above, the tire of one embodiment of the present disclosure has been described in detail. However, the present disclosure is not limited to the above specific embodiments and can be implemented in various modes.

Example

[0044] A tire having the basic pattern of FIG. 1 was manufactured. Then, the wet grip performance and rolling resistance performance of each test tire were tested. The common specifications and test methods of each test tire are as follows. Tire size: 315 / 70R22.5 Normal rim: 22.5×9.00 Tire internal pressure: 900 kPa Groove depth D1 of the shoulder circumferential groove: 14.5 mm

[0045] <Rolling resistance performance> The rolling resistance performance was carried out in accordance with ECE R117-02 (ECE Regulation No. 117 Revision 2). The rolling resistance performance was evaluated by running the test tire on the simulated road surface of an indoor drum tester and measuring the rolling resistance at that time. The evaluation was expressed as an index with the rolling resistance value of Comparative Example 1 set to 100. The smaller the numerical value, the better the result. Load: 31.25 kN Running speed: 80 km / h

[0046] <Wet grip performance> The wet grip performance was carried out in accordance with ECE R117-02. The wet grip performance was evaluated by the braking distance when the test tire was mounted on the following vehicle and run on the road surface with the following specifications. The evaluation was expressed as an index with the braking distance of Comparative Example 1 set to 100. The smaller the numerical value, the better the result. Also, the results are shown at the initial stage of wear, the middle stage of wear, and the final stage of wear. Road surface: Asphalt road surface with a water depth of 0.5 - 2.0 mm Vehicle: 10t truck (loaded with 75% of the standard load) Braking distance: The distance from a speed of 65 ± 2 km / h until it stops The test results are shown in Table 1.

[0047]

Table 1

[0048] As a result of the test, it was confirmed that the tires of the examples exhibited excellent rolling resistance performance and wet grip performance.

[0049] [Appendix] The present disclosure includes the following aspects.

[0050] [Disclosure 1] A tire having a tread portion, wherein the tread portion is provided with a plurality of circumferential grooves continuously extending in the circumferential direction of the tire, The circumferential groove includes a pair of shoulder circumferential grooves and at least one middle circumferential groove disposed between the pair of shoulder circumferential grooves, the groove depth of the middle circumferential groove is smaller than the groove depth of the shoulder circumferential groove, at the groove bottom of the middle circumferential groove, a circumferential siped extending inward in the tire radial direction from the groove bottom and a circumferential widened portion extending inward in the tire radial direction from the circumferential siped and extending in the tire circumferential direction with a width larger than that of the circumferential siped are provided, Tire. [Disclosure 2] The circumferential siped is provided only at the groove bottom of the middle circumferential groove. The tire according to Disclosure 1. [Disclosure 3] The middle circumferential groove is provided within a range of 35% or less of the tread width on both sides in the tire axial direction from the tire equator. The tire according to Disclosure 1 or 2. [Disclosure 4] The width of the circumferential widened portion is smaller than the groove width of the middle circumferential groove. The tire according to any one of Disclosures 1 to 3. [Disclosure 5] The cross-sectional area of the middle circumferential groove is 20% to 60% of the cross-sectional area of the shoulder circumferential groove. The tire according to any one of Disclosures 1 to 4. [Disclosure 6] The cross-sectional area of the circumferential widened portion is 8% to 24% of the cross-sectional area of the shoulder circumferential groove. The tire according to any one of Disclosures 1 to 5. [Disclosure 7] The depth of the circumferential siped is 0.5 to 2.0 times the depth of the circumferential widened portion. The tire according to any one of Disclosures 1 to 6. [Disclosure 8] The tread portion includes land portions defined by the circumferential grooves, the land portions include two or more inner land portions divided by the middle circumferential groove between the pair of shoulder circumferential grooves, At least one of the inner land portions is provided with an axial sipe extending in the tire axial direction and an axial widened portion extending radially inward in the tire radius direction from the axial sipe and extending in the tire axial direction with a width larger than that of the axial sipe. The tire according to any one of Disclosures 1 to 7 of the present disclosure. [Disclosure 9] The axial sipe is continuous with the shoulder circumferential groove or the middle circumferential groove. The tire according to Disclosure 8 of the present disclosure. [Disclosure 10] The axial widened portion is continuous with the circumferential sipe or the shoulder circumferential groove. The tire according to Disclosure 8 or 9 of the present disclosure. [Disclosure 11] The depth of the axial sipe is 90% to 110% of the groove depth of the middle circumferential groove. The tire according to any one of Disclosures 8 to 10 of the present disclosure. [Disclosure 12] The depth of the axial widened portion is 90% to 110% of the depth of the circumferential sipe. The tire according to any one of Disclosures 8 to 11 of the present disclosure. [Disclosure 13] The axial sipe is arranged at an angle within 30 degrees with respect to the tire axial direction. The tire according to any one of Disclosures 8 to 12 of the present disclosure.

Description of Signs

[0051] 1 Tire 2 Tread portion 3 Circumferential groove 3A Shoulder circumferential groove 3B Middle circumferential groove 5B Groove bottom 7 Circumferential sipe 9 Circumferential widened portion

Claims

1. A tire having a tread portion, wherein a plurality of circumferential grooves extending continuously in the tire circumferential direction are provided in the tread portion, the circumferential grooves include a pair of shoulder circumferential grooves and at least one middle circumferential groove disposed between the pair of shoulder circumferential grooves, a groove depth of the middle circumferential groove is smaller than a groove depth of the shoulder circumferential groove, a circumferential sipe extending radially inward in the tire radial direction from the groove bottom and a circumferential width portion extending radially inward in the tire radial direction from the circumferential sipe and extending in the tire circumferential direction with a width larger than that of the circumferential sipe are provided at the groove bottom of the middle circumferential groove, a cross-sectional area of the circumferential width portion is 8% to 24% of a cross-sectional area of the shoulder circumferential groove, a tire.

2. The tread portion includes land portions defined by the circumferential grooves, the land portions include two or more inner land portions divided by the middle circumferential groove between the pair of shoulder circumferential grooves, at least one of the inner land portions is provided with an axial sipe extending in the tire axial direction and an axial width portion extending radially inward in the tire radial direction from the axial sipe and extending in the tire axial direction with a width larger than that of the axial sipe. The tire according to claim 1.

3. A depth of the axial width portion is 90% to 110% of a depth of the circumferential sipe. The tire according to claim 2.

4. A tire having a tread portion, wherein a plurality of circumferential grooves extending continuously in the tire circumferential direction are provided in the tread portion, the circumferential grooves include a pair of shoulder circumferential grooves and at least one middle circumferential groove disposed between the pair of shoulder circumferential grooves, a groove depth of the middle circumferential groove is smaller than a groove depth of the shoulder circumferential groove, a circumferential sipe extending radially inward in the tire radial direction from the groove bottom and a circumferential width portion extending radially inward in the tire radial direction from the circumferential sipe and extending in the tire circumferential direction with a width larger than that of the circumferential sipe are provided at the groove bottom of the middle circumferential groove, the tread portion includes land portions defined by the circumferential grooves, the land portions include two or more inner land portions divided by the middle circumferential groove between the pair of shoulder circumferential grooves, At least one of the inner land portions is provided with an axial sipe extending in the tire axial direction and an axial widening portion extending radially inward in the tire radius direction from the axial sipe and extending in the tire axial direction with a width larger than that of the axial sipe. The depth of the axial widening portion is 90% to 110% of the depth of the circumferential sipe. Tire.

5. The tire according to any one of claims 2 to 4, wherein the axial sipe is continuous with the shoulder circumferential groove or the middle circumferential groove.

6. The tire according to any one of claims 2 to 5, wherein the axial widening portion is continuous with the circumferential sipe or the shoulder circumferential groove.

7. The tire according to any one of claims 2 to 6, wherein the depth of the axial sipe is 90% to 110% of the groove depth of the middle circumferential groove.

8. The tire according to any one of claims 2 to 7, wherein the axial sipe is arranged at an angle within 30 degrees with respect to the tire axial direction.

9. The tire according to any one of claims 1 to 8, wherein the circumferential sipe is provided only at the groove bottom of the middle circumferential groove.

10. The tire according to any one of claims 1 to 9, wherein the middle circumferential groove is provided in a range within 35% of the tread width from the tire equator to both sides in the tire axial direction.

11. The tire according to any one of claims 1 to 10, wherein the width of the circumferential widening portion is smaller than the groove width of the middle circumferential groove.

12. The tire according to any one of claims 1 to 11, wherein the cross-sectional area of the middle circumferential groove is 20% to 60% of the cross-sectional area of the shoulder circumferential groove.

13. The tire according to any one of claims 1 to 12, wherein the depth of the circumferential sipe is 0.5 to 2.0 times the depth of the circumferential widening portion.

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