Tire

Abstract

To provide a tire which achieves improvement of steering stability on a dry road surface while maintaining wet performance.SOLUTION: A tire has a tread part 2. The tread part 2 includes a first circumferential groove 11 and a first land part 13. The first land part 13 includes: a contact area 17; a side wall 18 at the first circumferential groove 11 side; and at least one recessed part 20 which is open over the contact area 17 and the side wall 18. In the recessed part 20, an opening is defined by V shaped edges in a tread plan view and a front view of the side wall 18. A maximum length L1 as seen in a tire circumferential direction of the recessed part 20 is 6.0 to 9.0 mm. A maximum depth d1 of the recessed part 20 is 15% to 40% of a maximum depth of the first circumferential groove 11. A maximum length L2 as seen in a tire axial direction of the recessed part 20 is 3.0 to 5.0 times of its depth d1.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a tire.

Background Art

[0002] Patent Document 1 below proposes a tire that improves handling stability on a dry road surface by specifying a main groove that continuously extends in the tire circumferential direction and a lateral groove that extends in the tire axial direction.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, with the improvement of vehicle performance, there has been a demand for further improvement in the handling stability of tires. On the other hand, it is also required to ensure the wet performance of tires.

[0005] In view of the above circumstances, the present disclosure has been devised, and the main problem is to provide a tire that improves handling stability on a dry road surface while maintaining wet performance.

Means for Solving the Problems

[0006] The present disclosure relates to a tire having a tread portion, wherein the tread portion includes a first circumferential groove continuously extending in the tire circumferential direction and a first land portion disposed adjacent to the first circumferential groove. The first land portion includes a ground contact surface, a side wall on the first circumferential groove side, and at least one recess opening across both the ground contact surface and the side wall. The recess defines the opening by a V-shaped edge in a tread plan view and a front view of the side wall, respectively. The maximum length L1 of the recess in the tire circumferential direction is 6.0 to 9.0 mm, the maximum depth d1 of the recess is 15% to 40% of the maximum depth of the first circumferential groove, and the maximum length L2 of the recess in the tire axial direction is 3.0 to 5.0 times the depth d1.

Advantages of the Invention

[0007] By adopting the above configuration, the tire of the present disclosure can improve the handling stability on a dry road surface while maintaining the wet performance.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments 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 meridian cross-sectional view of a tire 1 in a normal state showing an embodiment of the present disclosure. As shown in FIG. 1, the present disclosure is desirably applied to, for example, a pneumatic tire for a passenger car. However, the present disclosure is not limited to such a mode, and the present disclosure may be applied to, for example, tires for motorcycles or heavy loads.

[0010] The "normal state" means that in the case of a pneumatic tire for which various standards are defined, the tire is rim-mounted on a normal rim, filled with a normal internal pressure, and in a no-load state. In the case of a tire for which various standards are not defined, the "normal state" means a standard use state according to the purpose of use of the tire, which is a state of not being mounted on a vehicle and being no-load. In this specification, unless otherwise specified, the dimensions and the like of each part of the tire are values measured in the normal state.

[0011] The "normal rim" is a rim defined for each tire in a standard system including the standards 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".

[0012] The "normal internal pressure" is the air pressure defined for each tire in a standard system including the standards on which the tire is based. In the case of JATMA, it is the "maximum air pressure", in the case of TRA, it is the maximum value described in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES", and in the case of ETRTO, it is the "INFLATION PRESSURE".

[0013] Inside the tire 1 of this embodiment, tire components such as a carcass 6 and a belt layer 7 are arranged. Known modes are appropriately adopted for these tire components.

[0014] The carcass 6 extends from the bead portion 4 on one side, through the sidewall portion 3 on one side, the tread portion 2, and the sidewall portion 3 on the other side, to the bead portion 4 on the other side. The carcass 6 of the present embodiment is composed of, for example, a single carcass ply. The carcass ply is composed of, for example, a carcass cord made of organic fibers arranged at an angle of 75 to 90 degrees with respect to the tire circumferential direction.

[0015] The belt layer 7 is composed of, for example, two belt plies 7A and 7B. The belt plies 7A and 7B are composed of, for example, belt cords arranged at an angle of 10 to 45 degrees with respect to the tire circumferential direction. For the belt cords, for example, organic fiber cords or steel cords can be appropriately adopted. In other embodiments, a tread reinforcement layer such as a band layer may be further arranged outside the belt layer 7.

[0016] In the tread portion 2 of the present embodiment, a plurality of circumferential grooves 8 that continuously extend in the tire circumferential direction are provided. The circumferential grooves 8 provided in the tread portion 2 of the present embodiment include two first circumferential grooves 11 and two second circumferential grooves 12. The first circumferential grooves 11 are respectively provided between the tire equator C and one tread end Te, and between the tire equator C and the other tread end Te. The two second circumferential grooves 12 are provided so as to sandwich the tire equator C between the two first circumferential grooves 11. Thereby, the first circumferential grooves 11 are arranged on the tread end Te side, and the second circumferential grooves 12 are arranged on the inner side in the tire axial direction of the first circumferential grooves 11.

[0017] The tread end Te corresponds to the end of the contact surface when 70% of the normal load is applied to the tire 1 in the normal state and the tread portion 2 is grounded on a plane with a camber angle of 0°.

[0018] For pneumatic tires with various standards defined, the "normal load" is the load defined for each tire in the standard system including the standards on which the tire is based. For JATMA, it is the "maximum load capacity"; for TRA, it is the maximum value described in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES"; for ETRTO, it is the "LOAD CAPACITY". Also, for tires without various standards defined, the "normal load" refers to the maximum applicable load when using the tire, in accordance with the above-mentioned standards.

[0019] The tread portion 2 includes a plurality of land portions 9 divided by a plurality of circumferential grooves 8. The land portions 9 of the present embodiment include a first land portion 13, a second land portion 14, and a third land portion 15. The first land portion 13 is arranged adjacent to the first circumferential groove 11, specifically, it is divided between the first circumferential groove 11 and the second circumferential groove 12. The second land portion 14 is adjacent to the first land portion 13 with the first circumferential groove 11 therebetween. Also, the second land portion 14 is arranged on the outer side in the tire axial direction of the first land portion 13 and includes the tread end Te. The third land portion 15 is divided between two second circumferential grooves 12. It should be noted that the present disclosure is not limited to the above-described aspect as long as the tread portion 2 includes the first circumferential groove 11 and the first land portion 13 arranged adjacent thereto.

[0020] Fig. 2 shows an enlarged plan view of the first land portion 13, the second land portion 14, and the first circumferential groove 11. Fig. 3 shows an enlarged perspective view of the first land portion 13. As shown in Figs. 2 and 3, the first land portion 13 includes a ground contact surface 17, a side wall 18 on the side of the first circumferential groove 11, and at least one recess 20 that opens across both the ground contact surface 17 and the side wall 18.

[0021] As shown in FIG. 3, the recess 20 defines the opening by V-shaped edges in the tread plan view and the front view of the side wall 18, respectively. The edge of the recess 20 corresponds to a ridge line formed by the ground contact surface 17 or the side wall 18 of the first land portion 13 and the inner surface 20i of the recess 20. Since the tire 1 is a rubber product, the ridge line may have a minute width in a cross section perpendicular to its length direction. Further, the ridge line may be microscopically curved in the cross section. The width of the ridge line is desirably 1.0 mm or less, more desirably 0.5 mm or less. When the ridge line has a width, each dimension of the recess 20 described below is measured at the center position of the width of the ridge line.

[0022] As shown in FIG. 2, the maximum length L1 in the tire circumferential direction of the recess 20 is 6.0 to 9.0 mm.

[0023] FIG. 4 shows a cross-sectional view taken along line A-A of FIG. 2. As shown in FIG. 4, the maximum depth d1 of the recess 20 is 15% to 40% of the maximum depth d2 of the first circumferential groove 11. Further, the maximum length L2 in the tire axial direction of the recess 20 is 3.0 to 5.0 times the depth d1.

[0024] By adopting the above-described configuration, the present disclosure can improve the handling stability (hereinafter sometimes simply referred to as "handling stability") on a dry road surface while maintaining wet performance. The reason is presumed to be the following mechanism.

[0025] When the ground contact pressure of the first land portion 13 acts, the recess 20 having the shape and dimensions specified as described above can be appropriately deformed to bring the inner surface 20i of the recess 20 into contact with the ground. Such an action can relieve the excessive ground contact pressure acting on the longitudinal edge 13a of the first land portion 13, suppress problems such as local lifting of the ground contact surface of the first land portion 13, and thus provide a large grip force.

[0026] In addition, while exhibiting the above-described effects, the recess 20 of the present disclosure can maintain the rigidity of the first land portion 13 without excessively reducing the rubber volume of the first land portion 13. Thereby, the handling stability is further improved.

[0027] Further, the recess 20 having the above-described shape and dimensions can efficiently guide the water pushed back by the ground contact surface 17 of the first land portion 13 toward the first circumferential groove 11 side during wet running, and can maintain the wet performance. For such reasons, it is considered that the tire 1 of the present disclosure can improve the handling stability while maintaining the wet performance.

[0028] Hereinafter, a more detailed configuration of the present embodiment will be described. Note that each configuration described below shows a specific aspect of the present embodiment. Therefore, it goes without saying that the present disclosure can exhibit the above-described effects even if it does not have the configurations described below. Further, even if any one of the configurations described below is applied alone to the tire of the present disclosure having the above-described features, an improvement in performance corresponding to each configuration can be expected. Furthermore, when some of the configurations described below are applied in combination, a combined improvement in performance corresponding to each configuration can be expected.

[0029] As shown in FIG. 2, the first land portion 13 of the present embodiment is not provided with a transverse groove that completely crosses the first land portion 13 in the tire axial direction. Thereby, the ground contact surface 17 of the first land portion 13 is continuous in the tire circumferential direction over the entire circumference of the tire. Such a first land portion 13 has high rigidity and can exhibit excellent handling stability.

[0030] In the present embodiment, a plurality of recesses 20 are provided at intervals in the tire circumferential direction in the first land portion 13. The length of one pitch in the tire circumferential direction of the plurality of recesses 20 is, for example, 4.0 to 8.0 times the length L1 in the tire circumferential direction of the recess 20. Such an arrangement of the recesses 20 can improve the handling stability and the wet performance in a well-balanced manner.

[0031] As shown in FIG. 3, it is desirable that the space surrounded by the inner surface 20i of the recess 20, the virtual extension surface of the ground contact surface 17, and the virtual extension surface of the side wall 18 has a triangular pyramid shape. Thereby, when the ground pressure acts on the first land portion 13 and the recess 20 is deformed, the inner surface 20i of the recess 20 easily comes into contact with the ground, and the above-described effects can be surely obtained.

[0032] As shown in FIG. 2, in order to improve the handling stability and wet performance in a well-balanced manner, the length L1 in the tire circumferential direction of the recess 20 is desirably 6.5 mm or more, more desirably 7.0 mm or more, desirably 8.5 mm or less, and more desirably 8.0 mm or less.

[0033] As shown in FIG. 4, from the same viewpoint, the maximum depth d1 of the recess 20 is desirably 25% to 40% of the maximum depth d2 of the first circumferential groove 11, more desirably 35% to 40%. Further, the maximum length L2 in the tire axial direction of the recess 20 is desirably 3.0 to 4.0 times the depth d1, more desirably 3.0 to 3.5 times. However, the present disclosure is not limited to such a range.

[0034] As shown in FIG. 3, it is desirable that the opening area of the recess 20 on the ground contact surface 17 is larger than the opening area of the recess on the side wall 18. Thereby, the inner surface 20i of the recess 20 easily comes into contact with the ground, and excellent handling stability can be obtained.

[0035] As shown in FIG. 2, the angle θ1 between the two edges formed on the ground contact surface 17 of the recess 20 is desirably an acute angle, more desirably 45 to 80°, and further desirably 50 to 70°.

[0036] FIG. 5 shows a side view of the first land portion 13 and the recess 20. As shown in FIG. 5, the angle θ2 between the two edges of the recess 20 formed in the side wall 18 of the first land portion 13 is, for example, larger than the angle θ1. Specifically, the angle θ2 is preferably an obtuse angle, more preferably 110 to 140°, and even more preferably 120 to 130°. Such a recess 20 helps to improve the wet performance while maintaining the rigidity of the first land portion 13.

[0037] As shown in FIG. 3, the inner surface 20i of the recess 20 includes a first inner surface 21 and a second inner surface 22. The first inner surface 21 and the second inner surface 22 are connected via a boundary ridge line 23. The first inner surface 21 is a triangular shape surrounded by an edge 20a on the ground contact surface 17 of the recess 20, an edge 20b on the side wall 18 of the recess 20, and the boundary ridge line 23. Similarly, the second inner surface 22 is also a triangular shape surrounded by an edge 20a on the ground contact surface 17 of the recess 20, an edge 20b on the side wall 18 of the recess 20, and the boundary ridge line 23. The first inner surface 21 and the second inner surface 22 of the present embodiment are each configured to be planar, but may be convexly curved toward the outer side of the tire.

[0038] The boundary ridge line 23 corresponds to the collection of the bottoms of the recess 20 in each cross section when the recess 20 is cut by a virtual plane parallel to the tire circumferential direction. The boundary ridge line 23 extends linearly from the vertex 20c in the tire axial direction of the V-shaped edge formed on the ground contact surface 17 of the recess 20 to the vertex in the tire radial direction of the V-shaped edge formed on the side wall 18 of the recess 20. Also, the depth of the recess 20 continuously increases from the vertex 20c toward the side wall 18. Thereby, the inner surface 20i of the recess 20 is easily grounded, and excellent handling stability is exhibited.

[0039] As shown in FIG. 2, in a tread plan view, the boundary ridge line 23 is preferably inclined with respect to the tire axial direction. The angle θ3 of the boundary ridge line 23 with respect to the tire axial direction is, for example, 20 to 50°, preferably 30 to 40°. Thereby, when a slip angle is applied to the tire 1, the inner surface 20i of the recess 20 is easily grounded, and the handling stability is further improved.

[0040] In another embodiment, for the tire 1 with a specified mounting orientation on the vehicle, it is desirable that the first land portion 13 provided with the above-described recess 20 is located outside the vehicle with respect to the tire equator C when the tire is mounted on the vehicle. Thereby, since the recess 20 is arranged in a region where the change in the ground contact pressure is large, the above-described effects are further exerted.

[0041] In the first land portion 13 of the present embodiment, a plurality of interrupted grooves 25 that extend from the second circumferential groove 12 and are interrupted within the first land portion 13 are provided. Such interrupted grooves 25 can enhance the wet performance while maintaining the rigidity of the first land portion 13.

[0042] From the same viewpoint, it is desirable that the groove width W1 of the interrupted groove 25 is smaller than the circumferential length L1 of the recess 20 in the tire circumferential direction. Specifically, the groove width W1 of the interrupted groove 25 is 70% to 90% of the length L1 of the recess 20. The length L3 of the interrupted groove 25 in the tire axial direction is preferably, for example, 2.0 to 3.5 times the length L2 (shown in FIG. 4) of the recess 20.

[0043] The interrupted groove 25 is preferably inclined slightly with respect to the tire axial direction, for example. The angle θ4 of the interrupted groove 25 with respect to the tire axial direction is, for example, 5 to 20°. In a more desirable embodiment, the angle θ4 of the interrupted groove 25 is smaller than the angle θ3 of the boundary ridge line 23 with respect to the tire axial direction. Such an interrupted groove 25 can moderately relax the circumferential rigidity of the first land portion 13 and can make the inner surface 20i of the recess 20 more easily contact the ground when the ground contact pressure acts on the first land portion 13.

[0044] In order to further enhance the above-described effects, the circumferential distance L4 in the tire circumferential direction from the interrupted end 25a of the interrupted groove 25 within the first land portion 13 to the apex 20c of the V-shaped edge on the ground contact surface 17 of the recess 20 is smaller than the circumferential length L1 of the interrupted groove 25. Specifically, the distance L4 is 20% to 35% of the length L1 of the interrupted groove 25.

[0045] The second land portion 14 is provided with a plurality of transverse grooves 30. The transverse grooves 30 extend, for example, in the tire axial direction from the first circumferential direction groove 11. The transverse grooves 30 of the present embodiment extend from the first circumferential direction groove 11 to a position beyond the tread end Te.

[0046] In the tread plan view, it is desirable that the end portion 30a of the transverse groove 30 on the first circumferential direction groove 11 side faces the recess 20. Thereby, the recess 20 and the transverse groove 30 can cooperate to enhance the wet performance. Note that the end portion 30a facing the recess 20 means that, in the tread plan view, the region where the recess 20 is extended in parallel with the tire axial direction overlaps the opening in the first circumferential direction groove 11 of the transverse groove 30.

[0047] It is desirable that the groove width W2 at the end of the transverse groove 30 is larger than the length L1 of the recess 20. Specifically, the groove width W2 of the transverse groove 30 is 120% - 140% of the length L1 of the recess 20. Such a transverse groove 30 helps to enhance the handling stability and wet performance in a well - balanced manner.

[0048] The transverse grooves 30 are provided, for example, at an angle θ5 of 0 to 10° with respect to the tire axial direction. The angle θ5 of the transverse groove 30 with respect to the tire axial direction is smaller than the angle θ3 of the boundary ridge line 23 with respect to the tire axial direction. Thereby, the rigidity of the second land portion 14 in the tire axial direction is maintained, and excellent handling stability is exhibited.

[0049] FIG. 6 shows a cross - sectional view taken along line B - B of FIG. 2. As shown in FIG. 6, the transverse groove 30 preferably includes a rib 31 with a raised groove bottom. The rib 31 of the present embodiment is provided in a region including the end portion of the transverse groove 30 on the first circumferential direction groove 11 side. Such a rib 31 can enhance the handling stability while maintaining the wet performance.

[0050] The depth d3 from the ground contact surface of the second land portion 14 to the outer surface of the rib 31 is preferably 25% to 60% of the depth d2 of the first circumferential groove 11. Also, the length L5 of the rib 31 in the tire axial direction is preferably 4.0 to 11.0 times the depth d3. Such a rib 31 helps to enhance the wet performance and handling stability in a well-balanced manner. When the length of the rib 31 in the tire axial direction varies in the tire radial direction, the length L5 shall be measured at the center position of the rib 31 in the tire radial direction.

[0051] FIG. 7 shows a cross-sectional view taken along line C-C of FIG. 2. As shown in FIG. 7, in the lateral groove 30, at least one of the groove edges is formed by a chamfered portion 33. In this embodiment, both groove edges of the lateral groove 30 are formed by the chamfered portions 33. The chamfered portion 33 includes an inclined surface 34 that continues between the ground contact surface of the second land portion 14 and the groove wall of the lateral groove 30. Such a lateral groove 30 including the chamfered portion 33 can relieve the local high ground pressure acting on its edge.

[0052] The width W3 of the chamfered portion 33 in the tread plan view is preferably, for example, 1.0 to 2.5 mm. The depth d4 of the chamfered portion 33 is preferably, for example, 1.0 to 2.0 mm. Such a lateral groove 30 having the chamfered portion 33 helps to enhance the handling stability and wet performance in a well-balanced manner.

[0053] As described above, the tire according to an 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 with various modifications.

Example

[0054] As an example, a pneumatic tire with a size of 235 / 35ZR19 having the basic structure shown in FIG. 1 and provided with the above-described concave portion in the first land portion was manufactured. As Comparative Examples 1 to 6, tires provided with concave portions having dimensions outside the scope of the present disclosure were prototyped. The tires of Comparative Examples 1 to 6 are substantially the same as the tires of the example except for the above matters. For these test tires, the handling stability and wet performance on a dry road surface were tested. The common specifications and test methods of each test tire are as follows. Mounting rim: 19×8.0J Tire internal pressure: 260 kPa Test vehicle: Displacement 2000 cc, front-wheel drive Test tire mounting position: All wheels

[0055] <Handling stability on dry road surface> The handling stability when the test vehicle travels on a dry road surface was evaluated by the driver's sensory evaluation. The result is a score with Comparative Example 1 as 100, and the larger the numerical value, the better the handling stability on the dry road surface.

[0056] <Wet performance> The wet performance when the test vehicle travels on a wet road surface was evaluated by the driver's sensory evaluation. The result is a score with Comparative Example 1 as 100, and the larger the numerical value, the better the wet performance. The test results are shown in Tables 1 to 3.

[0057]

Table 1

[0058]

Table 2

[0059]

Table 3

[0060] As shown in Tables 1 to 3, Examples 1 to 17 obtained high ratings of 105 to 108 points for handling stability on dry roads. In contrast, Comparative Examples 1, 3, and 5 had handling stability ratings of 100 to 101 points. This is presumably because in Comparative Examples 1, 3, and 5, the dimensions of the recesses were smaller than those defined in the present disclosure, so the inner surfaces of the recesses could not be sufficiently grounded, and the handling stability was not sufficiently improved.

[0061] Also, Comparative Examples 2, 4, and 6 also had handling stability ratings of 100 to 101 points. This is presumably because in Comparative Examples 2, 4, and 6, the dimensions of the recesses were larger than those defined in the present disclosure, so the rigidity of the first land portion was impaired and the handling stability was reduced. As shown in Tables 1 to 3, it was confirmed that the tires of the present disclosure improved the handling stability on dry roads while maintaining the wet performance by specifically specifying the recesses.

[0062] [Appendix] The present disclosure includes the following aspects.

[0063] [Disclosure 1] A tire having a tread portion, The tread portion includes a first circumferential groove continuously extending in the tire circumferential direction and a first land portion disposed adjacent to the first circumferential groove, The first land portion includes a ground contact surface, a side wall on the first circumferential groove side, and at least one recess opening across both the ground contact surface and the side wall, In a plan view of the tread and a front view of the side wall, the recess defines the opening by a V-shaped edge, respectively, The maximum length L1 of the recess in the tire circumferential direction is 6.0 to 9.0 mm, The maximum depth d1 of the recess is 15% to 40% of the maximum depth of the first circumferential groove, The maximum length L2 of the recess in the tire axial direction is 3.0 to 5.0 times the depth d1, Tire. [Disclosure 2] The tire according to the first disclosure, wherein the recessed portion has a space surrounded by the inner surface of the recessed portion, the virtual extension surface of the ground contact surface, and the virtual extension surface of the side wall, and the space is in a triangular pyramid shape. [Third disclosure] The tire according to the first or second disclosure, wherein an opening area of the recessed portion on the ground contact surface is larger than an opening area of the recessed portion on the side wall. [Fourth disclosure] The tread portion includes a second circumferential groove that continuously extends in the tire circumferential direction inside the first circumferential groove in the tire axial direction. The tire according to any one of the first to third disclosures, wherein the first land portion is divided between the first circumferential groove and the second circumferential groove. [Fifth disclosure] The tire according to any one of the first to fourth disclosures, wherein a ground contact surface of the first land portion is continuous in the tire circumferential direction over the entire circumference of the tire. [Sixth disclosure] The tread portion includes a second land portion adjacent to the first land portion via the first circumferential groove. A lateral groove extending in the tire axial direction from the first circumferential groove is provided in the second land portion. The tire according to any one of the first to fifth disclosures, wherein an end portion of the lateral groove on the first circumferential groove side faces the recessed portion in a tread plan view. [Seventh disclosure] The tire according to the sixth disclosure, wherein a groove width at the end portion of the lateral groove is larger than a length L1 of the recessed portion. [Eighth disclosure] The tire according to the sixth or seventh disclosure, wherein the lateral groove includes a tiber with a raised groove bottom. [Ninth disclosure] The tire according to any one of the sixth to eighth disclosures, wherein at least one groove edge of the lateral groove is formed by a chamfered portion. [Tenth disclosure] The tire according to the ninth disclosure, wherein a maximum depth of the chamfered portion is smaller than a depth d1 of the recessed portion.

Description of reference numerals

[0064] 2 Tread portion 11 First-week direction groove 13 First land portion 17 Ground contact surface 18 Side wall 20 Concave portion L1 Maximum length of the concave portion in the tire circumferential direction L2 Maximum length of the concave portion in the tire axial direction d1 Maximum depth of the concave portion

Claims

1. A tire having a tread portion, wherein the tread portion includes a first circumferential groove continuously extending in the tire circumferential direction and a first land portion disposed adjacent to the first circumferential groove, the first land portion includes a ground contact surface, a side wall on the first circumferential groove side, and at least one recess opening across both the ground contact surface and the side wall, the recess defines the opening by a V-shaped edge in a tread plan view and a front view of the side wall, respectively, a maximum length L1 of the recess in the tire circumferential direction is 6.0 to 9.0 mm, a maximum depth d1 of the recess is 15% to 40% of a maximum depth of the first circumferential groove, a maximum length L2 of the recess in the tire axial direction is 3.0 to 5.0 times the depth d1, a tire.

2. The tire according to claim 1, wherein a space surrounded by an inner surface of the recess, a virtual extension surface of the ground contact surface, and a virtual extension surface of the side wall of the recess is triangular pyramid-shaped.

3. The tire according to claim 1 or 2, wherein an opening area of the recess on the ground contact surface is larger than an opening area of the recess on the side wall.

4. The tread portion includes a second circumferential groove continuously extending in the tire circumferential direction inside the first circumferential groove in the tire axial direction, the tire according to any one of claims 1 to 3, wherein the first land portion is divided between the first circumferential groove and the second circumferential groove.

5. The tire according to any one of claims 1 to 4, wherein the ground contact surface of the first land portion is continuous in the tire circumferential direction over the entire tire circumference.

6. The tread portion includes a second land portion adjacent to the first land portion via the first circumferential groove, a transverse groove extending in the tire axial direction from the first circumferential groove is provided in the second land portion, in a tread plan view, an end portion of the transverse groove on the first circumferential groove side faces the recess, the tire according to any one of claims 1 to 5.

7. The tire according to claim 6, wherein a groove width at the end portion of the transverse groove is larger than the length L1 of the recess.

8. The tire according to claim 6 or 7, wherein the transverse groove includes a tiber with a raised groove bottom.

9. The tire according to any one of claims 6 to 8, wherein at least one groove edge of the transverse groove is constituted by a chamfered portion.

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