tire

Abstract

To further improve wet performance, while maintaining dry-grip performance at the time of travelling under high load.SOLUTION: A tire 1 includes a first land part 3 including a first tread end T1 and a second land part 4 arranged adjacently, in a tire axial direction, to the first land part 3. A width Wa of the first land part 3 is larger than a width Wb of the second land part 4. The first land part 3 is provided with a first inner lateral groove 11 having a first inner terminating end 12 extending from a first circumferential groove 7, outwardly in the tire axial direction and terminating in the first land part 3, and a first outer lateral groove 13 having a first outer terminating end 14 extending from the first tread end T1, inwardly in the tire axial direction and terminating in the first land part 3.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Patent Document 1 below describes a tire that is expected to have excellent dry grip performance during high-load driving on a circuit or the like, and excellent wet performance. The tread portion of this tire includes first to third main grooves, an inner crown land portion, an outer crown land portion, an inner shoulder land portion, and an outer shoulder land portion, which are divided into the first to third main grooves. In addition, the outer crown land portion, the inner shoulder land portion, and the outer shoulder land portion have closed grooves that are closed within the land portions. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-167717 Summary of the Invention [Problem to be solved by the invention]

[0004] The above-described tire has a problem in that the drainage performance in the vicinity of the inner shoulder land portion is insufficient when running on wet conditions.

[0005] The present disclosure has been devised in view of the above-described circumstances, and has as its main object to provide a tire that can further improve wet performance while maintaining dry grip performance during high-load driving. [Means for solving the problem]

[0006] The present disclosure relates to a tire having a tread portion whose orientation when mounted on a vehicle is specified, wherein the tread portion includes a first tread edge located on the inner side of the vehicle when mounted on the vehicle, a first land portion including the first tread edge, a second land portion adjacent to the first land portion in the tire axial direction, and a first circumferential groove separating the first land portion from the second land portion, wherein the axial width of the first land portion is greater than the axial width of the second land portion, and the first land portion is provided with a first inner lateral groove extending from the first circumferential groove outward in the tire axial direction and having a first inner interrupted end that terminates within the first land portion, and a first outer lateral groove extending from the first tread edge inward in the tire axial direction and having a first outer interrupted end that terminates within the first land portion. [Effects of the Invention]

[0007] By employing the above configuration, the tire of the present disclosure can further improve wet performance while maintaining dry grip performance during high-load driving. [Brief explanation of the drawings]

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

[0009] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. FIG. 1 is a plan view showing a tread portion 2 of a tire 1 according to an embodiment of the present disclosure. The tire 1 of the present disclosure is used, for example, for a pneumatic tire for a passenger car that can perform high-load running on a circuit in addition to normal running on a public road. However, the tire 1 of the present disclosure is also used, for example, for a pneumatic tire for heavy loads or motorcycles, or a non-pneumatic tire not filled with compressed air inside.

[0010] The tread portion 2 has a defined mounting direction on the vehicle. Accordingly, the tread portion 2 has a first tread end T1 located on the vehicle inner side and a second tread end T2 located on the vehicle outer side when the tire 1 is mounted on the vehicle.

[0011] The first tread end T1 and the second tread end T2 are the outermost grounding positions in the tire axial direction when a normal load is applied to the tire 1 in a normal state and the tire is grounded on a plane with a camber angle of 0°. The "normal state" means that the tire 1 is rim-mounted on a normal rim (not shown) and filled with a normal internal pressure, and is in a non-loaded 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. Also, the separation distance in the tire axial direction between the first tread end T1 and the second tread end T2 is the tread width TW.

[0012] The "normal rim" is a rim defined for each tire in a standard system including the standard on which the tire 1 is based. For example, in JATMA, it is the "standard rim", in TRA, it is the "Design Rim", and in ETRTO, it is the "Measuring Rim".

[0013] The "normal internal pressure" is the air pressure defined for each tire in a standard system including the standard on which the tire 1 is based. In JATMA, it is the "maximum air pressure", in TRA, it is the maximum value described in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES", and in ETRTO, it is the "INFLATION PRESSURE".

[0014] The "normal load" is the load defined for each tire in a standard system including the standards on which the tire 1 is based. In the case of JATMA, it is the "maximum load capacity"; 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 "LOAD CAPACITY".

[0015] The tread portion 2 of the present embodiment includes a first land portion 3 including a first tread edge T1, a second land portion 4 adjacent to the first land portion 3 in the tire axial direction, and a first circumferential groove 7 that divides the first land portion 3 and the second land portion 4.

[0016] The width Wa in the tire axial direction of the first land portion 3 is formed to be larger than the width Wb in the tire axial direction of the second land portion 4. Thereby, since the first land portion 3 on which a relatively large lateral force acts has a high rigidity in the tire axial direction, the dry grip performance is maintained at a high level. Although not particularly limited, it is desirable that the width Wa of the first land portion 3 is 1.4 times or more, more desirably 1.5 times or more, desirably 1.9 times or less, and more desirably 1.8 times or less of the width Wb of the second land portion 4. The width Wa of the first land portion 3 is desirably 10% or more, more desirably 15% or more, desirably 30% or less, and more desirably 25% or less of the tread width TW, for example.

[0017] The first land portion 3 is provided with a first inner lateral groove 11 and a first outer lateral groove 13. The first inner lateral groove 11 extends outward in the tire axial direction from the first circumferential groove 7 and has a first inner break end 12 that terminates within the first land portion 3. The first outer lateral groove 13 extends inward in the tire axial direction from the first tread end T1 and has a first outer break end 14 that terminates within the first land portion 3. As described above, a relatively large lateral force acts on the first land portion 3 compared to the second land portion 4. In particular, in the tire 1 in which negative camber is adopted to improve the turning performance of a vehicle performing high-load running, a large contact pressure acts on the first land portion 3. In such a tire 1, in order to improve the wet performance, it is required to enhance the drainage performance of the first land portion 3. Therefore, as disclosed in the present application, the tire 1 provided with the first inner lateral groove 11 and the first outer lateral groove 13 in the first land portion 3 can smoothly discharge the water near the first land portion 3 to the first tread end T1 and the first circumferential groove 7, so that the wet performance is greatly improved. In this specification, each break end is located on the groove width center line of the lateral groove in which it is provided.

[0018] FIG. 2 is an enlarged view of the first land portion 3 in FIG. 1. As shown in FIG. 2, the first inner lateral groove 11 and the first outer lateral groove 13 of the present embodiment include portions that are inclined in the same direction with respect to the tire axial direction. Such first inner lateral groove 11 and first outer lateral groove 13 reduce the portion where a rigidity step of the first land portion 3 occurs and maintain a high dry grip performance.

[0019] The first inner circumferential groove 11 and the first outer circumferential groove 13 include portions 11a and 13a where the angles θ1 and θ2 with respect to the tire axis direction are equal to each other or the difference (θ1 - θ2) therebetween is 5 degrees or less. In this specification, the difference (θ1 - θ2) of the angles is an absolute value. The portion 11a preferably has a tire axis direction length L1a that is 70% or more, more preferably 80% of the tire axis direction length L1 of the first inner circumferential groove 11. The portion 13a preferably has a tire axis direction length L2a that is 70% or more, more preferably 80% of the tire axis direction length L2 of the first outer circumferential groove 13. The angle θ1 of the first inner circumferential groove 11 is the angle of the groove width center line 11c of the first inner circumferential groove 11. And the angle θ2 of the first outer circumferential groove 13 is the angle of the groove width center line 13c of the first outer circumferential groove 13.

[0020] The angle θ1i with respect to the tire axis direction at the first inner end 12 of the first inner circumferential groove 11 is, for example, equal to the angle θ2o with respect to the tire axis direction at the first outer end 14 of the first outer circumferential groove 13 or the difference (absolute value of θ1i - θ2o) therebetween is 5 degrees or less. Thereby, the above-described action is effectively exerted. The angle θ1i and the angle θ2o are the angles of the groove width center line 11c on the first inner end 12 and the angle of the groove width center line 13c on the first outer end 14, respectively.

[0021] The angle θ1i and the angle θ2o are desirably 5 degrees or more, more desirably 15 degrees or more, desirably 60 degrees or less, and more desirably 45 degrees or less. Since the angle θ1i and the angle θ2o are 5 degrees or more, the water in each of the circumferential grooves 11 and 13 can be smoothly discharged by utilizing the rotation of the tire 1. Since the angle θ1i and the angle θ2o are 60 degrees or less, a decrease in the lateral rigidity of the first land portion 3 can be suppressed.

[0022] The angle θ2e with respect to the tire axis direction at the first tread end T1 of the first outer circumferential groove 13 is desirably 0 degrees ± 5 degrees. Thereby, a decrease in the rigidity on the first tread end T1 of the first land portion 3 is suppressed to a small extent. The angle θ2e is the angle of the groove width center line 13c on the first tread end T1.

[0023] Figure 3 is an enlarged view of the first land portion 3 and the second land portion 4 in Figure 1. As shown in Figure 3, in this embodiment, the first inner lateral groove 11 includes a first portion 15 having a first inner interrupted end 12. In this embodiment, the first portion 15 is a portion where the groove width center line 11c extends linearly in the tread plan view. The term "linearly" in this specification includes, in the tread plan view, not only those in which the groove width center line extends linearly, but also those in which the groove width center line extends in an arc with a radius of curvature R1 of 200 mm or more.

[0024] The first outer lateral groove 13 includes a second portion 16 including a first outer interrupted end 14 and a third portion 17 connecting the second portion 16 and the first tread end T1. In this embodiment, the second portion 16 is a portion where the groove width center line 13c extends linearly in the tread plan view. In this embodiment, the third portion 17 is a portion where the groove width center line 13c extends in an arc shape in the tread plan view. The arc shape in this specification means that in the tread plan view, the radius of curvature R1 of the groove width center line extends with a radius of curvature R1 of less than 200 mm.

[0025] In this embodiment, the first inner interrupted end 12 is located closer to the first tread end T1 than the first outer interrupted end 14. As a result, in the first land portion 3, an overlapping portion Y where the first inner lateral groove 11 and the first outer lateral groove 13 overlap in the tire axial direction is formed. Such an overlapping portion Y can increase the discharge amount of water near the first land portion 3, thereby improving the wet performance. In order to enhance the dry grip performance and the wet performance in a well-balanced manner, the length La of the overlapping portion Y in the tire axial direction is desirably 3% or more, more desirably 5% or more, desirably 15% or less, and more desirably 10% or less of the width Wa of the first land portion 3.

[0026] On the first land portion 3, a first sipe 19 is provided that connects the first inner end 12 of the first inner lateral groove 11 and the first tread end T1. Such a first sipe 19 sucks water on the first land portion 3 and discharges it to the first inner lateral groove 11 and the first tread end T1, thereby enhancing wet performance. A sipe, as used in this specification, is formed in a cut shape with a width of less than 1.5 mm. Therefore, a sipe is clearly distinguishable from a circumferential groove or a lateral groove with a groove width of 1.5 mm or more.

[0027] In this embodiment, the first sipe 19 extends linearly in the longitudinal direction. The first sipe 19 may extend, for example, in a zigzag shape or a wavy shape. The first sipe 19 is inclined, for example, with respect to the tire axis direction.

[0028] The angle θ1i (shown in FIG. 2) with respect to the tire axis direction at the first inner end 12 of the first inner lateral groove 11 is preferably equal to the angle θ3 of the first sipe 19 with respect to the tire axis direction, or the difference (θ1i - θ3) is 5 degrees or less. Thereby, the water in the first sipe 19 can flow smoothly into the first inner lateral groove 11, further improving wet performance. The difference in angles (θ1i - θ3) is an absolute value in this specification.

[0029] In a tread plan view, the first inner lateral groove 11 is formed so as to completely enclose a virtual extension line 19x obtained by extending the first sipe 19 along its longitudinal direction on the first land portion 3. Thereby, the first inner lateral groove 11 and the first sipe 19 contact the ground at the same timing, and these lateral grooves 11 and the first sipe 19 are deformed so as to open widely, increasing the apparent groove volume and the sipe volume. For this reason, wet performance is improved. In this specification, the "virtual extension line" is a line obtained by extending the groove width center line or the center line of the sipe. The "completely enclose" means, in this specification, that the virtual extension line is continuously located above the lateral groove from the inner end to the outer end in the tire axis direction of the lateral groove.

[0030] The groove width W5 of the first outer transverse groove 13 is formed, for example, to be larger than the groove width W4 of the first inner transverse groove 11. Also, the length L2 (shown in FIG. 2) of the first outer transverse groove 13 is formed to be larger than the length L1 of the first inner transverse groove 11 in the present embodiment. Thereby, since the first outer transverse groove 13 can collect more water near the first land portion 3 than the first inner transverse groove 11 and discharge it to the outside of the first tread edge T1, the wet performance is enhanced. The groove width W5 of the first outer transverse groove 13 is desirably 1.1 times or more, more desirably 1.2 times or more, desirably 1.4 times or less, and more desirably 1.3 times or less of the groove width W4 of the first inner transverse groove 11. The groove width W5 of the first outer transverse groove 13 is desirably 10% or more, more desirably 15% or more, desirably 30% or less, and more desirably 25% or less of the width Wa of the first land portion 3. The length L2 of the first outer transverse groove 13 is desirably 55% or more, more desirably 60% or more, desirably 75% or less, and more desirably 70% or less of the width Wa of the first land portion 3.

[0031] In a plan view of the tread, the first land portion 3 includes an acute corner land portion K1 formed between the first inner transverse groove 11 and the first circumferential groove 7.

[0032] FIG. 4 is a perspective view of the acute corner land portion K1. As shown in FIG. 4, the tread wall surface 3b of the acute corner land portion K1 includes a chamfered portion 20 that gently slopes from the tread surface 3a side toward the groove width center line 11c side of the first inner transverse groove 11 in the present embodiment. The tread wall surface 3b further includes, for example, a first wall surface portion 21 and a second wall surface portion 22. The first wall surface portion 21 of the present embodiment extends inward in the tire radial direction from the tread surface 3a. The second wall surface portion 22 of the present embodiment extends outward in the tire radial direction from the groove bottom 11s of the first inner transverse groove 11. The first wall surface portion 21 and the second wall surface portion 22 are inclined at an angle smaller than that with respect to the normal line n of the tread surface 3a, for example, than the chamfered portion 20. The chamfered portion 20 connects, for example, the first wall surface portion 21 and the second wall surface portion 22. Such an acute corner land portion K1 suppresses a decrease in the rigidity of the first land portion 3.

[0033] The land portion K1 of the acute-angle corner includes the land edge 24 which is the boundary between the tread wall surface 3b and the tread surface 3a. The land edge 24 of the present embodiment is formed in a single arc shape with a radius of curvature R2 in the tread plan view. The acute-angle corner land portion K1 where such a land edge 24 is formed further suppresses the decrease in the rigidity of the first land portion 3. The radius of curvature R2 of the land edge 24 is desirably, for example, 5 mm or more, more desirably 6 mm or more, desirably 9 mm or less, and more desirably 8 mm or less.

[0034] The first land portion 3 includes, for example, an obtuse-angle corner land portion K2 formed between the first inner lateral groove 11 and the first circumferential groove 7. The obtuse-angle corner land portion K2 of the present embodiment is not provided with the chamfered portion as described above.

[0035] As shown in FIG. 1, in the present embodiment, the tread portion 2 further includes a second land portion 4, a third land portion 5 adjacent to the second land portion 4 in the tire axial direction, and a fourth land portion 6 including the second tread end T2 adjacent to the third land portion 5 in the tire axial direction. Further, the tread portion 2 includes, for example, a second circumferential groove 8 that divides the second land portion 4 and the third land portion 5, and a third circumferential groove 9 that divides the third land portion 5 and the fourth land portion 6.

[0036] The second circumferential groove 8 of the present embodiment is adjacent to the first circumferential groove 7. In the present embodiment, the second circumferential groove 8 is located on the first tread end T1 side with respect to the tire equator C. For example, the center line 8c of the groove width of the second circumferential groove 8 is located on the first tread end T1 side with respect to the tire equator C.

[0037] The third circumferential groove 9 of the present embodiment is located on the second tread end T2 side with respect to the second circumferential groove 8. For example, the third circumferential groove 9 is located on the second tread end T2 side with respect to the tire equator C. The first circumferential groove 7, the second circumferential groove 8, and the third circumferential groove 9 extend linearly continuously in the tire circumferential direction, for example. Note that each of the circumferential grooves 7 to 9 may extend in a zigzag shape or in a wavy shape.

[0038] The groove width W2 of the second circumferential groove 8 is formed larger than the groove width W1 of the first circumferential groove 7. The groove width W3 of the third circumferential groove 9 is formed smaller than the groove width W1 of the first circumferential groove 7. The groove width W1 of the first circumferential groove 7 is desirably 3% or more of the tread width TW, more desirably 5% or more, desirably 8% or less, and more desirably 6% or less. The groove depth d1 (shown in FIG. 4) of the first circumferential groove 7 is, for example, 5.0 to 7.5 mm.

[0039] The width Wc in the tire axial direction of the third land portion 5 is formed smaller than the width Wa of the first land portion 3 and larger than the width Wb of the second land portion 4. The width Wd in the tire axial direction of the fourth land portion 6 is formed larger than the width Wa in the tire axial direction of the first land portion 3. The width Wc of the third land portion 5 is desirably 0.7 times or more of the width Wa of the first land portion 3, more desirably 0.75 times or more, desirably 0.9 times or less, and more desirably 0.85 times or less. The width Wd of the fourth land portion 6 is desirably 1.15 times or more of the width Wa of the first land portion 3, more desirably 1.2 times or more, desirably 1.35 times or less, and more desirably 1.3 times or less.

[0040] As shown in FIG. 3, the second land portion 4 of the present embodiment is provided with a second sipe 25 and a recess 26 formed by notching a land edge 4e extending in the tire circumferential direction of the second land portion 4.

[0041] The recess 26 includes a first recess 26a connected to the first circumferential groove 7 and a second recess 26b connected to the second circumferential groove 8. Such a recess 26 helps to increase the apparent groove volume of each circumferential groove 7, 8.

[0042] The recess 26 is, for example, such that the length Lb in the tire circumferential direction decreases toward the intermediate position 4c in the tire axial direction of the second land portion 4. In the present embodiment, the length Lb in the tire circumferential direction of the recess 26 continuously decreases toward the intermediate position 4c of the second land portion 4. In a plan view of the tread, the recess 26 is, for example, triangular in shape. Such a recess 26 suppresses a decrease in the land rigidity of the second land portion 4. The recess 26 is not limited to such a shape.

[0043] The maximum value of the length Lb of the recess 26 is desirably 120% or more, more desirably 130% or more, desirably 160% or less, and more desirably 150% or less of the length Lc of the recess 26 in the tire axial direction. The length Lc of the recess 26 in the tire axial direction is desirably 10% or more, more desirably 15% or more, desirably 30% or less, and more desirably 25% or less of the width Wb (shown in FIG. 1) of the second land portion 4. The depth of the recess 26 (not shown) is desirably 55% or more, more desirably 65% or more, and more desirably 100% or less of the groove depth d1 of the first circumferential groove 7.

[0044] The second sipe 25 of the present embodiment crosses the second land portion 4. Such a second sipe 25 enhances wet performance. In the present embodiment, the second sipe 25 extends so as to connect the first recess 26a and the second recess 26b. As a result, the second sipe 25 and the recess 26 come into contact with the ground at the same timing, so that both deform so as to open widely, increasing the apparent volume and improving wet performance.

[0045] In the second land portion 4, except for the second sipe 25, no transverse grooves and sipings that cross the second land portion 4 are provided. Thereby, a decrease in the land rigidity of the second land portion 4 where a large ground pressure acts during straight running is suppressed. For this reason, excellent dry grip performance is exhibited.

[0046] FIG. 5 is an enlarged view of the third land portion 5 and the fourth land portion 6 of FIG. 1. In the third land portion 5 of the present embodiment, a third transverse groove 28, a third groove 29, and a third sipe 30 are provided. The third transverse groove 28 and the third groove 29 are arranged alternately, for example, along the tire circumferential direction.

[0047] In the present embodiment, the third transverse groove 28 crosses the third land portion 5. In the present embodiment, the third groove 29 extends from the second circumferential groove 8 toward the second tread end T2 and has a third break end 31 that is interrupted within the third land portion 5.

[0048] The third transverse lateral grooves 28 and the third lateral grooves 29 are, for example, inclined in the same direction relative to the tire axial direction. This reduces the rigidity step occurring in the third land portion 5. In this embodiment, the third transverse lateral grooves 28 and the third lateral grooves 29 extend parallel to each other. The third transverse lateral grooves 28 and the third lateral grooves 29 extend linearly, for example. This improves wet performance. The angle θ4 of the third transverse lateral groove 28 relative to the tire axial direction and the angle θ5 of the third lateral groove 29 relative to the tire axial direction are, for example, preferably 10 degrees or more, more preferably 15 degrees or more, more preferably 30 degrees or less, and even more preferably 25 degrees or less. In this specification, the term "parallel" includes not only a case where the absolute value of the difference between the respective angles is 0 degrees, but also 5 degrees or less.

[0049] In the present embodiment, the third lateral grooves 29 are formed so as to completely encompass imaginary extension lines 30x that extend from the third sipes 30 onto the third land portions 5 along their longitudinal directions in a plan view of the tread.

[0050] 1, in a plan view of the tread, the third transverse lateral grooves 28 of the third land portion 5 are formed so as to completely encompass imaginary extension lines 25x that extend the second sipes 25 along their longitudinal directions onto the third land portion 5. This causes the third transverse lateral grooves 28 and the second sipes 25 to deform so as to open widely, increasing the apparent groove volume and sipe volume, thereby further improving wet performance.

[0051] As shown in Figure 5, the axial length L3 of the third lateral grooves 29 is preferably 40% or more of the width Wc (shown in Figure 1) of the third land portion 5, more preferably 45% or more, and more preferably 60% or less, and even more preferably 55% or less. Since the length L3 of the third lateral grooves 29 is 40% or more of the width Wc of the third land portion 5, wet performance is maintained. Since the length L3 of the third lateral grooves 29 is 60% or less of the width Wc of the third land portion 5, dry grip performance is maintained.

[0052] The groove width W7 of the third transverse groove 29 is, for example, the same as the groove width W6 of the third transverse circumferential groove 28. Thereby, the rigidity step of the third land portion 5 is maintained small. In the present embodiment, the maximum value of the groove width W7 of the third transverse groove 29 and the maximum value of the groove width W6 of the third transverse circumferential groove 28 are the same. In this specification, the term "the same" includes not only the case where the difference in the groove width of each transverse groove is 0 mm, but also the case where the absolute value of these differences is within 3 mm.

[0053] In the present embodiment, the third sipe 30 connects the third circumferential groove 9 and the third transverse groove 29. The third sipe 30 is connected to, for example, the third break end 31. The third sipe 30 of the present embodiment extends linearly.

[0054] The fourth land portion 6 of the present embodiment includes a fourth transverse groove 35 that extends from the third circumferential groove 9 toward the second tread end T2 side, and a fourth small transverse groove 36 whose both ends are interrupted within the fourth land portion 6.

[0055] In the present embodiment, the fourth transverse groove 35 includes a fourth portion 35A that extends linearly from the third circumferential groove 9, and a fifth portion 35B that is continuous with the fourth portion 35A and extends in an arc shape. The fifth portion 35B includes a fifth break end 37 that is interrupted within the fourth land portion 6.

[0056] The fourth small transverse groove 36 includes a sixth portion 36A that extends linearly, and a seventh portion 36B that is continuous with the sixth portion 36A and extends in an arc shape. Each of the sixth portion 36A and the seventh portion 36B includes a sixth break end 38 and a seventh break end 39 that are interrupted within the fourth land portion 6.

[0057] Although not particularly limited, the tire axial length L4 of the fourth transverse groove 35 is desirably 80% or more, more desirably 85% or more, desirably 98% or less, and more desirably 95% or less of the width Wd (shown in FIG. 1) of the fourth land portion 6. Also, the tire axial length L5 of the fourth small transverse groove 36 is desirably 65% or more, more desirably 70% or more, desirably 85% or less, and more desirably 80% or less of the width Wd of the fourth land portion 6.

[0058] In this embodiment, the fourth portion 35A and the sixth portion 36A extend parallel to each other. The angle θ6 of the fourth portion 35A with respect to the tire axial direction and the angle θ7 of the sixth portion 36A with respect to the tire axial direction are, for example, preferably 10 degrees or more, more preferably 15 degrees or more, and more preferably 30 degrees or less, and even more preferably 25 degrees or less.

[0059] Although not particularly limited, the axial length L4a of the fourth portion 35A is preferably 75% or more, more preferably 80% or more, and more preferably 95% or less, and more preferably 90% or less of the axial length L4 of the fourth lateral groove 35. The axial length L5a of the sixth portion 36A is preferably 70% or more, more preferably 75% or more, and more preferably 90% or less, of the length L5 of the fourth small lateral groove 36.

[0060] In a plan view of the tread, the fourth lateral groove 35 is formed so as to encompass an imaginary extension line 28x obtained by extending the third transverse lateral groove 28 onto the fourth land portion 6 along its longitudinal direction. The fourth portion 35A of the fourth lateral groove 35 is formed, for example, so as to completely encompass the imaginary extension line 28x. The fourth lateral groove 35 is also formed so as to encompass an imaginary extension line 25x (shown in FIG. 1 ) obtained by extending the second sipe 25 to the third land portion 5 and the fourth land portion 6. The fourth small lateral groove 36 is also formed so as to encompass an imaginary extension line 30y obtained by extending the third sipe 30 onto the fourth land portion 6 along its longitudinal direction. The sixth portion 36A of the fourth small lateral groove 36, for example, completely encompasses the imaginary extension line 30y.

[0061] As shown in Fig. 1, each of the lateral grooves arranged in the tread portion 2 of this embodiment is inclined in the same direction relative to the tire axial direction. For example, each of the lateral grooves is inclined in a first direction (rising upward to the right in Fig. 1) relative to the tire axial direction. This allows water in each lateral groove to be smoothly discharged toward one side in the tire axial direction by utilizing the rotation of the tire 1. Each of the sipes arranged in the tread portion 2 is also inclined in the same direction relative to the tire axial direction. For example, each of the sipes is inclined in the first direction.

[0062] The first inner lateral groove 11, the first outer lateral groove 13, and the first sipe 19 formed in the first land portion 3 are, for example, more inclined with respect to the tire axis direction than the second sipe 25, the third transverse groove 28, the third groove 29, the third sipe 30, the fourth groove 35, and the fourth small transverse groove 36 formed in the second land portion 4 to the fourth land portion 6. Such a tread portion 2 can enhance the drainage performance near the first land portion 3 while maintaining a high dry grip performance in the second land portion 4 to the fourth land portion 6.

[0063] As described above, although one embodiment of the present disclosure has been described in detail, the present disclosure is not limited to the above specific embodiment and can be implemented in various modes.

Example

[0064] A tire having the basic pattern of FIG. 1 was prototyped based on the specifications in Table 1. Then, the dry grip performance and wet performance of each test tire were tested. The common specifications of each test tire and the test method are as follows.

[0065] <Dry grip performance · Wet performance> Each test tire was mounted on all the wheels of the following test vehicle. A test driver drove the test vehicle at high speed on a test course on a dry asphalt road surface and a test course on an asphalt road surface provided with a water puddle with a water depth of 5 mm. The dry grip performance and wet performance based on the stability and operability at this time were evaluated by the sensory evaluation of the test driver. The results are all shown in scores with Comparative Example 1 as 100. The larger the numerical value, the better. If any numerical value is 90 or less, the tire is regarded as a failed tire. Tire size: 245 / 40R18 Rim: 18×8.5J Internal pressure: 220 kPa (all wheels) Vehicle: Four-wheel drive vehicle with a displacement of 2000 cc Tread width TW: 268 mm The test results are shown in Tables 1 and 2. "A" is a shape in which the first inner lateral groove extends from the first tread edge and terminates at the first land portion. "B" is a shape in which the first outer lateral groove extends from the first circumferential groove and terminates at the first land portion. "C" is a shape that crosses the first land area. "D" is a shape in which both ends end at the first land area. "E" is a shape in which the second circumferential groove is located closer to the second tread edge than the tire equator.

[0066] [Table 1]

[0067] [Table 2]

[0068] As a result of the test, it was confirmed that the tires of the examples had excellent wet performance. In addition, it was confirmed that the tires of the examples maintained high dry grip performance.

[0069] [Note] The present disclosure includes the following aspects.

[0070] [Disclosure 1] A tire having a tread portion whose mounting direction on a vehicle is specified, the tread portion includes a first tread edge located on an inner side of a vehicle when mounted on the vehicle, a first land portion including the first tread edge, a second land portion adjacent to the first land portion in the tire axial direction, and a first circumferential groove separating the first land portion and the second land portion, The width of the first land portion in the tire axial direction is larger than the width of the second land portion in the tire axial direction, The first land portion is provided with a first inner lateral groove extending from the first circumferential groove to the outside in the tire axial direction and having a first inner interrupted end that terminates within the first land portion, and a first outer lateral groove extending from the first tread edge to the inside in the tire axial direction and having a first outer interrupted end that terminates within the first land portion. tire. [Disclosure 2] The tire according to Disclosure 1, wherein the first inner lateral groove and the first outer lateral groove each include a portion inclined in the same direction relative to the tire axial direction. [Disclosure 3] The tire according to Disclosure 1 or 2, wherein the first inner lateral groove and the first outer lateral groove include portions where the angles relative to the tire axial direction are equal to each other or the difference therebetween is 5 degrees or less. [Disclosure 4] The tire according to any one of Disclosures 1 to 3, wherein an angle θ1i of the first inner lateral groove at the first inner end with respect to the tire axial direction is equal to an angle θ2o of the first outer lateral groove at the first outer end with respect to the tire axial direction, or the difference therebetween is 5 degrees or less. [Disclosure 5] The tire according to Disclosure 4, wherein the angle θ1i and the angle θ2o are 5 to 60 degrees. [Disclosure 6] The tire according to any one of Present Disclosures 1 to 5, wherein the first land portion is provided with a first sipe connecting the first inner discontinuous end of the first inner lateral groove and the first tread edge. [Disclosure 7] A tire described in the present disclosure 6, wherein the angle of the first inner lateral groove with respect to the tire axial direction at the first inner discontinuous end is equal to the angle of the first sipe with respect to the tire axial direction, or the difference therebetween is 5 degrees or less. [Disclosure 8] The tire according to any one of Disclosures 1 to 7, wherein the angle of the first outer lateral groove with respect to the tire axial direction at the first tread edge is 0 degrees ±5 degrees. [Disclosure 9] In a tread plan view, the first land portion includes an acute-angle corner land portion formed between the first inner lateral groove and the first circumferential groove, The tire according to any one of Disclosures 1 to 8, wherein the tread wall surface of the acute corner land portion includes a chamfered portion that gently slopes from the tread surface toward the groove width center line of the first inner lateral groove. [Disclosure 10] the tread wall surface of the acute corner land portion includes a first wall surface portion extending inward in the tire radial direction from the tread surface side and a second wall surface portion extending outward in the tire radial direction from a groove bottom of the first inner lateral groove, The tire according to the present disclosure 9, wherein the chamfered portion connects the first wall surface portion and the second wall surface portion. [Disclosure 11] the acute-angle corner land portion includes a land edge that is a boundary between the tread wall surface and the tread surface, The tire according to Disclosure 9 or 10, wherein, in a plan view of the tread, the land portion edge has a single arc-shaped curvature radius. [Disclosure 12] the tread portion includes a second tread edge located on an outer side of the vehicle when the tire is mounted on the vehicle, a second circumferential groove adjacent to the first circumferential groove, and a third circumferential groove located closer to the second tread edge than the second circumferential groove, the first circumferential groove and the second circumferential groove are located closer to a first tread edge than a tire equator, The tire according to any one of Present Disclosures 1 to 11, wherein the third circumferential groove is located closer to the second tread edge than the tire equator. [Disclosure 13] The tire according to present disclosure 12, wherein each of the first circumferential groove, the second circumferential groove, and the third circumferential groove extends continuously and linearly in the tire circumferential direction. [Explanation of symbols]

[0071] 1 tire 3 1st Land Department 4 2nd Land Department 7 First circumferential groove 11 First medial lateral groove 12 First inner break 13 1st outer transverse groove 14 First outer edge Wa Width of the first land area Wb Width of the second land area T1 First tread edge

Claims

1. A tire having a tread portion with a defined mounting orientation on a vehicle, wherein the tread portion includes a first tread edge located on the inner side of the vehicle when the tire is mounted on the vehicle, a first land portion including the first tread edge, a second land portion adjacent to the first land portion in the tire axial direction, and a first circumferential groove that divides the first land portion and the second land portion, wherein the width of the first land portion in the tire axial direction is larger than the width of the second land portion in the tire axial direction, wherein the first land portion is provided with a first inner lateral groove having a first inner break end that extends outward in the tire axial direction from the first circumferential groove and terminates within the first land portion, and a first outer lateral groove having a first outer break end that extends inward in the tire axial direction from the first tread edge and terminates within the first land portion, in a tread plan view, the first land portion includes an acute corner land portion formed between the first inner lateral groove and the first circumferential groove, wherein the tread wall surface of the acute corner land portion includes a chamfered portion that gently slopes from the tread surface side toward the groove width center line side of the first inner lateral groove, wherein the tread wall surface of the acute corner land portion includes a first wall surface portion that extends inward in the tire radial direction from the tread surface side, and a second wall surface portion that extends outward in the tire radial direction from the groove bottom of the first inner lateral groove, wherein the chamfered portion connects the first wall surface portion and the second wall surface portion, a tire.

2. A tire having a tread portion with a defined mounting orientation on a vehicle, wherein the tread portion includes a first tread edge located on the inner side of the vehicle when the tire is mounted on the vehicle, a first land portion including the first tread edge, a second land portion adjacent to the first land portion in the tire axial direction, and a first circumferential groove that divides the first land portion and the second land portion, wherein the width of the first land portion in the tire axial direction is larger than the width of the second land portion in the tire axial direction, wherein the first land portion is provided with a first inner lateral groove having a first inner break end that extends outward in the tire axial direction from the first circumferential groove and terminates within the first land portion, and a first outer lateral groove having a first outer break end that extends inward in the tire axial direction from the first tread edge and terminates within the first land portion, in a tread plan view, the first land portion includes an acute corner land portion formed between the first inner lateral groove and the first circumferential groove, wherein the tread wall surface of the acute corner land portion includes a chamfered portion that gently slopes from the tread surface side toward the groove width center line side of the first inner lateral groove, The land portion of the acute-angled corner includes a land edge that is a boundary between the tread wall surface and the tread surface, In a tread plan view, the land edge has a single arc shape with a radius of curvature, Tire.

3. The tire according to claim 1 or 2, wherein the first inner lateral groove and the first outer lateral groove include portions that are inclined in the same direction with respect to the tire axial direction.

4. The tire according to any one of claims 1 to 3, wherein the first inner lateral groove and the first outer lateral groove include portions where the angles with respect to the tire axial direction are equal or the difference therebetween is 5 degrees or less.

5. The tire according to any one of claims 1 to 4, wherein an angle θ1i with respect to the tire axial direction at the first inner end of interruption of the first inner lateral groove is equal to or the difference from an angle θ2o with respect to the tire axial direction at the first outer end of interruption of the first outer lateral groove is 5 degrees or less.

6. The tire according to claim 5, wherein the angles θ1i and θ2o are 5 to 60 degrees.

7. The tire according to any one of claims 1 to 6, wherein a first sipe connecting the first inner end of interruption of the first inner lateral groove and the first tread end is provided in the first land portion.

8. The tire according to claim 7, wherein an angle with respect to the tire axial direction at the first inner end of interruption of the first inner lateral groove is equal to or the difference from an angle with respect to the tire axial direction of the first sipe is 5 degrees or less.

9. The tire according to any one of claims 1 to 8, wherein an angle with respect to the tire axial direction at the first tread end of the first outer lateral groove is 0 degrees ± 5 degrees.

10. The tread wall surface of the land portion of the acute-angled corner includes a first wall surface portion extending inward in the tire radial direction from the tread surface side and a second wall surface portion extending outward in the tire radial direction from the groove bottom of the first inner lateral groove, The chamfered portion connects the first wall surface portion and the second wall surface portion. The tire according to claim 2.

11. The land portion of the acute-angled corner includes a land edge that is a boundary between the tread wall surface and the tread surface, In a tread plan view, the land edge has a single arc shape with a radius of curvature. The tire according to claim 1.

12. The tread portion includes a second tread end located on the outer side of the vehicle when mounted on the vehicle, a second circumferential groove adjacent to the first circumferential groove, and a third circumferential groove located on the second tread end side of the second circumferential groove. The first circumferential groove and the second circumferential groove are located on the first tread end side with respect to the tire equator. The third circumferential groove is located on the second tread end side with respect to the tire equator. The tire according to any one of claims 1 to 11.

13. Each of the first circumferential groove, the second circumferential groove, and the third circumferential groove extends linearly and continuously in the tire circumferential direction. The tire according to claim 12.

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