tire

Abstract

To provide a tire capable of reducing pattern noise, while maintaining snow traction.SOLUTION: In a tire 1, a tread part 2 includes, between an outer tread end 3 and an inner tread end 4, a plurality of circumferential grooves 5 extending continuously in a tire circumferential direction and a plurality of lateral grooves 6 extending in a direction in which the grooves cross the circumferential grooves 5. The circumferential groove 5 is constituted of an outer shoulder circumferential groove 5A, an outer crown circumferential groove 5B, an inner crown circumferential groove 5C and an inner shoulder circumferential groove 5D arranged in this order, from the outer tread end 3 side toward the inner tread end 4 side. A groove width W1 of the outer shoulder circumferential groove 5A, a groove width W2 of the outer crown circumferential groove 5B, a groove width W3 of the inner crown circumferential groove 5C and a groove width W4 of the inner shoulder circumferential groove 5D satisfy the following relation: W1<W2<W3<W4.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Patent Document 1 below describes a pneumatic tire. This tire has a tread portion provided with a center main groove that extends continuously in the tire circumferential direction on the tire equator side, and shoulder main grooves that extend continuously in the tire circumferential direction on the ground contact edge side of the center main groove. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-224245 A Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, consideration for the living environment has become important, and there is a demand for reducing tire pattern noise. There is also a demand for sufficient traction on snowy roads.

[0005] The present invention has been devised in view of the above circumstances, and has as its main object to provide a tire that is capable of reducing pattern noise while maintaining snow traction. [Means for solving the problem]

[0006] The present invention is a tire including a tread portion having a specified orientation for installation on a vehicle, the tread portion including an outer tread edge located on the outer side of the vehicle when installed on the vehicle, an inner tread edge located on the inner side of the vehicle when installed on the vehicle, a plurality of circumferential grooves extending continuously in the tire circumferential direction between the outer tread edge and the inner tread edge, and a plurality of lateral grooves extending in a direction intersecting the circumferential grooves, the circumferential grooves including an outer shoulder circumferential groove, an outer crown circumferential groove, an inner crown circumferential groove, and an inner shoulder circumferential groove arranged in this order from the outer tread edge side to the inner tread edge side, and a groove width W1 of the outer shoulder circumferential groove, a groove width W2 of the outer crown circumferential groove, a groove width W3 of the inner crown circumferential groove, and a groove width W4 of the inner shoulder circumferential groove satisfy the following relationship. W1 <W2<W3<W4

[0007] In the tire according to the present invention, the tread portion may include an inner middle land portion partitioned between the inner shoulder circumferential groove and the inner crown circumferential groove, and the lateral grooves may include a plurality of inner middle lateral grooves extending from the inner shoulder circumferential groove to the inner crown circumferential groove.

[0008] In the tire according to the present invention, the tread portion includes a crown land portion partitioned between the outer crown circumferential groove and the inner crown circumferential groove, and the lateral groove includes a plurality of crown lateral grooves, each of which may extend from the inner crown circumferential groove and terminate within the crown land portion.

[0009] In the tire according to the present invention, the crown lateral groove may include a first opening opening into the inner crown circumferential groove, and the inner middle lateral groove may include a second opening opening into the inner crown circumferential groove, and the first opening may be provided at a position different from the second opening in the tire circumferential direction so as not to face the second opening.

[0010] In the tire according to the present invention, a sum of a total maximum groove width of all the crown lateral grooves and a total maximum groove width of all the inner middle lateral grooves may be 30% to 40% of a circumference of the tread portion.

[0011] In the tire according to the present invention, the tread portion may include an inner shoulder land portion partitioned between the inner shoulder circumferential groove and the inner tread edge, and the lateral groove may include a plurality of inner shoulder lateral grooves extending from the inner shoulder circumferential groove to the inner tread edge.

[0012] In the tire according to the present invention, the inner middle lateral groove may include a third opening opening into the inner shoulder circumferential groove, and the inner shoulder lateral groove may include a fourth opening opening into the inner shoulder circumferential groove, and the third opening may be provided at a position different from the fourth opening in the tire circumferential direction so as not to face the fourth opening.

[0013] In the tire according to the present invention, a sum of a total maximum groove width of all the inner shoulder lateral grooves and a total maximum groove width of all the inner middle lateral grooves may be 20% to 30% of a circumference of the tread portion.

[0014] In the tire according to the present invention, the tread portion may include an outer middle land portion partitioned between the outer shoulder circumferential groove and the outer crown circumferential groove, and the lateral groove may include a plurality of first outer middle lateral grooves extending from the outer shoulder circumferential groove and terminated within the outer middle land portion.

[0015] In the tire according to the present invention, the lateral groove may include a plurality of second outer middle lateral grooves extending from the outer crown circumferential groove and terminated within the outer middle land portion.

[0016] In the tire according to the present invention, the first outer middle lateral groove may include a fifth opening opening into the outer shoulder circumferential groove, and the second outer middle lateral groove may include a sixth opening opening into the outer crown circumferential groove, the fifth opening being provided at a position different from the sixth opening in the tire circumferential direction.

[0017] In the tire according to the present invention, the tread portion includes an outer middle land portion partitioned between the outer shoulder circumferential groove and the outer crown circumferential groove, and an inner middle land portion partitioned between the inner shoulder circumferential groove and the inner crown circumferential groove, and a land ratio of the outer middle land portion may be 80% to 120% of a land ratio of the inner middle land portion.

[0018] In the tire according to the present invention, the tread portion includes an outer shoulder land portion partitioned between the outer shoulder circumferential groove and the outer tread edge, and an inner shoulder land portion partitioned between the inner shoulder circumferential groove and the inner tread edge, and a land ratio of the outer shoulder land portion may be 100% to 150% of a land ratio of the inner shoulder land portion. Effect of the Invention

[0019] By employing the above-mentioned configuration, the tire of the present invention can reduce pattern noise while maintaining snow traction. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a development view showing an example of a tread portion of a tire. [Diagram 2] 2 is a cross-sectional view taken along line AA in FIG. 1. [Diagram 3] FIG. 2 is a partial enlarged view of a crown land portion and an inner middle land portion. [Figure 4] FIG. 4 is a partial enlarged view of an inner middle land portion and an inner shoulder land portion. [Diagram 5] FIG. 4 is a partial enlarged view of an outer middle land portion and an outer shoulder land portion. [Figure 6] 1A is a development view of the tread portion of Comparative Example 1, and FIG. 1B is a development view of the tread portion of Comparative Example 2. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1 shows a development view of an example of a tread portion 2 of a tire 1. The tire 1 of this embodiment is suitably used, for example, as a pneumatic tire for a passenger vehicle. However, the present invention is not limited to such an embodiment, and may be used, for example, as a pneumatic tire for heavy loads or a non-pneumatic tire in which pressurized air is not filled inside the tire.

[0022] [Tread section] The tire 1 of this embodiment includes a tread portion 2 for which the mounting orientation on a vehicle is specified. The tread portion 2 includes an outer tread edge 3 located on the outer side of the vehicle when the tire 1 is mounted on the vehicle, and an inner tread edge 4 located on the inner side of the vehicle when the tire 1 is mounted on the vehicle. The mounting orientation on the vehicle is indicated, for example, by letters or symbols on the sidewall portion (not shown).

[0023] In the case of a pneumatic tire, the outer tread edge 3 and the inner tread edge 4 are the axially outermost contact points when the tire 1 in a normal state is loaded with a normal load and contacts the ground on a flat surface with a camber angle of 0°. The normal state refers to a state in which the tire is mounted on a normal rim, inflated to a normal internal pressure, and no load is applied. In this specification, unless otherwise specified, the dimensions of each part of the tire are values ​​measured in the normal state.

[0024] "Genuine rim" is a rim that is specified for each tire by the standard system that includes the standard on which the tire is based. Therefore, a genuine rim is, for example, a "standard rim" for JATMA, a "design rim" for TRA, or a "measuring rim" for ETRTO.

[0025] "Normal internal pressure" is the pressure that is set for each tire by the standard system that includes the standard on which the tire is based. Therefore, normal internal pressure is the "maximum pressure" for JATMA, the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" for TRA, and "INFLATION PRESSURE" for ETRTO.

[0026] The "normal load" is the load that each standard specifies for each tire in the standard system that includes the standard on which the tire is based. Therefore, the normal load is the "maximum load capacity" for JATMA, the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" for TRA, and the "LOAD CAPACITY" for ETRTO. If the tire is for passenger cars, the normal load is the load equivalent to 88% of the above load.

[0027] The tread portion 2 of this embodiment includes a plurality of circumferential grooves 5 that extend continuously in the tire circumferential direction between the outer tread edge 3 and the inner tread edge 4, and a plurality of lateral grooves 6 that extend in a direction intersecting the circumferential grooves 5. Such lateral grooves 6 can form snow pillars in the tire axial direction, and can provide snow traction. The tread portion 2 is also divided into a plurality of land portions 7 by the plurality of circumferential grooves 5. The land portions 7 of this embodiment include a crown land portion 7A, an inner middle land portion 7B, an inner shoulder land portion 7C, an outer middle land portion 7D, and an outer shoulder land portion 7E.

[0028] [Circumferential groove] Each circumferential groove 5 in this embodiment extends linearly in parallel to the tire circumferential direction. However, each circumferential groove 5 may extend in a wavy manner, for example.

[0029] The circumferential grooves 5 include an outer shoulder circumferential groove 5A, an outer crown circumferential groove 5B, an inner crown circumferential groove 5C, and an inner shoulder circumferential groove 5D, arranged in this order from the outer tread edge 3 side to the inner tread edge 4 side.

[0030] The outer shoulder circumferential groove 5A of this embodiment is disposed on the outermost tread edge 3 side among the multiple circumferential grooves 5. The outer crown circumferential groove 5B of this embodiment is disposed between the outer shoulder circumferential groove 5A and the tire equator C. The inner shoulder circumferential groove 5D of this embodiment is disposed on the innermost tread edge 4 side among the multiple circumferential grooves 5. The inner crown circumferential groove 5C of this embodiment is disposed between the inner shoulder circumferential groove 5D and the tire equator C.

[0031] Incidentally, in the above-mentioned circumferential grooves 5A to 5D, air column resonance noise occurs during running on a dry road surface, which tends to affect the pattern noise of the tire 1. Such pattern noise is largely influenced by air column resonance noise generated in the circumferential groove 5 on the side of the outer tread end 3 (i.e., the outer side of the vehicle). Also, the larger the groove width of the circumferential groove 5, the larger the air column resonance noise tends to be.

[0032] In this embodiment, the groove width W1 of the outer shoulder circumferential groove 5A, the groove width W2 of the outer crown circumferential groove 5B, the groove width W3 of the inner crown circumferential groove 5C, and the groove width W4 of the inner shoulder circumferential groove 5D satisfy the following relationship: In this embodiment, the groove widths W1 to W4 are specified as the maximum groove widths of the respective circumferential grooves. W1 <W2<W3<W4

[0033] In the tire 1 of the present embodiment, the circumferential grooves 5A to 5D satisfy the above relationship, so that the air column resonance sound in the circumferential grooves 5 during running can be reduced from the inner tread edge 4 side toward the outer tread edge 3 side, which has a large effect on pattern noise. As a result, the tire 1 can reduce pattern noise.

[0034] On the other hand, in the tire 1 of this embodiment, the groove widths W1-W4 of the circumferential grooves 5A-5D are set to be larger from the outer tread edge 3 side toward the inner tread edge 4 side, which has less effect on pattern noise. This allows the tire 1 to ensure the groove volume of the tread portion 2, thereby maintaining snow traction and drainage performance.

[0035] In order to effectively exert the above-mentioned action, the groove width W1 of the outer shoulder circumferential groove 5A is preferably set to 70% to 90% of the groove width W2 of the outer crown circumferential groove 5B. The groove width W2 of the outer crown circumferential groove 5B is preferably set to 70% to 90% of the groove width W3 of the inner crown circumferential groove 5C. The groove width W3 of the inner crown circumferential groove 5C is preferably set to 70% to 90% of the groove width W4 of the inner shoulder circumferential groove 5D. In this way, each groove width W1 to W4 is set to be gradually smaller from the inner tread edge 4 side toward the outer tread edge 3 side, so that it is possible to prevent the drainage performance and snow traction from deteriorating while reducing pattern noise.

[0036] Each groove width W1 to W4 can be set appropriately as long as it satisfies the above relationship. Each groove width W1 to W4 is set, for example, in the range of 2.0% to 8.0% of the tread width TW. The tread width TW is the distance in the axial direction of the tire between the outer tread edge 3 and the inner tread edge 4.

[0037] Fig. 2 is a cross-sectional view taken along line AA in Fig. 1. As shown in Fig. 2, the groove depth (maximum depth) D1 of each of the circumferential grooves 5A to 5D is set to about 6 to 16 mm. In this embodiment, the groove depth D1 of each of the circumferential grooves 5A to 5D is set to be the same, but similar to the groove widths W1 to W4 shown in Fig. 1, the groove depth D1 may be set to become smaller from the inner tread edge 4 side toward the outer tread edge 3 side. This makes it possible to further reduce pattern noise.

[0038] [Yokomizo] As shown in FIG. 1, the lateral grooves 6 of this embodiment include a plurality of crown lateral grooves 6A, a plurality of inner middle lateral grooves 6B, a plurality of inner shoulder lateral grooves 6C, a plurality of first outer middle lateral grooves 6D, a plurality of second outer middle lateral grooves 6E, and a plurality of outer shoulder lateral grooves 6F.

[0039] [Crown lateral groove] Fig. 3 is a partial enlarged view of the crown land portion 7A and the inner middle land portion 7B. As shown in Fig. 3, each of the crown lateral grooves 6A extends from the inner crown circumferential groove 5C and terminates within the crown land portion 7A. These crown lateral grooves 6A are spaced apart in the tire circumferential direction in the crown land portion 7A. The crown lateral grooves 6A have first openings 11 that open into the inner crown circumferential groove 5C.

[0040] The crown lateral groove 6A of this embodiment can reduce the groove volume compared to, for example, a groove that connects the inner crown circumferential groove 5C and the outer crown circumferential groove 5B, and therefore can reduce pumping noise when the tire touches the ground. Furthermore, the first opening 11 is open on the side of the inner tread edge 4 (shown in FIG. 1) where the effect on pattern noise is small, and therefore pattern noise can be effectively reduced. In addition, the crown lateral groove 6A can pack snow pillars from the first opening 11 toward the inner end 18 in the axial direction of the tire when traveling on snowy roads, and therefore can provide snow traction.

[0041] In this embodiment, the groove width of the crown lateral groove 6A continuously decreases from the first opening 11 toward the inner end 18. This allows the crown lateral groove 6A to more firmly pack snow columns from the first opening 11 toward the inner end 18, thereby providing effective snow traction.

[0042] The maximum groove width W5 of the crown lateral groove 6A is preferably set to about 3.5% to 5.0% of the tread width TW (shown in FIG. 1). As shown in FIG. 2, the groove depth (maximum groove depth) D5 of the crown lateral groove 6A is preferably 50% to 90% of the groove depth D1 (not shown) of the inner crown circumferential groove 5C.

[0043] As shown in FIG. 3, the crown lateral groove 6A of this embodiment is inclined with respect to the tire axial direction. Such crown lateral groove 6A has edge components in the tire circumferential direction and the tire axial direction, so that it can improve snow traction and cornering performance. Furthermore, the crown lateral groove 6A shifts the timing of ground contact and ground exit between the first opening 11 and the inner end 18, so that the air in the crown lateral groove 6A can be gradually released. Therefore, the crown lateral groove 6A can reduce the pumping sound at the time of ground contact and can reduce pattern noise. In order to effectively exert such an effect, the angle θ1 of the crown lateral groove 6A with respect to the tire circumferential direction is preferably 50 to 70°. The angle of each lateral groove 6 is specified by the groove center line of each lateral groove 6.

[0044] [Inner middle groove] Each of the inner middle lateral grooves 6B extends from the inner shoulder circumferential groove 5D to the inner crown circumferential groove 5C. The inner middle lateral grooves 6B are spaced apart in the tire circumferential direction in the inner middle land portion 7B. The inner middle lateral grooves 6B include a second opening 12 opening to the inner crown circumferential groove 5C and a third opening 13 opening to the inner shoulder circumferential groove 5D.

[0045] The inner middle lateral groove 6B communicates between the inner shoulder circumferential groove 5D and the inner crown circumferential groove 5C, so that large snow pillars can be formed in the inner middle land portion 7B. Therefore, the inner middle lateral groove 6B helps to improve snow traction. In addition, the inner middle lateral groove 6B is provided on the side of the inner tread edge 4 (shown in FIG. 1) where the effect on pattern noise is small. Therefore, the inner middle lateral groove 6B can reduce the effect of pumping noise at the time of contact with the ground on pattern noise.

[0046] In order to effectively exert the above-mentioned effects, it is preferable that the maximum groove width W6 of the inner middle lateral groove 6B is set to about 1.5% to 3.5% of the tread width TW (shown in FIG. 1). As shown in FIG. 2, it is preferable that the groove depth (maximum groove depth) D6 of the inner middle lateral groove 6B is 50% to 90% of the groove depth D1 (not shown) of the inner crown circumferential groove 5C.

[0047] 3, the inner middle lateral groove 6B of the present embodiment includes a first portion 21, a second portion 22, and a third portion 23. The first portion 21 extends from the second opening 12 toward the inner shoulder circumferential groove 5D side. On the other hand, the second portion 22 extends from the third opening 13 toward the inner crown circumferential groove 5C side.

[0048] The first portion 21 and the second portion 22 are inclined with respect to the tire circumferential direction. In this embodiment, the first portion 21 and the second portion 22 are inclined with respect to the tire circumferential direction in a direction opposite to the crown lateral groove 6A (directions intersecting each other).

[0049] The third portion 23 connects in a crank shape between the first portion 21 and the second portion 22. The third portion 23 is inclined with respect to the tire circumferential direction.

[0050] The inner middle lateral groove 6B of this embodiment can effectively provide snow traction because it can form crank-shaped snow pillars. In addition, the first portion 21, the second portion 22, and the third portion 23 have edge components in the tire circumferential direction and the tire axial direction, so that it can provide snow traction and cornering performance. Furthermore, the inner middle lateral groove 6B can reduce pumping noise at the time of contact with the ground and can reduce pattern noise. In order to effectively provide such effects, the angle θ2 of the first portion 21 and the second portion 22 with respect to the tire circumferential direction is preferably 50 to 70°. The angle θ3 of the third portion 23 with respect to the tire circumferential direction is preferably 30 to 50°.

[0051] In this embodiment, the first opening 11 of the crown lateral groove 6A is provided at a position different from the second opening 12 in the tire circumferential direction so as not to face the second opening 12 of the inner middle lateral groove 6B. This shifts the timing of the crown lateral groove 6A and the inner middle lateral groove 6B entering and leaving the ground, so that the pumping noise at the time of contact with the ground can be effectively reduced. Therefore, the tire 1 of this embodiment can reduce pattern noise. In order to effectively exert such an effect, the shortest distance L1 in the tire circumferential direction between the first opening 11 and the second opening 12 is preferably 3 to 7% of the tread width TW (shown in FIG. 1). The shortest distance L1 is specified by the intersection 24 between the groove center line of the crown lateral groove 6A and the first opening 11, and the intersection 25 between the groove center line of the inner middle lateral groove 6B and the second opening 12.

[0052] The sum of the maximum groove widths W5 of all the crown lateral grooves 6A and the maximum groove widths W6 of all the inner middle lateral grooves 6B is preferably set to 30% to 40% of the circumference of the tread portion 2 (shown in FIG. 1). By setting the sum of the total values ​​to 30% or more of the circumference, the groove volumes of the crown lateral grooves 6A and the inner middle lateral grooves 6B can be secured, so that snow traction can be exhibited. On the other hand, by setting the sum of the total values ​​to 40% or less of the circumference, an increase in pumping noise can be suppressed. From this viewpoint, the sum of the total values ​​is preferably 32% or more of the circumference, and preferably 38% or less of the circumference. The "circumference of the tread portion" is specified as the tire outer circumferential length at the tire equator C.

[0053] [Inner shoulder groove] Fig. 4 is a partial enlarged view of the inner middle land portion 7B and the inner shoulder land portion 7C. As shown in Fig. 4, each of the inner shoulder lateral grooves 6C extends from the inner shoulder circumferential groove 5D to the inner tread edge 4. These inner shoulder lateral grooves 6C are spaced apart in the tire circumferential direction in the inner middle land portion 7B. The inner shoulder lateral groove 6C includes a fourth opening 14 that opens into the inner shoulder circumferential groove 5D.

[0054] The inner shoulder lateral groove 6C communicates between the inner shoulder circumferential groove 5D and the inner tread edge 4, so that large snow pillars can be formed in the inner shoulder land portion 7C. Therefore, the inner shoulder lateral groove 6C helps to improve snow traction. In addition, the inner shoulder lateral groove 6C is provided on the side of the inner tread edge 4, which has less effect on pattern noise. Therefore, the inner shoulder lateral groove 6C can reduce the effect of pumping noise at the time of contact with the ground on pattern noise.

[0055] In order to effectively exert the above-mentioned effects, it is preferable that the maximum groove width W7 of the inner shoulder lateral groove 6C is set to about 2.0% to 4.0% of the tread width TW (shown in Fig. 1). As shown in Fig. 2, it is preferable that the groove depth (maximum groove depth) D7 (shown in Fig. 2) of the inner middle lateral groove 6B is 50 to 90% of the groove depth D1 (not shown) of the inner shoulder circumferential groove 5D.

[0056] The inner shoulder lateral groove 6C of this embodiment is curved so that the angle θ4 with respect to the tire axial direction continuously decreases from the fourth opening 14 toward the inner tread edge 4. The inner shoulder lateral groove 6C of this embodiment is inclined in the opposite direction (crossing direction) to the inner middle lateral groove 6B (the first portion 21 and the second portion 22 shown in FIG. 3) with respect to the tire circumferential direction. Such an inner shoulder lateral groove 6C can form a large snow pillar extending in the tire axial direction while exerting edge components in the tire circumferential direction and the tire axial direction, so that it can exert snow traction and cornering performance. In order to exert such action effectively, the angle θ4 is desirably set to 5 to 45°.

[0057] In this embodiment, the third opening 13 is provided at a position different from the fourth opening 14 in the tire circumferential direction so as not to face the fourth opening 14. This shifts the timing of the ground contact entry and exit of the inner middle lateral groove 6B and the inner shoulder lateral groove 6C, so that the pumping noise at the time of ground contact can be effectively reduced. Therefore, the tire 1 of this embodiment can reduce pattern noise. In order to effectively exert such an effect, the shortest distance L2 in the tire circumferential direction between the third opening 13 and the fourth opening 14 is preferably 4 to 8% of the tread width TW (shown in FIG. 1). The shortest distance L2 is specified by the intersection 26 between the groove center line of the inner middle lateral groove 6B and the third opening 13, and the intersection 27 between the groove center line of the inner shoulder lateral groove 6C and the fourth opening 14.

[0058] The sum of the maximum groove widths W7 of all the inner shoulder lateral grooves 6C and the maximum groove widths W6 of all the inner middle lateral grooves 6B is preferably set to 20% to 30% of the circumference of the tread portion 2 (shown in FIG. 1). By setting the sum of the total values ​​to 20% or more of the circumference, the groove volumes of the inner shoulder lateral grooves 6C and the inner middle lateral grooves 6B can be secured, so that snow traction can be exhibited. By setting the sum of the total values ​​to 30% or less of the circumference, an increase in pumping noise can be suppressed. From this viewpoint, the sum of the total values ​​is preferably 22% or more of the circumference, and more preferably 28% or less of the circumference.

[0059] [First outer middle groove] Fig. 5 is a partial enlarged view of the outer middle land portion 7D and the outer shoulder land portion 7E. As shown in Fig. 5, each of the first outer middle lateral grooves 6D extends from the outer shoulder circumferential groove 5A and terminates in the outer middle land portion 7D. These first outer middle lateral grooves 6D are spaced apart in the tire circumferential direction in the outer middle land portion 7D. The first outer middle lateral groove 6D has a fifth opening 15 that opens into the outer shoulder circumferential groove 5A.

[0060] The first outer middle lateral groove 6D of this embodiment can have a smaller groove volume than, for example, a groove that connects the outer shoulder circumferential groove 5A and the outer crown circumferential groove 5B. Therefore, the first outer middle lateral groove 6D can reduce the pumping noise at the time of contact with the ground on the outer tread edge 3 side, which has a large effect on pattern noise. In addition, the first outer middle lateral groove 6D can pack snow pillars from the fifth opening 15 toward the axially inner inner end 29 of the tire, thereby providing good snow traction.

[0061] In this embodiment, the groove width of the first outer middle lateral groove 6D continuously decreases from the fifth opening 15 toward the inner end 29. This allows the first outer middle lateral groove 6D to pack snow columns more firmly from the fifth opening 15 toward the inner end 29, thereby providing effective snow traction.

[0062] The maximum groove width W8 of the first outer middle lateral groove 6D is preferably set to about 3.5% to 5.0% of the tread width TW (shown in FIG. 1). As shown in FIG. 2, the groove depth (maximum depth) D8 of the first outer middle lateral groove 6D is preferably 50% to 90% of the groove depth D1 (not shown) of the outer shoulder circumferential groove 5A.

[0063] As shown in FIG. 5, the first outer middle lateral groove 6D of this embodiment is inclined with respect to the tire axial direction. Since such a first outer middle lateral groove 6D has edge components in the tire circumferential direction and the tire axial direction, it can exhibit snow traction and cornering performance. Furthermore, the first outer middle lateral groove 6D can shift the timing of ground contact and ground contact exit between the fifth opening 15 and the inner end 29. As a result, the first outer middle lateral groove 6D can reduce the pumping sound at the time of ground contact on the side of the outer tread edge 3, which has a large effect on pattern noise, and can reduce pattern noise. In order to effectively exhibit such an effect, the angle θ5 of the first outer middle lateral groove 6D with respect to the tire circumferential direction is preferably 50 to 70°.

[0064] [Second outer middle groove] Each of the second outer middle lateral grooves 6E extends from the outer crown circumferential groove 5B and terminates in the outer middle land portion 7D. The second outer middle lateral grooves 6E are spaced apart in the tire circumferential direction in the outer middle land portion 7D. The second outer middle lateral grooves 6E have sixth openings 16 that open into the outer crown circumferential groove 5B.

[0065] The second outer middle lateral groove 6E of this embodiment can have a smaller groove volume than, for example, a groove that connects the outer crown circumferential groove 5B and the outer shoulder circumferential groove 5A. Therefore, the second outer middle lateral groove 6E can reduce the pumping noise at the time of contact with the ground on the side of the outer tread edge 3, which has a large effect on pattern noise. In addition, the second outer middle lateral groove 6E can compact snow pillars from the sixth opening 16 toward the inner end 30 on the axially inner side of the tire, thereby providing good snow traction.

[0066] In this embodiment, the groove width of the second outer middle lateral groove 6E continuously decreases from the sixth opening 16 toward the inner end 30. This allows the second outer middle lateral groove 6E to pack snow columns more firmly from the sixth opening 16 toward the inner end 30, thereby providing effective snow traction.

[0067] The maximum groove width W9 of the second outer middle lateral groove 6E is preferably set in the same range as the maximum groove width W8 of the first outer middle lateral groove 6D. Also, the groove depth (maximum groove depth (not shown)) of the second outer middle lateral groove 6E is preferably set in the same range as the groove depth D8 (shown in FIG. 2) of the first outer middle lateral groove 6D.

[0068] The second outer middle lateral groove 6E of this embodiment is inclined with respect to the tire axial direction. Since such second outer middle lateral groove 6E has edge components in the tire circumferential direction and the tire axial direction, it can exhibit snow traction and cornering performance. Furthermore, the second outer middle lateral groove 6E of this embodiment is arranged parallel to the first outer middle lateral groove 6D. As a result, the second outer middle lateral groove 6E can exhibit edge components in the same direction as the first outer middle lateral groove 6D, which can further improve snow traction and cornering performance.

[0069] The second outer middle lateral groove 6E can shift the timing of ground contact entry and exit between the sixth opening 16 and the inner end 30 by inclining with respect to the tire axial direction. As a result, the second outer middle lateral groove 6E can reduce the pumping noise at the time of ground contact on the outer tread edge 3 side, which has a large effect on pattern noise, and can reduce pattern noise. In order to effectively exert such an effect, it is preferable that the angle θ6 of the second outer middle lateral groove 6E with respect to the tire circumferential direction is set in the same range as the angle θ5 of the first outer middle lateral groove 6D.

[0070] The fifth opening 15 of the first outer middle lateral groove 6D of this embodiment is provided at a position different from the sixth opening 16 of the second outer middle lateral groove 6E in the tire circumferential direction. As a result, the first outer middle lateral groove 6D and the second outer middle lateral groove 6E are alternately spaced apart in the tire circumferential direction, so that the timing of the first outer middle lateral groove 6D and the second outer middle lateral groove 6E entering and leaving the ground can be shifted from each other. As a result, the first outer middle lateral groove 6D and the second outer middle lateral groove 6E can effectively reduce the pumping noise at the time of contact with the ground on the side of the outer tread edge 3, which has a large effect on the pattern noise. Therefore, the tire 1 of this embodiment can reduce the pattern noise.

[0071] [Outer shoulder groove] Each of the outer shoulder lateral grooves 6F extends from the outer tread edge 3 and terminates within the outer shoulder land portion 7E. These outer shoulder lateral grooves 6F are spaced apart in the tire circumferential direction in the outer shoulder land portion 7E. The outer shoulder lateral groove 6F has a seventh opening 17 that opens to the outer tread edge 3.

[0072] The outer shoulder lateral groove 6F can have a smaller groove volume than, for example, a groove that connects the outer tread edge 3 and the outer shoulder circumferential groove 5A. Therefore, the outer shoulder lateral groove 6F can reduce the pumping noise at the time of contact with the ground on the outer tread edge 3 side, which has a large effect on pattern noise. In addition, the outer shoulder lateral groove 6F can pack snow columns from the seventh opening 17 toward the axially inner end 33 of the tire, thereby providing good snow traction.

[0073] In this embodiment, the maximum groove width W10 of the outer shoulder lateral groove 6F is set smaller than the maximum groove width W7 (shown in FIG. 4) of the inner shoulder lateral groove, so that the outer shoulder lateral groove 6F can effectively reduce the pumping noise at the time of contact with the ground on the outer tread edge 3 side, which has a large influence on pattern noise.

[0074] In order to effectively exert the above-mentioned effects, it is desirable that the maximum groove width W10 of the outer shoulder lateral groove 6F is set to about 1.0% to 2.5% of the tread width TW (shown in Fig. 1). As shown in Fig. 2, it is desirable that the groove depth D10 of the outer shoulder lateral groove 6F is 50 to 90% of the groove depth D1 (not shown) of the outer shoulder circumferential groove 5A.

[0075] As shown in Fig. 5, the outer shoulder lateral groove 6F of this embodiment is inclined with respect to the tire axial direction. Furthermore, the outer shoulder lateral groove 6F of this embodiment is inclined in the opposite direction (crossing each other) to the first outer middle lateral groove 6D with respect to the tire circumferential direction. Such outer shoulder lateral groove 6F can form large snow pillars extending in the tire axial direction while exerting edge components in the tire circumferential direction and the tire axial direction, thereby exerting snow traction and cornering performance. In order to effectively exert such effects, it is desirable to set the angle θ6 to 5 to 45°.

[0076] In this embodiment, the first opening 11, the second opening 12, and the third opening 13 shown in Fig. 3, the fourth opening 14 shown in Fig. 4, and the fifth opening 15, the sixth opening 16, and the seventh opening 17 shown in Fig. 5 are provided at different positions in the tire circumferential direction. This allows the timing of ground contact and ground exit of the crown lateral groove 6A, the inner middle lateral groove 6B, the inner shoulder lateral groove 6C, the first outer middle lateral groove 6D, the second outer middle lateral groove 6E, and the outer shoulder lateral groove 6F to be shifted. Therefore, the tire 1 of this embodiment can effectively reduce the pumping sound at the time of contact with the ground and can effectively reduce the pattern noise.

[0077] [Crown Land Division] As shown in Fig. 3, the crown land portion 7A of the present embodiment is divided between the outer crown circumferential groove 5B and the inner crown circumferential groove 5C. The crown land portion 7A is provided with a plurality of crown sipes 36. Such crown sipes 36 can increase the edge components of the crown land portion 7A, thereby improving snow traction.

[0078] In this specification, "sipe" means a cut having a width of less than 1.5 mm. The width of the sipe is more preferably, for example, 0.5 to 1.0 mm. The depth of the sipe (not shown) is set to 30% to 70% of the groove depth D1 (shown in FIG. 2) of the outer crown circumferential groove 5B.

[0079] The crown sipes 36 in this embodiment are configured to include a first crown sipe 36A extending from the inner end 18 of the crown lateral groove 6A to the outer crown circumferential groove 5B, and a second crown sipe 36B extending from the inner crown circumferential groove 5C to the outer crown circumferential groove 5B.

[0080] In this embodiment, the first crown sipes 36A and the second crown sipes 36B are inclined parallel to the crown lateral grooves 6A. These first crown sipes 36A and the second crown sipes 36B have edge components in the tire circumferential direction and the tire axial direction, so that it is possible to improve snow traction and cornering performance. In addition, the first crown sipes 36A can increase the deformation of the crown lateral grooves 6A during running (when in contact with the ground), and can efficiently discharge snow and water, thereby improving snow traction.

[0081] [Inner middle land area] The inner middle land portion 7B is divided between the inner shoulder circumferential groove 5D and the inner crown circumferential groove 5C. In this embodiment, the inner middle land portion 7B is divided into a plurality of inner middle blocks 38 by the inner middle lateral grooves 6B.

[0082] The inner middle block 38 is provided with a plurality of inner middle sipes 39 that communicate between the inner shoulder circumferential groove 5D and the inner crown circumferential groove 5C. Such inner middle sipes 39 can increase the edge component of the inner middle block 38, thereby improving snow traction.

[0083] The inner middle sipe 39 of this embodiment includes a first portion 41, a second portion 42, and a third portion 43, and is formed in a crank shape, similar to the inner middle lateral groove 6B. The first portion 41 is inclined so as to be parallel to the first portion 21 of the inner middle lateral groove 6B. The second portion 42 is inclined so as to be parallel to the second portion 22 of the inner middle lateral groove 6B. The third portion 43 is inclined so as to be parallel to the third portion 23 of the inner middle lateral groove 6B. Such an inner middle sipe 39 can form a crank-shaped edge component together with the inner middle lateral groove 6B, and therefore can effectively exert snow traction.

[0084] In the present embodiment, the inner middle block 38 is provided with a first recess 45 in the sidewall 52 on the inner shoulder circumferential groove 5D side. In the present embodiment, both ends of the first recess 45 in the tire circumferential direction are connected to the inner middle sipes 39, 39. Such a first recess 45 can generate large snow pillars together with the inner shoulder circumferential groove 5D and can prevent the snow pillars from clogging the inner shoulder circumferential groove 5D.

[0085] Furthermore, a chamfered portion 53 is provided at the corner between the side wall 52 of the inner middle block 38 and the inner middle lateral groove 6B. Such a chamfered portion 53 can prevent damage at the corner and also prevent snow pillars from clogging the inner middle lateral groove 6B.

[0086] [Inner shoulder land area] 4, the inner shoulder land portion 7C is divided between the inner shoulder circumferential groove 5D and the inner tread edge 4. The inner shoulder land portion 7C of the present embodiment is divided into a plurality of inner shoulder blocks 47 by the inner shoulder lateral grooves 6C.

[0087] The inner shoulder block 47 is provided with a plurality of inner shoulder sipes 48 extending from the inner shoulder circumferential groove 5D to the inner tread edge 4. Such inner shoulder sipes 48 can increase the edge component of the inner shoulder block 47, thereby improving snow traction.

[0088] In this embodiment, the inner shoulder sipes 48 are inclined with respect to the tire axial direction (parallel to the inner shoulder lateral grooves 6C). Since such inner shoulder sipes 48 have edge components in the tire circumferential direction and the tire axial direction, it is possible to improve snow traction and cornering performance.

[0089] The inner shoulder sipe 48 of this embodiment includes a first portion 48a extending linearly and a second portion 48b extending zigzag. When the second portion 48b touches the ground, the opposing sipe walls of the second portion 48b come into contact with each other so as to mesh with each other, thereby maintaining the rigidity of the inner shoulder land portion 7C and improving snow traction performance.

[0090] In the present embodiment, the inner shoulder block 47 is provided with a second recess 46 on the sidewall 55 on the inner shoulder circumferential groove 5D side. In the present embodiment, both ends of the second recess 46 in the tire circumferential direction are connected to the inner shoulder sipes 48, 48. Such a second recess 46, together with the first recess 45 of the inner middle block 38 and the inner shoulder circumferential groove 5D, can generate large snow pillars and prevent the snow pillars from clogging the inner shoulder circumferential groove 5D. To effectively exert such an effect, it is desirable to provide the second recess 46 at a position different from the first recess 45 in the tire circumferential direction.

[0091] [Outer middle land area] As shown in Fig. 5, the outer middle land portion 7D is divided between the outer shoulder circumferential groove 5A and the outer crown circumferential groove 5B. The outer middle land portion 7D is provided with a plurality of outer middle sipes 50. Such outer middle sipes 50 can increase the edge components of the outer middle land portion 7D, thereby improving snow traction.

[0092] The outer middle sipes 50 of this embodiment include a first outer middle sipe 50A, a second outer middle sipe 50B, and a third outer middle sipe 50C. The first outer middle sipe 50A extends from the inner end 29 of the first outer middle lateral groove 6D to the outer crown circumferential groove 5B. The second outer middle sipe 50B extends from the inner end 30 of the second outer middle lateral groove 6E to the outer shoulder circumferential groove 5A. The third outer middle sipe 50C extends (communicates) from the outer shoulder circumferential groove 5A to the outer crown circumferential groove 5B.

[0093] In this embodiment, the first outer middle sipe 50A, the second outer middle sipe 50B, and the third outer middle sipe 50C are inclined parallel to the first outer middle lateral groove 6D and the second outer middle lateral groove 6E. These first outer middle sipe 50A, the second outer middle sipe 50B, and the third outer middle sipe 50C have edge components in the tire circumferential direction and the tire axial direction, thereby improving snow traction and cornering performance.

[0094] The first outer middle sipe 50A can increase the deformation of the first outer middle lateral groove 6D during running (when the tire is in contact with the ground), and can efficiently discharge snow and water. Furthermore, the second outer middle sipe 50B can increase the deformation of the second outer middle lateral groove 6E during running (when the tire is in contact with the ground), and can efficiently discharge snow and water. Therefore, the first outer middle sipe 50A and the second outer middle sipe 50B can improve snow traction.

[0095] 1, the land ratio of the outer middle land portion 7D is desirably set to 80% to 120% of the land ratio of the inner middle land portion 7B. In this specification, the land ratio is defined as the ratio (S / Sa) of the surface area S of the tread of each land portion 7 to the surface area Sa of the virtual tread obtained by filling all the grooves of each land portion 7.

[0096] By setting the land ratio of the outer middle land portion 7D to 80% or more of the land ratio of the inner middle land portion 7B, the rigidity of the outer middle land portion 7D is maintained, so that snow traction and steering stability can be exhibited. Furthermore, since the land ratio of the outer middle land portion 7D, which has a relatively large effect on pattern noise among the outer middle land portion 7D and the inner middle land portion 7B, can be prevented from becoming small, the ratio of the first outer middle lateral groove 6D and the second outer middle lateral groove 6E can be prevented from becoming large. As a result, the deterioration of snow traction and steering stability is suppressed while reducing pattern noise.

[0097] On the other hand, by setting the land ratio of the outer middle land portion 7D to 120% or less of the land ratio of the inner middle land portion 7B, it is possible to prevent the rigidity of the outer middle land portion 7D from becoming higher than necessary, while preventing a large difference in rigidity between the outer middle land portion 7D and the inner middle land portion 7B. From this perspective, the land ratio of the outer middle land portion 7D is preferably 90% or more and 110% or less of the land ratio of the inner middle land portion 7B.

[0098] [Outer shoulder land area] 5, the outer shoulder land portion 7E is divided between the outer shoulder circumferential groove 5A and the outer tread edge 3. The outer shoulder land portion 7E is provided with a plurality of outer shoulder sipes 51 extending from the outer shoulder circumferential groove 5A to the outer tread edge 3. Such outer shoulder sipes 51 can increase the edge component of the outer shoulder land portion 7E, thereby improving snow traction.

[0099] In this embodiment, the outer shoulder sipes 51 are inclined with respect to the tire axial direction (parallel to the outer shoulder lateral grooves 6F). Since such outer shoulder sipes 51 have edge components in the tire circumferential direction and the tire axial direction, it is possible to improve snow traction and cornering performance.

[0100] The outer shoulder sipe 51 of this embodiment includes a first portion 51a extending linearly and a second portion 51b extending zigzag. When the second portion 51b touches the ground, the opposing sipe walls of the second portion 51b come into contact with each other so as to mesh with each other, so that the rigidity of the outer shoulder land portion 7E can be maintained and the snow traction performance can be improved.

[0101] As shown in FIG. 1, the land ratio of the outer shoulder land portion 7E is preferably set to 100% to 150% of the land ratio of the inner shoulder land portion 7C. By setting the land ratio of the outer shoulder land portion 7E to 100% or more of the land ratio of the inner shoulder land portion 7C, the rigidity of the outer shoulder land portion 7E can be increased, so that snow traction and steering stability can be exhibited. Furthermore, since the land ratio of the outer shoulder land portion 7E, which has a relatively large effect on pattern noise between the outer shoulder land portion 7E and the inner shoulder land portion 7C, can be prevented from becoming small, the proportion of the outer shoulder lateral grooves 6F can be prevented from becoming large. This reduces pattern noise while suppressing a decrease in snow traction and steering stability.

[0102] On the other hand, by setting the land ratio of the outer shoulder land portion 7E to 150% or less of the land ratio of the inner shoulder land portion 7C, it is possible to prevent the rigidity of the outer shoulder land portion 7E from becoming higher than necessary, while preventing the rigidity difference with the inner shoulder land portion 7C from becoming large. From this perspective, the land ratio of the outer shoulder land portion 7E is preferably 110% or more and preferably 140% or less of the land ratio of the inner shoulder land portion 7C.

[0103] Although a particularly preferred embodiment of the present invention has been described in detail above, the present invention is not limited to the illustrated embodiment, and can be modified and carried out in various forms. EXAMPLES

[0104] [Example A] A tire having the basic structure shown in FIG. 1 was prototyped (Examples 1 to 4), in which the groove width W1 of the outer shoulder circumferential groove, the groove width W2 of the outer crown circumferential groove, the groove width W3 of the inner crown circumferential groove, and the groove width W4 of the inner shoulder circumferential groove satisfy the relationship of "W1 < W2 < W3 < W4".

[0105] For comparison, as shown in FIG. 6(a), a tire (Comparative Example 1) in which the groove width of each circumferential groove satisfies the relationship of "W1 = W2 = W3 = W4", and a tire (Comparative Example 2) in which the relationship of "W2 = W3 > W1 = W4" are satisfied were prototyped.

[0106] Then, for each prototyped tire, pattern noise and snow traction were evaluated. The common specifications and test methods are as follows. The test results are shown in Table 1. Tire size: 225 / 65R17 Rim size: 17×6.5J Inner pressure: 230 kPa Vehicle: Four-wheel drive vehicle (engine displacement 2000 cc) Tread width TW: 210 mm Groove depth D1 of each circumferential groove: 8.5 mm Groove depth D5, D7 to D10 of transverse grooves: 6.8 mm Groove depth D6 of transverse groove: 6.0 mm (Sum of maximum groove widths of crown transverse grooves + Sum of maximum groove widths of inner middle transverse grooves) / Circumference of tread portion: 35% (Sum of maximum groove widths of inner shoulder transverse grooves + Sum of maximum groove widths of inner middle transverse grooves) / Circumference of tread portion: 25% Outer middle land ratio / Inner middle land ratio: 100% Outer shoulder land ratio / Inner shoulder land ratio: 110%

[0107] <Resistance to pattern noise performance> After each test tire was mounted on the above rim and filled with the above internal pressure, it was mounted on all the wheels of the above vehicle. Then, when one test driver got on the vehicle and drove on a dry paved road surface, the pattern noise was evaluated by the test driver's sense. The results are represented by an index with Comparative Example 1 as 100. The larger the numerical value, the smaller the pattern noise and the better the noise performance.

[0108] <Snow traction performance> After each test tire was mounted on the above rim and filled with the above internal pressure, it was mounted on all the wheels of the above vehicle. Then, when one test driver got on the vehicle, the distance when accelerating from 5 mph to 20 mph on a snow course was measured. The results are represented by an index with Comparative Example 1 as 100. The larger the numerical value, the better the snow traction.

[0109] [Table 1]

[0110] As a result of the test, the examples were able to reduce pattern noise while maintaining snow traction compared to the comparative examples. Furthermore, Example 1 having misalignments of the first and second openings, misalignments of the third and fourth openings, and misalignments of the fifth and sixth openings was able to significantly reduce pattern noise compared to other examples.

[0111] [Example B] Tires having the basic structure shown in FIG. 1 were prototyped based on the specifications in Table 2 (Examples 1, 5 to 12). These examples satisfy the relationship of "W1 < W2 < W3 < W4" for the groove width W1 of the outer shoulder circumferential groove, the groove width W2 of the outer crown circumferential groove, the groove width W3 of the inner crown circumferential groove, and the groove width W4 of the inner shoulder circumferential groove. The common specifications and test methods are as follows. Also, the test results are shown in Table 2. The common specifications are the same as those of Example A except for the following specifications and the specifications in Table 2.

[0112] [Table 2]

[0113] As a result of the tests, in Preferred Examples 1, 6, and 7, in which the ratio of the sum of the maximum groove widths of the crown lateral grooves and the inner middle lateral grooves to the circumference of the tread portion is favorable, it was possible to achieve both maintenance of snow traction and reduction of pattern noise, as compared with other Examples 5 and 8. Further, in Preferred Examples 1, 10, and 11, in which the ratio of the sum of the maximum groove widths of the inner shoulder lateral grooves and the inner middle lateral grooves to the circumference of the tread portion is favorable, it was possible to achieve both maintenance of snow traction and reduction of pattern noise, as compared with other Examples 9 and 12.

[0114] [Example C] Tires having the basic structure shown in FIG. 1 were prototyped based on the specifications in Table 3 (Examples 1, 13 to 20). In these examples, the groove width W1 of the outer shoulder circumferential groove, the groove width W2 of the outer crown circumferential groove, the groove width W3 of the inner crown circumferential groove, and the groove width W4 of the inner shoulder circumferential groove satisfy the relationship of "W1 < W2 < W3 < W4". The common specifications and test methods are as follows. Also, the test results are shown in Table 3. The common specifications are the same as those of Example A, except for the following specifications and the specifications in Table 3.

[0115] [Table 3]

[0116] As a result of the tests, in Preferred Examples 1, 14, and 15, in which the ratio of the land ratio of the outer middle land portion to the land ratio of the inner middle land portion is favorable, it was possible to achieve both maintenance of snow traction and reduction of pattern noise, as compared with other Examples 13 and 16. Furthermore, in Preferred Examples 1, 18, and 19, in which the ratio of the land ratio of the outer shoulder land portion to the land ratio of the inner shoulder land portion is favorable, it was possible to achieve both maintenance of snow traction and reduction of pattern noise, as compared with other Examples 17 and 20. [Explanation of Signs]

[0117] 1 Tire 2 Tread section 3 Outer tread edge 4 Inner tread edge 5 Circumferential groove 5A Outer shoulder circumferential groove 5B Outer crown circumferential groove 5C Inner crown circumferential groove 5D inner shoulder circumferential groove

Claims

1. A tire, Includes a tread section that is specified for installation on a vehicle, the tread portion includes an outer tread edge located on an outer side of the vehicle when the tire is mounted on the vehicle, an inner tread edge located on an inner side of the vehicle when the tire is mounted on the vehicle, a plurality of circumferential grooves extending continuously in a tire circumferential direction between the outer tread edge and the inner tread edge, and a plurality of lateral grooves extending in a direction intersecting the circumferential grooves, the circumferential grooves are comprised of an outer shoulder circumferential groove, an outer crown circumferential groove, an inner crown circumferential groove, and an inner shoulder circumferential groove, which are arranged in this order from the outer tread end side to the inner tread end side, a groove width W1 of the outer shoulder circumferential groove, a groove width W2 of the outer crown circumferential groove, a groove width W3 of the inner crown circumferential groove, and a groove width W4 of the inner shoulder circumferential groove satisfy the following relationship: W1<W2<W3<W4 the tread portion includes an inner middle land portion partitioned between the inner shoulder circumferential groove and the inner crown circumferential groove, the lateral grooves include a plurality of inner middle lateral grooves extending from the inner shoulder circumferential groove to the inner crown circumferential groove, the tread portion includes a crown land portion partitioned between the outer crown circumferential groove and the inner crown circumferential groove, The lateral grooves include a plurality of crown lateral grooves, Each of the crown lateral grooves extends from the inner crown circumferential groove and terminates within the crown land portion, a sum of a total value of a maximum groove width of all the crown lateral grooves and a total value of a maximum groove width of all the inner middle lateral grooves is 30% to 40% of a circumferential length of the tread portion. tire.

2. The crown lateral groove includes a first opening that opens into the inner crown circumferential groove, the inner middle lateral groove includes a second opening portion that opens into the inner crown circumferential groove, The tire according to claim 1 , wherein the first opening is provided at a position different from the second opening in the tire circumferential direction so as not to face the second opening.

3. The tread portion includes an inner shoulder land portion partitioned between the inner shoulder circumferential groove and the inner tread edge, The tire according to claim 1 or 2, wherein the lateral grooves include a plurality of inner shoulder lateral grooves extending from the inner shoulder circumferential groove to the inner tread edge.

4. The inner middle lateral groove includes a third opening that opens into the inner shoulder circumferential groove, the inner shoulder lateral groove includes a fourth opening portion that opens into the inner shoulder circumferential groove, The tire according to claim 3 , wherein the third opening is provided at a position different from the fourth opening in the tire circumferential direction so as not to face the fourth opening.

5. A tire as described in claim 3 or 4, wherein the sum of the total maximum groove width of all of the inner shoulder lateral grooves and the total maximum groove width of all of the inner middle lateral grooves is 20% to 30% of the circumference of the tread portion.

6. The tread portion includes an outer middle land portion partitioned between the outer shoulder circumferential groove and the outer crown circumferential groove, The tire according to claim 1 , wherein the lateral grooves include a plurality of first outer middle lateral grooves extending from the outer shoulder circumferential groove and terminated within the outer middle land portion.

7. The tire as described in claim 6, wherein the lateral grooves include a plurality of second outer middle lateral grooves extending from the outer crown circumferential groove and terminating within the outer middle land portion.

8. The first outer middle lateral groove includes a fifth opening that opens into the outer shoulder circumferential groove, the second outer middle lateral groove includes a sixth opening portion that opens into the outer crown circumferential groove, The tire according to claim 7 , wherein the fifth opening is provided at a position different from the sixth opening in the tire circumferential direction.

9. The tread portion includes an outer middle land portion partitioned between the outer shoulder circumferential groove and the outer crown circumferential groove, and an inner middle land portion partitioned between the inner shoulder circumferential groove and the inner crown circumferential groove, 9. The tire according to claim 1, wherein a land ratio of the outer middle land portion is 80% to 120% of a land ratio of the inner middle land portion.

10. The tread portion includes an outer shoulder land portion partitioned between the outer shoulder circumferential groove and the outer tread edge, and an inner shoulder land portion partitioned between the inner shoulder circumferential groove and the inner tread edge, The tire according to any one of claims 1 to 9, wherein a land ratio of the outer shoulder land portion is 100% to 150% of a land ratio of the inner shoulder land portion.

Images