tire

Abstract

To provide a tire which can keep and show excellent on-snow turning performance.SOLUTION: A tire is given with a tread part 2. The tread part 2 includes: two circumferential grooves 3; and a first land part 10. The first land part 10 includes a plurality of blocks 18 which are separated by a plurality of lateral grooves 20. The lateral groove 20 includes: a first inclined part 21 which extends from one of the two circumferential grooves 3 to the side of the first tire circumferential direction regarding a tire axial direction; a second inclined part 22 which extends from the other of the two circumferential grooves 3 to the side of the first tire circumferential direction regarding the tire axial direction; and a connection part 23 which is arranged between the first inclined part 21 and the second inclined part 22. A circumferential short groove 24 extending from the connection part 23 to the first tire circumferential direction is arranged at at least one of the plurality of blocks 18.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] The following Patent Document 1 proposes a pneumatic tire having a plurality of shoulder lateral grooves in the shoulder land portion and a plurality of first middle lateral grooves in the first middle land portion. The shoulder lateral grooves and the first middle lateral grooves are expected to maintain the performance on icy roads and improve the performance on snow. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-013514 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned tires, snow can get stuck in the grooves, and there is still room for improvement in terms of turning performance on snow.

[0005] The present invention has been devised in view of the above circumstances, and has as its main object to provide a tire that can continuously exhibit excellent cornering performance on snow. [Means for solving the problem]

[0006] The present invention is a tire having a tread portion, the tread portion including at least two circumferential grooves extending continuously in a tire circumferential direction between two tread ends, and a first land portion divided between the two circumferential grooves, the first land portion including a plurality of blocks divided into a plurality of lateral grooves completely crossing the first land portion in the tire axial direction, the lateral groove including a first inclined portion extending from one of the two circumferential grooves toward the first tire circumferential side in the tire axial direction, a second inclined portion extending from the other of the two circumferential grooves toward the first tire circumferential side in the tire axial direction, and a connection portion between the first inclined portion and the second inclined portion, and at least one of the plurality of blocks is provided with a circumferential short groove extending in the first tire circumferential direction from the connection portion.

[0007] In the tire of the present invention, it is preferable that an angle of the first inclined portion with respect to the tire axial direction be larger than an angle of the second inclined portion with respect to the tire axial direction.

[0008] In the tire of the present invention, it is preferable that the length of the first inclined portion in the tire axial direction is smaller than the length of the second inclined portion in the tire axial direction.

[0009] In the tire of the present invention, it is preferable that each of the two circumferential grooves has a plurality of variable width portions in which the groove width changes in the tire circumferential direction, and that the variable width portion of one of the circumferential grooves has a groove width that continuously decreases in the first tire circumferential direction.

[0010] In the tire of the present invention, it is preferable that each of the two circumferential grooves has a plurality of variable width portions in which the groove width changes in the tire circumferential direction, and that the variable width portion of the other circumferential groove has a groove width that continuously increases in the first tire circumferential direction.

[0011] In the tire of the present invention, it is preferable that the block is provided with an interrupted lateral groove extending in the tire axial direction from the other circumferential groove and interrupted within the block.

[0012] In the tire of the present invention, it is preferable that the circumferential short groove and the interrupted lateral groove each have an interrupted end within the block, and the interrupted end of the interrupted lateral groove is located on the side of the other circumferential groove relative to the interrupted end of the circumferential short groove.

[0013] In the tire of the present invention, it is preferable that the first inclined portion crosses the tire equator.

[0014] In the tire of the present invention, it is preferable that the tread portion has a specified orientation when mounted on a vehicle, and that the one circumferential groove is positioned on the outer side of the vehicle than the other circumferential groove when mounted on the vehicle.

[0015] In the tire of the present invention, it is preferable that the tread portion includes five land portions divided by four of the circumferential grooves. Effect of the Invention

[0016] By adopting the above-mentioned configuration, the tire of the present invention can continuously exhibit excellent cornering performance on snow. [Brief description of the drawings]

[0017] [Figure 1] 1 is a development view of a tread portion of a tire according to one embodiment of the present invention. [Diagram 2] FIG. 2 is an enlarged view of a first land portion in FIG. [Diagram 3] FIG. 3 is an enlarged view of the lateral grooves and blocks of FIG. 2. [Figure 4] 2 is an enlarged view of an outer middle land portion, a crown land portion, and an inner middle land portion of FIG. [Diagram 5] FIG. 2 is an enlarged view of the inner shoulder land portion of FIG. [Figure 6] FIG. 2 is an enlarged view of the outer shoulder land portion of FIG. [Figure 7] FIG. 4 is an enlarged view of a first land portion of a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a development view of a tread portion 2 of a tire 1 of this embodiment. As shown in Fig. 1, the tire 1 of this embodiment is used, for example, as a pneumatic tire for passenger cars intended for use in winter. However, the tire 1 of the present invention is not limited to such an embodiment.

[0019] The tire 1 of this embodiment has a tread portion 2 in which the mounting direction on a vehicle is specified, for example. The mounting direction on a vehicle is indicated, for example, by characters or marks on the sidewall portion (not shown). In addition, the tread portion 2 is configured, for example, in an asymmetric pattern (meaning that the tread pattern is not line-symmetric with respect to the tire equator C).

[0020] The tread portion 2 includes two tread ends. The tread portion 2 of this embodiment includes a first tread end T1 that is on the outer side of the vehicle when mounted on the vehicle, and a second tread end T2 that is on the inner side of the vehicle when mounted on the vehicle. The first tread end T1 and the second tread end T2 each correspond to the axially outermost contact positions when the tire 1 in a normal state is loaded with a normal load and touches the ground on a flat surface with a camber angle of 0°.

[0021] "Normal condition" means, in the case of a pneumatic tire for which various standards are established, that the tire is mounted on a normal rim, inflated to the normal internal pressure, and no load is applied. In the case of a tire for which various standards are not established or a non-pneumatic tire, the normal condition means a standard use condition according to the intended use of the tire, and a state in which no load is applied. In this specification, unless otherwise specified, the dimensions of each part of the tire are values ​​measured in the normal condition.

[0022] A "genuine rim" is a rim that is defined for each tire by the standard system that includes the standard on which the tire is based. For example, in the case of JATMA, it is called a "standard rim," in the case of TRA, it is called a "Design Rim," and in the case of ETRTO, it is called a "Measuring Rim."

[0023] "Normal internal pressure" is the air pressure set for each tire by each standard in the standard system on which the tire is based. In the case of JATMA, it is the "maximum air pressure." In the case of TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES." In the case of ETRTO, it is the "INFLATION PRESSURE."

[0024] In the case of a pneumatic tire for which various standards are established, the "normal load" is the load that each standard specifies for each tire in the standard system including the standard on which the tire is based. For JATMA, it is the "maximum load capacity", for TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES", and for ETRTO, it is the "LOAD CAPACITY". In addition, in the case of a tire for which various standards are not established or a non-pneumatic tire, the "normal load" refers to the load acting on one tire in the standard mounting state of the tire. The "standard mounting state" refers to a state in which the tire is mounted on a standard vehicle according to the intended use of the tire, and the vehicle is stationary on a flat road surface in a drivable state.

[0025] The tread portion 2 includes at least two circumferential grooves 3 extending continuously in the tire circumferential direction between the first tread edge T1 and the second tread edge T2. The tread portion 2 of this embodiment includes four circumferential grooves 3. As a result, the tire 1 of this embodiment is configured as a so-called five-rib tire including five land portions 8 divided into the four circumferential grooves 3. However, the tire 1 of the present invention is not limited to this aspect, and may be, for example, a so-called four-rib tire in which the tread portion 2 is configured with three circumferential grooves 3 and four land portions 8.

[0026] The circumferential grooves 3 include, for example, an outer crown circumferential groove 5, an inner crown circumferential groove 6, an outer shoulder circumferential groove 4, and an inner shoulder circumferential groove 7. The outer crown circumferential groove 5 is provided on the first tread edge T1 side of the tire equator C. The inner crown circumferential groove 6 is provided on the second tread edge T2 side of the tire equator C. The outer shoulder circumferential groove 4 is provided between the outer crown circumferential groove 5 and the first tread edge T1. The inner shoulder circumferential groove 7 is provided between the inner crown circumferential groove 6 and the second tread edge T2.

[0027] The circumferential groove 3 may have various configurations such as a configuration extending linearly in the tire circumferential direction, a configuration extending in a zigzag pattern, etc. A specific configuration of the circumferential groove 3 of this embodiment will be described later.

[0028] The axial distance L1 from the groove centerline of the outer shoulder circumferential groove 4 or the inner shoulder circumferential groove 7 to the tire equator C is, for example, 20% to 35% of the tread width TW. The axial distance L2 from the groove centerline of the outer crown circumferential groove 5 or the inner crown circumferential groove 6 to the tire equator C is, for example, 3% to 15% of the tread width TW. The tread width TW is the axial distance from the first tread edge T1 to the second tread edge T2 in the normal state.

[0029] The groove width W1 of the circumferential groove 3 is desirably at least 3 mm. In a preferred embodiment, the groove width W1 of the circumferential groove 3 is 2.0% to 6.0% of the tread width TW. In this embodiment, of the four circumferential grooves 3, the inner crown circumferential groove 6 has the largest groove width.

[0030] The land portion 8 includes, for example, an outer shoulder land portion 11, an outer middle land portion 12, a crown land portion 13, an inner middle land portion 14, and an inner shoulder land portion 15. The outer shoulder land portion 11 is located axially outward of the outer shoulder circumferential groove 4, and includes a first tread edge T1. The outer middle land portion 12 is located between the outer shoulder circumferential groove 4 and the outer crown circumferential groove 5. The crown land portion 13 is located between the outer crown circumferential groove 5 and the inner crown circumferential groove 6. The inner middle land portion 14 is located between the inner shoulder circumferential groove 7 and the inner crown circumferential groove 6. The inner shoulder land portion 15 is located axially outward of the inner shoulder circumferential groove 7, and includes a second tread edge T2.

[0031] In the present invention, the tire includes a first land portion 10 defined between the two circumferential grooves 3. In this embodiment, the outer crown circumferential groove 5 and the inner crown circumferential groove 6 correspond to the two circumferential grooves 3, and the crown land portion 13 corresponds to the first land portion 10. Therefore, the configuration of the two circumferential grooves 3 described below can be applied to the outer crown circumferential groove 5 or the inner crown circumferential groove 6. Similarly, the configuration of the first land portion 10 can be applied to the crown land portion 13.

[0032] Fig. 2 shows an enlarged view of the two circumferential grooves 3 and the first land portion 10. As shown in Fig. 2, the first land portion 10 includes a plurality of blocks 18 divided into a plurality of lateral grooves 20 that completely cross the first land portion 10 in the tire axial direction.

[0033] FIG. 3 shows an enlarged view of the lateral groove 20 and the block 18. As shown in FIG. 3, the lateral groove 20 includes a first inclined portion 21, a second inclined portion 22, and a connection portion 23. The first inclined portion 21 extends from one of the two circumferential grooves 3 (in this embodiment, the outer crown circumferential groove 5) toward the first tire circumferential direction (corresponding to the upward direction in each drawing of this specification) with respect to the tire axial direction. The second inclined portion 22 extends from the other of the two circumferential grooves 3 (in this embodiment, the inner crown circumferential groove 6) toward the first tire circumferential direction with respect to the tire axial direction. The connection portion 23 is disposed between the first inclined portion 21 and the second inclined portion 22 and communicates with them. Hereinafter, in this specification, the same inclination direction as the first inclined portion 21 may be referred to as "inclined in the first direction with respect to the tire axial direction". Also, the same inclination direction as the second inclined portion 22 may be referred to as "inclined in the second direction with respect to the tire axial direction".

[0034] In the present invention, at least one of the blocks 18 is provided with a circumferential short groove 24 extending in the first tire circumferential direction from a connecting portion 23. By adopting the above-mentioned configuration, the tire of the present invention can continuously exhibit excellent cornering performance on snow. The following mechanism is presumed to be the reason for this.

[0035] When driving on snow, the tire 1 of the present invention can generate a large snow column shear force by forming hard snow columns with the two circumferential grooves 3 and the lateral grooves 20 and shearing them. In particular, in the present invention, the block 18 is provided with the circumferential short grooves 24 extending from the connection parts 23 in the first tire circumferential direction, so that the snow can be strongly compacted near the circumferential short grooves 24 due to changes in ground contact pressure, generating a larger snow column shear force.

[0036] In addition, the circumferential short grooves 24 can provide a large reaction force in the axial direction of the tire by their edges and the snow pillars they create, thereby improving cornering performance on snow.

[0037] Furthermore, the above-mentioned lateral grooves 20 and circumferential short grooves 24 are prone to change in groove shape due to changes in ground pressure. Therefore, the lateral grooves 20 and circumferential short grooves 24 can strongly pack snow within the contact area when traveling on snow, while actively discharging the snow inside when the snow leaves the contact area. It is believed that this mechanism allows the present invention to continuously demonstrate excellent cornering performance on snow.

[0038] A more detailed configuration of this embodiment will be described below. Each configuration described below shows a specific aspect of this embodiment. Therefore, it goes without saying that the present invention can achieve the above-mentioned effects even if it does not have the configuration described below. In addition, even if any one of the configurations described below is applied alone to the tire of the present invention having the above-mentioned characteristics, an improvement in performance according to each configuration can be expected. Furthermore, when some of the configurations described below are applied in combination, a composite improvement in performance according to each configuration can be expected.

[0039] As shown in Fig. 2, of the two circumferential grooves 3, the maximum groove width of one circumferential groove 3 is smaller than the maximum groove width of the other circumferential groove 3. This provides a good balance between driving stability on dry roads (hereinafter, sometimes simply referred to as "driving stability") and turning performance on snow. In this embodiment, the one circumferential groove 3 communicates with the first inclined portion 21 of the lateral groove 20 and corresponds to the outer crown circumferential groove 5. The other circumferential groove 3 communicates with the second inclined portion 22 of the lateral groove 20 and corresponds to the inner crown circumferential groove 6.

[0040] Each of the two circumferential grooves 3 has a plurality of variable width portions 26 in the circumferential direction of the tire, in which the groove width changes in the circumferential direction of the tire. The angle between two edges included in the variable width portions 26 is, for example, 3 to 8°. Such variable width portions 26 can pack snow inside by utilizing the rotation of the tire when traveling on snow.

[0041] The width of the variable width portion 26a of the one circumferential groove 3 is continuously reduced in the circumferential direction of the first tire. The width of the variable width portion 26b of the other circumferential groove 3 is continuously increased in the circumferential direction of the first tire. This allows solid snow pillars to be formed during both traction and braking on snow. This improves traction and braking performance when driving on snow.

[0042] The maximum groove width W2 of the lateral groove 20 is desirably larger than the maximum groove width of the one circumferential groove 3. Also, the maximum groove width W2 of the lateral groove 20 is desirably smaller than the maximum groove width of the other circumferential groove 3. Such a lateral groove 20 improves the driving stability and the performance on snow in a well-balanced manner.

[0043] As shown in FIG. 3, the angle θ1 of the first inclined portion 21 with respect to the tire axial direction is, for example, 20 to 40°. The angle θ2 of the second inclined portion 22 with respect to the tire axial direction is, for example, 15 to 25°. In a more preferable embodiment, the angle θ1 of the first inclined portion 21 is larger than the angle θ2 of the second inclined portion 22. However, it is preferable that the difference between the angle θ1 and the angle θ2 is, for example, 15° or less. Such first inclined portion 21 and second inclined portion 22 exhibit different deformation modes when in contact with the ground, and can actively discharge snow from the lateral grooves 20 when traveling on snow.

[0044] The axial length L3 of the first inclined portion 21 and the axial length L4 of the second inclined portion 22 are, for example, 30% to 70% of the maximum axial width W3 of the first land portion 10 (shown in FIG. 2, and the same applies below). The lengths L3 and L4 are defined by the groove center line 20c of the lateral groove 20. That is, the lengths L3 and L4 correspond to the axial length of the groove center line 20c from one or the other circumferential groove 3 to the connection portion 23, respectively.

[0045] It is desirable that the length L3 in the tire axial direction of the first inclined portion 21 is smaller than the length L4 in the tire axial direction of the second inclined portion 22. However, it is desirable that the length L3 is 80% or more of the length L4. Such first inclined portion 21 and second inclined portion 22 can suppress uneven wear of the first land portion 10 while suppressing snow from clogging inside the lateral groove 20.

[0046] In order to further exert the above-mentioned effects, in this embodiment, the first land portion 10 is disposed on the tire equator C, and further, the first inclined portion 21 crosses the tire equator C.

[0047] In this embodiment, the first inclined portion 21 and the second inclined portion 22 are connected, and the connection portion 23 is configured as a bent portion of the lateral groove 20. However, the present invention is not limited to this embodiment, and the connection portion 23 may extend in the tire axial direction to some extent. In this case, the length of the connection portion 23 in the tire axial direction is, for example, 5% to 40% of the width W3 (shown in FIG. 2) of the first land portion 10 in the tire axial direction.

[0048] The circumferential short groove 24 has a discontinuous end 24a that terminates within the tread surface of the block 18. In a preferred embodiment, the circumferential short groove 24 has a groove width that continuously decreases toward the discontinuous end 24a. The maximum groove width of the circumferential short groove 24 is, for example, 40% to 60% of the maximum groove width W2 (shown in FIG. 2) of the lateral groove 20. Such a circumferential short groove 24 can improve cornering performance on snow while maintaining steering stability.

[0049] The circumferential short grooves 24 extend in the first tire circumferential direction from the lateral grooves 20 and terminate before the tire circumferential center position of the block 18. The tire circumferential length L6 of the circumferential short grooves 24 is, for example, 5% to 20% of the tire circumferential length L5 (shown in FIG. 2) of the block 18. Such circumferential short grooves 24 improve steering stability and on-snow performance in a well-balanced manner.

[0050] In this embodiment, the block 18 is provided with one interrupted lateral groove 25. The interrupted lateral groove 25 extends in the tire axial direction from the other circumferential groove 3 and has an interrupted end 25a that terminates within the block 18. Such an interrupted lateral groove 25 is useful for improving on-snow traction performance while maintaining steering stability.

[0051] The interrupted end 25a of the interrupted lateral groove 25 is located, for example, on the other circumferential groove 3 side of the tire equator C, and preferably on the other circumferential groove 3 side of the axial center position of the block 18. In a more preferable embodiment, the interrupted end 25a of the interrupted lateral groove 25 is located on the other circumferential groove 3 side of the interrupted end 24a of the circumferential short groove 24.

[0052] In addition, in a plan view of the tread, it is preferable that a virtual area obtained by extending the entirety of the interrupted lateral grooves 25 parallel to the tire axial direction does not overlap with the circumferential short grooves 24. Such an arrangement of the circumferential short grooves 24 and the interrupted lateral grooves 25 can suppress uneven wear of the blocks 18 while achieving the above-mentioned effects.

[0053] The interrupted lateral grooves 25 are, for example, inclined in the second direction with respect to the tire axial direction. The angle of the interrupted lateral grooves 25 with respect to the tire axial direction is, for example, 15 to 25°. In this embodiment, the angle difference between the interrupted lateral grooves 25 and the second inclined portion 22 is 10° or less, and in a more preferable embodiment, they are arranged in parallel. This allows the interrupted lateral grooves 25 and the second inclined portion 22 to work together to improve the traction performance and cornering performance on snow.

[0054] The interrupted lateral grooves 25 extend with a constant groove width W4, for example, except for the communicating portion with the other circumferential groove 3. The groove width W4 of the interrupted lateral grooves 25 is, for example, 10% to 30% of the maximum groove width W2 of the lateral grooves 20. In a preferred embodiment, the groove width W4 of the interrupted lateral grooves 25 is smaller than the maximum groove width of the circumferential short grooves 24. Such interrupted lateral grooves 25 improve the traction performance on snow while suppressing uneven wear of the blocks 18.

[0055] The block 18 is provided with a plurality of sipes 28. A "sipe" refers to a cut element having a minute width, and the width between two sipe walls facing each other is 0.6 mm or less. The width of the sipe is preferably 0.1 to 0.5 mm, and more preferably 0.2 to 0.4 mm. The sipe of this embodiment extends with a constant width over its entire depth. The sipe may be a chamfered portion that opens with a width larger than the width, or a flask bottom portion that is larger than the width.

[0056] The sipes 28 extend, for example, in a wavy manner in a plan view of the tread. The sipes 28 may be configured, for example, as so-called 3D sipes that extend wavy in the depth direction as well. Such sipes 28 can increase the rigidity of the blocks 18 when the opposing sipe walls come into contact with each other, and can improve performance on snow while maintaining steering stability. The above configuration of the sipes 28 can also be applied to sipes provided in other land portions.

[0057] For example, the sipes 28 are inclined in the second direction with respect to the tire axial direction, which makes it easier for the blocks 18 to fall in a direction that expels snow from the first inclined portions 21 when traveling on snow, thereby making it possible to prevent snow from clogging the lateral grooves 20.

[0058] 4 shows an enlarged view of the outer middle land portion 12, the crown land portion 13, and the inner middle land portion 14. As shown in FIG. 4, the inner middle land portion 14 includes a plurality of inner middle blocks 31 separated by a plurality of inner middle lateral grooves 30.

[0059] The inner middle lateral groove 30 extends, for example, with a constant groove width W5 and completely crosses the inner middle land portion 14. The groove width W5 of the inner middle lateral groove 30 is, for example, 70% to 90% of the maximum groove width W2 of the lateral groove 20 provided in the first land portion 10.

[0060] The inner middle lateral grooves 30 are inclined in the first direction with respect to the tire axial direction, for example. The angle of the inner middle lateral grooves 30 with respect to the tire axial direction is, for example, 15 to 25 degrees.

[0061] In a more preferable embodiment, the region where the end of the inner middle lateral groove 30 on the inner crown circumferential groove 6 side is extended parallel to the tire axial direction toward the tire equator C should overlap with the end of the lateral groove 20 on the inner crown circumferential groove 6 side. Such inner middle lateral groove 30 cooperates with the lateral groove 20 to form a hard snow pillar, further improving on-snow performance.

[0062] The inner middle block 31 is provided with a lateral narrow groove 32 having a groove width and groove depth smaller than those of the inner middle lateral groove 30. The lateral narrow groove 32 is inclined, for example, in the first direction with respect to the tire axial direction. The angle of the lateral narrow groove 32 with respect to the tire axial direction is, for example, 15 to 25 degrees, and in this embodiment, the lateral narrow groove 32 and the inner middle lateral groove 30 are arranged parallel to each other.

[0063] The inner middle block 31 is divided into a first block piece 31a and a second block piece 31b by the above-mentioned lateral narrow groove 32. The first block piece 31a and the second block piece 31b are each provided with a plurality of inner middle sipes 34 inclined with respect to the tire axial direction.

[0064] The inner middle sipes 34 are inclined in the first direction with respect to the tire axial direction, for example. The inner middle sipes 34 include, for example, a full-open sipe 34a that crosses the inner middle block 31 in the tire axial direction, and a semi-open sipe 34b that extends from the inner shoulder circumferential groove 7 or the inner crown circumferential groove 6 and terminates within the inner middle block 31.

[0065] In a preferred embodiment, the first block piece 31a is provided with a dimple 35 between the semi-open sipe 34b and the inner shoulder circumferential groove 7. The dimple 35 is recessed in an area surrounded by an edge of an ellipse that is elongated in the tire circumferential direction. Such a dimple 35 can moderately reduce the rigidity of the inner middle block 31 and prevent snow from clogging the surrounding grooves.

[0066] The outer middle land portion 12 includes a plurality of outer middle blocks 44 divided into a plurality of outer middle lateral grooves 40 that completely traverse the outer middle land portion 12 in the tire axial direction.

[0067] The outer middle lateral groove 40 includes a first groove portion 41 extending in the tire axial direction at the first tread edge T1 side, and a second groove portion 42 extending in the tire axial direction at the second tread edge T2 side. The second groove portion 42 is shifted to one side in the tire circumferential direction with respect to the first groove portion 41, so that the outer middle lateral groove 40 includes two longitudinal edges 43 extending in the tire circumferential direction between the edge 41a of the first groove portion 41 and the edge 42a of the second groove portion 42. The outer middle lateral groove 40 including such longitudinal edges 43 can improve both the traction performance on snow and the cornering performance on snow.

[0068] The outer middle lateral grooves 40 are inclined in the first direction with respect to the tire axial direction. In a more preferable embodiment, an imaginary area obtained by extending the second groove portion 42 of the outer middle lateral grooves 40 along its length toward the tire equator C overlaps with an end portion of the first inclined portion 21 on the outer crown circumferential groove 5 side. Such outer middle lateral grooves 40 can form solid snow pillars in cooperation with the first inclined portion 21 when driving on snow.

[0069] The outer middle block 44 is provided with an interrupted groove 45 that extends from the outer shoulder circumferential groove 4 and has an interrupted end 45a within the outer middle block 44. In the present invention, the interrupted end 45a of the interrupted groove 45 is located closer to the outer shoulder circumferential groove 4 than the two longitudinal edges 43. Such an interrupted groove 45 improves driving stability and on-snow performance in a well-balanced manner.

[0070] In this embodiment, the outer middle block 44 is provided with a dimple 46 between the outer middle lateral groove 40 and the interrupted groove 45. This dimple 46 is recessed in an area surrounded by an edge of an ellipse that is elongated in the tire circumferential direction. This type of dimple 46 moderately reduces the rigidity of the outer middle block 44 and can prevent snow from clogging the surrounding grooves.

[0071] The outer middle block 44 is provided with a plurality of outer middle sipes 47. The outer middle sipes 47 are inclined in the first direction with respect to the tire axial direction. The outer middle sipes 47 of the present embodiment extend from the outer shoulder circumferential groove 4 or the outer crown circumferential groove 5, and have a discontinued end within the outer middle block 44.

[0072] Fig. 5 shows an enlarged view of the inner shoulder land portion 15. As shown in Fig. 5, the inner shoulder land portion 15 is provided with a plurality of inner shoulder lateral grooves 50 and a plurality of inner shoulder interrupted grooves 51.

[0073] The inner shoulder lateral groove 50 crosses, for example, the inner shoulder land portion 15 in the tire axial direction. The inner shoulder lateral groove 50 of the present embodiment includes, for example, a first inclined groove portion 50a extending from the inner shoulder circumferential groove 7 at an incline in the first direction with respect to the tire axial direction, and a second inclined groove portion 50b continuing to the first inclined groove portion 50a and extending at an incline in the second direction with respect to the tire axial direction. Such an inner shoulder lateral groove 50 improves the traction performance on snow and the cornering performance on snow in a well-balanced manner.

[0074] The inner shoulder interrupted groove 51 communicates with the inner shoulder circumferential groove 7 and has an interrupted end 51a within the inner shoulder land portion 15. In this embodiment, the inner shoulder interrupted groove 51 includes a portion extending along the first inclined groove portion 50a and a portion extending along the second inclined groove portion 50b. Such an inner shoulder interrupted groove 51 suppresses uneven wear of the inner shoulder land portion 15 while improving performance on snow and on ice.

[0075] The inner shoulder land portion 15 includes a plurality of inner shoulder blocks 52 that are divided into a plurality of inner shoulder lateral grooves 50. The inner shoulder blocks 52 are provided with a plurality of inner shoulder sipes 53.

[0076] 6 shows an enlarged view of the outer shoulder land portion 11. As shown in FIG. 6, the outer shoulder land portion 11 includes, for example, a plurality of outer shoulder blocks 56 separated by a plurality of outer shoulder lateral grooves 55.

[0077] The outer shoulder lateral groove 55 includes, for example, an inner groove portion 55a and an outer groove portion 55b. The inner groove portion 55a communicates, for example, with the outer shoulder circumferential groove 4 and is inclined in the first direction with respect to the tire axial direction. The outer groove portion 55b communicates, for example, with the first tread edge T1 side of the inner groove portion 55a and is inclined in the second direction with respect to the tire axial direction. The outer shoulder lateral groove 55 including such inner groove portion 55a and outer groove portion 55b improves the traction performance on snow and the cornering performance on snow in a well-balanced manner.

[0078] The outer shoulder block 56 is provided with a plurality of outer shoulder sipes 57. The outer shoulder sipes 57 include, for example, a first outer shoulder sipe 57a extending along the inner groove portion 55a of the outer shoulder lateral groove 55 and a second outer shoulder sipe 57b extending along the outer groove portion 55b of the outer shoulder lateral groove 55. Such outer shoulder sipes 57 can provide frictional forces in multiple directions, improving traction performance and cornering performance on snow.

[0079] Although the tire according to one embodiment of the present invention has been described in detail above, the present invention is not limited to the above specific embodiment and can be modified and carried out in various aspects. EXAMPLES

[0080] A tire of size 195 / 65R15 having the basic tread pattern of FIG. 1 was prototyped based on the specifications of Table 1. As a comparative example, a tire having a first land portion a shown in FIG. 7 was prototyped. As shown in FIG. 7, the block b of the first land portion a of the comparative example does not have a circumferential short groove. The comparative example tire has substantially the same pattern as that shown in FIG. 1, except for the above-mentioned configuration. Each test tire was tested for steering stability on dry roads, traction performance on snow, and cornering performance on snow. The common specifications and test methods of each test tire are as follows. Rim: 15×6.0JJ Tire pressure: front wheel 200kPa, rear wheel 200kPa Test vehicle: 2000cc, front-wheel drive Tire mounting position: All wheels

[0081] <Steering stability on dry roads> The driving stability of the test vehicle when it was driven on a dry road surface was evaluated by the driver. The results are expressed as a score based on the comparative example being 100, with a higher score indicating better driving stability on a dry road surface.

[0082] <Traction performance on snow> The traction performance of the test vehicle when it was driven on snow was evaluated by the driver. The results are given as a score based on the comparative example being 100, with a higher score indicating better traction performance on snow.

[0083] <Turning performance on snow> The cornering performance of the test vehicle on snow was evaluated by the driver. The results are given as a score based on the comparative example being 100, with the higher the score, the better the cornering performance on snow. The test results are shown in Table 1.

[0084] [Table 1]

[0085] As shown in Table 1, it was confirmed that the tires of the examples exhibited excellent turning performance on snow. In addition, it was confirmed that the tires of the examples maintained a driving stability of 98 to 100 points on dry roads, and improved traction performance on snow of 101 to 106 points. [Explanation of symbols]

[0086] 2 Tread section 3 Circumferential groove 10 1st Land Department 18 blocks 20 Yokomizo 21 1st slope 22 2nd slope part 23 Connection 24 Circumferential short groove

Claims

1. A tire having a tread portion, The tread portion includes at least two circumferential grooves extending continuously in a tire circumferential direction between two tread ends, and a first land portion partitioned between the two circumferential grooves, The first land portion includes a plurality of blocks divided into a plurality of lateral grooves that completely cross the first land portion in the tire axial direction, the lateral groove includes a first inclined portion extending from one of the two circumferential grooves toward a first tire circumferential side in the tire axial direction, a second inclined portion extending from the other of the two circumferential grooves toward the first tire circumferential side in the tire axial direction, and a connection portion between the first inclined portion and the second inclined portion, At least one of the plurality of blocks is provided with a circumferential short groove extending from the connection portion in the first tire circumferential direction, The length of the first inclined portion in the tire axial direction is shorter than the length of the second inclined portion in the tire axial direction. tire.

2. The tire according to claim 1 , wherein an angle of the first inclined portion with respect to the tire axial direction is larger than an angle of the second inclined portion with respect to the tire axial direction.

3. The tire according to claim 1 or 2, wherein a length in the tire axial direction of the first inclined portion is 80% or more of a length in the tire axial direction of the second inclined portion.

4. Each of the two circumferential grooves has a plurality of width-changing portions in which the groove width changes in the tire circumferential direction, The tire according to claim 1 , wherein the variable width portion of the one circumferential groove has a groove width that continuously decreases in the first tire circumferential direction.

5. Each of the two circumferential grooves has a plurality of width-changing portions in which the groove width changes in the tire circumferential direction, The tire according to claim 1 , wherein the variable width portion of the other circumferential groove has a groove width that continuously increases in the first tire circumferential direction.

6. The tire according to claim 1 , wherein the block is provided with an interrupted lateral groove that extends in the tire axial direction from the other circumferential groove and is interrupted within the block.

7. The circumferential short groove and the interrupted lateral groove each have an interrupted end within the block, The tire according to claim 6 , wherein the interrupted end of the interrupted lateral groove is located on a side of the other circumferential groove with respect to the interrupted end of the circumferential short groove.

8. 8. The tire according to claim 1, wherein the first inclined portion transverses the tire equator.

9. The tread portion has a specified orientation for installation on a vehicle, The tire according to claim 1 , wherein the one circumferential groove is located on an outer side of the vehicle than the other circumferential groove when the tire is mounted on the vehicle.

10. The tire according to claim 1 , wherein the tread portion includes five land portions divided by four of the circumferential grooves.

11. A tire having a tread portion, The tread portion includes at least two circumferential grooves extending continuously in a tire circumferential direction between two tread ends, and a first land portion partitioned between the two circumferential grooves, The first land portion includes a plurality of blocks divided into a plurality of lateral grooves that completely cross the first land portion in the tire axial direction, the lateral groove includes a first inclined portion extending from one of the two circumferential grooves toward a first tire circumferential side in the tire axial direction, a second inclined portion extending from the other of the two circumferential grooves toward the first tire circumferential side in the tire axial direction, and a connection portion between the first inclined portion and the second inclined portion, At least one of the plurality of blocks is provided with a circumferential short groove extending from the connection portion in the first tire circumferential direction, The block is provided with an interrupted lateral groove that extends in the tire axial direction from the other circumferential groove and is interrupted within the block, The circumferential short groove and the interrupted lateral groove each have an interrupted end within the block, The interrupted end of the interrupted lateral groove is located closer to the other circumferential groove than the interrupted end of the circumferential short groove. tire.

12. A tire having a tread portion, The tread portion includes at least two circumferential grooves extending continuously in a tire circumferential direction between two tread ends, and a first land portion partitioned between the two circumferential grooves, The first land portion includes a plurality of blocks divided into a plurality of lateral grooves that completely cross the first land portion in the tire axial direction, the lateral groove includes a first inclined portion extending from one of the two circumferential grooves toward a first tire circumferential side in the tire axial direction, a second inclined portion extending from the other of the two circumferential grooves toward the first tire circumferential side in the tire axial direction, and a connection portion between the first inclined portion and the second inclined portion, At least one of the plurality of blocks is provided with a circumferential short groove extending from the connection portion in the first tire circumferential direction, The first inclined portion intersects the tire equator. tire.

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