阅读说明：本技术 轮胎 (Tyre for vehicle wheels ) 是由 八木健太 西村圭司 于 2021-05-25 设计创作，主要内容包括：本发明提供使冰上的制动性能和转弯性能提高的轮胎。轮胎具有指定向车辆安装的朝向的胎面部(2)。外侧胎肩陆地部(11)被外侧胎肩横沟(18)划分为多个外侧胎肩花纹块(20)。外侧胎肩花纹块(20)中的至少一个被第1纵细沟(19)划分为第1花纹块片(21)和第2花纹块片(22)。在第1花纹块片(21)设置有多个第1刀槽(23)。在第2花纹块片(22)设置有多个第2刀槽(24)。第2花纹块片(22)的第2刀槽(24)的总条数大于第1花纹块片(21)的第1刀槽(23)的总条数。(The invention provides a tire which improves braking performance and turning performance on ice. The tire has a tread portion (2) that specifies a direction of installation to a vehicle. The outer shoulder land portion (11) is divided into a plurality of outer shoulder blocks (20) by outer shoulder lateral grooves (18). At least one of the outer shoulder blocks (20) is divided into a 1 st block piece (21) and a 2 nd block piece (22) by a 1 st longitudinal groove (19). A plurality of 1 st sipes (23) are provided in the 1 st block piece (21). A plurality of 2 nd sipes (24) are provided in the 2 nd block piece (22). The total number of the 2 nd sipes (24) of the 2 nd block piece (22) is larger than the total number of the 1 st sipes (23) of the 1 st block piece (21).)

1. A tire having a tread portion with an orientation designated for mounting to a vehicle,

the tread portion includes: an outer tread end located on an outer side of the vehicle when mounted on the vehicle, an inner tread end located on an inner side of the vehicle when mounted on the vehicle, a plurality of circumferential grooves continuously extending in a tire circumferential direction, and a plurality of land portions divided by the plurality of circumferential grooves,

the plurality of land portions including an outboard shoulder land portion including the outboard tread end,

the outer shoulder land portion is divided into a plurality of outer shoulder blocks by a plurality of outer shoulder lateral grooves extending in the tire axial direction,

at least one of the plurality of outer shoulder blocks is divided into a 1 st block piece on the outer tread end side and a 2 nd block piece on the inner tread end side by a 1 st longitudinal groove extending in the tire circumferential direction,

the 1 st block piece is provided with a plurality of 1 st sipes,

the 2 nd block piece is provided with a plurality of 2 nd sipes,

the total number of the 2 nd sipes of the 2 nd block piece is greater than the total number of the 1 st sipes of the 1 st block piece.

2. The tire according to claim 1, wherein,

the plurality of 1 st sipes and the plurality of 2 nd sipes are each arranged at an angle of 10 ° or less with respect to the tire axial direction.

3. The tire according to claim 1 or 2,

the 1 st vertical narrow groove is arranged in a central region where the outer shoulder block is equally divided by 3 times in the tire axial direction.

4. A tire according to any one of claims 1 to 3,

the 1 st longitudinal groove is curved at least at 1.

5. Tire according to any one of claims 1 to 4,

the depth of the 1 st cutter groove and the depth of the 2 nd cutter groove are larger than the depth of the 1 st longitudinal fine groove.

6. A tire according to any one of claims 1 to 5,

the maximum width of the 2 nd block piece in the tire axial direction is 40% -60% of the maximum width of the outer shoulder block in the tire axial direction.

7. A tire according to any one of claims 1 to 6,

the 1 st cutter groove and the 2 nd cutter groove are respectively provided with a lacing wire with a raised bottom.

8. The tire according to claim 7,

the depth of the part provided with the lacing wire is larger than that of the 1 st longitudinal fine groove.

9. A tire according to any one of claims 1 to 8,

the plurality of land portions including an inboard shoulder land portion including the inboard tread end,

the inner shoulder land portion is divided into a plurality of inner shoulder blocks by a plurality of inner shoulder lateral grooves extending in the tire axial direction,

the maximum width of the inner shoulder pattern block in the tire axial direction is smaller than the maximum width of the outer shoulder pattern block in the tire axial direction.

10. Tire according to any one of claims 1 to 9,

the plurality of land portions including an inboard shoulder land portion including the inboard tread end,

the inner shoulder land portion is divided into a plurality of inner shoulder blocks by a plurality of inner shoulder lateral grooves extending in the tire axial direction,

at least one of the plurality of inner shoulder blocks is provided with a 2 nd vertical thin groove extending in the tire circumferential direction,

the depth of the 2 nd longitudinal fine groove is greater than that of the 1 st longitudinal fine groove.

11. Tire according to any one of claims 1 to 10,

the plurality of land portions including an inboard shoulder land portion including the inboard tread end,

the inner shoulder land portion is divided into a plurality of inner shoulder blocks by a plurality of inner shoulder lateral grooves extending in the tire axial direction,

at least one of the plurality of inner shoulder blocks is divided into a 3 rd block piece on the inner tread end side and a 4 th block piece on the outer tread end side by a 2 nd longitudinal groove extending in the tire circumferential direction,

a plurality of the 3 rd sipes are arranged on the 3 rd block piece,

a plurality of 4 th sipes are arranged on the 4 th block piece,

the total number of the 4 th sipes of the 4 th block piece is the same as the total number of the 3 rd sipes of the 3 rd block piece.

12. Tire according to any one of claims 1 to 11,

the plurality of circumferential grooves include an outer shoulder circumferential groove disposed at a position closest to the outer tread end side,

the outboard shoulder circumferential groove has a minimum groove width among the plurality of circumferential grooves.

13. Tire according to any one of claims 1 to 12,

the maximum groove width of the part of the outer shoulder transverse groove facing the 1 st block piece is larger than the maximum groove width of the part of the outer shoulder transverse groove facing the 2 nd block piece.

Technical Field

The present invention relates to a tire.

Background

Patent document 1 listed below proposes a pneumatic tire in which cornering performance and limit behavior during cornering on icy and snowy roads are improved in a balanced manner by specifying pattern elements of a tread portion.

Patent document 1: japanese patent laid-open publication No. 2013-237360

In recent years, with the increase in vehicle performance, tires intended for winter use are required to have further improved braking performance and cornering performance on ice.

Disclosure of Invention

The present invention has been made in view of the above circumstances, and a main object thereof is to provide a tire that improves braking performance and cornering performance on ice.

The present invention is a tire having a tread portion that specifies an orientation for mounting to a vehicle, wherein the tread portion includes: an outer tread end located on an outer side of a vehicle when mounted on the vehicle, an inner tread end located on an inner side of the vehicle when mounted on the vehicle, a plurality of circumferential grooves continuously extending in a tire circumferential direction, and a plurality of land portions partitioned by the plurality of circumferential grooves, the plurality of land portions including an outer-shoulder land portion including the outer tread end, the outer-shoulder land portion being partitioned into a plurality of outer-shoulder blocks by a plurality of outer-shoulder lateral grooves extending in a tire axial direction, at least one of the plurality of outer-shoulder blocks being partitioned into a 1 st block piece on the outer tread end side and a 2 nd block piece on the inner tread end side by a 1 st longitudinal fine groove extending in the tire circumferential direction, the 1 st block piece being provided with a plurality of 1 st sipes, the 2 nd block piece being provided with a plurality of 2 nd sipes, the total number of the 2 nd sipes of the 2 nd block piece is greater than the total number of the 1 st sipes of the 1 st block piece.

In the tire according to the present invention, it is preferable that the plurality of 1 st sipes and the plurality of 2 nd sipes are each disposed at an angle of 10 ° or less with respect to the tire axial direction.

In the tire of the present invention, it is preferable that the 1 st vertical sipe is disposed in a central region where the outer shoulder block is equally divided by 3 times in the tire axial direction.

Preferably, in the tire of the present invention, the 1 st vertical sipe is curved at least at 1 point.

In the tire according to the present invention, it is preferable that the depth of the 1 st sipe and the depth of the 2 nd sipe are greater than the depth of the 1 st vertical sipe.

In the tire according to the present invention, it is preferable that the maximum width of the 2 nd block piece in the tire axial direction is 40% to 60% of the maximum width of the outer shoulder block in the tire axial direction.

In the tire according to the present invention, it is preferable that each of the 1 st sipe and the 2 nd sipe has a tie bead having a raised bottom.

In the tire according to the present invention, it is preferable that the portion where the tie bar is provided has a depth larger than the depth of the 1 st vertical groove.

Preferably, in the tire according to the present invention, the plurality of land portions include an inner-shoulder land portion including the inner-tread end, the inner-shoulder land portion is divided into a plurality of inner-shoulder blocks by a plurality of inner-shoulder lateral grooves extending in the tire axial direction, and a maximum width of the inner-shoulder blocks in the tire axial direction is smaller than a maximum width of the outer-shoulder blocks in the tire axial direction.

Preferably, in the tire according to the present invention, the plurality of land portions include an inner-shoulder land portion including the inner-tread end, the inner-shoulder land portion is divided into a plurality of inner-shoulder blocks by a plurality of inner-shoulder lateral grooves extending in the tire axial direction, at least one of the plurality of inner-shoulder blocks is provided with a 2 nd vertical groove extending in the tire circumferential direction, and the depth of the 2 nd vertical groove is greater than the depth of the 1 st vertical groove.

In the tire according to the present invention, it is preferable that the plurality of land portions include an inner-shoulder land portion including the inner-tread end, the inner-shoulder land portion is divided into a plurality of inner-shoulder blocks by a plurality of inner-shoulder lateral grooves extending in the tire axial direction, at least one of the plurality of inner-shoulder blocks is divided into a 3 rd block piece on the inner-tread end side and a 4 th block piece on the outer-tread end side by a 2 nd vertical groove extending in the tire circumferential direction, the 3 rd block piece is provided with a plurality of 3 rd sipes, the 4 th block piece is provided with a plurality of 4 th sipes, and the total number of the 4 th sipes of the 4 th block piece is equal to the total number of the 3 rd sipes of the 3 rd block piece.

Preferably, in the tire according to the present invention, the plurality of circumferential grooves include an outer shoulder circumferential groove disposed closest to the outer tread end side, and the outer shoulder circumferential groove has a smallest groove width among the plurality of circumferential grooves.

In the tire according to the present invention, it is preferable that a maximum groove width of a portion of the outer-shoulder lateral groove facing the 1 st block piece is larger than a maximum groove width of a portion of the outer-shoulder lateral groove facing the 2 nd block piece.

The pneumatic tire according to the present invention can improve braking performance and cornering performance on ice by adopting the above configuration.

Drawings

Fig. 1 is a development view of a tread portion of a tire according to an embodiment of the present invention.

Fig. 2 is an enlarged view of the outboard shoulder land portion and the outboard middle land portion of fig. 1.

Fig. 3 is a sectional view taken along line a-a of fig. 2.

Fig. 4 is an enlarged view of the inboard shoulder land portion of fig. 1.

Fig. 5 is an enlarged view of the inboard intermediate land portion and the crown land portion of fig. 1.

Fig. 6 is an enlarged view of an outer shoulder land portion of the tire of the comparative example.

Description of the reference numerals

2 … tread portion; 3 … circumferential grooves; 4 … land portion; 11 … outboard shoulder land portions; 18 … outboard shoulder cross grooves; 19 …, 1 st longitudinal groove; 20 … outboard shoulder blocks; 21 … pattern piece 1; 22 … pattern piece 2; 23 … sipe 1; 24 … No. 2 sipe; to … outer tread end; ti … inboard tread end.

Detailed Description

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

Fig. 1 is a developed view of a tread portion 2 of a tire 1 of the present embodiment. As shown in fig. 1, the tire 1 of the present embodiment is used as a pneumatic tire for a car, which is assumed to be used in winter, for example. However, the tire 1 of the present invention is not limited to such an embodiment.

The tire 1 of the present embodiment has, for example, a tread portion 2 in a direction designated for mounting to a vehicle. For example, the direction of attachment to the vehicle is indicated by characters or symbols on the sidewall portion (not shown).

The tread portion 2 is composed of 4 circumferential grooves 3 continuously extending in the tire circumferential direction between an outer tread end To and an inner tread end Ti, and 5 land portions 4 divided by the circumferential grooves 3. That is, the tire 1 of the present invention is configured as a so-called 5-rib tire. However, the tire 1 of the present invention is not limited to such an embodiment, and may be a so-called 4-rib tire including 3 circumferential grooves 3 and 4 land portions 4.

The outer tread end To is a tread end intended To be located on the outer side of the vehicle when mounted on the vehicle, and the inner tread end Ti is a tread end intended To be located on the inner side of the vehicle when mounted on the vehicle. The outer tread end To and the inner tread end Ti correspond To the tire axial outermost ground contact positions when the tire 1 in a normal state is loaded with a normal load and ground on a plane at a 0 ° camber angle, respectively.

The "normal state" is a state in which, when pneumatic tires of various specifications are specified, the tires are assembled on a normal rim and the normal internal pressure and no load are applied. When tires of various specifications and non-pneumatic tires are not specified, the normal state refers to a standard usage state according to the purpose of use of the tires, and is a state in which the tire is not mounted on a vehicle and is unloaded. In the present specification, unless otherwise specified, the dimensions of each portion of the tire and the like are values measured in the above-described normal state. In addition, the respective structures described in the present specification allow for usual errors included in rubber molded articles.

The "regular Rim" is a Rim that is specified for each tire in a specification system including specifications to which the tire conforms, and for example, JATMA indicates "standard Rim", TRA indicates "Design Rim", and ETRTO indicates "Measuring Rim".

The "normal internal PRESSURE" is an air PRESSURE that is specified for each TIRE in a specification system including specifications that the TIRE conforms to, and indicates "maximum air PRESSURE" in the case of JATMA, a maximum value described in a table "TIRE LOAD conditions AT TIREs cool stability requirements" in the case of TRA, and indicates "stability requirements" in the case of ETRTO.

The "normal LOAD" is a LOAD that is specified for each TIRE in a specification system including specifications to which the TIRE conforms when pneumatic TIREs of VARIOUS specifications are specified, and indicates "maximum LOAD CAPACITY" in the case of JATMA, a maximum value described in a table "TIRE LOAD conditions AT vehicles color stability requirements" in the case of TRA, and "LOAD CAPACITY" in the case of ETRTO. In the case where tires of various specifications or non-pneumatic tires are not specified, the "normal load" refers to a load acting on one tire in a normal use state of the tire. The "standard use state" refers to a state in which a tire is mounted on a standard vehicle according to the purpose of use of the tire and is stationary on a flat road surface in a state in which the vehicle can run.

The circumferential grooves 3 include, for example, an outer shoulder circumferential groove 5, an outer crown circumferential groove 6, an inner crown circumferential groove 7, and an inner shoulder circumferential groove 8. The outer shoulder circumferential groove 5 is provided on the outermost tread end To side among the plurality of circumferential grooves 3. The outer crown circumferential groove 6 is provided between the outer shoulder circumferential groove 5 and the tire equator C, adjacent to the inner tread end Ti of the outer shoulder circumferential groove 5. The inner crown circumferential groove 7 is provided between the tire equator C and the inner tread end Ti. An inboard shoulder circumferential groove 8 is provided between the inboard crown circumferential groove 7 and the inboard tread end Ti.

The circumferential groove 3 may be formed in various forms such as a linear form extending in the tire circumferential direction or a zigzag form extending. In the present embodiment, the outer shoulder circumferential groove 5, the inner crown circumferential groove 7, and the inner shoulder circumferential groove 8 extend linearly in parallel in the tire circumferential direction. On the other hand, the outer crown circumferential groove 6 extends in a zigzag shape. However, the tire 1 of the present invention is not limited to such an embodiment.

The distance L1 in the tire axial direction from the groove center line of the outer shoulder circumferential groove 5 or the inner shoulder circumferential groove 8 to the tire equator C is, for example, 20% to 35% of the tread width TW. The distance L2 in the tire axial direction from the groove center line of the outer crown circumferential groove 6 or the inner crown circumferential groove 7 to the tire equator C is, for example, 3% to 15% of the tread width TW. In a preferred embodiment, the distance in the tire axial direction from the groove center line of the inner crown circumferential groove 7 to the tire equator C is greater than the distance in the tire axial direction from the groove center line of the outer crown circumferential groove 6 to the tire equator C. The tread width TW is a distance in the tire axial direction from the outer tread end To the inner tread end Ti in the normal state.

The groove width W1 of the circumferential groove 3 is preferably at least 3 mm. In a preferred embodiment, the groove width W1 of the circumferential groove 3 is 2.0% to 5.0% of the tread width TW. In the present embodiment, of the 4 circumferential grooves 3, the outer shoulder circumferential groove 5 has the smallest groove width.

The land portion 4 includes an outer shoulder land portion 11, an outer middle land portion 12, a crown land portion 15, an inner middle land portion 14, and an inner shoulder land portion 13. The outer shoulder land portion 11 includes an outer tread end To. The outer intermediate land portion 12 is divided between the outer shoulder circumferential groove 5 and the outer crown circumferential groove 6. The crown land portion 15 is divided between the outer crown circumferential groove 6 and the inner crown circumferential groove 7. The inboard intermediate land portion 14 is divided between the inboard shoulder circumferential groove 8 and the inboard crown circumferential groove 7. The inboard shoulder land portion 13 includes an inboard tread end Ti.

An enlarged view of the outboard shoulder land portion 11 and the outboard middle land portion 12 is shown in fig. 2. As shown in fig. 2, the outer shoulder land portion 11 is divided into a plurality of outer shoulder blocks 20 by a plurality of outer shoulder lateral grooves 18 extending in the tire axial direction.

At least one of the outer shoulder blocks 20 is divided into a 1 st block piece 21 on the outer tread end To side and a 2 nd block piece 22 on the inner tread end Ti side by a 1 st longitudinal groove 19 extending in the tire circumferential direction.

The 1 st block piece 21 is provided with a plurality of 1 st sipes 23. In addition, the 2 nd block piece 22 is provided with a plurality of 2 nd sipes 24.

In the present specification, the "sipe" refers to a grooving element having a minute width, and the width between two opposing sipe walls is 0.6mm or less. The width of the cutter groove is preferably 0.1 to 0.5mm, and more preferably 0.2 to 0.4 mm. The sipe of the present embodiment has the above width in the above range over the entire depth thereof. In the present specification, a notch element having a width of 0.6mm or less occupying 50% or more of the entire depth in a cross section of a certain notch element is treated as a sipe (a sipe including a groove element) even if a region having a width exceeding 0.6mm is partially included. In addition, in the cross section of a certain notch element, a notch element having a region with a width greater than 0.6mm occupying 50% or more of the entire depth is treated as a groove (including a groove of a sipe element) even if a region with a width of 0.6mm or less is partially included.

In the present invention, the total number N2 of the 2 nd sipes 24 arranged in one 2 nd block piece 22 is greater than the total number N1 of the 1 st sipes 23 arranged in one 1 st block piece 21. The pneumatic tire according to the present invention can improve braking performance and cornering performance on ice by adopting the above configuration. The reason for this is assumed to be the following mechanism.

In order To prevent the blocks from collapsing during braking on ice, the number of sipes on the outer tread end To side in the outer shoulder blocks 20 is preferably small. On the other hand, during cornering at normal speed on ice, the lateral acceleration G tends to be smaller than during running on a dry road surface, and the maximum length of the ground contact surface tends to be formed in a region of the tread surface of the outer shoulder land portion 11 that is relatively inward of the tire axial direction. In the present invention, it is assumed that: by making the total number N2 of the 2 nd sipes 24 larger than the total number N1 of the 1 st sipes 23, it is possible to prevent the above-described collapse of the blocks, and to arrange a large number of sipes in the above-described region, thereby improving the braking performance and cornering performance on ice.

Hereinafter, a more detailed configuration of the present embodiment will be described. Each configuration described below represents a specific embodiment of the present embodiment. Therefore, it is needless to say that the present invention can exhibit the above-described effects without having the configuration described below. Further, even if any one of the respective configurations described below is applied to the tire of the present invention having the above-described features alone, improvement in performance according to the respective configurations can be expected. Further, when a plurality of the respective configurations described below are applied in a combined manner, it is possible to expect an improvement in the performance of the combination according to the respective configurations.

The width W2 in the tire axial direction of the outer shoulder blocks 20 is, for example, 15% to 30% of the tread width TW (as shown in fig. 1, the same applies hereinafter). However, the present invention is not limited to such an embodiment.

The outer shoulder lateral groove 18 extends at an angle θ 1 of 10 ° or less with respect to the tire axial direction, for example. The outer-shoulder lateral groove 18 includes a main body portion 18a communicating with the outer-shoulder circumferential groove 5, and a widened portion 18b connected To the outer-tread end To side of the main body portion 18 a. The main body portion 18a has a length of 50% or more of the entire length of the outer shoulder lateral groove 18, for example. Further, the groove width W3 of the main body portion 18a is larger than the groove width W4 of the outer shoulder circumferential groove 5. The widened portion 18b has, for example, a groove width W5 larger than the main body portion 18 a. The groove width W5 of the widened portion 18b is 103% to 110% of the groove width W3 of the body portion 18 a. Thus, the maximum groove width of the portion of the outer shoulder lateral groove 18 facing the 1 st block piece 21 is larger than the maximum groove width of the portion of the outer shoulder lateral groove 18 facing the 2 nd block piece 22. Such an outer shoulder lateral groove 18 contributes to the exertion of excellent on-snow performance.

The 1 st vertical sipe 19 is disposed in a central region where the outer shoulder block 20 is equally divided by 3 times in the tire axial direction, for example. The distance between the groove center line of the 1 st vertical narrow groove 19 and the center position of the outer shoulder block 20 in the tire axial direction is 10% or less of the width W2 of the outer shoulder block 20 in the tire axial direction. The 1 st vertical sipe 19 communicates with the main body portion 18a of the outer shoulder lateral groove 18. Thus, the maximum width of the 2 nd block 22 in the tire axial direction is 40% to 60% of the maximum width of the outer shoulder block 20 in the tire axial direction.

The 1 st longitudinal groove 19 is curved at least at 1. The 1 st vertical groove 19 of the present embodiment is bent at two places to form obtuse angles. Such a 1 st longitudinal groove 19 provides frictional force in a plurality of directions on ice. In the present specification, the term "groove bend" refers to a form in which the length of a region including at least a groove center line curve is 3mm or less.

The width W6 of the 1 st vertical fine groove 19 is larger than 0.6 mm. The groove width W6 is, for example, 0.8 to 2.0mm, preferably 1.0 to 1.5 mm. The depth of the 1 st vertical groove 19 is, for example, 1.5 to 3.0 mm. Such a 1 st sipe 19 improves cornering performance on ice while maintaining rigidity of the outer shoulder block 20.

The total number N1 of the 1 st sipes 23 of the present embodiment is, for example, 3 to 5. The total number N2 of the 2 nd sipes 24 is, for example, 4 to 6. From the viewpoint of suppressing uneven wear of the 1 st block piece 21 and the 2 nd block piece 22, the total number N2 is preferably 1.10 to 2.50 times the total number N1. However, the present invention is not limited to such an embodiment.

For the 1 st sipe 23 and the 2 nd sipe 24, the tire axial component is greater than the tire circumferential component. It is preferable that the 1 st sipe 23 and the 2 nd sipe 24 each cross each block piece in the tire axial direction. In the present embodiment, the 1 st sipe 23 and the 2 nd sipe 24 are each arranged at an angle of 10 ° or less with respect to the tire axial direction. In the case where each sipe extends in a zigzag shape, the angle is measured on an imaginary line connecting both ends of the sipe. Further, the 1 st sipe 23 and the 2 nd sipe 24 are arranged substantially parallel to the outer shoulder lateral groove 18. Here, the substantially parallel state means a state in which the angle difference between the sipe and the lateral groove is 5 ° or less. In addition, in the 1 st block piece 21 and the 2 nd block piece 22, sipes having a tire circumferential component larger than a tire axial component are not provided. Thereby, the traction performance and the braking performance on ice are further improved.

At least 1 of the 1 st sipe 23 and the 2 nd sipe 24 extends in a zigzag shape in the longitudinal direction thereof. In a preferred embodiment, at least 1 of the 1 st sipe 23 and the 2 nd sipe 24 is formed as a so-called 3D sipe extending in a zigzag shape in the depth direction thereof. Such 1 st and 2 nd sipes 23 and 24 suppress excessive collapse of the blocks when the mutually opposing sipe walls contact each other, thereby improving braking performance on ice.

Preferably, at least the sipe adjacent to the outer shoulder lateral groove 18 among the plurality of 1 st sipes 23 and the plurality of 2 nd sipes 24 arranged in the tire circumferential direction is configured as a 3D sipe. In a more preferred aspect, in the present embodiment, all sipes provided in the outboard shoulder blocks 20 are configured as 3D sipes. This reliably exerts the above-described effects.

Fig. 3 is a sectional view taken along line a-a of the 1 st sipe 23 in fig. 2, illustrating the structure of the 1 st sipe 23 and the 2 nd sipe 24. Further, the structure of the 1 st sipe 23 described below can also be applied to the 2 nd sipe 24. In fig. 3, the bent portion of the 1 st sipe 23 configured as a 3D sipe is shown by a two-dot chain line. As shown in FIG. 3, the maximum depth d1 of the 1 st sipe 23 is preferably greater than the maximum depth of the 1 st longitudinal groove 19. The depth d1 of the 1 st sipe 23 is 2.50 to 4.00 times the depth of the 1 st longitudinal groove 19. Such a 1 st sipe 23 can exhibit excellent water absorbency.

The 1 st sipe 23 of the present embodiment has a tie 25 having a raised bottom. The tie bars 25 include, for example, an end tie bar 26 provided at an end portion of the 1 st sipe 23 opposite to the 1 st longitudinal groove 19, and a center tie bar 27 provided at a central portion of the 1 st sipe 23 in the longitudinal direction. The central bead 27 is provided in a central region obtained by dividing the 1 st sipe 23 by 3 times in the longitudinal direction thereof, for example. In a more preferred embodiment, at least a part of the central tie bar 27 overlaps with the center position of the 1 st sipe 23 in the longitudinal direction. Such end lacing wires 26 and center lacing wires 27 can inhibit the 1 st sipe 23 from being excessively opened, thereby improving braking performance on ice.

The height h1 of the central rib 27 is, for example, less than the height of the end ribs 26. The height h1 of the central lacing wire 27 is 40-60% of the maximum depth d1 of the 1 st knife groove 23. In addition, the width W7 of the central tendon 27 is less than the width of the end tendons 26. The width W7 of the center tie 27 is, for example, 80% to 120% of the groove width W6 of the 1 st vertical sipe 19. Such a central lacing 27 can maintain the water absorbency of the 1 st sipe 23 and can suppress excessive opening of the 1 st sipe 23. The width W7 is measured at a height of 50% of the maximum height of the center tie 27, for example.

From the same viewpoint, it is preferable that the depth of the portion where the tie bar 25 is provided is larger than the depth of the 1 st vertical groove 19.

As shown in fig. 2, the outer intermediate land portion 12 is provided with a plurality of outer intermediate lateral grooves 29 extending in the tire axial direction. The outer intermediate lateral groove 29 intersects the outer intermediate land portion 12. Thereby, the outer intermediate land portion 12 is divided into a plurality of outer intermediate blocks 30.

The outer intermediate lateral groove 29 is inclined in, for example, the 1 st direction (lower right in the drawings of the present specification) with respect to the tire axial direction. The angle θ 2 of the outer intermediate lateral groove 29 with respect to the tire axial direction is, for example, 45 ° or less, preferably 15 to 25 °. Such an outer intermediate lateral groove 29 improves the braking performance on ice and the turning performance in a balanced manner.

Preferably, the end of the outer intermediate lateral groove 29 on the outer tread end To side overlaps a region extending parallel To the tire axial direction at the end of the outer shoulder lateral groove 18 on the inner tread end Ti side. As a result, during travel on snow, a hard snow column is generated at the intersection of the outer shoulder circumferential groove 5, the outer shoulder lateral groove 18, and the outer intermediate lateral groove 29, and a large reaction force is obtained by shearing the hard snow column. Therefore, on-snow performance is improved.

In the present embodiment, the outer crown circumferential grooves 6 extend in a zigzag shape including the long inclined portion 6a and the short inclined portion 6b having a smaller length than that, and at least 1 of the outer intermediate lateral grooves 29 communicates with the short inclined portion 6 b. In a more preferred embodiment, the outer intermediate lateral grooves 29 communicating with the short inclined portion 6b and the outer intermediate lateral grooves 29 communicating with the long inclined portion 6a are alternately provided in the tire circumferential direction. Such an outer intermediate lateral groove 29 can generate a hard snow column at the intersection with the short inclined portion 6 b.

The outer middle block 30 is provided with a middle interruption groove 32. The intermediate interruption groove 32 extends from the outboard crown circumferential groove 6 and is interrupted within the outboard intermediate block 30. The groove width W8 of the intermediate interruption groove 32 is smaller than the groove width of the outer shoulder lateral groove 18 and the groove width of the outer intermediate lateral groove 29. Such an intermediate cutout groove 32 can maintain the rigidity of the outer intermediate block 30 and can improve the braking performance on ice.

The intermediate interruption groove 32 is inclined in the 1 st direction with respect to the tire axial direction, for example. In a preferred embodiment, the angle difference between the intermediate interruption groove 32 and the outer intermediate lateral groove 29 is 5 ° or less. Such an intermediate cutout groove 32 helps suppress uneven wear of the outer middle block 30.

The outer intermediate block 30 is provided with a plurality of outer intermediate sipes 33. The outer intermediate sipe 33 is inclined, for example, in the 2 nd direction (in each drawing of the present specification, the upper right direction) opposite to the 1 st direction with respect to the tire axial direction. The outer intermediate sipe 33 has an angle of, for example, 15 to 25 ° with respect to the tire axial direction. In the case where the sipe extends in a zigzag shape, the inclination direction and angle thereof are measured on a virtual straight line connecting both ends of the sipe.

An enlarged view of the inboard shoulder land portion 13 is shown in fig. 4. As shown in fig. 4, the inner-shoulder land portion 13 is divided into a plurality of inner-shoulder blocks 35 by a plurality of inner-shoulder lateral grooves 34 extending in the tire axial direction.

The inner-shoulder lateral groove 34 is inclined in the 2 nd direction with respect to the tire axial direction, for example. In the present embodiment, the angle θ 3 of the inner shoulder lateral groove 34 with respect to the tire axial direction is larger than the angle of the outer shoulder lateral groove 18 with respect to the tire axial direction. Specifically, the angle θ 3 of the inner shoulder lateral groove 34 with respect to the tire axial direction is 5 to 15 °. Such an inner shoulder lateral groove 34 improves the braking performance on ice and the cornering performance in a balanced manner.

The maximum width W9 in the tire axial direction of the inner shoulder block 35 is, for example, 15% to 25% of the tread width TW. In a more preferred aspect, the maximum width W9 in the tire axial direction of the inner shoulder block 35 is smaller than the maximum width W2 in the tire axial direction of the outer shoulder block 20. This makes the steering feel linear during turning, thereby improving steering stability.

At least one of the inner shoulder blocks 35 is divided into a 3 rd block piece 41 on the inner tread end Ti side and a 4 th block piece 42 on the outer tread end To side by a 2 nd longitudinal groove 38 extending in the tire circumferential direction.

The 2 nd vertical groove 38 is disposed in, for example, a central region where the inner shoulder block 35 is divided by 3 times in the tire axial direction. The distance between the groove center line of the 2 nd vertical narrow groove 38 and the center position of the inner shoulder block 35 in the tire axial direction is 10% or less of the maximum width W9 of the inner shoulder block 35 in the tire axial direction. The 2 nd vertical sipe 38 extends linearly in parallel to the tire circumferential direction. Thus, the maximum width of the 4 th block 42 in the tire axial direction is 40% to 60% of the maximum width of the inner shoulder block 35 in the tire axial direction.

The 2 nd vertical fine groove 38 has a groove width W10 of more than 0.6 mm. The groove width W10 is, for example, 0.8 to 2.0mm, preferably 1.0 to 1.5 mm. The depth of the 2 nd vertical groove 38 is, for example, 1.5 to 3.0 mm. In a preferred embodiment, the depth of the 2 nd vertical groove 38 is greater than the depth of the 1 st vertical groove 19. Such a 2 nd longitudinal groove 38 contributes to the improvement of turning performance on ice.

The 3 rd block piece 41 is provided with a plurality of 3 rd sipes 43. The 4 th block piece 42 is provided with a plurality of 4 th sipes 44. In the present embodiment, the total number N4 of the 4 th sipes 44 arranged in the one 4 th block piece 42 is greater than the total number N3 of the 3 rd sipes 43 arranged in the one 3 rd block piece 41. This improves the braking performance on ice and the turning performance in a balanced manner.

In another embodiment, the total number N4 of the 4 th sipes 44 of the 4 th block piece 42 may be the same as the total number N3 of the 3 rd sipes 43 of the 3 rd block piece 41. In such an embodiment, uneven wear of the inner shoulder blocks 35 is suppressed, and the noise generated by the outer shoulder blocks 20 and the noise generated by the inner shoulder blocks 35 are dispersed in frequency band, thereby improving the noise performance.

The total number N3 of the 3 rd sipes 43 in the present embodiment is, for example, 3 to 5. The total number N4 of the 4 th sipes 44 is, for example, 4 to 6. However, the present invention is not limited to such an embodiment.

The tire axial direction component of the 3 rd sipe 43 and the 4 th sipe 44 is larger than the tire circumferential direction component. It is preferable that the 3 rd sipe 43 and the 4 th sipe 44 respectively cross each block piece in the tire axial direction. In a more preferred form, in the 3 rd block piece 41 and the 4 th block piece 42, sipes having a tire circumferential direction component larger than a tire axial direction component are not provided. Thereby, the traction performance and the braking performance on ice are further improved.

In addition, the structure of the 1 st sipe 23 described above can be applied to the 3 rd sipe 43 and the 4 th sipe 44.

An enlarged view of the inboard intermediate land portion 14 and the crown land portion 15 is shown in fig. 5. As shown in fig. 5, the inner intermediate land portion 14 is divided into a plurality of inner intermediate blocks 48 by a plurality of inner intermediate lateral grooves 46 extending in the tire axial direction.

The inner intermediate lateral groove 46 is inclined in the 1 st direction with respect to the tire axial direction, for example. The angle θ 4 of the inner intermediate lateral groove 46 with respect to the tire axial direction is, for example, 45 ° or less and is larger than the angle of the outer shoulder lateral groove 18 with respect to the tire axial direction. Specifically, the angle θ 4 of the inner intermediate lateral groove 46 is 25 to 35 °.

The inboard middle block 48 is provided with a flex groove 50. The bending groove 50 includes, for example, a 1 st groove portion 51 and a 2 nd groove portion 52 inclined in a 2 nd direction with respect to the tire axial direction, and a 3 rd groove portion 53 disposed therebetween and inclined in the 1 st direction with respect to the tire axial direction. The bent groove 50 is bent into an N-shape by these groove portions, and traverses the inner intermediate block 48. Such a bending groove 50 provides frictional force in various directions while traveling on ice and snow.

The 1 st groove portion 51 of the bending groove 50 communicates with the inner crown circumferential groove 7. The 2 nd groove portion 52 communicates with the inner shoulder circumferential groove 8. The groove width of the 2 nd groove portion 52 is smaller than the groove width of the 1 st groove portion 51. The groove width of the 3 rd groove portion 53 is smaller than the groove width of the 2 nd groove portion 52. Such a bending groove 50 suppresses uneven wear of the inner middle block 48 and improves on-ice performance.

The inboard middle block 48 is provided with a plurality of inboard middle sipes 54. The inside intermediate sipes 54 are inclined in the 2 nd direction with respect to the tire axial direction, for example. Such an inner intermediate sipe 54 interacts with other sipes to generate frictional force in a plurality of directions, thereby improving braking performance and cornering performance on ice in a balanced manner.

The structure of the 1 st sipe 23 described above can be applied to the inside intermediate sipe 54.

The crown land portion 15 includes a plurality of crown blocks 58 divided by a plurality of crown sipes 56 extending in the tire axial direction.

The crown transverse groove 56 is inclined in the 2 nd direction with respect to the tire axial direction, for example. The crown groove 56 has an angle θ 5 of 45 ° or less with respect to the tire axial direction and is larger than an angle θ 1 of the outer shoulder groove 18 with respect to the tire axial direction. The angle θ 5 of the crown transverse groove 56 is, for example, 15 to 25 °.

The crown block 58 is provided with, for example, a 1 st interrupted groove 61 and a 2 nd interrupted groove 62. The 1 st interrupting groove 61 extends from the outboard crown circumferential groove 6 and is interrupted within the crown block 58. The 2 nd interrupted groove 62 extends from the inboard crown circumferential groove 7 and is interrupted within the crown block 58. Such 1 st and 2 nd interrupted grooves 61 and 62 contribute to maintaining the rigidity of the crown block 58 and improving the on-ice performance and the on-snow performance.

The crown block 58 is provided with a plurality of crown sipes 60. The crown sipes 60 are inclined in the 1 st direction with respect to the tire axial direction, for example. The structure of the 1 st sipe 23 described above can be applied to the crown sipe 60.

Although the tire according to the embodiment of the present invention has been described in detail above, the present invention is not limited to the above-described specific embodiment, and can be implemented in various forms by being modified.

[ examples ] A method for producing a compound

Tires having a size 195/65R15 of the basic tread pattern of fig. 1 were produced in a trial based on the specifications of table 1. As a comparative example, a tire having the outer shoulder land portion a shown in fig. 6 was prototyped. As shown in fig. 6, in the tire of the comparative example, the total number N1 of the 1 st sipes c provided in the 1 st block piece b is the same as the total number N2 of the 2 nd sipes e provided in the 2 nd block piece d. The tire of the comparative example had a pattern substantially the same as the pattern shown in fig. 1, except for the above-described structure. For each test tire, braking performance on ice and cornering performance were tested. The general specifications and test methods of the respective test tires were as follows.

Mounting a rim: 15X 6.0JJ

Tire internal pressure: 230kPa for front wheel and 230kPa for rear wheel

Testing the vehicle: front wheel drive vehicle with displacement of 1500cc

Tire mounting position: all wheels

< braking Performance on Ice >

The test vehicle was driven on ice, and the braking performance on ice was evaluated by the sense of the driver. The result is a score of 100 in comparative example, and the larger the value, the more excellent the braking performance on ice.

< cornering behaviour on ice >

The test vehicle was driven on ice, and the turning performance on ice was evaluated by the sense of the driver. The results are shown by a score of 100 in comparative example, and the larger the value, the more excellent the cornering performance on ice.

The results of the tests are shown in table 1.

[ TABLE 1 ]

As shown in table 1, it was confirmed that the tires of the examples improve braking performance and cornering performance on ice.