JPH09263111A - Pneumatic tire for running on ice and snow - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To suppress or prevent the occurrence of a sipe cracking failure or a block chunk-out failure in a pneumatic tire for traveling on ice and snowy roads in which a tread is provided with a large number of blocks with a large number of sipes formed. However, it is to provide a pneumatic tire for traveling on ice and snow roads, which has excellent steering stability on ice. SOLUTION: In a pneumatic tire for running on ice and snowy roads, which comprises a number of blocks on a tread, the blocks include:
A large number of composite sipes formed by intersecting two or more sipes extending in different directions are formed, and the composite sipes are independent composite sipes that are not connected to or intersect with other composite sipes. Pneumatic tire for driving.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic tire for traveling on ice and snow roads, which has a large number of blocks on a tread, and particularly to a pneumatic tire for traveling on ice and snow roads in which a large number of sipes are formed in these blocks. It is about.

[0002]

2. Description of the Related Art Conventionally, in a pneumatic tire for running on ice and snow roads, in which a tread is provided with a large number of blocks having a large number of sipes as described above, a tire between the road surface and the tire when running on the ice and snow road surface is used. Excluding the water film, it is effective to increase the number of sipes in the same block, in other words, to narrow the sipes and increase the sipes density in order to improve the steering stability performance on ice. Are known.

[0003]

However, when the sipe density is increased in a pneumatic tire for traveling on ice and snow roads having a large number of blocks with a large number of sipes formed on the tread as described above, the block rigidity decreases and the sipe is reduced. Cracking failures and block chunk out failures are more likely to occur.

The object of the present invention is to eliminate the above-mentioned drawbacks of the prior art, and to provide a pneumatic tire for traveling on ice and snowy roads, in which a large number of blocks having a large number of sipes are provided on a tread, and a sipe crack failure or a block occurs. It is to provide a pneumatic tire for traveling on ice / snow road surface which is excellent in steering stability on ice while suppressing or preventing occurrence of chunk out failure.

[0005]

In order to achieve the above object, the pneumatic tire of the present invention is a pneumatic tire for traveling on ice and snow roads, which comprises a large number of blocks on a tread,
(1) A large number of composite sipes formed by intersecting two or more sipes extending in mutually different directions are formed in the block, and (2) the composite sipes are not connected to or intersect with other composite sipes, independent. A pneumatic tire for traveling on ice and snow roads, which is a composite sipe. In order to achieve the above object, the pneumatic tire of the present invention is a cross-shaped composite sipe, wherein the composite sipe is composed of a sipe extending in the tire circumferential direction and a sipe extending in the tire rotation axis direction. preferable. To achieve the above object, in the pneumatic tire of the present invention, the composite sipe is composed of a sipe extending in an upward right direction with respect to the circumferential direction and a sipe extending in an upward left direction with respect to the circumferential direction. It is preferably an X-shaped composite sipe. In order to achieve the above object, in the pneumatic tire of the present invention, the composite sipe includes one sipe extending in a certain direction and a plurality of other sipe extending intersecting in different directions. It is preferably a multi-intersection type composite sipe. In order to achieve the above-mentioned object, the pneumatic tire of the present invention has two or more different composite sipes, such as the cross-shaped composite sipes, the X-shaped composite sipes composite sipes, or the multi-intersection composite sipes, in the block. It is preferable that many are formed.
In order to achieve the above object, in the pneumatic tire of the present invention, the block includes a plurality of rows in which composite sipes of the same or substantially the same size are arranged at equal intervals in the circumferential direction, and the composite rows are provided between adjacent rows. The sipes are preferably arranged with a shift of 1/3 to 2/3 pitch, and more preferably with a pitch of 1/2.

In conventional tires, if the number of sipes in the same block is increased in order to improve the steering stability on ice, the rigidity of the block is reduced and a sipe cracking failure or a block chunk out failure is likely to occur. In some cases, the durability performance of the block was reduced. In contrast,
The pneumatic tire of the present invention has the above-mentioned configuration,
A large number of composite sipes formed by intersecting two or more sipes extending in different directions are formed in the block. Since these composite sipes are independent composite sipes that are not connected or intersected with other composite sipes, they are on ice. Even if the number of sipes is increased, that is, the sipes are narrowed to increase the sipes density in order to improve the steering stability, the entire block is less likely to be deformed. As a result, the occurrence of sipe cracking failures and block chunk out failures is suppressed or prevented. In the present specification, the term “block” means a block in a broad sense including ribs and lugs in addition to a block in a narrow sense.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Pneumatic tires of Examples 1 to 6 according to the present invention and conventional pneumatic tires will be described below with reference to the drawings. In each of FIGS. 1 to 7, one representative block of a large number of blocks included in a tread of a proto type pneumatic tire for passenger cars traveling on ice and snow roads is shown.

[0008]

1 is a block 1 provided in a tread of a tire according to a first embodiment of the present invention, in which the block 1 has two sipes 21, 22 extending in mutually different directions.
A large number of composite sipe 2 formed by intersecting with each other is formed, and this composite sipe 2 is an independent composite sipe that is not connected to or intersects with another composite sipe 2. This composite sipe 2 is composed of a sipe 21 extending in the tire circumferential direction and a sipe 22 extending in the tire rotation axis direction.
It is. The block 1 is provided with five rows of composite sipes 2 of the same size arranged at equal intervals in the circumferential direction at a pitch p, and the composite sipes 2 are arranged with a shift of about 1/3 pitch between adjacent rows. . That is, assuming that the pitch shift amount between adjacent columns is d, the composite sipe 2 is arranged between adjacent columns in a relationship of d 1 / 3p.

FIG. 2 shows a block 1 provided on a tread of a tire according to a second embodiment of the present invention, which is a composite sipe 3
However, the sipe 31 that extends to the right with respect to the circumferential direction
And the sipe 32 extending in the leftward upward direction with respect to the circumferential direction, which is the X-shaped composite sipe 3.

FIG. 3 shows a block 1 provided in a tread of a tire according to a third embodiment of the present invention. In this block 1, a cross type composite sipe 2 similar to the first embodiment and a second embodiment are provided.
The same X-shaped composite sipe 3 is formed in a mixed manner.

FIG. 4 shows a block 1 provided on a tread of a tire according to a fourth embodiment of the present invention, which is a composite sipe 4
Is a multiple cross-type composite sipe 4, which is composed of one sipe 41 extending in the circumferential direction and two sipe 42, 43 extending in an upward left direction with respect to the circumferential direction.

FIG. 5 shows a block 1 provided on a tread of a tire according to a fifth embodiment of the present invention, and this block 1 has a plurality of cross-type composite sipes 5 and 6 of different types.
And are formed in a mixed manner.

FIG. 6 shows a block 1 provided on a tread of a tire according to a sixth embodiment of the present invention, and this block 1 has a plurality of cross-type composite sipes 7 and 8 of different types.
And are formed in a mixed manner.

FIG. 7 shows a block 1 provided on a tread of a tire of a comparative example, and five sipes 9 extending in the circumferential direction are formed on the block 1. The tire of the conventional example is the same as the tire of the comparative example, except that the block 1 is formed with four sipes extending in the circumferential direction.

Next, in order to compare and evaluate the tire of Example 1, the tire of Comparative Example, and the tire of Conventional Example, evaluation tests of steering stability on ice and block durability were carried out.

As a result of the above-mentioned evaluation test, regarding the steering stability on ice, assuming that the tire of the conventional example is 100, the tire of the comparative example and the tire of the example 1 are both 12
It was 0. In terms of block durability, the tire of the comparative example is 80 when the tire of the conventional example is 100.
The tire of Example 1 was 105.

[0017]

From the above results, compared to the conventional tire,
It can be seen that the tire of the present invention is a tire having excellent steering stability on ice and block durability.

[Brief description of drawings]

FIG. 1 is a front view of a block provided on a tread of a tire according to the present invention.

FIG. 2 is a front view of a block provided on a tread of a tire according to the present invention.

FIG. 3 is a front view of a block provided on a tread of a tire according to the present invention.

FIG. 4 is a front view of a block provided on a tread of a tire according to the present invention.

FIG. 5 is a front view of a block provided on a tread of a tire according to the present invention.

FIG. 6 is a front view of a block included in the tread of the tire according to the present invention.

FIG. 7 is a front view of a block provided on a tread of a tire of a comparative example.

[Explanation of symbols]

 1 block 2 Cruciform compound sipes 3 X-shaped compound sipes 4 Multiple crossing compound sipes 5 Multiple crossing compound sipes 6 Multiple crossing compound sipes 7 Multiple crossing compound sipes 8 Multiple crossing compound sipes 9 Sipe extending in the circumferential direction p Pitch d Pitch deviation

Claims (7)

[Claims] 1. A pneumatic tire for traveling on ice and snowy roads, comprising a large number of blocks on a tread, wherein (1) a large number of composite sipes formed by intersecting two or more sipes extending in mutually different directions are formed in the blocks. (2) The pneumatic tire for traveling on ice and snow roads, wherein the composite sipe is an independent composite sipe that is not connected or intersected with other composite sipe. 2. The ice-snow road surface traveling according to claim 1, wherein the composite sipe is a cross-shaped composite sipe composed of a sipe extending in the tire circumferential direction and a sipe extending in the tire rotation axis direction. For pneumatic tires. 3. The composite sipe is an X-shaped composite sipe, which is composed of a sipe extending to the right in the circumferential direction and a sipe extending to the left in the circumferential direction. The pneumatic tire for traveling on ice and snow roads according to claim 1. 4. The composite sipe is a multi-intersection composite sipe composed of one sipe extending in a certain direction and a plurality of other sipe extending intersecting in different directions. The pneumatic tire for traveling on ice and snow roads according to claim 1. 5. The block includes the cross-shaped composite sipe,
The pneumatic tire for traveling on ice and snowy roads according to claim 1, wherein two or more different composite sipes of the X-shaped composite sipes or plural crossing composite sipes are formed in large numbers. 6. The block comprises a plurality of rows in which composite sipes of the same or substantially the same size are arranged at equal intervals in the circumferential direction, and the composite sipes are displaced by 1/3 to 2/3 pitch between adjacent rows. The pneumatic tire for traveling on ice and snow roads according to any one of claims 1 to 5, wherein 7. The block is provided with a plurality of rows in which composite sipes of the same or substantially the same size are arranged at equal intervals in the circumferential direction, and the composite sipes are arranged with a 1/2 pitch shift between adjacent rows. The pneumatic tire for traveling on ice and snowy roads according to claim 6, wherein