JPH09109616A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pattern by which partial abrasion resistance of a flat parts extending from a wide peripheral groove of a tire tread to the ground contact end in the width direction is improved. SOLUTION: A plurality of peripheral grooves 3 and flat parts A, B deviated by the peripheral grooves are arranged on a cylindrical tread, and a groove having the width narrower than the peripheral grooves is arranged on the flat part B of the flat parts, adjacent to the inner side of the peripheral groove 3 positioned in the outermost side in the tire width direction along the peripheral grooves.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a tread pattern for suppressing uneven wear of a tread in a pneumatic tire.

[0002]

2. Description of the Related Art Pneumatic tires often have a pattern having a plurality of large grooves in the tread portion in the circumferential direction in order to satisfy required performance such as drainage. For this reason, FIG.
As shown in Fig. 2, there is a grounding area from the thick groove 3 to the grounding end 1 on the outer side in the width direction, that is, the land portion A. However, this portion has a complicated behavior when the tread touches down, and the input is strict. It is empirically known that uneven wear is likely to occur.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a pattern for improving the uneven wear resistance of the land portion A in the portion extending from the thick circumferential groove 3 to the widthwise ground contact end 1.

[0004]

As shown in FIG. 1, in a land portion B adjacent to the inner side of a circumferential groove 3 located on the outermost side in the tire width direction, a narrower groove 5 is provided than a circumferential groove 3 to the circumferential groove 3. Place along. At this time, the narrow groove 5 preferably has a depth of at least 80% of the peripheral groove 3. In addition, land part B-1
It is preferable that the width in the tire axial direction is 3 mm or more and the width in the tire axial direction of the land portion B-1 is smaller than the width of the land portion B-2. In addition, the width of the narrow groove in the tire axial direction is appropriately half or less of the circumferential groove 3 to the so-called sipe width.

[0002]

[Operation] The deformation of the tread in the tread near the ground contact end and other parts is observed in detail. In FIG. 3, how the normal line drawn from the tread surface toward the belt during no load rolling changes with the load α by using the angle α, and the tread surface near the ground contact end and other parts The inner tread deformations were compared. As a result, it was found that the angle α of the tread near the ground contact end was larger than that of other parts especially at the time of kicking, and the amount of deformation was large, and the amount of this deformation was uneven wear (particularly in the case of rib pattern). Was found to cause uneven wear on shoulders and heel and toe wear in the case of block patterns.

Therefore, uneven wear (particularly, wear) is caused by bringing the tread land portion near the ground contact end where shoulder drop wear is likely to occur and the angle α at the time of kicking out of the tread land portions adjacent to each other with a circumferential groove in between. Attempt to improve shoulder wear). There are two ways of improving the above method: a method of reducing the angle α at the time of kicking out near the ground contact end and a method of increasing the angle α of the tread land adjacent to the tread land near the ground contact end at the time of kicking out. However, we decided to improve it by the latter method.

Then, as a method of increasing the angle α when the adjacent tread land portions are kicked out, a groove narrower than the circumferential groove is arranged in the circumferential direction in the adjacent tread land portions. In this way, the angle gradient when kicking the tread land portion from the vicinity of the ground contact end to the center of the tire was made gentle.

[0005]

EXAMPLE An example of a 215 / 60ZR15 tire will be described in detail with reference to FIG. in this case,
There are 4 circumferential thick grooves 3, and the tread surface is 5
It is divided into two land areas. Further, except for the land portion C, it is divided by the groove 6 in the width direction and has a block-shaped pattern. Further, the land portion B has two
It is divided into two parts, land part B-1 and land part B-2.
The width of the narrow groove 5 is 0.7 mm, and the width of the land portion B-1 is 11.0 mm.

[0006]

According to the present invention, the wide groove to the ground contact end 1 in the width direction
It is possible to greatly improve the uneven wear resistance of the land portion A up to. Compared with conventional tires, tires having these characteristics are different in heel and toe uneven wear due to the difference in wear amount between the leading end and the trailing end, and as shown in FIG. 5, about 24.0% in an indoor test. The improvement effect of was able to be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic view of a part of a tread according to the present invention.

FIG. 2 is a partially enlarged view of a tread portion according to another embodiment of the present invention.

FIG. 3 is an explanatory diagram of analysis of uneven wear.

FIG. 4 is a conceptual diagram of a part of a tread according to a conventional example.

FIG. 5 is a graph showing the effect of the present invention and showing the difference in the amount of wear between the stepped-in end and the kicked-out end of the block of the tire of the present invention and the tire of the conventional example.

[Explanation of symbols]

 1 tire tread ground contact edge 3 tread circumferential wide groove 5 circumferential narrow groove that divides land area 6 tread widthwise groove A landing edge side land portion of block pattern B via ground edge land portion and thick groove Land area

Claims (3)

[Claims] 1. A cylindrical tread is provided with a plurality of circumferential grooves and a land portion divided by the circumferential grooves, and is adjacent to the inner side of the circumferential groove located on the outermost side in the tire width direction of the land portions. A pneumatic tire characterized by arranging a groove having a width narrower than that of the circumferential groove in the land portion. 2. The pneumatic tire according to claim 1, wherein the narrow groove has a depth of at least 80% of an adjacent circumferential groove. 3. The tire axial distance between the circumferential groove and the narrow groove is 3 mm or more, and the axial inner land width of the circumferential groove is 5 mm.
It is 0% or less, The pneumatic tire of Claim 1 or Claim 2.