JP4149048B2 - Pneumatic tire with sipe on tread - Google Patents

Description

【００１２】
【発明の効果】
上記の評価結果から、本発明に基づく実施例の空気入りタイヤは従来例の空気入りタイヤと比べて、摩耗中期（５０％摩耗）での乾燥した路面上および濡れた路面上を走行したときのタイヤの操縦安定性能の格差が小さくなっていることが分かる。
【図面の簡単な説明】
【図１】本発明によるサイプの断面図である。
【図２】従来のサイプの断面図である。
【符号の説明】
Ｔ トレッド
Ｓ サイプ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire having a tread with sipes.
[0002]
[Prior art]
In order to ensure the road surface grip performance of the tire when traveling on a wet road surface, F. Mr. Sipe invented a narrow cut or knife cut in the tread and was granted a US patent in 1922, but this technique is now widely used in the tire industry and is named after the inventor's name. It is called sipe or siping.
[0003]
[Problems to be solved by the invention]
By providing the tread with a narrow cut, that is, a sipe, the road surface grip performance of the tire when traveling on a wet road surface is improved, and the steering stability performance is improved. However, as the tread wears as the tire travels, the steering stability performance of the tire on a wet road surface gradually decreases.
On the other hand, the steering stability performance of a tire when driving on a dry road surface once improved from the initial wear to the middle wear as the tread wears as the tire travels, and then the road surface dried toward the end of wear. The steering stability performance of the tire on the above gradually decreases.
As described above, in the pneumatic tire equipped with the conventional sipe in the tread, the change in the steering stability performance from the initial wear to the middle wear tends to conflict between the wet road surface and the dry road surface. There was a drawback that the difference in steering stability performance in the middle period of wear widened between the road surface and the dry road surface.
[0004]
An object of the present invention is to provide a pneumatic tire that eliminates the problems of the prior art as described above and reduces the difference in steering stability performance on wet and dry road surfaces in the middle stage of wear. It is.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, a pneumatic tire according to the present invention is a pneumatic tire provided with a sipe on a tread. (1) The sipe is located most adjacent to an outer region located adjacent to the tread surface and from the tread surface. an inner region located apart is formed in an intermediate region located between the outer region and the inner region, (2) the sipe thickness is the most thick have uniform thickness throughout the intermediate region as it is a pneumatic tire, wherein thinnest and such by Rukoto in the interior region.
[0006]
Conventionally, the sipe thickness is uniform from the tread surface to the innermost sipe bottom of the tread. For this reason, there is a tendency that the difference in steering stability performance between the wet road surface and the dry road surface in the middle stage of wear is widened. The pneumatic tire of the present invention has the above-described configuration. In particular, (1) the sipe has an outer region located adjacent to the tread surface, an inner region located on the innermost side of the tread, and the outer region. and it is formed in an intermediate region located between the inner region, (2) the sipes has a thickness of most have a thickness throughout of the intermediate region becomes a uniform thickness, and thinnest at the inner region that Do not. As a result, the sipe thickness increases from the early wear stage to the middle wear stage, resulting in a decrease in block rigidity. The degree to which the road surface grip performance of the tire decreases when traveling on a wet road surface as it wears is suppressed. In this way, problems due to the difference in steering stability performance on wet and dry road surfaces in the middle of wear are eliminated.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, tires of examples and conventional tires according to the present invention will be described with reference to the drawings.
[0008]
FIG. 1 is a cross-sectional view of a sipe S provided on a tread T of a tire according to an embodiment of the present invention. As shown, the sipe S includes an outer region S1 positioned adjacent to the tread surface, an inner region S3 positioned farthest from the tread surface, and an intermediate region S2 positioned between the outer region S1 and the inner region S3. is formed by the thickness of the sipe S is the most have a thickness over the entire intermediate region S2, it becomes a uniform thickness, ing and thinnest inner region S3.
[0009]
FIG. 2 is a cross-sectional view of a sipe S provided on a tread T of a conventional tire. The sipe thickness of the conventional example is uniform from the tread surface to the sipe bottom as shown in the figure.
[0010]
For the pneumatic tire of the example according to the present invention and the pneumatic tire of the conventional example, a comparative test of the steering stability performance of the tire when traveling on a dry road surface and a wet road surface was performed.
In the comparative test results,
About the steering stability performance of the tire when traveling on a dry road surface, when the steering stability performance at the initial stage of wear (0% wear) of the pneumatic tire provided with the sipe of the above-mentioned conventional example is displayed as an index, The steering stability performance at the middle stage of wear (50% wear) is 120, and the steering stability performance at the end stage of wear (75% wear) is 90. The steering stability performance at 98% wear is 98, the steering stability performance at the middle stage of wear (50% wear) is 100, and the steering stability performance at the end stage of wear (75% wear) is 90.
The steering stability performance of the tire when traveling on a wet road surface is expressed as an index with the steering stability performance at the initial wear (0% wear) of the pneumatic tire equipped with the sipe of the above-described conventional example as 100. The steering stability performance in the middle stage of wear (50% wear) is 65, and the steering stability performance in the last stage of wear (75% wear) is 55. The steering stability performance at 104% wear was 104, the steering stability performance was 78 at the middle wear stage (50% wear), and the steering stability performance was 55 at the end wear stage (75% wear).
Table 1 summarizes the results of the comparative test.
[0011]
[Table 1]

[0012]
【The invention's effect】
From the above evaluation results, the pneumatic tires of the examples according to the present invention were compared with the conventional pneumatic tires when they drove on the dry road surface and the wet road surface in the middle period of wear (50% wear). It can be seen that the disparity in the steering stability performance of the tire has been reduced.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a sipe according to the present invention.
FIG. 2 is a cross-sectional view of a conventional sipe.
[Explanation of symbols]
T tread S sipe

Claims (1)

In the pneumatic tire provided with a sipe in the tread, (1) the sipe includes an outer region located adjacent to the tread surface, an inner region located farthest from the tread surface, the outer region, and the inner region. is formed in an intermediate region located between, (2) the sipes has a thickness of most have a thickness throughout of the intermediate region becomes a uniform thickness, characterized thinnest and such by Rukoto in the interior region And pneumatic tires.

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