| 摘要 |
PURPOSE:To aim at reducing noise without sacrificing the wear resistance of a pneumatic tire, by specifying the ratio between the length of maximum pitches and the length of minimum pitches in a tread pattern, and the angles of the main groove side block walls extending from the maximum pitch length part to the minimum pitch length start. CONSTITUTION:A plurality of annular main grooves 1 are formed in the tread surface of a tire in the circumferential direction EE', and a plurality of subgrooves 2 connecting between the main grooves 1 are disposed in the widthwise direction of the tire so that a plurality of blocks 3 are formed. In this tread pattern, the ratio alpha between a maximum pitch length (a) and a minimum pitch length (b) is set such as alpha>1.5. The angles of the main side block wall surfaces extending from the maximum pitch length part to the minimum pitch length part are set to be beta1, beta2,...betai, which are such that beta1>betai-1>betai-2>...beta2>beta1, betai<=20. With this arrangement, the pitch maximum and minimum ratio alpha may be made to be large, thereby it is possible to attain low noise without sacrificing the wear-resistance. |
