| 摘要 |
PURPOSE:To facilitate the stone taking in and throwing out of a plurality of grooves provided circumferentially on the peripheral surface of a tread part of the tire by effecting an appropriate improvement to the construction of the tread grooves. CONSTITUTION:The tread part is formed on the peripheral surface with two kinds of grooves 1 and 2 both running in zigzag fashion in the circumferential direction. The circumferential groove 1 has a width W1 of 2-8% of the lateral width of the tread part at both of the opening and bottom of the groove 1. On the bottom of the groove 1 are planted a number of projections 5... with a space therebetween in the circumferential direction and between the sidewall of the groove for avoiding the stone taking therein. The width of the groove 1 gradually decreases from the opening toward the bottom to an intermediate point and then gradually increases to the bottom. The height H2 of the projection from the groove bottom is set 20- 60%, preferably, 30-50% of the depth H of the groove, whereas the minimum width position H1 of the groove is set on the sidewall of a depth of 20-50% of the entire groove depth H. |
