| 摘要 |
PROBLEM TO BE SOLVED: To reduce noise, maintaining drainability and durability, by providing oblong holes extending in the surface direction from a tire tread inner surface on only a groove side wall surface of a main groove extending in a tire circumferential direction in a tire tread part. SOLUTION: In a tire tread part 1, a main groove 2 extends in a tire peripheral direction and a rib 3 is constituted of main grooves 2, 2 adjacent to the rib 3. Oblong holes 11 are the rectangular ones extending in the surface direction of a tire tread formed on a groove side wall surface 2a of the main groove 2. A large number of these oblong holes 4 are formed along the tire circumferential direction but the oblong holes 4 are not formed on a groove bottom wall surface 2b of the main groove 2. Therefore, because air channel cross-sectional area within the main groove 2 at the time of ground remarkably fluctuates during the rolling of the tire, the fluctuation causes sufficient energy loss for air flow. As a result, columnar resonance sound generated is reduced and drainability and tire water resistance are also excellently possessed. |
