| 摘要 |
PURPOSE:To improve the performance of draining by providing ridgelike folds that extend obliquely toward a groove bottom from a stepping on end edge side in inclination opposite to the direction of the opposite inclination of each sub groove, at the groove wall surface of each sub groove limited by means of a stepping on end edge, at each of tread land portion divisions. CONSTITUTION:Each sub groove 3 opens to a tread 1 and extends in retreat and inclination toward both side edges of the tread 1 from a center sphere, and both ends opens to the respective side edges of the tread, 1 and between them, the sub groove 3 crosses with main grooves 2 that run along the circumference of the tread 1, and tread land portions 4 of a herringbone pattern are formed with main grooves 2 and sub grooves 3. Ridgelike folds 4b that extend obliquely toward a groove bottom from a stepping on end edge side in inclination opposite to the direction of the retreat slope of a sub groove 3, are provided at the groove wall surface 3a of the sub groove 3 limited by means of the grounding edge 4a of a tread land portion 4. As a result, when invasion into a ground contact sphere is made in a reverse direction to herringbone pattern divergence by means of tire rotation, a water film on a road surface is scraped off by means of stepping on end 4a, and scattering is conducted to the side ends of the tread or adjoining main grooves 2 along ridgelike folds 4b. |
