Patent ID: 7637295
Filing Date: 2009-12-29
Classification: B60C,Y10S

Abstract:
1. A pneumatic tire where a plurality of longitudinal grooves extending in a tire circumferential direction and a plurality of lateral grooves extending in a tire widthwise direction are provided in a tread portion, a plurality of blocks are defined by these longitudinal and lateral grooves, and a plurality of sipes extending in the tire widthwise direction are provided to each of the blocks, wherein, with regard to each of the sipes, a zigzag shape with an amplitude in the tire circumferential direction is formed on a tread surface, bent portions ranging in the tire widthwise direction while bent in the tire circumferential direction are formed inside the block at at least two positions in the tire radial direction, and a zigzag shape with an amplitude in the tire radial direction is formed in each of the bent portions, and wherein, while the amplitude of the sipe in the tire circumferential direction is set constant, a tilt angle of the sipe in the tire circumferential direction to a normal-line direction of the tread surface is set smaller at a portion closer to the bottom of the sipe than that in a portion closer to the tread surface, and the amplitude of the bent portions in the tire radial direction is set larger at a portion closer to the bottom of the sipe than that in a portion closer to the tread surface.