| 摘要 |
<p>PROBLEM TO BE SOLVED: To ensure high braking driving performance even at the beginning of wear with a mold release agent adhering as a thin film or even though block width becomes narrow by forming hole parts in the surface of blocks, and making the diameter of an outer hole part facing the surface of the block, larger than the diameter of an inner hole part on the inside. SOLUTION: A tread face 1 is provided with main grooves 2 extended along a circumferential direction T, and lateral grooves 3 extended in a cross direction, and a large number of blocks 4 are partitioned by the main grooves 2 and lateral grooves 3. A plurality of hole parts 5 are formed in the surface of each block 4. Each hole part 5 is composed of a plurality of hole parts with different diameters in the depth direction. An outer hole part on the surface is formed in inverted trunchated cone shape, and an inner hole part continuous with the outer hole part is formed in cylindrical shape. A diameter facing the surface of the outer hole part is larger than the diameter of the inner hole part. Even in the adhering state of a thin film of a mold release agent in the beginning of wear at the time of being new or even if block width becomes narrow, high braking driving performance can be ensured.</p> |
