| 摘要 |
<p>PURPOSE:To prevent the occurrence of cracks on a tread and the reduction of abrasion resistance by forming many hidden sipes exposed as a result of the abrasion of rubber in the tread rubber, and increasing the sipe density for a unit area toward the tread back face. CONSTITUTION:Multiple vertical grooves 3 are formed on the surface of a tread rubber 2 arranged so as to surround the outer periphery of the crown section of a carcass 1, and lug grooves 4 are continuously formed in the lateral direction to vertical grooves 3. Ribs 5 are formed between adjacent vertical grooves 3, and blocks 6 are formed between vertical grooves 3 and lug grooves 4. Many spaces, i.e., hidden sipes 7, exposed as a result of the abrasion of rubber by the running use are arranged in the tread rubber 2. Hidden sipes 7 are formed at different depths, and the sipe density on the plane parallel with the tread surface is increased toward the tread back face within the range to the abrasion limit when a tire is replaced.</p> |
