| 摘要 |
PURPOSE:To decrease noises by making variably pitch numbers of blocks of shoulder parts to be smaller than that of center parts in tires in which blocks are formed with main grooves and sub grooves. CONSTITUTION:Many ribs a-c are formed with main grooves 2 and many blocks 4a-4c are formed by a crossing of sub grooves 3 to each rib a-c. And in this case, pitches of blocks 4a-4c formed at each rib a-c are changed variably, and blocks are arranged independently for each rib a-c well as blocks having a different pitch for each rib a-c are arranged at random. Also, pitch numbers N for each rib are decreased gradually so that center part ribs a are the largest and shoulder part ribs c are the smallest. This constitution enables low noises. |
