| 摘要 |
PURPOSE:To prevent and restrain cracks from occurring in lateral groove bottom parts, and also prevent uneven wear on a block and a lug tread surface by providing inclining surfaces which incline so that grooves may be deeper than a road surface as the road surface comes nearer to the lateral grooves, on the edge parts of the blocks and lugs which are put between lateral grooves provided in both shoulder parts of a tread. CONSTITUTION:A number of deep lateral grooves 3 are provided on the part ranging from a tread 1 to shoulder ground contacting end of shoulder parts 1a, 1a on both ends and five longitudinal grooves 4 are provided in the central part of the tread 1, and the lateral grooves 3 which continues between the longitudinal grooves 4 in zig-zag form are provided to form the tread pattern of a block pattern. In this case, inclining surfaces 2 which decline toward the lateral grooves 3 side are formed on the edge parts of both shoulder parts facing the adjacent lateral grooves 3 of respective shoulder blocks 7 or lugs 9 so that the depth of the groove from a tread surface 11 may be larger as width (b) is smaller, that is the position is nearer to the lateral grooves 3 in a range of 4-20% of a distance of centers LP of adjacent horizontal grooves 3 so as to set depth h1 at the adjacent part to the lateral grooves 3 in a range of 10-30% of depth H of the lateral grooves 3. |
