| 摘要 |
PURPOSE:To prevent exfoliation of rubber from the ends part of a heavy-duty vehicle radial tyre provided with a composite tread, by constituting the cap and base rubbers of the radial tyre for satisfying specified conditions so that heat generation is restrained without sacrificing abrasion resistance, cut resistance, etc. CONSTITUTION:A radial tyre 1 comprises an reinforce ply having cords laid at substantially 90 deg. with respect to the equator plane of the tyre, a toroidal carcass play layer 3 having both ends locked to bead wires 2, a belt layer 4 having steel cords for reinforcing the crown part of the carcass ply 3, a tread rubber layer and a pair of left and right lateral wall parts 6. In this arrangement, the tread rubber layer 5 is composed of a composite structure of a cap rubber 7 laid at the ground gripping surface side of the tread rubber layer 5 and a base rubber 8 positioned adjacent to the upper part of the belt layer with both rubbers satisfying specified conditions as stated in a separate paragraph. The base rubber 8 particularly restrains heat generation due to the deformation of the ends of the radial tyre and disperses stress exerted thereto. Thus, it is necessary to completely cover the ends of the belt layer with the base rubber. |
