| 摘要 |
PURPOSE:To improve durability by wrapping a prescribed number of inner layers made of thick cords of the prescribed fiber degree from inside to outside in bead wires, by arranging one outer layer made of thinner cords than this in a wrapping part, and by setting the total number of carcass layers at odd number. CONSTITUTION:Thick cords more than 3000d of fiber degree are used for a carcass inner layer 1 by two layers or four layers, and bead wires 3 are arranged by wrapping them from inside to outside. For example, they are constituted by plies 1a and 1b. And a carcass outer layer 2 is so arranged that one layer 2 using cords thinner than the cords of the inner layer 1, for example, nylon cords of 1860d cover wrapping parts 1a' and 1b' of the inner layers 1a and 1b. And the number of layers of all the carcass layers is set at odd number of 8 layers of 5 layers (in this embodiment, 3 layers). Durability can be improved by this constitution.
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