| 摘要 |
PURPOSE:To reduce the extent of damage to a crown part, by constituting a tire in setting up the base rubber specified in a loss factor and a modulus of complex elasticity in a space between turnover ends of a hold ply, in case of the radial-ply tire using a belt layer of the hold ply. CONSTITUTION:A belt layer 4 is made up of setting up a hold ply 4a, whose both sides are turned over to the upper side, and a one-layer cut end ply 4b at the inside. In addition, base rubber 6 of below 0.2 in a loss factor and above 70kg/cm<2> in a modulus of complex elasticity is set up in the part sandwiched by a turnover part 4T of the hold ply. In this case, turnover width TW of the turnover part 4T is set to a range of about 18-35% of width BW of the belt layer 4. And, the loss factor of cap rubber is set to more than 0.3 and its modulus of complex elasticity is set to a range of 50-90kg/cm<2>. With this constitution, rigidity in a tread central part is maintained and what is more, its damage is reducible. |
