| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire which is lighter in weight and exhibits increased flat-spot resistance while keeping its durability and driving stability. <P>SOLUTION: In the pneumatic tire wherein at least two belt layers 8 are arranged in a tread section 1, a hybrid cord obtained by imparting second twists, in a reverse direction of the first twists, to a bundle of first rayon twist yarn and first aramid twist yarn is used as reinforcement cords of a carcass layer 4, the total fineness of the hybrid cord is in a range of 3,500 dtex to 9,000 dtex, the second twist coefficient K of the hybrid cord expressed by Equation (1) below is in a range of 1,700 to 2,400, the tensile strength of the hybrid cord is not less than 5.5 cN/dtex when absolutely dry, and the elongation percentage of the hybrid cord under a load of 1.8 cN/dtex is 2% to 4% when absolutely dry. Equation (1): K=T√(Tr/ρr+Ta/ρa) where T: the number of second twists of the hybrid cord (times/10 cm), Tr: the total fineness of the rayon fibers (dtex), ρr: the specific gravity of the rayon fibers, Ta: the total fineness of the aramid fibers (dtex), and ρa: the specific gravity of the aramid fibers. <P>COPYRIGHT: (C)2009,JPO&INPIT |
