| 摘要 |
The pneumatic tire includes a carcass layer (4) being laid between paired right and left bead sections, and at least two belt layers being arranged at an outer peripheral side of the carcass layer in a tread section. The pneumatic tire is characterized in that a hybrid cord, used as reinforcement cords of the carcass layer, is obtained by imparting second twists, in a reverse direction of the first twists, to a bundle of: at least one rayon first twist yarn being obtained by imparting first twists to a bundle of rayon fibers; and at least one aramid first twist yarn being obtained by imparting, to a bundle of aramid fibers, first twists in the same direction of the first twists of the rayon first twist yarn. The total fineness of the hybrid cord is in a range of 3500 dtex to 9000 dtex, the second twist coefficient K of the hybrid cord expressed by Equation 1 is in a range of 1700 to 2400, 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,
K=Tˆš(Tr/Ár+Ta/Áa) ... (Equation 1)
where T denotes the number of second twists of the hybrid cord (times/10 cm), Tr denotes the total fineness of the rayon fibers (unit: dtex), Ár denotes the specific gravity of the rayon fibers, Ta denotes the total fineness of the aramid fibers (unit: dtex), and Áa denotes the specific gravity of the aramid fibers. |
