| 摘要 |
PROBLEM TO BE SOLVED: To improve durability of a carcass layer in a pneumatic radial tire having the carcass layer with the usage of a 1+18 structured steal cord. SOLUTION: In this pneumatic radial tire, the steel cord 8 of the carcass layer 4 is the 1+18 structure constituted by a core wire (x) arranged in the center, six first sheath wires (a) arranged on an outer peripheral side thereof, six second sheath wires (b) arranged on an outer peripheral side thereof, and six third sheath wires (c) arranged between the second sheath wires (b). The relationship between a wire diameter d<SB>x</SB>of the core wire (x) and wire diameters d<SB>a</SB>, d<SB>b</SB>and d<SB>c</SB>of the first to third sheath wires (a), (b) and (c) is expressed as follows: d<SB>x</SB>≥d<SB>a</SB>≥d<SB>b</SB>>d<SB>c</SB>. The wire diameters d<SB>x</SB>, d<SB>a</SB>, d<SB>b</SB>and d<SB>c</SB>are three different diameters in a range of 0.15 to 0.25 mm. COPYRIGHT: (C)2004,JPO
|
