| 摘要 |
PROBLEM TO BE SOLVED: To significantly improve bead durability while restraining weight increase low. SOLUTION: A bead part 4 is provided with a bead reinforcing layer 10 of a steel chord having an inside part 10a and an outside part 10b raised along a ply body part 6a and a folded part 6b of a carcass 6, and a bead apex rubber 8. The thickness ta of the bead apex rubber 8 at a point P separated from a flange Rf is 1.15-1.25 times a core width Wz of a bead core 5, and the thickness tb at an outer end F of the ply folded part 6b is 0.8-0.9 times the thickness ta. The height Hp of the bead reinforcing layer 10 at the inside part 10a is 1.0-1.12 times the height Hn of the ply folded part 6b, and the thickness T of rubber from an outer end Ea of the inside part 10a to a tire inner lumina face is 0.3-0.45 times the apex thickness ta. COPYRIGHT: (C)2004,JPO&NCIPI
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