| 摘要 |
PROBLEM TO BE SOLVED: To improve durability by relaxing stress concentration on the radial outer end edge of a bead apex rubber, and also to improve steering stability. SOLUTION: This pneumatic tire includes a bead apex rubber 8 having a triangular cross section and extending from a bead core 5 toward the outside in a radial direction. The bead apex rubber 8 is made from a strip wound body 11 formed by spirally laminating and winding a long belt-like rubber strip 10 around a tire rotating shaft i. The radial outer end edge 8e of the bead apex rubber 8 forms an undulating line 12 circumferentially extending undulatedly inside and outside of the radial direction. The radial amplitude Wr of the undulating line 12 is set within a range of 0.05-0.15 times the height of a tire cross section and the number of crests 12U around a tire is set within a range of 8-32. COPYRIGHT: (C)2009,JPO&INPIT
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