| 摘要 |
PROBLEM TO BE SOLVED: To provide a pneumatic tire reduced in a bead core weight while favorably maintaining a fitting characteristic against a rim and its manufacturing method. SOLUTION: A bead core rigidity coefficient K computed by an expression (1):K=((H<SB>0.4</SB>-H<SB>0.2</SB>)/(0.4%-0.2%))/S (H<SB>0.2</SB>is extending force (N) in 0.2% distortion, H<SB>0.4</SB>is extending force (N) in 0.4% distortion, and S is a steel wire total cross-section area (mm<SP>2</SP>) of the bead core respectively), satisfies a relation of K≥250 (N/1% distortion/mm<SP>2</SP>) when measuring the extending force and the distortion in extending the bead core 5 of a single body in diameter by extracting the bead core 5 from the tire, on the pneumatic tire burying the ring bead core 5 formed by continuously winding one or a plural number of steel wires W in a bead part 3. COPYRIGHT: (C)2008,JPO&INPIT
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