| 摘要 |
PROBLEM TO BE SOLVED: To obtain a steel cord having a good rubber penetration into its inside, capable of increasing the stiffness of the crossing direction to the rotating direction of a tire while decreasing the stiffness in the rotation direction of the tire and a good fatigue properties to compression and bending, and excellent in production and handling properties. SOLUTION: This steel cord consists of one core wire 1 having almost a spiral state small kink and three side wires 2 having the same wire diameter, the wire 1 has the almost spiral kink having kink pitch P1 (mm) and an outer diameter d1 (mm) in its short diameter direction satisfying the following equations (1) and (2) and the core wire 1 appears between the side wires positioning at the both sides by putting the longer diameter of an approximate ellipse in between, in an almost P1 pitch distance, and the flatness ratio (percentage of T/W) of the approximate ellipse is 38-60%. Equation (1): P1=0.1P-0.5P, Equation (2): T-d1=0.05-0.15.
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