The steel code for rubber additional strength and production manner null of the inflated radial tire which uses

摘要

PPROBLEM TO BE SOLVED: To provide a steel cord for reinforcing rubber, providing improved rubber penetrability into the inside of the cord without reducing tensile modulus, and having improved durability; and to provide a method for producing a pneumatic radial tire using the steel cord. PSOLUTION: The steel cord has a three-layer structure obtained by simultaneously twisting a first layer A including at least one wire 11, a second layer B positioned on the outer periphery side of the first layer A and including a plurality of wires 12, and a third layer positioned on the outer periphery side of the second layer B and including a plurality of wires 13. An unvulcanized rubber formulation R is inserted between the first layer A and the second layer B, and at least the wires 13 of the third layer C are formed. The formed rate of the wire 13 positioned at the top of the third layer C is 90-105%, and the formed rate of the wire 13 not positioned at the top of the third layer C is 95-110% based on the cord diameter DSB1/SBat the top of a cord outline formed when the whole wires 11-13 are arranged in the close-packed state and the cord diameter DSB2/SBnot at the top. PCOPYRIGHT: (C)2008,JPO&INPIT