STEEL CORD FOR REINFORCING RUBBER PRODUCT AND PNEUMATIC RADIAL TIRE

摘要

PROBLEM TO BE SOLVED: To obtain a steel cord suitable for reinforcing the belt part of a radial tire by twisting plural element wires on plural parallelly arranged cores to form the outer wall shape of the formed cord into a track shape. SOLUTION: Two or more cores are arranged parallel to each other without being twisted, and plural element wires are twisted on the cores to form the plurally layered twisted steel cord. The outer wall shape of the formed steel cord on a surface vertical to the longitudinal direction of the cord is a track shape comprising a pair of parallel lines and a pair of mutually faced circular arcs. When the element wires of the outermost sheath are placed at the parts of the above parallel wires, the element wires has a distance of <=0.02mm between the adjacent element wires. The major axis (a)mm and the minor axis (n)mm of the cord satisfies the inequalities: 1.00<=(a)/(nc×dc+2×ds)<=1.03 and 1.00<=(b)/(dc+2×ds)<=1.03 [nc is the number of the core element wires; dc is the diameter (mm) of the core element wire; ds is the sum of the diameters of the sheath element wires].