RUBBER ARTICLE-REINFORCING STEEL CORD AND PNEUMATIC TIRE

摘要

Provided is a rubber article-reinforcing steel cord having enhanced durability against the so-called cut which is a notch or a pierced hole produced when a tire treads on a dull or sharp protrusion. The enhanced durability is obtained without reducing the strength in the axial direction of the cord and without increasing the thickness of the cord in the radial direction thereof, that is, without increasing the weight of the tire. Also provided is a tire to which the rubber article-reinforcing steel cord is applied as the reinforcing material. A rubber article-reinforcing steel cord having a multiple twisting structure in which sheath strands (2) each formed by twisting element wires together are wound around a single core strand (1) formed by twisting element wires together, the core strand (1) comprising at least a three-layer twisting structure formed by twisting core filaments and sheath filaments together. The lowest breaking tensile strength (bs) of filaments among the filaments which constitute the steel cord and the breaking tensile strength (Bc) of the steel cord satisfy the relationship of bs/Bc × 100 = 0.65.