STEEL CORD FOR REINFORCEMENT OF RUBBER MATERIAL AND PNEUMATIC TIRE

摘要

Disclosed is a steel cord for reinforcement of a rubber material which is capable of improving cut resistance when a blunt or a sharp protuberance is trod upon, without reducing the strength in the axial direction of the cord and without increasing the weight of a tire; further disclosed is a tire which uses said steel cord as a reinforcing material. This steel cord for reinforcement of a rubber material has a multitwisted structure formed by at least two-layer structure whereby multiple sheath strands (2) of multiple twisted wires are twisted around one core strand (1) of multiple twisted wires, and the core strand (1) and sheath strands (2) respectively are comprised of a twisted structure of twisted core wires and sheath wires. The relationship expressed by the formula 1.8 ? [(S·cos2a)/{r · (f1 + f 2)}] × 100 ? 4.2 is fulfilled, with f1 being the wire diameter of the outer layer of the strand (1); f2 being the wire diameter of the outer layer of the strand (2); r being the distance between the centers of the strands (1) and (2); S being the cross-sectional area of the strand (2); and a being the twisting angle of the strand (2).