Rubber article-reinforcing steel cords and pneumatic tires using such steel cords

摘要

A steel cord is disclosed, which has a core-sheath double layer structure having a 2+7 cord construction or a 2+8 cord construction. A twisting direction of the core is the same as that of the sheath, a forming rate Rc of filaments of the core is 103 to 120% and a forming rate Rs of filaments of the sheath is 102 to 115%. A pneumatic radial tire using such steel cords in a belt layer is also disclosed.