| 摘要 |
PURPOSE: A tire-reinforcing steel cord with excellent rubber penetration and a pneumatic radial tire comprising the steel cord are provided to enhance durability of a tire by enhancing of rubber penetration by giving a shape to at least one or all of seven to eight filaments forming a second core layer. CONSTITUTION: A tire-reinforcing steel cord with excellent rubber penetration comprises a first core layer(1), a second core layer(2) and a wrapping core. The first core layer consists of three filaments(1a). The second core layer consists of seven to eight filaments(2a) and protects the first core layer. The first and second core layers are the same in twisting direction and cycle. At least one of filaments forming the second core layer has a 2D wave shape. The wrapping core consists of one filament protecting the outer circumferential surface of the second core layer. The twisting direction of the wrapping core is opposite to the first and second core layers. |
