MULTILAYER STEEL CORD FOR TYRE CASING

摘要

The invention concerns an unsaturated external multilayer cable, for use as reinforcing element of a tyre casing reinforcement, comprising a core having a diameter d0 enclosed with an intermediate layer (referenced C1) of six or seven wires (M = 6 or 7) of diameter d1 spirally wound together by a step p1, said layer C1 being itself enclosed by an external layer (referenced C2) of N wires of diameter d2 spirally wound together by a step p2, N being less by 1 to 3 than the maximum number Nmax of wires capable of being wound in one ply around the layer C1, said cord having the following characteristics (d0, d1, d2, p1 and p2 in mm): (i) 0.14 < d0 < 0.28; (ii) 0.12 < d1 < 0.25; (iii) 0.12 < d2 < 0.25; (iv) when M = 6: 1.10 < (d0/d1) < 1.40; when M = 7: 1.40 < (d0/d1) < 1.70 (v) 5 pi (d0 + d1) < p1 < p2 < 5 pi (d0 + 2d1 + d2); (vi) the wires of layers C1 and C2 are wound in the same twisting direction. The invention further concerns articles or semi-finished plastic and/or rubber products reinforced with said multilayer cord, in particular tyres for industrial vehicles, more particularly heavy truck tyres and their outer casing reinforcement plies.