| 主权项 |
1. A tire with a radial carcass reinforcement comprising a crown reinforcement, itself capped radially by a tread which is connected to two beads by two sidewalls, wherein reinforcing elements of at least one layer of the radial carcass reinforcement are non-wrapped multilayer metal cords with an unsaturated external layer, comprising a core (denoted C0) of diameter d0 surrounded by an intermediate layer (denoted C1) of four to seven threads (M=4, 5, 6 or 7) of diameter d1 wound together in a helix at a pitch p1, this layer C1 being itself surrounded by an external layer (denoted C2) of N threads of diameter d2 wound together in a helix at a pitch p2, N being 1 to 3 less than the maximum number Nmax of threads that can be wound in a layer around the layer C1, the non-wrapped multilayer metal cords having the following characteristics (d0, d1, d2, p1 and p2 being in mm):
(i) 0.14<d0<0.28; (ii) 0.12<d1<0.25; (iii) 0.12<d2<0.25; (iv) for M=4:0.40<(d0/d1)<0.80;
for M=5:0.70<(d0/d1)<1.10;for M=6:1.10<(d0/d1)<1.40;for M=7:1.40<(d0/d1)<1.70; (v) 5π(d0+d1)<p1<p2<5π(d0+2d1+d2); (vi) the threads of the layers C1 and C2 are wound in the same direction of twisting,wherein the cords return in what is referred to as the permeability test a mean flow rate less than 4 cm3/min and at least 2 points of zero flow rate over a length of 2 cm. |
