| 主权项 |
1- Tire with a radial carcass reinforcement comprising a crown reinforcement formed of at least two working crown layers of reinforcing elements, crossed from one layer to the other making with the circumferential direction angles of between 10° and 45°, itself capped radially by a tread, the said tread being connected to two beads via two sidewalls, the crown reinforcement comprising at least one layer of circumferential reinforcing elements, characterized in that the reinforcing elements of the said at least two working crown layers have a diameter less than 1.1 mm and in that they satisfy the following relationships:
(Fr×4 cos2 α)/(P×0.75 Pg×Ø)<5, Fr1/(P1×sin|α1|)≧1.2 Fr2/(P2×|α2|)where Fri is the breaking force of the reinforcing elements of layer i measured on reinforcing elements taken from the tire and expressed in daN,
Fr=(Fr1+Fr2)/2 is the mean breaking force of the said at least two layers, αi is the angle formed between the reinforcing elements of the working crown layer i and the circumferential direction at the equatorial plane, α=(|α1|+|α2|)/2 is the mean angle of the said at least two layers, Pi is the distribution spacing, at the equatorial plane, of the reinforcing elements of the working crown layer i, expressed in mm, P=(P1+P2)/2 is the mean spacing of the said at least two layers, Pg is the nominal inflation pressure of the tire, expressed in daN/mm2, Ø is the internal diameter of the tire measured in the equatorial plane and expressed in mm. |
