Tire for Heavy Vehicles Having a Crown Reinforcement Comprising a Complex Strip
A tire comprising a crown reinforcement formed of at least two working crown layers of reinforcing elements itself radially capped by a tread strip, the tread strip being connected to two beads via two sidewalls. At least two working crown layers are formed by circumferential winding of a complex strip formed of two layers including continuous reinforcing elements passing from one layer to the other, the said reinforcing elements being parallel within a layer and crossed from one layer to the other at angles with respect to the circumferential direction that are identical in terms of absolute value.
1 . A tire comprising a crown reinforcement formed of at least two working crown layers of reinforcing elements, itself radially capped by a tread strip, said tread strip being connected to two beads via two sidewalls, wherein at least two working crown layers are formed by circumferential winding of a complex strip formed of two layers including continuous reinforcing elements passing from one layer to the other, said reinforcing elements being parallel within a layer and crossed from one layer to the other at angles with respect to the circumferential direction that are identical in terms of absolute value.
2 . The tire according to claim 1 , wherein the radial distance between the respective reinforcing elements of each of the crown layers forming a complex strip is less than the thickness of a crown layer.
3 . The tire according to claim 1 , wherein the reinforcing elements of the said complex strip make an angle of between 10 and 45° with the circumferential direction.
4 . The tire according to claim 1 , wherein the complex strip is wound circumferentially with an axial overlap.
5 . The tire according to claim 1 , wherein the complex strip is wound circumferentially to form juxtaposed turns.
6 . The tire according to claim 1 , wherein the reinforcing elements of the complex strip are made of metal.
7 . The tire according to claim 6 , wherein the reinforcing elements of at least one layer of circumferential reinforcing elements are metal reinforcing elements having a secant modulus at 0.7% elongation of between 10 and 120 GPa and a maximum tangent modulus of less than 150 GPa.
8 . The tire according to claim 1 , wherein the reinforcing elements of the complex strip are made of a textile material.
9 . The tire according to claim 1 , wherein the reinforcing elements of the complex strip are made of a hybrid material.
10 . The tire according to claim 1 , wherein the crown reinforcement comprises at least one layer of circumferential reinforcing elements.
11 . The tire according to claim 1 , wherein the crown reinforcement is supplemented radially on the outside by at least one supplementary layer, known as a protective layer, of reinforcing elements know as elastic elements, oriented with respect to the circumferential direction at an angle of between 10° and 45° and in the same direction as the angle formed by the inextensible elements of the working layer radially adjacent to it.
12 . The tire according to claim 1 , wherein the radial distance between the respective reinforcing elements of each of the crown layers forming a complex strip is less than half the thickness of a crown layer.
13 . The tire according to claim 1 , wherein the complex strip is wound circumferentially with an axial overlap, equal to at least half the width of said complex strip.