Tire having a softened carcass reinforcement

1. A tire for a heavy goods vehicle, having

a radial carcass reinforcement comprising a crown reinforcement formed of at least two working crown layers of reinforcing elements that are crossed from one layer to another, forming angles of between 10° and 45° with the circumferential direction,

said crown reinforcement itself being capped radially with a tread, said tread being joined to two beads by way of two sidewalls,

the radial carcass reinforcement additionally comprises, in each shoulder, an axially outer end of a layer of additional reinforcing elements that are mutually parallel in the layer and are oriented circumferentially,

wherein said axially outer end of said layer of reinforcing elements that are mutually parallel in the layer and are oriented circumferentially is axially outside said at least two working crown layers, and

at least one additional protective layer is axially interposed between the layers of additional reinforcing elements, an axially inner end of each respective additional reinforcing layer that are mutually parallel in the layer and are oriented circumferentially being axially in line with an axially outer end of the at least one additional protective layer, of reinforcing elements

wherein the reinforcing elements of the carcass reinforcement have a diameter less than 0.85 mm, and wherein said reinforcing elements of the carcass reinforcement are made up of threads with a diameter less than 0.16 mm, and

wherein the crown reinforcement, which is supplemented radially on the outside by the at least one additional layer, the reinforcing elements being 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 which is radially adjacent thereto.

2. The tire according to claim 1 , wherein the metal reinforcing elements of at least one layer of the carcass reinforcement are cords, advantageously non-wrapped cords, that return a flow rate less than 20 cm 3 /min in what is referred to as the permeability test.

3. The tire according to claim 1 , wherein the metal reinforcing elements of at least one layer of the carcass reinforcement are cords comprising at least two layers and wherein at least one inner layer is sheathed with a layer consisting of a polymer composition, such as a non-crosslinkable, crosslinkable or crosslinked rubber composition.

4. The tire according to claim 1 , wherein, in a radial plane, the ratio between the thicknesses of rubber compound between the inner surface of the tire cavity and that point of a metal reinforcing element of the carcass reinforcement that is closest to said inner surface of the cavity, of the two parts of the tire profile that are centered on the respective orthogonal projections onto the inner surface of the tire cavity of the axially outer ends of the additional layer of reinforcing elements that are mutually parallel in the layer and are oriented circumferentially, and of the parts of the tire profile that have the smallest thicknesses, is greater than 1.15.

5. The tire according to claim 1 , wherein the crown reinforcement comprises at least one layer of circumferential reinforcing elements between two working crown layers.

6. The tire according to claim 5 , wherein the reinforcing elements of said at least one layer of circumferential reinforcing elements are metal reinforcing elements that have a secant modulus at 0.7% elongation of between 10 and 120 GPa and a maximum tangent modulus of less than 150 GPa.

7. The tire according to claim 1 , wherein the crown reinforcement further includes a triangulation layer formed of metal reinforcing elements that form angles of more than 50° in absolute terms with the circumferential direction.

8. The tire according to claim 1 , wherein the metal reinforcing elements of at least one layer of the carcass reinforcement are cords comprising at least two layers and wherein at least one inner layer is sheathed with a layer consisting of a polymer composition, such as a non-crosslinkable, crosslinkable or crosslinked rubber composition based on at least one diene elastomer.