Pulley assembly for a continuously variable transmission

1. A driven pulley assembly for a continuously-variable vehicle transmission, comprising a support element having an axis, a first half-pulley rigidly connected to said support element, a second half-pulley facing said first half-pulley to define a seating adapted to house a drive belt, said second half-pulley being axially and circumferentially mobile in relation to said support element, a cam assembly functionally inserted between a radial peripheral portion of said second half-pulley and a radial peripheral portion of said support element to control the position of said second half-pulley, said cam assembly defining a plurality of circumferential cavities carried by the radial peripheral portion of said second half-pulley and respectively defined by first and second sides disposed crosswise to said axis that act as cam-followers, and further comprising a plurality of cams each of which has a base portion connected to said support element and housed in a corresponding one of the plurality of circumferential cavities wherein each of said cams cooperates selectively with said first and second sides, said first and second sides defining a respective contact surface for a relative portion of each of the plurality of cams and converging towards said first half pulley, and each of said plurality of cams further including deformable shock-absorbing material mounted over said base portion so as to be positioned within the plurality of circumferential cavities to attenuate impacts in the circumferential direction with the deformable shock absorbing material being interposed with circumferential play between two stops defined by the first and second sides, respectively, thereby delimiting the maximum relative motion along the circumferential direction between the first and second half-pulleys.

2. The pulley assembly as claimed in claim 1 , further including an elastic element which cooperates axially with said second half-pulley to push said second half-pulley towards said first half-pulley.

3. The pulley assembly as claimed in claim 2 , further including a thrust bearing inserted between said elastic element and said second half-pulley.

4. The pulley assembly according to claim 2 , further including a cup-shaped support, which supports said cams, rigidly connected to said support element, and cooperating with said elastic element.

5. The pulley assembly as claimed in claim 2 , wherein the cam is positioned outwardly of said elastic element.

6. The pulley assembly as in claim 2 , wherein the elastic element is a spring.

7. The pulley assembly as claimed in claim 1 , further including a spacer ring which is fitted to one of said first and second half-pulleys, housed in a seating facing the other of said first and second half-pulleys and positioned so that the spacer ring is radially inside said seating.

8. A driven pulley assembly for a continuously-variable vehicle transmission, comprising:

a support element having an axis,

a first half-pulley rigidly connected to said support element,

a second half-pulley facing said first half-pulley to define a seat adapted to house a drive belt, said second half-pulley being axially and circumferentially mobile in relation to said support element,

a cam assembly functionally inserted between a radial peripheral portion of said second half-pulley and a radial peripheral portion of said support element to control the position of said second half-pulley, said cam assembly defining a plurality of circumferential cavities carried by the radial peripheral portion of said second half-pulley and respectively defined by first and second sides disposed crosswise to said axis that act as cam-followers, and comprising a plurality of cams each of which is connected to said support element and housed in a corresponding one of the plurality of circumferential cavities,

wherein each of said cams cooperates selectively with said first and second sides, said first and second sides defining a respective contact surface for the relative cams, and

further including deformable shock-absorbing material within the plurality of circumferential cavities that cooperates with said cam assembly to attenuate impacts in the circumferential direction with the deformable shock absorbing material being interposed with circumferential play between two stops defined by the first and second sides, respectively, thereby delimiting the maximum relative motion along the circumferential direction between the first and second half-pulleys,

wherein said deformable shock-absorbing material is carried by said cams and that said cams are mobile with respect to said support element, and

wherein each of said cams further include a cap that defines an internal cavity which houses a tooth integral with said cup-shaped support and a body made of the deformable shock-absorbing material interposed between said tooth and said cap, at least in the circumferential direction inside said internal cavity.

9. The pulley assembly as claimed in claim 8 , wherein said cap defines a circumferential slot which houses a pin element rigidly connected to said tooth.

10. The pulley assembly according to claim 8 , wherein said deformable shock-absorbing material comprises an elastomer material.