Abstract: A speed variator comprises a bell-shaped body (5) forming a frustoconical rolling surface (6) able to rotate about its own axis of symmetry (Y), a wheel (7) able to rotate about a second axis (W) and engaged by rolling with the rolling surface (6) to allow the transmission of a driving torque between the wheel (7) and the bell-shaped body (5), and an actuator (9) acting between the wheel (7) and the bell-shaped body (5) for moving the wheel (5) and the bell-shaped body (7) towards and/or away from each other in such a way as to make the wheel (7) engage with different portions of the rolling surface (6). The rolling surface (6) and the second axis (W) converge in a point (P).

Abstract: A speed variator comprises a bell-shaped body (5) forming a frustoconical rolling surface (6) able to rotate about its own axis of symmetry (Y), a wheel (7) able to rotate about a second axis (W) and engaged by rolling with the rolling surface (6) to allow the transmission of a driving torque between the wheel (7) and the bell-shaped body (5), and movement means (9) acting between the wheel (7) and the bell-shaped body (5) for moving the wheel (5) and the bell-shaped body (7) towards and/or away from each other in such a way as to make the wheel (7) engage with different portions of the rolling surface (6). The rolling surface (6) and the second axis (W) converge in a point (P).