Abstract: A speed variator pulley provided with reduced flexion removable rings is used in a variable speed transmission of the V pulley type, provided with a trapezoidal belt. Transmissions of this type are, for example, used in snow scooters, motorcycles, utilitarian or pleasure vehicles or cars without permit or of the TQM type. The pulley of the invention has an arrangement which makes it possible to reduce the axial friction forces which are the cause of a hysteresis effect in the operation of the pulley.

Abstract: A driving pulley of a variable speed transmission having a drive shaft and two coaxial cheeks facing one another and defining a v-shaped groove which receives a trapezoidal belt. One of the cheeks is axially movable relative to the other cheek and has two housings distributed around its axis. The housings have a linear oblique ramp secured thereto and side wings which act as radial translation guides for inertia blocks which bear against the ramps and against a reaction cup attached to a hub of the driving pulley. The movable cheek is made solid in rotation with the drive shaft by a rubber membrane having a bow shape which is connected to the reaction cup. As the drive shaft rotates, the inertia blocks are subject to centrifugal forces which cause the movable cheek to move toward the other cheek. A return spring provides a force opposing the movement of the movable cheek.