DISPOSITIVO DI TRASMISSIONE A VITE-MADREVITE AD ATTRITO VOLVENTE, EDATTUATORE LINEARE COMPRENDENTE TALE DISPOSITIVO.

摘要

A linear actuator comprises an electric motor (2) and a screw-and-nut transmission device in which the nut member comprises a planet-carrier member (9) driven in rotation about the axis of the screw (3), and at least one planet (14) mounted so that it is free to turn on the planet-carrier member (9) about an axis (15) that is parallel to and set at a distance from the axis (3a) of the screw (3). The planet (14) has a plurality of collars (16) set in planes perpendicular to the axis of the screw (3) which engage respective portions of the bottom of the thread of the screw (3), in such a way that, as a result of the rotation of the planet-carrier member (9), the planet (14) rolls around the screw (3) forcing the latter to translate axially due to the engagement of each collar (16) against the sides of the respective portion of the thread of the screw.