Linear displacement actuator

The present invention relates to actuators and deals more particularly with linear displacement actuators. The subject of the invention is a linear displacement actuator which includes a male part and a female part. One part includes a screw thread and the other part includes at least one peripheral rib which collaborates with the screw thread. The inside diameter of the female part, increased by the depth of the screw thread, is greater than the outside diameter of the male part. The female part bears linear actuators arranged at right angles in a support and is free to be displaced axially with respect to the male part. The linear actuators place the female part in sinusoidal vibration in two perpendicular directions with an appropriate phase shift between the vibrations, and displaces, rotation-wise, the line of contact between the screw thread and the at least one peripheral rib. The screw thread and the peripheral rib remain motionless in terms of rotation and therefore bring about relative linear displacement of the female part and of the male part.