Piezo-electrostatic step actuator

摘要

A piezo-electrostatic actuator comprises a stator (S), a movable member (R) which is guided parallel to the stator (S) and electrostatic cilia (9) which are associated with the stator (S) with the interposition of piezoelectric means (A) which can be activated by applying voltage pulses so as to cyclically assume a first configuration in which the cilia (9) come in contact with the movable member (R) so as to adhere thereto by electrostatical effect due to the application of a voltage pulse, and a second configuration, in which the cilia (9) move away from the movable member (R) while remainig connected thereto, so as to impart a step to the movable member (R) in the direction of its movement. Adjacent to the cilia (9), between the stator (S) and the movable member (R) there is interposed a spacing member (10) which is secured to the stator (S) and is in sliding contact with the movable member. Below the spacing member (10) there is arranged a second piezoelectric actuator (B) which can be activated so as to impart a reciprocating movement to the spacing member (10) towards and away from the movable member, with a phase opposite to that of the first piezoelectric actuator (A) carrying the cilia (9), so as to amplify the movement of the movable member (R) imparted by the cilia (9). In one variant, the cilia (9) are carried by a blade which is supported in a cantilever fashion between the stator and the movable member parallel thereto, and is provided with piezoelectric means which cause a cyclical deflection thereof towards and away from the movable member.