Piezoelectric motor with means for delivering information about the position and/or the rotational speed of the rotor

摘要

The piezoelectric motor (10) has mechanical oscillation of the rotor (20) or stator (20) used to provide cyclic movement of at least one active surface (19a-c) of the oscillated component cooperating with a passive surface (21) of the other component, to provoke the relative movement between them. The passive surface has a number of zones with a periodically varying acoustic impedance, causing a corresponding variation in the electrical impedance of the motor, detected across the motor terminals for evaluation of the relative position between the rotor and the stator.