Abstract: A traveling wave piezoelectric motor having essentially a stator (1) in the form of an annular plate PLANE, the stator connected to two groups of cylindrical polarized ceramic piezoelectric elements (2, 3, 4) and excited by an alternating current with a phase shift of 90 degrees between the groups so as to generate a deformation in the form of a traveling wave at the surface of the stator, and of a rotor in the form of a disk. The piezoelectric elements are connected to the stator by the intermediary of an auxiliary coupling piece (5, 6, 7) in the form of a truncated segment and in permanent contact with the stator by their small-section extremity.

Abstract: Traveling-wave piezoelectric motor comprising at least one rotor (20, 21), at least one annular stator (27, 28) and two groups of piezoelectric elements (29) dispersed around the stator, in permanent contact with the stator and excited by an alternating current with a .pi./2 phase shift between the groups so as to produce, at the surface of the stator, a traveling wavelike deformation. Piezoelectric elements consist of mutually independent polarized ceramic bars (29) arranged perpendicularly to the stator and each connected to the stator by an articulation (14).

Abstract: The stator of the motor comprises a support structure bearing at least one pair of transducers each including a vibrating element, the transducers being located colinearly and excited so their vibrating elements vibrate at one and the same frequency, but with a phase shift of 90.degree., and a coupling shell to which the vibrations are applied, and at least one rotor frictionally driven by the coupling shell. The coupling shell is of closed shape and is fixed at two opposed points on its major axis to the transducers. The resonance frequency of the coupling shell is the same in both vibration modes so that high efficiency is obtained.