The principle and structure of a screw drive piezoelectric motor

A new structure of piezoelectric motor is studied, which is driven by ultrasonic power. The motor is composed of a threaded nut and screw. The piezoelectric ceramic is pasted to the nut. The nut will vibrate, similarly to the kind of a ¿Hula Hoop motion¿, under the driven of ultrasonic power. Then the vibration becomes a linear motion by the fiction of the screw and the nut. Based on the theory of vibration of cantilever beam, the principle of the motor has been described. It is found that the trajectory of the particle of the nut is an elliptical motion. According to the design, a prototype was fabricated. Experiments show the speed of the motor can reach 3 mm/s.