A novel ultrasonic motor with roller interface (RUSM)

This paper presents the development of a new type of traveling wave rotary ultrasonic motor. This motor consists of a metallic ring as the stator, and a piezoelectric ring which is bonded to it, and the cage of thrust needle bearing which is located between stator and rotor. In this type of ultrasonic motor a piezoelectric ceramic excites the metallic ring then the traveling wave of stator surface causes a rotation in the roller, and rollers rotate the rotor respectively. Due to the increase of the contact zones the transition power from stator to rotor and efficiency of motor increase. The operation principle of motor is presented along with theoretical equations. Experimental fabrication and characterization of a sample motor is performed to confirm the concept of roller interface ultrasonic motor.