Introduction of roller interface ultrasonic motor (RIUSM)

This paper presents the development of new type of traveling wave rotary ultrasonic motor. This motor consists of a metallic ring as the stator, piezoelectric ring bonded to it, and the cage of thrust needle bearing located between stator and rotor. In this type of ultrasonic motor, piezoelectric ceramic excites the metallic ring, then the traveling wave of stator surface causes the rollers to rotate, and rollers rotate the rotor, respectively. 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 (RIUSM).