Design and characteristics of the ultrasonic motor using extensional vibration mode

Ultrasonic motors using extensional vibration mode were designed and fabricated with three compositions, . The piezoelectric ceramic was directly contacted to the shaft without elastic body to transfer the vibration of the piezoelectric ceramics. The problem of adhesion between the piezoelectric ceramics and the elastic body in the stator was eliminated. The properties of the ultrasonic motor, such as the revolution speed and the temperature rise during the operation were measured. The temperature was inversely proportional to the mechanical quality factor of the piezoelectric ceramics. The maximum revolution speed of the ultrasonic motor was achieved at the resonant frequency.