Working Principle of Ultrasonic Motors

The working principle of Ultrasonic motor is shown in figure. High order curling vibration is generated on the surface of the elastic vibrator (stator) and travelling eaves are made by excitation of the piezoceramic vibrator. And the certain pressure causes the slider to propagate on stator by the friction between them. Driving force of Ultrasonic motor is obtained by travelling-wave type elastic curling wave. This type of motor is named as travelling wave type Ultrasonic motor. For generating elastic curling wave on the elastic annular plate, adhere the piezoceramic vibrator beneath the annular plate and exploit the expanding and contracting wave. That is piezoceramic vibrator beneath the elastic annular plate is polarized and when AC voltage is applied to the vibrator, sectional expanding and contracting move occurs and elastic curling waves are generated on the elastic annular plate.