Ultrasonic motor

摘要

An ultrasonic step motor is provided with a stator and rotor. The rotor has a plurality of projections extending in the direction of the stator so that contact is made between the rotor and the stator creating a frictional force to drive the rotor. Vibrators are formed from a piezoelectric material directly attached to the stator. The ultrasonic motor further includes a drive control apparatus for impressing standing waves to the vibrating elements of the vibrator causing a change over to the phase or carrying out an ON-OFF operation of the ultrasonic motor.