Ultrasonic motor with a vibrator having recesses

摘要

An ultrasonic motor has a circular vibrator and a mover which is pressed into contact with the circular vibrator. A circular elastic member which constitutes the circular vibrator has a uniform thickness along a circumferential direction thereof, and has a plurality of recesses on a face of the circular elastic member opposing the mover. According to the above structure, uniform elastic travelling waves are generated in the circular elastic member of the vibrator, and a uniform contact is attained between the vibrator and the mover, and yet the development of cracks at bottoms of the recesses is prevented. A ring-like recess is provided on another elastic member which constitutes the mover.