Vibration wave motor having piezoelectric pressure member

摘要

A vibration wave motor obtains a desired pressure using a piezoelectric device. The vibration wave motor includes a vibrator which is supported by a shaft and has electro-mechanical conversion elements for generating a travelling vibration wave progressing along the circumferential direction around the shaft when a first electrical signal is applied to the vibrator. A rotating unit which has a portion which is in press-contact with a surface of the vibrator, perpendicular to the shaft, rotates around the shaft by the travelling vibration wave generated in the vibrator. A piezoelectric pressure member maintains a desired press-contact between the vibrator and the actuator by a piezoelectric effect generated when a second electrical signal is applied to the piezoelectric pressure member. Thus, a constant pressure can be maintained by detecting the pressure via the piezoelectric pressure member during operation or stop of the vibration motor.