Vibrator and ultrasonic motor employing the same

摘要

A vibrator for exciting substantially elliptical motion and an ultrasonic motor employing such a vibrator. A vibrator includes a resonant member having a central hole defined therein and a circumferential portion, a first piezoelectric member for exciting circumferential shearing vibration in the resonant member such that the circumferential portion and the hole are positioned at antinodes of the circumferential shearing vibration about the hole, and a second piezoelectric member for exciting vertical vibration or flexural vibration in the resonant member in a direction different from the direction in which the circumferential shearing vibration is excited by the first piezoelectric member. An ultrasonic vibrator has a moving element held against the resonant member in the vibrator.