A Cylindrical Micro-Ultrasonic Motor Using Micromachined Bulk Piezoelectric Vibrator with Glass Case

Abstract

A cylindrical piezoelectric vibrator 0.8 mm in diameter was fabricated by micromachining. In this paper, a micro ultrasonic motor 1.8 mm in casing diameter that uses this micro-machined cylindrical bulk piezoelectric vibrator is introduced. This motor consists of the piezoelectric vibrator, a glass case, a bearing, and a rotor. The vibration velocity of the cylindrical vibrator was 715 mm/s when the driving frequency was 69 kHz and the driving voltage was 40 Vp–p. Since the stator transducer is fixed at the end of the cylinder, it is easy to support the vibrator, and the motor has a simple structure. In addition, the vibrator and rotor were supported by glass case. As the case was made of glass, a suitable vibration mode of the driving of the motor was obtained. We have fabricated and evaluated the cylindrically shaped traveling micro-ultrasonic motor using this vibrator.