Piezoelectric Motor Utilizing an Alumina/PZT Transducer

Abstract

To enhance the torque and output power of the rod-shaped piezoelectric rotary motors, in this article, we employ alumina to substitute the metal parts of the transducers considering that the high Young's modulus of alumina may avoid preload-induced vibration reduction and enable the transducers to generate the high driving force. Besides, alumina exhibits a relatively low density compared to most of the materials commonly used as the vibrating bodies (except aluminum alloy); this probably enhances the power densities of the piezoelectric motors. To assess the validity of our proposal, we constructed a Langevin-type alumina/lead–zirconate–titanate (PZT) motor and investigated its load characteristics. The transducer of 35 mm in outer diameter operated in orthogonal bending (B2) modes and drove the rotor with its end surface. The alumina/PZT motor yields the maximal torque and maximal output power of 1.56 N·m and 26.0 W, respectively, both of which exceed those of the metal/PZT motors having identical structure and working in B2 modes. Additionally, its power density reaches 56.3 W/kg, relatively high among the rod-shaped rotary motors although some of which work in more powerful modes. This article validates the effectiveness of our proposal and provides a new approach to improve the performance of the rod-shaped piezoelectric rotary motors.