Piezoelectric ultrasonic motor using longitudinal-torsional composite vibration of a cylindrical resonator

Abstract

A piezoelectric ultrasonic motor, which uses longitudinal and torsional composite vibration of a cylindrical resonator, was investigated. It was found that the resonant frequencies for longitudinal mode and torsional mode could coincide with each other in the cylindrical resonator, according to finite element analysis and experimental measurement. The motor using both resonant vibrations showed good performance. The 20-mm-diameter motor exhibited a 4 kgf-cm maximum torque, a 450-r.p.m maximum rotational speed, and a 40% maximum efficiency.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>