Development of a novel piezoelectric micromotor

A new rod-shaped travelling wave piezoelectric micromotor is developed. In the micromotor, five pieces of piezoelectric ceramics clamped by 2 metal cylinders are used as its stator. The driving principle of the rod-shaped piezoelectric motor is simulated. The stator structure and the position to lay these piezoelectric ceramics are calculated to improve the electro mechanical conversion efficiency. A flexible rotor is designed to reduce the radial slip between the stator and rotor and to improve the motor efficiency. The prototype motor and its micro-driver tested. The motor is 9 mm in out-diameter and 15 mm in length and 3.2 g in weight. When the motor operates with its first bending mode (72 kHz) of the stator, its maximal speed and torque reach 520 rpm and 4.5 mNm. Results show that the motor has good stability. The speed fluctuation is controlled within 3% by the frequency automatic tracking technique.