An Introduction to Ultrasonic Motors

An account of ultrasonic motors - a new type of electric motor which employs the piezo-electric effect to give the motive power (rather than electromagnetic interactions in conventional motors). One of the authors, Sashido, is the inventor of the ultrasonic motor.

The ultrasonic motor, invented in 1980, utilizes the piezoelectric effect in the ultrasonic frequency range to provide the motive force. (In conventional electric motors the motive force is electromagnetic). The result is a motor with unusually good low-speed high-torque and power-to-weight characteristics. It has already found applications in camera autofocus mechanisms, medical equipment subject to high magnetic fields, and motorized car accessories. Its applications will increase as designers become more familiar with its unique characteristics.This book is the result of a collaboration between the inventor and an expert in conventional electric motors: the result is an introduction to the general theory presented in a way that links it to conventional motor theory. It will be invaluable both to motor designers and to those who design with and use electric motors as an introduction to this important new invention.