Ultrasonic motor driven by elliptic vibration

摘要

An ultrasonic motor composed of a cylindrical stator having a vibration converting member and a cylindrical rotor slidably rotatable on the stator. Ultrasonic longitudinal vibration is generated in the stator by imposing high frequency voltage on piezoelectric elements disposed in the stator. A part of the longitudinal vibration is converted into twisting vibration by operation of slits formed on the vibration converting member. Both the longitudinal and twisting vibrations are compounded into elliptic vibration which drives the rotor. The vibration converting member is made by laminating a number of element plates each having cut-out portions or by combining several divided blocks. The slits are automatically formed on the vibration converting member without being machined, when the vibration converting member is formed by assembling the element plates or the divided blocks.