Abstract
A shear mode rotary ultrasonic motor (USM) with high torque and low speed characteristics using alkaline niobate based lead-free piezoelectric ceramics was fabricated and characterized. Two vibrator pairs composed of four ceramic substrates were set perpendicularly. When alternative voltage independently was applied to each vibrator, a rotational motion was generated at the top part of stator of USM. By the finite element method, the motor's vibration modes and driving mechanism were analyzed. On the basis of the analysis result, the USM was fabricated and showed a maximum speed of 238 rpm under applied AC voltage of 70 Vrms
