WANG Jian GUO Jifeng

(College of Electrical Engineering, Zhejiang University  Hangzhou 310027)

Received Jul.4, 2007

Revised Aug.30, 2007

Abstract Cylindrical Ultrasonic Motor (CUSM) can be widely used in many fields such as zoom and focus system of cameras, electric curtain and micro-driver of MEMS. This work concentrates on the single-point and the double-point contact modes between the stator and the rotor, which are proved by theory and experiment. There is a critical point of the pre-pressure. When the pre-pressure is below the critical point, the single-point model is suitable; otherwise the double-point model is appropriate. Then the force transferring model is analyzed, and expressions of mechanical characteristics and efficiency of the motor are put forward. Simulation results are confirmed by experimental ones, which shows that the model is well suited to guide design of the motor. Finally a??14 mm prototype was fabricated. Its maximum torque is 0.11 Nm, and the no-load speed is about 300 r/min.

PACS numbers: 43.35