Design of a novel type ultrasonic motor for high torque generation

A novel type ultrasonic motor is proposed. Newly designed motor consists of two stators and a rotor. Each stator is stacked up both sides of ring type rotor. Hence, the driving force transmitted to the rotor enlarges and higher torque can be produced from the proposed motor. Particularly, this motor need not install any spring device. Rotor structure is designed especially to deliver the created pressure when the stator vibration occurs. Its stall torque was 1.4 Nm and no-load speed was 92 rpm respectively. The highest efficiency was 7.5 % at about 55 % of stall torque and the maximum mechanical output power was 3 W. The applied driving voltage condition was 80V(rms) at 44.5 kHz. From the experiment results, the torque enlargement was realized in proposed model in comparison with the commercial motor. However, the performance for revolution speed, mechanical output and efficiency was inadequate relatively. If the repletion is achieved through the succeeding study, the proposed model would contribute to the expansion of ultrasonic motor application scale.