Abstract: In order to analyze and suppress sharp noise of the traveling-wave ultrasonic motor (TWUSM) during its operation, the test measuring system of motor noise is established, and the source of noise is analyzed through test by using finite element method (FEM). The vibration interpretation model of the generation mechanism of motor noise is established by using the equivalent principle. On the basis of the model, the influence of pre-pressure on the motor noise is analyzed, and methods and measures for reducing the motor noise are proposed. Research results show that the motor noise is caused by self-exciting vibration due to friction between the stator and the rotor, and the noise intensity decreases along with the increase of pre-pressure. When pre-pressure exceeds the critical value, the motor noise can be well suppressed.

Key words: Mechanism, Noise, Self-exciting vibration, Test, Ultrasonic motor