Effect of Stator Surface Texture on the Performances of an Ultrasonic Motor

Aiming at the problem-solving of the severe wear and temperature rise of friction materials used in ultrasonic motors, by using the method of fabricating micro-texture on the stator surface, the mechanical properties of ultrasonic motor was improved and the wear of friction material was reduced. Firstly, the positions of material adhesive area on the stator surface was measured by a microscope. After that three different density textures were designed and fabricated on stator surface by laser. Then, the speed-torque characteristics, efficiency-torque characteristics and temperature rise of the motor were tested. Meanwhile, the stator surface was observed. The results showed that the no-load speed of 3-dimple-texture stator was the highest, which was 12.1% higher than that of smooth stator. The stall torque and efficiency of 5-dimple-texture stator was the highest, which were 13.04% and 17.1% higher than that of smooth stator motor respectively. The temperature rise of textured stator was also reduced. By observing stator surface, it was found that the dimple texture greatly reduced the adhesion of the friction material, which can increase the energy conversion efficiency of the motor contact interface, improved the motor performance and reduced the wear of the friction material.