Driving characteristics of ultrasonic motor with different application mode of friction material

Friction material is one of the most important parts for ultrasonic motor. The characteristics of ultrasonic motor were affected directly by application modes of friction material. Two friction couples were prepared to simulate the contact behavior on two traveling wave ultrasonic motors. One friction couple is composed of rotor with friction material layer and metal stator; the other friction pair is composed of metal rotor and stator with friction material layer. Impedance characteristics of the stator were measured by impedance analyzer. Based on the two traveling wave ultrasonic motors, the variations of friction drive and wear properties of the two ultrasonic motors were studied. The pre and post surface morphology and surface roughness of contact interface of the two friction couples were investigated by metalloscope and JB-4C precision roughness instrument, respectively. The wear mechanism of contact interface was analyzed. The results showed that the resonance frequency of stator with friction material layer decreases slightly. The motor with friction material layer stator obtains bigger stall torque. Ploughing wear characteristic was the dominant wear mechanism and wear of contact interface of the motor with friction material layer rotor was more severe than the motor with friction material layer stator.