Effects of wear of friction material on performance of ultrasonic motor

Friction material is one of the key components in an ultrasonic motor. The wear of the material affects the contact friction and output performance of the motor. A method which utilizes the equivalent wear of friction material to simulate the wear during operation is proposed based on the wear characteristics of the ultrasonic motor's contact interface. A relationship between wear and performances of the ultrasonic motor is constructed. The influences of wear on output performance, friction coefficient of the contact interface, and wear morphology are researched in the experiments. According to the experiment's results, with wear of friction material ( decreasing thickness), the output performance of the ultrasonic motor presents a downward trend, the friction coefficient between contact interfaces decreases gradually, the friction-reducing ratio between contact interfaces increases gradually, and the wear between contact interfaces decreases. The results are helpful to understand operating performance, design, and select friction material of ultrasonic motor.