Thermal characteristics of traveling wave rotary ultrasonic motors

This paper mainly reports the thermal characteristics of traveling wave rotary ultrasonic motors. A theoretical model for calculating the power loss of this motor in rated operation is built. The power loss mainly consists of three parts, i.e. the friction loss power which shares the large portion in the total loss, the structure damping loss power and the dielectric loss power. The finite element method is applied to solve the temperature distribution in the ultrasonic motors. The radiation factor for heat dissipating is also taken into account in order to use much more accurate boundary conditions for simulation. The calculated result agrees with the experimental results basically, which indicates that the analysis method in this paper is valid. Besides that, it is found that the uniformity of temperature field of ultrasonic motors can be optimized by changing the dimensions of some structural parts.