Improvement of operation time, torque and out-gassing performance of UHV compatible rotary feedthrough utilizing ultrasonic motor

As requirements for mechatronic operation in a vacuum condition increases, the significance of the ultrasonic motor as a vacuum compatible actuator becomes larger. Previously, the authors introduced a vacuum compatible rotary feedthrough utilizing ultrasonic motor technology and succeeded in its operation in vacuum conditions. However, its torque generation, lifetime and out-gassing performances were not satisfying. In this paper, tuning of resonance and modification of friction materials are performed as solutions for these problems. As a result of these measures, the maximum torque generation and operation time were improved by a factor of 9 and 25, respectively. In addition, increase of gas pressure during operation was decreased.