Abstract
In this study, a small ultrasonic motor which is driven at a cryo temperature has been fabricated and evaluated. The motor consists of a bolt-clamped Langevin-type transducer (BLT), a rotor, a bearing, a spring, and a casing. The maximum diameter and the height of the motor are 22mm and 30.5mm. The ultrasonic motor has been evaluated in the room temperature and in the cryo helium gas. The relationship between contact pre-pressure of the rotor to the BLT the continuously rotating temperature is indicated. The rotation speed was 553 rpm at the room temperature and 65.4 rpm at the 4.5K helium gas.
