A Transducer for Micro Cryogenic Actuator using Novel Preload Mechanism without Bolt-clamping

In this study, a transducer for micro cryogenic actuator using novel preload mechanism without bolt-clamping is proposed. The aim of this research is to realize the ultrasonic transducer with a simple structure for applying preload under cryogenic condition to miniaturize the transducer for a micro actuator. As a temperature decreases, the preload is applied to the piezoelectric element by the difference of the thermal expansion coefficients. The finite element method simulation result shows that the preload is effectively applied under the cryogenic condition. We have fabricated and evaluated the proposed type of transducer. The experimental results show that we have successfully applied preload by the proposed structure of the transducer under the low temperature condition.