| 研究実績の概要 |
To improve the performance of polymer-based ultrasonic motors, we developed a triple-layered vibrator, consisting of polymer, fine ceramic, and PZT layers, since the fine ceramics are capable of greatly enhancing the stiffness of the entire vibrator. As predicted, the maximal torque and maximal output power with the triple-layered motor are 5 and 13 times the values of the previous motor with polymer and PZT layers. In addition, since fine ceramics exhibit good vibration characteristics as well as the frictional properties, we employed alumina to fabricate a new type of ultrasonic motors. This 35-mm-diameter ultrasonic motor provides a maximal torque and maximal output power of 1.56 Nm and 26.0 W, respectively, both of which greatly exceed the values achievable with the ultrasonic motors working in the same vibration modes. This study provides a new approach to improve the performance of ultrasonic motors.
In addition to the study regarding ultrasonic motors, we conducted a fundamental investigation on the mechanical attenuation about polymers. Since mechanical attenuation greatly affects the crystallinity degrees of polymers, we carried out thermal annealing on polymers to change their crystallinity degrees. The experimental results show that, in the case of poly phenylene sulfide, its mechanical quality factor increased from 400 to 800 after a 72-hour annealing process at 150 degrees; this validates the effectiveness of our proposal.
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