Torque improvement of ultrasonic motor with polymer-based vibrator

为了提高聚合物基超声电机的性能，我们开发了一种三层激振器，由聚合物、精细陶瓷和PZT层组成，因为精细陶瓷能够大大提高整个激振器的刚度。正如预测的那样，三层电机的最大扭矩和最大输出功率分别是聚合物和PZT层电机的5倍和13倍。此外，由于精细陶瓷具有良好的振动特性和摩擦性能，我们使用氧化铝制造了一种新型超声波电机。该35 mm直径超声电机的最大转矩和最大输出功率分别为1.56 Nm和26.0 W，大大超过了超声电机在相同振动模式下所能达到的值。该研究为提高超声电机的性能提供了一条新的途径。除了对超声电机的研究外，我们还对聚合物的机械衰减进行了基础性的研究。由于机械衰减对聚合物的结晶度影响很大，我们对聚合物进行了热退火来改变其结晶度。实验结果表明，以聚苯硫醚为例，在150℃下退火72小时后，其机械品质因子由400提高到800；这证实了我们建议的有效性。

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.