Hemsel T, Wallaschek J
Heinz Nixdorf Institut, Mechatronik und Dynamik, Universitat Paderborn, Germany.
Ultrasonics. 2000 Mar;38(1-8):37-40. doi: 10.1016/s0041-624x(99)00143-2.
Piezoelectric ultrasonic motors have been investigated for several years and have already found their first practical applications. Their key feature is that they are able to produce a high thrust force related to their volume. Beside rotary drives like the travelling wave motor, linear drives have also been developed, but only a few are presently commercially available. In the present paper, we first describe the state of the art of linear piezoelectric motors. The motors are characterized with respect to their no-load velocity, maximum thrust force, efficiency and other technical properties. In the second part, we present a new motor, which is judged to be capable of surpassing the characteristics of other piezoelectric motors because of its unique design which allows the piezoelectric drive elements to be pre-stressed in the direction of their polarization. The piezoelectric elements convert energy using the longitudinal d33 effect which allows an improved reliability, large vibration amplitudes and excellent piezoelectric coupling. Energy loss by vibration damping is minimized, and the efficiency can be improved significantly. Experimental results show that the motor characteristics can be optimized for a particular task by choosing the appropriate operating parameters such as exciting voltage, exciting frequency and normal force.
压电超声电机已被研究多年，并已找到其首个实际应用。其关键特性在于，相较于其体积，它们能够产生较大的推力。除了行波电机等旋转驱动外，线性驱动也已得到发展，但目前只有少数几款在市场上有售。在本文中，我们首先描述线性压电电机的发展现状。这些电机通过其空载速度、最大推力、效率及其他技术特性来表征。在第二部分，我们介绍一种新型电机，因其独特的设计能使压电驱动元件在其极化方向上受到预紧力，所以被认为能够超越其他压电电机的性能。压电元件利用纵向d33效应转换能量，这使得可靠性提高、振动幅度增大且压电耦合良好。通过振动阻尼产生的能量损耗降至最低，效率可显著提高。实验结果表明，通过选择合适的运行参数，如激励电压、激励频率和法向力，可针对特定任务优化电机特性。
