Investigation of Miniature Cantilever-Type Ultrasonic Motor Using Lead-free Array-Type Multilayer Piezoelectric Ceramics

摘要

We studied the following to clarify the design rule of the miniature cantilever-type ultrasonic motor using lead-free array-type multilayer piezoelectric ceramics, which is (Sr,Ca)_2NaNb_5O_(15). The relationship between the motor properties and stator vibrator dimensions was investigated by the finite element method and vibration analysis. The motor properties mainly depended on the cantilever sizes. The motor properties can be especially controlled from the revolution-speed-oriented type to the torque-oriented type by adjusting the vamplate radius of the cantilever. As a result, the design rule was clarified. In accordance with the design rule, the lead-free torque-oriented motor was fabricated and its properties were evaluated. The driving properties of this motor changed to the torque-oriented characteristics, such as the ratio of the maximum torque to the maximum speed was over 1200-fold of that of the motor fabricated in a previous study. It appeared that the driving properties of the lead-free cantilever-type motor can be controlled by using the design rule.