本研究以薄盤軸推式超音波致動器來驅動市售風扇，利用有限元素法分析薄盤軸推模態，藉由改變薄盤振動片周界之幾何形狀分析其對軸推模態的影響，設計較佳軸推模態提供致動器的製作，並設計適當的驅動連結提高定子至轉子間的能量傳輸。
本研究所提的軸推模態（3LL-modal）致動器是利用薄盤振動片（直徑41 mm、厚度0.23 mm的蜂鳴片）對其周界施加三個相同長深度的缺口，缺口的分佈角度為110°-120°-130°，並在致動片中央以驅動螺釘將之固定於一基板上。三個相同長深度缺口的設計，使得致動片外緣束縛減少可增加內波環的高度。缺口不對稱分佈的設計，可使內波環的高度更加增強並形成大小不一依特定方向的振動。故藉由3LL-modal致動器的驅動可使立於驅動螺釘上的扇葉快速旋轉。
驅動連結的設計包含驅動接觸面、驅動螺釘的長度、致動器與基板間的連結長度。其中以驅動接觸面的設計，包含接觸圓直徑以及轉軸端球徑，對定子至轉子間能量傳遞的影響最大。
實驗結果證實，3LL-modal致動器可推動直徑75 mm的扇葉旋轉達2250 rpm，消耗功率僅約1.1 W，而直流風扇馬達，在同一扇葉同一轉速下，消耗功率為1.8 W。因此，本研究提出的3LL-modal致動器具有取代直流風扇馬達的能力，且在薄型風扇市場中具競爭潛力。

In this study, driving a fan by a thin-disk shaft-driving type ultrasonic actuator is presented. Shaft-driving modes are designed by changing the geometric shape of a thin-disk vibrator. They are analyzed by finite element method to figure out suitable geometric parameters to construct a new ultrasonic actuator. The driving joint is also well devised to promote the energy transfer from stator to fan rotor.
The proposed 3LL-modal actuator is constructed by a thin-disk vibrator (piezo buzzer element) with three same deep-depth notches, arranged in 110°-120°-130° along the border of the vibrator, and with a driving bolt fastened at vibrator’s center. With three same deep-depth notches, the boundary of the vibrator can be released and the inner deformed height can be increased. Furthermore, by arranging notches in an asymmetric distribution, the inner deformed height can thus be enhanced further in a specific direction. Accordingly, the fan can be spinning quickly upon the driving bolt by the 3LL-modal actuator.
The driving joint’s design involves the driving contact, the length of driving bolt, and the length between actuator and base plate. Among them, the driving contact’s design referring to the contact ring’s diameter and the end shaft’s radius affects crucially the transferred energy from stator to rotor.
Experiential results show that a fan blade with 75 mm diameter can be rotated up to 2250 rpm consumed about 1.1 W by the 3LL-modal actuator. Under the same blade and rotating speed, the power consumption of the DC motor is 1.8 W. Therefore, the proposed ultrasonic actuator demonstrates the ability to substitute for a DC fan motor and the potential to compete in thin-fan market.

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