制御可能な出力軌道を持つ新しいモード選択可能な圧電超音波トランスデューサーの設計と性能

This study presents a novel mode-selectable piezoelectric ultrasonic transducer (PUT) with a traditional sandwich structure, developed through systematic integration of modular design, electro-mechanical equivalent four-terminal network method, modal optimization techniques, and vibration conversion principles. To evaluate the performance of the proposed PUT, a prototype was fabricated and underwent a series of comprehensive excitation tests. Experimental results indicate that the PUT exhibits two fundamental mechanical resonance modes: a lower-frequency mode characterized by longitudinal-bending (L-B) coupled vibration, and a higher-frequency mode corresponding to pure longitudinal (L) vibration. The proposed transducer enables flexible and seamless switching among the L mode, L-B coupled mode, and a hybrid mode that incorporates both fundamental vibrations, while maintaining excellent energy conversion stability and efficiency during prolonged operation. By adjusting the voltage amplitudes of different frequency components in a dual-frequency composite excitation signal, the vibration at the transducer's working end can be switched among rectilinear, elliptical, and parallelogram-like trajectories. This enables direct control over the ultrasonic energy action zone. The unique combination of mode-selectable and trajectory-control capabilities gives the proposed transducer significant potential for ultrasonic-assisted precision manufacturing applications.