A screw-thread-type ultrasonic actuator based on a Langevin piezoelectric vibrator

A novel screw-thread-type ultrasonic actuator based on a Langevin piezoelectric vibrator, with an assembly comprised a threaded shaft, is presented. The bolt-clamped Langevin vibrator consists of 4 chips of PZT ceramics and generates more energy with a certain input power. The threads of the stator multiply the linear force and position resolution, and the threaded rod is rotated directly to achieve linear movement without additional mechanical conversion. The actuator was designed and optimized using the Finite Element Method (FEM), and a prototype was fabricated. At 300 V_p-p, the maximum thrust force, velocity, and efficiency were approximately 4.2 N, 9.5 mm s^-1, and 5.6%, respectively.