论文部分内容阅读
A novel screw-thread-type ultrasonic actuator based on a Langevin-type piezoelectric vibrator which assembly comprised of a threaded shaft and,engaged,a transducer formed stator therewith is presented.The stator resonator consists of four chips of PZT ceramics,excited using two electrical input with a phase shift of 90 degree,to generate an elliptical motion at the helical portion of the mechanical screw at the first bending mode and to drive the inside threaded rod directly with no backlash.The actuator is not a typical wobbling-type ultrasonic motor but a screw-thread-type linear actuator providing a long stroke corresponding to the length of the threaded rod more than about 30 to 50 millimeters,and its highly suitable for the applications of high accuracy positioning requirement with a relative higher thrust force and lower linear speed due to the Langevin-type resonator structure.