一种基于纵弯夹心式换能器的直线超声电机

该电机利用夹心式换能器激励纵向和弯曲振动，通过一定相位差，在驱动足上形成椭圆振动轨迹。采用了指数形变幅杆放大纵振振幅以提高电机速度。利用经典换能器变幅杆理论确定换能器和变幅杆尺寸和纵向谐振频率，并辅以有限元方法来简并纵向和弯曲振动频率。驱动足处于变幅杆不同位置时驱动椭圆振动轨迹有所不同。用有限元法研究了不同形态的椭圆振动轨迹对电机输出性能的影响，发现当驱动足位于弯曲驻波波腹处电机性能最稳定。样机的最大速度480mm/s，最大推力25N。

Ultrasonic Linear Motor Using Longitudinal and Bending Multimode Bolt-clamped Langevin Type Transducer

The proposed motor forms elliptical trajectories on driving tips by exciting longitudinal and bending vibration of a double mode Langevin type transducer with input phase difference.Exponential shape transducer horn is adopted to achieve high linear speed.Classical theory of transducer horn is used to determine transducer's longitudinal resonance frequency and configuration dimensions.Combined with FEM design method,the longitudinal and bending resonance frequencies are degenerated.The different locations of driving tips on the horn caused different elliptical trajectories,and how variation influence on motor mechanical output is studied through FEM method.The motor got best performance when positioning driving tips on antinodes of the bending wave. Typical output of the prototype is no-load velocity of 480mm/s and maximum thrust force of 25N.