一种L形大推力板结构直线超声电机

An L-Shaped Plate Type Linear Ultrasonic Motor with Large Thrusts

为了在扁平作动空间内有效地提高超声电机的输出性能,研制了一种板结构直线超声电机。该电机包括由2个相互垂直的矩形板振子组成的L形定子和直线导轨,利用两振子弯曲振动所形成的对称和反对称模态,通过两相模态切换,实现电机的双向运动。首先,运用有限元方法分析了前端盖开槽对驱动足振幅的影响,通过开设一道圆弧槽增加驱动足处的振幅;其次,研究了振子的螺栓紧固方式对压电陶瓷中预应力的影响,针对矩形板振子结构扁平、横向尺寸大的特点,在振子横截面中部两侧各采用1根螺栓进行紧固,以提高预应力的大小和分布的均匀性;最后,制作样机并开展了实验研究。实验结果表明,电机最大空载速度为435mm/s,最大推力达100N,推重比为54.6。

To improve the mechanical output performance of the ultrasonic motor in flat space,a plate type linear ultrasonic motor is proposed.The motor is composed of a linear guide and an L-shaped stator which is constructed by two mutually perpendicular rectangular plate vibrators.The symmetric and antisymmetric modes of stator based on the bending vibration are utilized,and each mode is excited individually to move the linear guide in one direction.The influence of a slot in the front end cover on amplitudes of driving foot is analyzed,and a slotted front end cover is adopted to enlarge the amplitudes.Then the effect of bolt clamping method of vibrator on the prestress in piezoelectric ceramics is discussed.In the view of the flat structure and large transverse dimension of the vibrator,a bolt is used on both sides of the center of cross section to fasten the vibrator and to improve the value and uniformity of the prestress.Prototypes are fabricated and experimentally investigated.Their typical output performance is that the maximum no-load speed reaches 435 mm/s and maximum thrust reaches 100 N,achieving a thrust-to-weight ratio of 54.6.