摩擦材料应用方式对超声波电机驱动特性的影响

摩擦材料是超声波电机的关键零件,其应用方式直接影响超声波电机的驱动特性.以行波超声波电机为研究对象,将摩擦材料分别应用到转子和定子上,与相应的定子和转子组合,模拟超声波电机的接触方式,研究了超声波电机的负载和磨损特性随摩擦材料应用方式的变化规律.借助于阻抗仪测试了摩擦材料应用到定子齿面前后的阻抗特性,采用精密粗糙度仪和金相显微镜评价了超声波电机定子和转子接触界面磨损前后的形貌变化及其磨损模式.结果表明:当摩擦材料应用到定子齿面时,定子的谐振频率略微降低;当2台超声波电机空载转速相同时,摩擦材料应用到定子齿面与金属转子配副时可获得较大的堵转力矩,定子摩擦材料表面呈现抛光的磨损特征,而当摩擦材料应用到转子表面与金属定子配副时,转子摩擦材料表面呈现较严重的犁沟磨损.

Effect of Application Mode of Friction Material on Driving Characteristics of Ultrasonic Motor

Friction material is one of the most important parts in ultrasonic motor. Its application modes affect directly the characteristics of ultrasonic motor. Using two traveling wave ultrasonic motors which the friction material was applied on rotor and stator, respectively, then the rotor and stator were matched with their corresponding stator and rotor to simulate the contact behavior of ultrasonic motor. The variations of load and wear properties of ultrasonic motor with the application modes of friction material were studied. Impedance characteristics of the stator were measured by impedance analyzer before and post applying on friction material layer. The unworn and worn surface morphologies and surface roughness of contact surfaces of the two ultrasonic motors were studied by metalloscope and JB-4C precision roughness instrument. The wear mechanism was analyzed. The results showed that resonance frequency of stator with friction material on decreased slightly. The motor with friction material applied on stator obtained higher stall torque at two ultrasonic motors without loading at same speed. Polishing wear was the dominant mechanism of the stator with friction material, while ploughing wear was the dominant mechanism of the rotor with friction material.