超声马达转子摩擦材料磨损特性研究

利用MPX－200型销－盘摩擦磨损试验机和自制的超声马达摩擦特性模拟试验台，考察了摩擦材料在普通滑动试验和超声马达试验条件下的磨损性能，研究了接触预压紧力和负载力矩对转子摩擦材料磨损状态的影响，并借助于扫描电子显微镜和光学显微镜对摩擦材料磨损机理进行分析，指出可用绝对转差率Sf描述超声马达定子和转子相对滑动摩擦磨损程度。结果表明，摩擦材料在超声马达试验条件下的磨损状态与普通滑动试验条件下的不同，普通滑动试验时摩擦材料磨损表面形成了层状覆盖膜，而超声马达转子摩擦材料磨损表面无覆盖膜，其表面呈现犁沟磨损和疲劳剥层磨损特征，这种磨损特征随预压紧力和负载力矩变化而变化，与绝对转差率Sf有关，且存在2个临界转变区。

Study on Wear Properties of Rotor Friction Material of Ultrasonic Motor

The wear characteristics of a rotor frictional material of ultrasonic motor (USM) were investigated on a pin on disc wear tester and a simulating friction characteristic tester of USM under common sliding and USM testing conditions, respectively. The effects of contact pre pressure and load torgue on the wear properties of the rotor frictional material were examined. The wear mechanisms of the rotor frictional material were analyzed based on scanning electron microscopic and optical microscopic observations of the worn surface morphologies. It has been found that the wear characteristics of the rotor frictional material under USM testing condition are different from that under common sliding testing condition. Namely, transfer film is observed on the worn surface of the rotor frictional material subject to common sliding testing, while the worn surface under USM testing condition is smooth and has no transfer film thereon, which is characterized by plowing and fatigue peeling. These features varied with the pre pressure and load torgue, which was correlative to the absolute ratio S f , of the speed difference. It was supposed that S f could be used to express the degree of the relative sliding friction between the stator and rotor of the USM. At S f <0.3, the frictional material surface is relatively smoother and characterized by slight fatigue peeling wear. At S f >0.51~0.6, it is characterized by serious plowing.