将超声电机稳定工作时定、转子接触状况的求解转化成静力分析问题。采用ANSYS的三维点点接触单元,对旋转型行波超声电机接触界面建立了时间域分析模型。将摩擦层等效为一个处于某个周向位置的接触单元,法向简化为单向受压线性弹簧,切向用滑动摩擦或粘滑摩擦来模拟。对接触单元施加节点位移条件求约束反力,得到了接触界面对转子的各向作用力的时间离散量,进而由力平衡关系得到预压力和接触界面的动力输出特性。模拟分析了三维纯滑、三维粘滑、二维纯滑、二维粘滑4种情况下的接触状态,比较了各向接触力与定、转子各向速度之间的关系。
The stable state of contact interface of ultrasonic motor is treated as a static balance problem. For the contact interface of the traveling wave type rotary ultrasonic motor (TRUM) ,a simplified model in time domain is established by the three dimensional point-to-point element using ANSYS. The friction layer is equivalent to the contact element at some circumferential position,and is simplified as a linear spring supporting only compression in the normal direction and pure-slip or stick-slip in the tangential direction. Applying the displacement constraints to nodes of the contact element,the discrete values of the constraint reaction forces in time domain are obtained. Furthermore,output characteristics of TRUM are determined by solving force balance equations. Four conditions,such as,3D pure-slip,3D stick-slip,2D pure-slip and 2D stick-slip are simulated,and the relationships of the contact force and velocities in each direction are determined and compared.