通过环型超声波电机定转子接触机理分析得到接触表面应力分布,利用摩擦学二项式定理,借助等效预压力分析了接触表面等效摩擦系数的变化,给出了计算定转子接触表面实际摩擦系数的理论模型。对单个波长接触区域内的应力及等效摩擦系数分布进行了计算,得到固定预压力变振幅以及固定振幅变预压力情况摩擦系数的变化。结果表明定子表面质点超声振动的垂直方向位移是摩擦系数降低的根本原因,这为超声波电机摩擦材料的选择和使用提供了理论依据。
Through the study of the contact mechanism of stator and rotor,the normal stress varies in contact region of one wavelength was considered in this paper.Based on binomial theorem of tribology,a mathematical model was deduced to calculate the effective frictional coefficient of USM contact surface and the effective frictional coefficient within one wavelength by some different condition.The results reveal that the vertical displacement of the particle on the stator is the causes of friction reduction and that will be proposed for the choice of frictional materials.