双圆弧谐波减速器共轭啮合区混合润滑分析

Analysis on mixed lubrication at the conjugate meshing domain of harmonic gear with double-circular-arc tooth profile

为了给轮齿啮合区的加速寿命试验提供理论依据,更好地指导产品优化设计,以某型号谐波减速器为分析对象,基于包络理论求出柔轮与刚轮的齿廓方程,分析了啮合点的曲率半径、卷吸速度以及啮合区受载情况,综合考虑啮合区的宏观几何、真实表面粗糙度等因素,建立了柔轮与刚轮啮合区的混合润滑模型,通过分析润滑区膜厚比、摩擦因数等参数,定量研究了转速和温度对润滑性能的影响.结果表明:转速越高,平均油膜厚度和膜厚比越大,接触载荷比和接触面积比越小,润滑性能越好.当转速高于2 200 r/min时,啮合区由边界润滑变为混合润滑,接触载荷比和接触面积比较50 r/min时减小90%以上,摩擦因数减小一半以上,将转速控制在2 200 r/min以上有利于改善润滑状况;随着啮合区温度的升高,平均油膜厚度和膜厚比逐渐减小,接触载荷比和接触面积比逐渐增大,润滑状况逐渐变差.温度为60℃时,摩擦因数较10℃增加一倍以上,接触载荷比和接触面积比增加一倍以上,需严格控制谐波减速器工作温度在60℃以下.

To provide a theoretical basis for accelerated life test and support for product optimization design,the tooth profile equation of the flexible wheel and rigid wheel is derived based on envelope theory. The load condition,curvature radius and volume absorption speed of the meshing area are analyzed. Considering the macroscopic geometry of contact area and the real surface roughness of meshing area,a mixed lubrication model of the flexible wheel and rigid wheel was established. The influence of speed and temperature on lubrication performance was studied by analyzing the film thickness ratio,friction coefficient and other related affecting factors. The results show that,when the speed is higher,the average film thickness and film thickness ratio are greater,the contact load ratio and the contact area ratio are smaller and the lubrication performance is better. When the speed is higher than2 200 r/min,the meshing zone turns from boundary lubrication to mixed lubrication,the contact load ratio and the contact area ratio are reduced by more than 90%,the friction coefficient is reduced by more than half compared to50 r/min. Controlling the speed over 2 200 r/min is helpful to improve the lubrication condition. When the temperature of the meshing zone increases,the average film thickness and film thickness ratio decrease and the contact load ratio and the contact area ratio increase,the lubrication condition deteriorates. When the temperature is at 60 ℃,the friction coefficient,contact load ratio and contact area ratio are more than doubled compared to that at10 ℃. The harmonic reducer＇s working temperature should be controlled below 60 ℃ strictly.