基于载荷分担理论的渐开线斜齿轮热混合弹流润滑分析

沿接触线把斜齿轮分成许多小薄片,每一薄片看成具有当量角速度的直齿轮,根据欧拉方程得到任一接触点处的曲率半径和表面速度.然后基于载荷分担、弹流润滑和粗糙线接触理论,建立了考虑表面粗糙度的斜齿轮传动混合热弹流润滑模型.研究了斜齿轮传动稳态载荷分布下牛顿流体和Carreau流体时的润滑特性.结果表明:牛顿流体和Carreau非牛顿流体模型下,中心油膜厚度、油膜承载比例、油膜温升随时间和接触线的变化规律相同.牛顿流体下的摩擦系数较工程实际偏大.Carreau非牛顿流体模型下摩擦系数和工程实际相符,其随接触线啮合位置的变化规律与油膜厚度正好相反.

Mixed Thermoelastohydrodynamic Analysis of Helical Gears Based on Load Sharing Concept

The helical gears were discretized into many small segments along the contact line and each segment was viewed as a spur gear with an equivalent angular velocity.The radii of curvatures and surface velocities in the direction that was normal to the contact line were obtained through Euler's equation. The mixed thermal EHL model of helical gear was built based on load sharing concept, elastohydrodynamic lubrication theory and rough line contact theory. The performance of helical gears with rough surfaces with considering thermal effect was predicted using Newtonian model and Carreau rheological model, respectively. The results show that variations of the film thickness, portion of load carried by film and film temperature rise with the meshing time and the contact line calculated by the two rheological models were identical. The friction coefficient calculated by Newtonian model was beyond the project reality. The friction coefficient calculated by Carreau rheological model matched with the project reality and its variation with meshing position along the contact line was contrary to the variation of film thickness.