变位齿轮齿条传动的热弹流润滑分析

Analysis of Thermal Elastohydrodynamic Lubrication of Modified Gear Rack Transmission

建立了齿轮齿条传动的热弹流润滑模型,考虑齿轮热效应和正负变位齿轮沿啮合线在不同啮合点的综合曲率半径变化、卷吸速度的变化和单双齿啮合引起的载荷变化,分析齿轮齿条传动机构在不同瞬时、载荷随时间变化的非稳态弹流润滑数值解。讨论了变位系数对齿轮齿条弹流润滑油膜压力和膜厚的影响并分析了正变位和负变位对中心膜厚和最小膜厚的影响规律。结果表明,正变位可以降低油膜压力,增加膜厚,改善齿轮齿条机构的润滑状态;负变位使油膜压力升高,膜厚变薄。因此,设计齿轮齿条传动机构时,在符合要求的前提下,应尽量选择正变位齿轮,避免选择负变位齿轮。

The elastohydrodynamic lubrication model of gear rack transmission is established,considering the gear that is modified and thermal effect,comprehensively considering the variation of equivalent radius of curvature,entrainment velocity and the alternating load along the line of action and the gear tooth modification,the numerical solution of unsteady-state elastohydrodynamic lubrication of the gear rack with time-dependent loads is analyzed. The influence of modified coefficient on the oil film pressure and film thickness of the gear rack is studied and the influence of positive modification and negative modification on central film thickness and minimum film thickness are also analyzed. The results show that the positive modification could reduce the oil film pressure and increase the film thickness which could improve the lubrication of the gear rack,negative modification causes the oil film pressure rises and the film thickness become thinner. Therefore,in order to in accordance with the requirements of the premise when designing the gear rack mechanism,the positive modification gear should be selected to avoid the negative modification gear.