几何修形对低速圆柱滚子轴承混合润滑性能的影响研究

针对圆柱滚子轴承直母线滚子在接触出现的边缘应力集中现象，采用对滚子进行几何修形的方法，运用拟动力学分析方法开展轴承滚子受力和相对运动关系分析. 在此基础上，综合考虑轴承接触工况、滚子修形参数和真实表面粗糙度等因素，建立圆柱滚子轴承混合润滑数学模型，分析滚子修形参数和转速对轴承润滑性能的影响. 结果表明:从润滑角度判断，滚子母线凸度量δ和滚子端头圆角半径r均存在一个优化区间，使得最大受载滚子接触表面最大油膜压力和次表层最大von Mises应力σ显著减小，边缘效应弱化；δ和r对中心膜厚h_c和摩擦系数f的影响较小；转速的增大会使h_c变厚，f_c和σ减小，且混合润滑状态下转速对修形滚子的σ变化显著，修形后的滚子较未修形的滚子润滑性能要好. 

Geometric Modification on Mixed Lubrication Performance of Low-Speed Cylindrical Roller Bearing

Specific to the stress concentration at the edges of straight generatrix shape roller in cylindrical roller bearing, the method of geometric modification on roller was used. The forces acting on a roller and the relative motion for the bearing were carried out with the quasi-dynamic analysis method. By considering the contact conditions, roller modification parameters and real surface roughness, a mixed lubrication model was established. The effect of different roller modification parameters and speeds on the lubrication performance of bearing were calculated. The results from the judgement of lubrication show that both the roller convexity and roller round corner radius at roller ends, δ and r, having the optimized range to make the maximum oil film pressure and subsurface maximum von Mises stress (σ) decreased significantly, and weakened the edge effect. The δ and r had insignificant effect on average film thickness at center (h_c) and friction coefficient (f). With an increase rotation speed of the bearing, the h_c increased while the f and σ decreased, and the effect of the rotational speed on the δ of modified roller appeared to be significant in the mixed lubrication status. Compared to the roller without modification, roller with modification showed better lubrication performance.