织构长宽比对钻头轴承润滑减磨性能的影响

Influence of Texture Aspect Ratio on Lubrication and Antifriction Performance of Bit Sliding Bearing

基于雷诺方程建立单一织构不可压缩牛顿流体润滑条件下的动压润滑理论模型,采用有限差分法和高斯-赛德尔迭代法求解雷诺方程,分析不同长宽比(平行速度方向为长度方向,垂直速度方向为宽度方向)织构表面对动压润滑性能的影响;并采用MMW-1型微机控制万能摩擦磨损试验机开展牙轮钻头滑动轴承模拟工况下的单元摩擦学实验,对比分析不同长宽比织构对销-盘摩擦副表面摩擦磨损性能的影响;综合数值仿真与单元摩擦学实验结果,分析织构长宽比对织构润滑减磨的影响机制。数值仿真结果表明,织构长宽比对织构动压润滑性能的影响与织构深度有较大的关系,织构深度小于最小油膜厚度时,织构长宽比越小,织构的动压润滑性能越好;织构深度大于最小油膜厚度时,织构长宽比越小,织构的动压润滑性能越差。单元摩擦学实验结果表明,不同长宽比织构均能有效提高表面的摩擦学性能,但表现为织构长宽比越小,织构表面抗摩擦磨损性能越好。数值仿真和实验结果的差异在于仿真分析为动压润滑状态,而单元实验研究则为混合润滑状态。

The hydrodynamic lubrication theoretical model of single texture was established based on the Reynolds equation under the lubrication condition of incompressible Newtonian fluid. By solving the Reynolds equation with the finite difference method and Gauss-Seidel iterative method,the influence of textured surface with different aspect ratio（ parallel velocity direction for length and vertical velocity direction for width） on hydrodynamic lubrication performance was discussed. The unit tribology experimental under the simulation condition of rock bit sliding bearing was carried out by using MMW-1 type wear testing machine,the influence of texture aspect ratio on lubrication and tribological properties of textured surface was also discussed. The influence mechanism of texture aspect ratio on texture lubrication and tribological was analyzed by combing the results of numerical simulation and unit tribological experiment. Numerical simulation results show that the influence of texture aspect ratio on hydrodynamic lubrication performance has a great relation with texture depth.When the texture depth is less than the minimum oil film thickness,the smaller the aspect ratio of the texture,the better the dynamic lubrication performance of the texture. When the texture depth is greater than the minimum oil film thickness,the smaller the aspect ratio of the texture,the worse dynamic lubrication performance of the texture. The tribological experimental results show that texture with different aspect ratio can effectively improve tribological properties of textured surface,but the smaller texture aspect ratio,the better the tribological properties of textured surface. The difference between two the result of numerical simulation and the result of unit tribological experiment is that the simulation analysis is based on the hydrodynamic lubrication state,while the unit experimental is based on the mixed lubrication state.