混合弹流润滑系统的建模与摩擦学特性研究  

A Mixed Elasto-Hydrodynamic Lubrication Model for Studying Tribological Properties of Rough Surfaces

作　　者：董国忠 张辉[1] 李月 董光能[1] DONG Guozhong;ZHANG Hui;LI Yue;DONG Guangneng(Key Laboratory of Education Ministry for Modem Design and Rotor Bearing System, Xi’an Jiaotong University, Xi’an 710049, China;Zhuzhou CRRC Times Electric Co., Ltd., Zhuzhou, Hunan 412001, China)

机构地区：[1]西安交通大学现代设计及转子轴承系统教育部重点实验室,西安710049 [2]株洲中车时代电气股份有限公司,湖南株洲412001

出　　处：《西安交通大学学报》2018年第1期107-114,共8页Journal of Xi'an Jiaotong University

基　　金：国家自然科学基金资助项目(51475358;51705400)

摘　　要：为了研究粗糙表面微凸体对混合弹流润滑区摩擦学特性的影响,建立了考虑粗糙表面微凸体的弹流润滑数学模型,可呈现粗糙表面的局部接触状态。通过生成虚拟粗糙表面,分别利用K-E弹塑性接触模型和平均流量雷诺方程计算微凸体接触压力与流体动压力,并且利用快速傅里叶变换技术计算基体的弹性变形量;通过绘制润滑系统的Stribeck曲线,研究了虚拟微凸体、名义载荷、综合粗糙度和微凸体曲率半径对弹流润滑摩擦学特性的影响。结果表明:微凸体的接触压力产生基体弹性变形,使膜厚增加,导致流体动压力减小,微凸体承载比和摩擦因数增大;名义载荷增加导致低速时摩擦因数变小,润滑状态在更低速条件下从边界润滑过渡到混合润滑;综合粗糙度的减小会使Stribeck曲线向左移动;微凸体曲率半径的增大仅使润滑状态加快从边界润滑过渡到混合润滑,然而对从混合区域过渡到弹流区域几乎没有影响。To investigate the influence of asperities on tribological properties in mixed elasto hydrodynamic lubrication(EHL),a numerical model which can present the local contact state of the rough surface is developed.This model can produce a virtual rough surface in Gaussion distribution,and with the use of average flow Reynolds equation and the K E elasto plastic model,the hydrodynamic pressure and the contact pressure can be predicted,respectively.Fast Fourier transform(FFT)method is used to compute the elastic deformation of substrate.The influences of virtual asperities,nominal load,roughness and asperity curvature radius on the tribological properties of EHL are also discussed through plotting corresponding Stribeck curves and film thickness shapes.The results show that the contact of asperities induces the deformation of substrate,which subsequently increases the film thickness and reduces the hydrodynamic pressure.Thus,the load rate of oil film and the friction coefficient are increased accordingly.With the increase of nominal bearing load,the friction coefficient is decreased at low speed,implying that the transition point from boundary lubrication regime to mixed lubrication regime occurs at lower speeds.Smaller roughness implies the movement of the Stribeck curves towards left.The increase of asperity curvature radius accelerates the transformation from boundary lubrication to mixed lubrication.However,the transition from mixed lubrication to hydrodynamic lubrication seems not to be obviously influenced by the asperity curvature radius.

关 键 词：摩擦学 混合弹流润滑 粗糙表面 建模 

分 类 号：TH117.2[机械工程—机械设计及理论]