汽车轮毂轴承脂润滑理论与润滑失效机理研究

发布时间：2018-04-02 21:19

本文选题：轮毂轴承　切入点：脂润滑理论　出处：《华南理工大学》2013年博士论文

【摘要】：随着工业技术的不断发展，零部件高温、重载和高速剪切的使用工况已经十分普遍，从而对润滑剂的性能和相关理论研究的要求也越来越高。经过大量学者的共同努力，对于润滑油及其润滑理论的理论研究，在面、线和点接触的润滑理论以及试验测试装置研制方面都取得了较多成果，并从宏观和微观两个方向全面研究了润滑油润滑机理，对润滑油的应用产生了积极影响。汽车轮毂轴承作为汽车关键零部件，通常采用润滑脂作为润滑剂，而润滑脂由于其特殊的结构和性质，在实际应用和理论研究方面均与润滑油具有较大的差别。目前，润滑脂相关研究主要侧重于应用方面，即高性能润滑脂和相关添加剂的研制，而方法主要是依据经验和大量的试验研究，相关研究尚处于较不完善阶段。因此，探讨润滑脂的润滑机理和完善润滑脂润滑理论，并将相关的理论研究结果应用于实际应用中，尚有许多问题亟需解决。本文首先从推导一般形式脂润滑Reynolds方程出发，，针对轮毂轴承失效统计分析中出现的润滑失效，分析了润滑因素在轴承寿命和使用性能中所起的作用；然后归纳总结出了轮毂轴承润滑失效最终的表现形式，即滚道表面缺陷和润滑脂中存在杂质颗粒；最后，通过理论计算和试验方法，研究了表面缺陷和固体颗粒对脂润滑弹流润滑的影响。因此，本文对脂润滑弹性流体动力润滑理论的研究，轴承失效分析以及润滑脂添加剂的应用具有一定的指导意义。本文的研究工作主要有以下几个方面： 1、推导了适用于润滑脂润滑Reynolds方程的普遍形式，针对不同脂润滑问题给出了相对应的脂润滑方程简化形式。 2、对失效轮毂轴承进行了统计，并分析了润滑对轮毂轴承寿命的影响以及由于润滑不良导致的几种轮毂轴承失效形式。针对内圈随轴转动、外圈固定的轮毂轴承，出现内圈相比于外圈疲劳破坏和磨损更为严重的现象，利用脂润滑弹流理论进行了解释。 3、研究了表面缺陷对脂润滑弹流润滑油膜压力和油膜厚度的影响，并通过实验方法对数值计算结果的正确性进行了验证。采用数值计算方法分析了滚道表面出现凹坑和凸起时，其尺寸和位置对线接触和点接触脂润滑弹流润滑油膜压力和油膜厚度分布的影响，并通过对轮毂轴承表面凹坑和凸起的边缘和中心进行电镜扫描和能谱元素分析证明了数值计算结果的正确性。 4、详细推导了润滑脂存在固体颗粒时的线接触和点接触脂润滑Reynolds方程。利用试验方法和统计学理论分析了轮毂轴承润滑脂中杂质颗粒的来源以及颗粒数量与颗粒粒径的关系，并在此基础上分析了固体颗粒中心位置、速度和尺寸对线接触脂润滑弹流润滑油膜的影响以及固体颗粒速度和尺寸对点接触脂润滑弹流润滑油膜的影响。 5、分析了不同物理属性、不同粒径和质量分数的微纳米颗粒对润滑脂润滑性能的影响。为避免润滑脂添加剂对试验结果的影响，自制了一种不含添加剂的复合锂基润滑脂作为基础脂，给出了基础脂的配方和制备工艺流程。并在基础脂中加入不同粒径、质量分数的硬质脆性颗粒SiO2和软质塑性颗粒Cu作为试验样品，利用四球摩擦磨损试验机测试了润滑脂样品的摩擦系数和试验温度随时间变化的关系。
[Abstract]:With the development of industrial technology , the working conditions of high temperature , heavy load and high speed shearing of lubricating oil have become more and more common .

In this paper , based on the derivation of general form grease lubrication Reynolds equation , the lubrication failure in the statistical analysis of hub bearing failure is analyzed , and the function of lubrication factors in bearing life and service performance is analyzed .
Then , the final form of the lubrication failure of the hub bearing is summarized , that is , the surface defects of the raceway surface and the presence of impurity particles in the grease ;
At last , the influence of surface defects and solid particles on the lubrication of grease - lubricated elastic fluid is studied by theoretical calculation and experimental method . Therefore , this paper has some guiding significance to the research of the theory of elastohydrodynamic lubrication , the failure analysis of bearings and the application of lubricating grease additives . The research work of this paper mainly includes the following aspects :

1 . The general form suitable for lubricating grease lubrication Reynolds equation is deduced , and the simplified form of grease lubrication equation is given for different grease lubrication problems .

2 . The influence of lubrication on the life of wheel hub bearing and the failure form of several kinds of wheel hub bearings caused by poor lubrication are analyzed , and the phenomenon that inner ring is more serious than the outer ring fatigue damage and wear is caused by the rotation of inner ring with the shaft , and the theory of grease lubrication is explained .

3 . The influence of surface defects on the pressure and oil film thickness of lubricating oil film on grease lubrication is studied , and the correctness of the numerical results is verified by the experimental method . The influence of the size and position on the pressure of lubricating oil film and the thickness distribution of oil film are analyzed by numerical calculation method , and the correctness of the numerical results is proved by scanning electron microscope and energy spectrum element analysis on the surface pits and the center of the hub bearing .

4 . The line contact and the point contact grease lubrication Reynolds equation in the presence of solid particles in lubricating grease are derived in detail . The source of impurity particles and the relationship between the number of particles and the particle size are analyzed by means of the experimental method and the statistical theory .

5 . The influence of different physical properties , different particle size and mass fraction on the lubricating performance of lubricating grease was analyzed . In order to avoid the influence of lubricating grease additive on the lubricating performance of lubricating grease , a compound lithium - based lubricating grease without additives was designed as the base grease , and the formulation and preparation process of the base grease were given . The relationship between the friction coefficient of the lubricating grease sample and the test temperature over time was tested by using four - ball friction wear testing machine .

【学位授予单位】：华南理工大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TH117.2

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