【作者】 孙浩洋；

【导师】 陈晓阳； 王文；

【作者基本信息】 上海大学 ， 机械设计及理论， 2005， 博士

【摘要】 工程中应用十分广泛的滚子类摩擦副通常在润滑条件下工作,其压力分布、膜厚膜形及温度分布对机器零部件的性能和寿命有很大影响,需进行凸度设计以改善此类摩擦副的承载能力和润滑状况。本文以滚子类摩擦副为应用对象,研究了有限长线接触弹性流体动力润滑问题,探讨了凸度滚子的稳态热弹流设计和动态等温特性,考察了润滑剂、载荷、速度等工况参数和凸度修形参数对压力分布、膜厚膜形、温度分布的影响,讨论了加减速、起停、急停以及摆动等特殊变速运动下的压力分布和成膜特性。完成的主要工作如下:一.基于多重网格技术,通过引入附加项强制构造温度分析矩阵主对角优势,限制压力温度的合理范围以及对于苛刻工况由工况参数接近的相对温和工况的计算结果提供良好初值等数值技巧,构建了适用于有限长线接触热弹流分析的高效稳定的计算方法,可在接触长宽比达到100,接触压力达到2.0 GPa的苛刻工况下得到收敛解。以此为工具,系统完整的定量模拟了Wymer等在此领域完成的经典光干涉试验,分析结果与试验结果吻合很好,从而验证了分析程序的正确性。二.系统深入分析了工程中常用的相交圆弧修形滚子的重载稳态热弹流特性,包括此种滚子的两个修形参数:修形长度和修形半径的影响;速度、载荷和滑滚比等工况参数的影响;Eyring非牛顿效应的影响;并探讨了弹流温度场与压力场分布规律的相似性以说明凸度设计对弹流温度分布的影响。研究表明:只要修形参数合适,相交圆弧修形滚子将分别在修形起始位置以及靠近轴向出口位置出现两次轴向颈缩,轴向颈缩与径向颈缩共同阻碍了润滑油流出接触区从而增加膜厚,即“封油效应”。合理修形的此类滚子可对工况有较好的自适应性,从成膜的角度讲,润滑失效与“封油效应”的无法建立是对应的;端部的压力集中程度主要由修形半径和载荷决定。使用Eyring非牛顿流体有利于改善此类接触副的承载能力和润滑状况,但Eyring非牛顿效应对这种滚子的凸度设计没有明显影响。压缩功是导致弹流温度梯度与压力梯度相似性的主要原因。凸度设计在改善压力分布的同时也将改善温度分布,进而改善由热效应导致的各种疲劳现象。更多还原

【Abstract】 The widely used line contact friction pairs work mostly under lubrication conditions. The pressure, film thickness, and temperature distributions play important role in the performance and service life of such friction pairs. Therefore, crowning design is necessary to increase their load capacity and improve lubrication condition. In this dissertation, the line contact EHL of finite length is studied. Crowning designs based on steady thermal and transient isothermal EHL of profiled rollers are discussed. The effects of lubricants, applied load, velocity as well as crowning parameters on pressure, film thickness and temperature distributions are investigated. The pressure distribution and oil film structure of several types of non-steady state motion, including acceleration/deceleration, stop/start, rapid deceleration and oscillation are obtained. The main work is as follows:1. An effective, robust and stable algorithm is established based on the multi-level multi-integration technique and several numerical skills: introducing additive items to construct the temperature matrix, constricting the pressure and temperature in a reasonable range during the calculation process, and using the solutions of some similar operating conditions as the initial values for more severe operating conditions. Numerical trials show that convergent solutions could be obtained under severe working conditions (the contact pressures exceed 2.0 GPa and the length-width ratio of contact area is over 100). Using this algorithm, systematic and complete numerical simulations of the classical interferometry experiments by Wymer’s group are carried out. The numerical and experimental results agree quite well with each other. Therefore, the reliability of the calculation program is verified.2. The steady thermal EHL behavior for cylindrical rollers with crown-profiled ends at heavy load is systematically analyzed, including the following aspects: the effects of crowning length and crowning radius; the effects of velocity, applied load and slip-slide ratio; and the effects of the Eyring non-Newtonian fluids. Moreover, the similarity of the pressure and temperature distribution is investigated to discover the influence of the crowning design on the temperature distribution. It has been concluded that, if the crowning parameters are suitable, such rollers could establish two times of constriction in the cylindrical direction, the更多还原