表面形貌参数γ的一种简易估算法

在部分膜弹流润滑理论研究中,人们已认识到不仅表面粗糙度而且表面形貌参数γ也对油膜厚度及其承载力起着重要作用。因此,本文就此提出了一种方便、实用的表面形貌参数γ的简易估算法。     

点接触弹性流体动力润滑的数值求解

针对以往在固定网格上求解点弹流数值解要花费很长计算机时的问题，采用在较粗网格上精确求解后再向细网插值并以此作为细网初始的技巧求解了点弹流全膜下的数学模型，计算结果表明，应用该技巧较往直接迭代可节省三分之二的ＣＰＵ时间。     

考虑润滑状态的齿轮传动优化设计

根据弹性流体动力润滑理论,考虑齿轮传动过程中轮齿的润滑状态,对斜齿圆柱齿轮传动进行优化设计。计算结果表明,有用优化方案能有效地改善轮齿的润滑性能,阻缓齿轮失效,延长使用寿命。     

滚动轴承摩擦力矩的弹性流体动压润滑计算

探讨了滚动轴承摩擦力矩的弹性流体动压润滑计算 ,并通过实例计算证实其正确性。     

修形后双圆弧圆柱蜗杆传动的点接触弹流计算

根据齿轮啮合原理，共轭曲面原理及弹流理论，对经可控修形的双圆弧齿圆柱蜗杆副进行了点接触分析。计算出了接触点处的最小、最大诱导法曲率及接触点处的最小油膜厚度和最大赫兹应力。探讨了曲率修正量系数，齿根修正量系数对接触点处最小油膜厚度，最大赫兹应力及椭圆接触区椭圆率的影响。给出了曲率修正量系数、齿根修正量系数的合理选择区间。     

计入薄壁构件挠度变形的线接触弹流润滑分析

由于薄壁构件在受力情况下产生挠度变形,对弹流润滑有一定影响,导致原来的弹流润滑计算存在较大误差,经典的接触模型已不再适用。提出一种考虑薄壁平板挠度变形的弹流润滑线接触模型,该模型能够确切反映薄壁平板的挠度变形对弹流润滑的影响;采用有限元仿真软件建立薄壁平板的挠度变形模型,在挠度变形的基础上,分析速度参数及载荷参数对线接触弹流润滑性能的影响。研究结果表明:挠度变形对薄壁件润滑的影响十分明显,油膜压力减小,中心膜厚分布范围增大,膜厚值减小;随着速度及载荷参数发生变化,油膜压力及膜厚也相应地发生改变;当其他条件不变时,中心油膜厚度随速度的增加而增大,且中心油膜区域逐渐增加,速度参数对油膜压力影响较大,油膜压力随着速度的增加而升高,颈缩现象逐渐出现;油膜压力随着载荷的增大而升高,同时油膜厚度逐渐减小。     

Effect of coatings on thermal conditions of EHL

The thermal EHD model of rectangular contact has been applied to analysing the effect of coatings on thermal conditions in EHL. The model takes into account variation of oil viscosity along and across the oil film according to the Barus formula. The solution has been obtained by means of the Newton-Raphson method. The effect of the coating has been examined by comparison of the temperature distributions in the oil film and on the surfaces of rollers for the cases with and without coating. In addition, the oil film shapes and minimum values, the pressure distributions and traction coefficients, have also been compared.     

Development of an improved method for investigating the frictional properties of lubricants under transient EHD conditions

In the design and evaluation of mechanical system performance it is important to know the frictional qualities of the lubricant. Without correct numerical treatment of the lubricant during simulations of large systems, e.g., drive trains in trucks and buses, the results will, to a large extent, be inaccurate. However, obtaining detailed information places demands on the test equipment as the events are both transient and highly loaded. Under quasi‐static conditions, forces are measured with force transducers, but in elasto‐hydrodynamically lubricated conjunctions, where pressures are so high that the surrounding surfaces deform elastically, this cannot be done without permanently damaging the equipment. The conceptual design of the test equipment must therefore incorporate the measuring process in transient conditions (loading‐unloading times of 200–500 μs) being performed in real time, and allow extreme pressures of up to 3 GPa without component destruction. One way to obtain accurate friction data successfully is to apply a concentrated force pulse to a non‐instrumented surface and to measure the response from that pulse elsewhere. The development of a measurement technique, the Lulea ball and bar apparatus, which utilises wave propagation theory, is presented in this paper. An oblique impact on a robust end plate on a rod was used to generate both non‐dispersive compression waves and dispersive flexural waves. The normal force created by the axial wave was measured using strain gauges, while the transverse force was derived from the fast Fourier transforms of two lateral acceleration histories, using dynamic beam theory. The relation between the normal and tangential force histories showed the frictional properties at the impact as a function of time. A variety of lubricants was also studied at Hertzian pressures of up to 2.5 GPa, and the development of the method and results are presented. Experiments indicate that different lubricants exhibit different frictional properties and that the resolution in the test equipment is sufficient to indicate this.     

弹流润滑圆柱滚子轴承径向刚度的计算

针对滚动轴承刚度计算方法存在的问题,对圆柱滚子轴承受力和弹性变形进行了分析,得出了静态工况下滚动轴承的刚度计算式.在此基础上,将有关弹性流体动力润滑理论引入轴承刚度计算过程,以Dowson-Higginson油膜厚度公式为依据,研究了油膜厚度对轴承刚度的影响,推导出了用于计算圆柱滚子轴承径向刚度的数学公式,实例计算表明,该计算方法具有更高的计算精度.     

基于多重网格法的超高速电主轴轴承内部润滑状态分析

本文以超高速电主轴内部主轴轴承为研究对象,基于稳态等温点接触弹流润滑理论,采用多重网格法,对超高速时在不同工况和几何参数等条件下主轴轴承内部的弹流油膜状态进行了分析计算,得出了速度、预载荷等工况条件和接触角、套圈沟曲率半径系数、材料参数等对轴承内部球滚动体与套圈滚道之间润滑状态的影响结果。