全油膜润滑条件下磨粒磨损特性的实验研究

本文应用最新研制的ＭＭＵ－５型流体润滑摩擦磨损试验机，对全油膜润滑条件下三体磨粒磨损的特性进行了一些实验研究。     

铜带轧制变形区摩擦润滑状态研究

观察分析了轧制变形区形貌特征,研究了不同方向粗糙度对轧制润滑的影响。在轧制变形区并存边界润滑和流体动压润滑;轧辊与轧制的塑性挤压边界接触是获得高光亮表面的必要条件。轧后轧件表面粗糙度Ｒａ和丰满度Ｋ趋向于满足一定润滑条件的最佳值。     

板带钢冷轧乳化液及润滑效果研究

针对冷轧无间隙原子钢(IF钢),配制了2种不同的乳化液,并将其与国内、国外商品级乳化液的冷轧实验进行对比。实验发现乳化油中基础油的选择对乳化液冷轧润滑效果的影响很大,当基础油含饱和脂肪酸高时乳化液润滑能力好,可以用乳化液皂化值来衡量乳化油冷轧润滑效果的优劣。一般皂化值高的乳化液可用来冷轧屈服强度较高、成形较困难的板带钢。使用乳化液冷轧后的表面形貌明显优于无润滑状态的轧后表面。在乳化液冷轧润滑过程中,当压下率较低时,轧件的表面质量有所改善,总压下率超过90%以后,轧件的表面质量又呈下降趋势。     

斜齿圆柱齿轮的弹流润滑模型及油膜厚度研究

本文研究了斜齿圆柱齿轮的弹流润滑问题。通过分析斜齿圆柱齿轮的啮合原理及特点,提出以有限宽线接触正反圆锥滚子作为其物理模型,导出了正反圆锥滚子线接触下的油膜间隙方程,这一结论已在该问题的弹流润滑数值计算中得到了令人满意的应用。本文开展的工作对斜齿圆柱齿轮的弹流研究提供了一种有效的理论分析方法。     

椭圆接触油膜润滑的牵曵特性研究

针对润滑油高压下的固化、极限剪切应力存在等现象,采用修正的Smith流变模型,推导了椭圆接触区油膜的牵曵系数表达式.分析了各参数对牵曵性能的影响.以牵引式无级变速器某传动比时椭圆接触区内润滑油无自旋运动为例,绘制了油膜牵曵系数关于滑滚率、最大接触应力和润滑油压黏系数的曲线.     

旋滚条件下弹流油膜的试验研究

应用光干涉方法,对旋滚条件下钢球-玻璃盘接触副形成的弹流油膜进行了试验研究.在试验中,通过调节接触副与玻璃盘旋转中心的距离即偏心距来获得不同程度的自旋分量.试验结果表明,纯滚条件下两侧缘处相等的最小油膜厚度由于自旋分量的引入不再相等,较小的最小膜厚具有较大的速度指数.侧缘处最小膜厚的速度指数大于中心膜厚的速度指数.随自旋的增加,油膜形状的非对称性增加,最小油膜厚度减小.随载荷和滚动速度的增加,自旋引起的油膜形状的非对称性增强.     

雾状油膜水滴冷却润滑车削试验研究

油膜水滴是使用冷空气、微量可自然降解油剂和少量水,经复合喷雾法形成可自然分解的、新型绿色切削液.与传统切削液相比,油膜水滴在保护环境,节省资源等方面有很大的优势.通过车削试验,比较和分析不同冷却润滑条件下刀具磨损和已加工表面质量,揭示出雾状油膜水滴绿色切削液的优越性.     

热轧变形区润滑条件与板带钢表面质量关系试验研究

为研究热轧变形区润滑条件与轧后板带钢表面质量关系,对热轧变形区润滑机理进行计算分析,设计一种可移动式热轧工艺润滑装置,用于板带钢热轧工艺润滑试验。研究不同热轧变形区润滑条件对轧后板带钢表面粗糙度、氧化膜断面厚度、钢板酸洗后形貌的影响。结果表明:在热轧变形区内,当轧制速度大于2m/s时,热轧油油滴在变形区的停留时间在0.07s以内,远小于油滴着火延迟时间与油滴燃烧需要的时间之和,油水混合液来不及燃烧便已通过变形区,仍为传统的液态润滑形式;采用工艺润滑与无润滑相比,表面粗糙度降低40%左右,氧化膜厚度减少50%以上。通过3D显微镜进一步对酸洗后钢板表面进行观察分析,可以发现热轧变形区润滑能够明显减少钢板表面缺陷,使板带钢轧后表面轧制纹络清晰,表面质量得到显著改善。     

斜齿圆柱齿轮的弹流润滑模型及油膜厚度研究

本文研究了斜齿圆柱齿轮的弹流润滑问题，通过分析斜齿圆柱齿轮的啮合原理及特点，提出以有限宽线接触正反圆锥滚子作为其特点模型，导出了正反圆锥滚子线接触下的油膜间隙方程，这一结论已在该问题的弹流润滑数值计算中得到了令人满意的应用，本文开展的工作对斜齿圆柱齿轮的弹流研究提供了一种有效的理论分析方法。     

微量油膜附水滴切削液加工对切削力影响的试验研究

为探索研究微量油膜附水滴(OoW)切削液在车削中对切削力的影响,选出较适宜的切削用量,通过正交试验方案,分别研究在干切削和OoW切削两种不同加工方式下,切削速度、进给量和背吃刀量等切削参数对车削45#碳素结构钢时主切削力的影响。经多元线性回归处理,建立切削力经验公式。结果表明:在使用OoW切削液润滑的情况下,主切削力变化范围较大,但采用较高切削速度、较低进给量、较大的背吃刀量时,主切削力较干切削时有明显下降。     

铝材冷轧变形区油膜形成机理及影响因素

通过计算分析与轧制实验，探讨了名材冷轧变形区油膜形成机理及影响因素结果表明：流劝动力学成膜机理主要依赖于润滑剂粘度和轧制速度，特别是润滑剂粘度较氏时，轧制速度必须达到一定值，否则无法形成有效的油膜，而机械夹带作为低粘，低速条件下变形区主要成膜机理，其膜厚度依赖于轧辊与轧件粗糙度和夹带系数ｍ，０．１〈ｍ〈０．５，且随润滑剂粘度提高而增大。     

Analytical Investigation on the Effect of Multigrade Oil in Piston Ring Lubrication

The use of multigrade oil in engine lubrication is being advocated to consumers to minimize viscosity-temperature effect. However, its effect on piston ring-liner contact has not been fully ascertained. In this work, an attempt has been made to evaluate the friction behavior of multigrade oil in piston ring lubrication. The theoretical model developed by the authors predicts thinner oil films as a result of introduction of multigrade oil in the hydrodynamic zone and a larger piston travel distance near the TDC region in the compression-power stroke cycle without any appreciable film thickness. The multigrade oils are known to offer elasticity, and this is also considered in the analysis to evaluate film thickness.     

Experimental Study of the Smoothing Effect of a Ceramic Rolling Element on a Bearing Raceway in Contaminated Lubrication

The effects of steel and ceramic rolling elements on protrusions from the raceway of a bearing were experimentally investigated. Such protrusions, which are normally caused by solid contaminants in the lubricating oil, create stress concentrations and lead to a reduction in the rolling contact fatigue life of the bearing. To compare the over-rolling effects of steel and ceramic rollers, experiments with steel discs with artificial dents on the surfaces were performed using a modified twin-disc machine. The results show that ceramic rollers can reduce the height of the protruded edge of an artificial dent more than steel rollers, which means that they are more effective in smoothing a damaged surface. The stresses at the contact were calculated by finite element analysis based on the deformed profile of the dented surface. The reduction in the stress level due to the smoothing effect of ceramic rollers is greater than that of steel rollers. According to the Lundberg–Palmgren bearing fatigue model, that smoothing ensures a significantly longer rolling contact fatigue life for a bearing. To put the idea into practice, a rolling ball bearing with two of its nine steel balls replaced with silicon nitride balls (referred to as a “partial hybrid bearing”) was run, together with a full steel bearing of the same model, on a bearing tester in a highly contaminated lubrication condition. The results show that the partial hybrid bearing suffers from less damage in terms of wear. The post-experiment examination of the damaged surface of the bearing raceway found that the surface of the partial hybrid bearing was smoother than that of the full steel bearing. This reveals the smoothing effect of the rolling ceramic element on the contaminant-damaged bearing surface.