An quantitative analysis for unsteady partial-EHL and experimental discussion

本研究的目的是得到一种适用于具有集中接触的动载混合润滑机械元件的分析模型。本文提出了一种新的数值模型，并通过实验验证了该模型的有效性。首先，介绍了一种基于热弹流体混合润滑理论的稳态分析方法。该模型考虑了润滑剂粘弹性的热效应和接触区的热效应。在这一分析中，不仅使用了弹性-流体动力混合润滑(EHML)方程，而且还使用了润滑膜能量方程。给出了压力、温度分布和摩擦系数的计算结果。计算结果与常规EHML计算结果进行了比较，说明TEHML计算的薄膜厚度比常规EHML计算的薄膜厚度要薄。在低滑移比条件下，TEHML计算的摩擦力大于常规计算的摩擦力。其次，以动力学分析为例，计算了凸轮与从动件之间的摩擦和润滑，包括凸轮的运动方程和润滑膜的挤压效应。在此计算中，在凸轮鼻部附近载荷变化较大的位置，流体绝热变化的影响不容忽视，并通过凸轮和从动件摩擦实验验证了计算的正确性。计算结果与实验结果吻合较好。但试验设备(第一类)刚性不够，受自然振动影响，因此研制了第二类设备。

The purpose of this study is to get a useful analysis model for dynamically loaded mixed lubricated machine elements with concentrated contact. In this report, a new numerical model has been developed and some experiments have been done to obtain the prosperity of the model.First, a steady state analysis based on thermal elast-hydrodynamic mixed Lubrication theory (TEHML) is introduced. It considers thermal effects of lubricant visco-elasticity and heat at contact area. In this analysis, not only equations of the elast-hydrodynamic mixed lubrication (EHML) but also energy equations of lubricant film are used. Results of pressure, temperature distribution and friction coefficient are presented. Results of this calculation are compared with those of normal EHML,so film thickness by TEHML calculation is more thin than that by normal EHML calculation. At low slip ratio, friction of TEHML calculation is more large than that of normal calculation. It means thermal calculation for dynamically loaded mixed lubricated machine elements with concentrated contact is important.Second, for example of dynamically analysis, friction and lubrication between cam and follower has been calculated including equations of motion of cam, and squeeze effect for lubricant film. In this calculation, At the point near cam nose where the load significantly changes, the effects of fluid adiabatic change can not be neglected.Cam and follower friction experiments has been done to valid the calculations. Friction of caluclations accord with that of experiments. But the test equipment (type I) was not enough rigid, it was influenced natural vibration, so type II equipment has been developed.