Theoretical and Experimental Study on Elastohydrodynamic Lubircation by Bingham-Visco-Elastic Fluids for Greases

本项目的目的是建立一种润滑脂的弹性流体动力润滑理论，因为与其他润滑剂(如油)相比，润滑脂在实际应用中更容易使用。本项目假设的润滑脂的流变方程由一个滑块、两个非线性缓冲器和两个非线性弹簧组成。利用上述流变方程推导了滚子轴承等线接触问题的润滑方程。另一方面，对于球轴承等点接触问题，将流变方程推广为张量形式，得到了润滑方程的偏微分方程式。无论润滑膜中润滑脂的应力是否大于屈服应力，即是否存在油芯，这些润滑方程都是不同类型的。通过对轴承的应用和有润滑脂的旋转气缸的实验，阐明了与线接触问题相比，在点接触问题中，铁芯的形成可能是罕见的。

The object of this project is to establish an elastohydrodynamic lubrication theory for greases, because a grease is used in practice due to easy lubrication system as compared with that by other lubricants such as oil.A rheology equation supposed in this project, which consists of one slider and two nonlinear dashpots and two non-linear springs, is investigated experimentally for the grease.Lubrication equations are derived for line contact problems in such as roller bearings employing the rheology equation mentioned above. On the other hand, for point contact problems in such as ball bearings, the rheology equation is extended in tensor form and the partial differential equation of lubrication equation is obtained. These lubrication equations are different types whether the stress of grease in lubricating film is greater than yield stress or not, i.e. core occurs or not.By an application of the lubrication equations to the bearings and experiment for rotating cylinder with lubricating greases, it is clarified that the core formations may be rare case in point contact problems as comared with line contact problems.