Study On Lubrication Regime Of Space Bearing Lubricated By Lubricating Oil And Rheological Behavior Of Lubricant

Lubrication has an important influence on bearing’s life. Recently our country has launched many spacecrafts. Bearing has been widely used in the satellite system. According to the data: “The jamming of the bearing” which caused by insufficient oil of bearing is one of the main reasons of the failure of the satellite. Lubrication is a key factor on bearing’s failure. The failure of space bearing lubrication is relate to the friction characteristic of contact pairs and the rheological characteristic of the lubricant. Therefore, research on the lubrication regime and the rheological characteristic of the lubricant is very necessary.Firstly the friction test rig which can simulate the actual working conditions of space bearing is improved. The temperature controller is renewed. After improving the test rig will become accurate and stable in the temperature control system.This paper intends to simulate the actual working conditions of the space bearing, the friction forces of a space lubricating oil NO.4129 are measured at various rolling speeds, lubricant inlet temperatures and normal loads on the friction test rig when the oil is in fully flood and starved. Friction characteristic curves when in fully flood and starved are obtained. Meanwhile, analyze the lubrication performance of the lubricant when in these working conditions.This paper studies the rheological parameters of the lubricant based on the EvansJohnson rheological model. The viscosities of the lubricating oil NO.4129 is measured with the low temperature kinematical viscometer and high temperature kinematical viscometer. The viscosity-temperature curves of the oil are obtained and provide the viscosity-temperature formula of this oil based on the Walther model. The results show that the viscosity of the lubricating oil is insensitive to temperature at low temperature. This thesis presents a graphical method to solve the shear modulus of rollers plus lubricant and the shear modulus of the lubricant. The system shear modulus formula of rolling bearing is derived. This paper also provides guidance to calculate the average limiting stress and the Erying stress. The results show that the elastic shear modulus is higher, and the tangential compliances of the rollers are higher when the pressure is higher, lubricant inlet temperature and rolling speed is lower. Equivalent radius has little effect on the shear modulus. The average limiting stress decreases with the increasing of the rolling speed and lubricant inlet temperature.This study provides a theoretical basis for the engineering application of space bearing lubrication, presents some preliminary work such as exploring the applicability and rheological significance of model have done. It makes certain foundation for the further work.