Study On The Performance Of Hydrostatic Bearing Oil Clearance By Bearing Shell-Main Shaft Deformation

The research subject of the dissertation stems from the “research on working principle of the new type throttling governor for high performance journal bearing” supported by National Natural Science Foundation of China under the project No. 51075409.Because of the hydrostatic spindle has high bearing capacity, stiffness, machining accuracy, so it is used in precision machine tools widely. But in the process of the practical work of hydrostatic spindle, the temperature of lubricating oil film friction is raised serious especially the spindle speed is higher. The lubricating oil film temperature and oil cavity pressure can make bearing and spindle deform. It will change the radius clearance, which is an important parameters that will affect the performance of hydrostatic spindle. So the temperature of lubricating oil film,the pressure of oil film bearing and the deformation of bearing and spindle will affect its radius clearance. It is vital significance to improve the machining precision of ultra precision machine tool.In this paper, the liquid oil film bearing of main shaft and bearing is the research object. First of all, elaborates the mechanism of oil film bearing lubrication. The oil film bearing clearance function of distribution is derived under ideal conditions with no machining tolerance. Then in the condition of considering the deformations of bearing and the spindle, the function of the radius of the gap calculating model is seted up.Secondly the related theories of the mechanism of temperature rising, thermal transmission of lubricating oil is explained in this paper, as relevant thermal transmission boundary conditions in the process of calculation. At the same time, consider the lubricating oil viscosity-temperature characteristics in the calculation models and its implementation is discussed, which laid the foundation for the subsequent research work.Then, with the hydrostatic fluid mechanics software FLUENT, the finite element models of the spindle are solved. Get the liquid oil film bearing's oil film temperature and pressure field distribution and analysis the distribution of temperature and stress field law. Coupling simulation by ANSYS Workbench, establish the fluid- structure coupling model of liquid oil film bearing, spindle with the oil film. Analysis the shaft and bearing's compound deformations. Analysis the deformations' affect on the temperature and stress field. Then extract the radial deformation of the associated part of the characteristics of geometric and calculate the radius of the new gap comparing with the radius gap of the original models.Analysis results indicate that the oil film bearing and the main shaft deformation have effect on the radius clearance. And the influence should not be neglected, especially in the case of speed of shaft is higher. Besides the lubricating oil viscosity-temperature has great effect on the deformation.