Lubrication Characteristics of Double Rectangular Cavity Hydrostatic Bearing at High Speed

Due to the change of working speed (especially high speed) and the heat phenomenon in internal fluid caused by friction, the oil film becomes thinner in the running process of the hydrostatic bearing, which will affect the machining precision and operation reliability. In order to solve this problem, the dynamic mesh technique was used to explore the oil film lubrication characteristics of the hydrostatic bearing at high speed under variable viscosity conditions.The research method was based on the new Q1-205 double rectangular cavity hydrostatic thrust bearing, and the theoretical analysis model of bearing oil film lubrication was established. Using the dynamic mesh method, the C language compiler was used to edit the UDF program for controlling the movement of boundary layer grids and variable viscosity of lubricating oil, the dynamic performance of the bearing under the high rotational speed was simulated and analyzed by finite volume method, its speed included 80, 100, 120, 140, 160, 180 and 200 r/min. The influence laws of oil film thickness variation on oil cavity temperature, oil cavity pressure, fluid velocity and flow under different working speed conditions were revealed. Finally, this study investigated the oil film thickness, oil cavity pressure and temperature under conditions of different working speeds, and verified the theoretical analysis and simulation. It is found that the increase of the temperature of the oil film was accelerated with the decrease of the oil film thickness under the high speed conditions. The reason was that the viscosity of the lubricating oil was reduced at high temperatures, that is the reason for more pressure loss. The dynamic pressure formed was not sufficient to compensate for pressure loss at high speed. As a result, with the increase of working speed, the pressure in the oil cavity was reduced under the thickness of the low oil film.