Research On Dynamic Pressure Performance Of Micro-Bevel Hydrostatic Thrust Bearing

With the proposal of the "Made in China 2025" plan,hydrostatic support technology is more widely used in heavy-duty CNC equipment,due to its advantages in terms of reliability and machining accuracy.Its core values are also more important,such as in aerospace,shipbuilding and many other fields.However,due to the large size of the support structure and the high line speed under heavy load,it is easy to cause lubrication failure phenomena,such as the oil film is thin and the bearing capacity is insufficient,ultimately affects machining accuracy and operational reliability.Therefore,this paper proposes to design the original hydrostatic bearing oil pad into a micro-bevel type.The wedge shape of the oil pad and the high working speed can form dynamic pressure.This dynamic pressure can compensate the hydrostatic failure of the bearing,which could be used to study the dynamic pressure performance of the micro-bevel hydrostatic thrust bearing.In this paper,firstly,based on hydrodynamics,bearing structure,hydrostatic and dynamic pressure lubrication theory,the mathematical model for theoretical analysis of micro-bevel hydrostatic bearing oil film is established.Using Solidworks and ICEM-CFD three-dimensional software,the bearing geometry model and the high-quality structured mesh model of lubrication wedge oil film are established.Then the wedge parameter of the oil film and its corresponding value range are defined,and the viscosity-temperature equation of No.32 oil is written into the program.By using the FLUENT software,the variable viscosity simulation of different wedge-shaped oil films is carried out under the conditions of seven loads and six higher working speeds,and the influence laws of wedge height variation on oil film bearing pressure,velocity,vorticity,mass flow rate under high speed and heavy load conditions are analyzed.The reason for the hydrostatic failure of the bearing and the optimal wedge parameter range for dynamic pressure compensation are analyzed.Finally,the correctness of theoretical analysis and simulation are verified by designing the experimental scheme to test the actual bearing capacity of the bearing under the conditions of the optimal wedge height.The results show that the hydrostatic failure of this kind of hydrostatic bearing under high speed and heavy load is more obvious.By adopting micro-bevel oil pad with a certain wedge height and using the dynamic pressure effect of the wedge shape and high speed can compensate for the problem of bearing hydrostatic capacity insufficient.Heavy load has less influence on dynamic pressure performance.The variation of the wedge height and the higher working speed has a greater influence on the dynamic pressure performance of the bearing.