Research On Load Performance Of Aerostatic Radial Bearings For High-speed Precision Grinder

Support forms are key factors to ensure the accuracy and load performance of thegrinder spindle. Air lubricated bearings have the advantages of high speed, low friction,high rotating precision and non-polluting, compared with conventional rolling bearingsand liquid-lubricated bearings. Structure parameters and dynamic pressure effect havecritical influence on load carrying capacity of the air bearing.An improved finite difference method(FDM) is used to solve the existingproblems such as poor convergence and low efficiency in the traditional methodadopted to deduce the pressure distribution of air bearings. Solution process for theReynolds equation is presented in detail. Based on the flow balance principle, avariable step size successive approach iterative method is presented to improve thecomputational efficiency and convergence of the algorithm. General programs arewritten to calculate the pressure distribution of aerostatic radial bearing by MATLAB.Besides, the accuracy and convergence of the improved FDM is verified. The impactof the main parameters on the bearing properties is analyzed by orthogonalexperimental method, in addition, the effects of dynamic pressure effect of the airbearing on the bearing load capacity and air consumption are also analyzed using thecomputational fluid dynamics software FLUENT which is based on the finite volumemethod. The results show that the study on aerostatic radial bearing load performanceby using improved FDM is feasible and the algorithm still have fast convergence speedto very thin gas film thickness. The order of the factors which affect the aerostaticradial bearing’s load carrying capacity is as follows: the average clearance, theeccentricity, the orifice diameter, the supply pressure, the bearing length and thenumber of orifice per row. Dynamic pressure effect will have obvious influence on theincreasing of load capacity when the bearing average clearance is smaller.Based on this study, the structural design of the aerostatic radial bearing andhydrostatic composite spindle for high-speed precision grinder is presented, and the bearing’s load capacity is calculated. These results provide basis for the design ofhigh-speed precision grinder.