Research On The Peformance Characteristics Of Precision Hydrostatic Guideways Considering Surface Topography

As the core supporting component of ultra-precision machine tools,hydrostatic guideways have a crucial influence on the accuracy of parts.With the wide application of complex curved surface parts,the hydrostatic guideways have made breakthroughs in sub-micron and nanometer precision,and the influence of sub-micron and micrometer-level topography errors on the surface of the guideways has become increasingly prominent.In this paper,the surface morphology of the hydrostatic guideways is divided into roughness and waviness,and their impact on the performance characteristics of the guideways is considered separately.The main work is as follows:Taking the average flow model as the roughness model,the average flow equation of the hydrostatic guideway is obtained.And use the fractal geometry to characterize the surface roughness of the hydrostatic guideway,use the fractal parameter to get the correction coefficient in the average flow equation,and explore the influence of the fractal parameter on the pressure flow factor and contact factor.The finite difference method is used to solve the average Reynolds equation,and the results of the CFD simulation of the three-dimensional model of the rail oil film are compared with the results of the finite difference calculation of the rail.The accuracy of the simplified assumptions related to the finite difference program is initially verified.From two aspects of fractal parameters D and G,the effect of surface roughness on the performance characteristics of hydrostatic guideways was explored.The dual Fourier series is used to fit the waviness profile of the hydrostatic guideway surface,and the correctness of the model is verified by comparison with the measured data.The film thickness equation under waviness is revised,and the corresponding Reynolds equation is solved by finite-difference method.From the two aspects of the length and width of the waviness amplitude and wavelength,the rule of theinfluence of the waviness surface on the performance characteristics of the hydrostatic guideways is explored.A new type of hydrostatic bearing performance test system is designed to measure the support characteristic parameters of hydrostatic bearing parts under different oil film thicknesses under step loading,and the numerical calculation results and considerations of the guideway with surface roughness under the same working conditions the numerical calculation results of the guideways of the waviness surface are relatively compared,and it is found that all the performance indicators have the same trend and the error is within a reasonable range,so as to verify the accuracy of the two calculation methods.Through the above research,the influence rules of the surface roughness and the waviness on the performance characteristics of the hydrostatic guideways are obtained,and the accuracy of the two research methods is verified,which provides certain theoretical basis to improve the movement precision and performance characteristics of the precision hydrostatic guideways.