Optimal Design And Experimental Research Of Gas Squeeze Film Bearing Structure Based On Piezoelectric Drive

In recent years,such as high speed ultra-precision machining,lithography machine research and development,micro/nano manufacturing and other advanced technical fields have put forward higher requirements for the performance of bearings,the traditional contact bearings and gas lubrication bearings have been difficult to meet the requirements.Gas extruded film suspension technology based on piezoelectric drive is a new type of non-contact support technology,which overcomes the limitations of traditional support methods and becomes a new research direction in the field of gas lubrication technology.In this paper,a piezoelectric radial inclusion gas extruded film bearing is designed,which is mainly composed of a piezoelectric plate and a metal thin-walled cylinder.An axial rib plate and a circular rib plate are arranged outside the bearing cylinder.The rib plate and the rib plate divide the whole cylinder shell into three vibration regions,and the structure realizes the uniform radial support of the shaft rotor.The radial fully inclusive film lubrication space is formed between the shaft and the bearing,so that the bearing has a higher suspension stability.Based on the theories of plate and shell dynamics and elastic mechanics,a mathematical model of the natural frequency and deflection of the bearing cylinder structure was established,which was taken as the objective function of structural optimization.The size of the bearing structure was optimized by using the multi-objective genetic algorithm,and the optimal size of the bearing was determined.Orthogonal experiments were designed,and the results of bearing structure optimization were simulated and verified by harmonic response analysis and modal analysis in ANSYS.The resonant frequency,radial maximum amplitude and mode shape of the optimized bearing structure were obtained.According to the theory of viscous fluid lubrication,the Reynolds equation of gas extrusion film was derived,and the numerical solution of the equation was obtained by using the alternating implicit difference method.In order to verify the reliability of the numerical method in this paper,the alternating implicit difference method and the finite element simulation method are used to calculate and compare the same gas film example.The results show that the alternating implicit difference method is basically consistent with the gas film bearing capacity calculated by the finite element software.Then the numerical solution method in this paper is used to study the bearing capacity characteristics of the gas extruded film bearing,the influence of amplitude and frequency on the extruded film bearing capacity is analyzed,and the formation reason of the extruded film bearing capacity and the mechanism of cut-off frequency are analyzed.Finally,a prototype of gas extruded film bearing was made and an experimental test system for resonance frequency and radial amplitude of gas extruded film bearing was designed.In order to accurately measure the bearing capacity,a force test platform was set up.The fitting amplitude function of sampling points and the measured film thickness were used as calculation parameters for theoretical calculation of the bearing capacity,and compared with the experimental values of the bearing capacity,the reasons for the errors were analyzed.The experiment proves the rationality of structural design optimization of gas extruded film bearing and the reliability of calculation method.