Analysis And Experimental Study On Vibration Characteristics Of Aerostatic Bearing

Aerostatic bearings are hydrostatic bearings that use air as the lubricating medium because air is resistant to high temperatures and pollution.Aerostatic bearings are widely used in semiconductor manufacturing,high-precision measurement,and ultra-precision manufacturing.When the traditional scholars studied the aerostatic bearing,the research focused on the static characteristics of the aerostatic bearing.By solving the momentum conservation equation of the gas flow viscous incompressible fluid,the gas flow state in the air hydrostatic bearing is calculated,and an aerostatic bearing that satisfies the functional requirements is designed.With the ever-increasing manufacturing precision of ultra-precision manufacturing equipment,higher requirements have been put forward for aerostatic bearings.When the film thickness is reduced to less than 10 ?m,the thin air effect begins to affect the performance of the hydrostatic bearings.The traditional research method is no longer applicable,and the steady-state vibration inside the gas film also restricts the application prospect of the air hydrostatic bearing.In this paper,the method of impinging jet and molecular dynamics is used to analyze the internal gas flow state of the bearing.Through the numerical simulation and experimental research,the formation mechanism of the internal micro-vibration of the hydrostatic bearing is analyzed,and the influencing law of the factors affecting the micro-vibration is explored,which provides a new idea and theoretical route for the design of the air hydrostatic bearing.The main research contents of this article are as follows:(1)Study aerostatic bearing gas film in the bearing region of the slip characteristics an experimental bench for measuring the hydrostatic bearing is built.By comparing the experimental data with the numerical simulation results,the stiffness of different layers in the film is analyzed,and the applicable range of the ANSYS software is determined.(2)The mechanism of micro-vibration of aerostatic bearing is analyzedBased on the combination of stratification theory and carrying experimental conclusion,the equivalent kinetics model of micro-vibration and gas hammer is deduced and mathematically.Based on the theory of jet mechanics,the cavitation zone of the aerostatic bearing is divided into free jet zone A,stagnation zone B,transition zone C and wall jet area D,and the control equations of different regions are established.By analyzing the flow characteristics and heat transfer characteristics of the gas in the gas chamber,it is determined that the cyclone phenomenon causes micro vibration.(3)The experimental results show that the cyclone is validatedAn innovative air film pressure measuring device for the hydrostatic bearing was built to measure the air pressure inside the film at the micrometer scale.The feasibility of numerical simulation was verified by comparing the numerical simulation data with the experimental results.In the experiment,the existence of the cyclone and the pressure drop at the cyclone were verified through breakthroughs,which proved that the construction of the experimental platform is reasonable and feasible.(4)clear the working parameters and design parameters on the cycloneBased on the combination of experimental data and numerical simulation results,the influence of parameters and working parameters on the cyclone strength and position of the aerostatic bearing structure is analyzed.The mechanism and working parameters of the aerostatic bearing and the parameters of the bearing structure are analyzed.The impact of the relationship.Combined with the vibration test and the frequency response experiment,the influence of cyclone intensity and cyclonic position on the micro-vibration time domain characteristics(vibration intensity)and frequency domain characteristics(natural frequency)is further explored.