Design And Research On Performance Of High Stiffness Aerostatic Bearing Of Multiple-microhole

With the further development of modern industry and the continuous upgrading of the industry,the demand for precision and ultra-precision machining continues to expand,and the status of ultra-precision equipment in the manufacturing industry is becoming more and more essential.As one of the vital parts of ultra-precision equipment,aerostatic bearings are extensively used in the field of ultra-precision equipment owing to their advantages of low friction,high running accuracy,no temperature rise,and no pollution.However,due to the compressibility of gas,the bearing capacity and stiffness of aerostatic bearings are low,and their application and development are limited.The constantly upgrading industry requires high stiffness aerostatic bearings.Aiming at the shortcomings of aerostatic bearings,this thesis designed a high stiffness aerostatic bearing with microhole,and further improved the performance of rectangular aerostatic bearings by optimizing bearing parameters.The main research contents of this thesis are as follows:（1）Designed the multiple-microhole aerostatic bearing and conducted theoretical analysis on it.Firstly,Comparing the advantages and disadvantages of different restrictors,a new type of multiple-microhole aerostatic bearing was designed by adopting the microhole restrictor;then combined with the working principle of the multiple-microhole aerostatic bearing,based on the equation of motion,the equation of state,and the continuity equation,the derivation of the gas-lubricated Reynolds equation was introduced,which was used as the theoretical basis for the analysis of the characteristics of the multiple-microhole aerostatic bearing.（2）Simulated and analyzed the static characteristics of the aerostatic bearing to optimize the structural parameters of the aerostatic bearing.Using FLUENT to compare the difference of static characteristics between the multiple-microhole and the traditional restrictor aerostatic bearing,the results showed that the bearing capacity of the multiple-microhole aerostatic bearing was equivalent to that of the simple orifice aerostatic bearing,the stiffness was higher.The capacity and stiffness of the microhole aerostatic bearing were better than that of the annular orifice aerostatic bearing.The influence of microhole parameters such as microhole diameters,numbers,depths,and microhole distribution circle diameters on the static characteristics of the aerostatic bearing were analyzed by simulation,and each microhole parameter was optimized and determined,and a higher static stiffness of the aerostatic bearing was obtained.（3）The simulation analysis of the dynamic characteristics of the microhole aerostatic bearing was carried out.According to dynamic Reynolds equation,a small disturbance analysis model was established.Based on the Dynamic Mesh technology of FLUENT,a UDF was written to analyze the effects of parameters such as diameters of microhole,numbers of microhole,depths of microhole,and diameters of microhole distribution circle on the dynamic stiffness and damping coefficient of microhole aerostatic bearings.（4）Experiments were carried out on the static characteristics and micro-vibration of the self-developed microhole aerostatic bearing.A special processing technology was developed for the designed microhole restrictor,and a multiple-microhole aerostatic bearing was successfully developed.A special experimental platform was designed to test the capacity,stiffness,micro-vibration,etc.of the aerostatic bearing.It was verified that the microhole aerostatic bearing had high bearing capacity and static stiffness.