Study On Dynamic Model And Static Characteristic Of CNC Lathe Spindle System With Static Pressure Gas Bearings

Ultra-precision processing technology is a kind of comprehensive processing technology and an important embodiment of national mechanical industry level. It has also become one of the important symbols to measure the national science and technology development level. Ultra-precision processing technology is closely related to aerospace, defense industry and microelectronics etc high-tech industries. The research and development of ultra precision CNC lathe is one of the main research contents of it. Gas bearings developed rapidly in recently years. It's a new type of bearing can operate with high precision, long service life, no pollution and crawling etc. With the industrial application request stricter on high speed and precision processing technology, precision CNC lathe spindle system using gas bearings with higher rotation accuracy, smaller temperature rise will become developing trend in the future.This paper mainly tries to study the innovation reformation of existing CNC lathe spindle system, combing the advantages of the static pressure gas bearings and the precision processing requirements of CNC lathe. It takes advantage of the small feed of CNC lathe with precision processing and the characteristic of load about gas bearings are relatively small but have high rotation accuracy. This paper uses static pressure gas bearings with small feed holes in the CNC lathe spindle bearing to improve the machining accuracy. It discusses and analyzes deeply on the mechanism of gas lubricating and the principle of static pressure gas bearings. It analyzes and studies the static characteristic of static pressure gas bearings by using super relaxation iteration method and proportion segmentation method and discretizes the Reynolds Equation by using the finite element method. It confirms the parameters of static pressure gas bearings with small feed holes used in the CNC lathe. In the meantime, it uses static pressure gas bearings with small feed holes in the supporting of spindle, establishs the gas membrane force model of gas bearings and the dynamic models of static pressure gas bearing spindle rotor and analyze the dynamic theory of the CNC spindle system. Finally, it establishes the three-dimensional physical model of CNC spindle system by Pro/E4.0 and solves the mode of vibration and critical speed through the method of ANSYS Workbench 12.0 FEA with IGES form. In addition, this paper analyzes and discusses the requirements and basic methods about the static pressure gas bearing manufacturing, designs a test bed of static pressure gas bearing spindle rotor to test dynamic characteristic. This paper provides certain theoretical basis to study the dynamic characteristic for CNC lathe spindle system with static pressure gas bearings through theoretical analysis and research.