The Research On The Externally Pressurized Air-Lubricated Bearing In Bi-Rotary Milling Head Based On Numerical Simulation

Because of the merit of high rotary and precision, Externally Pressurized Air-Lubricated Bearing is wildly used. Its shortage is little stiffness, and its structural parameter has great effect on its performance. When Externally Pressurized Air-Lubricated Journal Bearing worked at high speed, dynamic pressure effect and inner friction heat are generated, and result in the change of bearing's performance.Researches are done on the thickness of air-film and its corresponding maximal stiffness under different means of section flux and hole diameter for Externally Pressurized Air-Lubricated Bearing of bi-rotary milling head by means of engineering design methods. These data are of great guidance to the later numerical simulation.Method of numerical simulation for air-lubrication of externally pressurized air-lubricated bearing by CFD software FLUENT6.2 is introduced later. Static characteristic of externally pressurized air-lubricated bearing are got by numerical simulation of static air-lubricated bearing, structure parameters of bi-rotary milling head are fixed based the results. By simulating air-lubricated bearing rotating at high speed, we learn the dynamic pressure effect and cases of heat producing by air-friction.In the last of paper, the FEM thermal analysis for bi-rotary milling head is done using ANSYS9.0, its temperature field gained. By the data, we can estimate the thermal deformation of Externally Pressurized Air-Lubricated Journal Bearings in bi-rotary milling head.