Numerical Simulation On The Effect Of Sufficient And Deficient Lubricant State On Performance Of Hydrostatic Bearing

With the rapid development of advanced manufacturing technologies, processingequipment demands higher and higher performance on hydrostatic bearing, especially forhigh-speed cutting equipment. The performance of hydrostatic bearing, which is the key partof heavy process machine, directly affects the efficiency and precision of machiningequipments. The main problem of domestic high-speed heavy-duty CNC lathe is low speedand poor machining accuracy. How to improve the processing efficiency and accuracy is thekey way to raise the world competition. While, the processing accuracy and efficiency ofheavy process machine is decided by theory, design, assembly and other factors. In thecontemporary domestic sphere, the design on heavy static bearing is still in analogies designstage without independent intellectual property rights on optimal design and key technologies.Oil film is the key part in the research on hydrostatic bearing. Until then, the studies of oilflow, pressure distribution and restrictor have been done in greater depths. However, oilleakage groove, which is the key part of hydrostatic bearing, is the main part for the influxand efflux of lubricant. Oil will go back to the oil gathering when the oil leakage groove isdeep. on the other hand, the oil will be full of groove. The oil will return to the hydrostaticbearing for the working platform, which will affect the performance of hydrostatic.In this paper, research findings about load capacity and oil temperature rise of heavyhydrostatic bearing are summarized. On this basis, focusing on the influence of oil states(sufficient and deficient state) on of heavy hydrostatic bearing with constant-flow andmulti-rectangle recess, research on heavy hydrostatic bearing is conducted systematically,which mainly involves the following items,Firstly, establish the relationship between pressure and flow between two fixed parallelplanes, the relationship between pressure and flow in two parallel planes with relative velocity,the relationship between pressure and flow with rectangle oil pad, the relationship betweenpressure and flow with annular gap, the relationship between pressure and flow with stage oilpad in centrifugal effect. Based on above mentioned formulas, the structure of sector oil padis simplified and mathematical modeled. Deduce the carrying capacity of hydrostatic bearingaffected by structure of the oil chamber (effective load area), spinal velocity and oil filmdepth. Secondly, in order to improve the accuracy and credibility of this simulation experiment,CFD theory, including finite difference method, finite element method and finite volumemethod, is summarized with application background and convergence of each method.Control equations and mathematical expressions in CFD are presented in this paper, which aremass conservation equation, momentum conservation equation and energy conservationequation. Combined with this experiment and a large amount of successful examples,universal steps in CFD are proposed, which stresses the importance of control equation.At last, taking heavy hydrostatic bearing with constant flow and multi-rectangle recess inDVT500as research object, geometric modeling and meshing of two oil states are completed,and FLUENT6.3is used to compute the temperature and pressure field distribution atdifferent rotational speed with fruitful results.The affection of oil states on heavy hydrostatic bearing is revealed by comparingperformances data. The role of oil leakage slot structure in the performance of the hydrostaticbearing is proved, which will supply the theory basis for the improvement of oil leakage slotand performance enhance of hydrostatic bearing.