The Theoretical And Experiment Study Of Hybrid Porous Journal Gas Bearing

Porous gas bearing is an external air supply bearing.It uses new porous material as the bearing surface.The gas penetrates into the bearing surface through a large number of tiny pores inside the porous material.A well-formed lubricating gas film is formed to support the external load.Because of the large air supply area and uniform distribution of pressure field,the porous gas bearing has many advantages such as large bearing capacity,high rigidity,simple structure,good stability and damping characteristics.So it is widely used in precision measuring instrument,machine tool spindle system,inertia test equipment and other fields.At present,there are many basic research literatures on porous gas bearings at home and abroad.But most of the literatures treat porous gas bearings as pure hydrostatic bearings.Most of the authors believe that the bearing and the rotor is almost coaxial,that is,they ignore the role of wedge effect.In the case of high-speed rotation,the dynamic effect of the wedge-shaped space is relatively scarce.The similar experimental research is very few.Therefore,basing on the mass conservation equation,Darcy’s law,NS equation to establish the gas lubrication model,the finite difference method and the Newton-Raphson iteration method are used to study the static characteristics of the porous hydrostatic mixed gas bearing.The dynamic characteristics of the bearing are calculated by using the perturbation method.In addition,the high speed test rigs to carry out the push-pull experiment and the hammer percussion experiment of the porous hydrostatic gas bearing are used in this paper.Theoretical analysis and experimental results show that the dynamic pressure effect on bearing characteristics has a very important role,and that it can significantly improve the bearing static bearing capacity.At the same time,the dynamic pressure effect on the bearing dynamic stiffness and damping characteristics also have a great impact.In the design and practical application of porous gas bearing,it is very important to fully consider the coupling effect of static pressure and dynamic pressure effect.