Research Of Characteristics For Gas Bearing With Spiral Groove

Compared with the traditional bearing,gas bearing’s unique characteristics whichinclude little friction, lower temperature rise, no pollution, high rotary precision, highspeed, less pollution and bad environment available make it widely used in all kinds ofmachinery. At present, the development direction of gas bearing generally towards tohigher speed,higher rigidity, better stability and higher precision.However, when thespeed of specific bearing reach a degree, vortex motion will destabilize the bearingrotation, and this will dead a significant impact to the normal work of the precisionmachinery.In addition, when gas bearing rotates in high speed, there will have obvioushydrodynamic effect.If it can be reasonably used then it will be possible to effectivelyincrease the rotational stiffness and stability of rotor. However, for cylindrical bearingwhich has smooth inner hole and shaft, the hydrodynamic effect to stiffness is relativelylimited. Therefore, according to such a specific problem and the structure of hydrostaticbearing, we try to add a pair of spiral groove on the bearing to improve the stability ofthe gas bearing. So, the main point of this topic will be focused on analysis of thebearing capacity and stability of the gas bearing which has spiral groove.My work willinclude the following points:Analyzeing the static characteristics of the bearing. Establishing finite elementmodel of bearing according to the Reynolds equation and bearing’s boundary conditions.Establishing the calculation program of the carrying capacity and stiffness distributionbase on the weighted residual method.How is parameters of the spiral groove structureinfluences the static characteristics is my priority in this job,and then comparing theresult in different situations.After getting gas bearing’s static characteristics, then analysis its dynamiccharacteristics. Here mainly used method is PH perturbation method. Expanding theReynolds equation in the first order of Taylor, then dynamic stiffness and damping forceof the hydrostatic bearing can be gotten. In the process of calculation, using differencemethod and overrelaxation iteration method to solve the partial differentialequations,and using Simpson complex integral method to get the dynamic characteristiccoefficients.Here we focuse key point on the change of characteristic coefficients whenbearing structure parameter changes,and compare the continuous changes in differentsituations.