Manufacturing Errors Effects on Disturbing Torque of Aerostatic Bearings

In order to improve the drifting accuracy of aerostatic bearings, the manufacturing errors effects on disturbing torque of aerostatic bearings is studied by using the finite element method. The finite element mathematic model of the major influence factors of disturbing torque is established. Then, the finite element equation in the gas film domain is solved and the disturbing torque in the presence of disturbing factors is calculated. The research focuses on elliptical error and prismatic error of journal and incline error of throttle slit. The setting angle of journal, incline position angle of throttle slit and radial eccentricity ratio which affect the disturbing torque is also studied. The results show that roundness error of journal and incline error of throttle slit affect the disturbing torque significantly, that is the greater roundness error of journal and incline error of throttle slit the greater disturbing torque. Disturbing torque is periodic function of setting angle of journal and incline position angle of throttle slit. Radial eccentricity ratio affects the disturbing torque, and there is specific radial eccentricity ratio makes disturbing torque to be extreme point or zero point. In the research, the theoretical disturbing torque value is compared with the experimental value of a certain aerostatic bearing, find that they are on the whole accordant with each other and then prove that the finite element model and the method use to solve the problem is correct. The research is of great significance for designing, manufacturing and assembling aerostatic bearings and for performance prediction of aerostatic bearings.