An Analytical Study on the Rotational Accuracy of Externally Pressurized Air Journal Bearing

The effect of shape error on the rotational accuracy of an externally pressurized air journal bearing with point sources is analyzed theoretically. The shape errors taken into account are roundness errors of both the journal and bearing, and the roundness profile is assumed to be of a sinusoidal lobe shape. The rotational accuracy is studied by investigating the amplitude of the journal center locus calculated by nonlinear analysis of the Reynolds equation for compressible fluid. The mass unbalance effect on rotational accuracy is not considered in this paper. It is shown that roundness errors, frequency of roundness pfofile, feeding parameter, and load significantly affect the rotational accuracy of an externally pressurized air journal bearing.