Externally Pressurized Bearings as Servomechanisms. I—The Simple Thrust Bearing

Abstract

The externally pressurized bearing may be considered and analyzed as an hydraulic closed-loop servomechanism. The use of restrictor feed devices introduces an inner loop that reduces the gain. The time-dependent flow due to the change in volume with film thickness creates a “lead” break frequency favorable to stability. Fluid compressibility, on the other hand, leads to a “lag” break frequency which, if it approaches or becomes less than the “lead” frequency, results in bearing instability. Analysis by transfer function furnishes fresh insight into EP bearing behavior.