The Influence of Lubricant Compressibility on the Performance of the 120 Degree Partial Journal Bearing

Abstract

This paper discusses the characteristics of the 120 deg bearing as the compressibility parameter Λ is increased from 0 to ∞. At low values of Λ and light loads, the gas bearing behaves as an incompressible lubricated bearing. Curves are developed to show under what conditions of bearing loading, film thickness, and speed the partial gas bearing may be treated by the incompressible theory. The compressibility parameter Λ has a considerable effect on the proper selection of the shoe pivot position and bearing clearance ratio for both maximum load capacity and minimum coefficient of friction. It is shown that the bearing clearance ratio and pivot location can vary considerably and still maintain close to optimum conditions at low compressibility numbers. At higher compressibility numbers, the choice of pivot location has a substantial effect on the bearing load capacity and coefficient of friction. Also discussed are the optimum design ranges of the compressibility number Λ.