Design of Hybrid Hydrostatic/Hydrodynamic Journal Bearings for Optimum Self-Compensation Under Misaligning External Loads

A method to design hybrid hydrostatic/hydrodynamic journal bearings, with the criterion of optimized self-compensation under misaligning loads, is presented. An analysis considering laminar and turbulent flow of a Newtonian incompressible lubricant between the bearing and a misaligned shaft, with restricted lubricant supply to each recess, is discussed. The mathematical model considers the modified steady state Reynolds lubrication equation, an exact function for the local bearing radial clearance with a misaligned shaft, the continuity integral-differential equations at the recess limits and boundary conditions at the cavitation zone and outer limits. The finite-difference method was used, and a modular computer program was developed. The procedure follows a univariate search to determine the optimum size and position of recesses and therefore obtain the design with the maximum reactive moment under misaligning loads. A validation of the model was obtained comparing the results with experimental and calculated data from literature. Results for a 4+4 LBP hybrid bearing design are presented.