Ferrohydrodynamic thrust bearings

Abstract

This paper treats thrust bearings in which the lubricant is a ferroliquid confined by an applied magnetic field to the gap between two plates, one fixed and one mounted on a rotating shaft carrying an axial load. For plates with plane, parallel surfaces, the lubricant extends beyond the edges of the plates and axially along their sides. Since this is undesirable, other plate geometries are considered, for which the ferroliquid is confined to the gap between the plates. Plate surfaces which are considered are cones, paraboloids and frustrums, i.e. plane, parallel surfaces out to some radius and conical, diverging surfaces beyond. Results indicate that paraboloids and frustrums are suitable, but cones are not. FHD thrust bearings with magnetic plates are stiff, i.e. large changes in axial load produce relatively small changes in gap width. With currently available ferroliquids, FHD thrust bearings are limited to relatively small axial loads.