Sliding Bearing Lubricated with Ferromagnetic Fluid

Abstract

To develop a bearing which is used in clean circumstances, such as in vacuum and in a clean room, an experimental thrust bearing test device was constructed. The ferromagnetic fluids selected are colloidal suspensions of ultrafine magnetite particles in a low-vapor-pressure diester and alkylnaphthalene base fluids. The friction and wear tests with ferromagnetic lubrication were carried out with stationary cylindrical specimens constructed of permanent magnets in contact with the flat end of opposing rotating nonmagnetic cylindrical specimens. The following results were obtained: 1. The boundary lubricating effect of a ferromagnetic fluid, retained at the sliding surface by uniform magnetic field, can reduce the frictional force under low-velocity conditions and the wear caused by the mechanical contact between surfaces.2. The hydrodynamic lubricating effect of a ferromagnetic fluid, retained at the step grooves by the magnetic attraction of permanent magnets, can greatly reduce the frictional force under high-velocity conditions.