The Development of an Experimental Apparatus for testing Hybrid Lubrication in Spherical Bearings: numerical simulation

This investigation is dedicated to the solution of the indirect problem in a spherical pad lubricated under the condition of hydrodynamic regime, with externally pressurized inlets. The work has been motivated by a recent project which involves the development of an infinite ratio Continuously Variable Transmission (CVT) based on the adoption of a train of rotating spheres placed among two toroidal cones. The real feasibility of this system relies on the efficiency of two lubricated spherical pairs. Although the angular velocities are supposed to be relatively high, the spinning balls may be subject to loads which push them against their sockets. For this reason, it is necessary to deeply understand if a hybrid lubrication strategy might be able to avoid direct contacts and cavitation, specially at high loads or during transients with small velocities. The preliminary numerical simulation has pointed out how hydrodynamic lubrication is more effective when the eccentricity has a component perpendicular both to the load and to the rotation axis.