Hydrodynamic Lubrication of the Rib-Roller End Contact of a Tapered Roller Bearing

Abstract

The behavior of the lubricated rib-roller end contact of a tapered roller bearing is studied both theoretically and experimentally. A theoretical hydrodynamic approach was first developed for smooth and rigid surfaces for the particular geometry and kinematic conditions found in this contact. Simultaneous measurements of traction forces and film thicknesses by optical interferometry are performed in a special device made of a flat glass disk and a steel toric specimen which simulates this contact, lubricated with a mineral oil at ambient temperature. Good argeement is noted for both film thickness and traction forces between the hydrodynamic theoretical and experimental results. The experiments which are extended to the elasto-hydrodynamic regime show that central and minimum film thicknesses are lower than the calculated values using classical fully flooded and starved elastohydrodynamic theories. This departure is attributed to side flow effects. Traction curves obtained in this regime, under moderate pressures, show that the oil behavior remains newtonian.