Film Thicknesses in Elastohydrodynamic Lubrication of Rollers by Greases

Abstract

The object of this work was to measure the thickness of the films formed by greases under conditions of elastohydrodynamic lubrication. The thicknesses of the films were estimated from measurements of the electrical capacity between two discs. In general, the mineral oils from which the greases were made formed films whose thickness did not vary with time. The films formed by the greases were initially thicker than those formed by the corresponding base oils but, after continuous running, became thinner than the oil films. Evidence is offered that the differences observed between oils and greases are related to the viscoelastic properties of the lubricants.