THIN-FILM LUBRICATION .1. STUDY ON THE TRANSITION BETWEEN EHL AND THIN-FILM LUBRICATION USING A RELATIVE OPTICAL INTERFERENCE INTENSITY TECHNIQUE

The mechanism of the transition from elastohydrodynamic lubrication (E HL) to thin film lubrication (TFL) has been studied with a technique o f relative optical interference intensity for measuring the film thick ness. The resolution of the instrument could reach 0.5 nm in the verti cal direction and 1.5 mu m in the horizontal direction. The factors in fluencing the measurement precision and the differences between EHL an d TFL are discussed. Film thicknesses with different lubricants, veloc ities, and loads are measured. The experimental data show that the var iation of the film thickness in TFL is not the same as that in EHL. As the rolling speed decreases, a turning point in the film thickness cu rve is found, which distinguishes TFL from EHL. Consequently, a TFL mo del with a fluid layer, an ordered liquid layer, and an adsorbed layer is proposed. Finally, the functions of the layers are discussed in de tail.