Study on Change of the Constituent Components of Lubricants in a Conjunction Region under Hydrodynamic Lubrication

摘要

Lubricants are generally composed of many components. The composition of an oil introduced into a conjunction region is not always the same as that of the supplied one. The change in oil composition in a conjunction region, especially in an inlet zone, was studied in sliding contact using cone-plate, cylinder-plate, and ball-plate sliding testers. Lubricants tested were two kinds of poly-a-olefin with narrow-ranged molecular weight distribution different in molecular weights, and mixtures with wide-ranged molecular weight distribution. The constituent components of the lubricants were estimated by Fourier transform-infrared spectroscopic analysis. In a line contact, the oil composition hardly changed in the inlet zone. In contrast, under point contact conditions, for the oils with narrow-ranged molecular weight distribution the compositions were little changed, but with the lubricant of wide ranged molecular weight distribution the composition was changed. The lower molecular weight or lower viscosity components were prone to pass through preferentially in the conjunction region.