Oil-film Behaviour of Reciprocating Slider with Circular Profile : Optical Measurement of Oil-film Separation Boundary

Abstract

Various analyses on the hydrodynamic lubrication of the piston ring with a parabolic shaped face have already been carried out by a number of researchers. However, the boundary condition of oil-film pressure which affects the theoretical oil-film behaviour has not been sufficiently studied in their analyses, because it is quite difficult to measure the oil-film thickness and/or the distribution of oil-film pressures accurately. This paper refers to an optical measurement of the oil-film behaviour of a circular faced slider which reciprocates on an optical flat without a tilting motion. Both the squeeze velocity and the separation boundary of the oil-film are simultaneously measured by means of a thin film interferometry, and their relation is compared with the theoretical relations based on various boundary conditions. Consequently, it is recognized that the Reynolds boundary condition is the most conformable of all conditions with the experimental results.