Effects of slide-roll ratio and lubricant properties on elastohydrodynamiclubrication film thickness and traction

With tribology research aimed at decreasing energy consumption, two factors are inherently in focus: lubricant film thickness and traction. These fact ors are effectively decoupled and depend on lubricant properties which are sometimes contradictory-favourable for one factor and disadvantageous for t he other. The film thickness ought to be maximized to reduce the number of asperities In contact and thus wear, whilst the traction should be minimize d in order to reduce energy losses. In this experimental investigation the tested lubricants were investigated to see whether they possess beneficial properties for forming thick lubricant films under severe operating conditi ons while maintaining low traction forces. This is done by experimentally s tudying the film thickness reduction due to thermal and rheological effects for a fully flooded electrohydrodynamic lubrication (EHL) contact. The bas e oils tested were a naphthenic mineral VG150, a synthetic poly-alpha -olef in VG68 and a synthetic ester VG46. It was found that the synthetic ester m aintained a relatively thicker lubricant film during sliding than the poly- alpha -olefin and mineral oil. The film thickness reduction for the mineral oil was greater than for the poly-alpha -olefin.