Experimental study on microelastohydrodynamic lubrication

The effects of surface irregularities on rolling and/or sliding point contact elastohydrodynamic lubrication (EHL) have been surveyed on the basis of direct observations using the due-chromatic optical interferometry technique. A local fluctuation in film thickness caused by surface irregularities depends strongly on shear flow dominating the EHL conjunction and side leakage. The influence of pressure flow has been examined in relation to the local entrapment at asperities due to pure squeeze motion. In reciprocating motion with a small length of the stroke, EHL films are affected not only by surface irregularities but also by air bubbles produced in the previous stroke. The effects of thickener lumps and groove on grease EHL have also been discussed.