Experimental Study of an Abnormal EHL Film with Inlet-dimples

Using optical interferometry, elastohydrodynmic lubrication of films with an inlet-dimple was studied experimentally under ball-on-disc and spherical roller-on-disc contacts. The results show that the dimple only apwithin a limited entrainment speed range, and this speed range was influenced by applied loads, the entrainment direction and the kinematic condition. The occurrence regime of the dimple had a triangular shape in terms of load versus speed. The observed inlet dimple can be tentatively interpreted by limiting shear stress or wall slippage.