Publication

To measure oil film thickness in EHD (elastohydrodynamic) contacts, optical interferometry methods have been used for a long time. However, it is difficult to apply them to measurements for practical bearings because visible lights cannot be transmitted through metal bodies. In the previous study, we developed the electrical impedance method and measured the oil film thickness and the breakdown ratio in steel/glass EHD contacts simultaneously. The accuracy of the oil film measurement by the electrical method was confirmed by comparing it with the optical method. In this study, we applied the developed method to steel/steel EHD contacts. The accuracy of film thickness was evaluated by comparing with the Hamrock-Dowson theory. Besides, the validity of breakdown ratio was evaluated by comparing with the friction coefficient measured simultaneously.