Lubrication state and frictional mechanism in water-lubricated rubber journal bearings

Owing to using the soft material rubber as the frictional material, the tribological properties of water-lubricated rubber bearings are different from those of conventional rigid bearings. A finite element method is employed to compute the static contact behaviors between a rubber bearing and a journal. Then combining with the experimental dynamic frictional properties, the relationship between the contact area and the frictional performance is analyzed by a statistic technique. The contact characteristics between a rubber bearing and a journal help to form a high dynamic fluid pressure and thus a fluid pocket after a long time operation, resulting in a special morphology of mixed lubrication different from that of conventional rigid bearings. However, the fluid film has a little influence on the frictional performance of the rubber bearings. The statistic analysis shows that the frictional performance is determined predominantly by the size of the load-carrying area between the rubber layer and the journal, which is consistent with the frictional mechanism in the boundary lubrication.