Effect of the Processing Method on the Microtopography of Rough Layers and on Oil Absorption by Friction Surfaces

The paper presents the results obtained for assessing oil absorption of the microrelief of heavily loaded surface layers. The studies have shown that it is preferable to form a friction surface by means of grinding, since such a surface is characterized by a higher level of oil absorption, which promotes a better involvement of the lubricant. An analytical model has been developed, which makes it possible to determine the thickness of the lubricating layer taking into account the oil absorption level of the contacting surfaces. It should be noted that as the load acting on the contact of the surfaces in a friction assembly increases, the thickness of the lubricating film decreases, and in the range of low load values, the intensity of its changes is more significant than it is in the zone of increased load. It has been shown that increasing velocity from 0.5 to 2.0 m/s leads to an average 2.8-fold increase in the thickness of the lubricating film, whereas changing relative the oil absorption level from 0.4 to 0.6 results in an almost 1.6-fold increase in the thickness of the lubricating film. Thus, the parameter of relative oil absorption by rough contacting surfaces exerts the greatest effect on the change in the thickness of the lubricating film in friction assemblies.