A major cause of a surface damage of the contact loading machine components (bearings, gears, cams etc.) is the rolling contact fatigue, Various methods of condition monitoring are used to detect damage of these components or specimens in the industry or during testing in laboratories. In the past decades, the acoustic emission technique has been developed into useful condition monitoring method. This paper is focused on the testing of rolling contact fatigue of the metallic materials using acoustic emission method. The methodology of testing, experimenal test-rig and preliminary results, are presented in this paper. It can be concluded, that acoustic emission technique can be applied for more accurate rolling contact fatique evaluation of material. and Obsahuje seznam literatury
This paper concerns a study of the lubricant film formation and behavior of a point contact under non-steady state conditions. Transient Elastohydrodynamic (EHD) lubrication, where operating parameters such as speed and load vary over time,occurs in many machine elements including cams, gears and roller bearings. Therefore, an attention in last few years was focused on behavior and formation of a lubricant film in Elastohydrodynamic lubricated (EHL) contact under non-steady state conditions. The critical running sequences of EHL contacts include e.g. starting or halting of contact surfaces and also abrupt increases or decreases of surface speed and load. These cases can cause a rupture of a lubricant film and in consequence of this action also damage of contact surfaces. This study is devoted to the experimental research of the behavior of EHD films during reversal of entrainment in reciprocating motion. Moreover influence of surface tecturing on rolling contact fatigue life of rubbing surfaces was also studied. and Obsahuje seznam literatury