What are the common faults of plain bearings?
According to the long-term experience of diesel engine maintenance, it is found that the common forms of the early damage of journal bearing are mechanical damage, bearing pitting, fatigue pitting and corrosion. (1) mechanical sliding bearing mechanical injury refers to different degrees of grooves appear bearing alloy surface, serious when in contact with the surface of the metal strip and a large area of the messy scratch; in general, the contact surface damage and ablation phenomena exist at the same time. The main cause of mechanical damage of bearing is that the bearing surface is difficult to form oil film or oil film is seriously damaged.
(2) bearing cavitation sliding bearing in cylinder pressure under repeated impact load), the surface layer of plastic deformation and local deformation of cold hardening, loss of ability, and gradually form a pattern and continue to expand, and then with the shedding of debris, the loading surface layer forming hole. In general, pitting occurs when pitting occurs, and then the dimple gradually expands and causes cracking of the alloy layer interface. The cracks extend along the parallel direction of the interface until it is peeled off. The main reason for bearing cavitation is caused by sudden change of strong oil flow disorder cross-sectional oil groove and an oil hole structure elements, the formation of bubbles in the vacuum oil flow disorder, then the pressure generated cavitation bubble collapse. Cavitation usually occurs in the high load areas of bearings, such as the lower bush of the crankshaft main bearing.
