slide bearing-Damage in the form of damage in the form of sliding bearing
Plain bearings islide bearingn the engine is usually divided into two types: a liner - thin wall bearing， the shape of tiles， commonly known as bush； another bush， also known as copper sets， the shape of a hollow cylinder。 Lining tile thin wall bearing for supporting the engine crankshaft and connecting rod； bush is mainly used for supporting the camshaft journal and piston pin。 Here we mainly know about is lining tile thin-walled bearings (bearing) in thePlastic bearing form of early damage and preventive measures。
An early damage in the form of
Bearing during normal use， until the final loss of the ability to work， the end of its life， this natural damage is unavoidable due to the gradual wear and tear。 But if due to improper adjustment of the engine assembly lubricant quality is not good or bad conditions of use and other factors resulting in premature bearing wear or a variety of injuries， the early damage caused by human activity。 Early damage not only greatly reduce the life of the bearings， but also affect the normal work of the engine。
Experience of long-term maintenance of the diesel engine found early damage of sliding bearings common form of mechanical damage， bearing cavitation， fatigue pitting， corrosion， etc。。
(1) mechanical damage sliding bearing mechanical damage to the bearing of the alloy surface with varying degrees of grooves， serious in contact with the surface of metal stripping and the emergence of a large area of clutter scratch； under normal circumstances， the contact surface damage and ablation phenomena the same time。 The main reason for bearing mechanical damage to the bearing surface is difficult to form the film or film has been severely damaged。
(2) bearing cavitation sliding bearings in the cylinder pressure shock load) repeated under the surface layer of plastic deformation and cold work hardening， partial loss of deformability， and gradually form the pattern and continues to expand， and then with the debris shedding， produced by the surface layer to form a hole。 General bearing cavitation appears first pit， and then the pit gradually expand and cause cracking of the alloy layer interface， the crack along the interface parallel to the direction of extension until peeling。 The sliding bearing cavitation mainly due to the sudden change in cross-section of structural elements such as grooves and hole caused by the strong disorder of the oil flow and the formation of air bubbles in the vacuum region of the oil flow disorders， then the pressure increases， the bubbles collapse and produce hole eclipse。 Cavitation generally occurs in the high-load region of the bearing， such as the lower bearing of the crankshaft main bearings。
(3) bearing fatigue point of fatigue pitting eclipse refers to the engine work overload， overheating and bearing of the bearing operating clearance is too large， resulting in bearing Central fatigue damage， fatigue pitting or fatigue loss。 This damage is mostly caused by overloading of the bearing clearance is too large， or lubricant dirty， within a mixture of foreign matter due to Therefore， the use should be noted that the bearings to avoid overloading of the work， not too low or too high speed operation； to the engine to adjust the idle speed to a steady state； to ensure the normal bearing clearance， to prevent the engine speed is too high or too low； check and adjust the cooling the work of the system， appropriate to ensure that the engine operating temperature。
(4) bearing alloy corrosion of the bearing alloy corrosion in general district lubricants impure chemical impurity of lubricating oil in Taiwan (acid oxides) bearing alloy oxidation generates acid， causing bearing alloy part off， and the formation of irregular tiny hole or small pit。 Bearing alloy corrosion mainly due to the improper selection of lubricants， bearing materials resistant to the poor corrosion， or engine work brutal temperature。
(5) bearing Shaorong journal and bearing friction pair between the tiny protruding metal surface in direct contact， the formation of localized high temperatures， insufficient lubrication， cooling adverse circumstances， so that the bearing alloy black or local Shaorong。 This failure is often the journal and bearing with tight due； lubricating oil pressure is insufficient to make bearings burned。
(6) bearing go cylindrical bearings go cylindrical bearing here the hole relative rotation。 The bearings go cylindrical， not only affects the bearing cooling， easy to make the bearing inner surface of the alloy ablation， but also bearing on the back injury， and in severe burned bearing。 The main reason is that is too short bearing， Tenon damage， processing or installation does not meet specifications。 |
