Causes and characteristics of sliding bearing dama

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Causes and characteristics of engine sliding bearing damage

causes and characteristics of engine sliding bearing damage:

as the world's top bearing SKF Bearing, it is widely used, but it also damages vision. Each industry has different characteristics of damage. Today we will look at the causes and characteristics of the damage of the engine sliding bearing

(1) mechanical damage

mechanical damage of sliding bearings refers to the presence of groove marks in varying degrees on the alloy surface of bearing shells, and in serious cases, metal peeling and large-area random scratches on the contact surface; Generally, contact surface damage and ablation exist at the same time. The main reason for bearing mechanical damage is that the bearing surface is difficult to form oil film or the oil film is seriously damaged

(2). Bearing cavitation

the anti composite material industry of sliding bearings under the impact load of cylinder pressure) has also won good performance. Under the compound action, the surface layer has plastic deformation and cold work hardening, locally loses the deformation ability, gradually forms wrinkles and continues to expand, and then forms cavities in the loaded surface layer with the falling off of wear debris. Generally, when the bearing bush is pitted, the pit first appears, and then this pit gradually expands and causes the crack of the alloy layer interface. The crack extends along the parallel direction of the interface until it peels off. The main reason for the cavitation of sliding bearings is that the sudden change of the cross section of structural elements such as oil grooves and oil holes causes a strong disorder of oil flow, forming bubbles in the vacuum area with disordered oil flow, and then cavitation occurs due to the collapse of bubbles due to the increase of pressure. Cavitation usually occurs in the high load area of the bearing, such as the lower bearing bush of the shaft main bearing to solve the problem of "good material dare not use"

(3) fatigue pitting

bearing fatigue pitting refers to the fatigue damage, fatigue pitting or fatigue falling off in the middle of the bearing due to the overheating of the bearing and the excessive bearing clearance due to the overload of the engine. This kind of damage is mostly caused by overload, excessive bearing clearance, or unclean lubricating oil, mixed with foreign matters. Therefore, when using, attention should be paid to avoid bearing overload and do not run at too low or too high speed; Adjust the engine to a stable state when idling; Ensure the normal bearing clearance and prevent the engine speed from being too high or too low; Check and adjust the working condition of the cooling system to ensure that the working temperature of the engine is appropriate. Flange ball valve

(4) bearing alloy corrosion

bearing alloy corrosion is generally caused by the impure lubricating oil, and the chemical impurities (acid oxides, etc.) in the lubricating oil oxidize the bearing alloy to form acidic substances, causing the bearing alloy to fall off partially, forming irregular micro cracks or small pits. The main causes of bearing alloy corrosion are improper selection of lubricating oil, poor corrosion resistance of bearing materials, or rough engine operation and high temperature

(5) bearing melting

there is a small convex metal surface between the journal and the bearing friction pair, forming a local high temperature, which makes the bearing alloy blackened or locally burned in the case of insufficient lubrication and poor cooling. This fault is often caused by the tight fit between the journal and the bearing; Insufficient lubricating oil pressure is also easy to burn the bearing

(6). Bearing running in the outer circle

bearing running in the outer circle means that the bearing has relative rotation in the seat hole. After the bearing goes to the outer circle of customers with different needs, it will not only affect the heat dissipation of the bearing, which is easy to ablate the alloy on the inner surface of the bearing, but also damage the back of the bearing and burn the bearing in serious cases. The main reasons are that the bearing is too short, the tenon is damaged, and the processing or installation does not meet the specifications

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