Why are engine sliding bearings damaged
1. Mechanical damage refers to the appearance of groove marks in different degrees on the alloy surface of the bearing bush. In severe cases, metal peeling and large-scale messy scratches occur on the contact surface; under normal circumstances, the contact surface damage and ablation phenomena coexist. The main reason for the mechanical damage of the bearing is that it is difficult to form an oil film on the bearing surface or the oil film is severely damaged.
2. Under the repeated action of cylinder pressure impact load), the surface layer undergoes plastic deformation and cold work hardening, locally loses the deformability, gradually forms lines and continues to expand, and then as the wear debris falls off, forms holes in the loaded surface layer . Generally, when the bearing bush is cavitated, the pit first appears, and then the pit gradually expands and causes the cracking of the interface of the alloy layer. The crack expands along the parallel direction of the interface until it peels off. The main cause of cavitation in sliding bearings is that the oil flow is strongly turbulent due to the sudden change of the cross-section of structural elements such as oil grooves and oil holes, and bubbles are formed in the vacuum area where the oil flow is turbulent. eclipse. Cavitation generally occurs in high load areas of the bearing, such as the lower bearing pad of the crankshaft main bearing.
3. Bearing fatigue pitting means that due to the overloaded work of the engine, the bearing is overheated and the bearing clearance is too large, resulting in fatigue damage, fatigue pitting or fatigue shedding in the middle of the bearing. Most of this damage is caused by overloading, excessive bearing clearance, or dirty lubricating oil and foreign matter mixed in it. Therefore, when using, you should pay attention 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 normal bearing clearance to prevent the engine from being too high or too low; check and adjust the cooling The working conditions of the system ensure that the working temperature of the engine is suitable.
4. The corrosion of the sliding bearing alloy is generally due to the impurity of the lubricating oil. The chemical impurities (acid oxides, etc.) in the lubricating oil oxidize the bearing alloy to form acid substances, which cause the bearing alloy to partially fall off and form irregular tiny cracks. or small pits. The main reasons for bearing alloy corrosion are improper selection of lubricating oil, poor corrosion resistance of bearing materials, or rough engine operation and high temperature.
5. There are tiny raised metal surfaces in direct contact between the journal and the bearing friction pair, resulting in local high temperature. In the case of insufficient lubrication and poor cooling, the bearing alloy will be blackened or partially melted. This fault is often caused by the too tight fit between the journal and the bearing; insufficient lubricating oil pressure can easily burn the bearing. Regular inspection and maintenance of sliding bearings are required.
Specializing in manufacturing sliding bearing series products, the physical production enterprises have reached 150 million sets of production capacity, with one automatic sintering line. Enterprise technology relying on Research Institute and colleges and universities and colleges and universities and colleges and universities, constantly develop self-lubricating bearing products adapted to different working conditions and various mechanical fields. The product performance has reached the level of foreign products of the same kind. The sales of products all over more than 40 countries and regions at home and abroad, and have been recognized by domestic and foreign users. In 2006, the company passed the ISO9001 quality system certification! And there is TUV system certification!