Five points for attention in bearing Operation

Five points for attention in bearing Operation.

I. Mechanical damage.

In severe cases, metal peeling occurs on the surface of contact and a large area of random scratches occur. In general, bearing mechanical damage refers to the appearance of different levels of grooves on the alloy appearance of the bearing. The primary reason for bearing mechanical damage caused by contact surface damage and ablation appearance is that the bearing surface is difficult to form oil film or the oil film is seriously damaged.

Second, bearing cavitation corrosion.

Plastic deformation and cold work hardening occur on the outer surface, and the sliding bearing is under the repeated effect of cylinder pressure impact load. Part of the loss of deformation ability, gradually form a pattern and continue to expand, and then with the fall of debris, the loaded outer surface forms a hole. Usually, when the bearing bush occurs cavitation, the pit first appears, and then the pit gradually expands and leads to the cracking of the interface of the alloy layer, and the crack expands along the parallel direction of the interface until the fall stops. The primary reason for the cavitation erosion of sliding bearings is that the sudden change of the cross section of the layout elements such as oil grooves and oil holes leads to the intense imbalance of oil flow, and the vacuum area of oil flow maladjustment forms bubbles, and then cavitation occurs due to the increase of pressure and the collapse of bubbles. Cavitation usually occurs in the high load area of the bearing, such as the lower bearing of the crankshaft main bearing.

Third, fatigue pitting corrosion.

Due to the overload operation of the engine, bearing fatigue pitting refers to. Make the bearing operation overheated and the bearing space too large, resulting in fatigue damage in the middle of the bearing, fatigue pitting corrosion or fatigue fall. Most of this damage is due to overloading, large bearing space, or unclean lubricating oil and foreign bodies in it. Therefore, attention should be paid to prevent bearing overload operation from working at too low or too high speed; to adjust the engine to a stable condition when idling; to ensure normal bearing space to prevent engine speed from being too high or too low; check and adjust the working status of the cooling system to ensure that the operating temperature of the engine is appropriate.

4. Corrosion of bearing alloys.

The chemical impurities (acid oxides, etc.) in the lubricating oil oxidize the bearing alloy to form an acidic substance, and the bearing alloy corrosion is usually caused by the impurity of the lubricating oil. Cause part of the bearing alloy to fall, forming irregular tiny cracks or small pits. The primary cause of bearing alloy corrosion is improper selection of lubricating oil, poor corrosion resistance of bearing data, rough engine operation and high temperature.

5. Bearing melting.

The components are at high temperature, and there is a slight raised metal surface direct contact between the journal and the bearing conflict pair. Under the condition of short lubrication and poor cooling, the bearing alloy blackens or partially melts. This problem is often caused by the overtightening of the journal and the bearing, and the short pressure of the lubricating oil also briefly burns the bearing.