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Analysis of the main cause of the engine "burning the axle"

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[Abstract]:
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The main reasons for the engine "burning the axle" are:

(1) The manufacturing quality of the crankshaft is poor. The surface roughness of the journal is poor, and the accuracy of the cylindricity is low. In particular, the crankshaft surface of the crankshaft that has been ground during overhaul has a large error in the journal surface. The surface of the journal and the bearing bush are not well fitted after installation, and the contact surface is too small to form an oil film. , causing dry friction.

(2) The manufacturing quality of the bearing bush is poor. The alloy material is poor, the alloy material is loose, and the surface roughness of the bearing pad is too poor to form an effective lubricating oil film between the shaft and the bearing bush.

(3) The bearing cover is deformed, and there is a gap on the back side of the bearing bush. The alloy and the bearing bush cannot be completely tightly fitted and loosened, and the oil passage is blocked, so that the oil supply is interrupted and the dry friction is caused.

(4) The bearing bush is not installed correctly, the gap is not properly adjusted, and the contact area is too large or too small, which makes it difficult to form a lubricating oil film on the contact surface between the shaft and the bearing bush.

(5) The torque of the forbidden bolt of the bearing bush is too small or the bolt loosening measures fail, and the bearing bush is loose, causing the gap between the shaft and the bearing bush to change, thereby affecting the lubrication.

(6) The oil pump is seriously worn or the oil pump suction port filter is clogged, the oil supply pressure is low, and the oil is difficult to supply to the specified lubrication part, resulting in dry friction of the bearing bush.

(7) The oil passage is plugged with impurities, so that the oil to the crankshaft is blocked, causing the shaft and the bearing bush to dry.

(8) The oil pipeline is damaged, the pressure of the oil circulation supply system drops, and the oil is difficult to reach the specified lubrication part, causing dry friction.

(9) When the cooling is started in winter, the throttle is slammed, and the oil is not pumped to the bearing bush under the low temperature and viscous state, and the surface of the bearing pad has been instantaneously heated, causing the metals to melt together.

(10) The engine is seriously overloaded, and there are long-term low-speed and high-torque conditions. Because of the low engine speed, the pump speed is also low, and the oil supply is insufficient, which causes the high temperature between the shaft and the bearing bush to cause the “burning and digging shaft”.

(11) The amount of oil in the engine oil sump is too small, and the bearing bush is not effectively lubricated to form dry friction.

(12) The cooling water penetrates into the oil due to the damage of the cylinder head gasket and the oil radiator. The oil is emulsified and deteriorated, the viscosity is reduced or completely lost, and the surface of the shaft and the bearing bush cannot form an effective lubricating oil film, resulting in more serious dry friction.

(13) The fuel system is faulty. The fuel atomization is not good, the combustion is incomplete or non-combustion, so that the fuel flows into the oil sump along the cylinder wall and dilutes the lubricating oil, resulting in a significant decrease in viscosity, which also causes the "burning tile to hold the shaft".

(14) In the severe winter season, the use of oil with excessive viscosity and excessive freezing point, or the inadequate addition of some additives containing oil and viscosity to the engine oil may cause the oil to flow too slowly in the oil passage, and cannot be pumped in time. It is sent to the bearing bush, causing dry friction between the shaft and the bearing bush.

(15) Use inferior oil to make the journal not effectively lubricated.