Common Causes of Motor Bearing Failure and Control Measures

As one of the important components of a motor, the performance of the bearing directly affects the normal operation of the locomotive. When the bearing is broken, damaged, sintered, etc., it can seriously impact the driving safety of the locomotive. Therefore, the motor bearing is very important for the locomotive.

1. Common Causes of Motor Bearing Failure
1.1 Quality Problems of the Bearing Itself
The bearing may have problems before unpacking and assembly, such as loose rivets on the cage, cage deformation, bumps, scratches on the rollers or raceways, or even rust. Since newly manufactured bearings are subject to random inspection, individual defective bearings may still be treated as qualified products. Once installed and used, these defects will inevitably trigger bearing alarms.

1.2 Improper Assembly Causing Bearing Damage
During motor bearing assembly, a hydraulic press is generally used to press the outer ring of the bearing into the bearing chamber. If the pressure is uneven during pressing, it can easily cause deformation or damage to the outer ring. Bearings should not be installed into the bearing chamber by knocking. When assembling the inner and outer ring rollers, any misalignment can easily cause axial scratches on the rollers and raceway surfaces, leading to alarms during operation.

According to disassembly and inspection:

There are equilateral triangle-shaped bumps on the edge of the inner ring raceway surface, caused by collisions between the roller and the inner ring raceway during assembly.

There are obvious circumferential scratches on the inner ring, caused by foreign matter entering the bearing.

1.3 Influence of Cleanliness
1.3.1 Grease Cleanliness
Bearings have very high requirements for grease cleanliness. If lubricating oil mixed with quartz sand, iron filings, or other particles is used, it can cause permanent bearing damage during operation, severely affecting performance.

1.3.2 Cleanliness of Parts and Components
Parts related to bearings, including bearing caps, oil guide pipes, and end cap bearing chambers, must be thoroughly cleaned. If not, impurities can be introduced during assembly, affecting bearing performance.

1.3.3 Assembly Environment
During bearing assembly, if there is a lot of floating dust in the environment, it may enter the bearing chamber or mix into the bearing grease, also leading to bearing failure.

1.4 Current Corrosion
After bearing assembly, due to external factors, an unknown current may flow through the bearings during use, producing electrical burn marks on the bearing raceway surfaces and rollers, affecting service life.
There are generally two types of current corrosion:

One occurs when, after locomotive assembly, an incorrect return ground wire overlap position during electric welding causes the bearing to become energized, leading to electrocorrosion.

The other occurs when the motor itself generates leakage current during operation or in the event of a motor explosion, causing current to flow through the bearings and lead to electrocorrosion.

1.5 Operation and Maintenance
When the locomotive is used by the section, it may not receive normal and effective maintenance. Problems include failure to refuel regularly and quantitatively, failure to control the cleanliness and quantity of refueling, inconsistent grease types, and oil leakage from the bearings.