Failure modes and countermeasures of rolling bearings - cage fracture


The fracture of cage belongs to accidental abnormal failure mode. The main reasons are as follows.

 

1. Abnormal load of cage

 

If the installation is not in place, tilt, excessive interference and so on, it is easy to reduce the clearance, aggravate the friction and heat generation, soften the surface, and appear abnormal spalling prematurely. With the expansion of peeling, the peeling foreign body enters the cage hole, which leads to the cage running block and produces additional load, which aggravates the wear of the cage. A deterioration of the cycle may cause the cage to break.

 

2. Poor lubrication

 

It mainly refers to the bearing running in a state of poor oil, is easy to form adhesive wear, and make the working surface state deteriorate, the tear produced by adhesive wear is easy to enter the cage, so that the cage produces abnormal load, which may cause the cage to break.

 

3. The invasion of foreign bodies is a common mode of fracture failure of cages.

 

Due to the invasion of external hard foreign bodies, the wear and tear of the cage is aggravated and the abnormal additional load is produced, which may also lead to the fracture of the cage.

 

4. Creep phenomenon is also one of the reasons for the fracture of cage.

 

The so-called creep refers to the sliding phenomenon of the ring, in the case of insufficient interference of the matching surface, the load point moves to the surrounding direction due to sliding, resulting in the deviation of the relative axis of the ring or the position of the shell to the circumferential direction. Once creep occurs, the fit surface is obviously worn, and the wear powder may enter the bearing, forming the process of abnormal wear-raceway peeling-cage wear and additional load, which may cause the cage to break.

 

5. Cage material defect

 

The cracks, large heterometallic inclusions, shrinkage holes, bubbles and riveting defects (lack of nails, gasket or two semi-cage joint gap, serious riveting injury) may cause cage fracture.

 

Taking countermeasures is to strictly control the manufacturing process.