Causes of Cage Fracture during Bearing Operation

• Shanghai Zhio Technology Co.,Ltd 
• 2023-08-29

The cage plays a role in isolating the rolling element at an equal distance in the rolling bearing and preventing it from falling, guiding and driving the rolling element to rotate. Generally speaking, the cage of thin-walled bearings with equal cross-section will not be damaged under reasonable working conditions, but incorrect operations in daily production can reduce the service life of the bearing cage. Common failure phenomena of cages include: broken cages, loose or broken rivets, broken cages, and scattered rolling elements. So, what are the reasons for the fracture of equal cross-section thin-walled bearing cages?
1. Insufficient lubrication
During the operation of bearings, if the lubrication work is not done properly, it will affect the normal operation. Therefore, it is necessary to ensure that the lubricating oil is sufficient and sufficient for the use of the bearings. If the lubricating oil is not sufficient, it will cause the thin-walled bearings with equal cross-section to be in a lean oil state, which will easily form bite wear and worsen the working surface condition, As a result, the torn objects that bite and wear will enter the cage, causing abnormal loads on the cage, which may cause the cage to fracture.
2. Abnormal load on the cage
When there are problems with the cage during installation, such as inadequate installation, tilting, excessive interference, etc. It is relatively easy to cause a decrease in clearance, which exacerbates friction and heat generation during use, softens the surface, and causes abnormal peeling too early. As the peeling expands, foreign objects enter the pocket holes of the cage, causing the cage to operate slowly and generate additional loads, exacerbating the wear of the cage. Such a deteriorating cyclic effect may cause the cage to break and be scrapped.
3. Foreign objects have invaded the cage of thin-walled bearings with equal cross-section
In fact, the intuitive reason for the fracture of the cage is because foreign objects enter the cage. Once foreign objects enter, they will affect the operation of the cage, especially some hard foreign objects, which will intensify the wear of the cage and generate abnormal additional loads, which may cause the cage to fracture.
4. Creep phenomenon
Creep phenomenon is also one of the reasons for cage fracture. The so-called creep refers to the sliding phenomenon of the ferrule, which causes the load point to move in the surrounding direction due to sliding when the fit surface interference is insufficient, resulting in the deviation of the ferrule relative to the axis or the shell in the circumferential direction. Once creep occurs, significant wear occurs on the mating surface, and the worn powder may enter the interior of the thin-walled bearing with equal cross-section, resulting in abnormal wear, peeling of the raceway, wear of the cage, and additional loads, which may even cause cage fracture.
5. The quality of the cage is too poor
The quality issue of the cage also affects its use. If the quality is poor, it may break when encountering wear during use, especially when the cage is defective. Common defects include cracks, large non-metallic inclusions, shrinkage holes, bubbles, or riveting defects such as missing nails, cushion nails, or gaps between the two halves of the cage, and serious riveting injuries, These situations are all likely to cause the cage to break.
The above is the analysis and introduction of the reasons for the fracture of the equal cross-section thin-walled bearing retainer. In fact, there are many other reasons that cause the fracture, such as when the bearing vibrates, the inertia force can be large enough to cause fatigue cracks, which can also cause the retainer to fracture over time. If the bearing runs beyond the designed speed of the cage, the inertia inside the cage may also cause the cage to fracture.