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Common Damage and Failure of Cylindrical Roller Bearings

wallpapers Tech 2020-10-26
Many people know about the use of cylindrical roller bearings, but when using cylindrical roller bearings, they will find that bearing failures and damages are very common. What are the damage forms and common failures of cylindrical roller bearings? The details are as follows:
 
Damage form of cylindrical roller bearing
 
When the cylindrical roller bearing is disassembled and inspected, the fault and the cause of the damage can be judged according to the damage of the bearing.
 
1. The metal peeling off the surface of the raceway
 
The rolling elements of the bearing and the inner and outer ring raceways are all subjected to periodic pulsating loads, resulting in periodic contact stresses. When the number of stress cycles reaches a certain value, fatigue spalling occurs on the working surfaces of the rolling elements or inner and outer ring raceways. If the bearing load is too large, this fatigue will increase. In addition, if the bearing is installed incorrectly and the shaft is bent, the raceway will peel off. Fatigue spalling of the bearing raceway will reduce the running accuracy of the shaft and cause vibration and noise to the mechanism.
 
2. Bearing burns
 
Burnt bearings have tempered colors on raceways and rolling elements. The causes of burns are generally insufficient lubrication, the quality of the lubricating oil does not meet the requirements or deterioration, and the bearing assembly is too tight.
 
3. Plastic deformation
 
The uneven pits on the contact surface between the raceway and the roller of the bearing indicate that the bearing is plastically deformed. The reason is that the local stress on the working surface of the bearing exceeds the yield limit of the material under the action of a large static load or impact load. This situation generally occurs in a bearing that rotates at a low speed.
 
4. Cracks in the bearing race
 
The reason for the cracks in the bearing race may be that the bearing is too tightly fitted, the outer part of the bearing or the inner ring is loose, the bearing housing is deformed, and the surface of the bearing is installed poorly.
 
5. The cage is broken
 
The reasons are insufficient lubrication, broken rolling elements, skewed races, etc.
 
6. The metal of the cage adheres to the rolling elements
 
The possible cause is that the rolling elements are stuck in the cage or insufficient lubrication.
 
7. The raceway of the seat ring is severely worn
 
It may be that foreign matter has fallen into the seat ring, the lubricant is insufficient or the lubricant brand is not suitable.
 
Common reasons for the failures of cylindrical roller bearings
 
Cylindrical roller bearings generally show two kinds of failure phenomena, one is that the temperature of the bearing installation part is too high, and the other is that there is noise during the operation of the bearing.
 
1. The bearing temperature is too high
 
When the mechanism is running, the part where the bearing is installed is allowed to have a certain temperature. When touching the housing of the mechanism by hand, it should be normal to not feel hot, otherwise it indicates that the bearing temperature is too high.
 
The reasons for the excessively high bearing temperature include: the quality of the lubricating oil does not meet the requirements or deterioration, the viscosity of the lubricating oil is too high; the mechanism assembly is too tight (insufficient clearance); the bearing assembly is too tight; the bearing race rotates on the shaft or in the housing; Large; the bearing cage or rolling elements are broken, etc.
 
2. Bearing noise
Cylindrical roller bearings are allowed to have a slight running noise during operation. If the noise is too loud or there is abnormal noise or impact, it indicates that the bearing is faulty.
The reasons for the noise of cylindrical roller bearings are more complicated. One is the wear of the mating surfaces of the inner and outer rings of the bearing. Due to this kind of wear, the matching relationship between the bearing and the housing and the bearing and the shaft is destroyed, causing the axis to deviate from the correct position, and abnormal noise occurs when the shaft is moving at high speed. When the bearing is fatigued, the metal on its surface will peel off, which will also increase the radial clearance of the bearing and produce abnormal noise.
 
In addition, insufficient bearing lubrication, formation of dry friction, and bearing breakage will cause abnormal noise. After the bearing is worn loose, the cage is loose and damaged, and abnormal noise will also be produced.