Common faults of bearings Rolling bearings are generally manifested in two kinds of faults, one is that the temperature of the bearing installation part is too high, the other is that there is noise in the operation of the bearing.
1. 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 shell of the mechanism by hand, it should be normal to feel no hot hand. Otherwise, it indicates that the bearing temperature is too high.
The bearing temperature is too high for the following reasons: the quality of lubricating oil does not meet the requirements or deterioration, and the viscosity of lubricating oil is too high; Mechanism assembly is too tight (lack of clearance); Bearing assembly is too tight: the bearing seat ring rotates on the shaft or in the shell; Excessive load; Bearing retainer or rolling body fracture, etc.
2, bearing noise
The rolling bearing is allowed to have slight running noise in its work. If the noise is too large or there is abnormal noise or collision, it indicates that the bearing has a fault.
The reasons for the noise of rolling bearings are more complex. One of them is the wear of the inner and outer rings of bearings. Because of this wear and tear, the bearing and the shell, bearing and shaft coordination relationship is destroyed, resulting in the axis deviation from the correct position, in the shaft at high speed movement produces abnormal sound. When the bearing is tired, its surface metal spalling, will also make the radial clearance of the bearing increase and produce abnormal sound. In addition, insufficient bearing lubrication, the formation of dry friction, and bearing breakage will produce abnormal sound. Bearing wear loose, cage loose damage, will also produce abnormal sound
When the rolling bearing is disassembled and inspected, the failure and damage cause of the bearing can be judged according to the damage of the bearing.
1, raceway surface metal spalling
The rolling body of the bearing and the raceway surface of the inner and outer rings are subjected to the action of periodic pulsating load, which produces contact stress with periodic changes. When the number of stress cycles reaches a certain value, fatigue spalling will occur on the working surface of rolling body or inner and outer ring raceway. If the load of the bearing is too large, this fatigue will be aggravated. In addition, improper bearing installation, shaft bending, will also produce raceway peeling phenomenon.
The fatigue spalling of bearing raceway will reduce the accuracy of shaft operation and cause vibration and noise of the mechanism.
2. Bearing burns
The raceway and rolling body of the burned bearing have a tempering color. The causes of burns are generally insufficient lubrication, substandard quality or deterioration of lubricating oil, and too tight bearing assembly, etc.
3. Plastic deformation
The uneven pits on the contact surface between the raceway and the roller of the bearing indicate that the bearing has plastic deformation. 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 large static load or impact load, which generally occurs on the bearing with low speed rotation.
4, bearing ring crack
The reason for the crack in the bearing seat ring may be that the bearing is too tight, the foreign or inner ring of the bearing is loose, the inclusion parts of the bearing are deformed, and the surface of the bearing is poorly processed.
5. Cage cracking
The reason is insufficient lubrication, rolling body broken, seat ring skew and so on.
6. The metal of the cage adheres to the rolling body
Possible cause is that the roller is stuck in the cage or is inadequately lubricated.
7. Severe wear of seat ring raceway
It may be a foreign body falling into the seat ring, insufficient lubricating oil or improper grade of lubricating oil