How to determine whether the bearing can be reused？
During regular maintenance of equipment, operation inspection, and replacement of peripheral parts, judge whether the disassembled bearing can be reused is very important. We should carefully investigate and record the appearance of the bearing. In order to find out and investigate the residual amount of lubricant, clean the bearings carefully.
To make sure whether the disassembled bearing can be used again, first, check the status of the raceway surface, rolling surface, and mating surface, as well as the wear status of the cage for any damage and abnormal conditions.
Second, consider the degree of bearing damage, machine performance, operating conditions, inspection period before deciding whether the bearing can be reused or replaced. If the bearing is found to be damaged or abnormal, find out the cause and take countermeasures.
If there are any of the following defects, the bearing can no longer be used and a new one is needed.
1) Any of the inner and outer rings, rolling bodies, and cages with cracks or fragments.
2) Any one of the inner and outer rings and rolling body is stripped.
3) The raceway surface, side block, and rolling body are obviously jammed.
4) The cage is badly worn or the rivets are loose.
5) The raceway surface and rolling body are rusted or scarred.
6) There are significant indentations and scratches on the rolling surface and rolling body.
7) The inner diameter surface of the inner ring or the outer ring has crept on its outer diameter.
8) It changes color badly in overheating.
9) The seal ring and dust cover of the grease seal bearing is badly damaged.
Check the rolling sound, vibration, temperature, and lubrication status of the bearing during operation. The specific conditions are as follows:
The rolling sound of the bearing
The sound detector is used to check the rolling sound and sound quality of the bearing in operation. Even if the bearing is slightly damaged such as peeling, abnormal sound, and irregular sound will be emitted, which can be distinguished by the sound detector.
Vibration of bearing
Bearing vibration is very sensitive to bearing damage, such as spalling, indentation, corrosion, crack, wear and so on will be reflected in the bearing vibration measurement, so, through the use of a special bearing vibration measuring device (frequency analyzer, etc.) can be measured the size of the vibration, through the frequency of the specific circumstances of the abnormal. The measured value varies with the use condition of the bearing or the installation position of the sensor, so it is necessary to analyze and compare the measured value of each machine before determining the judgment standard.
Usually, the temperature of the bearing starts to rise slowly with the operation and reaches a stable state 1-2 hours later. The normal temperature of the bearing varies with the heat capacity, heat dissipation, speed, and load of the machine. If the lubrication and installation parts are appropriate, the bearing temperature will rise sharply and abnormally high temperatures will occur. At this time, the operation must be stopped and necessary preventive measures should be taken. The use of a heat sensor can monitor the working temperature of the bearing at any time, and realize the automatic alarm or stop when the temperature exceeds the specified value, to prevent shaft accidents.