1. Bearing temperature is too high
When the equipment is running, the part where the bearing is installed is allowed to have a certain working temperature. When you touch the bearing room of the equipment with your hand, it is generally normal if it does not feel hot, or the working temperature of the bearing tends to be stable after a certain period of operation and will not continue to rise. Otherwise, it indicates that the bearing temperature is too high. However, when the temperature of the bearing room reaches above 80℃, the bearing is in a high-temperature working state and needs to be cooled or the working state of the bearing needs to be reviewed.
Noise is a slippery and continuous sound produced by the rolling elements rolling on the raceway surface when the bearing is running. It is a unique basic sound that all rolling bearings will produce. If the equipment makes too much noise or has abnormal noise or knocking sound, it indicates that the bearing is faulty.
The inner and outer rings, rolling elements and retainers of the bearings heat up rapidly during operation until they change color, soften, melt and break. The causes of burns are generally:
1. Poor lubrication and improper lubricant selection;
2. The bearing load is too large (or the preload is too large);
3. The working clearance is too small;
4. The bearing is too tight;
5. Water or foreign matter intrusion;
6. The accuracy of the shaft and bearing chamber is poor, and the shaft disturbance is large.
4. Metal peeling off the bearing surface
The rolling elements and the inner and outer ring raceways of the bearing are subjected to periodic pulsating loads, which generates periodic contact stress. When the number of stress cycles reaches a certain value, fatigue spalling occurs on the rolling elements or the inner and outer ring raceway working surfaces. If the load on the bearing is too large, this fatigue will be aggravated. However, poor bearing installation and shaft bending can also cause raceway spalling. Fatigue spalling of the bearing raceway will reduce the operating accuracy of the shaft and cause vibration and noise in the equipment.
5 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. This situation usually occurs in bearings rotating at low speed.
6. Cracks in the outer ring of the bearing
The causes of cracks in the bearing outer ring may be:
1. The bearing is too tight;
2. The outer ring or inner ring of the bearing is loose;
3. The bearing housing is deformed, the surface of the bearing is poorly processed, etc.
The reasons include: poor lubrication, rolling element breakage, poor installation, improper use, excessive torque load, large impact vibration, excessive speed, rapid acceleration and deceleration, temperature rise, etc.
