1. the bearing temperature is too high: in the institution's operation, the installation of the bearing parts allowed to have a specific temperature, When touching the mechanism shell by hand, it should be normal not to feel hot. Otherwise, it indicates that the bearing temperature is too high.

Cause: the quality of lubricating oil does not meet the requirements or deteriorates, and the viscosity of 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 shell; Excessive load; Broken bearing cage or rolling element, etc.

2. Bearing noise: the rolling bearing is allowed to make slight running noise during operation. If the noise is too loud or there is abnormal noise or impact sound, it indicates that the bearing is faulty.

Reason: relatively complex.

① The mating surfaces of the inner and outer rings of the bearing are worn. This kind of wear destroys the matching relationship between the bearing and the shell, the bearing and the shaft, resulting in the deviation of the axis from the correct position, resulting in abnormal noise when the shaft moves at high speed. When the bearing is tired, the metal on its surface will peel off, which will also increase the radial clearance of the bearing and produce abnormal noise.

② Insufficient bearing lubrication, dry friction and bearing breakage will produce abnormal sound.

③ After the bearing is worn and loose, the cage is loose and damaged, which will also produce abnormal noise and damage to the bearing.

During the disassembly and inspection of rolling bearing, the fault and damage cause of bearing can be judged according to the damage of bearing.

3. Metal spalling on the raceway surface: the bearing rolling element and the inner and outer raceway surfaces are subjected to periodic pulsating load, resulting in periodic contact stress. When the number of stress cycles reaches a certain value, fatigue spalling will occur on the working surface of rolling element or inner and outer race raceway. If the load of the bearing is too large, this fatigue will be exacerbated. In addition, improper bearing installation and shaft bending will also produce raceway peeling. The fatigue spalling of bearing raceway will reduce the running accuracy of shaft and cause vibration and noise of mechanism.

4. Bearing burn: there is a return fire color on the raceway and rolling element of the burned bearing.

The causes of burns are generally insufficient lubrication, unqualified or deteriorated lubricating oil quality, and too tight bearing assembly.

5. Plastic deformation: uneven pits appear on the contact surface between the raceway and the roller of the bearing, indicating that the bearing has plastic deformation.

Cause: under the action of large static load or impact load, the local stress on the working surface of the bearing exceeds the yield limit of the material, which generally occurs on the bearing rotating at low speed.

6. Bearing race crack: the crack of bearing race may be caused by too tight bearing fit, loose bearing outer ring or inner ring, deformation of bearing containing parts, poor surface processing of installed bearing, etc.

7. Broken cage: the reason is insufficient lubrication, broken rolling element, seat ring skew, etc.

8. The metal of the cage adheres to the rolling element, which may be due to the rolling element being stuck in the cage or insufficient lubrication.

9. Serious wear of race raceway: foreign matters may fall into the race, insufficient lubricating oil or inappropriate lubricating oil brand.