1、Bearing temperature too high: During the operation of the mechanism, the area where the bearings are installed is allowed to have a certain temperature. When touching the mechanism housing by hand, it is normal not to feel hot, otherwise it indicates that the bearing temperature is too high.
The reasons for high bearing temperature include: the quality of lubricating oil does not meet the requirements or has deteriorated, and the viscosity of lubricating oil is too high; The assembly of the mechanism is too tight (insufficient clearance); The bearing assembly is too tight; The bearing race rotates on the shaft or inside the housing; Excessive load; Bearing cage or rolling element breakage, etc.
2、Bearing noise: Rolling bearings are allowed to have slight operating noise during operation. If the noise is too loud or there is abnormal noise or impact sound, it indicates that the bearing is faulty.
3、Metal peeling off on the raceway surface: The rolling elements and inner and outer raceway surfaces of the bearing are subjected to periodic pulsating loads, resulting in contact stresses that vary periodically. 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 raceway. If the load on the bearing is too high, it will exacerbate this fatigue. In addition, improper installation of bearings and bending of shafts can also cause peeling of the raceway. The fatigue peeling of the bearing raceway will reduce the operating accuracy of the shaft, causing vibration and noise in the mechanism.
4、 Bearing burn: The burnt bearing has a sparking color on its raceway and rolling elements. The causes of burns are generally insufficient lubrication, poor quality or deterioration of lubricating oil, and tight assembly of bearings.
5、Plastic deformation: Uneven pits appear on the contact surface between the raceway and roller of the bearing, indicating that the bearing has undergone plastic deformation. The reason is that under high static or impact loads, the local stress on the working surface of the bearing exceeds the yield limit of the material, which usually occurs on low-speed rotating bearings.
6、Bearing seat ring cracks: The reasons for bearing seat ring cracks may be due to the tight fit of the bearing, loose outer or inner rings of the bearing, deformation of the bearing's containment components, poor surface processing during bearing installation, etc.
7、Cage fracture: The reason is insufficient lubrication, broken rolling elements, skewed seat rings, etc.