1. The 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 the bearing chamber of the equipment is touched by hand, it is normal that it does not feel hot, or the working temperature tends to be higher after the bearing runs for a certain period of time. Stable, will not continue to climb, otherwise it indicates that the bearing temperature is too high. However, when the temperature of the bearing chamber reaches above 80°C, the bearing is in a high temperature working state, and it is necessary to cool and dissipate heat or review the working state of the bearing. 2 Bearing noise Noise is a slippery and continuous sound emitted by the rolling elements rolling on the raceway surface when the bearing is running. It is a unique basic sound that occurs in all rolling bearings. If the equipment is loud or has unusual noises or bumps, the bearing is faulty. 3 Bearing burns The inner and outer rings of the bearing, the rolling elements and the cage heat up rapidly during operation until discoloration, softening, deposition and damage. The reasons for burns are generally: 1. Poor lubrication, improper selection of lubricating oil; 2. Excessive bearing load (or excessive preload); 3. Working clearance is too small; 4. Bearing assembly is too tight; 5. Water, foreign matter Intrusion; 6. The accuracy of the shaft and bearing chamber is poor, and the disturbance of the shaft is large. 4 Metal spalling on the bearing surface The rolling elements of the bearing and the raceway surfaces of the inner and outer rings are subjected to periodic pulsating loads, resulting in cyclically varying contact stress. When the number of stress cycles reaches a certain value, fatigue spalling occurs on the rolling elements or the working surfaces of the inner and outer ring raceways. This fatigue is exacerbated if the bearing is overloaded. However, poor bearing installation and shaft bending will also cause the phenomenon of raceway spalling. Fatigue spalling of the bearing raceway will reduce the running accuracy of the shaft, causing vibration and noise in the equipment. 5 Plastic deformation The uneven pits appear on the contact surface between the raceway and the roller of the bearing, indicating that the bearing has plastic deformation. The reason is that under the action of a large static load or impact load, the local stress of the working surface exceeds the yield limit of the material, which generally occurs on bearings rotating at low speeds. 6 Cracks in the outer ring of the bearing The reasons for the cracks in the outer ring of the bearing may be: 1. The bearing is too tight; 2. The outer or inner ring of the bearing is loose; 3. The receiving part of the bearing is deformed, and the surface of the installed bearing is poorly processed, etc. 7 The reasons for the fracture of the cage are: poor lubrication, broken rolling elements, poor installation, improper use, excessive moment load, large impact vibration, excessive rotation speed, rapid acceleration and deceleration, temperature rise, etc. ‍