Common fault analysis of bearings

Update:04-04-2019
Summary:

It is not uncommon for the bearing to malfunction durin […]

It is not uncommon for the bearing to malfunction during operation, so there is no need to make a fuss. A failure has occurred and it is critical to judge and deal with it. Today we will explain the causes of common bearing failures.

1. Metal peeling on the raceway surface: The rolling elements of the bearing and the raceway surfaces of the inner and outer rings are subjected to periodic pulsating loads, thereby generating cyclically varying contact stresses. When the number of stress cycles reaches a certain value, fatigue peeling occurs on the rolling element or the inner and outer ring raceways. If the bearing load is too large, this fatigue will be exacerbated. In addition, the bearing is not installed correctly, the shaft is bent, and the raceway is peeled off. Fatigue spalling of the bearing races reduces the accuracy of the shaft and causes vibration and noise in the mechanism.

2. The bearing temperature is too high: When the mechanism is running, the part where the bearing is installed is allowed to have a certain temperature. When the body of the mechanism is touched by hand, it should be normal to not feel hot, otherwise the bearing temperature is too high. The reasons for the bearing temperature being too high are: the quality of the lubricating oil does not meet the requirements or deteriorates, the viscosity of the lubricating oil is too high; the assembly of the mechanism is too tight (the gap is insufficient); the bearing assembly is too tight; the bearing race rotates on the shaft or inside the casing; Large; bearing cage or rolling body fragmentation.

3. Plastic deformation: Uneven pits appear on the contact surface between the raceway and the roller of the bearing, indicating that the bearing is plastically deformed. The reason for this is that under 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 speed.

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