When the ball bearing is disassembled and inspected, the failure of the bearing and the cause of the damage can be determined according to the damage of the bearing.
1. Metal peeling on the raceway surface The rolling elements of the bearing and the raceway surfaces of the inner and outer rings are subject to periodic pulsating loads, resulting in cyclically changing contact stress. When the number of stress cycles reaches a certain value, fatigue spalling occurs on the working surfaces of the rolling elements or the inner and outer ring raceways. If the bearing is overloaded, this fatigue will be exacerbated. In addition, the bearing is not installed properly, the shaft is bent, and the raceway peeling phenomenon will also occur. Fatigue spalling of the bearing raceway will reduce the running accuracy of the shaft, causing the mechanism to vibrate and noise.
2. Bearing burns Burnt bearings have tempered colors on their raceways and rolling elements. The causes of burns are generally insufficient lubrication, the quality of the lubricant does not meet the requirements or deterioration, and the bearing assembly is too tight.
3. Plastic deformation Non-uniform 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 under the action of a large static or impact load on the bearing, the local stress on the working surface exceeds the yield limit of the material. This situation generally occurs on low-speed rotating bearings.
4. Cracks in bearing races Cracks in bearing races may be caused by over-tightening of the bearing fit, looseness of the bearing's foreign or inner ring, deformation of the bearing's containing parts, and poor surface processing of the bearing.