When the pellet mill roller bearing is disassembled for inspection, the bearing failure and damage cause can be determined based on the bearing damage.
1. Metal peeling on the raceway surface
The pellet machine rolling elements and the inner and outer ring raceway surfaces of the bearing are subjected to periodic pulsating loads, thereby generating periodic contact stress. When the number of stress cycles reaches a certain value, fatigue peeling occurs on the rolling elements or the inner and outer ring raceway working surfaces. If the load on the bearing is too large, this fatigue will be aggravated. In addition, improper installation of the bearing and bending of the shaft will also cause raceway peeling.
Fatigue peeling of the bearing raceway will reduce the running accuracy of the shaft and cause vibration and noise in the mechanism.
2. Bearing burns
The raceways and rolling elements of the burned bearings have tempering colors. The causes of burns are generally insufficient lubrication, the quality of the lubricating oil does not meet the requirements or deterioration, and the bearing is assembled too tightly.
3. 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. The reason is that the local stress on the working surface of the bearing exceeds the yield limit of the material under the action of a large static load or impact load. This situation generally occurs on bearings rotating at low speeds.
4. Cracks in the bearing race
The causes of cracks in the bearing race may be too tight fitting of the bearing, loose outer or inner ring of the bearing, deformation of the bearing's containing parts, poor surface processing of the installed bearing, etc.
5. Cage fragmentation
The reasons are insufficient lubrication, broken rolling elements, skewed races, etc.
6. The metal of the cage adheres to the rolling element
The possible reasons are that the rolling element is stuck in the cage or insufficient lubrication.
7. Severe wear of the raceway
It may be that foreign matter falls into the race, insufficient lubricating oil or inappropriate lubricating oil grade.
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