Analysis and treatment of unstable vibration problem of single-stage axial flow fan

This paper analyzed an irregular and unstable vibration issue in a single-stage axial flow fan at a factory. After multiple investigations, the root cause was identified as the main shaft diameter and the bearing inner ring being in a “critical” state of sometimes loose fit causing relative movement and sometimes relative static. When relative movement occurs, the two components rub against each other, causing local heating of the main shaft and thermal bending, resulting in a significant increase in vibration. By applying arc spraying repair to the shaft diameter and strictly controlling the repair and assembly processes, the problem was completely resolved. The rolling bearing looseness fault identification method proposed in this paper can be used for equipment condition monitoring and can bring significant energy savings and economic benefits.