关键词: 伺服电机；电机轴；调质处理；疲劳断裂；应力集中

Abstract: When the servo motor is in service for three months, the motor shaft suddenly breaks. Through the appearance inspection, low power observation, fracture analysis, metallographic analysis, chemical analysis and mechanical property analysis of the motor shaft, the fracture cause is explored. The results show that the fracture mode of the motor shaft is fatigue fracture. The main causes of fatigue fracture are low hardness of the shaft center leading to insufficient strength, surface mesh ferrite structure defect, and too small chamfer of the cutting groove aggravating stress concentration, and poor heat treatment process is the root cause of insufficient strength. At the same time, the corresponding improvement measures are put forward to prevent such incidents from happening again.

Key words: Servo motor; Motor shaft; Tempering treatment; Fatigue fracture; Stress concentration