为了对装载机工作装置进行抗疲劳设计和疲劳可靠性评估，在获得 ZL50G 装载机工作装置固定姿态当量外载荷二维载荷谱的基础上，对载荷谱进行了等寿命加速处理，设计疲劳试验台进行加速加载疲劳试验研究，并对工作装置进行了极小子样疲劳可靠性评估。结果表明: 利用加速加载谱加载 35. 88h 可以等效装载机连续作业 495. 67h，实现了工作装置快速疲劳试验的目的; 工作装置试件的实际疲劳寿命的平均值为9132. 20h，疲劳破坏起始于销轴衬套与动臂焊接处，靠近动臂板处的焊趾裂纹源是造成疲劳断裂的主要因素; 基于给定工作寿命和疲劳寿命试验结果的极小子样疲劳可靠性评估，获得了工作装置寿命与可靠度为 3 次多项式的数学关系。

In order to design an anti-fatigue loader working device and evaluate its fatigue reliability，two dimen-sional load spectrum of the fixed attitude equivalent external load of the ZL50G loader was obtained． Loading spec-trum of accelerated fatigue test and the fatigue reliability evaluation of very small samples were carried out． The results show that 35. 88h of acceleration loading spectrum can be equivalent to 495. 67h of continuous operation of loader，and the purpose of fast fatigue test of working device is realized． The average actual fatigue life of the wor-king device is 9132. 20h． The main cause of fatigue fracture is the weld toe crack near the boom plate． Based on the fatigue reliability evaluation of very small samples with given working life and fatigue life test results，the cubic polynomial of the mathematical relationship between the life and reliability of the working device was obtained．