本文主要針對落花生收穫機之傳動主軸受力狀況，應力變化及主軸破壞狀況進行分析。由於落花生田高低不平，加上落花生採收過程中之加速、減速及轉彎操作，造成傳動主軸在落花生採收過程中會受到衝擊負荷作用。依據主軸破斷面之SEM照片看出，主軸破壞為扭轉疲勞破壞，因此必須考慮主軸之疲勞壽命。
本研究是利用ANSYS有限元素分析軟體，進行傳動主軸之應力分析及疲勞壽命分析。分析結果發現，由於主軸材料之疲勞強度不足，造成主軸只有一至三個月之使用壽命。為了提高傳動主軸之使用壽命，必須設法提高主軸之疲勞強度才可以。

This article is pointed to the transmission shaft of the peanut harvester, by using the ANSYS software to analyze the loading condition, stress variation and the fracture mode of the shaft. Because of the rugged peanut field, and the acceleration, deceleration and corner operation of the harvester during the peanut harvest process, the transmission shaft was under the impact load. According to the fracture surface observation result by SEM, the damage of the shaft was caused by torsion fatigue fracture, so the fatigue life of shaft must be considered.
In this study, the stress analysis and fatigue life analysis was conducted by ANSYS finite element analysis software. From the analysis results, it could be found that the fatigue strength of the shaft was not sufficient, so the using life of the shaft was only 1 to 3 months. In order to increase the using life of the transmission shaft, the fatigue strength of the shaft must be raised.