本文对一辆微型汽车在试车过程中突然发生变速箱二轴花键和万向节叉耳断裂的事故进行了分析。结果表明:万向节叉耳因材质成分不符合技术要求,内部缺陷严重,在外力作用下导致解理脆性断裂;花键轴因装配失误而增大扭矩形成高载荷,产生了典型的疲劳断裂。 In this paper, an accident of a miniature car suddenly occurred gearbox two-axis spline and yoke fracture of the universal joint during the test was analyzed. The results show that the universal fork prongs are not suitable for the technical requirements because of the material composition, the internal defects are serious, leading to cleavage brittle fracture under the external force. The spline shaft increases the torque due to assembly errors to form high loads, resulting in typical fatigue fracture .