152QMI型发动机连杆弯曲、断裂原因分析与受力计算

152QMI型发动机是各型号发动机中连杆最易弯曲、断裂的机型之一。经过分析检查, 引起连杆弯曲变形或断裂的原因是:1)连杆承受巨大压力及一定的弯矩,连杆受弯后,使活塞销通油孔处应力集中,强度下降;2)连杆小头孔中心与连杆小头孔毛坯外圆中心不同心,使一边孔壁变薄,强度下降。

Bending and Fracture of 152QMI Engine Connecting Rod

The 152QMI engine is one of the machine whose connecting rod is the most prone to bending and fracture. Analyses and checking show that the reasons causing the bending and fracture of the connecting rod are as follows: 1) The conn-rod bears too big pressure and certain bending moment; when the rod bends, stress concentrates on the oil vent of the piston pin which causes strength drop; 2) Decentraction of the conn-rod small end hole center with the excircle center of the conn-rod small end hole blank, which causes the hole wall of one side getting thin with the strength dropping.