发动机球铁曲轴扭转疲劳强度的试验研究

Torsion Fatigue Strength Test for Nodular Cast Iron Crankshaft of Engine

通过某六缸柴油机曲轴的单拐扭转疲劳试验,考察了结构和表面处理工艺对球铁曲轴扭转疲劳强度的影响。结果表明,当连杆轴颈的空心度不大于0.49时,轴颈空心对曲轴的扭转疲劳强度无明显影响;油孔出口结构设计不当将严重损害曲轴的扭转承载能力,它可使零件扭转疲劳极限下降的幅度达30%;表面感应淬火显著降低曲轴的扭转疲劳强度,而离子氮化的作用不明显。

The effects of structure and surface treatment process on the torsion fatigue strength of nodular cast iron crankshaft were investigated by one-throw torsion fatigue test of crankshaft in six-cylinder diesel engine.It is shown that when the hollowness of comnecting rod journal is less than0.49there is no obviously effect of journal hollowness on crankshaft torsion fatigue strength;unreasonable oil-hole design will result in the decrease of load-bearing capacity of crankshaft,especially torsion fatigue strength limit can be decreased30%;surface induction quenching can remarkably reduce the torsion fatigue strength of crankshaft,while ion nitriding has no obvious effect on it.