CAJ | 학술논문

目的：汽车发动机曲轴在疲劳实验的过程中，经常会出现非正常疲劳裂纹，裂纹从轴颈末端的油孔槽开始起源，造成曲轴轴颈的扭转强度达不到要求。有必要对汽车发动机曲轴的疲劳性能进行研究。方法通过疲劳、拉伸、金相实验以及疲劳断口SEM手段，对曲轴疲劳试样进行了分析。结果汽车曲轴疲劳实验在循环基数为1×107次下，弯矩的疲劳极限为607．5 Nm；曲轴轴颈的中部所受到的疲劳极限压力为96．7 MPa；该40Cr曲轴断口为典型的韧窝和台阶混合断裂。结论曲轴的钻油孔在轴颈内壁造成的应力集中，比较容易产生缺陷；曲轴轴颈在交变应力的作用下，很容易产生疲劳裂纹并扩展，导致曲轴的早期断裂。
목적：기차발동궤곡축재피로실험적과정중，경상회출현비정상피로렬문，렬문종축경말단적유공조개시기원，조성곡축축경적뉴전강도체불도요구。유필요대기차발동궤곡축적피로성능진행연구。방법통과피로、랍신、금상실험이급피로단구SEM수단，대곡축피로시양진행료분석。결과기차곡축피로실험재순배기수위1×107차하，만구적피로겁한위607．5 Nm；곡축축경적중부소수도적피로겁한압력위96．7 MPa；해40Cr곡축단구위전형적인와화태계혼합단렬。결론곡축적찬유공재축경내벽조성적응력집중，비교용역산생결함；곡축축경재교변응력적작용하，흔용역산생피로렬문병확전，도치곡축적조기단렬。
During fatigue testing of the automobile engine crankshaft, abnormal fatigue cracks often occur.The cracks originate from the oil hole slot at the end of the crankshaft journal, which leads to the unqualified torsional strength of the shaft journal.It is necessary to have a research on the fatigue performance of automobile engine crankshaft.The crankshaft fatigue sample was analyzed by fatigue test, tensile test, OM, and fatigue fracture SEM.The fatigue limit of the lower mo-ment was 607.5 Nm at the circulation base of 1 ×107 times in the fatigue test of automotive crankshaft.The fatigue limit pressure was 96.7 MPa at the middle of crankshaft journal.The fracture of the 40Cr crank was the typical dimple and step mixed fracture.Due to the stress concentration in the inner wall of the shaft journal caused by the drill hole of crankshaft, the defects occurred easily.On the other hand, under alternating stress, fatigue cracks occurred easily in the crankshaft journal and expanded, causing early break of the crankshaft.