汽车底盘内半轴断裂分析  

Failure Analysis of Half-Shaft of Car Chassis

作　　者：姜涛[1,2,3] 刘德林[1,2,3] 赵凯[1,2,3] 孔焕平[1,2,3] 

机构地区：[1]北京航空材料研究院,北京100095 [2]航空材料检测与评价北京市重点实验室,北京100095 [3]中航工业失效分析中心,北京100095

出　　处：《失效分析与预防》2014年第6期361-367,共7页Failure Analysis and Prevention

摘　　要：卡车仅行驶数百公里就发生3起内半轴断裂故障。采用断口宏微观分析、金相组织及硬度检查等手段对内半轴断裂性质进行了分析,并借助有限元方法对内半轴断裂过程和原因进行了讨论。结果表明:内半轴首先在花键根部发生了大应力的扭转疲劳开裂,最终沿半轴横向扭转剪切断裂;内半轴反复承受过大扭矩作用是其纵向疲劳开裂的根本原因,花键槽底存在小的加工台阶引起的应力集中,半轴纵向存在大量非金属夹杂物都对疲劳性能不利。通过提高内半轴强度水平和冶金质量,优化底盘设计平衡分配桥间扭矩,以及通过结构优化降低内半轴应力集中水平等综合改进可以避免此类故障。Three half-shafts of a heavy truck fractured after running for hundreds of kilometers. The failure mode and cause were analyzed by macro and micro observation,metallographic examination,hardness testing and finite element simulation. The results showed that the root of the half-shafts firstly presented high stress torsional fatigue cracking and finally torsional overload fracture happened along the semi axis cross direction. Repeated large torque was the fundamental reason for fatigue fracture of half shafts.Stress concentration caused by the machining steps at the bottom of the spline groove and plenty of non-metallic inclusions on longitudinal direction further reduced fatigue resistance. Enhancing strength level and metallurgical quality,optimizing chassis design and spline groove structure should be implemented to avoid such failure.

关 键 词：半轴 扭转疲劳 扭矩 夹杂物 应力集中 

分 类 号：TG157[金属学及工艺—热处理]