浅析变速器换档拨叉断裂失效原因及预防措施  

Analysis of the Causes and Preventive Measures of Fracture Failure of Transmission Shift Forks

作　　者：黄华波 Huang Huabo

机构地区：[1]上汽通用五菱汽车股份有限公司,广西柳州市545007

出　　处：《时代汽车》2020年第16期172-174,共3页Auto Time

摘　　要：为确定某汽车变速器换档拨叉断裂原因,对该拨叉进行了断口宏观分析、SEM电镜分析、尺寸及相关性能检测分析、装配铆压工艺调查及CAE受力分析。分析表明:由于拨叉断裂部位过渡圆角过小,在压铸脱模或压装工序容易造成圆角部位应力集中;拨叉断口处存在气缩孔铸造缺陷,降低了拨叉强度,同时拨叉衬套铆压时可能引起的损伤加剧拨叉断裂风险。上述综合因素导致拨叉在使用中受到较大外力时发生断裂,针对上述导致拨叉断裂的风险因素,制定了相应的解决方案。In order to determine the cause of the fracture of the shift fork of an automobile transmission,the article carries out the macroscopic analysis of the fracture,SEM analysis,size and related performance test analysis,assembly riveting process investigation and CAE stress analysis.The analysis shows that:due to the too small transition fillet at the fractured part of the shift fork,stress concentration at the fillet is likely to occur during the die-casting demolding or press-fitting process;there is a gas shrinkage hole casting defect at the fracture of the shift fork,which reduces the strength of the shift fork,and at the same time the shift fork may cause the damage when the bush is riveted and in turn increases the risk of fork fracture.The above-mentioned comprehensive factors cause the shift fork to break when subjected to a large external force during use.For the above risk factors that cause the shift fork to break,corresponding solutions have been formulated.

关 键 词：拨叉 断裂 过渡圆角 应力集中 气缩孔 

分 类 号：U46[机械工程—车辆工程]