变速箱拨叉断裂原因分析与改进

The fracture analysis and modification for gearbox shifting fork

针对镶嵌钢件的铝合金拨叉出现的断裂现象,进行CAE有限元分析,并对断裂件的化学成分、金相显微组织进行分析;发现其Fe元素含量超标,条片状β相(Al_9Si_2Fe_2)较多且粗大,有较密集的缩松、气孔和夹杂等缺陷。为了提高拨叉的强度,对拨叉结构尺寸进行了局部修改,并严格控制铝合金原材料成分和熔炼、压铸工艺过程参数。对改进后的拨叉进行相关试验,结果表明,其强度完全能满足使用要求。

For the fracture phenomenon of aluminum alloy fork inlaid steel part,the article perform CAE finite element analysis,And analyze the chemical composition and metallographic microstructure of the fractured forks.The results show that Fe element content exceeds the standard,Strip-likeβphase(Al9Si2Fe2)is more and coarse,Defects such as shrinkage,porosity and inclusions are relatively dense.In order to increase the strength of the fork,the structure dimension is be modified partially,the composition of aluminum alloy and the parameters of smelting and die-casting process are controlled strictly.The test results show that the strength can fully meet the requirements of use.