Abstract: In order to improve the strength and toughness of the trailer coupler and its connecting parts, the structure of the trailer coupler and the material of the trailer coupler are optimized. Using the finite element software HyperWorks to simulate and verify the trailer coupler under different working conditions, and to analyze the residual deformation of the trailer coupler after unloading. The analysis shows that the residual deformation of the optimized trailer coupler is lower than that of the original one, and the yield strength of the structure of the trailer coupler is improved. The impact toughness of 40CrMo steel for trailer coupler can be increased by heat treatment. The effect of tempering time after quenching on the microstructure and properties of 40CrMo steel is studied, the process of heat treatment is 790 ℃quenching +560 ℃ tempering. The impact toughness of the material increases with the prolongation of tempering holding time.

Key words: Toughness of the trailer coupler; Finite element; Yield strength; Tempering holding time; Impact absorption work

摘要： 针对现役某车辆拖车钩存在强韧性不足导致拖车钩牵引拉脱的问题，通过优化拖车钩 结构和材料两方面增加拖车钩自身及连接部位的强韧性。采用有限元软件 HyperWorks 对拖车 钩施加不同工况载荷进行模拟验证，对载荷卸载后的拖车钩残余变形量进行分析，分析表明， 优化后的拖车钩较原状态的残余变形量降低，拖车钩的屈服强度有所提升，采用热处理方式 可提升拖车钩用 40CrMo 钢材料的冲击韧性。研究了淬火后回火保温时间对 40CrMo 钢组织 性能的影响，试验结果表明，热处理工艺为 790 ℃淬火+560 ℃回火，材料的冲击韧性随着 回火保温时间的延长而提升。

关键词: 拖车钩；有限元；屈服强度；回火保温时间；冲击吸收功