Abstract: Fretting wear failure of connecting spline between friction plate and inner hub occurred in durability test of a hybrid transmission gear clutch. Based on the fretting wear theory, the key factors affecting the wear amount were found out. Combined with finite element analysis (FEA), the failure problem was repeated, and found the main reasons for the failure were the shaft bending deformation, the outer hub axial deformation and the spline tooth contact stress. After considering the space limitation, suggested to reduce the contact stress as the main scheme. By increasing the number of spline teeth and exchanging the connect spline between friction plate and steel plate, the inner hub spline contact stress could be effectively reduced by 85% in theory, and which was further confirmed by finite element analysis could be reduced by over 75%. The final improvement scheme passed the clutch durability test certification. The results provides some guidance for solving the fretting wear problem in the transmission.

Key words: Hybrid transmission; Gear clutch; Fretting wear; Problem analysis; Durability test

摘要： 某混动变速器挡位离合器在耐久试验过程中出现摩擦片与内毂连接花键微动磨损失效 问题。基于微动磨损理论，找出影响磨损量的关键因素。结合有限元分析（FEA），复现失效 问题，得出轴系弯曲变形、外毂轴向变形、花键齿面接触应力为失效的主要原因。综合考虑 空间限制因素后，从降低齿面接触应力着手，通过增加花键齿数、摩擦片与钢片连接关系互 换等，有效降低理论接触应力达到 85%，并通过有限元仿真进一步确认实际内毂接触应力降 低 75%以上。最终改进方案通过离合器耐久试验认证。研究结果为变速器内出现的微动磨损 问题解决提供了一定的指导。

关键词: 混动变速器；挡位离合器；微动磨损；问题分析；耐久试验