关键词: 螺旋弹簧, 冷绕成形, 回弹, 数值分析

Abstract: The various parameters in the cold coiling process of helical springs produce great effect on the springback of the springs.Through the analysis of cold coiling and springback processes of helical springs，the finite element computing models of that are established by employing the large non-linear finite element analytical software ABAQUS 6.8.The influences of different values of tensile force，different ratios of the mandrel diameter to the spring wire diameter，and different pitches in the forming process，to the springback respectively and the displacement changes of each node in the medium diameter after the springback are calculated.The simulation analysis shows that the values of tensile force have an important effect on the springback.The larger the values of tensile force，the smaller the springback are.In the condition，the stress of the spring wire is more stable and larger，with the greater proportion of the plastic region in the cross-section of that.For the spring wire with a certain diameter，the larger the mandrel diameter，that is，the greater the ratio of the mandrel diameter to the spring wire diameter，the larger the springback is.When the mandrel diameter is certain，the smaller the spring wire diameter，the fewer the amounts of springback are，with greater stress in the cross-section.On the other hand，when the forming pitch is greater，the stress of spring wire is more instable and the average stress is smaller，with the larger and more instable springback.The medium diameter and pitch of spring increase evidently after the springback，and the stress of spring decreases gradually from the joint of chuck in the springback process.

Key words: helical springs, cold coiling, springback, numerical analysis