轮毂轴承单元轴铆合装配的铆头优化设计

Optimization Design of Rivet Head for Shaft Riveting Assembly of Hub Bearing Unit

针对轮毂轴承单元轴铆合装配工艺的非线性、非稳态特征,提出一种基于代理模型的轴铆合装配工艺优化方法,并用于铆头成形曲面的优化设计.通过拉伸实验、圆环镦粗实验、轴向进给位移及轴向铆接力在线测试、铆头空间轨迹理论推导等确定有限元建模参数;通过比较模拟和测试的轴向铆接力及轮毂轴端铆接后的几何形状确定有限元模型的准确性;基于现有的铆头设计和轴承寿命理论确定铆头成形曲面的参数化方程和优化目标;基于拉丁超立方抽样策略和有限元结果确定轴承内圈的最大径向变形量、轴向预紧力和轮毂轴端对铆头的作用力与铆头成形曲面参数间的支持向量机回归模型;最后对优化结果进行验证.结果表明,优化后的铆头使轮毂轴承的性能指标得到一定提升.

In order to overcome the nonlinearity and instability of the shaft riveting assembly process of wheel hub bearing units,an optimization strategy based on the surrogate model was proposed for the optimization design of the rivet head.In the investigation,first,the finite-element modeling parameters were determined through the tensile test,the ring upsetting test,the on-site axial feeding displacement test,the on-site axial riveting force test and the theoretical derivation about the space trajectory of the rivet head.Next,a comparison between the simulated and the tested results of the axial riveting force and the hub shaft's ultimate deformed shape was made to verify the effectiveness of the proposed finite element model.Then,on the basis of the existing design experiences and the life theory of hub bearing units,the parametric equations and the optimization objective were determined.Moreover,on the basis of the Latin hypercube sampling strategy and the finite element simulation results,a support vector machine regression model,which takes into consideration the maximum radial deformation of inner ring,the axial preload,the acting force between the hub shaft and the rivet head as well as the forming surface parameters of the rivet head,was established.Finally,a verification of the optimization design was performed,with an improved performance of the hub bearing unit being achieved.