重卡桥壳轴向环向补料液压胀形内压加载路径的确定

Determination on Internal Pressure Loading Path of Hydroforming with Axial-circumferential Feeding for Heavy Truck Axle Housings

轴向环向补料液压胀形变形过程复杂,合理的加载路径确定困难,成形时易发生失稳起皱及胀裂。通过变形分析,揭示了轴向环向补料液压胀形两个阶段各典型位置发生变形所需内压的变化规律,确定了线性增压—恒压—线性降压的加载路径,推导出各阶段的内压计算公式,给出了上控制模平面高度与最大扩径量的关系。针对某载荷10 t重卡桥壳,通过有限元模拟及工程试验验证了加载路径的正确性,揭示出加载路径线性降压段的降压系数、上控制模高度系数对管坯成形质量的影响,确定了二者的合理范围,消除了失稳起皱及开裂的隐患。

The deformation processes of hydroforming with axial-circumferential feeding were complex,and it was difficult to determine a reasonable loading path.The tube was prone to instability wrinkling and cracking in forming.Based on the deformation analysis,the variation laws of internal pressure for the deformation at typical positions in two stages of the hydroforming with axial-circumferential feeding were revealed,the loading path of linear pressurization—constant pressure—linear depressurization were determined,the calculation formula of internal pressure in each stage was derived,and the relationship between the plane height of upper control die and the maximum diameter expansion was given.For an axle housing of 10 t heavy truck,the finite element simulation of hydroforming axial-circumferential feeding and the engineering tests were carried out,and the correctness of loading path was verified.The influences of the depressurization coefficient in the linear depressurization section of the loading path and the height coefficient of the upper control die on the forming quality of the tubes was revealed,and the reasonable ranges of both coefficient were determined.The risk of instability wrinkling and cracking is eliminated.