Abstract: In the bugling-pressing tests of large-size heavy truck axle housing, axle housing tubes were hydro-pressed by preformed tubes with approximate rotary shape, the wall thickness had large reduction in the middle part of tube, and rear cover had crackings. Therefore, the preformed tubes with D-shaped cross-section and the hydroforming process with axial-circumferential feeding were designed. The stress states and characteristics of deformation in axial feeding stage and axial-circumferential feeding stage were analyzed. The conditions of plastic deformation in different areas and the expressions of circumferential stress at typical nodes of the middle cross section were derived. For a axle housing of 10 t heavy truck, the FEA of hydroforming of preformed tube with D-shaped cross-section was carried out, the variation law of normal stress and shear stress in each area and the law of metal flow along the circumferential direction were revealed. The bulging-pressing test of heavy truck axle housing was carried out, the preformed tube with D-shaped cross-section was successfully produced with good forming. Results show that the circumferential distance of metal flow and distribution of wall thickness are consistent with the values of the FEA, and the thinning rate of wall thickness is significantly reduced. After hydro-pressing forming, the wall thickness in middle part of axle housing has increases, and the rear cover is formed with no cracking. Moreover, the weight of the front cover is decreased by 15.64%.

Key words: heavy truck axle housing, hydroforming, bulging-pressing, axial-circumferential feeding, preformed tube

摘要： 在大尺寸重卡桥壳胀压成形试验中，近似回转体预成形管坯充液压制成形后的桥壳管件，中部桥包壁厚减薄率大、后盖存在开裂。为此，设计了D形横截面的预成形管坯及轴向环向补料液压胀形工艺，分析了轴向补料、轴向环向补料阶段的应力状态及变形特征，推导出不同变形区的塑性变形条件以及中间横截面典型特征点环向应力的表达式。针对某载荷10 t重卡桥壳，进行了D形截面管坯液压胀形有限元模拟，揭示了各变形区的正应力、剪应力的变化规律以及金属沿环向的流动规律。进行了重卡桥壳胀压成形生产试验，成功制备出D形截面预成形管坯，成形性良好，金属环向流动量及壁厚分布与模拟结果吻合，壁厚相对减薄率明显降低；充液压制成形后的桥壳管件，中部桥包部分壁厚增加，消除了后盖开裂隐患，而且切除的附件前盖减少15.64%。

关键词: 重卡桥壳, 液压胀形, 胀压成形, 轴向环向补料, 预成形管坯