热冲压模具压边与定位装置的设计计算

Design and Calculation of Blank Holder and Positioning Device of Hot Stamping Dies

采用有限元方法研究汽车B柱热冲压过程中压边力对成形质量的影响,当大端区压边力在80~120 kN范围内变化(法兰区压边力恒定为50 kN)时,随着压边力的增加,压应变区域所占的面积比值并没有特别明显的变化,即当大端区压边力的值大到能够控制材料从大端向小端移动以后,增大压边力的值对B柱的成形影响不大;当法兰区压边力在40~80 kN范围内变化(大端区压边力恒定为100 kN)时,压应变区域的大小随着法兰区压边力的增大显著降低,但是当法兰区压边力超过70 kN以后,B柱的侧壁出现了明显的破裂;最终确定汽车B柱大端区压边力为100 kN、法兰区压边力为50 kN。随后,采用曲面定位的方式对汽车B柱的定位装置进行设计,依据B柱毛坯的几何特征及其在重力作用下的初始挠曲线,对6个定位桩的高度和位置进行设计计算。

The effect of blank holder force on shaping quality during B pillar hot stamping process is analyzed by means of finite element analysis. When the blank holder force on the large end changes in the range of 80 to 120 kN（ blank holder on the flange area is kept constant at 50 kN）, with the increase of BHF, the compressive strain area ratio does not change significantly. That means that increased blank holder force has no great effect on the shaping of B pillars when the blank holder force on the large end increases enough to move the material from the large end to the small end. When the blank holder force on the flange area changes in the range of 40 to 80 kN（ the blank holder force on the large end is kept constant at 100 kN）,the compressive strain area reduces with the increase of blank holder force on the flange area. But the side wall of B pillars ruptures when the blank holder force excesses 70 kN. Finally, it is determined the blank holder force on the large end of B pillars is 100 kN and on the flange area is 50 kN. The positioning device is designed by the way of curvature positioning. The height and position of six positioning piles are designed and calculated according to the geometric characteristics of B pillars and its initial deflection curve under gravity.