转向螺母多向联动加载成形工艺研究

Multi-direction linkage loading forming process for steering nut

转向螺母是汽车上复杂异形非圆齿形零件,结构形状复杂,需要多个方向产生变形,各部分变形量不同,成形难度大。在分析其结构形状特点和成形难点的基础上,提出了多向联动加载成形工艺。该工艺在成形过程中,各凸模加载顺序、速度、行程根据材料流动和充填情况进行联动控制,控制材料主动向需要的地方流动和填充,进而提高材料充填性和降低成形力。利用有限元软件对该工艺成形过程中的金属流动规律、材料填充状况、应力分布、成形力进行了数值模拟分析。对转向螺母的多向联动加载成形工艺和顺序加载成形工艺进行了对比分析,多向联动加载成形工艺比顺序加载成形工艺成形力降低了28%。对多向联动加载成形工艺进行了成形试验,成形出的转向螺母充填饱满,尺寸符合图纸要求,未出现锻造缺陷,并进行了小批试制。试验结果表明该工艺具有可行性和实用性。

The steering nut is a complex special-shaped non-circular toothed part on the automobile,which has complex structure and shape.It needs to be deformed in multiple directions and the deformation of each part is different,so the forming is difficult.The multi-directional linkage loading forming process for steering nut is proposed,on the basis of analyzing its structural shape characteristics and forming difficulties.In the process of forming,in order to improve the filling property of the material and reduce the forming force,the loading sequence,speed and stroke of each punch are interconnected controlled according to the material flow and filling situation,so as to control the material to actively flow and fill where it is needed.The metal flow law,material filling state,stress distribution and forming force in the forming process were simulated and analyzed by finite element software.The forming force of steering nut under multi-direction linkage loading is reduced by 28%compared with that under sequential loading.The experiment of the multi-direction linkage loading forming process is conducted,the formed steering nut is full filled,the dimensions meet the requirements of the drawing,and no forging defects are found.The small batch of the steering nuts were produced by using experimental dies.The experimental results show that the process is feasible and practical.