Research On Precision Forming Of Automobile Motor Shell

Drawing is an important method of sheet plastic forming, and the method has a wide range of applications in the manufacturing sector. The drawing process of stepped cylindrical member also has an important role in industrial production. At present, the motor casing of automobile are widely made by casting. This thesis adopts the technique of sheet metal forming, while ensuring the required of product size precision, at the same time,improve the surface quality of products and using performance. This method improve the production efficiency, and has certain economic significance.In this study, the motor casing is a step cylinder, and drawing coefficient is small. In drawing process, the parts can not be annealed to stress treatment. In order to smaller the internal residual stress, which will has an influence on the size of parts, it is needed to allocate each drawing deformation of material. Therefore, to ensure the accuracy of parts,you must adopt reasonable forming process, and make the part after forming internal stress is smaller, the springback is smaller. The accuracy of the components required to reach0.01 mm, so how to ensure product accuracy, and at the same time, improve the stability of the deep drawing process has become the focus and difficulty of the process research.This study is based on the theory of cylindrical pieces drawing, to analysis the distribution of stress and strain in drawing process. In deep drawing process, the blank board apply a stress on the blank to decreases tensile stress made by punch, so as to reduce the dangerous of material thinning. At the same time, it also improves the liquidity of material, and improve the stability of forming process.In the forming process, first of all need to forming large rounded corners without flange cylinder parts, then drawing each step and fine shaping. Five deep drawing finishing process were designed, and allocate each drawing drawing coefficient reasonably. It need to preform ladder round, and then shape it one by one. In the final step in the drawing process, pull the ladder round to the size which is smaller than the required. At the final step, using Counter loop deep to draw this part so that the material stress cancel each other to reduce springback, which make the parts have a good fit to the shape of the mold, thusensuring parts a high-precision.Using dynaform numerical simulation technology,to obtain the blank forming limit diagram,and to judge the rationality and feasibility of forming process. Analysis of the change of wall thickness in drawing process of the blank, to determine the stability of forming process and optimized forming process.In this study, through the combination of theoretical analysis and finite element numerical simulation, to design the reasonable forming process, has the high reliability.The process has been put into actual production, and has good processing stability, brings huge economic benefits to the enterprise, and accumulated valuable experience in the motor shell drawing forming.