The Drawing Process Optimization And Die Design Of The Lower Shell Of The Car Battery Box

Automobile has become an indispensable tool in people's daily life.Under the social situation of energy shortage and environmental damage,major automobile manufacturers are actively developing new energy vehicles,and pure electric vehicle is the most important new energy vehicle.In this situation,the battery box of new energy vehicles has become the key component of new energy vehicles.In this paper,a brand of electric vehicle battery box lower shell as the research object.The function and forming characteristics of the part are quite different from those of the traditional automobile stamping parts: the head of the part has a communication front end,and the structure of its side wall is relatively complex,which is prone to wrinkle,crack and other failures;the drawing depth of the part is large,about 115 mm,and the angle between the side wall and the bottom is 90 °,and other materials of the pressing surface are required to supplement the drawing deformation,and the side wall area of the sheet metal After the sheet drawing,it is easy to crack or fail the sheet,so it is more difficult to form than general box drawing parts.In view of this topic,this paper mainly carried out the following research work:1.Combined with the forming structure characteristics,forming defects and cold stamping forming technology of automobile stamping parts,the development status of numerical simulation technology of stamping forming is analyzed;the traditional and modern mold development modes are analyzed and compared,so as to point out the superiority of modern mold development mode.2.The mechanical analysis of the box type parts is carried out.By comparing the box type parts of the similar structure,the mechanical characteristics of the box type parts are obtained,which are uneven stress distribution,uneven deformation distribution and uneven deformation speed,laying the theoretical foundation for the development of the lower shell mold of the battery box of the electric vehicle.The basic theory of the numerical simulation of the metal sheet stamping is systematically analyzed,which is helpful for the battery of the electric vehicle This paper provides technical support for numerical simulation algorithm analysis and numerical simulation of the lower shell of the box,introduces AutoForm software,and focuses on the analysis method of the numerical simulation results,so as to prepare for the next numerical simulation of the lower shell mold of the battery box of the electric vehicle.3.After the process analysis of the lower shell of the battery box,the forming scheme is determined as: drawing,shaping,trimming,positive punching,side punching,among which the drawing process is the focus of this paper.After the parts are pretreated,the digital analog of the parts is imported into AutoForm to set the process parameters.The main process parameters of the first simulation are determined as follows: the material type is dc06,the sheet size is rectangular sheet,the length is 1800 mm,the width is 1250 mm,the blank holder force is1000 MPa,and the friction coefficient is 0.15.After the first simulation,the simulation results are obtained: the front end and side wall of communication parts are cracked,and there are a series of problems in many places,such as excessive thinning,insufficient drawing,compressive stress,material thickening,etc.,so further optimization is needed.4.By using the control variable method,the shape of the sheet metal,the resistance of the drawbead,the blank holder force and the friction coefficient are simulated,and the influence of different factors on the forming quality of the lower shell of the battery box is analyzed.Based on the results of the first simulation and the analysis of the influence factors of different factors on the forming quality of parts,the second,third and fourth simulation,namely the third optimization,is carried out.Before the second simulation,the orthogonal experiment method is used to obtain the optimal combination of factor levels under various factors.The parameters of the scheme are:friction coefficient zero point one two,drawbead coefficient One point five,the blank holder force is 1500 KN,and then the parameters are used to simulate.The conclusion is that although the optimal parameters obtained from the orthogonal test improve the forming quality,the forming quality is still not ideal,and there is excessive thinning and stretching The main problems focus on the front-end area of communication.Based on the simulation results of the second deep drawing process,third simulations were carried out to translate the sheet material to the X axis in order to translate 20 mm,thus reducing the material at the front end of the communication and reducing the resistance.Then third simulations were carried out to conclude that the mobile sheet material played a significant role in reducing the area of the front end of the communication,but there were still many problems such as too much thickening and deep drawing,further optimization is needed.Based on the simulation results of the third deep drawing forming,the fourth simulation is carried out to reduce the blank holder force to 1000 KN,and the simulation results are obtained:the forming quality of the parts is significantly improved,through the adjustment of the part sheet metal movement and the pressure coefficient,the communication front-end sheet metal margin and the pressure coefficient are reduced,thus the resistance is reduced,and the deep drawing cracking is effectively alleviated;and the material flow is effectively improved Conditions,and finally get qualified parts.The optimal process parameters are: friction coefficient is zero point one two,the coefficient of drawbead is One point five,the blank holder force is 1000 KN.5.According to the data provided by the numerical simulation,the drawing die for the lower shell of the battery box is designed and optimized.On this basis,the structural design and optimization of the shaping die,trimming die,punching die and side punching die are completed,and the die is manufactured with the cooperation of the die factory,and the die engineering experiment is carried out with the optimized process scheme simulated,and the produced parts are full Sufficient technical requirements.