| With the rapid development of Chinese economy of recent decades,although the automobile industry of our country started comparably late,the it still developed rapidly.Due to the needs of economic development,the status of commercial vehicles is becoming more and more important.Because of the deepening of environmental protection policies and concepts,the commercial vehicle market will be faced with customer's renewing,and the development of commercial vehicles will be strengthened by this opportunity to improve quality and reduce cost.In terms of both time and cost,the cover mold design occupies the majority of the automotive development cycle.Therefore,it is essential to develop a reasonable process plan in order to improve the product efficiency,reduce development costs,and shorten the development cycle of overall vehicle development.The floor assembly has to bear the weight and load of the cab.The floor longitudinal beams have the function of supporting and reducing the vibration of cab.It is an important structure for strengthening the strength of the floor.They are symmetrically distributed along the centerline of the floor.The double-sided brackets of the floor longitudinal beams are also distributed symmetrically on both sides of the cab floor which help to support the floor longitudinal beams,reinforce the floor frame and share a part of the load.In this paper,the left middle bracket and the right middle bracket of the floor longitudinal beam of the light truck cab of Shijun 'F350' project are taken as the research objects.According to the concept of double stamping,common mold stamping forming of two stamping parts is proposed under the consideration of the customer's producing conditions.The biggest difference between common mold stamping and double stamping is that the two stamping parts are independent during the forming process and do not require an intermediate transition surface to join them up.The common mold stamping design can reduce the complexity of design,shorten the mold development cycle,and reduce the development cost of the mold.Firstly,analyzing the performance of the blank material ensure that it can meet the forming requirements,and the forming process plan is determined according to the product structure characteristics and quality requirements.A deep drawing model of numerical simulation is created in the AUTOFORM by determining the punching direction,designing the binder surface and the supplementary surface.The forming limit diagram is a method widely used to measure the forming quality of automobile panels.In this paper,the forming limit curve of DC04 sheet of 1.5mm is obtained by using the Nakajima forming method according to the principle of forming limit curve and the obtaining method.After the forming principle of each forming area in AUTOFORM is analyzed,the forming limit curve obtained by experiment is compared with the one used in AUTOFORM in order to verify the reliability of the FLD used to analyze product formability in AUTOFORM.Then,according to the theoretical value and experience,the process parameters are initially determined,and the forming limit diagram,thinning rate and rebound amount are analyzed after the numerical simulation.According to the forming result,in order to solve the forming defects,the process plan is improved by adding measures such as drawing ribs and the process parameters are gradually optimized.Finally,the die layout diagrams of each process are completed according to the final optimized process parameters in UG.And the mold design and assembly of each process are completed according to the process characteristics,product characteristics and design criteria. |
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