Design of backdoor

                                                                                A report on Backdoor Design 

About Backdoor 

     A backdoor is a part of an automotive body which performs the open and close operation for the passege to place objects or people to enter into the automotive. The motion of open and close can be up and douwn or side wise also, It will be depending upon the nature of the automotive body. The below images shows the actual backdoor in practical.

                                     

                                                   

Image of Backdoor Assembly:

                   

Parts in Backdoor

     A backdoor comprises of more than two parts assembled together by welding, fasteners to make a complete set. The commonly manufactured backdoor comprises of the below listed parts:

• Backdoor innerpanel
• Backdoor outerpanel upper
• Backdoor outerpanel lower
• Hinge reinforccements L.H. and R.H. side
• Gas stay reinforcements L.H. and R.H. side
• Latch reinforcement 

Backdoor innerpanel:

                                    

                                    

     The above two images shows the overview of backdoor innerpanel from both sides. A innerpanel consists of sealing flange, support flange, windshield area. It also contains the mountings for attaching reinforcements, wipermotor and for other trim parts.

Design considerations in innerpanel:

• The sealing flange shoul have a gap of about 12-15 mm from outerpanel.
• The draft angles for all the features should be above 7 degree for steel material.
• The emboss should be of Y or V shape as a result of study from previous experiments for better distribution of the impact forces.
• The cutouts can be given for making the panel lightweight and also considering the center of gravity.
• The cutouts positions should be considered of easy of assembling the tail lights at assembly stage.
• The position of latch and stricker needed to be considered which is an important consideration for the working of backdoor.
• The sharp corners are needed to avoid for reducing the stress concentration.
• The surfaces that created for design should follow within the tooling direction.
• For mastic seal area required extensions are needed to be provided.
• A clearence of about 0.2 mm is to be maintained between the inner and outerpanel after thickening.
• In this design the support flange is taken as a offset of 25 mm but it varies based on actual process.

Backdoor outerpanel upper:

                                          

     The above image shows the outerpanel upper. 

Design considerations in outerpanel upper:

• The surface that got from styling team should be checked for smoothness.
• Necessary blends are to be provided.
• The clearence and relif for hemming process also needed to be taken care.

Backdoor outerpanel lower:

                                     

 The above image shows the outerpanel lower. the design considerations is mostly similar to outerpanel upper.

Reinforcements:

                         

     The blue colour highlighted area shows the reinforcements for the hinge, gas stay, wiper motor and the latch and stricker. The use of reinforcements is mainly to improve the strength.

Draft Analysis:

     Any part that is being manufatured by deepdrawing process sholud be checked, whether the model is passing the draft analysis, from which we can say that the part is of with reliable drawing quality. The below image shows the draft analysis of the backdoor innerpanel.

                             

Manufacturing Process:

     The manufacturing process used commonly is of deepdrawing process.