Design of backdoor

                                                                                        Back Door Design

Objective:

          To design the car backdoor outer upper panel, lower panel, inner panel with necessary reinforcement by using the given styling surface.

Software Used: NX Cad

Introduction: 

          The back door is a hinged door/tailgate at the rear of the vehicle. It may be used for loading and unloading cargo, or to get passengers in and out, in case there are seats present at the rear. The back door comprises of certain components which form the back door assembly together.

                                                                                              

Types:

• Top Mounted Door
• Side Mounted Door
• Bottom Mounted Door

Top Mounted Door:

          This type of back doors is used in a station wagon, pickup truck and some of the  sport utility vehicles. Today’s modern cars use top mounted tailgate system which are both powered and gas stay supported.

                                                                                                 

Side Mounted Door:

          As the name signifies side mounted doors are the one which is used in the van type MPVs, SUVs, Pickup truck Vehicles. This type of  door smaller in size and easily accessed.

                                                                                              

Types Of Mechanism Used:

• Gas Stay
• Power Lift

1.Gas Stay System:

                    Gas stay type of mechanism tailgate is an ideal and commonly used mechanism from lower model to luxury model car. The ideal components of tailgate are hinge, gas stay and some rubber beadings for sealing of door.

                                                                                                

2.Power Lift System:

                           Power trunk lid system is another sophisticated way of trunk/liftgate opening mechanism which is automatically open and close of the trunk and release of the latch by the touch of a button. Powered lift system consists of a power latch, anti-pinch switch, PTG assembly, PTG main switch. When the switch is pressed in the compartment or outside the power latch releases the latch and entire backdoor is opened. The anti-pinch Switch is located in order to avoid accidental hand insertion during the door opening and closing.

                                                                                                

Components To Be Designed:

• Outer Upper & Lower Panel (Thickness = 0.75)
• Inner Panel (Thickness = 0.75)
• Hinge Reinforcement RS & LS (Thickness = 1.5)
• Gas Stay Reinforcement RS & LS (Thickness = 1.5)

Outer Upper & Lower Panel:

          The Outer panel of the backdoor is similar to the other BIW components where it is the aesthetic part of vehicle. The coating provided is of multi stage which has the property of scratch resistance, rust prevention and smooth and attractive finishes. The outer panel also has the provisions for the tail, lamp, rear fog lamp, and also has the provision for license plate mountings. Most of the hatchback cars have the provision for wiper motor.

                                                                                    

Inner Panel

          The inner panel is a component which is used to strengthen the door assembly and it is one of the most important part on which all parts are mounted like hinges, glass guide channel, molded trim, latch etc. The possible method is the integration method. In the integration method the part is stamped out of a single blank. This reduces the number pf tools needed the assembly cost and eliminate any fit ability problem.

                                                                                   

Embosses &Reinforcements:

          With the distinctive cross section embosses are created. The embosses are used to increase the strength of the inner panel. While designing the embosses keep that should not be over strengthen the part. So we prefer to design big embosses rather than small embosses. This embosses are used to distribute the forces sideways. The reinforcements also created to strength the inner panel. The reinforcements are created in this assembly are hinge reinforcement RS &LS and gas stay reinforcement RS & LS. The hinge, gas stay and striker embosses also created on inner panel.

                                                                                  

Latch and Striker Trajectory:

          To design the opening and closing trajectory the hinge and latch are positioned based on the hinge axis and trajectory. The circle drawn should be perpendicular to the latch striker to satisfy the condition. Based on the rotation trajectory the hinge axis latch striker and predefined gas stay are correlated for smooth kinematics of door opening and closing.

                                                                                

Hemming Operation:

          Hemming is a technology which is used in automotive sheet metal joining process such as inner and outer panel joining together ( hoods, doors, tailgate, etc.). It is the process of bending and folding the flange oft the outer panel over the inner one. The accuracy of the operation significantly affects the appearance of the cars outer surfaces. The corner relief also provided during the sheet metal bending to avoid tear and deformation of sheets.

                                                                                           

                                                                                    

                                                                                                         Corner Relief

Draft Analysis:

          The draft analysis command enables you to detect if the part you drafted will be easily removed. This type of analysis is performed based on color ranges identifying zones on the analyzed element where the deviation from the draft direction at any point corresponds to specified values. Minimum draft angle of 7° is considered for draft analysis, green color infers on the part that all face along the tooling direction has positive draft angle greater than 7° and passed the analysis.

                                                                       

Conclusion:

          Thus the back door was designed and developed from the given styling surfaces with essential reinforcements and embosses. To satisfy the manufacturing requirements draft analysis also done on the inner panel.