Design of backdoor

                                        Design of backdoor

INTRODUCTION:

The trunk (North American English) or boot (British English) of a car is the vehicle's main storage or cargo compartment, often a hatch at the vehicle. It is also called a tailgate. These doors can be operated manually or electric powered. In most of the luxury cars door is electically operated. It involves a very major role during rear crash cases. So our design must be obey crash requirements. the institute of highway saftey analyse the diffrent accidents and they set a test to rate our car. So these rating depends upon the design of the trunk and material used, flenges, embosses, type of joining of inner panel and outer panel etc.

Types of the back door

Top-Mounted:

This type of back doors is used in a station wagan, pickup truck and some of the sport utility vehicles. Today's modern cars use top-mounted tailgating systems which are both powered and also gas stay supported. These top mounted tailgates provide greater rear vsibility compared to side-mounted or bar doors which have center pillars in it.

Side Mounted Doors:

As the name signifies side-mounted doors are the one which is used in the van type MPVs, SUVs, pickup truck vehicles. These side-mounted doors or barn doors are a lot easier compared to top-mounted doors. These doors are generally smaller in size and can be easily accessed.

Types of mechanisms for Rear Door:

Gas stays:

Gas stay types backdoor/liftgate/tailgate is an ideal and most commonly used tailgate mechanism fron lower segment car to luxury car segment. The ideal components of tailgate consist of a hinge, door, gas stay and some rubber beadings for sealing of door.

Powered lift sysytem:

Power trunk lid system is another sophisticated way of trunk/liftgate opening mechanism which is to automatically open and close of the trunk/liftgate and release of the latch by the touch of a button.

Components to create:

1. Outer Upper Panel
2. Outer Lower Panel
3. Inner Panel
4. Gas Stay Reinforcement
5. Hinge Reinforcement
6. Wiper Reinforcement

Procedure:

  Class A Surface:

backdoor outer upper and lower class a surface has to be repaired according to the smoothness. After repairing the surfaces, the door is divided into two parts as Door Outer Upper and Door Lower Panel.

 First, we need to create the Tooling direction for the Deep drawing operation. It shows that all the operations like embossing is done by considering this vector direction and it will help in manufacturing the part,

Then we will be creating the Back door inner panel flange by offsetting the outer surface at a distance considering the sheet thickness and thickening direction.

Then created the connecting flange to join the inner panel and sealing flange.

Then for the windshield panel mounting, windshield panel is created and joined with sealing flange.

  Now to assemble the back door with the vehicle Hinges are used to open and close the door. For that to increase the local area strength we have to design the emboss and provide the appropriate reinforcements to withstand the load acting upon it.

GAS STAY REINFORCEMENT:

 Gas Stay is a device used for supporting the back door in its open position. Gas stay requires no manpower and is engaged into support position automatically as the back door opens. One end of the Gas Stay is fixed on the backdoor and the other end on the Body Side or on the Back door stationary area.

            Embossing is provided at the Gas Stay mounting area to compensate for weakness and improve strength.

LATCH  AND STRIKER REINFORCEMENT:

•  The Latch and Striker emboss were designed by creating a trajectory that follows the opening and closing of the back door with respect to the hinge axis.
• The position of the hinge should be perpendicular to the latch when the latch and striker meets. The circle is drawn from the center of the hinge axis to find the path of the striker and positioned perpendicular to the path

BACK DOOR OUTER PANEL 

 The Outer Panel is the styling surface of the back door. Other components of the backdoor are designed with reference to the outer panel. It acts as the outer cover and deals with the aesthetics of the car.

In this design outer panel is divided into two parts

1. Outer Upper Panel
2. Outer Lower Panel

OUTER UPPER PANEL:

          The Outer Upper Panel Extracted from a styling surface.and did changes according to our reqirement .

          The thickness provided for the outer panel is 0.75 mm

          Hemming is provided with the corner relief.

OUTER lower Panel :

          The Outer lower Panel Extracted from a styling surface. and did changes according to our reqirement .

          The thickness provided for the outer panel is 0.75 mm

          Hemming is provided 

HEMMING AND RELIEF:

HEMMING:

•  Hemming and seaming are two similar metalworking processes in which a sheet metal edge is rolled over onto itself.      Hemming is the process in which the edge is rolled flush to itself.
• The outer panel was designed as two separate parts named as outer panel upper and outer panel lower.
• After designing the outer panel the Hemming was created by offsetting the surface with the help of face blend and swept surface.
• The two separate outer panels will be joined using Blanking 

ASSEMBLY IMAGES :

CONCLUSION

The back door outer and inner panel were designed with the help of the styling surface along the tooling direction designed and placed at approprite positons.