BACKDOOR

AIM :

To Design the Upper and Lower Outer panels, The Inner panel with the necessary reinforcements by following the master section with the design parameter for the given Class A or Styling surface using NX CAD software.

INTRODUCTION OF BACKDOOR :

A door is a hinged part that is used for entry and exit of the vehicles. Backdoors are one of the type doors of the vehicle which are located next to the passenger seat which provides access to the luggage compartment. In most the car, these backdoors are operated with the help of gas stay which in turn reduces the effort required to lift open the door.

Some luxury cars have a powered backdoor which in turn is driven by an electric motor. This kind of system is also called a Powered trunk lid system. Hatchback or station wagons are sold as 3 or 5-door models. In this case, the rear hatch is classified as a door this is because it enters the passenger compartment. The naming is mainly used in Europe countries.

TYPES OF BACKDOOR :

1. Top-mounted door.
2. Side-mounted door.
3. Bottom-type door.

1. TOP MOUNTED DOOR :

This type of backdoor is used in a station wagon, pickup truck and some of the sports utility vehicles. Today's modern cars use top-mounted tailgating systems which are both powered and also gas stay supported. These top-mounted tailgates provided greater rear visibility compared to side-mounted or backdoors which have center pillars in them.

2. SIDE-MOUNTED DOOR :

As the name signifies side-mounted doors are the one which is used in the Van types MPVs, SUVs, and 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 by pacts. Loading and unloading items in the side-mounted door is a lot easier.

3. BOTTOM TYPES DOOR :

This bottom-type backdoor system is used in car types such as cars pickup trucks and some luxury SUVs. These are the most convenient type of backdoor in which the bottom split is used as a support or even as a table for the tour-going people.

TYPES OF MECHANISMS FOR REAR DOOR :

1. Gas stay.
2. Powered lift system.

1. GAS STAY :

Gas stay type backdoor is an ideal and most commonly used tailgate mechanism from the lower segment to the luxury can segment. The ideal components of the tailgate consist of a hinge, gas stay, door, and some rubber beadings for the sealing of the door.

2. POWERED LIFT SYSTEM :

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

BACKDOOR DESIGN USING NX CAD

• DESIGN CONSIDERATIONS :

1. Rear visibility.
2. Boot space and accessibility.
3. Support structures like hinges and gas stay.
4. Rear crash regulations.
5. Gap and flush requirement.
6. Sealing flange.
7. Joining techniques such as hemming, spot welding, etc.
8. Mounts for wiper motor and tail lamps.

• INTRODUCTION :

The Backdoor or the tailgate is the door for the luggage cabin. This houses the tail lamp and the wipers and may also house the license plate in some cases. In case the license plate is mounted on the backdoor it will also have the license plate lights mounted on it. The Backdoor also consists of the inner panel and reinforcements for the gas stay, striker, wiper motor and hinges. In case of a rear collision, the vehicle back is responsible for the absorption of the maximum amount of force and it needs to dissipate the force towards the side panels via C-Pillar instead of transmitting it into the passenger cabin.

• UPPER AND LOWER OUTER PANEL :

These two panels were referred to as the styling part which provides the good aesthetics of the vehicles. It is hemmed with the inner panel. It also holds the tail lamp and wipers. In some cases, it also holds a rear camera is helps for reverse parking.

• INNER PANEL :

The inner panel is the one that provides strength to the outer panel. It holds the reinforcements for gas stay, hinge, wiper motor and striker reinforcements were attached to add strength locally and they lose some strength as they are holding loads. Embosses were made on the inner panel to improve the strength of the inner panel and dissipate the force away from the passenger cabin.

It has a flat surface known as a sealing flange which follows the same line as the rubber part mounted on the roof and side door flange. It will be positioned perpendicularly over the rubber part to prevent water from entering the cabin.

• REINFORCEMENT :

• TRAJECTORY OF BACKDOOR :

The Backdoor is the swinging part which rotates about the hinge axis. The position and orientation of the striker are important for proper opening and closing of the backdoor. The positioning is done by sketching a circle with the center as the axis of the hinge which passes through the striker at the appropriate position concerning the inner panel.

• DRAFT ANALYSIS :

Draft allows for the component to be released from the mould most parts or applications require a minimum of 0.5 to 1 deg. Draft angle and 7 deg. Draft angle is widely used as per the norm.

Every part which is manufactured from press tool or other forming tools require some positive draft on faces which are parallel to the tooling axis. If we don't give draft negative on these faces it will stick to the mould surface.

INNER PANEL DRAFT ANALYSIS :

HINGE REINFORCEMENT DRAFT ANALYSIS :

GAS STAY REINFORCEMENT DRAFT ANALYSIS :

WIPER REINFORCEMENT DRAFT ANALYSIS :

STRIKER REINFORCEMENT DRAFT ANALYSIS :

• HEMMING PROCESS :

Hemming is the process of wrapping the flange of the outer panel to the flange of the inner panel so that are fits rigidly. After the hemming process, the sealants were applied along the edge of the flange of the outer panel so that water tightness was achieved.

This image is a cross-section of the inner and outer panel backdoor joined by the hemming process.

Usually, the reliefs were provided at the hemming flange to avoid the stress developed during the hemming process.

This image Some hemming reliefs.

• FINAL IMAGE OF BACKDOOR :

• CONCLUSION :

Thus backdoor has been designed using appropriate methodologies.

This is the part file :

https://drive.google.com/file/d/1wZfezFXv8PcbAQfAtFAGtyAca3bIIG9s/view?usp=sharing