Design of backdoor

The backdoor is an important commodity of a vehicle. It not only allows user access to the rear luggage storage space, but it also provides safety to the occupants in case of a rear collision. It is usually supported by 2 gas stays. The backdoor holds the number plate, number plate light, door handle, taillights, rear windshield and a windshield wiper and its motor.

In this challenge, I have designed the backdoor of a passenger vehicle from the given styling data. This component is itself an assembly of multiple components which are:
• Inner Panel
• Outer Upper Panel
• Outer Lower Panel
• Hinge Reinforcements X 2
• Gas Stay Reinforcements X 2
• Wiper Motor Reinforcement
• Stricker

As the Inner Panel is the most critical component of this assembly, it was created first. Initially, the sealing flange was created as shown:

Force Direction:
The design of the embosses on the inner panel divert the impact force away from the passenger cabin.

Mastic Sealing:
A gap of 5 mm was maintained between the Inner Panel was and the Outer Upper Panel to as mastic sealant is filled in this gap for bonding these two parts.

Draft Analysis for Manufacturing:
The Inner Panel is designed to be a single-piece stamped part with 0.75mm thickness. From the tooling requirements, an opening angle of 7° is maintained.

Hemming:
The Outer Upper Panel and Outer Lower Panel are also sheet metal parts with 0.75 mm thickness each. These are wrapped around the Inner Panel via the hemming process. Reliefs are required to be provided at the sharp corners for proper hemming operation.

Reinforcements:

Reinforcements are provided to strengthen a localized area of a component. In this assembly, reinforcements are provided for hinges, gas stays and wiper motor.

Trajectory Circle:

When the backdoor is closed, the Stricker gets locked into the latch on the vehicle body. Thus, for correct operation of the backdoor, the Stricker needs to follow a trajectory circle with center as the Hinge axis of the backdoor.