Design of Backdoor

DESIGN OF BACKDOOR

Aim:

To design a Backdoor as per given skin requirements and also provide structural reinforcement for the hinge and gas stay areas.

Software:

Siemens NX 12.2

Introduction:

The backdoor is a door through which luggage be loaded or unloaded or in some cases, passengers may also enter or leave the vehicle. A trunk lid type door is not included in this. The most common types of the backdoor are the swinging type and the hatch type, there is also a less commonly used split-hatch type usually used in older models and currently in premium cars.

The structure of the backdoor usually contains 2 to 3 panels depending on the budget of the vehicle. Reinforcements are also placed in required areas for the hinges, gas-stays and striker. While the panels maybe 0.75 - 0.65 mm the reinforcements are required to be 1 - 1.5mm.

While designing the back door curtain design constraints must be followed such as

• Rear visibility requirements
• Hinge, gas-stay and latch reinforcement locations
• Luggage capacity
• The external aesthetic of the vehicle
• position of tail lights.

The backdoor is usually made with multiple selections of materials depending on the budgeting constraints of the vehicle. Steel is the most commonly used material, while aluminium though lighter has a higher cost hence used primarily in premium cars.

Parts of a backdoor:

Inner panel:

The inner panel provides the structure to support the outer panel and reinforcements.

Both the panels are fixed to each other by mastic material or spot welds, but care is taken so that the welds are not seen o the external surface of the door

Outer panels:

The outer panels are the provide the outer structure and provide mounts for the tail lights depending on the model. There may be only one or two outer panels depending on the budget requirements. The outer and inner panels are fixed to one another through hemming and proper reliefs are provided at corners.

Outer upper:

Outer Lower:

Reinforcements:

Reinforcements are provided strategic places where components are fixed or additional strength is needed, they usually range from 1mm to 1.5mm.

The hinge reinforcement is positioned in accordance with the hinge position and the latch and striker. It must be strong enough to hold up the weight of the door.

The gas stay reinforcement is positioned for the easy opening and closing of the door without any interference. Both reinforcements maybe 1-1.5 mm thick

The latch and striker reinforcement is used to mount the door side of the mechanism and is provided with holes to mount the door side of the mechanism.

In some models, the rear window also has a wiper system in such cases a wiper motor mount is also provided on the inner panel.

Assembled Backdoor:

Conclusion:

Thus the rear door is designed as per given skin data and necessary reinforcements and hemming are given.