Design of backdoor

Aim -

To design back door using the given styling surface with appropriate design methodologies and providing the necessary reinforcements and embosses.

OBJECTIVE -

• From the given styling surface, develop a back door using appropriate design methodologies.
• The objective of this project is to design a BIW Back Door of a car with an Inner Panel, Outer Panel, and Reinforcements for the Hinges, Gas stay, Wiper Motor, and Latch by following the engineering standards.
• The Inner Panel must be subjected to Draft Analysis for verifying whether it satisfies the Deep Drawing requirements for the tooling direction created in the design.

INTRODUCTION-

The Back Door of a car is the rearmost part of the vehicle which gives access to the trunk space of the car. The rear door also supports the reinforcements and added weights of the Wiper Motor, Gas Stay, Tail Lamp, and Latch and Striker. The Backdoor/tailgate is one of the closure commodities in BIW sheet metal design.The backdoor has a lot of components inside and is designed to incorporate them easily. It affects the rear visibility and luggage area. The material used for door manufacturing depends on the budget and performance of the vehicle. Mainly Aluminium and Steel will be used whereas low-budget vehicles use Steel, making the manufacturing process easy and cost-efficient since it follows the Stamping of Moulds.

Design Considerations For a Back Door -

1. Rear Visibility
2. Boot Space and accessibilit
3. Support Structures like hinge and gas stays
4. Mounts for wiper motor, tail lamps, and other wiring loops.

Design Methodology-

1. Outer Panel (Upper and Lower)
2. Inner Panel
3. Reinforcements
4. Draft Analysis

1.Outer Panel -

1.1.Outer Upper Panel -

• The Outer Upper Panel was Extracted from a styling surface.
• The thickness provided for the outer panel is 0.75 mm
• Hemming is provided with the corner relief.

1.2.Outer Lower Panel -

• The Outer Upper Panel was Extracted from a styling surface.
• The thickness provided for the outer panel is 0.75 mm
• Hemming is provided with the corner relief.

2.Inner Panel -

• Inner panel design starts with sealing flange after that connecting flange.
• After windsheild area and mastic area,Emboss for child parts.
• The embosses were created in ‘V-Shape or Y-Shape’ so that if the vehicle undergoes the crash then the force dissipates over it which reduces the damage transferred to the trunk space.
• The mastic sealant is used to fix the inner panel with the outer panel which increases the NVH factor and stiffness of the back door.
• The thickness provided for the inner panel is 0.75 mm.
• Locations - 1.Red Circles - Hinge Location

2.Green Circles - Gas-stay Location

3.Blue Circle - Wiper Motor Location

4.Black Square - Mastic Flanges

3.Reinforcements -

Reinforcements are gievn to increase the strength of the components.

3.1.Hinge Reinforcement -

• Hinges enable the opening and closing of the back door. One end of the hinge is fixed on the backdoor and the other end on the Roof, on both sides. Hinges can be placed outside or inside the backdoor.
• The hinge reinforcements are added to compensate for the weak region due to the acting load over it.
• All the reinforcements were created using the same method, first, the linked body was created separately for each with the help of extract geometry and then the required portion was trimmed out and then thickened for 1.5mm.

3.2.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.

3.3.Wiper Motor Reinforcement -

• Wiper motor reinforcement is created to mount the wiper motor assembly.

3.4.Latch Reinforcement -

• The Latch & Striker forms the locking mechanism of the backdoor with the car. Due to regular opening, closing, and over slamming of the backdoor, there is stress developed in the Latch and Striker area. To compensate for the same, reinforcements are added in this area.

4.Draft Analysis -

• The draft analysis will be performed for the tooling direction created at first and checked that the model is suitable for manufacturing.

• Then to get a complete green portion the necessary changes to the draft angle of the embosses were carried out by optimizing the model.

• The Draft Analysis command enables us to detect that the part drafted will be easily removed or not.

• 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.

Conclusion -

Thus the back door was designed from the given styling surface and Draft analysis is also done on the inner panel to check the manufacturing conditions. In this challenge i learned to design the Inner panel, the Outer panel, Wiper Motor reinforcement, Hinge reinforcement, Gas Gtay reinforcements, Latch and Striker reinforcement and its position.