Design of backdoor

Back Door Challange

Aim:

• To design a back door of a car by using the given styling surface.
• To provide necessary reinforcement and embosses.

Introduction:

A back door or tailgate is the rear side of a car which gives access for the boot space to store luggage, spare wheel, etc. These doors can be operated manually or electric powered.

The backdoor consists of the following basic components:

1. Backdoor Inner Panel
2. Backdoor Outer Panel Upper
3. Backdoor Outer Panel Lower
4. Hindge Reinforcements
5. Gas-Stay Reinforcements
6. Latch and Striker Reinforcement
7. Wiper Motor reinforcement

Types of Backdoor:

1. Top Mounted Door

2. Side Mounted Door

3. Bottom Door

Repairing the Styling Syling Surface:

There were some irregularities in the given surface therefore, the surface was repaired and smoothen up. The final surface of the backdoor is as shown in the figure.

After repairing the surafces, the door is divided into two parts viz. Door Outer Upper and Door Outer Lower.

Desing Procedure:

1. Tooling Direction

A tooling direction was set for the deep drawing operation as shown in the figure. It is desirable in drawing operations to maximize material flow in the plane of the sheet and to minimize the material flow in a direction perpendicular to the plane of the sheet.

2. Creating Sealing Flanges

A Sealing flange was created by offsetting the outer panel to specific distance. The width of the flange is 25mm.

3. Connnecting Flange

A connecting Flange is created between the sealing flange and inner panel flange as shown in the figure.

4. Windsheld Panel

5. Mastic Flange

This mastic flange is created by punching the inner panel during manufacturing. One important consideration that should be accounted is the corner relief to prevent stress concentration at the corners.

Overall Representation of Flanges

6. Creating Embosses and Cutouts

7. Mounting Regions

Reinforcements:

These are the parts that provides additional strengths to the structure locally. Emboss alone is not enough to handle the weight of the gas stay, wiper motor, hindges, etc. therefore these reinforcements are provided to increase its strengths on that area.

Following are all the reinforcements provided to the car backdoor:

1. Hindge Reiforcement LH

2. Hindge Reinforcement RH

3. Gas-Stay Reinforcement LH

4. Gas-Stay reinforcement RH

5. Wiper Motor Reinforcement

6. Latch and Striker Reinforcement

Positioning of Latch and Striker:

For the positioning the latch and striker, a trajectory passing through a midpoint of line/axis of the two hindges mounting regions is created. Also, a perpendicular line is drawn at the midface of the striker and this line should be tangent to the circle drawn as shown in the figure.

The Hindge axis is as shown below:

The below figure shows the trajectory followed by the striker which is tangent to the circle.

Hemming:

It is a process of attaching the outer panel of the backdoor to the inner panel of the backdoor by adding extra material on the outer panel and made to wrap around the inner hood panel. Some considerations should be taken while hemming such as the clearance distance. The hemming of the backdoor is as shown in the figure below:

One more important to be considered while hemming is corner reliefs which is as shown:

Mastic Data:

Draft Analysis:

Draft Analysis is a method of checking the draft angle on various faces of a part in a particular direction. The draft angle should be positive for the feasibility of manufacturing the part. Generally, we take draft angle 7 or greater than 7. The draft analysis was conducted for the following sections considering tooling direction as the vector:

1. Backdoor Inner Panel

2. Backdoor Outer Surface

Conclusion:

Hence, the backdoor is designed with all the necessary reinforcements and embosses along with considering all the important design criteria.