Design of backdoor

DESIGN OF BACK DOOR

Objective:-

• Designing a back door using all engineering design rules by taking the reference of given class A surface
• Positioning the latch and stricker by creating the back door opening axis
• Creating the reinforcements and providing the embosses

Some important terms:-

Door:-

A door is a hinged part which is used for entry and exit of the vehicles. Back doors 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 of the cars, these back doors are operated with the help of gas stay which in turn reduces the effort required to lift open the door. Some luxury cars have 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 door or 5 door models. In this case, the rear hatch is classified as door this is because it enters the passenger compartment. The naming is mainly used in Europe countries. In case of safety, the back door designed should meet the safety requirement for the rear collision.

BACK DOOR ASSEMBLY:-

The back door assembly of a hatchback or SUVs has the following components.

• Inner panel
• Outer panel
• Hinge reinforcement
• Gas stay reinforcement
• Wiper motor reinforcement
• Latch/striker reinforcement

INNER PANEL:-

The inner door panel is a component which is used for strengthening the door assembly and it is one of the most important components on which all accessories are mounted like hinges, glass guide channel, moulded trim, latch etc. The possible method is the integration method. In the integration method, the part is stamped out of a single blank. This reduces the number of tools needed; the assembly cost and eliminates any fit ability problem.

Outer panel:-

The outer panel of the back door is similar to other BIW components where it is the aesthetic part of a vehicle. The coating provided is of multi-stage which has the property of scratch resistance, rust prevention and smooth and attractive finishes. The outer panel also has the provisions for the tail lamp, rear fog lamp and also has the provision for licence plate mountings. Most of the hatchback cars have the provision for wiper motor.

REINFORCEMENT:-

The reinforcement provided is of 4 numbers which consist of hinge reinforcement, gas stay reinforcement, wiper motor reinforcement and latch/striker reinforcement.

HEMMING OPERATION:

Hemming is a mechanical joint design which is used for joining inner and outer closure panels as found indoors, hoods, bonnets and lift gates. To increase crash resistance the gap between the hemmed panels is filled with a high-strength adhesive which also prevents from corrosion.

Hemming relief:-

Hemming reliefs are cut-outs which are provided on the hemmed corner of the panel assembly which in turn to avoid some of the hemming defects such as wave-like OR wrinkle formed surface as shown below:

The back door design requires two locations where the roller type hemming relief is required which are shown below:

Latch/striker rotation angle:-

This rotation angle of the line denotes the line of action of backdoor when hinged to the body of the car.

Section view:-

The cross-section view of the back door is shown below which presents the hemming done between the outer panel and inner panel.

Draft analysis:-