Challenge

Design of backdoor

SSasi Kumar10 Oct 2022

CAR BACK DOOR DESIGN

Objective:

Use the provided styling surface to came up with backdoor design using the appropriates design methodologies and provide the necessary reinforcement and emboss. Need to include all part files and assembly and also perform the draft analysis of the design

What is backdoor?

A tailgate(backdoor) is a door at the back of a truck or car, that is hinged at the bottom so that it opens downwards. Like hood and side doors, back door is also a swinging closure commodity. These doors can be operated manually or electric powered. In most of the luxury car door is electrically operated. it involves a very major role during rear crash cases. so, our design must obey crash requirements. the institute of highway safety analyse the different accidents and they set a test to rate our car. so, these rating depends upon the design of the trunk and materials used, flanges, embosses, type of joining of inner panel and outer panel etc.

Types of Backdoors based on working positions:

The door or opening of a cargo area may be hinged at the top, side & bottom. If the door hinged in the bottom it is called as a tailgate.

1.Top mounted

2.Side mounted doors

3.Bottom type

Top mounted backdoor

This types backdoor placed in the top side of the vehicle. This type of back doors is used in a station wagon, pickup trunk and some of the sport utility vehicles. Today's modern cars use top mounted tailgating system which are both powered and also gas stay supported. This type of back door has either yeah gas stay operated or electric operated. This type back door will be operated by a gas stay and normally mostly of the car use this method due cost effective and easy to use. In the electric operated backdoor was working based on electric motor and this type of car either in specific nor high end vehicles.

Side mounted doors:

As the name signifies the side mounted doors are the one which is used in the van type MPVs, SUVs, pickup truck vehicles. These side mounted doors or barn doors are a lot easier compare to top mounted doors. These doors are generally smaller in size and can be easily accessed. These doors are more convenient for the goods handlers for long pipe and lengthy components where one door is kept open. These doors also save accidental head impacts. It is a lot easier to load and unload items in the side mounted doors

Bottom mounted backdoor:

This bottom type of backdoor system is used in the car type such as car, pickup truck and some luxury SUVs. These are the most convenient type of back door in which the bottom split is used as a support or even as a table for the tour going people.

COMPONENTS OF THE BACK DOOR

outer panel
Inner panel
Gas stay
Hinge mounting
wiper mounting
Striker

OUTER PANEL UPPER AND LOWER:

Outer panel is the styling surface of the backdoor. Glass for rear visibility is mounted on the outer panel upper Rear lights are also mounted on the outer panel upper. Number plate is mounted on the outer panel lower. Spot welds and other manufacturing process should be done only on the inner panel because the outer panel is the styling surface which should not have any scratches or welds Because it affects the style of the car which leads to bad impression on the customers.

INNER PANNEL:

The inner 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, 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 inner panel was designed by offsetting the given class ‘A’ surface as per the given master section. The inner panel consists of Embosses and mastics.

Car backdoor inner panel is made of either steel or aluminium. Most of the luxury car's inner panel are made of aluminium because of its properties, But the cost of aluminium is high.

	Steel	aluminium
PARTS	Parts are stamped	Parts are casted
REINFORCEMENTS	Necessary	Can be neglected
THICKNESS	Constant	Can be Varied
COMPONENTS	More	Less in number
WEIGHT	More	Lighter
COST	less in cost	More as compared to Steel

HINGE REINFORCEMENT:

Hinges support the weight of the whole backdoor. Hence, the reinforcements must be provided there too. The emboss is designed in such a way that the hinges should operate freely. The hinge is connected to the rear roof of the car.

LATCH AND STRIKER REINFORCEMENT:

At bottom of the panel, reinforcement and emboss are given to accommodate the latch and striker assembly Generally key operated or automatic remote controllable mechanism is used to keep the door open or closed. The actuators, receivers and other electronic vices are mounted on the inner panel only.

WIPER MOTOR REINFORCEMENT:

Wiper is used to wipe out the rain waterfalls on the backdoor window. It is actuated by the motor which is mounted on the inner panel. Due to the vibration and heat created by the motor the inner panel where the motor is mounted gets deform and the parts attached to the motor starts to vibrate which leads to poor NVH. So, we have to provide the reinforcement where the wiper motor is placed.

DRAFT ANALYSIS:

The draft analysis technique is used to analyze whether our part model created in CAD is manufacturable based on the draft condition applied. Here the part should get easily removed from the panel dies (in case of Sheet metal part) or Mold (in case of plastic). Draft analysis is the command enable you to detect if the part you draft will be easily removed. This type of analysis performs based on colour rains identification zones on the analysis element where the deviation from draft direction at any point corresponding to the specific value. This value is from both negative from positive direction. When the negative value represents good rating and positive value more than 5 will be risk high. That represent the smoothness of the part. In parts smoother more good design. In our design we going to perform this analysis to roof, front rail, rear rail, bow rails and centre rail. And check whether the roof is smoother and less in rating.