Design of backdoor

Aim :

To develop the car's Backdoor(Tailgate) with the reference of given skin data per engineering standards using NX12.

OBJECTIVE :

To create the following components of the backdoor panel from the given styling surface.

• Inner panel,
• The upper outer panel,
• Outer lower panel with the
• Hinge reinforcement (left and right)
• Gas stay reinforcement (left and right)
• Latch reinforcement

Back Door:

A Door is a hinged part that is used for entry and exit of the vehicles. Backdoors are one of the types of doors of the car which are located next to the passenger seat and provide access to the luggage compartment.

In most cars, these back doors are operated with the help of gas stay which in turn reduces the effort required to lift the door. Some luxury cars have a 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 doors or 5 doors models.

In this case, the rear hatch is classified as a door this is because it enters the passenger compartment. The naming is mainly used in Europe countries. In case of safety, the backdoor design should meet the safety requirement of the rear collision.

The Back door is typically hinged but sometimes attached by other mechanisms such as tracks, in front of an opening used for entering and exiting a vehicle.

A vehicle door can be opened to provide access to the opening, or closed to secure it. These doors can be opened manually, or powered electronically. Powered doors are usually found on minivans, high-end cars, or modified cars.

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

1. Top mounted

2. Side-mounted doors

3. Bottom type

1. Top mounted:

This type of back door is used in a station wagon, pickup trunk, and some sport utility vehicles. Today's modern cars use top-mounted tailgating systems which are both powered and also gas stay supported. These top-mounted tailgates provide greater rear visibility compared to the side-mounted or backdoor which has center pillars in it.

2. Side-mounted door:

As the name signifies the side-mounted doors are the ones that are used in the van-type MPVs, SUVs, and 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 pipes and lengthy components where one door is kept open. This door also saves accidental head impacts. It is a lot easier to load and unload items in the side-mounted doors

3. Bottom type:

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

Types based on Working Mechanism:

1. Gas Stays type.

2. Powered Lift system.

1. Gas Stay type:

Gas Stay type backdoor is an ideal and most commonly used tailgate mechanism from lower segment car to luxury car segment. The ideal components of the tailgate consist of a hinge, door, gas stay, and some rubber beadings for the sealing of the door.

2. Powered Lift System:

The power trunk lift system is another sophisticated way of trunk or liftgate opening mechanism which is to automatically opens and closes the trunk and releases the latch with the touch of a bottom. The powered trunk Lift system consists of a power latch, anti-pinch switch, PTG assay, and PTG main switch. When the switch is pressed in the compartment or outside the power latch releases the latch and the entire backdoor is opened. The anti-pinch switch is located to avoid accidental hand insertion during the operation of the door.

Some terminologies :

"Latch" is a device employed to maintain the door in a closed position relative to the vehicle body with provisions for deliberate release (or operation).

“Hinge” is a device used to position the door relative to the body structure and control the path of the door swing for passenger ingress and egress.

Gas Stay type backdoor is an ideal and most commonly used tailgate mechanism from lower segment car to luxury car segment. The ideal components of the tailgate consist of a hinge, door, gas stay, and some rubber beadings for sealing the door.

Design Consideration :

• Visibility Criteria
• Latch and Stricker Position
• Hing Position
• Gas Stay Position
• Space Availability
• Drain Holes
• Hemming and Relief area's

Components of Back Door :

The Components of the Back Door are as follows,

1. Inner Panel
2. Outer Panel
3. Hing Reinforcement
4. Latch and Stricker Reinforcement
5. Gas stays Reinforcement
6. Wiper motor Reinforcement

Inner Panel :

The inner Panel is a component that is used for strengthening the door and it is one of the most important components on which all accessories are mounted like hinges, glass guide channel, mounted 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 and 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 the multi-stage which has the property of scratch resistance, rust prevention, and smooth and attractive finishes. The Outer panel also has provisions for the tail lamp, and rear fog lamp and also has the provision for license plate mountings. Most hatchback cars have the provision for a wiper motor.

Hinge Reinforcement :

Hinges support the weight of the whole backdoor. Hence reinforcement is provided here too. Emboss is designed such that the hinges should be operated freely. The electrical wiring looms are through the holes along the periphery to keep them hidden.

Gas stay Reinforcement :

An angled or Diabolic emboss is provided for the gas stay mounts. The angle makes it easy to machine and stamp. It is reinforced with a thicker sheet.

Wiper motor Reinforcement :

A dedicated space near the rear windshield glass is left for wiper motor assembly. A cavity is placed in the middle of the panel for the necessary components in the assembly as well as other accessories.

Latch and striker Reinforcement :

At the bottom of the latch and striker assembly. Generally a key-operated or automatic remotely controllable locking mechanism is used to keep the door closed and open.

Hemming :

TOOLING DIRECTION :

LATCH AND STRIKER ASSY TRAJECTORY :

DRAFT ANALYSIS :

Conclusion :

The backdoor sheet metal part body for the Hatchback car was successfully created taking into consideration all the attachments embossments, hemming, and finally with the proper draft angle so that the final component is manufacturable. The approach to design the inner panel was taken in such a way that it dissipates the force outwards in the various crash test.