Design of backdoor
Designing of Back door assy for a car using NX CAD12 with all necessary reinforcements using provided class A surface of outer panel.
Back door: Backdoor are one of the type of door of the vehicle which are located next to the passanger seat which provides access to the luggage compartment. In the most of the cars, these back door are operated with the help of gas stay which in turn reduces the effort required to lift the door.
A Door is a hinged part which is used for entry and exit of the vehicles. Some luxuary cars have powerd 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 door this is because it enters the passenger compartment. The naming is mainly used in Europe countries. In case of safety, the backdoor designed should meet the safety requirement of the rear collision.
The trunk (North American English) or boot (British English) of a car is the vehicle's main storage or cargo compartment, often a hatch at the rear of the vehicle. It is also called a tailgate.These doors can be operated manually or electric powered. In most of the luxury cars door is electrically operated. Ii involves a very major role during rear crash cases. so our design must be obey crash requirements. the institute of highway saftey analyse the diffrent accidents and they set a test to rate our car. so these rating depends uopn the design of the trunk and material used, flenges, embosses, type of joining of inner panel and outer panel etc.
Types of Backdoor:
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
1.Top mounted:
This type of back doors is used in a station wagon, pickup trunk and some of the spot utility vehicles. Today's modern cars use top mounted tailgating system which are both powered and also gas stay supported. These top mounted tailgates provide greater rear visibility compared to side mounted or backdoor which have center pillars in it .
2.Side mounted door:
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 door also save 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 are used in the car type such as car, pickup truck and some luxuary 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.
Back door is operated by two types of comodities:
The main purpose of these mechanisims is to open the back door without heavy efforts, because the backdoor have different parts and the weight of the back door is high, so we are not able to open the back door manually, so we introduced these two types comodities, and these also decides the premium of the car, mostly the electrically operated used in premium cars.
1) Gas Stay Powered
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 tailgate consist of a hinge, door, gas stay and some rubber beadings for sealing of door.
2) Electrically Operated
Elecrically operated system is another sophisticated way of trunk or liftgate opening mechanism which is to automatically open and close of the trunk and release of the latch by the touch of a bottom. Powered trunk Lift system consists of a power latch, anti pinch switch, PTG assly, 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 in order to avoid accidental hand insertion during the operation of the door.
Manufacturing methods:
Recently, there have been two approaches to reducing automobile weight. One is by using material lighter than steel and the other is by redesigning the steel structure. Althrough the former seems very effective, it is very expensive so that it may only be used for an expensive automobile industry is trying to use steel, which is not costly and recyclable. Light weight steel can be achieved by improving the performance of the structure or adopting by improving the performance of the structure or adopting new manufacturing techniques. One of the efforts is the ULSAB (Ultra Light Steel Auto Body) concept. ULSAB suggests three main weight reduction techniques such as hydro forming and the Tailor Welded Blank (TWB).
Tailor Welded Blank:
A Tailor Welded Blank is a blank that is compared of two seperate pieces of sheet metal that have been welded together prior to stamping. Tailor Welded Blanks allow the welding of the different grades, different thickness or different corrosion coating together in order to give the properties needed in differeent areas, without increasing the number of tools needed to form the part and eliminating the fit ability concerns. They also allow a high degree of flexibility in designing parts and large blanks can be formed from much smaller sheets. The use of Tailor Welded Blanks would reduce the weight of the car. Having the ability to selectively place different thickness of materrial would result in weight reductions. An example of this production is the door inner panel. The only strength requirement on a door inner is in the region where the hinges attach to the panel.
Backdoor Assembly:
1.Inner Panel
2.Outer Panel
3.Hinge Reniforcement.
4.Gas Stay Reniforcement.
5.Wiper Motor Reniforcement.
6.Latch and Striker Reniforcement.
1.Inner Panel: The inner Panel is a component which 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 the assembly cost and eliminates any fit ability problem.
2.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, rush 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 lisence plate mountings. Most of the hatch back cars have the provision for wiper motor.
3.Hinge Reinforcement: Hinges support the weight of the whole backdoor. Hence a reinforcement are provided here too. Emboss is designed such that the hinges should operated freely. The electrical wiring looms are through the holes along the periphery to keep them hidden.
4.Gas stay Reinforcement: An angled or Diabolic emboss is provided for the gas stay mounts. The angle makes it easy to be machined
and stamped. It is reniforcement with a thicker sheet.
5.Wiper motor Reinforcement: A dedicated space near the window 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.
6.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.
Another purpose of the emboss design is to distribute impact force towards hinges and latch assembly which are reniforced and can absorbe them.
Final Assembly:
Conclusion:
The back door outer and inner panel were designed with the help of styling surface along the tooling directions and by applying solid and sheet modelling methodologies and according to the engineering standards, the design of back door challenge was completed by using NX CAD .