Design of backdoor
Design of Backdoor/Tailgate
Objective:
1. From styish surface designing the backdoor for cars.
2. To design an inner panel for the back door.
3. To design the necessary reinforcements like Hinge, Gas-stay, Wiper motor, Latch and striker on the basic of engineering standards.
4. The inner panel is subjected to Draft analysis for verifing whether it satisfies requirement of Deep drawing for manufacturing process.
Introduction:
Backdoor is also refered as Tailgate/Reardoor. Backdoor is a closer commidete for the cars, It mainly consists of two - three panels in which outer and inner panel. Backdoor made by aluminum or steel based on the budget of cars, the inner panel is used to improve strength to the outer panel, the inner panel is created by embosses to give more strength. The inner panel and outer panel are joined with hemming process and Mastic sealent. The inner panel consists of latch that is used to lock the door, for opening the backdoor gas stay is used to open the backdoor so it reduce the effort of human to lift or to open, The backdoor is connected to roof by set of two hinges. Backdoor is mainly made of steel or Aluminiom based on the budeget of a car. The inner pannel consists of hinge reinforcement ,Gas stay reinforcement , Latch and striker reinforcement and wiper motor housing.
Important requirement needed for Back door
1.Back door will provided access to the boot space so that we can keep the Luggage into that space.
3.Back door should remain in open condition while keeping luggage.
3.Backdoor should have some strength against collision from rear impact to safeguard passenger.
4.Sealent should be provided ,such that it will not allow any water containt inside the car.
5.Backdoor should have enough rear visibility criteria to see rear of the car.
6.For the strength puropses reinforcement also required.
Types of backdoor based on application purposes.
The backdoor is used in various area depending the opening position as top, side, bottom.
1. Top mounted door
This type of Backdoor is used in a station wagon, pickup truck. Today Modern cars uses this kind of door which consists of both Gasstay and Powered lift support cars. This top mounted backdoor provided great visibility creitria compare to other type of Backdoor.
2.Side mounted door
Side mounted backdoor cars are mainly used in the van type,MPV,SUV ,truck vehicles. These door are more convenient for goods handle purposes and also these doors are easier to open or close door.
3.Bottom mounted door
These backmounted doors are used in the car types such as pickup truck and some luxary cars . These are most convienent types of backdoor in which bottom will spilt is used as support or even as a table.
Lift working mechanisum
1.Gas stay support
This gas stay will be used for tailgate mechanisum from lower car segment to luxary car segmentfor gas stay support, as we seen in hood rod as used as support it required manually support to lift the hood but in backdoor gas stay support will be used compare to hood it does not required manually support to lift the backdoor.
2. Powered lift
In moder days as technology imporoved powered lift will be used for luxary cars, this power lift system is another sophisticated way of trunk or liftgate opening mechanisum which to automatically open and close of the trunk of a bottom, Powered lift system consists of a power latch,antipinch switch, PTG assembly,PTG main switch. When the switch is pressed in the companent or outside the power latch release the latch and entire backdoor is opened.
Design consideeration for Backdoor
1.Class A Surface
2.Inner panel
3.Hinge reinforcement for RH side
4.Hinge reinforcement for LH side
5.Gas stay reinforcement for RH side
6.Gas stay reinforcement for LH side
7.Wiper motor reinforcement
8.Latch and Stricker reinforcement
9.Hemming
Outer panel
From the stylish team we get Class A surface of the outer panel from this surface we can create inner panel and other parts fainly we can assembly them.
Inner panel
By considering the Class A surface as a reference we can create inner panel of the backdoor. The most important part in the inner panel is sealing flange which decides the backdoor will be mounted at the rear side of the car, so it will prevent he water and dust entery of the backdoor car the width of the sealing flange will be 25mm. Embosses will be created for strengthing the part and also dispate the force in the case of rear collision to the outside of the car.
Reinforcement
Reinforcement are the components which will provide extra strength at area where more force will be applied area. The thickness for the reinforcement will be given as 1.5mm
Hinge Reinforcement
Gas stay Reinforcement
Wiper motor Reinforcement
Latch and Stricker Reinforcement
Hemming
Hemming is a forming operation in which the edges of the sheet will be folded over the another part in order to get tight fit.
Manufacturing process for Backdoor
1.Deep Drawing
The deep drawing process is a forming process which occurs under a combination and tensile and compressive conditions.A flat sheet metal blank is formed into a hollow body open on one side or a hollow body is formed into a hollow shape with a smaller cross-section.
In the automotive industry deep drawing is usually carried out using rigid tools.
2.Hemming
Hemming is a forming operation in which the edges of the sheet are folded over another part in order to achive a tight fit. Normally hemming operation are used to connect parts together,to improve the apperence of a part and to reinforce part edges.
3.Piercing
Piercing is a shearing process where a punch and die are used to create a hole in sheet metal or a plate. This process are machinery are usually the same as that used in blanking,expect that the pierce being punched out is scrap in the piercing process.
Force distribution in impact situation
Back door design should be such that to safeguard the passenger and luggage area at rear side
Creating embosses on the backdoor inner panel will give extra strength to the whole assembly in impact situations. Mainly for backdoor V OR Y shaped embosses will br prefered because force will flow away from the center.
Test performed on Backdoor
Following test which will are performed to evalute strength of the back door
1.Bend test
2.Torsion test
3.Dent test
4.Assembly load case
5.Endurance test
Draft analysis
The draft analysis command enable to detect if the part is able to manufacturing or not. This type of analysis is performed based on the colour range identifying zone on the analysed element where the deviation from the draft direction at any point.
Conclusion:
From the stylish team Class A surface Backdoor design is completed by using NX CAD tool, and also necessary reinforcement is created for strengthing the part. Finally the design of backdoor/tailgate is done as per the Industrial standared and Manufacturing techniques.