Design of backdoor
BACKDOOR :
Aim:
Using the provided styling surface to come up a back door design and using apropriate design methodologies and make the necessary reinforcement and embosses.
What is a backdoor?
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 vehicles which are located nest 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 efoort 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 stadio wagons are sold as 3 door or 5 door models . in this case , the rear hatch is classifed as door this is because it enters the pasenger compartment . the naming is mainly used in Europe counteries . in case of safety , the back door designed should meet the safety requirement for the rear collision.
TYPES OF THE BACK DOOR 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.
TOP-MOUNTED:
This type of back doors is used in a station wagon , pickup truck and some of the sport utility vehicles.
Todays 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 side-mounted or bar doors which have canter pillars in it.
SIDE MOUNTED DOORS:
As the name signifies 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 easiler commpared to top-mounted doors.
These are doors generally smaller in size and can be easily accessed these doors are more convenient for the good handelers for long pipe and lenghty 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 / SPLIT TYPE:
The bottom type or split type backdoor system are used in the car type such as estate type car. pickup trucks and some luxury SUVs.
These wre the most convenient type of back door in which the bottom split is used as a support or even as a table for tour going people.
TYPES BASED ON WORKING MECHANISM.
GAS STAYS TYPE:
Gas stay types backdoor/liftage/tailgate is an ideal and most commonly used tailgate mechanism from lower segment car to loxury car segment. the ideal components of tailgate consist of ahinge, door, gas stay and some rubber beadings for sealing of door which is shown in the image belowa;
POWERED LIFT SYSTEM:
Power trunk lid system is another sophisticated way of trunk/ liftgate opening mechanism which is to automatically open of the trunk/liftgate and release of the latch by the touch of a button. The following image shows the component as used in the powered trunk/back door lift system.
Powered trunk lift system consists of a power latch , anti -pinch switch , PTg assy , PTG main switch. when the switch is predded in the compartment or outside the power latch release 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 redusing automobile weight . One is by using material lighter than steel and other is by redesigning so that it may only be used for an expensive automobile . There fore , the automobile industry is trying to use steel, which is not costly and recylable . LIghtweight steel can be achieved by improving the performance of the structure or adopting new manufacturing techniques . one of the efforts is the ULSAB [ ultare -light steel auto body ] concept
ULSAB suggests there 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 comprised of two separate pieces of sheet metal that have been welded together prior to stamping . tailor welded blanks aloow the welding of the different grades, different thickness or different corrosion coating together in order to give properties needed in different 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 material woluld result in weight reducations. An example of this used in 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.
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 compartment 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 altractive finishes. The outer panel also has the provisions for the tail lamp, rear fog lamp and also has the provision for licence platemountings. mast of the hatchback cars have the provision for wiper motor.
DRAMT ANGLE IS 5 :
DESSIGNING THE REINFORCEMENT:
The thickness provided for all reinforcement is 1 mm.
1. HINGE REINFORCEMENT .
2. GAS STAY REINFORCEMENT.
3. WIPER MOTOR REINFORCEMENT.
4. LATCH REINFORCEMENT.
All the reinforcement were created using the same method , first the linked body was created separaetly for each with the help of extract geometry and then the required portion was trimmed out then thickened.
REINFORCEMENT:
The reinforcement provided is of 4 numbers which consist of hinge reinforcement , gas stay reinforcement , wiper motor reinforcement and latch / striker reinforcement .
HINGE REINFORCEMENT:
Hinges enable the opening and clossing of the back door . one end of the hinges is fixed on the backdoor and the other end on the roof , on both sides . hinges can be placed outside or inside the backdoor.
The hinges reinforcement are added to compenstate for the weak region due to acting load over it .
GAS STAY REINFORCEMENT:
Gas stay is a device used for supporting the back door in its open . Gas stay requires no manpower and is engaged into support position automatically as the back door opens. one end of the gas stay is fixed on the backdoor and the other end on the body side or on the back door stationary area.
Embossing is provided at the gas stay mounting ara to compensate for weakness and improve strength.
WIPER MOTOR REINFORCEMENT :
Wiper motor reinforcement is created to mount the wiper motor assembly.
LATCH AND STRIKER REINFORCEMENT:
The latch & Striker forms the locking mechanism of the backdoor with the car . due to regular opening , closing , and over slamming of the backdoor , there is stress developed in the latch and striker area. To compensate for the same, reinforcements are added in this area.
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 is turn to avoid of the hemming defects such as wave- like OR wrinkle formed surface.
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.
FR. VIEW
BACKSIDE VIEW
SIDE VIEW
ISOMERTIC VIEW
CONCLUSION:
Thus the design of BIW fixtures of a backdoor of a car has been designed using NX_CAD.