Design of backdoor
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BACK DOOR DESIGN REPORT
INTRODUCTION:
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 vehicle which are located next 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 effort 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 station wagons are sold as 3 door or 5 door 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 back door designed should meet the safety requirement for the rear collision.
Types of the back door
1.Top-Mounted:
This type of back doors is used in a station wagon, pickup truck an
d some of the 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 side-mounted or bar doors which have canter pillars in it.
2.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 easier compared to top-mounted doors. These doors are generally smaller in size and can be easily accessed.
3.Bottom type:
This bottom type backdoor system are 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.
Types of mechanisms for Rear Door:
Gas stays:
Gas stay types backdoor/liftgate/tailgate 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.
Powered lift system:
Power trunk lid system is another sophisticated way of trunk/liftgate opening mechanism which is to automatically open and close of the trunk/liftgate and release of the latch by the touch of a button.
Materials Selection:
The selection of material plays a major role in determining the overall weight of the back door. The common materials used are Steel & Aluminium. The density of Steel is higher than Aluminium thus adding more weight to the door. The material used in the manufacturing of the backdoor depends upon the budget of the car, most low-cost vehicles use steel as it is cheaper compared to Aluminium
The Different panels or regions are as follows:
§ Inner Panel.
§ Outer Upper Panel.
§ Outer Lower Panel.
§ Hinge Reinforcement LH & RH.
§ Gas Stay Reinforcement LH & RH.
§ Wiper Motor Reinforcement.
§ Latch and Striker Reinforcement.
1. BACK DOOR OUTER PANEL
In this design back door is created as two different parts back door outer panel upper and lower. This outer panel designed based on visibility criteria and proper reliefs provided at the corner for hemming operation. The thickness of outer panel is 0.75 mm .
2.BACK DOOR INNER PANEL
Back door outer panel designed based on hinge, gas stay, wiper motor position and reinforcement as well as visibility criteria. Suitable tooling direction is created for trouble free manufacturing process. In this design stamping operations created based on this tooling direction. Embosses are provided in this design for force dissipation. In this design appropriate clearance given in mastic areas. The inner panel thickness is 0.75 mm
3.Mastic Area
Mastics sealants used for joining of outer panel and inner panel. It increases the strength of back door and good NVH. So accurate clearance given for mastic sealant.
Reinforcements in inner panel
Hinge reinforcement.
In this design hinges provided on the top side of the door. Appropriate reinforcement given for hinge mounting areas to improve the strength.
Gas stay reinforcement
Gas stays support the weight of the back door while they are open. More load act on this region, So suitable reinforcement provided for better strength. It is spot welded on the inner panel.
Wiper motor reinforcement
Reinforcement provided in this region for fixing the wiper motor.
Latch and striker reinforcement.
The striker is designed to create a tight fit between the door and the seal on the cab. The door open and shut several times in a day. So, more force acting on this area. The reinforcement given in the latch and striker mounting area to increase the strength.it is spot welded on the inner panel
Trajectory
The trajectory is created to position the latch and striker. latch system must be able to catch the striker of the door the while closing. Circle is drawn from the hinge axis. The striker follows this path
Hemming
Hemming is a technology used by the automotive industry to join inner and outer closure panels together (hoods, doors, tailgates, etc.). In addition, adhesive bond provides for excellent joining of panels it also reduce vibration. here this design 0.2mm clearance provided for hem glue.
Proper corner relief provided for trouble-free hemming operation.
Draft Analysis
Draft analysis performed to check the designed part is suitable for stamping operation with respect to the tooling direction. We can find out the errors by using this feature. The minimum draft angle is 7.The negative draft is denoted by different colour so we can easily find out the unsuitable areas.
CONCLUSION
The backdoor is designed based on design considerations. Required reinforcement provided on inner panel. The design is checked by using draft analysis feature.