Design of backdoor

REPORT :

Aim :

To Create backdoor from the given class A surface and perform draft Analysis on the back door.

Back Door :

It is basically located on the back side of the car which is mostly used for boot space and it is opened either manually or it is operated electrically.

In most of the premium cars like fortuner,audi and skoda electircally operated back door is available and in cheaper cars manually operated doors are available.

Fig 1.1

Fig 1.2

Class A Suraface :

Fig 1.3

Sealink Flange : This sealink flange is used for mounting the window has it is seen in a c shape is defined has sealink flange

Fig 1.4

Fig 1.5

The opening is done through the Gas stay provided on both the side mounted on the sealink link falnge

The parts of back door is design

1.Inner Panel

2.Hinge Mounting Brackets

3.Gas Stay bracket

4.Wiper Motor support Stay bracket

5.Latch

6.Latch Reinforcement

7.Hinge Reinforcement

8.Gas Stay Reinforcement

Outer upper panel : It is defined as the area obove the inner panel it covers till the window

Fig 1.6

Outer Lower Panel : It is defined has the area above the inner panel this area is mostly used to mount the license plate

Fig 1.7

Inner Panel : It is the area below the outer upper and outer lower panel this portion is mostly used to do engineering features inside the surface

Fig 1.8

Cable Harness Gap :

Some gap is provided in between the inner panel to give space to the wires and also to give sufficient space to the head light.

In the given below figure the cable harness gap is shown

Fig 1.9

Emboss :

Embossing is a metal forming process for producing raised or sunken designs or relief in sheet material by means of matched male and female roller dies.

Characteristic of a metal embossing process include :

• Its ability to form ductile metals,
• Its use in medium to high production runs,
• The ability to maintain the same metal thickness before and after embossing,
• The ability to produce unlimited patterns, depending on the roll dies, and
• The ability to reproduce product with no variation.

In most machines, the upper roll blocks are stationary, while the bottom roll blocks are movable. The pressure with which the bottom roll is raised is referred to as the tonnage capacity. This figure also depends on the aforementioned parameters.

The Back door design is developed through shaping operation

Materials commonly used in embosses are Aluminium,brass,cold rolled steel,copper,galvinized Steel

For the back door the general load case criteria is

1.Bending Test

2.Torsion Test

3.Abuse Test

4.Dent Test

5.Assembly Load Case

6.Endurance Test

Fig 2.0

1.Bending Test : In this test bending loads are applied and bending load carrying capacity is calculated.

2.Torison test : In this test the twisting loads are applied at the ends and the torsion is calculated

3.Abuse Test : In this test the loads are applied at one end like an over hanging loads,these abuse test is calculated.

4.Dent test : In this test the at what impact whent he loads are sufficient enough to produce the dents these limit is calculated.

5.Assembly Load Case : In this case the final weight of the back door is calculated to reduce the weight has more has possible

6.Endurance : In this test the door is opened repeatdly to closed the fatigue is calculated.

Fig 2.1

Hemming Region :

Hemming is a forming operation in which the edges of the sheet are folded or folded over another part in order to achieve a tight fit. Normally hemming operations are used to connect parts together, to improve the appearance of a part and to reinforce part edges

Fig 2.2

Spot weld is a form of resistance welding operation in which it is used to weld two component together strongly.it involves heat produced by the resistance to an electrical current to join materials together.

Fig 2.3

As shown in the above figure the spot welding is done at high temperature by melting the minimum possible metal in the component.

The same technique is used in welding of the inner components

Fig 2.4

parts of back Door :

Fig 2.5

The Above Figure describes the assembly of the back door along with all the reinforcements of the hinge,wiper and gas stay

Draft Analysis :

It is used to describe wheather the particular component is clearing the manufacturing or not.

If the draft is clearing with respect to the tooling direction then it is shown in green colour.

If the draft is not clearing with respect to the tooling direction then it is shown in red colour.

The Draft angle for Al is 2 to 3 Deg while for the stainless stell is 7 Deg.

Fig 2.6

Draft analysis is performed in the component and majority of the portion of the draft is clearing except in the areas along the length of the surface harness gap can also be draft but by inclining it takes more time and research to be kept in straight but it can be worked out in premium cars

Fig 2.7

Mastic Sealents :

It is a type of liquid sealents that cures in an elastic state that makes it flexible while holding the bond of the surfaces that are attached together it adhers to just about to make material on all purpose type of sealents

1.In the view of keeping the aesthetics of the car the welding and using of bolts are strictly avoided.Mastic is a type of liquid that is used for bonding after sometime the mastic gets hardened the strength of the component will be increased drastically.

Pros :

1.One Positive characteristic of the mastic sealent is that it has very smooth exterior while keeping it rigid from underneath.

2.Mastic Sealents have to be used in outdoors as well of its waterproof quality

3.It functions well in the area of mild vibrations and heat like ducts

CONS :

1.These are not used in the areas where the moment of the component is more,or more in length.

2.It works well in constant pressure but not in constant movement.

Reinforcements :

Vehicle Door reinforcements structure are provided to reduce the impact in collisions.In one emboidment the structure is to include a lower reinforcement configured to mount to a vehicle chassis and upper reinforcement panel welded to the lower reinforcement

Hinge Reinforcements :

Hinge : These are the simple mechanical bearing devices that are used to connect two parts and allow them to rotate relative to each other about fixed axis depending on the type of employed.

Fig 2.8

Material Used in Hinges :

Due to the repeated opening and closing of the hinge more stresses are induced in the hinge that is why the material should able to withstand more stress so therefore stainless steel is used has a material in the hinge.This stainless steel also able to withstand corosssion and rust.The latter is used because the hinges are used in external applications,near the ocean or salt lake

Gas Stay Reinforcement :

Gas stay provides the support to the door while opening and closing and covers that are horizontally hinged

Fig 2.9

Striker Reinforcement :

Fig 3.0

Wiper Motor Reinforcement :

This Wind Shield Wiper Motor is powered by small electric motor usually mounted on the firewall or under the cowl.The motor activates the linkage that moves the wiper arms back and forth

Fig 4.0

Relief :

Fig 4.1

These Reliefs are provided at the corners of the flanges because for hemming the rollers move repetadely to obtain the required shape at the corners thr stresses induced are more to eliminate these stresses the relifs are provided at the corners.

Fig 4.2

Fig 4.3

The Above figures shows the final assembly of all the parts outer upper panel,lower panel and inner panel along with reinforcements

Note :

if any sharp edges are present make sure to fillets the area so that the surface gets strength and will able to clear the draft

Conclusion:

The Back Door design of the car is designed by considering all the parameters and drafting is also done.