Design of backdoor

Back Door Design:

Aim: To Design a Back Door of car which can distributes the forces equally while undergoes in to deformation.

Objective: The Main objective of this Project report is to design and create a back door, which can protect the passenger when the external forces acted on it.

To create a mount where gas stays and other electrically operated utilities can be placed to reduce the human effort.

Back Door:

Back door is generally located at the back side of the car, which provide the access to store luggage and other necessary elements during travel.

Back door of the cars can be manual and electrically operated, for these electrically operated back doors we need gas stay and other elements to reduced the human effort, these types of facilities are provided in the luxury cars.

Types:

Types of back doors are totally depended on the position and placement of the door on the car.

• Top Mounted Door
• Side Mounted Door
• Bottom Door

Top Mounted Door:

These types of doors are used in Compact SUV and other utility vehicles, and commonly scene in hatch-back vehicles. This type of Top Mounted Door allows us to store luggage, these types of mounted tailgates provided greater rear visibility compared to side mounted or backdoor which have center pillar in it.

Side Mounted Door:

As we see side mounted door are the one which are commonly scene in the VAN’S and other trucks. These Side mounted doors or barn doors are a lot easier compare to top mounted doors. These doors are generally attached to the side rail of the van and it is a lengthy component 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.

Bottom Mounted Door:

In this type the door is attached to the bottom rail/ chassis of the car, and this type of mounted door is way different compared with other type of back doors, because in this type the back door is divided in to two where the both parts are attached to the top rail of the roof and another one is bottom rail/ chassis of the car.

Gas Stay type:

Push on a gas spring and you force the piston rod and piston into the cylinder and this compresses the gas. Stop pressing and let go and the pressure of the gas pushes the piston back out again. So far, that sounds just like a bicycle pump—but it's working in a different way. Unlike with a bicycle pump, gas inside the cylinder can actually flow through or around the piston from one side to the other as it moves back and forward. Exactly how this happens varies from one design of gas spring to another; usually the piston has one or more holes or valves in it. Now if the piston can move through the gas, you might think it isn't compressing the gas at all. But don't forget that the whole cylinder is completely sealed. When the piston rod is inside the cylinder, it's taking up room that the gas previously occupied. In other words, when a gas spring is fully pushed in, you've compressed the gas inside by an amount equal to the volume of the piston rod. If the piston rod occupies virtually the whole cylinder, you can see that the gas is getting compressed quite substantially.

Powered Lift System:

Which working mechanism is as similar as gas stay type but the main difference is it does not need any human effort to open the lid and to close the lid, it actually works under the guidance/ the commands given to the sensors which are helpful in the working of lift system, some time it needs less amount of human effort compared to the gas stay mechanism.

Manufacturing Procedure:

Draft angle: Usually draft angle is provided on the part, as well as the core and cavity, in order to reduce the wear and tear of the product while ejecting from the mould.

Draft analysis is northing but the analyzing the draft angle provided on the part as well as the core and cavity of the injection mould by the Engineer

Draft angle allows ejector to simple push, to pop out the part from the mould

There are certain standards should be followed to provide the draft angle on the parts, core and cavity.

• Usually, the nominal draft angle 3deg is provided on the part
• Providing the nominal draft angle is easy and very economical.

Draft angle is depending on the material which is being used to prepare the product.

Ex: Textured parts required the more draft angle than the usual

Deep Drawing Process:

Deep drawing is a process of converting metal sheet into cylindrical or box shaped structure with or without changing its length and thickness. Many cylindrical parts like metal can, pots, container for food and beverages, kitchen sinks, automobile fuel tank etc. are deep drawing product.

Before discussing its working process, first we should learn about main part used in drawing process. These parts are as follow.

The blank is placed over an open circular die with the help of blank holder. The blank holder provides a necessary force to hold the blank. The punch which is attached with a mechanical or hydraulic press moves downward and provide a necessary drawing force at blank. This force tends to deform metal sheet and forces it into the die cavity and convert it into a cup shape structure.  If this force is high it causes elongation of cup wall to thin and if excessive, it causes tearing of sheet. So the punch force should remain a certain limit to avoid tearing during operation.

Hemming: Hemming is one of the forming processes which is used to join outer and inner panel without effecting look of the Hood.

Roller hemming:

Robot hemming is utilized for the manufacture of Low to medium production volumes. It uses a standard industrial robot integrated with a roller hemming head to provide a flexible method for forming closures. The flange of the outer panel is bent over the inner panel in progressive steps, by means of a roller-hemming head.

One advantage of this process is that it can use the robot-controlled hemming head to hem several different components within a single cell. Another is that minor changes or fluctuations in panel-hemming conditions can be quickly and cost-effectively accommodated. If equipped with a tool-changing system, the robot could serve a variety of additional functions within the same assembly cell, such as operating dispensing equipment for adhesives and sealants, or carrying out panel manipulations, using a gripper unit.

Latch trajectory: Latch trajectory tells us about the fixing position and movement of the hood to the latch.

In this above shown figure the latch trajectory of hood is defined.

Design Procedure:

The Class A Surface is given to create the back door outer and inner panels.

First, we need to trim the surface in to two halves’ by selecting Trim option. Later we need to offset the Trimmed portion of the hood in order to create inner panel.

The two offset regions are joined by using Through curve option available in NX CAD. The same operations were repeated until the required given master gets fulfilled.

Reinforcement:

Reinforcements are used to provide more strength to the mounts which are provided to attach some electrical components.

Draft analysis:

As explained above draft analysis is done on the back door using NX-Cad which tells us that the draft angle provided during designing is sufficient to provide the component or not.

Conclusion:

Designing and analyzing a back door is done successfully using NX-CAD 3D-Modeling Software.