Design of backdoor

TITLE - TO DESIGN THE BACK DOOR OF THE CAR USING NX CAD.

OBJECTIVE – The main objective of this report is to design the back door of the car that includes the hinge and gas stay reinfocements, and positioning of latch and striker, wiper motor and hemming respectively according to the desired considerations.

INTRODUCTION

Back door is also known as tail gate that is a door at the back of a truck or car, that is hinged at the top or bottom so that it opens, which covers the boot space of the automobile which gives access to the luggage area. A hinge that allows the boot lid to be raised , while devices such as springs or gas cylinders hold it up in the open position. It is generally, the openning and closing of the door is co-ordinated by latch and striker position and gas stay position that is mounted on the body and back door of the car. Hinges, gasstay and latch and striker reinforcement plays a major role in smooth opening and closing of the back door of the vehicle.

TYPES OF BACK DOOR

There are three types of back door based on the position of hinge axis, they are

• Top mounted

• Side mounted

• Bottom mounted

In this model, we are going to use top mounted back door.

DESIGN METHODOLOGY

DESIGN CONSIDERATIONS

• Visibility criteria
• Force distribution
• Hinge axis positioning
• Gas stay mounting
• Latch and striker positioning
• Space availability
• Selection of material
• Hemming
• Relief

These all considerations plays a major role, their position(gas stay and latch & striker) is inter-related to each other in opening and closing of the back door. Make sure that these considerations should meet with design.

• From the given skin data few surface are repaired and the given skin is divided into two parts because of complexity(joining) named as outer panel upper and outer panel lower.

OUTER PANEL

It is the styling part of the back door and has provision for the tail lamps, rear fog lamp and also the liscence plate mounting.

OUTER PANEL UPPER

OUTER PANEL LOWER

INNER PANEL

The inner panel is a component which is used for strenghening the door assembly and it is one of the most important components on which all accessoried are mounted like hinges, windshield area, hinges, gas stay, wiper motor, latch and striker mountings. This method is integration method in which part is stamped out of a simgle blank, this reduces the overall cost of the product.

EMBOSS

Embosses are created on the inner panel by stamping technique, it is a carve, mould, or stamp a design on (a surface or object) so that it stands out in relief. These are mainly created to dissipate the force outwards when collision occurs, that prevents the injuries to the people inside the car.

FORCE DISSIPATION

The force is dissipated away when collision happens, these are very important for the back door and even for bonnet, side doors, etc.

MASTICS

It is used to join two different parts, it prevents from Noise, Vibration, and Hardness issues. Usually 4 to 5 mm of space is given in between the two parts to give mastic sealants.

REINFORCEMENTS

These are generally used to increase the strength of the mountings to prevent it from NVH Issue. Overall it improves the stability of the back door. The reinforcements used in this are

• Hinge reinforcement
• Gas stay reinforcement
• Wiper reinforcement
• Latch and striker reinforcement

HINGE REINFORCEMENT

These are the reinforcements that are useful for opening and closing of the back door, not only the back door for any doors the hinges can be seen. It is a movable joint or mechanism on which a door, gate, or lid swings as it opens and closes or which connects linked objects. It typically allows for a limited angle of rotation.

GAS STAY REINFORCEMENT

The pupose of this is to lift up the tail gate and they are of two types

• Manual system
• Power lift system

Manual system

It is operated directly by man manually and it is mostly used in India.

Power lift system

It is operated automatically using a sensor. It can be seen mostly in high end vehicles.

WIPER MOTOR REINFORCEMENT

The car wiper motor is the component that powers the windshield wipers. As it spins, a mechanism built to it rotates a worm gear, arm and, finally, the windshield or windscreen wiper blades. The wiper blades then rid the windscreen of water, snow, dust, or any other debris that may affect visibility when driving.

LATCH AND STRIKER REINFORCEMENT

The latch is the small metal bolt that you will see sticking out of the back of the door when the door is open.The door strike is fastened, usually by screws, onto the frame of a doorway, and it is carefully aligned with the lockset in order to give the latch a place to sink into when the door closes. The latch & striker is designed by taking the hinge axis as a reference. With this reference point taking as center, circle is drawn passing through the latch that should be perpendicular to the latch.

HEMMING

It is a forming process in which the edges of the sheet are folded over another part. Hemming is a sheet metal forming process in which sheets are joined by bending it to 180°. Automotive body panels and automotive parts such as deck-lids, trunk-lids, doors, hoods and tailgates are formed by hemming process. In this process, usually a sheet is bent with the help of inner sheet in three different stages.

CORNER RELIEF

Corner Relief is provided to one or more corners of a sheet metal part. When you add relief, sheet metal sections are removed from the model. You can apply corner relief automatically to all corners or manually to individual sets of corners. Relief helps to control sheet metal material behavior and to prevent unwanted deformation during unbend operations.

DRAFT ANALYSIS

Draft Angle is an important requirement in the die casting process. It is described as an angle or amount of slope that is incorporated into a wall of a die casting mold making the opening of the die cavity wider than its base. To avoid high pressure in castings, the inside corners must be protected with fillets.

BACK DOOR

FRONT VIEW

SIDE VIEW

TOP VIEW

ISOMETRIC VIEW

CONCLUSION

Hence the design of back door is done by using NX CAD as per the industrial standards and manufacturing techniques.