Design of backdoor

DESIGN OF BACKDOOR

OBJECTIVE

• To design the back door of a
• To design an inner panel for the back door.
• To design the necessary reinforcements like Hinge,Gas-stay,Wiper motor, Latch and Striker on basis of engineering standard
• The Inner panel is subjected to Draft Ana lysis for verifying whether it satisfies requirements of Deep Drawing.

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 vehic le 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.

A backdoor is located at the rear end of the car which gives access for the boot space to store luggage,spare wheel etc.These doors cab be operated mannualy or electric powered.In most of the luxuray car is electric powered.Back door is also called as 'Hatch' or 'tailgate','trunk-lid','boot-door' is basically the 5 door in a 4-door car.Its rearmost part of the vehical which gives access to the trunk and has mounts wiper motor,tail lamps,hinges for supporting its weight in opened position,gas stay which help with its opening and keeping it open,radars and cameras etc.

A backdoor is usually made up of 1 inner panel and 2 or 3 outer panels joined together by hemming and spot welding wherever necessary.The material used for backdoor varies as per the price range of the vehicle.Most of the low cost vehicle use steel as it is cheaper and use parts are stamped using moulds.These parts are usually of uniform thickness and reinforcement are added to improve local strength where needed.

MANUFACTURING METHODS

Recently,there have been two approaches to reducing automobile weight. One is by using material lighter than steel and the other is by redesigning the steel structure. Although the former seems very effective,it is very expensive so that it may only be used for an expensive automobile.Therefore,the automobile industry is trying to use steel,which

is not costly and recyclable.Lightweight steel can be achieved by improving the performance of the structure or adopting new manufacturing techniques. One of the efforts is the ULSAB (ultra-light steel auto body) concept.

ULSAB suggests three main weight reduction techniques such as hydro-forming and the tailor welded blank (TWB).

Design Considerations:

• Rear Visibility for safety and functionality
• Support Structures like Hinge and Gasstay/ Power lifter
• Rear Crash regulations
• Boot Space
• Mounts for wiper motor and lights
• Strength criteria
• Draft Analysis

COMPONENTS OF BACKDOOR:-

• Inner panel
• Outter panel upper
• Outter panel lower
• Hinge reinforcement LH
• Hinge reinforcement RH
• Gas stay reinforcement LH
• Gas stay reinforcement RH
• Wiper motor Reinforcement
• Latch reinforcement

OUTER PANEL UPPER AND LOWER:-

Outter panel is the styling surface of the back door.Glass for rear visibility is mounted on the outter panel upper.rear light are also mounted on the outter panel upper.Number plate is mounted on the outter panel lower.Spot welds and other manufacturing process should done only on the inner panel because the outter panel is styling surface which should not have any scratches or welds.Because it affects the style of the car which leads to bad impression on the customer.

INNER PANEL:-

Car backdoor inner panel is made of either steel or aluminium.Most of the luxuary car's inner panel are made of aluminium because of its properties.But the cost of aluminium is high.Cost of aluminium is more as compared to steel.To easily understand,the cost of aluminium for inner panel is higher than the cost of all parts of backdoor together.

Wiper motor,latch reinforcements,hinge reinforcement and gas stay reinforcement are mounted on the inner panel of the backdoor only.The embosses in the inner panel helps stiffening the inner panel and act as a local reinforcement.Another purpose of giving emboss is to distribute impact forces towards hinges.

The inner panel is produced by either casting or through deep drawn method.mostly aluminium panel is only casted,steel inner panel is made by deep drawn process only .If it is deep drawn,then there must be a tooling direction through which that direction the panel is Deep Drawn.

Reinforcements:

• Hinge Reinforcement
• Gas Stay Reinforcement
• Wiper Reinforcement
• Striker Reinforcement

DRAFT ANALYSIS:-

Draft analysis of inner panel is carried out through the tooling direction only.Only the green areas are accepteble and in worst case yellow region are accepteble but the blue and red region are never accepted.

The draft angle for alluminium casted panel is 2 to 3 degree is enough but if its steel then the angle is more than 7 degree.

In this project i considered it as steel and used 7 degree as draft angle and direction is choosen as tooling direction which is the deep drawn direction.

Assembly Images:

Conclusion:

The backdoor is designed by using the given data, in Seimens NX software with a proper guidelines and the result is satisfactory.