Design of backdoor

BACK DOOR:

aim:

        To design a back door of the car on sheet metal using the apporopriatedesign and provided skin data by considered design rules.

objective:

         to design the backdoor with design methodologies and provide the embooses,reinforcement in the inner panel and side relief in outer panel to increase the strength.

what is back door ?

 

          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.

           Back Door is also referred as 'Hatch' or 'Tailgate' or 'Trunk-lid' or 'Boot-door'. Its the rearmost part of the vehicle which gives access to the trunk and has mounts for tail lamps, hinges, wiper motor, gas stay etc...

function of the back door:

           It protects the occupants and luggage from getting damaged.

           It houses assembly of tail lamps, wiper motor and other components.

           It serves as entry and exit point for luggage/passengers.

           It houses windshield glass which helps in rear visibility.

           Parking sensors, rear view camera are mounted on it.

types of back door :

         * top mounted

         * side mounted

         * bottom mounted

top mounted:

         These type of back doors are used in a station wagon, pickup truck and some other sports utility vehicles. Today’s modern cars use top mounted tailgating systems which are both powered and also gas stay supported. These tailgates provide greater rear visibility compared to other types.

  

side mounted:

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.

  

bottom mounted:

               Bottom type or split type backdoor system is used in estate type cars, pickup trucks and some luxury SUVs. These are most convenient type of backdoor in which the bottom split is used as a support or even as a table for the touring people.

  

types of mechanism in rear door:

gas stay:

           gas stay types 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. 

  

powerlift:

            power lift is the another method of the lifting mechanism in which operated in electrically automatic syatem of the car. it will operated  in using of electric supply for automatically open close in the use of touch the button. 

  

wiper motor:

              wiper is used to wipe off the dust and water from the rear windscreen of the vehicle. this will operated automatically using of electric supply.

 

latch and striker:

Door strikers are hooks or bolts that latch up the doors on a vehicle. The striker is designed to create a tight fit between the door and the seal on the cab. The striker plate is made of hardened metal that prevents wear when the door is open and shut many times each day. 

design of backdoor:

design cinsideration:

• Rear visibility
• Boot space & accessibility
• Sealing Flange
• Support structures like hinges and gas stays.
• Mounts for wiper motor, tail lamps and other wiring loops
• Rear crash regulations
• Joining techniques such as hemming, spot welding etc.
• Gap and flush requirements.                                 

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

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. 

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.

 

 

 

Hinge Reinforcement:

            hinge is the open close compnent of the back door. this surface is wave geomentryed in the inner surface requeried faces.

 

 

Gas Stay Reinforcement:

         This gas stay is the component in which using back doofr open and close of the operation. 

 

 

wiper motor reinforcement:

 

latch and striker reinforcement:

 

 

assembly of back door and components:

           inner panel  condains all the reinforcement.

 

 

then the outer panel os ofseted for 2 mm for the hemming purpose.

 

outer panel having 2 surface. outer panel upper and outer panel lower these are the two panels will joinetd for the spot welding. spot welding is nothing but, joining two surface in using of electrically heating and applying the pressure in the both surface. then the welding process is starting in the heating of two elements will be welded in that touching spot.

 

 

 

 

draft analysis:

 

conclusion:

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