Design of backdoor
OBJECTIVE :
1) From the given classA surface, develop a back door using appropreiate design methodoliges..
2) The objective of this project is to design the back door of a car with a inner pannel, outer pannel and the reinforcement for the Hinges, Gas stay, Wiper motor, and the latch by following the standards.
3) The inner panel must be a subjected to draft analysis for verifying whether its satisfies The deep darwing requirements for the requirements for the tooling direction has created in the design.
SOFWARE USED:
SIEMENS NX CAD
INTRODUCTION :
The Back door of car is the rear most part of the vechicle, which gives acess to the trunk space of the vechicle. The rear door also support the reinforcements and added the weight of wiper motor, Gas stay, tail limp, Latch and striker.
The backdoor / tailgate is one of the closure commodities in BIW sheet metal design. The backdoor has a lot of components in it and its designed to incoroperate them easily.. its affect the rear visbility and the lugagge area.
The material used for the door manufacturing depends on a budget and performance of the vechicle. Mostly Aluminium and steel used where as the low budget vechicles use steel which makes manufacturing process easy and the cost-efficient since it follows the stamping of the mould.
Major Parts and Reinforcments :
The backdoor consists of the following components :
1. Back door outer panel (upper)
2. Back door outer panel (lower)
3. Back door inner panel
4. Hing reinforcement (RH& LH)
5. Gas stay reinforcements (LH&RH)
6. Latch and striker Reinforcemnt
7. Wiper motor reinforcement
TAILGATE :
Tailgate is the door at the back of the truck or car, that is the hinged at the bottom so that it open downwards.
DESIGN INTENT :
The intent of the project is to design an body in white back door of the vechicle considering those engineering standards and the manufacturing requirements which satisfies the deep drawing process.
DESIGN CONSIDERATION OF BACKDOOR :
1. Functional requirements of hinge and gas stay
2. Rear visiblity criteria
3. Luggage space
4. Crash analysis
5. Bend test, dent test, torsion test and Endurance test
6.Gap and flushness requirements..
DESIGN OF BACKDOOR OUTER PANEL :
The outer panel is the class A surface of a back door. other components of back door is designed with referance to the outer panel and it acts as outer cover also deals with aesthetic of the car.
In this design outer panel designed into two parts.
1. Outer upper panel
2. Outer lower panel
Outer upper panel :
1. The outer upper panel is extracted from the Class A surface
2. The panel is altred for a required design with the surface tools Nx Cad
3. The thickness provided for outer panel is 0.75mm
4. Hemming is also provided with the corner relief
Outer Lower panel :
1. The outer lower panel is extracted from the ClassA surface
2. The panel is altred for the required design with surface tools Nx Cad
3. The thickness provided for outer panel is 0.75mm
4. Hemming is also provided with the corner relif
Lower and upper panel :
Tooling direction :
1. Before starting to design a inner panel of back door and the tooling direction for deep drawing purpose should created
2. Then the styling surface needs to checked and analyzed since it might have irregularities, hence it is must fixed first
3. Then the back door was design by the top down approach
Design of back door inner panel :
1. The inner panel extracted from the styling surface
2. The panel is altred for required design
3. The thickness provided for outer panel is 0.75mm
After creating tooling direction. The design of inner of inner panel would being were we will first develop a effective sealing Flange by checking all the boundries and by a following the shape of inner panel design. By creating a multiple flanges and by using the surface modeling techniquces the concept design of inner panel has created
1. After the concept of inner panel is developed, Then the child components like hinges, latch, gas stay locations and there reinforcements must be designed. which complete the over all design of the component ( back door )
2. The embosses were created so that if the vechicle has undergoes the crash then the force dissapates over which reduces the damage transfered to a trunk space
MASTIC SEALENT :
The mastic sealent is used to fix inner panel and the outer panel together which is increases the NVH factor and stiffness of that back door
Hinge, gas stay and wiper motor :
The hinge emboss which was been created using the datum plane and emboss feature in NX. It was also design in the way that emboss should have a flat surface for the assembling the hinges by using it
The gas stay emboss which was created using surface of the connecting flange
The wiper motor emboss was created using the surface of the flange
LATCH AND STRICKER EMBOSS :
The latch and striker which is designed by the creating a trajectory that follow the opening and closing of a back door with respect to the hinge axis
STRIKER POSSITION :
The position of hinge should be at perpendicular to the latch, when the latch and striker meets, The circle is drawn from the center of the hinge axis to find the path of the striker and positioned perpendicular to a path
HEMMING :
Hemming and seamming are the two similar metal working process in which sheet metal edge is rolled over on its self. Hemming is the process in which the edge rolled flush to itself
1. The outer panel as designed as two parts named has outer panel upper and lower.
2. After designing the outer panel the hemming has created by offsetting the surface with those help of blend and the swept surface
3. The Two separate outer panels will joined...
CORNER RELIEF :
During the hemming process, when giving the corner reliefs helps to control the sheet metal material behaviour and to prevented the unwanted deformation during the process of unbending operation and also its helps to reduce the no of pasess in hemming..
DESIGINING THE REINFORCEMENT :
The thickness is provided for reinforcement is 1.5mm
1. Hing reinforcement
2. Gas stay reinforcement
3. wipermotor reinforcement
4. latch reinforcement
All reinforcements has been created by using the same method first the linked body has created separately for each with a help of an extract geometry and then the required portion has trimmed out and them thickend..
Hing reinforcement :
Hinges enabling the closing and the opening of the tail gate. one end of hinge is fixed on a back door and the other end on the roof, on both sides. Hinges has be placed on out side or in side of the back door.
The hing reinforcements are added to compensate for the weak regions, due to the acting load over them.
Gas stay reinforcement :
Gas stay is a device uses for supporting the back door in it's opening position. Gasstay will work individually and its engaged in to the support position automatically as the backdoor opens. one end of the gas stay is fixed on a back door and the other end on a body side or on the backdoor stationary.
Embossing has provided at the gas stay in mounting area to compensate for the weakness and to improve strength.
Wiper Motor reinforcement :
Wiper motor reinforcement has created to mount the wipermotor assembly.
Latch and the striker reinforcement:
The latch and striker form the locking mechanism of the backdoor with the car. Due to the constant opening , closing and the over slamming of a backdoor, there is stress developed in a latch and striker area. To compensate for same, reinforcements are added in that area...
DRAFT ANALYSIS :
1 .The draft analysis will performed for a tooling direction created first and checked that the model is suitable for the manufacturing.
2. Then to get a complete an green portion for the necessary changes to the draft angle of embosses has been carried out by a optimizing the model.
3. The draft Analysis command also enables us to detect that the part drafted can be easily removed or not
4. This type of analysis is performed based on the colour range, identifying zones on the analyze element,
where the deviation from the draft direction on any point, corresponds to specified values ,..
VIEWS OF DESIGNED DOOR :
CONCLUSION :
Thus the body in white Back door of the car was designed by following the engineering standards and also the deep drawing requirements is also satisfied by using NX cad