Design of backdoor

                                                                                                                                                                               BACK DOOR

Aim: 

To design a Backdoor of the car on sheet metal using the appropriate design and provided skin data by considering design rules.

Objective: 

To design the backdoor with design methodologies and and provide the emboses,reinforcements in the inner panel and side relief in outer panel to increase the strength.

Backdoor:

• The Back door of a car is a component which hinges at the back of the car to cover the boot space or luggage area, But there are more functions that come with it which has to be considered while making a design of the same like rear visibility criteria and boot space. 
• This part is usually designed keeping the master section of the rear roof rail because of the sealant flange and also various other considerations, as it is also in contact with the side body of the car.
• It has back lights/ Tail lamps and Braking lights which is termed as "Third brake light" mounts on it, rear windshield fixes between inner and outer panel, in some back door spare wheel can be mounted on it, sometimes car registration number plate mounts on it and it gives a complete closed design to the car.

Backdoor images:

              

    

STRIKER:

• The striker assembly is made up of a body constructed from a pair of individually formed rigid members which are fixedly secured to each other.
• The rigid members each including a mounting flange adapted to mount the assembly to the door pillar or jamb of an automobile.

Striker image:                                                                              

 HINGE:

• Hinges is the assembly of components connected to the door and body of the vehicle, linked to each other and capable of rotating around the same axis.
• Conventional system consists of two hinges for each door, an upper hinge and a lower hinge.

Hinge Images:

                          

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

Procedure:

• First we have to check if there are any surface irregularities in the skin data, If irregularies are there, then repair if by using a bridge curve and Through curve mesh and sew it.
• Then we create a sealing flange.
• Generally with the help of master sketch, we will design the panel with appropriate dimensions.
• But here there is no master sketch,we designed by assumption.

             

Sealing Flange: 

• It is that section of the inner panel which enables the backdoor to sit over the rear body side of the car.
• Its design is important as it decides how a backdoor is mounted on the rear body side of the car and also restricts any external matter to enter inside the vehicle.
• Here the sealing flange is created by maintaining a gap between inner panel to the sealing flange.

Tooling Direction-

• The back door is going to be manufactured by deep drawing process.
• In Deep Drawing process have a tool which is core and Die.
• The core part follows the single Straight path the inclination angle of the core is known as a tooling direction.
• The tooling direction/axis is created so, that the Manufacturing team take the reference of this tooling axis and manufacture the part accordingly.                                           

Inner Panel:

              

MASTICS:

• In automobile manufacturing, adhesives are used for joining seats, spoilers, tailgates, side skirts, bumpers, headlights, dashboards, and others.

Mastic region:

• The mastic points are defined on the backdoor inner panel where the backdoorcan easily deform. They help the backdoor outer panel to come back to its original shape after it gets deformed.Mastic sealants are elastic compound that behaves like the rubber.
• The gap between the inner panel and the outer panel over the embosses is filled with mastic sealents at certained specified places, this helps to reducing vibrations and overall NVH ( Noise, Vibration, Harshness).
• Then, the sheet will bend with the help of another die to make the flange in "L" shape.
• Thus, the flange will have somehow same design and the length will completely depend on the Cut-out, if we need more length of flange, then we need to cut more sheet.
  
  

Emboses:

• With the distinctive cross-section, embosses are created. The embosses are used to increase the strength of the backdoor. While designing we should keep in mind that it should not be over strength. So we prefer to design big embosses rather than small embosses. These embosses are used to disipate the forces sideways.

       

Hinge Emboses

• The backdoor is a swinging commodity, which swings with the help of hinges.
• This can be done by tentatively positioning the hinges and on the hinge axis, we take a center point.
• Again we take another center point(approx) on the latch hole.
• Taking these two points as a reference we draw a circle.
• This circle is the striker trajectory and it has to be perpendicular.
• This can be achieved by moving the hinge axis back and forth or by rotating the latch area.

To create hinge mounting emboss

• A plane was taken because mounting area should be flat or should not have any radius of curvature.
• A sketch was drawn on that plane.
• The emboss command was used to make the hinge emboss feature by using plane as an end cap of hinge emboss.
• And holes were created for the nut and bolts for assembly of hinge.

      

 Gas Stay Embose:

        

Wiper Embose:

striker:

Outer Upper and lower Panel:

    

 Hemming:

• Hemms are folds to the edge of a part to create a rounded, safe edge.
• Hems may be open, flat, or tear-dropped, and tolerances depend on the hem’s radius, material thickness, and features near the hem.
• The process of creating hems is called hemming.
• Hems are created by bending a flange of your part back on itself.
• This increases the strength of the hemmed edge and also gets id of any sharp edges.

         

corner Reliefs:

• Here we added a relief at the curvatures. Because these reliefs will avoid sharpness and it is easy to manufactural.

            

Reinforcements:

To describe the strengthening of the association between an unconditioned and a conditioned stimulus that results when the two are presented together.

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

    

    

Draft Analysis:

Tooling Direction 

Assembly Images:

     

     

Conclusion:

• The backdoor is designed by using the given data and the result is satisfactory.