Design of backdoor

Aim

     To create a back door using the given styling surface by following the design standards and to provide necessary reinforcements and embosses in crucial regions of the inner panel of the back door.

 DESIGN OF BACK DOOR

     The rear door of an automobile is a crucial component of its design, acting as more than just an entrance and exit. In addition to serving a practical purpose, the rear door greatly enhances an automobile's overall appearance and structural soundness. Its designs range from sedans to SUVs, meeting a wide range of requirements and tastes. Apart from granting entry to the vehicle's rear compartment for either passengers or goods, the rear door is equipped with vital safety elements including child locks and strengthened crash structures that guarantee the protection of the occupants in case of an accident. Ensuring security is of utmost importance, as evidenced by advanced locking mechanisms and alarm systems that prevent unapproved access.Furthermore, power operation and integrated windows are common convenience features seen on contemporary back doors, which improve usage and comfort. Selecting a material that balances strength, weight, and corrosion resistance is essential. The back door, which embodies both innovation and practicality in equal measure, is a tribute to the sophisticated balance of form, function, and safety inherent in vehicle design, whether it is swinging open or lifting upward.

Types of back door

     Swing-Out Doors: Among the most common styles, swing-out doors are often referred to as hinged doors. On side hinges, they swing outward from the body of the car.  certain SUVs often have these doors. They have a large opening for simple access and departure, and the hinge is usually located on the back border of the door.

    Hatchback Doors: Hatchback doors, often found in compact cars, wagons, and some SUVs, are a single piece incorporating both the rear window and the door itself. They hinge at the top or bottom and open upward, providing access to the cargo area. Hatchbacks are known for their versatility, offering ample storage space and the ability to accommodate bulky items.

     Tailgate Doors: Often found on trucks, SUVs and other larger cars, tailboard doors can be used as both rear doors and access points for goods. They provide a platform for loading and unloading cargo since they hinge at the bottom and open downward. Tailboard doors may also have an independent glass part that opens separately to provide easy access to smaller objects.

     Sliding Doors: Minivans and certain commercial vehicles are known for having sliding doors. They provide a large opening for passengers and freight as they glide horizontally along tracks inserted into the body of the vehicle. Sliding doors offer simple access without requiring additional clearing space to swing open, making them particularly helpful in busy and congested parking areas.

Tpes based on working mechanism

     Power-Operated Doors: Power-operated doors can be opened and closed electronically with the push of a button. They often incorporate sensors to detect obstacles and prevent accidents. Power-operated doors enhance convenience, particularly for individuals with limited mobility or when carrying heavy loads.

     Gas stay doors: Gas stays, also known as gas struts or gas springs, are integral components commonly utilized in the design of vehicle rear doors, particularly in hatchbacks and tailgates. Operating on the principle of compressed gas, typically nitrogen, these mechanisms facilitate controlled and smooth movement during the opening and closing of the door. When the rear door is opened, the gas stay's compressed gas exerts force on a piston rod, assisting in lifting the door and maintaining it in the open position. This not only reduces the effort required to lift heavier doors but also ensures that the door stays securely open.

Manufacturing process of a back door inner panel

Stamping process

     Stamping is a primary method for forming the basic shape of the door inner panel. Large presses apply force to a metal sheet, usually steel or aluminum, to shape it into the desired contour. This process creates the general shape of the inner panel, including features such as curves, bends, and flanges.

 

Deep drawing process

 

 

 

 

   

 

    For particular inner panel sections that need more depth, like sunken portions for handles, armrests, or speaker grilles, deep drawing can also be used. In deep drawing, a metal blank is progressively stretched and formed to fit the die's shape by being dragged into a die cavity with a punch.

 

 

 

 

 

 

Back door components

 

 

     

 

     

 

             1.Outer upper panel.

 

 

 

     

 

      2.Outer lower panel.

 

 

     

 

     

 

             3.Inner panel.

 

 

 

   

 

       4.Wiper motor Reinforcement.

 

 

 

     

 

     5.Hinge reinforcements.

 

 

 

     

 

     6.Gas stay reinforcements.

 

 

 

     

 

     7.Striker reinforcement.

 

 

 

Outer panel 

 

 

 

 

   

 

 

      The outer rear door panel functions as the outward face of the car's rear entrance, representing both aesthetic appeal and solid construction. This panel, which is usually made of stamped steel or aluminium, is the outermost layer of the door and serves to support and shield its internal machinery. It is carefully painted or finished to blend in with the car's general external design, protecting the metal from rust and improving its aesthetic appeal. The exterior panel's precise design frequently includes body lines, curves, and contours that complement the car's overall style. Functional features like a door handle recess are incorporated into the design to ensure simple accessibility without sacrificing the door's elegant form.Furthermore, the panel's surface incorporates holes for key cylinders and openings for door mirrors. Its edges may be adorned with weatherstripping, trim pieces, and insignia, which provide flair and functionality. Together, these parts provide a unified outer panel that improves the back door's overall functionality and visual appeal by fusing form and function.The thickness of outer panel is 0.75 mm.

 

 

 

 

 

 

 

 

Inner panel

 

 

 

 

   

 

      A rear door's inner panel is a crucial part that supports the door structurally and contains a number of functions that enhance its usability and security. Other components are installed on the inner panel, which acts as a foundation. It contains essential components such as the wiper motor , gas stay, and hinge reinforcements. Additionally, it has a door latch and lock system that guarantees a safe closure and restricted access to the inside of the car. Furthermore, the inside panel frequently has speakers and power window regulator supplies, incorporating contemporary amenities elegantly into the door's appearance. It might also have reinforcements and impact-absorbing materials to improve occupant safety in the case of an accident.Furthermore, it may feature trim panels and upholstery to enhance the interior aesthetics and provide a cohesive look with the rest of the vehicle's cabin. Overall, the inner panel of a back door plays a crucial role in the door's functionality, structural integrity, and overall comfort and convenience for passengers. The thickness of the inner panel is 0.75 mm. The inner panel is manufactured by stamping and deep drawing process.

 

 

 

Wiper motor reinforcements

 

 

          

In order to support the installation and operation of the rear windscreen wiper motor, this reinforcement is a structural element that is integrated into the inner panel of the back door.The wiper motor reinforcement, which is usually composed of robust materials like steel or aluminium, offers a stable mounting location for the motor assembly. This guarantees that the motor is firmly fixed to the door and that it can bear the forces generated during use, including the wiper arm's movement and the windshield's resistance.The thickness of the reinforcement is 1.5mm.

 

 

 

Striker reinforcement

 

 

 

      A back door's striker reinforcement is a structural element intended to fortify the region where the door latch or striker bolt contacts the door frame during closure. This reinforcement is especially crucial to guaranteeing the door assembly's lifetime, safety, and robustness.The striker reinforcement is included into the inner panel of the rear door and is usually constructed of high-strength steel or another durable material. It lowers the possibility of the door frame deteriorating or deforming over time by more equally distributing the pressures produced during door closure across the surrounding structure. It also reduces the level of NVH.The thickness of the reinforcement is 1.5mm.

Hinge reinforcements

 

 

 

     

 

     A back door's hinge reinforcement is a structural element intended to give the hinge mounting locations on the door frame more strength and support. Usually, these reinforcements are built into the rear door's inner panel, around the hinge attachment points.The hinge reinforcement is also essential to guaranteeing that the door operates and aligns correctly. It contributes to the stability and integrity of the door assembly by giving the hinges a strong anchor point, preventing sagging, misalignment, or excessive movement that might compromise the door's operation or safety.The thickness of the reinforcement is 1.5mm.

 

 

Gas stay reinforcements

 

 

 

        The rear door's gas stay reinforcement is a structural support element made especially to withstand the stresses applied by gas stays or gas struts, which help open and hold the back door in place. The rear door's inner panel usually incorporates these reinforcements.It aids in uniformly distributing the load applied by the gas struts throughout the door's surrounding construction. This helps keep the door panel from bending or breaking over time, especially when big or heavy doors are involved.

The thickness of the reinforcement is 1.5mm.

 

 

 

 

   

 

 

Draft analysis of Inner panel

 

 

 

       From the draft analysis it is seen that the inner panel has green colour in all its regioin which means that it has minimum of 7 degrees draft angle in all of its region. The miinimum draft angle of 7 degrees should be followed so that during the manufacturing process like deep drawing and stamping the tool wear rate will be less. If the tool wear rate is less mannufactring cost will be low during the mass production of inner panel.

Green - 7 degrees and above

 

 

Yellow - 0 to 7 degrees

 

 

Blue    - 0 to -7 degrees

 

 

 

Red     - -7 degrees and above

 

 

 

Hemming process

 

 

 

   

 A vital stage in the production of automobiles is the hemming process, which ensures strength, security, and good looks in the rear door. Hemming is the process of folding a metal sheet's edge over onto itself to form a smooth, double-layered seam. The door outer upper and lower panels are folded at the edges , so that the inner panel can be attached to the outer panel wthout the use welding process, this process is called hemming. Welding process will ruin the aesthetic look of outer panel so hemming is preferred in joining the outer and inner panel.After hemming process corner relief are given to reduce the stres concerntartion on all edges and corners of the outer panel.

 

 

 

 

Conclusion

 

 

      Thus from the given Class A surface, the back door is designed by following all the design rules and norms and reinforcemnts and embosses are created in all crucial regions. The minimum draft angle of 7 degree is maintained in all the places to support the manufacturing process like deep drawing and stamping.

 

 

 

 

 

 

 

THE GOOGLE DRIVE LINK FOR DESIGN OF BACK DOOR - https://drive.google.com/file/d/1n8-UcsOV0faSV99aUVtXHtoNmB5c9tQ0/view?usp=sharing