Design of backdoor
AIM : To design Backdoor/ of a car and to locate the latch, striker & hinge position in the backdoor for smooth operation.
EXPLANATION :
BACK DOOR / REAR DOOR / TAILGATE / TRUNK
- A vehicle typically has two types of doors: front doors and rear doors. Loosely related are: vehicle hoods and vehicle trunk lids. There are also doors known as a "hatch"
- Back door is placed at the rear end of a car at which the loads can be kept. It is also called a trunk or tailgate.
DESIGN CONSIDERATION TO DESIGN A BACK DOOR:
- 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
- Firstly 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.
INNER PANEL :
FORCE DISTRIBUTION :
When the crash occurs o the car at rear end, the impact force should dissipate to outside. For this we created the embosses in the combination of U/V, undercuts, mastics.
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 AND GAS STAY 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.
UPPER OUTER PANEL:
LOWER OUTER PANEL :
What is HEM ?
- Hems 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, matrial 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.
SIDE RELIEFS :
- Here we added a relief at the curvatures. Because these reliefs will avoid sharpness and it is easy to manufactural.
REINFORCEMENTS:
DRAFT ANALYSIS :
ASSEMBLY IMAGES :
CONCLISION :
The backdoor is designed by using the given data, in Seimens NX software with a proper guidelines and the result is satisfactory.