Design of backdoor

BACK DOOR DESIGN

Back door is one of the major BIW closure of an automotive , it provides an opening and closing of the car luggage area which used to storing items inside a car and its also uccupy the spare wheels some times. opening and closing is carried out by gas stays in normal cars and for luxury cars electrical systems is used. the motion is here constructing by using hinges which is attached to the car body. back door also called tail gate.

PARTS OF BACK DOOR

• outer panel
• outer panel lower
• inner panel
• hinge reinforcement
• gas stay reinforcement
• wiper motor reinforcement
• latch and striker reinforcement

TYPE OF BACK DOORS

There are three types of back doors

top mounted

In this project we are desinging a top mounted back door

side mounted

bottom mounted

DESIGN CONSIDERATIONS OF BACK DOOR

• Visibility Criteria
• Force Dissipation
• Latch and Stricker Positions
• Hinge Position
• Gas Stay Position
• Material Selection
• Space Availability
• Hemming and Relief Areas

visibility criteria

rear visibility criteria is one of the major design factor in automotive design. whenever we designing a back door, the sealing flange should not restrict the rear view of driver. so we must bother about the emboss thickness of the sealing flange.

force dissipation

safety is the main consideration of the design of the BIW components. we need reduce the impact of collision to the inside of the car for the passenger safety. so we need to dissipate the force of impact whenever a collision happens. for that we need to create V or Y shape embosses on the inner panel to dissipate the force into side of the car and reduce the impact to the inside.

latch and striker postion

the opening and closing must be proper, inorder to ensure that the centre point of the latch and stricker has to to be at the same point and the trajectory has to be tangent to the open close circle that is drawn. only if the centre points and the tangent line are perfect the opening and closing of the back door is smooth and clear. or else the Hinge positions, Gas stay positions and Latch and Stricker Positions has to be altered to meet the change.

hemming and relief areas

hemming is a sheet metal process where the edges of the sheet metal is bended onto itself to provide a joint. here we use hemming for joining inner panel and outer panel. after hemming we use a sealant coating to provide a air tight fit and for good appearance. in corner areas we must provide a hemming allowance to enhance the proper bending of the sheets.

COMPONENTS OF BACK DOOR

OUTER PANEL

Outer panel is the aesthetic surface of the back door of the car. edges of the outer panel consist of hemm used to joint with the inner panel. rear wind sheild area is provide on the top side of the back door. most of the times outer panel desingned to be two parts, there outer panel lower and upper. the rear lamp area is also provided on the outer panel. sometimes the number plate is also mounter on the bak door so we need to provide a sufficient area for the number plate lamp.

INNER PANEL

Inner panel consist of sealing flange area, wind sheild area, wiper motor area, hinge area and latch and striker area. sealant flange is provide to create a air and water tight conact between weather strip and inner panel. weather strip is a rubber component which is mounted on the rear edge of the car body boot area to provide a air and water tight joint.

we must create embosses on the inner panel to dissipate the force whenever the rear collision happens. also provide a rear wiper motor mounting nearest to the wind shield area. this mounting is also attached to the outer panel by using mastic sealing for provide sufficient joining between outer panel and inner panel.

REINFORCEMENTS

reinforcements is providing for enhancing better strength to the body where the load application is more. Types of reinforcements in back door are,

• hinge reinforcements
• gas stay reinforcements
• wiper motor reinforcements
• latch and striker reinforcements

DRAFT ANALYSIS

Draft should be provide to the sheet metal for the easiness of the stamping thats why can improve the tool life and reduce the cost of tooling.