Design of backdoor

BACK DOOR DESIGN:

Backdoor is the rear closer component of the car. They also trasfers the force made by rear impact. There are many components like gas stay, hinge, viper motor, lactch and sticker, are attached on the backdoor and apporpriate place are provided in it to mount them. In some cases speakers are also mounted on the backdoor. Backdoor can be made as single panal or into two units depending on the design and the manufacturing constrains. Generally the BIW of the backdoor consist of outer panal, inner panal, and reinforcements for the extra components.

There are several configuration invloved on assembling of hinge, gas stay or power spindle to the inner panal depending on the position, place and direction that they are mounted. The correct and suitable combination is determined before getting into the design.

Outer panal:

The outer panal of the back door is attached to the inner panal by hemming process. On hemming several reliefs are made in the area of tight bends and uneven surfaces. Processess like brazing, mastic sealing and spot weldings are also used in some particular places.

Inner panal:

The inner panal design varies depending on the design of the backdoor. The design of the inner panal is responsible for the rear visibility and the boot space. Reducing the depth of the inner panal would increase the rear visiblity as well as the boot space. While designing the sealing flange should have a smooth flow for the proper ans tight closing of the back door. There are many emboss are made in the inner panal for hinge, gasstay, viper motors, etc., to place. Also, to withstand the rear impact many ebosses are made on the inner panal to divert the force outwards to the panal. Also certain holes are punched to facilitate the fixing of the taillamp, viper motor, during assembly. Inner panal also consist of sever hook like structures which help to fix the interior trims. Its is more important consider the tooling direction of the deep drawing process while designing the whole panal.

Reinforcement:

Reinforcements for hinge, gas stay, latch, viper motor are made to enhance the strength of the inner panal at that particular place.

Materials used:

The backdoors inner panal are usually manufactured using steel are aluminium. Both have its advantages and disadvantages. The designing and manufacturing processes of steel and aluminium panals are different to one another.

• Steel inner panal: The steel panal are literally a low cost one. But the manufacturing process involves lots of steps. Reinforcements are made seperatly for the steel panal. Also manufacturing of the steel innerpanal can be done only by deep drawing process. And the panal should be desinged consider the tooling direction and the draft angle.

• Aluminium inner panal: The Aluminium panals are usually provides more strength than steel and made using casting process. As it is casting process we can vary thickness of the panal on specified area required. This eliminates the manufacturing of the reinforcements as seperate parts. Also the draft angle can be reduced futher as it is casted (independent of the tooling direction). All this benifits of the aluminium panal fall on high price of the aluminium panal compared to steel.

TESTING OF BACKDOOR

There are several testes done on the backdoor after and before manufacturing. They are

• Bend test
• Torison test
• Abuse test
• Assembly load test
• Dent test
• Endurance test

DRAFT ANALYSIS: