Hood design-Week 2

HOOD DESIGN- CHALLANGE

Introduction:-

Hood is main component of a car at the front part. It is used to decorate the car & add luxurious/Sporty look. The shape of the bonnet is made aerodynamic in order to minimize the air effect, hence making it less drag.

DESIGN CONSIDERATION:-

The hood of a car is considered as the frontal BIW enclosure component. Bonnets are designed to reduce air resistance as the air flows around the car. Apart from this, bonnets are also designed to meet several other requirements. They serve a great deal of purpose in protecting the passengers inside the car & the pedestrians in the event of an accident. It also acts as the cover for the engine.

• Following parts are using in hood assembly for this report,

1. Hood outer panel
2. Hood inner panel
3. Hinge assembly
4. Striker assembly

Hood thickness-

• Outer panel thickness= 0.75 mm
• Inner panel thickness= 0.75 mm
• Reinforcement thickness= 1.5 mm

Inner Panel-

• For the inner panel only we can research & implement the safety of pedestrians & as well as the driver too. In this panel we can only attach the reinforcement, embossed, mastic points etc.
• It is an object of the present invention to provide a hood inner panel capable of reduction of a reaction force of the hood inner panel even if a level of deformation of a hood of a vehicle increases, & ensuring a sufficient energy absorption capacity.
• Basically it is an extra cover for protection, resistance to deformation, and strength to the hood.

Outer Panel-

It is also called as cover of inner panel. It is the part, which gives luxurious look to the hood or bonnet. Outer & inner panel can not join by any welding process like spot welding or rivet, which spoil the outer look of a car. The outer panel is generally extracted model from the prototype design. To give a better and simple idea its like a Class A Surface which is a styling surface to look good.

Hinge Assembly-

Hinge is a component that fixes the hood to the fenders of the car. The latch must be fixed perpendicular to the hinge axis so that the hood opens or closes properly. It basically helps for the opening and closing of the hood.

Striker Assembly-

As the name says Latch & striker is used for locking the hood with the car. It is usually placed on the space provided on the inner panel and ensures that the hood is tightly locked in place.

Few process which are included while designing of a hood in sheet metal operations are as followed:-

• Blanking
• Hemming
• Punch cutting or piercing
• Deep drawing
• Embossing

Hemming:-

• Hemming is a sheet metal forming process in which sheets are joined by bending it usually to 180 degree. Automotive body panels & parts such as deck-lids, trunk-lids, doors, hoods & tailgates are formed by hemming processes.
• Roll hemming is carried out incrementally with a hemming roller. An industrial robot guides the hemming roller & forms the flange. Roll hemming operation can also be divided into several pre-hemming & final hemming process steps and the required part is obtained.

The above process shown is known as hemming here the data provided varies according to different size and shape of the hoods, of various cars.

the marked location is the point where a relife is provided for the hemming.

Deep Drawing:-

A deep drawing of sheet metal is performed with a punch and die. The punch is the desired shape of the base of the part, once drawn. The die cavity matches the punch and is a little wider to allow for its passage, as well as clearance. For many calculations, the sheet metal thickness is assumed to remain constant. There are changes in thickness in certain areas, due to force involved.

few example of deep drawing is shown above in the above component which is made for latch and hinge.

Embossing:-

A sheet metal is drawn through the male & female part of the roller dies, producing a pattern or design on the sheet metal. Depending on the roller dies used, different patterns can be produced on the sheet metal.

the marked location are the embossing made. it can be in different size and shapes.

Latch trajectory:-

While opening or closing the hood, the latch must be perfectly aligned to the fixing or striker point. For that, the latches trajectory must be perpendicular to the hinge axis.

Conclusion:-

We have successfully designed a hood that statisfies the design rules and regulation of the hood manufacturing.