Hood design-Week 2

HOOD DESIGN

Objective:

To design the hood outer panel, inner panel and the necessary reinforcements by following the master section mentioned with the design parameters explained in the videos.And assembly the hood inner panel, outer panel,striker,hinges.

HOOD:

A car hood, also referred to as a bonnet in some other countries, is the hinged cover that rests over the engine of a front-engine vehicle.Its purpose is to provide access to the engine for repair and maintenance. A concealed latch is typically used to hold down the hood.A hood is meant to protect the vehicle's performance parts like the engine or battery.They also provide easy access for car maintenance and repair.Vehicle owners should be aware that hoods are vulnerable to damage.For instance, a hood can damage the hinge ,a device connecting the vehicle body to the hood.It is mainly used to reduce the damage or injury of the pedestrian.The images are given below,

Following parts are using in hood assembly,

1)Hood outer panel

2)hood inner panel

3)Hinge assembly

4)Striker assembly

HOOD OUTER PANEL:

It is the part, which gives luxurious look to the hood or bonnet.Outer & inner panel cannot 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.

HOOD INNER PANEL:

In the inner panel only we can research & implement the safety of pedestrians & as well as the driver. In this panel only we can 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.

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.

STRIKER ASSEMBLY:

Latch & striker is used for locking the hood with the car.It is usually placed on the space provided on the inner panel.

Process involved in designing hood as a sheet metal operations are

1. Blanking
2. Hemming
3. Punch cutting or piercing
4. Embossing
5. Deep drawing

1.BLANKING:

Blanking is a die which is used for manufacturing of sheet material like Bonnet,doors,fenders,roof top in stamping method.It stamping out goes out suitable blank shape, and blanking pressure gets 52KN to 80KN and the outer cover plate is identical with the blank shape of inner cover plate.

2.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.

Conventional die hemming operation is suitable for mass production.In die hemming, the flange is folded over the entire length with a hemming tool.Normally the actual hemming is a result of a forming operation in which the flange is formed with a hemming tool after the drawing & trimming operations have been completed.

While doing the hemming process a relief angle is formed as a product of hemming when attaining at the corner of the sheet.

3.PUNCH CUTTING OR PIERCING:

The outer cover plate after stretch forming and inner cover plate are placed on respectively on corresponding trimming and piercing die,carry out trimming shaping and piercing and shaping die.

4.EMBOSSING:

The sheet metal embossing operation is commonly accomplished with a combination of heat & pressure on the sheet metal, depending on what type of embossing is required.

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

5.DEEP DRAWING:

Deep drawing process is a forming process that occurs under a combination of tensile and compressive conditions. A flat sheet metal blank is formed into a hollow body open on one side or a hollow body is formed into a hollow body with a smaller cross section.

Latch trajectory:

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

Shock flow:

For minimizing the impact of injury when collision with the hood a flow pattern is provided to minimize the impact of injury so that there is minimal damage.This is done for forcing the forces towards outwards with the help of this internal flow structure.

Mastic sealent:

It is used to attach the inner emboss area to the inner side of outer hood at a distance of 80mm

Hemming relief:

It is used to cut some area to avoid the design of outer hood

Conclusion:

The following factors are considered while designing and manufacturing the hood inner and outer panel as per the EuroNCAP safety standards.