Hood design-Week 2

                                                                 HOOD DESIGN

Objective: - Design hood outer panel, inner panel and reinforcements with the given outer hood skin, master section and design parameters. And create assembly design as output along with Hinge and Sticker data.

Introduction:-

Hood is main component of a car at the front portion. It is used to decorate the car & add luxurious look. The shape of the bonnet is made aerodynamic in order to minimize the air effect.

A typical hood assembly consist of hood outer panel, inner panel, latch and striker, hinge, hood stay. Hood stay is an apparatus for supporting the engine hood of a motor vehicle in its open position. The purpose of opening the engine hood is for inspecting engine room, replenishing cooling water and engine oil, changing parts and making repairs etc.

The hood or bonnet is the hinged cover over the engine of motor vehicles. Hoods can open to allow access to the engine compartment (or trunk on rear-engine and some mid-engine vehicles) for maintenance and repair. In design perspective hood should meet some specific conditions like pedestrian safety, hood head zone for the lock striker, force distribution when subjected to frontal collision (occupant safety), manufacturability etc.

Hood are typically made out of the same materials as the rest of the bodywork. This may include steel and aluminum. Deep drawing, hemming, blanking and piercing are the common sheet metal operations that are used in manufacturing hoods in automotive industries.

Hood 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.

Design parameters:-

Hood Thickness Information

    Outer Panel Thickness = 0.75mm

    Inner Panel Thickness = 0.75mm

    Reinforcement Thickness = 1.5mm

Following parts are using in hood assembly for this report,

1. Hood outer panel
2. Hood inner panel
3. Hinge assembly (Qty - 2 )
4. Striker assembly

Master Section:-

 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.

 

 

Outer Panel-

We can also call it 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.

 

 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.

 

 

 The process involved in designing hood as a sheet metal operations is

• 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.
• Coventional die hemming 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.

 

 

Deep Drawing-

• Deep drawing is a manufacturing process that is used extensively in the forming of sheet metal into a cup or box-like structures. Pots & pans for cooking, containers, sinks, automobile parts, such as panel & gas tanks, are among a few of the items manufactured by sheet metal 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

 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.
• A sheet metal is drawn through the male & female 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.

 

 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.

 

 

Draft Analysis :-

 

 

 Final Output -Hood Assembly :-