TYPES OF AUTOMOBILESK.G.Maheswaran

The Automobile bodies are divided in two groups

Body

Passenger Body Commercial body

According to other usage:

• 1. Light vehicle Bodies - cars, jeeps

• 2. Heavy vehicle Bodies – Busses, Lorries• 2. Heavy vehicle Bodies – Busses, Lorries

• 3. Medium vehicle Bodies - Vans, Metadoors

REQUIREMENTS OF BODIES FOR VARIOUS TYPES OF VECHILE

• 1. The body should be light.

• 2. It should have minimum number of components.

• 3. It should provide sufficient space for

passengers and luggage.

• 4. It should withstand vibrations while in motion.

• 5. It should offer minimum resistance to air.

• 6. It should be cheap and easy in manufacturing.

• 7. It should be attractive in shape and colour.

• 8. It should have uniformly distributed load.

• 9. It should have long fatigue life• 9. It should have long fatigue life

• 10.It should provide good vision and ventilation.

CHASSIS FRAME AND BODYTerm initially used to denote the frame parts or Basic Structure of the vehicleA vehicle with out body is called Chassis

A bare ladder frame

System parts mounted on the Chassis frame are

• Power plant, Transmission System, Axles, Wheels and Tyres, Suspension

• Controlling Systems like Braking, Steering etc.

• Electrical system parts

Chassis frame is also called as Carrying Unit

Main components of the Chassis 1.Frame: two long side members riveted together with

the help of number of cross members.

2. Engine or Power plant: It provides the source of power

3. Clutch: It connects and disconnects the power from 3. Clutch: It connects and disconnects the power from the engine flywheel to the transmission system.

4. Gear Box

5.U Joint

6. Propeller Shaft

7. Differential

1. To carry load of the passengers or goods carried

in the body.

2. To support the load of the body, engine, gear box

etc.,

3. To withstand the forces caused due to the sudden

FUNCTIONS OF THE CHASSIS FRAME:

3. To withstand the forces caused due to the sudden braking or acceleration

4. To withstand the stresses caused due to the bad road condition.

5. To withstand centrifugal force while cornering

According to chassis design three types of frames

• 1. Conventional frame

TYPES OF CHASSIS FRAMES

• 2. Integral frame

• 3. Semi-integral frame

• Two long side members and 5 to 6 cross members joined together with the help of rivets and bolts.

Example : This type of frame is used for trucks.

• The frame sections used generally are

Conventional frame

a.Channel Section - Good resistance to bending

b. Tabular Section - Good resistance to Torsion

c. Box Section - Good resistance to both bending and Torsion

• Uses welded steel alloy metal

• C-channel or box frame construction

• Note engine cradle in front and rear axle hump in rear

• Used on large cars and

Full Frame ChassisFull Frame Chassis

• Used on large cars and most all trucks

• Body made in separate unit and bolted to chassis

Pickup truck frame. Notice hat-shaped crossmember in thebackground,c-shape rails andcrossmember in center, and aslight arch over the axle

Pickup truck chassis showing an x-shaped crossmember at the back.

• Used now a days in most of the cars

• No frame and all the assembly units are attached to the body.

• All the functions of the frame carried out by the body itself.

Integral Frame / Frameless construction

body itself.

• Cheaper and due to less weight most economical also.

• Disadvantage is repairing is difficult

ALSO CALLED “UNITISED BODY CONSTRUCTION” OR “MONOCOQUE”

Unitized Body ConstructionUnitized Body Construction

• Called Unibody/ Monocoque• Called Unibody/ Monocoque

• All body and frame parts welded together

• Light weight but strong structurally

• Most cars use this construction

• Advantage: Cheap for mass production. Inherently good crash protection.Space efficient.

• Disadvantage: Impossible for small-volume production.

Unitized Body ConstructionUnitized Body Construction

production.

• Who use it ? Nearly all mass production cars, all current Porsche.

• Half frame is fixed in the front end on which engine gear box and front suspension is mounted.

• It has the advantage when the vehicle is met with

Semi - Integral Frame

• It has the advantage when the vehicle is met with accident the front frame can be taken easily to replace the damaged chassis frame.

• This type of frame is used in FIAT cars and some of the European and American cars

Space Frame Construction

• Newest type of construction Hybrid unibody• Used on race cars first but now used in passenger cars• Many use plastic fenders and body panels

• Advantage: Very strong in any direction. (compare with ladder chassis and monocoque chassis of the same weight)

• Disadvantage: Very complex, costly and time consuming to be built.

• Impossible for robotised production. Besides, it engages

Space Frame Construction

• Impossible for robotised production. Besides, it engages a lot of space, raise the door sill and result in difficult access to the cabin.

• Who use it ? All Ferrari before the 360M, Lamborghini Diablo, Jaguar XJ220, Caterham, TVR etc

Platform chassis types

Body Subframe and Under floor structure

1.Short duration Load - While crossing a broken patch

2.Momentary duration Load - While taking a curve.

3.Impact Loads - Due to the collision of the vehicle.

VARIOUS LOADS ACTING ON THE FRAME

4.Inertia Load - While applying brakes.

5.Static Loads - Loads due to chassis parts.

6.Over Loads - Beyond Design capacity