This document discusses the key components of an automobile chassis and frame. It describes the different types of chassis, including conventional, semi-forward, and full-forward control chassis. It also outlines the different types of frames used in vehicle construction, such as ladder, backbone, X-frame, platform, and subframes. Additionally, it covers the common materials used to construct frames, including various grades of steel, and discusses other chassis components like bumpers, axles, and their functions.

1. CHASSIS AND
FRAME
1

2. INTRODUCTION
The chassis of an automobile consists of following components suitably mounted the following
◦ Engine and the radiator
◦ Transmission system(clutch, gear box, propeller shaft and axle)
◦ Suspension system
◦ Road wheels
◦ Steering system
◦ Brake system
◦ Fuel tank

4. CLASSIFICATION OF CHASSIS
◦ Conventional control chassis
◦ Semi conventional control chasis
◦ Full Forward control chassis

5. CONVENTIONAL CONTROL CHASSIS
◦ In this type engine is mounted completely in front of the drivers cabin
◦ This type of arrangement avoid full utilization of the space
◦ Un utilised space is more

6. SEMI FORWARD CONTROL CHASIS
◦ Engine is mounted that half of it is in the drivers cabin, where the other half is in front outside the driver cabin

7. FULL FORWARD CONTROL CHASSIS
◦ In which engine is mounted completely inside the driver’s cabin
◦ Maximum utilization of space is achieved in this type of arrangement

8. FRAME
◦ In chassis construction the frame is the basic unit to which various components are attached and body is bolted onto the frame later on.
Function of frame:
- To support the chassis components and the body
- To withstand static and dynamic load without undue deflection or distortion.

9. LOADS ON THE FRAME
• Weight of the vehicle and the passengers
• Vertical loads when the vehicle comes across a bump or hollow
• Load due to road camber, side wind, cornering force while taking a turn, which result in lateral bending of side members
• Load due to wheel impact with road obstacle may cause that particular wheel to remain obstructed while the other wheel tends to move
forward, distorting the frame to parallelogram shape
• Engine torque and braking torque tending to bend the side members in the vertical plane
• Sudden impact loads during collision

10. • FRAME CONSTRUCTION
A,B- Longitudinal
Members
C – Cross Members
D- Dump irons for
bumper bracket and
spring shackle
E- Mountung for the
spring
F – Brackets supporting
the body

11. TYPE OF FRAME
1. Ladder frame
2. Backbone frame
3. X-frame
4. Platform frame
5. Unibody or unit body
6. Sub frame

12. LADDER FRAME
◦ The ladder frame is the simplest and oldest of all design
◦ Also called body-on-frame
◦ It consist of two symmetrical beams and cross members
connecting them
◦ Originally seen on almost all vehicles, the ladder frame was
gradually phased out on cars around the 1940s and is now seen
mainly in trucks The ladder frame do not have the rigidity in
torsion
◦ Also the vehicle’s overall height will be higher due to the floor
pan sitting above the frame instead of inside it

13. BACKBONE FRAME
◦ Backbone frame is a type of an automobile construction frame that is
similar to the body-on-frame design
◦
◦ Instead of a two-dimensional ladder type structure, it consist of a strong
tubular backbone (usually rectangular in cross section) that connects the
front and rear suspension attachment areas
◦
◦ A body is then placed on this structure

14. • To reduce overall hight
and accompany
the transmission system
• Support of the longitudinal
member from cross
member is less , so collision
impact is more

15. PLATFORM FRAME
◦ In this type of frame the passenger compartment floor and often
the luggage compartment floor were permanently attached to the
frame, for extra strength
◦ Floor pieces attached were sheet metal

16. UNIBODY OR UNIT BODY
◦ Also called unitary construction, unitized construction
◦ The frame and body are construcyed as a single unit
◦ Load carrying cappasity is very less
◦ Structural damage may cause when over load

17. SUB FRAME
◦ A sub frame is a structural component of a vehicle
◦ Separate structure with in a larger body-on frame or unit body to carry certain
components, such as the engine, drivetrain, or suspension
◦ The sub frame is bolted or welded to the main frame
◦ When bolted, it is sometimes equipped with rubber bushings or springs to dampen
vibration
◦ The principle purposes of using a sub frame are, to spread high chassis loads over
a wide area of relatively thin sheet metal of a monocoque body shell, and to isolate
vibration and harshness from the rest of the body
◦ For example, in an automobile with its power train contained in a sub frame, forces
generated by the engine and transmission can be damped enough that they will not
disturb passengers
◦ As a natural development from a car with a full chassis, separate front and rear
subframes are used in modern vehicles to reduce the overall weight and cost

18. FRAME SECTION

19. MATERIALS USED
◦ Steels used for pressed frame are mild steel, carbon steel and or aluminium alloys to achieve a more light weight
◦ In case of the seperate chassis, the frame is made up of structural elements called the rails or beams
◦ These are made of steel channel sections , made by folding, rolling, or pressing steel plate

20. BUMPERS
◦ A Bumper is a structure attached to or integrated with the front and rear end of a motor vehicle to absorb impact in a minor collision,
ideally minimizing repair costs
◦ Stiff metal bumpers appeared on automobile as early years
◦ Numerous developments, improvements in materials and technologies as well as greater focus on functionality for protecting vehicle
components and improving safety have changed bumper over the years
◦ Bumpers protect pedestrian from injury
◦ Due to this bumpers are considered as a standard safety equipment
◦ Materials used- polycarbonates, poly propylene, polyamides, polyesters, polyurethanes, and thermoplastic olefins (TPOs)
◦ Many bumpers contain a combination of these different materials
◦ Mix these plastic with glass Fibers or other materials to strength the bumper
◦ This allow them to provide the same impact resistance that metal has, but at a lower cost and with less weight

21. FRONT AXLE

22. ◦ Two type- dead axle and live axle
◦ Axle over which the front wheels are mounted
◦ The part of the weight of the vehicle is transmitted to the wheels through the axle
◦ Made of I-section in center position while the ends are made either circular or elliptical
◦ It takes bending loads and also torque due to braking of the wheel
◦ Provides mountings for sub axle, king pin, steering arm
◦ Transmits power to front axle in case of font wheel drive vehicles
◦ Stub axle is a sub assembly of a front axle beam upon which the road wheel mount
◦ Stub axle is connected to front axle using kingpin

23. TYPES OF STUB AXLES
◦ Elliot
◦ Reversed Elliot
◦ Lamoine
◦ Reversed Lamoine