The document discusses frames and chassis in vehicles. It defines a chassis as consisting of the engine, powertrain, brakes, steering, and wheels mounted on a frame. There are three main types of frames: conventional frames with a separate load-bearing frame and body; semi-integral frames with stiffer mountings that share some load with the frame; and integral or unitized frames where the underbody and body shell are welded into a single load-bearing unit without a separate frame. The document also discusses different frame sections and loads acting on vehicle frames.

1. FRAME AND CHASSIS
Chassis is a French term which is now denotes
the whole vehicle except body in case of heavy
vehicles. In case of light vehicles of mono
construction, it denotes the whole vehicle except
additional fittings in the body.
“Chassis consists of engine, power train, brakes,
steering system and wheels mounted on a frame”.

3. Front-Engine Front Wheel Drive

4. Front-Engine Rear-Wheel-Drive

5. Rear-Engine Rear-Wheel-Drive

6. Four Wheel Drive

7. FRAME
• The frame is the main part of the chassis on which
remaining parts of chassis are mounted. The frame
should be extremely rigid and strong so that it can
withstand shocks, twists, stresses and vibrations to
which it is subjected while vehicle is moving on road. It
is also called underbody.
• The frame is supported on the wheels and tyre
assemblies. The frame is narrow in the front for
providing short turning radius to front wheels. It
widens out at the rear side to provide larger space in
the body

8. TYPES OF FRAME
• Conventional frame,
• (b) Semi-integral frame, and
• (c) Integral frame (or unit frame).

9. Conventional Frame
• It is non-load carrying frame. The loads of the
vehicle are transferred to the suspensions by the
frame. This suspension in the main skeleton of
the vehicle which is supported on the axles
through springs. The body is made of flexible
material like wood and isolated frame by
inserting rubber mountings in between. The
frame is made of channel section or tubular
section of box section.
• Example : This type of frame is used for trucks.

10. • It has two long side members and 5 to 6 cross members joined together
with the help of rivets and bolts. The frame sections are used generally.
• a. Channel Section - Good resistance to bending
• b. Tabular Section - Good resistance to Torsion
• c. Box Section- Good resistance to both bending and Torsion

11. Semi-integral Frame
• In this case the rubber mountings used in
conventional frame between frame and
suspension are replaced by more stiff
mountings. Because of this some of the
vehicle load is shared by the frame also. This
type of frame is heavier in construction.
• Example : Popular in European and American
car.

12. • Semi - Integral Frame: In some vehicles 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 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.

13. Integral Frame or Frame-less
Construction
• In this type of construction, there is no frame.
It is also called unitized frame-body
construction. In this case, the body shell and
underbody are welded into single unit. The
underbody is made of floor plates and channel
and box sections welded into single unit. This
assembly replaces the frame. This decreases
the overall weight compared to conventional
separate frame and body construction.

14. • Integral Frame: This frame is used now a days
in most of the cars. There is no frame and all
the assembly units are attached to the body.
All the functions of the frame carried out by
the body itself. Due to elimination of long
frame it is cheaper and due to less weight
most economical also. Only disadvantage is
repairing is difficult.
•

15. TYPES OF SECTIONS USED IN FRAMES
• Channel section,
• (b) Tubular section, and
• (c) Box section

16. • Various loads acting on the frame are
• 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.
• 4. Inertia Load - While applying brakes.
• 5. Static Loads - Loads due to chassis parts.
• 6. Over Loads - Beyond Design capacity.

18. STATE THE DIFFERENT BODIES
USED IN AUTOMOBILES
• The Automobile bodies are divided in two
groups
• Body
1. Passenger Body 2. Commercial body