20-12-2012, 03:17 PM
AUTOMOBILE CHASSIS
AUTOMOBILE CHASSIS.docx (Size: 2.11 MB / Downloads: 42)
INTRODUCTION
Chassis is a French term and was initially used to denote the frame or main structure of a vehicle. It is now extensively used to denote the complete vehicle except the body for the heavy vehicle having a separate body. The chassis contain all the major units necessary to propel the vehicle, direct its motion, stop it, and allow it to run smoothly over uneven surfaces. It is the main mounting for all the components including the body. It is also known as carrying unit.
The chassis include following components as shown in fig: 1.1 .Frame, .Front suspension, Steering mechanism, Radiator, Engine, clutch, gearbox, Propeller shaft, Rear spring, Road wheels, Differential, half shaft, universal joints, Brakes end braking system, Storage battery, Silencer, Shock absorbers, fuel tank, petrol and hydraulics pipe cables and some means of mounting these components.
LAYOUT OF CHASSIS AND ITS MAIN COMPONENTS:
The following main components of the Chassis are
1. Frame: it is made up of long two members called 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 the engine fly
wheel to the transmission system.
4. Gear Box
5. U Joint
6. Propeller Shaft
7. Differential
As said before, the car needs to withstand various forces, so which are these forces:
Lateral G (cornering speed)
Longitudinal G (determined by acceleration and braking
Load (passengers or goods)
Road irregularities (bumps, surfaces and cambers)
Perimeter Frame
Similar to a ladder frame, but the middle sections of the frame rails sit outboard of the front and rear rails just behind the rocker panels/sill panels. This was done to allow for a lower floor pan, and therefore lower overall vehicle in passenger cars. This was the prevalent design for cars in the United States, but not in the rest of the world, until the uni-body gained popularity and is still used on US full frame cars. It allowed for annual model changes introduced in the 1950s to increase sales, but without costly structural changes.
In addition to a lowered roof, the perimeter frame allows for more comfortable lower seating positions and offers better safety in the event of a side impact. However, the reason this design isn't used on all vehicles is that it lacks stiffness, because the transition areas from front to center and center to rear reduce beam and torsional resistance, hence the use of torque boxes, and soft suspension settings.