Embedded Files
What is Chassis?
Chassis is the under part of a motor vehicle, consisting of the frame (on which the body is mounted) with the wheels and machinery.
Classification of Chassis
According to the fitting of engine the classification of Chassis is as follows:
1. Full forward
2. Semi-forward
3. Bus chassis
4. Engine in front
5.Engine at back
6. Engine at centre
Full forward chassis is one in which the engine is fitted outside the driver cabin or seat like in cars and old Tata-trucks. In this type of arrangement, the driver seat is far from the front wheels and he is not able to see just in front of the vehicle.
In Semi-forward chassis, half portion of the engine is in the driver's cabin and the remaining half is outside the cabin like in TATA 407. It provides better visibility of road to the driver.
In bus chassis, the whole engine is fitted in the driver cabin. It provides an increased floor space in the vehicle. The driver seat is just above the front wheel and he can see the full front road right from the front wheels.
In most of the vehicles, the engine is fitted in front portion of the chassis. The drive is given to the front wheels only in matador vehicles.
The engine may also be fitted at the back portion of the chassis, like in Tata and Ashok Leyland buses. This arrangement does not require long propeller shaft. Gearbox and Differential are combined in one unit.
The engine may also be fitted at the centre of the chassis. This arrangement provides full space of chassis floor for use.
Classification of Chassis Frame
1. Conventional Chassis frame.
2. Integral Chassis frame.
Advantages of Frameless or Integral Frame Chassis
1.Cost is less, as the body floor works as long and cross members.
2.Dead weight of vehicle is less, as body floor works as a chassis and extra cross members are eliminated.
3.Due to elimination of frame, the centre of gravity of the vehicle is lowered, which gives more stability, specially for fast moving vehicles. As stated above, the main floor works as a chassis. As such floor is pressed to form small sections and channels are welded to give it extra strength.
4.A standard Car manufactured in India is equipped with this type of frameless construction.
Disadvantages
The only disadvantage of having an integral frame chassis is, that, in case of an accident, it becomes difficult to repair, set it right and properly align the same.
The frames are made of following steel sections:
Channel Section is used in long member and box section in short members. Tubular section is used now-a-days in three -wheelers, scooters and matadors, pick-ups frames.
Loads on the Chassis frame
The frames should be strong enough to bear load, sudden brakes and accidents. Following loads act on the chassis frame.
1.Weight of the vehicle and the passengers.
2.Vertical loads when the vehicle comes across a bump or hollow.
3.Engine torque.
4.Inertia loads due to brake application.
5.Sudden impact loads during a collision.
6.Loads for longer periods e.g., cornering force while taking a turn.
***End of session -1 of unit 1***
Report abuse