Springs
The Vehicle frame supports the weight of the engine, the power trains components and the passengers. The frame is supported by the spring.
Springs are fitted between the wheels and the vehicle frame to cushion road shock, to keep the vehicle body levelled up over uneven surfaces, to absorb driving and braking torque loads.
The springs cannot do the complete job by absorbing road shocks. The tyres absorb some of the irregularities in the road.
Types of spring
The various springs may be classified as follows
1) Leaf spring
2) Coil spring
3) Torsion bar
4) Air bags
5) Rubber springs
1) Leaf spring
Leaf springs are made of long, flat strips of spring steel 5 to 12 strips are placed one on the other and held together by means of a center bolt and clamps.
Each strips is called a leaf. There is one leaf which extends the full length of spring and usually contains eyes at both ends for making connection with the frame.
Sometimes in heavier vehicles, the second leaf is also rolled at end to work as a helper for the main leaf.
The other leaves in the spring are assembled with the main leaf by means of center bolt and clamps. Each succeeding leaf is shorter than the preceding one.
The center portion of the spring is connected to the front axle (or) rear axle by "U" bolt. Leaf spring are used in almost all the vehicles particularly in trucks, used both in front and rear axle.
Whenever in car leaf springs are used at rear and in front independent suspension by using coil springs.
1) semi elliptical springs
2) Quarter elliptical springs
3) Three quarters elliptical springs
4) Transverse spring
5) Full elliptical spring
Semi elliptical spring
Semi elliptical springs are usually used in all the vehicles. particularly in trucks, semi elliptical springs are fitted in front and rear axle.
But in cars employing independent suspensions system coil springs are used at front end and leaf springs are used at rear end.
It is cheaper to repair and has long life.
Quarter elliptical spring
This system also called cantilever spring system was mainly used in cars in olden days both at front and rear end.
In this case half elliptical spring is mounted in inverted position with its heavy end bolted to the chassis frame
Torsion bar
It is a steel bar which functions by twisting. The amount of energy stored per unit weight of material is nearly the same as for coil (or) leaf springs.
One end of the torsion bar is fixed to the frame so that it may not turn. on the other end is fixed an arm over which is fitted road wheel.
As the wheel moves up and down, the arm swings like a pump handle and the torsion bar twists and untwists.
Ambassador car is provided with torsion bars at the front independent suspension system.
Advantages
1) Lighter in weight
2) Occupies less space
3) Less maintenance
Disadvantages
1) Does not take braking (or) driving thrust so that additional linkages have to be provided for that purpose.
2) There is no damping effect.
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