SUSPENSION SYSTEM AND ITS TYPE

Use of spring in Suspension System:

We know that any system used in vehicle to reduce road shocks and vibration known as suspension system. Springs, shock absorber torsion
bar etc. are components of suspension system.  Due to irregularity of roads when a vehicle runs, it feels lot of vibration due to road irregularity and engine vibration. So if the car is perfectly rigid this vibration transmitted into whole body of car which cause damage of its body parts and also it is uncomfortable for the passengers too.

So the Suspension Springs are used to separate the Wheel of the vehicle to the body so when the vehicle feel those vibration it transfer to the spring and the spring start oscillating without transmitting this vibration to the vehicle body. So these springs are the main component of suspension systems.

Today we used various types of vehicle according to load capacity and luxuriousness. So there are different types of spring and suspension systems used in those different vehicles.

Types of Suspension springs

1. Leaf Spring:

Semi elliptic leaf springs are almost used in commercial vehicles. It is also used in cars for rear suspension. The spring consist of a number of leaves called blades. The blades vary in length and connected together as shown in the figure. These springs based on the theory of beam of uniform strength.

This spring is mounted on the axle by the U bolt and the one end of spring is mounted on the frame and other is connected with a shackle which allow to change in length between eye of spring when the vehicle come across projection of road and upward movement of wheel.

When there is wide range of loading on vehicle helper spring is also provided with the leaf spring which increase the weight loading capacity of vehicle. These springs are made by the Chrome-Vanadium Steel, Silico-Manganese Steel or Carbon Steel as per requirement. These spring are noisey and does not used where luxuriousness is necessary.

2. Helical Spring or Coil Spring:

We all have seen coil spring in our daily routine many times. The helical spring used is suspension system is same as we see. It is mainly used in the independent suspension. It is also used in the conventional rigid axle suspension as they can be well accommodated in restricted spaces. The energy stored per unit volume is almost double in the case of coil spring than the leaf springs.

These spring do not have noise problems but they does not take torque reaction and side thrust for which alternative arrangement have to be provided.

3. Torsion Bar:

It is simply a rod which acting under the torsion and taking shear stresses. It is often used with independent suspension. One end of the bar is fixed to the frame and the other end is fixed to the end of the wheel arm and supported in the bearing. The other end of the wheel arm is connected to the wheel hub. When the wheel strikes a bump it start vibrating up and down, thus torque on the torsion bar which acts as a springs.

4. Rubber Springs:

The rubber springs are also used in suspension because it store greater energy per unit weight than the steel. So it is more compact than other springs. It has also excellent vibration damping property. One more advantage of using rubber is that it is not suddenly fail like steel so there is less risk.

The various types of rubber springs used.

Compression springs:

This type of spring is still being used because it is reliable, simple in construction, can resist occasional overload of large magnitude, and have large damping effect.

Compression shear spring:

In this type of spring the load is carried partly by shear and partly by compression.

Steel reinforced spring:

It consist steel helical spring bonded in a rubber body. The steel spring carrying only 20% of load.

Progressive spring:

It has initially an exceedingly small rate which rises rapi9dly as the central cavity closes.