Today we will learn about types of springs used in suspension system. Springs which is used in suspension system are helical spring, leaf spring, Torsion bar etc. Who have missed the last post about suspension system, first read that post before reading it
In the last post I have briefly describe the working and
requirement of suspension system. We have also discussed about the component
used in suspension system and we know that the springs are the main component
of suspension system.
ALSO READ: WHAT IS SUSPENSION SYSTEM? HOW IT IS WORKS?
ALSO READ: HOW MANY TYPES OF CLUTCH?
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 Springs used in Suspension System
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
rapidly as the central cavity closes.