SUSPENSION SYSTEM
Definition:
- The set of mechanical parts, springs, and dampers known as a suspension system attach the
wheels to the chassis.
- It manages the vehicle’s handling and braking for safety, and keeping passengers
comfortable from bumps, vibrations, and other factors.
Functions:
- Maintain correct vehicle ride height
- Reduce the effect of shock forces
- Maintain correct wheel alignment
- Support vehicle weight
- Keep the tires in contact with the road
- Control the vehicle's direction of travel
Components of Suspension System:
Springs – it balances out the shocks from the road surface.
Dampers- utilized to lessen springs' natural tendency to oscillate, which improves riding
comfort.
Stabilizer- prevents the vehicle from swaying to one side.
Linkage System – it controls the longitudinal and lateral movements of wheels
Types of Suspension System:
Independent Suspension
- the suspension is set up so that the wheels on the left and right sides of the vehicle can
move up and down vertically independently while traveling over an uneven surface.
- The fundamental benefit of independent suspension is that it takes up less space, is easier to
steer, is lighter, and so on.
Example: Double Wishbone Suspension and MacPherson Strut
Dependent Suspension
- A stiff linkage connects the two wheels of the same axle in Dependent Suspension.
- A force operating on one wheel will have an effect on the other. Primarily used in trucks
Example: Solid Axle
Semi-Independent Suspension
- the wheels move relative to one another in the same way as they do in independent
suspension, but the position of one wheel has an effect on the position of the other. This is
accomplished by the use of twisted suspension parts.
Example: Twisted Beam
TYPES OF SUSPENSION SPRINGS
1. Leaf Spring
-
consists of a number of leaves, made of steel plates, of increasing lengths from the center.
- The main leaf is the longer one having bent ends, called the spring eyes. The spring eye is
connected to the frame by a shackle. The centre portion of the spring is connected to the
front axle by U-bolt.
Types of Leaf Spring
a. Semi-elliptical Springs
- are fitted in front and rear axles.
- cheaper and require less repairing. They increase the range of spring action and last for a
long time.
- usually used in all the vehicle, particularly in trucks.
b. Quarter-elliptical Spring
- used in old small cars, like Chrysler cars. This type of spring consists only a quarter portion of
the full elliptical spring and fitted with the frame by the bolt.
c. Three quarter elliptical Spring
- the combination of semi-elliptical and quarter elliptical springs. This types of springs was
used in old cars.
d. Transverse Spring
- One end of the spring in joined with chassis frame by shackle, and the other end with the
axle. It is also fixed with frame by the bolts at the centre.
e. Full-elliptical Spring
-
consists of two semi-elliptical springs joined together oppositely. This type of spring was used in
old cars. They do not maintain correct axle alignment.
d. Platform Type Spring
- They are fitted with chassis frame by shackle at one side and the other side is fitted with an
inverted semi-elliptical spring.
2. Helper Spring
- It is fitted with the main springs particularly on the rear axle of the truck to carry the heavy
load. The ends of the helper spring touch the brackets fitted on the frame when the truck is
heavily loaded.
3. Coil Springs
- Coil springs are made of spring steel. These are described with the independent
suspension system.
4. Torsion Spring
- used in an independent suspension system. Torsion suspension spring has a rod
which acting under the torsion by taking shear stresses.
5. Air Bags
- are used in foreign cars. Air suspension, hydraulic suspension and hydrogen gas
suspension systems are also used in foreign vehicles.
6. Rubber Springs
- are used in suspension because it saves greater energy per unit weight than the steel.
