SUSPENSION

WHAT IS IT.?

• A SYSTEM OF SPRINGS OF SPRINGS AND SHOCK ABSORBERS THAT CONNECT WHEELS AND AXLES TO CHASSIS OF VEHICLE.

WHAT DOES IT DO.?

• CARRY WEIGHT OF VEHICLE(SPRUNG MASS).• PROVIDES STABILITY.• MINIMIZES FRICTION BETWEEN ROADS AND TYRES.• PROVIDES GOOD HANDLING.• COMFORTS PASSENGERS.• ALLOWS RAPID CORNERING WITHOUT EXTREME BODY

ROLL.

Types:Dependent suspensions: both right and left wheel attached to the same solid axle . Vertical movement of one wheel causes slight tilt of other wheel.Independent suspensions: allows one wheel to move up and down with minimal effect of other.

Basic parts:

Control Arm:- movable lever that fastens the steering knuckle to the vehicle’s.

Steering knuckle:-provides a spindle or bearing support for the wheel hub , bearings and wheel assembly.

Basic parts:Ball joints:-swivel joints that allow control arm and steering knuckle to move up and down and side to side.

Springs:-supports the weight of the vehicle , permits the control arm and wheel to move up and down.

Basic parts:

Shock absorbers or dampers:- keeps the suspension from continuing to bounce after spring compression and extension.

Control arm bushing:- sleeves that allow the control arm to swing up and down on the frame.

Suspension types:

• McPhersons strut• Leaf spring• Double wishbone suspension• Trailing arm suspension• Transverse leaf spring• Beam axle• Push/pull rod suspension

McPhersons strut:

• It is the most widely used front suspension system in cars.

• Consists of a strut-type spring and shock absorber combo, which pivots on a ball joint on the single, lower arm. At the top end there is a needle roller bearing. •  The strut itself is the load-

bearing member in this assembly.

McPhersons strut:• The steering gear is either

connected directly to the lower shock absorber housing, or to an arm from the front or back of the spindle.

• When you steer, it physically twists the strut and shock absorber housing (and consequently the spring) to turn the wheel.

Leaf spring:

• It is the most common rear suspension for heavy vehicles dead simple and cheap to build.• The drive axle is clamped to the leaf springs and the

shock absorbers normally bolt directly to the axle.• The ends of the leaf springs are attached directly to

the chassis, as are the tops of the shock absorbers. • Simple, not particularly elegant, but cheap.

Leaf spring:

DOUBLE WISHBONE:

Type I: -The wheel spindles are supported by an upper and lower 'A' shaped arm. In this type, the lower arm carries most of the load. -Because of its geometry the up and down movement causes side to side movement called scrub.

DOUBLE WISHBONE:

Type II:- The only difference is that the spring/shock combo is moved from between the arms to above the upper arm. Upper arm carries load. The lower arm acts as control arm.-Isn't so popular in cars as it takes up a lot room.

DOUBLE WISHBONE:Type III:(Multilink suspension)-Instead of solid upper and lower wishbones, each 'arm' of the wishbone is a separate item. These are joined at the top and bottom of the spindle thus forming the wishbone shape.

-Because all the various joints make the suspension almost infinitely adjustable

Trailing arm suspension:

• a shaped suspension arm is joined at the front to the chassis, allowing the rear to swing up and down. The difference is that instead of the arms sticking out from the side of the chassis, they travel back parallel to it. • Takes up more space, but it doesn't

suffer from the side-to-side scrubbing problem of double wishbone systems.

Transverse leaf spring:• It combines independent double wishbone suspension

with a leaf spring . It involves one leaf spring mounted across the vehicle, connected at each end to the lower wishbone. • The center of the spring is connected to the front sub

frame in the middle of the car . Two shock absorbers, mounted one to each side on the lower wishbones.• Not commonly used.

Transverse leaf spring:

Beam axle:

• The beam runs across under the car with the wheels attached to either end of it.• Spring / shock units or struts

are bolted to either end and seat up into suspension wells in the car body or chassis.

Beam axle:

• The beam has two integral trailing arms built in instead of the separate control arms required by the solid-axle coil-spring system. • This is a diagonal bar which

runs from one end the beam to a point either just in front of the opposite control arm or sometimes diagonally up to the top of the opposite spring mount .

Other types of suspensions: