Suspension System: Rear suspension types & components

Suspension System:

Rigid axle leaf spring suspension

The front of the leaf spring is attached to the chassis at the rigid spring hanger. This spring eye is bushed with either rubber bushes or, in the case of heavy vehicles, steel bushes.
The axle housing is rigid between each road wheel. This means that any deflection to one side is transmitted to the other side.

The swinging shackle allows for suspension movement by allowing the spring to extend or reduce in length, as the vehicle moves over uneven ground.
The top of the shock absorber is attached to the chassis, and to the spring pad at the bottom. It is a direct-acting shock absorber.
The U-bolts attach the axle housing to the leaf spring. They have a clamping force that helps to keep the leaf spring together. Leaf springs are usually made of tempered steel. They hold the axle in position, both laterally and longitudinally.
The leaf spring is usually made up of a number of leaves of different length. The top, or longest leaf, is normally referred to as the main leaf.

Rigid axle coil spring suspension

The shock absorber is attached to the axle at the bottom and to the chassis at the top. It is a direct-acting, telescopic-type shock absorber.
The coil spring is mounted between the axle housing and the vehicle body.
In this example of the Watts Link suspension, the lower trailing arm assists in maintaining the longitudinal position of the housing.
In addition, the drive torque is transmitted through this arm to the vehicle body.
The axle housing is rigid between each road wheel. This means that any deflection to one side is transmitted to the other side. These control rods are the additional parts for the ‘Watts Link’. Their function is to assist in stabilizing the vehicle against lateral movements.
In other coil-spring rear suspension designs, this is achieved with an angled panhard rod.
The upper trailing arm provides the additional control for the longitudinal movement. These trailing arms are mounted in rubber bushes.

Independent type suspension

In this application the shock absorber is attached to the chassis at the top, and to the axle at the bottom. It is a direct-acting, telescopic-type shock absorber.
The coil spring is mounted between the axle housing and the vehicle body.
The lower trailing arm assists in maintaining the longitudinal and lateral position of the housing.
In addition, the drive torque is transmitted through this arm to the vehicle body.
The trailing arm is attached to the chassis at a rigid cross-member pivot point. This pivot point is fitted with rubber bushes.
The fixing frame is attached to the vehicle body. The frame supports the differential unit and its housing.
The drive shaft transmits the drive from the differential unit to the road wheels. These wheels are able to move or pivot independently.

Rigid non-drive suspension

The lower trailing arm assists in maintaining the longitudinal position of the housing.
A ‘U’ shaped axle beam has a torsion bar mounted inside it.
This type of suspension is known as a “Dead Axle”. It does not transmit any drive.
The panhard rods function is to assist in stabilizing the vehicle from lateral movements.
The struts have an upper mounting point in the suspension tower.
This is a non-steerable strut, and as such, does not require an upper bearing.