Automotive suspension is designed for the elastic connection between the wheels and the vehicle body, and for the pothole vibration damping. Suspension should provide comfort driving (smooth ride), traffic safety and cornering stability. Suspension characteristics depend on the parameters and the interaction of individual components, the type and the stiffness of the elastic elements, stabilizers, arms, dampers, engine mounts, wheelbase, track, and especially tires.
Car suspension includes guiding and elastic elements, damping elements (shock absorbers), anti-roll bars, the wheel supports and fixing elements.
The guiding elements provide a predetermined trajectory of movement of the wheels relative to the vehicle body. As guiding elements various arms and rods are used: control, tracking, and so forth.
The elastic elements perceive and convey the reaction forces to the vehicle body when wheels run upon the bumps in the road. Rubber, pneumatic or steel elastic elements are used in suspension. Springs, leaf springs and torsions represent steel elastic elements.
Rubber elastic elements – Bushings, bushings, pads, suspension-moving limiters and reduce energy suspension. The main objective of the rubber elastic elements is to isolate the body from the noise and vibrations generated while driving. And provide a connection between suspension components and car body, wheel support.
Shock absorber is designed for the damping of the vehicle body’s vibration, resulting from the pothole affects. The work of shock absorber is based on creating of resistance force occurring at a certain speed of the piston and the flow of fluid within the damper, through the calibrated openings (valves).
Anti-roll bar or sway bar or stabilizer – a rod of circular cross-section, with supports attached to the body, connecting the arms of the opposite wheels on one axle. The stabilizer is used to reduce body roll and improve vehicle stability when cornering. The anti-roll bar may be mounted on the front and rear axle.
In general, all suspensions are divided into two types, with a fundamentally different nature of the work – dependent and independent.
In the dependent suspension, wheels of one axle are rigidly connected to each other, and moving of one wheel in the axle affects the other. Dependent suspension was continuously improved and is used in one form or another still. Modern versions of such suspension concede the independent suspension a number of parameters, but at the same time have a number of important advantages. The first is that in contrast to the independent suspension, track of the wheel is not changed; wheels are always parallel to each other. In case of no-driving axle rear wheels may have a little fail of alignment, but on a relatively flat surfaces are always in the best position perpendicular to the surface of the road, regardless of the suspension decline and body roll. Dependent suspension due to its simplicity is high reliable.
In the independent suspension wheels do not have a rigid connection on axle, and moving one of them does not affect either the second one or makes a small effect. In addition, such settings as the track, the wheels alignment, and in some types the wheelbase are being changed while the compression and rebound of suspension, sometimes quite considerably. The design of independent suspension allows to reduce unsprung weight and improve the smoothness of the driving. In modern cars independent suspension is used as the basic design of the front and rear suspensions.