A common application is in vehicle suspension systems, where a bushing made of rubber (or, more often, synthetic rubber or polyurethane) separates the faces of two metal objects while allowing a certain amount of movement. This movement allows the suspension parts to move freely, for example, when traveling over a large bump, while minimizing transmission of noise and small vibrations through to the chassis of the vehicle. A Rubber Bushing may also be described as a flexible mounting or antivibration mounting.Based on different embeded material,bushing could be divided into Steel Bushing,Cpper bushing,Aluminium Bushing,and rubber bushing.
These bushings often take the form of an annular cylinder of flexible material inside a metallic casing or outer tube. They might also feature an internal crush tube which protects the bushing from being crushed by the fixings which hold it onto a threaded spigot. Many different types of bushing designs exist. An important difference compared with plain bearings is that the relative motion between the two connected parts is accommodated by strain in the rubber, rather than by shear or friction at the interface. Some rubber bushings, such as the D block for a sway bar, do allow sliding at the interface between one part and the rubber.
Advantages and disadvantages:
(2)Flexibility of rubber also introduces an element of play in the suspension system. This may result in camber, caster, or toe changes in the wheels of the vehicle during high-load conditions (cornering and braking), adversely affecting the vehicle's handling. For this reason, a popular aftermarket performance upgrade is the replacement of rubber suspension bushings with bushings made of more rigid materials, such as polyurethane. Polyurethane bushings are also available for many vehicles with approximately the same characteristics as the manufacturers original bushings, but with greatly increased durability.This is useful on vehicles that have a reputation for wearing out standard rubber bushings, but for which harder bushings with increased harshness of ride are not wanted.
· Anti-roll bar (US Sway bar) links and mountings
· Double wishbone suspension assemblies
· Most high-speed inline internal combustion engines are prone to torsional vibration of their crankshafts; the straight six and straight eight engines being particularly prone to this problem due to their long crankshaft length. Although straight eight engines faded from the marketplace in the 1950s, many straight six engines have and still do feature crankshaft vibration damping utilizing rubber bushes. The 3,442 cc Jaguar XK 6-cylinder engine of 1948 and most subsequent versions of the ubiquitous Jaguar XK engine used a proprietary Metalastik vibration damper to protect their crankshafts from potentially damaging torsional vibrations. To quote William Heynes, "The Metalastik damper consists of a steel plate to which is bonded, through a thick rubber disk, a malleable iron floating weight. Variations of the weight, rubber volume and mix, give these dampers a very wide field over which they can operate."
In fastening, bushings are also used to transfer loads from a fastening to a much larger area in the underlying structure, the object being to reduce the strain on individual fibers within the underlying structure.