Rubber bushings are extruded rubber products that are most commonly used
to reduce or isolate vibration in any machinery that has moving parts. A
bushing can take any shape that will most effectively absorb, reduce,
or isolate vibration in a given machine or set of machinery, though they
tend to be shaped into cylinders and are fitted with metal tubes to
increase their strength.
A rubber bushing functions by gripping a working piece of machinery and reducing its vibration to acceptable levels. Or, bushings can be placed between pieces of machinery to prevent transference of vibration from one piece to the other. They can be used in many industrial settings, but the automotive industry is likely the largest single consumer of rubber bushings. Vehicle suspension systems would not function without bushings; they are used to isolate excessive vibration caused by road bumps and irregularities. All kinds of suspension systems - bicycle, motorcycle and automobile - make use of rubber bushings. Bushings can also be used as engine mounts, which, as opposed to metal engine mounts, eliminates metal-to-metal contact and, as a result, excessive vibration. Like all extruded rubber products, bushings are processed using a rubber extruder.
Extruders are machines that take raw natural or synthetic rubber material, which is also called stock, and collect it in a hopper. The stock is passed through the hopper into a conveyance channel. Most extruders’ conveyance channels use a long screw that moves the stock down the channel as it turns. This pressurizes the stock and, in addition to heat, changes the stock into a semi-liquid state. Once the stock is sufficiently prepared, it is ready to be forced through the die. A die is a tool that is used to turn raw materials into a useful shape. Dies can take any shape, which means that the extrusions they create can take any shape. The near-liquefied stock enters the die and takes its shape. After emerging from the die, the newly extruded rubber is allowed to cool and harden. Depending on how the extrusion is to be used, it may be cut and shipped in its current state, or it may undergo additional processing. Rubber bushings, compared to other extruded rubber products, are subject to very demanding conditions. Natural rubber products tend to degrade when exposed to excessive heat and cold, constant wear and exposure to oils and other kinds of chemicals. For this reason, rubber bushings are often made using synthetic materials in automotive applications.
Rubber Bushings Informational Video