Mechanical bushings are removable cylinders or donut-shaped items, designed as lining, insulation or sleeves to reduce friction on a machine’s moving parts. They’re also used to ensure a tighter fit to constrict or restrict the movements of mechanical parts. Bushings ensure that the machine parts run more smoothly, its parts fit together properly and prevents the machine from wearing out easily.
Bushings are also used to transfer weight from individual fibers to larger areas underneath the structure, in that way reducing stress on the smaller structures and fibers. The way you install bushings can affect how your machine works, whether it be simple or complicated
Bushings are also installed with flexible material like rubber or polyurethane to minimize noise, vibration and wearing. Rubber bushings are used to connect the moving arms and pivot points to the chassis and parts of the suspension.
In electronics, bushings are plastic rings that are designed to slide or screw onto conduits and connectors to protect the insulated cables that are pulled within them. They also insure that the stability of the cables are not compromised before, during and after installation.
In skateboards, bushings can be softer or harder. Hard bushings provide more stability while softer bushings provide more flexibility.
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.
Types of Bushings
There are many kinds of bushings, usually depending on what kind of machine or device you’re using it on. Generally, though, they are categorized as such:
Threaded Insert. This is an insert with with a threaded hole which allows assembly by screw or threaded bolt without the need of using a separate nut and washer. Threaded inserts are fitted into sheet materials via a tool that operates on the same principle as riveting.
Plain Bearing. The most common kind of bushing, and in fact, is also another generic term for it. Plain bearings are typically made of two parts: a rotating component that passes through a stationary component. The materials are typically a steel shaft and a bronze bushing itself, the bushing bearing the brunt of the wear. Dry plain bearings can be also made out of graphite and ceramic. Plain bearings are light, inexpensive and relatively simple, making it easy to repair or replace. An example of a plain bearing are rotary plain bearings which can be a shaft running within the hole. Another example of a plain bearing is a linear bearing, which can be a pair of flat surfaces to allow motion, the ones used in drawers to allow it to slide and support its weight.
Plain bearings can hold depending on operating conditions, load, surface speed, clearance within bearing and lubricant, if any. A drawback to their design is that when operating in dry or boundary conditions, they may prove to wear out easier.
There are also plain bearings that employ built-in lubrication by means of having porous journals that hold the lubricants. There are also plain bearings that have full-film, which means that there is no contact at all between the surfaces of the shaft and the bearing. There are also fluid bearings which are bearings the support the load on a thin layer of liquid or gas.
Solid Polymer. Unlike typical plain bearings, solid polymer plain bearings do not rely on lubrication, which makes simple plain bearings even simpler. This also means that solid polymers’ wear time will be easier to predict, they are easier to produce, lighter, and less prone to corrosion. With solid polymer, bushings are produced with a very thin layer of polymer coating applied on the inside.
Electrical Bushing. Electronic devices require bushings that will insulate high-voltage conductors. Bushings made for electronics are typically made from fired porcelain and glazed with a semi-conducted coating to help lessen electrical inside the bushing. Electrical bushings also have a sub-type called capacitor bushings because of the required low value capacitors between the conductor and the bushing’s wall to lessen the electrical stress. Capacitor bushings are usually used for higher-voltage types of electronics.
Rubber Bushing. These are usually used for suspension systems that separates metallic parts while allowing a fixed degree of movement. An advantage of using rubber over solid bearing systems are that they have less noise less vibrations and no lubrication. The disadvantage of using rubber bushing is that they can break down easily when exposed to oil and extreme temperatures of heat and cold.
Polyurethane Bushing. An alternative for rubber bushing, polyurethane is a more rigid material but makes up for the disadvantages of rubber bushing. Polyurethane bushings are also typically considered an upgrade from rubber.
Pipe Bushing. A cylinder-shaped lining designed to lessen friction and wearing, it also constricts and restricts motion of mechanical parts between larger diameter pipes and smaller diameter pipes.
Plastic Bushing. One of the chief materials in bushing is plastic due to the fact that it’s relatively easy to manufacture, it’s durable, malleable, and most importantly, it’s cheap. It can also be found in customized shapes and can withstand extreme temperatures and hazardous environments with high levels of shock and vibration.
Threaded Bushing. A helical or tapered bushing that is used to convert between rotating and linear movement. It also connects threaded pipes and hoses and caps and fixtures, to each other. It is usually used for adjustment mechanisms.
There are still plenty of types of bushings out in the market today and because it has a very specific and important function, you have to make sure that you are choosing the right one for your machine, whether it’s for a bike or for a car. If you’re interested in reading this article, you’ll surely be interested in learning how to replace a car’s clutch and as a bonus, read how to install training wheels.