A typical bushing/plain bearing is a cylindrical lining designed to reduce friction and wear, or constrict and restrain motion of mechanical parts. One type of bushing is a hardened threaded fixing hole that allows one assembly to be fixed to another by means of a screw or threaded bolt.
The unique thing about aircraft bushings (those used for complicated airplanes parts and the life) is that it has many variations for all airplane needs, from engine to throttle. There are about three main types of aircraft bushings, with a myriad of examples for each:
Rolling Element
Deep groove ball: These are by far the world’s most prolific bearing type. Capable of numerous applications and coming in many formats, the deep groove ball bearing is every design engineers first thought for low friction requirements.
Angular contact: These have one ring shoulder partially or totally removed. This allows a larger ball complement than found in comparable deep groove bearings, hence a greater load capacity.
The Taper roller: This design has been with us for many years. Its construction allows radial and axial loads to be applied and absorbs impact and shock loads with ease if properly fitted.
Needle roller: Typical products for this type include cam followers, yoke rollers, cage assemblies, drawn cup, inner-less, aligning types, combined ball and roller units, inner rings and axial or thrust needle roller assemblies.
Slewing rings: Often found in lifting, mining and military applications, the slewing ring provides a large scale solution for high loads and controlled turning.
Housed bearing units: Housed (or plumber block bearings as they are also known) come in a variety of formats. Both inserts and housings can take various forms both in terms of material and design.
Self-lube units: Normally consisting of either a cast iron or pressed steel housing with a bearing insert, the Self-lube unit® offers an easy to fit, maintain and replace bearing system.
Spherical rollers: Spherical roller bearings are designed to take misalignment, reasonable speeds (dependent on application details) and high loads.
Cylindrical rollers: Cylindrical roller bearings are typically used in combination with double direction angular contact thrust bearings where radial stiffness, high radial capacity and high precision support are required.
The Split rollers: The Split Roller Bearing (SRB) range offers an alternative to the well known Cooper Bearing range of split roller bearings.
Plain Type
The Oilite: Simply comprising of a sintered bronze material impregnated with oil, this self-lubricating bearing is most commonly found in tough applications where re-lubrication of a rolling element bearing is simply not possible.
Rod end: You can be supplied with many types of rod end, from standard and non-standard applications. Apart from normal features, it also has defined break out torques, specialist housing and ball materials, specialist thread requirements and solutions for high wear/fatigue environments.
Spherical plain: There are many types of plain spherical bearings with metal on bronze, metal to metal or metal available in the market.
Tilt pad: Tilt pad bearings can be found in many medium to large scale applications. For example, medium and heavy duty motors, turbines, gearboxes, compressors are all highly likely to have such devices.
Thrust pad: Thrust pad bearing sets are often found in milling and heavy machine applications. Like their tilt pad cousin, thrust pads rely on a hydro-dynamic oil film to transfer load to the pads.
Linear types
Linear bushing: This is a high precision linear motion bearing that achieves endless linear motion by traveling along a shaft. This product covers a massive range of applications. Stroke Rotary Bushing, for example, has the ability to combine linear and rotation movement along a shaft with limited stroke depending on the size. Applications such as low friction and high speed are ideal for this bearing.
Ball screw bearings: These are used when linear motion is required to carry medium/high loads with relatively high accuracy. Reliability, accuracy and smooth operation are paramount in most ball screw applications.