What are the Types of Aircraft Plain Bearings?

A plain bearing, sometimes referred to as a bushing, is a mechanical component implemented to minimize friction between a rotating shaft and its stationary support pieces. They are usually made from soft metal or plastic and feature an oil film in order to support the rotating shaft on the much harder shaft journal. Plain bearings are manufactured in many types and have a variety of functions. This blog will serve to explain a bit about each type of plain bearing and their uses.

Hydrodynamic and Babbitted Journal Bearings

This type of bearing is often used to support an engine crankshaft, with the bearings themselves seated in the crankcase. Main engine bearings operate in the ‘hydrodynamic regime’ meaning that the bearings are under normal conditions and the journals and bearings are kept separate by an oil wedge that forms as the shaft rotates. The surfaces of these bearings are babbitt-lined, meaning they are encased in a soft metal that supports fluid film lubrication while providing a safe surface if it connects with the harder shaft journal.

Sleeve Bearings

Sleeve bearings are similar to hydrodynamic babbitted journal bearings, but are utilized for linear motion almost as much as they are for rotary motion. They are often made of bronze, either sintered or cast, and sometimes filled with graphite. In some cases, sleeve bearings are made of various types of plastics. These bearings come in two styles, a plain cylindrical model and a flanged style.

Spherical Bearings

Spherical bearings are specially machined bearings that allow angular rotation between linkages, control arms, and more. Spherical bearings rotate angularly while oil, PTFE, or other materials act as a lubricating layer between sliding surfaces. They are not intended to handle rotation, but often rotate as linkages move through their range.

Drill Jig Bushings

Drill jig bushings guide drills during precision metal drilling and come as press-fit single parts or two-piece renewable components that use replaceable liners. These bushings are used more often for guidance than support and are often made from harder steel than bushings intended to be used as bearings. They must be maintained very tight to avoid compromising the accuracy needed for precise machining operations.

At ASAP AM Spares, owned and operated by ASAP Semiconductor, we can help you find all types of plain bearings for the aerospace, civil aviation, and defense industries. We’re always available and ready to help you find all the aviation parts and equipment you need, 24/7-365. For a quick and competitive quote, email us at sales@asap-amspares.com or call us at +1-714-705-4780.