A plain bearing, also known as a plane bearing[1] or a friction bearing is the simplest type of bearing, comprising just a bearing surface and no rolling elements. Therefore the journal (i.e., the part of the shaft in contact with the bearing) slides over the bearing surface. The simplest example of a plain bearing is a shaft rotating in a hole. A simple linear bearing can be a pair of flat surfaces designed to allow motion; e.g., a drawer and the slides it rests on or the ways on the bed of a lathe.

 

Plain bearings, in general, are the least expensive type of bearing. They are also compact and lightweight, and they have a high load-carrying capacity.

 

The design of a plain bearings depends on the type of motion the bearing must provide. The three types of motions possible are:

Journal (friction, radial or rotary) bearing: This is the most common type of plain bearing; it is simply a shaft rotating in a bearing.

In locomotive applications a journal bearing specifically referred to the plain bearing once used at the ends of the axles of railroad wheel sets, enclosed by journal boxesLinear bearing: This bearing provides linear motion; it may take the form of a circular bearing and shaft or any other two matching surfaces (e.g., a slide plate).

Thrust bearing: A thrust bearing provides a bearing surface for forces acting axial to the shaft.

Integral plain bearings are built into the object of use. It is a hole that has been prepared into a bearing surface. Industrial integral bearings are usually made from cast iron or babbitt and a hardened steel shaft is used in the bearing.

 

Integral bearings are not as common because bushings are easy to accommodate and if they wear out then they are just replaced.[3] Depending on the material an integral bearing may be less expensive but it cannot be replaced. If an integral bearing wears out then the item may be replaced or reworked to accept a bushing. Integral bearings were very common in 19th-century machinery but became progressively less common as interchangeable manufacture permeated the industry.

 

An example of a common integral plain bearing is the hinge, which is both a thrust bearing and a journal bearing.Thanks to our global production and supply network, we are able to offer customers throughout the world the industry's most extensive range of self-lubricating and prelubricated plain bearings for literally thousands of applications in scores of industries. Our high performance bearing specialists have the experience and expertise to provide innovative solutions to even the most challenging applications. As a nimble supplier with flexible manufacturing, we can respond quickly to customer needs with either standard or customized products. And our advanced R&D and testing facilities help us deliver comprehensive solutions and assure their performance, reliability and cost-effectiveness.