Plain bearings

A plain bearing, or more commonly sliding bearing and slide bearing (in railroading sometimes called a solid bearing, journal bearing, or 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.Integral plain bearings are built into the object of use as a hole prepared in the bearing surface. Industrial integral bearings are usually made from cast iron or babbitt and a hardened steel shaft is used in the bearing.For example, a common integral plain bearing is the hinge, which is both a thrust bearing and a journal bearing.