Overview of plain bearings

According to the different friction properties in bearings, bearings can be divided into two categories: sliding bearings (referred to as sliding bearings) and rolling bearings (referred to as rolling bearings).

Because of the low friction coefficient and low starting resistance of rolling bearings, and it has been standardized, it is very convenient for design, use, lubrication and maintenance, so it is widely used in general machines. However, because the sliding bearing itself has a lot of resistance, it still occupies an important position in some occasions. At present, sliding bearings are mainly used in the following situations:

Bearings with extremely high working speed.

Bearings that require a particularly precise bearing position for the shaft.

Extra heavy duty bearings.

Bearings subject to enormous shock and vibration loads.

According to assembly requirements, split bearings (such as crankshaft bearings) must be made.

Bearings that work under special working conditions (such as in water or corrosive media).

Sliding bearings are also often used when the radial space size of the bearing is limited.

Therefore, sliding bearings are still widely used in aero-engine accessories, instruments, metal cutting machine tools, internal combustion engines, railway locomotives and vehicles, rolling mills, radar, satellite communication ground stations and astronomical telescopes.

There are many types of sliding bearings, which can be divided into radial bearings (supporting radial loads) and thrust bearings (supporting axial loads) according to the direction of the load. According to the different lubrication states between the sliding surfaces (only liquid lubrication is discussed in this book), i is divided into liquid lubricated bearings, incomplete liquid lubricated bearings (referring to the boundary lubrication or mixed lubrication between the sliding surfaces) and non-lubricated bearings (referring to working before and during operation without lubricant). According to the different bearing mechanisms of liquid lubrication, it can be divided into hydrodynamic lubrication bearings (referred to as hydrodynamic bearings) and hydrostatic lubrication bearings (referred to as hydrostatic bearings). This chapter mainly discusses hydrodynamic bearing.

To design a sliding bearing correctly, the following problems must be reasonably solved:

The form and structure of the bearing;

The structure and material selection of the bearing shell;< /p>

Bearing structural parameters;

Lubricant selection and application;

Bearing capacity and heat balance calculation.