Spherical plain bearings are plain bearings, inner and outer rings of which have sphered sliding surfaces. Spherical plain bearings are designed for the transmission of radial, axial and combined loads, including shock loads in the joints of machine parts and mechanisms where it is necessary to provide with spatial complex or vibrating, rocking, rotating and simple movements at low speeds. Radial, angular contact, and thrust spherical bearings are produced depending on the nature of transmitted loads.
All spherical plain bearings can be divided into two groups according to the method of the working surface lubrication. There are bearings requiring the lubrication and self-lubricating bearings the sliding surfaces of which are made of special materials. The latter are used in the units with higher durability requirements, or when there are difficulties in supports maintenance when it is unreasonable to use lubrication requiring bearings.
The bearings with protective contact seals are manufactured to protect sliding surfaces from the environmental effects and to keep the lubricant in.
When choosing a type of spherical plain bearing, it is necessary to take into account many factors comprising a number of contradictions to be resolved or optimally balanced.