Radial shaft seals help retain lubricants and other fluids in hydraulic and pneumatic systems by sealing a rotating, oscillating, or reciprocating shaft or rod against its housing. They have a flexible lip (made of an elastomer such as nitrile or polyurethane) that comes into contact with the surface of the shaft to form a dynamic seal. Shaft seals generally have a steel outer case where the lip is bonded, and the outside diameter of the case is slightly larger than the bore of the housing to achieve a tight, press-fit seal. Double-lip seals, which have a second sealing lip, are typically used to separate two different system fluids. Radial shaft seals are used in various aircraft, automobiles, construction equipment, and foundry machines, among others.
SKF manufactures bearings, seals, and lubrication systems for automotive, energy, and other industrial applications. The company, founded in 1907 and headquartered in Gothenburg, Sweden, meets International Organization for Standardization (ISO) standards 9001 and 14001 and ISO/TS 16949.