Rotary oil seal, also known as rotary mechanical seal, is a sealing component used for shaft seals in hydraulic transmission and shaft seals or end caps in rotary shaft transmission systems. Rotating oil seals are generally composed of an elastic rubber sleeve tightly filled with gas and a metal support structure, and their working principle is based on the design of a lip seal ring. When the shaft rotates, the lip of the sealing ring forms a sealed contact area with the shaft surface, preventing liquid or lubricating oil from leaking from outside the shaft to the external environment.

Rotary oil seals are mainly divided into single type and assembly type. Assembly type is a type where the skeleton and lip materials can be freely combined, and is generally used for special oil seals. It is mainly used for sealing rotating shafts or bushings to prevent liquid or lubricating oil from leaking between the shaft and bushing, especially suitable for high-speed rotating components such as the crankshaft of an engine, the output shaft of a gearbox, etc. Rotary oil seals have a wide range of applications in industrial production and are important components to ensure the normal operation of equipment.