Oil seals and grease seals have a flexible lip that rubs against a shaft or housing to prevent the leakage or ingress of fluids and dirt. Shaft speed, fluid temperature and eccentricity are but a few of the operating conditions to which the seal must adjust. The sealing orientation and direction is important to consider for oil seals and grease seals. The orientation and direction can be internal or rod seal, external or piston seal, symmetric seal, or axial seal.
The seal type for oil seals and grease seals can be oil seals or other types. An oil seal can also called flexible lip, or rotary shaft seal.