oil seal

oil seal

 or shaft seal

In machines, a device that prevents the passage of fluids along a rotating shaft. Seals are necessary when a shaft extends from a housing (enclosure) containing oil, such as a pump or a gearbox. Leather, synthetic rubber, and silicones are among the materials used for the sealing ring. See also bearing.

---

oil seal [′ȯil ‚sēl]

(engineering)

A device for preventing the entry or return of oil from a chamber.

A device using oil as the sealing medium to prevent the passage of fluid from one chamber to another.