Oil Seals and Grease Seals Information
Oil seals and grease seals have a flexible lip that rubs against a shaft or housing to prevent the leakage or ingress of fluids anddirt. For proper installation, the seal lip should point towards the medium being contained. Some oil seals and grease seals have a spring to help keep the lip in contact with the shaft. 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. Rod seals are radial seals. The seal is press-fit into a housing bore with the sealing lip contacting the shaft. Also referred to as a shaft seal. Piston seals are radial seals. The seal is fit onto a shaft with the sealing lip contacting the housing bore. V-rings are considered external lip seals. A symmetric seal is symmetrical and works equally well as a rod or a piston seal. An axial seal seals axially against a housing or machine component.
The seal type for oil seals and grease seals can be oil seals or other types. An oil seal can also called flexible lip, radial lip, or rotary shaft seal. Oil & grease seals are used to retainor separate lubricants or fluids. These seals are primarily used for rotary applications only. Common configurations include single lip, double lip, triple lip, and four or more lips. Other seal type choices include U-ring or block vee ring, V-ring, clearance or labyrinth seals, and bearing isolators. U-ring or block vee ring seals are also called U-packings or Block Vee packings. Depending on their construction, U-rings and blockvee rings can be used as a rod seal, a piston seal or a symmetric seal. U-rings and block vee rings are single acting, or unidirectional seals, and must be mounted back-to-back in double-acting cylinder applications. ABlock Vee seal is more compact and has better performance characteristics under high pressure than a U-ring. V-ring seals are all rubber seals used primarily to exclude dirt and other contaminants. V-rings stretch over a shaft and seal against the side of a housing or other machine component. There are many different styles of clearance, or labyrinth seals. The one thing they all have in common is that they all operate on a principle of posi