Oil Seals
Oil seals or grease seals are used to separate or retain fluids and lubricants. Oil seals are also referred to as rotary shaft seals, flexible lip or radial lip. Oil seals are designed in a variety of shapes and sizes and they are typically made out of flexible materials and/or metallic materials. Oil seals have a flexible lip that rubs against the housing or shaft to prevent the entry of dirt or other fluids. The flexible lip also prevents leakage. Many oil seals are designed with a spring which helps keep the seal lip in close contact with the housing or shaft. Oil seals and grease seals are used for rotary applications and configurations range from single and double lip up to four lips of more.There are a variety of different materials that are used for oil and grease seals including: rubber, nylon, nitrile, ethylene, polychloroprene and fluorosilicone, to name a few. Metallic materials range from stainless steel and bronze to cast iron. In some cases manufacturers may use their own privately owned materials.
There are many different types of oil seals including: U-ring, V-ring, bearing isolators, clearance seals and block vee ring. U-ring seals are single acting seals and they can be used as a piston or symmetrical seal or a rod seal, depending on the design. U-ring oil seals are also referred to as U-packings. V-rings can extend or stretch over the shaft and they seal against other machine components. V-rings are typically made from rubber and they prevent the entry of dirt and other contaminants. Bearing isolators are used to protect the bearings of a machine from contaminants and they consist of a stator and a rotor member.
Clearance seals are unique. Unlike other oil seals, they do not come in contact with or rub the housing or shaft of a system or machinery. Clearance seals operate well at high speeds, but they do not perform well at lower operating speeds. Block vee ring seals are also referred to as Block Vee packings and like U-rings, they can be used as a piston or symmetrical seal or a rod seal. Block vee ring seals work well under high pressure conditions and they are very compact.
Whether the oil seal is used for a car or a motorcycle or any other application, a good oil seal has the following characteristics: good design for different applications, excellent sealing performance, excellent strength under stretch, high temperatures and high pressure, good lubrication materials, good leakage protection and a long working life.