To prevent thelubricating oil from leaking outside even under high pressure of the oil.
Fluid side face The front-end face of the seal is called the nose. The nose is made of rubber and forms a gasket seal when compressed on the housing shoulder.
An oil seal, also known as crankshaft retainer, is a small device, but essential to ensure the proper engine operation. It plays a key role in all moving parts of an engine, acting as a physical barrier. This mechanical seal fulfils the dual purpose of sealing a rotary shaft to maintain the necessary lubrication (avoiding leaks) and preventing other foreign matter from contaminating shafts and bearings in the rotary shaft equipment.
As type B with dust lip
• Low-friction torque design

The speed at which an oil seal can operate effectively depends on the previously outlined conditions together with the design of the seal itself. Some designs allow for a range of maximum peripheral speeds and are therefore more suitable for larger shaft diameters. Speeds below and above the recommended range can cause friction and thus impact the sealing material.