Oil seal SKF 2084051 Oil Seals is a general seal of the customary name, as the name suggests: 
oil seal is used to seal the oil (oil is the most common liquid transmission system,  also refers to the general liquid material) mechanical components. From the seal of the seal, the characteristics of the type of structure, working conditions and sealing mechanism can be divided into a variety of forms and different names, but the habit of the general rotating shaft lip ring called oil seal, static seal and dynamic seal (general reciprocating motion) With seals called seals.