National/ Timken Seals Catalog - Norfolkbearings.com

SECTION 1-A TECHNICALOIL SEAL DESIGN AND SELECTIONTHE SEAL AND ITS FUNCTIONOil Seal DefinitionAs products, oil seals may be simply described as devices that close or seal the spaces between stationary and movingcomponents in mechanical equipment . . .they prevent lubricant from escaping.Oil seals often called grease, fluid or dirt seals are the vital components of practically every type of machine and vehiclein operation. These seals fulfill an exacting function . . . they protect all types of precision constructed, close fitting ball,sleeve and roller bearings.Oil Seal FunctionOil seals are used wherever shafts rotate and bearings require lubrication. In short, a seal is a barrier with three basicfunctions: 1) Retaining lubricants and liquids 2) Excluding contaminants 3) Seal or separate dissimilar fluids or gases.• Precision bearings rely on the oil seal to prevent lubricants from escaping the bearings or a specific area.• Components of machines rely on the oil seal to prevent abrasives, corrosive moisture and other harmful contaminantsfrom entering the mechanics of the machine.• Separation of fluids and gases may completely rely on the seal to prevent intermixture of two different mediumssuch as lubricating oil and water.Oil Seal In UseIn a typical application, the oil seal is installed adjacent to a bearing, sealing in or sealing out, as necessary, the variousliquids, gases or solids encountered by the particular mechanism.HOUSINGHOUSINGSHAFTSHAFTWithout an oil seal . . . essential lubricant can escapethrough the bearing and . . . harmful dirt and foreignmatter can enter.With a properly designed and fitted oil seal . . . the spacebetween the housing and shaft is securely closed orsealed. Lubricant cannot escape . . . harmful dirt andforeign matter cannot enter.TECHNICAL SECTIONIII