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Oil Seal Design

As products, oil seals may be simply described as devices that close or seal the spaces between stationary and moving components 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 vehicle in operation. These seals fulfill an exacting function: they protect all types of precision constructed, close fitting ball, sleeve and roller bearings.
 
Oil seals are used wherever shafts rotate and bearings require lubrication. In short, a seal is a barrier with three basic functions: 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 contaminants from entering the mechanics of the machine.
•  Separation of fluids and gases may completely rely on the seal to prevent intermixture of two different mediums such as lubricating oil and water.
 
In a typical application, the oil seal is installed adjacent to a bearing, sealing in or sealing out, as necessary, the various liquids, gases or solids encountered by the particular mechanism.
 
        
 
The Society of Automotive Engineers (SAE) and the American Society of Testing Materials (ASTM) have developed and adapted a standard to identify component parts that make up an oil seal, as well as terminology and basic lip seal designs.
                  
       
Maximum Pressure PSI @ FPM
Shaft Finish
(Micro inch)
µ
Shaft Hardness
STBM Maximum (Shaft to Bore Misalignment @ RPM)
Maximum Shaft Dynamic Runout (DRO)
7 @ 1000
5 @ 2000
3 @ 3000
10 - 20
Above Rockwell C-45
.015” ECC @ 800 RPM
.010” ECC @ 4200 RPM
.025” TIR @ 800 RPM
.020” TIR @ 2200 RPM
.015” TIR @ 4200 RPM
7 @ 1000
5 @ 2000
3 @ 3000
10 - 20
Above Rockwell C-45
.020” ECC @ 4200 RPM
.060” TIR @ 4200 RPM
Atmospheric
10 - 25
Above Rockwell C-45
.005” ECC
.005” TIR
Atmospheric
10 – 25
Above Rockwell C-45
.010” ECC
.010” TIR
7 @ 1000
5 @ 2000
3 @ 3000
10 - 20
Above Rockwell C-45
.015” ECC @ 800 RPM
.010” ECC @ 4200 RPM
.025” TIR @ 800 RPM
.020” TIR @ 2200 RPM
.015” TIR @ 4200 RPM
2 @ 2000
100 Max.
Above Rockwell C-45
.010” ECC Max.
.015” TIR
35 @ 6500
25 Max.
Above Rockwell C-45
.025” ECC Max.
.015” TIR

   







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