auto oil seals Shaft Requirements
Proper engineering of the components of the assembly is necessary for seal reliability. Shaft requirements have been determined by the Rubber Manufacturer’s Association, which includes Federal-Mogul Corporation, through thousands of hours of testing. The following items should be considered at the original equipment design stage or whenever an existing application is to be upgraded.
Shaft Finish — Shaft finish, a prime factor in proper functioning of a lip seal, should be specified as 10-25 micro inches Ra (0.20-0.60 micrometers Ra) with no machine lead.
Shaft Lead — Maximum permissible lead angle is 0 ± 0.05°. The most acceptable method for obtaining this surface characteristic is plunge grinding.
Shaft Diameter — Shaft diameter tolerances are shown below. silicon seal.Tolerances that are greater than those shown should be used only if agreed upon between user and supplier.
Shaft Hardness — Radial lip type seals will function satisfactorily on mild steel, cast iron or malleable iron shafts. Under normal conditions, however, the section of the shaft contacted by the sealing lip should be hardened to Rockwell C30 minimum.rubber sealing. If, however, the shaft may be nicked or damaged during handling or assembly, a Rockwell C45 minimum is recommended.auto oil seals Shaft Requirements.
Shaft Chamfer — To aid installation and help prevent damage to the seal lip, viton seal,the leading edge of the shaft should have a chamfer or radius which must be smooth and free of nicks or rough spots.valve seal.
Shaft-to-Bore Misalignment (STBM) — The distance the center of rotation is displaced from the center of the bore. It usually exists to some degree due to normal machining and assembly tolerances. Misalignment results in uneven wear and, if excessive, will shorten seal life. To measure, attach a dial indicator to the shaft and indicate off the seal bore while rotating the shaft.auto oil seals Shaft Requirements.
Dynamic Runout— Twice the distance the center of the shaft is displaced from the center of rotation. It can result from a bent shaft, lack of shaft balance or other manufacturing variables. To measure, find the total movement of an indicator held against the seal area of the slowly rotating shaft.cap seal.
Shaft Material — Steel, stainless steel and certain cast irons all provide good sealing surfaces if finished properly. Brass or bronze shafts are not recommended nor are alloys of aluminum, zinc, magnesium and other similar elements. If plating is considered, it should be hard nonporous chrome plate. Flaking or plating exposes razor edges which may cut the seal lip.auto oil seals Shaft Requirements.auto oil seals
Proper engineering of the components of the assembly is necessary for seal reliability. Shaft requirements have been determined by the Rubber Manufacturer’s Association, which includes Federal-Mogul Corporation, through thousands of hours of testing. The following items should be considered at the original equipment design stage or whenever an existing application is to be upgraded.
Shaft Finish — Shaft finish, a prime factor in proper functioning of a lip seal, should be specified as 10-25 micro inches Ra (0.20-0.60 micrometers Ra) with no machine lead.
Shaft Lead — Maximum permissible lead angle is 0 ± 0.05°. The most acceptable method for obtaining this surface characteristic is plunge grinding.
Shaft Diameter — Shaft diameter tolerances are shown below. silicon seal.Tolerances that are greater than those shown should be used only if agreed upon between user and supplier.
Shaft Hardness — Radial lip type seals will function satisfactorily on mild steel, cast iron or malleable iron shafts. Under normal conditions, however, the section of the shaft contacted by the sealing lip should be hardened to Rockwell C30 minimum.rubber sealing. If, however, the shaft may be nicked or damaged during handling or assembly, a Rockwell C45 minimum is recommended.auto oil seals Shaft Requirements.
Shaft Chamfer — To aid installation and help prevent damage to the seal lip, viton seal,the leading edge of the shaft should have a chamfer or radius which must be smooth and free of nicks or rough spots.valve seal.
Shaft-to-Bore Misalignment (STBM) — The distance the center of rotation is displaced from the center of the bore. It usually exists to some degree due to normal machining and assembly tolerances. Misalignment results in uneven wear and, if excessive, will shorten seal life. To measure, attach a dial indicator to the shaft and indicate off the seal bore while rotating the shaft.auto oil seals Shaft Requirements.
Dynamic Runout— Twice the distance the center of the shaft is displaced from the center of rotation. It can result from a bent shaft, lack of shaft balance or other manufacturing variables. To measure, find the total movement of an indicator held against the seal area of the slowly rotating shaft.cap seal.
Shaft Material — Steel, stainless steel and certain cast irons all provide good sealing surfaces if finished properly. Brass or bronze shafts are not recommended nor are alloys of aluminum, zinc, magnesium and other similar elements. If plating is considered, it should be hard nonporous chrome plate. Flaking or plating exposes razor edges which may cut the seal lip.auto oil seals Shaft Requirements.auto oil seals
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