Case Selection

The most common and cost effective case materials are stamped from cold rolled carbon steel. The steel is then phosphate coated to aid in the molding process and to help eliminate corrosion during storage. Other case materials include stainless steel, brass and aluminum. These materials are considered special because of their additional cost, and are not typically used. The other option for case material is fully coated or partially coated rubber. Carbon steel cans are usually selected for rubber molded options.

The case geometry controls the positioning and rigidity of the seal lips. Often overlooked, the case type can affect the life of the sealing system. The case forms a static O.D. radial seal and is susceptible to leakage if not properly designed. The table below shows common case geometries and their advantages.

Case Selection
Application Case Type Description Example
Spring back is not acceptable Ease of installation Standard “L” Case This style of case is the most common and economical design. A chamfer or curl is used to aid in installation.  Standard L Case
Soft alloy housing Frequent removal High surface roughness Rubber Covered Case This style of case is used for soft alloy or plastic housings. Used for frequent removal and installation when damage to housing bore is a concern.  Rubber Covered Case
High surface roughness Counter bore Corrosion by sealing fluid Nose Gasket Case This style of is an economical design used when surface roughness is outside specified limits. Also for use when corrosion by sealing fluid could be a problem.  Nose Gasket Case
Ease of removal Field install Shotgun Case This style of is an economical design used when frequent removal is necessary. Also aids in installation when a field install may be needed.  Shotgun Case
Blind installation of shaft Structural rigidity Secondary or Inner Case This style is used when damage may occur to the sealing lip when shaft is installed. Also adds structural rigidity to radial shaft seal.  Secondary or Inner Case
Reduce spring back Ease of installation Heel Case This style combines the ease of installation of metal O.D. seal with O.D. sealability of rubber covered case.  Heel Case