Outside diameter design
The standard assortment of radial shaft seals manufactured by SKF for general industrial applications covers three different outside diameter executions.
Seals with a rubber outside diameter (fig 1) are used in a wide range of applications. They maintain a tight fit in the housing bore when the housing material has a higher coefficient of thermal expansion than steel and/or when the housing is split. They are also recommended in all applications where the housing bore surface finish requirements cannot be met.
Metal-cased seals (fig 2) are multi-purpose seals that can be used for most applications. They are relatively easy to install and, provided the housing bore meets the requirements, will fit tightly and centrically in the housing bore.
Radial shaft seals designed with a metal case and a secondary reinforcement in the side face (fig 3) offer advantages where operating conditions are severe. They have a higher radial stiffness and are available for shaft diameters ≥ 50 mm (2 in.).
Besides these standard outside diameter designs, there is also a half rubber / half metal outside diameter design (fig 4) that is typically used in automotive applications.
In addition to the seal designs for general industrial applications described above, SKF also manufactures seals for heavy industrial applications with special features to meet specific requirements. For detailed information, refer to the section Seals for heavy industrial applications.