HS all-rubber seals - SKF Flex seals
HS seals, available in solid and split executions, are all-rubber seals, designed without any reinforcement. They are manufactured oversized relative to the housing bore diameter and depth to enable proper compression and stability. A cover plate (fig 1 and fig 2) is required to compress the seal axially, helping to stabilize the seal in the housing bore.
A stainless steel garter spring located in the SKF Springlock groove (fig 3) provides the appropriate radial load against the shaft.
For certain applications, HS seals are also available with an auxiliary lip and/or band clamp. Contact SKF for more information.
HS seals are available in nitrile rubber, SKF Duralip, SKF Duratemp or SKF Duralife for all shaft diameters within the ranges listed in the table. A selection of available sizes is listed in the product table. Contact your SKF sales representative for additional information regarding availability.
HS solid seals
Standard solid HS seals can accommodate shaft diameters starting at 165 mm (6.5 in.) but basically do not have an upper size limit.
Both designs have a threaded spring connection (fig 10).
HS split seals
In applications where shaft removal is impractical, HS all-rubber split seals are an excellent choice. They are simply placed around the shaft and pushed into the housing bore with the split at the 12 o’clock position. A cover plate must be used to compress the seal axially to stabilize it in the housing bore.
HS split seals perform best with grease or high-viscosity lubricants. However, low-viscosity lubricants are also suitable if the level of lubricant is kept below the shaft centre line, which is particularly important at considerable surface speeds. Split seals are preferably used on horizontal shafts, but can also be used on vertical shafts in grease lubricated applications.
HS6 seals (fig 11) are designed with a spring-loaded sealing lip and an SKF Springlock (fig 12). They feature a separate loose spring and a hook-and-eye spring connection for shaft diameters > 455 mm (18 in.) unless otherwise specified (fig 13). Smaller sizes of HS6 seals come with a threaded spring connection. For a proper fit in the housing bore, a cover plate (fig 14 and fig 15) is required.
HS7 seals (fig 16), designed for grease lubricated applications only, have a spring-loaded sealing lip and are designed with both an SKF Springlock (fig 17) and SKF Springcover (fig 18). All HS7 seals feature a control-wire spring connection (fig 19). The spring is completely enclosed and the connection is made by running the control wire into the centre of the spring coil across the split (butt joint). A built-in spring tension holds the sealing lip on the shaft. For a proper fit, a cover plate is required. Due to the unique design that enables easier installation, a gap may occur at the joint even after the cover plate is installed. It is necessary that the split be placed at the 12 o’clock position during installation. HS7 seals do not have the high-performance characteristics of other HS seals, but are the easiest to install.
HS8 seals (fig 20) are designed with a spring-loaded sealing lip, SKF Springlock (fig 21), SKF Springcover (fig 22) and a hook-and-eye spring connection (fig 23) for shaft diameters above 455 mm (18 in.). Smaller sizes of HS8 seals come with a threaded spring connection. The spring is entirely enclosed except for a small portion on either side of the split. HS8 seals provide the most effective sealing performance of all split HS seals and are the preferred design for retaining low-viscosity lubricants and for water exclusion. HS8 seals perform best on horizontal shafts, but can also be used on vertical shafts provided they are not flooded with lubricant. For a proper fit, a cover plate is required.