Owing to their innovative design, SKF’s HMS55 and HMSA10 metric rubber outside diameter (OD) radial shaft seals offer optimised sealing performance, extended service life and excellent oil compatibility, making these units the perfect solution for a wide range of industrial applications.  

Also referred to as SKF Edge seals, as part of the CR Seals assortment, these radial shaft seals are ideally suited for oil or grease lubricated applications with operating temperatures ranging from –40 to +100°C and up to 120 °C over short-term periods. These seals are also appropriate for sealing lubricants within a wide range of viscosities.

Andre Weyers, SKF Product Manager: Seals, unpacks several smart design features presented by the radial shaft seals: “The rubber OD provides optimised sealing ability in the housing while the beads on the OD provide improved sealing ability and retention in the bore as well as prevent spring-back during installation.”  

“The spring-loaded sealing lip contributes to a quick response in handling dynamic runout and maintaining the sealing performance, even when sealing lip wear is excessive,” continues Weyers. The sealing lip and flex section are optimally balanced to withstand both high dynamic runout and shaft-to-bore misalignment. The auxiliary lip on the HMSA10 seals is non-contacting, enabling these units to operate at the same speeds as the single-lip HMS5 seals.

The HMS5 and HSMA10 seals are manufactured from optimised RG nitrile rubber compound which is the result of SKF’s extensive experience as well as the latest findings from the development of SKF seal material. Endurance test results show that the service life of seals manufactured from this advanced compound is significantly extended.

In addition to providing good resistance to ageing and wear, excellent pumping ability is another advantage presented by the material. Weyers explains that pumping ability is defined as ‘the time it takes for the seal to return a certain amount of oil from the air side to the oil side’. The microstructure of SKF’s RG nitrile rubber compound promotes the rapid pumping of the oil. 

Weyers notes that the complete range of HMS5 and HMSA10 seals is also available in a fluoro rubber compound with a stainless steel garter spring. “This Viton rubber compound is used in applications where temperatures exceed the limits of nitrile rubber.” The temperature range for the SKF developed Viton material is -40 to 200°C and will withstand temperatures off 220°C for short peak periods.

Designed in accordance with ISO 6194-1 and DIN 3760, the available size range of HMS5 and HMSA10 seals includes a full coverage of the ISO 6194-1 and DIN 3760 dimensions for shaft diameters up to 500 mm. “An extensive range of dimensions commonly used in the market is also available and new dimensions are continually added,” concludes Weyers.