HMS5 and HMSA10 seals

Main features

HMS5 and HMSA10
SKF metric rubber outside diameter radial shaft seals, HMS5 (fig 1) and HMSA10 (fig 2), are designed in accordance with ISO 6194-1 and DIN 3760 for use in a wide range of industrial applications. 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 250 mm (9.842 in.) as well as an extensive range of dimensions commonly used in the market. New dimensions are continually added. Main features include:
  • optimized sealing lip material
  • spring-loaded sealing lip
  • optimally balanced sealing lip and flex section
  • beaded outside diameter
  • auxiliary lip (HMSA10 seals only)


The rubber outside diameter provides optimized sealing ability in the housing, also at considerable surface roughness or in split housings. The beads on the outside diameter provide improved sealing ability and retention in the bore. They also 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.
Sealing lip and flex section are optimally balanced to withstand both high dynamic runout and shaft-to-bore misalignment.
The auxiliary lip on HMSA10 seals is non-contacting, which means that the seals normally can operate at the same speeds as the single-lip HMS5 seals.


The optimized nitrile rubber compound used for the HMS5 and HSMA10 seals has the designation suffix RG. The compound is the result of long experience and the latest findings from the SKF seal material developments. Advantages of this material include:
  • good resistance to ageing
  • very good pumping ability
  • good wear resistance
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 rapid pumping of the oil, (table). In the diagram 1, results from endurance tests show the extended service life of seals made of the optimized nitrile compound.
The complete range of HMS5 and HMSA10 seals is also available in a fluoro rubber compound with a stainless steel garter spring. This rubber compound has the designation suffix V and is used in applications where temperatures exceed the limits of nitrile rubber.

Applications and operating conditions

HMS5 and HMSA10 seals are designed for oil or grease lubricated applications with operating temperatures ranging from –40 to +100 °C (–40 to +210 °F), short-term up to 120 °C (250 °F). These seals are also appropriate for sealing lubricants within a wide range of viscosities.
Circumferential speed:up to 14 m/s (2 755 ft/min)
Operating pressure:max 0,03 MPa (5 psi)
These values are the maximum value for each service condition and should not occur together. Consideration should be given as to how the operating conditions affect each other.
SKF logo