A radial shaft seal seals a rotating shaft against a housing. VR radial shaft seals have especially been developed to withstand high peripheral velocities and high pressure loads.

Sealing mechanism of VR seals

The operating principle of this springless VR radial shaft seal is due to the fact that rubber-elastic diaphragm bodies with a precisely tuned pretension are applied by means of supporting elements made of steel or other metals. The oblique sealing lip, which adjoins the diaphragm body, is set outwards or inwards depending on the assembly situation and pressure direction of the medium to be sealed.

The sealing mechanism results from the radially and tangentially pretensioned diaphragm body. A spring effect of the diaphragm body to the sealing lip is produced. A radial and a tangential force of the sealing lip act against the resulting shear stresses in case of rotating axes. Vibrations and possible static and dynamic concentricity deviations are absorbed directly in the sealing lip area. A partial lifting of the sealing lip with a rotating shaft and the associated pump effect is low in this seal ring construction.

Extensive comparative measurements have shown that the VR Lip Seal requires only 1/3 to 1/4 of the radial force with the same sealing performance compared to the normal spring-supported sealing element, thus positively influencing the energy efficient requirements for modern products.

Thus, it becomes possible to allow this type of seal to run on unhardened and stainless steel shafts without destroying scoring or grooves. Even after more than a thousand running hours, only a polishing track produced by the sealing lip is visible on the shaft.