Radial Shaft Seals
Radial shaft seals are used between rotating and stationary machine components or between two components in relative motion and consist of two main parts:
A cylindrical outer covering of sheet steel (case) or elastomer that has the requisite interference fit to seal statically against the housing bore.
A sealing lip made of an elastomeric or thermoplastic material that seals dynamically and statically against the shaft. The lip has a sealing edge that is formed by molding, cutting or grinding. It is normally pressed against the counter face surface of the shaft, with a defined radial load, by a garter spring. The edge of the sealing lip and the shaft counter face surface form the most important functional area of a radial shaft seal. The sealing effect of the lip can be enhanced by designing the contact area of the lip with hydrodynamic features.