HYDRODYNAMIC SEAL AND METHOD OF MAKING THE SAME

摘要

A hydrodynamic shaft seal (12) formed with a spiral hydrodynamic channel (54) in which successive turns of the channel (54) are of progressively diminishing volume toward an air side (24) of the seal. The channel (54) is made by forming a spirally extending first cut (63) in a surface of the seal, and forming a spirally extending second cut (65) in the surface of the seal adjacent to the first cut such that the first and second cuts intersect below the surface of the seal to produce a spiral channel (54). The spiral of the first cut (63) has a lead different from the lead of the second cut (65) such that the channel (54) is of progressively diminishing volume along its length. Alternatively, the second cut (165) may have the same lead as the first cut (163) for the first few turns, after which the lead of the second cut (165) may be reduced, to provide a channel of constant volume (154) for the first few turns, followed by a channel portion of reduced volume.