Grooved pumping seal

DETAILED DESCRIPTION Thus, it is an object of the present invention to create an improved seal for a hydrodynamic bearing; more particularly, the objective is to provide a seal which aids in making the bearing less sensitive to changes in load and rotational speed.
Another objective is to maintain the fluid in the hydrodynamic bearing gap by providing an adjacent seal with substantial sealing stiffness, wherein the term sealing stiffness represents the ability of the seal to retain the fluid within the gap of the adjacent hydrodynamic bearing.
Yet another objective of the present invention is to provide a seal which is especially useful in hydrodynamic bearing motor in which the bearing is open at both the upper and lower ends.
A related objective of the invention is to provide a hydrodynamic bearing open at both ends in which the balance of fluid flow or pressure within the hydrodynamic bearing system is maintained.
Another objective of the invention is to provide a seal usable to establish substantial sealing pressure adjacent a hydrodynamic bearing to maintain bearing fluid therein.
Another objective is to provide a pumping seal useful in a hydrodynamic bearing design to maintain balanced internal fluid pressures during operation to minimize the likelihood of any lubricating fluid being lost during operation.
These and other objectives of the present invention are achieved by providing a grooved pumping seal which is a capillary seal which employs active pumping to enhance its stiffness.
The seal, which is typically incorporated in a hydrodynamic bearing to enhance the stiffness of a fluid dynamic bearing motor, especially of the type which is open at both ends as with top cover attached type motors, comprises a sleeve which surrounds a shaft, typically adjacent to a conical or spherical bearing.
Preferably, the sleeve portion of the grooved pumping seal lies between the cone or sphere of the bearing and the central shaft portion of the motor, and surrounds the shaft to be separated from the shaft by a very narrow gap