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US 6,149,161 AGranted
Grooved pumping seal
AssigneeSeagate Technology LLC
InventorsAlan L. Grantz, Roger A. Addy, Robert A. Nottingham
Life of this patent
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AssigneeSeagate Technology LLC
InventorsAlan L. Grantz, Roger A. Addy, Robert A. Nottingham
Estimating the term…
An improved seal for a hydrodynamic bearing which aids in making the bearing less sensitive to changes in load and rotational speed, which is especially useful in hydrodynamic bearing motor in which the bearing is open at both the upper and lower ends. Additionally, a hydrodynamic bearing open at both ends in which the balance of fluid flow or pressure within the total system is maintained, and a seal usable to make a hydrodynamic bearing which is as stiff or stiffer than known standard spindle motors with hydrodynamic bearings which are supported only at one end. Also, 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 is disclosed.
A grooved pumping seal especially designed to provide substantial sealing stiffness utilizing active pumping adjacent to a hydrodynamic bearing said seal comprising a shaft and a sleeve mounted for relative rotation, one of said shaft and said sleeve comprising means for storing bearing fluid when said shaft and said sleeve are at rest, adjacent to means for establishing sealing pressure adjacent said bearing when said shaft and said sleeve are relatively rotating to prevent loss of fluid from said bearing.
In a motor for use in a disc drive comprising a shaft and a sleeve around a portion of said shaft, a substantially conical hydrodynamic bearing at each end of said shaft comprising a cone supported from said shaft and a sleeve having a surface facing a surface of said cone, said sleeve further defining a grooved pumping seal comprising first and second adjacent regions on said shaft, said first region comprising a reservoir for storing fluid, said second region comprising means for establishing sealing stiffness adjacent said hydrodynamic bearing and axially adjacent said bearing cone, said grooved pumping seal second region comprising a section of said shaft surrounded by said sleeve having fine pitch pumping grooves circumferentially spaced along at least a section thereof, said grooves having a spacing and pitch to create a pressure gradient toward said bearing cone so that fluid in a bearing gap between said bearing cone and said bearing seat is maintained in said gap.
Dependencies are inferred from the claim text.