News Column

Patent Issued for Fluid Dynamic Bearing Motor Including Plastic Component

July 22, 2014

By a News Reporter-Staff News Editor at Journal of Technology -- Seagate Technology LLC (Cupertino, CA) has been issued patent number 8770843, according to news reporting originating out of Alexandria, Virginia, by VerticalNews editors.

The patent's inventors are Grantz, Alan L. (Aptos, CA); Kloeppel, Klaus D. (Watsonville, CA).

This patent was filed on March 18, 2013 and was published online on July 8, 2014.

From the background information supplied by the inventors, news correspondents obtained the following quote: "Disc drive memory systems store digital information that is recorded on concentric tracks of a magnetic disc medium. At least one disc is rotatably mounted on a spindle, and the information, which can be stored in the form of magnetic transitions within the discs, is accessed using read/write heads or transducers. A drive controller is conventionally used for controlling the disc drive system based on commands received from a host system. The drive controller controls the disc drive to store and retrieve information from the magnetic discs. The read/write heads are located on a pivoting arm that moves radially over the surface of the disc. The discs are rotated at high speeds during operation using an electric motor located inside a hub or below the discs. Magnets on the hub interact with a stator to cause rotation of the hub relative to the stator. One type of motor has a spindle mounted by means of a bearing system to a motor shaft disposed in the center of the hub. The bearings permit rotational movement between the shaft and the sleeve, while maintaining alignment of the spindle to the shaft. The read/write heads must be accurately aligned with the storage tracks on the disc to ensure the proper reading and writing of information.

"These disc drive memory systems are being utilized in progressively more environments besides traditional stationary computing environments. Recently, disc drive memory systems are incorporated into devices that are operated in mobile environments including digital cameras, digital video cameras, GPS devices, video game consoles and personal music players, in addition to portable computers. As such, performance and design needs have intensified including improved resistance to shock, improved robustness and reduced power consumption. Further, a demand exists for increased storage capacity and smaller disc drives, which has led to the design of higher recording areal density such that the read/write heads are placed increasingly closer to the disc surface. Because rotational accuracy is critical, disc drives currently utilize a spindle motor having fluid dynamic bearings (FDB) between a shaft and sleeve to support a hub and the disc for rotation. In a hydrodynamic bearing, a lubricating fluid provides a bearing surface between a fixed member and a rotating member of the disc drive. Hydrodynamic bearings, however, suffer from sensitivity to external loads or mechanical shock, which can jar fluid from the bearing. Fluid containment is critical to the life of a motor, and designs have tended to increase component complexity.

"Presently, motor component design complexity requires many machining operations, which increases the costs of components. The basic component geometry of a motor component may require removal of a substantial amount of metal, depending on the form factor, and therefore the machining costs are significant in relation to the overall finished motor cost. Multiple components must be precisely assembled in order to achieve a motor construction that is able to perform with or as a fluid bearing, and that allows appropriate fluid containment. Electrochemical machining (ECM) processes typically incorporate bearing structures (i.e., grooves and lands) into metal parts. However, to utilize ECM, metal parts and accurate process interface surfaces are required. Metal parts may also require additional coating (i.e., DLC) to ensure appropriate wear performance."

Supplementing the background information on this patent, VerticalNews reporters also obtained the inventors' summary information for this patent: "The present invention provides a molded plastic component for fluid dynamic bearing (FDB) motors. The FDB motor includes a fluid dynamic bearing containing fluid defined between an inner component and an outer component, wherein the inner component and the outer component are positioned for relative rotation. At least a portion of the outer component is plastic formed by a molding process. The outer component has a plastic surface that faces and defines a fluid bearing with the inner component. Alternatively, the outer component is affixed to a metal component, wherein the metal component has a metal surface that faces and defines a fluid bearing with the inner component. These and various other features and advantages will be apparent from a reading of the following detailed description."

For the URL and additional information on this patent, see: Grantz, Alan L.; Kloeppel, Klaus D.. Fluid Dynamic Bearing Motor Including Plastic Component. U.S. Patent Number 8770843, filed March 18, 2013, and published online on July 8, 2014. Patent URL:

Keywords for this news article include: Seagate Technology LLC.

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Source: Journal of Technology

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