Seagate Technology Incorporated

Seagate Technologies, Inc.

Jeffry A LeBlanc

Troy Michael Herndon

Robert Alan Nottingham

Norbert Steven Parsoneault

Lynn B Le

Mohammad Mahbubul Ameen

Raquib U Kahn

A component for restricting relative movement of a rotor and a shaft is disclosed. A motor may include a shaft and a rotor, where the rotor is disposed for relative rotation with respect to said shaft. A component is operable to restrict relative movement of the rotor and the shaft, where the component includes a first surface operable to receive a fluid.

Lubricated limiter for fluid dynamic bearing motor

For motors having a journal with one or more groove regions and a shaft for relative rotation in the journal, aspects include providing a dual tapered shaft. The shaft may be tapered by the application of a wear resistant coating at least opposite the groove regions. The coating introduces a shaft taper from near a top end and from near a bottom end towards the shaft middle. The shaft taper may provide for improved pumping efficiency. The coating may be applied in various processes such as chemical vapor deposition or physical vapor deposition to establish a thickness gradient of coating material from near the top end and near the bottom end towards the shaft middle. In one example, the coating includes a DLC coating. Additionally, shaft portions may be shielded to prevent coatings thereon.

Dual tapered shaft for FDB motor

In one example, a FDB motor having a top-cover attached, EM biased bearing system is provided. The motor includes a shaft and rotor disposed for relative rotation, and an axial limiter for restricting axial movement of the rotor with respect to the shaft, wherein the axial limiter is wet or lubricated during contact. The limiter is spatially fixed with respect to one of the shaft or the rotor and disposed with an axial end surface opposing a surface portion spatially fixed with respect to the other of the shaft or the rotor to form a gap therebetween. The gap may be filled with a fluid such as bearing lubricant, thereby providing a lubricated or wet contact surface to restrict axial movement of the shaft and rotor. Additionally, one or both surfaces may include a groove or slot to provide circulation of fluid through the gap.

In one aspect of the invention, a motor having improved stiffness is provided. In one embodiment, the motor includes a stationary shaft, a hub, a thrust plate and a counter plate. The thrust plate is coupled to the shaft. The hub is rotatable about a central axis of the shaft. The counter plate is coupled to the hub and has the shaft extending therethrough. The counter plate and the thrust plate define at least a portion of a fluid dynamic bearing, wherein at least a portion of counter plate and the thrust plate form a capillary seal therebetween. The capillary seal enhances motor performance by providing a fluid reservoir for the fluid dynamic bearing, allowing fluid to be added to the hydrodynamic bearing without motor disassembly and providing a passage for air to escape from between the bearing surfaces. In one embodiment, the motor is particularly suitable for disc drive applications.

Top cover attached single plate fluid dynamic bearing motor

A robust spindle motor is provided having added shock resistance for fluid containment. In an aspect, a high-speed centrifugal capillary seal contains a fluid reservoir extending between similarly rotatable components. Fluid is recirculated through the motor and substantially around a counterplate. Proper axial positioning of motor components and stiffness is maintained in motors supporting heavy loads such as a disk drive memory system having a weighty disc pack. In an aspect, two separate thrust surfaces provide oppositely directed axial forces acting on motor components. In an aspect, a single thrust plate that is comparatively small is utilized, reducing power consumption. Also, a thrust bearing situated inboard of a capillary seal forms a comparatively small diameter thrust plate gap. The comparatively small diameter thrust plate gap increases efficiency and characteristics including surface flatness, run out and perpendicularity are improved.

High-speed centrifugal seal for a spindle motor

The present invention provides a hydrodynamic bearing design which is simple and reliable in design, while incorporating a shaft with a plug of high elastic modulus material fitted within a cylinder of a lower elastic modulus material than that of the plug, thereby compensating for temperature variations while maintaining radial stiffness of the system over a wide range of temperatures. The design is relatively inexpensive and easy to replicate in a high volume manufacturing process.

Stiffness compensation for a thermally compensated fluid dynamic bearing

A spindle motor incorporates a shaft having a known outer diameter and a stator having a known inner diameter which is slightly larger than the outer diameter of the shaft so that it may slip over the shaft. Die cut sharp features are defined in the inner diameter of the stator laminations. These features extending radially inward from the generally circular inner diameter of the stator laminations so that these features establish an interference fit with the outer surface of the shaft which the structure is mounted. When the stack is pressed onto the outer surface of the shaft to which it is mounted and supported, the coating on the stack will scrape off, thus establishing a metal-to-metal contact between the stack and the adjoining outer surface of the shaft. As a result of this, a tight interference fit will be established between the inner surface of the stack and the outer surface of the shaft, thus both radially fixing the stack on the shaft, and grounding the stack to the shaft.

Lamination features for stator grounding

The cone which is pressed onto or otherwise affixed to the shaft to cooperate with the sleeve to form a conical hydrodynamic bearing is modified to provide a flat surface at the axially outer end of the cone most distant from the conical surface which is used to form the conical bearing in cooperation with the bearing seat of the sleeve and the intervening fluid. The sleeve surface facing the second angled surface of the bearing cone is modified to diverge more sharply away from the second surface of the cone, or to simply be spaced further away. In this way, a larger reservoir is formed, diminishing the possibility of oil evaporation and oil loss. Finally, a relatively flat shield is supported from the sleeve overlying the flat upper surface of the cone. The divergence of the upper bearing cone surface from the surrounding sleeve also allows for filling the bearing before the shield is installed. This solves the problem of trying to fill the bearing through a small hole either directly in the protective shield or between the protective shield and the outer diameter of the shaft. Not having the hole in the shield also lowers the likelihood of evaporation or splash loss of oil from the conical bearing.

Easy-fill, easy-press conical bearing

A disc drive spindle motor having improved acoustic properties for use in a disc drive data storage system is provided. In one embodiment, the disc drive spindle motor a base, a stationary member, a rotor and a stator. A bearing interconnects the rotor with the stationary member and allows the rotor to rotate about the stationary member. The stator includes a plurality of teeth extending from a back iron. At least one stiffening member is coupled to the stator, joining the teeth at an end opposite the back iron. The stiffening member substantially reduces vibrations in the stator thereby reducing acoustic noise generated by the motor.

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Aptos, CA, United States of America

Jeffry A LeBlanc