Abstract: 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.

Abstract: An apparatus and method are provided for sealing an outer surface 170 of a shaft 175 to an inner surface 165 of a hub 160. The seal includes a magnet 155, with top and bottom pole pieces 260, 265, and a ferrofluid 270 magnetically held in a gap 275 between the pole pieces 260, 265, and the hub 160 or the shaft 175. The top pole piece 260 has a cross-section that is L-shaped, with a horizontal portion 260a parallel to the magnet 155 and a shorter vertical portion 260b facing the shaft 175. In one version, the vertical portion 260b or the portion of the shaft 175 facing it is contoured to provide a flux gradient that axially concentrates the ferrofluid 270 in the gap 275. In another aspect, a catcher 335 is provided to reduce loss of ferrofluid 270 when the ferrofluidic seal 185 used to form an outside seal. In yet another aspect, a stationary ferrofluidic seal 345 is provided for sealing a stationary shaft 350 to a rotating hub 355.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: It is therefore an objective of the present invention to provide a hydrodynamic bearing design, which is simple and reliable in design, while incorporating means for compensating for temperature variations while maintaining the radial stiffness of the system.

Abstract: 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.

Abstract: 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.