International Business Machines Corporation

Hitachi Global Storage Technologies Netherlands B.v.

Chen-Hsiung Lee

Neal Bertram Schirle

Holavanahally Seshachar Nagaraj

David W Albrecht

Lawrence Kuhn

Ramon Lane

Larry Joe Gilliland

Francis Peter Giordano

Gene O Zierdt

James Francis Sullivan

A method and apparatus for providing magnetic wear debris collection for an air bearing of a spindle motor in a hard disk drive is disclosed. A magnetic ring is provided near one end of the journal bearing forming an air bearing. In addition, the mating surface of the air bearing is paramagnetic or ferromagnetic material. The magnetic ring, acting as a debris collector, collects debris from the air bearing to prevent deterioration of the air journal bearing. The journal bearing includes a mating surface. The mating surface may be of a paramagnetic or ferromagnetic material. A thrust bearing is provided to axially support the hub. The thrust bearing may be an oil bearing or an air bearing.

Magnetic wear debris collector for air bearing of a spindle motor in a hard disk drive

A spindle design for a hard disk drive assembly constructed in accordance with the present invention includes a significantly large gap between the rotating, ferromagnetic hub with its permanent magnet rotor and the rotating sleeve of the fluid bearing journal member. The large gap may be filled with a medium, such as air, or a non-permeable material. The large gap is preferably on the order of several hundred microns. Because of the large gap, the magnetic flux leakage from the rotating hub members and sleeve into the stationary shaft at the center of the spindle is negligible. Consequently, iron loss in the shaft caused by magnetic flux leakage into the shaft is reduced to acceptable noise levels.

Flux leakage barrier in fluid bearing for disk drive

A method and apparatus for providing magnetic wear debris collection for an air bearing of a spindle motor in a hard disk drive is disclosed. A magnetic ring is provided near one end of the journal bearing forming an air bearing. In addition, the mating surface of the air bearing is paramagnetic or ferromagnetic material. The magnetic ring, acting as a debris collector, collects debris from the air bearing to prevent wear debris form reaching the head/disk interface, which can lead to a head crash. The journal bearing includes a mating surface. The mating surface may be of a paramagnetic or ferromagnetic material. A thrust bearing is provided to axially support the hub. The thrust bearing may be an oil bearing or an air bearing.

There is provided a disk drive motor including a shaft, a thrust plate, a bearing housing positioned about the shaft, and a combination of groove sets on either the shaft or the bearing housing. The asymmetrical grooves are oriented to pump fluid in a specific direction during rotation of the housing around the shaft. Vents are also positioned to allow unwanted gases to escape.

Fluid dynamic bearing assembly

A bearing structure for a spindle motor is disclosed. The bearing structure provides a fluid bearing seal and support structure that may simultaneously addresses the problems of preventing oil leakage, of maintaining the bearing integrity under shock, of reducing oil evaporation and of minimizing distortion of the active bearing surface. The bearing structure includes a thrust plate coupled to a shaft and a bearing plate and load plate coupled to a sleeve, wherein the load plate urges the bearing plate towards the thrust plate, and wherein an adhesive is interposed between the load plate and the thrust plate. The adhesive may be an UV epoxy. The sleeve is operatively coupled to a stator, and the stator rotates the sleeve upon receiving a drive signal. The bearing further includes a diffusion barrier disposed between the sleeve and the stator. A second diffusion barrier is disposed between the load plate and the shaft. The bearing structure may also include an O-ring disposed above the bearing plate for sealing a gap between the bearing plate and the sleeve.

Fluid bearing seal and support structure

The present disclosure relates to a spindle motor having a shaft defining an axial bore that extends completely through the length of the shaft. At least a portion of the axial bore defines a fluid reservoir. A radial passageway extends radially from the fluid reservoir to an exterior surface of the shaft. The spindle motor also includes a pin that seals one end of the axial bore, and a plug that seals an opposite end of the axial bore. The motor further includes a rotor member that is rotatably mounted on the shaft. A bearing fluid forms a hydrodynamic bearing between the exterior surface of the shaft and the rotor member. The bearing fluid at least partially fills the fluid reservoir and the radial passageway.

Spindle motor with hydrodynamic bearing

A device for testing the take off speed of a thrust bearing in a disk drive spindle motor is disclosed. The device has a stationary torsion transducer that is used to support a drive shaft of the spindle motor. A load motor located adjacent to the transducer rotates the motor about the shaft while applying a radial load to the spindle motor through a belt. The load motor is attached to a linear stage which generates selected radial loads. In one version, the device also uses a ring magnet to attract the housing of spindle motor. The magnetic attraction imposes an axial force on the spindle motor and an equal reactive load on the thrust bearing. The axial load is such that the take off speed for the thrust bearing is much greater than that for the journal bearings. Under these conditions, the friction torque is dominated by the thrust bearing so that an accurate assessment of its quality may be assessed. As an alternative to the magnet, air jets may be used to apply a similar axial load to the thrust bearing.

Apparatus and method for testing thrust bearings

The method for determining the sufficiency of fluid in a hydrodynamic fluid bearing motor involves making a first determination of a range of fluid bearing fly-heights for motors having a sufficient quantity of fluid within the hydrodynamic fluid bearing, and for motors having an insufficient quantity of fluid within the hydrodynamic fluid bearing. Thereafter, the fly-height of a particular hydrodynamic fluid bearing motors can be determined and compared with the range of hydrodynamic fluid bearing fly-heights to provide a determination of the sufficiency of fluid within the particular hydrodynamic fluid bearing motor. Determining the fly-height of a particular hydrodynamic fluid bearing motor involves the utilization of non-contact displacement probes that generate a first signal indicative of the displacement of a rotating component of the bearing at a time when the component is rotating at a maximum fly-height. The probes then generate a second signal indicative of the displacement of the rotating component at a time when said component has ceased its flying within the hydrodynamic bearing. The difference between the first and second signals is an indication of the fly-height of said hydrodynamic fluid bearing of said particular motor.

Axial bearing fly-height measurement to detect oil deficiency

The present disclosure relates to a spindle motor including a shaft having an outer circumferential surface. The spindle motor also includes a thrust plate fixedly connected to the shaft. The thrust plate projects radially outward from the outer circumferential surface of the shaft and includes top and bottom surfaces. The spindle motor also includes a hub assembly mounted on the shaft. The hub assembly is adapted for mounting a storage disk. The spindle motor further includes a liquid hydrodynamic bearing and an aerodynamic bearing. The liquid hydrodynamic bearing is formed along the top and bottom surfaces of the thrust plate and is adapted for transferring loads in an axial direction relative to the shaft. The aerodynamic bearing is formed along a portion of the hub assembly and is adapted for transferring loads in a radial direction relative to the shaft.

Spindle motor with hybrid air/oil hydrodynamic bearing

A vent is disclosed for a screw mounted support shaft of a fluid dynamic bearing for a spindle of a magnetic disk file. The support shaft for mounting a spindle bushing has an axial hollow center internally threaded at one end, and has upper and lower bearing journals for rotatably mounting the spindle bushing with a fluid lubricant. The bearing journals are separated by a recess having a vent passage between the recess and hollow center. A screw is threaded through the base plate or cover into the threaded end of the support shaft, mounting the support shaft to the base plate or cover. An air vent passage, such as a slit is provided axially either in the threaded end of the hollow center of the support shaft or in the screw, and radially across the end of the support shaft so the air bleed passage extends from the hollow center externally of the support shaft.

Fluid spindle bearing vent

An ink jet printing head comprising a head body made from a material having high specific stiffness and the head body includes an ink passage which is kept small to retain the high body stiffness. The ink passage comprises a narrow slot connected with internal holes in the body which lead to ink inlet and exit ports. A nozzle plate having a plurality of orifices is fixed to the front of the head body and a piezoelectric crystal is fixed to the back of the head body. The piezoelectric crystal is kept thin compared to the head thickness, typically on the order of 1/20 to 1/30 of the body thickness, so that the effect of the crystal on the resonant characteristics of the assembly is kept small. The ink jet head provides a plurality of columns or jets of ink which are excited in such a way as to break up into uniformly and equally spaced drops at a fixed distance from the nozzle plate containing the orifices which produce the jets.

Ink jet printing head

A pressurized fluid issuing from a nozzle orifice to form a jet stream is perturbated by a hybrid velocity and pressure modulation to form a stream of drops. A perturbation means, such as a piezoelectric crystal, is mounted both to vibrate the nozzle for modulating the stream velocity and to perturbate the interior volume of a fluid cavity communicating with the nozzle for also modulating the pressure of the fluid.

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San Jose, CA, United States of America

Chen-Hsiung Lee