Quantum Corporation

Western Digital (fremont), Inc.

Nec Corporation

Read Rite Corporation

Michael R Hatch

Chak M Leung

Yan Zang

Stephen Paul Williams

Ronald R Moon

Jwo-min Wang

Robert P Cloutier

William G Moon

Timothy A Riener

Daniel E Barnard

Shuo-Hao Chen

Joseph T Castagna

Stephen S Murray

Gregg J Uhlendorf

Klaus-Peter Deyring

Robert J Kobliska

Shinichi Minakuchi

Thomas J Huber

James A McDonald, Iii

Bryan T Silbermann

Willilam G Moon

Philip L Steiner

Shuhao Chen

Jon Edward Jacoby

Chee K Han

James Montgomery Low

A magnetic head suspension assembly is fabricated with an integral piece which includes a load beam section, a flexure section, a rear mount section and a leaf spring section between the load beam and rear mount. A tongue extends from the load beam to the flexure and has a down-facing load dimple which contacts the non-air bearing surface of an attached air bearing slider. The flexure includes narrow thin legs adjacent to a cutout that delineates the load beam tongue. The head suspension is characterized by a high first bending mode frequency and low pitch and roll stiffness.

Magnetic head suspension assembly fabricated with integral load beam and flexure

A magnetic head suspension assembly is fabricated with an integral piece which includes a load beam section, a flexure section, a rest mount section and a leaf spring section between the load beam and rear mount. A tongue extends from the load beam to the flexure and has a down-facing load dimple which contacts the non-air bearing surface of an attached air bearing slider. The flexure includes narrow thin legs adjacent to a cutout that delineates the load beam tongue. The head suspension is characterised by a high first bending mode frequency and low pitch and roll stiffness.

A method corrects track misregistration attributable to out-of-plane motions of a rotating disk in a hard disk drive, and includes the steps of measuring a base plate-roll-bias angle between the rotating data storage disk and the head arm with a precision measuring device, and connecting the head arm and load beam at a roll-bias angle selected to minimize track misregistration attributable to the roll-bias. A number of connection arrangements and structures are presented in order to achieve the desired reduction in track misregistration.

Roll-biased head suspension for reduced track misregistration

A self-contained hydrodynamic bearing unit with improved sealing and performance is disclosed. Centrifugal capillary seals are angularly defined between an outwardly tapered outer surface of a top screw and an inwardly tapered inner surface of an annular clamp ring at the top of the bearing unit as well as between an outwardly tapered outer surface of a seal plate and an inwardly tapered inner surface of an annular clamp ring at the bottom of the bearing unit. During operation, bearing lubricant is pumped away from the seal opening and toward the bearings by centrifugal force at the seals, providing dynamic sealing. When the bearing unit is not rotating, capillary forces retain the lubricant within the seal, preventing the lubricant from leaking. The tapered configuration of the seals also shortens the vertical seal length for a given effective seal length, thereby maximizing the journal bearing length/span and improving dynamic performance of the bearing unit.

Hydrodynamic bearing unit

An optimized bump and offset along the spring section of a load beam of a head-gimbal assembly ('HGA') in the loaded state redistributes the mass and stiffness distributions of the load beam from a truly flat state, so that the mode shape of the first torsional resonance mode is changed such that the coupling between a drive actuator head arm and the head slider is essentially eliminated. A fabrication method to produce the desired bump and offset, and a characterization method to ascertain that optimized bump and offset parameters have been achieved are also disclosed. By optimizing bump and offset, the slider remains independent from any load beam first torsional vibration even at resonance and/or sway mode resonant frequency of the HGA may be increased.

Load beam having tuned resonance mode performance for supporting a

A self-contained hydrodynamic bearing unit includes a shaft having a threaded axial opening at one end thereof and a shaft shoulder adjacent the opening and perpendicular with a longitudinal axis of the shaft, a sleeve defining an opening for receiving the shaft for relative rotation, a pair of longitudinally spaced-apart radial hydrodynamic journal bearings defined between the shaft and the sleeve, a shaft-bolt including a threaded end region for mating with the threaded axial opening of the shaft and defining a bolt shoulder, an annular thrust plate having two parallel radial faces and adapted to fit upon the shaft-bolt for mounting between the shaft shoulder and the shaft bolt shoulder when the shaft-bolt is mated with the threaded axial opening of the shaft, the sleeve defining a radial thrust bearing surface portion extending radially outwardly at one end and positioned to confront one radial face of the thrust plate, an annular thrust bushing mounted to the sleeve and defining a radial thrust bearing surface portion confronting the other radial face of the thrust plate, the annular thrust plate defining two axial hydrodynamic thrust bearings respectively with the radial thrust bearing surface portion of the sleeve and the radial thrust bearing surface portion of the annular thrust bushing and a hydrodynamic thrust bearing lubricant reservoir between the two axial hydrodynamic thrust bearings and between a cylindrical face of the thrust plate and a facing cylindrical wall of the sleeve, and a hydrodynamic bearing lubricant in the bearing unit and at the pair of hydrodynamic journal bearings and at the two axial hydrodynamic thrust bearings and in the hydrodynamic bearing lubricant reservoir.

Hydrodynamic bearing for spindle motor having high inertial load

A self-contained hydrodynamic bearing unit includes a shaft and a shaft housing defining an opening for receiving the shaft for relative rotation. The shaft and bearing define at least one radial hydrodynamic bearing and an annular thrust bearing, formed as a disk portion extending radially outward of a main cylindrical surface of the shaft which cooperates with an adjacent annular face of the shaft housing. A gap between an outer cylindrical wall of the thrust bearing disk portion and an adjacently facing cylindrical surface of the shaft housing provides a primary annular capillary seal segment. An annular bushing ring extends from the housing radially inwardly to enclose the thrust bearing disk, and cooperates with an adjacent outer face of the thrust bearing disk to provide a secondary containment capillary seal segment. Normally, lubricating liquid is in the bearing unit at the radial hydrodynamic bearing, at the hydrodynamic thrust bearing and in the primary annular capillary seal segment. However, if liquid overflows from, or extends beyond the primary seal segment as by thermal expansion, it is contained in the secondary seal segment and urged to return by centrifugal force to the primary seal segment. A tertiary containment seal may also be provided to prevent escape of liquid to the external ambient.

Self-contained hydrodynamic bearing unit and seals

A method and apparatus for sensing vibration in a flex circuit located between a rotary actuator and electronics within a disk drive. Specifically, the apparatus contains a strain gauge attached to or imbedded within the flex circuit. The resistivity of the strain gauge varies in response to vibrations on the cable. This resistance variation can be transformed into electrical signals that are used by a servo system to move the actuator assembly in compensatory motion that effectively cancels any off-track motion caused by the vibrations.

Flex circuit vibration sensor

Method for characterizing and controlling in-plane stiffness of load

A hydrodynamic bearing unit includes a shaft, a sleeve rotatably disposed over the shaft and defining a plurality of spaced-apart hydrodynamic journal bearings, an annular axial thrust plate secured to the shaft to form a shaft subassembly and having a first radial surface in facing confrontation with a shoulder of the sleeve and defining a first hydrodynamic thrust bearing, a thrust bushing secured to the sleeve to form a sleeve subassembly and having a bearing surface in overlying facing engagement with a second radial surface of the annular axial thrust plate to form a second hydrodynamic thrust bearing, a seal for hydrodynamic lubricant defined within an annular Vee groove located adjacent to the shaft and having an apex converging toward the second hydrodynamic thrust bearing, a motor for rotating the sleeve subassembly relative to the shaft subassembly, and hydrodynamic lubricant within the annular Vee groove, the lubricant being retained in place by capillary force in the absence, of rotation, and by centrifugal force in the presence of relative rotation between the subassemblies. A secondary seal is also described.

Hydrodynamic bearing and seal

When a rotary-actuator voice coil type disk drive is powered down the actuator arm is moved to a parking position against an I.D. stop by a disk spindle motor back EMF, resulting from the spinning down of the spindle motor. Current is applied by the back EMF through a delay circuit to a latch arm voice coil on one end of a latch arm and forming part of a magnetic circuit including a drive permanent magnet on a ferrous base plate and a ferrous upper plate. Resultant movement of the latch arm overcomes a spring bias of a torsion spring extending between the base plate and pivoted latch arm normally keeping the latch arm in an unlatched position. A latch permanent magnet extends from the other end of the latch arm and is brought into spaced proximity, but not contact, with a ferrous member extending from the actuator arm so that the magnetic force therebetween holds the actuator arm against the I.D. stop in latched position to withstand high shock loadings. Powering the rotary actuator voice coil motor up overcomes the magnetic force and allows the biased torsion spring to move the latch arm to the unlatched position without resultant loss of data storage area.

Active magnetic latch for disk drive and method

A magnetic head suspension assembly is fabricated with a load beam formed with a central triangular-type major section, a tongue section at the front end and a rigid mount section at the opposing rear end. The load beam has flanges along the sides of the central major section and the rear mount section. A leaf spring is provided between the central major section and the rear mount section for providing flexibility to the suspension. A flexure that is joined to the load beam is formed with a U-shaped finger surrounded by a cutout at the front end of the flexure. A load dimple that is provided on the flexure is in contact with the load beam. The flexure supports an air bearing slider that pitches and rolls relative to a disk surface. The flexure does not extend beyond the load dimple of the flexure or the front leading edge of the slider. The suspension is characterized by a high first bending mode frequency and low pitch and roll stiffness.

Magnetic head suspension assembly

A hard disk drive for a computer system including a head disk assembly with a disk platter of approximately one-and-eight-tenths-inch in diameter capable of storing more than forty megabytes. In an embodiment, data tracks on each data surface of the platter are spaced at approximately 2,558 tracks per inch and each data track has approximately 36,000 flux changes per inch. An actuator positions a pair of read/write heads on each platter surface using a voice coil motor to position the heads over a cylinder. A magnetic actuator latch attaches to another magnet on the actuator and locks the heads in a parked position at the innermost diameter of the platter. A spindle motor rotates the platter at approximately 5,400 revolutions per minute. A base plate, with a gasketed surface and a raised lip, hermetically seals with a cover to the base plate such that the platter, the actuator, the actuator latch, and the spindle motor are all contained within. The cover carries a breather filter and recirculating air filter. The raised lip on the base plate prevents direct electrical interference from passing between the base plate and the cover.

Growing community of inventors

Mountain View, CA, United States of America

Michael R Hatch