Seagate Technology Incorporated

David John Jennings

Hans L Leuthold

Wesley R Clark

Lakshman Nagarathnam

Gunter Karl Heine

Raquib Uddin Khan

Norbert Steven Parsoneault

John W Elsing

Roger Allen Addy

Samnathan Murthy

Dean Albert Tarrant

Steve G Gonzalez

Coda H Pan

Guenther Heine

Alan Lyndon Grantz

Robert Michael Pelstring

Donald J MacLeod

Gregory I Rudd

Stanislaw Dobosz

Hany Michael Gross

Gordon A Harwood

Steve Parsoneault

Gunther Heine

Gerold Heiner

Greg Rudd

Jeffery A LeBlanc

Lakshman Nagarathman

Martin F Byl

Described are electronic hard disk drives that are made to include: a base; a cover; interior components such as a stack of magnetic recording disks, reading and recording heads, electronics to read and record and to transfer data to and from an external electronic device; and a cover support at the interior of the device to inhibit movement of the cover.

Hard disk drive with cover and cover support

A hydrodynamic spindle motor including an internally disposed heating element in a stationary spindle portion having a spindle hub rotatably coupled thereto. The hydrodynamic spindle motor has particular application for supporting discs for co-rotation for a disc drive. The heating element is activated to control viscosity of a hydrodynamic fluid of a hydrodynamic bearing rotationally supporting the spindle hub relative to the stationary spindle. Operation of the heating element reduces viscosity of the hydrodynamic fluid to reduce motor power requirements and improve &ldquo;up-to-speed&rdquo; time.

Hydrodynamic spindle motor with an internally disposed heating element

Hydrodynamic bearing having a shaft relatively rotatable with respect to a surrounding sleeve and having a thrust plate on one end thereof rotating in a recess of the sleeve. The shaft is preferably interrupted by a equi-pressure groove accessing a central reservoir in the shaft and having journal bearings defined by herringbone patterns above and below the groove to stabilize and provide stiffness to the cartridge. The stiffness of the cartridge is further enhanced by a thrust plate carried at one end of the shaft and rotating in a recess of the sleeve and being used to define thrust bearings on either surface thereof.

Single plate hydrodynamic bearing cartridge

A gap setting apparatus incorporates an air gage to measure the pressure drop (and indirectly the flow rate) of air through a gap of a hydrodynamic bearing, while facing sections of the bearing are moved closer together. The measured pressure drop can be correlated to the actual bearing gap and monitored to determine when the proper gap has been achieved. More particularly, the inner and outer elements of the bearing are clamped in separate carriers and are held in place. The carriers are then moved toward one another so that the inner or shaft portion of the bearing slides into the outer or sleeve portion of the bearing. To accurately set the gap between the two, an air hose with an air gage attached to it is attached to one end of the bearing gap; air is pumped through the bearing gap, exiting through the opposite end of the gap, By testing a set of reference motor parts, a high end and a low end of an acceptable bearing gap range can be established, and the corresponding air gage readings obtained. Thus, once the air gage has been calibrated against a minimum and maximum gap, each motor can be assembled with the proper gap by simply adjusting the relative position of the parts until a target air gage reading or a reading between the high and low end of an acceptable range is obtained.

Apparatus for setting gaps in hydrodynamic bearing

This invention deals with compensating for thermal changes such that the spindle motor bearing preload remains as constant as possible throughout the disc drive operational temperature range. This is achieved by selecting a combination of materials with a composite thermal expansion that offsets the differential expansion of the steel bearing supports and the ceramic balls. The change in materials and configuration can be either that of the shaft, the hub, the support members, or any combination thereof.

Thermal compensation spindle for ceramic ball bearings

According to the present invention spindle bearings are assembled with at least one annular gimbal to compensate for undesired components of bearing compression force. Specific devices and methods are directed to compensating for either (a) operational force variations such as those caused by temperature variation or (b) assembly-related force variations such as those caused by misalignment.

Annular gimbal assembly suitable for disc drive spindle bearings and method of making same

A spindle motor is described having a motor stator, a motor rotor, the motor being energized to cause rotation of the rotor supporting a single disc or a stack of discs which is mounted in such a way that the rotating bottom or top (or both) disc surface is closely adjacent to a stationary disc drive casting surface. The squeeze film action in the remaining air gap provides significant damping of the disc vibration. Typical implementation use air gaps of 0.004&Prime;-0.006&Prime; for 2&frac12;&Prime; drives and 0.006&Prime;-0.10&Prime; for 3&frac12;&Prime; drives.

Squeeze film damping for a hard disc drive

A method for setting a gap at or near an optimum width in a hydrodynamic bearing defined between a shaft having end pieces, the end pieces having axially opposing exterior sides which are not parallel, the end pieces being adjustable axially, and a surrounding sleeve comprising independently supporting the shaft and the sleeve to be capable of finely positioned relative motion, in which adjustment is accomplished by moving the shaft and the sleeve together to form the gap with respect to the end pieces and the sleeve and supplying pressurized air to an opening to the gap to cause air to flow through the gap, while monitoring an air pressure drop due to the air flow through the gap while the end pieces are adjusted.

Air gaging for setting gaps in hydrodynamic bearings

A hydrodynamic bearing design is disclosed incorporating a flexible membrane at one end of the fluid gap in the hydrodynamic bearing. If voids exist in the fluid, and if changes in the size of these voids or bubbles occur with changes in temperature or pressure in which the disc drive is being used, then the volume of the fluid will change, and increase relative to the change in size of the volume of the surrounding physical part. The flexible membrane will yield to the increased pressure of the increasing volume of the fluid. The membrane essentially acts as a spring whose spring force is overcome by the pressure created by or accompanying a increase in volume in which the lubricating fluid is contained, and preventing its escape or being forced out of the inner region of the bearing.

Fluid retention principle for hydrodynamic bearings

A thrust plate with grooved surfaces within a hydrodynamic bearing establishes pressure gradients which cause the lubricating fluid for the bearing to reliably remain within the region of the hydrodynamic bearing, with the pressure gradient imposed on the fluid causing the fluid to flow toward the center of the bearing rather than to be caused to be forced outward toward the far end of the bearing which could potentially result in a leakage of the fluid.

Single plate hydrodynamic bearing with self-balancing fluid level

An apparatus for forming grooves in the surface of an article is disclosed. The apparatus includes a cage which has a circular cage wall with an annular pattern of holes in the wall. The apparatus also includes a plurality of spherical balls, each rotatably disposed in a respective hole of the cage wall and has a diameter greater than the wall thickness. The apparatus further includes a pin located within the cage, the pin has a circumferential groove in a plane coincident with the plurality of spherical balls and holes in the cage wall so that the pin holds the balls in the groove, the balls protruding through the cage wall and engaging the surface of a workpiece to be grooved so that the balls roll in the groove in the pin and, with movement of the workpiece and the apparatus, cause grooves to be formed in the interior surface of the workpiece. Lastly, the apparatus further includes an object at either end of the pin for holding the pin against translational movement relative to the cage with movement of the apparatus and the workpiece so that only a rotational movement is imparted to the pin by rotation of the workpiece.

Device for manufacturing a groove bearing

Disc drive spindle motor having hydro bearing with optimized lubricant

Sinusoidal grooving pattern for grooved journal bearing

For a precision spindle motor, an invention for reducing distortion resulting from interference fits of a thrust plate to spindle motor shaft and of a counter plate to a journal. A method of assembly according to the invention includes the step of balancing an interference pressure about a centerline of at least one of the thrust plate and the counter plate of the spindle motor. A precision spindle motor according to the invention comprises a journal having a bore defined therein, a shaft located in the bore, a thrust plate mounted to a top portion of the shaft by means of an interference fit, and a counter plate mounted to the journal adjacent to the thrust plate by means of an interference fit, wherein an interference pressure is balanced about a centerline of at least one of the thrust plate and the counter plate.

Low distortion interference fits for spindle motor assembly

The present invention replaces the current spindle motor ball bearing system of a hard disc drive by a system comprising three separate elements, including a self-pressurizing journal bearing for establishing radial stiffness which comprises a rotating shaft and sleeve with air or other fluid therebetween. A chevron or herringbone pattern is established on the sleeve or shaft to establish a self-pressurizing hydrodynamic bearing which maintains the stability of the system while providing for very simple manufacturing of the system. Additionally, a thrust bearing is defined based on the air pressure build-up between the housing for the disc stack and the disc stack itself. The term 'integrated air-bearing' is used to name this thrust bearing because it is built up with components such as discs and housing which exist in any typical hard disc assembly. The integrated air-bearing may be sufficiently established by building up the bottom surface of the housing or the base of the housing to within a very close distance of the lower surface of the disc; preferably, both the top surface of the top disc and bottom surface of the bottom disc are located close to pads, or other configurations are built up to define a narrow gap between the top and bottom surfaces of the disc stack and the housing. Third, an axial elastic thrust bearing defines the axial position of the disc stack at rests and avoiding contact between the surfaces forming the integrated air-bearing (in other terms, disc and housing). This elastic thrust bearing comprises a ball fixed to the shaft that rest against an elastic shield fixed to the end sleeve of the journal bearing or the base of the disc drive. This bearing defines the axial position of the disc stack.

Growing community of inventors

Santa Cruz, CA, United States of America

David John Jennings