Seagate Technology Incorporated

Wesley R Clark

David John Jennings

Roger Allen Addy

Hans L Leuthold

Norbert Steven Parsoneault

Raquib Uddin Khan

Michael David Kennedy

Matt L Shumway

Ronald Thomas Albo

Alan Lyndon Grantz

Alan Lydon Grantz

Lakshman Nagarathnam

Klaus Dieter Kloeppel

Gunter Karl Heine

Mohamed Mizanur Rahman

Donald J MacLeod

Samnathan Murthy

Coda H Pan

Guenther Heine

Etoli Wolff

Gunther Heine

To simplify fabrication of an integral hub piece, the opening between the upper and lower female cones in this hub has sufficient width or radial dimension to allow access to both cones from one side of the hub with the cutting tool. A cutting tool is used which has a width smaller than the opening between the cones. Preferably, the tool has a width which is about equal to or smaller than an angular dimension through this opening which is defined by extending surfaces of the upper and lower female cones. If this limitation is satisfied, both cones can be created with a single machine set up operating from one side of the integrated hub.

Single piece hub with integral upper and lower female cones

Methods of machining a single piece hub with integral upper and lower female cones includes providing a single piece hub with upper and lower conical voids having respective narrow ends proximal each other and respective wide ends distal each other. Surfaces of the voids are machined using a tool provided from a single side of the hub that is dimensioned to fit through an opening defined by the interface between the narrow ends of the conical void. The tool can be moved parallel to a rotational axis for accessing conical surfaces of both voids and perpendicular to the rotational axis while contacting the surfaces so as to produce a final machined surface.

Method of forming a hub for use in a disk drive motor

Single piece hub with integral upper and lower female cones and method for making the same

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

Apparatus for defining patterns electrochemically on conductive materials by forming the patterns as conductive features of a tool, providing insulative properties about the conductive features so the patterns are defined; then providing an immersive medium including an etchant or plating material for defining the pattern on a workpiece, providing an electric direct current so that the immersive medium is concentrated at desired locations defined by the conductive features on the conductive materials; and etching the conductive materials by applying the electric current in a quantity and for an elapsed time to etch or plate patterns in or on the conductive materials.

Electrode design for electrochemical machining of grooves

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

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 bimetallic part is formed from metals or comprises metals with different thermal expansion coefficients. A first element defines the part and defines one surface of the bearing gap and has a first coefficient of expansion and a second element is wholly or partially inserted into and constrained within the first element and having a different coefficient of thermal expansion so that as the temperature changes, the stress created by the differential expansion of the two elements will cause the overall part to deform elastically as a function of temperature. This deformation will cause the gap, the elements being properly selected, to narrow as temperature rises (and viscosity falls) and to widen as temperature falls (and viscosity rises).

Thermal compensation for fluid dynamic bearing using bimetal parts

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

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

Grooved hydrodynamic thrust bearing

The present invention includes four sections or partitions: two thrust bearings which are formed by the sides of a grooved thrust plate and corresponding countersurfaces, the thrust bearings designed to cause fluid flow in a single direction up around the rotating thrust plate and upward along the surface of a rotating journal, and two journal bearings formed side-by-side on the journal formed between a rotating shaft and a bushing with multiple spiral-grooved sections being formed on the rotating shaft or in the stationary bushing. The two journal bearings are separated by a circumferential groove in the shaft which is connected by a radial bore to a hollow reservoir in the shaft for providing fluid to the journal bearing and the thrust bearing. By providing this bore and a second bore located near to the thrust bearing, the boundary conditions for the combined journal bearings and thrust bearings are fixed and a stable rotating shaft is achieved.

Single plate hydrodynamic bearing with self-balancing fluid level and

A magnetic disc storage system includes a base and a rotating magnetic disc having an axis of rotation. A transducing head which reads and writes information is positioned proximate the disc. The disc rotates on a rotating member relative to a fixed member which is attached to the base. In one embodiment, the hydrodynamic bearing has a shape which forms a portion of a sphere.

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Watsonville, CA, United States of America

Wesley R Clark