Source: http://www.google.com/patents/US4894738?dq=7,003,515
Timestamp: 2014-11-26 16:15:18
Document Index: 700368494

Matched Legal Cases: ['art 25', 'art 89', 'arts 48', 'art 89', 'art 89', 'art 105', 'art 105', 'art 159']

Patent US4894738 - Disk storage drive - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsA disk memory drive includes a brushless drive outer rotor motor having an internal space and a stator with windings. The outer rotor coaxially encircles the stator and a substantially cylindrical air gap is defined between the stator and the rotor. The rotor includes permanent magnets and a hub fixedly...http://www.google.com/patents/US4894738?utm_source=gb-gplus-sharePatent US4894738 - Disk storage driveAdvanced Patent SearchPublication numberUS4894738 APublication typeGrantApplication numberUS 07/201,736Publication dateJan 16, 1990Filing dateJun 2, 1988Priority dateSep 7, 1981Fee statusPaidAlso published asUS4658312, US4843500, US5001581, US5006943Publication number07201736, 201736, US 4894738 A, US 4894738A, US-A-4894738, US4894738 A, US4894738AInventorsDieter Elsasser, Johann von der Heide, Heinrich CapOriginal AssigneePapst-Motoren Gmbh & Co. KgExport CitationBiBTeX, EndNote, RefManPatent Citations (1), Referenced by (17), Classifications (51), Legal Events (7) External Links: USPTO, USPTO Assignment, EspacenetDisk storage driveUS 4894738 AAbstract A disk memory drive includes a brushless drive outer rotor motor having an internal space and a stator with windings. The outer rotor coaxially encircles the stator and a substantially cylindrical air gap is defined between the stator and the rotor. The rotor includes permanent magnets and a hub fixedly connected with the magnet. A disk mounting section is provided on the hub for accommodating at least one storage disk positioned in a clear space, the mounting section being adapted to extend through a central aperture of the storage disk. The windings and the magnets interacting with the windings are disposed for at least half of the axial longitudinal dimension thereof within a space surrounded by the disk mounting section of the hub. Bearings rotatably mount the rotor and the hub.
What is claimed is: 1. A disk memory drive comprising: a brushless drive motor having an internal space defined therein and a stator including winding means defining magnetically active parts of the drive motor and having a given axial extension, the motor having an outer rotor with an open end coaxially encircling the stator and a substantially cylindrical air gap defined between the stator and the rotor, the rotor including a hub and including permanent magnet means having a predetermined axial extension fixedly connected therewith for magnetic interaction with said winding means; a disk mounting section provided on the hub for accomodating at least one storage disk located in a clean chamber surrounding said rotor, the mounting section along its axial length being adapted to extend through a central aperture of the storage disk, the winding means and the magnet means interacting therewith being disposed for at least half of the axial extension thereof within a space surrounded by the disk mounting section of the hub; and upper and lower bearing means having inner and outer races on a stationary shaft rotatably mounting the rotor and the hub on the shaft, the rotor also including rotational position indicator means interacting with stationary rotational position sensor means for determining the rotational position of the rotor, the internal space of said motor, which includes the internal portions thereof with the bearing means, being sealed off against the clean chamber containing the disk, and a disk-shaped ring member being located with precision at the open end of the rotor between the inner circumference of the rotor and the outer race of the lower bearing means.
2. A disk memory drive according to claim 1, wherein the rotational position indicator means includes permanent magnet poles disposed on the disk-shaped ring member for rotation therewith and wherein the rotational position sensor means is sensitive to magnetic fields and interacts with the permanent magnet poles.
3. A disk memory drive according to claim 1 wherein the rotational position sensor means is mounted on a printed circuit board opposite the disk-shaped member ring.
5. A disk memory drive according to claim 3, wherein the printed circuit board is supported on a flange fixed on the stationary shaft.
6. A disk memory drive according to claim 1, further including a magnetic shield means at least circumferentially surrounding the stator for shielding a clean chamber containing the disk from the magnetic flux of the stator and wherein the stationary shaft is of constant diameter and the outer rotor includes a bell-shaped housing with a substantially closed end and a substantially open end, the stator together with the magnetic shield being firmly mounted to the stationary shaft, the inner race of each bearing being firmly mounted on the stationary shaft on either axial side of the stator, the upper bearing being positioned inwardly adjacent of the closed end of the bell-shaped outer rotor, and the lower bearing being positioned adjacent the open end of the bell-shaped outer rotor.
7. A disk memory drive according to claim 1, wherein the internal space of the motor is sealed by means of a cover located at the open end of the outer rotor, the cover also serving as a bearing mounting flange, and the rotational position indicator means being mounted on the outside of the motor cover with respect to the sealed inner space of the motor.
8. A disk memory drive according to claim 1, wherein the outer rotor includes an outer rotor casing of ferrmomagnetic material, the outer rotor serving also as the hub, the rotational position indicator being mounted on a lower part of the hub outside the sealed inner space of the motor.
9. A disk memory drive according to claim 1, wherein further comprising a bearing mounting flange having projections in the actual axial direction that project into the disk-shaped ring member, and a labyrinth seal located between the projections and the ring member formed by a combination of cylindrical and radially flat gaps having only dimensions of normal clearances between moving parts.
12. A disk memory drive having having a brushless drive motor, comprising a stator having a predetermined axial extension, a coaxially positioned outer rotor and circling the stator and defining therebetween a substantially cylindrical air gap, the rotor having a predetermined axial extension, a cylindrically shaped permanent motor magnet disposed adjacent the air gap on the inner circumference of the rotor to rotate therewith and magnetically interact with the stator, a hub on the outer circumference of the rotor firmly fixed to the motor magnet, the hub being provided on its outer circumference with a disk mounting section which extends through the central opening in a storage disk to mount the disk and allowing at least one storage disk to be accommodated thereon, a clean chamber surrounding the disk mounting section to contain the mounted disk therein, at least half of the axial extension of both the stator winding and of the motor magnet interacting therewith being positioned within the space encompassed by the disk mounting section of the hub, a stationary shaft having upper and lower bearing means mounted thereon for rotatably mounting the rotor with hub on the shaft, and seals located axially above the upper and below the lower bearings for sealing the space therebetween from the outer clean chamber.
13. The disk memory drive according to claim 12, wherein the seals are magnetic liquid seals.
14. A disk memory drive according to claim 12, wherein the stationary shaft projects axially externally of the upper and lower seals.
15. A disk memory drive according to claim 12, wherein the seals are labyrinth seals.
16. A disk memory drive according to claim 15, wherein the labyrinth seal is formed of a member having a substantially L-shaped cross section being mounted on and extending radially from the stationary shaft, the short leg of the L-shaped member extending axially outwardly.
17. A disk memory drive according to claim 15, further including a ring member of L-shaped cross section being provided on the rotor and being opposite and complementary to the stationary mounted L-shaped member, the longer leg of the L-shaped member on the rotor extending inwardly toward the stationary shaft with only a clearance dimension separating the two parts.
18. A disk memory drive according to claim 15, wherein the stationary L-shaped member lies inboard axially and is substantially encompassed by the rotating L-shaped ring, a flat radial labyrinth gap being formed radially between the respective short legs of the L-shaped members.
BACKGROUND OF THE INVENTION This application is a continuation-in-part of application Ser. No. 038,049, filed Apr. 14, 1987, which is a continuation-in-part of application Ser. No. 767,671, filed Aug. 21, 1985, now U.S. Pat. No. 4,658,312, issued Apr. 14, 1987, which is a continuation of application Ser. No. 412,093, filed Aug. 27, 1982, now abandoned.
The bearing support ring can be prefabricated component provided with recesses for the passage of the electric leads and connections. Alternatively, the aforesaid connections can be potted in situ inside the bearing support ring.
FIG. 7 is is a section similar to FIG. 6 of a modified embodiment of the invention;
FIG. 12 is a partial section similar to but yet a variant of FIG. 7 of yet another embodiment of the invention having the rotational position sensor device located outside the sealed internal space of the motor.
Disk storages are most usually operated in "clean chamber" environments to protect them against contaminants. By means of the assembly flange 24, the storage drive is arranged on a partition (not shown) which separates the ultra-clean area for receiving the storage disks from the remainder of the interior of the equipment. Dirt particles, grease vapors and the like from bearing 52 and parts of the driving motor 45 are prevented from passing into the storage disk receiving area by labyrinth seals 90 and 91. The labyrinth seal 90 is formed in that the end of the bearing tube 50 away from the assembly flange 24 that projects into an annular slot 87 on the inside of the storage disk receiving part 25, accompanied by the formation of sealing gaps. Similarly, for forming the labyrinth seal 91, the end of the shield can 26 projects into the annular slot 88 of the assembly flange 24. The labyrinth seals 90, 91 are preferably dimensioned in the manner described in the aforementioned Patent No. 4,438,542.
The embodiment of FIG. 3 differs from the arrangement according to FIGS. 1 and 2 in that storage disks having the same opening diameters are placed on bearing webs 79 of a storage disk receiving part 89, which surrounds the majority of the axial dimension of the magnetic shielding can 26. In other words, the magnetically active parts 48, 49, 69 of the driving motor 45 are partially located within the central opening of the storage disk. A bush-like hub 98 is pressed or cast into the storage disk receiving part 89. The rotor shaft 46 is then pressed into the hub 98. The edge of the WE central opening 29 in the bottom 28 of the shielding can 26 extends up to the portion 99 of the receiving part 89 which received the hub 98.
FIG. 4 shows an embodiment in which a storage disk receiving part 105 is axially extended in order to be able to house a larger number of storage disks than in the arrangement of FIG. 3. The bearing tube 50 is correspondingly axially extended in order to be able to use the existing installation space with a view to a maximum axial spacing between the bearings 52 and 53. The end of the bearing tube 50, remote from as assembly flange 106, embraces the hub 98 connecting the receiving part 105 and the shaft 46, accompanied by the formation of a labyrinth seal 107. The edge of the central opening 29 of shielding can 26 extends up close to the outside of the bearing tube 50. The free end of the shielding can 26 engages a recess 108 in the assembly flange 106. As a result, a further labyrinth seal 109 is formed. This embodiment otherwise corresponds to the structures already described herein.
In FIGS. 5 and 6, a brushless drive motor, designated as 110 has a stator 111 with a stator lamination stack 112. The stator lamination stack 112 is arranged radially and symmetrically with respect to a central axis of rotation 113 and forms six stator poles 114A to 114F in an essentially T-shaped configuration as seen from above in accordance with FIG. 5, which poles are positioned at regular angular intervals of 60'. Instead of one lamination stack, for example, a sintered iron core can also be provided. Pole shoes 115A to 115F, together with a permanent magnetic rotor magnet 116 define an essentially cylindrical air gap 117. The rotor magnet 116 is radially magnetized in four poles around its periphery as indicated in FIG. 5; that is to say, it has four sections 118A to 118D, and, on the internal side of the annular rotor magnet 116 toward the air gap 117 there are positioned, in alternating sequence, two magnetic north poles 119 and two magnetic south poles 120. The poles 119, 120 have, in the example depicted, a width of substantially 180-el (corresponding to 90 mechanical). Thus, in the circumferential direction of the air gap 117, an approximately rectangular or trapezoidal magnetization is obtained. The rotor magnet 116 is mounted, typically by bonding, in an outer rotor casing or bell 121 of soft magnetic material, preferably steel, which serves both as a magnetic return path and as a magnetic shield. The casing 121 and the magnet 116 together form an external rotor 122. The rotor magnet 116 can include in particular a rubberized magnetic unit, or a plastic-bound magnet. Instead of a single-piece magnetic ring, curved magnetic segments can also be bonded or otherwise attached in the casing 121. Magnetic materials made from synthetic bonding compounds, a mixture of hard ferrite and elastomers, ceramic magnetic materials or samarium cobalt are all particularly suitable as materials for the magnetic ring or segments.
In a central aperture 137 of a frontal wall 138 of the hub 132, which is relatively heavy for reasons of stability, are a ball bearing 139 and a magnetic fluid seal 140 on the side of the support which is axially oriented away from the drive motor 110. The seal 140 consists of two annular pole pieces 141, 142, a permanent magnet ring 143 located between both these pole pieces, and a magnetic fluid (not shown), which is inserted into an annular gap 144 between the magnetic ring 143 and a stationary shaft 145. Seals of this type are known under the designation of "Ferrofluidic Seal". An internal space 146 is located within the motor and is sealed on the side of the space oriented away from the frontal wall 138 by means of a motor cover 147, which is inserted into the outer rotor casing 121 and the hub 132, by means, for example, of adhesion. The internal space 146 includes the internal parts such as the stator 111 and permanent magnet 116 as well as bearings 139 and 149. The motor cover 147 abuts with its cylindrical outer edge 247 the lower edge of the rotor casing 121. This allows a particularly easy assembling of the cover 147 within the hub 132. For sealing purposes, adhesive material 190 is placed in a circumferential groove 191 between the cover 147 and the hub 132.
In a further modified embodiment shown in FIG. 7, the rotor magnet 116 is located directly with the hub 132�, which itself forms the magnetic shield, and is made of magnetically conductive material, preferably soft iron. The control magnet ring 152' is located on the frontal side of the flange 133 facing away from the disk mounting section 131 of the hub 132�, and alternately magnetized in the axial direction. In this embodiment, the rotational position sensors 156, 157, 158 are axially opposed to the control magnet ring 152'. The magnetic fluid seal 150 ensures, together with a labyrinth seal 165 which replaces the magnetic fluid seal 140 of the embodiment in FIG. 6, the sealing of the internal space 146, including the bearings 139, 149 reative to the clean chamber 148. The connections of the stator winding 166 are conducted through the bores 162, 163 of the stationary shaft 145. It should be understood that, even in this embodiment, the rotational position sensors 156, 157, 158, can, if desired, be accommodated by a common support corresponding to the molded part 159 (FIG. 14), which support is attached to the printed circuit board 155.
FIG. 14 is a variant of FIG. 6 primarily in the provision of the groove 151 in the motor cover 147 which receives the magnet ring 152 and allows the rotational position sensor 156 to face the magnet ring across a cylindical air gap vis-a-vis a planar gap in the embodiment shown in FIG. 6.
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS4739427 *Jan 14, 1987Apr 19, 1988Micropolis CorporationHigh capacity hard disk construction* Cited by examinerReferenced byCiting PatentFiling datePublication dateApplicantTitleUS5280207 *Mar 10, 1992Jan 18, 1994Nippon Densan CorporationSpindle motor with disk clamping arrangementUS5305163 *Mar 2, 1993Apr 19, 1994Seagate Technology, Inc.Stationary angularly aligned stationary spindle shaftUS5319270 *May 30, 1991Jun 7, 1994Mitsubishi Denki Kabushiki KaishaElectric motorUS5347189 *Sep 25, 1992Sep 13, 1994Nippon Densan CorporationSpindle motor with labyrinth sealed bearingUS5381066 *Feb 25, 1993Jan 10, 1995Nippon Densan CorporationSpindle motor with a sealing memberUS5552650 *Feb 25, 1994Sep 3, 1996Papst Licensing GmbhDisk storage device with motor with axially deep flangeUS5596235 *Feb 17, 1994Jan 21, 1997Nidec CorporationSpindle motor with seal structureUS5606473 *Sep 21, 1995Feb 25, 1997Seagate Technology, Inc.Unitary rigid and flexible circuit package for disk drivesUS5821646 *Jul 1, 1996Oct 13, 1998Nidec CorporationSpindle motor with seal structureUS5859745 *Nov 2, 1993Jan 12, 1999Seagate Technology, Inc.Data storage apparatusUS5940247 *Mar 26, 1997Aug 17, 1999International Business Machines CorporationMagnetic recording device with spindle motor lubricant of specified amine and carbamate concentrations/ratiosUS5949164 *Aug 20, 1997Sep 7, 1999Papst Licensing GmbhDisk storage device with electric motor with axially deep flangeUS5982578 *Dec 13, 1996Nov 9, 1999Seagate Technology, Inc.Disk drive housing with recess for circuit panelUS6741007 *Jul 27, 2001May 25, 2004Beacon Power CorporationPermanent magnet motor assembly having a device and method of reducing parasitic lossesUS20120011522 *Jun 17, 2011Jan 12, 2012Samsung Electro-Mechanics Co., LtdMotor and optical disc drive using the sameUSRE37058Mar 4, 1997Feb 20, 2001Papst Licensing Gmbh & Co. KgDisk storage device having contamination sealsWO2008088412A1 *Oct 12, 2007Jul 24, 2008Dennis D Belden JrMagnetic shielding for display device* Cited by examinerClassifications U.S. Classification360/97.11, G9B/25.003, G9B/17.012, G9B/19.028, 360/99.08International ClassificationG11B25/04, G11B19/20, H02K11/00, G11B17/038, H02K5/22, H02K7/14, H02K3/28, H02K21/22, H02K5/10, H02K5/167, H02K5/124, H02K29/08, H02K5/173, H02K7/08Cooperative ClassificationH02K7/14, H02K29/08, G11B17/038, H02K3/28, H02K7/086, H02K5/1735, H02K7/085, H02K5/1737, H02K2211/03, H02K5/124, G11B25/043, G11B19/2009, H02K5/225, H02K11/0005, H02K21/22, H02K7/08, H02K5/10, H02K5/167European ClassificationH02K5/10, H02K29/08, G11B19/20A, H02K5/124, H02K7/08D, G11B25/04R, H02K7/08E, H02K11/00B, G11B17/038, H02K5/22B, H02K7/14, H02K21/22, H02K5/173E, H02K5/173DLegal EventsDateCodeEventDescriptionMay 14, 1999ASAssignmentOwner name: PAPST LICENSING GMBH & CO. KG, GERMANYFree format text: LEGAL ORGANIZATION CHANGE;ASSIGNOR:PAPST LICENSING GMBH;REEL/FRAME:009922/0250Effective date: 19981103Jul 22, 1997RFReissue application filedEffective date: 19970401Jul 7, 1997FPAYFee paymentYear of fee payment: 8Jul 14, 1993FPAYFee paymentYear of fee payment: 4Jun 10, 1993ASAssignmentOwner name: PAPST LICENSING GMBH, GERMANYFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:PAPST-MOTOREN GMBH & CO KG;REEL/FRAME:006573/0174Effective date: 19930526Mar 19, 1991CCCertificate of correctionAug 26, 1988ASAssignmentOwner name: PAPST-MOTOREN GMBH & CO. KG., ST. GEORGEN, BLACK FFree format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:ELASASSER, DIETER;VON DER HEIDE, JOHANN;CAP, HEINRICH;REEL/FRAME:004932/0658Effective date: 19880819RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services©2012 Google