Source: http://www.google.com/patents/US5774302?dq=6,563,928
Timestamp: 2014-10-25 01:04:21
Document Index: 509463515

Matched Legal Cases: ['art 25', 'art 25', 'art 25', 'arts 48', 'art 25', 'art 25', 'art 25', 'art 25', 'art 105', 'art 105', 'arts 113']

Patent US5774302 - Spin drive motor for a disk storage device - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsA disk storage drive for a disk storage device having a clean chamber for a storage disk having a central opening is provided with a brushless drive motor. The drive motor includes a stator and a winding on the stator and further includes a shaft aligned with the rotation axis of said motor, and a magnetically...http://www.google.com/patents/US5774302?utm_source=gb-gplus-sharePatent US5774302 - Spin drive motor for a disk storage deviceAdvanced Patent SearchPublication numberUS5774302 APublication typeGrantApplication numberUS 08/468,096Publication dateJun 30, 1998Filing dateJun 6, 1995Priority dateSep 7, 1981Fee statusPaidAlso published asUS5216557, US5422769, US5446610, US5557487, US5864443Publication number08468096, 468096, US 5774302 A, US 5774302A, US-A-5774302, US5774302 A, US5774302AInventorsDieter Elsaesser, Johann von der HeideOriginal AssigneePapst Licensing, GmbhExport CitationBiBTeX, EndNote, RefManPatent Citations (42), Non-Patent Citations (4), Referenced by (11), Classifications (60), Legal Events (6) External Links: USPTO, USPTO Assignment, EspacenetSpin drive motor for a disk storage deviceUS 5774302 AAbstract A disk storage drive for a disk storage device having a clean chamber for a storage disk having a central opening is provided with a brushless drive motor. The drive motor includes a stator and a winding on the stator and further includes a shaft aligned with the rotation axis of said motor, and a magnetically conducting member supported for rotation about the rotation axis and having an inner wall coaxially surrounding the stator. A magnet fixed to the inner wall of the magnetically conducting member is radially spaced from the stator. The disk storage device further includes a hub positioned within the clean chamber and contiguous with the magnetically conducting member so that the hub and the magnetically conducting member together form an outer rotor of the drive motor. The outer rotor has a radially extending flange having a surface which supports said storage disk. A support member contiguous with a portion of a partition of the clean chamber supports the shaft and has a recess receiving a portion of said radially extending flange, whereby the spacing between opposing walls of the clean chamber is reduced. Further, the magnetically conducting member comprises magnetic shield means at least peripherally surrounding the stator and at one end radially extending to the bearing and shaft assembly, and the rotor has a radially extending inner wall spaced closely adjacent to said stator windings, whereby said disk storage device is compact in a direction along said disk rotation axis while said motor magnet is axially separated from the plane of said storage disk.
What is claimed is: 1. A spin motor for rotating a storage disk in a disk storage device, comprising:a stator and a winding on said stator; an external rotor coaxially surrounding said stator and spaced therefrom by a substantially cylindrical air gap, said rotor having a permanent magnetic rotor magnet and a soft magnetic yoke, and a hub concentric to said yoke, said hub being connected to the rotor for rotation therewith and having a cylindrical disk support portion which can pass through a central opening of a storage disk for receiving at least one storage disk, said hub having an outwardly radially projecting flange at one axial extremity of said rotor; and a support member contiguous with the disk storage device for supporting said stator, said support member including a radially extending flange adjacent said axial extremity of said rotor, said support member flange having a recess cooperating with said outwardly radially projecting flange of said hub to allow said outwardly radially projecting flange to nest in said recess, thereby making the motor more compact. 2. The spin motor for rotating a storage disk in a disk drive according to claim 1, wherein at least part of the axial extent of said outwardly radially projecting flange of said hub is received within said recess.
3. The spin motor for rotating a storage disk in a disk drive according to claim 1, wherein said soft magnetic yoke has an outwardly radially projecting flange adjacent said outwardly radially projecting flange of said hub, and wherein said support member flange has a recess cooperating with said outwardly radially projecting flange of said yoke.
4. The spin motor for rotating a storage disk in a disk drive according to claim 3, wherein said soft magnetic yoke has an outwardly radially projecting flange adjacent said outwardly radially projecting flange of said hub, said outwardly radially projecting flange of said yoke being at least partly within said cooperating recess.
5. The spin motor for rotating a storage disk in a disk drive according to claim 3, wherein said flange of said hub has a circumferential wall that engages radially and externally over said flange of said yoke.
6. The spin motor for rotating a storage disk in a disk drive according to claim 3, wherein said recess cooperating with said flange of said hub is common with said recess cooperating with said flange of said yoke.
7. The spin motor for rotating a storage disk in a disk drive according to claim 1, wherein two recesses are formed in said support member flange and define a stepped surface in said support member flange.
8. The spin motor for rotating a storage disk in a disk drive according to claim 1, further comprising a bearing tube fixed to said support member flange.
9. The spin motor for rotating a storage disk in a disk drive according to claim 1, wherein the hub is composed of a material that is suitable after machining for clean area use.
10. The spin motor for rotating a storage disk in a disk drive according to claim 9, wherein said material is aluminum.
11. The spin motor for rotating a storage disk in a disk drive according to claim 9, wherein the external circumferential surface of the disk support portion has a machined finish.
12. The spin motor for rotating a storage disk in a disk drive according to claim 1, wherein the external circumferential surface of the disk support portion is formed without removal of material.
13. The spin motor for rotating a storage disk in a disk drive according to claim 1, wherein the external circumferential surface of the disk support portion is extruded or cast.
14. The spin motor for rotating a storage disk in a disk drive according to claim 13, wherein said hub is pressed hot onto said magnetic yoke.
15. The spin motor for rotating a storage disk in a disk drive according to claim 1, further comprising:a control member mounted beneath said flange at the axial extremity of the rotor; and a sensor mounted on a printed circuit board on said support member for sensing the passage of said control member to provide a rotation control signal. 16. A spin motor for rotating a storage disk in a disk drive according to claim 15, wherein said printed circuit board is received within a recess in said support member flange.
This application is a continuation of application Ser. No. 08/227,645 filed Apr. 14, 1994 (U.S. Pat. No. 5,422,769, Jun. 6, 1995), which is a continuation of application Ser. No. 08/047,308 filed Apr. 19, 1993 (U.S. Pat. No. 5,446,610, Aug. 29, 1995), which is a continuation of application Ser. No. 07/883,478 filed May 15, 1992 (U.S. Pat. No. 5,216,557, Jun. 1, 1993), which is a continuation of application Ser. No. 07/682,495 filed Apr. 9, 1991 (U.S. Pat. No. 5,128,819, Jul. 7, 1992), which is a continuation of application Ser. No. 07/259,132 filed Oct. 18, 1988 (U.S. Pat. No. 5,006,943, Apr. 9, 1991), which is a continuation of application Ser. No. 07/032,954 filed Mar. 31, 1987 (U.S. Pat. No. 4,779,165, Oct. 18, 1988, now U.S. Pat. No. RE 34,412, Oct. 19, 1993), which is a continuation of application Ser. No. 06/733,231 filed May 10, 1985, abandoned, which is a continuation-in-part of application Ser. No. 06/412,093 filed Aug. 27, 1982, abandoned.
According to the invention, this problem is solved in that at least the part of the rotor casing receiving the storage disk is made from a non-ferromagnetic material and carries the shaft directly or by means of a hub and in that a magnetic shield made from a ferromagnetic material in the form of a drawn can projects into the storage disk receiving part of the rotor casing and is connected thereto. The shielding surrounds the periphery of the magnetically active parts of the driving motor and also envelops the parts at one end. The shield has a central opening whose edge is directly radially adjacent the shaft or parts of the driving motor carrying or supporting the shaft. A rotor casing constructed in this way can be easily manufactured, and it effectively protects the magnetically sensitive storage disks, particularly magnetic hard storage disks, against magnetic stray flux emanating from the magnetically active parts of the driving motor. The shield is preferably in the form of a deep-drawn can, and the part of the rotor casing receiving the storage disk can be made for a lightweight metal by die casting.
Other features of the claimed invention provide a robust precision mounting support for utilizing the available axial overall length for maximizing the distance between the bearings; and permit particularly large distances between the bearings where the axial installation area between a mounting or assembly flange and the end of the storage disk receiving part is limited. Installation space is available on the other side of this flange. Still other features provides for alternative solutions leading to particularly small radial runouts of the rotor; ensure a space-saving housing of the circuit board; and for solutions where importance is attached to a particularly shallow construction.
BRIEF DESCRIPTION OF THE DRAWINGS. The invention is described in greater detail hereinafter relative to non-limitative embodiments and the attached drawings, wherein:
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS. The disk storage drive illustrated in FIG. 1, having an extremely shallow construction, has a brushless direct current motor 45 having a rotor casing 47 fixed to and coaxial with a rotor shaft 46. A stator lamination 48, carrying a stator winding 49, is mounted on a bearing tube 50. The rotor shaft 46 is rotatably mounted within the bearing tube 50 by means of two bearings 52 and 53. These are kept axially spaced by a pair of retaining rings 54. A cup spring 55 is supported on the underside of the bearing 53 by a retaining ring 56 resting on the rotary shaft 46, so that the bearings 52, 53 are axially braced relative to one another. The bearings 52, 53 are pressed into the bearing tube 50 at the time of assembly. Together with an assembly flange 24, the bearing tube 50 forms a one-piece die casting.
The rotor casing 47 comprises a storage disk receiving part 25 and a shielding can 26, which are joined together, for example, by riveting. The storage disk receiving part 25 commonly known as a hub, is made from a non-ferromagnetic material, preferably lightweight metal. The rotor shaft 46 is pressed into a central opening of the storage disk receiving part 25. As an alternative, the shaft can be cast into the receiving part.
The shielding can 26 is made from a ferromagnetic material and can in particular be constructed as a soft iron deep-drawn part commonly known as a soft magnetic annular yoke. A plurality of permanent magnetic segments or a one-part permanent magnet 69 are fixed to the inner face of shielding can 26 radially facing the stator lamination 48 and define the diameter of the substantially cylindrical air gap with respect to the stator lamination 48. The permanent magnet 69 preferably comprises a mixture of hard ferrite, for example, barium ferrite, and an elastic material. Thus, it is a so-called rubber magnet. The latter is trapezoidally or approximately trapezoidally radially magnetized via the pole pitch in a motor construction having a relatively small pole clearance. At the same time, the shielding can 26 forms the magnetic return path for magnet 69. The shielding can 26 surrounds the magnetically active parts 48, 49, 69 of the driving motor 45 on the periphery thereof, as well as on one end thereof. The bottom 28 of shielding can 26 is adapted to the shape of the coil winding heads 27 of the stator winding 49 and contains a central opening 29, whose edge is in the immediate radial vicinity of the circumferential surface of the bearing tube 50 and has a diameter less than the diameter of bearing web 80. In this way, the shielding can effectively prevents the magnetic flux from straying towards the outside of the storage disk receiving part 25.
The storage disk receiving part 25 has two stepped stages 74 and 75, each of whose circumferential surfaces in the present embodiment carry a plurality of radially distributed and projecting bearing webs 79 or 80. The outsides of bearing webs 79, 80 the disk bearing surfaces, are ground in a dimensionally true manner to accommodate the internal diameter of the hard storage disks to be placed on the receiving part 25. The smaller of these opening diameters, for bearing web 80, is less than the air gap diameter. The stepped stages 74, 75 form shoulders 81, 82 and are provided respectively with an annular recess 83 and 84 at the foot axially of bearing webs 79, 80. This structure ensures that storage disks mounted on the bearings webs 79, 80, and having either one of two opening diameters, will cleanly engage against either the shoulder 81 or 82.
Disk storages are most usually operated in "clean room" 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 annular slot 88 is formed in part by an outer portion of assembly flange 24 and has inner and outer diameters accommodating the edge of shielding can 26 and its respective inner and outer diameters. The labyrinth seals 90, 91 are preferably dimensioned in the manner described in the aforementioned U.S. Pat. No. 4,438,542.
The bearing tube 50 projects in the axial direction on the side of the assembly flange 100 remote from the stator lamination 48. As a result, a particularly large axial spacing between the two bearings 52, 53 can be achieved. Axially, bearing 52 is in the vicinity of the axial center of the permanent magnet 69 and of the stator lamination 48. The axial spacing between bearings 52 and 53 is equal to or larger than double the bearing external diameter. To prevent electrical charging of the rotor which in operation rotates at high speed and which would disturb the operational reliability of the disk storage device, the rotor shaft 46 is electrically conductively connected to the equipment chassis by means of a bearing ball 78 and a spring contact (not shown). The printed circuit board 101, carrying the rotary position detector 63 and the other electronic components, is supported on the and of a spacer ring 102 facing an assembly flange 100 and is located between the flange and the stator lamination 48. An annular slot 103 is formed in assembly flange 100 and is aligned with the annular circuit board 101. The annular slot 103 provides space for receiving the wire ends and soldered connections projecting from the underside of the circuit board 101.
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 described hereinbefore.
In a further development of the invention where a disk storage drive utilizes a brushless D.C. drive motor having a stator provided with a winding and an external rotor coaxially surrounding the stator and spaced therefrom by a substantially cylindrical air gap, the rotor including a permanent magnetic rotor magnet and a soft magnetic yoke. The motor further includes a hub concentric to the yoke and connected to the rotor for rotation therewith. The hub is a disk mounting or support portion, which extends through the central opening of the storage disk and receives at least one storage disk in a clean area space, or chamber of a storage drive.
At least those surface parts of the hub located in the clean area or chamber of the drive must not give off, even during prolonged use of the disk storage drive, significant quantity of dirt particles, for example, from oxidation. Preferably, the hub is made from a material which, even after cutting, is suitable for use in a clean area or chamber, that is, a material which after being cut, and without a corrosion-inhibiting treatment following the cutting, meets the strict cleanness conditions necessary with disk storage drives in the clean chamber of the drives receiving the storage disks. Such a construction makes it possible to finish, for example, by grinding or otherwise stripping the outer peripheral surface of the disk support portion after assembly of the hub and the drive motor with respect to the centricity with the rotation axis. Such metal finishing of the installed hub is frequently necessary in order to fulfil the extreme demands in connection with disk storage drives with respect to accuracy of rotation or minimization of untrueness of the hub. It is particularly appropriate to have a hub made from light metal, preferably aluminum or an aluminum alloy. Light metal hubs can be used in clean chambers without further treatment, even after cutting has taken place. For example, by using a diamond tool, and while respecting the necessary precision, such hubs can be stripped in a less expensive way than by grinding, particularly the disk mounting portion with a cylindrical outer circumferential surface. The hub is preferably impact extruded or cast and is pressed hot on to the magnetic yoke. In principle, other possibilities for joining hub and yoke exist, such as a bonding together of the two parts.
In FIGS. 5 and 6, the drive motor 118 has a stator 119 with a stator lamination bundle 110. The bundle 110 is radially symmetrical with respect to a central rotation axis 110A and is provided with an annular central portion 110B. The stator laminations 110 form six stator poles 111A to 111F, each of which, in the plan view according to FIG. 5 has a substantially T-shaped configuration. The stator poles are positioned with a reciprocal angular distance of 60�. A sintered iron core can be provided in place of a bundle of laminations. Pole shoes 112A to 112F of the stator poles together with a permanent magnetic motor magnet 113 define a substantially cylindrical air gap 114. In the manner indicated in FIG. 5, motor magnet 113 is radially magnetized in quadripolar manner in the circumferential direction, that is, it has four portions 113A to 113D and on the inside of the annular motor magnet 113 facing the air gap 114 are provided in alternating sequence two magnetic north poles and two magnetic south poles 115, 116. In the illustrated embodiment, each of the poles 115 and 116 have a width of substantially 180� e1, (corresponding to 90� mechanical). Thus, an approximately rectangular or trapezoidal magnetization is obtained in the circumferential direction of the air gap 114.
The motor magnet 113 is fitted in a soft magnetic material external rotor cup or pot 117 serving as a magnetic yoke and has a magnetic shield bonded thereinto. The cup 117 and the magnet 113 together form an external rotor 130. The external rotor cup 117 has an end wall 117A (FIG. 6) and a cylindrical circumferential wall 117B. The motor magnet 113 can be a rubber magnet, or a plastic-bonded magnet. In place of a one-part magnet ring, dish-shaped magnet segments can be bonded or in some other way fixed into the cup 117. Particularly suitable materials for the magnet ring or segments are magnetic material in a synthetic binder, a mixture of hard ferrite and elastomeric material, ceramic magnetic material or samarium cobalt.
While in the represented embodiment each of the poles extends over substantially 180� e1, it is also possible to work with narrower poles. The rotor pole width, however, should be at least 120� e1 to obtain a high motor output.
Together the stator poles 111A to 111F define six stator slots 120A to 120F, in which is placed a three-strand stator winding. Each of the three strands includes two 120� e1-cored coils 121,122; 123,124; and 125,126. Each is wound around one of the stator poles 111A to 111F. The two coils in series of each strand diametrically face one another, as shown in FIG. 5. The coils are preferably wound in bifilar manner (not shown). As can be gathered from the diagrammatic representation of FIG. 5, any overlap between coils 121 to 126 is avoided and in this way particularly short coil winding heads 127 (FIG. 6) are obtained. The slot openings 128A to 128F can be between 3� e1 and 30� e1. In the present stator winding configuration, slots 120A to 120F can be excellently filled. There is generally no need to provide caps for the slot openings 128A to 128F.
A preferably light metal hub 137 (FIG. 6) for a rigid disk is provided with a cylindrical disk mounting portion 136 and is placed, for example, by shrinking onto the external rotor cup 117. One or more rigid storage disks 139, preferably magnetic disks, are placed on the disk mounting portion 136. The disk mounting portion extends through a central opening 140 in the storage disks 139, which are reciprocally axially spaced by spacers 141 and are fixed with respect to the hub 137 by a known clamping device. In the embodiment shown in FIG. 6, somewhat more than 2/3 of the axial dimension of the magnetically active stator and rotor parts of drive motor 118, that is, the motor magnet 113 and the stator windings 121 to 126 project into a space or volume 146 surrounded by the disk mounting portion 136. The wall thickness of the disk mounting portion 136 of the hub 137 is smaller than the wall thickness of the cylindrical circumferential wall 117B of the cup 111 that forms the magnetic yoke, so that a maximum cross section is made available for the rotor parts 113, 117, 119 in the predetermined central opening 140. In particular, the wall thickness of the disk support portion 136 is made as small as possible consistent with mechanical strength requirements. To increase the dimensional stability of the hub 137, near the open end of the unit that includes the hub 137, the external rotor cup 117 and the motor magnet 113, the hub carries a thickened, outwardly radially projecting flange 147, which simultaneously axially supports the rigid storage disk 139 closest to the flange.
The assembly flange 135 carries a circuit board 138, which can optionally carry the commutating electronics and/or other circuit components, such as for speed regulation. The circuit board 130 more particularly carries three rotation position sensors 142, 143, 144. In the illustrated embodiment, they are magentic field sensors, such as Hall generators, field plates, magnetic diodes and the like. Bistable-switching Hall IC's are particularly advantageous. The use of 180� e1 wide rotor poles 115, 116 makes it possible to use the motor magnet 113 as the control magnet for the position sensors 142, 143, 144. The embodiment according to FIG. 6 shows the rotation position sensors 142, 143, 144 (of which only sensor 142 is seen) axially facing the magnet 113 controlling them. It is also possible to arrange the rotation position sensors in the manner indicated in broken line form in FIG. 6 to radially face the magnet 113 controlling them. The rotation position sensors 142, 143, 144 are appropriately so peripherally positioned with respect to the coils 121 to 126 that changes to the sensor switching states substantially coincide with the zero crossings of the associated coil voltages. In the embodiment according to FIG. 5 this is achieved in that the rotation position sensors are displaced by 15� mechanical with respect to the center of the slot openings 128A, 128B, 128C.
FIG. 8 illustrates another embodiment of the disk storage drive in which, differing from the embodiment of FIG. 6 and 7, a hub 164 corresponding to the hub 137 has an end wall 164A engaging the end wall 117B of the external rotor cup 117. A bearing bush 165 for the shaft 132 is formed integrally in the end wall 164A. On the end of the disk support portion 166 of the hub 164 remote from the end wall 164A is located a radially outwardly bent flange 167, which passes into a circumferential wall 168 concentric to, but having a larger diameter than the disk mounting portion 166. Radially outwardly bent flange 167 and circumferential wall 168 together comprise a disk support shoulder that is disposed substantially completely within a recess 189 of assembly flange 183. A sidewall 192 of recess 189 parallels circumferential wall 168. Assembly flange 183 has a flat portion 193 that extends radially outside of the recess 189. The circumferential wall 168 engages radially and externally over the flange 117C of the cup 117. The junction between the flange 117C and the circumferential wall 168 is sealed in the manner indicated at 169 by varnish, adhesive or the like. Thus, as in FIG. 7, it is ensured that dirt particles are not passed radially outwardly from the flange 117C and from the recess 189 of assembly flange 183 into the clean chamber 149. The control magnet 145 interacting with the rotation position sensors (of which only sensor 142 is shown in FIG. 8) is axially aligned with the motor magnet 113 and is fitted to the side of the magnet 113 remote from the end wall 117A. The external rotor cup 117 is drawn down into the recess 189 of flange 183 to such an extent in FIG. 8 that it surrounds the control magnet 145. The space left free between the end wall 117A and the end of the magnet 113 facing the wall is filled with an adhesive or some other filling material 170. The bearing system for the shaft 132 formed by the two ball bearings 133 is sealed with respect to the inner area of the motor and consequently with respect to the clean chamber 149 by means of a magnetic fluid seal 172, which comprises two annular pole pieces 173, 174, a permanent magnet ring 175 located between these pole pieces and a magnetic fluid (not shown), which fluid is introduced into an annular clearance 176 between the magnet ring 175 and a portion 177 of the shaft 132. Seals of this type are known as "ferro-fluidic seals". The seal 172 effectively prevents the passage of dust particles from the bearing system into the clean chamber 149. The seal 172 is adjacent to, but axially spaced from, the bearing bush 165, which ensures that magnetic fluid is not drawn by capillary action out of the seal 172.
The circuit board 138 is connected to the assembly flange 183 in the recess 189 via an adhesive coating 184, which is located in a slot 185 in the recess 189 of the assembly flange 183. To further reduce the overall axial height of the disk storage drives, the circuit board 138 is provided with openings 186 in the vicinity of the rotation position sensors, and the rotation position sensors are introduced into the slot 185 and the openings 186. Near the engagement point between the upper pole piece 173 and the inner circumferential wall 187 of the sleeve 182, an additional seal by means of coating lacquer or the like is provided at 188.
FIG. 10 shows a further modified embodiment of the invention, which essentially differs from the previous constructions of FIGS. 5-9 in that the external rotor cup 117 is replaced by a soft magnetic yoke ring 194 and a separate soft magnetic shield ring 195. The shield ring 195 extends from the clean chamber-side axial end 196 of the yoke ring 194 in a radially inwardly direction. The wall thickness of the shield ring 195 can be much less than that of the yoke ring 194. Threaded holes 197 functionally corresponding to the threaded holes 190 of FIG. 9 are formed in the end wall 198 of a hub 199, in which integrally is formed the beating bush 1100 for the shaft 132. Near the threaded holes 197, a shield ring 195 is provided with depressions 1101, which depressions permit the use of the full thread length of the threaded holes 197. Filling material 170 is provided in the space between the upper end of the motor magnet 113 in FIG. 10, the end 196 of the yoke 194 and the radially outer part of the shield ring 195. The magnetically active rotor and stator parts are more than 2/3 located in the area surrounded by the cylindrical disk support portion 1102 of the hub 199.
The yoke ring 194 can be a rolled ring, particularly a steel ring, or a portion of a tube. Manufacture is simplified compared with the use of an external rotor cup 117. In addition, additional axial length is saved, because on the one hand the wall thickness of the shield ring 195 can be kept small, and because on the other hand no space is lost, considering the way in which some space is required when using the cup 117 with its radius r (FIG. 9) at the transition point between its circumferential wall 117B and its end wall 117A. The axial construction space which thus has been made available can be used to give the and wall 198 a greater thickness and consequently increase the length of the threaded holes 197.
Whereas in the case of the embodiment according to FIGS. 5 to 10, the shaft 132 rotates in operation, FIGS. 11 and 12 illustrate embodiments with a stationary shaft 1105. According to FIG. 11, the shaft 1105 is fitted into the disk storage device. By means of the first ball bearing 1106, a hub 1107 is mounted on shaft 1105 to rotate therewith. The hub 1107 has an end wall 1108 with a formed-in bearing bush 1109, a disk support portion 1110 and, on the side remote from end wall 1108, a radially outwardly projecting reinforcing flange 1111. The hub 1107 is connected to a soft magnetic yoke ring 194. The soft magnetic shield ring 195 engages the inside of the end wall 1108. The circuit board 138 with the rotation position sensors, of which only the sensor 142 is shown in FIG. 11, is suspended by means of supports 1112 (FIG. 12) on the stator laminations 110. motor cover 1114 is mounted by means of a second ball bearing 1113 on the shaft 1105, the cover tightly sealing the motor on the axial end remote from the end wall 1108. A magnetic fluid or ferrofluidic seal 172 or 172' discussed in detail relative to FIG. 8, is provided on each of the outside of the bearings 1106, 1113. The seals 172, 172' ensure a sealing of the bearing system with respect to the clean chamber 149, so that the complete drive motor can be located in the clean chamber. The connections of the stator winding and/or the electronic components mounted on the circuit board 138 can be led out by means of a cable 1115, which is placed in an axial slot 1116 of the shaft 1105.
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KgDisk storage device with improved spindle torque and accelerationUS6344946Oct 26, 1999Feb 5, 2002Papst Licensing GmbhDisk storage device with improved spindle torque and accelerationUS6384503 *Apr 18, 2000May 7, 2002Seiko Instruments Inc.MotorUS6411463Jul 20, 2000Jun 25, 2002Seagate Technology LlcInsert for dampening acoustic vibration and shielding magnetic flux for use in a disc driveUS6741007 *Jul 27, 2001May 25, 2004Beacon Power CorporationPermanent magnet motor assembly having a device and method of reducing parasitic lossesUS6911749 *Jun 17, 2004Jun 28, 2005Lite-On It Corp.Spindle motor structureUS7659648 *Mar 10, 2004Feb 9, 2010Comair Rotron Inc.Motor with raised rotorUS7692892 *Jul 19, 2006Apr 6, 2010Seagate Technology LlcTwo-material base for a data storage systemUS7847452Jan 11, 2010Dec 7, 2010Brown Fred AMotor with raised rotor* Cited by examinerClassifications U.S. Classification360/98.07, G9B/19.028, G9B/17.012, 360/99.08, G9B/19.027, G9B/25.003International ClassificationG11B25/04, G11B17/038, H02K5/22, H02K7/08, H02K11/00, H02K3/28, H02P6/08, H02K5/167, H02K21/22, H02K29/08, H02K7/14, G11B19/20, H02K5/173, H02K5/10, H02K5/124Cooperative ClassificationH02K11/0005, H02K2211/03, H02K5/167, H02K3/28, H02K7/08, H02K7/14, H02K11/0089, H02K5/10, G11B19/2009, H02K21/22, G11B19/20, H02P2209/07, H02K5/124, H02K5/1737, G11B17/038, H02P6/085, G11B25/043, H02K7/086, H02K29/08, H02K5/225, H02K7/085, H02K5/1735European ClassificationH02K11/00J, H02K5/22B, H02K7/08E, H02K7/14, H02K29/08, H02K7/08D, G11B25/04R, H02K5/173D, H02K5/124, G11B19/20, H02P6/08B, G11B19/20A, H02K5/10, H02K21/22, G11B17/038, H02K5/173E, H02K11/00BLegal EventsDateCodeEventDescriptionNov 2, 2009FPAYFee paymentYear of fee payment: 12Oct 4, 2005FPAYFee paymentYear of fee payment: 8May 28, 2002SULPSurcharge for late paymentMay 28, 2002FPAYFee paymentYear of fee payment: 4Jan 22, 2002REMIMaintenance fee reminder mailedMay 14, 1999ASAssignmentOwner name: PAPST LICENSING GMBH & CO. KG, GERMANYFree format text: LEGAL ORGANIZATION CHANGE;ASSIGNOR:PAPST LICENSING GMBH;REEL/FRAME:009922/0250Effective date: 19981103RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services©2012 Google