JPH0782699B2 - Disk drive - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a stator having windings, and an outer rotor having a permanent magnet electric motor magnet that coaxially surrounds the stator by forming a substantially cylindrical air gap, And a non-collecting electric motor having a soft magnetic back cover, and a central hole of the storage disk for accommodating at least one storage disk concentrically coupled to the back cover and non-rotatably provided in the clean room. And a boss having a disc supporting portion that can be inserted into the disc driving device.

[Prior Art] In a known disk drive device of this type (FIGS. 3 and 4 of West German Patent Application Publication No. 3135385), a relatively sturdy member is provided as a boss for accommodating a storage disk. The member comprises a bearing frame extending axially in the area of the disc support, which is non-rotatably coupled to the shaft by a bearing bush which is pressed or cast into the boss and which acts magnetically on the stator part and It covers the rotor part, i.e. the stator windings and a small axial dimension of the motor magnets which cooperate with it, together with the disk support.

[Problems to be Solved] In the case of a disk storage device, there is an increasing demand for reducing the occupied space of the storage device.

Therefore, a basic object of the present invention is to provide a disk drive device which occupies a particularly small space and which minimizes the size of the disk storage device, especially in the axial direction.

The present invention provides a disk drive device having a structure that guarantees strict mechanical precision, in particular, based on the above-mentioned basic object.

SOLUTION: According to the invention, the object of the present invention is to provide a stator winding and a motor magnet which cooperates therewith, the substantial main part of which is surrounded by the disk support of the boss in the axial dimension. The boss is provided inside the space, and the cylindrical portion and / or the flat portion forming the outer peripheral surface of the disc support portion are provided for centering the rotary shaft after assembling the boss with the drive motor. In the case of this construction achieved by being superfinished, the magnetically active part of the drive motor is absolutely necessary for holding storage disks, especially magnetic hard disks or other types of storage disks, for example optical storage disks. It occupies most of the interior of the space.

[Preferable Embodiments and Effects] The stator winding and the electric motor magnet that operates in cooperation with the stator winding are provided in at least 2/3 of the axial dimension inside the space surrounded by the disk supporting portion. Preferably. A particularly space-saving overall construction is obtained if the magnetically acting stator and rotor parts are almost completely in this space.

The diameter of the central hole of a storage disk such as a magnetic hard disk is standardized and its size is limited to a fixed value. On the other hand, the generation of drive energy requires some motor size. For a known small storage disk, for example with a central hole diameter of only 25 mm, this is particularly critical. In order to provide as many places as possible for the magnetically acting motor part in the space of the central hole of the storage disk of limited diameter, the mechanical strength is taken into account in the development of the invention. The wall thickness of the disk support of the boss is made as thin as possible. In that case, the wall thickness of the disk support portion is equal to the wall thickness of the portion of the magnetic circuit member that is concentric with the disk support portion, or
Alternatively, it is preferably smaller than this.

In addition, the disk support is effective because it provides a maximum cross-section given the given diameter of the central hole of the storage disk and the required mechanical strength of the boss for the magnetically acting motor part. Preferably, it comprises a cylindrical outer peripheral surface, ie a peripheral surface without known bearing frames or bearing ribs.

At least the surface portion of the boss in the clean room must not release any dust into the clean room or practically at all, even if the disk drive is used for a long time.
The boss is a material suitable for the clean room even after machining such as cutting and grinding / polishing, that is, in the case of the storage disk in the clean room that accommodates the storage disk without the post-corrosion post-processing after machining. It is preferably made of a material that complies with the strict cleaning conditions required. By constructing the boss in this manner, the outer peripheral surface of the disk support can be superfinished, for example, ground or turned, after the boss is combined with the drive motor to center it with the rotary shaft. This is effective for guaranteeing extremely high mechanical precision required in response to an increase in track density in a magnetic disk storage device, particularly a drive device such as a hard disk. At the time of rotation, the boss surface changes from a logical value of machine accuracy, and the maximum value of the radial change of the boss surface is called TIR (Total Indicated Run-out), for example, about 5
-15 μm, the deviation of the displacement during operation from the average value of the radial displacement of the boss surface during rotation is usually called non-repetitive shake, and the minimum deviation is 0.2-0.5 μm.
It is assumed to be around m (the manufacturer guarantees this value).
Furthermore, the radial accuracy of the cylindrical part of the disk support part of the boss is
The flatness of the surface of the flat portion of the boss is preferably about 1 μm or less. In the case of disk storage, such precision machining of the assembled boss is often necessary to meet the strong demand for minimizing concentric rotation or vibration of the boss. For this reason, the mounting base of the electric motor is fixed to a predetermined reference point, and the disk support of the boss is superfinished in the axial and radial directions. It has been found that bosses made of light metals, especially aluminum or aluminum alloys, are particularly effective. The light metal boss retains its suitability for clean rooms without post-treatment after machining. This makes it possible to carry out turning with the required precision, for example by means of diamond tools, which is more economical than grinding, in particular in the case of disk supports with a cylindrical outer peripheral surface. The boss is preferably extruded or cast and thermocompression bonded to the magnetic circuit member. However, in principle, other possibilities of joining the boss and the magnetic circuit element are also conceivable, for example by adhering these elements together.

The magnetic circuit member can be formed into a cup shape by a method known per se. In particular, an annular magnetic circuit element can be provided, in which case a magnetic shield ring extending radially inward from the clean chamber side axial end of the annular magnetic circuit element is fitted snugly in the boss. In this way, the required induction of magnetic flux and effective magnetic shielding of the storage disk to the drive motor are obtained. The combination of the magnetic circuit ring member and the shield ring can be economically manufactured in the shape of a cup. The shield ring can be made relatively thin, which further reduces the overall axial length of the drive and, if this total length is the same, the closed end of the group of bosses, magnetic circuit members and motor magnets. Many spaces can be used for the end wall of the boss in the section. The magnetic circuit member is a rolling ring, especially a steel ring,
Or it can be reasonably formed as a tube section.

The rotor and the boss can be at least partially fixedly connected to a shaft mounted on a bearing arrangement provided in the stator of the drive motor. In that case, the bearing bush containing the shaft can be formed integrally with the magnetic circuit member if it is formed in the shape of a cup, or in particular with the boss. Therefore, no special components for the bush are needed. However, the rotor and the boss can also be rotatably supported on the fixed shaft by means of a bearing arrangement by means of a modified development, in which case the conductors of the stator windings pass through the fixed shaft to the outside of the drive. Is taken out.

A commutation signal and possibly an additional control signal, for example in the form of a control magnet ring, which cooperates with a static magnetic field sensitive rotary position sensor device intended to generate a signal for a predetermined reference position of the rotor. Control magnets are reasonably combined with the rotor and boss unit. In that case, the control magnet is preferably provided on the axially open side of the unit including the rotor and the boss. The control magnet can be axially aligned with the motor magnet. In some cases, the motor magnet itself can also be used as the control magnet. The rotational position sensor device is preferably attached to a printed circuit board that axially faces the axially open side of the unit including the rotor and the boss.

It should be noted that the reference signs attached to the embodiments in the claims are for facilitating understanding and are not necessarily limited to the illustrated ones.

[Examples] Next, the present invention will be described in more detail by way of preferred examples.

In FIGS. 1 and 2, a drive motor, generally designated by reference numeral 18, comprises a stator 19 having a stator laminate 10. The stator laminated plate 10 is radially symmetrical with respect to the central rotation axis 10A, and includes a ring-shaped central portion 10B. The stator laminate 10 forms six stator poles 11A to 11F, which are substantially T-shaped in the plan view shown in FIG. 1 and are arranged at 60 ° angular intervals from each other. Has been. For example, a sintered iron core can be used instead of the laminated plate. The pole pieces 12A to 12F of the stator poles, together with the permanent magnet motor magnet 13, form a substantially cylindrical air gap 14. Motor magnet 13
Is magnetized in the radial direction with four poles in the circumferential direction, that is, the motor magnet 13 is provided with four parts 13A to 13D in the direction of the air gap 14 of the annular motor magnet 13 as shown in FIG. On the inside facing, there are alternately two magnetic north poles and two magnetic south poles 15 and 16. The poles 15, 16 have a width of approximately 180 electrical degrees (mechanically equivalent to 90 °) in the illustrated embodiment. In this way, approximately rectangular or trapezoidal magnetization is obtained in the circumferential direction of the void 14.

The electric motor magnet 13 is mounted in an outer rotor cup 17 made of a soft magnetic material that functions as a magnetic circuit member and as a magnetic shield, and is adhered to the outer rotor cup, for example. Cup 17 and magnet 13 are outer rotor
Make up thirty. The outer rotor cup 17 has an end face wall portion 17A and a cylindrical peripheral wall portion 17B. In the case of the electric motor magnet 13, this can in particular be a rubber magnet or a synthetic resin bonded magnet. Instead of an integral magnet ring,
The shell-shaped magnet segment can be glued or otherwise secured thereto. Particularly suitable materials for the magnet ring or magnet segment are magnetic materials in synthetic binders, mixtures of hard ferrites and elastomeric materials, porcelain magnet materials or samarium cobalt. In the illustrated embodiment, each pole is effectively extended to an electrical angle of 180 °, but it is also possible to work with smaller poles. However, in order to obtain a high motor output, the width of the rotor pole must be at least 120 electrical degrees.

The stator poles 11A to 11F divide the six stator grooves 20A to 20F as a whole. A three-phase stator winding is fitted in this groove. In that case, each of the three-phase windings has two coils 21, 22; 23, 24 and 25, which are offset by an electrical angle of 120 °,
26, each of which is wound on one stator pole 11A-11F. As shown in FIG. 1, two coils connected in series in each phase winding are provided on opposite sides in the diametrical direction. Although not shown, these coils are wound in particular in two turns. As can be seen from the schematic diagram in FIG. 1, the respective overlap between the coils 21 to 26 is avoided. In this way, a particularly short coil head 27 (FIG. 2) is obtained. Groove openings 28A to 28F
Can range in electrical angle from 3 ° to 30 °. The formation of the stator windings causes the grooves 20A to 20F to be considerably filled. Generally, a lid for groove openings 28A-28F is not required.

The structure of the electric motor shown here is the stator groove 20A to 20F.
Since the depth of can be made relatively small, a relatively large stator inner hole 29 can be obtained. The ratio of the diameter I of the inner hole 29 to the outer diameter E of the stator of the pole piece 12 must be at least 0.35.
Is obtained. The I / E value is preferably in the range of 0.4 to 0.7. The ratio of the axial length L of the stator core to the stator outer diameter E is preferably equal to or less than 1. This dimensional ratio is particularly important for stable support of the rotor. Such support is especially important when driving a disk storage device. Moreover, the overall resistance of the stator winding is particularly low.

In order to support the rotor 30, as shown in FIG. 2, at the center of the outer rotor cup 17, a short shaft 32 is fixed via a bearing bush 31 formed on the outer rotor cup 17,
This short shaft is a ball bearing that is axially provided at a distance from each other.
The stator laminated plate 10 is supported via 33 and the assembly flange 35
It is held in a cylindrical bushing 34 fixed to the.

The outer rotor cup 17 is provided with a cylindrical disk support 36 (not shown in FIG. 1) and is fitted with a boss 37 of a fixed disk storage device made of light metal, for example, and is fixed by shrink fit. . The disk support 36 has
One or several fixed storage disks 39, in particular magnetic fixed storage disks, are fitted, in which case the disk support
36 is passed through the central hole 40 of the storage disk 39,
The 39 are axially spaced from each other by suitable spacers 41 and are fixed to the boss 37 by fastening means known per se, not shown. In the embodiment shown in FIG. 2, the magnetically acting stator and rotor parts of the drive motor 18, that is to say the motor magnets 13 and the stator windings 21 to 26, are approximately 2 / of their axial dimension. Three or more enter into the space 46 surrounded by the disk support 36. The wall thickness of the disk support portion 36 of the boss 37 is smaller than the cylindrical peripheral wall 17B forming the magnetic circuit member of the outer rotor cup 17, and thus the motor portion 13, 17, in the well-defined central hole 40, The largest cross section for 19 is prepared. In particular, the wall thickness of the disk support portion 36 is made as small as possible in terms of mechanical strength. In order to increase the dimensional stability of the boss 37, this boss axially moves a fixed storage disk 39 adjacent to the flange 47 at the open end of the element consisting of the boss 37, the outer rotor cup 17 and the motor magnet 13. Acts to support. It supports a thick flange 47 protruding outward in the radial direction.

The boss 37, with the storage disk 39 supported on it,
Although not shown in detail, it is inside a clean room 49 defined by the housing part of the disk storage device in a manner known per se. In that case, the assembly flange 35
Form part of the boundary of the clean room to the bottom of FIG. The upper bearing 33 in FIG.
Between the shoulder portion 51 and the spacer ring 52, and the side of the ring 52 opposite to the bearing 33 is in contact with the lower side of the bearing bush 31. The lower end of the short shaft 32 is formed in a spherical shape, and is suitably supported by a thrust bearing (not shown). A retaining ring 55 is provided in an annular groove 54 of the shaft 32 near the lower end 53, on the upper side of which two spring washers 56 rest. The spring washer 56 is in contact with the intermediate ring 57. Lower ball bearing 33
Is between the intermediate ring 57 and another shoulder 58 of the bushing 34.

The assembly flange 35 comprises a printed circuit board 38, which can optionally be provided with commutation electronics and / or other circuit elements, for example for speed regulation. The printed circuit board 38 is provided in particular with three rotational position sensors 42, 43, 44, which are magnetic field sensors, for example Hall generators, magnetoresistive plates, magnetic diodes, etc. in the illustrated embodiment. A bistable connection hole integrated circuit is particularly preferable. By using the rotor poles 15 and 16 with an electrical angle of 180 °, as control magnets for the position sensors 42, 43 and 44,
The motor magnet 13 can be used directly. In the case of the embodiment shown in FIG. 2, the rotational position sensors 42, 43, 44
Are axially opposed to the magnet 13 that controls them. However, for example, a rotational position sensor may be controlled by a magnet that controls it, as indicated by the dashed line in FIG.
It may be provided so as to face 13 in the radial direction. The rotary position sensors 42, 43, 44 are provided in the correct position in the circumferential direction with respect to the coils 21 to 26, so that the change in the connection state of the sensors takes place at approximately the same time as the zero crossing point of the corresponding coil voltage. This is the case in the embodiment shown in FIG.
This is accomplished by offsetting the rotational position sensor by a mechanical angle of 15 ° with respect to the center of the groove openings 28A, 28B and 28C.

The embodiment shown in FIG. 3 differs from the embodiment shown in FIG. 2 in that a control magnet 45 different from the motor magnet 13 for controlling the rotational position sensors 42, 43, 44 is provided. There is. The control magnet 45 is provided outside the radial direction of the motor magnet 13 at the opening end of the outer rotor cup 17 and below the flange 17C that projects radially outward from the peripheral wall 17B thereof. Outer rotor cup 17 and boss
37 'are just terminated to each other at the open end in the embodiment shown in FIG. The terminals of one of the coils 21, 26 at the connection point of the printed circuit board 38 are indicated schematically by the reference numeral 59. A connection cable 60 is drawn out from the printed circuit board 38 through the through hole 61 of the assembly flange 35.

FIG. 4 shows another embodiment of the disk drive device, in which the boss 64 functionally corresponding to the boss 37 is different from the outer rotor cup, unlike the structure shown in FIGS. 2 and 3. Bearing bush 65 of shaft 32 adjacent to end wall 17A of 17
Is provided integrally with the end face wall 64A. Boss 64
At the end far away from the end surface 64A of the disc support portion 66, there is a flange 67 that is bent outward in the radial direction, and this flange 67 is located concentrically with the disc support portion 66 and is compared to the disc support portion 66. To a peripheral wall 68 having a large diameter. The peripheral wall 68 surrounds the flange 17C of the outer rotor cup 17 on the outer side in the radial direction. Flange 17C and peripheral wall
The joint with 68 is sealed with varnish, adhesive, etc., as indicated by reference numeral 69. By doing so, as in the case of FIG. 3, dust is prevented from being radially emitted from the flange 17C to the outside and entering the clean room. A control magnet 45, which cooperates with the rotational position sensor (of which only sensor 42 is shown in FIG. 4), is axially aligned with the motor magnet 13 and
Is provided on the side far away from the end surface 17A. The outer rotor cup 17 extends downward in FIG. 4 to the extent that it also surrounds the control magnet 45. The space between the end wall 17A and the end of the magnet 13 facing this end wall is filled with an adhesive or other filling material. The bearing device for the shaft 32, which is composed of two ball bearings 33, is sealed to the internal space of the electric motor and the clean room by a magnetic fluid seal. The magnetic fluid seal 72 includes two annular pole pieces 73, 74.
And a permanent magnet ring 75 between these two pole pieces
And a magnetic fluid (not shown) contained between the magnet ring 75 and a portion 77 of the shaft 32. This type of seal is known by the trade name "Ferrofluidic seal". The seal 72 particularly effectively prevents dust from being discharged from the bearing device into the clean chamber 49. The seal 72 is provided adjacent to the bearing bush 65 but at a distance in the axial direction. By doing so, the magnetic fluid is prevented from being pulled out of the seal 72 by the capillary action.

As can be seen from FIG. 4, the magnetically actuated stator and rotor parts are almost completely provided inside the space 46 surrounded by the disk support 66. Further, FIG. 4 shows the thrust bearing of the shaft 32. This bearing 79
The bushing 82 is provided on a curved spring 80 attached to a lid 81 at an end far from the clean room 49. Bushing 82
Is the bushing 34 of the embodiment shown in FIGS. 2 and 3.
Similarly, the bearing 33 is accommodated, but is integrally connected to an assembly flange 83 corresponding to the assembly flange 35.

The thrust bearing 79 is preferably electrically conductive like a curved spring. By doing so, electrostatic charging of the shaft 32 can be discharged through the bearing 79 and the bending spring 80. The printed circuit board 38 is joined to the assembly flange 83 by a layer of adhesive 84 in a groove 85 in the assembly flange 83. In order to further reduce the axial height of the disk drive device, the printed circuit board 38 is provided with a through hole 86 in the range of the rotational position sensor, and the rotational position sensor includes the groove 85 and the through hole.
It is in 86. Upper pole piece 73 and bushing
An additional packing, such as a coating varnish, designated by the reference numeral 88, is provided at a portion of the contact portion 82 between the inner peripheral wall 87 and the inner peripheral wall 87.

The embodiment shown in FIG. 5 is remarkably similar to the embodiment shown in FIG. In this case, the bearing bush 31 is different in that it is integrally formed with the end surface wall 17A of the outer rotor cup 17 that acts as a magnetic shield. The end wall 17A is provided with three screw holes 90 which are offset from each other by 120 ° in the circumferential direction. The screw hole 90 is used for the fixed storage disk 39 (secondary disk).
It is used for mounting a fixing device (not shown). Under the end wall 17A, a cover ring 91 for sealing the internal space of the electric motor with respect to the clean room 49 at the screw hole 90 portion.
There is. Also in this case, as in the case of FIG. 3, the stator portion of the drive motor magnetically acting over most of the axial length in the space 46 surrounded by the disk support portion 36 'of the boss 37' and There is a rotor part.

FIG. 6 shows another modified embodiment of the present invention, in which the outer rotor cup 17 is replaced by a low remanence magnetic circuit ring member 94 and another, similarly low, magnetic circuit ring member 94. It is basically different from the above-described structure in that it has a remanent shield ring 95. The shield ring 95 is a magnetic circuit ring member.
94 extends inward in the radial direction from the axial direction draft portion on the clean room side. The wall thickness of the shield ring 95 depends on the magnetic circuit ring member 94.
It can be much thinner than the wall thickness. A screw hole 97 functionally corresponding to the screw hole 90 of FIG. 5 is provided in an end wall 98 of a boss 99 integrally formed with the bearing bush 100 of the shaft 32. The shield ring 95 has a recess 101 at the portion of the screw hole 97 that allows the entire screw length of the screw hole 97 to be formed.
Is equipped with. The filler 70 is a motor magnet in FIG.
The region between the upper end of 13, the end 96 of the magnetic circuit ring member 94, and the radially outer portion of the shield ring 95 is filled. The magnetically acting rotor portion and stator portion occupy 2/3 or more of the space surrounded by the cylindrical disk support portion 102 of the boss 99.

In the case of the magnetic circuit ring member 94, this can be a rolling ring, in particular a steel ring or a tube section. This manufacture is simplified compared to the use of the outer rotor cup 17. On the other hand, since the wall thickness of the shield ring 95 can be reduced on the one hand, when the outer rotor cup 17 is used on the other hand, the unavoidable radius γ at the transition point between the peripheral wall 17B and the end face wall 17A ( The additional axial length is saved because there is no space required (Fig. 5). The available axial space can also be used to make the end wall 98 thicker and thus to increase the length of the threaded hole 97.

In the case of the embodiment shown in FIGS. 1 to 6, the shaft 32 rotates during operation, while FIGS. 7 and 8 show an embodiment with a fixed shaft. Although not shown in detail, the fixed shaft 105 shown in FIG. 7 is attached to a disk storage device. A boss 107 is rotatably supported on the shaft 105 by a first ball bearing 106. The boss 107 includes an end face wall 108 having an integrally formed bearing bush 109, a disk support portion 110, and a reinforcing flange 111 protruding outward in the radial direction on the side far from the end face wall 108. ing. The boss 107 is connected to the magnetic circuit ring member 94 having a low remanence. A shield ring 95 having a low remanence is in contact with the inside of the end wall 108. The printed circuit board 38 with the rotational position sensor, in which only the sensor 42 is shown in FIG. 7, is in this case mounted on the stator laminate 10 by means of the columns 112 (FIG. 8).
Are suspended by. The fixed shaft 105 has an electric motor lid that seals the electric motor at an axial end far from the end wall 108.
114 is supported by the second ball bearing 113. Bearing 10
On the outside of 6, 113, magnetic fluid seals 72, 72 'of the type described in detail with reference to FIG. 4 are arranged to seal the bearing device against the clean chamber 49, in which case the entire drive motor. Can be placed in a clean room. The fixed windings and / or the terminals of the electronic components mounted on the printed circuit board 38 can be led out by a cable indicated by the reference numeral 115, which is housed in the axial groove 116 of the shaft 105.

The embodiment shown in FIG. 8 is basically different from the embodiment shown in FIG. 7 in that the magnetic circuit ring member 94 and the shield ring 95 are replaced by a low residual magnetic material corresponding to the outer rotor cup 17. Is an integral cup 117 comprising an end wall 117A and a peripheral wall 117B.

In the case of the two embodiments of FIGS. 7 and 8, the magnetically acting stator and rotor parts of the drive motor are
It is in the space surrounded by the disk support 110.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG.
II-II sectional view of the drawing, FIG. 3 is a sectional view showing another embodiment of the device of the present invention shown in FIG. 2, and FIGS. 4 to 8 show still another embodiment of the present invention. It is an axial sectional view. 10 ... Stator laminate, 10A ... Rotating shaft, 11A to 11F ...
… Stator poles, 12A to 12F …… Magnetic pole pieces, 13 …… Motor magnets, 17 …… Magnetic circuit member (outer rotor cup), 17B…
… Peripheral wall, 18 …… Drive motor, 19 …… Stator, 20A to 2
0F …… stator groove, 21 or 26 …… stator winding, 31 …… bearing bush, 32 …… shaft, 33 …… bearing, 36,36 ′ …… disk support, 37,37 ′ …… boss , 38 …… Printed circuit board,
39 ... Storage disk, 42, 43, 44 ... Rotational position sensor device, 45 ... Control magnet, 49 ... Clean room, 64 ... Boss, 65 ...
… Bearing bush, 66 …… Disk support, 72, 72 ′ ……
Magnetic liquid seal, 94 …… Magnetic circuit ring member, 95 …… Shield ring, 99 …… Boss, 100 …… Bearing bush, 102 ……
Disk support, 105 ... Fixed shaft, 106 ... Bearing, 107 ...
… Boss, 110 …… Disk support, 113 …… Bearing, 115…
… Conductive wire, 117 …… Back cover, 117B… Surrounding wall.

 ─────────────────────────────────────────────────── --Continued from the front page (56) Reference JP-A-57-53876 (JP, A) JP-A-56-166760 (JP, A) JP-A-56-107364 (JP, A) Actual development Sho-59- 1190 (JP, U)

Claims (16)

[Claims] 1. A stator having a winding, an outer rotor having an electric motor magnet of a permanent magnet, which surrounds the stator coaxially by forming a substantially cylindrical air gap, and a soft magnetic magnetic circuit member. A non-collective electronic drive motor and a boss that is concentrically connected to the magnetic circuit member and is non-rotatably coupled to the magnetic circuit member. In a disk drive device including a boss having a disk support portion that can be inserted into the center hole, and a stator winding and a motor magnet that operates in cooperation with the stator winding, a substantial main part of the motor magnet is in an axial dimension. A surface of a cylindrical portion and / or a flat surface portion which is provided inside a space surrounded by the disc support portion and which forms an outer peripheral surface of the disc support portion after the drive motor and the boss are assembled. A disk drive device in which the surface is superfinished for centering with the rotation axis. 2. The windings (21 to 26) of the stator and the motor magnets (13) operating in cooperation therewith are almost completely surrounded by the disk support (36, 36 ', 66, 102, 110). The disk drive device according to claim 1, characterized in that the disk drive device is provided inside a space (46) formed therein. 3. A disk supporting portion (36, 36 ', 66, 102, 11)
The wall thickness of (0) is equal to or smaller than the wall thickness of the portion (17B, 94, 117B) concentric with the disk supporting portion of the magnetic circuit member, or The disk drive device according to the second aspect. 4. A disk supporting portion (36, 36 ', 66, 102, 11).
The disk drive device according to any one of claims 1 to 3, wherein 0) has a cylindrical outer peripheral surface. 5. A boss (37, 37 ', 64, 99, 107) made of a material suitable for a clean room even after machining, such as light metal, according to claims 1 to 4. 2. The disk drive device according to any one of 1. 6. A disk supporting portion (36, 36 ', 66, 102, 11).
The superfinishing of the surface of 0) is performed by polishing or turning.
The disk drive device according to any one of items. 7. A boss (37, 37 ', 64, 99, 107) is formed by extrusion molding or casting, and a magnetic circuit member (17,
The disk drive device according to any one of claims 1 to 6, wherein the disk drive device is thermocompression-bonded to the disk drive device (94, 117). 8. A magnetic circuit member (94) is formed in an annular shape, and a magnetic shielding ring (95) extending radially inward from an axial end of the annular magnetic circuit member (94) on the clean room side, The disk drive device according to any one of claims 1 to 7, wherein the disk drive device is provided in the boss (99, 107). 9. An outer rotor (30) and bosses (37, 37 ', 6).
4, 99) is fixedly connected to a shaft (32) rotatably supported on a bearing device (33) at least partially provided in the stator (19) of the drive motor (18), The bearing bushes (31, 65, 100) that house the shaft (32) are replaced by the bosses (64, 99).
Alternatively, the disk drive device according to any one of claims 1 to 8, which is integrally formed with the magnetic circuit member (17). 10. The bearing device (33, 106, 113) comprises a clean room (49) with at least one magnetic fluid seal (72, 72 ').
10. The disk drive device according to claim 9, wherein the disk drive device is hermetically sealed against. 11. A printed circuit board (38) axially opposed to an axially open side of a unit including an outer rotor and a boss.
And a control magnet (45) for cooperating with a static magnetic sensing type rotary position sensor device (42, 43, 44) mounted on the printed circuit board, is coupled to the unit. The disk drive device according to any one of claims 1 to 10. 12. The invention according to claim 1, wherein the surface of at least the cylindrical portion formed on the outer peripheral surface of the disc support portion is superfinished after the drive motor and the boss are assembled. Disk drive. 13. A stator having a winding, an outer rotor having a motor magnet of a permanent magnet that surrounds the stator coaxially by forming a substantially cylindrical gap, a fixed shaft attached to a disk drive, and A non-collecting electronic drive motor equipped with a soft magnetic magnetic circuit member is rotatably supported on a fixed shaft through a bearing device, and is concentrically and non-rotatably coupled to the magnetic circuit member. A boss having a disk support portion that can be inserted into the central hole of the storage disk for accommodating at least one storage disk provided in the clean room, and The winding and the electric motor magnet that operates in cooperation with the winding are provided inside the space surrounded by the disk support portion, the substantial main portion of which is in the axial dimension, and the drive electric motor. After assembling the machine and the boss, the surface of the cylindrical portion and / or the flat portion forming the outer peripheral surface of the disc support portion is superfinished for centering with the rotation axis. Disk drive device. 14. The disk drive device according to claim 13, wherein the boss (107) is made of a material suitable for a clean room even after machining, such as light metal. 15. An outer rotor (30) and a boss (107) are rotatably supported on a fixed shaft (105) via bearing devices (106, 113), and the stator winding (21 to 26) Conductor (11
14. The disk drive device according to claim 13, wherein 5) is pulled out of the drive device through a fixed shaft (105). 16. A method according to claim 15, characterized in that the bearing device (106,113) is sealed to the clean room (49) by at least one magnetic fluid seal (72,72 '). Disk drive.