JPH0974705A - Disk driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the read-write performance of a disk by a head mechanism by preventing the run-out of a shaft and obviating a surface swing to the head mechanism of the disk. SOLUTION: A disk driving device has a spindle motor with a turntable 4, a shaft 5 fitted at the center of the turntable 4, a metal bearing 6 rotatably bearing the shaft 5, a rotor case 7 integrally rotated with the shaft 5, a driving magnet 8 fixed onto the rotor case 7, and a stator core 9, which has a plurality of salient poles 9a and in which coils 10 are wound on these salient poles 9a while the outer circumferential surfaces of the salient poles 9a are arranged oppositely to the inner circumferential surface of the driving magnet 8. The shaft 5 is deviated in approximately the same direction as the direction of movement of a head mechanism.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk drive device, and in particular, a disk such as a compact disk, a magneto-optical disk, a mini disk, a hard disk, and a floppy disk is rotationally driven and recorded on the disk by a head mechanism. Related to reproducing / recording information.

[0002]

2. Description of the Related Art In a disk drive device for reading / writing (reproducing / recording) information recorded on a disk by a head mechanism, the cost is kept low as a bearing device for rotatably supporting a shaft fitted to a turntable. Therefore, a metal bearing made of a sintered material or the like is widely used instead of a ball bearing. To drive the shaft to rotate,
There is a slight clearance between the metal bearing and the shaft, but this clearance causes the shaft to run out, which causes a runout on the surface of the disk that is placed on the turntable and driven to rotate. In some cases, the head mechanism could not read or write information accurately.

Various techniques have been proposed as means for preventing the runout of the shaft when the metal bearing as described above is used. For example, in Japanese Utility Model Laid-Open No. 6-080373, the relationship between the salient poles of the stator core and the magnetic pole center in the thrust direction of the drive magnet is arranged to be non-parallel. In order to make the relationship between the salient poles of the stator core and the magnetic pole center in the thrust direction of the drive magnet non-parallel, a spacer is interposed in a part of the core holder, or a salient pole of a part of the stator core is bent. There is. By doing so, the central shaft is biased in a certain direction, and the outer peripheral surface of the central shaft is rotationally driven in such a manner as to come into contact with the inner peripheral surface of the bearing,
The central shaft is rotationally driven without center runout, and surface runout does not occur in the rotationally driven disk.

[0004]

Even if the central axis is biased in a certain direction and the outer peripheral surface of the central axis is in contact with the inner peripheral surface of the bearing, it is impossible to completely suppress the runout. It is possible. This is because there is a slight clearance even at a position adjacent to the direction in which the central axis is deviated, so that the central axis deviates within the range of this clearance. However, since the surface wobbling of the disk due to such a center wobbling does not affect the information reading / writing performance of the head mechanism, it has not been so important in the past.

However, as shown in FIG. 12, when the center axis J is deviated in the N direction which is orthogonal to the moving direction M of the head mechanism, a center runout caused by a slight clearance C adjacent to the center axis J is generated. This occurs in the same direction as the moving direction M of the head mechanism. The center run-out that occurs in the same direction as the moving direction M of the head mechanism causes the disk to run out in the same direction as the moving direction M of the head mechanism, so the run-out is not improved with respect to the head mechanism, and the information due to the head mechanism Will adversely affect the read and write performance of. The symbol O indicates the center of rotation of the central axis J, and the symbols O ′ and O ″ indicate the center of rotation when the central axis J is the most centered.

Further, the disk drive device is usually used in such a posture that the disk D is horizontal as shown in FIG. However, depending on the main body device or the like to which the disc drive device is attached, the disc drive device shown in FIG. 13 (a) is placed vertically and the posture shown in FIGS. Sometimes used. When such a disk drive device is installed vertically, as described above, when the central axis J is biased in the direction orthogonal to the moving direction M of the head mechanism, the biased direction of the central axis J is the upper side. Sometimes. When the biased direction of the central axis is on the upper side, the central axis J biased on the upper side is returned to the opposite side by gravity K as shown in FIG.
The central axis J is not biased to the bearing side.
Therefore, the central axis J does not come into contact with the inner peripheral surface of the bearing, so that a large clearance is generated, and due to this clearance, the central axis oscillates in a pestle-like manner, which causes surface wobbling of the disk, and the head mechanism moves the disk. It had an adverse effect on reading and writing performance.

The present invention has been made to solve the above-mentioned problems of the prior art, and eliminates the runout of the shaft and the runout of the disk with respect to the head mechanism.
An object of the present invention is to provide a disk drive device with improved disk read / write performance by a head mechanism.

[0008]

According to the first aspect of the present invention,
A disc-shaped disc on which information is recorded, a head mechanism for reproducing / recording information recorded on the disc by approaching the disc by a linear seek motion, and a spindle motor that is loaded with the disc and is driven to rotate. The motor includes a turntable on which the disc is mounted, a shaft fitted in the center of the turntable, a metal bearing that rotatably supports the shaft, a cup-shaped rotor case that rotates integrally with the shaft, and an inner peripheral surface of the rotor case. A drive magnet having a plurality of magnetic poles fixedly attached to each other, a plurality of radially projecting salient poles, and coils of multiple phases wound around these salient poles, and the outer peripheral surface of the salient poles being the inner peripheral surface of the drive magnet. And a stator core disposed so as to oppose to the disk drive, the shaft having substantially the same movement direction as the head mechanism. Characterized in that it is biased towards.

According to a second aspect of the present invention, the salient poles of the stator core are within a range of ± 90 ° with respect to the moving direction of the head mechanism, and the salient pole on one side of the moving direction of the head mechanism is on the upper side in the stacking direction. The salient pole having a tip end on the other side in the moving direction of the head mechanism is characterized in that the tip end on the lower side in the stacking direction is cut out, and the shaft is biased in the moving direction of the head mechanism.

According to a third aspect of the present invention, the number of cut-out tips of the stator core salient poles is half or less of the total number of laminated layers on one side and the other side in the moving direction of the head mechanism.

According to a fourth aspect of the present invention, the head mechanism is an optical pickup head.

According to a fifth aspect of the present invention, the spindle motor has a motor substrate that supports the metal bearing substantially vertically,
The motor board is inclined at a predetermined angle with respect to the mounting member, so that the shaft is substantially perpendicular to the motor board mounting member.

Since the shaft is biased in substantially the same direction as the moving direction of the head mechanism and is in contact with the inner peripheral surface of the metal bearing, the shaft does not move so much in the moving direction of the head mechanism.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a disk drive device according to the present invention will be described below with reference to the drawings. In FIGS. 1 and 2, a disk drive device mainly includes a spindle motor 3 on which a disk 1 is mounted and is driven to rotate, and a disk seek approaching the disk 1 by a linear seek motion to reproduce or record information recorded on the disk 1. It is composed of a head mechanism 2. The head mechanism 2 is an optical pickup head, and furthermore, two guide rails are provided on both sides. By this guide rail, the head mechanism 2 is moved in the radial direction of the disk 1, that is, in the direction indicated by the symbol M in the figure, and the information recorded on the surface of the disk 1 can be read and written.

Next, an embodiment of the spindle motor 4 for rotationally driving the disk 1 will be described. In FIG. 3, a hole 12a is formed in the center of the substrate 12, and the thrust bearing 11 is attached to the hole 12a. The thrust bearing 11 includes an upper large diameter portion and a lower small diameter portion, and the small diameter portion is fitted and fixed in the hole 12a.
A metal bearing 6 is mounted on the substrate 12 and on the outer circumference of the large diameter portion of the thrust bearing 11. The metal bearing 6 has a cylindrical shape and has a flange portion 6a on the outer peripheral surface on the lower side. The lower end surface of the flange portion 6a is attached to the upper end surface of the substrate 12. Further, the outer peripheral surface of the metal bearing 6 and the upper end surface of the flange portion 6a play the role of a core holder, and the inner peripheral surface of the stator core 9 is inserted into the outer peripheral surface of the metal bearing 6 and the lower end surface of the stator core 9 is covered. Part 6a
Is placed on the upper end surface of. Such a stator core 9
Is formed by stacking a plurality of magnetic plates, has salient poles 9a on the outer periphery, and each salient pole 9a has a coil 1
0 is wound. As shown in FIGS. 4 to 6, each salient pole 9a is composed of an umbrella portion 9c at the tip, and an arm portion connecting the umbrella portion 9c and the base portion of the stator core. The magnetic plates forming the stator core 9 do not all have the same shape. Some of the magnetic plates on the upper side in the stacking direction and some on the lower side in the stacking direction differ from the shape of the intermediate portion in the salient poles 9a. Several portions of the umbrella portion 9c are cut off. Two sets of notches A and B are formed in the stator core 9 by stacking such magnetic plates, the specific portions of which are cut off, on the upper side and the lower side in the stacking direction. Two sets of notches A,
Of B, the notch A is formed at the tip of the stator core 9 on the upper side in the stacking direction, and the notch B is formed on the tip of the stator core 9 on the lower side in the stacking direction. The number of magnetic plates cut out from the stator core 9 to form the notches A and B is set to half or less of the total number of laminated layers.

In FIG. 3, the inner peripheral surface 6b of the metal bearing 6 is shown.
The shaft 5 is inserted through the shaft. The outer peripheral surface of the shaft 5 is supported by the inner peripheral surface of the metal bearing 6 in the radial direction, and the lower end portion of the shaft 5 contacts the upper end portion of the thrust bearing 11 and is supported in the thrust direction. Therefore, the shaft 5 is rotatable with respect to the stator core 9, the metal bearing 6, and the like.

A disc-shaped turntable 4 is attached to the upper end of the shaft 5. Turntable 4
A boss portion 4b is provided at the center of the lower end surface side, and the boss portion 4b is fixed to the shaft 5. A projecting disc guide portion 4c is formed in the center of the upper end surface side of the turntable 4, and a concave portion 4d is formed in the disc guide portion 4c along a circle centered on the rotation center axis of the shaft 5. An attraction magnet 13 is attached in the recess 4d. Further, a jetty-shaped disc mounting portion 4a is formed on the edge portion on the upper end surface side of the turntable 4, and a disc rubber 15 is attached to the upper end surface of the disc mounting portion 4a.

A clamper (not shown) is arranged above the turntable 4. When the above-described disc 1 is placed on the turntable 4, the clamper descends and contacts the inner edge of the disc 1. Further, since the clamper is made of a magnetic material, it is magnetically attracted by the attraction magnet 13 and the disc 1 is pressed onto the turntable by the clamper, so that the disc 1 is kept fixed to the turntable 4.

A cup-shaped rotor case 7 is attached to the outer peripheral surface of the shaft 5, slightly above the upper end of the metal bearing 6 and below the turntable 4. A boss portion 7a is formed at the center of the flat plate-shaped portion of the rotor case 7, and the boss portion 7a is fixed to the shaft 5. The rotor case 7 has a peripheral wall 7b on the outer peripheral side, and the peripheral wall 7b covers the stator core 9 and the like from above. A drive magnet 8 is attached to the inner peripheral surface of the peripheral wall 7b, and the inner peripheral surface of the drive magnet 8 faces the salient poles 9a of the stator core 9 with a constant gap.
Therefore, the drive magnet 8 is energized by controlling the energization of the coil 10 wound around the salient pole 9a, and the rotor case 7, the shaft 5, the turntable 4, and the disk 1 fixed to the turntable 4 are integrated together. It is driven to rotate.

Note that the stator core 9 has notches A and B at the top end in the stacking direction and on the bottom end in the stacking direction. Therefore, the magnetic center 9d of the drive magnet 8 in the axial direction of the salient pole 9a in the portion where the notch A of the stator core 9 is formed does not coincide with the magnetic center 8a of the drive magnet 8, and the magnetic center 8a of the drive magnet 8 is on the upper side. It is a form that has shifted to.
Further, the magnetic center 9d in the axial direction of the salient pole 9a in the portion where the notch B of the stator core 9 is formed and the drive magnet 8 are formed.
The magnetic centers 8a of the drive magnets 8 do not match, and the magnetic center 8a of the drive magnet 8 is shifted downward. Therefore, since the magnetic force of the drive magnet 8 acts so that the magnetic center 8a and the magnetic centers 9d and 9d 'of the stator core 9 coincide with each other, as shown in FIG. The outer peripheral surface of the shaft 5 and a part of the outer peripheral surface of the shaft 5 are in contact with the inner peripheral surface of the metal bearing 6. Although the inclination of the shaft 5 is exaggerated in FIG. 7, this is not the case in reality, and at most 2-3 minutes (1
Min = 1/60 °).

In the spindle motor 3 as described above, the positions of the notches A and B of the stator core 9 are shown in FIGS.
As shown in FIG. 3, the moving direction M of the head mechanism 2 with respect to the shaft 5 is one side and the other side. In the stator core 9 on the upper side in the stacking direction shown in FIG. 4, a portion serving as the umbrella portion 9c of the magnetic plate within the range of ± 60 ° with respect to the moving direction M of the head mechanism 2 is cut off to form a notch A. There is. Further, in the stator core 9 on the lower side in the stacking direction shown in FIG. 6, a portion of the umbrella portion 9c of the magnetic plate which belongs to the range of ± 60 ° with respect to the moving direction M of the head mechanism 2 is cut off to form a notch B. Has been done. By doing so, the magnetic attraction force of the drive magnet 8 acts so that the magnetic center 8a and the magnetic centers 9d and 9d ′ of the stator core 9 coincide with each other, and as shown in FIG. The posture is biased to the moving direction M side.

As shown in FIG. 8, when the shaft 5 is biased toward the moving direction M of the head mechanism 2, a slight clearance C (1 to 6 μm) between the shaft 5 and the metal bearing 6 is produced.
The center runout caused by (m) is relatively large in the direction orthogonal to the moving direction M of the head mechanism 2, and the runout on the moving direction M side of the head mechanism 2 hardly occurs.
This is also clear from the data of the runout locus in the embodiment shown in FIGS. U direction,
That is, the core runout width in the moving direction M of the head mechanism 2 can be suppressed to about 1.4 μm even if it is large. In addition, P.
The center runout width in the direction perpendicular to U, that is, in the direction orthogonal to the moving direction M of the head mechanism 2 is relatively large at a maximum of 5.0 μm. There is almost no influence on the read / write performance of 1. However, the center runout width is a value in one embodiment and relatively changes depending on the situation. For example, when the number of rotations of the spindle motor changes, its swing width is also limited. Therefore, as described above,
By biasing the shaft 5 in a direction substantially the same as the moving direction M of the head mechanism 2, center deviation of the shaft 5 in the moving direction of the head mechanism 2 is prevented, and moreover, in the moving direction M of the head mechanism 2 of the disk 1. Head mechanism 2 by eliminating surface wobbling
The read / write performance of the disk 1 can be improved.

In the above embodiment, the head mechanism 2
The cutouts A and B were formed by cutting away the portion of the magnetic plate that would be the umbrella portion 9c within the range of ± 60 ° with respect to the moving direction M. However, it is not limited to this.
Even if the notches A and B are formed by cutting off the portion of the magnetic plate that becomes the umbrella portion 9c within the range of ± 90 ° with respect to the moving direction M of the head mechanism 2, the same effect as in the above-described embodiment is obtained. Play.

Further, since the shaft 5 is tilted and biased in a direction substantially the same as the moving direction M of the head mechanism 2, FIG.
As shown in FIGS. 3 (b) and 3 (c), the shaft 5 is not biased upward even if the disc device is placed vertically. Therefore, the shaft 5 does not return to the opposite side due to gravity and is not separated from the inner peripheral surface 6a of the metal bearing 6, and the shaft 5 can always maintain a biased position in the moving direction M of the head mechanism 2. it can.

Further, in the above embodiment, two sets of notches A and B are used on the moving direction M side of the head mechanism 2 with respect to the stator core 9 to bias the shaft 5, but the present invention is not limited to this. Only one of the notches A and B may be formed. Even with such a configuration, the shaft 5 can be biased toward the moving direction M side of the head mechanism 2, so that the center deviation of the shaft 5 in the moving direction M of the head mechanism 2 can be prevented and the head mechanism 2 of the disk 1 can be prevented. The surface wobbling in the moving direction M can be eliminated, and the read / write performance of the disk 1 by the head mechanism 2 can be improved.

Further, when the spindle motor 3 shown in FIGS. 3 and 7 is attached to the disk drive device, the substrate 12
May be attached to the mounting member at a predetermined angle to the moving direction M side of the head mechanism 2, that is, at the same angle as the deviation angle of the shaft 3. By doing so, the shaft 3 becomes substantially vertical to the end surface of the mounting member, and the end surface of the mounting member and the disc 2 mounted on the turntable 4 are mounted.
Are almost parallel.

[0027]

According to the present invention, since the shaft is biased in the substantially same direction as the moving direction of the head mechanism, the runout generated on the moving direction side of the head mechanism when the shaft is rotationally driven is suppressed. Therefore, it is possible to eliminate surface wobbling in the moving direction of the head mechanism of the disk and improve the read / write performance of the disk by the head mechanism.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of a disk drive device according to the present invention.

FIG. 2 is a side view of the same.

FIG. 3 is a sectional view showing an embodiment of a spindle motor applied to the same disk drive device.

FIG. 4 is a plan view showing an embodiment of a magnetic plate of a stator core applied to the above spindle motor.

FIG. 5 is a side view showing an embodiment of a stator core applied to the above spindle motor.

FIG. 6 is a plan view showing an embodiment of a magnetic plate of a stator core applied to the above spindle motor.

FIG. 7 is a sectional view showing a shaft deviation in a spindle motor applied to the same disk drive device.

FIG. 8 is a plan view showing a core deviation of a shaft in a spindle motor applied to the same disk drive device in an enlarged manner in a main portion.

FIG. 9 is a waveform diagram showing a center runout locus of a shaft in a spindle motor applied to the same disk drive device.

FIG. 10 is the same as the above, in the spindle motor applied to the disk drive device; The wave form diagram which shows the center runout in the U direction.

FIG. 11 is a spindle motor applied to the disk drive device of the same as above. The wave form diagram which shows the center run-out in the direction orthogonal to U.

FIG. 12 is a plan view showing an enlarged main part of an example of center runout of a center shaft in a spindle motor applied to a conventional disk drive device.

FIG. 13 is a front view showing an example of how to put a conventional disk drive device.

FIG. 14 is a side perspective view showing an example in which a conventional disk drive device is vertically installed.

[Explanation of symbols]

 1 Disk 2 Head Mechanism 3 Spindle Motor 4 Turntable 5 Shaft 6 Metal Bearing 7 Rotor Case 8 Drive Magnet 9 Stator Core 9a Salient Pole

Claims (5)

[Claims] 1. A disc-shaped disc on which information is recorded, a head mechanism for approaching the disc by a linear seek motion to reproduce or record the information recorded on the disc,
A spindle motor that is rotationally driven by mounting the disc is provided. The spindle motor includes a turntable on which the disc is mounted, a shaft fitted in the center of the turntable, and a metal that rotatably supports the shaft. A bearing, a cup-shaped rotor case that rotates integrally with the shaft, a drive magnet that is fixed to the inner peripheral surface of the rotor case and has a plurality of magnetic poles, and a plurality of radially protruding salient poles. And a stator core arranged such that an outer peripheral surface of a salient pole is opposed to an inner peripheral surface of the drive magnet, and the shaft is the head mechanism of the head mechanism. A disk drive device, which is biased in substantially the same direction as the moving direction. 2. A range of ± 9 with respect to the moving direction of the head mechanism.
In the salient poles of the stator core belonging to the range of 0 °, the salient pole on one side of the moving direction of the head mechanism is the tip end on the upper side in the stacking direction, and the salient pole on the other side of the moving direction of the head mechanism is the lower side in the stacking direction. The tip portion is notched, and the shaft is biased in the moving direction of the head mechanism.
The disk drive described. 3. The disk drive device according to claim 2, wherein the number of the stator core salient poles that are cut out at their tips is half or less of the total number of laminated layers on one side and the other side in the moving direction of the head mechanism. 4. The disk drive device according to claim 1, wherein the head mechanism is an optical pickup head. 5. The spindle motor has a motor substrate that supports a metal bearing substantially vertically, and the shaft is substantially perpendicular to the motor substrate mounting member by inclining the motor substrate at a predetermined angle with respect to the mounting member. The disk drive device according to claim 1 or 2, wherein