JPH09312058A - Spindle motor for flexible disk drive and its balance adjusting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spindle motor capable of stably rotating a magnetic disk even during high-speed rotation. SOLUTION: The magnetic disk medium of a flexible disk is attached to a rotor rotated around a rotary shaft A and, as a balancing means, a balancer 130 is attached to the lower surface of a magnet case 110. Thus, the centroid of the rotor is made coincident with the rotary shaft A and, during rotation (in particular, during high-speed rotation), the rotor is balanced. Accordingly, the magnetic disk is stably rotated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible disk drive, and more particularly to a spindle motor for rotating a flexible disk inserted in the flexible disk drive and a balance adjusting method thereof.

[0002]

2. Description of the Related Art As is well known, a flexible disk drive is a device for recording / reproducing a flexible disk inserted therein. In recent years, the capacity of a flexible disk has been increased, and a storage capacity of 128 Mbytes (hereinafter, referred to as a large capacity) is compared with a storage capacity of 1 M to 2 Mbytes (hereinafter, referred to as a normal capacity).
Those with are being developed. Along with this, a flexible disk drive capable of recording and reproducing such a large-capacity flexible disk has been developed.

In the following, a flexible disk drive capable of recording and reproducing data only on a magnetic disk medium of a large-capacity flexible disk is referred to as a high-density-dedicated flexible disk drive. A flexible disk drive capable of recording and reproducing data will be referred to as a normal-density-only flexible disk drive. Furthermore, a flexible disk drive capable of recording and reproducing data on magnetic disk media of both large-capacity and normal-capacity flexible disks has a high density / high density.
It is usually referred to as a dual-purpose flexible disk drive. When the high-density dedicated flexible disk drive and the high-density / normal density combined-type flexible disk drive are not distinguished, they are simply referred to as the high-density flexible disk drive.

One of the major mechanical differences between the normal-density dedicated type flexible disk drive and the high-density type flexible disk drive is that the carriage holding the magnetic head is inserted into the flexible disk drive. The drive means is configured to move along a predetermined radial direction (radial direction of the magnetic disk medium) with respect to the disk.
That is, while a stepping motor is used as a driving means in a normal-density type flexible disk drive, a linear motor such as a voice coil motor (VCM) is used as a driving means in a high-density type flexible disk drive. I have.

The voice coil motor used as the driving means for the high-density flexible disk drive will be described in detail below. The voice coil motor is arranged behind the carriage and has a voice coil wound around a drive shaft parallel to a predetermined radial direction, and a magnetic circuit for generating a magnetic field intersecting with a current flowing through the voice coil. Have. With such a configuration, a current is passed through the voice coil in a direction intersecting with the magnetic field generated by the magnetic circuit, and a driving force is generated in the extending direction of the drive shaft based on the interaction between the current and the magnetic field. . With this driving force, the voice coil motor moves the carriage along a predetermined radial direction.

Another difference between the normal density dedicated type flexible disk drive and the high density type flexible disk drive lies in the number of rotations of the spindle motor for rotating the inserted flexible disk drive. That is, in the normal density dedicated type flexible disk drive, since the flexible disk to be inserted is limited to the normal capacity flexible disk, the spindle motor therefor uses the magnetic disk medium of the inserted flexible disk at 300 rpm or 360 r.
It suffices to rotate at a rotation speed of pm. On the other hand, in the high density type flexible disk drive, the flexible disk to be inserted may be only the large capacity flexible disk or both the large capacity flexible disk and the normal capacity flexible disk. Therefore, when the inserted flexible disk is a large-capacity flexible disk, the spindle motor for the high-density flexible disk drive drives the magnetic disk medium 36
00 rpm and one of that of a normal capacity flexible disk
It must be rotated 2 to 10 times.

A spindle motor used in a conventional flexible disk drive will be described below with reference to FIG. In FIG. 7, (A) is a plan view,
(B) It is sectional drawing which cut | disconnected the rotor side by the AA line and the stator side by the BB line.

The illustrated spindle motor 100 'is of a type mounted on the surface of the main frame 11 (that is, the surface on which a flexible disk (not shown) is inserted) rather than the back surface of the main frame 11. In particular, it is a type that is mounted in the recess 11a of the main frame 11.

The main frame 11 has a substantially cylindrical bearing metal 102 in the recess 11a.
Are erected substantially perpendicular to the main surface of the main frame 11. In the bearing metal 102, a spindle shaft 104 is provided with a ball bearing 106 in a state substantially perpendicular to the main surface of the main frame 11.
And is rotatably supported by the main frame 11 via the. The spindle shaft 104 functions as a rotation axis A of a magnetic disk medium of a flexible disk (not shown) inserted in the flexible disk drive. A disc-shaped disc table 12 is fitted on the upper end side of the spindle shaft 104.
The main surface of the is extending in a direction orthogonal to the longitudinal direction of the spindle shaft 104 (direction of the central axis A).

That is, the disc table 12 is rotatably supported on the surface of the main frame 11, and holds the flexible discs inserted in the flexible disc drive in a state where their suspension axes (rotation axes A) are aligned with each other. .

Although not shown, as is well known, the flexible disk has a magnetic disk medium as a magnetic recording medium, and an upper case and a lower case that cover the magnetic disk medium from the upper side and the lower side, respectively. .
A circular opening is formed in the center of the lower case. In this circular opening, a disk-shaped metal fitting for holding the magnetic disk medium is loosely inserted. The disk-shaped metal fitting has a central hole at the center thereof through which the spindle shaft 104 is loosely inserted, and a disk-side drive elongated hole at a peripheral position deviated from the central hole, through which a drive roller described later is loosely inserted. Has been drilled.

The diameter of the disk table 12 is longer than the diameter of the disc-shaped metal fitting and shorter than the diameter of the circular opening.

The disk table 12 has a table-side driving slot 12a at a position corresponding to the disk-side driving slot.
Has been drilled. The drive roller 108 freely penetrates through the table-side driving long hole 12a. The drive roller 108 is a flexible arm 11 of a magnet case 110 attached to the lower surface of the disk table 12.
It is rotatably attached to one end of 2 via a holding portion 114 while being urged upward. Therefore, when a load is applied to the drive roller 108 from above, the drive roller 108 moves downward.

The magnet case 110 is made of iron,
The disk portion 116 is formed in a substantially tray shape by pressing and extends in parallel to the direction in which the disk table 12 extends, and an outer peripheral wall 118 bent downward around the outer periphery of the disk portion 116. A ring-shaped main magnet 120 is fixed to the inner side surface of the outer peripheral wall 118.

At any rate, the spindle motor 100 is constituted by the spindle shaft 104, the disc table 12, the drive roller 108, the magnet case 110, the arm 112, the holding portion 114, and the main magnet 120.
′ 'Rotor is configured.

The bearing metal 102 has a flange portion 102a. A core 122 is fixed and mounted on the flange portion 102a by a screw (not shown). The core 122 has a plurality of magnetic pole forming portions 122a extending radially at equal intervals. A coil 124 is wound around each magnetic pole forming part 122a. That is, the magnetic pole forming portion 122a
And the coil 124 are combined to form an electromagnet (magnetic pole)
Is formed. This electromagnet has a predetermined gap
The main magnet 120 is disposed so as to face the above. In any case, the core 122 and the coil 124 form a stator of the spindle motor 100 '.

Although not shown, the magnet case 1
A substantially rectangular parallelepiped index detecting magnet is fixed at an arbitrary position on the outer side surface of the outer peripheral wall 118 of the reference numeral 10.
A printed circuit board 126 is fixedly housed in the recess 11a of the main frame 11 with screws (not shown). A magnetic sensor (not shown) that detects magnetism from the index detecting magnet is arranged on the printed circuit board 126.

[0018]

As described above, the rotor of the spindle motor 100 'includes the spindle shaft 104, the disk table 12, and the drive roller 108.
, Magnet case 110, arm 112, and holding part 11
4 and the main magnet 120. That is, the rotor of the spindle motor 100 'is
Drive roller 108, arm 112 and holding portion 11
4 does not have a rotationally symmetric shape. In other words, the center of gravity of the rotor of the spindle motor 100 'is
The rotor of the spindle motor 100 'is not balanced because it is at a position displaced from the rotation axis A of the magnetic disk medium of the flexible disk to the drive roller 108 side.

When the flexible disk inserted in the flexible disk drive is a normal capacity flexible disk, the spindle motor 100 'may rotate its magnetic disk medium at a low speed of 300 rpm or 360 rpm. Even if the rotor is not balanced, the magnetic disk medium of the normal capacity flexible disk can be stably rotated without any problem.

However, when the flexible disk inserted in the flexible disk drive is a large capacity flexible disk, the spindle motor 100 'must rotate the magnetic disk medium at a high speed of 3600 rpm. As described above, when the magnetic disk medium is rotated at a high speed, if the rotor of the spindle motor 100 'is not balanced, the spindle motor 100' stably rotates the magnetic disk medium of the large-capacity flexible disk. Becomes difficult.

Therefore, in view of the above-mentioned conventional problems, an object of the present invention is to provide a spindle motor for a flexible disk drive which can stably rotate a magnetic disk medium even when the magnetic disk medium is rotated at a high speed. To provide.

Another object of the present invention is to provide a method for balancing the rotor of a spindle motor for a flexible disk drive.

[0023]

According to the present invention, there is provided a spindle motor for rotating a magnetic disk medium of a flexible disk inserted in a flexible disk drive, wherein the spindle motor is a magnetic disk of the flexible disk. A disk table that includes a rotor that rotates a disk medium around a rotation axis and a stator that is attached to a main frame and applies a rotational force to the rotor, the rotor holding a disk-shaped metal fitting of the flexible disk. A magnet case attached to the lower surface of the disc table; a spindle shaft inserted into the center hole of the disc-shaped metal fitting and concentric with the rotary shaft; a position eccentrically located from the spindle shaft,
A spindle motor for a flexible disk drive, comprising: a drive roller that penetrates through a long hole for driving the table side formed in the disk table and is inserted into the long hole for driving the disk side of the disk-shaped metal fitting of the flexible disk. According to another aspect of the present invention, there is provided a spindle motor for a flexible disk drive, characterized in that the rotor is provided with a balance means for aligning a center of gravity of the rotor with a rotation axis in order to balance the rotor during rotation.

According to the present invention, a spindle motor for rotating a magnetic disk medium of a flexible disk inserted in a flexible disk drive,
A method for balancing a rotor that rotates a magnetic disk medium of the flexible disk around a rotation axis, the roller comprising: a disk table holding a circular metal fitting of the flexible disk; and a roller attached to a lower surface of the disk table. A magnet case; a spindle shaft that is inserted into the center hole of the circular metal fitting and is concentric with the rotating shaft; and a position that is eccentrically located from the spindle shaft. A drive roller inserted through the disk-side driving long hole of the disc fitting of the flexible disk; and the balance adjusting method is a balance for balancing the rotor during rotation. Means for aligning the center of gravity of the rotor with the axis of rotation. Balance adjustment method can be obtained.

[0025]

Embodiments of the present invention will be described below in detail with reference to the drawings.

A flexible disk drive equipped with a spindle motor according to the present invention will be described with reference to FIG. The illustrated flexible disk drive (FD)
D) is a device for recording / reproducing data on / from a flexible disk (not shown). The flexible disk is inserted into the flexible disk drive from the direction indicated by arrow C in FIG. The inserted flexible disk is held on the disk table 12 rotatably supported on the surface of the main frame 11 with their central axes aligned with each other. The disk table 12 is rotationally driven by a spindle motor (described later) provided in a recess 11a (FIG. 7) of the main frame 11 so that the flexible disk is rotated. A printed wiring board (not shown) on which a large number of electronic components are mounted is attached to the back surface of the main frame 11.

The flexible disk drive has a magnetic head (not shown) for reading / writing data from / to the flexible disk. The magnetic head is held by a carriage 15 via a gimbal 14. Magnetic head, gimbal 14, carriage 15, voice coil 17 (described later), and FPC (flexible
A combination of a printed circuit, a scale, a spring holder and a spring is called a carriage assembly. The carriage 15 is arranged on the surface of the main frame 11 so as to be separated from the main frame 11, and allows the magnetic head to move along a predetermined radial direction (direction shown by arrow D in FIG. 6) with respect to the flexible disk. keeping.

The carriage 15 is supported and guided at its lower ends by a pair of guide bars 16 extending parallel to a predetermined radial direction D.

The carriage 15 is driven along a predetermined radial direction D by a voice coil motor as described below. More specifically, the voice coil motor is disposed behind the carriage 15 and has a predetermined radial direction D.
It has a pair of voice coils 17 wound around a drive axis parallel to and a magnetic circuit 20 for generating a magnetic field intersecting with the current flowing through the boil coil 17.
In the voice coil motor having such a configuration, a current is caused to flow through the boil coil 17 in a direction crossing the magnetic field generated by the magnetic circuit 20, so that the direction of extension of the drive shaft is determined based on the interaction between the current and the magnetic field. A driving force is generated.
This driving force causes the voice coil motor to move the carriage 1
5 is moved along a predetermined radial direction D.

FIG. 1 shows a spindle motor 100 according to the first embodiment of the present invention. The illustrated spindle motor has the same configuration as that of the conventional one shown in FIG. 7, except that the spindle motor shown in FIG.

The balancer 130 is the spindle shaft 1
It is attached to the lower surface of the magnet case 110 on the side opposite to the drive roller 108 with 04 in between. As a result, the center of gravity G of the rotor can be matched with the rotation axis A, and the rotor can be balanced during rotation (particularly during high-speed rotation).

Referring to FIG. 2, a spindle motor 100 according to a second embodiment of the present invention is similar to that shown in FIG. 7 except that the shape of the magnet case is changed and a balance means is added. It has the same configuration as the conventional one shown. Therefore, the reference numeral 1 is attached to the magnet case.
10A is attached.

Disc portion 116 of magnet case 110A
A ring-shaped groove 116a is formed in the outer peripheral portion of the. In the second embodiment, the balance arranging portion 130A arranged in the groove 116a of the magnet case 110A is used as the balance means. With such a structure, as in the first embodiment, the center of gravity G of the rotor can be aligned with the rotation axis A, and the rotor can be balanced during rotation (particularly during high speed rotation).

Referring to FIG. 3, a spindle motor 100B according to a third embodiment of the present invention is the same as the conventional one shown in FIG. 7, except that a balancing notch 130B is provided as a balancing means. It has a configuration similar to that of

In the illustrated example, the balance notch 130B
Is formed on the magnet case 110 on the same side as the drive roller 108 with respect to the spindle shaft 104. By forming the balancing notch 130B on the magnet case 110, the center of gravity G of the rotor can be aligned with the rotation axis A, and the rotor can be balanced during rotation (particularly during high-speed rotation).

In the example of FIG. 3, the balance notch 13
Although 0B is formed on the magnet case 110, it may be formed only on the disk table 12 or on both the magnet case 110 and the disk table 12 instead. Further, the number of the balance cutout 130B is not limited to one.

Referring to FIG. 4, a spindle motor 100C according to a fourth embodiment of the present invention is different from the conventional one shown in FIG. 7 except that a balancing hole 130C is provided as a balancing means. It has the same configuration as that of the one.

In the illustrated example, the balancing hole 130C is
Drive roller 1 to spindle shaft 104
It is formed on the magnet case 110 on the same side as 08. By forming the balancing hole 130C in the magnet case 110, the center of gravity G of the rotor can be aligned with the rotation axis A, and the rotor can be balanced during rotation (particularly during high speed rotation).

In the example of FIG. 4, the balancing hole 130C is formed.
Although it is formed on the magnet case 110, it may be formed on only the disk table 12 or on both the magnet case 110 and the disk table 12 instead. The number of balancing holes 130C is not limited to one.

Referring to FIG. 5, a spindle motor 100D according to a fifth embodiment of the present invention is shown in FIG. 7 except that the index detecting magnet 130D is also used as a balancer as a balance means. It has the same structure as the conventional one.

That is, in the fifth embodiment, the index detecting magnet 130D is fixed to the outer side surface of the outer peripheral wall 118 of the magnet case 110. The index detecting magnet 130D is attached to the spindle shaft 104. The rotor is balanced by providing it at a position on the opposite side of the drive roller 108 with it sandwiched therebetween. As a result, the center of gravity G of the rotor is aligned with the rotation axis A.

Conventionally, the index detecting magnet 130D is provided on the outer peripheral wall 11 of the magnet case 110.
8 was fixed at an arbitrary position on the outer side surface. In the present embodiment, the index detecting magnet 130D is provided at a specific position where the rotor is balanced.

The present invention is not limited to the above-mentioned embodiments, and it goes without saying that various changes and modifications can be made without departing from the spirit of the present invention. That is, any means for balancing the rotor is included in the scope of the present invention.

[0044]

As is apparent from the above description, according to the present invention, the rotor is provided with the balance means so that the center of gravity of the rotor coincides with the rotation axis of the magnetic disk medium, so that the magnetic disk medium rotates. In some cases (especially when rotating at high speeds) the rotor can be balanced. As a result, the magnetic disk medium can be stably rotated even at high speed.

[Brief description of drawings]

FIG. 1 is a diagram showing a spindle motor according to a first embodiment of the present invention, (A) is a plan view, (B) is a rotor side cut along an AA line, and a stator side is cut along a BB line. FIG.

2A and 2B are views showing a spindle motor according to a second embodiment of the present invention, in which FIG. 2A is a plan view, FIG. 2B is a sectional view taken along the line AA on the rotor side and a line BB on the stator side. FIG.

3A and 3B are views showing a spindle motor according to a third embodiment of the present invention, in which FIG. 3A is a plan view, FIG. 3B is a sectional view taken along the line A-A on the rotor side and a line B-B on the stator side. FIG.

4A and 4B are views showing a spindle motor according to a fourth embodiment of the present invention, in which FIG. 4A is a plan view, FIG. FIG.

5A and 5B are views showing a spindle motor according to a fifth embodiment of the present invention, in which FIG. 5A is a plan view and FIG. 5B is a sectional view taken along the line AA on the rotor side and taken along the line BB on the stator side. FIG.

FIG. 6 is a plan view showing a flexible disk drive including a spindle motor according to the present invention.

7A and 7B are views showing a conventional spindle motor, in which FIG. 7A is a plan view, and FIG. 7B is a cross-sectional view taken along line AA on the rotor side and line BB on the stator side.

[Explanation of symbols]

 130 Balancer 130A Assembling part 130B Balance notch 130C Balance hole 130D Index detecting magnet

Front Page Continuation (72) Inventor Yoshinori Tanki 1601 Sakai, Atsugi, Kanagawa Mitsumi Electric Co., Ltd. Atsugi Plant

Claims (12)

[Claims] 1. A spindle motor for rotating a magnetic disk medium of a flexible disk inserted in a flexible disk drive, the spindle motor rotating the magnetic disk medium of the flexible disk around a rotation axis. The rotor includes a rotor and a stator that is attached to the main frame and applies a rotational force to the rotor. The rotor is mounted on the lower surface of the disk table that holds the disk-shaped metal fitting of the flexible disk. A magnet case, a spindle shaft inserted into the center hole of the disk-shaped metal fitting, concentric with the rotary shaft, and a table-side driving long hole formed in the disk table at a position eccentrically located from the spindle shaft. Disc-shaped metal of the flexible disk A spindle motor for a flexible disk drive, comprising: a drive roller inserted into a disk-side driving long hole of a tool; and a center of gravity of the rotor on a rotation axis in order to balance the rotor during rotation. A spindle motor for a flexible disk drive, which is provided with a balancing means for matching. 2. The spindle motor for a flexible disk drive according to claim 1, wherein the balance means is a balancer attached to a lower surface of the magnet case. 3. A ring-shaped groove is formed on an outer peripheral portion of the magnet case, and the balance means is a balance arranging portion arranged in the groove of the magnet case. The spindle motor for a flexible disk drive according to claim 1, which is characterized in that. 4. The spindle motor for a flexible disk drive according to claim 1, wherein the balancing means is a notch for balancing provided in the magnet case and / or the disk table. 5. The spindle motor for a flexible disk drive according to claim 1, wherein the balancing means is a balancing hole formed in the rotor. 6. An index detecting magnet is fixed to the magnet case, and the balance means is the index detecting magnet provided at a position for balancing the rotor, and the index detecting magnet is a balancer. The spindle motor for a flexible disk drive according to claim 1, wherein the spindle motor is also used as. 7. A method for balancing a rotor of a spindle motor for rotating a magnetic disk medium of a flexible disk inserted in a flexible disk drive, the rotor rotating the magnetic disk medium of the flexible disk around a rotation axis. The roller includes a disk table for holding the circular metal fitting of the flexible disk, a magnet case attached to the lower surface of the disk table, and a spindle which is inserted into the center hole of the circular metal fitting and is concentric with the rotating shaft. A shaft and a drive which is located at a position eccentrically located from the spindle shaft and which freely penetrates through a table-side driving slot formed in the disk table and is inserted into the disk-side driving slot of the disc fitting of the flexible disk. A roller, and the balance adjusting method. By providing a balance means for balancing the rotor in rotation to the rotor, balance adjustment method which is characterized in that to match the center of gravity of the rotor to the rotating shaft. 8. The balance adjusting method according to claim 7, wherein a balancer is attached to the lower surface of the magnet case as the balance means. 9. A ring-shaped groove is formed on an outer peripheral portion of the magnet case, and a balance arranging portion is arranged in the groove of the magnet case as the balance means. The balance adjusting method according to claim 7. 10. The balance adjusting method according to claim 7, wherein a balance cutout is formed in the magnet case and / or the disk table as the balance means. 11. The balancing hole is formed in the rotor as the balancing means.
Balance adjustment method described in. 12. An index detecting magnet is fixed to the magnet case, the index detecting magnet is provided at a position for balancing the rotor as the balancing means, and the index detecting magnet is a balancer. 8. The balance adjusting method according to claim 7, wherein the balance adjusting method is also used.