JPH0612803A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To provide a magnetic disk device provided with an inexpensive retracting structure having high reliability with a small occupancy space. CONSTITUTION:Over the whole moving area of a magnetic head 3, the leakage magnetic flux of a VCM attracts or repulses only the magnetic material 12 provided with a bobbin 13 consisting of non-magnetic material and the magnetic material 12 is provided on a position where attraction and repulsion are distributed to the angular moment of wholly negative or the angular moment of wholly positive against the rotational axis of a pivot bearing 4. Consequently, the attraction and repulsion of the magnetic material owing to the leakage magnetic flux of the VCM are transformed into rotational force for moving the magnetic head to a prescribed position at whole moving area. Also, since the device is simple in structure, the number of parts is lessen, and cost is reduced. Also, since a dedicated magnet is not used, reliability is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk device, and more particularly to a magnetic head retract system in a rotary actuator type magnetic disk device.

[0002]

2. Description of the Related Art When the rotation of a magnetic recording disk in a magnetic disk device is stopped, a magnetic head is moved to a portion on the magnetic recording disk where data is not recorded, that is, a shipping area and fixed at that position. There are various ways
It has been proposed in the past. Normally, when the magnetic recording disk rotates and the magnetic head is reading / writing data, the magnetic head is not in contact with the magnetic recording disk due to the air flow due to the rotation, and it slightly floats. ing.
However, when the rotation stops, the air flow also stops, so
The magnetic head and the magnetic recording disk come into contact with each other. If this contact occurs in the data area, the recorded data may be destroyed. Therefore, when the rotation of the magnetic recording disk is stopped, it is necessary for the magnetic head to complete the movement to the shipping area and fix it at that position (that is, retract operation).

As prior art relating to this, for example, Japanese Patent Application Laid-Open No. 61-269275 and Japanese Patent Application Laid-Open No. 3-86982.
As described in Japanese Patent Laid-Open Publication No. 2004-163, there is one in which a tension force of a spring spring or a leaf spring gives a force in one direction to an actuator, thereby moving a magnetic head to a predetermined position on a magnetic recording disk. Further, as a conventional technique of only fixing in the shipping area, Japanese Patent Laid-Open No. 62-245579.
As described in the publication, there is one in which an actuator is attracted and fixed by a dedicated magnet in a shipping area. Further, as described in Japanese Patent Application Laid-Open No. 2-214076, in addition to the attractive force of the leakage flux of the magnetic material and the VCM, it is caused by the reaction force of the flexible printed wiring board (FPC) and the inertial rotation of the spindle motor. There is a method in which an electric current is caused to flow through a VCM and a force by a magnetic force is used.

[0004]

According to the above-mentioned conventional technique, for example, the technique of moving the magnetic head to a predetermined position by a spring spring, it is troublesome to further attach the spring spring to a narrow installation space in the small magnetic disk drive. Therefore, the number of parts increases. Further, due to the compression wave vibration of the spring spring, a large amount of dust such as material powder and plating powder is generated from the spring spring body, and the dust enters the floating gap of the magnetic head, which causes a head crash. In addition, the vibration of the spring causes the carriage to resonate, and the vibration of the carriage causes the spring to break.
There is a problem that the carriage cannot be accessed due to the broken spring.

Further, according to the technique using the leaf spring, the problem of compressional wave vibration can be solved, but it is insufficient in terms of reducing the number of parts. Further, since the leaf spring is repeatedly bent, fatigue occurs in the bent portion, which may damage the leaf spring. Further, since the problem of bending fatigue is the problem of the life of the leaf spring, it may not be detected during the normal line inspection with a small number of bendings, and may occur in the future after the product is delivered to the customer.

Further, the technique of attracting and fixing the actuator with a dedicated magnet in the shipping area provides only the fixing means after the actuator has moved to this area, and the magnetic recording circle is used in the entire moving area of the magnetic head. It is not possible to automatically move it into place on the plate. In addition, there are still problems with the installation space and the number of parts.In addition, the dedicated magnet easily emits magnetic powder due to oxidation or shock, and if the generated magnetic powder adheres to the magnetic disk, the head may not crash. However, there is a problem that the data on the magnetic disk is completely destroyed by its magnetism. Furthermore, the strong magnetic flux leakage of the voice coil motor magnet changes the magnetic polarity and magnetic force of the dedicated magnet, making it impossible to attract and fix the actuator even if it exists in the area where it could be attracted and secured before the change. On the contrary, there is a possibility that the fixing force becomes stronger than necessary and the actuator cannot escape from the suction fixing region with a predetermined access force.

Further, in the technique which uses the reaction force of the FPC and the application of the counter electromotive force due to the inertial rotation of the motor to the VCM coil, there are restrictions on the arrangement of the FPC and the positions of the components mounted on the FPC. . Further, a circuit for applying the counter electromotive force and a changeover switch for using this circuit are required, an increase in the number of parts cannot be avoided, and eventually the magnetic disk device cannot be miniaturized.

It is an object of the present invention to eliminate the above-mentioned problems caused by the prior art, and to provide a magnetic disk device having a retract structure which is inexpensive and has a very small installation space and high reliability.

[0009]

In order to achieve the above object, a magnetic disk device according to the present invention is such that a coil holding portion (bobbin) of a voice coil motor is provided with a magnetic body for retracting a magnetic head. It is a feature of.

In the magnetic disk device of the first feature, the permanent magnet of the voice coil motor has a plane in the vicinity of the magnetic body which is perpendicular to the surface facing the coil, and a perpendicular line passing through the plane and the magnetic body. A second feature is that the straight line connecting the center position and the rotation axis of the carriage does not match within the entire moving area of the magnetic head, or is provided only at one position.

In the magnetic disk device of the first and second characteristics, the magnetic material is provided so that the magnetic head faces the inner circumferential direction of the magnetic recording disk when the magnetic disk is stopped. And

Further, in the magnetic disk device of the third feature, the center position of the magnetic body is a perpendicular line passing through a plane perpendicular to the surface of the permanent magnet of the voice coil motor facing the coil and from the center position of the magnetic body. The vector heading toward the center of the permanent magnet is provided so as to have a negative rotation moment with respect to the rotation axis of the carriage, and the magnetic head is rotated by the negative rotation with respect to the rotation axis of the carriage. The fourth feature is that the structure is provided so as to face the inner peripheral direction of the.

In the magnetic disk device of the third feature, the center position of the magnetic body is a vertical line passing through a plane of the permanent magnet of the voice coil motor which is perpendicular to the surface facing the coil, and from the center position of the magnetic body. The vector heading toward the center of the permanent magnet is provided so as to have a positive rotation moment with respect to the rotation axis of the carriage, and the magnetic head is rotated by the positive rotation with respect to the rotation axis of the carriage. The fifth feature is that it is provided so as to face the inner peripheral direction.

[0014]

In the magnetic disk device according to the first feature, the bobbin is made of a non-magnetic material, and the bobbin is partially provided with a magnetic material. From this, only the magnetic part of the bobbin is attracted by the leakage magnetic flux of the permanent magnet of the voice coil motor, and the attracting force is converted into a rotational moment for moving the magnetic head to a predetermined position.
Moreover, since the structure is simple and no dedicated magnet is used, the number of parts is small, the cost is low, and the reliability is high. Further, since the magnetic body can be provided at the height position between the air gaps of the voice coil motor, the retract structure can be provided in a smaller installation space.

In the magnetic disk device according to the second feature, the permanent magnet of the voice coil motor has a plane in the vicinity of the magnetic body, which is perpendicular to the surface facing the coil, and a perpendicular line passing through the plane and the magnetic body. The straight line connecting the center position of the carriage and the rotation axis of the carriage does not match within the entire moving area of the magnetic head, or is provided so as to match at only one position. The attraction force due to the magnetic flux leaking from the permanent magnet of the voice coil motor is converted into a rotational moment for moving the magnetic head to a predetermined position in the entire moving area of the magnetic head or in the necessary moving area. .

Further, in the magnetic disk device according to the third feature, the magnetic body is provided so that the magnetic head faces the inner peripheral direction of the magnetic recording disk when the magnetic disk is stopped. The magnetic head is moved to a shipping area provided on the inner circumference of the magnetic disk.

Further, in the magnetic disk drive according to the fourth feature, the center position of the magnetic body is a vertical line passing through a plane perpendicular to the surface of the permanent magnet of the voice coil motor facing the coil, and is approximately from the center position of the magnetic body. A vector heading toward the center of the permanent magnet is provided so as to have a negative rotation moment with respect to the rotation axis of the carriage, and the magnetic head is further rotated by the negative rotation with respect to the rotation axis of the carriage. Since the magnetic head is provided so as to face the inner circumferential direction, the direction of the rotational moment acting on the magnetic head is the direction in which the magnetic head moves on the inner circumferential side of the magnetic disk.

Further, in the magnetic disk drive according to the fifth feature, the center position of the magnetic body is a perpendicular line passing through a plane perpendicular to the surface of the permanent magnet of the voice coil motor facing the coil and from the center position of the magnetic body. The vector heading toward the center of the permanent magnet is provided so as to have a positive rotation moment with respect to the rotation axis of the carriage, and the magnetic head is rotated by the positive rotation with respect to the rotation axis of the carriage. Since the magnetic head is provided so as to face the inner circumferential direction of the magnetic head, the direction of the rotational moment acting on the magnetic head is the direction in which the magnetic head moves to the inner circumferential side of the magnetic disk.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a magnetic disk device according to the present invention will be described below in detail with reference to the drawings. FIG. 1 is a detailed view of the carriage portion of the magnetic disk device of this embodiment. FIG. 2 shows the head of the magnetic disk drive according to this embodiment. disk. FIG. 3 is a plan view and a side view for explaining an internal structure of an assembly (hereinafter abbreviated as HDA). 1 and 2, an HDA constituting a mechanical main body of a magnetic disk device according to the present invention includes a magnetic recording disk 1 for magnetically recording data, a spindle motor 2 for rotating the magnetic recording disk 1 at a constant speed, and a magnetic disk. Read data to recording disk 1
Magnetic head 3 for writing, supporting magnetic head 3,
A voice coil motor (hereinafter abbreviated as VCM) for rotatably driving the carriage 5, which is rotatable about the rotation axis of the pivot bearing 4, and positioning the magnetic head 3 on the magnetic recording disk 1 for reading / writing data. ) 6,
The FPC 7 for transferring the signal from the magnetic head 3 to the circuit section, the base 8 for mounting these, and the like are mainly configured. The carriage 5 includes a load spring 20 (FIG. 1) that supports the magnetic head 3, the head arm 10, and the bobbin 1.
3, the bobbin 13 and the plurality of head arms 10 are fixed to the rotary shaft 4 by screws 11 to form a carriage 5. The bobbin 13 fixes the coil 14 forming the voice coil motor, and is preferably made of a non-magnetic material such as plastic. A magnetic body 12 for retracting the magnetic head is provided on a part of the bobbin 13. Permanent magnets 15a and 15b are arranged on the surface facing the coil 14, that is, in the direction of the paper surface of FIG.
A magnetic circuit of the VCM 6 is configured with 16b (FIG. 2).

Here, the magnetic substance includes not only a ferromagnetic substance but also a diamagnetic substance. This is because it may be necessary to relax the restrictions on the magnetic material arrangement in order to downsize the disk device, even if it is somewhat expensive. Materials other than ferromagnetic materials and antiferromagnetic materials have a much smaller degree of magnetization,
More or less everyone has some magnetism. Of them
When an external magnetic field is applied, a positive magnetic charge appears in that direction and a negative magnetic charge appears on the opposite side is called a paramagnetic substance. On the contrary, the one in which the negative magnetic charge appears in the direction of the external magnetic field and the positive magnetic charge appears on the opposite side is called a diamagnetic material. Here, substances other than the ferromagnetic substance and the antiferromagnetic substance are called non-magnetic substances.

The main ferromagnetic materials, antiferromagnetic materials and permanent magnet materials are shown below. Ferromagnetic material: CoPt, cobalt ferrite (CoFe2
O4), CrO2, CrTe, aluminum Heusler alloy (Cu2MnAl), Fe3Al, Fe3C, Fe
Co, magnetite (Fe3O4), FeNi3, Mn
4N, Mn2Sb, nickel ferrite (NiFe2O
4), Ni3Mn, yttrium iron garnet (Y3F
e5O12) Antiferromagnetic material: CoO, Cr2O3, CrSb, Cr, α
Fe2O3, MnTe, NiO Permanent magnet material: carbon steel, tungsten steel, KS steel (above, quench hardening magnet), Alnico 5, Cunife
1 (above, precipitation hardened magnet), rare earth cobalt magnet (S
mCo5; magnetic field molding magnet), OP magnet (Co0.7)
5Fe2.25O4), Ferroxdure 2 (B
aFe12O19) (above, oxide magnet).

In this embodiment, the direction in which the force acts when the ferromagnetic material is used is explained, but it goes without saying that the direction of the force is reversed when the antiferromagnetic material is used. Yes. Further, a magnet may be used instead of the magnetic body, but in this case, the retract operation is not stable until the magnet loses its magnetic force before it can be regarded as a magnetic body due to the strong leakage magnetic flux of the VCM.

In the magnetic disk drive according to this embodiment, the permanent magnets 15a and 15b of the VCM 6 and the coil 14 are used.
Between the yoke 16b on the other side across the
Magnetic flux is generated between the M gaps in the vertical direction (axial direction of the rotating shaft 4) when seen in a plan view, and the magnetic flux density of this magnetic flux is shown by contour lines 501 (FIG. 3). The magnetic flux density contour line 501 is
It is on a concentric circle (more accurately, on a concentric trapezoid) almost along the outer shape of the permanent magnet 15a or 15b, and the magnetic flux density is substantially parallel to the outer edge of the permanent magnet and becomes higher toward the center of the magnetic flux density. . Here, when a magnetic body having a degree of freedom only in the plane direction (direction perpendicular to the rotation axis 4) is placed in this vicinity, the magnetic body is perpendicular to the magnetic flux density contour line (that is, the outer edge of the permanent magnet), that is, A force acts in the direction perpendicular to the axis of rotation, and the force is carried to the location with the highest magnetic flux density, that is, toward the center of the permanent magnet.

Based on the above, a further description will be given with reference to FIG. When the magnetic body 12 (FIG. 1) is placed at a position having one degree of freedom to rotate about the rotation axis 4a (FIG. 3) of the pivot bearing 4, the magnetic body 12 is perpendicular to the magnetic flux density contour line 501 (permanent). A force acts in the direction perpendicular to the outer edge 15b of the magnet. For example, the force Fb acts at the position of the magnetic body 12b, and a counterclockwise rotation moment Mb is generated with respect to the rotation shaft 4a of the pivot bearing 4. That is, the magnetic body 12b moves counterclockwise around the rotation shaft 4a of the pivot bearing 4. The force Fc also acts at the position of the magnetic body 12c, and the rotation shaft 4 of the pivot bearing 4
A counterclockwise rotation moment Mc is generated with respect to a, and the magnetic body 12c moves the rotation shaft 4a of the pivot bearing 4a.
Move counterclockwise around. However, the magnetic substance 12a
Although the force Fa is generated at the position of, the direction of the force Fa is toward the rotating shaft 4a of the pivot bearing 4 and therefore balances with the reaction force thereof, so that no rotating moment is generated. That is, the magnetic body 12a is fixed at that position. Further, the force Fd acts at the position of the magnetic body 12d, and the pivot bearing 4
Rotation moment Md about the rotation axis 4a of
Occurs. That is, the magnetic body 12d, conversely, moves clockwise around the rotary shaft 4a of the pivot bearing 4.

In general, during operation of the magnetic disk device, the magnetic head 3 (FIG. 2) reads / writes data while slightly floating in the data area of the magnetic recording disk 1. When the operation of the magnetic disk device stops, the magnetic head 3 comes into contact with the magnetic recording disk 1 and stops while sliding. Here, the magnetic head 3 needs to move regardless of the position where it comes into contact with the magnetic disk 1 and finally stop at the shipping area of the magnetic disk 1. Therefore, all magnetic heads 3 except the shipping area
If the magnetic body 12 is set at a position where a rotational moment in the shipping area (in this embodiment, the innermost circumferential position of the magnetic disk 1) is generated in the movable area of the magnetic head 3, the magnetic head 3 stops rotating the magnetic disk 1. You can always start the retract. Furthermore, after starting the retract, permanent magnet 1
5b (FIG. 3) and the magnetic body 12 are stationary at a position where forces acting on each other are balanced. This balanced position is the magnetic head 3
Is set in the shipping area of the magnetic disk 1 (in this embodiment, the innermost circumferential position of the magnetic disk 1), the magnetic head 3 can be stopped in the shipping area. Further, the magnetic body 12 is set at a position where a rotational moment in the shipping region direction is generated in all movable regions of the magnetic head 3 including the shipping region, and further a stopper (in this embodiment, the IN stopper 17b (FIG. 1)). Even when the magnetic head 3 is moved to the shipping area by stopping the bobbin 13 against the stopper, the magnetic head 3 can always be retracted when the rotation of the magnetic disk 1 is stopped.

In the present embodiment shown in FIG. 1, when the magnetic head 3 is at the innermost circumference, the magnetic body 12c is located at the position of the magnetic body 12c (FIG. 3), and when it is at the outermost circumference, it is located near the magnetic body 12b.
Is adhered and fixed to the bobbin 13. As described above, in the entire moving region of the magnetic head 3, a counterclockwise rotation moment is generated in the magnetic body 12 with respect to the rotation shaft 4a of the pivot bearing 4, and when the rotation of the magnetic disk 1 is stopped, the magnetic head 3 is It moves to the innermost shipping area of the magnetic disk 1. When the magnetic head 3 moves to the inner circumference side, the bobbin 13 of the carriage moves to the IN stopper 17b.
By hitting (Fig. 1), the magnetic head can be stably stopped at this position.

In this embodiment, the innermost peripheral position is the shipping region, but it goes without saying that the magnetic member 12 can be positioned near 12d and can be stopped near the outermost peripheral by using the OUT stopper 17a. Absent.

FIG. 4 is a diagram showing a second embodiment.
In FIG. 4, the carriage 105 is integrated with a head arm that supports the magnetic head 103 and a bobbin. Further, in the embodiment of FIG. 1, the magnetic body 112 further includes the permanent magnets 15a and 15b of the VCM 6 and the pivot bearing 4 of the pivot bearing 4. While it is located on the opposite side, in FIG. 4, it is located on the side of the pivot bearing 4a with respect to the VCM permanent magnets 115a and 115b. In FIG. 5, the magnetic material 112 is located at the position of the magnetic material 112a when the magnetic head 103 is at the outermost circumference, and at the position of the magnetic material 112b when it is at the center of the disk.
When it is located at the innermost circumference, it is located on the magnetic body 112c.
At each position, the magnetic body 112 exerts a force in the direction perpendicular to the magnetic flux density contour line 502 (FIG. 5) (direction perpendicular to the outer edge 115a of the VCM permanent magnet) Fa, Fb,
Fc is generated, and Fa, Fb, and Fc further generate component forces of counterclockwise rotation moments Ma, Mb, and Mc on the rotation shaft 104a of the pivot bearing,
The magnetic body 112b moves counterclockwise around the rotating shaft 4a of the pivot bearing. That is, the magnetic head 10
3 moves to the shipping area of the magnetic disk 101 in the entire movement area from the outermost circumference to the innermost circumference.

[0029]

As described above, in the magnetic disk device according to the present invention, the bobbin is made of a non-magnetic material and a magnetic material is provided on a part of the bobbin, so that the magnetic material of the hobbin leaks to the permanent magnet of the voice coil motor. It is attracted by the magnetic flux, and the magnetic force can move the magnetic head to a predetermined position.

Since the structure is simple and no dedicated magnet is used, the number of parts is small, the cost is low, and the reliability is high.

Since the magnetic body can be provided at the height position between the air gaps of the voice coil motor, the retract structure can be provided in a smaller installation space.

[Brief description of drawings]

FIG. 1 is a detailed view around a carriage according to the present exemplary embodiment.

2A and 2B are a plan view and a side view for explaining the internal structure of the HDA of the present embodiment.

FIG. 3 is an explanatory diagram of the principle of the present embodiment.

FIG. 4 is a detailed view around the carriage according to the present exemplary embodiment.

FIG. 5 is an explanatory view of the principle of the present embodiment.

[Explanation of symbols]

1, 101: magnetic disk, 3, 103: magnetic head, 4a, 104a: rotating shaft of pivot bearing, 5, 105: carriage 12, 12a, 1
2b, 12c, 12d, 112, 112a, 112b,
112c: magnetic material, 13: bobbin, 14, 114:
Coil, 15a, 15b, 115a, 115b: V
CM permanent magnet, 16, 116: VCM yoke

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Kenjiro Kai Kai 2880 Kokufu, Odawara, Kanagawa Stock Company Hitachi Storage Systems Division (72) Inventor Atsushi Ito 2880, Kozu, Odawara, Kanagawa Hitachi Storage Co., Ltd. System Division

Claims (5)

[Claims] 1. A magnetic recording disk for recording data, a magnetic head for recording / reproducing data on / from the magnetic recording disk, a carriage for supporting the magnetic head, and a coil fixed to the carriage. In a magnetic disk device having a permanent magnet arranged to face the coil and a yoke for fixing the permanent magnet, the permanent magnet is interacted with the permanent magnet in the vicinity of a coil attachment portion of the carriage to keep the carriage in a predetermined position. To the position,
A magnetic disk device comprising a magnetic body for stationary. 2. The magnetic disk device according to claim 1, wherein the permanent magnet has a plane in the vicinity of the magnetic body, the plane being perpendicular to the surface facing the coil, the perpendicular line passing through the plane, and the center of the magnetic body. A magnetic disk device, wherein a straight line connecting a position and a rotation axis of the carriage does not match within the entire moving area of the magnetic head, or matches at only one position. 3. The magnetic disk device according to claim 1 or 2, wherein a magnetic head is provided so as to face an inner peripheral direction of a magnetic recording disk when the magnetic disk is stopped. . 4. The magnetic disk device according to claim 3, wherein the center position of the magnetic body is a vertical line passing through a plane perpendicular to the surface of the permanent magnet facing the coil, and is approximately from the center position of the magnetic body. A vector directed toward the center of the permanent magnet is provided so as to have a negative rotation moment with respect to the rotation axis of the carriage, and the magnetic head is magnetized by negative rotation with respect to the rotation axis of the carriage. A magnetic disk device, which is provided so as to face an inner circumferential direction of a recording disk. 5. The magnetic disk device according to claim 3, wherein the center position of the magnetic body is a vertical line passing through a plane perpendicular to the surface of the permanent magnet facing the coil, and is approximately from the center position of the magnetic body. A vector directed toward the center of the permanent magnet is provided so as to have a positive rotation moment with respect to the rotation axis of the carriage, and the magnetic head is magnetized by positive rotation with respect to the rotation axis of the carriage. A magnetic disk device, which is provided so as to face an inner circumferential direction of a recording disk.