JP2848340B2 - Magnetic disk drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk drive for reading required data from a rotating magnetic disk surface and writing data on the magnetic disk surface by a magnetic head.

[0002]

2. Description of the Related Art Generally, this type of magnetic disk drive is
The magnetic head is mounted on a rotary type carriage, and the magnetic head is floated at a minute gap by air pressure generated as the magnetic disk rotates at a high speed, thereby reading and writing magnetic recording. The carriage of the magnetic disk drive reads a positioning pattern written on the magnetic disk by a head, and performs positioning by forming a servo loop.

The magnetic disk drive has been moving in the direction of improving the recording density. There are two methods for improving the recording density: a method of increasing the bit density of the track and a method of reducing the track width to reduce the track density. There is a way to raise. Recently, the track width has been reduced to about 10 μm or less.

As shown in FIG. 4, a spindle hub 4 on which a magnetic disk 1 is mounted is provided with a bearing 5 such as a bearing.
The rotating shaft 2 is rotatably supported by the disk rotating shaft 2 via a and 5b, and both ends of the rotating shaft 2 are fixedly supported by the substrate 3. On the other hand, a magnetic head 9 corresponding to the magnetic disk 1 is supported by an arm holder 12, and the arm holder 12 is connected to a head rotating shaft 13 via bearings 14a and 14b.
It is supported for rotation. The magnetic head 9 is rotated by a torque generated by the voice coil motor coil 21 supported by the arm holder 12 and a permanent magnet (not shown) facing the coil 21. The magnetic head 9 reads positioning information and reads / writes data. I do.

Usually, in a magnetic disk drive, as soon as a request for reading or writing information on a target track on the magnetic disk is made, the magnetic head 9 is rapidly moved in the radial direction of the magnetic disk 1 so as to minimize the access time. Position. A voice coil motor is usually used for this movement.

[0006]

However, when the voice coil motor operates rapidly according to a read / write command, a magnetic head positioning system (hereinafter referred to as a servo system).
In, the resonance frequency becomes a problem. If the resonance frequency is too low or the vibration level is too high, the servo system oscillates, making it impossible to accurately position the magnetic head. Conventionally, the recording density of a magnetic disk is low,
Although there was a sufficient margin for writing, with the recent increase in recording density and capacity and a reduction in seek time, the margin has been lost, and the above-mentioned vibration becomes a serious problem.

In particular, in the conventional magnetic disk drive, the coil for the voice coil motor is energized for positioning the magnetic head, and the coil is moved by using the magnetic flux of the opposed permanent magnet to generate a force. This serves as an excitation source, and the coil portion (including the coil and the portion of the arm holder that holds the coil) vibrates up and down. Generally, when the magnetic head simply vibrates up and down only, and has only a so-called in-plane component (a component displacing up and down) and no vibration component in the positioning direction (arm rotation direction), the effect is extremely large. Few.

The shape of the positioning mechanism, particularly the coil, is often asymmetric in consideration of hitting the stopper and reducing the weight. For this reason, the above-described vibration of the coil portion, especially the first bending mode, is not a simple vertical vibration,
It has a slightly twisted out-of-plane vibration component. As a result, the entire arm holder is twisted and a vibration component in the seek direction appears, and in some cases, the servo system oscillates.

[0009]

A magnetic disk drive according to the present invention includes a magnetic head facing a magnetic disk, a suspension for holding the magnetic head, and an arm holder for supporting the suspension and a coil for a voice coil motor. The arm holder is rotatably supported by a head rotating shaft via a bearing, and the rotating shaft is substantially perpendicular to a straight line connecting the magnetic head and the head rotating shaft in the magnetic disk device supported by the substrate; The arm holder has a groove or a plurality of counterbore holes or through holes.

[0010]

Next, the present invention will be described with reference to the drawings. 1 and 2 show a first and a second embodiment of the present invention.

In FIG. 1, a spindle hub 4 on which a magnetic disk 1 is mounted is rotatably supported on a disk rotating shaft 2 via bearings 5a and 5b, and both ends of the rotating shaft 2 are fixedly supported on a substrate 3. Have been. On the other hand, the magnetic disk 1
Is supported by an arm holder 12, and the arm holder 12 is rotatably supported by a head rotating shaft 13 via bearings 14a and 14b. A coil 21 for a voice coil motor is adhered to the arm holder 12, and the magnetic head 9 is driven to rotate at a high speed by a torque generated by an opposing permanent magnet (not shown).

At this time, as described above, when a driving force is applied to the coil portion 15 (including the voice coil motor coil 21 and the arm holder portion holding the coil portion), it becomes a vibration source and becomes a coil portion. Reference numeral 15 vibrates greatly at the resonance point.
On the other hand, in order to obtain an efficient driving force, a gap (not shown) that generates a magnetic flux of a permanent magnet into which a coil is inserted is provided.
It is made as narrow as possible to increase its magnetic flux density.
For this reason, the coil part 15 usually has a relatively small thickness. For example, the thickness of the coil 15 for a 3.5 "magnetic disk drive is 1.5 to 2.5 mm.

Although it depends on the material of the coil and the arm holder for holding the coil, the coil portion 15 vibrates largely up and down like a fan because of its relatively small thickness.
However, a groove is cut in the arm holder 12 in a direction (seek direction) substantially perpendicular to a straight line connecting the magnetic head 9 and the rotating shaft 13 (FIG. 1A is a cross-sectional view taken along AA of the groove). 1 (b)), since the rigidity of the coil portion 15 decreases along the groove, the vertical vibration of the coil portion 15 exhibits a simple fan-shaped bending mode in which the coil portion 15 bends along the groove.

That is, when the coil portion of the arm holder 12 has an asymmetric shape as described above, the coil portion 15 exhibits not a simple vertical vibration but a slightly inclined or twisted vibration mode. Although the head has a component in the seek direction, in the present invention, even if the arm holder 12 has an asymmetric shape in the groove, the coil portion 15 shows a simple bending mode along the groove, so that vibration in the seek direction Only vertical vibration components having no component (out-of-plane vibration components), so-called in-plane displacement.

As a result, the entire arm holder 12 is not tilted or twisted, so that almost no vibration component in the seek direction appears. As a result, the servo system does not oscillate, and an extremely stable positioning operation can be obtained. .

Similarly, in FIG.
2 includes a plurality of counterbore holes 19 (a cross-sectional view at BB is shown in FIG. 3C) in a direction substantially perpendicular (seek direction) to a straight line connecting the magnetic head 9 and the head rotation shaft 13 or a through hole. Since the hole 19 ((a cross-sectional view at BB is shown in FIG. 3B) is formed), even if the arm holder 12 has an asymmetric shape, the coil portion 15 has low rigidity along the row of holes. Therefore, a simple bending mode is shown, that is, as described above, since there is no out-of-plane vibration component due to only in-plane displacement, the servo system does not oscillate and an extremely stable positioning operation can be obtained.

In the case where the shape of the coil portion of the arm holder 12 is asymmetric, for the same reason as described above, a groove or a plurality of grooves are formed in a direction substantially perpendicular to the straight line connecting the magnetic head 9 and the rotating shaft 13. By providing a row of individual counterbore holes or through holes 19, vibration in the positioning direction can be prevented only by in-plane displacement.

FIG. 3 shows a case where the shape of the arm portion 10 of the arm holder 12 for supporting the magnetic head 9 is asymmetric. When the arm portion 10 simply vibrates up and down as described above, There is no problem with positioning accuracy,
In the case of a slightly twisted vertical vibration due to the asymmetric shape, that is, in the case of having an out-of-plane vibration component, the positioning accuracy is deteriorated. However, the arm portion 10 of the arm that supports the magnetic head 9 has a groove (FIG. 3) that is substantially perpendicular (seek direction) to a straight line connecting the magnetic head 9 and the rotating shaft 13.
(A) is a cross-sectional view at CC shown in FIG. 3 (b)), or a plurality of rows of counterbore holes or through holes 19 are provided, so that the arm portion 10 is arranged along the groove or the row of holes. Even if the arm portion 10 is asymmetrical, only the in-plane component is vibrated, and there is no vibration in the positioning direction. Therefore, stable servo characteristics can be obtained.

[0019]

As described above, according to the present invention, the arm holder is provided with a groove or a plurality of through holes in a direction substantially perpendicular (seek direction) to a straight line connecting the magnetic head and the rotation axis. With this configuration, vibration of the resonance frequency of the servo system in the positioning mechanism of the magnetic disk device is less likely to appear, control of the servo system is facilitated, and reliable and stable positioning can be performed.

[Brief description of the drawings]

FIG. 1A is a plan view of a magnetic disk drive showing a first embodiment of the present invention. FIG. 1B is a cross-sectional view of the groove of the coil portion at AA.

FIG. 2A is a plan view of a magnetic disk drive according to a second embodiment of the present invention. FIG. 2B is a cross-sectional view taken along BB of the through hole of the coil portion. FIG. 2C is a cross-sectional view of the counterbore hole of the coil portion at BB.

FIG. 3 is a plan view of a magnetic disk drive showing a third embodiment of the present invention. FIG. 3B is a cross-sectional view of the groove of the arm portion.

FIG. 4 is a plan view showing a conventional magnetic disk drive.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnetic disk 2 Disk rotating shaft 3 Substrate 4 Spindle hub 5a, 5b Bearing 9 Magnetic head 10 Arm part 12 Arm holder 13 Head rotating shaft 14a, 14b Bearing 15 Coil part 18 Groove 19 Counterbore or through hole 21 Voice coil motor Coil

Claims (6)

(57) [Claims] 1. A magnetic head facing a magnetic disk, a suspension holding the magnetic head, and an arm holder supporting the suspension and a coil for a voice coil motor, wherein the arm holder rotates a head via a bearing. A magnetic disk device rotatably supported by a shaft, wherein the rotation shaft is supported by a substrate , wherein a groove is provided in the arm holder in a direction substantially perpendicular to a straight line connecting the magnetic head and the head rotation shaft; Provided from one end to the other end of the arm holder;
Magnetic disk apparatus characterized by being. 2. A magnetic head opposed to a magnetic disk, a suspension holding the magnetic head, and an arm holder supporting the suspension and a coil for a voice coil motor, wherein the arm holder rotates a head via a bearing. A magnetic disk drive rotatably supported by a shaft, wherein the rotation shaft is supported by a substrate; a plurality of counterbore holes or A through hole is provided , and the plurality of counterbore holes or through holes are substantially
One end to the other end of the arm holder at a plurality of symmetric positions
A magnetic disk drive, wherein the magnetic disk drive is arranged in a row . 3. A magnetic head facing a magnetic disk, a suspension holding the magnetic head, and an arm holder supporting the suspension and the coil for the voice coil motor, wherein the arm holder is a head via a bearing. A magnetic disk drive rotatably supported by a rotating shaft, wherein the rotating shaft is supported by a substrate; and a coil for a voice coil motor in the arm holder, substantially perpendicular to a straight line connecting the magnetic head and the head rotating shaft. a groove in the coil portion is a portion that supports provided, the shape of the groove magnetic disk apparatus which is a substantially symmetrical about the straight line. 4. A magnetic head opposed to a magnetic disk, a suspension holding the magnetic head, and an arm holder supporting the suspension and a coil for a voice coil motor, wherein the arm holder rotates a head via a bearing. A magnetic disk device rotatably supported by a shaft, wherein the rotation shaft is supported by a substrate, wherein a coil for a voice coil motor of the arm holder is provided in a direction substantially perpendicular to a straight line connecting the magnetic head and the head rotation shaft. a plurality of countersunk holes or through holes provided in the coil portion is a portion that supports, substantially the plurality of countersunk holes or through holes relates to the aforementioned straight line
A magnetic disk drive characterized by being arranged at a plurality of symmetrical positions . 5. A magnetic head opposed to a magnetic disk, a suspension holding the magnetic head, and an arm holder supporting the suspension and a coil for a voice coil motor, wherein the arm holder rotates a head via a bearing. A magnetic disk device rotatably supported by a shaft, wherein the rotation shaft is supported by a substrate, wherein the magnetic head of the arm holder is supported in a direction substantially perpendicular to a straight line connecting the magnetic head and the head rotation shaft. a groove provided in the arm portion, said groove provided from one end to the other end of the arm portion
Magnetic disk apparatus characterized by that. 6. A magnetic head facing a magnetic disk, a suspension holding the magnetic head, and an arm holder supporting the suspension and a coil for a voice coil motor, wherein the arm holder rotates a head via a bearing. A magnetic disk device rotatably supported by a shaft, wherein the rotation shaft is supported by a substrate, wherein the magnetic head of the arm holder is supported in a direction substantially perpendicular to a straight line connecting the magnetic head and the head rotation shaft. A plurality of counterbore holes or through holes are provided in the arm portion, and the plurality of counterbore holes or through holes are substantially
A magnetic disk drive provided at a plurality of symmetrical positions .