JP2003051167A - Magnetic disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic disk device for achieving a positioning structure suited to miniaturization and thinning of the device, and setting of large-capacity high recording density and a high information processing speed. SOLUTION: A member having natural frequency equal to that of the head is provided in a surface opposite a head arm on which one head is mounted. For the member having the natural frequency equal to that of the head, its outermost shape opposite a disk (profile projected in a direction vertical to a magnetic disk surface) is formed in a shape equal to or not projected from the head. Additionally, the member having the natural frequency equal to that of the head is provided in the head arm by the same means as that for the head.

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, which is one of storage devices for computers, and more particularly to downsizing and thinning of the magnetic disk device, large capacity and high recording density, and high speed information processing. The present invention relates to a magnetic disk device having a positioning structure suitable for use in a computer.

[0002]

2. Description of the Related Art Conventionally, as a positioning mechanism for achieving downsizing and thinning of a device, large capacity and high recording density, and high speed of information processing, Japanese Unexamined Patent Publication No. 8-45205 (hereinafter referred to as "first") is known. Conventional example) and JP-A-5-325.
There is an example described in Japanese Patent No. 459 (hereinafter referred to as a second conventional example). The above-mentioned first and second conventional techniques suppress the vibration generated in the magnetic disk device and improve the positioning accuracy.

That is, in the first conventional example, by fixing the voice coil motor and the base via a viscoelastic member or the like, it is possible to suppress the vibration of the voice coil motor generated by the movement of the carriage from being transmitted to the base. To do.

In the second conventional example, a vibration absorbing material is provided on the spring arm to suppress residual vibration due to the spring arm at the time of seeking.

[0005]

The magnetic disk drive is
For example, it is mounted inside a notebook-type personal computer, and has been required to be small and thin and have a large capacity and a high recording density. In addition to the power supply from the outside, such notebook type personal computers are mainly the type that has an internal battery and can be used without a nearby electrical outlet. Is also required. In addition to the above, it goes without saying that there is a demand for device reliability, low cost, and high information processing speed.

From the above requirements, as a positioning mechanism of a magnetic disk device, it is necessary to minimize the relative positional deviation between the disk and the head. The factors include vibration of the head and the carriage swinging part that supports the head, and vibration of the disk and the spindle motor rotating part that supports the disk.

When the head reads the information recorded in a circular shape on the disk surface, if the width of the vibration is large, the information adjacent to the target position in the radial direction is affected. Must be large. This will not increase the capacity. In addition, there are problems in downsizing and thinning.

Further, since the vibration of the head increases the number of times the head position is repeatedly corrected in the positioning control, and it takes time until the head is accurately positioned at the target position. Therefore, the information processing speed of the magnetic disk drive is increased. I have a problem.

Further, conventionally, in order to use the entire surface of the mounted disk, the head arm of the carriage is
As shown in FIG. 6, a portion where two heads are mounted, and FIG.
There is a part where one head is mounted as shown in FIG. There is a problem that vibration (amplitude) is larger in a portion where one head is mounted than in a portion where two heads are mounted.

As a method for solving these problems, methods such as those in the first conventional example and the second conventional example have been studied. However, the vibration (amplitude) of the portion in which one head is mounted is reduced. It was not enough to hold back.

The present invention has been made in view of the above-mentioned problems of the prior art, and suppresses the vibration (amplitude) of the portion in which one head is mounted, thus reducing the size and thickness of the apparatus and increasing the capacity and capacity. It is an object of the present invention to provide a magnetic disk device equipped with a positioning mechanism suitable for increasing the recording density and increasing the information processing speed.

[0012]

A first magnetic disk device of the present invention is a magnetic disk for recording information, a spindle motor for holding and rotating the magnetic disk, and a slider for recording / reproducing information on / from the magnetic disk. A head composed of a gimbal with a head arm part for fixing the head,
The present invention is applied to a magnetic disk drive including a carriage for moving and positioning a head in a radial direction on a disk surface, and a head disk assembly having a base and a cover for holding these and shielding them from the outside air. It has the following characteristics.

That is, a member having a natural frequency equivalent to that of the head in a mounted state is provided on the surface opposite to the head arm on which one head is mounted.

The second magnetic disk drive of the present invention has the following features. That is, in the first aspect of the present invention, the profile of the member projected in the direction perpendicular to the magnetic disk surface has the same shape as the profile of the head projected in the direction perpendicular to the magnetic disk surface, or Alternatively, it is characterized in that it does not protrude from the profile of the head projected in the direction perpendicular to the magnetic disk surface.

The third magnetic disk device of the present invention has the following features. That is, the member is provided on the head arm by the same means as the head.

A member may be provided on the surface opposite to the head arm having one head mounted thereon so as to generate a frequency equal to that of an arm having two heads mounted thereon. Further, the second invention and the third invention are applied to a member provided on the opposite surface of the head arm having one head mounted thereon so as to generate the same frequency as the arm having two heads mounted thereon. You may.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail with reference to the embodiments shown in the accompanying drawings.

1 to 3 are partial sectional views showing the basic structure of an embodiment of a magnetic disk device of the present invention.
The magnetic disk device is shown in three parts. FIG. 4 is a top view (cover open state) showing the basic structure (equivalent to FIGS. 1 to 3) of one embodiment of the magnetic disk device. In the following description, the head means the gimbal portion on which the slider is mounted.

In the basic structure of the magnetic disk device shown in FIGS. 1 to 3, the disk 5 for holding information magnetically having a magnetic film formed on the surface of aluminum or glass as a substrate material is formed by a spindle motor. It is driven to rotate. The spindle motor is configured as follows.
That is, the motor shaft 6f made of stainless steel
There is a hub 6a made of aluminum that rotates with high precision through the motor bearings 6b press-fitted in the upper and lower sides, and the hub 6a is preloaded by a spring (not shown) in the axial direction. The motor coil 6c fixed between the motor bearings 6b of the motor shaft 6f and the motor magnet 6d which is a permanent magnet are fixed to the inner surface of the hub 6a opposed to the motor coil 6c, and the motor coil 6c is energized to supply the hub 6a.
To rotate. Insert the disc 5 into the hub 6a, and use the ring-shaped clamp ring 4 made of aluminum, stainless steel or iron,
Is fastened to the hub 6a. The clamp ring 4 is fastened by shrink fitting the hub 6a. Alternatively, the upper surface of the hub 6a may be fastened with screws.

On the surface of the rotating disk 5,
Mainly formed by a ferrite or metal thin film provided with an electromagnetic coil for levitating while maintaining a constant space of 0.1 micron or less and converting between an electric signal and a magnetic field for magnetically writing or reading information. There is a head 16 made of the above material, and a carriage 3 made of aluminum or magnesium for accurately positioning the head 16 on the surface of the disk 5, which are wound with an aluminum wire or a copper wire having an insulating film. It is driven and positioned by a voice coil motor 2 which is composed of a linear coil 9, a permanent magnet 2a, and a yoke 2b for supporting the magnet 2a and forming a magnetic circuit. One of the yokes 2b has a magnet 2a having a south pole with respect to the coil 9 and a magnet 2 having a north pole with respect to the coil 9.
There are two types of a. These are fixed along the arc of the coil 9 moving in the left-right direction from the center of the moving angle of the coil 9 when the head 16 moves to write or read information on the surface of the disk 5. The magnet 2a is fixed to the other yoke 2b at a target position by sandwiching the position of the magnet 2a and the coil 9 and the polarity of the magnet 2a is opposite to the polarity of the magnet 2a which faces the magnet 2a with the coil 9 interposed. It has become. As a result, the carriage 3 is driven and positioned by flowing it through the coils 9 wound in the same direction between the magnets 2a while controlling the electric energy and the current direction.

Here, a new point different from the conventional magnetic disk device is that the head arms 3a of the uppermost and lowermost disks 5 among the plurality of disks 5 in FIG.
The head 16 is mounted on the first surface, and the second surface (first
(The surface opposite to the surface) is mounted with the dummy suspension 1.

In mounting, the voice coil motor 2 counter yoke 2c is removed, the coil 9 portion of the carriage 3 is inserted between the magnets 2a of the voice coil motor 2, and then the counter yoke 2c is connected to the yokes 2b. And then fastened to the yoke 2b with a screw. A signal at the time of reading / writing of the head 16 passes through a head arm 3a supporting the head 16 of the carriage 3 (not shown) by a thin wire of an electromagnetic coil provided in the head 16, and an FPC (flexible printed circuit board) 14 ( (See FIG. 4) is transmitted to the read / write control board 12 that controls signals when reading / writing the head 16 and is further bonded to the base 7 made of aluminum, stainless steel or iron located on the lower surface of the read / write control board 12. By the sealed connector 10 provided by
It is transmitted to the outside of the head disk assembly (hereinafter referred to as HDA). The hermetically-sealed connector 10 relays electrical signals between the inside and outside of the HDA, and hermetically seals a plurality of pins for transmitting signals and a molded portion for holding the pins. . The electric current of the coil 9 also passes through the FPC 14 and the sealed connector 1
It is transmitted to 0.

The hermetically sealed connector 10 is transmitted to a circuit board 11 for controlling a device provided outside the HDA. The drive current of the spindle motor 6 is transmitted from below the motor shaft 6f to the circuit board 11 by a cable and a connector (not shown). Coil 9 in case of abnormality
A stopper 19 is provided in order to prevent the head 3 from damaging the disk 5 or dropping the head 16 from the surface of the disk 5 due to a current more than the specified value flowing and the carriage 3 running away. Also, the head 16
There is an operation of recording information for detecting a position on the disk 5 by the head 16 of the apparatus on the disk 5 at the time of manufacturing, and a current of about 0.1 A is applied to the coil 9 to cause the carriage 3 to move to the stopper 19. Since it starts recording information from the pressed state, it also has a role of positioning. The motor shaft 6f, the rotation center axis of the carriage 3, and the voice coil motor 2 are fixed to the base 7, and a cover 8 made of aluminum, stainless steel or iron is screwed to the base.
The motor 7, the motor shaft 6f, the rotation center axis of the carriage 3, and the voice coil motor 2 are fixed. The vicinity of the screw hole provided in the cover 8 is recessed so that the screw head does not protrude from the upper surface of the cover 8 after fastening. In order to seal the inside of the HDA from the outside air, an aluminum seal having a thickness that does not allow moisture to pass through is used as a material on the mating surface of the base 7 and the cover 8 and a sealing seal 17 having an adhesive applied to one surface thereof is attached. (See FIGS. 1 to 3).

The HDA configured as described above accurately processes the signal in the operation state of writing or reading information between the head 16 and the disk 5.
Since inclusions must not enter this space and interfere with the magnetic field, it must be kept clean at all times. Therefore, an internal filter 13 (see FIG. 4) is provided, and air inside the HDA generated by rotation of the disk 5 is provided. The internal dust is captured by circulation.

Further, an air conditioner 15 is installed for controlling the humidity inside the HDA and adsorbing gas so that the humidity inside the HDA is always set within a fixed range and the contact resistance between the head 16 and the disk 5 is increased. By adsorbing a gas that adversely affects the device, the reliability of the device is improved. The large-capacity magnetic disk device is equipped with a plurality of disks 5 in order to obtain a storage capacity, and heads 16 are provided on the surfaces of the disks 5, respectively. A head 18 (see FIGS. 1 to 3) is provided, and the distance between the heads 16 is kept constant by accurately finishing the head 16 mounting surface of the carriage 3.

Next, the magnetic disk device shown in FIGS. 1 to 4 is different from the prior art, that is, the first and second head arms 3a of the uppermost and lowermost disks 5 of the plurality of disks 5 are different. The head 16 is mounted on the surface of
The point where the dummy suspension 1 is mounted on the second surface (the surface opposite to the first surface) will be described in detail.

FIG. 5 is a view showing a head arm 3a having a dummy suspension 1 mounted on one surface and a head 16 (gimbal portion mounted with a slider) mounted (one) on the opposite surface. FIG. 6 is a diagram (prior art) showing a head arm 3a having two heads 16 mounted therein. Further, FIG. 7 shows a head arm 3 having one head 16 mounted thereon.
It is the figure (a in the prior art) which showed a.

The head arm 3a having one head 16 shown in FIG. 7 has a large amplitude because there is no member for canceling the vibration of the head 16. On the other hand, as shown in FIG. 5, by mounting the dummy suspension 1 on the opposite surface of the head arm 3a (FIG. 5) on which one head 16 is mounted (FIG. 3), the vibration of the head 16 is reduced. The dummy suspension 1 can be offset, and the amplitude of the carriage 3 can be reduced.

The dummy suspension 1 is mounted on the head arm 3a, and the weight balance is taken into consideration by the shape and the plate thickness so that the same frequency as the head 16 is generated. In the embodiment, stainless steel is used as the material, and the head 16 has a shape with the same natural frequency as that of the head 16 and is formed by press working. This is fixed to the head arm 3a by a swedge which is the same means as the head 16 (see FIG.
reference).

Regarding the shape of the dummy suspension 1, the swing of the carriage 3 causes the dummy suspension 1 to come into contact with the base 7, the clamp ring 4 or the hub 6a, thereby narrowing the range in which the head 16 moves on the disk 5. Therefore, in the embodiment, the outer shape (profile projected in the direction perpendicular to the magnetic disk surface) facing the disk 5 is equivalent to the head 16 or is set to a shape that does not protrude from the head 16. There is.

Further, the thickness in the direction perpendicular to the surface of the disk 5 should be as thin as possible. In the embodiment, the plate is made of stainless steel, and a gap is secured to the extent that the tip of the dummy suspension 1 on the non-fixed side does not come into contact with the cover 8 or the base 7 with respect to the allowable impact value of the device. The dummy suspension 1 of the embodiment has a plate thickness of 0.12.
mm, and the tip is deflected by 0.13 mm when the device has a non-operating shock allowable value of 50G.

FIG. 8 shows a magnetic disk device according to an embodiment of the present invention (a device having a head arm 3a on which the dummy suspension 1 and one head 16 are mounted for the uppermost and lowermost disks 5). 6 is a graph showing the vibration characteristics (see FIG. 5), in which the horizontal axis is frequency and the vertical axis is displacement / excitation current = displacement / acceleration. Since the transfer function looks at the transfer rate of displacement / acceleration, the ideal transfer rate is a straight line 80 of −40 dB / decade as shown in the figure. However, since an actual magnetic disk device has a resonance point, the waveform rises above the straight line 80. Therefore, the size of the resonance point is represented with the line of the straight line 80 as the reference (0).

FIG. 9 is a graph showing the vibration characteristic of the magnetic disk device having the head arm 3a (see FIG. 5) on which the conventional single head 16 is mounted.

In FIG. 9, the frequency 5.3 represented on the horizontal axis.
A peak of about 32 dB (with the straight line 80 as the reference (0)) is seen near KHz. It has been found that the frequency of 5.3 KHz is a peak due to the vibration of the head arm 3a carrying one head 16. On the contrary,
In FIG. 8, the value near the frequency of 5.3 KHz shown on the horizontal axis is 22.
It is about dB (the straight line 80 is the reference (0)), the peak is significantly reduced as compared with the conventional technique, and a remarkable effect is seen.

As described above, one head 16 shown in FIG.
Since the vibration peak value of the carriage 3 can be significantly reduced as compared with a device having a head arm 3a equipped with a head arm 3a, the time required for the head 16 to accurately position at a target position can be shortened, and the information processing speed of the magnetic disk device can be reduced. The speed of can be improved. Further, since the space between adjacent information on the disk 5 can be narrowed, a large capacity and high recording density of the magnetic disk device can be achieved.

The dummy suspension 1 has a plate thickness of 0.
It is 12 mm, which is suitable for downsizing and thinning of the device.

[0037]

According to the present invention, the vibration (amplitude) of the head arm in the portion where one head is mounted is suppressed, and the size and thickness of the apparatus are reduced, the recording capacity is increased, and the information processing speed is increased. It is possible to provide a magnetic disk device provided with a positioning mechanism suitable for speeding up.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a left end portion obtained by dividing a basic structure of an embodiment of a magnetic disk device of the present invention into three parts.

FIG. 2 is a partial cross-sectional view of a central portion obtained by dividing the basic structure of one embodiment of the magnetic disk device of the present invention into three parts.

FIG. 3 is a partial sectional view of a right end portion obtained by dividing the basic structure of one embodiment of the magnetic disk device of the present invention into three parts.

FIG. 4 is a top view (cover open state) showing a basic structure (see FIGS. 1 to 3) of an embodiment of a magnetic disk device.

FIG. 5 is a diagram showing a head arm having a dummy suspension mounted on one surface and a head mounted (one) on the opposite surface.

FIG. 6 is a diagram showing a head arm on which two heads are mounted.

FIG. 7 is a diagram showing a head arm on which one head is mounted.

FIG. 8 shows vibration characteristics of a magnetic disk device (see FIG. 5) having a head arm 3a on which the dummy suspension 1 and one head 16 are mounted for the uppermost and lowermost disks 5. The graph.

FIG. 9 is a graph showing vibration characteristics of a magnetic disk device having a head arm (see FIG. 5) on which one conventional head is mounted. The graph showing the vibration characteristic of an example.

[Explanation of symbols]

1: Dummy suspension, 2: Voice coil motor,
2a: magnet, 2b: yoke, 2c: counter yoke, 3: carriage, 3a: head arm, 4: clamp ring, 5: disk, 6: spindle motor, 6
a: hub, 6b: motor bearing, 6c: motor coil, 6d: motor magnet, 6f: motor shaft, 7: base, 8: cover, 9: coil, 10: sealed connector, 11: circuit board, 12: lead Light control board, 1
3: internal filter, 14: FPC, 15: air conditioner, 1
6: head, 17: hermetic seal, 18: disk spacer, 19: stopper.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Mitsuru Imai             2880 Kozu, Odawara City, Kanagawa Stock Association             Storage Systems Division, Hitachi, Ltd. (72) Inventor Masayuki Motochi             2880 Kozu, Odawara City, Kanagawa Stock Association             Storage Systems Division, Hitachi, Ltd. (72) Hideyuki Takagi             2880 Kozu, Odawara City, Kanagawa Stock Association             Storage Systems Division, Hitachi, Ltd. F-term (reference) 5D059 AA01 BA01 CA08 CA25 CA26                       DA26 EA08 EA12                 5D088 JJ01

Claims (4)

[Claims] 1. A base and a cover, a magnetic disk whose surface facing the base or a surface facing the cover is a recording surface for recording information, and a spindle motor fixed to the base and rotating the magnetic disk. A first suspension that supports a slider on which a head that records and reproduces information on and from the recording surface is mounted; and a second suspension that has a natural frequency substantially equal to the natural frequency of the first suspension. Fixed to the base, and swinging the head arm,
And a carriage for moving and positioning the head in the radial direction of the magnetic disk, wherein the head arm is located on both the base side and the cover side of the magnetic disk. 2. A magnetic disk having recording surfaces for recording information on both sides (a first recording surface and a second recording surface), a spindle motor for rotating the magnetic disk, and a magnetic disk for the first recording surface. A first suspension supporting a slider on which a head for recording and reproducing information is mounted, and a second suspension having a natural frequency substantially equal to the natural frequency of the first suspension. No. 1 head arm, a third suspension supporting a slider on which a head for recording / reproducing information with respect to the second recording surface is mounted, and the natural frequency of the third suspension is substantially equal to that of the third suspension. A second head arm having a fourth suspension having a natural frequency; and swinging the first and second head arms to move the head to the magnetic field. A magnetic disk drive comprising: a carriage that moves and positions in the radial direction of the air disk. 3. The magnetic disk drive according to claim 1, wherein the second and fourth suspensions are dummy suspensions that support a head and a slider that are not used for recording / reproducing information. 4. The magnetic disk device according to claim 1, wherein the second and fourth suspensions are members that do not support the head and the slider.