JP3688445B2 - Magnetic disk unit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a magnetic disk device, and more particularly to a magnetic disk device used for a portable computer such as a laptop computer or a book computer.
[0002]
[Prior art]
In general, in a small portable computer such as a personal computer, a laptop computer, or a book computer, a magnetic disk device is used as a memory for storing a large amount of information. In order to improve portability, this type of computer has been further reduced in size and improved in processing capacity. Accordingly, the magnetic disk device is also required to be reduced in size and increased in capacity.
[0003]
A magnetic disk device usually includes a spindle motor that rotationally drives a magnetic disk as a recording medium, a magnetic head that records and reproduces on the magnetic disk, and a carriage assembly that supports the magnetic head so as to be movable with respect to the magnetic disk. And a voice coil motor (hereinafter referred to as VCM) for driving and positioning the magnetic head on a desired track of the magnetic disk by driving the carriage assembly.
[0004]
The VCM includes a pair of yokes opposed at a predetermined interval, a magnet disposed between the yokes, a voice coil attached to the carriage assembly side and disposed between the yokes so as to face the magnets, It has.
Usually, when increasing the storage capacity of a magnetic disk device having the above-described configuration, a method of increasing the number of mounted magnetic disks is employed.
[0005]
[Problems to be solved by the invention]
However, when the number of mounted magnetic disks is increased in order to increase the storage capacity, there is a problem that the magnetic disk device becomes large, particularly thick. That is, as the number of magnetic disks increases, the number of magnetic heads increases accordingly, and the inertia of the carriage assembly increases. Therefore, it is necessary to increase the driving force of the VCM that drives the carriage assembly. In order to increase the driving force of the VCM, it is necessary to increase the magnetic force by increasing the size of the magnet. Accordingly, the distance between the pair of yokes increases accordingly, and the thickness of the entire magnetic disk device increases.
[0006]
The present invention has been made in view of the above points, and an object thereof is to provide a magnetic disk device capable of increasing the storage capacity without increasing the size of the device, particularly without increasing the thickness. It is in.
[0007]
[Means for Solving the Problems]
To achieve the above object, a magnetic disk device according to the present invention comprises a magnetic disk, a spindle motor that holds and rotates the magnetic disk, a magnetic head that records and reproduces information on the magnetic disk, and A carriage assembly that movably supports the magnetic head with respect to the magnetic disk, a voice coil motor that moves the carriage assembly to position the magnetic head at an arbitrary position on the magnetic disk, and is opposed to the magnetic disk A case housing the magnetic disk, spindle motor, carriage assembly, and voice coil motor, a mounting surface on which a plurality of electronic components are mounted, and an electronic component that is opposed to the mounting surface. Has a non-mounting surface where the mounting surface is not mounted. Opposite the external surface of the bottom wall of the casing and a printed circuit board fixed to the case,
The voice coil motor includes a pair of yokes opposed to each other at intervals, a magnet fixed to at least one of the yokes and disposed between the pair of yokes, and attached to the carriage assembly and the pair of yokes. And a voice coil provided opposite to the magnet between the yokes. One of the yokes is provided in a state where at least a part of the yoke is embedded in the bottom wall of the case, and the printed circuit board is notched at a portion facing the bottom wall portion in which the one yoke is embedded. In addition, the outer surface of the bottom wall portion in which the one yoke is embedded and the non-mounting surface are provided in substantially the same plane .
[0008]
According to the magnetic disk apparatus of the present invention, the bottom wall has an opening, and the one yoke is embedded in the opening and exposed to the outer surface of the bottom wall.
[0009]
As described above, by providing at least part of one yoke embedded in the bottom wall of the case, it is necessary to increase the thickness of the case even when the magnet of the voice coil motor is increased to increase the driving force. Disappear. This makes it possible to increase the number of magnetic disks mounted and increase the recording capacity without increasing the size of the magnetic disk device.
[0010]
The magnetic disk apparatus according to the present invention further includes a printed circuit board provided to face the outer surface of the bottom wall of the case, and the printed circuit board has a notch facing the bottom wall portion in which the yoke of the case is embedded. have. That is, the printed circuit board is provided avoiding the bottom wall portion.
[0011]
According to such a configuration, the printed circuit board can be provided in close contact with the outer surface of the bottom wall of the case, and an increase in the thickness of the entire apparatus including the printed circuit board can be suppressed.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment in which a magnetic disk device of the present invention is applied to a hard disk drive (hereinafter referred to as HDD) will be described in detail below with reference to the drawings. As shown in FIGS. 1 and 2, the HDD includes a case 10. The case 10 is screwed to the main body by a rectangular box shape having an open upper end, that is, a main body 12 having a rectangular bottom wall 12a and four side walls erected on the side edges of the bottom wall, and a plurality of screws 11. And a top cover 14 that closes the upper end opening of the main body.
[0013]
In the case body 12, there are two magnetic disks 16a and 16b as magnetic recording media, a spindle motor 18 for supporting and rotating these magnetic disks, and a magnetic head for recording and reproducing information on the magnetic disks. A plurality of magnetic head assemblies 20 provided, a carriage assembly 22 rotatably supporting these magnetic head assemblies, a voice coil motor 24 for rotating and positioning the carriage assembly, a substrate unit 21 having a preamplifier and the like are housed. ing.
[0014]
A printed circuit board 19 that controls the operation of the spindle motor 18, the voice coil motor 24, and the magnetic head assembly 20 is screwed to the outer surface of the main body 12, and is positioned facing the bottom wall 12a of the main body. .
[0015]
The spindle motor 18 includes a bracket 27, a pivot 28 having a lower end fixed to the bracket and standing in the case body 12, and a cylindrical hub rotatably supported on the pivot via a pair of ball bearings. 30. The bracket 27 constituting the lower part of the motor is fitted into an opening 26 formed in the bottom wall 12a of the case body 12, protrudes slightly from the outer surface of the bottom wall 12a, and is screwed to the bottom wall 12a. . The bracket 27 may be formed integrally with the bottom wall 12a of the case.
[0016]
The two magnetic disks 16a and 16bc are coaxially fitted to the outer peripheral surface of the hub 30 of the spindle motor 25 and are stacked along the axial direction of the hub. A spacer ring 32 fitted to the hub 30 is interposed between two adjacent magnetic disks. The magnetic disks 16 a and 16 b and the spacer ring 32 are fixed to the hub 32 by a disk-shaped clamper 34 screwed to the upper end of the hub 30. These magnetic disks 16a and 16b are rotationally driven by a spindle motor 25 at a predetermined speed.
[0017]
The carriage assembly 22 includes a substantially cylindrical bearing assembly 36 fixed on the bottom wall 12a of the case body 12 and four arms 38 extending from the bearing assembly toward the magnetic disk. . The magnetic head assembly 20 is fixed to the extending end of each arm 38.
[0018]
Each magnetic head assembly 20 has an elongated suspension 40 formed by a leaf spring and a magnetic head 42 attached to the tip of the suspension. The suspension 40 may be integrally formed with the arm using the same material as the arm. The four arms 38 and the four magnetic head assemblies 20 are arranged such that the two magnetic heads 42 face each other with the magnetic disk interposed therebetween. Accordingly, when the carriage assembly 22 rotates about the bearing assembly 36, each magnetic head 42 can move to an arbitrary track of the corresponding magnetic disk.
[0019]
The VCM 24 is fixed to the substantially fan-shaped lower yoke 50 fixed to the bottom wall 12a of the case body 12, the substantially fan-shaped upper yoke 52 facing the lower yoke at a predetermined distance, and the inner surface of the lower yoke. A permanent magnet 54 facing the upper yoke.
[0020]
The VCM 24 further includes a voice coil 56 that is mounted on a support frame 58 that extends from the bearing assembly 36 of the carriage assembly 22 and is located between the upper yoke 72 and the permanent magnet 74. It can move between these. A magnetic field is generated by energizing the voice coil 56, and the carriage assembly 22 is rotated by the interaction with the magnetic field generated from the permanent magnet 54.
[0021]
As shown in FIGS. 2 to 4, in the present embodiment, the lower yoke 50 of the VCM 24 is provided embedded in the bottom wall 12 a of the case body 12. That is, the opening 60 is formed in the bottom wall 12 a, and the entire lower yoke 50 is accommodated in the opening 60. The lower surface of the lower yoke 50, that is, the outer surface, is located on the same plane as the outer surface of the bottom wall 12a.
[0022]
For example, the lower yoke 50 is bonded and fixed in the opening 60, and a tape 62 for preventing the lower yoke 50 from dropping is attached to the outer surface of the bottom wall 12a to cover the opening 60 and the outer surface of the lower yoke. .
[0023]
As shown in FIG. 1, the substrate unit 21 provided in the case 12 has a substrate body 64 installed on the inner surface of the bottom wall 12a, and a flexible wiring board 66 extending from the substrate body. . A plurality of electronic components and a first connector 67 are mounted on the board body 64. The first connector 67 passes through the substrate body 64 and the bottom wall 12a of the case body 12 and is exposed on the outer surface of the bottom wall. The extended end of the flexible wiring board 66 is fixed to the bearing assembly 36 of the carriage assembly 22 and is connected to the four magnetic heads 42 via wires (not shown).
[0024]
On the other hand, as shown in FIGS. 1 to 4, the printed circuit board 19 attached to the outer surface of the bottom wall 12a of the case body 12 is formed in a substantially rectangular shape, and a large number of electronic components 70 are mounted on the upper surface thereof. Yes. On the printed circuit board 19, a second connector 72 connectable to the first connector 67 on the board unit 21 side and a main connector 74 for connecting the HDD to an electronic device such as a personal computer are mounted. .
[0025]
The printed circuit board 19 is disposed opposite to the outer surface of the bottom wall 12a of the case body 12 with the second connector 72 connected to the first connector 67, and is fixed to the outer surface of the bottom wall by a plurality of screws 80. Yes. Here, the printed circuit board 19 has a circular through hole 76 formed at a position facing the bracket 27 of the spindle motor 18 and faces the bottom wall portion in which the lower yoke 60 of the VCM 24 is embedded. The part is notched.
[0026]
In a state where the printed circuit board 19 is attached to the outer surface of the bottom wall 12a, the bracket 27 of the spindle motor 18 is located in the through hole 76 of the printed circuit board, and the lower yoke 60 of the VCM 24 is embedded in the entire printed circuit board 19. It is arranged avoiding the bottom wall part. Therefore, the printed circuit board 19 is attached to the bottom wall 12a so as to be in close contact with the outer surface of the bottom wall 12a without being obstructed by the bracket 27 and the lower yoke embedded portion.
[0027]
According to the HDD configured as described above, the entire lower yoke 50 of the VCM 24 is embedded in the bottom wall 12a of the case body 12 to increase the VCM permanent magnet 54 in order to increase the driving force. Even in this case, a predetermined interval can be provided between the upper and lower yokes 52 and 54 without increasing the thickness of the case 10. This makes it possible to increase the number of mounted magnetic disks and increase the recording capacity without increasing the size of the entire HDD, and particularly without increasing the thickness of the HDD.
[0028]
Further, according to the HDD described above, the printed circuit board 19 provided facing the outer surface of the bottom wall of the case body 12 is notched at a portion facing the bottom wall portion in which the lower yoke 50 is embedded, so that the bottom wall It is provided to avoid the part. Therefore, the printed circuit board 19 can be provided in close contact with the outer surface of the bottom wall 12a of the case, and an increase in the thickness of the entire HDD including the printed circuit board can be suppressed.
[0029]
In addition, this invention is not limited to the Example mentioned above, A various deformation | transformation is possible within the scope of this invention. For example, in the above embodiment, the entire lower yoke of the VCM 24 is embedded in the bottom wall 12a of the case body 12, but as shown in FIG. 5, a recess 80 is formed on the inner surface of the bottom wall 12a. A portion of the lower yoke may be embedded and disposed. That is, by providing at least a part of the lower yoke embedded in the bottom wall of the case main body, the thickness of the HDD can be reduced, and the same effect as the above-described embodiment can be obtained. Moreover, according to this structure, the effect that the magnetic flux leakage from a lower yoke can be prevented can also be acquired.
In addition, the number of mounted magnetic disks is not limited to two and can be increased or decreased as necessary.
[0030]
【The invention's effect】
As described above in detail, according to the present invention, at least a part of the yoke constituting the voice coil motor is embedded in the bottom wall of the case, thereby increasing the size of the apparatus, in particular, without increasing the thickness. A magnetic disk device capable of increasing the storage capacity can be provided.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of an HDD according to an embodiment of the present invention.
FIG. 2 is a longitudinal sectional view of the HDD.
FIG. 3 is an exploded perspective view showing a bottom side of the HDD and a printed circuit board.
FIG. 4 is a perspective view showing a bottom side of the HDD.
FIG. 5 is a cross-sectional view showing a main part of an HDD according to a modification of the invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Housing | casing 12 ... Main body 12a ... Bottom wall 16a, 16b ... Magnetic disk,
DESCRIPTION OF SYMBOLS 18 ... Spindle motor 19 ... Printed circuit board 20 ... Magnetic head assembly 22 ... Carriage assembly 24 ... Voice coil motor 50 ... Lower yoke 52 ... Upper yoke 54 ... Permanent magnet 60 ... Opening 80 ... Recess

Claims (4)

A magnetic disk;
A spindle motor for holding and rotating the magnetic disk;
A magnetic head for recording and reproducing information on the magnetic disk;
A carriage assembly that supports the magnetic head movably with respect to the magnetic disk;
A voice coil motor that moves the carriage assembly to position the magnetic head at an arbitrary position on the magnetic disk;
A case having a bottom wall facing the magnetic disk and containing the magnetic disk, spindle motor, carriage assembly, and voice coil motor;
A mounting surface on which a plurality of electronic components are mounted, and a non-mounting surface that is opposed to the mounting surface and on which no electronic component is mounted, and the mounting surface faces the outer surface of the bottom wall of the case; A printed circuit board fixed to the case ,
The voice coil motor includes a pair of yokes opposed to each other at intervals, a magnet fixed to at least one of the yokes and disposed between the pair of yokes, and attached to the carriage assembly and the pair of yokes. A voice coil provided opposite to the magnet between the yokes,
One of the yokes is provided in a state where at least a part of the yoke is embedded in the bottom wall of the case,
In the printed circuit board, a portion facing the bottom wall portion in which the one yoke is embedded is cut out, and an outer surface of the bottom wall portion in which the one yoke is embedded is substantially the same as the non-mounting surface. A magnetic disk device, wherein the magnetic disk device is provided side by side in a plane .   2. The magnetic disk apparatus according to claim 1, wherein the bottom wall has an opening, and the one yoke is embedded in the opening and exposed to the outer surface of the bottom wall.   2. The magnetic disk drive according to claim 1, wherein the bottom wall has an opening, the one yoke is embedded in the opening, and the surface of the yoke is substantially flush with the outer surface of the bottom wall. . The bottom wall of the case has an opening provided facing the spindle motor, and the spindle motor has a motor lower part protruding to the outer surface of the bottom wall through the opening,
The magnetic disk drive according to claim 1, wherein the printed circuit board has a through hole that accommodates the lower part of the motor.

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