JP2002298571A - Magnetic disk unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic disk unit which can be stably operated even under a high-temperature environment by suppressing the rise of the temperature of electronic parts. SOLUTION: A heat radiation sheet 40 is disposed between the base surface of a case and a printed circuit board. The heat radiation sheet is integrally molded of a single elastic blank having thermal conductivity and has a thickness greater than the spacing between a base and the printed circuit board. Plural slits 54 are regularly lined up and formed at the heat radiation sheet. The respective slits are formed to the width below the thickness of the heat radiation sheet and the spacings between the adjacent slits are formed to half the thickness of the heat radiation sheet or below. The respective slits are disposed to incline in the thickness direction of the heat radiation sheet.

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, and more particularly to a magnetic disk drive having a base for storing a magnetic disk and a printed circuit board mounted on the base with a predetermined gap. .

[0002]

2. Description of the Related Art Generally, magnetic disks are widely used as memories for storing a large amount of information in computers such as personal computers, laptop computers, and book computers. Such a magnetic disk device, for example, a hard disk drive (hereinafter, referred to as an HDD) usually has a case that functions as a base formed of metal. In this case, there are a magnetic disk as a recording medium, a spindle motor for driving the magnetic disk to rotate, a magnetic head for recording and reproducing on the magnetic disk, and a carriage for supporting the magnetic head movably with respect to the magnetic disk. An assembly, a voice coil motor, and the like for driving the carriage assembly to move and position the magnetic head on a desired track of the magnetic disk are housed.

A printed circuit board for controlling the operation of the HDD is mounted on the outer surface of the bottom wall of the case with a predetermined gap. A plurality of electronic components are mounted on the printed circuit board and are located between the electronic component and the case.

[0004]

[0006] Such an HDD is
When used in a high-temperature environment, the temperature of the HDD itself becomes considerably high due to the heat generated by the HDD itself. In particular, the temperature of a specific IC mounted on a printed circuit board becomes high, and depending on the environmental temperature,
The guaranteed temperature may be exceeded. For example, 70
When the HDD is continuously read / written in a high-temperature environment of 70 ° C., the temperature of the case is 70 ° C. + α, but the specific IC or the like may exceed 100 ° C. In this case, the IC approaches its guaranteed temperature limit and causes malfunction of the HDD.

As a method of suppressing the temperature rise of the electronic parts as described above, it is conceivable to dispose a heat radiating sheet or the like in a gap between the printed circuit board and the case.
A heat dissipation sheet suitable for this has not been developed. That is, the gap between the printed circuit board and the case is 0.1 mm on average.
It is as narrow as about 3 mm and has irregularities. At the present time, a material that is thin, flexible, and excellent in thermal conductivity that can be arranged in such a gap has not been realized.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to provide a magnetic disk drive capable of suppressing a rise in the temperature of electronic components and operating stably even in a high-temperature environment.

[0007]

In order to achieve the above object, a magnetic disk drive according to the present invention comprises a base on which a magnetic disk is arranged, an electronic component mounted thereon, and a predetermined gap. A printed circuit board provided facing the base, and a heat dissipation sheet formed integrally with a single elastic material having thermal conductivity and sandwiched between the base and the printed circuit board, The heat radiation sheet has a thickness equal to or greater than the gap between the base and the printed circuit board, and has a plurality of slits formed in a regular array, and each of the slits is The heat dissipation sheet is formed to have a width equal to or less than the thickness of the heat dissipation sheet, the interval between adjacent slits is formed to be less than half the thickness of the heat dissipation sheet, and each of the slits is inclined with respect to the thickness direction of the heat dissipation sheet. Provided It is characterized in.

According to the magnetic disk drive of the present invention, the heat radiating sheet has a plane shape substantially equal to that of the printed circuit board, and the slit covers almost the entire surface except for the peripheral edge of the heat radiating sheet. Parallel to each other and
It is characterized by being formed at equal intervals.

Further, according to the magnetic disk drive of the present invention, the plurality of slits are provided to be inclined at the same angle with respect to the thickness direction of the heat radiation sheet.

According to the magnetic disk drive configured as described above, the heat radiation sheet has a plurality of slits, and these slits are formed in the above-described width and interval.
Since the heat dissipation sheet is inclined with respect to the thickness direction, when this heat dissipation sheet is sandwiched between the base and the printed circuit board, each slit is crushed, and bridge portions located between adjacent slits overlap each other. It is arranged in a state.

Therefore, even if the heat radiation sheet is a sheet thicker than the gap between the base and the printed circuit board, it can be easily arranged between the base and the printed circuit board. Therefore, the heat radiating sheet can be formed by an elastic material having high heat conductivity, and the heat radiating property of the electronic component can be improved. As a result, it is possible to provide a magnetic disk device capable of suppressing a rise in the temperature of electronic components and operating stably even in a high-temperature environment.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which a magnetic disk drive of the present invention is applied to an HDD will be described below in detail with reference to the drawings. As shown in FIG.
Is provided with a case 12 functioning as a base. The case 12 is formed in a rectangular box shape with an open upper end, and the upper opening is closed by screwing a top cover (not shown).

Inside the case 12, 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 and from the magnetic disks , A plurality of magnetic head assemblies 20, a carriage assembly 22 rotatably supporting these magnetic head assemblies, a voice coil motor 24 for rotating and positioning the carriage assembly, and a substrate unit 21 having a preamplifier and the like. It is stored.

The two magnetic disks 16a and 16bc are
The hub is fitted on the hub of the spindle motor 18 and stacked along the axial direction of the hub. Then, the magnetic disk 16
A and 16b are fixed by a disk-shaped clamper 16 screwed to the upper end of the hub, and are driven to rotate at a predetermined speed by a spindle motor 18.

The carriage assembly 22 includes a case 1
Substantially cylindrical bearing assembly 26 fixed on the bottom wall of the second
And 4 extending from the bearing assembly toward the magnetic disk.
And a book arm 25. And each arm 2
5, a magnetic head assembly 20 is fixed to the extension end.
By rotating the carriage assembly 22 about the bearing assembly 26, each magnetic head can move to an arbitrary track on the corresponding magnetic disk.

The VCM 24 includes a pair of yokes 28 fixed to the inner surface of the bottom wall of the case 12 and opposed at a predetermined interval.
And a permanent magnet (not shown) fixed to the inner surface of one of the yokes. Further, the VCM 24 has a voice coil (not shown) attached to the carriage assembly 22, and this voice coil is located between one yoke and the permanent magnet. Then, by energizing the voice coil, the carriage assembly 22 is rotated.

The board unit 21 has a board body installed on the inner surface of the bottom wall of the case 12 and a flexible wiring board 32 extending from the board body. A plurality of electronic components including the connector 30 are mounted on the board body.
The connector 30 penetrates through the board body and the bottom wall of the case 12 and is exposed on the outer surface of the bottom wall. The extending end of the flexible wiring board 32 is fixed to the bearing assembly 26 of the carriage assembly 22 and is connected to the four magnetic head assemblies 20 via wiring (not shown).

On the other hand, a printed circuit board 34 for controlling the operations of the spindle motor 18, the voice coil motor 24 and the magnetic head assembly 20 is screwed to the outer surface of the bottom wall of the case 12, and a predetermined gap is formed between the outer surface of the bottom wall and the printed circuit board. Placed and facing. Further, between the case 12 and the printed circuit board 34, a heat radiating sheet 40 described later is sandwiched.

The printed circuit board 34 is formed in a substantially rectangular shape, and a large number of electronic components 38 are mounted on the upper surface thereof. On the printed circuit board 34, a connector 42 connectable to the connector 30 on the board unit 21 side and a main connector 44 for connecting the HDD to an electronic device such as a personal computer are mounted.

The printed circuit board 34 is disposed facing the outer surface of the bottom wall of the case 12 with the connector 42 connected to the connector 30 on the case 12 side, and is fixed to the outer surface of the bottom wall by a plurality of screws 50. ing. The gap between the outer surface of the bottom wall of the case 12 and the printed circuit board 34 is set to about 0.3 mm on average. It is to be noted that the spindle motor 18 is provided substantially at the center of the printed circuit board 34.
Is formed with a circular through hole 36 for allowing a bracket (not shown) to escape.

As shown in FIGS. 1 to 4, the heat dissipation sheet 40 is integrally formed of a single elastic material having thermal conductivity, for example, rubber having a volume resistivity of 1E + 13 Ωcm or more. They are formed in substantially the same planar shape. The thickness T of the heat dissipation sheet 40 is formed to be equal to or greater than the gap between the outer surface of the bottom wall of the case 12 and the printed circuit board 34, for example, about 0.5 mm.

A through hole 46 corresponding to the through hole 36 of the printed circuit board 34 is formed substantially at the center of the heat radiation sheet 40. Furthermore, a large number of linear slits 54 are regularly arranged on substantially the entire surface of the heat dissipation sheet 40 except for the peripheral edge thereof.

That is, these slits 54 are formed parallel to each other and at equal intervals. The width t1 of each slit 54 is formed to be equal to or less than the thickness T of the heat dissipation sheet 40, for example, 0.3 mm. Further, the interval between the adjacent slits 54, that is, the adjacent slits 54
The width t2 of the bridge portion 55 located between the heat dissipation sheets 4
It is formed to a half or less of the thickness of 0, for example, 0.2 mm.

Further, the plurality of slits 54 are formed so as to be uniformly inclined with respect to the thickness direction of the heat radiation sheet 40, that is, the direction perpendicular to the surface of the heat radiation sheet. The inclination angle is set to, for example, 45 °.

The heat dissipation sheet 40 constructed as described above
Is disposed between the outer surface of the bottom wall of the case 12 and the printed circuit board 34. As shown in FIG. 4, when the heat dissipation sheet 40 is sandwiched between the outer surface of the bottom wall of the case 12 and the printed circuit board 34, each of the slits 54 is crushed, and the bridge portions 55 located between the adjacent slits are separated from each other. It is in an overlapping state, and is elastically deformed along the unevenness of the electronic component 38 on the printed circuit board 34 and the bottom of the case.

According to the HDD configured as described above,
The heat dissipating sheet 40 has a plurality of slits 54. These slits are formed in the above-described width and interval, and are inclined with respect to the thickness direction of the heat dissipating sheet. By being sandwiched between the slits, the slits are crushed, and the bridge portions located between the adjacent slits are elastically deformed so as to overlap each other, and can flexibly cope with the gap between the case 12 and the printed circuit board 34. .

Therefore, even when the heat radiating sheet 40 is a sheet thicker than the gap between the case 12 and the printed circuit board 34, it can be easily arranged between the case and the printed circuit board. Therefore, the heat radiation sheet 40 can be formed of an elastic material having a high heat transfer property,
The heat dissipation of the electronic component 38 can be improved. For example, by disposing the heat radiating sheet 40, the heat of the electronic component 38 can be released to the case 12 by 10 ° C. or more. As a result, it is possible to suppress a rise in the temperature of the electronic component 38 and obtain an HDD that can operate stably even in a high-temperature environment.

The present invention is not limited to the above-described embodiment, but can be variously modified within the scope of the present invention. For example, the material of the heat radiating sheet can be appropriately selected as long as it has high heat transferability and elasticity. Further, the number, shape, dimensions, and the like of the slits are not limited to the above-described embodiment, but can be variously modified as needed.

[0029]

As described in detail above, according to the present invention, by providing a heat radiating sheet between the base and the printed circuit board, it is possible to suppress the temperature rise of the electronic components and to stabilize even under a high temperature environment. And a magnetic disk device operable in the above manner.

[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 plan view showing a heat dissipation sheet of the HDD.

FIG. 3 is a cross-sectional view of the heat radiation sheet taken along line AA in FIG. 2;

FIG. 4 is an exemplary sectional view showing a bottom portion of the HDD;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... HDD 12 ... Case 16a, 16b ... Magnetic disk, 18 ... Spindle motor 20 ... Magnetic head assembly 22 ... Carriage assembly 24 ... Voice coil motor 34 ... Printed circuit board 38 ... Electronic components 40 ... Heat dissipation sheet 54 ... Slit 55 ... Bridge section

Claims (4)

[Claims] 1. A base on which a magnetic disk is arranged, a printed circuit board on which electronic components are mounted, and which is provided opposite to the base with a predetermined gap therebetween, having a thermal conductivity. Integrally molded with a single elastic material
A heat dissipation sheet sandwiched between the base and the printed circuit board, wherein the heat dissipation sheet has a thickness equal to or greater than a gap between the base and the printed circuit board, and regularly. It has a plurality of slits formed side by side, each of the slits is formed to have a width equal to or less than the thickness of the heat dissipation sheet, and the interval between adjacent slits is formed to be less than half the thickness of the heat dissipation sheet. A magnetic disk drive, wherein each of the slits is provided to be inclined with respect to a thickness direction of the heat dissipation sheet. 2. The heat dissipation sheet has a plane shape substantially equal to that of the printed circuit board, and the slits are substantially parallel to each other at equal intervals over substantially the entire surface except the peripheral edge of the heat dissipation sheet. The magnetic disk drive according to claim 1, wherein the magnetic disk drive is formed. 3. The magnetic disk drive according to claim 1, wherein the plurality of slits are provided at the same angle with respect to the thickness direction of the heat radiation sheet. 4. The heat dissipation sheet according to claim 1, wherein each of the slits is crushed, and bridge portions located between the adjacent slits are sandwiched between the base and the printed circuit board in a state of being overlapped with each other. 4. The magnetic disk drive according to claim 1, wherein: