Air breather with waterproof fiber material for magnetic disk drive

Embodiments in accordance with the present invention provide a magnetic disk drive that reliably prevents entry of water or other form of liquid through a breathing hole for the enhanced performance, reliability, and the like. In one embodiment, a box body forming part of a hard disk drive (HDD) has a top cover. The top cover includes a breathing hole drilled therein. The breathing hole serves to eliminate any pressure difference between an inside and an outside of the HDD. A fiber waterproof body, which includes a waterproof fiber material or the like, is fitted in a large-diameter hole of the breathing hole. A pore waterproof body, formed by bundling up a large number of slender pores, is mounted in a small-diameter hole of the breathing hole.

CROSS-REFERENCE TO RELATED APPLICATION

The instant nonprovisional patent application claims priority to Japanese Application No. 2006-095748 filed Mar. 30, 2006 and incorporated by reference in its entirety herein for all purposes.

BACKGROUND OF THE INVENTION

A known magnetic disk drive typically includes a breathing hole drilled in an outer wall surface thereof, the hole providing communication between an outside and an inside of the drive. Atmosphere flows in and out of the drive through this breathing hole. Differential pressure between the inside and the outside of the drive produced during starting to rotate a magnetic disk or the like is thereby eliminated, so that the drive can be kept in a fully operational condition. (See, for example, Japanese Laid-Open Patent No. Sho 62-73484)

The magnetic disk drive has conventionally and commonly been used in a personal computer or the like that is fixedly installed indoors. This common application has precluded circumstances, in which water or other form of liquid enters the magnetic disk drive. Because of a new application of the magnetic disk drive arising lately in the field of CE (MP3 (MPEG Audio layer-3) players, cellular phones, mobile computers, and the like), however, there is greater likelihood that water or other form of liquid will enter the disk drive as a result of submersion under water, rainwater, and the like. The magnetic disk drive is a type of precision equipment and entry of water or other form of liquid in the magnetic disk drive is not desirable.

BRIEF SUMMARY OF THE INVENTION

Embodiments in accordance with the present invention provide a magnetic disk drive that reliably prevents entry of water or other form of liquid through a breathing hole for the enhanced performance, reliability, and the like. In accordance with the particular embodiments shown inFIGS. 2-4, a box body10forming part of a hard disk drive (HDD)1has a top cover12. The top cover12includes a breathing hole20drilled therein. The breathing hole20serves to eliminate any pressure difference between an inside and an outside of the HDD1. A fiber waterproof body30, which includes a waterproof fiber material32or the like, is fitted in a large-diameter hole21of the breathing hole20. A pore waterproof body40, formed by bundling up a large number of slender pores42A, is mounted in a small-diameter hole22of the breathing hole20.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments in accordance with the present invention relate to a magnetic disk drive, such as, for example, a hard disk drive.

An object of embodiments of the present invention is to provide a magnetic disk drive that reliably prevents entry of water or other form of liquid through a breathing hole for the enhanced performance, reliability, and the like.

To solve the problems described above, a magnetic disk drive is provided. The magnetic disk drive includes a box body that has a head disk assembly built therein for writing data to, and reading data from, a magnetic recording medium. The box body includes a wall surface which has a breathing hole drilled therein to penetrate therethrough. Further, the breathing hole includes a waterproof body disposed therein. The waterproof body has a plurality of pores. The waterproof body prevents entry of a liquid in the box body by using surface tension of the liquid when the liquid enters the pores.

A specific embodiment to which the present invention is applied will be described below with reference toFIGS. 1 and 2.

A magnetic disk drive I (hereinafter referred to as HDD1) according to an embodiment of the present invention is, for example, a hard disk drive. Referring toFIGS. 1 and 2, the HDD1includes a box body10, a fiber waterproof body30, a pore waterproof body40, and a built-in filter unit50.

The box body10is formed from a metallic material such as a steel sheet into a rectangular parallelepiped cabinet. The box body10includes a box body main body11and a top cover12. The box body main body11is a bottomed rectangular tube having one in a thickness direction of the box body10(a lower end side inFIG. 2) closed and another side (an upper end side inFIG. 2) opened. The top cover12, which is a substantially rectangular flat sheet, closes the open side of the box body main body11. The box body main body11includes a first side wall portion11A, a second side wall portion11B, a third side wall portion1C, a fourth side wall portion11D, and a bottom wall portion11E integrally formed with each of the four side wall portions11A to11D. The top cover12, the side wall portions11A to11D, and the bottom wall portion11E correspond to “wall surfaces” in the appended claims.

The box body10has the following elements built therein: specifically, a plurality of magnetic recording disks14(only one is shown in the figure) rotatably driven by a spindle motor (not shown); a head gimbal assembly15; magnetic heads (not shown) that write data to, and/or read data from, the magnetic recording disks14; and the like. The spindle motor, the magnetic recording disks14, the head gimbal assembly15, the magnetic heads, and the like collectively called a head disk assembly.

The top cover12includes a breathing hole20. The breathing hole20includes a circular stepped hole disposed on a side of a corner formed between the first side wall portion11A and the third side wall portion11C of the box body main body11. Referring toFIG. 2, the breathing hole20includes a large-diameter hole21and a small-diameter hole22. The large-diameter hole21is an upper side portion of the breathing hole20. The small-diameter hole22is disposed immediately below the large-diameter hole21, forming a lower side portion of the breathing hole20. Air or other form of gas flows in and out of the box body10through the breathing hole20. Accordingly, the breathing hole20is assigned with a function of eliminating any difference in pressure, temperature, and the like between an inside and an outside of the box body10.

Referring toFIG. 3, the fiber waterproof body30includes a fiber mounting frame31and a waterproof fiber material32fitted in the fiber mounting frame31. The fiber mounting frame31is formed into an annular frame body from, for example, plastic. The fiber mounting frame31is fitted into the large-diameter hole21of the breathing hole20and secured therein using an adhesive or the like. The waterproof fiber material32, on the other hand, is formed into a disk shape using, for example, a high water-absorption resin formed from a crosslinked body of a hydrophilic, straight-chain or branched polymer. The waterproof fiber material32is fixedly mounted in the fiber mounting frame31. The high water-absorption resin is a porous body having a three-dimensional network structure. When in contact with water, the resin absorbs water with its force of being dissolved in water. The resin thereby inhibits entry of water or other form of liquid through the breathing hole20into the box body10, while allowing passage of air.

Referring toFIG. 4, the pore waterproof body40includes a pore mounting case41and a waterproof porous material42fitted in the pore mounting case41. The pore mounting case41is formed into a cylinder using, for example, plastic. The pore mounting case41is fitted into the small-diameter hole22of the breathing hole20and secured therein using an adhesive or the like. The waterproof porous material42includes a plurality of pores42A formed therein. These pores42A extend slenderly along an axial direction of the pore mounting case41. The waterproof porous material42is fixedly mounted in the pore mounting case41. The waterproof porous material42of the pore waterproof body40blocks off, with the fiber waterproof body30, liquid that would otherwise enter the box body10by using surface tension of the liquid as the liquid enters each of the pores42A.

The built-in filter unit50includes a filter51, an inner unit case52, and an outer unit case53. The built-in filter unit50is disposed on an inner surface of the top cover12so as to cover the breathing hole20. The filter51is formed from a gas adsorbent that includes activated carbon, silica gel, or the like. The inner unit case52includes a side surface portion52A, an upper surface portion52B, and another upper surface portion52C. The side surface portion52A is shaped into a cylindrical column. The upper surface portion52B extends radially inwardly from a proximal end portion of the side surface portion52A. The upper surface portion52C, on the other hand, extends radially inwardly from a distal end portion of the side surface portion52A.

In addition, the outer unit case53includes a side surface portion53A, an annular upper surface portion53B, and a lower surface portion53C. The side surface portion53A is fitted and secured over an outer peripheral side of the side surface portion52A of the inner unit case52. The upper surface portion53B extends radially inwardly from an upper end portion of the side surface portion53A. The upper surface portion53B is physically joined up against the upper surface portions52B,52C of the inner unit case52. The lower surface portion53C closes an opening end on a lower side of the side surface portion53A. Having the upper surface portion53B disposed on an outer edge side of the small-diameter hole22of the breathing hole20, the outer unit case53is fixedly attached to the inner surface of the top cover12using an adhesive or the like. The lower surface portion53C of the outer unit case53is formed from a member having breathability.

An annular water repellent material54is fixedly mounted on an outer surface of the top cover12. The water repellent material54is disposed on an outer edge side of the large-diameter hole21of the breathing hole20.

The HDD1having arrangements as described heretofore according to the embodiment of the present invention is adapted to use the magnetic head disposed on a leading end side of the head gimbal assembly15to write data to, and/or read data from, each of the plurality of magnetic recording disks14rotatably driven by the spindle motor built into the box body10.

The HDD1according to the embodiment of the present invention has the fiber waterproof body30and the pore waterproof body40mounted in the breathing hole20in the box body10. Accordingly, should water or other form of liquid enter in the breathing hole20in the HDD1in a direction of an arrow A ofFIG. 2, the liquid can be reliably adsorbed by the fiber waterproof body30and the pore waterproof body40.

Consequently, according to the embodiment of the present invention, the fiber waterproof body30and the pore waterproof body40eliminate the problem of entry of water or other form of liquid in the box body10, thereby enhancing performance, reliability, and the like of the HDD1.

Moreover, the built-in filter unit50is disposed in the box body10so as to close the breathing hole20. The gas adsorbent including activated carbon, silica gel, or the like, built into the built-in filter unit50can effectively remove harmful gases entering the box body10via the breathing hole20in a direction of an arrow B ofFIG. 2. Performance, reliability, and the like of the HDD I can therefore be even further enhanced.

FIGS. 5 through 8are views showing another embodiment of the present invention. In the descriptions that follow, like reference numerals refer to like parts and duplicate descriptions will be omitted.

Referring toFIG. 5, an HDD60according to another embodiment of the present invention includes a box body10, a fiber waterproof body80, and a built-in filter unit50.

A top cover12of the box body10includes a breathing hole70. The breathing hole70includes a circular stepped hole disposed on a side of a corner formed between a first side wall portion11A and a third side wall portion11C of a box body main body11. Referring toFIG. 5, the breathing hole70includes a large-diameter hole71and a small-diameter hole72. The large-diameter hole71is an upper side portion of the breathing hole70. The small-diameter hole72is disposed immediately below the large-diameter hole71, forming a lower side portion of the breathing hole70.

Referring toFIG. 6, the fiber waterproof body80includes a waterproof fiber material90clamped by an annular sheet81formed, for example, from a plastic or metallic sheet. The fiber waterproof body80is fitted and fixed in the large-diameter hole71of the breathing hole70using an adhesive or the like.

According to this embodiment of the present invention, the fiber waterproof body80and the waterproof fiber material90eliminate the problem of entry of water or other form of liquid in the box body10. Electronic data typically recorded in the magnetic recording disks14can be prevented from being destroyed and performance, reliability, and the like of the HDD60can thereby be enhanced.

FIGS. 9 through 11are views showing still another embodiment of the present invention. In the descriptions that follow, like reference numerals refer to like parts and duplicate descriptions will be omitted.

Referring toFIG. 9, an HDD100according to this embodiment of the present invention includes a box body10, a first fiber waterproof body110, a second fiber waterproof body120, and a built-in filter unit50.

Referring toFIG. 10, the first fiber waterproof body110includes a fiber mounting frame111and a waterproof fiber material112fitted and secured in the fiber mounting frame111. The fiber mounting frame111is formed into an annular frame body from, for example, plastic. The fiber mounting frame111is fitted and fixed in a large-diameter hole21of the breathing hole20using an adhesive or the like.

The waterproof fiber material112is mixed with a water-absorbing polymer. When the waterproof fiber material112absorbs water, the water-absorbing polymer swells to fill gaps between fibers of the waterproof fiber material112.

Referring toFIG. 11, the second fiber waterproof body120includes a fiber mounting case121and a waterproof fiber material122fitted and secured in the fiber mounting case121. The fiber mounting case121is formed into a tubular body using, for example, plastic. The fiber mounting case121is disposed in a small-diameter hole22of the breathing hole20with a clearance allowed therebetween. The waterproof fiber material122of the second fiber waterproof body120is secured to a surface of the waterproof fiber material112of the first fiber waterproof body110using an adhesive or the like.

The waterproof fiber material122shares the same composition as the waterproof fiber material112and is mixed with a water-absorbing polymer. When the waterproof fiber material122absorbs water, the water-absorbing polymer swells to fill gaps between fibers of the waterproof fiber material122.

According to the embodiment of the present invention having the arrangements as described above, when water or other form of liquid enters the breathing hole20, the water-absorbing polymer mixed with the waterproof fiber materials112,122of the first and the second fiber waterproof bodies110,120swells to fill the gaps between the fibers of the waterproof fiber materials112,122. Accordingly, the waterproof fiber materials112,122can even more reliably block off entry of the liquid in the box body10through the breathing hole20. Performance, reliability, and the like of the HDD100can therefore be enhanced even further.

FIGS. 12 and 13are views showing a further embodiment of the present invention. In the descriptions that follow, like reference numerals refer to like parts and duplicate descriptions will be omitted.

Referring toFIG. 12, an HDD130according to this embodiment of the present invention includes a box body10, a breathable member140, a flexible container150, and a water-absorbing polymer160.

The breathable member140is formed into a disk from a hard resin material or the like. The breathable member140has a large number of vent holes (not shown) drilled in a surface thereof through a width direction. In addition, the breathable member140includes a water supply port140A drilled at a center thereof. Further, the breathable member140is removably mounted to a bottom surface of a large-diameter hole21forming part of a breathing hole20using a screw (not shown) or the like.

The flexible container150is formed into a bottomed cylinder using, for example, a resin material or the like having elasticity. The flexible container150has an opening end side fixedly mounted to the breathable member140.

The water-absorbing polymer160is accommodated in the flexible container150. When water or other form of liquid enters the flexible container150through the water supply port140A in the breathable member140, the water-absorbing polymer160absorbs the liquid to swell as shown inFIG. 13.

According to this embodiment of the present invention having the arrangements as described above, when water or other form of liquid enters the breathing hole20, the liquid enters the flexible container150by way of the water supply port140A in the breathable member140. The water-absorbing polymer160then absorbs the liquid. As a result, the water-absorbing polymer160swells with the flexible container150as shown inFIG. 13. The flexible container150and the water-absorbing polymer160then serve as a sealing plug that seals the breathing hole20, thereby reliably blocking entry of the liquid through the breathing hole20.

In this embodiment of the present invention described above, the flexible container150is a cylindrical body extending straight in an axial direction thereof. The present invention is not limited to this arrangement; rather, as shown, for example, in a modified example shown inFIG. 14, a flexible container150′ may be formed into a bellows shape. Even with this arrangement, when water or other form of liquid enters the breathing hole20, the liquid enters the flexible container150′ by way of the water supply port140A in the breathable member140. The water-absorbing polymer160then absorbs the liquid. As a result, the water-absorbing polymer160swells as shown inFIG. 15. This stretches the flexible container150′ axially. The flexible container150′ and the water-absorbing polymer160then function as a sealing plug that seals the breathing hole20, thereby reliably blocking entry of the liquid through the breathing hole20.

The preferred embodiments of the present invention have been described with reference to the arrangement, in which the pore waterproof body40as a waterproof body is fitted in the small-diameter hole22of the breathing hole20. The present invention is not, however, limited to this arrangement and, for example, the fiber waterproof body120may be fitted in the small-diameter hole22of the breathing hole20.