JPH08161861A - Magnetic disk device - Google Patents

Abstract

PURPOSE: To maintain the inside of a head disk assembly(HDA) at low humidity at all times by providing the part near the respiration hole of a passage from the respiration hole to the HDA or the side face of the passage with a member which absorbs moisture at the time of inflow of the outdoor air into the HDA or allows water drops to evaporate of themselves. CONSTITUTION: The surface on the outer side of the HDA of a cover 8 of the magnetic disk device is provided with the respiration hole 21a and is further provided with the passage 8a for controlling the steam inflow from outside. The passage 8a is internally provided with the absorbent material 1 formed of a resin (for example, sponge, etc.) or chemical fibers, etc., which are capable of absorbing moisture and allowing the moisture to evaporate of itself and do not deteriorate the life of the magnetic disk device as a blank by adhesion or fitting at the end where the passage direction of the outdoor air changes first from the respiration hole 21a and in a position as nearest the respiration hole 21a as possible. An external filter 22 which prevents the infiltration of the duct into the HDA from outside is placed on a cover 8 surface right under the respiration hole 21a and a hermetic seal 21 provided with the hole of the respiration hole 21a is stuck and fixed to the position covering the filter 22.

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, and more particularly to a head disk assembly (hereinafter referred to as HDA).
The present invention relates to a magnetic disk device suitable for keeping the inside always at low humidity.

[0002]

2. Description of the Related Art The basic structure of a conventional magnetic disk device will be described with reference to FIGS. 17 is a cross-sectional view of a conventional magnetic disk device, FIG. 18 is a top view of the conventional magnetic disk device in a cover open state, and FIG. 21 is a top view of the conventional magnetic disk device. FIG. 17
In FIG. 18, the disk 5 is made of aluminum or glass as a substrate material and has a magnetic film formed on its surface.
Information is magnetically recorded, and is rotationally driven by the spindle motor 6. The head 4 floats on the surface of the disk 5 that is being rotationally driven while maintaining a constant space of about 0.1 micron, and magnetically writes or reads information. Head 4 that performs this writing or reading
Is made of a material whose mainstream is a ferrite or metal thin film having an electromagnetic coil for converting an electric signal and a magnetic field. The carriage 3 accurately positions the head 4 on the surface of the disk 5, and is made of aluminum or magnesium. The carriage 3 is driven and positioned by the voice coil motor 2. The voice coil motor 2 includes a coil 9 formed by winding an aluminum wire or a copper wire having an insulating film in a wound state, a magnet 2a made of a permanent magnet, and a yoke 2b for supporting the magnet 2a and forming a magnetic circuit. To be done. Here, one pair of magnets 2a is provided on the upper side in FIG. 17 (not shown), and one pair is provided on the lower side in FIG. 17 (not shown). The pair of magnets 2a provided on the upper side are separated at the center position (line 35 in FIG. 18) of the angle at which the head 4 moves to write or read information on the surface of the disk 5.
Each magnet 2a is arranged in the direction of rotation of the coil 9 and is fixed to the upper yoke 2b. Similarly, a pair of magnets 2a provided on the lower side
Are separated at the center position (line 35 in FIG. 17) of the angle at which the head 4 moves to write or read information on the surface of the disk 5, and each magnet 2a is arranged in the direction of rotation of the coil 9. And are fixed to the lower yoke 2b. Here, the pair of magnets 2a provided on the upper side is formed so that one has an N pole and the other has an S pole. Further, the pair of magnets 2a provided on the lower side are formed so as to have the opposite polarities to the magnets 2a on the upper side facing each other. With respect to the voice coil motor 2 configured as described above, the carriage 3 is driven and positioned by flowing a current while controlling the electric power amount and the current direction of the coil 9.

Signals when the head 4 is read and written are
Through the carriage 3 through a thin wire (not shown) of an electromagnetic coil provided in
A read / write control board 12 for controlling signals at the time of reading / writing of the head 4 via an FPC) 14a (FIG. 18).
Is transmitted to Further, it is transmitted from the read / write control board 12 to the outside of the HDA via the FPC 29. Also, HD
A circuit board 11 for controlling devices other than A is provided. Further, in the event of an abnormality, a current larger than a specified value flows through the coil 9, the carriage 3 runs away, and the head 4 is prevented from damaging the disk 5, or the head 4 is prevented from falling off the surface of the disk 5. It is provided. The spindle motor 6, the rotation center shaft of the carriage 3, and the voice coil motor 2 are fixed to the base 7, and the cover 8 has a cover screw 31 (see FIGS. 17 and 21).
It is fixed to the base 7 by. A packing 28 is provided between the cover 8 and the base 7 to have a structure for sealing the HDA. Thus, as a structure for sealing the HDA using the packing 28, for example, Japanese Patent Application Laid-Open No. 4-132072 (hereinafter referred to as a first conventional example).
It is described in.

Here, the HDA cover 8 is provided with a breathing hole portion 20 as shown in FIG. The breathing hole portion 20 has a function of suppressing the inflow of water vapor contained in the outside air from the breathing hole 21a (see FIGS. 19 and 20). 19 is a cross-sectional view showing an example of the breathing hole portion 20, and FIG. 20 is an upper surface explanatory view showing the breathing hole 21a and the passage 8a shown in FIG. In this conventional example, the passage 8a is composed of the breathing hole 21a and the passage 8a, and is configured to adjust the pressure difference between the inside closed from the outside air and the outside air by the packing 28 (FIG. 17). That is, the outside air flows in through the breathing hole 21a, and H of the cover 8
A thin and long passage 8 is formed by attaching a groove formed on the inner surface of the DA by a cutting or precision mold and a moisture-proof sheet 33 made of a material that does not allow moisture to pass through an adhesive to the upper surface thereof.
a is formed, the diffusion of the water vapor contained in the outside air is delayed while the outside air is passing through the inside, and only the dried dry air reaches the final end of the passage 8a, and the moisture-proof sheet is formed. The structure is such that the dust passes through the holes 33 and is captured by the external filter 22 and reaches the inside of the HDA.

Further, a structure for suppressing the inflow of water vapor contained in the outside air from the breathing hole 21a is described in, for example, Japanese Patent Application Laid-Open No. 62-281186 (hereinafter referred to as a second conventional example).

A structure for providing a hygroscopic agent in the HDA is described in, for example, Japanese Patent Application Laid-Open No. 63-298887 (hereinafter referred to as a third conventional example).

A structure for mounting a gas adsorbent in the HDA is described in, for example, Japanese Patent Laid-Open No. 4-134783 (hereinafter referred to as a fourth conventional example).

Furthermore, recently, as a structure for hermetically sealing the HDA, an HDA which uses a thin sheet-like hermetic seal with an adhesive on one surface is used in the gap between the base 7 and the cover 8 without using the packing 28. Exists.

Further, in the HDA, in an operation state of writing or reading information between the head 4 and the disk 5, in order to accurately process the signal, an inclusion should not enter the space and disturb the magnetic field. Therefore, it must always be kept clean. Therefore, as shown in FIG. 18, an internal filter 13 is provided so that the internal dust is captured by the air circulation inside the HDA generated by the rotation of the disk 5.

Further, since the magnetic disk device is required to have a small size and a large capacity, a high density recording and a high reliability, a plurality of disks 5 are mounted to obtain a storage capacity. Since the heads 4 are respectively present on the surfaces of the plurality of disks 5, a disk spacer (not shown) is provided between the disks 5 to finish the head 4 mounting surface of the carriage 3 with high accuracy. Head 4
I try to keep a constant interval with. From the above structure, H
The contact resistance between the head 4 and the disk 5 of the DA is directly related to the life of the device, and depending on the situation of the failure, the stored information cannot be read out, or if it deteriorates further, all the information stored in the device can be read out. It may be impossible.
Even today, the application fields of magnetic disk devices, which are becoming smaller and have a larger capacity, higher density recording, and higher reliability, are expanding their application fields, and the impact of failure will be an important social issue. Is starting to get worse.

Here, the initial phenomenon of the above-mentioned important obstacle is mainly due to the head 4 colliding with the disk 5. One of the causes is that the outside air enters the HDA, and the dust contained in the outside air is present between the head 4 and the disk 5, so that the floating stability of the head 4 is impaired. It is a thing. Further, once the collision between the head 4 and the disk 5 occurs, it has a property of being acceleratedly deteriorated by the broken pieces and the dust which come out from the both due to the collision.

Further, the water vapor contained in the outside air is the breathing hole portion 2.
0 (FIG. 17) or the like may flow into the HDA.
The inflowing moisture corrodes the parts used in the HDA,
Not only the deterioration is accelerated and the service life is adversely affected, but the phenomenon that the head 4 is attracted to the surface of the disk 5 when the apparatus is stopped due to the increase in the humidity in the HDA, and the spindle motor 6 cannot rotate at the time of start-up. Occur.

FIG. 21 is a top view of a conventional magnetic disk apparatus, in which a cover 8 is provided with a breathing hole 21a and a sheet 32, and a printing section 27 is provided on the sheet 32.
On the printing unit 27, the serial number of the device is printed.
As described above, the cover 8 is attached to the base 7 by the cover screw 31 (see FIG. 17). Further, in FIG. 21, reference numeral 29 indicates an FPC.

[0014]

In the magnetic disk device which is becoming more and more diversified in the future, the demand for the magnetic disk device aiming at thinness for mounting in a notebook type personal computer is increasing along with the miniaturization of the capacity. Therefore, in view of such market conditions, it is necessary to further reduce the size and thickness in the future.

On the other hand, with respect to the magnetic disk device mounted on the device control board 19 in a large computer which requires a large capacity for image processing and the like, it is essential to increase the processing speed (access time).

In addition, the price of any device is reduced,
Needless to say, higher reliability (longer life) is required.

According to the first conventional example (FIGS. 17 to 21), the packing 28 seals the inside of the HDA. However, the problem that the humidity of the outside air penetrates into the HDA, the problem that the gas that is harmful to the HDA is generated depending on the material of the rubber that constitutes the packing 28, and the rubber or resin (sponge) that is the material becomes elastic over time. There is a problem that the characteristics such as deteriorate, and the pressure is not applied between the cover 8 and the base 7 so that the sealing cannot be performed. Also, because of the property that it deteriorates and cannot be sealed as described above,
In order to avoid this and keep the HDA sealed for a long period of time, it is necessary to uniformly compress the entire surface with a constant force and secure a shrinkage allowance suitable for the material of the packing 28, which also causes a problem in productivity. .

Further, the packing 28 described above causes the HD
In addition to the structure for sealing the inside of A, as described above, recently, there is an HDA which uses a thin sheet-like hermetic seal having an adhesive on one side in the gap between the base 7 and the cover 8.
However, the current usage of the hermetic seal is used only for the purpose of hermetically sealing between the base 7 and the cover 8 and the description of the caution label printed in advance on the hermetic seal, so it is used in combination with other technical elements. In addition, it is necessary to reduce the number of parts.

Further, the breathing hole portion 20 shown in FIGS. 19 and 20.
Has the following problems. That is, in normal use, the outside air flows into the HDA from the breathing hole 21a because the pressure inside the HDA is high when the temperature inside the HDA is higher than the outside air and the atmospheric pressure is high.
It is the time when the temperature continues to decrease as the temperature decreases. With only the structures of the first and second conventional examples, the water vapor contained in the outside air enters from the breathing hole 21a and is partially liquefied mainly in the portion where the flow path direction changes, and this water content enters the passage 8a. Collect. The water accumulated in the passage 8a is a very small amount that spontaneously evaporates, but the water vapor flowing directly into the HDA is
Unless the device operates and the temperature inside the HDA rises, it is not discharged to the outside from the breathing hole 21a. Further, since the magnetic disk device can be easily carried by mounting the magnetic disk device in the notebook personal computer, the usage environment may be severe. For example, it may be assumed that the temperature is suddenly changed from a low temperature place to a warm place. In such a case, since the temperature of HDA is lower than that of the outside air, the HDA is suddenly brought into a warm place to cause dew condensation, and water drops adhere to the surface of the HDA. At this time, since the HDA inhales the outside air from the breathing hole 21a, air containing a lot of water droplets and water vapor adhering to the HDA surface may flow in from the breathing hole 21a, and this moisture may flow into the HDA.

Further, in forming the long and narrow passage 8a, it is difficult to secure a sufficient area because the device 17 is mounted at a high density. Therefore, as shown in the second conventional example or FIG. 8a and the passage 8a are likely to be adjacent to each other. Therefore, as the adhesive used to bond the moisture-proof sheet 33, an epoxy-based adhesive having a low moisture permeability cannot be applied. Therefore, a thin sheet-like adhesive having a relatively high moisture permeability and easy to process is used. Must be used. Therefore, as described above, what is liquefied and becomes water in the portion which flows in from the breathing hole 21a and whose flow path direction changes is the passage 8
There is a problem of permeating the inside of the adhesive forming a, reaching the adjacent passages 8a one after another to form a new bypass, and destroying the passage 8a structure for delaying the diffusion of water vapor into the HDA.

With respect to the amount of the hygroscopic agent 23a shown in FIG. 18, it is necessary to mount an amount that can absorb all the moisture flowing into the HDA by the end of the life of the magnetic disk device.
Have difficulty. This is because there is a limit to mounting in the HDA of a magnetic disk device which is required to be downsized. Therefore, in order to reduce the loading amount of the hygroscopic agent 23a, it is important to reduce the amount of water vapor flowing into the HDA.

In the case of a structure in which a magnetic disk device is mounted in a housing like a large computer, a fan (not shown) is provided as a cooling means for preventing a temperature rise in the housing. In addition to the cooling function, this fan has a problem that it also takes in atmospheric dust contained in the air at the same time by taking in air from the outside of the housing. Conventionally, FIG.
Since the external filter 22 is inside the HDA as shown in FIG.
Of the outside of the HDA becomes abnormally non-uniform, the outside air from the portion between the packing 28 and the base 7 or the cover 8 is relatively weakly shielded from the outside air. There is a risk of intrusion.

Regarding the adsorption of the gas generated in the HDA, there is an example described in the above-mentioned fourth conventional example. However, fixing a component such as the gas adsorbent 23b that does not particularly require mounting accuracy by using screws as in the related art has a problem in terms of assemblability and reduction of components.

As described above, according to the conventional technique, the magnetic disk device is miniaturized and thinned, the assembly is automated, the price is reduced,
There is no consideration for high reliability and the like, and there is a problem in the technology for keeping the humidity inside the HDA always low.

The present invention provides a magnetic disk device which is suitable for keeping the humidity in the HDA always low, which enables miniaturization and thinning of the magnetic disk device, automation of assembly, cost reduction and high reliability. The purpose is to do.

[0026]

A magnetic disk apparatus according to the present invention comprises a rotatable magnetic disk for recording information, a head for recording / reproducing information on / from the magnetic disk, and a carriage for fixing and moving the head. And a base and a cover for holding them and shutting them off from the outside air, a sealing seal for sealing a gap between the base and the cover, and a pressure between the inside and the outside air sealed from the outside air by the sealing seal. Having a head disk assembly with a breathing hole for adjusting the difference, particularly when outside air flows into the head disk assembly through a passage from the breathing hole into the head disk assembly, A member capable of absorbing moisture contained in the outside air and spontaneously evaporating water droplets due to dew condensation is provided near the breathing hole in the passage or on the side surface of the passage. It is characterized in that.

[0027]

In the vicinity of the breathing hole of the passage from the breathing hole to the HDA or on the side surface of the passage, a member capable of absorbing moisture when the outside air flows into the HDA and spontaneously evaporating water droplets due to dew condensation is provided. As a result, it is possible to prevent the phenomenon that the water vapor contained in the outside air flows in through the breathing holes and partly liquefies, mainly in the part where the flow path direction changes, and this water content accumulates in the passage. It is possible to suppress the inflow of water vapor into the. In addition, even if the surface of the magnetic disk device is condensed due to a severe temperature condition such as being transported from a low temperature place to a high temperature place rapidly, the water flowing in from the breathing hole is absorbed and the inside of the HDA is absorbed. There is no problem flowing into.

Therefore, for example, as shown in FIG.
In order to provide the passage 8a in a narrow area, even if the passage 8a has a curved structure and one passage 8a is close to the passage 8a, a bypass is formed in the passage 8a to delay the diffusion of water vapor into the HDA. It is possible to prevent the phenomenon that the structure of the passage 8a is destroyed.

Here, the water absorbed by the above-mentioned members evaporates spontaneously, and the magnetic disk device operates to raise the temperature of the HDA and heat the member in contact with the cover 8 to evaporate. Is increased and the air in the HDA is exhaled to the outside of the HDA through the passage 8a and out of the breathing hole 21a. That is, since the above member is provided near the breathing hole or on the side surface of the passage, the absorbed water can be easily discharged to the outside of the HDA. Therefore, according to the present invention, it is possible to reduce the amount of water vapor or water flowing into the HDA, thereby reducing the loading amount of the hygroscopic agent (for example, the hygroscopic agent 23a shown in FIG. 18) in the HDA. You can

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments shown in the accompanying drawings will be described below. FIG. 3 is a sectional view showing an example of a magnetic disk device to which the present invention is applied, and FIG. 4 is a top view of the same magnetic disk device in a cover open state.
The same parts as those of the conventional example shown in FIG.
HDA shown in FIGS. 3 and 4 corresponds to H shown in FIGS.
The difference from DA is the following part.

First, as shown in FIG. 3, the hermetically sealed connector 10 is formed on the lower surface of the read / write control board 12 (see FIG. 4) by using an epoxy adhesive having a low moisture permeability for the base 7. It is provided by adhesion, and is a point that the signal at the time of reading / writing of the head transmitted to the read / write control board 12 is transmitted to the outside of the HDA via the hermetically sealed connector 10. Here, the hermetically sealed connector 10 relays electrical signals between the inside and outside of the HDA, and a plurality of pins for transmitting signals and a molded portion for holding the pins are completely hermetically sealed. There is something. The current of the coil 9 is also transmitted to the sealed connector 10 (FIG. 2) through the FPC 14a (see FIG. 4). The hermetically sealed connector 10 is connected to a circuit board 11 (see FIG. 3) for controlling the magnetic disk device outside the HDA.

Secondly, the drive current of the spindle motor 6 is transmitted to the hermetically sealed connector 10 (FIG. 2) by the FPC 14b (see FIG. 4).

Thirdly, in order to seal the inside of the HDA from the outside air, aluminum is used as a material in a gap between the base 7 and the cover 8 so as not to allow moisture to pass through, and one side is sealed with an adhesive. This is the point where the seal 21 is attached (see FIG. 3).

FIG. 1 is an enlarged cross-sectional view of the breathing hole portion 20 shown in FIG. 3, and FIG. 2 is a top view of the breathing hole portion 20, similarly showing a passage 8 through which outside air flows from the breathing hole 21a into the HDA.
It shows a. That is, a breathing hole 21a is provided on the surface of the cover 8 on the outside of the HDA, and a passage 8a for suppressing the inflow of water vapor from the outside is provided. This passage 8
"a" is machined or molded. In the passage 8a, at the end where the flow direction of the outside air changes from the breathing hole 21a first, it is possible to absorb moisture and evaporate it naturally at a position as close to the breathing hole 21a as possible. An absorbent material 1 made of a resin (for example, sponge) or a chemical fiber that does not deteriorate until the life of the device is provided by adhesion or fitting. On the upper surface of the cover 8 located right below the breathing hole 21a, dust from the outside is exposed to the HDA.
An external filter 22 for preventing its invasion is placed, and a hermetically sealed seal 21 provided with a hole for a breathing hole 21 a is attached so as to cover the external filter 22. The external filter 22 is fixed by sticking the hermetic seal 21. At this time, in the absorbent 1 and the external filter 22, the magnetic disk device operates and the temperature inside the HDA rises, and the internal air pressure rises, so that the air inside the HDA passes from the passage 8a to the outside through the breathing hole 21a. It is necessary to arrange the passage 8a so as not to block it.

According to the structure shown in FIGS. 1 and 2, conventionally, water vapor contained in the outside air flows in from the breathing hole 21a, and a part thereof is liquefied mainly in the portion where the flow path direction changes, and this water content is The phenomenon accumulated in the passage 8a can be prevented by absorbing the moisture by providing the absorbent 1 at a portion where a part of the water vapor contained in the outside air is liquefied.

Further, even if the surface of the magnetic disk device 17 is condensed due to a severe temperature condition such that the magnetic disk device 17 is transported from a low temperature place to a high temperature place, moisture is absorbed by the absorber 1. Can solve the problem of flowing into the HDA.

FIG. 5 is an explanatory top view showing another example of the breathing hole portion 20 (FIG. 3). In FIG. 5, the passage 8a is provided in a narrow region, and the passage 8a is formed by a curved path so that the passages 8a are adjacent to each other. According to this embodiment, as in the prior art, water droplets penetrate inside the adhesive of the hermetic seal 21 (the hermetic seal 21 is omitted in FIG. 5) forming the passage 8a, or one after another. Permeates the passage 8a adjacent to the
The structure can be effectively prevented from being destroyed.

The water absorbed by the absorbent 1 in this way is naturally evaporated, and the magnetic disk device is operated to cause HDA.
Temperature rises, the absorbent 1 in contact with the cover 8 is heated and moisture evaporates, and the pressure inside the HDA rises, and the air inside the HDA is discharged to the outside from the breathing hole 21a through the passage 8a. Phenomenon that occurs, and the absorber 1 is the breathing hole
Since it is provided in the vicinity of a, it is easily discharged to the outside of the HDA.

Further, in the prior art, as shown in FIG. 17, both the HDA using the packing 28 and the HDA using the hermetic seal 21 have the passage 8a for suppressing the inflow of water vapor from the outside. The moisture-proof sheet 33 was provided on the. However, according to the structure of the embodiment shown in FIG. 1, the moisture-proof sheet 33 is also used in the hermetic seal 21, and the moisture-proof sheet 33 becomes unnecessary.

Further, as compared with the prior art shown in FIG.
The external filter 22 (FIG. 2) is provided at a position in contact with the breathing hole 21a. Therefore, as in the prior art, external dust is clogged in the passage 8a, the pressure difference between the outside and the inside of the HDA becomes abnormally uneven, and the outside air enters from a portion where the outside air is relatively weakly blocked. Does not occur.

Further, in the embodiment shown in FIGS. 1 to 5, the airtight seal 21 is used to seal the space between the base 7 and the cover 8, and like the structure using the packing 28, the humidity of the outside air is HDA. There is no problem of invading inside and generating harmful gas to HDA depending on the material.
The work management of the shrinkage allowance of the packing 28 due to the fastening is also unnecessary. Further, in the prior art, the structure in which the uniform load is applied to the entire surface of the packing 28 by fastening the cover screw 31 to the mating surface of the cover 8 and the base 7 via the packing 28, but the cover 8 is fixed to the base 7. Therefore, it is not necessary to provide a large number of cover screws 31 as in the prior art, and the number of cover screws 31 can be reduced.
In addition, after fixing the cover 8 to the base 7, the hermetic seal 2
All the work up to the attachment of 1 is the component mounting from the cover 8 side, and the assembly by the automatic machine is possible.

By blocking the water vapor entering from the outside of the HDA by the above structure, the loading amount of the hygroscopic agent 23a can be reduced as shown in FIG. In addition, the use of the hermetic seal 21 eliminates the generation of gas by the packing 28, and the amount of the gas adsorbent 23b mounted can be reduced.

FIG. 7 is a top view explanatory view showing another example of the breathing hole portion 20, and FIG. 8 is a sectional view of the breathing hole portion 20. In the embodiment shown in FIGS. 7 and 8, in order to effectively suppress the inflow of water vapor and harmful gas into the HDA, the gas adsorption is performed in the passage 8a from the breathing hole 21a to the HDA or at the end of the passage 8a. The agent 23b and the hygroscopic agent 23a are provided.

In this case, since the hygroscopic agent 23a has a property of lowering the ability to absorb moisture due to the adsorption of gas, the outside air passes through the passage 8a, and first, the gas adsorbent 23a.
It is better to arrange the hygroscopic agent 23a after passing through the vicinity of b. Further, some of the materials of the hygroscopic agent 23a and the gas adsorbent 23b generate dust, and in order to fix the positions of the hygroscopic agent 23a and the gas adsorbent 23b, the materials of the external filter 22 and the internal filter 13 are fixed. The filter medium 34 used in the above is provided as shown in FIG.

FIG. 9 is a top view explanatory view showing another example of the breathing hole portion 20, and FIG. 10 is a sectional view of the breathing hole portion 20. In the embodiment shown in FIGS. 9 and 10, only the passage 8a portion shown in FIGS. 7 and 8 is integrally molded with a material that does not allow moisture to pass through, such as aluminum or a resin, to form the case 24,
The case 24 is provided with the absorbent 1, the hygroscopic agent 23a and the gas adsorbent 23b (hereinafter, this structure is referred to as a passage assembly). The shape of the passage 8a is different from that of the base 7 or the cover 8. Since it is thin and long so that it can not be seen in the part (depth and width are about 0.5 mm, length is about 50 mm), it is conventionally machined to provide the base 7 or the cover 8. In the case of providing or molding with a precision mold, it was necessary to use a split mold in which another precision piece was used only for the passage 8a. However, with the passage assembly shown in FIGS. 9 and 10, the passage 8a
Can be made as one part separate from the base 7 or the cover 8, and the passage 8a part which has conventionally been required to be machined or precision-molded in the base 7 or the cover 8 is separated. As a result, the base 7 or the cover 8 includes a mold structure and is easy to manufacture. In addition, by using one large passage assembly, assembly by an automatic machine becomes easy. When the above-mentioned passage assembly is supplied as one component, since it is provided with the absorbent material 1, the hygroscopic agent 23a, and the gas adsorbent 23b, it is necessary to package it so that dust and moisture cannot pass through.

When the passage assembly is inserted into the cover 8, the cover 8 is provided with through holes having the dimensions D and E of the passage assembly shown in FIG. 9, and the passage assembly is inserted therein.
The passage assembly is provided with a collar portion 23c (see FIG. 10) so that the cover 8 can be mounted after being fixed to the base 7 and that the fixing is sure. Next, the external filter 22 is placed and fixed by sticking the hermetic seal 21 (see FIG. 8).

FIG. 11 is a top view explanatory view showing another example of the breathing hole portion 20, in which the shape of the passage 8a is spiral. According to this shape, the passage 8a can be secured in the narrowest area. In this embodiment, the absorbent 1 is arranged outside the spiral passage 8a, but the present invention is not limited to this, and may be arranged in a part of the circumference such as inside the spiral passage 8a. Alternatively, it may be arranged only near the breathing hole 21a.

FIG. 12 is a sectional view showing another example of the breathing hole portion 20. In FIG. 12, relatively light parts such as the hygroscopic agent 23 a and the gas adsorbent 23 b are provided in the cover 8 having through holes, inserted therein, and fixed by the hermetic seal 21. In order to fix the cover 8 to the base 7 before mounting and to ensure the fixing, the collar portion 23c
Is provided. In the embodiment shown in FIG. 12, the area of the component to be attached is large, and in order to prevent it from being accidentally pushed in from above the hermetic seal 21 by a finger or the like, a plate 26 made of a material such as thin stainless steel plate is used. Part 23
The same shape as c may be provided between the component and the hermetic seal 21.

According to the embodiment shown in FIG. 12, it is not necessary to provide a fixing member such as screws, which is required in the prior art. Also, assembly by an automatic machine becomes easy.

FIG. 13 shows a cover 8 on the base 7 shown in FIG.
It is an example of the structure which fixes, and is a sectional view of the state which attached the airtight seal 21. To seal the gap between the base 7 and the cover 8, the hermetic seal 21 is provided on the outer periphery of the base 7 and the cover 8.
It is necessary to securely bond the periphery of the breathing hole 21a and the periphery of the passage 8a, so that these parts are made higher than other surfaces. In this embodiment, in the areas A, B and C,
It is composed higher than other aspects.

According to the above-described embodiment, when the sealing seal 21 is attached, the entire upper surface of the sealing seal 21 is pressed against the outer periphery of the base 7, the breathing hole 21a of the cover 8 and the passage 8a. Since the HDA is concentrated, the hermeticity of the HDA is not impaired due to defective work, and assembly by an automatic machine becomes easy.

FIG. 14 is a top view of the embodiment shown in FIGS. 3 and 4, in which the seal number 21 is pasted and then the serial number and the bar code are printed on the seal number 21. In this case, a material suitable for printing may be stuck to the printing surface of the hermetic seal 21, but it is also possible to print with immortal ink on the aluminum plate.

The above embodiment eliminates the need for a sheet (see sheet 32 in FIG. 21) on one side of which a conventional printable sheet material is applied with an adhesive.

FIG. 15 is a sectional explanatory view showing a structure in which a surface where the base 7 and the cover 8 contact each other is provided in the side surface of the HDA, unlike the structure in which the cover 8 is fixed to the base 7 in FIG. With the downsizing of the magnetic disk device, the base 7 and the cover 8 can be fixed only by the band-shaped hermetic seal 21 as shown in FIG. In this case, in order to ensure the tight sealing of the end portion of the hermetically sealed seal 21 applied first,
As shown in FIG. 16, the end shape of the hermetic seal 21 is widened. That is, the width of the overlapping portion at the end portion of the hermetic seal 21 is made wider than the width of the end portion attached at the beginning.

In addition to the gap between the cover 8 and the base 7, it is desirable to seal all the places communicating with the HDA, such as the screw portion, with the same moisture impermeable material as the hermetic seal 21.

According to the hermetic seal 21 of the above-mentioned embodiment, a complete hermetic seal between the base 7 and the cover 8 can be achieved in the magnetic disk device. Further, the cover screw 31 for fixing the cover 8 to the base 7 becomes unnecessary.

In the above-described embodiment, the breathing portion 20 is provided with the hygroscopic agent 23a and the gas adsorbent 23b, but the present invention is not limited to this, and only one of them is provided. It may be configured as follows.

As described above, it is possible to provide a magnetic disk device suitable for keeping the inside of the HDA at a low humidity all the time, because further miniaturization and thinning, automation of assembly, cost reduction and high reliability can be achieved.

[0059]

According to the present invention, it is possible to provide a magnetic disk device suitable for keeping the humidity inside the head disk assembly always low.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of a breathing hole portion shown in FIG.

FIG. 2 is an explanatory top view showing an enlarged breathing hole portion shown in FIG.

FIG. 3 is a sectional view showing an example of a magnetic disk device to which the present invention is applied.

FIG. 4 is a top view of the magnetic disk device shown in FIG. 3 with a cover open.

5 is an explanatory top view showing another example of the breathing hole portion shown in FIG.

FIG. 6 is a diagram showing the relationship between the HDA internal volume and the amount of loaded hygroscopic agent.

FIG. 7 is an explanatory top view showing another example of the breathing hole portion shown in FIG.

8 is a cross-sectional view of the breathing hole portion shown in FIG.

9 is a top view explanatory diagram showing another example of the breathing hole portion shown in FIG. 3. FIG.

10 is a cross-sectional view of the breathing hole portion shown in FIG.

11 is an explanatory view of a top view showing another example of the breathing hole portion shown in FIG.

12 is a cross-sectional view of the breathing hole portion shown in FIG.

13 is an example of a structure for fixing a cover to the base shown in FIG. 3, which is a cross-sectional view in a state in which a hermetic seal is attached.

14 is a top view of the embodiment shown in FIGS. 3 and 4. FIG.

FIG. 15 is a sectional explanatory view showing an example of a magnetic disk device to which the present invention is applied.

FIG. 16 is a plan view showing an example of a hermetic seal.

FIG. 17 is a sectional view showing a conventional magnetic disk device.

FIG. 18 is a top view of the conventional magnetic disk device with the cover opened.

19 is a cross-sectional view showing an example of the breathing hole portion shown in FIG.

20 is an explanatory top view showing a breathing hole and a passage shown in FIG. 19. FIG.

FIG. 21 is a top view of a conventional magnetic disk device.

[Explanation of symbols]

1 ... Absorbing material, 2 ... Voice coil motor, 2a ... Magnet, 2b ... Yoke, 3 ... Carriage, 4 ... Head, 5 ...
Disk, 6 ... Spindle motor, 7 ... Base, 8 ... Cover, 8a ... Passage, 9 ... Coil, 10 ... Sealed connector, 11 ... Circuit board, 12 ... Read / write control board, 3
… Internal filter, 14a… FPC (CARRIAG
E), 14b ... FPC (MOTOR), 16 ... Stopper, 17 ... Device, 18 ... Notebook type personal computer, 19
… Equipment control board, 20… Large computer, 2
DESCRIPTION OF SYMBOLS 1 ... Airtight seal, 21a ... Breathing hole, 22 ... External filter, 23a ... Hygroscopic agent, 23b ... Gas adsorbent, 23c ... Collar part, 24 ... Case, 26 ... Plate, 27 ... Printing part,
28 ... Packing, 29 ... FPC (OUT), 31 ... Cover screw, 32 ... Sheet, 33 ... Moisture-proof sheet, 34 ... Filter filter material.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshio Matsushita 2880, Kozu, Odawara, Kanagawa Stock Company Hitachi Storage Systems Division (72) Nobuyuki Okunaga 2880, Kozu, Odawara, Kanagawa Hitachi, Ltd. Storage System Division (72) Inventor Shoro Takatsuka 2880 Kokuzu, Odawara-shi, Kanagawa Hitachi Ltd. Storage System Division

Claims (1)

[Claims] 1. A rotatable magnetic disk for recording information, a head for recording / reproducing information on / from the magnetic disk, a carriage for fixing and moving the head, and a carriage for holding these and keeping them from the outside air. A base and a cover for shutting off, a hermetic seal for hermetically sealing the gap between the base and the cover, and a breathing hole for adjusting the pressure difference between the inside and the outside air sealed by the above-mentioned hermetic seal In a magnetic disk device having a head disk assembly, when the outside air flows into the head disk assembly through a passage from the breathing hole into the head disk assembly, it absorbs moisture contained in the outside air, and A member capable of spontaneously evaporating water droplets due to inflowing dew condensation or water droplets due to dew condensation generated in the passage is provided near the breathing hole in the passage or A magnetic disk device, characterized in that provided on the passage side.