JP3732461B2 - Magnetic disk unit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a magnetic disk device including a respiratory filter unit.
[0002]
In recent years, magnetic disk devices, which are a type of external storage device for computers, have been reduced in size and thickness, and further reduction in power consumption has been demanded. Technological advances related to magnetic heads and magnetic disks are also remarkable. As a result of pursuing higher efficiency and performance, the flying height of the head is reduced, and the magnetic heads and magnetic disks are easily affected by metal corrosive gas.
[0003]
[Prior art]
In a magnetic disk device for a computer, a contact start stop (CSS) is generally adopted. In the CSS, during the rotation of the magnetic disk, the head floats on the magnetic disk at a minute interval by a balance between the flying force of the air fluid generated by the high-speed rotation and the force of the spring arm that presses the head against the disk.
[0004]
When the rotation of the magnetic disk stops, the head moves to a contactable area on the disk, where the head and the disk come into contact. While the disk is stopped rotating, the head and the disk remain in contact.
[0005]
As described above, while the magnetic disk is rotating, the head flies over the magnetic disk with a small interval, and thus a head crash occurs due to slight dust or the like. For this reason, the magnetic disk and the head actuator are arranged in a sealed disk enclosure (housing).
[0006]
However, it is difficult to maintain the hermeticity inside the housing for a long period of time, and the flying height of the magnetic head changes due to pressure fluctuations inside the apparatus due to temperature changes or the like. In order to prevent this, a breathing hole is provided in the housing so that the pressure inside and outside the apparatus is approximately equal.
[0007]
A breathing filter is usually attached to the breathing hole, and this breathing filter prevents dust from entering the inside from the outside of the apparatus.
[0008]
[Problems to be solved by the invention]
However, although this type of breathing filter has a function of removing dust, it cannot prevent metal corrosive gas from entering the apparatus.
[0009]
Accordingly, an object of the present invention is to provide a magnetic disk device having a simple configuration capable of preventing dust and metal corrosive gas from entering the inside of the device.
[0010]
[Means for Solving the Problems]
According to the present invention, a magnetic disk and a magnetic head for recording / reproducing information facing the magnetic disk are accommodated in a substantially airtight manner therein, a housing having a breathing hole, and a housing facing the breathing hole. attached, attached to the housing so as to close the unit cover having a first small hole for communicating the first when the expansion chamber to image formation and both the first expansion chamber and the outside with the housing, the breathing hole A second expansion chamber that communicates with the first expansion chamber via the breathing hole and a second expansion chamber that communicates with the second expansion chamber and the interior of the housing. comprising a unit wall which is integrally formed with the housing having a small hole, and a second filter mounted on the unit-wall so as to close said second small hole, the housing includes an upper Has a thin portion breathing hole is formed, a magnetic disk device, characterized in that the first expansion chamber is enlarged is provided by the thin-walled portion.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0013]
FIG. 1 is a partial sectional plan view of a magnetic disk apparatus to which the present invention is applied. This magnetic disk device supports a plurality of magnetic disks 2, a plurality of magnetic heads 4 that record and reproduce information on the magnetic disk 2, and supports the magnetic head 4 between tracks on the magnetic disk 2. A rotary head actuator 6 to be moved is provided in the housing 8. Reference numeral 10 represents a cover for sealing the housing 8.
[0014]
The head actuator 6 includes a carriage 16 attached to a shaft 12 via a bearing 14. The carriage 16 is provided with a main body portion 18 provided to be rotatable with respect to the shaft 12, and substantially from the main body portion 18 to the shaft 12. The arm portion 20 extends vertically.
[0015]
The magnetic head 4 is attached to the tip of the arm portion 20 via a spring arm 22, and the magnetic head 4 is pressed against the magnetic disk 2 when the magnetic disk 2 is stopped by the elastic restoring force of the spring arm 22. Yes. Further, during the rotation of the magnetic disk 2, the magnetic head 4 floats at a position where the flying force generated by the air flow between the magnetic head 4 and the magnetic disk 2 balances with the elastic force of the spring arm 22. .
[0016]
A support member 24 is provided on the opposite side of the carriage body 18 to the arm 20. A coil 26 is fixed to the outer peripheral edge of the support member 24 by adhesion, for example. Permanent magnets 28 and 30 for generating a magnetic field for obtaining a driving force of the head actuator 6 by interaction with a current flowing through the coil 26 are provided on the outer side and the inner side of the coil 26, respectively.
[0017]
Reference numeral 32 denotes a yoke for forming a magnetic circuit including the permanent magnets 28 and 30. This magnetic circuit generates a radial magnetic flux between the permanent magnets 28 and 30, and a winding portion parallel to the axis 12 of the coil 26 intersects with this magnetic flux to generate a driving force for the head actuator 6.
[0018]
Reference numeral 34 represents a respiratory filter unit characteristic of the present invention, and this respiratory filter unit 34 is detachably attached to the housing 8, for example. Various variations of the structure of the respiratory filter unit 34 will be described later.
[0019]
FIG. 2 is a cross-sectional view of a breathing filter unit mounting portion in the magnetic disk apparatus of FIG. A thin portion 8A is formed in the housing 8, and a breathing hole 36 is formed in the thin portion 8A. The diameter of the breathing hole 36 is 1 mm, for example.
[0020]
The breathing filter unit 34 is attached to the housing 8 so as to face the breathing hole 36.
[0021]
A dust filter 38 is provided between the respiratory filter unit 34 and the housing 8. The dust filter 38 is for preventing the passage of dust through the breathing hole 36. The dust filter 38 is attached to the thin housing portion 8A, for example.
[0022]
The reason why the dust filter 38 is directly attached to the housing 8 in this way is to enable replacement of the respiratory filter unit 34 under a general environment. That is, when the breathing filter unit 34 is removed from the housing 8 under a general environment, dust is infiltrated from the outside to the inside by attaching the dust filter 38 directly to the thin portion 8A as in the present embodiment. This is prevented.
[0023]
FIG. 3A is a plan view showing a first embodiment of the respiratory filter unit, and FIG. 3B is a sectional view of the respiratory filter unit taken along line (B)-(B) in FIG. .
[0024]
The respiratory filter unit 34 has a substantially cylindrical unit body 40 closed at the bottom on the housing side. A thick portion 40A is formed at the bottom of the unit body 40, and a first small hole 42 is formed at the approximate center of the thick portion 40A.
[0025]
Reference numeral 44 denotes a unit cover that defines the expansion chamber 48 together with the unit body 40, and this unit cover 44 is seated on the top of the unit body 40. A second small hole 46 having substantially the same diameter as the first small hole 42 is formed in the approximate center of the unit cover 44.
[0026]
When the pressure inside the apparatus increases due to the start of the spindle motor for rotating the disk or the heat generated by the magnetic disk apparatus, the air inside the apparatus enters the expansion chamber 48 through the first small hole 42, where Will stay.
[0027]
On the other hand, when the pressure inside the apparatus decreases due to the stop of the spindle motor or due to the temperature drop of the magnetic disk apparatus, the air staying in the expansion chamber 48 is introduced into the apparatus.
[0028]
As described above, according to this embodiment, there is no possibility that the metal corrosive gas outside the apparatus enters the apparatus due to the pressure difference between the inside and outside of the apparatus. Further, in a steady state where there is no pressure difference inside and outside the apparatus, the metal corrosive gas outside the apparatus can enter the expansion chamber 48 only by diffusion through the second small hole 46. Is small and has no adverse effect.
[0029]
FIG. 4 is a sectional view showing a second embodiment of the respiratory filter unit. In this embodiment, the respiratory filter unit 34 divides the expansion chamber defined by the unit body 40 and the unit cover 44 into two parts (a first expansion chamber 48A and a second expansion chamber 48B). It is characterized by further comprising.
[0030]
A third small hole 52 having substantially the same diameter as the first and second small holes 42 and 46 is formed in the approximate center of the unit wall 50.
[0031]
According to this embodiment, since the expansion chamber is divided into two parts, entry into the apparatus due to diffusion of metal corrosive gas from the outside in a steady state is less likely to occur. In order to make this effect more prominent, the expansion chamber may be divided into three or more portions.
[0032]
If the diameter of each small hole 42, 46, 52 is 0.5 mm or less, it is difficult to form a small hole by machining. On the other hand, if it is 1 mm or more, there is a concern about diffusion of metal corrosive gas. The hole diameter is preferably in the range of 0.5 mm to 1.0 mm.
[0033]
The thick part 40A is formed at the bottom of the unit body 40 in order to satisfactorily prevent the metal corrosive gas from entering the apparatus due to diffusion by making the first small hole 42 sufficiently long. .
[0034]
FIG. 5 is a sectional view showing a third embodiment of the respiratory filter unit. This embodiment is characterized in that it further includes a desiccant 54 and a gas filter 56 provided in the first and second expansion chambers 48A and 48B, respectively, in contrast to the second embodiment of FIG. .
[0035]
The gas filter 56 is for absorbing metal corrosive gas from the outside of the apparatus. The desiccant 54 is for removing moisture (water vapor) contained in the inflow air from the outside of the apparatus.
[0036]
The desiccant 54 is, for example, silica gel, and the gas filter 56 includes, for example, activated carbon as its main component.
[0037]
According to this embodiment, even if air flows in from the outside of the apparatus, moisture and metal corrosive gas contained in the air can be removed, which greatly contributes to prevention of head crash.
[0038]
In the present embodiment, the desiccant 54 is provided in the first expansion chamber 48A on the outside of the apparatus in comparison with the case where the gas filter is provided in the first expansion chamber 48A. This is because the lifespan of the product is extended.
[0039]
FIG. 6 is a sectional view showing a fourth embodiment of the respiratory filter unit. In this embodiment, a first gas filter 56 ′ and a second gas filter 56 are provided in the first expansion chamber 48A and the second expansion chamber 48B, respectively. The second gas filter 56 corresponds to the gas filter 56 in the third embodiment of FIG.
[0040]
The gas filters 56 and 56 'absorb a different kind of metal corrosive gas. For example, the gas filter 56 absorbs carbon dioxide well, and the gas filter 56 ′ absorbs sulfurous acid gas well.
[0041]
FIG. 7A is a plan view showing a fifth embodiment of the respiratory filter unit, and FIG. 7B is a sectional view of the respiratory filter unit taken along line (B)-(B) in FIG. .
[0042]
This embodiment is characterized in that the first, second and third small holes 42, 46 and 52 are not arranged in a straight line as compared with the second embodiment of FIG. That is, the small holes are arranged so as not to overlap each other. Although not shown, the breathing hole 36 (see FIG. 2) of the housing is also arranged so as not to overlap each small hole.
[0043]
By doing so, the air inflow path from the outside of the apparatus to the inside can be lengthened, so that the metal corrosive gas and moisture are less likely to enter the inside from the outside of the apparatus.
[0044]
In the embodiment described above, the respiratory filter unit is provided separately from the housing, but a part of the respiratory filter unit may be formed integrally with the housing. A specific example will be described with reference to FIGS.
[0045]
FIG. 8 is a cross-sectional view of the vicinity of the breathing hole of the magnetic disk device in which a part of the breathing filter unit is formed integrally with the housing. A thin portion 8A is formed in the housing 8, and a breathing hole 36 is formed in the thin portion 8A. A thin portion 8B that is thicker than the thin portion 8A and thinner than portions other than the thin portion 8A of the housing 8 is formed around the thin portion 8A.
[0046]
A filter 58 is provided in the thin portion 8A so as to face the breathing hole 36. For example, the filter 58 has a function of blocking the passage of dust, and the filter 58 may further have a function of blocking the passage of metal corrosive gas.
[0047]
Opposite to the filter 58, the housing 8 is provided with a unit cover 60 for defining the first expansion chamber 64 together with the housing 8. The unit cover 60 has a small hole 62 that communicates the first expansion chamber 64 with the outside of the housing.
[0048]
Also according to the present embodiment, it is possible to provide a magnetic disk device having a simple configuration that can prevent dust and metal corrosive gas from entering the inside of the device in accordance with the same principle as the above-described embodiment.
[0049]
FIG. 9 is another cross-sectional view of the vicinity of the breathing hole of the magnetic disk device in which a part of the breathing filter unit is formed integrally with the housing. In this embodiment, in order to form the second expansion chamber 65 inside the housing 8, a unit wall 66 is formed integrally with the housing 8, for example. A thin wall 66A is formed in the unit wall 66, and a small hole 68 is formed in the thin wall 66A.
[0050]
The small hole 68 communicates the second expansion chamber 65 and the inside of the housing, and the breathing hole 36 communicates the first expansion chamber 64 and the second expansion chamber 65.
[0051]
A filter 70 is provided in the thin portion 66 </ b> A of the unit wall 66 so as to face the small hole 68. The filter 70 has the same function as the filter 58.
[0052]
The second expansion chamber 65 is filled with a gas adsorbent or a desiccant 72. Reference numeral 74 represents a lid that can be opened and closed for exchanging the gas adsorbent or desiccant 72 from the outside of the housing. The lid 74 is, for example, a screw lid, and thereby the hermeticity of the second expansion chamber 65 is ensured.
[0053]
According to this embodiment, since there is one more expansion chamber as compared with the previous embodiment, the tolerance of the apparatus to the metal corrosive gas is improved. Further, as shown in the drawing, the desired function can be sufficiently exhibited by filling the second expansion chamber 65 with a gas adsorbent or a desiccant 72 as necessary.
[0054]
The embodiment described with reference to FIGS. 8 and 9 can further simplify the configuration of the apparatus as compared with the embodiment having the breathing filter unit separately from the housing. The place that contributes to the conversion is great.
[0055]
【The invention's effect】
As described above, according to the present invention, there is an effect that it is possible to provide a magnetic disk device having a simple configuration capable of preventing dust and metal corrosive gas from entering the inside of the device.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional plan view of a magnetic disk apparatus to which the present invention can be applied.
2 is a cross-sectional view of a breathing filter unit mounting portion of the magnetic disk device of FIG. 1. FIG.
FIG. 3 is a diagram showing a first embodiment of a respiratory filter unit.
FIG. 4 is a diagram showing a second embodiment of the respiratory filter unit.
FIG. 5 is a view showing a third embodiment of the respiratory filter unit.
FIG. 6 is a diagram showing a fourth embodiment of the respiratory filter unit.
FIG. 7 is a diagram showing a fifth embodiment of the respiratory filter unit.
FIG. 8 is a cross-sectional view of the vicinity of the breathing hole of the magnetic disk device in which a part of the breathing filter unit is formed integrally with the housing.
FIG. 9 is another cross-sectional view of the vicinity of the breathing hole of the magnetic disk device in which a part of the breathing filter unit is formed integrally with the housing.
[Explanation of symbols]
2 Magnetic disk 4 Magnetic head 8 Housing 34 Breathing filter unit 36 Breathing hole 40 Unit body 42 First small hole 44 Unit cover 46 Second small hole 48 Expansion chamber

Claims (2)

A magnetic disk and a magnetic head for recording / reproducing information facing the magnetic disk, which is housed in a substantially airtight manner and having a breathing hole;
It mounted on the housing opposite to the ventilation hole, and a unit cover having a first small hole for communicating the first when the expansion chamber to image formation and both the first expansion chamber and the outside with the housing,
A first filter attached to the housing to close the breathing hole ;
Defining a second expansion chamber communicating with the first expansion chamber via the breathing hole, and having the second small hole communicating the second expansion chamber and the interior of the housing; An integrally formed unit wall;
A second filter attached to the unit wall so as to close the second small hole ,
The housing has a thin portion in which the breathing hole is formed, a magnetic disk device, characterized in that the first expansion chamber is enlarged by the thin-walled portion. 2. The magnetic disk apparatus according to claim 1 , further comprising a gas adsorbent or a desiccant filled in the second expansion chamber .

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