JP2000331458A - Hermetic hard disk drive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an HDD which enables stable starting and rotating of a spindle motor without the occurrence of dew condensation in a dynamic pressure bearing part by a humidity change, temperature change, etc. SOLUTION: The HDD is housed in a perfectly hermetic housing casing which has hermeticity and completely shuts off the going and coming of air from and to the outside. At the time of hermetic sealing, an atmosphere of low humidity is maintained in the HDD housing case 23, more preferably the atmosphere below 0.1 atm in the steam pressure at 1 atm or gas, such as gaseous nitrogen, free of moisture is substituted for the air and is sealed therein. The perfectly hermetic type using a highly thick or highly rigid material is used for the HDD case 23 usable even in a reduced pressure state. The ordinary case which deals with the atmospheric pressure/temperature changes of the outdoor air is composed of the mechanism which is arranged with a member composed of an elastic body, such as bellows 25, and deformable by accompanying the atmospheric pressure change of the outside and allows the atmospheric pressure within the housing case 23 to follow up the outside, by which the size increase and weight increase of the case may be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a hard disk drive (hereinafter, referred to as an HDD) used as a small storage device of a computer.

[0002]

2. Description of the Related Art An example of a conventional HDD is shown in FIG.
Shown in In the figure, reference numeral 1 denotes a housing, and 2 denotes a cover which covers the housing 2, and both of them constitute a case (container) 3 for housing the HDD. Inside the HDD case 3 is housed an HDD having five disk units and six head units 6 as main components. FIG.
FIG. 3 is a cross-sectional view showing a detailed example of a disk unit 5 which is one of the main parts. In the figure, reference numeral 30 denotes a spindle motor for rotating a disk, and a plurality of disks serving as information media are provided on the outer periphery of the spindle motor 30. Will be installed.
As the components of the spindle motor 30, reference numeral 31 denotes a housing, 32 denotes a shaft fixed to the housing 31, and 33 rotors are fitted around the outer periphery of the shaft 32. On the outer periphery of the shaft 32, there are 34 stators,
35 rotor magnets are attached to the inner periphery of the rotor 33 facing the rotor magnet, respectively.

[0003] The operation of the disk unit thus configured is such that a rotating drive force is generated between the stator 34 and the rotor magnet 35 by energizing a coil wound around the stator 34 constituting the spindle motor 30. In this example, the rotor 33 rotates with respect to the shaft 32. Such rotation of the spindle motor 30 causes a plurality of disks to be rotated on the outer periphery of the rotor 33 as a component thereof.

Here, a dynamic pressure bearing is used for the spindle motor 30. Specifically, a radial dynamic pressure generating section 36, 3 is provided between the outer circumference of the shaft 32 and the inner circumference of the rotor 33.
7 are mounted at positions facing each other, and generate radial dynamic pressure by relative rotation between the two. Further, thrust dynamic pressure generating portions 38 and 39 are provided between the housing 31 and the rotor 33, respectively. A groove for generating a thrust dynamic pressure is formed on one of the two surfaces, and the thrust dynamic pressure is generated by rotating the rotor 33 in the same manner. This allows rotation of contact.

Returning to FIG. 3, a head assembly 7, which is a component of the head unit 6, is inserted into each of the rotating disk units 5 for each disk. It accesses the necessary part of the disk and retrieves or writes information.

The HDD constructed as described above is housed in the housing 1 shown in FIG. 3, and a cover 2 is put on the housing 1 and screwed. The inside of the case 3 is connected to the outside air through nine windows provided on the side surface of the housing 1 shown in the figure. The ten filters attached to the windows 9 prevent dust and the like from entering the inside. , The spindle motor 30 and other precision machine elements are protected.

[0007]

However, in the conventional HDD case 3 according to the above-described configuration, since the inside of the case 3 communicates with the outside air through the filter 20, the humidity of the outside air increases, Alternatively, when a rapid temperature change occurs, the dynamic pressure generating units 36 and 37 and / or 38 and 39 mounted on the spindle motor 30 provided therein.
Condensation may occur between the two. These dynamic pressure generating parts are in contact at rest, and even during rotation, the clearance between them is about several microns, and when the dew condensation occurs, the spindle motor cannot be started,
Alternatively, even when the motor is started, the rotation sometimes varies.

Also, the HDD case 3 according to the prior art
In this case, since the fluid is communicated with the outside air through the filter 10, when the external environment is in a depressurized state, it is not possible to generate a sufficient gas dynamic pressure in the dynamic pressure generating portion, and therefore, the bearing portion is not in contact with the external pressure. However, there may be problems such as the occurrence of a rotation failure due to rotation while the bearing is being rotated, or an increase in the rotational speed at which the bearing floats to a non-contact state, causing wear on the bearing portion.

Therefore, an object of the present invention is to change humidity,
It is an object of the present invention to provide an HDD that enables stable start-up and rotation without dew formation in the HDD case 3 even when there is a temperature change. It is still another object of the present invention to provide an HDD including a dynamic pressure bearing capable of obtaining stable rotation even when the external environment is in a reduced pressure state.

[0010]

SUMMARY OF THE INVENTION The present invention provides a hydrodynamic bearing which is sealed off from the outside air and preferably reduces or eliminates the moisture content of the gas sealed therein. This solves the above problem, and specifically includes the following contents.

According to a first aspect of the present invention, in the hard disk drive having a dynamic pressure bearing portion, at least the dynamic pressure bearing portion is sealed off from outside air.

According to a second aspect of the present invention, in a hard disk drive having a dynamic pressure bearing portion, a hard disk comprising a disk portion including the dynamic pressure bearing portion and a head portion for reading / writing information from / to the disk portion. The drive mechanism is characterized in that the drive mechanism is sealed off from the outside air.

According to a third aspect of the present invention, in the hard disk drive according to the present invention, a part of the case in contact with the outside air is made of a stretchable elastic body to reduce a pressure difference between the outside air and the inside of the case. It is characterized by.

A hard disk drive according to a fourth aspect of the present invention is characterized in that the elastic body having elasticity is a bellows.

According to a fifth aspect of the present invention, in the hard disk drive according to the present invention, the inside of the case, which is cut off from the outside air, has an atmosphere in which the vapor pressure at 1 atm of the gas inside the case is 0.1 atm or less. Features that have.

A hard disk drive according to a sixth aspect of the present invention is characterized in that air inside the case, which is isolated from outside air, is replaced with another gas.

The hard disk drive according to the present invention is characterized in that the other gas is a nitrogen gas.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An HDD according to a first embodiment of the present invention will be described with reference to the drawings. FIG.
In the HDD according to the present embodiment, in the figure, 11 is a housing, 12 is a cover that covers the housing 11,
Both form the HDD case 13. The housing 1
No. 1 does not provide a window portion that communicates with the outside air as in the prior art, and furthermore, a material or a material in which the entire case exhibits sufficient strength to withstand a predetermined internal and external pressure difference according to the purpose. It is composed of thick. Therefore, at the time of use, the cover 12 is fixed to the housing 11 with a plurality of screws, so that both are sealed and the HDD case 13 is shut off from the outside air. The HDD internal mechanism to be accommodated in the HDD case 13 includes a disk unit 5 and a head unit 6.
However, since the content is exactly the same as that of the above-described conventional technology, the details are omitted.

By configuring the HDD case 13 as described above, the internal mechanism of the HDD including the dynamic pressure bearing is completely shut off from the outside air, so that even if the humidity of the outside air increases, the inside of the HDD case is not affected. Therefore, it is possible to avoid adverse effects on the dynamic pressure bearing portion of the spindle motor due to dew condensation.

At this time, if the air in the outside air is used as it is as the gas sealed in the HDD case 13, depending on the water composition contained therein, if there is a sudden temperature change in the surroundings, the HDD case 13 It is conceivable that the water vapor pressure in the inside rises and causes dew condensation. Therefore, when the HDD case 13 is hermetically sealed, it is preferable that air having a reduced water content is sealed in advance or replaced with another gas such as an inert gas. This makes it possible to always keep the surroundings of the air bearing at a low humidity, thereby avoiding the occurrence of dew condensation. The degree of reduction of the water content may vary depending on the purpose of use, but for example, when considering use at about 0 ° C.,
It is preferable to provide an atmosphere in which the water vapor pressure at 1 atm is 0.1 atm or less. As the inert gas, nitrogen gas is preferable because it is easily available and inexpensive, but other inert gas such as argon gas and helium gas may be used. Further, any other gas may be used as long as it does not contain moisture and does not adversely affect the storage device.

Further, by configuring the HDD case 13 as described above, even when the outside air is in a decompressed state or extremely in a vacuum state, the inside of the HDD case 13 is filled with a gas of a predetermined pressure. Therefore, the gas required to generate dynamic pressure in the dynamic pressure bearing portion is secured, and H
The function as the DD is not hindered.

Next, an HDD according to a second embodiment of the present invention will be described with reference to the drawings. FIG. 2 shows an HDD according to the present embodiment. In the drawing, 21 is a housing, 22 is a cover for covering the housing 21, and both of them constitute an HDD case 23. In use, the cover 22 is fixed to the housing 21 with a plurality of screws, so that both are sealed, and the HDD case 23 is shut off from the outside air. Further, in the present embodiment, the housing 21 is provided with a window 24, and the window 24 is provided with a bellows-shaped elastic shielding portion 25, whereby the case 23 is firstly shielded from outside air. Is different from the embodiment of
In FIG. 2, the internal mechanism to be housed in the HDD case 23 is completely the same as that in FIG.

In the first embodiment, since the inside of the HDD case 13 is completely sealed from the outside air, there is an advantage that the air bearing function inside the case can be ensured even in an extremely reduced pressure state. In order to prevent the deformation of the HDD case 13 due to the difference and the adverse effect on the internal devices due to the difference, the housing 11 and the cover 12 constituting the case 13 need to have a certain rigidity. The use of rigid metal materials tends to increase the overall size and weight.

In the present embodiment, as a result of the provision of the bellows-shaped shielding portion 25, the bellows is deformed in accordance with a change in the outside air pressure, so that the pressure inside the storage case 23 can follow the outside, and Since the pressure difference between the inside and outside of the case can be reduced, the deformation of the storage case can be suppressed. Therefore, by adopting such a configuration, it is possible to avoid deformation affecting the internal devices without unnecessarily increasing the rigidity of the case constituent members, and it is one of the objects of the present invention to prevent the HDD from starting due to dew condensation, Alternatively, functional deterioration can be prevented.

The bellows here is phosphor bronze,
A thin metal bag made of beryllium copper, stainless steel, or other material with a corrugated fold on its surface may be used as a normal mechanical part, and its size and shape may be adjusted according to the desired pressure difference. Can be selected.

Further, in the present embodiment, the above-mentioned bellows-shaped shield part 25 is used as the elastic part. However, if the elastic part is capable of absorbing the pressure difference between the outside and the inside, it is elastic. For example, an elastic body such as a rubber or plastic film may be used.

Also in this embodiment, as in the previous embodiment, the gas sealed inside the HDD case is replaced with an atmosphere such as air with reduced water vapor pressure or another gas such as an inert gas. It is desirable to keep.

In any of the above-described embodiments, the spindle motor having the dynamic pressure bearing portion, the disk portion including the information medium mounted on the spindle motor, and the information extraction / writing with respect to the disk portion are performed. Although a means for enclosing the entire HDD including a head section and a case to shut off the outside air is disclosed, an object of the present invention is to prevent the occurrence of dew condensation in the dynamic pressure bearing portion or to prevent the bearing portion from being depressurized even in a reduced pressure state. To generate dynamic pressure. Therefore, the technical scope of the present invention is not limited to shutting off the entire HDD function from the outside air as described above, and for that purpose, at least the dynamic pressure bearing portion is shut off from the outside air,
It is only necessary to be sealed in a gas of an appropriate atmosphere, whereby the occurrence of dew condensation can be prevented. Also, by adopting a pressure-resistant structure, dynamic pressure can be generated even in a reduced pressure state. For example, only the spindle motor 30 shown in FIG. 4 is cut off from the outside air and placed in an environment in which no dew condensation occurs, or placed in an environment where dynamic pressure is generated even in a vacuum state, and its rotational driving force is taken out to the outside to obtain a disk drive. It is also possible to provide a mechanism for rotating.

[0029]

<Example 1> In order to confirm the effect of the present invention, a comparison was made between the operation of a conventional external air communication type HDD and the operation of a completely sealed type HDD according to the first embodiment of the present invention. . As a result of operating both of them in a thermostat at a temperature of 35 ° C. and a humidity of 95%, the HDD according to the prior art stopped, whereas the HDD according to the present invention continued to operate normally.

<Embodiment 2> Two types of hermetically sealed HDD storage cases, each having a rubber plate and a bellows attached to the side surfaces of the HDD storage case shown in the second embodiment of the present invention, and their pressure adjustment. The operation was compared with a thin case of the same thickness without a mechanism. The condition at that time is HDD
The internal pressure of the storage case was 1 atm, the external pressure was 0.7 atm, the material of the storage case was aluminum, and its thickness (excluding the screw hole portion) was 1 mm. As a result of the experiment, when a storage case without a pressure adjustment mechanism was used, a write error on a disk occurred due to deformation of the case, whereas a HDD storage case with an adjustment mechanism according to the present invention was used. Did not cause any errors.
That is, it has been proved that the effect of the pressure adjusting mechanism according to the present invention suppresses deformation due to external pressure fluctuation even in a thin case.

[0031]

According to the present invention, even if there is a humidity change or a temperature change in the outside air, no condensation occurs in the HDD storage case, and therefore, the HDD which enables the spindle motor to start and rotate stably. Can be realized.

According to the present invention, wherein the HDD case has a predetermined rigidity, it is possible to generate a dynamic pressure in the gas dynamic pressure bearing portion of the spindle motor even when the outside air is in a reduced pressure state. it can.

According to the present invention, a member which can be deformed in accordance with a change in the atmospheric pressure of the outside air is arranged in a part of the HDD case, the internal pressure of the case can follow the outside, In a predetermined change in atmospheric pressure and temperature of the outside air, the case can be shut off from the outside air without using a highly rigid storage case to prevent dew condensation inside and avoid deformation of the case due to a difference in inside and outside pressure. .

[Brief description of the drawings]

FIG. 1 is a perspective view of an HDD storage case according to a first embodiment of the present invention.

FIG. 2 is a perspective view of an HDD storage case according to a second embodiment of the present invention.

FIG. 3 is a perspective view of an HDD storage case according to the related art.

FIG. 4 is a cross-sectional view illustrating an example of a spindle motor that drives an HDD.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 HDD housing 12 Cover 13 HDD case 21 HDD housing 22 Cover 23 HDD case 24 Case window 25 Bellows

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G11B 33/12 313 G11B 33/12 313U H04N 5/781 H04N 5/781 Z (72) Inventor Kaoru Murabe 1-1-1, Kunyokita, Itami-shi, Hyogo Sumitomo Electric Industries, Ltd. Itami Works F term (reference) 5B018 MA12 QA01 5D109 BB01 BB22 BB26 BB40

Claims (7)

[Claims] 1. A hard disk drive having a dynamic pressure bearing portion, wherein at least the dynamic pressure bearing portion is sealed off from outside air. 2. A hard disk drive having a dynamic pressure bearing unit, wherein a hard disk drive mechanism including a disk unit including the dynamic pressure bearing unit and a head unit for reading / writing information from / to the disk unit is shut off from outside air. Hard disk drive characterized by being sealed. 3. A part of a portion of the container for shutting off and sealing the outside air, which is in contact with the outside air, is made of a stretchable elastic body,
3. The hard disk drive according to claim 1, wherein a pressure difference between outside air and the inside of the container is reduced. 4. The hard disk drive according to claim 3, wherein the elastic body having elasticity is a bellows. 5. The inside of the container, which is isolated from the outside air, is an atmosphere in which the vapor pressure at 1 atm of the gas inside the container is 0.1 atm or less.
The hard disk drive according to any one of claims 1 to 4. 6. The hard disk drive according to claim 1, wherein air inside the case, which is cut off from outside air, is replaced with another gas. 7. The hard disk drive according to claim 6, wherein the other gas is a nitrogen gas.