JP2001110178A - Hard disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hard disk drive suitable for high-speed revolution such that increase in frictional resistance can be avoided even in high-speed rotation of a storage medium. SOLUTION: The inside of a case 3 for storing an HDD is hermetically sealed by shutting off the outdoor air, while the air sealed in the case 3 is evacuated to about 0.9-0.5 atmospheric pressure. Reduction in air resistance is contrived. The air hermetically sealed inside the case 3 is replaced with a gas having a small viscous resistance, thereby enabling further reduction in rotary resistance to be realized. This gas for the replacement is desirably nitrogen gas. Also, by keeping the moisture content low for the evacuated air to be sealed in the case, or by replacing the air with a gas containing no moisture, failure such as re-starting disability owing to dew condensation can be eliminated simultaneously even in the case where a dynamic pressure bearing is employed for the rotary part of the HDD.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hard disk drive (hereinafter abbreviated as HDD) used as a storage device of a computer.

[0002]

2. Description of the Related Art FIG. 2 shows an outline of a conventional HDD. In the figure, reference numeral 11 denotes a housing for housing an HDD. Inside the housing 11, an HDD having 20 disk units and 30 head units as main components is housed. The disk unit 20 has a rotation speed of 10,000.
The spindle motor 21 includes a spindle motor 21 rotating at a high speed of 0 rpm or more, or more, and a plurality of storage media (hard disks) 25 having an information storage surface mounted on the outer periphery of the spindle motor 21. The head unit 30 is provided with the storage medium 2 rotating at a high speed.
5, a plurality of head assemblies 31 for accessing the information storage surface and recording or reproducing necessary information, a carriage 35 supporting the head assemblies 31, and the head assemblies 31 accessing necessary parts of each storage medium 25. And a head mount 38 for pivotally operating the carriage 35.

FIG. 3 is a sectional view showing a spindle motor 21 mounted on a storage medium 25 constituting the disk unit 20 of the HDD as described above. In the figure, 22 is a base, 23 is a shaft fixed to the base 22, 24
Is a ball bearing pressed into the shaft 23,
The ball bearing 24 rotatably supports 26 rotor hubs on the outer periphery. The plurality of storage media 2
Numerals 5 are mounted on the outer periphery of the rotor hub 26 at predetermined intervals so that information can be recorded / reproduced on the information storage surface, and are mounted in parallel with the surface perpendicular to the axis of the shaft 23. 27 is a stator fixed to the housing 22,
A coil 28 is wound around the stator 27 and the rotor hub 26
And 29 rotor magnets fixed to the inner peripheral surface of the rotor magnet.

The operation of the spindle motor 21 configured as described above is performed by energizing the coil 28.
A repulsive / attracting force acts between the stator 27 and the rotor magnet 29, thereby generating a rotational driving force for the rotor hub 26, and the rotor hub 26 rotates around the shaft 23 via the ball bearing 24, and the rotor hub 26 rotates. The storage medium 25 attached to the camera rotates. The rotating storage medium 25 is accessed by a head assembly (not shown), and necessary information is extracted from the information stored in the storage medium 25, or the required information is recorded on the storage medium 25.

With respect to the spindle motor 21 having the above-described ball bearing 24, non-contact rotation with higher speed and higher accuracy has been performed in accordance with recent demands for miniaturization, high speed, and large capacity of a storage device. Attention has been paid to the use of a dynamic pressure bearing that can be realized, in particular, a spindle motor having a dynamic pressure gas bearing that does not generate heat even at high speed rotation and is easy to handle.

FIG. 4 is a sectional view showing a spindle motor 31 provided with such a dynamic pressure gas bearing. In the figure, 32 is a base, 33 is a shaft fixed to the base 32, 34 is a sleeve fitted on the outer peripheral surface of the shaft 33 with a predetermined gap, and 35 is a shaft perpendicular to the axis of the shaft 33. Attached to the surface, the sleeve 34
The thrust plate is disposed so as to face one of the axial end surfaces, and these members 33, 34, and 35 constitute a dynamic pressure bearing. On the surface of the thrust plate 35 facing the end face of the sleeve 34, a groove for generating thrust dynamic pressure indicated by a dotted line 36 is provided. The sleeve 34 is fixed to a rotor hub 37, and a plurality of storage media 25 are mounted on the outer peripheral surface of the rotor hub 37. Other configurations are the same as those shown in FIG. 3 above, and the same components are denoted by the same reference numerals.

The operation of the spindle motor 31 configured as described above is performed by energizing the coil 28.
A repulsion / attraction force acts between the stator 27 and the rotor magnet 29, thereby generating a rotational driving force for the rotor hub 37, and the sleeve 34 fixed to the rotor hub 37 rotates about the shaft 33, and the rotation causes The shaft 33 and the sleeve 34 are kept in a non-contact state by the generated radial dynamic pressure. On the other hand, the relative rotation between the end face of the sleeve 34 and the thrust plate 35 causes the groove 3
6 generates a dynamic pressure in the thrust direction, so that the sleeve 34 floats from the thrust plate 35 and
4, the rotor hub 37, and the rotating members other than the storage medium 25 rotate at high speed without contacting the whole.

Returning to FIG. 2, a head assembly 31, which is a component of the head unit 30, is inserted for each information medium 25 into the disk unit 20 which is rotated at a high speed by the spindle motor having the above-described configuration, and By the pivot operation of 35, the head assembly 31 accesses the information storage surface of each information medium 25 and takes out or writes information.

The disk unit 20 and the head unit 30 configured as described above are housed in the housing 11 shown in FIG.
A cover 12 is screwed over the housing 11. As a result, the entire HDD is housed in the HDD case 13 formed by the housing 11 and the cover 12. The inside of the case 13 is connected to the outside air through 15 windows provided on the side surface of the housing 11 shown in the figure. The 16 filters attached to the windows 15 prevent dust and the like from entering the inside. This protects the spindle motor 21 and other precision machine elements.

[0010]

SUMMARY OF THE INVENTION As described above, HDDs
With the demand for larger capacity, the rotation speed of the spindle motor and the storage medium mounted on the spindle motor is increased, so that the air resistance (windage) of the rotating member including the storage medium is increased.
Tend to be even larger. Especially 10,000 rpm
In the region of rpm or more, problems such as an increase in power consumption due to an increase in drive torque, an increase in wind noise, heat generation due to friction with air, and an increase in the temperature inside the HDD storage case due to the problem arise.

Further, in the HDD using the spindle motor 31 provided with the dynamic pressure bearing, the filter 1
The inside of the case 13 and the outside air communicate with each other through the inner ring 6, so that when the humidity of the outside air rises or a sudden temperature change occurs, the moisture in the air is compressed by the air compression effect in the dynamic pressure bearing portion. Condensation may form. These dynamic pressure generating parts are in contact at rest, and even when rotating, the clearance between them is only a few microns, so
If the condensation occurs, the spindle motor 31 may not be able to be started, or even if it is started, the rotation may vary.

As described above, according to the present invention, when a storage medium of an HDD is rotated at a high speed, adverse effects such as an increase in driving torque and an increase in power consumption due to friction with air, an increase in wind noise, and heat generation are reduced. An object is to provide an HDD suitable for high-speed rotation.

Further, the present invention provides a bearing which can be easily restarted and has stable high-speed rotation without dew condensation at the bearing portion even when the HDD employs a dynamic pressure bearing for the bearing portion. It is an object of the present invention to provide a highly-reliable HDD equipped with the HDD.

[0014]

SUMMARY OF THE INVENTION According to the present invention, the above-mentioned HDD case comprising a housing and a cover is sealed off from outside air, and the inside of the case is decompressed, thereby reducing the adverse effects caused by the air resistance. By reducing the moisture content of the gas sealed in the case, the problem of dew condensation is also solved. Further, in the present invention, the inside air is replaced with a predetermined gas so that the inside of the case has an atmosphere that simultaneously reduces air resistance and avoids dew condensation. The specific contents are as follows.

That is, according to the present invention, there is provided a disk unit on which a storage medium mounted on a spindle motor rotates, and a head unit for accessing the rotating storage medium to record and reproduce information. And a case accommodating the disk unit and the head unit, wherein the case is shut off from outside air and hermetically sealed, and the inside of the case is decompressed.

According to a second aspect of the present invention, in the hard disk drive according to the present invention, the pressure inside the case is about 0.
It is characterized by being between 9 atm and about 0.5 atm.

According to a third aspect of the present invention, in the hard disk drive according to the present invention, the pressure inside the case is about 0.3.
It is characterized by 7 atm.

A hard disk drive according to a fourth aspect of the present invention is characterized in that the air sealed inside the case is dehumidified air.

A fifth aspect of the present invention is a hard disk drive according to the present invention, wherein the pressure of water vapor contained in one atmosphere of the dehumidified air is about 0.005 atmosphere or less.

A hard disk drive according to a sixth aspect of the present invention is characterized in that the gas sealed in the case is replaced by another gas having a low frictional resistance.

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

[0022]

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, 1 is a housing, 2 is a cover for covering the housing 1, and both of them constitute an HDD case 3. The housing 1 is not provided with a window portion that communicates with the outside air as in the prior art, and furthermore, a material that exhibits sufficient strength to withstand a pressure difference between the inside and the outside that is predetermined according to the purpose. It is made up of wall thickness. Therefore, at the time of use, the cover 2 is fixed to the housing 1 with a plurality of screws.
The D case 3 is sealed, and the inside is isolated from outside air. Note that the HDD internal mechanism to be accommodated in the HDD case 3 is composed of the main parts of the disk unit 5 and the head unit 6 and the details thereof are the same as those of the above-described conventional technology, and thus the details are omitted. .

This embodiment is characterized in that the pressure inside the HDD case 3 sealed as described above is reduced to reduce the frictional resistance due to air. For this decompression, for example, a through-hole is previously provided at an arbitrary position such as the cover 2 of the HDD case 3, and after the cover 2 is sealed, a vacuum pump is connected to the through-hole to reduce the pressure, and then the through-hole is closed. Can be easily implemented. The degree of decompression can be selected at a required level depending on the relationship with the HDD specifications such as the number of revolutions.
It is conceivable to reduce the pressure from the atmospheric pressure to about 0.5 atmospheric pressure.
If necessary, the pressure may be further reduced. According to an experiment conducted by the inventors of the present application, when pressure is reduced to 0.7 atm, an effect of improving power consumption, sound, and heat is recognized.

One of the points to be noted in the case of the decompression is to solve the problem of the strength of the case 3 that can resist the decompression. As described above, this involves changing the material and thickness of the case 3. It can be handled by design changes such as addition of ribs.
If the case 3 is deformed due to insufficient strength, it may affect the HDD performance itself, and it is necessary to maintain a certain rigidity in the case 3 according to the degree of pressure reduction. Another point to be noted is that when the spindle motor of the HDD employs a hydrodynamic bearing, the decompression changes the levitation characteristics of the rotating side member of the bearing, and the rotation speed at the start of levitation increases to increase the bearing speed. There is a possibility that the wear of the part is promoted or the resistance to the swing from the outside is reduced. For this reason, when a dynamic pressure bearing is used for the bearing portion of the HDD, extreme pressure reduction cannot be performed. According to the experiments performed by the inventors, no particular problem was found even when the dynamic pressure bearing was used at about 0.7 atm.

Next, an HDD according to a second embodiment of the present invention will be described. When the spindle motor used in the HDD has a dynamic pressure bearing as shown in FIG. 4, the air interposed in the bearing portion is compressed by the relative movement between the bearing members as described above, When pressure is generated, moisture contained in the air may condense. Alternatively, if the outside air drops to, for example, around 0 ° C. after the air is once sealed, moisture in the air may condense. If the spindle motor is provided with the ball bearing 24 as shown in FIG. 3, there is no particular problem even if dew condensation occurs. However, in the case of a dynamic pressure bearing, adverse effects such as difficulty in restarting occur. .

In the present embodiment, in order to avoid the above-mentioned problem, the water content in the air which is sealed in the HDD case 3 and used under reduced pressure is reduced in advance. This moisture reduction can be performed by passing air to be sealed in the HDD case 3 through a dehumidifier in advance. The degree of dehumidification is such that condensation does not occur in the dynamic pressure bearing according to the operating conditions of the spindle motor. For this reason, generally, the water vapor pressure at 1 atm of air before being sealed in the case 3 is defined as: About 0.005
It is preferable to keep the pressure below the atmospheric pressure.

Next, an HDD according to a third embodiment of the present invention will be described. In the present embodiment, the gas sealed in the case 3 is replaced with another gas instead of air. For example, if a specific gas is selected such that the viscosity of the gas is low and the frictional resistance is reduced even when the spindle motor rotates in the atmosphere, the further improvement effect can be obtained in addition to the decompression of the air as described above. Obtainable. The effect of replacing air with a specific gas is, in addition to the reduction of the resistance caused by the rotation, when the spindle motor is of a dynamic pressure gas bearing, other gas that does not contain moisture in advance is used. By replacing with, the dew condensation can be avoided. Furthermore, the durability of the HDD can be improved by selecting and filling an inert gas that does not deteriorate the HDD equipment housed in the case.

Nitrogen gas is a preferred gas that meets all of the above conditions and that can be obtained at low cost.
However, the present invention is not limited to this, and may be any gas that can realize an atmosphere satisfying the above conditions.

The embodiments according to the present invention have been described above. Compared with the case where a conventional HDD case communicating with the outside air is used, the sealed gas is made dust-free, so The durability and reliability of the dynamic pressure bearing which is easily affected can be improved. Also, even when the HDD is used in a special environment such as a situation where there is a large change in atmospheric pressure or humidity, or a use in an atmosphere such as a harmful gas, the HDD is housed in a closed container. Has the side effect of being able to operate without any adverse effects.

[0030]

According to the present invention, by setting the inside of the HDD storage case to a reduced-pressure atmosphere, the frictional resistance with air in the high-speed rotation part is reduced, and the power consumption is increased by the resistance.
Problems such as generation of noise and heat generation can be avoided.

Further, by making the inside of the HDD storage case a dehumidifying atmosphere, especially when the HDD spindle motor has a dynamic pressure bearing, it is possible to eliminate rotation problems and start-up problems due to condensation.

Further, by setting the inside of the HDD storage case to a specific selected atmosphere, the frictional resistance of the rotating part can be further reduced, or the durability of the HDD can be improved by preventing the deterioration of the HDD equipment. be able to.

Further, since the HDD storage case has a sealed structure, the inside is filled with a gas of a predetermined pressure even when the outside air is in a reduced pressure state or in an extremely vacuum state. Since the gas necessary for generating dynamic pressure is secured in the dynamic pressure bearing portion of the spindle motor, H
There is no hindrance to the DD function.

[Brief description of the drawings]

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

FIG. 2 is a perspective view of an HDD storage case according to the related art.

FIG. 3 is a cross-sectional view illustrating an example of a spindle motor that drives an HDD.

FIG. 4 is a sectional view showing an example of another spindle motor for driving an HDD.

[Explanation of symbols]

1. Housing, 2. Cover, 3. 4. HDD storage case, 5. Disk part, Head part, 21. Spindle motor, 22. Storage media, 31. Spindle motor.

Continued on the front page (72) Inventor Kaoru Murabe 1-1-1, Kunyokita, Itami-shi, Hyogo F-term (reference) in Itami Works, Sumitomo Electric Industries, Ltd. 5D109 AA03 AA20

Claims (7)

[Claims] 1. A disk unit on which a storage medium mounted on a spindle motor rotates, a head unit for accessing the rotating storage medium to record and reproduce information, and a disk unit and a head unit. A hard disk drive comprising: a case to be stored; wherein the case is sealed off from outside air, and the inside of the case is depressurized. 2. The hard disk drive of claim 1, wherein the pressure inside the case is between about 0.9 atmosphere and about 0.5 atmosphere. 3. The hard disk drive according to claim 2, wherein the pressure inside the case is about 0.7 atm. 4. The air sealed inside the case,
The hard disk drive according to any one of claims 1 to 3, wherein the hard disk drive is dehumidified air. 5. The hard disk drive according to claim 4, wherein the pressure of water vapor contained in one atmosphere of the dehumidified air is about 0.005 atmosphere or less. 6. The hard disk drive according to claim 1, wherein the gas sealed in the case is replaced by another gas having a small frictional resistance. 7. The hard disk drive according to claim 6, wherein the other gas is a nitrogen gas.