JP3013538B2 - Magnetic disk drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk drive, and more particularly, to a magnetic disk drive capable of realizing high speed and large capacity.

[0002]

2. Description of the Related Art As a conventional magnetic disk drive, 3.5.
8 and 9 show a general configuration of an inch small magnetic disk drive.

A magnetic disk 3 (hereinafter, referred to as a disk) is stacked around a stationary shaft 1 and driven at a predetermined rotation speed. Magnetic heads 19 (hereinafter, referred to as heads) supported by a load arm 4 fixed to the carriage 5 that rotates about the carriage shaft 20 are arranged on both sides of the disk 3 and are formed by coils 14 and magnets 15. It is positioned on each data track on the disk 3 by the voice coil motor.

The head 19 floats on the disk 3 in a non-contact manner while maintaining a submicron flying height by the fluid force generated by the rotation of the disk 3, and reads and writes data from and to the disk in this state. These components are sealed and held from the outside by the cover 50.

The magnetic disk drive having such a structure is required to (1) increase the storage capacity and (2) increase the transfer speed.

An effective means of increasing the storage capacity is to increase the recording density. To increase the storage density, the gap between the head flying above the disk and the disk, that is, the flying height of the head is reduced. The method is adopted. Further, the transfer speed is increased by increasing the disk rotation speed.

However, a decrease in the flying height of the head causes a head crash due to minute dust, and an increase in the disk rotation speed increases the risk of a head crash due to wind turbulence. Therefore, in order to avoid these dangers, the components that make up the magnetic disk are placed in a sealed container, eliminating the risk of head crashes due to the intrusion of dust, and enclosing a low-viscosity gas or decompressed air in the container. Methods such as reducing the pressing load of the head against the disk have been used.

[0008] As a container structure of such a magnetic disk device, for example, as described in Japanese Patent Publication No. 60-59660, a structure using an O-ring in a sealed portion or Japanese Patent Application Laid-Open No. 60-2196 is disclosed.
As described in Japanese Patent Publication No. 95, a closed container in which a closed portion is connected only by bolting is disclosed.

[0009]

As the hermetically sealed structure of the magnetic disk drive, a structure using an O-ring or a structure using bolting as disclosed in the above-mentioned prior art is disclosed.

However, in the sealing method using an O-ring, O
When the ring is made of rubber or resin, molecules such as helium and hydrogen are small compared to the molecular structure of rubber or resin, so that the ring easily passes and it is difficult to reliably seal the ring for a long time. When the O-ring is made of metal, the O-ring tightening load is much larger than that of rubber or resin, so the rigidity of the O-ring tightening portion of the container must be increased and the O-ring must be tightened with a large number of bolts.

Further, it is difficult to form a structure in which the aligned divided surfaces are fastened with only bolts to seal the gas.

An object of the present invention is to provide a magnetic disk device which solves the problems of the prior art in such a magnetic disk device, that is, a magnetic disk device in which a low-viscosity gas, decompressed air and the like are sealed for a long period of time. It is in.

In order to solve the above-mentioned problems, a magnetic disk constituting a magnetic disk device, a rotation drive unit of the magnetic disk, a magnetic head for reading and writing magnetic information on the magnetic disk, and a magnetic head Actuator for moving on the disk and inside the sealed structure
Wherein the sealing structure is made of split structure, the dividing plane
Are bonded by heating, and 1 atm inside the closed structure.
Seal either air or argon below 1/3 atmosphere
The inserted magnetic disk device.

Further, a magnetic disk disposed inside the sealed structure, a rotation drive unit of the magnetic disk, a support structure member for supporting a magnetic head and an actuator unit at predetermined positions, and components of a magnetic disk device supported by the support structure member Means for fixing the protective cover partially or wholly to the support structural member, and disposing an elastic member between the support structural member and the sealing structure and between the protective cover and the sealing structure.

Further, there is provided a means for providing a groove in the sealing portion of the closed structure, that is, a division surface of the closed structure having the divided structure, or a means for using this groove as an O-ring groove and disposing an O-ring in the groove.

[0016]

[0017]

[0018]

The sealed structure for realizing the magnetic disk drive of the present invention is formed by forming a divided structure and sealing the divided portion by using a metal joining method such as welding or brazing (including soldering). You.

Therefore, it is possible to prevent the leakage of the sealed gas inside the sealed structure and the intrusion of air from outside, which occur in the conventional sealing method using the O-ring, and to form a highly reliable magnetic disk drive.

However, metal joining such as welding and brazing is a method of heating the divided surface of the closed structure, and the joint is exposed to a temperature of several hundred degrees. Therefore, the sealed structure is deformed by heating.

This deformation must not affect the positional relationship between the components of the magnetic disk drive disposed inside the sealed structure, particularly the positional relationship between the head and the disk.

According to the present invention, in order to eliminate such an influence, the support structure member for supporting the magnetic disk, the rotation drive unit of the magnetic disk, the magnetic head and the actuator unit disposed in the closed structure at a predetermined position is sealed. The elastic member was provided separately from the structure, and an elastic member was disposed between the support structure member, the closed structure, and the protective cover fixed to the support structure member and the closed structure.

By adopting such a structure, deformation of the sealed structure caused by heating at the time of joining causes relative slip between the elastic member and the sealed structure or between the elastic member and the support structure member, and deformation of the elastic member. The appropriate positional relationship between the magnetic head and the magnetic disk is maintained without being directly transmitted to the supporting structure member that supports the components constituting the magnetic disk device, being absorbed by the deformation.

When the closed structure is formed by metal joining such as welding or brazing, there is a risk that foreign matter generated in the joint due to joining may enter the inside of the closed structure. Such intrusion of foreign matter into the inside of the closed structure can be collected by the groove provided on the division surface inside the joint of the closed structure. Further, by using this groove as an O-ring groove and arranging the O-ring in the groove, the trapping effect is improved. The O-ring is made of a material having high heat resistance, and the wider the gap between the joint and the O-ring groove, the more the effect of preventing the O-ring from deteriorating and preventing foreign matter from entering is further improved.

Further , one air or argon gas is placed in a closed container.
By encapsulating at a pressure of 1/3 atm below the atmospheric pressure
Windage and wind turbulence can be reduced.

[0026]

[0027]

[0028]

Embodiment 1 Embodiment 1 will be described with reference to FIGS. 6
The discs 3 are stacked on the hub 14 with the spacer 17 interposed therebetween and fixed by the clamp 2. This disk 3
The motor rotates at high speed around the stationary shaft 1 by a motor (not shown) built in the hub 14. The surface of the disk 3 is coated with a magnetic material and is finished smoothly.

The head 19 is arranged opposite to both surfaces of each disk 3 and floats on the disk 3 with a submicron flying height by the fluid force generated as the disk 3 rotates.

In this state, the head 19 records and reproduces magnetic information written in a concentric portion called a track having the same center as the mechanical rotation center of the disk 3.

The head 19 is supported by the head arm 4 and the carriage 5, has a structure capable of rotating around the carriage shaft 20, and can move to an arbitrary track.

A voice coil motor formed by the coil 52 and the magnet 15 is used for positioning the head 19 and moving between tracks, and performs high-speed and accurate positioning.

The positions of the stationary shaft 1, which is the center of rotation of the disk 3, the carriage shaft 20, which is the center of rotation of the carriage 5, and the magnet yoke 9 which supports the magnet 15, are changed by the components of the magnetic disk drive due to vibration, impact, and the like. Structural support member 1 having sufficient rigidity
6 fixed. The support structure member 16 has a protective cover 50 that partially covers all the components of the magnetic disk.
Has been fixed. The closed structure 8 is configured so as to cover the support structure member 16 and all other components of the magnetic disk and to shield it from the outside.

An elastic member 21 is disposed between the support structure member 16 and the closed structure 8 and between the protective cover 50 and the closed structure 8. The elastic member 21 is made of soft and elastic rubber that absorbs deformation of the closed structure 8 and vibrations and shocks from the outside and does not transmit the deformation to the support structure 16.
Further, the corners of the support structure member 16 were lightly fixed by the leaf spring 12 attached to the inside of the closed structure 8.

The closed structure 8 has a divided structure, and the divided surfaces are sealed by a closed portion 13 joined by a welding method.
The seam welding method was used as the welding method, and the rotating electrodes were sandwiched from above and below the divided part (sealed part), and electricity was supplied. The sealing portion 13 was made thin so as to facilitate welding. An O-ring groove 51 is provided on the inside of the sealing portion 13 on the dividing surface, and an O-ring 18 is arranged in the groove to prevent foreign substances generated at the time of joining from entering the inside of the device.

On the side surface of the sealed structure 8, a connector 6 for transmitting signals between the inside and the outside and supplying a driving power, a flange 11 for replacing air and gas to be sealed in the device, and a valve 10 are provided.
Is provided.

After the magnetic disk drive having the above-described configuration was formed, a helium leak detector was connected to the flange to check the confidentiality. The leak rate was 10 to ¹⁰ atm c.
c / sec was achieved. Thereafter, helium gas was sealed in the sealed structure. In the sealing method, first, a vacuum evacuation device and a helium gas cylinder were connected to the flange 11, the air in the sealed structural member 8 was exhausted, and then helium gas was inhaled to 0.5 atm by operating a valve.

In this embodiment, helium gas is used as the sealing gas. However, when helium gas or hydrogen gas is sealed in the sealed structure, as shown in FIG. The flying height decreases. That is, in order to obtain the same flying height as in the case of air, the load of pressing the head against the disk can be reduced. Further, by reducing the pressure, the pressing load can be greatly reduced, and the damage caused when the head crashes due to the contact between the head and the disk can be reduced.

When this apparatus was operated, stable operation without malfunction was performed for a long period of time, and it was confirmed that the magnetic disk apparatus was highly reliable.

In this embodiment, rubber and a leaf spring are used as the elastic member. However, the same effect can be obtained by using an elastic body such as a coil spring and resin. Further, in this embodiment, the seam welding method is used as the welding method, but the same hermeticity can be obtained by using TIG welding or plasma TIG welding. Furthermore, brazing may be used instead of the welding method as a sealing method.

Embodiment 2 will be described with reference to FIGS. In the magnetic disk drive of the present embodiment, the support structure member 16 for supporting the components of the magnetic disk drive and the sealing structure 8 are connected by an elastic member 21, and the disk 3 is mounted on the disk except for the portion where the head arm 4 enters and exits. It is covered with a shroud 23 that covers the whole in close proximity.

The sealing portion 13 of the sealing structure 8 is joined with Sn4
A method was used in which eutectic solder having a composition of 0% and 60% Pb was used, and heating was gradually performed by a burner while supplying solder to a thin portion on the outer peripheral portion of the sealed portion 13. Also in this embodiment, consideration was given to making the heat capacity small by making the sealing portion thin. Further, an O-ring groove 18 is provided inside
The joining was performed with the ring 51 inserted. After joining, a helium leak test was performed to confirm airtightness, and the air in the closed structure 8 was reduced to 0.33 atm.

When air is enclosed, the thermal conductivity decreases as the pressure is reduced as shown in FIG. In addition, the load of the bearing generated in the disk rotation drive unit out of the total load applied to the motor is constant independently of the gas pressure. The windage loss decreases as the pressure decreases, but becomes substantially constant below about 1/3 atmosphere. Therefore, the load is reduced by the amount corresponding to the decrease in windage.

On the other hand, the thermal conductivity decreases almost uniformly as the pressure decreases. For this reason, the temperature distribution in the apparatus decreases as the pressure decreases, but increases at about 1/3 atmosphere.

Accordingly, it can be seen from FIG. 6 that the air pressure is less than 1 atm.
3 atm or more is desirable.

Since both the density and the thermal conductivity of nitrogen and argon are substantially equal to those of air, the set pressure is desirably 1 atm or less and 1/3 atm or more as in the case of air.

The windage loss and wind turbulence generated by the rotation of the disk are greatly reduced by reducing the pressure inside the closed structure because it is proportional to the gas density. The risk of crash is reduced.

The heat pipe 22 penetrating from the inside of the closed structure 8 to the outside was provided on the side surface on the voice coil side.

In the present embodiment, the shroud restricts the flow of gas generated as the disk rotates around the disk, thereby reducing windage and windage.
There is an effect of reducing wind turbulence and an effect that heat generated in the voice coil and the disc in the device can be easily discharged to the outside of the closed structure by the heat pipe.

Embodiment 3 will be described with reference to FIG.

In this embodiment, the support structure member 16 that covers the components of the magnetic disk drive with the protective cover 50 and supports the components of the magnetic disk drive at a predetermined position is opened at the side surface thereof so that the air can be ventilated inside. A total of 10 units were arranged, two units for each layer in the structure having a layered structure. An elastic member 21 was disposed between the support structure member 16 supporting the components of the magnetic disk device and the bottom surface of each layer. Next,
A plate-like side plate was joined to the side surface by seam welding. The welded portion was provided with a thin portion to facilitate welding.

The magnetic disk devices arranged in the closed structure were connected in parallel, and the overall configuration was optimized for an array disk system operated as a high-speed axis disk device.

A heat pipe 22 penetrating through the closed structure 8 was provided above the closed structure 8. Further, a gas reservoir 28 communicating with the inside of the closed structure 8 was provided. The gas pool is sealed by a flexible material 25 and sealed air 24
Is filled with a known gas, and a detector made of a strain gauge 26 is attached to the flexible material 25. A means (not shown) for evaluating and determining the output of the detector and generating a warning is provided.

In this embodiment, a change in pressure of the gas sealed in the sealed structure can be detected, and leakage from a defect can be captured at an initial stage, so that the magnetic disk device disposed inside can be operated stably. In particular, there is an effect that it is possible to prevent head crashes and defective reading and writing of magnetic information, which are caused by an increase or decrease in the flying height of the head, which is greatly affected by fluctuations in gas pressure.

Further, since the heat pipe 22 is provided above the closed structure, heat generated from each magnetic disk device can be efficiently removed.

[0056]

According to the present invention, a hermetically sealed structure can be formed, windage and wind turbulence can be reduced, and deformation of the sealed structure, external vibration and impact can be applied to the components of the magnetic disk drive. A large-capacity magnetic disk drive capable of high-speed rotation with high head crash resistance that is not directly transmitted can be realized.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a first embodiment.

FIG. 2 is a longitudinal sectional view of the first embodiment.

FIG. 3 is a diagram showing a relationship between gas pressure and head flying height.

FIG. 4 is a cross-sectional view of the second embodiment.

FIG. 5 is a longitudinal sectional view of the second embodiment.

FIG. 6 is a diagram showing a relationship among a gas pressure, a load, a temperature distribution in the apparatus, and a thermal conductivity.

FIG. 7 is a sectional view of a third embodiment.

FIG. 8 is a cross-sectional view of a conventional magnetic disk drive.

FIG. 9 is a longitudinal sectional view of a conventional magnetic disk drive.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Static axis | shaft, 2 ... Clamp, 3 ... Magnetic disk, 4 ... Load arm, 5 ... Carriage, 6 ... Connector, 7 ... Lead wire, 8 ... Sealed structure, 9 ... Magnet yoke, 10 ...
Valve, 11: flange, 12: leaf spring, 13: sealed part, 1
4 ... Hub, 15 ... Magnet, 16 ... Support structural member, 1
7 spacer, 18 O-ring, 19 magnetic head, 2
0: Carriage shaft, 21: Elastic member, 22: Heat pipe, 23: Shroud, 24: Gas pool, 25: Partition plate, 26: Strain gauge, 27: Support leg, 50: Protective cover, 51: O-ring groove, 52 ... coil.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor, Akio Takatsuka 2880 Kozu, Kokuzu, Odawara-shi, Kanagawa Prefecture Inside the Hitachi, Ltd.Odawara Plant 72) Inventor Toshiaki Makino 502, Kandachi-cho, Tsuchiura-shi, Ibaraki Pref. Machinery Research Laboratory, Hitachi, Ltd. (56) References JP-A-52-38908 (JP, A) JP-A-63-140472 (JP, A) JP-A-61-115291 (JP, A) JP-A-62-257695 (JP, A) JP-A-63-117378 (JP, A) JP-A-62-38561 (JP, A) , A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G11B 33/12 313 G11B 25/04 101

Claims (3)

(57) [Claims] A magnetic disk, a rotation drive unit for the magnetic disk, a magnetic head for reading and writing magnetic information on the magnetic disk, and an actuator unit for moving the magnetic head on the magnetic disk. In the magnetic disk device provided in the closed structure, the closed structure has a divided structure, and the divided surfaces are joined by heating and joining, and the inside of the closed structure has a pressure of 1 atm or less.
A magnetic disk drive in which either air or argon of at least / 3 atm is sealed. 2. The magnetic disk drive according to claim 1, wherein said magnetic disk, a rotation drive unit of said magnetic disk, said magnetic head and said actuator unit are supported by a support structure member supporting a predetermined position. A magnetic disk drive comprising a support structure member provided in the closed structure via an elastic body. 3. The magnetic disk drive according to claim 1, wherein an O-ring groove is provided inside the heat-bonding portion of the sealed structure, and an O-ring is arranged in the O-ring groove to perform heat bonding. A magnetic disk drive characterized by the above-mentioned.