JP2001307458A - Information recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low price, high-density and fast-transfer-rate information recording device which solves the problems of windage loss, vibration, noise, etc. that a fast rotation type information recording device has. SOLUTION: The information recording device has a recording medium, a driving part which drives the recording medium in the recording direction, a head equipped with a recording part and/or reproduction part, a means which moves the head relative to the recording medium, and a recording and reproduction signal processing means which inputs a recording signal to the head and outputs a reproduction signal from the head. At least the recording medium, driving part, head, and relative moving means are put in an airtight case and the density of the air in the case is held lower than the that of the atmosphere.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording apparatus, such as a magnetic disk drive, provided with a recording medium and a head.

[0002]

2. Description of the Related Art An information recording device represented by a magnetic disk device is widely used as an external storage device of an information processing device such as a computer, and in recent years, is also used as a moving image recording device or a recording device for a set-top box. Is being done. A magnetic disk device generally includes a shaft for fixing one or more magnetic disks in a skewered manner, a motor for rotating a magnetic disk joined to the shaft via a bearing, and a floating used for recording and / or reproduction. Type magnetic head, an arm to which the head is attached, and an actuator that can move the head to an arbitrary position on the magnetic recording medium via the head arm, and the recording / reproducing head moves on the magnetic recording medium. It is moving at a constant flying height.

A magnetic recording medium mounted on a magnetic disk drive generally has a NiP layer formed on the surface of a non-magnetic substrate made of an aluminum alloy or the like, performs a required smoothing process, a texturing process, and the like, and then forms a NiP layer on the NiP layer. In addition, a nonmagnetic metal underlayer, a magnetic layer, a protective layer, a lubricating layer, and the like are sequentially formed. Alternatively, a nonmagnetic metal underlayer, a magnetic layer (information recording layer),
It is manufactured by sequentially forming a protective layer, a lubricating layer, and the like. The density of magnetic recording media has been increasing year by year, and in recent years, the density has been increasing at an annual rate of 60% or more. There are various techniques for realizing this high density, such as reducing the flying height of the magnetic head, employing a GMR head as the magnetic head, and improving the magnetic material used for the recording layer of the magnetic disk. Attempts have been made to reduce the distance between information recording tracks on a magnetic disk.

[0004]

In recent years, the number of rotations of a magnetic recording device has been increased in order to improve the transfer speed. However, as the rotation speed increases, a loss due to friction between the gas inside the drive (recording device) and the rotating medium increases, and there is a problem that power consumption of the device increases. In addition, the high-speed airflow also acts on the head, so that the head bottom area for maintaining an appropriate flying height becomes extremely small, and there is a problem that the surface is easily affected by surface undulations. Further, there is a problem that the medium vibrates due to the turbulence of the air flow accompanying the rotation of the medium. To solve the latter,
Although measures such as using a medium substrate with high rigidity and increasing the thickness of the medium are taken, a medium substrate with high rigidity is generally expensive, and if a thick medium is used, the number of media that can be stored in a drive of a predetermined thickness And the recording capacity decreases. The present invention solves problems such as windage loss, vibration, and noise in a high-speed rotation type information recording device without using such a special recording medium or a small head, and provides a high-density and high transfer speed information recording device. The purpose is to provide a low-cost.

[0005]

SUMMARY OF THE INVENTION The gist of the present invention is to provide a recording medium, a driving unit for driving the recording medium in a recording direction, a head having a recording unit and / or a reproducing unit, An information recording apparatus comprising: a recording / reproducing signal processing unit for inputting a recording signal to the head and outputting a reproduction signal from the head; and at least a recording medium, a driving unit, and a head. The relative movement means is housed in an airtight case, and the density of the gas inside the case is kept lower than that of the atmosphere. As a result, the frictional resistance with the gas accompanying the driving such as rotation and movement of the recording medium is reduced, and the windage, vibration,
Noise and the like can be suppressed. The present invention is particularly advantageous when applied to a high-speed information recording apparatus in which a recording medium is rotated and recording and / or reproduction is performed by a head, and the number of rotations is 10,000 rpm or more. One preferred form maintains the pressure inside the case below atmospheric pressure. A preferred pressure range is from 0.1 atm to 0.9 atm at room temperature. In another preferred embodiment, the case is filled with a gas having a smaller molecular weight than the atmosphere. In particular, helium gas is preferable because of its low specific gravity, high thermal conductivity and inertness.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
According to the present invention, in an information recording device such as a magnetic disk device, at least the recording medium, the drive unit, the head, and the relative moving means are housed in an airtight case, and the density of the gas inside the case is made lower than the atmosphere. As a result, the frictional resistance with gas due to driving such as rotation and movement of the recording medium is reduced,
Reduce windage, vibration, noise, etc. Here, the atmosphere generally refers to air near 0 meters above sea level at 25 ° C. Here, the airtight case is a case made so that the gas used in the present invention is sealed and held in the case.

The phenomenon caused by a moving fluid is governed by the Reynolds number. The Reynolds number (Re) is expressed by the following equation (1), where ρ is the density of the fluid, μ is the viscosity (viscosity), U is the average velocity, and d is the representative length.

Re = ρ U d / μ (1) That is, if the density ρ of the fluid is small and the viscosity μ is large, it can be seen that the Reynolds number is low even when the fluid moves at high speed. Since the turbulence of the air flow inside the device is governed by the Reynolds number, the use of low-density gas or high-viscosity gas allows the same air flow even at higher rotations compared to operation in air. It is possible to suppress the disturbance. The same effect can be obtained by reducing the gas pressure in place of the gas having a low density. The frictional resistance due to the fluid is given by the coefficient given as a function of the Reynolds number multiplied by the square of the density and velocity. This coefficient is a complicated function of the Reynolds number, but in a turbulent flow region, which is a general operation region, shows a gradual decrease tendency with an increase in the Reynolds number. This means that when the viscosity is increased to reduce the Reynolds number, the frictional resistance increases. For this reason, an increase in viscosity has an adverse effect on a decrease in frictional resistance.

On the other hand, when the Reynolds number is decreased by decreasing the density, the friction coefficient slightly increases, but the friction resistance is a value obtained by multiplying the coefficient by the density. Generally lower. Therefore, by performing the operation in a low-density gas, the frictional resistance can be reduced and the vibration due to the turbulence can be suppressed. As a preferable mode for keeping the density of the gas inside the case low, the pressure inside the case is made lower than the atmospheric pressure (1 atm). Generally, in a closed container, a structure that is strong against pressure reduction is weak against pressure, and a structure strong against pressure is weak against pressure reduction. For this reason, it is preferable that the internal pressure be maintained in a reduced pressure state or a pressurized state throughout the operation. Therefore, considering the temperature change accompanying the operation of the apparatus, it is preferable that the pressure in the container is reduced by 10% or more with respect to the atmospheric pressure.
Therefore, the pressure in the airtight case containing the recording medium, the drive unit, the head, and the relative moving means is preferably set to 0.9 atm or less at room temperature. More preferably, the pressure is set to 0.8 atm or less. Note that room temperature refers to 25 ° C. However, a remarkably low pressure is not preferable because even a slight leak greatly changes the pressure and gas composition in the container, and also hinders the stable floating of the head.

In another preferred embodiment, the case is filled with a gas having a smaller molecular weight than the atmosphere. The molecular weight of the atmosphere here means that oxygen and nitrogen, which are the main gas in the atmosphere,
This is a calculation based on a ratio of nitrogen 4 to oxygen 1, and the value is about 28.8. As the gas, for example, helium, hydrogen, neon, nitrogen, or the like can be used. Since a low molecular weight gas also has a property of good thermal conductivity, heat generated from a driving unit or a relative moving unit can be quickly transmitted to the outside, which is preferable. This is particularly advantageous in a device in which a head is moved by a voice coil type actuator which generates much heat. Helium and hydrogen are particularly preferred because of their high thermal conductivity. In view of the stability as a gas, helium, which is an inert gas, is particularly preferred.
A low molecular weight gas may be sealed at a low pressure to further reduce the density. Generally, special gases are expensive, but they also save gas consumption. Helium has a very high thermal conductivity, so that a high thermal conductivity can be kept high even when sealed at a low pressure. In particular, a device that does not have a problem of heat transfer can be more economically implemented by, for example, enclosing a nitrogen gas having a density at normal pressure equal to that of air and reducing the gas density by reducing the pressure.

The present invention relates to an apparatus for recording and reproducing data by rotating a recording medium such as a magnetic disk.
When applied to an information recording device that rotates at a high speed above pm,
Particularly, the effect is large and preferable. Conventionally, the rotation speed of a recording medium such as a magnetic disk was about 3600 rpm,
In recent years, the number of rotations of a recording medium has been increasing with the demand for an increase in data transfer speed, and information recording apparatuses having a rotation number of the recording medium of 10,000 rpm or more are being used. However, the rotation speed of the recording medium is usually 20,000 rpm or less. It is said that the rotation speed of a recording medium is limited to tens of thousands of rpm in the case where a bearing that is currently mainstream is used for a rotating portion of an information recording device. Further, in order to achieve high rotation, it is said that it is possible to realize about 100,000 rpm by using an air bearing in a rotating part of the information recording apparatus.

A magnetic disk device, which is a typical information recording device, will be described as an example. A magnetic disk device generally includes a shaft for fixing one or more magnetic disks in a skewered manner, a motor for rotating a magnetic disk joined to the shaft via bearings, and a magnetic disk used for recording and / or reproduction. A head, an arm to which the head is attached, and an actuator capable of moving the head to an arbitrary position on the magnetic recording medium via the head arm. It is moving at a flying height. The recording information is converted into a recording signal via a signal processing means and recorded by a magnetic head. Further, the reproduction signal read by the magnetic head is inversely converted through the signal processing means to obtain reproduction information.
On the disk, information signals are recorded in sector units along concentric tracks. Servo patterns are usually recorded between sectors. The magnetic head reads a servo signal from the pattern, thereby accurately performing tracking at the center of the track, and reads an information signal of the sector. Tracking is also performed during recording.

In the present invention, the magnetic disk drive is housed in a confidential case. The shape of the case may be an egg-shaped shape in which all partitions are configured with curved surfaces as shown in FIG. 1 in order to have strength enough to withstand reduced pressure or positive pressure for replacing the gas inside. preferable. This shape is also preferable in that the filling gas can be saved. In order to keep the case airtight, as shown in FIG. 2, a thermoplastic resin sheet is sandwiched between joints of the case, and the resin sheet is fused to both joint surfaces by applying ultrasonic waves. Is preferred. The wiring is preferably taken out of the case by ultrasonic welding a through-type connector to the mounting hole of the case.
Preferably, the case is provided with an exhaust pipe for sealing gas.

A method of filling a gas having a density lower than that of the atmosphere into a confidential case in which a magnetic disk device is housed is performed by first reducing the pressure in the case and then filling a predetermined gas with a predetermined pressure. I can do things. Further, when the case is once depressurized, the case is placed in a heating chamber or the like and heated to about 80 ° C., so that oxygen and moisture to be removed from the case can be easily removed. Further, in order to improve the efficiency of replacing the gas to be sealed in the case, the operation of evacuation and filling of the predetermined gas can be repeated a plurality of times.

Next, a description will be given of a magnetic recording medium suitably used in the magnetic disk drive according to one embodiment of the present invention. As the substrate in the magnetic recording medium, for example, an Al alloy substrate containing Al as a main component, such as an Al-Mg alloy, a normal soda glass, an aluminosilicate glass, an amorphous glass, silicon, titanium, ceramics, various resins. Any substrate can be used as long as it is a non-magnetic substrate, such as a substrate made of such a substrate or a substrate obtained by combining them. Among them, the use of a glass substrate such as crystallized glass is preferable because the advantage that the mask means and the magnetic recording medium are not in contact is particularly utilized. In the manufacturing process of a magnetic disk, the substrate is usually washed and dried first, and in the present invention, it is preferable to perform washing and drying before formation from the viewpoint of ensuring the adhesion of each layer.

In manufacturing the magnetic recording medium of the present invention,
A non-magnetic metal coating layer such as NiP may be formed on the surface of the non-magnetic substrate. When the non-magnetic metal coating layer is formed, a method used for forming a thin film such as an electroless plating method, a sputtering method, a vacuum deposition method, and a CVD method can be used. In the case of a substrate made of a conductive material, it is possible to use electrolytic plating. The thickness of the nonmagnetic metal coating layer may be 50 nm or more. However,
In consideration of the productivity of the magnetic disk medium and the like, the thickness is preferably 50 nm or more and 500 nm or less. More preferably, it is 50 nm or more and 300 nm or less. The region where the non-magnetic metal coating layer is formed is desirably the entire region of the substrate surface. However, it is also possible to implement only a part, for example, only the region where the texturing is performed.

Further, concentric texturing may be applied to the surface of the substrate or the surface of the substrate on which the nonmagnetic metal coating layer is formed. In the present invention, concentric texturing is, for example, mechanical texturing using loose abrasive grains and texture tape or texturing using a laser beam, or by using these together, by polishing in the circumferential direction. This refers to a state in which a large number of microgrooves are formed in the circumferential direction of the substrate. The most preferred type of loose abrasive grains for mechanical texturing is diamond abrasive grains, especially those whose surfaces are graphitized. Alumina abrasive grains are widely used as abrasive grains used for mechanical texturing,
Particularly, from the viewpoint of an in-plane orientation medium in which the easy axis is oriented along the texturing grooves, diamond abrasives exhibit extremely good performance. Although the cause is not clear at present, extremely reproducible results have been obtained.

The surface of the substrate does not basically affect the effect of the present invention no matter what value the surface roughness (Ra) takes, but the fact that the head flying height is as small as possible is necessary for realizing high density magnetic recording. Is effective, and one of the features of these substrates is excellent surface smoothness.
a is preferably 2 nm or less, more preferably 1 nm or less, and particularly preferably 0.5 nm or less. However, the determination of Ra here is based on the case where measurement is performed using a stylus type surface roughness meter. At this time, the tip of the measuring needle has a radius of about 0.2 μm.

Next, an underlayer or the like may be formed on the nonmagnetic substrate between the nonmagnetic substrate and the magnetic thin film layer. The underlayer is used for the purpose of miniaturizing the crystal and controlling the orientation of the crystal plane, and a layer mainly containing Cr is often used. As a material of the underlayer containing Cr as a main component, in addition to pure Cr, Cr, V, Ti, Mo, Zr, Hf, Ta, W, and G are used for the purpose of crystal matching with the recording layer.
e, Nb, Si, Cu, B and the like to which second and third elements are added, and Cr oxide are also included. Above all, pure Cr and T
Those having i, Mo, W, V, Ta, Si, Nb, Zr and Hf are preferable. The content of the second and third elements varies depending on the respective elements, but is generally 1 atomic% to 50 atomic%, preferably 5 atomic% to 30 atomic%, more preferably 5 atomic% to 20 atomic%. Atomic% range. The film thickness of the underlayer may be sufficient as long as it can express this anisotropy, and is 0.1 to 50 nm, preferably 0.3 to 30 nm, and more preferably 0.5 to 10 nm.
nm. The substrate may or may not be heated during the formation of the underlayer mainly composed of Cr.

A soft magnetic layer may optionally be provided on the underlayer. In particular, a keeper medium having less magnetization transition noise or a perpendicular recording medium having magnetic domains perpendicular to the plane of the medium has a large effect and is often used. The soft magnetic layer is not particularly limited as long as it has a relatively high magnetic permeability and a small loss, and is optional.
iFe or a material obtained by adding Mo or the like as a third element thereto is often used. The optimum magnetic permeability greatly varies depending on the characteristics of the head used for writing data and the characteristics of the recording layer, but generally, the maximum magnetic permeability is 10 to 10,000,000.
(H / m). Next, a recording layer is formed, and a layer of the same material as the underlayer or another nonmagnetic material may be inserted between the recording layer and the soft magnetic layer. When forming the recording layer, the substrate may or may not be heated.

As the recording layer, a Co alloy magnetic film, TbF
A rare earth magnetic film represented by eCo, a transition metal / noble metal laminated film represented by a laminated film of Co and Pd, and the like are used. The Co alloy magnetic layer is usually made of pure Co or CoN.
i, CoSm, CoCrTa, CoNiCr, CoCr
A Co alloy magnetic material generally used as a magnetic material such as Pt is used. In addition to these Co alloys, Ni, Cr,
An element such as Pt, Ta, W, B or a compound such as SiO ₂ may be added. For example, CoCrPtTa, CoC
rPtB, CoNiPt, CoNiCrPtB and the like. The thickness of the Co alloy magnetic layer is arbitrary, but usually 5
５０50 nm, preferably 10-30 nm. Also,
The recording layer may be formed by laminating two or more layers via an appropriate non-magnetic intermediate layer or directly. At that time, the composition of the magnetic materials to be laminated may be the same or different.

The rare earth magnetic layer is usually made of TbFeC
o, rare earth magnetic materials generally used as magnetic materials such as GdFeCo, DyFeCo, and TbFe are used.
Tb, Dy, Ho, etc. are added to these rare earth alloys,
Ti or A for the purpose of preventing oxidation deterioration
1, Pt may be added. The thickness of the rare earth magnetic layer is arbitrary, but is usually about 5 to 100 nm.
The recording layer may be formed by laminating two or more layers via an appropriate non-magnetic intermediate layer or directly. At that time, the composition of the magnetic materials to be laminated may be the same or different. In particular, the rare earth magnetic layer is suitable for high recording density recording because the rare earth magnetic layer has an amorphous structure film and magnetization in a direction perpendicular to the media plane, and the recording of the present invention can be more easily applied.

As a laminated film of a transition metal and a noble metal, usually, Co / Pd, Co / Pt, Fe / Pt, Fe / Au,
A laminated film material generally used as a magnetic material such as Fe / Ag is used. The transition metal and the noble metal of these laminated films need not be particularly pure, and may be an alloy mainly containing them. The thickness of the laminated film is arbitrary,
Usually, it is about 5 to 1000 nm. The method of lamination is also arbitrary, and it is not always necessary to laminate two materials.

Generally, an arbitrary protective layer is formed on the recording layer, and then a lubricating layer is formed. As the protective layer,
Carbonaceous layers such as C, hydrogenated C, nitrogenated C, amorphous C, and SiC, and commonly used protective layer materials such as SiO ₂ , Zr ₂ O ₃ , and TiN can be used. The thickness of the protective layer is set at 50 to reduce the distance between the magnetic layer and the head.
nm or less, particularly preferably 30 nm or less. However, in order to obtain sufficient impact resistance, the thickness is preferably 1 nm or more. Further, the protective layer may be composed of two or more layers. It is preferable to provide a protective layer immediately above the magnetic layer with a layer containing Cr as a main component, since the effect of preventing oxygen from permeating the magnetic layer is high.

In the practice of the present invention, when the hermetic case is filled with an inert gas, the degree of oxidation of the magnetic layer is reduced, so that the protective layer may be thinned. Examples of the lubricant used for the lubricating layer include a fluorine-based lubricant, a hydrocarbon-based lubricant, a mixture thereof, and the like, and usually form the lubricating layer with a thickness of 1 to 4 nm.

The formation of a magnetic pattern on the magnetic recording medium is performed on the recording layer, and is usually performed by any of the conventional methods after forming the protective layer or the protective film and the lubricating layer. If there is no concern about oxidation of the recording layer, the treatment may be performed immediately after the formation of the recording layer. The method for forming each layer of the magnetic recording medium is arbitrary, and examples thereof include physical vapor deposition methods such as direct current (magnetron) sputtering, high frequency (magnetron) sputtering, ECR sputtering, and vacuum deposition. There are no particular restrictions on the conditions at the time of film formation, and the ultimate vacuum degree, substrate heating method and substrate temperature, sputtering gas pressure, bias voltage, and the like may be appropriately determined by the film formation apparatus. For example, in sputtering film formation, the ultimate vacuum degree is usually 5 × 10 ⁻⁶ To.
The substrate temperature is room temperature to 400 ° C., the sputtering gas pressure is 1 × 10 ^{−3 to} 20 × 10 ⁻³ Torr, and the bias voltage is generally 0 to −500 V. In forming the film, when heating the non-magnetic substrate, it may be performed before forming the underlayer, or when using a transparent substrate having a low heat absorption rate, Cr is mainly used to increase the heat absorption rate. A substrate may be heated after forming a seed layer or a base layer having a B2 crystal structure as a component, and then a recording layer or the like may be formed. When the recording layer is a rare earth magnetic film, the innermost and outermost parts of the disk are first masked to form a recording layer, and then a protective layer is formed from the viewpoint of preventing corrosion and oxidation. In this case, the mask is removed and the recording layer is completely covered with the protective film. If the protective layer is composed of two layers, the film is formed while the recording layer and the first protective layer are masked. It is preferable to remove the mask when forming the film, and to completely cover the recording layer with the second protective film because corrosion and oxidation of the rare earth magnetic layer can be prevented.

[0026]

EXAMPLES The present invention will be described below with reference to examples.
The present invention is not limited to the embodiments unless the gist is exceeded. FIG. 1 is a sectional view of a hard disk drive which is an embodiment of the information recording apparatus of the present invention. FIG. 2 is a cross-sectional view of a joint between upper and lower cases constituting the present drive, FIG. 3 is a cross-sectional view showing a structure of a spindle motor of the present drive, and FIG. 4 is a cross-sectional view showing a structure of a spindle motor shaft of the present drive. FIG. 5 is a sectional view showing the structure of the exhaust pipe of this drive.

First, a description will be given with reference to FIG. The disk 1 is mounted on a spindle motor 2 and reads and writes information while rotating at a speed of 10,000 revolutions per minute or more. Reading and writing of data on the disk 1 is performed by the flying head 3. The head 3 is provided only on the lower surface of the disk 1, and is attached to a rotatable pivot 5 via a head arm 4. On the opposite side of the head arm 4 of the pivot 5 is provided a voice coil 6 formed by resin-molding a wound copper wire. Voice coil 6
In a magnetic field formed by a voice coil actuator magnet 7 composed of a neodymium / iron / boron magnet, a thrust for moving the head 3 to the inner or outer periphery of the disk 1 is generated by energizing the coil.
The voice coil actuator magnet 7 is adhered to upper and lower yoke plates 8 fixed to upper and lower cases 16 by pins 12. Since the upper and lower yoke plates 8 strongly suck each other, the stays 9-1, 9-2, 9
The interval is maintained by -3. The rotating mechanism of the pivot 5 has a configuration similar to that of the spindle motor 2 described later, and has a configuration in which a means for generating a rotational force and a pinhole and a filter for air circulation are removed therefrom.

The yoke plate 8 is positioned not only by the pins 12 but also by the bush outer diameter of the pivot portion. A head ramp loading mechanism 10 is attached to the yoke plate 8 via a plate (mounting plate) 11, and the magnetic head 3 is retracted onto the ramp loading mechanism 10 when no power is supplied. The force for this is generated by a small ferrite magnet 19 provided outside the voice coil 6 and a leakage magnetic field of the voice coil motor magnetic field. When an airflow is generated inside the drive along with the rotation of the disk 1, a part of the airflow is guided to the voice coil 6 side by the rectifying unit 18 provided by pressing the upper and lower cases 16-1 and 16-2. The fluid resistance generated in the voice coil 6 generates a force for moving the head 3 to the inner peripheral side. This force and the force generated by the uniform force generating magnet 19 are set so as to be balanced at the rated rotation speed of the disk, and it is not necessary to supply an extra current to the voice coil 6 in order to cancel these forces. Another effect of inducing airflow in the voice coil portion is to efficiently cool the voice coil with a fluid. The air current flows intensively in the voice coil portion, takes the heat of the voice coil, transports it to the entire drive, and efficiently radiates heat from the entire case.

FIG. 3 shows details of the spindle motor. The spindle motor 2 generates a rotational force by an electromagnetic action of a spindle rotor 30 having a permanent magnet and a rotor yoke, and a spindle motor stator 31 formed by winding a copper wire around a laminated silicon steel plate. The rotor 30 is rotatably supported by the shaft 22 by bearings 28-1 and 28-2.
9-2 prevents oil mist generated from the bearings 28-1 and 28-2 from entering the inside of the drive. The outer periphery of the spindle motor 2 is concentric with the shaft 22 and polished smoothly, and the two disk fixing rings 32-1 and 32-3 pressed into this portion.
The disk 1 is fixed by 2-2. In the center of the disc 1, a center hole having a gap of about 50 μm from the outer diameter of the spindle motor is provided, and after the disc 1 is roughly centered, the lower fixed ring 32-1 Precise centering is performed by a Fresnel lens-shaped tapered portion h provided on the inner peripheral portion of the disk. Each of the fixing rings 32-1 and 32-2 is press-fitted after applying an adhesive to the inner periphery, and further, the adhesive is also applied to the disk-side surface of the upper fixing ring 32-2. The disk is firmly fixed to the spindle motor 2 by wiping the lubricant on the surface of the disk facing the disk with a nonwoven fabric containing an organic solvent and then pressing the wiper.

A small hole is provided in the upper side surface of the rotor 30 to allow the gas inside expanded by the heat generated by the motor 2 to escape.
2 has a similar hole. Further, a concave portion is provided inside the disk fixing ring 32-2, and a filter 33 is provided therein to prevent oil mist from entering the inside of the drive through this hole and allow only gas to pass. . When it is difficult to form a ring having a concave portion, two parts may be injection-molded and then used in combination. The shaft 22 of the spindle motor is hollow as shown in FIG. 4, and after inserting leads 23-1 to 23-3 for supplying electric power to the motor windings therein, the shaft 22 is filled with resin to maintain airtightness.

In this embodiment, the entire drive is housed in an airtight case 16. The shape of the case is larger than that of a traditional square case having a flat partition wall, as shown in FIG. 1, in order to have strength enough to withstand the reduced pressure or positive pressure for replacing the gas inside. It is preferable that the partition has an oval shape formed of a curved surface.
This shape is also preferable in that the filling gas can be saved. The case 16 comprises an upper case 16-1 and a lower case 16
-2, consisting of two cases of almost the same shape, each case is formed by press-molding a thick aluminum plate, and several parts are press-fitted and welded or glued in a state where positional accuracy is secured by a jig After mounting, the parts requiring surface accuracy are machined and finally washed thoroughly to remove deposits. FIG. 2 shows the joint between the upper and lower cases. The joint portion of each case has a brim portion, and the joining surfaces a-1 and a-2 are flattened by machining and subjected to groove processing for improving airtightness.

After the components constituting the drive are mounted inside the case, the upper and lower cases are pressed against the joints a-1 and a-2 with the resin sheet 20 interposed therebetween, and ultrasonic waves are actuated. Is welded to both joining surfaces to obtain airtightness, and then the brim portion is caulked as indicated by b to obtain a mechanically strong connection. The disk 1 has a recording layer, a protective layer, and other films provided on a substrate having protrusions corresponding to servo patterns in advance. The substrate having the projections is made by injection molding of a resin using a stamper. Aluminum is first deposited on the substrate, and then a soft magnetic layer mainly composed of nickel having a thickness of about 20 μm is formed by electroplating, and this is polished with a fixed grindstone to Ra 0.5 nm or less. Polish to a flat roughness. After the thus obtained smooth substrate is washed and dried, a TbFeCo magnetic layer and a carbon protective layer are formed by magnetron sputtering. If necessary, a layer for controlling magnetic properties may be provided below the magnetic layer, or a layer of chromium or the like may be provided between the carbon protective layer and the magnetic layer in order to strongly protect the magnetic layer. A protective layer may be added. A lubricant is finally applied to the disk thus obtained, and the lubricant is firmly adhered to the disk surface by heating or ultraviolet irradiation.

The servo pattern is formed by providing a projection locally on the resin substrate. The soft magnetic layer in this portion is removed by polishing or the like, and the recording characteristics in this portion are degraded as compared with others. When a short-wavelength signal is written on the entire surface, insufficient writing is performed on a portion corresponding to the servo pattern, and a weak signal portion is formed. Head position control is performed by detecting this weak signal portion. The short-wavelength signal can be efficiently written in a short time by using a wide head and writing with a high-frequency signal synchronized with rotation. Further, by reading this signal using an inspection head, a defect inspection of the medium is also performed in parallel.

Next, a method of assembling the present drive will be described. First, the upper case 16-2 and the lower case 16-1 are formed by press working. Next, the spindle motor mounting portion and the pivot mounting portion bushings are press-fitted into the case in a state where they are mounted on a jig for which positional accuracy is secured in advance, and airtightness and mechanical strength are maintained by welding, bonding, or caulking. Further, a hole for attaching an exhaust pipe is formed in the case, and the exhaust pipe is attached. A stay (not shown) having a tapped hole for attaching the yoke plate fixing pin and the circuit board and attaching the drive itself to a personal computer or the like is attached by welding. Further, the welding surfaces of the connector mounting hole and the upper and lower case joints are processed, and the connector is mounted on the case by ultrasonic welding. The spindle unit, that is, the spindle motor and the disk are assembled in advance, and only this part is tested independently. The head unit, that is, the pivot, the head, and the voice coil motor are similarly assembled in advance, and the characteristics of this part alone are checked.

Next, to the pins 12 of the lower case 16-1,
The yoke plate 8 to which the magnet 7, the stay 9, and the lamp loading mechanism are adhered is inserted into a pin, and is fixed by means such as press-fitting, bonding, and caulking. Next, the shaft of the head unit is pressed into the bush, and the lead portion of the flexible board is inserted into the connector. At this time, the head is retracted to the ramp loading mechanism. Next, the spindle unit is pressed into the bush. Subsequently, a resin sheet is placed on the joint of the upper and lower cases, and the upper case to which the yoke plate and the magnet are previously attached is pressed, and the spindle and the pivot shaft are pressed into the two bushes of the upper case. Next, an ultrasonic horn is pressed against the upper and lower case joints to perform ultrasonic welding. In addition, the upper and lower case joints are caulked while applying force from above and below, and the two cases are firmly joined.

Next, an operation for filling the inside of the drive with low-pressure helium gas is performed. Commercially available helium gas can be used. For example, 6 Nine helium gas manufactured by Taiyo Oxygen (oxygen content: 0.1 ppm or less, moisture content: 0.5 ppm or less), 6 Nine Helium gas manufactured by Nippon Oxygen (oxygen content: 0.0
5 ppm or less, dew point -80 ° C. or less) is suitably used. First, put the whole drive into the heating chamber,
C. and the exhaust pipe is connected to a gas filling device. Next, the inside of the drive is evacuated and kept for a certain time to remove oxygen and moisture adsorbed inside. Next, helium gas is charged, and the inside is re-evacuated to completely remove the oxygen gas and moisture therein. Finally, helium gas is filled. After the above operation is completed, the exhaust pipe 17 is crushed as shown in FIG. 5 and the exhaust path is closed. Then, the exhaust pipe is removed from the gas filling device. keep. The filler is preferably a material having flexibility and environmental resistance. For example, a resin, a low-melting metal, a low-melting glass, or the like can be used. Finally, the circuit board is attached, and the product inspection is performed to complete the hard disk drive. The drive obtained in this way has a low gas density in the drive and a low Reynolds number of the surrounding gas even under high-speed rotation, so that the vibration of the medium is suppressed and the drive is high even for a resin substrate with poor rigidity. Operation is possible with the number of revolutions of the spindle.

Further, by using an inert gas as the gas to be filled, the medium is not exposed to oxygen and moisture, so that a TbFeCo magnetic layer having excellent magnetic properties can be used. Since the resin substrate has a low heat-resistant temperature, it is necessary to form the magnetic layer at a low temperature.
Although it was difficult to obtain a high coercive force with the magnetic layer, Tb
The FeCo magnetic layer also has a feature that high magnetic properties can be obtained even at a low temperature film formation, and a magneto-optical disk which is a medium having a TbFeCo magnetic layer put into practical use today generally uses a polycarbonate substrate which is a resin material. Manufactured. In addition, the resin substrate has an advantage that a high-precision surface can be obtained at a low cost, a servo pattern can be easily formed using a stamper, and a Fresnel lens type taper portion for centering can be formed at the same time. There is. In practicing the present invention, it is necessary to house the drive in an airtight case. However, since the hard disk drive is originally housed in a sealed case to avoid the inflow of dust, in the present invention,
It is only necessary to increase the strength of the case to withstand reduced pressure or positive pressure. Furthermore, the case of the hard disk drive is still made of aluminum die-casting to ensure mechanical accuracy, and an increase in strength does not lead to a significant increase in cost. In addition, the technology for sealing the container is a technology widely used today, such as a light bulb, a vacuum tube, a can, a Freon refrigerator, a gas cylinder, and the like.
It can be implemented easily and inexpensively with existing technology.

[0038]

According to the present invention, it is possible to solve the problems of windage, vibration, noise, etc. in a high-speed rotation type information recording apparatus without using such a special recording medium or a small head. An information recording device with a high transfer speed can be provided at low cost.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of an information recording apparatus according to the present invention.

FIG. 2 is a cross-sectional view of a case joining portion of an embodiment of the information recording apparatus of the present invention.

FIG. 3 is a cross-sectional view showing the structure of a spindle motor according to an embodiment of the information recording apparatus of the present invention.

FIG. 4 is a cross-sectional view showing the structure of a spindle motor shaft according to an embodiment of the information recording apparatus of the present invention.

FIG. 5 is a cross-sectional view showing a structure of an exhaust pipe of an embodiment of the information recording apparatus of the present invention.

[Explanation of symbols]

 Reference Signs List 1 disc 2 spindle motor 3 head 4 head arm 5 pivot 6 voice coil 7 voice coil actuator 8 yoke plate 9 stay 10 ramp load mechanism 11 mounting plate 12 pin 13 flexible board 14 penetrating connector 15 head amplifier 16 case 17 exhaust port 18 rectifying section 19 Uniform Force Generating Magnet 20 Resin Sheet 21 Bush 22 Spindle Motor Shaft 23 Motor Lead 24 Plug 25 Lead Pin 26 Connector Piece 27 Filler 28 Bearing 29 Magnetic Fluid Seal 30 Spindle Rotor 31 Spindle Motor Stator 32 Disk Fixing Ring 33 Filter

Claims (6)

[Claims] 1. A recording medium, a driving unit for driving the recording medium in a recording direction, a head having a recording unit and / or a reproducing unit, and a unit for relatively moving the head with respect to the recording medium;
What is claimed is: 1. An information recording apparatus comprising: a recording / reproducing signal processing unit for inputting a recording signal to a head and outputting a reproduction signal from the head, wherein at least a recording medium, a driving unit, a head, and a relative moving unit are hermetically sealed. An information recording apparatus, wherein the density of the gas inside the case is kept lower than that of the atmosphere. 2. The information recording apparatus according to claim 1, wherein the recording medium is rotated to perform recording and / or reproduction by a head, and the number of rotations is 10,000 rpm or more. 3. The information recording apparatus according to claim 1, wherein the pressure inside the case is kept lower than the atmospheric pressure. 4. The information recording apparatus according to claim 3, wherein the pressure inside the case is 0.1 to 0.9 atm at room temperature. 5. The information recording apparatus according to claim 1, wherein the case is filled with a gas having a smaller molecular weight than the atmosphere. 6. The information recording apparatus according to claim 5, wherein the case is filled with helium gas.