JPH052864A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To provide the magnetic disk device which prevents the contact of a magnetic disk having a carbon protective film with a magnetic head, the combustion of the oxygen in the air and the carbon by reaction with each other and the consequent chemical wear of the disk. CONSTITUTION:Vent holes 6, 8 for continuously introducing an inert gas, such as nitrogen or argon, without contg. oxygen into the disk device are provided in this device. The wearing rate of the carbon protective film of the magnetic disk is drastically lowered and the market life as the magnetic disk device is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk device having a carbon-based protective film.

[0002]

2. Description of the Related Art A carbon protective film is burned by oxygen in the air and the contact heat generated between a head and a disk to form carbon dioxide gas, which disappears, that is, is chemically worn.

Therefore, it was devised to reduce the wear rate and extend the life of the device by eliminating oxygen from the inside of the magnetic disk device. As disclosed in Japanese Patent Application No. 1-239945, Fujisawa and Nakagawa et al.
The inventor has invented to use an inert gas sealed.

[0004]

SUMMARY OF THE INVENTION In the above prior art,
Since the basic essence of the invention is to seal the inert gas in the disk device, there is a problem that a pressure adjusting mechanism must be provided in order to absorb the pressure difference between the inside and outside of the disk device. That is, the existence of the pressure regulator has been a problem in making the disk device compact and reducing the cost. In addition, the consideration has not been given sufficiently to the organic gas and water generated from the components in the disk device.

The first object of the present invention is to block oxygen and suppress combustion of the carbon protective film, that is, chemical wear. An object of the present invention is to provide a structure of a magnetic disk device that solves the problems at the same time.

[0006]

In order to achieve the above-mentioned object, the main point devised in the present invention is to prevent the infiltration of oxygen (air) by continuously flowing an inert gas into the disk device.

That is, the disk device is not an airtight type but an open type, and basically has a structure in which gas can flow in and out of the device through two ventilation holes.

However, as it is, since oxygen flows into the apparatus through the vent hole, one vent hole (gas inlet port)
Allow more inert gas to flow, the other vent (gas outlet)
The structure will allow more gas to be discharged.

As a result, by introducing an inert gas into the inside of the disk device, which was filled with air at the time of assembling and manufacturing the disk device, for a necessary and sufficient time prior to actual use, the oxygen in the inside was changed by the inert gas. Will be replaced.

After that, by continuing to flow the required amount of inert gas, backflow of air from the outlet cannot occur and the inside of the disk device can be kept in anoxic state.

Nitrogen gas is preferable because the inert gas as used herein means that it does not contain oxygen. Other than that, helium, neon, argon, and krypton are conceivable, but the gas is more expensive than nitrogen but can be used.

By introducing an inert gas,
Since there is a risk that fine particles in the gas may enter the apparatus and trigger a head crash, it is effective to provide a filter for particles at the inlet and the outlet.

Further, moisture and organic gas contained in the introduced gas and penetrating it have an adverse effect on the life of the disk device and are therefore preferably removed. Therefore, it is effective to install an activated carbon filter for adsorbing organic gas on the inlet side and a desiccant pack made of silica gel or the like for adsorbing water to highly purify the introduced gas.

[0014]

The carbon protective film is categorized into two types, that is, mechanical wear and chemical wear. The chemical abrasion is a phenomenon in which oxygen and carbon in the air react with each other at a high temperature and become carbon dioxide gas (CO ₂ ) and disappear.

It is clear from our experiments that the life of the carbon protective film can be dramatically improved by suppressing the chemical abrasion.

The use of oxygen-free inert gas in the magnetic disk device according to the present invention has the effect of dramatically improving the sliding resistance of the magnetic disk device.

For this purpose, the hermetically sealed disk device is required instead of the conventional hermetically sealed type, instead of the conventional hermetically sealed type. Since the gas pressure adjusting mechanism is unnecessary, the apparatus can be made compact and simplified, and the manufacturing cost can be reduced. The present invention requires an inlet and an outlet for an inert gas and a filter for particulates in the gas accompanying the inlet and the like. However, compared with the pressure adjusting mechanism of the conventional invention, it is much simpler and lower in cost.

However, according to the present invention, a new management and maintenance cost for supplying high-purity nitrogen gas is newly incurred, which significantly improves the life of the disk device and reduces the device cost. It is clear that the method of the present invention is superior overall, considering that it can be reduced.

If the introduced gas continues to flow in and out at a certain speed, various kinds of organic gas and moisture, which are generated over time from various parts of the disk device and adversely affect the life of the device, are forced out of the device. There is also an effect. Therefore, the reliability life of the magnetic disk device can be improved.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a sectional view of the magnetic disk device.

Magnetic disk 1 of 5.25 "in which a fluoropolyether is applied as a lubricant on a carbon protective film 1.
Uses a Co-Cr-Ta film as the recording film, and uses a Ni-P film formed on an AL alloy as the substrate. As the carbon film, one formed by a sputtering method or a CVD method is used. Even if the carbon film contains a trace amount of hydrogen or an additive element, it does not defeat the purpose of the present invention.

The rotating spindle of the disk is 2, which is rotated at high speed by the motor 7. The magnetic head 3
It is directly connected to the carriage body 5 via the guide arm 4. The entire carriage moves horizontally in this figure to access the magnetic head.

Of most relevance to the present invention are the gas vents shown at 6,8. There are two, one is the inlet 8
And the other is the outlet 6. Reference numeral 9 is a fine particle filter placed in the vicinity of the gas vent hole. This traps particles existing in the supplied inert gas and prevents the head disk from crashing due to dust.

An activated carbon filter 10 and a silica gel desiccant pack 11 were installed in the gas passage on the gas introduction port side to gradually remove the organic gas and water present in the introduced gas.

When the inert gas is introduced into several units, the first outlet and the second inlet may be connected in series. In this case, in order to prevent the particles, organic gas, and water generated in the first device from being introduced into the second device as they are, the above-mentioned activated carbon filter, desiccant, and gas flow path are used. It is effective to install it in and to purify the gas. It is also preferable to install the three in the order of this embodiment.

Of course, it is also possible to use a method in which the gas paths of several units are supplied in parallel instead of connected in series.

Next, an embodiment in which the magnetic disk device according to the present invention is actually used will be described.

A magnetic disk device was assembled in a clean room inside a factory by a usual method, inspected, and shipped. At the time of shipment, the inside of the magnetic disk device is filled with normal dust-free clean air, and the vent hole is provided with a cap to prevent entry and exit from external air.

After the magnetic disk device is installed at the place of use, for example, in a computer room, the purity is 99.9 at the gas inlet side.
The 9% nitrogen gas line was connected using SUS piping or Teflon tube. Connect the gas line to the outlet side,
The other end was connected to an indoor exhaust duct and exhausted outdoors.

Prior to using the magnetic disk, high-purity nitrogen gas was introduced at a flow rate of 1 L / hour for a day and night. In this case, since the space volume in the disk device was about 800 mL, the air originally present could be completely replaced with pure nitrogen during the day and night.

After that, the use of the magnetic disk was started.
At this time, the flow rate of nitrogen gas supplied to the device is 100 m / hr.
Set to L.

The flow rate of the nitrogen gas supplied to the magnetic disk device which has entered the continuous use stage is 100 mL / in this embodiment.
However, it is not necessary to limit to this flow velocity. In our experience, it has been found that about 10 mL / hour to 500 mL / hour is preferable. If the amount of inflowing gas is too small, it is difficult to control the gas flow velocity, there is a possibility that backflow from the discharge port may occur, and there is a problem that the effect of expelling organic gas and moisture generated in the device is reduced.

On the other hand, if the flow velocity is too high, the life of the particle filter, the activated carbon filter and the desiccant becomes short, and the material cost of the used gas increases, which is disadvantageous. Therefore, it is necessary to set the flow velocity in the optimum range, but since there are various magnetic disk devices having different sizes and capacities, it is important to set the value according to each.

Generally, the organic gas and moisture generated in the apparatus are large for a while after the start of operation of the magnetic disk. For this reason, for several months after the start of operation, increasing the gas flow rate to increase the gas replacement efficiency and decreasing the gas flow rate as the inside of the device is exhausted shortens the life of the device. Of course, it is also convenient to increase.

The nitrogen gas introduced into the disk device is the temperature of the chamber in which the disk device is installed in advance at 23 ° C. ± 1.0.
It was introduced after adjusting to. If there is a large temperature difference from room temperature, problems will occur on both the low temperature side and the high temperature side. Furthermore, nitrogen gas is usually introduced from a gas cylinder or an outdoor liquid nitrogen tank, but between the supplier and the disk unit,
It is also possible to provide a dedicated particle filter, activated carbon filter, and desiccant. The essence of the invention is to purify the gas to be introduced and to make it highly purified, and the place of installing a filter or the like for that purpose is secondary. Of course, the gas after passing through the filter equipment dedicated to the supply gas line and the adsorption equipment may be further introduced into the filter, the activated carbon, and the apparatus containing the desiccant as in the present invention.

Further, an oxygen absorber may be added in addition to the desiccant, activated carbon and filter of the present invention. In this embodiment, 99.99% nitrogen gas was used as the inert gas to be introduced, but higher purity nitrogen gas may of course be used. However, the purity is too low, for example, 99% level, the rest is 1%
In the case of the above oxygen, a small amount of oxygen caused chemical abrasion of the carbon protective film, that is, combustion, and the abrasion rate of the protective film was clearly increased as compared with the use of high-purity gas. Therefore, the inert gas has a purity of about 99.9% or more, that is, an oxygen concentration of 0.1, although it depends on the flow rate of the gas.
% Or less is desirable.

Although high-purity nitrogen gas was used in this embodiment,
In addition to this, even if 99.9% Ar gas, helium gas, neon gas, and krypton gas of the same purity were used, it was possible to confirm the same high level as in the present invention.

Further, even if two or more kinds of the above gases are mixed and used, the purpose of the present invention is not impaired.

According to the present invention, it is possible to prevent the phenomenon that the carbon protective film reacts with oxygen and burns to be chemically worn. Therefore, the wear rate of the carbon protective film can be reduced by 1 to 2 digits or more as compared with the wear rate in the atmosphere.
However, even without oxygen, the phenomenon of mechanical wear by the magnetic head occurs, and the wear rate cannot be zero. Also, because the combustion characteristics differ depending on the carbon film quality,
The reduction effect has a width of 1 to 2 digits or more.

As described above, since the wear rate of carbon can be greatly reduced, the factory life of the magnetic disk device can be greatly increased.

For example, when the life of the apparatus is examined by a CSS test in the atmosphere, the fluctuation of the electric output and the increase of the spindle rotation driving torque become remarkable when the average CSS number is about 30k. At this time, when the surface of the disc is observed in detail using SEM or the like,
It was confirmed that carbon abrasion occurred.

On the other hand, according to the present invention in which 99.99% of nitrogen gas shown in the embodiment is introduced, according to the present invention, the number of CSS times is 200 k.
Even after the rotation, the output fluctuation and the torque increase at the start of rotation were not observed, and the wear of the carbon surface was extremely slight. As a result, the present invention dramatically improves the market life of the disk device and enables stable driving.

According to the present invention, at the same time, the organic gas and the water generated from the internal parts of the apparatus are gradually removed, so that the adhesion of the head / disk due to the organic gas is prevented from adhering and the water is prevented from corroding the metal thin film medium. It also has the effect of. Together with the above-mentioned suppression of carbon wear, it has the effect of improving the life reliability of the disk device as a whole.

Introducing a gas near room temperature is also effective for cooling the apparatus.

[0045]

According to the present invention, a pressure adjusting mechanism for maintaining the inside and outside of the apparatus, which is required in the conventional hermetically sealed disk apparatus, is unnecessary, and instead, a simple gas inlet nozzle and a gas product level are provided. A filter and an adsorbent are required. Therefore, the manufacturing cost of the device can be reduced by 7% compared to the conventional method.
Moreover, there is an effect that the apparatus volume can be reduced by 5%. It contributed to low price and compactness.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a magnetic disk device showing an embodiment of the present invention.

[Explanation of symbols]

1 ... magnetic disk, 2 ... Rotating spindle, 3 ... magnetic head, 4 ... Head guide arm, 5 ... Carriage, 6 ... gas exhaust port, 7 ... rotary motor, 8: Gas inlet, 9 ... filter, 10: Activated carbon filter, 11 ... Desiccant pack (silica gel), 12 …… Control / signal system circuit board.

Claims (4)

[Claims] 1. A magnetic disk comprising a protective film containing carbon as a main component, a lubricating film formed thereon, a metal magnetic film, and a substrate, a magnetic head, a disk and a rotation and drive mechanism for the head. In a magnetic disk device comprising
A magnetic disk device having a structure in which oxygen does not enter the disk device and cannot exist therein by continuously supplying an inert gas containing no oxygen into the magnetic disk device. 2. A magnetic disk device according to claim 1, wherein an inlet and an outlet for the inert gas are provided, and while the inert gas is introduced through the inlet, the inert gas is continuously discharged through the outlet. 3. A magnetic disk device according to claim 1, wherein a mixed gas of one or more kinds selected from nitrogen, helium, neon, argon and krypton is used as the inert gas. 4. A magnetic disk device according to claim 2, wherein a particulate filter, an activated carbon filter and a desiccant pack are provided on the inlet side and a particulate filter is provided on the outlet side.