JPS6013371A - Magnetic disc device - Google Patents

Abstract

PURPOSE:To suppress the evaporation of a lubricating film on the surface of a magnetic disc in rotating in a sealed type magnetic disc device by forming the inner wall surface of an air-tight storage case coated with an evaporation source lubricating film like a rough surface or a porous surface. CONSTITUTION:The inner wall surface 9 worked like a tongued and grooved rough surface or a porous surface of the air-tight storage case 8 sealing the magnetic disc 1 on a base part 11 is coated with the evaporation source lubricating film 10 obtained by adhering a lubricating agent consisting of stearic acid generating vapor at 60-70 deg.C. The lubricating agent vapor generated by the high speed rotation of the magnetic disc 1 is made flow from upper and lower directions into a center air hole 3 of a hab mechanism part 2 together with hot air flow and flow out from an small air hole 4 into a part between respective discs 1 and is repeatedly circulated in the air-tight storage case 8 so as to surround the magnetic disc 1. Therefore, the vapor pressure generated when the lubricating agent on the surface of each magnetic disc in rotating is approximately equilibrated with the vapor pressure of circular lubricating agent vapor surrounding the lubricating film on the surface of each magnetic disc 1 and always good lubricating characteristics can be maintained.

Description

Detailed Description of the Invention +a+ Technical Field of the Invention The present invention relates to a magnetic disk device, and more particularly, to the thickness and lubrication properties of a lubricating film coated on the surface of a magnetic disk mounted in the device. The present invention relates to a device configuration that can always maintain a steady state.

BACKGROUND OF THE INVENTION In recent years, in magnetic disk drives, attempts have been made to increase the recording density by thinning the magnetic film of the magnetic disk, lowering the flying height of the magnetic head, and so on. In addition to the above-mentioned lower flying height of the magnetic head, the magnetic head is in contact with the surface of the magnetic disk when stopped, and as the rotation speed increases, the magnetic head is slightly floated.
As the 3S (Contact 5Tart 5Top) method is increasingly adopted, it becomes easier for the magnetic head and magnetic disk surface to suffer wear and damage due to contact sliding when starting and stopping rotation.In order to prevent this, It is common practice to apply special surface treatment such as applying a lubricant to the surface of a magnetic disk or coating it with a lubricant film.

fcl Prior Art and Problems By the way, as the recording density of magnetic disk devices increases, lowering the flying height of the magnetic head becomes more and more important, and the lubricating film applied to the surface of the magnetic disk is gradually becoming thinner. An extremely thin lubricating film with excellent lubrication durability is required before and after the person.

On the other hand, magnetic disk drives are increasingly becoming sealed types in order to prevent head crashes caused by contamination with dust. However, in such a sealed magnetic disk device, the temperature inside the sealed device rises due to air friction (windage damage) caused by the high speed rotation of the magnetic disk, so the internal atmosphere is usually Cooling is performed using a circulating air cooling system, but depending on the usage conditions, the temperature may still exceed 6.
An increase in temperature of 0 to 70 degrees Celsius is unavoidable, and this temperature increase causes the inconvenience that the lubricating film applied to the surface of the magnetic disk evaporates and disappears, degrading its lubricating properties. There is also a strong demand for a lubricating film with excellent heat resistance that can eliminate these problems.

By the way, in response to these various demands, conventional magnetic disk surfaces are not moisturized. r! Typical lubricants used to form a film include hydrocarbon-based lubricants such as paraffin, higher alcohols, higher fatty acids, and esters of higher fatty acids, and their fluorides, such as fluorocarbons. There are solid lubricants made of molybdenum disulfide, tungsten disulfide, graphite, graphite fluoride, etc., which can be used singly or in combination. It is used in

Among the above lubricants, hydrocarbon-based lubricants, especially the lubricating film formed by higher fatty acids and their esters, have excellent lubricating properties and are effective in improving lubrication durability. On the other hand, it has the disadvantage of poor heat resistance, such as gradual evaporation and loss of lubricity in a high-temperature atmosphere of 60 to 70°C. Furthermore, lubricating films formed from fluorocarbon oils, silicone oils, and the like have excellent heat resistance but poor lubricating properties. Furthermore, since solid lubricants such as molybdenum disulfide are in the form of fine powder, they are generally used in combination with liquid or semi-solid grease-like lubricants, but the particle size of the lubricants is on the order of microns. Therefore, it is difficult to make a thin film.

Therefore, it is not only difficult to obtain an ultra-thin lubricant film with excellent lubrication durability and heat resistance for high recording density, but also a magnetic disk coated with such a lubricant film to be used as a sealed magnetic disk. When used in devices, head crash problems were inevitable, making it difficult to perform high-density recording or reproduction.

(d) Purpose of the Invention In view of the above-mentioned conventional circumstances, the present invention is based on the principle that a substance under evaporation conditions does not evaporate in an atmosphere of saturated vapor of the substance, and is based on the principle that a substance under evaporation conditions does not evaporate in an atmosphere of saturated vapor of the substance. The object of the present invention is to provide a novel magnetic disk device capable of suppressing evaporation and loss of a lubricant film on the surface of a magnetic disk during rotation and maintaining the lubricant film in a steady state with good lubrication properties at all times. be.

(e) Structure and object of the invention According to the present invention, in a magnetic disk device configuration in which a magnetic disk whose surface is coated with a lubricating film is sealed in an airtight housing lid, the inner wall surface of the airtight housing lid is sealed. An evaporation source lubricating film that evaporates as the temperature rises inside the housing lid is attached thereto, and the inner wall surface of the airtight housing lid provided with the evaporation source lubricating film has a rough or porous surface shape. This is achieved by providing a magnetic disk device characterized by:

ff) Embodiment of the Invention An embodiment of the present invention will be described in detail below with reference to the drawings.

The figure is a sectional view of a main part conceptually showing such an embodiment. In the figure, 1 is a magnetic disk formed by coating the front and back surfaces with a lubricant film (not shown) about 100 mm thick using a lubricant made of stearic acid, which is a type of higher fatty acid, and 2 is a magnetic disk made of a plurality of magnetic disks. A hub mechanism unit integrally supports the magnetic disk 1 and is attached to the rotating shaft 6 of the disk rotation drive mechanism 5, 3 is a center ventilation hole of the hub mechanism unit 2, and 4 is in communication with the center ventilation hole 3. These are small ventilation holes that allow circulating atmosphere to flow out between the magnetic disks 1. A filter 7 is attached to the inner wall surface of the central ventilation hole 3 so as to cover each of the small ventilation holes 40. Further, reference numeral 8 denotes an airtight housing lid body that seals the magnetic disk 1 on the base portion 11, and the inner wall surface 9 of the lid body is processed to have an uneven surface or a porous surface, for example. That is, in this embodiment, an evaporation source lubricant film 10 is attached to the rough inner wall surface 9, which is made by depositing a lubricant made of stearic acid, which generates vapor at a temperature of 60 to 70° C., by a vapor deposition method or the like. has been done.

The reason why the inner wall surface 9 of the airtight housing lid 8 is made to have an uneven rough surface shape or a porous surface shape is as follows. f! This is to improve the adhesion of agent I and to widen the adhesion area to increase the amount of adhesion and the amount of evaporation. In addition, in FIG. 5, in order to simplify the explanation, the magnetic head, head actuator, etc. whose configuration is not particularly different from the conventional one are omitted.

As mentioned above, the airtight storage lid 8 in the magnetic disk device
By attaching the evaporation source lubricating film 10 to the inner wall surface 9 of the magnetic disk 1, the hot air flow whose temperature has increased due to air friction (windage loss) caused by the high speed rotation of the magnetic disk 1 can be kept airtight as shown by the arrow in the figure. The lubricant circulates along the inner wall surface 9 of the housing lid 8 and heats the evaporation source lubricant film 10 attached to the inner wall surface 9 to generate lubricant vapor. The generated lubricant vapor flows from above and below into the center ventilation hole 3 of the hub mechanism section 2 together with the hot air flow, passes through a filter 7, and removes dust such as lubricant, large particles of moisturizing agent vapor, etc. Clean lubricant vapor flows out between the magnetic disks 1 through the communicating small ventilation holes 4 and is repeatedly circulated within the airtight housing cover 8 so as to surround the magnetic disks 1. At this time, the temperature inside the airtight housing lid 8 is about 60 to 70°C.

Is there any moisture on the surface of each rotating magnetic disk? F! The vapor pressure when the i-film evaporates due to a temperature increase due to air friction during high-speed rotation and the vapor pressure of the circulating lubricant vapor surrounding the lubricant film on the surface of each magnetic disk 1 are approximately in equilibrium, The lubricating film on the surface of each of the rotating magnetic disks 1 can be easily maintained in a steady state in which it always has good lubrication properties. By the way, the conventional evaporation source Jun? If there is no fk film, magnetic disk 1 can be removed by CSS operation after 50 hours.
On the other hand, when the magnetic disk 1 was rotated at high speed in a lubricant vapor atmosphere as described above, Even after 200 hours, no head crashes such as scratches were observed on the surface of the magnetic disk 1 in the CSS 11 magnetic head, and the coefficient of friction of the lubricant film on the surface of the magnetic disk 1 was 0. It had good lubricity of .20 to 0.24. This result shows that the former shows that the lubricating film on the surface of the magnetic disk 1 has been scattered and disappeared, while the latter shows that it is maintained.

In the above embodiment, the lubricant is applied not only to the front and back nine surfaces of the magnetic disk 1 in the airtight container 7 but also to other functional parts. The ik membrane is extremely thin and does not particularly impair the functionality of the device. The lubricant used to form the evaporation source lubricant film 10 on the inner wall surface 9 of the airtight housing structure 8 may be the same material as the lubricant film coated on the front and back surfaces of the magnetic disk 1, as described in this embodiment. It is not limited to stearic acid. For example, a similar effect can be obtained when using a lubricant made of myristic acid, palmitic acid, behenic acid, or cerotic acid.
! 7. Furthermore, it goes without saying that higher aliphatic alcohols and higher fatty acid esters can also be used, as well as fluorinated oils such as Krytox manufactured by Du Pont.
Similar effects were observed using 143AD.

Other methods for depositing and forming the evaporation source lubricant film 10 on the inner wall surface 9 of the airtight housing lid 8 include a brush coating method, a spray method,
This can be carried out by various methods such as dipping.

(Effects of the Invention) As is clear from the above explanation, the structure of the magnetic disk device according to the present invention has a simple improved structure that coats the surface of the magnetic disk that is being rotated in the sealing device. Evaporation loss of the lubricant film is easily suppressed, and the ?rI
J-peritoneal film thickness and ? It has the excellent advantage of being able to always maintain the rR slip characteristics in a good steady state. Therefore, it is necessary to lower the flying height of this type of magnetic disk device, especially the magnetic head.
It is extremely advantageous to apply it to sealed magnetic disk devices that employ the CSS method or the like.

[Brief explanation of the drawing]

The drawing is a sectional view of a main part conceptually showing an embodiment of a magnetic disk device according to the present invention. In the drawing, ■ indicates a magnetic disk coated with a lubricating film;
2 is a hub mechanism, 3 is a center ventilation hole, 4 is a small ventilation hole, 5 is a rotational drive mechanism, 6 is a rotating shaft, 7 is a filter, 8 is an airtight housing lid, 9 is an inner wall surface of the airtight housing lid 8 , 10 is an evaporation source lubricating film, and 11 is a base portion. 1]

Claims (1)

[Claims] (1,1 In a magnetic disk device in which a magnetic disk whose surface is coated with a lubricating film is sealed in an airtight storage lid,
A magnetic disk drive characterized in that an evaporation source lubricant film is attached to the inner wall surface of the airtight housing lid, which evaporates as the temperature inside the housing lid increases. (2) Claim 1, characterized in that the inner wall surface of the airtight housing lid to which the evaporation source lubricating film is attached is rough.
The magnetic disk device described in . (3) The magnetic disk device according to claim 1, wherein the inner wall surface of the airtight housing lid to which the evaporation source lubricating film is attached is porous.