JPH0121559B2 - - Google Patents

Description

Detailed Description of the Invention (a) Technical Field of the Invention The present invention relates to a method for stabilizing a lubricant film on the surface of a magnetic disk, and particularly to a method for stabilizing a lubricant film on the surface of a magnetic disk during rotation in a sealed magnetic disk device. The present invention relates to a stabilization method capable of constantly maintaining lubrication properties in a steady state.

(b) Background of the Technology In recent years, in magnetic disk devices, attempts have been made to increase the recording density by making the magnetic film of the magnetic disk thinner or multilayered, and lowering the flying height of the magnetic head. In addition to lowering the flying height of the magnetic head, the magnetic head is in contact with the surface of the magnetic disk when stopped, and as the rotational speed increases, the magnetic head is slightly raised.
As the so-called CSS (Contact Start Stop) method is increasingly adopted, head crushing such as wear and damage on the surface of the magnetic head and magnetic disk is likely to occur due to contact sliding when starting and stopping rotation. It is common practice to apply special surface treatments such as applying a lubricant to the disk surface or coating it with a lubricant film.

(c) 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. requires an extremely thin lubricant film of around 100Å with excellent lubrication durability. On the other hand, with the adoption of the above-mentioned CSS method, magnetic disk devices are being shifted to sealed types in order to prevent head crashes caused by dust intrusion. However, in such a sealed magnetic disk device, the temperature inside the sealed device rises due to air friction (windage loss) that occurs as the magnetic disk rotates at high speed. Although cooling is performed using a circulating air cooling method, the temperature of the device still inevitably rises to around 60-70°C, and this temperature rise causes the lubricant film on the magnetic disk surface to evaporate. There is a disadvantage that the lubricating properties of the lubricant disappear and deteriorate, and there is a strong demand for the selection of a lubricating film with excellent heat resistance that can eliminate such disadvantages.

Incidentally, in response to these demands, common lubricants conventionally used to form a lubricant film on the surface of magnetic disks include paraffin, higher fatty acid alcohols, higher fatty acids, higher fatty acid esters, etc. Hydrocarbon-based lubricants or fluorocarbon-based oils, which are their fluorides, lubricants made of silicon-based oils consisting of Si-Si bonding groups, and molybdenum disulfide, tungsten disulfide, graphite,
Solid lubricants made of fluorinated graphite and the like are used alone or in combination. However, 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. The drawback is that it gradually evaporates and loses its lubricity, resulting in poor heat resistance. 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 micron order. Therefore, it is difficult to make the film thin, and it also causes head stick,
Alternatively, phenomena such as the lubricant being deposited on the head surface are likely to occur, and both have the drawback of having only advantages and disadvantages in film characteristics.

Therefore, not only is it extremely difficult to obtain an ultra-thin lubricant film with excellent lubrication durability and heat resistance for high recording density, but magnetic disks coated with such a lubricant film are not suitable for sealed magnetic discs. In disk devices, it has been difficult to perform stable high-density recording or reproduction without head crash failure.

(d) Purpose of the Invention In view of the above-mentioned conventional drawbacks, the present invention provides a method for suppressing evaporation and loss of a lubricant film on the surface of a magnetic disk being rotated in a sealed magnetic disk device by exposing it to an atmosphere of lubricant vapor. The object of the present invention is to provide a novel method for stabilizing a lubricant on the surface of a magnetic disk by which the thickness and lubricating properties of the lubricant film can always be maintained in a good steady state.

(e) Structure of the Invention According to the present invention, a magnetic disk whose surface is coated with a lubricating film is attached to a rotational drive mechanism, and the magnetic disk is sealed in an airtight container. , when the magnetic disk is driven to rotate, in the airtight container,
This is achieved by providing a method for stabilizing a lubricant film on the surface of a magnetic disk, characterized in that the magnetic disk is filled with lubricant vapor and driven to rotate in the lubricant vapor atmosphere.

(f) Embodiments of the invention Examples of the invention will be described in detail below with reference to the drawings.

This figure is a schematic cross-sectional view of a main part of a magnetic disk device, illustrating an example of a method for stabilizing a lubricant film on a magnetic disk surface according to an example. In the figure, 1 is a magnetic disk whose surface facing the magnetic head is coated with a lubricant film (not shown) with a thickness of about 100 Å using a lubricant made of, for example, stearic acid, which is a type of higher fatty acid; A hub mechanism in which a plurality of magnetic disks 1 are integrally supported and is attached to a disk rotation drive mechanism 5; 3 is a center ventilation hole bored in the center of the hub mechanism 2; 4 is in communication with the center ventilation hole 3; Ventilation holes for discharging the circulating atmosphere between each magnetic disk 1; 6, a head positioning mechanism; 7, an airtight storage container; 8, a central ventilation hole 3 drilled in the center of the hub mechanism 2; This is a circulating atmosphere hole provided in the base portion 9. A lubricant vapor generation source 10 containing a lubricant made of stearic acid in the communication hole 8 configured as described above.
A filter 11 is placed on the right side of the lubricant vapor generation source 10 as shown in the figure.

If the disk rotation drive mechanism 5 is driven to rotate the magnetic disk 1 at high speed with the lubricant vapor generation source 10 disposed in the magnetic disk device in this way, air generated by the high speed rotation of the magnetic disk 1 will be generated. The hot air flow whose temperature has increased due to friction flows from the space inside the airtight container 7 into the circulating atmosphere distribution hole 8 provided in the base part 9, as shown by the arrow in the figure, and this hot air flow causes Then, the lubricant vapor generation source 10 is heated to generate lubricant vapor. The generated lubricant vapor passes through the filter 11 together with the hot air flow, and becomes clean lubricant vapor from which dust such as lubricant, large particles of lubricant vapor, etc. are removed. The air flows out between the magnetic disks 1 through the small ventilation holes 4 communicating with the center ventilation hole 3, circulates around the magnetic disk 1, and fills the airtight storage container 7.

Therefore, the vapor pressure of the circulating lubricant vapor surrounding the lubricant film on the surface of each rotating magnetic disk 1 and the vapor pressure when the lubricant film evaporates due to temperature rise due to air friction during high-speed rotation are as follows: A substantially equilibrium state is reached, and 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. The friction coefficient of the lubricant film on the surface of the magnetic disk when it rotates at high speed in a lubricant vapor atmosphere is 0.20 to 0.24, compared to conventional values of 0.45 or more, showing good lubricity.

In the above embodiments, the same lubricant vapor as the lubricant that formed the lubricant film was used to stabilize the lubricant film on the surface of the magnetic disk, but the present invention is not limited to this example. However, the same effect can be obtained even when a lubricant vapor different from the lubricant used to form the lubricant film is used. Further, according to the stabilization method of the present invention, lubricant vapor is naturally deposited not only on the surface of the magnetic disk 1 in the airtight container 7 but also on other functional parts. The membrane is so thin that it does not impair the functionality of the device. Furthermore, the method of installing the lubricant vapor generation source is not limited to the circulating atmosphere distribution hole 8 provided in the base portion 9. For example, the lubricant vapor generation source is installed on the inner wall surface of the airtight container 7 of the device. Alternatively, a coating agent may be applied. Alternatively, lubricant vapor may be generated by heating with a heater or the like, if necessary.

(g) Effect of the invention As is clear from the above explanation, the method for stabilizing a lubricant film on the surface of a magnetic disk according to the present invention stabilizes the lubricant film on the surface of a magnetic disk installed in an apparatus and being rotated. It has the excellent advantage that evaporation loss is suppressed and the thickness and lubricating properties of the lubricating film can always be maintained in a good steady state. As a result, the reliability of the thinner lubricant film has been improved, and it has been shown to have a remarkable effect on higher recording densities. It's advantageous.

[Brief explanation of drawings]

The drawing is a schematic sectional view of a main part of a magnetic disk device for explaining an embodiment of a method for stabilizing a lubricant film on a magnetic disk surface according to the present invention. In the drawings, 1 is 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 disk rotation drive mechanism, 6 is a head positioning mechanism, 7 is an airtight container, Reference numeral 8 indicates a circulating atmosphere circulation hole, 9 indicates a base portion, 10 indicates a lubricant vapor generation source, and 11 indicates a filter.

Claims (1)

[Claims] 1. A device configuration in which a magnetic disk whose surface is coated with a lubricating film is attached to a rotational drive mechanism, and the magnetic disk is sealed in an airtight container,
When the magnetic disk is rotationally driven, the airtight storage container is filled with lubricant vapor and the magnetic disk is rotationally driven in the lubricant vapor atmosphere. A lubricant film on the surface of a magnetic disk, characterized in that the evaporation of the lubricant film on the surface and the adsorption of lubricant vapor onto the surface of the magnetic disk are brought into an equilibrium state, thereby suppressing the loss of the lubricant film through evaporation. Stabilization method.