JP2002005174A - Part of fluid dynamic pressure bearing, manufacturing method of the part, and motor and disc device using the part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a fluid dynamic pressure bearing component from degradation in the quality while the surface hardness of the bearing component is improved. SOLUTION: The fluid dynamic pressure bearing component is configured as having a heat treated layer on the surface of stainless steel and further thereon having a water repellent layer at least partially. Therein the surface hardness Hv of the heat treated layer should preferably be over 600. To maintain and enhance the performance of the component as fluid dynamic pressure bearing, it is preferable that the hardness Hv at the depth 30 μm from the surface is over 800. The water repellent should preferably be of fluorine type as it exerts excellent anti-rusting effect, the most preferably of one having carboxyl radical at the end.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid dynamic bearing component, a method of manufacturing the same, and a motor and a disk drive using the same, and more particularly, to a fluid dynamic bearing component having both excellent surface hardness and corrosion resistance. And a manufacturing method thereof, and a motor and a disk device using the same.

[0002]

2. Description of the Related Art Magnetic disk drives such as HDDs and high-capacity FDDs have remarkably increased in capacity and miniaturization year by year, and the spindle motors used therein have a lifespan that can withstand high speeds, quietness, and excellent vibration. Accuracy is required. From these points, fluid dynamic pressure bearings (hereinafter sometimes referred to as “FDB”) having better performance than conventionally used ball bearings have attracted attention in recent years. The structure of the FDB mainly includes a rotating shaft (shaft) having a thrust plate and a sleeve supporting the rotating shaft. As the characteristics of the shaft used here, it is important to secure seizure resistance and wear resistance with the opposing sleeve, and it is also important to ensure mechanical strength and hardness to support the rotating part It is.

[0003] As a material used for the FDB, stainless steel, particularly free-cutting stainless steel, is preferable in terms of mechanical strength and workability. However, if stainless steel is used for both the shaft and the sleeve, seizure resistance is weakened, and fusion is caused by instantaneous metal contact, and locking is likely to occur.

For this reason, it has been conventionally proposed to use different materials for the shaft and the sleeve, coat the surfaces with different materials, or perform heat treatment to change the physical properties of the materials. In many cases, heat-treated stainless steel was used because mechanical strength and hardness were also required. As heat treatment of stainless steel, general vacuum quenching, carburizing quenching,
There are carbonitriding and nitriding treatments, and better seizure resistance and abrasion resistance can be obtained as compared with stainless steel which is not heat-treated by any heat treatment. Among the above heat treatments, nitriding treatment
It is most suitable in that particularly good seizure resistance is obtained and austenitic stainless steel which cannot be quenched can be treated.

[0005] However, when the above-mentioned heat treatment is performed on stainless steel, there is a problem that the corrosion resistance is reduced because the Cr element on the surface is combined with carbon and nitrogen elements. Particularly, in the nitriding treatment, a compound layer (white layer) of iron nitride having a thickness of about several μm to 15 μm is formed on the outermost surface in addition to a diffusion layer formed by diffusing nitrogen atoms into stainless steel. Since this compound layer cannot form a stable oxide film, the compound layer itself has poor corrosion resistance, and its surface is rough and contaminants are easily involved, so that rust may be generated even under ordinary conditions.
Therefore, the compound layer is generally removed by polishing the surface, and a relatively stable diffusion layer is used.

However, in the shaft of the FDB, a tapped hole, a blind hole, and a groove for retaining oil are formed, and it is difficult to completely remove the compound layer. Tapped holes and blind holes are sealed with screws, so they used to be used even if rust occurred.However, with the speeding up of the spindle motor, the generated rust turned into hard particles and damaged the disk. Or head crash. In particular, in the case of FDB, if rust occurs in these holes and grooves for retaining oil, they may become particles and enter the minute gap between the shaft and sleeve, causing locking and causing serious problems. is there.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of such a conventional problem.
An object of the present invention is to improve mechanical strength, hardness, and seizure resistance while using stainless steel excellent in workability as a base material of a B component, and to prevent deterioration in quality due to corrosion and occurrence of the above-mentioned problems due to particles. It is another object of the present invention to provide a method for manufacturing such an FDB component. Still another object of the present invention is to provide such an FD
An object of the present invention is to provide a motor using a B component and a disk device using the motor.

[0008]

According to the present invention, there is provided a fluid dynamic bearing component characterized in that it has a heat treatment layer on the surface of stainless steel and further has a water repellent layer on at least a part of the heat treatment layer. Is provided.

At this time, the surface hardness Hv of the heat-treated layer is 600
It is desirable that this is the case. In order to maintain and improve the performance as an FDB, it is desirable that the hardness Hv at a depth of 30 μm from the surface is 800 or more. In addition, the water repellent is preferably a fluorine-based water repellent because an excellent rustproofing effect can be obtained, and among them, those having a carboxyl group at the terminal are preferable.

According to the present invention, there is further provided a method of manufacturing a hydrodynamic bearing component, comprising a step of heat-treating a surface of stainless steel processed into a predetermined shape, a step of applying a water repellent, and a step of polishing the surface. A method is provided.

Further according to the present invention, a sleeve member,
A motor provided with a fluid dynamic bearing having a shaft member rotatable relative to the sleeve member and a lubricating fluid filled between the sleeve member and the shaft member,
A motor is provided, wherein at least one of the sleeve member and the shaft member is the fluid dynamic bearing component according to any one of claims 1 to 5.

Further, according to the present invention, in a disk drive on which a disk-shaped recording medium capable of recording information is mounted, a housing, a spindle motor fixed inside the housing, and an information storage medium at a required position of the recording medium. A disk device provided with information access means for writing and / or reading data, wherein the motor is used as the spindle motor.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION As a result of extensive studies to achieve the above object, the present inventors have used stainless steel as a base material, formed a heat-treated layer on the surface thereof, and further formed a water-repellent layer thereon. It has been found that by forming the agent layer, good corrosion resistance in addition to wear resistance can be obtained, and suitability as a bearing component can be improved.

That is, the surface hardness is increased by forming a heat treatment layer on the surface of stainless steel, while the corrosion resistance due to the formation of the heat treatment layer is prevented by forming a water repellent layer.

The stainless steel used in the present invention includes:
There is no particular limitation as long as the surface hardness is improved by heat treatment such as vacuum quenching and nitriding, but all can be used.
Usually, martensitic stainless steels such as SUS410 and SUS420J2 can be used. The nitriding treatment is not limited to martensitic stainless steel, and a wide range of austenitic stainless steels such as SUS304 and ferrites such as SUS430 can be used. Of course, stainless steel that can be used in the present invention is not limited to these.

Further, since extremely high precision and fine processing are required for FDB parts, free-cutting stainless steels can be suitably used as these stainless steels.
Examples include austenitic stainless steels such as SUS304Se and SUS304Pb, martensitic stainless steels such as SUS416, SUS420F and SUS420Pb, and ferritic stainless steels such as SUS430F.

Next, the heat treatment used in the present invention includes:
General vacuum quenching, carburizing, carbonitriding,
Sulfur-nitriding and ordinary nitriding can be mentioned, and any heat treatment may be used as long as the surface hardness Hv after the treatment is 600 or more, preferably 800 or more.

Among the above-mentioned heat treatments, nitriding is particularly desirable because it has a wide range of options for stainless steel, a very high surface hardness of Hv 1,000 or more, and excellent seizure resistance. Here, as the nitriding treatment, conventionally known treatment methods such as liquid nitriding represented by salt bath nitriding, gas nitriding, and ion nitriding can be used.

However, the nitriding treatment generally provides a high surface hardness of Hv 1,000 or more as compared with ordinary vacuum quenching and carburizing quenching, but does not diffuse into the interior because the stirring speed of nitridation is generally slow, so The hardness change increases in the vertical direction, and the inside does not harden. In addition, when nitriding, the material usually expands and the dimensions increase, and the surface becomes rough and uneven due to the formation of the compound layer, so the top surface layer must be polished and removed before use. No. In the finishing stage of the manufacturing process, polishing may be performed at a maximum of about 20 μm. Therefore, the hardness of the stainless steel after nitriding treatment is Hv800 at a depth of 30 μm from the surface.
It is preferable that it is above.

When the stainless steel is heat-treated, the outermost surface layer C
Although r is remarkably carbide and nitride, the corrosion resistance is reduced. However, the polishing can significantly improve the corrosion resistance. In particular, Fe formed on the outermost surface by nitriding
Since the nitride-based compound layer has low corrosion resistance, a water-repellent agent layer is formed in a portion where the Fe nitride layer cannot be removed by polishing. This water repellent layer may be formed by applying and drying a known water repellent on a stainless member.

Examples of the water repellent used in the present invention include long-chain alkyls such as long-chain alkyl salts and long-chain alkyl sulfonates, and fluorine-based water repellents. In particular, fluorine-based water repellents can be suitably used because they have excellent water repellency and film strength. From the viewpoint of easiness and the like, a fluorine-based water repellent is preferably used.

Examples of the fluorine-based water repellent include perfluoroalkylcarboxylic acids and salts thereof, perfluoroalkylthiols, perfluoroalkyltrimethylammonium and salts thereof, and perfluoroalkylsulfonic acids and salts thereof. More than one species can be used in combination. The number of carbon atoms in the perfluoroalkyl group is not particularly limited, but is preferably 10 or more from the viewpoint of improving water repellency. In particular, a water repellent containing perfluoroalkyl carboxylic acid as a main component has good adhesion to stainless steel and excellent corrosion resistance.

The perfluoroalkyl carboxylate has a perfluoroalkyl group and a carboxyl group, and the hydrogen atom of the carboxyl group is substituted with an alkali metal, an ammonium group, an amino group, or the like.

The perfluoroalkyl thiol salt has a perfluoroalkyl group and a thiol group, and the hydrogen atom of the thiol group is substituted with an alkali metal, an ammonium group, an amino group, or the like.

The perfluoroalkyltrimethylammonium salt has a perfluoroalkyl group and a trimethylammonium group, and a halogen is added to the ammonium group.

The perfluoroalkylsulfonic acid salt has a perfluoroalkyl group and a sulfonic acid group, and the hydrogen atom of the sulfonic acid group is substituted with an alkali metal, an alkaline earth metal, an ammonium group, an amine or the like.

The method of applying the water repellent is not particularly limited, and a conventionally known application method such as an immersion (dip coating) method, a spray method, a roll coater method, and a curtain flow coater method can be used. In order to uniformly and uniformly apply the water repellent to the recesses and pores formed, the reduced pressure immersion method is particularly desirable among the above methods. Specifically, for example, a water repellent is dissolved in a solvent, and 0.05 wt.
% Of the water repellent is prepared, and the FDB component is immersed in a container containing the diluted solution. Then, the container is covered with a lid and hermetically closed, and the air inside is evacuated to reduce the pressure. This
Bubbles remaining in the recesses of the FDB part are eliminated, and the entire surface of the FDB part is immersed in the diluting solution. After a predetermined time, the inside of the container is returned to normal pressure, and the FDB component is taken out and dried to form a water repellent agent layer.

The thickness of the water-repellent agent layer may be appropriately determined depending on the composition of the stainless steel used, the degree of heat treatment, and the like.
Generally, a layer thickness of 1 μm or less is sufficient. The preferred lower limit of the layer thickness is several tens of nm. The layer thickness in the immersion method can be controlled by adjusting the concentration of the dilute solution.

Further, the FDB part of the present invention may have a part whose surface is polished. That is, since a nitride layer is formed on the stainless steel surface by the nitriding treatment, the corrosion resistance of the stainless steel decreases. For this reason, the stainless steel surface is polished so that non-nitrided Cr elements are present on the steel surface, and a dense passive layer (hydroxide and oxide of Cr) is formed on the steel surface to improve corrosion resistance. Let it do. The surface can be mainly polished from a technical point of view. The surface polishing of the FDB component may be performed at any time after the nitriding treatment. However, when the water repellent layer is formed on the entire surface of the FDB component, the surface polishing is preferably performed after the formation of the water repellent layer. Since the corrosion resistance of the flat part that can be polished is improved by surface polishing,
In the first place, there is no need to form a water repellent layer thereon, and conversely, if the water repellent layer is present, a problem may occur that the lubricating fluid filled in the minute gap between the shaft member and the sleeve member does not function smoothly. Because there is.

It should be noted that high surface hardness and excellent corrosion resistance can also be obtained by providing a water repellent layer after hardening the stainless steel by quenching. The method of forming the water repellent layer is the same as described above.

A method of manufacturing an FDB part according to claim 6 will be described. First, a stainless steel as a base material is formed into an FDB part such as a shaft or a sleeve. Next, necessary screw holes and dynamic pressure grooves are formed. Examples of the method of forming the dynamic pressure groove include cutting and electrolytic processing. However, according to the electrolytic processing of forming a dynamic pressure groove by electrolytically eluting a metal material, fine burrs, scrapes, or chips are generated. No, this method is recommended. Next, after a heat treatment is performed to form a hard heat treatment layer on the steel surface, a water repellent is applied thereon, and the surface is polished. Of course, a water repellent may be applied after the surface is polished. Since the parts expand and the surface becomes rough due to the heat treatment, the surface is polished in order to accurately maintain the micron gap between the shaft and the sleeve. Since the surface layer of the sliding portion is removed by this surface polishing, the corrosion resistance is significantly improved. On the other hand, tapped holes, blind holes, ventilation holes, oil retaining grooves, etc. cannot be polished. Therefore, a water-repellent agent is applied to these portions where the surface cannot be polished to improve the corrosion resistance. The respective processes of heat treatment, application of a water repellent, and surface polishing are as described above. Then, if necessary, an oil repellent is applied as a sealant to the end of the portion for holding the lubricating fluid.

Next, the motor of claim 7 will be described.
The motor according to claim 7 is a motor provided with a fluid dynamic pressure bearing, wherein at least one of a sleeve member and a shaft member, which are parts of the fluid dynamic pressure bearing, are as described above.
It is a significant feature that any one of the above. With such a configuration, in the motor of the present invention, stable high-speed rotation can be maintained for a long time without generating rust fine powder. Both the sleeve member and the shaft member are the FDB
It is desirable to use a component, but it is also possible to use the FDB component on one side and a component made of a copper-based material or a nickel-plated component on a copper-based material on the other.

Hereinafter, the motor of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic sectional view of a fluid bearing motor for driving a recording disk, which is an embodiment of the motor of the present invention. The motor 1 includes a bracket 2, a shaft 4 whose one end is externally fixed to a central opening of the bracket 2, and a rotor 6 rotatably held relative to the shaft 4. A stator 12 is fixed to the bracket 2, and a rotor magnet 10 is provided on the rotor 6 at a position facing the stator 12.
A rotational driving force is generated between the motor and the rotor magnet 10.

A disk-shaped upper thrust plate 4a and a lower thrust plate 4b projecting outward in the radial direction are provided at the upper and lower portions of the shaft 4, and a gas intervening portion 22 is provided on the outer surface of the shaft between these thrust plates. Is formed.

On the other hand, the rotor 6 is supported on the shaft 4 via a rotor hub 6a on which the recording disk D is mounted on the outer peripheral portion and an inner peripheral side of the rotor 6 via a minute gap in which the lubricating oil 8 is held. And a sleeve 6b. Further, the sleeve 6b is provided with an upper counter plate 7a and a lower counter plate 7b so as to cover the outer sides of the upper and lower thrust plates.

Here, the shaft 4 and the upper and lower thrust plates 4a and 4b correspond to the shaft member of the present invention, and the sleeve 6b corresponds to the sleeve member of the present invention. Both or either one of the shaft member and the sleeve member is obtained by forming a plating layer mainly composed of nickel on the surface of a base material mainly composed of copper. As described later, a herringbone-shaped dynamic pressure groove 24 is formed on the upper and lower inner surfaces of the inner peripheral portion through hole 6c of the sleeve 6b, and a spiral dynamic pressure groove is formed on the lower surface of the upper thrust plate 4a and the upper surface of the lower thrust plate 4b. The pressure grooves 14 are respectively formed by electrolytic processing.

An opposing sleeve 6b extends from the outer peripheral portion of the shaft 4 adjacent to the upper portion of the gas intervening portion 22 provided at the central portion of the shaft 4 to the lower surface, the outer peripheral surface, and the outer peripheral portion of the upper thrust plate. Inner peripheral through hole 6c
A small gap is formed between the upper part of the upper counter plate 7a and the lower part of the upper counter plate 7a, and the lubricating oil 8 is held. On the lower surface of the upper thrust plate 4a and on the upper surface of the lower thrust plate 4b, a spiral dynamic pressure groove 14 for generating a dynamic pressure in the lubricating oil 8 with the rotation of the rotor 6 is formed. The dynamic pressure groove 14 has a function of generating a supporting force for holding the rotor portion in the axial direction when the motor rotates, and at the same time, has an effect of pushing the lubricating oil 8 back in the direction of arrow A. Further, a herringbone-shaped dynamic pressure groove 24 is formed in the lubricating oil holding portion on the upper and lower inner surfaces of the inner peripheral portion through hole 6c of the sleeve 6b. The dynamic pressure groove 24 has a function of generating a supporting force for holding the rotor portion in the radial direction when the motor rotates, and at the same time, has an effect of pushing up the lubricating oil 8 in the direction of arrow B.

The distribution of the dynamic pressure of the lubricating oil 8 in the minute gap generated by these dynamic pressure grooves is highest at the inner peripheral portion P of the lower surface of the upper thrust plate. As a result, when the air dissolved in the lubricating oil 8 becomes bubbles, the bubbles are diffused and eliminated to the outside of the inner peripheral portion P, and the lower gas intervening portion 22 or the upper counter plate 7a lower surface gap is removed. Leads to. These gaps are directly or externally open air communication holes 2.
Since the air is released to the atmosphere by 0, the air bubbles are released to the outside air from here, and lubricating oil leakage due to expansion of the air bubbles is prevented.

Further, a taper seal portion is formed between the lower surface of the counter plate 7a, which is the end of the lubricating oil holding portion, and the upper surface of the upper thrust plate 4a. An oil repellent is applied to the end of the seal. Similarly, the gas intervening portion 22 at the center of the shaft 4, which is the other end of the lubricating oil holding portion,
A taper seal portion is formed between the outer peripheral surface of the shaft 4 and the inner peripheral surface of the sleeve 6b so that the gap gradually increases as the distance from the lubricating oil holding portion to the lower side in the axial direction increases. An oil repellent is applied to the end. By the taper seal portions formed at both ends, the lubricating oil is held at a position where the dynamic pressure, the atmospheric pressure, and the surface tension of the taper seal portion generated inside the lubricating oil are balanced. The oil repellent applied to the tapered seal portion also has a function of preventing so-called oil migration, in which lubricating oil diffuses along the metal surface of the shaft or sleeve. With these lubricating oil holding structures, a fluid bearing structure with no leakage of lubricating oil and high load supporting force is realized.

A similar structure of the minute gap, the dynamic pressure groove, and the lubricating oil holding portion is provided in the gas intervening portion 2 provided in the center of the shaft 4.
2, the lower thrust plate 4b and the lower counter plate 7b are formed upside down so that the rotor portion is more stably supported by the lower dynamic pressure bearing portion.

The hydrodynamic bearing motor having such a structure is
The upper and lower counter plates 7a and 7b effectively prevent the lubricating oil 8 from escaping outward due to the rotational centrifugal force even at a high speed of about 20,000 revolutions per minute, thereby realizing even higher speed and stable rotation. can do.

Next, a disk device according to claim 8 will be described. This disk device writes and / or writes information on a recording medium mounted on a rotating section of a spindle motor.
Alternatively, an apparatus for performing reading by the information access means, wherein the motor according to claim 7 is used as the spindle motor.

FIG. 2 is a schematic explanatory view showing one embodiment of the disk drive of the present invention. Inside a housing 71, a spindle motor 72 rotatably supporting a disk plate (recording medium) 73 for storing various information in a digital format at high density, and information access means for reading and writing information from and to the disk plate 73 77 are arranged. The information access means 77 includes a head 76 for reading and writing information on the disk plate 73, and an arm 75 for supporting the head 76.
And an actuator unit 74 for moving the head 76 and the arm 75 to required positions on the disk plate 73. The motor of claim 8 is used as the spindle motor 72.

The information density that can be stored on a disk plate has been dramatically improved in recent years, and dust and
A clean environment with extremely little dust is essential. Therefore, in order to make the inside of the housing 71 a highly clean space insulated from the outside air, the information access means 77 and the spindle motor 72, which are the internal components thereof, use the mist of the lubricating oil used therein. It is desirable to use a mechanism that does not leak to the outside.

[0045]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples, but the present invention is not limited thereto.

(Preparation of Test Samples) Stainless steel (SUS304Se) was processed into a cylindrical shape, and four samples having tapped holes formed on the upper surface thereof were prepared (samples A, B, C, and D). Samples A and B were subjected to a salt bath nitriding treatment in an ammonia gas at a treatment temperature of 530 ° C. for a treatment time of 20 hours to form a nitride layer on the stainless steel surface. The surface hardness Hv of the samples A and B after the nitriding treatment was 1,000. On the other hand, the surface hardness Hv of the samples C and D not subjected to the nitriding treatment was 200. Next, for samples A and C, a perfluoroalkylcarboxylate as an oil repellent was applied on the surface by a dipping method to form a water repellent layer.

(Evaluation of surface hardness and corrosion resistance)
The surface hardness of B, C and D was measured, and the samples were subjected to 168 at a temperature of 80 ° C. and a humidity of 90%.
The sample was left for a while, and the presence or absence of rust on the sample surface was visually determined. Table 1 shows the results.

[0048]

[Table 1]

According to Table 1, Sample A in which a nitride layer was formed on the steel surface by nitriding treatment and a water-repellent agent layer was further formed thereon had a high surface hardness Hv of 1,000 and showed a high rust resistance. No outbreaks were seen. On the other hand, in Sample B in which the nitride layer was formed but the water repellent layer was not formed, although the surface hardness Hv was as high as 1,000, rust was generated in the corrosion resistance test. Samples C and D in which no nitride layer was formed were:
Although the surface hardness Hv was as low as 200, rust did not occur in either sample regardless of the presence or absence of the water repellent layer.

[0050]

According to the fluid dynamic pressure bearing component of the present invention, the heat treatment layer is formed on the surface of stainless steel, and the water repellent layer is further provided on at least a part of the surface. It is possible to prevent deterioration in quality due to corrosion while improving hardness. The surface hardness Hv after the heat treatment is 60
When it is 0 or more, the wear resistance is improved. When the heat-treated layer is a nitrided layer and the hardness Hv at a depth of 30 μm from the surface is 600 or more, the performance as an FDB can be further maintained and improved. Further, when a fluorine-based water repellent is used as the water repellent, a more excellent rust preventive effect can be obtained, and when a compound having a terminal carboxyl group is used, very excellent rust preventive hardening can be obtained. In the manufacturing method according to the sixth aspect, since a step of heat-treating the surface of the stainless steel, a step of applying a water repellent, and a step of polishing the surface are provided, the fluid dynamic pressure bearing member having high surface hardness and excellent corrosion resistance can be efficiently manufactured. It can be manufactured in a special way. In the motor according to the seventh aspect, since the fluid dynamic pressure bearing component according to any one of the first to fifth aspects is used, stable rotation at high speed over a long period of time can be realized. In the disk device according to the eighth aspect, since the motor is used as the spindle motor, the life of the device can be extended.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a motor of the present invention.

FIG. 2 is a schematic configuration diagram of a disk device of the present invention.

[Explanation of symbols]

 Reference Signs List 1 motor 4 shaft 6b sleeve (sleeve member) 8 lubricating oil (lubricating fluid) 14, 24 dynamic pressure groove 16 workpiece 44 tool electrode 44a exposed electrode 71 housing 72 spindle motor 73 disk plate (recording medium) 77 information access means

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G11B 33/12 313 G11B 33/12 313B 313C H02K 5/16 H02K 5/16 Z 7/08 7/08 A // F16C 33/12 F16C 33/12 Z (72) Inventor Yasushi Iwasaki 10 Nishikyogoku Tsutomachi, Ukyo-ku, Kyoto-shi, Kyoto F-term in the Central Research Laboratory of Nidec Corporation (reference) 3J011 AA08 AA20 BA02 CA02 DA01 DA02 JA02 5D109 BA14 BA20 BB13 BB17 BB31 5H605 BB05 BB09 BB10 BB14 BB19 CC04 DD09 EB02 EB06 EB28 5H607 AA00 AA12 BB01 BB07 BB09 BB14 BB17 BB25 CC01 DD16 GG12 GG15 KK10

Claims (8)

[Claims] 1. A heat treatment layer on a surface of stainless steel,
A fluid dynamic bearing component, further comprising a water repellent layer on at least a portion thereof. 2. The fluid dynamic bearing component according to claim 1, wherein the heat treatment layer has a surface hardness Hv of 600 or more. 3. The fluid dynamic bearing component according to claim 1, wherein the heat treatment layer is a nitriding layer, and has a hardness Hv of 800 or more at a depth of 30 μm from the surface. 4. The fluid dynamic bearing component according to claim 1, wherein the water repellent is a fluorine-based water repellent. 5. The fluid dynamic bearing component according to claim 4, wherein the fluorine-based water repellent has a carboxyl group at a terminal. 6. A method of manufacturing a fluid dynamic bearing component, comprising a step of heat treating a surface of stainless steel processed into a predetermined shape, a step of applying a water repellent, and a step of polishing the surface. 7. A fluid dynamic bearing comprising a sleeve member, a shaft member rotatable relative to the sleeve member, and a lubricating fluid filled between the sleeve member and the shaft member. A motor comprising: at least one of the sleeve member and the shaft member is the fluid dynamic bearing component according to claim 1. 8. A disk drive on which a disk-shaped recording medium capable of recording information is mounted, a housing, a spindle motor fixed inside the housing, and writing and / or reading of information at a required position of the recording medium. 8. A disk device comprising: an information access unit for the disk drive, wherein the motor according to claim 7 is used as the spindle motor.