JP2000027853A - Dynamic pressure bearing, manufacture of dynamic pressure bearing, motor and rotary body device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dynamic pressure bearing excellent in durability and easy in manufacture. SOLUTION: A dynamic pressure bearing has a cylindrical outer cylinder member having the hollow part, an inside column member 12 fitted to and installed in the hollow part of the outer cylinder member 11 and thrust plates 13, 14 installed on both ends of this inside column member 12 and respectively opposed to the upper end surface or the lower end surface of the outer cylinder member 11, the inside column member 12 has a columnar base material and hydrogenated amorphous diamond layers of the surface of the peripheral surface and a dynamic pressure generating groove is bored up to the depth extending to the inside of the base material from the surface of the hydrogenated amorphous diamond layers. The thrust plates 13, 14 have a disk-shaped base material, the hydrogenated amorphous diamond layers 13b, 14b formed on a plane of the base material and a dynamic pressure generating groove having the depth extending to the inside of the base material from the surface of the hydrogenated amorphous diamond layers 13b, 14b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dynamic pressure bearing, a method for manufacturing a dynamic pressure bearing, a motor, and a rotating body device, and more particularly, to a method for maintaining good durability, easy processing, and low cost. The present invention relates to a dynamic pressure bearing, a dynamic pressure bearing manufacturing method, a motor, and a rotating body device.

[0002]

2. Description of the Related Art Conventionally, dynamic pressure bearings have been used as bearings for spindle motors in various disk devices such as hard disk drives, rotary polygon mirror devices such as printers, and other rotating devices. The dynamic pressure bearing
It has a bearing member fixed to the rotating body side and a bearing member fixed to the non-rotating body side, and a dynamic pressure generating groove is formed on one of the opposing surfaces of these bearing members. . During rotation of the rotating body, a fluid such as air or oil is caught between the two bearing members by the dynamic pressure generating groove to generate a dynamic pressure, and the rotating body supports the rotating body with respect to the non-rotating body.

A dynamic pressure bearing for supporting a rotating body in a radial direction with respect to a non-rotating body includes a hollow or solid inner pillar member coaxially arranged with the rotating shaft of the rotating body as a bearing member;
An outer cylindrical member having a hollow portion into which the inner column member is fitted. The dynamic pressure generating groove is formed on either the inner peripheral surface of the outer cylinder member or the outer peripheral surface of the inner column member. The dynamic pressure bearing that supports the rotating body in the thrust direction with respect to the non-rotating body,
The bearing member includes a hollow or solid outer column member coaxially arranged with the rotating shaft of the rotating body, and a thrust plate facing an end surface of the outer column member. The dynamic pressure generating groove is formed on an end face of the outer column member or a plane of the thrust plate on the outer column member side. Such a dynamic pressure bearing
There is an advantage that friction between members during high-speed rotation is small and good durability can be obtained.

In the conventional dynamic pressure bearing manufacturing method for manufacturing the above dynamic pressure bearing, the dynamic pressure generating groove is formed by etching or directly engraving the base material. In the technique (etching) of etching a dynamic pressure generating groove on a base material, a photoresist film is applied to the surface of a base material made of a metal such as stainless steel or aluminum, and a portion other than the dynamic pressure generating groove is irradiated with laser light or the like. After hardening, the portion corresponding to the dynamic pressure generating groove is melted out with a solvent, or a corrosion-resistant coating is applied to the entire surface of the base material, and then only the portion corresponding to the dynamic pressure generating groove is directly removed by laser light. Then, the base material is immersed in a chemical solution, and only the exposed portion is corroded to form a dynamic pressure generating groove. Thereafter, the corrosion-resistant coating such as a photoresist is removed by a solvent. In the technique of directly engraving the dynamic pressure generating groove, the dynamic pressure generating groove is directly engraved by a laser beam while being rotated while pressing a hard ball against a substrate (rolling method).

[0005]

However, such a dynamic pressure bearing as described above performs the bearing by a sufficient dynamic pressure generated at the time of high-speed rotation. Therefore, at the time of low-speed rotation where the generated dynamic pressure is small, the bearing member is used. The two abut each other,
There is a problem that the member is easily worn and the vicinity of the dynamic pressure generating groove is easily damaged. As a method of solving such a problem of the dynamic pressure bearing, a method of coating and protecting the entire surface of the bearing member with a lubricant such as fluorine or hydrogenated amorphous diamond is considered. However, when coating the bearing member on which the dynamic pressure generating groove is formed, the coating is easily thinned and cracked at the peripheral portion of the dynamic pressure generating groove and easily peeled off.
Since the shape of the dynamic pressure generating groove differs from that formed on the base material due to the coating and the dynamic pressure also changes, there is a drawback that it is necessary to take this into consideration at the time of design.

Further, any of the above-described methods of manufacturing a dynamic pressure bearing has a problem that manufacturing time and equipment costs are excessive. That is, the etching method involves a large number of steps such as forming a corrosion-resistant film using a photoresist or the like, forming a dynamic pressure generation groove pattern, and removing the corrosion-resistant film. Further, when a dynamic pressure generating groove is formed on the peripheral surface of the outer cylinder member, the outer column member, and the inner column member, a corrosion-resistant coating is uniformly formed on the base material, or a dynamic pressure generating groove pattern is formed. Therefore, there is a possibility that good working accuracy of the dynamic pressure generating groove cannot be obtained. Furthermore, when a portion corresponding to the dynamic pressure generating groove is removed from a corrosion-resistant film such as a photoresist by a laser beam, a high-power laser is required, and the laser beam causes irregularities on the surface of the base material.
This unevenness may be amplified by etching, and the processing accuracy of the dynamic pressure generating groove may be deteriorated.

In the method of directly engraving the dynamic pressure generating groove by the rolling method, the base material existing in the portion of the dynamic pressure generating groove is pushed to the periphery, so that the periphery of the dynamic pressure generating groove rises. Then, it is necessary to perform rework for correcting the protrusion by cutting. The method of directly engraving the dynamic pressure generating groove by using a laser beam requires a high-power laser. In addition, since the corrosion-resistant coating is melted by the laser beam, the periphery of the dynamic pressure generating groove is raised, and rework for cutting and correcting the protrusion is required.

Although not yet known as a dynamic pressure bearing, a hydrogenated amorphous diamond film is formed on the surface of a substrate, and only a portion of the film corresponding to the dynamic pressure generating groove is removed by laser beam irradiation. The present applicant has proposed a method in which the surface of the base material is exposed to form a dynamic pressure generating groove. Hydrogenated amorphous diamond coatings can be easily and precisely formed on a substrate with a uniform thickness by a vapor deposition method, and the surface of the substrate can be affected by low-power laser light. Therefore, the dynamic pressure generating groove can be formed with high accuracy. Further, since the hydrogenated amorphous diamond film is evaporated as water vapor or carbon dioxide without being melted by the laser beam, there is an advantage that the periphery of the dynamic pressure generating groove does not protrude and rework is unnecessary. In addition, the hydrogenated amorphous diamond film has a high hardness and functions as a lubricating protective film, so that there is an advantage that the durability of the bearing members against friction is improved. However, a large amount of time is required to form a film having a depth equal to the depth of the dynamic pressure generating groove on the surface of the base material by the vapor phase growth method, and there is a problem that the cost increases.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a dynamic pressure bearing, a method of manufacturing a dynamic pressure bearing, and a motor capable of maintaining good durability, easily processed, and manufactured at low cost. , And a rotator device.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a cylindrical outer cylinder member having a hollow portion, and a cylindrical outer cylinder member fitted in the hollow portion and having a relative position with respect to the outer cylinder member. A rotating or hollow inner column member, and a dynamic pressure generating groove formed on one of opposing surfaces of the outer cylindrical member and the inner column member, wherein the dynamic pressure generating groove is provided. A hydrogenated amorphous diamond layer is formed on the facing surface of the outer cylinder member and the inner column member in which the hydrogenated amorphous diamond layer is formed. A dynamic pressure bearing is provided extending to the inside (first configuration).

In this dynamic pressure bearing, the hydrogenated amorphous diamond layer disposed on the surface facing the outer cylinder member and the inner column member functions as a lubricating film and a protective film, so that the dynamic pressure during low-speed rotation is small. Even in this case, the rotation is smooth, and wear and damage of these members are avoided. Since the hydrogenated amorphous diamond layer has good corrosion resistance, hydrogenated amorphous diamond is used as a corrosion-resistant film when the dynamic pressure generating groove is formed by etching, and this is not removed as it is. Can be used.

In order to solve the above-mentioned problems, the present invention provides a hollow or solid outer column member, and a thrust which faces an end face of the outer column member and rotates relatively to the outer column member. A plate, and a dynamic pressure generating groove formed in one of the opposing surfaces of the outer column member and the thrust plate, wherein the outer column member in which the dynamic pressure generating groove is formed, and A hydrogenated amorphous diamond layer is formed on the surface facing the thrust plate, and the dynamic pressure generating groove is formed by a dynamic pressure drilling extending up to the inside of the substrate on which the hydrogenated amorphous diamond layer is formed. A bearing is provided (second configuration).

[0013] In this dynamic pressure bearing, the hydrogenated amorphous diamond layer disposed on the opposing surface of the outer column member and the thrust plate functions as a lubricating film and a protective film. In this case, the rotation is smooth and wear and damage of these members are avoided. Since the hydrogenated amorphous diamond layer has good corrosion resistance, use hydrogenated amorphous diamond as the corrosion-resistant film when forming the dynamic pressure generating grooves by etching, and remove this as it is. Can be used without.

In the first and second configurations,
The hydrogenated amorphous diamond layer may have a thickness of 2 μm or less. Thus, the time required for forming the hydrogenated amorphous diamond layer by the vapor phase growth method can be reduced. Then, by forming a hydrogenated amorphous diamond layer having a uniform thickness by a vapor phase growth method, the depth of the dynamic pressure generation groove can be easily formed with good accuracy, and the reliability of operation is improved. be able to.

Further, the present invention provides a dynamic pressure bearing manufacturing method for the dynamic pressure bearing according to the first and second configurations, wherein the dynamic pressure generating groove is formed on the surface of the base material. A DLC layer forming step of uniformly forming a hydrogenated amorphous diamond layer, a pattern forming step of removing the hydrogenated amorphous diamond layer according to the dynamic pressure generating groove pattern after the DLC layer forming step, After the step, an etching step of engraving the dynamic pressure generating groove by wet etching the exposed surface of the base material is provided.

According to the above-described method of manufacturing a dynamic pressure bearing, a hydrogenated amorphous diamond layer is formed and used as a corrosion resistant film in etching for forming a dynamic pressure generating groove. Therefore, the hydrogenated amorphous diamond layer is not removed. It can function as it is as a lubricating film and a protective film. Therefore, it is possible to manufacture a dynamic pressure bearing that does not require a removal process, rotates smoothly at low speed rotation, and has little wear and damage to members.

In the method for manufacturing a dynamic pressure bearing,
In the LC layer formation step, the hydrogenated amorphous diamond layer may be formed on the surface of the base material by a vapor phase growth method. By using the vapor phase growth method, the hydrogenated amorphous diamond layer can be accurately formed to have a uniform thickness, and the dynamic pressure generation groove can be formed more precisely.

In the method for manufacturing a dynamic pressure bearing,
In the LC layer forming step, it is preferable to form the hydrogenated amorphous diamond layer such that the layer thickness is 2 μm or less. When the hydrogenated amorphous diamond layer has a thickness of 2 μm or less, a sufficient lubricating effect and a protective effect on the base material can be obtained, and even when the hydrogenated amorphous diamond layer is formed by the vapor phase growth method, only a short time is required. Because.

In the method of manufacturing a dynamic pressure bearing, in the pattern forming step, the hydrogenated amorphous diamond layer may be removed by a laser beam. The hydrogenated amorphous diamond layer can remove a portion corresponding to the dynamic pressure generation groove with low-power laser light without affecting the substrate surface, and can expose the substrate surface smoothly. . Therefore, it is possible to form a dynamic pressure generating groove having a very well-shaped shape by the etching process.

In this case, the method includes a heat-insulating layer forming step of uniformly forming a heat-insulating layer of a heat-insulating material on the surface of the substrate on which the dynamic pressure generating groove is formed.
After the heat-insulating layer forming step, a hydrogenated amorphous diamond layer is formed on the heat-insulating layer by lamination, and in the etching step, after the pattern forming step, the exposed heat-insulating layer is removed and the substrate is formed according to the pattern. After exposing, the dynamic pressure generating grooves may be formed on the exposed surface of the base material by wet etching. By providing the heat insulating layer in this manner, when the hydrogenated amorphous diamond layer is removed by laser light, heat is prevented from being transmitted to the base material and is radiated, and the hydrogenated amorphous diamond layer is efficiently removed. Can be.

Further, the light absorbing layer forming step of laminating a light absorbing layer having a better light absorbing property to the laser beam than the hydrogenated amorphous diamond layer on the hydrogenated amorphous diamond layer formed in the DLC layer forming step is performed. The pattern forming step may include removing the light absorbing layer and the hydrogenated amorphous diamond layer. By providing the light-absorbing layer in this way, when the hydrogenated amorphous diamond layer is removed by laser light, the laser light is more effectively absorbed and the hydrogenated amorphous diamond layer efficiently corresponds to the dynamic pressure generation groove pattern. And can be removed.

Further, in order to solve the above-mentioned problems, the present invention provides a motor provided with the above-described dynamic pressure bearing of the first configuration or the second configuration. Further, the present invention provides a rotating body device provided with the above motor.

[0023]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of the dynamic pressure bearing of the present invention. As shown in FIG. 1, the dynamic pressure bearing 10 of the present embodiment is a so-called H-shaped dynamic pressure bearing in which a radial bearing is sandwiched between a pair of thrust bearings. The dynamic pressure bearing 10 includes a cylindrical outer tube member (outer column member) 11 having a hollow portion, an inner column member 12 fitted in the hollow portion of the outer cylinder member 11, and both ends of the inner column member 12. Attached to the outer cylinder member 1
And two thrust plates (upper thrust plate 13 and lower thrust plate 14) facing one upper end surface or lower end surface.

FIGS. 2A and 2B are views showing the inner column member of the dynamic pressure bearing 10 of the present embodiment, wherein FIG. 2A is a sectional view and FIG. 2B is a side view. As shown in FIG. 2A, the inner column member 12
Has a cylindrical base material 12a made of a metal such as aluminum or stainless steel, and a hydrogenated amorphous diamond layer 12b formed on the peripheral surface of the base material 12a. The inner column member 12 has an outer peripheral surface facing the cylindrical member 11 with a small gap therebetween, and FIG.
As shown in FIG. 5, on the outer peripheral surface (opposing surface) of the inner column member 12,
A dynamic pressure generating groove (two rows of oblique lines) 12c for generating a radial dynamic pressure is formed. The dynamic pressure generating groove 12c is formed by piercing from the surface of the hydrogenated amorphous diamond layer 12b to a depth extending from the surface of the hydrogenated amorphous diamond layer 12b to the inside of the base material 12a. It is deeper than the thickness. And the base material 12a is exposed in the dynamic pressure generation groove 12c.

FIG. 3 is a plan view showing a surface of the lower thrust plate 14 of the dynamic pressure bearing 10 according to the present embodiment which faces the outer cylindrical member 11. The lower thrust plate 14 includes a disk-shaped base made of a metal such as aluminum or stainless steel, and a hydrogenated amorphous diamond layer 14b formed on one plane of the base. At a depth extending from the surface of the hydrogenated amorphous diamond layer 14b to the inside of the base material, as shown in FIG. 3, a dynamic pressure generating groove (herring bone groove) 14c for generating a dynamic pressure in the thrust direction is formed. Is formed. The base material is exposed in the dynamic pressure generating groove 14c. Similarly, the upper thrust plate 13 is also provided with a hydrogenated amorphous diamond layer on one surface of a disk-shaped substrate made of a metal such as aluminum or stainless steel. A herringbone groove opposite to the plate 14 is formed.

Then, as shown in FIG. 1, the upper thrust plate 13 is provided with the hydrogenated amorphous diamond layer 1.
The hydrogenated amorphous diamond layer 13b faces the upper end surface of the outer cylindrical member 11 coaxially fixed to the upper end of the inner column member 12 with 3b facing downward. Further, the lower thrust plate 14 has a hydrogenated amorphous diamond layer 14b.
Is fixed coaxially to the lower end of the inner pillar member 12 with
The hydrogenated amorphous diamond layer 14 b faces the lower end surface of the outer cylinder member 11.

Next, an embodiment of the method for manufacturing a dynamic pressure bearing according to the present invention will be described, and a method for manufacturing the above-described dynamic pressure bearing 10 will be described. In the manufacturing method of the present embodiment, the inner column member 12, the outer cylindrical member 11, and the two thrust plates 1
After molding and processing 3,14, they are assembled.

FIG. 4 is an explanatory view showing a manufacturing process of the inner column member 12 of the dynamic pressure bearing 10 of the present embodiment.
(A), (c) and (e) are cross-sectional views of the inner column member in the course of manufacture, (b) is a plan view in the same state as (a), and (d) is a plane view in the same state as (c). (F) is a plan view of the same state as (e). When manufacturing the inner column member 12,
First, a cylindrical base material 12a made of metal is formed, and the peripheral surface of the base material 12a is surface-activated by alkali degreasing and acid cleaning.

As shown in FIGS. 4A and 4C, a hydrogenated amorphous diamond film is formed on the peripheral surface of the base material 12a by a vapor phase growth method such as a plasma CVD method or a sputtering method. A hydrogenated amorphous diamond layer 12b is formed. The thickness t of the hydrogenated amorphous diamond layer 12b is preferably 0.3 to 2 μm, and more preferably 0.5 to 1 μm. 0.3μ
If it is less than m, it may be damaged at low speed rotation, and sufficient lubrication and protection of the base material 12a may not be obtained. If it exceeds 2 μm, the time required for formation by the vapor phase growth method is too long. On the other hand, the lubricating action and the protecting action by the hydrogenated amorphous diamond layer 12b do not increase and are inefficient.

Next, as shown in FIGS. 4B and 4D, the laser beam L is applied to remove the hydrogenated amorphous diamond layer 12b from the portion corresponding to the dynamic pressure generating groove by the laser beam. . FIG. 5 is a schematic configuration diagram showing a dynamic pressure generating groove pattern forming apparatus used in the dynamic pressure bearing manufacturing method of the present embodiment. The dynamic pressure generating groove pattern forming device 2 includes a laser oscillation device 3 that emits a laser beam L (eg, an argon ion laser, a YAG laser, or a carbon dioxide laser) at a low output of several watts into an airtight system 8. A condenser lens 4 for reducing the diameter of the laser light L from the oscillation device 3; a galvano mirror 5 for deflecting the optical path by reflecting the laser light L passing through the condenser lens while swinging in the direction of arrow A in the figure; A mounting table 6 that rotates in the direction of the middle arrow B is provided.
The airtight system 8 is provided with a vacuum suction device (not shown) for evacuating the inside of the airtight system 8 and an oxygen cylinder 9 for filling the inside of the airtight system 8 with oxygen.

Then, the base material 12a (the inner column member 12) on which the hydrogenated amorphous diamond layer 12b is formed is mounted on the mounting table 6 with one end face down, and the closed system 8 is closed. The inside of the closed system 8 is evacuated (not shown), the oxygen cylinder 9 is opened and filled with oxygen, and the laser beam L is emitted from the laser oscillation device 3 while rotating the mounting table 6.

The focus of the emitted laser light L is adjusted by the condenser lens 4, and the mounting table 6 is moved by the galvanometer mirror 5.
Above, the inner column member 12 rotating around the axis is scanned in the axial direction, and the inner column member 12 is irradiated on a portion corresponding to the dynamic pressure generating groove pattern. The hydrogenated amorphous diamond layer 12b is thermally decomposed into carbon dioxide and water vapor at 800 to 900 ° C. by the thermal energy of the laser beam,
The surface of the base material 12a is exposed corresponding to the pattern of the dynamic pressure generating groove. At this time, under the above-mentioned oxygen atmosphere or other reactive gas such as ozone hydrogen peroxide, even if the processing speed is high, complete combustion is performed without generating carbide powder. Further, since the laser beam has a low output, the substrate is not affected. Therefore, a smooth substrate surface during molding is exposed.

Subsequently, the inner pillar member 12 is immersed in an etching solution for wet etching, and the inner pillar member 12 is immersed in FIGS.
As shown in FIG. 5, the exposed surface of the base material 12a is corroded to form a dynamic pressure generation groove 12c extending to the inside of the base material.
When the substrate 12a is made of aluminum, a mixed solution of phosphoric acid, acetic acid, nitric acid and pure water is used as an etching solution,
The substrate 12a can be etched at 80 ° C. If the substrate 12a is stainless steel, the substrate 12a can be etched at room temperature using an aqueous ferric chloride solution. The dynamic pressure generating groove 12c to be formed depends on the size of the dynamic pressure bearing 10, the distance between members, the application, etc., but when used in a polygon mirror motor or the like of a printer, hydrogen is generated from the hydrogenated amorphous diamond layer 12b surface. Including the thickness t of the amorphous diamond layer 12b,
7, 8 μm is preferred.

Then, the thrust plates 13 and 14 are also formed with the dynamic pressure generating grooves by the same process as described above, and the outer cylinder member 11 is fitted to the inner column member 12. In addition, inner pillar member 1
The thrust plates 13 and 14 are fixed to the two end surfaces with the hydrogenated amorphous diamond layers 13b and 14b sides inside (the outer cylinder member 11 side), and the production of the dynamic pressure bearing 10 of this embodiment is completed.

In the dynamic pressure bearing 10 manufactured by the above-described manufacturing method, the outer cylindrical member 11 is fixed to one of the rotating part and the fixed part of the rotating body, and the inner column member 13 and the thrust plate 13 are fixed to the other. , 14 are fixed. Then, when the rotating part of the rotating body rotates and the outer cylinder member 11 relatively rotates with respect to the inner column member 12 and the thrust plates 13 and 14, the upper thrust plate 1
The dynamic pressure air is pushed into the gap between the end face of the outer cylinder member 11 and the thrust plates 13 and 14 by the pumping action of the dynamic pressure generating groove 3 and the dynamic pressure generating groove 14c of the lower thrust plate 14, and the dynamic pressure in the thrust direction is reduced. appear. In addition, inner pillar member 1
The dynamic pressure air is pushed into the space between the peripheral surface of the outer cylinder member 11 and the inner column member 12 by the pumping action of the second dynamic pressure generating groove 12c, and a radial air dynamic pressure is generated.

At the time of low-speed rotation, the generated dynamic pressure is small, so that the outer cylindrical member 11 relatively rotates while being in contact with the lower thrust plate 14 and the columnar member 12. At this time, hydrogenated amorphous diamond layers 12b and 14b are formed on the opposing surfaces of the columnar member 12 and the outer cylindrical member 11 of the thrust plate 14, and the hydrogenated amorphous diamond layers 12b and 14b serve as a lubricating film and a protective film. Therefore, the friction generated between the outer cylinder member 11, the inner column member 12, and the lower thrust plate 14 is small, and wear and damage hardly occur. At the time of high-speed rotation, the dynamic pressure increases, the outer cylinder member 11 floats between the two thrust plates 13 and 14, and the inner cylinder member 12 and the thrust plate 13 ,
Rotate relative to 14.

According to the dynamic pressure bearing 10 of the present embodiment, the dynamic pressure generating groove forming surface of each member (the peripheral surface of the columnar member 12 and the surface of the upper thrust plate 13 and the lower thrust plate 14 on the outer cylinder member 11 side) Has a Vickers hardness of 1200
Hydrogenated amorphous diamond layer 1 of ~ 2000
2b, 13b, 14b are formed, and the hydrogenated amorphous diamond layers 12b, 13b, 1 during rotation are formed.
Since 4b functions as a protective film and a lubricating film, smooth rotation can be obtained even at low speed rotation, wear and breakage of members can be avoided, and a highly durable dynamic pressure bearing can be obtained. According to the dynamic pressure bearing 10 of the present embodiment, since the lubricating / protective film on the dynamic pressure generating groove forming surface of each member is the hydrogenated amorphous diamond layers 12b, 13b, and 14b, corrosion resistance occurs during the etching process for forming the dynamic pressure generating grooves. The hydrogenated amorphous diamond layer formed on the surface of the substrate as the conductive film can be used without removing it. Therefore, it is possible to manufacture the device at a low cost with a small number of steps.

According to the dynamic pressure bearing 10 of the present embodiment, the dynamic pressure generating grooves are formed in the hydrogenated amorphous diamond layer 12b,
13b and 14b and the depth extending to the inside of the substrate, the hydrogenated amorphous diamond layers 12b and 13b
The thickness of the hydrogenated amorphous diamond layers 12b, 13b, and 14b can be suppressed to a level (2 μm or less) in which the hydrogenated amorphous diamond layers 12b, 13b, and 14b can function as a lubricating / protective film. Can be suppressed. Since the hydrogenated amorphous diamond layer can be suppressed to 2 μm or less, it can be formed in a short time when it is formed by the vapor phase growth method. In the vapor phase growth method, the hydrogenated amorphous diamond layer grows in proportion to time up to a layer thickness of 2 to 3 μm, and the growth becomes slower when the layer thickness is more than this. For example, it takes about 2.5 hours to make the layer thickness 2-3 μm, but it takes about 8 hours to make the layer thickness 5 μm. In this embodiment, the hydrogenated amorphous diamond layer is formed more efficiently and in a shorter time by setting the layer thickness before the growth speed becomes gentle.

According to the dynamic pressure bearing 10 of the present embodiment, the hydrogenated amorphous diamond layers 12b, 13b, and 14b are used as the lubrication and protection films on the dynamic pressure generating groove forming surface of each member. It can be formed on the surface of a substrate. Then, by using the vapor phase growth method, the hydrogenated amorphous diamond layer can be accurately formed with a uniform thickness, thereby improving the processing accuracy of the member and increasing the reliability of the operation of the dynamic pressure bearing 10. be able to.

According to the method of manufacturing a dynamic pressure bearing of the present embodiment, a hydrogenated amorphous diamond layer that can be removed by a low-power laser beam is used as a corrosion-resistant coating in etching, so that the substrate is smoothened without damaging the substrate. Thus, the substrate can be etched with good precision by etching to form a dynamic pressure generating groove. According to the dynamic pressure bearing manufacturing method of the present embodiment, a hydrogenated amorphous diamond layer formed as a corrosion-resistant film when forming a dynamic pressure generating groove in etching,
Since it is used as it is as a protective lubricating film without being removed, a member with little wear can be manufactured in a small number of steps.

According to the dynamic pressure bearing manufacturing method of this embodiment, the hydrogenated amorphous diamond layer is removed by laser light, and the substrate is etched to form the dynamic pressure generating grooves. The periphery does not rise and no rework is required. According to the dynamic pressure bearing manufacturing method of the present embodiment, since the hydrogenated amorphous diamond layer is formed by the vapor phase growth method, the layer thickness can be formed to a uniform thickness with good accuracy, and the dynamic pressure The generation groove can be easily formed at a uniform depth with good accuracy, and a highly reliable dynamic pressure bearing can be obtained.

Next, a rotary polygon mirror motor as one embodiment of the motor of the present invention will be described. FIG. 6 is a sectional view showing a rotary polygon mirror motor as one embodiment of the motor of the present invention.

The rotary polygon mirror motor 30 of the present embodiment includes a stator, a rotor, and a dynamic pressure bearing as one embodiment of the dynamic pressure bearing of the present invention. Fig. 6
As shown in FIG. 5, a base 32 on which a fixed shaft 31 is erected, a resin printed board 34 screwed to the base 32 and disposed above the base 32, and a current from the printed board 34. A coreless armature coil 33 to be supplied and a yoke 36 forming a magnetic path of a magnetic force generated by the coreless armature coil 33 are provided. The coreless armature coil 33 is fixed to the surface of the printed circuit board 34 on the base 32 side, and the yoke 36 is fixed to the base 32 and faces the coreless armature coil 33. An insulating sheet 35 is sandwiched between the coreless armature coil 33 and the yoke 36.

The dynamic pressure bearing 10 includes an outer cylinder member 11, a hollow inner column member 12, an upper thrust plate 13, and a lower thrust plate 14. The inner column member 12 has a hollow portion, Except that the thrust plate 13 and the lower thrust plate 14 each have a fitting hole at the center, it is the same as the dynamic pressure bearing of the above-described embodiment. A hydrogenated amorphous diamond layer 12b, 13b, 14b is formed on the outer peripheral surface of the inner column member 12 and the surface of the two thrust plates 13, 14 facing the outer cylindrical member 11, and the hydrogenated amorphous diamond layer 12b is formed.
A dynamic pressure generating groove is formed up to the base material on which b, 13b, and 14b are formed.

Then, the hollow portion of the inner column member 12, the fitting hole of the upper thrust plate 13, the lower thrust plate 1
The fixed shaft 31 is inserted into the fitting hole of the fixed shaft 31, and the screw portion 31 of the fixed shaft 31 is provided above the upper thrust plate 13.
The upper thrust plate 13, the inner column member 12, and the lower thrust plate 14 are fixed to the screw portion 11 a and the base 12 by screwing the nut 52 to a. Outer cylinder member 1
Numeral 1 is mounted around the inner column member 12 coaxially with the fixed shaft 31 and is rotatable around the axis with respect to the inner column member 12 between the upper thrust plate 13 and the lower thrust plate 14. Is sandwiched between.

The rotor has a support member 21 fixed to the outer cylinder member 11 and a rotor magnet 22 fixed to the support member 21. A rotary polygon mirror 40 is fixed on the support member 21. Have been. The rotor magnet 22 is fixed to the coreless armature coil 33 by the fixed shaft 3.
They are arranged to face each other in one axial direction. Then, the rotor magnet 22 is urged by the rotating magnetic field formed by the coreless armature coil 33 and the yoke 36, and rotates around the axis of the fixed shaft.

Since the rotary polygon mirror motor 30 of the present embodiment having the above-described configuration includes the dynamic pressure bearing 10 of the above-described embodiment, the outer cylindrical member 11 such as a magnet floats at low speed rotation. Good durability can be obtained without a floating means.

FIG. 7 is a schematic view of a principal part showing a laser printer as one embodiment of the rotating body device of the present invention. As shown in FIG. 7, in the present embodiment, the rotating polygon mirror motor 30 shown in FIG.
Reflecting mirror 64, laser light source RS, and photosensitive drum D
M, and the laser light R from the laser light source RS
Is reflected by the rotating polygon mirror 40 of the rotating polygon mirror motor 1 and scans in the radial direction, and is reflected by the reflecting mirror 64 while adjusting the focal point by the imaging lenses 62 and 63, so that the photosensitive drum D
M is irradiated while scanning in the axial direction of the photosensitive drum DM. Then, in the laser printer, an electrostatic latent image is formed on the photosensitive drum DM by irradiation of the laser beam R,
Toner is attached to the latent image by a developing device (not shown), the toner image is transferred to a transfer sheet such as paper by a transfer device, and further fused and fixed by a fixing device, thereby completing the formation of one image.

It should be noted that the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist of the present invention.

For example, in the above embodiment, the hydrogenated amorphous diamond layers 12b, 13b, 14b
Is directly laminated on the surface of the base material of the inner column member 12 and the thrust plates 13 and 14, but a heat insulating layer is formed on the surface of the base material, and the hydrogenated amorphous diamond layers 12b, 13b and 14b May be formed. By providing such a heat insulating layer, the hydrogenated amorphous diamond layer 1 corresponding to the dynamic pressure generating groove by the laser beam is provided.
When removing 2b, 13b, and 14b, heat can be prevented from being conducted to the base material and dissipated, and the hydrogenated amorphous diamond layers 12b, 13b, and 14b can be removed efficiently. Hydrogenated amorphous diamond layer 12
b, 13b and 14b can be removed with an output of several watts (in the case of a carbon dioxide laser having a wavelength λ = 10.6 μm) when the layer thickness is 2 to 3 μm, but when the layer thickness becomes 1 μm or less, Heat generation in the layer is not sufficient and heat dissipation in the base material is increased, and an output of about 20 watts is required.
However, by providing this heat insulating layer, even if the layer thickness is extremely thin, the hydrogenated amorphous diamond layers 12b, 1
3b and 14b can be efficiently removed.

As the heat insulating layer, silicon monoxide (Si
O), silicon dioxide (SiO2), chromium oxide (Cr2
O3), aluminum oxide (Al203), silicon nitride (Si3N4) and the like. When the heat insulating layer is formed of silicon monoxide (SiO) or silicon dioxide (SiO2), the heat insulating layer preferably has a thickness of 30 to 100 nm. When the above-described heat insulating layer is provided, a heat insulating layer is formed on a base material by a vapor phase growth method, and then a hydrogenated amorphous diamond layer is formed. And
After removing the hydrogenated amorphous diamond layer corresponding to the dynamic pressure generating groove pattern by laser light, the exposed heat insulating layer is removed by chemical treatment such as etching, and then the dynamic pressure generating groove is formed on the substrate by the etching solution described above. Is etched.
The heat insulating layer is made of silicon monoxide (SiO) or silicon dioxide (Si
In the case of O2), this heat insulating layer can be removed by an aqueous solution containing hydrogen fluoride (HF) and nitric acid (HNO3).

Hydrogenated amorphous diamond layer 12
Absorbing layers may be laminated between b, 13b, 14b and the substrate or on the surfaces of the hydrogenated amorphous diamond layers 12b, 13b, 14b. By providing such a light absorbing layer, it becomes possible to more effectively absorb the laser beam and efficiently remove the hydrogenated amorphous diamond layer in accordance with the dynamic pressure generating groove pattern. This light absorbing layer preferably has a thickness of 50 nm or less. Above 50 nm
This is because the laser light is reflected. This light absorbing layer
Chromium film, tungsten film, molybdenum film, nickel
A chromium film or the like can be used, and the chromium film is preferably laminated on the surfaces of the hydrogenated amorphous diamond layers 12b, 13b, and 14b. This is because it can be removed during the etching process by the etching solution. Since the chromium film may be oxidized to form chromium oxide and erode the substrate, it is desirable to completely remove the chromium film after the formation of the dynamic pressure generation groove pattern. , 13b, 14b.

In this embodiment, the entire surface of the base material is coated to form the hydrogenated amorphous diamond layers 12b, 1b.
After forming the dynamic pressure generating grooves after forming the 3b and 14b, the hydrogenated amorphous diamond layers 12b, 13b and 14b are formed in portions other than the dynamic pressure generating grooves after forming the dynamic pressure generating grooves in the base material. May be.

In this embodiment, the hydrogenated amorphous diamond layers 12b, 13b and 14 are formed on the surface of the base material by a vapor phase growth method such as a plasma CVD method or a sputtering method.
Although the film b is formed, it is not limited to this, but may be formed by vapor deposition, coating, spraying, rubbing, or the like. However, a vapor phase growth method is preferable because a layer can be formed with a uniform thickness. As a rubbing method, hydrogenated amorphous diamond powder is sprayed on the surface of the base material, pressed from above using a plate-shaped or rod-shaped pressed body, and slid or rotated to rub the hydrogenated amorphous diamond powder on the base material. A method for forming a hydrogenated amorphous diamond film by pressurizing, or a method for forming a hydrogenated amorphous diamond film on a press body in advance by a plasma CVD method or the like, and pressing the hydrogenated amorphous diamond film-formed press body against a substrate surface from above. A method of sliding or rotating is exemplified.

In the above-described embodiment, the dynamic pressure bearings are employed in both the radial direction and the thrust direction. However, even if one is a slide bearing, a roller bearing, or a ball bearing, the other is a dynamic pressure bearing. The effect of the present invention on the bearing can be obtained. Further, in the above-described embodiment, a hollow outer cylinder member is used as the outer column member. However, when used as a bearing only in the thrust direction or when the radial direction is supported from the outside, a solid An outer pillar member can also be used.

In the above-described embodiment, the dynamic pressure generating grooves for generating the dynamic pressure in the thrust direction are formed in the thrust plates 13 and 14, but instead of or together with the thrust plates 13, 14. It may be formed on the end face. In addition, the dynamic pressure generating groove is not limited to the herringbone groove, and may be a spiral groove or any other groove having various shapes. In the above-described embodiment, the dynamic pressure generating groove generates a dynamic pressure in the radial direction. Pressure generating groove for the inner column member 12
Is formed on the outer circumferential surface of the outer cylindrical member 11 instead of or together with the outer circumferential surface. Further, the shape of the dynamic pressure generating groove is not limited to the oblique line shape, but may be a spiral groove, a herringbone groove, or another shape.

The method of manufacturing the dynamic pressure bearing is not limited to the above-described method, and the dynamic pressure generating groove pattern forming apparatus 2 is not limited to the above-described apparatus. For example, in the dynamic pressure generating groove pattern forming apparatus 2, a polygon mirror may be used instead of the galvanometer mirror 5. Also,
The laser oscillation device 3 includes a carbon dioxide gas laser, a YAG laser,
Although an argon laser or the like can be used, a carbon dioxide gas laser or an argon laser is preferable when the laser wavelength is about 1 μm because the laser light easily passes through the hydrogenated amorphous diamond layer and hardly generates heat.

The dynamic pressure bearing 10 of the present invention can be applied to various disk devices such as hard disk drives and CD-ROM drives, rotary polygon mirror devices, and spindle motors of other rotating devices.

[0059]

As described above, according to the dynamic pressure bearing, the dynamic pressure bearing manufacturing method, the motor, and the rotating body device according to the present invention, good durability of each member is maintained, and processing is easy and low. Manufacturing at a cost becomes possible.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of a dynamic pressure bearing of the present invention.

2 is a diagram showing an inner column member of the dynamic pressure bearing of FIG. 1,
(A) is a sectional view, and (b) is a side view.

FIG. 3 is a plan view showing a surface of a lower thrust plate of the dynamic pressure bearing of FIG. 1 facing an outer cylindrical member;

FIG. 4 is an explanatory view showing a manufacturing process for an inner column member of the dynamic pressure bearing in one embodiment of the dynamic pressure bearing manufacturing method of the present invention.

FIG. 5 is a schematic configuration diagram showing a dynamic pressure generating groove pattern forming apparatus used in the method of manufacturing a dynamic pressure bearing according to the embodiment of FIG. 4;

FIG. 6 is a sectional view showing a rotary polygon mirror motor as one embodiment of the motor of the present invention.

FIG. 7 is a schematic configuration diagram showing a laser printer as one embodiment of the rotating device of the present invention.

[Explanation of symbols]

 2 Dynamic pressure generating groove pattern forming device 3 Laser oscillation device 4 Condensing lens 5 Galvanometer mirror 6 Mounting table 8 Airtight system 9 Oxygen cylinder 10 Dynamic pressure bearing 11 Outer tube member 12 Inner column member 12a base material 12b Hydrogenated amorphous diamond layer 12c Dynamic pressure generating groove 13 Upper thrust plate 13b Hydrogenated amorphous diamond layer 14 Lower thrust plate 14b Hydrogenated amorphous diamond layer 14c Dynamic pressure generating groove

Continuation of the front page (72) Inventor Yutaka Koyama 1-8-8 Nakase, Mihama-ku, Chiba-shi, Chiba F-term in Seiko Instruments Inc. KK06

Claims (12)

[Claims] A cylindrical outer cylinder member having a hollow portion; a hollow or solid inner column member fitted in the hollow portion and rotating relative to the outer cylinder member; and the outer cylinder member And a dynamic pressure generation groove formed in one of the opposing surfaces of the inner column member, wherein the outer cylinder member and the inner column member in which the dynamic pressure generation groove is formed are provided. A hydrogenated amorphous diamond layer is formed on the facing surface, and the dynamic pressure generating groove is formed so as to extend to the inside of the substrate on which the hydrogenated amorphous diamond layer is formed. bearing. 2. A hollow or solid outer column member, a thrust plate facing an end face of the outer column member and rotating relatively to the outer column member, and A dynamic pressure generating groove formed in one of the opposing surfaces, and a hydrogenated amorphous diamond layer on the opposing surface of the outer column member and the thrust plate in which the dynamic pressure generating groove is formed. The dynamic pressure generating groove is formed so as to extend to the inside of the substrate on which the hydrogenated amorphous diamond layer is formed. 3. The dynamic pressure bearing according to claim 1, wherein the hydrogenated amorphous diamond layer has a thickness of 2 μm or less. 4. A heat insulating layer is provided between the substrate on which the dynamic pressure generating grooves are formed and the hydrogenated amorphous diamond layer. The dynamic pressure bearing according to claim 1. 5. A DLC layer forming step of uniformly forming a hydrogenated amorphous diamond layer on a surface of the substrate on which the dynamic pressure generating groove is formed, and after the DLC layer forming step, the DLC layer forming step is performed. A pattern forming step of removing the diamond layer according to the pattern of the dynamic pressure generating groove; and, after the pattern forming step, an etching step of engraving the dynamic pressure generating groove on the exposed surface of the base material by wet etching. The method for manufacturing a dynamic pressure bearing according to any one of claims 1 to 4, comprising: 6. The dynamic pressure bearing manufacturing method according to claim 5, wherein in the DLC layer forming step, the hydrogenated amorphous diamond layer is formed on the surface of the base material by a vapor phase growth method. 7. The dynamic pressure bearing according to claim 5, wherein in the DLC layer forming step, the hydrogenated amorphous diamond layer is formed to have a thickness of 2 μm or less. Production method. 8. The dynamic pressure bearing according to claim 5, wherein in the pattern forming step, the hydrogenated amorphous diamond layer is removed by a laser beam. Production method. 9. A heat-insulating layer forming step of uniformly forming a heat-insulating layer made of a heat-insulating material on a surface of the substrate on which the dynamic pressure generating groove is formed, wherein the DLC layer forming step includes the heat-insulating layer. After the forming step, a hydrogenated amorphous diamond layer is laminated on the heat insulating layer, and the etching step removes the exposed heat insulating layer after the pattern forming step and exposes the base material according to the pattern. 9. The method according to claim 8, wherein the dynamic pressure generating groove is engraved on the exposed surface of the base material by wet etching. 10. A light-absorbing layer forming step of laminating a light-absorbing layer having a better absorbance of laser light on the hydrogenated amorphous diamond layer formed by the DLC layer forming step than the hydrogenated amorphous diamond layer. 10. The dynamic pressure bearing manufacturing method according to claim 8, wherein the pattern forming step includes removing the light absorbing layer and the hydrogenated amorphous diamond layer. 11. A motor comprising the dynamic pressure bearing according to claim 1. Description: 12. A rotating body device comprising the motor according to claim 11.