JP2000002236A - Dynamic pressure bearing, spindle motor and rotor device with the bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent dispersion and flowage of a lubricant mist in a dynamic hydraulic pressure bearing so as to prevent damage of a spindle motor using the dynamic hydraulic pressure bearing. SOLUTION: This dynamic hydraulic pressure bearing comprises a tube-like member 30, a shaft like member 20 rotatably provided to the tube-like member 30, a blockade member 50 fixed to the shaft-like member 20, and a lubricating oil filled in a gap between the tube-like member 30 and the shaft-like member 20. In this dynamic hydraulic pressure bearing, a dynamic air pressure generation groove 12 for gathering a lubricant mist toward a rotation center is formed on a lower face of the blockade member 50.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing for holding a member rotating at a high speed with respect to a fixed member via a lubricating material, and more particularly to a dynamic pressure bearing for holding a rotating member in a non-contact manner. The present invention relates to a spindle motor using a dynamic pressure bearing, and a rotating device including the spindle motor as a driving source of the rotating body.

[0002]

2. Description of the Related Art Rotating devices such as a magnetic disk device, an optical disk device, and a scanner including a polygon mirror include:
2. Description of the Related Art A spindle motor having a dynamic pressure bearing, which is a non-contact bearing, is widely used as a drive source of a rotating body such as a magnetic disk, an optical disk, and a polygon mirror. Since the dynamic pressure bearing rotates in a non-contact manner during the rated rotation, the dynamic pressure bearing does not have rotation unevenness or vibration caused by the bearing, and has excellent characteristics of high-speed durability.

[0003] The dynamic pressure bearings are roughly classified into air dynamic pressure bearings and liquid dynamic pressure bearings. Air dynamic pressure bearings do not use lubricants such as oil, so that the surface of rotating bodies such as magnetic disks can be kept clean from oil contamination etc., and widely used in rotating devices that rotate these magnetic disks etc. Used. However, the air dynamic pressure bearing has extremely low bearing stiffness and the clearance between the bearings is on the order of several microns. Also, it is difficult to obtain a sufficient air dynamic pressure in a low-speed rotation range. On the other hand, a liquid dynamic pressure bearing has a high bearing rigidity and is relatively easy to manufacture. In particular, a sufficient dynamic pressure can be obtained even at a low speed of about several thousand rotations.

[0004]

When a rotating device such as a magnetic disk is constructed using a liquid dynamic pressure bearing, lubricating oil as a lubricating material may be scattered in a mist. For example, when mist of lubricating oil is scattered in a magnetic disk device such as a hard disk, and the lubricating oil adheres to the surface of the disk, the adhering oil interferes with the head of the hard disk and the hard disk itself. May be damaged. In addition, such evaporation of the lubricating oil reduces the total amount of the lubricating oil, causing problems such as poor generation of dynamic pressure and shortening of the life of the bearing which is a rotating member.

As one measure for solving such a problem of lubricating oil scattering, a plurality of flange-shaped plates are formed so as to protrude above the liquid surface of the lubricating oil, and the flow of the mist of the lubricating oil is controlled. There is a structure in which the scattering of lubricating oil is suppressed by shielding with a plate. However, forming a plurality of flange-shaped plates in a narrow space in a protruding manner requires high processing accuracy and is difficult to manufacture, resulting in an increase in manufacturing cost.

The present invention solves the above-mentioned drawbacks of the prior art, and does not require any troublesome processing to prevent the scattering of lubricating materials such as lubricating oil and to prevent damage to the rotating body device. The purpose is to provide pressure bearings.

[0007]

SUMMARY OF THE INVENTION A dynamic pressure bearing according to the present invention comprises a shaft member having a shaft, a cylindrical member provided with a fitting portion into which the shaft is fitted, and an upper end of the cylindrical member. A closing member that closes the shaft member, and one of the shaft member and the cylindrical member is driven so as to rotate, and a gap between the cylindrical member and the fitted shaft member. Wherein a fluid dynamic pressure generating portion is formed in the gap and the gap is filled with a lubricating material, wherein an air dynamic pressure generating portion is formed near an interface of the lubricating material. As an example of the dynamic pressure bearing of the present invention, the closing member forms a gap between the upper end of the cylindrical or shaft-shaped member, and on the surface of the cylindrical or shaft-shaped member or the closing member, An air dynamic pressure generating portion is formed facing the gap. The air dynamic pressure generating section is, for example, an air dynamic pressure generating groove in which a plurality of grooves are provided on a surface of a member to be formed, and a member that rotates among the shaft member, the cylindrical member, and the closing member, and Formed on both or one surface of the non-rotating member. The present invention
Furthermore, the present invention also includes a rotating body device including a spindle motor having the dynamic pressure bearing as a bearing, and further including the spindle motor as a driving source of the rotating body. Further, a bearing as another aspect of the present invention is a bearing in which a rotating member and a fixed member are combined, and a gap between the rotating member and the fixed member is filled with a lubricating material, and a mist of the lubricating material is formed. An air dynamic pressure generating portion that is collected near the center of rotation is formed near the interface of the lubricating material. Examples of the lubricating material filled in the gap include lubricating oil and grease. When lubricating oil is used as a lubricating material, an oil reservoir for storing lubricating oil can be formed in a part of the gap.

[0008]

1 and 2 are views for explaining a rotary shaft type spindle motor according to an embodiment of the present invention. FIG. 1 is a sectional view of the rotary shaft type spindle motor, and FIG. It is sectional drawing which expands and shows a principal part. The spindle motor 1 of the present embodiment has a disc-shaped fixed base 10 for cutting the spindle motor 1 itself.
And a substantially cylindrical metal shaft member 20 composed of a rotating shaft portion 23 and having a flange portion 21 substantially in the middle in the height direction.
A cylindrical member 30 fixed to the fixing base 10 and provided with a fitting portion 31 for fitting the shaft member, and a closing member 50 forming a part of a rotor and fixed to the shaft member 20. Have. A stator coil 70 is formed on the outer peripheral portion of the tubular member 30, and the stator magnet 70 and a rotor magnet 60 which is a part of a rotor and is formed on an inner peripheral portion obtained by bending an outer edge of the closing member 50 are arranged close to each other. And confront each other. An air dynamic pressure generating groove 12 is formed on the lower surface of the closing member 50 so as to function as an air dynamic pressure generating unit to prevent the lubricating oil from scattering outside the spindle motor. The air dynamic pressure generating groove 12 does not need to be provided on the entire lower surface of the closing member 50, but may be provided near the periphery of the shaft member 20.

The shaft-shaped member 20 has a flange portion 21 functioning as a thrust bearing. That is, in the flange portion 21 protruding from the shaft portion 23 in a flange shape, the upper surface 24 and the lower surface 25 face the inner peripheral portion of the tubular member 30 described below with a small gap, and the upper and lower surfaces 24, 25 and A fluid dynamic pressure generating groove (not shown) is formed in one or both of the inner peripheral portions of the opposed cylindrical member 30. The dynamic pressure generating groove generates a liquid dynamic pressure during rated rotation, and maintains the axial position of the shaft member 20 in a non-contact state. A cylindrical portion 22 for a dynamic pressure bearing is formed below the flange portion 21 of the shaft member 20. The outer peripheral surface 26 of the dynamic pressure bearing cylindrical portion 22 is
It faces a later-described inner peripheral portion of the tubular member 30 with a small gap. Similarly, the bottom surface 27 of the dynamic pressure bearing cylindrical portion 22 is opposed to an inner peripheral portion of a tubular member 30 described later with a small gap. Fluid dynamic pressure generating grooves (not shown) are formed on one or both of the opposing surfaces on the outer peripheral surface 26 and the bottom surface 27 of the dynamic pressure bearing cylindrical portion 22 and the inner peripheral portion of the cylindrical member 30. The grooves generate liquid dynamic pressure at the time of rated rotation, and maintain the circumferential and axial positions of the shaft member 20 in a non-contact manner.

As described above, the shaft-like member 20 having a structure in which the substantially entire peripheral portion facing the cylindrical member 30 contributes to the generation of dynamic pressure.
A ring-shaped groove 28 is formed at a connecting portion between the shaft portion 23 and the upper surface 24 of the flange portion 21, and a ring-shaped groove 29 is formed at a connecting portion between the shaft portion 23 and the lower surface 25 of the flange portion 21. You. These ring-shaped grooves 28 and 29 respectively form spaces continuous with the gap between the inner peripheral portion of the cylindrical member 30 and the shaft-shaped member 20, and lubricating oil as a medium for forming a liquid dynamic pressure is introduced into the spaces. Is done.

The cylindrical member 30 is fitted and fixed in a circular hole provided at the center of the fixed base 10. At the center of the tubular member 30, there is provided a fitting portion 31 which is an inner peripheral portion of the tubular member 30 for fitting the shaft-shaped member 20 and holding it in a non-contact state during rated rotation. More specifically, the fitting portion 31 includes a bottom surface 32 facing the bottom surface 27 of the dynamic pressure bearing cylindrical portion 22, a side surface 35 facing the outer peripheral surface 26 of the dynamic pressure bearing cylindrical portion 22, and a lower surface of the flange portion 21. A large-diameter portion having a flange-facing lower surface 33 facing the upper surface 25 and a flange-facing upper surface 34 facing the upper surface 24 of the flange portion 21, and particularly having a larger diameter in a portion corresponding to the flange portion 21. 36.

The lower surface 33 facing the flange in the large diameter portion 36
A ring-shaped groove 37 extending in a ring shape and functioning as an oil sump for storing lubricating oil is formed at the outer edge of the lubrication oil. This ring-shaped groove 37, together with the other ring-shaped grooves 28 and 29, prevents oil shortage and bubbles from being generated on the oil drawing side of the thrust dynamic pressure generating groove at the time of rated rotation, and stably rotates the shaft-shaped member 20. Make it work. The corner 38 between the bottom surface 32 and the side surface 35 also functions as an oil reservoir. The corner portion 38 can generate a high radial dynamic pressure in the radial dynamic pressure generating groove at the time of rated rotation, so that stable high-speed rotation can be obtained even under a large load.

In order to easily form the large-diameter portion 36 on the cylindrical member 30, a thrust holding member 40 is fixed to the upper end of the cylindrical member 30 after the large-diameter portion 36 is formed. The thrust holding member 40 is a disc-shaped member having an inner diameter hole through which the shaft-shaped member 20 is inserted at the center, and a bottom surface facing the flange portion 21 is an upper surface 24 of the flange portion 21.
And an upper surface 34 facing the flange. The thrust pressing member 40 is formed by forming a hole for the large-diameter portion 36 corresponding to the flange portion 21 in the cylindrical member 30 and then forming the shaft-shaped member 20.
And the shaft portion 23 of the shaft-shaped member 20 is fixedly inserted into the bore of the thrust holding member 40 so as to close the hole of the large-diameter portion 36.

As described above, the shaft-shaped member 2 at the time of rated rotation
In order to keep the circumferential and axial positions of 0 in non-contact,
A liquid dynamic pressure generating groove is formed in a minute gap between the shaft member 20 and the cylindrical member 30. The size of these minute gaps is about 4 to 20 microns, and an appropriate value is selected at the time of design. The thrust dynamic pressure generating groove includes: 1) one or both surfaces of the bottom surface 27 of the dynamic pressure bearing cylindrical portion 22 and the bottom surface 32 of the fitting portion 31 of the cylindrical member 30; One or both surfaces of the lower surface 25 of the
3) Further, it is formed on the upper surface 24 of the flange portion 21 and one or both surfaces of the flange-facing upper surface 34 opposed thereto. The radial dynamic pressure generating groove is formed on one or both surfaces of the outer peripheral surface 26 of the cylindrical portion 22 for the dynamic pressure bearing and the side surface 35 of the fitting portion 31. As will be described later, the shaft member 20 and the cylindrical member 30
The lubricating oil is introduced into the minute gap between the shafts, and the liquid dynamic pressure is generated from the liquid dynamic pressure generating groove during the rated rotation of the shaft-shaped member 20.

An oil reservoir 41 is formed in the inner diameter hole of the thrust holding member 40. This inner diameter hole has a smaller diameter on the lower side and a larger diameter on the upper side by cutting, and has a truncated conical cross section. A gap between the thrust holding member 40 having a large diameter on the upper side and the shaft portion 23 of the shaft member 20 is used as an oil reservoir 41. The bottom of the oil reservoir 41 communicates with the ring-shaped groove 28,
Further, the flange portion 21 is formed through the ring-shaped groove 28.
And the gap between the thrust holding member 40 and the thrust holding member 40. The upper end side of the oil reservoir 41 is open to the atmosphere. As described above, since the upper end of the oil reservoir 41 has a large diameter and is opened to the atmosphere, even when the lubricating oil expands due to ambient temperature, pressure, or the like, the liquid surface is formed on the upper end side of the oil reservoir 41. The lubricating oil does not leak to the outside of the bearing just by moving slightly.

The lubricating oil for generating the liquid dynamic pressure is applied to the shaft member 20 and the cylindrical member 30 by a vacuum injection method, a dropping method, or the like.
Is introduced into the gap between. That is, the gap between the bottom surface 27 of the dynamic pressure bearing cylindrical portion 22 and the bottom surface 32 of the fitting portion 31 of the tubular member 30, the outer peripheral surface 2 of the dynamic pressure bearing cylindrical portion 22.
6, a gap between the side surface 35 of the fitting portion 31, a gap between the lower surface 25 of the flange portion 21 and a flange-facing lower surface 33 facing the same, and a gap between the upper surface 24 of the flange portion 21 and the flange facing the same. Lubricating oil is introduced so as to fill the gap between the upper surfaces 34, and further fills the ring-shaped grooves 28, 29, and 37 functioning as oil reservoirs, fills the corners 38, and furthermore, fills the level of the lubricating oil. Is filled so as to be located in the oil reservoir 41 opened obliquely. The lubricating oil contacts the respective dynamic pressure generating grooves formed in these gaps to generate liquid dynamic pressure.

In this embodiment, such a dynamic pressure bearing which rotates in a non-contact manner by the liquid dynamic pressure is incorporated in the spindle motor 1. The spindle motor 1 includes a closing member 50 constituting a rotor and a closing member 50 of the closing member 50. A rotor magnet 60 formed on an inner peripheral portion of which an outer edge is bent, and a stator coil 70 which is close to and opposed to the rotor magnet 60 are provided. That is, the spindle motor 1 of the present embodiment is a rotary shaft type spindle motor in which the rotor is supported on the stator by the liquid dynamic bearing. In the spindle motor 1, when the start switch of the motor is turned on, a current flows through the stator coil 70, and the rotor rotates in a fixed direction due to interference between the magnetic field generated by the current and the magnetic field of the rotor magnet 60.

The closing member 50 constituting the rotor that starts rotating by passing an electric current is a disk-shaped member. The upper end of the shaft member 20 is fixed to a hole provided at the center of the closing member 50. And this closing member 5
0 on the lower surface 51 near the shaft-shaped member 20,
An air dynamic pressure generating groove 12 is formed. This closing member 5
0 is located so as to form a narrow space facing the thrust holding member 40, but a space surrounded by the upper end of the thrust holding member 40, the lower surface 51 of the closing member 50, and the outer periphery of the shaft portion 23. The oil reservoir 41 communicates with the atmosphere, and the air dynamic pressure generating groove 12 is formed facing this space.

FIGS. 3 to 5 show the air dynamic pressure generating groove forming portion. As shown in FIG. 3, the air dynamic pressure generating groove 12 is formed with a plurality of grooves for generating air dynamic pressure. The groove shown in FIG. 3 is a so-called herringbone-shaped air dynamic pressure generation groove 12 in which a plurality of substantially L-shaped grooves 13 are connected in one direction. This air dynamic pressure generating groove 12
Thus, at the time of the rated rotation of the rotor, the air flow is collected near the center of rotation, that is, near the center of the periphery of the shaft member 20 at the position above the oil reservoir 41, and the air dynamic pressure is generated. As a result, when the mist of the lubricating oil scatters from the level of the oil reservoir 41 due to factors such as pressure and temperature,
The mist is collected near the center of the periphery of the shaft member 20 at the position above the oil reservoir according to the airflow, and stays there. This prevents the mist of the lubricating oil from scattering and flowing outside the bearing. The mist of the lubricating oil staying at the position above the oil reservoir gradually adheres to the air dynamic pressure generating groove 12 when the amount of the lubricant increases, and drops into the oil reservoir 41 when the amount of the lubricant increases. Even when the lubricating oil evaporates in this way, it is effectively reduced, so that it is possible to prevent the lubricating oil from decreasing and prolong the life of the spindle motor.

The air dynamic pressure generating groove 12 is not limited to the so-called herringbone shape shown in FIG. 3, but may have another shape. 4 and 5 show other shapes. FIG. 4 shows an example of a so-called spiral dynamic pressure generating groove.
Has a shape that shifts more in the circumferential direction as the distance from the center increases. FIG. 5 shows an example of a dynamic pressure generating groove having a linear groove 15 extending in the radial direction. The most appropriate pattern for the shape of the air dynamic pressure generating groove 12 is selected at the design stage. If it is not necessary to arrange them in a circular shape, other shapes such as a square, a triangle, and a plurality of circular arcs may be used.
The air dynamic pressure generating groove 12 is formed by stamping (rolling) on the lower surface 51 of the closing member 50, or by various methods such as printing and etching. For example, in the method of stamping and stamping a mold, the lower surface 51 can be processed relatively easily to form the air dynamic pressure generating groove 12, and therefore, there is no problem that the processing is complicated.

The air dynamic pressure generating groove 12 can be formed so as to have a groove 16 recessed from the lower surface 51 of the closing member 50 as shown in FIG. 6, and as shown in FIG. Projecting portion 17 that protrudes from the lower surface 51 can be formed. Whether to form the concave groove by shaving or to form the protruding ridge portion is selected in consideration of easiness of fabrication at the design stage.

FIG. 8 shows a rotary device employing the spindle motor 1 of the present embodiment. This rotating device is a magnetic disk device 5 in which a plurality of rotating magnetic disks 3 are attached to the above-described spindle motor 1, and each magnetic head 4 faces each magnetic disk 3. In the spindle motor 1 of the present embodiment, the air dynamic pressure generator 12
As a result, the mist of the lubricating oil is prevented from being scattered, so that the magnetic disk device 5 is not damaged by the lubricating oil. The dynamic pressure bearing of the present invention is not limited to a magnetic disk device, but can be applied to other optical disk devices, magneto-optical disk devices, polygon mirror devices, and precision small rotating devices.

FIGS. 9 to 11 show examples of forming other dynamic pressure generating portions. FIG. 9 shows an example of a fixed shaft type dynamic pressure bearing. The shaft member 83 is a fixed member, and a cylindrical member 84 having a structure in which the shaft member 83 is fitted rotates around the shaft member 83. A minute gap is formed between the cylindrical member 84 and the shaft member 83, and the gap is filled with lubricating oil so as to form a liquid dynamic bearing. A closing member 81 is formed on the upper end side of the cylindrical member 84 and the shaft member 83 to close them, and the closing member 81 rotates together with the cylindrical member 84. On the lower surface of the closing member 81, an air dynamic pressure generating groove 82 is provided in a disk shape with a center notched. The specific groove shape of the air dynamic pressure generating groove 82 can be selected from various types shown in FIGS. 3 to 5 and other types. The air dynamic pressure generating groove 82 collects the air flow containing the lubricating oil mist near the center of rotation, and suppresses the flow to the outside of the bearing, so that the mist of the lubricating oil can be prevented from scattering.

FIG. 10 shows an example of a rotating shaft type dynamic pressure bearing. The shaft-like member 85 that operates by rotating is held in a non-contact manner at the time of high-speed rotation by the cylindrical member 86 by a fluid dynamic bearing. The gap between the shaft member 85 and the cylindrical member 86 is filled with lubricating oil by a required method. A closing member 87 is formed on the upper end sides of the shaft member 85 and the cylindrical member 86. A space is formed between the lower surface of the closing member 87 and the upper ends of the shaft member 85 and the cylindrical member 86, and the shaft member 8
At the upper end of 5, an air dynamic pressure generating groove 88 for collecting the mist of the lubricating oil near the center of rotation is formed.

FIG. 11 shows an example of a fixed shaft type dynamic pressure bearing. The shaft member 89 is a member to be fixed, and the cylindrical member 90 having a structure into which the shaft member 89 is fitted is the shaft member 8.
Rotate around 9. These shaft member 89 and cylindrical member 9
The gap between 0 is filled with lubricating oil by a required method. On the upper end side of the shaft-like member 89 and the cylindrical member 90,
The closing member 91 is formed. A space is formed between the lower surface of the closing member 91 and the upper ends of the shaft member 89 and the cylindrical member 90, and the air dynamic pressure generating groove for collecting the mist of the lubricating oil near the center of rotation is formed at the upper end of the cylindrical member 90. 92 are formed.

The dynamic pressure bearings shown in FIG. 2 and FIGS. 9 to 11 have the air dynamic pressure generating grooves 12, 82, 88, 92 for collecting the mist of the lubricating oil near the center of rotation, respectively, only on one side of the narrow space. However, for example, the air dynamic pressure generating grooves 12, 82, 88, 92 are also formed on opposing surfaces,
It is also possible to adopt a configuration in which air dynamic pressure generating grooves exist on both sides of the space.

The bearing of the present invention is applicable to bearings other than dynamic pressure bearings. The bearing of the present invention has a
The present invention can be applied to both plain bearings and ball bearings. Further, in the above-described embodiments, lubricating oil has been described as a lubricating material. However, the present invention is not limited to lubricating oil, and can be similarly applied to other materials such as grease.

[0028]

According to the dynamic pressure bearing of the present invention, an air dynamic pressure generating portion for preventing the mist of the lubricating material from being scattered to the outside of the device such as a spindle motor is formed near the interface of the lubricating material. The mist of the lubricating material can be prevented from scattering outside the bearing. Therefore, by using the present invention,
An adverse effect such as damage to the rotating body due to the adhesion of the lubricating material can be prevented. Further, the lubrication material is not reduced, and the bearing itself can have a long life.

Further, the air dynamic pressure generating portion itself can be relatively easily manufactured by rolling or the like. By applying the present invention, the manufacturing cost does not increase due to processing, and the rotating body device can be manufactured. Obtainable.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of one embodiment of a spindle motor provided with a dynamic pressure bearing of the present invention.

FIG. 2 is an enlarged sectional view showing a main part of the spindle motor of FIG. 1 in an enlarged manner.

FIG. 3 is a plan view of a so-called herringbone type dynamic pressure generating groove, which is an example of a shape of an air dynamic pressure generating groove of the spindle motor.

FIG. 4 is a plan view of a so-called spiral type dynamic pressure generating groove, which is another example of the shape of the air dynamic pressure generating groove of the spindle motor.

FIG. 5 is a plan view of still another example of the shape of the air dynamic pressure generating groove of the spindle motor, which is a linear dynamic pressure generating groove.

FIG. 6 is an enlarged sectional view of an example of the dynamic pressure generating groove.

FIG. 7 is an enlarged sectional view of another example of the dynamic pressure generating groove.

FIG. 8 is a perspective view showing an example of a magnetic disk drive using the spindle motor as a drive source of a rotating body.

FIG. 9 is a view showing another embodiment of the dynamic pressure bearing of the present invention, and is a cross-sectional view of a shaft-fixed type dynamic pressure bearing.

FIG. 10 is a view showing an embodiment of still another dynamic pressure bearing of the present invention, and is a cross-sectional view of a shaft-rotation type dynamic pressure bearing.

FIG. 11 is a view showing still another embodiment of the dynamic pressure bearing of the present invention, and is a cross-sectional view of a shaft-fixed type dynamic pressure bearing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spindle motor 3 Magnetic disk 4 Magnetic head 5 Magnetic disk device 10 Fixed base 12 Air dynamic pressure generating groove 20 Shaft member 21 Flange part 22 Cylindrical part for dynamic pressure bearing 23 Shaft member 24 Upper surface 25 Lower surface 30 Cylindrical member 31 Fitting part 32 bottom surface 33 lower surface facing flange portion 34 upper surface facing flange portion 40 pressing member 41 oil reservoir 50 closing member

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tadao Iwaki 1-8-8 Nakase, Mihama-ku, Chiba-shi Inside Seiko Instruments Inc. (72) Inventor Naoki Kawawada 1-8-8 Nakase, Mihama-ku, Chiba-shi, Chiba Inside Iko Instruments Co., Ltd. (72) Inventor Shinichi Hayashizaki 1-8-1, Nakase, Mihama-ku, Chiba City, Chiba Prefecture Inside Inco Instruments Co., Ltd. (72) Hiromasa Shimaguchi 1-8-1, Nakase, Mihama-ku, Chiba City, Chiba Inside Instruments Co., Ltd. (72) Inventor Hiroaki Namiki 1-8, Nakase, Mihama-ku, Chiba-shi, Chiba F-term (reference) inside Seiko Instruments Co., Ltd. GA02 GA03

Claims (11)

[Claims] A shaft member having a shaft, a cylindrical member provided with a fitting portion into which the shaft is fitted, and a closing member for closing an upper end side of the cylindrical member; One of the cylindrical member or the cylindrical member is driven to rotate, and a fluid dynamic pressure generating portion is formed in a gap between the cylindrical member and the fitted shaft member, and the gap is lubricated. A dynamic pressure bearing filled with a material, wherein an air dynamic pressure generating portion is formed near an interface of the lubricating material. 2. The closing member forms a gap between the cylindrical member and an upper end of the tubular member, and an air dynamic pressure generating portion faces the gap on a surface of the cylindrical member or the closing member. The dynamic pressure bearing according to claim 1, wherein the dynamic pressure bearing is formed. 3. The closing member forms a gap between the shaft member and an upper end of the shaft member, and an air dynamic pressure generating portion faces the gap portion on a surface of the shaft member or the closing member. The dynamic pressure bearing according to claim 1, wherein the dynamic pressure bearing is formed. 4. The dynamic pressure bearing according to claim 1, wherein the air dynamic pressure generating portion comprises an air dynamic pressure generating groove provided with a plurality of grooves on a surface of a member to be formed. 5. The air dynamic pressure generating portion is formed on at least one of the rotating member and the non-rotating member among the shaft member, the cylindrical member, and the closing member. The dynamic pressure bearing according to claim 1. 6. A spindle motor comprising a bearing comprising the dynamic pressure bearing according to claim 1. 7. A rotator device comprising the spindle motor according to claim 6 as a drive source for a rotator. 8. A bearing in which a rotating member and a fixed member are combined, wherein a gap between the rotating member and the fixed member is filled with a lubricating material, and an air dynamic pressure generating portion is provided near an interface of the lubricating material. A bearing characterized in that a bearing is formed. 9. The bearing according to claim 1, wherein the lubricating material is a lubricating oil. 10. The bearing according to claim 9, wherein an oil reservoir for storing lubricating oil is formed in a part of said gap. 11. The bearing according to claim 1, wherein the lubricating material is grease.