JPH1151042A - Dynamic pressure bearing, spindle motor incorporating this bearing, and rotor device incorporating this spindle motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dynamic pressure bearing in a shape capable of forming a super abrasion resistant film made out of diamond-like carbon and the like over the surfaces of the aforesaid bearing and its haft, provide a spindle motor incorporating the aforesaid dynamic pressure bearing, and provide a rotor device incorporating the aforesaid spindle motor. SOLUTION: This air dynamic pressure bearing is in a structure where two members are sandwiched, namely they are a housing mount side upper bearing member 2 on which a shaft mounting side bearing member to be fixed to a shaft is fixed to a housing, and a housing mount side lower bearing member 3. The bearing members 1 and 2 are gradually approached to a conical surface which is tapered upward so as to be smaller in diameter, the bearing member 1 and 3 are gradually approached to a conical surface which is tapered downward so as to be smaller in diameter. And when the bearing member 1 is rotated or when the bearing members 2 and 3 are rotated, dynamic pressure is built up in a dynamic pressure generating groove provided for either one of the bearing members 1 and 2, or dynamic pressure is built up in a dynamic pressure generating groove provided for either one of the bearing members 1 and 3. A super abrasion resistant film made out of diamond-like carbon and the like is easy to be formed in the conical surface unlikely from a cylindrical hole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas dynamic pressure bearing having a shaft and a bearing surface in which an ultra-abrasion-resistant film such as diamond-like carbon is easily formed, a spindle motor employing the gas dynamic pressure bearing, and The present invention relates to a rotating device employing a spindle motor.

[0002]

2. Description of the Related Art A gas dynamic pressure bearing used in a conventional spindle motor has a shaft and a bearing surface of a gas thrust bearing formed in an annular flat pair, and a shaft and a bearing surface of a gas radial bearing have a cylindrical surface. It is even number. In order to prevent wear of the shaft and the bearing due to close contact of the dynamic pressure generating point of the gas thrust bearing at the start and stop of operation when the dynamic pressure is insufficient, the gas thrust bearing is made of a super hard material such as ceramic. Is used.

[0003]

However, since it is expensive to perform high-precision processing on a super-hard material such as ceramics, for example, a diamond-like carbon film is coated on a metal material using an ion beam mixing apparatus. Attention has been paid to vapor deposition. However, diamond-like carbon is formed into a metallic material by the force of ions, and is deposited on the outer peripheral surface and end surface of the cylindrical body. It was difficult to form.

According to the present invention, the shaft and the bearing surface are shaped so as to easily form a super wear-resistant coating such as diamond-like carbon.
A gas dynamic pressure bearing, a spindle motor employing the gas dynamic pressure bearing, and a rotating device employing the spindle motor are provided.

[0005]

According to a first aspect of the present invention, there is provided a shaft-mounting-side bearing member whose upper and lower ends are conically reduced in diameter, and an upper conical hole having an upwardly decreasing diameter. A housing-mounting-side upper bearing member installed such that a conical hole is close to an upper conical surface of the shaft-mounting-side bearing member;
A lower conical hole having a gradually decreasing diameter in a downward direction, the lower conical hole being provided on a housing mounting side lower bearing member installed so as to be close to a lower conical surface of the shaft mounting side bearing member; A dynamic pressure generating groove is provided on one of the upper conical surface of the side bearing member and the upper bearing member on the housing mounting side, and the lower conical surface of the shaft mounting side bearing member and the lower conical surface of the housing mounting side are provided. An object of the present invention is to provide a gas dynamic pressure bearing characterized in that a dynamic pressure generating groove is provided in any one of them. The second invention of the present application is characterized in that the shaft mounting side bearing member of the first invention is fixed to a shaft, and the housing mounting side upper bearing member and the housing mounting side lower bearing member are fixed to the housing. The present invention provides a spindle motor employing a gas dynamic pressure bearing.

According to a third aspect of the present invention, there is provided a rotating device employing a spindle motor, wherein a rotating object such as a polygon mirror or a magnetic disk or an optical disk is mounted on the spindle of the spindle motor according to the second aspect of the invention. Is provided.

[0007]

FIG. 1 is a longitudinal sectional view showing a gas dynamic pressure bearing according to a first embodiment of the present invention. This gas dynamic pressure bearing A has a structure in which a shaft mounting side bearing member 1 is sandwiched between a housing mounting side upper bearing member 2 and a housing mounting side lower bearing member 3.

The shaft-mounting-side bearing member 1 has a shaft hole 1a, and an upper conical surface 1 whose upper part on the outer peripheral surface is gradually reduced in diameter upward.
b, and the lower part of the outer peripheral surface is formed on a lower conical surface 1c whose diameter gradually decreases downward. In addition,
In the figure, the lower end of the upper conical surface 1b and the upper end of the lower conical surface 1c coincide with each other, but a cylindrical surface may be provided between them to separate them. The inclination angle between the upper conical surface 1b and the lower conical surface 1c is 45
° is good, but there is no particular limitation.

The upper bearing member 2 on the housing mounting side has an upper conical hole 2a having an upwardly decreasing diameter, and generates minute gas dynamic pressure with the upper conical surface 1b of the bearing member 1 on the shaft mounting side. A gap is secured. The housing-mounting-side lower bearing member 3 has a lower conical hole 3a having a gradually decreasing diameter in a downward direction, and a small gap for generating a gas dynamic pressure is secured between the housing-mounting-side lower bearing member 3 and the lower conical surface 1c of the shaft-mounting-side bearing member 1. Is done.

In this gas dynamic pressure bearing A, a shaft mounting side bearing member 1 is mounted on a fixed side, and a housing mounting side upper bearing member 2 and a housing mounting side lower bearing member 3 rotate (hereinafter, referred to as a shaft fixed type). ) And a type in which the shaft-mounting-side bearing member 1 rotates and the housing-mounting-side upper bearing member 2 and the housing-mounting-side lower bearing member 3 are mounted on the fixed side (hereinafter, referred to as a housing fixed type). The direction of the dynamic pressure generating groove is reversed depending on the direction.

If the gas dynamic pressure bearing A is of a fixed shaft type, it moves when the upper bearing member 2 on the housing mounting side and the lower bearing member 3 on the housing mounting side are rotated in the direction of arrow a shown in FIG. In order to generate pressure, the bearing members 1, 2, 3 are provided with a dynamic pressure generating groove p at any one of the combinations shown in FIG. 2 (a), (b), (c) or (d). FIG.
2 (a) is a view in which a dynamic pressure generating groove p is provided in an upper conical surface 1b and a lower conical surface 1c of the bearing member 1. FIG. 2 (b) shows an upper conical hole 2a of the bearing member 2 and a lower conical hole 3a of the bearing member 3. 2 (c) shows the upper conical surface 1b of the bearing member 1. FIG.
2 (d), a dynamic pressure generating groove p is provided in the lower conical surface 1c of the bearing member 1 and an upper conical hole 2a of the bearing member 2. FIG. Shows where they can be.

When the gas dynamic pressure bearing A is a fixed housing type, the "-"-shaped bending of the dynamic pressure generating groove p is reversed. Note that the dynamic pressure generating groove p is not limited to the herringbone groove having a “<” shape.

When the upper bearing member 2 on the housing mounting side and the lower bearing member 3 on the housing mounting side rotate as indicated by an arrow a, air is taken into the dynamic pressure generating groove p by utilizing the viscosity of air, and the pressure is increased to mount the shaft. As the side bearing member 1, the housing mounting side upper bearing member 2 and the housing mounting side lower bearing member 3 are in a floating state with a small gap secured. Since the bearing members 1, 2, and 3 are provided with a conical surface that reduces the diameter of the dynamic pressure generating groove upward and a conical surface that decreases the diameter downward, the radial dynamic pressure bearing function and the thrust dynamic pressure bearing function are provided. You can have both.

The bearing members 1, 2, 3 are made of a low-cost metal material in which a dynamic pressure generating groove is easily formed. The upper conical surface 1b and the lower conical surface 1c of the shaft mounting side bearing member 1, the upper conical hole 2a of the housing mounting side lower bearing member 2, and the lower conical hole 3a of the housing mounting side lower bearing member 3 An ultra-wear-resistant coating such as like carbon is formed to prevent wear and extend the life of the bearing.

When the gas dynamic pressure bearing A is of a fixed shaft type, the upper conical surface 1b of the shaft mounting side bearing member 1 is attached to the upper portion of the housing mounting side at the time of operation start and operation stop where the dynamic pressure is insufficiently generated. Since the upper conical hole 2a of the bearing member 2 slides and rotates and wears, a super wear-resistant film such as diamond-like carbon is formed on at least the upper conical surface 1b and the upper conical hole 2a, thereby preventing wear and ensuring a long life of the bearing. It should be done.

When the gas dynamic pressure bearing A is of a housing fixed type, the lower conical surface 1c of the shaft mounting side bearing member 1 at the time of starting operation and at the time of stopping operation where the dynamic pressure is insufficiently generated.
And the lower conical hole 3a of the lower bearing member 3 on the housing mounting side
At least the lower conical surface 1c
It is sufficient that a super wear-resistant coating such as diamond-like carbon is formed on the lower conical hole 3a to prevent wear and extend the life of the bearing.

In particular, the upper bearing member 2 on the housing mounting side
The formation of an ultra-wear-resistant coating such as diamond-like carbon on the upper conical hole 2a of the cylindrical member and the lower conical hole 3a of the lower bearing member 3 on the housing mounting side is easy, unlike the formation of the coating on the inner peripheral surface of the cylinder. Can be done.

FIG. 3 is a sectional view of a spindle motor employing a gas dynamic pressure bearing according to the first embodiment of the second invention. In the spindle motor SM, a fixed shaft 5 is integrally provided upright at the center of a disk-shaped fixed portion 4 for mounting the entire motor, and a cap-shaped housing (rotor) 6 for housing the motor portion is covered. . The lower end of the housing 6 is provided with a flange 6a.

A stator 7 is fitted and fixed to a lower portion of the fixed shaft 5, and an electromagnetic coil 8 is wound around a slot. The electromagnetic coil 8 is connected to the electromagnetic coil 8 through a feed line 9 passed through a hole 5 a formed in the fixed shaft 5. Power is supplied, and a cylindrical permanent magnet 10 fitted and fixed to the inner surface of the housing 6 surrounds the outer periphery of the stator 7.

In particular, in this embodiment, the gas dynamic pressure bearing according to the first invention of the present application is provided above the motor section. In this gas dynamic pressure bearing A, the shaft mounting side bearing member 1 is fitted and fixed to the fixed shaft 5, and the housing mounting side upper bearing member 2 and the housing mounting side lower bearing member 3 are provided on the inner peripheral surface of the housing 6. It is a fixed shaft fixed type. Since the bearing members 1, 2, and 3 are provided with a conical surface that reduces the diameter of the dynamic pressure generating groove upward and a conical surface that decreases the diameter downward, the radial dynamic pressure bearing function and the thrust dynamic pressure bearing function are provided. Have both.

FIG. 4 is a sectional view of a spindle motor employing a gas dynamic pressure bearing according to a second embodiment of the present invention. Spindle motor SM of this embodiment
The gas dynamic pressure bearing A according to the first invention of the present application is provided below the motor unit. The other configurations are the same as those in FIG. 3, and thus the same reference numerals as in FIG.

FIG. 5 is a sectional view of a spindle motor employing a gas dynamic pressure bearing according to a third embodiment of the second invention of the present application. In the spindle motor SM, a rotating shaft 11 is passed through the center of a cap-shaped housing 6 for mounting the entire motor, a cylindrical permanent magnet 10 is fitted and fixed below the rotating shaft 11, and a stator is mounted on the inner surface of the housing 6. 7 is fitted and fixed, and the electromagnetic coil 8 is wound around the slot. In the gas dynamic pressure bearing A, the shaft mounting side bearing member 1 is fixedly fitted to the rotating shaft 11, and the housing mounting side upper bearing member 2 and the housing mounting side lower bearing member 3 are fixed to the inner peripheral surface of the housing 6. Housing fixed type.

FIG. 6 is a sectional view of a spindle motor employing a gas dynamic pressure bearing according to a fourth embodiment of the second invention of the present application. Spindle motor SM of this embodiment
The gas dynamic pressure bearing A according to the first invention of the present application is provided below the motor unit. The other configuration is the same as that of FIG. 5, and therefore, the same reference numerals as in FIG.

FIG. 7 shows a rotary device employing a spindle motor according to the first embodiment of the third invention of the present application. This rotator device has a configuration in which a polygon mirror 12 is fitted and fixed to a housing 6 of a spindle motor SM shown in FIG. 3, and a fixing portion 1 is fixed to a bottom surface of a mirror case 13. FIG. 8 shows a rotary device employing a spindle motor according to a second embodiment of the third invention of the present application. This rotator device is a disk device, and is formed by attaching a rotating disk 14 such as a magnetic disk or an optical disk to a housing 6 of a spindle motor SM shown in FIG.

[0025]

As described above, according to the gas dynamic pressure bearing of the first invention of the present application and the spindle motor employing the gas dynamic pressure bearing of the second invention of the present application, the shaft and the bearing surface face upward. Combination of conical pair of conical surfaces to reduce diameter and conical pair of conical surfaces to reduce diameter downwards has both the function of radial bearing and the function of thrust bearing, and it is easy to form super wear-resistant coating such as diamond-like carbon. Because of its shape, it is possible to select a low-cost metal material that easily forms a dynamic pressure generating groove in the bearing material, and has a bearing life equivalent to that of a super-hard material such as ceramic.

According to the rotary device employing the spindle motor of the third invention of the present application, the above-mentioned effects of the gas dynamic pressure bearing and the spindle motor are obtained, and the quality and reliability of the rotary device are improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a gas dynamic pressure bearing according to a first embodiment of the first invention of the present application.

FIG. 2 is a dynamic pressure generating groove provided in a gas radial bearing of a spindle motor.

FIG. 3 is a longitudinal sectional view of a spindle motor according to the first embodiment of the second invention of the present application.

FIG. 4 is a longitudinal sectional view of a spindle motor according to a second embodiment of the second invention of the present application.

FIG. 5 is a longitudinal sectional view of a spindle motor according to a third embodiment of the second invention of the present application.

FIG. 6 is a longitudinal sectional view of a spindle motor according to a fourth embodiment of the present invention.

FIG. 7 is a rotating body device employing the spindle motor according to the first embodiment of the third invention of the present application.

FIG. 8 shows a rotating body device employing a spindle motor according to a second embodiment of the third invention of the present application.

[Explanation of symbols]

 A Gas dynamic pressure bearing 1 Shaft mounting side bearing member 1b Upper conical surface 1c Lower conical surface 2 Housing mounting side upper bearing member 2a Upper conical hole 3 Housing mounting side lower bearing member 3a Lower conical hole p Dynamic pressure generating groove 5 Fixed shaft SM Spindle motor 6 Housing 7 Stator 8 Electromagnetic coil 10 Permanent magnet 11 Rotary axis 12 Polygon mirror 14 Rotated disk

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[Procedure amendment]

[Submission date] April 8, 1998

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction contents]

According to the present invention, the shaft and the bearing surface are shaped so as to easily form a super wear-resistant coating such as diamond-like carbon.
Dynamic pressure bearings , spindle motors employing dynamic pressure bearings ,
And a rotating body device employing a spindle motor.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Change

[Correction contents]

[0005]

According to a first aspect of the present invention, there is provided a shaft-mounting-side bearing member whose upper and lower ends are conically reduced in diameter, and an upper conical hole having an upwardly decreasing diameter. A housing-mounting-side upper bearing member installed such that a conical hole is close to an upper conical surface of the shaft-mounting-side bearing member;
A lower conical hole having a gradually decreasing diameter in a downward direction, the lower conical hole being provided on a housing mounting side lower bearing member installed so as to be close to a lower conical surface of the shaft mounting side bearing member; A dynamic pressure generating groove is provided on one of the upper conical surface of the side bearing member and the upper bearing member on the housing mounting side, and the lower conical surface of the shaft mounting side bearing member and the lower conical surface of the housing mounting side are provided. The present invention provides a dynamic pressure bearing characterized in that a dynamic pressure generating groove is provided in any one of them. This dynamic pressure shaft
In the bearing, the shaft mounting side bearing member has the upper part
Providing a cylindrical surface connected to the conical surface and the lower conical surface;
In the upper bearing member on the mounting side, the upper conical hole
An upper cylindrical hole that is connected and faces the cylindrical surface;
The lower bearing member on the housing mounting side has the lower cone
A lower cylindrical hole connected to the hole and facing the cylindrical surface is provided.
May be configured. Also, in this dynamic pressure bearing,
Upper and lower conical surfaces of the shaft mounting side bearing member, and
An upper conical hole of the upper bearing member on the housing mounting side;
And the lower conical hole of the lower bearing member on the housing mounting side
Diamond like carbon (DLC)
May be implemented. The second invention of the present application is the shaft mounting side bearing member of the first invention fixed to the rotating shaft, and the housing mounting side upper bearing member and the housing mounting side lower bearing member are fixed to the fixing portion , Or shaft mounting
The bearing member is fixed to the fixed part,
Upper bearing member on jing mounting side and lower side on housing mounting side
Wherein the outer bearing member is fixed to the rotating shaft
An object of the present invention is to provide a spindle motor using a dynamic pressure bearing .

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction contents]

According to a third aspect of the present invention, there is provided a rotating body employing a spindle motor, wherein a rotating body such as a polygon mirror or a magnetic disk or an optical disk is mounted on a rotating shaft of the spindle motor according to the second aspect of the invention. An apparatus is provided.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction contents]

When the housing-mounting-side upper bearing member 2 and the housing-mounting-side lower bearing member 3 rotate as indicated by an arrow a, air is trapped in the dynamic pressure generating groove p due to the viscosity of the air.
Filled-in increased pressure, against the shaft mounting side bearing member 1
Thus, the housing-mounting-side upper bearing member 2 and the housing-mounting-side lower bearing member 3 are floated with a small gap secured. Since the bearing members 1, 2, and 3 are provided with a conical surface that reduces the diameter of the dynamic pressure generating groove upward and a conical surface that decreases the diameter downward, the radial dynamic pressure bearing function and the thrust dynamic pressure bearing function are provided. You can have both.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0024

[Correction method] Change

[Correction contents]

FIG. 7 shows a rotary device employing a spindle motor according to the first embodiment of the third invention of the present application. The rotator apparatus, the polygon mirror 12 to the housing 6 of the spindle motor SM in Figure 3 are fixed fitted on a solid
In this configuration, the fixed base 4 is fixed to the bottom of the mirror case 13. FIG. 8 shows a rotary device employing a spindle motor according to a second embodiment of the third invention of the present application. This rotator device is a disk device, and is formed by attaching a rotating disk 14 such as a magnetic disk or an optical disk to a housing 6 of a spindle motor SM shown in FIG.

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0025

[Correction method] Change

[Correction contents]

[0025]

As described above, according to the dynamic pressure bearing of the first invention of the present application and the spindle motor employing the dynamic pressure bearing of the second invention of the present application, the shaft and the bearing surface are reduced in diameter upward. It has a combination of a conical pair of conical surfaces and a conical pair of conical surfaces that contracts downward, so that it has both the function of a radial bearing and the function of a thrust bearing, and has a shape that can easily form an ultra-wear-resistant coating such as diamond-like carbon. Therefore, a low-cost metal material that can easily form a dynamic pressure generation groove in the bearing material can be selected, and has a bearing life equivalent to that of a super-hard material such as ceramic.

[Procedure amendment 8]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Change

[Correction contents]

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a gas dynamic pressure bearing according to a first embodiment of the first invention of the present application.

FIG. 2 is a gas according to the first embodiment of the first invention of the present application .
FIG. 4 is an explanatory view of a dynamic pressure generating groove provided on a bearing surface of the dynamic pressure bearing.
You.

FIG. 3 is a longitudinal sectional view of a spindle motor according to the first embodiment of the second invention of the present application.

FIG. 4 is a longitudinal sectional view of a spindle motor according to a second embodiment of the second invention of the present application.

FIG. 5 is a longitudinal sectional view of a spindle motor according to a third embodiment of the second invention of the present application.

FIG. 6 is a longitudinal sectional view of a spindle motor according to a fourth embodiment of the present invention.

FIG. 7 is a longitudinal sectional view of a rotating device employing a spindle motor according to the first embodiment of the third invention of the present application.

FIG. 8 is an external view of a rotating body device employing a spindle motor according to a second embodiment of the third invention of the present application.

Claims (3)

[Claims] 1. A bearing member having a shaft mounting side whose upper and lower ends are conically reduced in diameter, and an upper conical hole having an upwardly decreasing diameter, the upper conical hole being formed in an upper portion of the shaft mounting side bearing member. An upper bearing member on the housing mounting side installed close to the conical surface, and a lower conical hole having a gradually decreasing downward diameter, the lower conical hole being close to the lower conical surface of the bearing member on the shaft mounting side. A lower bearing member on the housing mounting side installed as described above, and a dynamic pressure generation groove is provided on one of the upper conical surface of the bearing member on the shaft mounting side and the upper bearing member on the housing mounting side,
A dynamic pressure bearing, wherein a dynamic pressure generating groove is provided on one of the lower conical surface of the shaft mounting side bearing member and the housing mounting side lower bearing member. 2. The shaft mounting side bearing member according to claim 1 is fixed to a shaft, and the housing mounting side upper bearing member and the housing mounting side lower bearing member are fixed to the housing. Spindle motor with dynamic pressure bearing. 3. A rotary device comprising a spindle motor according to claim 2, wherein a rotary member such as a polygon mirror or a magnetic disk or an optical disk is attached to a spindle of the spindle motor.