JP2007056978A - Magnetic fluid bearing - Google Patents

Magnetic fluid bearing Download PDF

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Publication number
JP2007056978A
JP2007056978A JP2005242507A JP2005242507A JP2007056978A JP 2007056978 A JP2007056978 A JP 2007056978A JP 2005242507 A JP2005242507 A JP 2005242507A JP 2005242507 A JP2005242507 A JP 2005242507A JP 2007056978 A JP2007056978 A JP 2007056978A
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Japan
Prior art keywords
bearing
magnetic fluid
magnetic
outer ring
shaft
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JP2005242507A
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Japanese (ja)
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Tsuguto Nakaseki
嗣人 中関
Ken Yamamoto
山本　　憲
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NTN Corp
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NTN Corp
NTN Toyo Bearing Co Ltd
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Priority to JP2005242507A priority Critical patent/JP2007056978A/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C32/00—Bearings not otherwise provided for
    • F16C32/04—Bearings not otherwise provided for using magnetic or electric supporting means
    • F16C32/0406—Magnetic bearings
    • F16C32/0408—Passive magnetic bearings
    • F16C32/0423—Passive magnetic bearings with permanent magnets on both parts repelling each other
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C2370/00—Apparatus relating to physics, e.g. instruments
    • F16C2370/12—Hard disk drives or the like
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
    • F16C33/02—Parts of sliding-contact bearings
    • F16C33/04—Brasses; Bushes; Linings
    • F16C33/06—Sliding surface mainly made of metal
    • F16C33/10—Construction relative to lubrication
    • F16C33/1025—Construction relative to lubrication with liquid, e.g. oil, as lubricant
    • F16C33/103—Construction relative to lubrication with liquid, e.g. oil, as lubricant retained in or near the bearing
    • F16C33/1035—Construction relative to lubrication with liquid, e.g. oil, as lubricant retained in or near the bearing by a magnetic field acting on a magnetic liquid

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Magnetic Bearings And Hydrostatic Bearings (AREA)
  • Moving Of Heads (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic fluid bearing for supporting a radial load as well as an axial load with low friction. <P>SOLUTION: The magnetic fluid bearing 1 comprises a plurality of magnetic poles 4 provided on the whole periphery of a bearing gap-forming face 7a of either one of a bearing outer ring 2 and a shaft 3 fitted in the bearing outer ring 2 via a bearing gap (g) in the state of being mutually decentralized in the circumferential direction. The other of the bearing outer ring 2 and the shaft 3 is formed of a non-magnetic material, and magnetic fluid 5 is held in the bearing gap (g) by the plurality of magnetic poles 4. Magnets 11 are arranged at both ends of the bearing, and a magnet 13 is provided on the end face of the non-magnetic material so that its face has the same polarity as opposite one of each magnet 11. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

この発明は、磁性流体によって軸を支持する磁性流体軸受に関する。   The present invention relates to a magnetic fluid bearing that supports a shaft by a magnetic fluid.

この種の磁性流体軸受の基本構造は、軸受外輪と、この軸受外輪内に軸受隙間を介して嵌められた軸のいずれか一方の部材の軸受隙間形成面に、複数の磁極を互いに円周方向に分離して全周に設け、他方の部材を非磁性材料とし、上記複数の磁極により軸受隙間内に磁性流体を保持させたものである（例えば特許文献１）。
特開２００４−２１８７９２号公報 The basic structure of this type of ferrofluid bearing is that a plurality of magnetic poles are arranged in the circumferential direction on the bearing clearance forming surface of either a bearing outer ring or a shaft fitted in the bearing outer ring via a bearing clearance. And the other member is made of a non-magnetic material, and the magnetic fluid is held in the bearing gap by the plurality of magnetic poles (for example, Patent Document 1).
JP 2004-218792 A

しかし、上記構造の磁性流体軸受では、軸受面が円筒形状であるため、アキシャル方向の荷重を受けることができない。   However, the magnetic fluid bearing having the above structure cannot receive a load in the axial direction because the bearing surface has a cylindrical shape.

この発明の目的は、ラジアル方向の荷重だけでなくアキシャル方向の荷重も低摩擦で支持できる磁性流体軸受を提供することである。   An object of the present invention is to provide a magnetic fluid bearing capable of supporting not only a radial load but also an axial load with low friction.

この発明の磁性流体軸受は、軸受外輪とこの軸受外輪内に軸受隙間を介して嵌まった軸のいずれか一方の軸受隙間形成面に、複数の磁極を互いに円周方向に並べて全周に設け、前記軸受外輪と軸との他方は非磁性材料からなり、上記複数の磁極により上記軸受隙間内に磁性流体を保持させてなるラジアル軸受部を有する磁性流体軸受において、前記ラジアル軸受部を軸方向に挟む両側の位置に、互いに同極の面が軸方向に対向する一対の磁石の組からなるアキシャル軸受部を配置し、これらアキシャル軸受部の対向する片方の磁石を前記軸受外輪に、もう片方の磁石を前記軸それぞれ設けたことを特徴とする。上記円周方向に並ぶ複数の磁極は、例えば円周方向に分散して設けられたものとする。   The magnetic fluid bearing of the present invention has a plurality of magnetic poles arranged in the circumferential direction on the entire circumference of the bearing gap forming surface of either the bearing outer ring or the shaft fitted in the bearing outer ring via the bearing gap. The other of the bearing outer ring and the shaft is made of a non-magnetic material, and has a radial bearing portion in which the magnetic fluid is held in the bearing gap by the plurality of magnetic poles. Axial bearings consisting of a pair of magnets with the same pole surfaces facing each other in the axial direction are disposed at both sides sandwiched between the two bearings, and one of the opposing magnets of the axial bearing is placed on the bearing outer ring. The magnet is provided for each of the shafts. The plurality of magnetic poles arranged in the circumferential direction are provided dispersed in the circumferential direction, for example.

この構成によると、ラジアル軸受部において、軸受隙間内の磁性流体は円周方向に並んで複数設けられた個々の磁極で保持される。そのため、軸受外輪と軸との間に外部からラジアル方向の荷重が作用して軸受隙間が円周の一部で小さくなろうとしても、磁極により保持された磁性流体は移動することがなく、軸受隙間は潤滑性のある磁性流体で一定の大きさに保持される。また、アキシャル軸受部では、軸受の両端において軸受外輪と軸とに分けて互いに対向させて設けた磁石の対向する面を同極としているので、対向する磁石の間で働く反発力により、軸受外輪と軸との間に外部から働くスラスト方向の荷重が支持される。これにより、ラジアル方向の荷重だけでなくアキシャル方向の荷重も低摩擦で支持することができる。   According to this configuration, in the radial bearing portion, the magnetic fluid in the bearing gap is held by a plurality of individual magnetic poles provided side by side in the circumferential direction. Therefore, even if a radial load is applied from the outside between the bearing outer ring and the shaft to reduce the bearing gap at a part of the circumference, the magnetic fluid held by the magnetic pole does not move, and the bearing The gap is maintained at a certain size by a magnetic fluid having lubricity. Further, in the axial bearing portion, the opposing surfaces of the magnets provided to be opposed to each other in the bearing outer ring and the shaft are made the same polarity at both ends of the bearing, so that the bearing outer ring is caused by the repulsive force acting between the facing magnets. A thrust load acting from the outside is supported between the shaft and the shaft. As a result, not only the radial load but also the axial load can be supported with low friction.

この発明において、前記ラジアル軸受部の軸受隙間形成面に、前記磁性流体を溜める磁性流体溜まり溝を設けても良い。磁性流体溜まり溝が設けられていると、長期にわたり軸受隙間内に磁性流体を介在させることができ、信頼性の高い磁性流体軸受とすることができる。   In the present invention, a magnetic fluid reservoir groove for storing the magnetic fluid may be provided on a bearing clearance forming surface of the radial bearing portion. When the magnetic fluid reservoir groove is provided, the magnetic fluid can be interposed in the bearing gap over a long period of time, and a highly reliable magnetic fluid bearing can be obtained.

この発明の磁性流体軸受は、ハードディスクドライブ装置のスイングアームを支持する支点軸受として用いられるものであっても良い。
この磁性流体軸受は、ラジアル方向に磁性流体を介して支持され、かつアキシャル方向の力は、磁石の反発する力を利用し、非接触で支持されることから、ハードディスクドライブ装置のスイングアームの支点軸受として用いた場合、低摩擦で揺動抵抗が小さく、高い減衰性能を持つことができ、迅速に高精度に位置決めが行える。 The magnetic fluid bearing of the present invention may be used as a fulcrum bearing that supports a swing arm of a hard disk drive device.
This magnetic fluid bearing is supported through a magnetic fluid in the radial direction, and the axial force is supported in a non-contact manner using the repulsive force of the magnet, so that the fulcrum of the swing arm of the hard disk drive device When used as a bearing, low friction, low rocking resistance, high damping performance, and quick and accurate positioning.

この発明の磁性流体軸受は、軸受外輪とこの軸受外輪内に軸受隙間を介して嵌まった軸のいずれか一方の軸受隙間形成面に、複数の磁極を互いに円周方向に並べて全周に設け、前記軸受外輪と軸との他方は非磁性材料からなり、上記複数の磁極により上記軸受隙間内に磁性流体を保持させてなるラジアル軸受部を有する磁性流体軸受において、前記ラジアル軸受部を軸方向に挟む両側の位置に、互いに同極の面が軸方向に対向する一対の磁石の組からなるアキシャル軸受部を配置し、これらアキシャル軸受部の対向する片方の磁石を前記軸受外輪に、もう片方の磁石を前記軸それぞれ設けたため、ラジアル方向の荷重だけでなくアキシャル方向の荷重も低摩擦で支持することができる。   The magnetic fluid bearing of the present invention has a plurality of magnetic poles arranged in the circumferential direction on the entire circumference of the bearing gap forming surface of either the bearing outer ring or the shaft fitted in the bearing outer ring via the bearing gap. The other of the bearing outer ring and the shaft is made of a non-magnetic material, and has a radial bearing portion in which the magnetic fluid is held in the bearing gap by the plurality of magnetic poles. Axial bearings consisting of a pair of magnets with the same pole surfaces facing each other in the axial direction are disposed at both sides sandwiched between the two bearings, and one of the opposing magnets of the axial bearing is placed on the bearing outer ring. Since each of the shafts is provided, not only the radial load but also the axial load can be supported with low friction.

この発明の第１の実施形態を図１および図２と共に説明する。この磁性流体軸受１は、ハードディスクドライブ装置（以下「ＨＤＤ装置」と称す）のスイングアーム用支点軸受として用いられるものである。この磁性流体軸受１は、図１（Ａ）に縦断面図で示すように、円筒状の軸受外輪２と、この軸受外輪２内に軸受隙間ｇ（図１（Ｂ））を介して嵌まった軸３と、前記軸受隙間ｇに入れられた磁性流体５とを備え、軸受外輪２と軸３とは相対回転自在とされる。軸受外輪２は非磁性材料からなる。軸３は、非磁性材料からなる中空軸体６と、この中空軸体６の外径面に巻回固定した永久磁石材料７とを有する。この永久磁石材料７の外周面と、前記軸受外輪２の内周面とが、前記軸受隙間ｇの形成面７ａ，２ａとなる。磁性流体５には潤滑性のあるものが用いられる。   A first embodiment of the present invention will be described with reference to FIGS. The magnetic fluid bearing 1 is used as a fulcrum bearing for a swing arm of a hard disk drive device (hereinafter referred to as “HDD device”). The magnetic fluid bearing 1 is fitted into a cylindrical bearing outer ring 2 and a bearing gap g (FIG. 1B) in the bearing outer ring 2 as shown in a longitudinal sectional view in FIG. The shaft 3 and the magnetic fluid 5 placed in the bearing gap g are provided so that the bearing outer ring 2 and the shaft 3 are relatively rotatable. The bearing outer ring 2 is made of a nonmagnetic material. The shaft 3 includes a hollow shaft body 6 made of a nonmagnetic material and a permanent magnet material 7 wound around and fixed to the outer diameter surface of the hollow shaft body 6. The outer peripheral surface of the permanent magnet material 7 and the inner peripheral surface of the bearing outer ring 2 become the formation surfaces 7a and 2a of the bearing gap g. As the magnetic fluid 5, a fluid having lubricity is used.

図１（Ａ）のII−II矢視断面図を示す図２のように、永久磁石材料７側の軸受隙間形成面７ａには複数の磁極４が円周方向に並んで設けられ、これらの磁極４により軸受隙間ｇ内に磁性流体５が保持される。これら複数の磁極４は、互いに円周方向および軸方向の両方に分離されたものであり、隣り合う磁極４は互いに極性が異なるようにされている。これら複数の磁極４は、互いに接するように配置されていても良い。これら各磁極４は、永久磁石材料７の外周面に着磁を施すことにより設けられる。永久磁石材料７としては、加工性や取扱性の観点から、着磁のときの印加磁界が小さくてよい半硬質磁鋼が好ましい。前記軸受外輪２の軸受隙間形成面２ａと、軸３側の永久磁石材料７の軸受隙間形成面７ａと、その軸受隙間形成面７ａに設けられる複数の磁極４と、両軸受隙間形成面２ａ，７ａで形成される軸受隙間ｇ内に保持される磁性流体５とで、この磁性流体軸受１のラジアル軸受部１ａが構成される。   As shown in FIG. 2 showing a cross-sectional view taken along the line II-II in FIG. 1 (A), a plurality of magnetic poles 4 are arranged in the circumferential direction on the bearing gap forming surface 7a on the permanent magnet material 7 side. The magnetic fluid 5 is held in the bearing gap g by the magnetic pole 4. The plurality of magnetic poles 4 are separated from each other in both the circumferential direction and the axial direction, and the adjacent magnetic poles 4 have different polarities. The plurality of magnetic poles 4 may be arranged in contact with each other. Each of these magnetic poles 4 is provided by magnetizing the outer peripheral surface of the permanent magnet material 7. The permanent magnet material 7 is preferably a semi-hard magnetic steel that requires a small applied magnetic field when magnetized, from the viewpoint of workability and handleability. The bearing gap forming surface 2a of the bearing outer ring 2, the bearing gap forming surface 7a of the permanent magnet material 7 on the shaft 3, the plurality of magnetic poles 4 provided on the bearing gap forming surface 7a, and both bearing gap forming surfaces 2a, A radial bearing portion 1a of the magnetic fluid bearing 1 is constituted by the magnetic fluid 5 held in the bearing gap g formed by 7a.

軸受外輪２の両端には、その内周面側において軸方向に凹陥した段面２ｂがそれぞれ全周にわたって形成され、これら各段面２ｂにその周方向に沿ってリング状の磁石１１が設けられている。これらリング状の磁石１１は、それぞれ磁極１２が軸方向に向くものである。他方、軸３の両端には、軸受外輪２の両端の前記各磁石１１と軸方向に対向し、かつ軸方向に磁極１４を向けたリング状の磁石１３がそれぞれ設けられている。図１（Ａ）のＡ部を拡大して示す図１（Ｂ）のように、互いに対向する前記磁石１１，１３の対向面の磁極１２，１４は同極となるように設定される。   At both ends of the bearing outer ring 2, stepped surfaces 2b that are recessed in the axial direction on the inner peripheral surface side are formed over the entire circumference, and ring-shaped magnets 11 are provided on the respective stepped surfaces 2b along the circumferential direction. ing. Each of the ring-shaped magnets 11 has a magnetic pole 12 facing in the axial direction. On the other hand, ring-shaped magnets 13 are provided at both ends of the shaft 3 so as to face the magnets 11 at both ends of the bearing outer ring 2 in the axial direction and have the magnetic poles 14 directed in the axial direction. As shown in FIG. 1B, which is an enlarged view of portion A in FIG. 1A, the magnetic poles 12 and 14 on the facing surfaces of the magnets 11 and 13 facing each other are set to have the same polarity.

具体的には、軸３における中空軸体６の上端部外周面には、永久磁石材料７の上端に続き前記軸受外輪２の段面２ｂに対向するフランジ部８ａを有するリング状の磁石支持部材８が固定されている。この磁石支持部材８は非磁性材料からなり、そのフランジ部８ａの前記軸受外輪２側の磁石１１に対向する面に、軸３側の磁石１３が設けられる。   Specifically, a ring-shaped magnet support member having a flange portion 8 a facing the step surface 2 b of the bearing outer ring 2 on the outer peripheral surface of the upper end portion of the hollow shaft body 6 in the shaft 3 following the upper end of the permanent magnet material 7. 8 is fixed. The magnet support member 8 is made of a non-magnetic material, and a magnet 13 on the shaft 3 side is provided on the surface of the flange portion 8a facing the magnet 11 on the bearing outer ring 2 side.

軸３における中空軸体６は内径面に雌ねじ６ａを有し、その下端部には外周面側において軸方向に凹陥した段面６ｂが全周にわたって形成され、この段面６ｂに軸３を支持する基台２３のリング状着座部２３ａが嵌合する。このリング状着座部２３ａは、基台２３の裏面から中空軸体６の雌ねじ６ａに螺合させた止めねじ２７で締め付けることにより、中空軸体６に固定される。前記リング状着座部２３ａの上端面に軸３の下端側の磁石１３が設けられる。
軸受外輪２側の磁石１１と、この磁石１１と軸方向に対向する軸３側の磁石１３とで、この磁性流体軸受１のスラスト軸受部１ｂが構成される。 The hollow shaft 6 in the shaft 3 has a female thread 6a on the inner diameter surface, and a step surface 6b that is recessed in the axial direction on the outer peripheral surface side is formed on the entire outer periphery, and the shaft 3 is supported by the step surface 6b. The ring-shaped seat part 23a of the base 23 to be fitted is fitted. The ring-shaped seat portion 23 a is fixed to the hollow shaft body 6 by tightening with a set screw 27 screwed into the female screw 6 a of the hollow shaft body 6 from the back surface of the base 23. A magnet 13 on the lower end side of the shaft 3 is provided on the upper end surface of the ring-shaped seat portion 23a.
The magnet 11 on the bearing outer ring 2 side and the magnet 13 on the shaft 3 side facing the magnet 11 in the axial direction constitute a thrust bearing portion 1b of the magnetic fluid bearing 1.

この構成の磁性流体軸受１によると、そのラジアル軸受部１ａでは、軸３側の軸受隙間形成面７ａの複数の磁極４によって軸受隙間ｇ内に磁性流体５が保持される。軸受外輪２と軸３との間に外部からラジアル方向の荷重が作用して軸受隙間ｇが円周の一部で小さくなろうとしても、磁極４により保持された磁性流体５は移動することがなく、軸受隙間ｇは潤滑性のある磁性流体５の介在により、全周にわたって一定の大きさに保持される。すなわち、軸３は軸受外輪２との相対回転時だけでなく、非回転の状態においても、軸受外輪２と非接触でかつ軸心位置に支持される。
また、アキシャル軸受部１ｂでは、軸受外輪２の両端に設けられる磁石１１と、この磁石１１と軸方向に対向して軸３の両端に設けられ、前記磁石１１の磁極１２と同極の磁極１４が対向する磁石１３とに働く反発力により、軸受外輪２と軸３との間に外部から働くスラスト方向の荷重を支持して、軸受外輪２と軸３を非接触状態に保つことができる。 According to the magnetic fluid bearing 1 having this configuration, in the radial bearing portion 1a, the magnetic fluid 5 is held in the bearing gap g by the plurality of magnetic poles 4 on the bearing gap forming surface 7a on the shaft 3 side. Even if a radial load is applied from the outside between the bearing outer ring 2 and the shaft 3 to reduce the bearing gap g at a part of the circumference, the magnetic fluid 5 held by the magnetic pole 4 can move. Rather, the bearing gap g is maintained at a constant size over the entire circumference by the magnetic fluid 5 having lubricity. That is, the shaft 3 is supported at the axial center position without contact with the bearing outer ring 2 not only in the relative rotation with the bearing outer ring 2 but also in the non-rotating state.
Further, in the axial bearing portion 1b, magnets 11 provided at both ends of the bearing outer ring 2 and poles 14 having the same polarity as the magnetic pole 12 of the magnet 11 are provided at both ends of the shaft 3 so as to face the magnet 11 in the axial direction. A thrust force acting from the outside is supported between the bearing outer ring 2 and the shaft 3 by the repulsive force acting on the opposing magnet 13, and the bearing outer ring 2 and the shaft 3 can be kept in a non-contact state.

このように、磁性流体軸受１は、ラジアル方向に磁性流体５を介して支持され、かつアキシャル方向の力は、磁石１１，１３の反発する力を利用し、非接触で支持されることから、ラジアル方向およびアキシャル方向共に、低摩擦で支持することができる。また、ラジアル方向およびアキシャル方向共に、非回転の状態においても非接触で支持することができる。   Thus, the magnetic fluid bearing 1 is supported in the radial direction via the magnetic fluid 5, and the axial force is supported in a non-contact manner using the repulsive force of the magnets 11 and 13. Both radial and axial directions can be supported with low friction. Further, both the radial direction and the axial direction can be supported without contact even in a non-rotating state.

なお、この実施形態では、ラジアル軸受部１ａにおいて、軸３側の軸受隙間形成面７ａに磁極４を設けたが、軸受外輪２側の軸受隙間形成面２ａに磁極４を設けても良い。またこの実施形態では、軸受隙間形成面７ａに着磁することで磁極４を設けたが、軸受隙間形成面に磁石を埋め込むことで磁極４を設けても良い。   In this embodiment, the magnetic pole 4 is provided on the bearing gap forming surface 7a on the shaft 3 side in the radial bearing portion 1a. However, the magnetic pole 4 may be provided on the bearing gap forming surface 2a on the bearing outer ring 2 side. In this embodiment, the magnetic pole 4 is provided by magnetizing the bearing gap forming surface 7a. However, the magnetic pole 4 may be provided by embedding a magnet in the bearing gap forming surface.

図３は、上記構成の磁性流体軸受１を支点軸受として使用したＨＤＤ装置におけるスイングアーム装置を示す断面図である。このスイングアーム装置２１は、スイングアーム２２を磁性流体軸受１を介して基台２３に、軸３回りに正逆回転自在に設置してある。スイングアーム２２の一端には、磁気ディスク２５の情報記録面に対向する磁気ヘッド２４を設け、スイングアーム２２を正逆に駆動するヘッド位置決め機構２６を設けている。   FIG. 3 is a cross-sectional view showing a swing arm device in an HDD device using the magnetic fluid bearing 1 having the above configuration as a fulcrum bearing. In this swing arm device 21, a swing arm 22 is installed on a base 23 via a magnetic fluid bearing 1 so as to be rotatable forward and backward about an axis 3. At one end of the swing arm 22, a magnetic head 24 that faces the information recording surface of the magnetic disk 25 is provided, and a head positioning mechanism 26 that drives the swing arm 22 in the forward and reverse directions is provided.

基台２３はＨＤＤ装置のハウジング等からなる。ヘッド位置決め機構２６は、スイングアーム２２の他端に設けたロータ２６ａと、このロータ２６ａに対向して基台２３に設置したステータ２６ｂとで構成される揺動型のモータからなる。この例では、ロータ２６ａにコイルが設けられ、ステータ２６ｂに磁石が用いられている。この逆に、ロータ２６ａを磁石、ステータ２６ｂをコイルとしても良い。   The base 23 includes a housing of the HDD device. The head positioning mechanism 26 is composed of a swing type motor including a rotor 26a provided at the other end of the swing arm 22 and a stator 26b installed on the base 23 so as to face the rotor 26a. In this example, a coil is provided in the rotor 26a, and a magnet is used in the stator 26b. Conversely, the rotor 26a may be a magnet and the stator 26b may be a coil.

この磁性流体軸受１は、ラジアル方向に磁性流体５を介して支持され、かつアキシャル方向の力は、磁石１１，１３の反発する力を利用し、非接触で支持されることから、このようにＨＤＤ装置のスイングアーム２２の支点軸受として用いた場合、低摩擦で揺動抵抗が小さく、高い減衰性能を持つことができ、迅速に高精度に位置決めが行える。   Since the magnetic fluid bearing 1 is supported in the radial direction via the magnetic fluid 5 and the axial force is supported in a non-contact manner by utilizing the repulsive force of the magnets 11 and 13. When used as a fulcrum bearing of the swing arm 22 of the HDD device, the friction resistance is small, the swing resistance is small, the damping performance is high, and the positioning can be performed quickly and with high accuracy.

図４は、この発明の他の実施形態を示す。この磁性流体軸受１Ａは、図１および図２に示した第１の実施形態において、ラジアル軸受部１ａの軸３側の軸受隙間形成面７ａに、周方向に延びる複数の磁性流体溜り溝９を設けたものである。その他の構成は図１および図２に示した第１の実施形態の場合と同じである。
このように、磁性流体溜り溝９を軸受隙間形成面７ａに形成することにより、長期にわたり軸受隙間ｇ内に磁性流体５を介在させることができ、信頼性の高い磁性流体軸受１Ａとすることができる。なお、前記磁性流体溜り溝９は、軸受外輪２側の軸受隙間形成面２ａに形成しても良い。 FIG. 4 shows another embodiment of the present invention. In the first embodiment shown in FIGS. 1 and 2, the magnetic fluid bearing 1A has a plurality of magnetic fluid pool grooves 9 extending in the circumferential direction on the bearing gap forming surface 7a on the shaft 3 side of the radial bearing portion 1a. It is provided. Other configurations are the same as those of the first embodiment shown in FIGS.
Thus, by forming the magnetic fluid pool groove 9 in the bearing gap forming surface 7a, the magnetic fluid 5 can be interposed in the bearing gap g for a long time, and the magnetic fluid bearing 1A having high reliability can be obtained. it can. The magnetic fluid pool groove 9 may be formed in the bearing gap forming surface 2a on the bearing outer ring 2 side.

（Ａ）はこの発明の第１の実施形態にかかる磁性流体軸受の縦断面図、（Ｂ）は（Ａ）におけるＡ部の拡大図である。(A) is a longitudinal cross-sectional view of the magnetic fluid bearing concerning 1st Embodiment of this invention, (B) is an enlarged view of the A section in (A). 図１におけるII−II矢視断面図である。It is II-II arrow sectional drawing in FIG. 同磁性流体軸受を用いたＨＤＤ装置のスイングアーム装置の断面図である。It is sectional drawing of the swing arm apparatus of HDD apparatus using the magnetic fluid bearing. （Ａ）はこの発明の他の実施形態にかかる磁性流体軸受の縦断面図、（Ｂ）は（Ａ）におけるＢ部の拡大図である。(A) is a longitudinal cross-sectional view of the magnetic fluid bearing concerning other embodiment of this invention, (B) is an enlarged view of the B section in (A).

符号の説明Explanation of symbols

１，１Ａ…磁性流体軸受
１ａ…ラジアル軸受部
１ｂ…スラスト軸受部
２…軸受外輪
２ａ…軸受隙間形成面
３…軸
４…磁極
５…磁性流体
７ａ…軸受隙間形成面
９…磁性流体溜り溝
１１，１３…磁石
１２，１４…磁極
ｇ…軸受隙間 DESCRIPTION OF SYMBOLS 1,1A ... Magnetic fluid bearing 1a ... Radial bearing part 1b ... Thrust bearing part 2 ... Bearing outer ring 2a ... Bearing clearance formation surface 3 ... Axis 4 ... Magnetic pole 5 ... Magnetic fluid 7a ... Bearing clearance formation surface 9 ... Magnetic fluid pool groove 11 , 13 ... magnets 12 and 14 ... magnetic pole g ... bearing clearance

Claims (3)

軸受外輪とこの軸受外輪内に軸受隙間を介して嵌まった軸のいずれか一方の軸受隙間形成面に、複数の磁極を互いに円周方向に並べて全周に設け、前記軸受外輪と軸との他方は非磁性材料からなり、上記複数の磁極により上記軸受隙間内に磁性流体を保持させてなるラジアル軸受部を有する磁性流体軸受において、前記ラジアル軸受部を軸方向に挟む両側の位置に、互いに同極の面が軸方向に対向する一対の磁石の組からなるアキシャル軸受部を配置し、これらアキシャル軸受部の対向する片方の磁石を前記軸受外輪に、もう片方の磁石を前記軸にそれぞれ設けたことを特徴とする磁性流体軸受。   A plurality of magnetic poles are arranged in the circumferential direction on the bearing clearance forming surface of either one of the bearing outer ring and the shaft fitted in the bearing outer ring via a bearing clearance, and arranged between the bearing outer ring and the shaft. The other is made of a non-magnetic material, and in the magnetic fluid bearing having a radial bearing portion in which the magnetic fluid is held in the bearing gap by the plurality of magnetic poles, the radial bearing portions are positioned at both sides sandwiching the radial bearing portion in the axial direction. Axial bearings consisting of a pair of magnets with the same pole faces facing each other in the axial direction are arranged, one magnet facing each other of these axial bearings is provided on the bearing outer ring, and the other magnet is provided on the shaft. A magnetic fluid bearing characterized by that. 請求項１に記載の磁性流体軸受において、前記ラジアル軸受部の軸受隙間形成面に、前記磁性流体を溜める磁性流体溜まり溝を設けた磁性流体軸受。   The magnetic fluid bearing according to claim 1, wherein a magnetic fluid reservoir groove for storing the magnetic fluid is provided on a bearing clearance forming surface of the radial bearing portion. 請求項１または請求項２記載の磁性流体軸受において、ハードディスクドライブ装置のスイングアームを支持する支点軸受として用いられるものである磁性流体軸受。   3. A magnetic fluid bearing according to claim 1, wherein the magnetic fluid bearing is used as a fulcrum bearing for supporting a swing arm of a hard disk drive device.
JP2005242507A 2005-08-24 2005-08-24 Magnetic fluid bearing Pending JP2007056978A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105864290A (en) * 2015-01-21 2016-08-17 雷虹桥 Electromagnetic speed control high-speed dual-layer nested bearing

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105864290A (en) * 2015-01-21 2016-08-17 雷虹桥 Electromagnetic speed control high-speed dual-layer nested bearing

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