JP2005098394A - Fluid bearing device - Google Patents

Fluid bearing device Download PDF

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JP2005098394A
JP2005098394A JP2003333228A JP2003333228A JP2005098394A JP 2005098394 A JP2005098394 A JP 2005098394A JP 2003333228 A JP2003333228 A JP 2003333228A JP 2003333228 A JP2003333228 A JP 2003333228A JP 2005098394 A JP2005098394 A JP 2005098394A
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Prior art keywords
bearing
lubricant
bearing device
shaft
rotating
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Hideaki Ono
英明 大野
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Panasonic Holdings Corp
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Matsushita Electric Industrial Co Ltd
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  • Connection Of Motors, Electrical Generators, Mechanical Devices, And The Like (AREA)
  • Permanent Magnet Type Synchronous Machine (AREA)
  • Sliding-Contact Bearings (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluid bearing device of low torque, without malfunction or failure due to static charged on a rotary part to achieve stability, and a magnetic disc rotation device using that. <P>SOLUTION: This fluid bearing device is composed by filling lubricant with lithium salt added as conductivity providing agent with less effect of increasing viscosity to a bearing gap between a bearing sleeve 5 and a shaft 2. An electricity continuity passage can thus be securely held between the rotary part and a fixed part. The rotary part can thus be prevented from being charged with static, without worsening torque loss at low temperature. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

本発明は、磁気ディスク装置における磁気ディスク駆動用スピンドルモータやポリゴンミラー回転駆動装置が用いられている高速デジタル複写機、レーザープリンタ、ビデオテープレコーダーの回転磁気ヘッド装置等に用いられている軸受部材と軸部材との隙間に充填する潤滑剤を圧力発生流体と利用する流体軸受装置に関するものであり、特に、高速回転の場合に生ずる回転部の静電気の帯電を防止するものである。   The present invention relates to a bearing member used in a high-speed digital copying machine, a laser printer, a rotating magnetic head device of a video tape recorder, etc. in which a magnetic disk drive spindle motor or polygon mirror rotary drive device is used. The present invention relates to a hydrodynamic bearing device that uses a lubricant filling a gap with a shaft member as a pressure generating fluid, and in particular, prevents static charging of a rotating part that occurs during high-speed rotation.

従来、流体軸受装置は、軸受部材と軸部材との隙間に潤滑用の流体を充填するとともに、前記軸受部材の内周面と軸部材の外周面の少なくとも一方に前記流体の圧力を高める動圧発生溝を形成していて、それにより軸受部材または軸部材の回転時に動圧発生溝で圧力上昇を生じさせ、両部材を非接触状態に維持するようにしている。これらの流体軸受装置に用いられている潤滑剤は基油として、鉱物油やポリ−α―オレフィン油、エステル油、シリコーン油、フッ素系油等の合成油が用いられている。   Conventionally, a hydrodynamic bearing device fills a gap between a bearing member and a shaft member with a lubricating fluid and increases dynamic pressure on at least one of the inner peripheral surface of the bearing member and the outer peripheral surface of the shaft member. A generation groove is formed, whereby a pressure increase is generated in the dynamic pressure generation groove when the bearing member or the shaft member is rotated, and both members are maintained in a non-contact state. The lubricants used in these hydrodynamic bearing devices use synthetic oils such as mineral oils, poly-α-olefin oils, ester oils, silicone oils, and fluorine oils as base oils.

流体軸受装置では軸受部材、または軸部材のどちらか一方が非接触状態で高速回転するため、回転部は潤滑剤の流動による帯電が生じる。また磁気ディスクを用いた磁気記録装置に用いた場合、磁気ディスクが空気との摩擦で帯電が生じ潤滑剤を挟み、非接触で回転する回転部材は電荷を蓄えることとなる。磁気テープを用いたVTR等の磁気記録装置に用いた場合、回転シリンダは磁気テープとの摩擦により回転部材は電荷を蓄えることとなる。従来はこの電荷を逃がすため潤滑剤にカーボンブラック、アルキルアリルスルフォン酸塩等の導電性付与剤が添加されていた。(例えば、特許文献1参照。)
特表平11−514778号公報
In the hydrodynamic bearing device, since either the bearing member or the shaft member rotates at a high speed in a non-contact state, the rotating portion is charged by the flow of the lubricant. Further, when used in a magnetic recording apparatus using a magnetic disk, the magnetic disk is charged by friction with air, the lubricant is sandwiched between them, and the rotating member that rotates in a non-contact manner stores electric charges. When used in a magnetic recording device such as a VTR using a magnetic tape, the rotating cylinder stores electric charges due to friction with the magnetic tape. Conventionally, a conductivity-imparting agent such as carbon black or alkyl allyl sulfonate has been added to the lubricant in order to release this charge. (For example, refer to Patent Document 1.)
Japanese National Patent Publication No. 11-514778

解決しようとする問題点は上記のような導電性付与剤を添加すると潤滑剤に対し増粘作用があり、高速回転時のトルク損失の増加、それに伴い発熱による潤滑剤の劣化を生じていたことである。   The problem to be solved is that the addition of the above conductivity-imparting agent has a thickening effect on the lubricant, resulting in an increase in torque loss during high-speed rotation and accompanying deterioration of the lubricant due to heat generation. It is.

本発明は上記問題を解決するもので、回転部材の帯電を防止しつつ、トルク損失が従来よりも低く、耐熱性が高い流体軸受装置を提供することを目的とするものである。   An object of the present invention is to solve the above-described problems, and an object of the present invention is to provide a hydrodynamic bearing device that has lower torque loss and higher heat resistance while preventing charging of a rotating member.

上記問題点を解決するために、本発明の流体軸受装置は、軸受部材と軸部材の少なくとも一方の対向面に動圧発生溝を形成し、前記動圧発生溝が開口した軸受部材と軸部材との隙間に潤滑剤を充填した流体軸受装置において、前記潤滑剤に導電性付与剤としてリチウム塩を添加する。   In order to solve the above problems, a hydrodynamic bearing device according to the present invention includes a bearing member and a shaft member in which a dynamic pressure generating groove is formed on at least one facing surface of the bearing member and the shaft member, and the dynamic pressure generating groove is opened. In the hydrodynamic bearing device in which a gap is filled with a lubricant, a lithium salt is added as a conductivity imparting agent to the lubricant.

また、必要に応じて酸化防止剤、油性向上剤、極圧剤、防錆剤等の公知の各種添加剤を配合することもできる。   Moreover, various well-known additives, such as antioxidant, an oil improvement agent, an extreme pressure agent, and a rust preventive agent, can also be mix | blended as needed.

本発明の流体軸受装置によれば、シャフトと軸受スリーブに挟まれた潤滑剤が導電性付与添加剤を含有することにより回転部位に静電気が蓄積することなく、高速回転等の使用条件下でも安定かつ低トルク損失が実現できる。
また流体軸受装置を用いることにより回転部位に静電気が蓄積することなく、高速回転等
の使用条件下でも安定かつ低トルク損失の磁気ディスク回転装置を提供することができる。
According to the hydrodynamic bearing device of the present invention, the lubricant sandwiched between the shaft and the bearing sleeve contains a conductivity-imparting additive, so that static electricity does not accumulate in the rotating portion, and is stable even under use conditions such as high-speed rotation. And low torque loss can be realized.
Further, by using the hydrodynamic bearing device, it is possible to provide a magnetic disk rotating device that is stable and has a low torque loss even under use conditions such as high-speed rotation without accumulation of static electricity at the rotating portion.

以下、発明の実施の形態について図面を参照しながら説明する。   Hereinafter, embodiments of the invention will be described with reference to the drawings.

(実施の形態1)
図1はハードディスクドライブに使用される流体軸受装置の一例を示し、潤滑剤10以外は従来の流体軸受装置と同様の構成を有しており、外周面に動圧発生溝4a,動圧発生溝4bが形成されたシャフト2の一端がベース1に圧入され、他端にはスラスト受3が固定されて軸部が形成されている。磁気ディスク等を取り付ける為のハブ6の内周面には軸受スリーブ5が圧入されており、この軸受スリーブ5の一端にスラスト板11が取り付けられて軸受体が形成されている。そして、スラスト板11とスラスト受3とが対向するようにシャフト2に軸受スリーブ5が装着され、軸部と軸受体との間隙に潤滑剤10が充填される。
(Embodiment 1)
FIG. 1 shows an example of a hydrodynamic bearing device used in a hard disk drive, which has the same configuration as that of a conventional hydrodynamic bearing device except for a lubricant 10, and has a dynamic pressure generating groove 4a and a dynamic pressure generating groove on the outer peripheral surface. One end of the shaft 2 on which 4b is formed is press-fitted into the base 1, and a thrust receiver 3 is fixed to the other end to form a shaft portion. A bearing sleeve 5 is press-fitted into the inner peripheral surface of the hub 6 for attaching a magnetic disk or the like, and a thrust plate 11 is attached to one end of the bearing sleeve 5 to form a bearing body. Then, the bearing sleeve 5 is mounted on the shaft 2 so that the thrust plate 11 and the thrust receiver 3 face each other, and a lubricant 10 is filled in the gap between the shaft portion and the bearing body.

ベース1に形成された外壁1aにはステータコイル9が設けられ、ステータコイル9と対向するハブ6の内周面にはロータヨーク8を介してロータマグネット7が取り付けられて、モータ駆動部が構成される。   A stator coil 9 is provided on the outer wall 1a formed on the base 1, and a rotor magnet 7 is attached to the inner peripheral surface of the hub 6 facing the stator coil 9 via a rotor yoke 8, thereby constituting a motor drive unit. The

このモータ駆動部により軸受スリーブ5およびハブ6が回転駆動すると、シャフト2に形成された動圧発生溝4a、動圧発生溝4bのポンピング作用により潤滑剤10に動圧が発生し、軸受体が軸部から浮上して、軸部と軸受体とが非接触で回転自在に支持される。   When the bearing sleeve 5 and the hub 6 are rotationally driven by the motor drive unit, dynamic pressure is generated in the lubricant 10 by the pumping action of the dynamic pressure generating groove 4a and the dynamic pressure generating groove 4b formed in the shaft 2, and the bearing body is The shaft floats from the shaft portion, and the shaft portion and the bearing body are rotatably supported without contact.

なお、動圧発生溝4a、動圧発生溝4bは、シャフト2の外周面と軸受スリーブ5の内周面の一方、もしくは両方に形成するようにしてもよく、また、スラスト動圧発生溝を、スラスト受3とスラスト板11の対向面の一方あるいは両方に形成するようにしてもよい。また、ラジアル側およびスラスト側動圧発生溝とも、対向面間の隙間で潤滑剤10の圧力が上昇する形状であればよく、屈折部を持たせたり、深さを変えるなど、種々可能である。また、軸部が回転し、軸受スリーブ5が固定される流体軸受装置であってもよい。   The dynamic pressure generating groove 4a and the dynamic pressure generating groove 4b may be formed on one or both of the outer peripheral surface of the shaft 2 and the inner peripheral surface of the bearing sleeve 5, and the thrust dynamic pressure generating groove is formed. Alternatively, it may be formed on one or both of the opposing surfaces of the thrust receiver 3 and the thrust plate 11. Further, both the radial side and thrust side dynamic pressure generating grooves may have a shape in which the pressure of the lubricant 10 increases in the gap between the opposing surfaces, and various forms such as providing a refracting portion and changing the depth are possible. . Further, a fluid bearing device in which the shaft portion rotates and the bearing sleeve 5 is fixed may be used.

ここで、本発明の流体軸受装置の特徴は潤滑剤10にあるので、以下リチウム塩の一例を挙げて説明する。   Here, since the characteristic of the hydrodynamic bearing device of the present invention resides in the lubricant 10, an example of a lithium salt will be described below.

本発明の流体軸受装置は前述したように非接触で保持された、回転部位と固定部位の間の潤滑剤10にリチウム−ビス−トリフルオロメタン−スルホンイミドやリチウム−ビス−ペンタフルオロエタン−スルホンイミド等のリチウム塩を添加することによって、常に一定の導電性を潤滑剤に付与することができ、回転部位と固定部位の間の電気導通経路を確実に保つことが出来る。   As described above, the hydrodynamic bearing device of the present invention has lithium-bis-trifluoromethane-sulfonimide or lithium-bis-pentafluoroethane-sulfonimide in the lubricant 10 held in a non-contact manner between the rotating portion and the fixed portion. By adding a lithium salt such as the above, constant conductivity can be imparted to the lubricant, and the electrical conduction path between the rotating part and the fixed part can be reliably maintained.

(実施の形態2)
次に、本発明の磁気ディスク回転装置の一例について説明する。図2において、軸回転型の流体軸受を組み込んだ磁気ディスク回転装置は、3枚の磁気ディスク33はスペーサ32を間に挟んだ状態でハブ30に積層され、クランプ31で固定されている。ハブ30の内周側にはロータマグネット29が設けられており、固定側に設けられているステータコイル28との間でモータを形成し、磁気ディスク33やハブ30等の回転部を高速で回転駆動する。
(Embodiment 2)
Next, an example of the magnetic disk rotating device of the present invention will be described. In FIG. 2, in a magnetic disk rotating apparatus incorporating a shaft-rotating type fluid bearing, three magnetic disks 33 are stacked on a hub 30 with a spacer 32 interposed therebetween, and are fixed by a clamp 31. A rotor magnet 29 is provided on the inner peripheral side of the hub 30, and a motor is formed with the stator coil 28 provided on the fixed side, and rotating parts such as the magnetic disk 33 and the hub 30 are rotated at high speed. To drive.

ステータコイル28は軸受スリーブ22の外周に設けられており、軸受スリーブ22はアースにつながるベース27に固定されている。ハブ30にはシャフト21が圧入されて
おり、シャフト21は軸受スリーブ22に挿入され、スラスト受23を取り付ける。軸受スリーブ22のベース27側の開口部にスラスト板24を固定する。
The stator coil 28 is provided on the outer periphery of the bearing sleeve 22, and the bearing sleeve 22 is fixed to a base 27 connected to the ground. A shaft 21 is press-fitted into the hub 30, and the shaft 21 is inserted into a bearing sleeve 22 to which a thrust receiver 23 is attached. The thrust plate 24 is fixed to the opening on the base 27 side of the bearing sleeve 22.

シャフト21と軸受スリーブ22間、スラスト受23と軸受スリーブ22間およびスラスト受23とスラスト板24間のスラスト隙間およびラジアル隙間には導電性付与剤としてリチウム塩を添加した潤滑剤26を充填している。シャフト21と軸受スリーブ22、スラスト受23とスラスト板24がそれぞれ対向する面の少なくとも一方には動圧発生溝を設けており、回転に伴って生じる動圧によってシャフト21は浮上する。   A thrust gap and a radial gap between the shaft 21 and the bearing sleeve 22, between the thrust receiver 23 and the bearing sleeve 22, and between the thrust receiver 23 and the thrust plate 24 are filled with a lubricant 26 added with lithium salt as a conductivity-imparting agent. Yes. A dynamic pressure generating groove is provided on at least one of the surfaces where the shaft 21 and the bearing sleeve 22, the thrust receiver 23 and the thrust plate 24 face each other, and the shaft 21 floats due to the dynamic pressure generated by the rotation.

以上の構成において、磁気ディスク33に接するスペーサ32やクランプ31に例えば、金属や導電性樹脂等の導電性材料を用いることにより、磁気ディスク33とハブ30を電気的に接続することができる。ハブ30は通常、アルミニウムや鉄系の金属材料からなり、圧入されたシャフト21と電気的に等価となっている。従って、磁気ディスク33は、潤滑剤を介して軸受スリーブ22と電気的に接続された構造となり、磁気ディスク33に発生した静電気はベース27に放出されることとなる。   In the above configuration, the magnetic disk 33 and the hub 30 can be electrically connected by using, for example, a conductive material such as metal or conductive resin for the spacer 32 and the clamp 31 that are in contact with the magnetic disk 33. The hub 30 is usually made of aluminum or an iron-based metal material, and is electrically equivalent to the press-fitted shaft 21. Accordingly, the magnetic disk 33 is electrically connected to the bearing sleeve 22 via the lubricant, and static electricity generated in the magnetic disk 33 is discharged to the base 27.

なお、軸受スリーブ回転型においても同様に回転部材に固着された磁気ディスクで発生した静電気は、導電性付与剤としてリチウム塩を添加した潤滑剤を介してベースに放出されることとなる。   Similarly, in the bearing sleeve rotating type, static electricity generated on the magnetic disk fixed to the rotating member is discharged to the base via a lubricant added with lithium salt as a conductivity imparting agent.

本発明の流体軸受装置と従来の流体軸受装置とを、実施の形態2で説明した磁気記録用ディスク回転装置に組み込んで磁気ディスクを取り外した状態で、20℃雰囲気で245ミリアンペアの消費電流で回転するモータユニットを用いて特性比較を行った。なお、比較した実機回転体は単一個体を洗浄し組み替えた。   The hydrodynamic bearing device of the present invention and the conventional hydrodynamic bearing device are incorporated into the magnetic recording disk rotating device described in the second embodiment, and the magnetic disk is detached and rotated at a current consumption of 245 milliamperes in an atmosphere of 20 ° C. The characteristics were compared using the motor unit. In addition, the compared real machine rotator was cleaned and recombined.

流体軸受装置の基油にはジオクチルセバシン酸(ガスクロマトグラフィーで純度99.8%)を用い、市販の酸化防止剤、油性向上剤、極圧剤、防錆剤等の公知の各種添加剤を配合した軸受油を従来例Aとした。本発明の実施例Aの軸受油は、上記従来例Aの軸受油を100重量部としたとき、リチウム塩としてリチウム−ビス−トリフルオロメタン−スルホンイミドを2重量部添加したものである。同様に実施例Bの軸受油は、リチウム塩としてリチウム−ビス−ペンタフルオロエタン−スルホンイミドを2重量部添加したものである。一方、従来例Bの軸受油は、炭素数8〜12からなるのリニアアルキルベンゼンスルホン酸Na塩を2重量部添加したものである。従来例Cとして微粒子カーボンブラックとして知られるキェッチェンブラックを添加したサンプルを作成したが軸受油に分散せず、分離したため今回の実験では測定していない。   Dioctyl sebacic acid (purity 99.8% by gas chromatography) is used for the base oil of the hydrodynamic bearing device, and various known additives such as commercially available antioxidants, oiliness improvers, extreme pressure agents, and rust inhibitors are used. The blended bearing oil was designated as Conventional Example A. The bearing oil of Example A of the present invention is obtained by adding 2 parts by weight of lithium-bis-trifluoromethane-sulfonimide as a lithium salt when the bearing oil of Conventional Example A is 100 parts by weight. Similarly, the bearing oil of Example B is obtained by adding 2 parts by weight of lithium-bis-pentafluoroethane-sulfonimide as a lithium salt. On the other hand, the bearing oil of Conventional Example B is obtained by adding 2 parts by weight of a linear alkylbenzene sulfonic acid Na salt having 8 to 12 carbon atoms. A sample to which Ketjen Black, known as fine particle carbon black, was added as Conventional Example C was prepared, but it was not dispersed in the bearing oil and separated, so it was not measured in this experiment.

ここで、特性比較として測定した値(消費電流、回転部と固定部の間の電気抵抗値)を以下の表に示す。   Here, values (current consumption, electric resistance value between the rotating part and the fixed part) measured as characteristic comparison are shown in the following table.

Figure 2005098394
Figure 2005098394

このように本発明の流体軸受装置は、従来例のように大きなトルク損失を発生すること
なく、回転部位と固定部位の間の電気導通経路を確保することができる。
Thus, the hydrodynamic bearing device of the present invention can secure an electrical conduction path between the rotating part and the fixed part without generating a large torque loss as in the conventional example.

本発明の流体軸受装置は磁気記録装置など、静電気の帯電を嫌う精密軸受などに有用である。   The hydrodynamic bearing device of the present invention is useful for precision bearings and the like that do not like electrostatic charging, such as magnetic recording devices.

本発明の一実施の形態における流体軸受装置の断面図Sectional drawing of the hydrodynamic bearing apparatus in one embodiment of this invention 本発明の一実施の形態における磁気ディスク回転装置の断面図Sectional drawing of the magnetic-disk rotating apparatus in one embodiment of this invention

符号の説明Explanation of symbols

1 ベース
2 シャフト
3 スラスト受
4a、4b 動圧発生溝
5 軸受スリーブ
6 ハブ
7 ロータマグネット
8 ロータヨーク
9 ステータコイル
10、26 潤滑剤
11 スラスト板
31 クランプ
32 スペーサ
33 磁気ディスク

DESCRIPTION OF SYMBOLS 1 Base 2 Shaft 3 Thrust receiving 4a, 4b Dynamic pressure generating groove 5 Bearing sleeve 6 Hub 7 Rotor magnet 8 Rotor yoke 9 Stator coil 10, 26 Lubricant 11 Thrust plate 31 Clamp 32 Spacer 33 Magnetic disk

Claims (2)

スリーブの軸受穴に挿入された軸と軸受隙間に潤滑剤が充填された流体軸受装置において、その潤滑剤に導電性付与剤としてリチウム塩を添加したことを特徴する流体軸受装置。 A hydrodynamic bearing device in which a lubricant is added to a lubricant in a fluid bearing device in which a lubricant is filled in a bearing gap between a shaft inserted into a bearing hole of a sleeve. 請求項1に記載の流体軸受装置を搭載した磁気記録用ディスク回転装置。
A disk rotating device for magnetic recording on which the hydrodynamic bearing device according to claim 1 is mounted.
JP2003333228A 2003-09-25 2003-09-25 Fluid bearing device Pending JP2005098394A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2017197716A (en) * 2016-04-21 2017-11-02 コスモ石油ルブリカンツ株式会社 Conductive lubricant composition

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JP2017197716A (en) * 2016-04-21 2017-11-02 コスモ石油ルブリカンツ株式会社 Conductive lubricant composition

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