JP3490074B2 - Magnetic bearing device - Google Patents

Magnetic bearing device

Info

Publication number
JP3490074B2
JP3490074B2 JP2001281027A JP2001281027A JP3490074B2 JP 3490074 B2 JP3490074 B2 JP 3490074B2 JP 2001281027 A JP2001281027 A JP 2001281027A JP 2001281027 A JP2001281027 A JP 2001281027A JP 3490074 B2 JP3490074 B2 JP 3490074B2
Authority
JP
Japan
Prior art keywords
bearing
touch
rotor
magnetic bearing
touchdown
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
JP2001281027A
Other languages
Japanese (ja)
Other versions
JP2002139037A (en
Inventor
靖一 藤本
拓知 京谷
和夫 六角
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Koyo Seiko Co Ltd
Original Assignee
Koyo Seiko Co Ltd
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Filing date
Publication date
Application filed by Koyo Seiko Co Ltd filed Critical Koyo Seiko Co Ltd
Priority to JP2001281027A priority Critical patent/JP3490074B2/en
Publication of JP2002139037A publication Critical patent/JP2002139037A/en
Application granted granted Critical
Publication of JP3490074B2 publication Critical patent/JP3490074B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • 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
    • F16C39/00—Relieving load on bearings
    • F16C39/02—Relieving load on bearings using mechanical means
    • 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
    • F16C32/044—Active magnetic bearings
    • F16C32/0442—Active magnetic bearings with devices affected by abnormal, undesired or non-standard conditions such as shock-load, power outage, start-up or touchdown
    • 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
    • F16C2300/00—Application independent of particular apparatuses
    • F16C2300/40—Application independent of particular apparatuses related to environment, i.e. operating conditions
    • F16C2300/62—Application independent of particular apparatuses related to environment, i.e. operating conditions low pressure, e.g. elements operating under vacuum conditions
    • 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
    • F16C2360/00—Engines or pumps
    • F16C2360/44—Centrifugal pumps
    • F16C2360/45—Turbo-molecular pumps

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Rolling Contact Bearings (AREA)
  • Magnetic Bearings And Hydrostatic Bearings (AREA)

Description

【発明の詳細な説明】 【０００１】 【発明の属する技術分野】本発明は、真空用機器等に用
いる磁気軸受装置、特に、磁気軸受のロータを支承する
タッチダウン軸受を有する磁気軸受装置に関する。 【０００２】 【従来の技術】例えば、ターボ分子ポンプなどの真空用
機器に組込まれる磁気軸受装置においては、ロータはそ
の高速回転中磁気軸受にて非接触状態に支承され、回転
停止時にはロータが磁気軸受のステータやモータ等に接
触して破損せぬようタッチダウン軸受を設けている。と
ころで、通常の磁気軸受装置の使用停止時には、ロータ
がその回転速度を除々に落とされ、かなり低速になって
からタッチダウン軸受に接触させられるようにしている
ためタッチダウン軸受等の損傷はない。しかし、磁気軸
受装置の使用中に停電等の原因にて瞬時に磁気軸受が作
動しなくなった場合、ロータは高速回転を続けた状態で
タッチダウン軸受に接触し、回転停止するまでタッチダ
ウン軸受にて支承されることにより、ロータの損傷や軸
受寿命が短くなる等の問題がある。これは、タッチダウ
ン軸受の回転輪の瞬時の急加速性が悪いことに起因す
る。上述の問題点を解消するため、特に真空中で使用す
る磁気軸受装置のタッチダウン軸受では、転動体表面に
銀などの金属膜層を形成したのちに二硫化モリブデンな
どの固体潤滑剤を被膜することにより軸受寿命を延長す
る磁気軸受装置（特開昭６１−１６５０２１号）などが
考案されている。 【０００３】 【発明が解決しようとする課題】しかしながら、上述の
場合も、固体潤滑剤の磨耗、剥離が進行するにつれ、タ
ッチダウン軸受の回転トルクが高くなり、タッチダウン
側周面でのすべりの増大、軌道部でのころがり運動のす
べり率の増大により、特に真空中においては上記部材が
容易に高温になり、転動体表面や軌道面あるいはタッチ
ダウン側周面に焼付けが発生し、早期に軸受寿命に到達
してしまう。また、従来、転動体として鋼製の玉を使用
していたので、慣性重量が大きく、タッチダウン軸受の
回転輪の初期トルクが大きくなる。それだけ、タッチダ
ウン軸受内でタッチダウン時のエネルギーを吸収し易く
発熱の原因となる。発熱により、玉や軌道の摩耗、さら
には、高温・高面圧下での接触による凝着現象により早
期焼き付きを招来する。また、玉や軌道面に固体潤滑剤
を塗布した場合には、これら固体潤滑剤の劣化・消失を
来し、結果として、軸受としての耐久性を減じ、早期寿
命に至る。本発明は、上述の問題点を解消するものであ
り、その目的とするところは、タッチダウン軸受の軌道
面および転動面での耐摩耗強度および耐焼付性を向上さ
せ、長期にわたり磁気軸受の電源断時の際のロータを回
転可能に支持しうるようにした磁気軸受装置を提供する
ことにある。 【０００４】 【課題を解決するための手段】本発明の磁気軸受装置
は、ロータを磁気軸受で浮揚状態に支持し、かつ磁気軸
受の電源断時等にタッチダウン用転がり軸受によりロー
タを回転可能に支持するようにした磁気軸受装置におい
て、前記タッチダウン用転がり軸受は、少なくとも回転
輪が鋼で形成されるとともに、すべての転動体がセラミ
ックスからなる総ボール型式として回転輪の初期トルク
を低減し、該タッチダウン用転がり軸受の回転輪のタッ
チダウン側周面に固体潤滑被膜層を形成してなる。そし
て、該固体潤滑被膜層によりロータと回転輪間のすべり
を助長して、タッチダウン直後のタッチダウン用転がり
軸受の急加速を緩和し、タッチダウン用転がり軸受全体
の初期トルクの低減が図られるようになされている。 【０００５】 【作用】例えば、電源断時のように急激な回転トルクが
磁気軸受装置のタッチダウン軸受に作用する場合でも、
セラミックス製転動体の使用により、まず、タッチダウ
ン軸受自体の慣性重量が小さくなり、タッチダウン時の
起動トルクが小さくなる。さらに、セラミックスの硬度
の高さにより、軌道輪に対する接触楕円が小さくなり、
面圧が高くなる。このことは、転動体と回転輪とのすべ
りの発生を極力抑えることになり、これによっても、起
動トルクが小さくなる。起動トルクが小さくなること
は、回転輪の立ち上がりがスムーズに行われることであ
り、したがって、タッチダウン時のエネルギーが効率よ
く回転エネルギーに変換される。結果として、タッチダ
ウン軸受の昇温が抑制され、玉や軌道の摩耗、さらに
は、材料特性（鋼と異種材料）とあいまって、高温・高
面圧下での接触による凝着現象による早期焼き付きを効
果的に防止する。玉や軌道面に固体潤滑剤を塗布した場
合には、これら固体潤滑剤の劣化・消失も防止しうる。
また、セラミックス自体、鋼に比べドライ潤滑性に優
れ、たとえ、固体潤滑剤が劣化・消失しても転動体と軌
道面間の摩擦を効果的に小さくできる。よって、タッチ
ダウン軸受あるいはロータを損傷することなく、長期に
わたりロータに良好に追従して磁気軸受装置の寿命を向
上させうる。 【０００６】 【発明の実施の形態】以下に本発明を実施例について詳
述する。例えば、第１図に示すように、本発明の磁気軸
受装置１は、有底円筒状のケース２内に下端部が細軸４
となる段付き軸受に形成され、かつ該細軸４の下端に円
盤部５を有するロータ３を挿入している。前記ロータ３
の上部は、ケース２の内壁２ａに固定された磁気軸受６
にて支承され、前記ロータ３の下部の円盤部５は、ケー
ス２の底壁２ｂに固定された磁気軸受７と該磁気軸受７
より若干上方でケース２の内壁２ａに固定された磁気軸
受８との間に位置して両磁気軸受７、８にて支承され
る。前記上方の磁気軸受６は、ロータ３の軸線に直交す
る方向に磁力を出すラジアル軸受として作用し、下方の
二個の磁気軸受７、８は、ロータ３の軸線方向すなわち
円盤部５の上下面５ａ、５ｂに直交する方向に磁力を出
すスラスト軸受として作用する。９は高周波モータでロ
ータ３を回転させるためのものである。また磁気軸受６
の上方のケース２の内壁２ａからは半径方向にフランジ
１０が一体に設けられ、該フランジ１０の端部１０ａに
形成した周状凹溝１１内に、タッチダウン軸受として総
ボール形式の深みぞ玉軸受１２が装着固定され、ロータ
３の回転停止時のラジアル負荷を受ける。 【０００７】さらに下方の両磁気軸受７、８のうち、円
盤部５の上面側に配置された磁気軸受８のコアー８ｂの
ロータ３に対向する側面８ａには、タッチダウン軸受と
して二個の総ボール形式のアンギュラ玉軸受１３、１４
が上下に正面組合わせで装着固定されている。この両タ
ッチダウン軸受１３、１４のうち上部の軸受１３により
ロータ３の段付き面３ａおよび細軸４が支承され、下部
の軸受１４によりロータ３の細軸４のみが支承される。
ここで第１図の実施例はロータ３の回転中の状態を示し
ているが、ロータ３の回転停止時にはロータ３はタッチ
ダウン軸受１２、１３、１４のみにて支承され、磁気軸
受６、７、８には非接触状態を保つよう、寸法関係が考
慮されていることはもちろんである。 【０００８】次に前記タッチダウン軸受について詳述す
る。なお、ここでは便宜上タッチダウン軸受１２を代表
して説明するが、他の軸受１３、１４の構成についても
同様であることはいうまでもない。第２図に示すよう
に、タッチダウン軸受１２は、軸受鋼を素材とした内輪
１５、外輪１６、および、内外輪１５、１６の間に介装
された転動体１７である。Ａは、膜厚約数μｍのＴｉＮ
薄膜層であり、タッチダウン時の回転輪となる内輪１５
のタッチダウン側周面すなわち内周面１５１、内輪１５
の軌道面１５２、および外輪１６の軌道面１６１に、ス
パッタリング法、イオンプレーティング法あるいはＣＶ
Ｄ法等のコーティングにより形成されている。前記Ｔｉ
Ｎの薄膜層Ａは、従来の二流化モリブデン等の固体潤滑
剤層に比べ、機械的摩耗に対して強く、長期にわたりタ
ッチダウンに耐えられ、しかも高温での摩耗係数が小さ
く、タッチダウン時の内輪内周面１５１および内外輪の
軌道面１５２、１６１での摩擦係数を小さく、すなわち
摩擦トルクを小さくさせることができ、高温での安定性
と耐焼付性は数段に優れたものとなる。もちろん、真空
中で使用されるタッチダウン軸受に要求される完全ドラ
イ潤滑性も失われることがない。 【０００９】上記薄膜層Ａとしては、ＴｉＮの他ＴｉＣ
なども同等の効果が得られる。さらに、これらを複数積
層にして用いることも可能である。第３図には、従来技
術である銀膜上に二硫化モリブデンを被覆したタッチダ
ウン軸受と、本発明のＴｉＮ層を被覆したタッチダウン
軸受との低真空中３００℃での摩擦係数の変化状態を示
す比較グラフである。第３図から明らかなように、本発
明の軸受の方が、長期間にわたり摩擦係数を小さく維持
できることが明らかである。これは、Ａｇ、ＭO Ｓ2 が
低真空中であっても、わずかに存在する酸素のため、高
温中で酸化が進み、潤滑性を失って行くが、ＴｉＮ層は
高温条件下においても劣化しないことと、高速回転によ
っても剥離しにくいからである。したがって、高温条件
下において高速回転で使用しても、支障なく長期にわた
って軸受機能を発揮することができる。 【００１０】上記実施例では、総ボール形式の玉軸受に
ついて説明したが、保持器付きの玉軸受でもよい。ま
た、他の形式のころがり軸受でもよい。さらにまた、本
発明の他の実施例として第１図および第２図の実施例に
おいて、タッチダウン軸受の回転輪１５の内周面１５１
に対向するロータ３の外周面３１にＴｉＮ薄膜層をコー
ティングにより形成してもよい。 【００１１】 【発明の効果】本発明は、ロータを磁気軸受で浮揚状態
に支持し、かつ磁気軸受の電源断時等にタッチダウン用
転がり軸受によりロータを回転可能に支持するようにし
た磁気軸受装置において、前記タッチダウン用転がり軸
受は、少なくとも回転輪が鋼で形成されるとともに、す
べての転動体がセラミックスからなる総ボール型式とし
て回転輪の初期トルクを低減し、該タッチダウン用転が
り軸受の回転輪のタッチダウン側周面に固体潤滑被膜層
を形成してなる。そして、該固体潤滑被膜層によりロー
タと回転輪間のすべりを助長して、タッチダウン直後の
タッチダウン用転がり軸受の急加速を緩和し、タッチダ
ウン用転がり軸受全体の初期トルクの低減が図られる構
成である。従って、急激な回転トルクが負荷されても、
初期トルクの低減を長時間にわたり可能とし、しかも磁
気軸受の信頼性を向上させ、回転軸や軸受の損傷を防止
でき、磁気軸受装置の寿命を向上させうる。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic bearing device used for vacuum equipment and the like, and more particularly to a magnetic bearing device having a touchdown bearing for supporting a magnetic bearing rotor. 2. Description of the Related Art For example, in a magnetic bearing device incorporated in vacuum equipment such as a turbo molecular pump, a rotor is supported by a magnetic bearing during its high speed rotation in a non-contact state. A touch-down bearing is provided to prevent damage by contact with the bearing stator or motor. By the way, when the normal magnetic bearing device is not used, the rotation speed of the rotor is gradually reduced, and the rotor is brought into contact with the touch-down bearing after a considerably low speed, so that there is no damage to the touch-down bearing and the like. However, if the magnetic bearing does not operate instantaneously due to a power failure during use of the magnetic bearing device, the rotor contacts the touch-down bearing while continuing to rotate at high speed, and the rotor contacts the touch-down bearing until rotation stops. There are problems such as damage to the rotor and shortening of the bearing life due to the support. This is due to poor instantaneous rapid acceleration of the rotating wheel of the touchdown bearing. In order to solve the above-mentioned problems, in particular, in a touch-down bearing of a magnetic bearing device used in a vacuum, a solid lubricant such as molybdenum disulfide is coated after forming a metal film layer such as silver on the rolling element surface. Accordingly, a magnetic bearing device (Japanese Patent Laid-Open No. 61-165021) for extending the life of the bearing has been devised. However, also in the above case, as the solid lubricant wears and separates, the rotational torque of the touch-down bearing increases, and the sliding on the touch-down-side peripheral surface increases. Due to the increase in the sliding rate of the rolling motion on the raceway, the above members easily become hot especially in vacuum, and seizure occurs on the rolling element surface, raceway surface or touch-down side peripheral surface, and the bearing End of life. Further, since a ball made of steel is conventionally used as the rolling element, the inertia weight is large, and the initial torque of the rotating wheel of the touch-down bearing increases. As a result, the energy at the time of touchdown is easily absorbed in the touchdown bearing, which causes heat generation. The heat generation causes wear of the balls and raceways, and furthermore, causes early sticking due to the adhesion phenomenon due to contact at high temperature and high surface pressure. Further, when a solid lubricant is applied to the balls or raceway surfaces, the solid lubricant deteriorates or disappears, and as a result, the durability of the bearing is reduced and the life is shortened. The present invention has been made to solve the above-described problems, and an object of the present invention is to improve the wear resistance and seizure resistance on the raceway surface and the rolling surface of a touch-down bearing, and to improve the magnetic bearing for a long time. An object of the present invention is to provide a magnetic bearing device capable of rotatably supporting a rotor when power is turned off. In the magnetic bearing device of the present invention, the rotor is supported in a floating state by a magnetic bearing, and the rotor can be rotated by a touch-down rolling bearing when the power of the magnetic bearing is cut off. a magnetic bearing device so as to support the said for touchdown rolling bearings, with at least the rotation wheel is formed of steel, the initial torque of all the rolling elements are rotated as a full-ball type made of ceramic wheels
And a solid lubricating coating layer is formed on the touch-down side peripheral surface of the rotating wheel of the touch-down rolling bearing. Then, conducive to slip between the rotor and the rotating wheel by the solid lubricating coating, the rolling for the touch-down immediately after touchdown
The sudden acceleration of the bearing is alleviated, and the initial torque of the entire touchdown rolling bearing is reduced. [0005] For example, even when a sudden rotation torque acts on the touch-down bearing of the magnetic bearing device, such as when the power is turned off,
First, the inertial weight of the touch-down bearing itself is reduced by using the ceramic rolling element, and the starting torque at the time of touch-down is reduced. Furthermore, due to the high hardness of the ceramics, the contact ellipse with the bearing ring becomes smaller,
Surface pressure increases. This minimizes the occurrence of slip between the rolling elements and the rotating wheels, thereby also reducing the starting torque. Decreasing the starting torque means that the rotating wheel rises smoothly, so that the energy at the time of touchdown is efficiently converted to rotational energy. As a result, the rise in temperature of the touch-down bearing is suppressed, and due to the wear of balls and raceways, and the material properties (steel and dissimilar materials), early seizure due to the adhesion phenomenon due to contact under high temperature and high surface pressure. Effectively prevent. When a solid lubricant is applied to the balls and the raceway surface, the deterioration and disappearance of these solid lubricants can be prevented.
Further, the ceramic itself has excellent dry lubricity as compared with steel, and even if the solid lubricant deteriorates or disappears, the friction between the rolling element and the raceway surface can be effectively reduced. Therefore, it is possible to satisfactorily follow the rotor for a long period of time without damaging the touchdown bearing or the rotor, thereby improving the life of the magnetic bearing device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments. For example, as shown in FIG. 1, the magnetic bearing device 1 of the present invention has a thin shaft 4 having a lower end portion in a cylindrical case 2 having a bottom.
And a rotor 3 having a disk portion 5 at the lower end of the narrow shaft 4 is inserted. The rotor 3
The upper part of the magnetic bearing 6 fixed to the inner wall 2a of the case 2
The lower disk portion 5 of the rotor 3 includes a magnetic bearing 7 fixed to the bottom wall 2 b of the case 2 and the magnetic bearing 7.
It is located slightly above and between the magnetic bearings 8 fixed to the inner wall 2a of the case 2 and is supported by the two magnetic bearings 7, 8. The upper magnetic bearing 6 acts as a radial bearing for generating a magnetic force in a direction orthogonal to the axis of the rotor 3, and the two lower magnetic bearings 7, 8 are arranged in the axial direction of the rotor 3, that is, the upper and lower surfaces of the disk 5. It acts as a thrust bearing that produces a magnetic force in a direction perpendicular to 5a, 5b. Reference numeral 9 denotes a high-frequency motor for rotating the rotor 3. Magnetic bearing 6
A flange 10 is integrally provided in a radial direction from an inner wall 2a of the case 2 above the inner case 2 and a deep groove of a total ball type as a touch-down bearing is provided in a circumferential groove 11 formed at an end 10a of the flange 10. The bearing 12 is mounted and fixed, and receives a radial load when the rotation of the rotor 3 is stopped. [0007] Of the two lower magnetic bearings 7 and 8, the core 8b of the magnetic bearing 8 disposed on the upper surface side of the disk portion 5 has a side surface 8a facing the rotor 3 and a total of two touchdown bearings. Ball type angular contact ball bearings 13 and 14
Are mounted and fixed in a front-to-back combination. Of the two touch-down bearings 13, 14, the upper bearing 13 supports the stepped surface 3a and the thin shaft 4 of the rotor 3, and the lower bearing 14 supports only the thin shaft 4 of the rotor 3.
Here, the embodiment of FIG. 1 shows a state in which the rotor 3 is rotating. When the rotation of the rotor 3 is stopped, the rotor 3 is supported only by the touchdown bearings 12, 13, and 14, and the magnetic bearings 6, 7 , 8 take into account the dimensional relationship so as to maintain the non-contact state. Next, the touch-down bearing will be described in detail. Here, the touch-down bearing 12 will be described as a representative for convenience, but it goes without saying that the configuration of the other bearings 13 and 14 is the same. As shown in FIG. 2, the touch-down bearing 12 is an inner ring 15, an outer ring 16 made of bearing steel, and a rolling element 17 interposed between the inner and outer rings 15, 16. A is TiN having a thickness of about several μm.
Inner ring 15 which is a thin film layer and serves as a rotating wheel at the time of touchdown
Touch-down side peripheral surface, that is, inner peripheral surface 151, inner ring 15
On the raceway surface 152 of the outer ring 16 and the raceway surface 161 of the outer ring 16 by sputtering, ion plating or CV.
It is formed by coating such as method D. The Ti
The thin film layer A of N is more resistant to mechanical abrasion than a conventional solid lubricant layer of molybdenum or the like, can withstand touchdown for a long time, has a small wear coefficient at high temperature, The coefficient of friction on the inner peripheral surface 151 of the inner race and the raceway surfaces 152 and 161 of the inner and outer races can be reduced, that is, the friction torque can be reduced, and the stability and seizure resistance at high temperatures are improved several stages. Of course, the complete dry lubricity required for the touchdown bearing used in a vacuum is not lost. The thin film layer A is made of TiC in addition to TiN.
The same effect can be obtained with the above. Furthermore, it is also possible to use a plurality of these layers. FIG. 3 shows the state of change in the coefficient of friction at 300 ° C. in a low vacuum between the touchdown bearing of the prior art in which molybdenum disulfide is coated on a silver film and the touchdown bearing of the present invention in which a TiN layer is coated. FIG. As is clear from FIG. 3, it is clear that the bearing of the present invention can keep the friction coefficient small over a long period of time. This, Ag, even during M O S 2 is low vacuum, because of oxygen present slightly, proceeds oxidation in a high temperature, although we lose lubricity, TiN layer is deteriorated even under high temperature conditions This is because it is not peeled off and it is difficult to peel off even by high-speed rotation. Therefore, even when used at high speed under high temperature conditions, the bearing function can be exhibited for a long time without any trouble. In the above embodiment, a ball bearing of the full ball type has been described. However, a ball bearing with a retainer may be used. Further, other types of rolling bearings may be used. Further, as another embodiment of the present invention, in the embodiment shown in FIGS. 1 and 2, the inner peripheral surface 151 of the rotating ring 15 of the touch-down bearing is used.
May be formed on the outer peripheral surface 31 of the rotor 3 by coating. According to the present invention, there is provided a magnetic bearing in which a rotor is supported in a floating state by a magnetic bearing, and the rotor is rotatably supported by a rolling bearing for touchdown when the power of the magnetic bearing is turned off. In the device, the touch-down rolling bearing has a total ball type in which at least a rotating wheel is formed of steel and all rolling elements are made of ceramics.
Thus, the initial torque of the rotating wheel is reduced, and a solid lubricating coating layer is formed on the touch-down side peripheral surface of the rotating wheel of the touch-down rolling bearing. Then, by the solid lubricating coating layer to promote slip between the rotor and the rotating ring, immediately after touchdown
In this configuration, sudden acceleration of the touch-down rolling bearing is reduced, and the initial torque of the entire touch-down rolling bearing is reduced. Therefore, even if a sudden rotation torque is applied,
It is possible to reduce the initial torque for a long time, improve the reliability of the magnetic bearing, prevent damage to the rotating shaft and the bearing, and improve the life of the magnetic bearing device.

【図面の簡単な説明】 【図１】本発明の一実施例の縦断面図である。 【図２】第１図の実施例におけるタッチダウン軸受の要
部拡大断面図である。 【図３】本発明のタッチダウン軸受と従来のタッチダウ
ン軸受の摩擦係数の変化状態を示す比較グラフである。 【符号の説明】 ３ ロータ ６、７、８ 磁気軸受 １２、１３、１４ タッチダウン軸受 Ａ 固体潤滑膜BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view of one embodiment of the present invention. FIG. 2 is an enlarged sectional view of a main part of the touch-down bearing in the embodiment of FIG. FIG. 3 is a comparison graph showing a change state of a friction coefficient between the touchdown bearing of the present invention and a conventional touchdown bearing. [Description of Signs] 3 Rotors 6, 7, 8 Magnetic bearings 12, 13, 14 Touchdown bearing A Solid lubricating film

───────────────────────────────────────────────────── フロントページの続き (72)発明者 六角 和夫 大阪府大阪市南区鰻谷西之町２番地 光 洋精工株式会社内 (56)参考文献 特開 昭61−165021（ＪＰ，Ａ) 特開 昭61−6169（ＪＰ，Ａ) 特開 昭54−163248（ＪＰ，Ａ) 特開 昭53−131285（ＪＰ，Ａ) 実開 昭60−7420（ＪＰ，Ｕ) 実開 昭61−40510（ＪＰ，Ｕ) (58)調査した分野(Int.Cl.7，ＤＢ名) F16C 32/04 F16C 33/32 F16C 33/66 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Kazuo Hexagon, No. 2, Nishinomachi, Unagiya, Minami-ku, Osaka-shi, Osaka Inside of Hiroyo Seiko Co., Ltd. (56) References JP-A-61-165021 (JP, A) JP-A-61-6169 (JP, A) JP-A-54-163248 (JP, A) JP-A-53-131285 (JP, A) Fully open Showa 60-7420 (JP, U) Really open Showa 61-40510 (JP , U) (58) Field surveyed (Int. Cl. 7 , DB name) F16C 32/04 F16C 33/32 F16C 33/66

Claims (1)

(57)【特許請求の範囲】 （１）ロータを磁気軸受で浮揚状態に支持し、かつ磁気
軸受の電源断時等にタッチダウン用転がり軸受によりロ
ータを回転可能に支持するようにした磁気軸受装置にお
いて、 前記タッチダウン用転がり軸受は、少なくとも回転輪が
鋼で形成されるとともに、すべての転動体がセラミック
スからなる総ボール型式として回転輪の初期トルクを低
減し、該タッチダウン用転がり軸受の回転輪のタッチダ
ウン側周面に固体潤滑被膜層を形成して、 該 固体潤滑被膜層によりロータと回転輪間のすべりを助
長して、タッチダウン直後のタッチダウン用転がり軸受
の急加速を緩和し、タッチダウン用転がり軸受全体の初
期トルクの低減が図られるようになされている磁気軸受
装置。(57) [Claims] (1) A magnetic bearing in which a rotor is supported in a floating state by a magnetic bearing, and the rotor is rotatably supported by a rolling bearing for touchdown when the power of the magnetic bearing is cut off. in the apparatus, the for touch down rolling bearings, with at least the rotation wheel is formed of steel, all rolling elements the initial torque of the rotating wheel as a full-ball type made of ceramics low
A solid lubricating coating layer is formed on the touch-down side peripheral surface of the rotating wheel of the touch-down rolling bearing , and the solid lubricating coating layer promotes a slip between the rotor and the rotating wheel, and the Rolling bearing for touchdown
Magnetic bearing device designed to mitigate sudden acceleration of the bearing and reduce the initial torque of the entire rolling bearing for touchdown.
JP2001281027A 2001-09-17 2001-09-17 Magnetic bearing device Expired - Lifetime JP3490074B2 (en)

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JP2001281027A JP3490074B2 (en) 2001-09-17 2001-09-17 Magnetic bearing device

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
JP9265012A Division JPH10176714A (en) 1997-09-10 1997-09-10 Magnetic bearing device

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JP3490074B2 true JP3490074B2 (en) 2004-01-26

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RU2596201C2 (en) * 2011-09-13 2016-08-27 Роллс-Ройс Аб Method and device for protection of located in fairing from bending shaft in case
KR101408060B1 (en) 2012-06-19 2014-06-18 한국기계연구원 complex magnetic bearing combined with auxiliary bearing

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