JPH0730789B2 - Hydrostatic / magnetic bearing spindle - Google Patents
Hydrostatic / magnetic bearing spindleInfo
- Publication number
- JPH0730789B2 JPH0730789B2 JP2316998A JP31699890A JPH0730789B2 JP H0730789 B2 JPH0730789 B2 JP H0730789B2 JP 2316998 A JP2316998 A JP 2316998A JP 31699890 A JP31699890 A JP 31699890A JP H0730789 B2 JPH0730789 B2 JP H0730789B2
- Authority
- JP
- Japan
- Prior art keywords
- bearing
- spindle
- magnetic bearing
- hydrostatic
- gap
- 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
Links
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
- 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
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Magnetic Bearings And Hydrostatic Bearings (AREA)
Description
【発明の詳細な説明】 （産業上の利用分野） 本発明は、磁気軸受スピンドルにおいて保護ベアリング
を改良することによりスピンドルの回転性能を向上させ
たものに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic bearing spindle in which the rotational performance of the spindle is improved by improving a protective bearing.
（従来の技術） 能動形磁気軸受には、制御装置の故障や過大な外乱など
の不慮の事故に対処するため、保護ベアリングが取付け
られている。(Prior Art) A protective bearing is attached to an active magnetic bearing in order to cope with an unexpected accident such as a failure of a control device or an excessive disturbance.
保護ベアリングにはころがり軸受が採用されており、こ
のころがり軸受と軸との隙間は0.1mmないし、場合によ
っては1.0mm程度まで、軸受としては非常に広くとられ
ている。これはスピンドルとして成立させるためには、
不慮の事態には保護ベアリングのころがり軸受が軸を支
持できることと、通常の運転では軸が保護ベアリングに
接触することがないように、安全上の観点からほぼこの
ような値になっている。A rolling bearing is adopted as the protective bearing, and the clearance between the rolling bearing and the shaft is 0.1 mm or even 1.0 mm in some cases, which is very wide as a bearing. To make this a spindle,
In case of unforeseen circumstances, the rolling bearing of the protective bearing can support the shaft, and in normal operation, the shaft does not come into contact with the protective bearing.
磁気軸受を構成する電磁石のロータとステータとの隙間
は、軸が保護ベアリングに接触してもロータとステータ
が当たらないようにさらに広くされている。The gap between the rotor and the stator of the electromagnet that constitutes the magnetic bearing is further widened so that the rotor and the stator do not come into contact with each other even if the shaft contacts the protective bearing.
また、磁気軸受の故障時や停止時にあたって、回転部分
が保護ベアリングに着地した場合には、軸の運動が必ず
しも安定でなく軸受に対して極めて高い応力が加わり破
損する場合がある。Further, when the rotating portion lands on the protective bearing when the magnetic bearing fails or is stopped, the movement of the shaft is not always stable and extremely high stress is applied to the bearing, which may damage the bearing.
そこで、特開平１−316512号公報では、保護ベアリング
として、ころがり軸受でなく、無潤滑又は自己潤滑材料
からなるステータとクロム鋼、炭化タングステン、セラ
ミックス等の高硬度材からなるロータを設け滑り軸受と
し、負荷能力を向上し、さらに、水等の流体をステータ
とロータ間に注入するようにさせ、保護ベアリングの軸
受潤滑性能を向上させたものが開示されている。In view of this, in Japanese Patent Laid-Open No. 1-316512, a sliding bearing is provided as a protective bearing by providing a stator made of a non-lubricated or self-lubricating material and a rotor made of a high hardness material such as chrome steel, tungsten carbide, ceramics, etc. It is disclosed that the load capacity is improved and a fluid such as water is injected between the stator and the rotor to improve the bearing lubrication performance of the protective bearing.
また、このものでも、保護ベアリングの軸受隙間（ロー
タとステータとの間の空隙）は具体例として0.1mmと記
載され、保護ベアリングの隙間は軸と磁気軸受とのエア
ギャップの約半分と記載されており、前述したと同様に
軸と軸受との隙間は大きい値であった。Also in this case, the bearing gap of the protective bearing (gap between the rotor and the stator) is described as 0.1 mm as a specific example, and the gap of the protective bearing is described as about half the air gap between the shaft and the magnetic bearing. As described above, the gap between the shaft and the bearing has a large value.
（考案が解決しようとする課題） しかし、係る広い隙間では、磁気軸受の性能をあげるた
めに制御回路の増幅度をあげると、軸の位置が設定値よ
り少しでもずれると増幅回路がすぐ飽和してしまい制御
不能となるので、軸の位置を検出する感度をあげること
ができない。従って、軸受の精度、剛性を向上させるこ
とができないという問題があった。(Problems to be solved by the invention) However, in such a wide clearance, if the amplification degree of the control circuit is increased to improve the performance of the magnetic bearing, the amplification circuit will be saturated immediately if the shaft position deviates even a little from the set value. Since it becomes impossible to control, the sensitivity for detecting the axis position cannot be increased. Therefore, there is a problem that the precision and rigidity of the bearing cannot be improved.
さらに、前述した従来のような保護ベアリングでは、磁
気軸受の制御装置の故障や過大な外乱などに対しては有
効であるが、本来スピンドルの軸回転時には軸を磁気軸
受のみで支持するようにされているので、工作機用スピ
ンドルのように主軸の精度、剛性を必要とする用途には
不十分であった。また、スピンドル運転中に磁気軸受と
保護軸受を併用することはできず、併用することの示唆
も開示もされていない。Further, the above-mentioned conventional protective bearing is effective against a failure of the control device of the magnetic bearing and an excessive disturbance, but originally, when the spindle shaft rotates, the shaft is supported only by the magnetic bearing. Therefore, it is not sufficient for applications that require precision and rigidity of the spindle such as machine tool spindles. Further, the magnetic bearing and the protective bearing cannot be used together during the spindle operation, and neither suggestion nor disclosure of using them together is made.
本発明は、保護ベアリングの形式、構造及び材質を改善
して許容隙間を可能な限り狭くし、それに伴って増幅回
路の感度を上げ、磁気軸受スピンドルの精度、剛性を大
きく向上させるものである。The present invention improves the type, structure and material of the protective bearing to make the allowable gap as narrow as possible, thereby increasing the sensitivity of the amplifier circuit and greatly improving the precision and rigidity of the magnetic bearing spindle.
（課題を解決するための手段） このため本発明は、磁気軸受スピンドルにおいて、従来
の保護ベアリングを主軸を支持する静圧軸受とする。そ
して、主軸と能動形磁気軸受との隙間を主軸と静圧軸受
の隙間に静圧軸受の定格許容変位を加えた値より大きく
設定する。さらに、スピンドル運転中には能動形磁気軸
受と静圧軸受との両方で主軸を同時に支持するようにし
たことを特徴とする静圧・磁気軸受スピンドルを提供す
ることによって従来技術の課題を解決した。(Means for Solving the Problem) Therefore, in the present invention, in the magnetic bearing spindle, the conventional protective bearing is a hydrostatic bearing that supports the main shaft. Then, the gap between the main shaft and the active magnetic bearing is set to be larger than the value obtained by adding the rated permissible displacement of the hydrostatic bearing to the gap between the main shaft and the hydrostatic bearing. Furthermore, the problem of the prior art was solved by providing a hydrostatic / magnetic bearing spindle characterized in that both the active magnetic bearing and the hydrostatic bearing support the spindle simultaneously during spindle operation. .
（作用） 係る構成により、静圧軸受は単独で軸を支持可能に設計
されているので、従来の保護ベアリングと同様に能動形
磁気軸受の制御ができなくなっても、静圧軸受によって
軸を確実に支持することができる。(Operation) With this configuration, the hydrostatic bearing is designed to support the shaft independently, so even if the active magnetic bearing cannot be controlled like the conventional protective bearing, the hydrostatic bearing can secure the shaft. Can be supported by.
かつ、静圧軸受と能動形磁気軸受を同時に作用させるよ
うにしたので、軸重量は主として静圧軸受によって支持
され、軸の振れに対する応答は主として能動形磁気軸受
によって制御される。さらに、静圧軸受と能動形磁気軸
受とによって軸を同時に浮上支持するので隙間を小さく
でき、軸受全体としての剛性および精度が向上する。Further, since the hydrostatic bearing and the active magnetic bearing are simultaneously operated, the shaft weight is mainly supported by the hydrostatic bearing, and the response to the runout of the shaft is mainly controlled by the active magnetic bearing. Further, since the shaft is simultaneously levitated and supported by the hydrostatic bearing and the active magnetic bearing, the gap can be reduced, and the rigidity and accuracy of the entire bearing are improved.
（実施例） 第１図および第２図に本発明の一実施例をしめす。図に
おいて１はスピンドルの主軸、２は外筒、３は主軸を駆
動するモータ、４はスピンドルヘッド側のラジアル磁気
軸受、５はスピンドルテール側のラジアル磁気軸受、６
はスラスト磁気軸受、７および８は各ラジアル方向の軸
位置を検出するセンサ、９はスピンドルの前蓋、10は同
じく後蓋を示している。主軸１の中央部にはラジアル静
圧空気軸受のロータ部11が形成され、外筒２に形成され
たラジアル静圧空気軸受のステータ部12と対抗してラジ
アル方向の保護／支持ベアリングとなっている。(Embodiment) FIG. 1 and FIG. 2 show an embodiment of the present invention. In the figure, 1 is a spindle main shaft, 2 is an outer cylinder, 3 is a motor for driving the spindle, 4 is a radial magnetic bearing on the spindle head side, 5 is a radial magnetic bearing on the spindle tail side, 6
Is a thrust magnetic bearing, 7 and 8 are sensors for detecting axial positions in each radial direction, 9 is a front lid of the spindle, and 10 is a rear lid. A rotor portion 11 of a radial static pressure air bearing is formed in the center of the main shaft 1, and serves as a radial protection / support bearing against the stator portion 12 of the radial static pressure air bearing formed on the outer cylinder 2. There is.
外筒２には空気通路13が穿設されており、図示しない圧
縮空気源から送られた圧縮空気が、ラジアル静圧空気軸
受のステータ部12に設けられた多数のノズル14からロー
タ部11に向けて噴出するようにされている。また、ロー
タ部には静圧空気軸受性能を良くするための浅い円周溝
15が設けられている。この保護／支持ベアリングである
ラジアル静圧空気軸受のロータ部11とステータ部とのエ
アーギャップは25μｍであり、定格許容変位は10μｍで
ある。一方ラジアル磁気軸受の電磁石と主軸とのエアー
ギャップを２倍の約50μｍに設定されている。スラスト
磁気軸受６の部分は第２図に拡大して示すように、主軸
１に固着されたスラスト磁気軸受用ロータ16を挟んでそ
の両側にステータ17,17aが設けられている。このステー
タの中心よりには、耐熱、耐摩耗のセラミック製カラー
18,18aが固着されており、これに対向するロータ16に部
分にセラミックコーティング19,19aが施され、スラスト
用の保護ベアリングを形成し、静圧空気軸受は併用して
いない。その理由は、本実施例においては、スラスト磁
気軸受のロータ16,ステータ17を構成する材質が鉄の一
体物であるため、渦電流が発生して高速応答ができず剛
性を上げられないため、隙間を狭くしても無意味だから
である。従って、従来と同様スラスト磁気軸受のロータ
とステータとの間のギャップは0.2mm、保護ベアリング
のギャップは0.1mmとされている。An air passage 13 is bored in the outer cylinder 2, and compressed air sent from a compressed air source (not shown) flows from a large number of nozzles 14 provided in the stator portion 12 of the radial static pressure air bearing to the rotor portion 11. It is supposed to gush toward. In addition, the rotor part has a shallow circumferential groove to improve hydrostatic air bearing performance.
15 are provided. The air gap between the rotor portion 11 and the stator portion of the radial static pressure air bearing which is the protection / support bearing is 25 μm, and the rated permissible displacement is 10 μm. On the other hand, the air gap between the electromagnet of the radial magnetic bearing and the spindle is doubled to about 50 μm. As shown in the enlarged view of FIG. 2, the thrust magnetic bearing 6 is provided with stators 17, 17a on both sides of the thrust magnetic bearing rotor 16 fixed to the main shaft 1 with the thrust magnetic bearing rotor 16 interposed therebetween. From the center of this stator, a heat-resistant and wear-resistant ceramic collar
18, 18a are fixedly attached, and a portion of the rotor 16 facing this is coated with a ceramic coating 19, 19a to form a protective bearing for thrust, and a hydrostatic air bearing is not used together. The reason for this is that in the present embodiment, the rotor 16 of the thrust magnetic bearing and the stator 17 are made of an integral material of iron, so an eddy current is generated and high-speed response cannot be achieved, and the rigidity cannot be increased. This is because it is meaningless to narrow the gap. Therefore, the gap between the rotor and the stator of the thrust magnetic bearing is 0.2 mm and the gap of the protective bearing is 0.1 mm, as in the conventional case.
（実験例） 係る実施例において、ラジアル磁気軸受の電磁石を制御
する制御回路の増幅度を軸の変位つまりラジアル静圧空
気軸受の定格許容変位の10μｍで飽和するように設定し
て運転した。その結果を第３図に示す。第３図は軸剛性
の周波数特性を示すものである。第３図に示すように一
般に磁気軸受の動剛性は周波数特性をもつ。スピンドル
としては、静剛性より動剛性の最低値が重要であり、動
剛性を強くすることが望まれる。従来の能動形磁気軸受
では第３図下方に示すように動剛性の最低値はベストデ
ータで100gf/μｍである。また、空気軸受のみの剛性は
周波数特性の影響は少なく第３図中程に示すように２〜
5kgf/μｍである。(Experimental example) In such an example, the amplification degree of the control circuit for controlling the electromagnet of the radial magnetic bearing was set to be saturated at the axial displacement, that is, 10 μm of the rated permissible displacement of the radial static pressure air bearing for operation. The results are shown in FIG. FIG. 3 shows frequency characteristics of shaft rigidity. As shown in FIG. 3, the dynamic rigidity of the magnetic bearing generally has frequency characteristics. For the spindle, the minimum value of the dynamic rigidity is more important than the static rigidity, and it is desirable to increase the dynamic rigidity. In the conventional active type magnetic bearing, the minimum value of dynamic rigidity is 100 gf / μm in the best data as shown in the lower part of FIG. In addition, the rigidity of the air bearing alone is less affected by the frequency characteristics, as shown in the middle of FIG.
It is 5 kgf / μm.
従って、空気軸受に磁気軸受の剛性を付加した場合に
は、トータル動剛性の最低値は２〜5kgf/μｍの空気軸
受剛性に磁気軸受の最低剛性値を加えた程度と予想され
た。Therefore, when the rigidity of the magnetic bearing is added to the air bearing, the minimum value of the total dynamic rigidity is expected to be about the sum of the air bearing rigidity of 2 to 5 kgf / μm and the minimum rigidity value of the magnetic bearing.
しかし、本発明の動剛性の最低値は10kgf/μｍをかるく
越えるものとなった。これは、静圧空気軸受の併用によ
り隙間を小さくするようにしたので、磁気軸受の感度を
充分に上げることができ、結果、相乗効果を生じたもの
と考える。However, the minimum value of the dynamic rigidity of the present invention exceeded 10 kgf / μm. This is because it is possible to sufficiently increase the sensitivity of the magnetic bearing because the gap is made small by using the static pressure air bearing together, and as a result, it is considered that a synergistic effect is produced.
また、精度についても低速回転での精度が格段に向上し
た。第４図にリサージュ波形での本発明と従来のものと
の比較を示す。なお、センサーターゲットの精度が直接
現れて、高速回転では外筒の振動が大きくなるという問
題があるが、これはまた別の問題でありターゲットの加
工精度の向上等で対処すべきものである。In addition, the accuracy at low speed rotation has been greatly improved. FIG. 4 shows a comparison between the present invention and the conventional one in the Lissajous waveform. There is a problem that the accuracy of the sensor target directly appears and the vibration of the outer cylinder increases at high speed rotation, but this is another problem and should be addressed by improving the processing accuracy of the target.
（発明の効果） 本発明においては、磁気軸受スピンドルの保護ベアリン
グを静圧軸受とするとともに、能動形磁気軸受の隙間を
静圧軸受の隙間に静圧軸受の定格許容変位を加えた値よ
り大きくし、スピンドル運転中に能動形磁気軸受と静圧
軸受とで主軸を同時に浮上支持するようにしたので、保
護ベアリングとしての機能を満足するとともに、スピン
ドル運転中の軸隙間を小さくでき、容易に能動形磁気軸
受の感度をあげることができるので、スピンドル主軸の
精度、剛性を格段に向上させることができた。(Effect of the Invention) In the present invention, the protective bearing of the magnetic bearing spindle is a hydrostatic bearing, and the gap of the active magnetic bearing is larger than the value obtained by adding the rated permissible displacement of the hydrostatic bearing to the gap of the hydrostatic bearing. In addition, since the main shaft is simultaneously levitated and supported by the active magnetic bearing and the hydrostatic bearing during spindle operation, the function as a protective bearing is satisfied and the shaft gap during spindle operation can be reduced, which facilitates active operation. Since the sensitivity of the magnetic bearing can be increased, the precision and rigidity of the spindle spindle can be greatly improved.
第１図は本発明の一実施例を示す縦断面図、第２図は第
１図のII部分の拡大図、第３図は軸剛性の周波数特性に
ついて本発明と従来技術との比較を示すグラフ、第４図
はリサージュ波形についての比較図である。 １……主軸、２……外筒、３……モータ、4,5……ラジ
アル磁気軸受 ６……スラスト磁気軸受、7,8……センサ、11……静圧
空気軸受ロータ、 12……静圧空気軸受ステータ、13……空気通路、14……
空気ノズル、 16……スラスト磁気軸受ロータ、17,17a……スラスト磁
気軸受ステータ、 18,18a……セラミック製カラー、19,19aセラミックコー
ティング。FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention, FIG. 2 is an enlarged view of a portion II in FIG. 1, and FIG. 3 is a comparison between the present invention and a conventional technique with respect to frequency characteristics of shaft rigidity. The graph and FIG. 4 are comparison diagrams regarding the Lissajous waveform. 1 ... spindle, 2 ... outer cylinder, 3 ... motor, 4,5 ... radial magnetic bearing 6 ... thrust magnetic bearing, 7,8 ... sensor, 11 ... hydrostatic air bearing rotor, 12 ... Hydrostatic air bearing stator, 13 ... Air passage, 14 ...
Air nozzle, 16 …… Thrust magnetic bearing rotor, 17,17a …… Thrust magnetic bearing stator, 18,18a …… Ceramic collar, 19,19a Ceramic coating.
Claims (1)
で支持する能動形磁気軸受と、能動形磁気軸受における
主軸の位置を制御する制御装置と、主軸の位置が制御不
能となったときに主軸を支持する保護ベアリングを備え
た磁気軸受スピンドルにおいて、保護ベアリングを主軸
を支持する静圧軸受とし、前記主軸と前記能動形磁気軸
受との隙間を前記主軸と前記静圧軸受の隙間に前記静圧
軸受の定格許容変位を加えた値より大きく設定し、スピ
ンドル運転中に前記能動形磁気軸受と前記静圧軸受とで
主軸を同時に支持するようにしたことを特徴とする静圧
・磁気軸受スピンドル。1. A motor for rotating a spindle, an active magnetic bearing for supporting the spindle in a non-contact manner, a control device for controlling the position of the spindle in the active magnetic bearing, and when the position of the spindle becomes uncontrollable. In a magnetic bearing spindle having a protective bearing for supporting the main shaft, the protective bearing is a static pressure bearing for supporting the main shaft, and a gap between the main shaft and the active magnetic bearing is provided in a gap between the main shaft and the static pressure bearing. The static pressure / magnetic bearing is set to be larger than the value obtained by adding the rated permissible displacement of the static pressure bearing so that the spindle is simultaneously supported by the active magnetic bearing and the static pressure bearing during spindle operation. spindle.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2316998A JPH0730789B2 (en) | 1990-11-21 | 1990-11-21 | Hydrostatic / magnetic bearing spindle |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2316998A JPH0730789B2 (en) | 1990-11-21 | 1990-11-21 | Hydrostatic / magnetic bearing spindle |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04185910A JPH04185910A (en) | 1992-07-02 |
| JPH0730789B2 true JPH0730789B2 (en) | 1995-04-10 |
Family
ID=18083278
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2316998A Expired - Lifetime JPH0730789B2 (en) | 1990-11-21 | 1990-11-21 | Hydrostatic / magnetic bearing spindle |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0730789B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20140376842A1 (en) * | 2013-06-22 | 2014-12-25 | Kla-Tencor Corporation | Gas bearing assembly for an euv light source |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108547869B (en) * | 2018-05-18 | 2019-09-10 | 燕山大学 | A kind of magnetic liquid dual suspension bearing support system |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2630792B1 (en) * | 1988-04-29 | 1992-03-06 | Mecanique Magnetique Sa | AUXILIARY BEARING WITH GRAPHITE STATOR FOR ROTATING SHAFT MOUNTED ON MAGNETIC BEARINGS |
-
1990
- 1990-11-21 JP JP2316998A patent/JPH0730789B2/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20140376842A1 (en) * | 2013-06-22 | 2014-12-25 | Kla-Tencor Corporation | Gas bearing assembly for an euv light source |
| US9422978B2 (en) * | 2013-06-22 | 2016-08-23 | Kla-Tencor Corporation | Gas bearing assembly for an EUV light source |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04185910A (en) | 1992-07-02 |
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| LAPS | Cancellation because of no payment of annual fees |