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JP2005214310A - Hydrostatic air bearing spindle - Google Patents

Hydrostatic air bearing spindle Download PDF

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Publication number
JP2005214310A
JP2005214310A JP2004022335A JP2004022335A JP2005214310A JP 2005214310 A JP2005214310 A JP 2005214310A JP 2004022335 A JP2004022335 A JP 2004022335A JP 2004022335 A JP2004022335 A JP 2004022335A JP 2005214310 A JP2005214310 A JP 2005214310A
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bearing
main shaft
air
hydrostatic air
thrust
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JP4264731B2 (en
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Isato Fukuma
勇人 福間
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Yaskawa Electric Corp
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Yaskawa Electric Corp
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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
    • F16C32/06—Bearings not otherwise provided for with moving member supported by a fluid cushion formed, at least to a large extent, otherwise than by movement of the shaft, e.g. hydrostatic air-cushion bearings
    • F16C32/0681—Construction or mounting aspects of hydrostatic bearings, for exclusively rotary movement, related to the direction of load
    • F16C32/0696—Construction or mounting aspects of hydrostatic bearings, for exclusively rotary movement, related to the direction of load for both radial and axial load
    • 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
    • F16C32/06—Bearings not otherwise provided for with moving member supported by a fluid cushion formed, at least to a large extent, otherwise than by movement of the shaft, e.g. hydrostatic air-cushion bearings
    • F16C32/0603—Bearings not otherwise provided for with moving member supported by a fluid cushion formed, at least to a large extent, otherwise than by movement of the shaft, e.g. hydrostatic air-cushion bearings supported by a gas cushion, e.g. an air cushion

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

Abstract

【課題】負荷側の静圧空気ジャーナル軸受に給気した圧縮空気による主軸へのスラスト方向の負荷を極力小さくし、同時に、反負荷側の静圧空気スラスト軸受の軸受性能の低下を抑制でき、スラスト方向の振れ精度の高い静圧空気軸受スピンドルを提供する。
【解決手段】主軸２を支持する静圧空気ジャーナル軸受３、４及び静圧空気スラスト軸受５、６を備えた静圧空気軸受スピンドルにおいて、主軸２は、静圧空気ジャーナル軸受の主軸軸受部２ｂとスラスト板２ａの間に主軸軸受部２ｂより小径の段付部２ｃを形成してあり、静圧空気スラストｖ軸受５の反負荷側には、略Ｌ字状の突起部５ａを段付部２ｃと対向配置すると共に、突起部５ａの内径を主軸軸受部２ｂの軸径より小さくし、主軸軸受部２ｂの段差面２ｄと突起部５ａの先端との間の排気隙間１８を微小とし、突起部５ａの先端の外周と静圧空気スラスト軸受５との間の隙間５ｂを第３排気通路１５に連通させた。
【選択図】図１[PROBLEMS] To reduce the load in the thrust direction on the main shaft due to compressed air supplied to a hydrostatic air journal bearing on the load side as much as possible, and at the same time, suppress the deterioration of the bearing performance of the hydrostatic air thrust bearing on the anti-load side, To provide a hydrostatic air bearing spindle with high runout accuracy in the thrust direction.
In a hydrostatic air bearing spindle including hydrostatic air journal bearings (3, 4) and hydrostatic air thrust bearings (5, 6) for supporting a main shaft (2), the main shaft (2) is a main shaft bearing portion (2b) of the hydrostatic air journal bearing. And a thrust plate 2a, a stepped portion 2c having a diameter smaller than that of the main shaft bearing portion 2b is formed, and a substantially L-shaped protruding portion 5a is provided on the opposite side of the hydrostatic air thrust v bearing 5 as a stepped portion. 2c, the projecting portion 5a has an inner diameter smaller than that of the main shaft bearing portion 2b, and the exhaust gap 18 between the stepped surface 2d of the main shaft bearing portion 2b and the tip of the projecting portion 5a is made minute. A gap 5 b between the outer periphery of the tip of the portion 5 a and the static pressure air thrust bearing 5 was communicated with the third exhaust passage 15.
[Selection] Figure 1

Description

本発明は、例えば、精密加工機などの高精度回転スピンドルに適し、主軸と軸受間の軸受隙間に圧縮空気を供給することによって主軸を非接触状態で支持する静圧空気軸受スピンドルに関する。   The present invention relates to a hydrostatic air bearing spindle that is suitable for a high-precision rotary spindle such as a precision processing machine and supports a main shaft in a non-contact state by supplying compressed air to a bearing gap between the main shaft and the bearing.

従来、主軸と軸受間に設けた微小な軸受隙間に給気ノズルから圧縮空気を供給することにより、主軸を非接触支持する構成の静圧空気軸受スピンドルは、図３に示すようになっている。なお、図３は従来の静圧空気軸受スピンドルの上半分を示した側断面図である。
図３において、１はハウジング、２は主軸、２ａはスラスト板、２ｂは主軸軸受部、３は反負荷側の静圧空気ジャーナル軸受、４は負荷側の静圧空気ジャーナル軸受、５は反負荷側の静圧空気スラスト軸受、６は負荷側の静圧空気スラスト軸受、７はスペーサ、８は圧縮空気供給路、９はモータ、９ａはモータロータ、９ｂはモータステータ、１０はスリーブ、１１、１２は給気ノズル、１３は第１排気通路、１４は第２排気通路、１５は第３排気通路、１６は第４排気通路、１７は負荷側静圧空気スラスト軸受６とスラスト板２ａ間の負荷側隙間、１９はハウジング蓋部である。静圧空気軸受スピンドルは、基本的にはハウジング１内に収納した主軸２と、主軸２のラジアル方向を支持する２個の静圧空気ジャーナル軸受３、４と、主軸２の負荷側に設けたスラスト板２ａの径方向に設けてなるスペーサ７の両側を挟み込むように配置され、主軸２のスラスト方向を支持する両面対向形の静圧空気スラスト軸受５、６とで構成されている。また、静圧空気ジャーナル軸受３、４には、ハウジング１に設けた圧縮空気供給路８と連通する給気ノズル１２が設けられ、静圧空気スラスト軸受５、６には、同様に圧縮空気供給路８と連通する給気ノズル１１が設けられている。また、主軸２の反負荷側端部にはモータロータ９ａが取り付けられると共に、ハウジング１にはスリーブ１０を介してモータステータ９ｂが取り付けられ、両者によりモータ９を構成する。
次に動作を説明する。
静圧空気軸受スピンドルにおいて、給気ノズル１１、１２を介して軸受隙間に圧縮空気を供給することにより、主軸２がラジアル方向およびスラスト方向に対して非接触で支持される。圧縮空気供給路８に供給された圧縮空気は、負荷側では第３排気通路１５、第４排気通路１６および負荷側隙間１７から主軸２の外部へ排気されると共に、反負荷側では第１排気通路１３から第２排気通路１４を経由して主軸２の外部へ排気される。
このように、主軸２は軸受により非接触で支持された状態で、モータ９によって直接駆動される（例えば、特許文献１参照）。
特開２００１−３０４２５９号公報（第５−６頁、図１） Conventionally, a hydrostatic air bearing spindle configured to support a main shaft in a non-contact manner by supplying compressed air from a supply nozzle to a minute bearing gap provided between the main shaft and the bearing is as shown in FIG. . FIG. 3 is a side sectional view showing the upper half of a conventional hydrostatic air bearing spindle.
In FIG. 3, 1 is a housing, 2 is a main shaft, 2a is a thrust plate, 2b is a main shaft bearing portion, 3 is an anti-load side hydrostatic air journal bearing, 4 is a load-side hydrostatic air journal bearing, and 5 is an anti-load. Side hydrostatic air thrust bearing, 6 is a load side hydrostatic air thrust bearing, 7 is a spacer, 8 is a compressed air supply path, 9 is a motor, 9a is a motor rotor, 9b is a motor stator, 10 is a sleeve, 11, 12 Is an air supply nozzle, 13 is a first exhaust passage, 14 is a second exhaust passage, 15 is a third exhaust passage, 16 is a fourth exhaust passage, and 17 is a load between the load-side static pressure air thrust bearing 6 and the thrust plate 2a. A side gap 19 is a housing lid. The hydrostatic air bearing spindle is basically provided on the load side of the main shaft 2, the main shaft 2 housed in the housing 1, the two hydrostatic air journal bearings 3 and 4 that support the radial direction of the main shaft 2. It is arranged so as to sandwich both sides of the spacer 7 provided in the radial direction of the thrust plate 2a, and is composed of double-sided opposed-type hydrostatic air thrust bearings 5 and 6 that support the thrust direction of the main shaft 2. The hydrostatic air journal bearings 3 and 4 are provided with an air supply nozzle 12 which communicates with the compressed air supply passage 8 provided in the housing 1. The hydrostatic air thrust bearings 5 and 6 are similarly supplied with compressed air. An air supply nozzle 11 communicating with the passage 8 is provided. A motor rotor 9 a is attached to the opposite end of the main shaft 2, and a motor stator 9 b is attached to the housing 1 via a sleeve 10.
Next, the operation will be described.
In the hydrostatic air bearing spindle, by supplying compressed air to the bearing gap through the air supply nozzles 11 and 12, the main shaft 2 is supported in a non-contact manner in the radial direction and the thrust direction. The compressed air supplied to the compressed air supply path 8 is exhausted from the third exhaust passage 15, the fourth exhaust passage 16 and the load side gap 17 to the outside of the main shaft 2 on the load side, and the first exhaust on the non-load side. The air is exhausted from the passage 13 to the outside of the main shaft 2 via the second exhaust passage 14.
Thus, the main shaft 2 is directly driven by the motor 9 while being supported in a non-contact manner by the bearing (see, for example, Patent Document 1).
JP 2001-304259 A (page 5-6, FIG. 1)

従来の静圧空気軸受スピンドルにおいて、負荷側静圧空気ジャーナル軸受４に給気した圧縮空気の一部は、負荷側静圧空気ジャーナル軸受４と主軸軸受部２ｂ間の軸受隙間を通過した後、空気の流れが９０度変わるようにスラスト板２ａと反負荷側静圧空気スラスト軸受５間の軸受隙間を経由して、第４排気通路１６から排気される。しかしながら、空気の流れが９０度変わる際に高圧の空気がスラスト板２ａに衝突し、このスラスト板２ａに対する空気流の衝突による衝撃が負荷となり、主軸２にスラスト方向の振れが発生するという問題があった。
また、スラスト板２ａと反負荷側静圧空気スラスト軸受５間の軸受隙間を通過する空気は、反負荷側静圧空気スラスト軸受５の給気部と交差するため、反負荷側静圧空気スラスト軸受５の気流を乱し、軸受性能を低下させるという問題もあった。その結果、スラスト方向の振れ精度が低下し、主軸２に負荷を取り付けて加工などを行う場合、加工精度に影響を及ぼすという問題が生じた。
本発明は上記問題を解決するためになされたものであり、負荷側静圧空気ジャーナル軸受に給気した圧縮空気による主軸へのスラスト方向の負荷を極力小さくすることができ、同時に、反負荷側静圧空気スラスト軸受の給気部と交差する空気を極力少なくすることができ、スラスト方向の振れ精度の高い静圧空気軸受スピンドルを提供することを目的とする。 In the conventional hydrostatic air bearing spindle, after a part of the compressed air supplied to the load-side hydrostatic air journal bearing 4 passes through the bearing gap between the load-side hydrostatic air journal bearing 4 and the main shaft bearing portion 2b, The air is exhausted from the fourth exhaust passage 16 via the bearing gap between the thrust plate 2a and the anti-load side static pressure air thrust bearing 5 so that the air flow changes by 90 degrees. However, when the air flow changes by 90 degrees, the high-pressure air collides with the thrust plate 2a, and the impact due to the collision of the air flow against the thrust plate 2a becomes a load, causing the main shaft 2 to shake in the thrust direction. there were.
Further, since the air passing through the bearing gap between the thrust plate 2a and the anti-load side static pressure air thrust bearing 5 intersects the air supply portion of the anti-load side static pressure air thrust bearing 5, the anti-load side static pressure air thrust There was also a problem that the airflow of the bearing 5 was disturbed and the bearing performance was deteriorated. As a result, the runout accuracy in the thrust direction is lowered, and when machining is performed with a load attached to the main shaft 2, there is a problem that the machining accuracy is affected.
The present invention has been made to solve the above problems, and can reduce the load in the thrust direction to the main shaft due to the compressed air supplied to the load-side hydrostatic air journal bearing as much as possible. An object of the present invention is to provide a hydrostatic air bearing spindle that can reduce the air intersecting with the air supply portion of the hydrostatic thrust bearing as much as possible and has high deflection accuracy in the thrust direction.

上記問題を解決するため、本発明は、次のように構成したのである。
請求項１に記載の発明は、ハウジングに収納された主軸と、前記主軸のラジアル方向を支持する静圧空気ジャーナル軸受と、前記主軸のスラスト方向を支持する静圧空気スラスト軸受と、前記静圧空気ジャーナル軸受の反負荷側に設けられ、前記静圧空気ジャーナル軸受の排気を前記主軸の外部へ導くための第１排気通路と、前記ハウジングに設けられ、前記第１排気通路の排気を前記主軸の外部へ導くための第２排気通路と、前記静圧空気スラスト軸受の反負荷側に設けられ、前記静圧空気ジャーナル軸受の排気を前記主軸の外部へ導くための第３排気通路と、前記静圧空気スラスト軸受の負荷側と反負荷側間のスペーサに設けられ、前記静圧空気ジャーナル軸受および前記スラスト軸受の排気を前記主軸の外部へ導くための第４排気通路と、前記主軸の反負荷側端部に取り付けたモータロータと、前記ハウジングにスリーブを介して取り付けたモータステータを備えた静圧空気軸受スピンドルにおいて、前記主軸は、前記静圧空気ジャーナル軸受の軸受面となる主軸軸受部と前記静圧空気スラスト軸受の軸受面となる前記スラスト板との間に該主軸軸受部の軸径より小さい軸径を有する段付部を形成してあり、前記静圧空気スラスト軸受の反負荷側には、前記主軸軸受部側に先端が突出した形状を有する略Ｌ字状の突起部を前記段付部と対向するように設けると共に、前記突起部の内径を前記主軸軸受部の軸径より小さくしてあり、前記主軸軸受部の段差面と前記突起部の先端との間に形成される排気隙間を微小としてあり、前記突起部の先端の外周と前記反負荷の側静圧空気スラスト軸受との間の隙間を前記第３排気通路に連通させるようにしたものである。
また、請求項２に記載の発明は、請求項１記載の静圧空気軸受スピンドルにおいて、前記突起部の先端を前記負荷側静圧空気ジャーナル軸受からの空気が前記第３排気通路へ流れやすくなるようにテーパ形状としたものである。 In order to solve the above problem, the present invention is configured as follows.
The invention according to claim 1 includes a main shaft housed in a housing, a hydrostatic air journal bearing that supports a radial direction of the main shaft, a hydrostatic air thrust bearing that supports a thrust direction of the main shaft, and the static pressure. A first exhaust passage provided on a non-load side of the air journal bearing for guiding the exhaust of the hydrostatic air journal bearing to the outside of the main shaft; and provided in the housing; the exhaust of the first exhaust passage is supplied to the main shaft A second exhaust passage for leading the outside of the hydrostatic air thrust bearing, a third exhaust passage for guiding the exhaust of the hydrostatic air journal bearing to the outside of the main shaft, A fourth exhaust passage provided in a spacer between the load side and the anti-load side of the hydrostatic air thrust bearing for guiding the exhaust of the hydrostatic air journal bearing and the thrust bearing to the outside of the main shaft; A hydrostatic air bearing spindle comprising a motor rotor attached to the opposite end of the main shaft and a motor stator attached to the housing via a sleeve, wherein the main shaft is a bearing surface of the hydrostatic air journal bearing. A stepped portion having a shaft diameter smaller than the shaft diameter of the main shaft bearing portion is formed between the main shaft bearing portion and the thrust plate serving as a bearing surface of the hydrostatic air thrust bearing; A substantially L-shaped projecting portion having a shape with a tip projecting toward the main shaft bearing portion side is provided on the opposite load side of the bearing so as to face the stepped portion, and the inner diameter of the projecting portion is set to the main shaft bearing. The exhaust gap formed between the stepped surface of the main shaft bearing portion and the tip of the projection is made minute, the outer periphery of the tip of the projection and the side opposite to the anti-load Static pressure air The gap between the thrust bearing is obtained so as to communicated with the third exhaust passage.
According to a second aspect of the present invention, in the hydrostatic air bearing spindle according to the first aspect, air from the load-side hydrostatic air journal bearing tends to flow to the third exhaust passage at the tip of the protrusion. In this way, the shape is tapered.

請求項１および請求項２に記載の発明によると、スラスト板に衝突する空気および反負荷側静圧空気スラスト軸受の給気部と交差する空気は極めて少なくなるため、主軸へのスラスト方向の負荷を大幅に軽減することができ、同時に、反負荷側静圧空気スラスト軸受の軸受性能の低下を抑制することができるため、スラスト方向の振れ精度の高い静圧空気軸受スピンドルを提供することができる。   According to the first and second aspects of the present invention, since the air colliding with the thrust plate and the air intersecting with the air supply portion of the anti-load side static pressure air thrust bearing are extremely reduced, the load in the thrust direction on the main shaft is reduced. Can be significantly reduced, and at the same time, it is possible to suppress a decrease in bearing performance of the anti-load side static pressure air thrust bearing. Therefore, it is possible to provide a hydrostatic air bearing spindle with high runout accuracy in the thrust direction. .

以下、本発明の実施の形態について図を参照して説明する。   Hereinafter, embodiments of the present invention will be described with reference to the drawings.

図１は、本発明の第１実施例による静圧空気軸受スピンドルの上半分を示した側断面図である。なお、本発明の構成要素が従来技術と同じものついてはその説明を省略し、異なる点について説明する。
図１において、２ｃは段付部、２ｄは段差面、５ａは突起部、５ｂは隙間、１８は排気隙間、Ｄ１主軸軸受部の軸径、Ｄ２は段付部の軸径である。
本発明が従来技術と異なる点は以下のとおりである。
すなわち、主軸２は、静圧空気ジャーナル軸受の軸受面となる主軸軸受部２ｂと前記静圧空気スラスト軸受５、６の軸受面となるスラスト板２ａとの間に主軸軸受部２ｂの軸径Ｄ１より小さい軸径Ｄ２を有する段付部２ｃを形成してあり、静圧空気スラスト軸受５の反負荷側には、主軸軸受部２ｂ側に先端が突出した形状を有する略Ｌ字状の突起部５ａを段付部２ｃと対向するように設けると共に、突起部５ａの内径を主軸軸受部２ｂの軸径より小さくしてあり、主軸軸受部２ｂの段差面２ｄと突起部５ａの先端との間に形成される排気隙間１８を微小としてあり、突起部５ａの先端の外周と反負荷側の静圧空気スラスト軸受５との間の隙間５ｂを第３排気通路１５に連通させるようにした点である。
ここで、反負荷側静圧空気スラスト軸受５は２個以上に分割可能な部品で構成し、各部品の分割面における空気の流路の周囲はＯリングなどでシールを行い空気の漏れを防止するようになっている。また、組立は、モータ９、静圧空気ジャーナル軸受３、４を取り付けたハウジング１に主軸２を挿入し、反負荷側静圧空気スラスト軸受５を構成し、その後、スペーサ７、負荷側静圧空気スラスト軸受６を取り付けるという手順で行う。 FIG. 1 is a side sectional view showing an upper half of a hydrostatic air bearing spindle according to a first embodiment of the present invention. Note that the description of the same constituent elements of the present invention as those of the prior art will be omitted, and different points will be described.
In FIG. 1, 2c is a stepped portion, 2d is a stepped surface, 5a is a protruding portion, 5b is a gap, 18 is an exhaust gap, the shaft diameter of the D1 main shaft bearing portion, and D2 is the shaft diameter of the stepped portion.
The present invention is different from the prior art as follows.
That is, the main shaft 2 has a shaft diameter D1 of the main shaft bearing portion 2b between the main shaft bearing portion 2b serving as the bearing surface of the hydrostatic air journal bearing and the thrust plate 2a serving as the bearing surface of the hydrostatic air thrust bearings 5 and 6. A stepped portion 2c having a smaller shaft diameter D2 is formed, and a substantially L-shaped protruding portion having a shape in which the tip protrudes toward the main shaft bearing portion 2b on the opposite side of the hydrostatic air thrust bearing 5 5a is provided so as to face the stepped portion 2c, and the inner diameter of the protrusion 5a is made smaller than the shaft diameter of the main shaft bearing portion 2b, between the stepped surface 2d of the main shaft bearing portion 2b and the tip of the protrusion 5a. The exhaust gap 18 formed on the outer periphery of the projection 5a is very small, and the gap 5b between the outer periphery of the tip of the projection 5a and the anti-load-side static pressure air thrust bearing 5 is communicated with the third exhaust passage 15. is there.
Here, the anti-load side static pressure air thrust bearing 5 is composed of parts that can be divided into two or more parts. The periphery of the air flow path on the divided surface of each part is sealed with an O-ring to prevent air leakage. It is supposed to do. In addition, the assembly is performed by inserting the main shaft 2 into the housing 1 to which the motor 9 and the static pressure air journal bearings 3 and 4 are attached to form the anti-load side static pressure air thrust bearing 5, and then the spacer 7 and the load side static pressure. The procedure is to attach the air thrust bearing 6.

次に動作を説明する。
負荷側静圧空気ジャーナル軸受４に給気した圧縮空気のうち、負荷側に流れる空気は、主軸２の段差面２ｄと突起部５ａ間の排気隙間１８が微小のため、排気隙間１８を通過する空気、すなわちスラスト板２ａに衝突する空気および反負荷側の静圧空気スラスト軸受５の給気部と交差する空気は極めて少なくなり、大部分の空気が起部５ａの先端の外周と反負荷側の静圧空気スラスト軸受５との間にある隙間５ｂから第３排気通路１５の方へ向かうという経路で主軸２の外部へ排気される。
第１実施例は上記構成にしたので、負荷側の静圧空気ジャーナル軸受４に給気した圧縮空気による主軸２へのスラスト方向の負荷を大幅に軽減することができると共に、また、反負荷側静圧空気スラスト軸受５の軸受性能の低下を抑制することができる。その結果、スラスト方向の振れ精度の高い静圧空気軸受スピンドルを提供することができる。 Next, the operation will be described.
Of the compressed air supplied to the load-side hydrostatic air journal bearing 4, the air flowing to the load side passes through the exhaust gap 18 because the exhaust gap 18 between the stepped surface 2 d of the main shaft 2 and the projection 5 a is very small. Air, that is, air that collides with the thrust plate 2a and air that intersects the air supply portion of the static pressure air thrust bearing 5 on the anti-load side is extremely small, and most of the air is on the outer periphery of the tip of the start portion 5a and the anti-load side. The air is exhausted to the outside of the main shaft 2 through a path from the gap 5b between the hydrostatic air thrust bearing 5 and the third exhaust passage 15.
Since the first embodiment has the above-described configuration, it is possible to greatly reduce the load in the thrust direction on the main shaft 2 due to the compressed air supplied to the hydrostatic air journal bearing 4 on the load side. A decrease in bearing performance of the hydrostatic air thrust bearing 5 can be suppressed. As a result, it is possible to provide a hydrostatic air bearing spindle with high deflection accuracy in the thrust direction.

図２は本発明の第２実施例による静圧空気軸受スピンドルの上半分を示した側断面図である。
図２において、５ｃは突起部の外周である。
第２実施例が第１実施例と異なる点は、突起部５ａの先端を負荷側静圧空気ジャーナル軸受４からの空気が第３排気通路１５へ流れやすくなるようにするためテーパ形状とした点である。 FIG. 2 is a side sectional view showing an upper half of a hydrostatic air bearing spindle according to a second embodiment of the present invention.
In FIG. 2, 5c is the outer periphery of the protrusion.
The second embodiment differs from the first embodiment in that the tip of the protrusion 5a is tapered so that air from the load-side hydrostatic air journal bearing 4 can easily flow to the third exhaust passage 15. It is.

次に動作を説明する。
負荷側静圧空気ジャーナル軸受４に給気した圧縮空気のうち、負荷側に流れる空気は、主軸２の段差面２ｅと突起部５ａ間の排気隙間１８が微小であり、さらに、突起部５ａの外周５ｃが傾斜をつけたテーパ状で空気が第３排気通路１５へ流れやすくなっているため、排気隙間１８を通過する空気、すなわちスラスト板２ａに衝突する空気および反負荷側静圧空気スラスト軸受５の給気部と交差する空気は極めて少なくなり、大部分が反負荷側静圧空気スラスト軸受５の隙間５ｂから第３排気通路１５という経路で主軸２の外部へ排気される。
第２実施例は上記構成にしたので、負荷側静圧空気ジャーナル軸受４に給気した圧縮空気による主軸２へのスラスト方向の負荷を大幅に軽減することができると共に、また、反負荷側静圧空気スラスト軸受５の軸受性能の低下を抑制することができる。その結果、スラスト方向の振れ精度の高い静圧空気軸受スピンドルを提供することができる。 Next, the operation will be described.
Of the compressed air supplied to the load-side hydrostatic air journal bearing 4, the air flowing to the load side has a very small exhaust gap 18 between the stepped surface 2e of the main shaft 2 and the protrusion 5a. Since the outer periphery 5c is tapered and air easily flows into the third exhaust passage 15, the air passing through the exhaust gap 18, that is, the air colliding with the thrust plate 2a and the anti-load side static pressure air thrust bearing The air intersecting with the air supply section 5 is extremely small, and most of the air is exhausted to the outside of the main shaft 2 through the clearance 5b of the anti-load side static pressure air thrust bearing 5 through a path called the third exhaust passage 15.
Since the second embodiment has the above-described configuration, the load in the thrust direction on the main shaft 2 due to the compressed air supplied to the load-side hydrostatic air journal bearing 4 can be greatly reduced, and the anti-load-side static air can be reduced. A decrease in bearing performance of the compressed air thrust bearing 5 can be suppressed. As a result, it is possible to provide a hydrostatic air bearing spindle with high deflection accuracy in the thrust direction.

静圧空気軸受スピンドルは静圧空気軸受の剛性を向上させることによって、回転振れ精度の高精度化が期待でき、例えば、ハードディスク検査装置、レーザスキャナ用ポリゴンミラー、真円度測定機などの用途にも適用できる。   The hydrostatic air bearing spindle can be expected to improve the rotational runout accuracy by improving the rigidity of the hydrostatic air bearing. For example, it can be used for hard disk inspection devices, polygon mirrors for laser scanners, roundness measuring machines, etc. Is also applicable.

本発明の第１実施例を示す静圧空気軸受スピンドルの上半分を示した側断面図1 is a side sectional view showing an upper half of a hydrostatic air bearing spindle according to a first embodiment of the present invention. 本発明の第２実施例を示す静圧空気軸受スピンドルの上半分を示した側断面図Side sectional view showing the upper half of a hydrostatic air bearing spindle showing a second embodiment of the present invention 従来の静圧空気軸受スピンドルの上半分を示した側断面図Side sectional view showing the upper half of a conventional hydrostatic air bearing spindle

符号の説明Explanation of symbols

１ ハウジング
２ 主軸
２ａ スラスト板
２ｂ 主軸軸受部
２ｃ 段付部
２ｄ 段差面
３ 静圧空気ジャーナル軸受（反負荷側）
４ 静圧空気ジャーナル軸受（負荷側）
５ 静圧空気スラスト軸受（反負荷側）
５ａ 突起部
５ｂ 隙間
５ｃ 突起部の外周
６ 静圧空気スラスト軸受（反負荷側）
７ スペーサ
８ 圧縮空気供給路
９ モータ
９ａ モータロータ
９ｂ モータステータ
１０ スリーブ
１１、１２ 給気ノズル
１３ 第１排気通路
１４ 第２排気通路
１５ 第３排気通路
１６ 第４排気通路
１７ 負荷側隙間
１８ 排気隙間
１９ ハウジング蓋部
Ｄ１ 主軸軸受部の軸径
Ｄ２ 段付部の軸径 1 Housing 2 Main shaft 2a Thrust plate 2b Main shaft bearing portion 2c Stepped portion 2d Step surface 3 Hydrostatic air journal bearing (anti-load side)
4 Hydrostatic journal bearing (load side)
5 Hydrostatic air thrust bearing (anti-load side)
5a Protruding part 5b Clearance 5c Outer periphery 6 Hydrostatic air thrust bearing (anti-load side)
7 Spacer 8 Compressed air supply path 9 Motor 9a Motor rotor 9b Motor stator 10 Sleeves 11 and 12 Air supply nozzle 13 First exhaust passage 14 Second exhaust passage 15 Third exhaust passage 16 Fourth exhaust passage 17 Load side clearance 18 Exhaust clearance 19 Housing lid part D1 Shaft diameter of main shaft bearing part D2 Shaft diameter of stepped part

Claims (2)

ハウジングに収納された主軸と、前記主軸のラジアル方向を支持する静圧空気ジャーナル軸受と、前記主軸のスラスト方向を支持する静圧空気スラスト軸受と、前記静圧空気ジャーナル軸受の反負荷側に設けられ、前記静圧空気ジャーナル軸受の排気を前記主軸の外部へ導くための第１排気通路と、前記ハウジングに設けられ、前記第１排気通路の排気を前記主軸の外部へ導くための第２排気通路と、前記静圧空気スラスト軸受の反負荷側に設けられ、前記静圧空気ジャーナル軸受の排気を前記主軸の外部へ導くための第３排気通路と、前記静圧空気スラスト軸受の負荷側と反負荷側間のスペーサに設けられ、前記静圧空気ジャーナル軸受および前記スラスト軸受の排気を前記主軸の外部へ導くための第４排気通路と、前記主軸の反負荷側端部に取り付けたモータロータと、前記ハウジングにスリーブを介して取り付けたモータステータを備えた静圧空気軸受スピンドルにおいて、
前記主軸は、前記静圧空気ジャーナル軸受の軸受面となる主軸軸受部と前記静圧空気スラスト軸受の軸受面となるスラスト板との間に該主軸軸受部の軸径より小さい軸径を有する段付部を形成してあり、
前記静圧空気スラスト軸受の反負荷側には、前記主軸軸受部側に先端が突出した形状を有する略Ｌ字状の突起部を前記段付部と対向するように設けると共に、前記突起部の内径を前記主軸軸受部の軸径より小さくしてあり、
前記主軸軸受部の段差面と前記突起部の先端との間に形成される排気隙間を微小としてあり、
前記突起部の先端の外周と前記反負荷側の静圧空気スラスト軸受との間の隙間を前記第３排気通路に連通させたことを特徴とする静圧空気軸受スピンドル。 A main shaft housed in a housing, a hydrostatic air journal bearing that supports a radial direction of the main shaft, a hydrostatic air thrust bearing that supports a thrust direction of the main shaft, and a non-load side of the hydrostatic air journal bearing A first exhaust passage for guiding the exhaust of the hydrostatic air journal bearing to the outside of the main shaft, and a second exhaust for guiding the exhaust of the first exhaust passage to the outside of the main shaft. A passage, a third exhaust passage provided on a non-load side of the hydrostatic air thrust bearing, for guiding exhaust of the hydrostatic air journal bearing to the outside of the main shaft, and a load side of the hydrostatic air thrust bearing; A fourth exhaust passage provided in a spacer between the anti-load sides, for guiding the exhaust of the hydrostatic air journal bearing and the thrust bearing to the outside of the main shaft, and an anti-load side end of the main shaft In static pressure air bearing spindle comprising a motor rotor mounted, a motor stator mounted through the sleeve to the housing,
The main shaft has a shaft diameter smaller than the shaft diameter of the main shaft bearing portion between a main shaft bearing portion serving as a bearing surface of the hydrostatic air journal bearing and a thrust plate serving as a bearing surface of the hydrostatic air thrust bearing. The appendix is formed,
On the anti-load side of the hydrostatic air thrust bearing, a substantially L-shaped projecting portion having a shape with a tip projecting toward the main shaft bearing portion side is provided so as to face the stepped portion. The inner diameter is smaller than the shaft diameter of the main shaft bearing portion,
The exhaust gap formed between the stepped surface of the spindle bearing portion and the tip of the projection is made minute,
A hydrostatic air bearing spindle, wherein a clearance between the outer periphery of the tip of the protrusion and the anti-load-side hydrostatic air thrust bearing is communicated with the third exhaust passage. 前記突起部の先端を前記負荷側静圧空気ジャーナル軸受からの空気が前記第３排気通路へ流れやすくなるようにテーパ形状としたことを特徴とする請求項１記載の静圧空気軸受スピンドル。   2. The hydrostatic air bearing spindle according to claim 1, wherein a tip of the protrusion is tapered so that air from the load-side hydrostatic air journal bearing can easily flow into the third exhaust passage. 3.
JP2004022335A 2004-01-30 2004-01-30 Hydrostatic air bearing spindle Expired - Fee Related JP4264731B2 (en)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101774031A (en) * 2010-03-03 2010-07-14 湖南大学 Ultrahigh speed precise pneumatic micro spindle unit
CN105952798A (en) * 2016-07-13 2016-09-21 重庆大学 High-precision static pressure air bearing
CN108051214A (en) * 2018-01-15 2018-05-18 佛山特博科技有限公司 A kind of foil dynamical pressure air journal bearing is performance test bed
CN111076932A (en) * 2020-01-07 2020-04-28 江苏集萃精凯高端装备技术有限公司 Test system and test method for aerostatic bearing
CN111347068A (en) * 2018-12-20 2020-06-30 财团法人金属工业研究发展中心 Auxiliary milling spindle device

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102519418A (en) * 2011-12-19 2012-06-27 西安威而信精密仪器有限公司 Heavy load bearing roundness measuring equipment

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101774031A (en) * 2010-03-03 2010-07-14 湖南大学 Ultrahigh speed precise pneumatic micro spindle unit
CN105952798A (en) * 2016-07-13 2016-09-21 重庆大学 High-precision static pressure air bearing
CN108051214A (en) * 2018-01-15 2018-05-18 佛山特博科技有限公司 A kind of foil dynamical pressure air journal bearing is performance test bed
CN111347068A (en) * 2018-12-20 2020-06-30 财团法人金属工业研究发展中心 Auxiliary milling spindle device
CN111076932A (en) * 2020-01-07 2020-04-28 江苏集萃精凯高端装备技术有限公司 Test system and test method for aerostatic bearing

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