JP3431219B2 - Spindle device of machine tool - Google Patents
Spindle device of machine toolInfo
- Publication number
- JP3431219B2 JP3431219B2 JP19565993A JP19565993A JP3431219B2 JP 3431219 B2 JP3431219 B2 JP 3431219B2 JP 19565993 A JP19565993 A JP 19565993A JP 19565993 A JP19565993 A JP 19565993A JP 3431219 B2 JP3431219 B2 JP 3431219B2
- Authority
- JP
- Japan
- Prior art keywords
- main shaft
- spindle
- machine tool
- air bearing
- spindle device
- 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 - Fee Related
Links
Description
【発明の詳細な説明】
【０００１】
【産業上の利用分野】本発明は、工作機械の主軸装置に
かかり、特に、主軸を高速回転させるのに好適な主軸装
置に関するものである。
【０００２】
【従来の技術】マシニングセンタなどの工作機械で、ア
ルミニウム、あるいはアルミニウム合金製のワークを効
率良く加工するため、工作機械の主軸には数万ｒｐｍの
高速回転が要求されている。
【０００３】工作機械の主軸を支持する軸受として、一
般に、回転速度が比較的遅く、高剛性を要求される場合
に転がり軸受、高速回転が要求される場合には流体軸受
が用いられている。前記流体軸受としては、通常空気軸
受が用いられている。
【０００４】空気軸受は、主軸と空気軸受の間に形成さ
れた微小な間隙に、圧縮空気を送って空気の膜を形成
し、この空気の膜で主軸と空気軸受の接触を防止するよ
うになっている。このため、前記間隙に異物が侵入した
り、主軸の回転による振動が大きくなると、主軸と空気
軸受が接触して焼き付きを起こし、主軸や空気軸受を損
傷する。
【０００５】
【発明が解決しようとする課題】しかし、主軸を５００
００ｒｐｍの高速回転にすると、その遠心力により主軸
が、図２に実線で示すように１０数μｍ膨張し、空気軸
受と主軸のすきまが減少し、焼き付きなど、空気軸受の
損傷が起りやすくなるため、空気軸受と主軸の隙間を大
きく設定し、空気流量を大きくすることにより、低速回
転時の剛性の低下を補なわなければならない。
【０００６】本発明の目的は、上記の事情に鑑み、高速
回転時における遠心力による主軸の膨張を抑え、空気軸
受の焼き付きなどの損傷を防止すると共に、各回転領域
における剛性を向上させるようにした工作機械の主軸装
置を提供することに有る。
【０００７】
【課題を解決するための手段】上記の目的を達成するた
め、本発明においては、主軸を空気軸受によって回転可
能に支持した工作機械の主軸装置において、前記主軸の
外周面の、空気軸受と対向する位置に、前記主軸の構成
材質よりも比重が小さくかつ弾性係数の大きな繊維層を
形成した。
【０００８】
【作用】そして、主軸の質量を軽くすることにより、回
転時に主軸に作用する遠心力を小さくし、さらに、縦弾
性係数の大きい繊維層で主軸の膨張を抑える。
【０００９】
【実施例】以下、本発明の一実施例を図面にしたがって
説明する。図１は、本発明の一実施例を示すもので、同
図において、１はハウジング。２はフランジで、ハウジ
ング１の一端に固定されている。３はラジアル空気軸受
で、ハウジング１に固定されている。４、５はスラスト
空気軸受で、それぞれハウジング１とフランジ２に固定
されている。６は圧縮空気の供給路で、ハウジング１お
よびフランジ２の各空気軸受３、４、５に圧縮空気を供
給する。
【００１０】７は主軸で、ラジアル空気軸受３と対向す
る外周面に、繊維層８が形成され、ハウジング１に回転
可能に支持されている。
【００１１】前記繊維層８は、たとえば、炭素繊維に合
成樹脂を含浸させ、僅かに（炭素繊維に弛みが発生しな
い程度の）張力を与えながら巻き付けた後、乾燥炉に入
れて合成樹脂を硬化させて形成する。
【００１２】炭素繊維の縦弾性係数（６×１０4ｋｇｆ
／ｍｍ2）が鋼の縦弾性係数（２．１×１０4ｋｇｆ／ｍ
ｍ2）の約３倍であり、炭素繊維の比重（２．０）が鋼
の比重（７．８）の約１／３であるから、遠心力による
主軸７の半径方向への膨張を小さくすることができる。
【００１３】このような構成にすることにより、図２に
破線で示すように、大幅に改善することができる。すな
わち、主軸の回転を５００００ｒｐｍにしたとき、従来
の主軸では、その外形が１３μｍ膨張するのに対し、本
発明の主軸７では、６μｍ以下に抑えることができる。
したがって、空気軸受と主軸の隙間を小さく設定するこ
とができ、各回転領域における主軸の剛性を向上させる
ことができる。
【００１４】上記実施例においては、炭素繊維を用いた
場合について説明したが、炭素繊維以外でも、炭化珪素
繊維（比重３．０、弾性係数４．３×１０4）、ボロン
繊維（比重２．５７、弾性係数４．１×１０4）、アル
ミナセラミックス繊維（比重３．８、弾性係数３．９×
１０4）等のほか、合成樹脂系の繊維など比重が小さ
く、弾性係数の大きな繊維を巻き付けることにより同様
の効果を得ることができる。
【００１５】
【発明の効果】以上述べた如く、本発明によれば、空気
軸受によって回転可能に支持された工作機械の主軸装置
において、前記主軸の外周面の、少なくとも空気軸受と
対向する位置に、比重が小さく、弾性係数の大きな繊維
を巻き付けたので、高速回転時の遠心力による主軸の膨
張を抑えることができる。したがって、空気軸受と主軸
の隙間を小さく設定することができ、各回転領域におけ
る主軸の剛性を向上させることができる。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle device of a machine tool, and more particularly to a spindle device suitable for rotating a spindle at high speed. 2. Description of the Related Art In order to efficiently process a work made of aluminum or an aluminum alloy with a machine tool such as a machining center, a spindle of the machine tool is required to rotate at a high speed of tens of thousands of rpm. As a bearing for supporting a main shaft of a machine tool, a rolling bearing is generally used when the rotation speed is relatively slow and high rigidity is required, and a fluid bearing is used when high speed rotation is required. An air bearing is usually used as the fluid bearing. The air bearing forms a film of air by sending compressed air to a minute gap formed between the main shaft and the air bearing so that the air film prevents contact between the main shaft and the air bearing. Has become. For this reason, if a foreign substance enters the gap or the vibration caused by the rotation of the main shaft increases, the main shaft and the air bearing come into contact with each other, causing seizure and damaging the main shaft and the air bearing. [0005] However, the main shaft is 500
At a high rotation speed of 00 rpm, the centrifugal force causes the main shaft to expand by more than 10 μm as shown by a solid line in FIG. In addition, the gap between the air bearing and the main shaft must be set to be large, and the air flow rate must be increased to compensate for the decrease in rigidity during low-speed rotation. In view of the above circumstances, it is an object of the present invention to suppress expansion of a main shaft due to centrifugal force during high-speed rotation, prevent damage such as seizure of an air bearing, and improve rigidity in each rotation region. Another object of the present invention is to provide a spindle device for a machine tool. [0007] [Means for Solving the Problems] To achieve the above object, in the present invention, a spindle in the spindle device of machine tool rotatably supported by the air bearing, the outer peripheral surface of the spindle, empty The configuration of the main shaft at a position facing the air bearing
A fiber layer having a lower specific gravity and a higher elastic modulus than the material was formed. By reducing the mass of the main shaft, the centrifugal force acting on the main shaft during rotation is reduced, and the expansion of the main shaft is suppressed by the fiber layer having a large longitudinal elastic modulus. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the present invention, in which 1 is a housing. Reference numeral 2 denotes a flange, which is fixed to one end of the housing 1. A radial air bearing 3 is fixed to the housing 1. Reference numerals 4 and 5 denote thrust air bearings, which are fixed to the housing 1 and the flange 2, respectively. A compressed air supply path 6 supplies compressed air to each of the air bearings 3, 4, and 5 of the housing 1 and the flange 2 . A main shaft 7 has a fiber layer 8 formed on the outer peripheral surface facing the radial air bearing 3 and is rotatably supported by the housing 1. The fiber layer 8 is formed, for example, by impregnating carbon fiber with a synthetic resin, winding the fiber while applying a slight tension (to the extent that the carbon fiber does not loosen), and then putting the synthetic resin in a drying oven to cure the synthetic resin. And formed. The longitudinal modulus of carbon fiber (6 × 10 4 kgf)
/ Mm 2 ) is the modulus of longitudinal elasticity of steel (2.1 × 10 4 kgf / m)
m 2 ) and the specific gravity of carbon fiber (2.0) is about 1/3 of the specific gravity of steel (7.8), so that the expansion of the main shaft 7 in the radial direction due to centrifugal force is small. can do. By adopting such a configuration, a great improvement can be achieved as shown by a broken line in FIG. That is, when the rotation of the main spindle is set to 50,000 rpm, the outer diameter of the conventional main spindle expands by 13 μm, whereas the outer diameter of the main spindle 7 of the present invention can be suppressed to 6 μm or less.
Therefore, the gap between the air bearing and the main shaft can be set small, and the rigidity of the main shaft in each rotation region can be improved. In the above embodiment, the case where carbon fiber was used was described. However, other than carbon fiber, silicon carbide fiber (specific gravity: 3.0, elastic coefficient: 4.3 × 10 4 ), boron fiber (specific gravity: 2.10). 57, modulus of elasticity 4.1 × 10 4 ), Al
Minaceramic fiber (specific gravity 3.8, elastic modulus 3.9 ×
In addition to 10 4 ), similar effects can be obtained by winding a fiber having a small specific gravity and a large elastic coefficient such as a synthetic resin fiber. As described above, according to the present invention, in a spindle device of a machine tool rotatably supported by an air bearing, at least a position of an outer peripheral surface of the spindle is opposed to the air bearing. Since a fiber having a small specific gravity and a large elastic modulus is wound, expansion of the main shaft due to centrifugal force during high-speed rotation can be suppressed. Therefore, the gap between the air bearing and the main shaft can be set small, and the rigidity of the main shaft in each rotation region can be improved.
【図面の簡単な説明】 【図１】本発明による主軸装置の正面断面図。 【図２】主軸の回転数と膨張量の関係を示す特性図。 【符号の説明】 ３、４、５ 空気軸受 ７ 主軸 ８ 繊維層[Brief description of the drawings] FIG. 1 is a front sectional view of a spindle device according to the present invention. FIG. 2 is a characteristic diagram showing a relationship between a rotation speed of a main shaft and an expansion amount. [Explanation of symbols] 3, 4, 5 air bearing 7 Spindle 8 Fiber layer
Claims (1)
た工作機械の主軸装置において、 前記主軸の外周面の、空気軸受と対向する位置に、前記
主軸の構成材質よりも比重が小さくかつ弾性係数の大き
な繊維層を形成したことを特徴とする工作機械の主軸装
置。In the spindle device of machine tool rotatably supported by (57) Claims: 1. A air bearing spindle, the outer peripheral surface of the main shaft, at a position opposite to the air bearing, the
A spindle device for a machine tool, wherein a fiber layer having a specific gravity smaller than that of a constituent material of the spindle and having a large elastic coefficient is formed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19565993A JP3431219B2 (en) | 1993-08-06 | 1993-08-06 | Spindle device of machine tool |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19565993A JP3431219B2 (en) | 1993-08-06 | 1993-08-06 | Spindle device of machine tool |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0751903A JPH0751903A (en) | 1995-02-28 |
| JP3431219B2 true JP3431219B2 (en) | 2003-07-28 |
Family
ID=16344859
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP19565993A Expired - Fee Related JP3431219B2 (en) | 1993-08-06 | 1993-08-06 | Spindle device of machine tool |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3431219B2 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5712839B2 (en) * | 2011-02-24 | 2015-05-07 | 日本精工株式会社 | Motor built-in spindle device |
| JP5712838B2 (en) * | 2011-07-22 | 2015-05-07 | 日本精工株式会社 | Spindle device |
| JP5712840B2 (en) * | 2011-07-22 | 2015-05-07 | 日本精工株式会社 | Motor built-in spindle device |
| EP2735392B1 (en) * | 2011-07-20 | 2016-08-03 | NSK Ltd. | Spindle device |
| JP5915068B2 (en) * | 2011-10-06 | 2016-05-11 | 日本精工株式会社 | Motor built-in spindle device |
| JP5742534B2 (en) * | 2011-07-20 | 2015-07-01 | 日本精工株式会社 | Spindle device |
| KR101456890B1 (en) * | 2013-05-20 | 2014-11-20 | 주식회사 스토닉 | Combination structure of spindle for machine tool |
-
1993
- 1993-08-06 JP JP19565993A patent/JP3431219B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0751903A (en) | 1995-02-28 |
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