JPH10213125A - Dynamic pressure bearing made of ceramics - Google Patents
Dynamic pressure bearing made of ceramicsInfo
- Publication number
- JPH10213125A JPH10213125A JP9015336A JP1533697A JPH10213125A JP H10213125 A JPH10213125 A JP H10213125A JP 9015336 A JP9015336 A JP 9015336A JP 1533697 A JP1533697 A JP 1533697A JP H10213125 A JPH10213125 A JP H10213125A
- Authority
- JP
- Japan
- Prior art keywords
- bearing
- main shaft
- dynamic pressure
- pressure bearing
- ceramics
- 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.)
- Granted
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
- F16C17/00—Sliding-contact bearings for exclusively rotary movement
- F16C17/02—Sliding-contact bearings for exclusively rotary movement for radial load only
- F16C17/026—Sliding-contact bearings for exclusively rotary movement for radial load only with helical grooves in the bearing surface to generate hydrodynamic pressure, e.g. herringbone grooves
-
- 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
- F16C2240/00—Specified values or numerical ranges of parameters; Relations between them
- F16C2240/40—Linear dimensions, e.g. length, radius, thickness, gap
- F16C2240/54—Surface roughness
-
- 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
- F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
- F16C33/02—Parts of sliding-contact bearings
- F16C33/04—Brasses; Bushes; Linings
- F16C33/043—Sliding surface consisting mainly of ceramics, cermets or hard carbon, e.g. diamond like carbon [DLC]
Landscapes
- Sliding-Contact Bearings (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、回転時には主軸と
軸受とが非接触となり、主軸又は軸受が回転する動圧軸
受に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrodynamic bearing in which a main shaft and a bearing are not in contact with each other during rotation, and the main shaft or the bearing rotates.
【０００２】[0002]
【従来の技術】従来より、高速回転する高精度モータに
は、高速回転時の優れた軸受性能を得るためや、低回転
ムラの発生の防止等のために、空気等の気体を媒体とし
た動圧軸受が用いられている。この動圧軸受とは、例え
ば主軸が回転する場合には、回転時に主軸が軸受面と非
接触で支持されて回転するものであり、この主軸及び軸
受の材料には、ステンレス等の金属もしくはこれらに樹
脂等のコーティングを施したものが一般的に用いられて
いる。2. Description of the Related Art Conventionally, a high-precision motor that rotates at high speed uses a gas such as air as a medium in order to obtain excellent bearing performance at high speed rotation and to prevent occurrence of unevenness in low rotation. A hydrodynamic bearing is used. The dynamic pressure bearing is, for example, when the main shaft rotates, the main shaft rotates while being supported in a non-contact manner with the bearing surface when the main shaft rotates. The material of the main shaft and the bearing may be a metal such as stainless steel or the like. In general, a resin coated with a resin or the like is generally used.
【０００３】ところが、金属製の動圧軸受では、起動時
および停止時に主軸と軸受が焼き付きを起こすことがあ
る。また、金属に樹脂をコーティングを施したもので
は、耐摩耗性に劣り動圧軸受としての寿命が短いという
問題があった。However, in the case of a metal dynamic pressure bearing, the main shaft and the bearing may seize at the time of starting and stopping. Further, when a metal is coated with a resin, there is a problem that the wear resistance is poor and the life as a dynamic pressure bearing is short.
【０００４】[0004]
【発明が解決しようとする課題】そこで、上記のような
動圧軸受の起動時および停止時の焼き付きを防止するた
めに、主軸及び軸受の両方またはどちらか一方を、焼き
付きが生じにくくしかも耐摩耗性に優れているアルミナ
を始めとするセラミックスにより構成することが行われ
ている。Therefore, in order to prevent the above-mentioned seizure at the time of starting and stopping the dynamic pressure bearing, it is difficult for the main shaft and / or the bearing to seize and to prevent wear. It has been made of ceramics such as alumina which has excellent properties.
【０００５】しかしながら、このように動圧部品にセラ
ミックスを用いた場合でも、主軸回転中に振動が発生し
たり、（仮に一方が金属である場合には）依然として焼
き付きが発生する等の問題が生じていた。つまり、振動
の問題は、主軸及び軸受の両方またはどちらか一方をセ
ラミックスとした場合にも発生し、焼き付きの問題は、
主軸をステンレス等の金属とした場合に発生することが
あった。[0005] However, even when ceramics are used for the dynamic pressure parts, there are problems such as the occurrence of vibration during rotation of the main shaft and the occurrence of seizure (if one of them is made of metal). I was In other words, the problem of vibration also occurs when both or one of the main shaft and the bearing is made of ceramics.
This may occur when the main shaft is made of metal such as stainless steel.
【０００６】本発明は、前記課題を解決するためになさ
れたものであり、動圧軸受の回転中に振動や焼き付きが
発生することがないセラミックス製動圧軸受を提供する
ことを目的とする。SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a ceramic dynamic pressure bearing which does not generate vibration or seizure during rotation of the dynamic pressure bearing.
【０００７】[0007]
【課題を解決するための手段】前記目的を達成するため
の請求項１の発明は、主軸もしくは軸受が回転する際
に、該主軸と軸受とが互いの回転面にて非接触となる動
圧軸受において、前記主軸もしくは軸受又は双方のう
ち、少なくとも前記回転面がセラミックスから構成され
るとともに、該セラミックスからなる回転面の表面粗さ
が、凹凸の平均間隔（Ｓｍ）で５〜５０μｍであること
を特徴とするセラミックス製動圧軸受を要旨とする。According to a first aspect of the present invention, there is provided a dynamic pressure control apparatus in which when a main shaft or a bearing rotates, the main shaft and the bearing come into non-contact with each other on their rotating surfaces. In the bearing, at least the rotating surface of the main shaft and / or the bearing is made of ceramics, and the surface roughness of the rotating surface made of the ceramics is 5 to 50 μm in average spacing (Sm) of irregularities. The gist of the present invention is a dynamic pressure bearing made of ceramics.
【０００８】前記セラミックスとしては、アルミナ、ジ
ルコニア、アルミナ−ジルコニア、窒化珪素、炭化珪素
等を採用できる。前記Ｓｍとは、ＪＩＳ Ｂ ０６０１
により凹凸の平均間隔を定義するものであり、具体的に
は、例えば図１に示す様に凹凸があるとすると、粗さ曲
線ｒから平均線ｍの方向に基準長さｌだけ抜取り、この
抜取り部分において一つの山及びそれに隣合う一つの谷
に対応する平均線ｍの長さの和を求め、この多数の凹凸
の間隔の算術平均値をミリメートル［ｍｍ］で表したも
のをいう。即ち、Ｓｍは、下記式（１）で表されるもの
をいう。As the ceramic, alumina, zirconia, alumina-zirconia, silicon nitride, silicon carbide and the like can be used. The Sm is JIS B 0601
Defines the average interval between the irregularities. Specifically, for example, assuming that there are irregularities as shown in FIG. 1, a standard length 1 is extracted from the roughness curve r in the direction of the average line m. The sum of the lengths of the average lines m corresponding to one peak and one valley adjacent to the peak in the portion is obtained, and the arithmetic mean value of the intervals between the many irregularities is expressed in millimeters [mm]. That is, Sm refers to one represented by the following formula (1).
【０００９】[0009]
【数１】 (Equation 1)
【００１０】請求項２の発明は、前記セラミックスから
なる回転面に、多数の空孔を有していることを特徴とす
る前記請求項１に記載のセラミックス製動圧軸受を要旨
とする。この多数の空孔は、回転面の表面に均一に分散
していることが好ましい。また、その径に関しては、あ
まり小さかったり大きかったりすることは望ましくな
く、同じ程度の径の空孔が分散していることが望まし
い。According to a second aspect of the present invention, there is provided a ceramic dynamic pressure bearing according to the first aspect, wherein the rotating surface made of the ceramic has a large number of holes. Preferably, the large number of holes are uniformly dispersed on the surface of the rotating surface. In addition, it is not desirable that the diameter is too small or large, and it is preferable that pores having the same diameter are dispersed.
【００１１】従って、セラミックスの回転面の接触面積
率としては、例えば５０〜８０％の範囲が好適である。
また、空孔の回転面における直径の平均値は、５〜２０
μｍの範囲が好適である。更に、空孔の回転面のおける
直径は、５〜１５μｍの範囲内であると好適である。Therefore, the contact area ratio of the rotating surface of the ceramic is preferably, for example, in the range of 50 to 80%.
The average value of the diameter of the hole on the rotation surface is 5 to 20.
The range of μm is preferred. Furthermore, it is preferable that the diameter of the rotation surface of the hole be in the range of 5 to 15 μm.
【００１２】請求項３の発明は、前記主軸が、前記軸受
の貫通孔内にて回転する構成であることを特徴とする前
記請求項１又は２に記載のセラミックス製動圧軸受を要
旨とする。According to a third aspect of the present invention, there is provided a ceramic dynamic pressure bearing according to the first or second aspect, wherein the main shaft rotates in a through hole of the bearing. .
【００１３】[0013]
【発明の実施の形態】セラミックス材を動圧軸受の材料
として採用する場合には、主軸と軸受のセラミックス材
の回転面における表面粗さが問題になる。つまり、一般
に研磨加工後のセラミックス表面では、研磨時の粒子脱
落により、微少な孔が存在しているが、このような孔の
数、大きさ、分布状態等が、動圧軸受の回転時の振動
や、（主軸と軸受の一方が金属である場合の）焼き付き
に大きな影響を及ぼしていると考えられる。DESCRIPTION OF THE PREFERRED EMBODIMENTS When a ceramic material is used as a material for a dynamic pressure bearing, the surface roughness of the rotating surface of the ceramic material of the main shaft and the bearing becomes a problem. In other words, generally, fine holes are present on the ceramic surface after polishing due to particles falling off during polishing, but the number, size, distribution state, etc. of such holes are affected by the rotation of the dynamic pressure bearing during rotation. It is considered that this has a great effect on vibration and seizure (when one of the main shaft and the bearing is made of metal).
【００１４】具体的には、セラミック材の回転面に径の
大きな孔（例えば直径１００μｍを超える孔）が存在し
ている場合には、例えば主軸が回転する際に、主軸と軸
受との間にある流体層に乱れが発生し、例えば主軸に振
動が発生すると考えられる。一方、セラミックス材の回
転面に存在する孔の個数が少なすぎたり、孔の径が小さ
いものが多数の場合には、主軸と軸受の回転面に凝着が
生じ易くなり、主軸等が金属で形成されている場合に
は、焼き付きが生じことがある。Specifically, when a large-diameter hole (for example, a hole having a diameter of more than 100 μm) is present on the rotating surface of the ceramic material, for example, when the main shaft rotates, the space between the main shaft and the bearing is formed. It is considered that turbulence occurs in a certain fluid layer, for example, vibration occurs in the main shaft. On the other hand, if the number of holes present on the rotating surface of the ceramic material is too small, or if there are many holes with small diameters, adhesion tends to occur on the rotating surface of the main shaft and the bearing, and the main shaft and the like are made of metal. If formed, seizure may occur.
【００１５】そこで、本発明では、セラミックスからな
る回転面の表面粗さが、凹凸の平均間隔（Ｓｍ）で５〜
５０μｍとすることにより、上述した孔の大きさや数を
適切なものとすることができるので、振動や焼き付きの
発生を防止することができる。Therefore, in the present invention, the surface roughness of the rotating surface made of ceramics is 5 to 5 in terms of the average interval (Sm) of the irregularities.
By setting the thickness to 50 μm, the size and number of the holes described above can be made appropriate, so that the occurrence of vibration and image sticking can be prevented.
【００１６】[0016]
【実施例】次に、本発明のセラミックス製動圧軸受の実
施例について説明する。 （実施例１） ａ）本実施例のセラミックス製動圧軸受は、図２（ａ）
に示す様に、例えばポリゴンミラーを回転駆動するため
のモータユニット１に使用されるものであり、空気を媒
体とした動圧軸受３である。Next, an embodiment of the ceramic dynamic pressure bearing of the present invention will be described. (Example 1) a) The dynamic pressure bearing made of ceramics of this example is shown in FIG.
As shown in FIG. 1, a dynamic pressure bearing 3 is used for a motor unit 1 for rotating a polygon mirror, for example, and uses air as a medium.
【００１７】この動圧軸受３は、円筒状の軸受５（内径
１３ｍｍ強、外径２５ｍｍ、軸方向長さ５ｍｍ）と、そ
の貫通孔７にて前記軸受５の軸方向に嵌挿された主軸９
（直径１３ｍｍ弱、長さ８ｍｍ）とからなり、主軸９は
固定されて回転せず、その周囲の軸受５側が回転する構
成となっている。尚、当然ながら、軸受５の内径と主軸
９の直径が同一では回転できないので、軸受５の内径を
１３ｍｍ強、主軸９の直径を１３ｍｍ弱として、それら
の間に僅かな隙間を持たせている。The dynamic pressure bearing 3 comprises a cylindrical bearing 5 (inner diameter 13 mm, outer diameter 25 mm, axial length 5 mm) and a main shaft inserted through the through hole 7 in the axial direction of the bearing 5. 9
(Diameter less than 13 mm, length 8 mm), the main shaft 9 is fixed and does not rotate, and the bearing 5 side around the main shaft 9 rotates. Naturally, the bearing 5 cannot rotate if the inner diameter of the bearing 5 and the diameter of the main shaft 9 are the same. Therefore, the inner diameter of the bearing 5 is more than 13 mm and the diameter of the main shaft 9 is less than 13 mm, and a slight gap is provided between them. .
【００１８】また、図２（ｂ）に示す様に、主軸９は貫
通孔７内にて偏心して配置されており、主軸９の中心軸
は貫通孔７の中心軸と例えば５μｍだけわずかにずれて
いる。よって、動圧軸受の原理により、軸受５は主軸９
と非接触にて高速回転する。尚、軸受５及び主軸９のう
ち少なくとも一方の回転面（例えば軸受５側のみ）に
は、軸受５の回転を主軸９と非接触に滑らかに行うため
に、周知の動圧溝（図示せず）が形成されている。尚、
周知の動圧溝の部分は、上述した表面粗さＳｍの対象外
である。As shown in FIG. 2B, the main shaft 9 is disposed eccentrically in the through hole 7, and the center axis of the main shaft 9 is slightly shifted from the center axis of the through hole 7 by, for example, 5 μm. ing. Therefore, according to the principle of the dynamic pressure bearing, the bearing 5 is
It rotates at high speed without contact. In order to smoothly rotate the bearing 5 in a non-contact manner with the main shaft 9, a well-known dynamic pressure groove (not shown) is provided on at least one rotating surface of the bearing 5 and the main shaft 9 (for example, only the bearing 5 side). ) Is formed. still,
The well-known dynamic pressure grooves are out of the scope of the surface roughness Sm described above.
【００１９】前記軸受５及び主軸９は、アルミナセラミ
ックからなり、各々の回転面５ａ，９ａの表面粗さＳｍ
は、５〜５０μｍの範囲に設定されている。つまり、軸
受５及び主軸９の回転面５ａ，９ａには、多数の微小な
孔（図示せず）が形成されており、この孔の大きさ及び
数により、前記表面粗さＳｍが決まる。尚、孔の径の大
きさは様々であるが、主として直径（５〜２０μｍ）の
範囲のものからなり、平均すると、１０μｍである。The bearing 5 and the main shaft 9 are made of alumina ceramic, and each of the rotating surfaces 5a, 9a has a surface roughness Sm.
Is set in the range of 5 to 50 μm. That is, a large number of minute holes (not shown) are formed in the rotating surfaces 5a, 9a of the bearing 5 and the main shaft 9, and the surface roughness Sm is determined by the size and number of these holes. The diameter of the hole varies, but is mainly in the range of a diameter (5 to 20 μm), and is 10 μm on average.
【００２０】また、本実施例では、軸受５側を回転させ
るために、図２（ａ）に示す様に、軸受５の外周に取り
付けられた環状部１１の下面側には永久磁石１３が配置
され、この永久磁石１３と対向する基台１５上には電磁
石１７が配置されている。 ｂ）上述した動圧軸受３は、下記の方法により製造する
ことができる。In this embodiment, in order to rotate the bearing 5, the permanent magnet 13 is disposed on the lower surface of the annular portion 11 mounted on the outer periphery of the bearing 5, as shown in FIG. An electromagnet 17 is arranged on the base 15 facing the permanent magnet 13. b) The above-mentioned dynamic pressure bearing 3 can be manufactured by the following method.
【００２１】アルミナからなるセラミック粉末をプレス
成形して圧粉体を焼結し、この焼結品に研磨加工を施し
て所定の寸法に仕上げる。その後、回転面５ａに動圧溝
を形成する。この動圧溝は、例えばサンドブラストやエ
ッチング等により形成する。そして、得られた動圧軸受
３をモータユニット１に組み込む。A ceramic powder made of alumina is press-molded to sinter the green compact, and this sintered product is polished to finish it to a predetermined size. Thereafter, a dynamic pressure groove is formed on the rotating surface 5a. This dynamic pressure groove is formed by, for example, sandblasting or etching. Then, the obtained dynamic pressure bearing 3 is incorporated into the motor unit 1.
【００２２】特に、軸受５及び主軸９の回転面５ａ，９
ａの表面粗さＳｍを、５〜５０μｍの範囲に設定するた
めには、使用するアルミナの粒径、成形圧力、焼結温
度、相対密度、研磨方法等を適宜選択することにより行
うことができる。例えば表面を粗くする研磨を行う場合
には、表面粗さＳｍが大きくなり、逆に表面を滑らかに
する研磨を行う場合には、表面粗さＳｍが小さくなるの
で、それらを組み合わせて、表面粗さＳｍを、５〜５０
μｍの範囲に設定することができる。In particular, the bearing 5 and the rotating surface 5a, 9 of the spindle 9
In order to set the surface roughness Sm of a in the range of 5 to 50 μm, it can be performed by appropriately selecting the particle size of alumina to be used, molding pressure, sintering temperature, relative density, polishing method and the like. . For example, when performing polishing to make the surface rough, the surface roughness Sm becomes large. Conversely, when performing polishing to make the surface smooth, the surface roughness Sm becomes small. Sm is 5-50
It can be set in the range of μm.
【００２３】上述した構成を有する本実施例の動圧軸受
３は、回転面における表面粗さＳｍが５〜５０μｍの適
度な範囲であるので、動圧軸受３の回転時の振動が極め
て少なく、また、軸受５及び主軸９がセラミックスから
構成されているので、始動時や停止時等に焼き付きが発
生することもない。In the dynamic pressure bearing 3 of the present embodiment having the above-described structure, since the surface roughness Sm on the rotating surface is in an appropriate range of 5 to 50 μm, the vibration of the dynamic pressure bearing 3 during rotation is extremely small. Further, since the bearing 5 and the main shaft 9 are made of ceramics, seizure does not occur at the time of starting or stopping.
【００２４】尚、本実施例の動圧軸受３の場合、例えば
一方の部品（軸受５又は主軸９）をステンレス等の金属
としたとしても、セラミックスからなる軸受５又は主軸
９の回転面における表面粗さＳｍが５〜５０μｍの適度
な範囲であるので、焼き付きが発生することはない。In the case of the dynamic pressure bearing 3 of this embodiment, for example, even if one of the components (the bearing 5 or the main shaft 9) is made of a metal such as stainless steel, the surface of the bearing 5 or the main shaft 9 made of ceramics on the rotating surface is required. Since the roughness Sm is in an appropriate range of 5 to 50 μm, no image sticking occurs.
【００２５】ｃ）次に、本実施例の効果を確認するため
に行った実験例について説明する。 （実験例）上述した実施例の構造のモータユニットにお
いて、軸受及び主軸の材料と回転面の表面粗さＳｍと
を、下記表１及び下記表２に示すものとした。そして、
軸受側を４００００ｒｐｍの回転数で回転させ、下記の
測定項目(1)，(2)について調べた。その結果を、同じく
下記表１及び表２に記す。C) Next, an experimental example performed to confirm the effect of the present embodiment will be described. (Experimental example) In the motor unit having the structure of the above-described embodiment, the materials of the bearing and the spindle and the surface roughness Sm of the rotating surface are as shown in Tables 1 and 2 below. And
The bearing was rotated at a rotation speed of 40000 rpm, and the following measurement items (1) and (2) were examined. The results are also shown in Tables 1 and 2 below.
【００２６】(1)振動の有無（回転中に測定） 但し、振動の検出は、非接触式のレーザ変位計（５００
００回／秒のサンプリング可能）を用いて行なう (2)焼き付きの有無（起動時及び停止時に焼き付きが発
生したか否かを確認）(1) Presence or absence of vibration (measured during rotation) However, the detection of vibration is performed by a non-contact laser displacement meter (500
(Sampling of 00 times / sec is possible.) (2) Presence or absence of burn-in (confirm whether burn-in has occurred during start-up and stop)
【００２７】[0027]
【表１】 [Table 1]
【００２８】この表１から明かな様に、実施例の試料N
o.２〜５のものは、表面粗さＳｍが、５〜５０μｍの本
発明の範囲であるので、振動が少なく金属製主軸の焼き
付きも発生しなかった。それに対して、比較例の試料N
o.１のものは、表面粗さＳｍが小さ過ぎ、振動が発生し
たので好ましくない。また、比較例の試料No.６のもの
は、表面粗さＳｍが大き過ぎ、振動及び金属製主軸の焼
き付きが発生したので好ましくない。As apparent from Table 1, the sample N of the embodiment
In the cases of o. 2 to 5, since the surface roughness Sm was within the range of the present invention of 5 to 50 µm, there was little vibration and no seizure of the metal main shaft occurred. In contrast, sample N of the comparative example
No. 1 is not preferred because the surface roughness Sm is too small and vibration occurs. The sample of Comparative Example No. 6 is not preferable because the surface roughness Sm is too large, and vibration and seizure of the metal spindle occur.
【００２９】[0029]
【表２】 [Table 2]
【００３０】この表２から明かな様に、実施例の試料N
o.８〜１１のものは、表面粗さＳｍが、５〜５０μｍの
本発明の範囲であるので、振動が少なく焼き付きも発生
しなかった。それに対して、比較例の試料No.７のもの
は、表面粗さＳｍが小さ過ぎ、振動が発生したので好ま
しくない。また、比較例の試料No.１２のものは、表面
粗さＳｍが大き過ぎ、振動が発生したので好ましくな
い。尚、この実験例では、軸受及び主軸ともにセラミッ
クスであるので、焼き付きは生じない。 （実施例２）図３に示す様に、本実施例のセラミックス
製動圧軸受２１は、円筒状の軸受２３と、その貫通孔２
５にて前記軸受２３の軸方向に嵌挿された主軸２７とか
ら構成されている。As apparent from Table 2, the sample N of the embodiment
In the case of o. 8 to 11, since the surface roughness Sm was within the range of the present invention of 5 to 50 μm, there was little vibration and no seizure occurred. On the other hand, the sample No. 7 of the comparative example is not preferable because the surface roughness Sm is too small and vibration occurs. In addition, the sample of Comparative Example No. 12 is not preferable because the surface roughness Sm is too large and vibration occurs. In this experimental example, since both the bearing and the main shaft are made of ceramics, seizure does not occur. (Embodiment 2) As shown in FIG. 3, a ceramic dynamic pressure bearing 21 according to the present embodiment has a cylindrical bearing 23 and a through hole 2
5 and a main shaft 27 fitted in the bearing 23 in the axial direction.
【００３１】本実施例では、軸受２３は固定されて回転
せず、主軸２７側が回転する構成となっており、主軸２
７は貫通孔２５内にてその中心軸よりわずかにずれて偏
心して配置されている。よって、動圧軸受の原理によ
り、主軸２７は軸受２３と非接触にて高速回転する。
尚、主軸２７及び軸受２３のうち少なくとも一方の回転
面には、周知の動圧溝（図示せず）が形成されている。In this embodiment, the bearing 23 is fixed and does not rotate, but the main shaft 27 rotates.
7 is disposed eccentrically in the through hole 25 with a slight deviation from its central axis. Therefore, the main shaft 27 rotates at a high speed without contact with the bearing 23 according to the principle of the dynamic pressure bearing.
A well-known dynamic pressure groove (not shown) is formed on at least one of the rotating surfaces of the main shaft 27 and the bearing 23.
【００３２】前記主軸２７はステンレス（ＳＵＳ ３０
４）からなり、一方、軸受２３は、アルミナセラミック
スからなり、軸受２３側の回転面２３ａの表面粗さＳｍ
は、５〜５０μｍの範囲に設定されている。本実施例の
構成によっても、前記実施例１と同様に、振動及び焼き
付きの発生を防止することができる。The main shaft 27 is made of stainless steel (SUS 30).
4), while the bearing 23 is made of alumina ceramic and has a surface roughness Sm of the rotating surface 23a on the bearing 23 side.
Is set in the range of 5 to 50 μm. According to the configuration of this embodiment, similarly to the first embodiment, the occurrence of vibration and image sticking can be prevented.
【００３３】尚、本実施例では、主軸２７を金属で構成
し、軸受２３をセラミックスで構成したが、これとは別
に、主軸２７をセラミックスで構成し、軸受２３を金属
で構成してもよく、或は、主軸２７及び軸受２３の両方
をセラミックスで構成してもよい。In the present embodiment, the main shaft 27 is made of metal and the bearing 23 is made of ceramic. Alternatively, the main shaft 27 may be made of ceramic and the bearing 23 may be made of metal. Alternatively, both the main shaft 27 and the bearing 23 may be made of ceramics.
【００３４】尚、本発明は前記実施例になんら限定され
るものではなく、本発明の要旨を逸脱しない範囲におい
て種々の態様で実施しうることはいうまでもない。It should be noted that the present invention is not limited to the above-described embodiment at all, and it goes without saying that the present invention can be carried out in various modes without departing from the gist of the present invention.
【００３５】[0035]
【発明の効果】以上詳述した様に、請求項１のセラミッ
クス製動圧軸受では、主軸又は軸受もしくは双方がセラ
ミックスから構成されるとともに、セラミックスの回転
面における表面粗さＳｍを５〜５０μｍとしたので、動
圧軸受の回転時の振動を防止することができる。また、
動圧軸受の一方の部品を金属とした場合でも、焼き付き
の発生を防止することができる。As described in detail above, in the ceramic dynamic pressure bearing of the first aspect, the main shaft or the bearing or both of them are made of ceramics, and the surface roughness Sm on the rotating surface of the ceramics is 5 to 50 μm. Therefore, vibration during rotation of the dynamic pressure bearing can be prevented. Also,
Even when one part of the dynamic pressure bearing is made of metal, the occurrence of seizure can be prevented.
【００３６】請求項２の発明では、セラミックスからな
る回転面に多数の空孔を有しているので、振動や焼き付
きの発生がなく、しかもこの空孔は研磨等により容易に
形成することができる。請求項３の発明では、例えばモ
ータユニットに使用する軸受の構成として、主軸が軸受
の貫通孔内にて回転する構成を採用できる。According to the second aspect of the present invention, since a large number of holes are formed on the rotating surface made of ceramics, vibration and seizure do not occur, and these holes can be easily formed by polishing or the like. . According to the third aspect of the present invention, for example, a configuration in which the main shaft rotates in a through hole of the bearing can be adopted as the configuration of the bearing used in the motor unit.
【図１】 表面粗さＳｍを説明する説明図である。FIG. 1 is an explanatory diagram illustrating a surface roughness Sm.
【図２】 実施例１を示し、（ａ）は動圧軸受が使用さ
れたモータユニットを一部破断して示す正面図、（ｂ）
は動圧軸受を示す平面図である。FIGS. 2A and 2B show the first embodiment, in which FIG. 2A is a front view showing a motor unit using a dynamic pressure bearing, partially cut away, and FIG.
FIG. 3 is a plan view showing a dynamic pressure bearing.
【図３】 実施例２の動圧軸受を示す斜視図である。FIG. 3 is a perspective view illustrating a dynamic pressure bearing according to a second embodiment.
１…モータユニット ３，２１…動圧軸受 ５，２３…軸受 ９，２７…主軸 DESCRIPTION OF SYMBOLS 1 ... Motor unit 3, 21 ... Dynamic pressure bearing 5, 23 ... Bearing 9, 27 ... Spindle
Claims (3)
軸と軸受とが互いの回転面にて非接触となる動圧軸受に
おいて、 前記主軸もしくは軸受又は双方のうち、少なくとも前記
回転面がセラミックスから構成されるとともに、該セラ
ミックスからなる回転面の表面粗さが、凹凸の平均間隔
（Ｓｍ）で５〜５０μｍであることを特徴とするセラミ
ックス製動圧軸受。1. A dynamic pressure bearing in which when the main shaft or the bearing rotates, the main shaft and the bearing come into non-contact with each other on the rotating surfaces, wherein at least the rotating surface of the main shaft or the bearing or both is made of ceramics. And a rotating surface made of the ceramic having a surface roughness of 5 to 50 μm in average spacing (Sm) of irregularities.
数の空孔を有していることを特徴とする前記請求項１に
記載のセラミックス製動圧軸受。2. The ceramic dynamic pressure bearing according to claim 1, wherein the rotating surface made of the ceramic has a large number of holes.
転する構成であることを特徴とする前記請求項１又は２
に記載のセラミックス製動圧軸受。3. The main shaft according to claim 1, wherein the main shaft rotates in a through hole of the bearing.
Ceramic dynamic pressure bearing described in 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP01533697A JP3782857B2 (en) | 1997-01-29 | 1997-01-29 | Ceramic hydrodynamic bearing |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP01533697A JP3782857B2 (en) | 1997-01-29 | 1997-01-29 | Ceramic hydrodynamic bearing |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2005236643A Division JP2005337508A (en) | 2005-08-17 | 2005-08-17 | Dynamic pressure bearing made of ceramics |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH10213125A true JPH10213125A (en) | 1998-08-11 |
| JP3782857B2 JP3782857B2 (en) | 2006-06-07 |
Family
ID=11885953
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP01533697A Expired - Lifetime JP3782857B2 (en) | 1997-01-29 | 1997-01-29 | Ceramic hydrodynamic bearing |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3782857B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002147459A (en) * | 2000-11-13 | 2002-05-22 | Ndc Co Ltd | Sliding bearing with overlay layer quality-improved |
| US7215508B2 (en) | 2001-03-08 | 2007-05-08 | Ngk Spark Plug Co., Ltd. | Ceramic dynamic-pressure bearing and hard disk drive using the same |
-
1997
- 1997-01-29 JP JP01533697A patent/JP3782857B2/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002147459A (en) * | 2000-11-13 | 2002-05-22 | Ndc Co Ltd | Sliding bearing with overlay layer quality-improved |
| US7215508B2 (en) | 2001-03-08 | 2007-05-08 | Ngk Spark Plug Co., Ltd. | Ceramic dynamic-pressure bearing and hard disk drive using the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3782857B2 (en) | 2006-06-07 |
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