JP2006189081A - Fluid bearing device - Google Patents
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Abstract
Description
本発明は、軸受隙間に生じる流体の潤滑膜によって回転部材を支持する流体軸受装置に関するものである。この軸受装置は、情報機器、例えばＨＤＤ等の磁気ディスク装置、ＣＤ−ＲＯＭ、ＣＤ−Ｒ／ＲＷ、ＤＶＤ−ＲＯＭ／ＲＡＭ等の光ディスク装置、ＭＤ、ＭＯ等の光磁気ディスク装置等のスピンドルモータ、レーザビームプリンタ（ＬＢＰ）のポリゴンスキャナモータ、その他の小型モータ用として好適である。 The present invention relates to a hydrodynamic bearing device in which a rotating member is supported by a lubricating film of fluid generated in a bearing gap. This bearing device is a spindle motor such as an information device, for example, a magnetic disk device such as an HDD, an optical disk device such as a CD-ROM, CD-R / RW, DVD-ROM / RAM, or a magneto-optical disk device such as MD or MO, It is suitable for polygon scanner motors of laser beam printers (LBP) and other small motors.
上記各種モータには、高回転精度の他、高速化、低コスト化、低騒音化等が求められている。これらの要求性能を決定づける構成要素の１つに当該モータのスピンドルを支持する軸受があり、近年では、上記要求性能に優れた特性を有する流体軸受の使用が検討され、あるいは実際に使用されている。 In addition to high rotational accuracy, the various motors are required to have high speed, low cost, low noise, and the like. One of the components that determine the required performance is a bearing that supports the spindle of the motor. In recent years, the use of a fluid bearing having characteristics excellent in the required performance has been studied or actually used. .
この種の流体軸受は、軸受隙間内の流体（例えば潤滑油）に動圧を発生させる動圧発生部を備えた動圧軸受と、動圧発生部を備えていない、いわゆる真円軸受（軸受断面が真円形状である軸受）とに大別される。 This type of fluid dynamic bearing includes a dynamic pressure bearing having a dynamic pressure generating section that generates dynamic pressure in a fluid (for example, lubricating oil) in a bearing gap, and a so-called circular bearing (bearing) that does not include the dynamic pressure generating section. The bearings are roughly classified into bearings having a perfect circular cross section.
例えば、ＨＤＤ等のディスク駆動装置のスピンドルモータに組み込まれる流体軸受装置では、軸部材をラジアル方向に支持するラジアル軸受部およびスラスト方向に支持するスラスト軸受部の双方を動圧軸受で構成する場合がある。この種の流体軸受装置におけるラジアル軸受部としては、例えば軸受スリーブの内周面と、これに対向する軸部材の外周面との何れか一方に、動圧発生部としての動圧溝を形成すると共に、両面間にラジアル軸受隙間を形成するものが知られている（例えば、特許文献１参照）。 For example, in a hydrodynamic bearing device incorporated in a spindle motor of a disk drive device such as an HDD, both a radial bearing portion that supports a shaft member in the radial direction and a thrust bearing portion that supports the shaft direction in a thrust direction may be configured by dynamic pressure bearings. is there. As a radial bearing part in this type of hydrodynamic bearing device, for example, a dynamic pressure groove as a dynamic pressure generating part is formed on either the inner peripheral surface of the bearing sleeve or the outer peripheral surface of the shaft member facing the bearing sleeve. In addition, there is known one that forms a radial bearing gap between both surfaces (see, for example, Patent Document 1).
また、潤滑油を上記軸受部に循環供給し、安定した軸受剛性を得る目的で、上記軸受を構成する軸受スリーブを焼結金属で形成する場合が多い。この種の軸受スリーブは、Ｃｕ粉末又はＦｅ粉末、あるいはその両者を主成分とする金属粉末を所定の形状（多くは円筒状）に圧縮成形した後、焼結することで形成される。この軸受スリーブは、内部空孔に潤滑油を含浸させた状態で使用される（例えば、特許文献２を参照）。
しかしながら、上記流体軸受装置を例えば高温雰囲気下で使用する場合、その温度によっては、あるいは潤滑油の種類によっては、軸受に供給される潤滑油の粘性が低下し、軸受剛性が不足する可能性がある。その一方で、低温雰囲気下では、潤滑油の粘性が増加し、回転時（特に回転開始時）のロストルクが上昇する恐れがある。 However, when the hydrodynamic bearing device is used in a high temperature atmosphere, for example, depending on the temperature or the type of the lubricating oil, the viscosity of the lubricating oil supplied to the bearing may decrease, and the bearing rigidity may be insufficient. is there. On the other hand, in a low temperature atmosphere, the viscosity of the lubricating oil increases, and the loss torque at the time of rotation (particularly at the start of rotation) may increase.
特に、軸方向の圧縮荷重作用下や、モーメント荷重作用下での使用を考慮して、回転支持される軸部材を例えばステンレス鋼（ＳＵＳ）などの高強度材で形成する場合、軸受スリーブを形成する材料の線膨張係数が軸部材を形成する材料の線膨張係数を上回ることも少なくない。これでは、例えば高温時には、ラジアル軸受隙間が広がってしまい、さらなる軸受剛性の低下を招く恐れがある。逆に低温時には、ラジアル軸受隙間が狭まるので、潤滑油の粘度上昇と相まって、回転時のロストルクが一層増加する恐れがある。 In particular, in consideration of use under the action of axial compressive load or moment load, when the shaft member to be rotationally supported is formed of a high-strength material such as stainless steel (SUS), a bearing sleeve is formed. Often, the linear expansion coefficient of the material to be used exceeds the linear expansion coefficient of the material forming the shaft member. In this case, for example, when the temperature is high, the radial bearing gap is widened, which may further reduce the bearing rigidity. On the other hand, at low temperatures, the radial bearing gap is narrowed, and therefore, the torque loss during rotation may be further increased in combination with an increase in the viscosity of the lubricating oil.
本発明の課題は、温度変化に伴う軸受剛性の低下を抑え、かつ回転時のロストルクを低減した流体軸受装置を提供することである。 The subject of this invention is providing the hydrodynamic bearing apparatus which suppressed the fall of the bearing rigidity accompanying a temperature change, and reduced the loss torque at the time of rotation.
前記課題を解決するため、本発明は、軸部材と、軸部材を回転支持する軸受スリーブとを備えたものにおいて、軸受スリーブが、Ｃｕ粉末と、８．０×１０-6／℃以下の線膨張係数を示す金属粉末とを含む混合金属粉末を圧縮成形した後、焼結して得られたものであることを特徴とする流体軸受装置を提供する。 In order to solve the above-described problems, the present invention includes a shaft member and a bearing sleeve that rotatably supports the shaft member. The bearing sleeve includes Cu powder and a wire of 8.0 × 10 −6 / ° C. or less. A hydrodynamic bearing device is provided which is obtained by compressing and molding a mixed metal powder containing a metal powder exhibiting an expansion coefficient and then sintering.
このように、低線膨張係数（〜８.０×１０-6／℃）を示す金属粉末をＣｕ粉末に混合したもので軸受スリーブを形成することによって、軸受スリーブの線膨張係数が、従来組成（Ｃｕ、Ｆｅ）の軸受スリーブのそれに比べて小さくなる。そのため、例えば高温時など、潤滑油の粘性が低下する場合には、ラジアル軸受隙間が広がるのを可及的に抑えることができる。また、低温時など、潤滑油の粘性が増加する場合には、ラジアル軸受隙間が狭まるのを可及的に抑えることができる。従って、高・低温雰囲気下や、温度変化の顕著な雰囲気下においても、軸受剛性の低下を極力抑えることができ、かつ回転時のロストルクを低減することができる。 Thus, by forming a bearing sleeve by mixing a metal powder exhibiting a low linear expansion coefficient (˜8.0 × 10 −6 / ° C.) with Cu powder, the linear expansion coefficient of the bearing sleeve can be reduced by the conventional composition. This is smaller than that of the (Cu, Fe) bearing sleeve. For this reason, when the viscosity of the lubricating oil decreases, for example, at a high temperature, it is possible to suppress the radial bearing gap from spreading as much as possible. In addition, when the viscosity of the lubricating oil increases, such as at low temperatures, the radial bearing gap can be minimized as much as possible. Therefore, it is possible to suppress a decrease in bearing rigidity as much as possible even in a high / low temperature atmosphere or an atmosphere where temperature change is remarkable, and to reduce loss torque during rotation.
上記線膨張係数を示す金属として、例えばＭｏやＴｗの単金属の他、Ｎｉを２５ｗｔ％以上５０ｗｔ％以下含むＦｅ−Ｎｉ合金などが使用可能である。その中でも、特にＮｉを３０ｗｔ％以上４５ｗｔ％以下含むものがより好ましく使用できる。具体的な材料として、例えばＩｎｖａｒ型（Ｆｅ−３６Ｎｉ）合金粉末、Ｓｕｐｅｒ−Ｉｎｖａｒ型（Ｆｅ−３２Ｎｉ−４Ｃｏ、Ｆｅ−３１Ｎｉ−５Ｃｏ）合金粉末、コバール型合金粉末などを挙げることができる。これらは、低線膨張特性が顕著であり、特に好適に使用可能な材料である。 As the metal exhibiting the linear expansion coefficient, for example, an Fe—Ni alloy containing Ni in an amount of 25 wt% to 50 wt% can be used in addition to a single metal of Mo or Tw. Among these, those containing 30 wt% or more and 45 wt% or less of Ni can be used more preferably. Specific examples of the material include Invar type (Fe-36Ni) alloy powder, Super-Invar type (Fe-32Ni-4Co, Fe-31Ni-5Co) alloy powder, and Kovar type alloy powder. These materials have remarkable low linear expansion characteristics and can be used particularly preferably.
これらＣｕ粉末と低線膨張金属粉末とを含む混合金属粉末としては、３０ｗｔ％以上９０ｗｔ％以下のＣｕ粉末と、１０ｗｔ％以上７０ｗｔ％以下の低線膨張金属粉末とを含むものが好ましく使用できる。これは、低線膨張金属粉末の含有量が１０ｗｔ％未満だと、低線膨張金属粉末を配合したことによる線膨張係数の低減効果が不十分となる恐れがあるためである。また、Ｃｕ粉末の含有量が３０ｗｔ％未満だと、軸受スリーブの成形性（加工性）が低下し、所要の寸法精度を確保できない、あるいは金型の消耗が激しくなる等の問題が生じる恐れがあるためである。 As the mixed metal powder containing these Cu powder and low linear expansion metal powder, those containing 30 wt% or more and 90 wt% or less of Cu powder and 10 wt% or more and 70 wt% or less of low linear expansion metal powder can be preferably used. This is because if the content of the low linear expansion metal powder is less than 10 wt%, the effect of reducing the linear expansion coefficient by blending the low linear expansion metal powder may be insufficient. Also, if the Cu powder content is less than 30 wt%, the formability (workability) of the bearing sleeve is lowered, and the required dimensional accuracy cannot be ensured, or there is a risk of problems such as excessive wear of the mold. Because there is.
また、軸受スリーブ８の補強効果を狙って、上記Ｃｕ粉末と、Ｆｅ−Ｎｉ合金粉末を含む混合金属粉末に、さらにＳＵＳ粉末を配合することも可能である。これにより、軸受スリーブの補強効果が得られる他、軸受スリーブの耐摩耗性向上が可能となる。 Further, for the purpose of reinforcing the bearing sleeve 8, it is also possible to further mix SUS powder with the mixed metal powder including the Cu powder and the Fe-Ni alloy powder. As a result, the effect of reinforcing the bearing sleeve can be obtained, and the wear resistance of the bearing sleeve can be improved.
ＳＵＳ粉末を含む混合金属粉末としては、３０ｗｔ％以上８０ｗｔ％以下のＣｕ粉末と、１０ｗｔ％以上６５ｗｔ％以下の低膨張金属粉末と、５ｗｔ％以上６０ｗｔ％以下のＳＵＳ粉末とを含むものが好ましい。上記範囲内で各粉末を配合することにより、軸受スリーブの低線膨張特性と耐摩耗性とを高レベルで両立することができる。 The mixed metal powder containing SUS powder preferably contains 30 wt% or more and 80 wt% or less of Cu powder, 10 wt% or more and 65 wt% or less of low expansion metal powder, and 5 wt% or more and 60 wt% or less of SUS powder. By blending each powder within the above range, both the low linear expansion characteristic and the wear resistance of the bearing sleeve can be achieved at a high level.
このように、軸受スリーブは、Ｃｕ粉末と低線膨張金属粉末としてのＦｅ−Ｎｉ合金粉末、あるいはＣｕ粉末とＦｅ−Ｎｉ合金粉末、さらにＳＵＳ粉末との混合金属粉末で形成されるが、これら混合金属粉末に、さらにＳｎやＺｎなどの低融点金属を配合することもできる。この低融点金属は、焼結時に溶融（液相化）してＣｕ粉末や低線膨張金属粉末のバインダとして機能する。なお、ここでいう低融点金属は、上記混合金属粉末を圧縮成形した後、焼結する際の温度（焼結温度）以下で溶融する金属を指す。 As described above, the bearing sleeve is formed of Cu powder and Fe—Ni alloy powder as low linear expansion metal powder, or mixed metal powder of Cu powder and Fe—Ni alloy powder, and SUS powder. A low melting point metal such as Sn or Zn can also be added to the metal powder. This low melting point metal melts (liquid phase) during sintering and functions as a binder for Cu powder or low linear expansion metal powder. In addition, the low melting point metal here refers to a metal that melts at a temperature (sintering temperature) or lower during sintering after compression molding of the mixed metal powder.
上記組成の混合金属粉末で形成された軸受スリーブは、その内周面に、動圧発生部を形成した構成とすることもできる。この場合、軸受スリーブのラジアル軸受面となる動圧発生部形成領域と、支持すべき軸部材の外周面との間のラジアル軸受隙間に流体の動圧作用が生じ、軸部材が回転自在に非接触支持される。 The bearing sleeve formed of the mixed metal powder having the above composition may have a configuration in which a dynamic pressure generating portion is formed on the inner peripheral surface thereof. In this case, a fluid dynamic pressure action is generated in the radial bearing gap between the dynamic pressure generating portion forming region serving as the radial bearing surface of the bearing sleeve and the outer peripheral surface of the shaft member to be supported, and the shaft member is not rotatable. Contact supported.
上記軸受スリーブを備えた流体軸受装置は、例えばこの流体軸受装置を組み込んだディスク装置のスピンドルモータとして提供することが可能である。 The hydrodynamic bearing device including the bearing sleeve can be provided as a spindle motor of a disk device incorporating the hydrodynamic bearing device, for example.
このように、本発明によれば、温度変化に伴う軸受剛性の低下を抑え、かつ回転時のロストルクを低減した流体軸受装置を提供することができる。 As described above, according to the present invention, it is possible to provide a hydrodynamic bearing device that suppresses a decrease in bearing rigidity due to a temperature change and reduces a loss torque during rotation.
以下、本発明の一実施形態を図面に基づいて説明する。 Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
図１は、本発明の一実施形態に係る流体軸受装置（動圧軸受装置）１を組込んだ情報機器用スピンドルモータの一構成例を概念的に示している。このスピンドルモータは、ＨＤＤ等のディスク駆動装置に用いられるもので、軸部材２を回転自在に非接触支持する流体軸受装置１と、軸部材２に装着されたディスクハブ３と、例えば半径方向のギャップを介して対向させたステータコイル４およびロータマグネット５とを備えている。ステータコイル４はブラケット６の外周に取付けられ、ロータマグネット５は、ディスクハブ３の内周に取付けられている。ディスクハブ３は、その外周に磁気ディスク等のディスク状情報記憶媒体（以下、単にディスクという。）Ｄを一枚または複数枚（図１では２枚）保持している。このように構成されたスピンドルモータにおいて、ステータコイル４に通電すると、ステータコイル４とロータマグネット５との間に発生する電磁力でロータマグネット５が回転し、これに伴って、ディスクハブ３およびディスクハブ３に保持されたディスクＤが軸部材２と一体に回転する。 FIG. 1 conceptually shows one configuration example of a spindle motor for information equipment incorporating a fluid dynamic bearing device (dynamic pressure bearing device) 1 according to an embodiment of the present invention. This spindle motor is used in a disk drive device such as an HDD, and includes a hydrodynamic bearing device 1 that rotatably supports a shaft member 2 in a non-contact manner, a disk hub 3 mounted on the shaft member 2, and a radial direction, for example. A stator coil 4 and a rotor magnet 5 are provided to face each other through a gap. The stator coil 4 is attached to the outer periphery of the bracket 6, and the rotor magnet 5 is attached to the inner periphery of the disk hub 3. The disk hub 3 holds one or a plurality (two in FIG. 1) of a disk-shaped information storage medium (hereinafter simply referred to as a disk) D such as a magnetic disk on its outer periphery. In the spindle motor configured as described above, when the stator coil 4 is energized, the rotor magnet 5 is rotated by the electromagnetic force generated between the stator coil 4 and the rotor magnet 5. The disk D held by the hub 3 rotates integrally with the shaft member 2.
図２は、流体軸受装置１を示している。この流体軸受装置１は、軸部材２と、ハウジング７と、ハウジング７に固定された軸受スリーブ８、およびシール部材９とを主な構成要素として構成されている。なお、説明の便宜上、ハウジング７の底部７ｂの側を下側、底部７ｂと反対の側を上側として以下説明する。 FIG. 2 shows the hydrodynamic bearing device 1. The hydrodynamic bearing device 1 includes a shaft member 2, a housing 7, a bearing sleeve 8 fixed to the housing 7, and a seal member 9 as main components. For convenience of explanation, the bottom 7b side of the housing 7 will be described below, and the side opposite to the bottom 7b will be described as the upper side.
軸部材２は、例えばステンレス鋼等の金属材料で形成され、軸部２ａと、軸部２ａの下端に一体又は別体に設けられたフランジ部２ｂとを備えている。なお、軸部材２は、金属材料と樹脂材料とのハイブリッド構造とすることもでき、その場合、軸部２ａの少なくとも外周面２ａ１を含む鞘部が上記金属で形成され、残りの箇所（例えば軸部２ａの芯部やフランジ部２ｂ）が樹脂で形成される。なお、フランジ部２ｂの強度を確保するため、フランジ部２ｂを樹脂・金属のハイブリッド構造とし、軸部２ａの鞘部と共に、フランジ部２ｂの芯部を金属製とすることもできる。 The shaft member 2 is formed of a metal material such as stainless steel, for example, and includes a shaft portion 2a and a flange portion 2b provided integrally or separately at the lower end of the shaft portion 2a. In addition, the shaft member 2 can also have a hybrid structure of a metal material and a resin material. In this case, the sheath portion including at least the outer peripheral surface 2a1 of the shaft portion 2a is formed of the metal, and the remaining portion (for example, the shaft portion) The core part of the part 2a and the flange part 2b) are formed of resin. In order to secure the strength of the flange portion 2b, the flange portion 2b can be made of a resin / metal hybrid structure, and the core portion of the flange portion 2b can be made of metal together with the sheath portion of the shaft portion 2a.
ハウジング７は、ＬＣＰやＰＰＳ、ＰＥＥＫ等をベース樹脂とする樹脂組成物で射出成形され、例えば図２に示すように、筒部７ａと、筒部７ａの下端に一体に形成された底部７ｂとで構成される。ハウジング７を構成する上記樹脂組成物としては、例えば、ガラス繊維等の繊維状充填材、チタン酸カリウム等のウィスカ状充填材、マイカ等の鱗片状充填材、カーボン繊維、カーボンブラック、黒鉛、カーボンナノマテリアル、各種金属粉等の繊維状または粉末状の導電性充填材を、目的に応じて上記ベース樹脂に適量配合したものが使用可能である。 The housing 7 is injection-molded with a resin composition having LCP, PPS, PEEK or the like as a base resin. For example, as shown in FIG. 2, a cylindrical portion 7 a and a bottom portion 7 b integrally formed at the lower end of the cylindrical portion 7 a Consists of. Examples of the resin composition constituting the housing 7 include fibrous fillers such as glass fibers, whisker-like fillers such as potassium titanate, scaly fillers such as mica, carbon fibers, carbon black, graphite, carbon A material in which an appropriate amount of a fibrous or powdery conductive filler such as nanomaterials or various metal powders is blended with the base resin according to the purpose can be used.
底部７ｂの上端面７ｂ１の全面又は一部環状領域には、スラスト動圧発生部として、例えば図示は省略するが、複数の動圧溝をスパイラル形状に配列した領域が形成される。この動圧溝形成領域は、フランジ部２ｂの下端面２ｂ２と対向し、軸部材２の回転時には、下端面２ｂ２との間に第二スラスト軸受部Ｔ２のスラスト軸受隙間を形成する（図２を参照）。この種の動圧溝は、ハウジング７を成形する成形型の所要部位（上端面７ｂ１を成形する部位）に、動圧溝を成形する溝型を加工しておくことで、ハウジング７と同時成形することができる。また、上端面７ｂ１から軸方向上方に所定寸法だけ離れた位置には、軸受スリーブ８の下端面８ｃと係合して軸方向の位置決めを行う段部７ｄが一体に形成される。 For example, although not shown, a region in which a plurality of dynamic pressure grooves are arranged in a spiral shape is formed on the entire upper surface 7b1 of the bottom 7b or a partial annular region as a thrust dynamic pressure generating portion. This dynamic pressure groove forming region faces the lower end surface 2b2 of the flange portion 2b, and forms a thrust bearing gap of the second thrust bearing portion T2 between the lower end surface 2b2 when the shaft member 2 rotates (see FIG. 2). reference). This type of dynamic pressure groove is formed at the same time as the housing 7 by forming a groove mold for forming the dynamic pressure groove in a required part of the mold for molding the housing 7 (a part for molding the upper end surface 7b1). can do. Further, a step portion 7d that engages with the lower end surface 8c of the bearing sleeve 8 and performs axial positioning is integrally formed at a position that is separated from the upper end surface 7b1 in the axial direction by a predetermined dimension.
軸受スリーブ８は、Ｃｕおよび低線膨張金属を主成分とする焼結金属の多孔質体で円筒状に形成され、ハウジング７の内周面７ｃに固定される。 The bearing sleeve 8 is formed of a sintered metal porous body mainly composed of Cu and a low linear expansion metal and is formed in a cylindrical shape, and is fixed to the inner peripheral surface 7 c of the housing 7.
軸受スリーブ８の内周面８ａの全面又は一部円筒領域には、ラジアル動圧発生部としての動圧溝が形成される。この実施形態では、例えば図３（ａ）に示すように、複数の動圧溝８ａ１、８ａ２をヘリングボーン形状に配列した領域が軸方向に離隔して２箇所形成される。上側の動圧溝８ａ１の形成領域では、動圧溝８ａ１が、軸方向中心ｍ（上下の傾斜溝間領域の軸方向中央）に対して軸方向非対称に形成されており、軸方向中心ｍより上側領域の軸方向寸法Ｘ１が下側領域の軸方向寸法Ｘ２よりも大きくなっている。 A dynamic pressure groove as a radial dynamic pressure generating portion is formed on the entire inner surface 8a of the bearing sleeve 8 or a partial cylindrical region. In this embodiment, for example, as shown in FIG. 3A, two regions having a plurality of dynamic pressure grooves 8a1 and 8a2 arranged in a herringbone shape are formed apart from each other in the axial direction. In the formation region of the upper dynamic pressure groove 8a1, the dynamic pressure groove 8a1 is formed to be axially asymmetric with respect to the axial center m (the axial center of the upper and lower inclined groove regions). The axial dimension X1 of the upper region is larger than the axial dimension X2 of the lower region.
軸受スリーブ８の下端面８ｃの全面または一部環状領域には、スラスト動圧発生部として、例えば図３（ｂ）に示すように、複数の動圧溝８ｃ１をスパイラル形状に配列した領域が形成される。 For example, as shown in FIG. 3B, a region where a plurality of dynamic pressure grooves 8c1 are arranged in a spiral shape is formed as a thrust dynamic pressure generating portion on the entire lower surface 8c of the bearing sleeve 8 or a partial annular region. Is done.
この軸受スリーブ８は、例えば純Ｃｕ粉末と、低線膨張金属粉末としてのＳｕｐｅｒ−Ｉｎｖａｒ型合金粉末（以下、単にＳ.Ｉｎｖａｒ粉末という。）と、ＳＵＳ粉末と（場合によっては、さらに低融点金属粉末としてのＳｎ粉末やＰ粉末、あるいはこれらの合金粉末と）を含む混合金属粉末を円筒状に圧縮成形し、これを所定の焼結温度で焼結することで得られる。この実施形態では、さらに寸法サイジング、回転サイジング、溝サイジング加工が順に施され、これにより焼結体が所定寸法にサイジングされると共に、焼結体の表面に動圧溝８ａ１、８ｃ１等が形成される。なお、圧縮成形時の成形性、あるいは完成品の摺動特性を改善する目的で、上記混合金属粉末に、さらに黒鉛（グラファイト）などの固体潤滑剤を配合することもできる。 The bearing sleeve 8 includes, for example, pure Cu powder, Super-Invar type alloy powder (hereinafter simply referred to as S. Invar powder) as low linear expansion metal powder, and SUS powder (in some cases, a low melting point metal). It is obtained by compressing and molding a mixed metal powder containing Sn powder, P powder, or an alloy powder thereof as a powder into a cylindrical shape and sintering it at a predetermined sintering temperature. In this embodiment, dimension sizing, rotational sizing, and groove sizing are further performed in this order, whereby the sintered body is sized to a predetermined size, and dynamic pressure grooves 8a1, 8c1, etc. are formed on the surface of the sintered body. The In addition, for the purpose of improving the moldability at the time of compression molding or the sliding characteristics of the finished product, a solid lubricant such as graphite can be further blended with the mixed metal powder.
軸受スリーブ８の材料として使用する純Ｃｕ粉末粒子のサイズは、Ｓ.Ｉｎｖａｒ粉末やＳＵＳ粉末と同等、あるいはそれ以下であることが好ましい。また、この実施形態における純Ｃｕ粉末とＳ.Ｉｎｖａｒ粉末、およびＳＵＳ粉末との配合比率は、純Ｃｕ粉末：３０ｗｔ％以上８０ｗｔ％以下、Ｓ.Ｉｎｖａｒ粉末：１０ｗｔ％以上６５ｗｔ％以下、ＳＵＳ粉末：５ｗｔ％以上６０ｗｔ％以下、であることが好ましい。これは、ＳＵＳ粉末の配合量が５ｗｔ％未満だと、ＳＵＳ粉末による補強効果および耐摩耗性改善効果が不十分となる恐れがあるためである。また、純Ｃｕ粉末は延展性に優れ、焼結体の成形性、特に焼結後のサイジング加工性を高めるために好ましい材料であるが、その配合比率が減少すると、焼結後のサイジング加工、特に上記動圧溝８ａ１、８ｃ１等の溝サイジングが困難になる恐れがある。このような観点から、純Ｃｕ粉末の配合比率は３０ｗｔ％以上とするのがよい。 The size of the pure Cu powder particles used as the material of the bearing sleeve 8 is preferably equal to or smaller than that of S. Invar powder or SUS powder. Further, the blending ratio of the pure Cu powder to the S. Invar powder and the SUS powder in this embodiment is as follows: pure Cu powder: 30 wt% to 80 wt%, S. Invar powder: 10 wt% to 65 wt%, SUS powder: It is preferably 5 wt% or more and 60 wt% or less. This is because if the blending amount of the SUS powder is less than 5 wt%, the reinforcing effect and the wear resistance improving effect by the SUS powder may be insufficient. In addition, pure Cu powder is excellent in spreadability and is a preferable material for enhancing the moldability of the sintered body, particularly sizing workability after sintering, but when its blending ratio is reduced, sizing processing after sintering, In particular, the sizing of the dynamic pressure grooves 8a1, 8c1, etc. may be difficult. From such a viewpoint, the blending ratio of the pure Cu powder is preferably 30 wt% or more.
焼結時の温度（焼結温度）は、７５０℃以上１０００℃以下であることが好ましく、８００℃以上９５０℃以下であればより好ましい。これは、焼結温度が７５０℃未満だと各粉末間の焼結作用が十分でないことから焼結体の強度が低下し、１０００℃を超えると、上記と同様の理由で、つまりサイジング加工時の溝成形性に支障を来す恐れがあるためである。 The temperature during sintering (sintering temperature) is preferably 750 ° C. or higher and 1000 ° C. or lower, and more preferably 800 ° C. or higher and 950 ° C. or lower. This is because when the sintering temperature is less than 750 ° C., the sintering action between the powders is not sufficient, so the strength of the sintered body is reduced. This is because there is a risk of disturbing the groove formability.
また、上記混合金属粉末にＳｎ粉末を配合する場合、その配合比率は、全混合金属粉末に対して０．２ｗｔ％以上１０ｗｔ％以下とするのがよい。この配合範囲内であれば、Ｓｎ粉末は、上記焼結温度で溶融（液相化）し、他の粉末（純Ｃｕ粉末、Ｓ.Ｉｎｖａｒ粉末など）間のバインダとして機能する。また、上記配合範囲内で純Ｃｕ粉末と合金化することで、焼結体の耐摩耗性を向上させつつも、純Ｃｕが本来有する優れた加工性（特に塑性変形性）を適度に維持することができる。 Moreover, when mix | blending Sn powder with the said mixed metal powder, the mixture ratio is good to set it as 0.2 wt% or more and 10 wt% or less with respect to all the mixed metal powders. Within this blending range, the Sn powder melts (liquid phase) at the sintering temperature and functions as a binder between other powders (pure Cu powder, S. Invar powder, etc.). Further, by alloying with pure Cu powder within the above blending range, the excellent workability (especially plastic deformability) inherent in pure Cu is moderately maintained while improving the wear resistance of the sintered body. be able to.
このようにして、所定割合の純Ｃｕ粉末と低膨張金属粉末（Ｓ.Ｉｎｖａｒ粉末）、さらにはＳＵＳ粉末とＳｎ粉末とを含む混合金属粉末を使用することで、低い線膨張係数に加えて高い機械的強度を有し、かつ軸受面の摺動特性（耐摩耗性、なじみ性）や寸法精度に優れた軸受スリーブ８を得ることができる。完成品としての軸受スリーブ８の密度は例えば７．０〜７．４［ｇ／ｃｍ3］、表面開孔率は２〜１０［ｖｏｌ％］である。一例として、上記純Ｃｕ粉末、Ｓ．Ｉｎｖａｒ粉末、ＳＵＳ粉末、Ｓｎ粉末を含む混合金属粉末で軸受スリーブ８を形成した場合の、軸受スリーブ８内部の顕微鏡写真を図１１に示す。 In this way, by using a mixed metal powder including a predetermined proportion of pure Cu powder and low expansion metal powder (S. Invar powder), and further SUS powder and Sn powder, it is high in addition to a low linear expansion coefficient. It is possible to obtain a bearing sleeve 8 having mechanical strength and excellent in sliding characteristics (wear resistance, conformability) and dimensional accuracy of the bearing surface. The density of the bearing sleeve 8 as a finished product is, for example, 7.0 to 7.4 [g / cm 3 ], and the surface opening ratio is 2 to 10 [vol%]. As an example, the pure Cu powder, S.I. FIG. 11 shows a micrograph of the inside of the bearing sleeve 8 when the bearing sleeve 8 is formed of a mixed metal powder containing Invar powder, SUS powder, and Sn powder.
シール部材９は、例えば樹脂材料又は金属材料で環状に形成され、ハウジング７の筒部７ａの上端部内周に配設される。シール部材９の内周面９ａは、軸部２ａの外周に設けられたテーパ面２ａ２と所定のシール空間Ｓを介して対向する。なお、軸部２ａのテーパ面２ａ２は上側（ハウジング７に対して外部側）に向かって漸次縮径し、軸部材２の回転時には毛細管力シールおよび遠心力シールとしても機能する。 The seal member 9 is formed in an annular shape with, for example, a resin material or a metal material, and is disposed on the inner periphery of the upper end portion of the cylindrical portion 7 a of the housing 7. An inner peripheral surface 9a of the seal member 9 is opposed to a tapered surface 2a2 provided on the outer periphery of the shaft portion 2a via a predetermined seal space S. The tapered surface 2a2 of the shaft portion 2a is gradually reduced in diameter toward the upper side (outside of the housing 7), and also functions as a capillary force seal and a centrifugal force seal when the shaft member 2 rotates.
ハウジング７の内周に、軸部材２および軸受スリーブ８を挿入し、段部７ｄにより軸受スリーブ８の軸方向の位置決めを行った上で、軸受スリーブ８をハウジング７の内周面７ｃに、例えば接着、圧入、溶着等の手段により固定する。そして、シール部材９を、その下端面９ｂを軸受スリーブ８の上端面８ｂに当接させた上で、ハウジング７の内周面７ｃに固定する。その後、ハウジング７の内部空間に潤滑油を充満させることで、流体軸受装置１の組立が完了する。このとき、シール部材９で密封されたハウジング７の内部空間（軸受スリーブ８の内部空孔を含む）に充満した潤滑油の油面は、シール空間Ｓの範囲内に維持される。 After the shaft member 2 and the bearing sleeve 8 are inserted into the inner periphery of the housing 7 and the bearing sleeve 8 is positioned in the axial direction by the step portion 7d, the bearing sleeve 8 is placed on the inner peripheral surface 7c of the housing 7, for example, Fix by means of adhesion, press-fitting, welding, etc. The seal member 9 is fixed to the inner peripheral surface 7 c of the housing 7 with the lower end surface 9 b abutting against the upper end surface 8 b of the bearing sleeve 8. Then, the assembly of the hydrodynamic bearing device 1 is completed by filling the internal space of the housing 7 with lubricating oil. At this time, the oil level of the lubricating oil filled in the internal space of the housing 7 (including the internal holes of the bearing sleeve 8) sealed by the seal member 9 is maintained within the range of the seal space S.
軸部材２の回転時、軸受スリーブ８の内周面８ａのラジアル軸受面となる領域（上下２箇所の動圧溝８ａ１、８ａ２形成領域）は、軸部２ａの外周面２ａ１とラジアル軸受隙間を介して対向する。そして、軸部材２の回転に伴い、上記ラジアル軸受隙間の潤滑油が動圧溝８ａ１、８ａ２の軸方向中心ｍ側に押し込まれ、その圧力が上昇する。このような動圧溝８ａ１、８ａ２の動圧作用によって、軸部２ａを非接触支持する第一ラジアル軸受部Ｒ１と第二ラジアル軸受部Ｒ２がそれぞれ構成される（図２を参照）。 When the shaft member 2 rotates, a region (a region where the dynamic pressure grooves 8a1 and 8a2 are formed in the upper and lower portions) of the inner peripheral surface 8a of the bearing sleeve 8 is a radial bearing gap between the outer peripheral surface 2a1 of the shaft portion 2a. Opposite through. As the shaft member 2 rotates, the lubricating oil in the radial bearing gap is pushed toward the axial center m of the dynamic pressure grooves 8a1 and 8a2, and the pressure rises. The dynamic pressure action of the dynamic pressure grooves 8a1 and 8a2 constitutes a first radial bearing portion R1 and a second radial bearing portion R2 that support the shaft portion 2a in a non-contact manner (see FIG. 2).
これと同時に、フランジ部２ｂの上端面２ｂ１とこれに対向する軸受スリーブ８の下端面８ｃのスラスト軸受面となる領域（動圧溝８ｃ１形成領域）との間のスラスト軸受隙間、およびフランジ部２ｂの下端面２ｂ２とこれに対向する底部７ｂの上端面７ｂ１のスラスト軸受面となる領域（動圧溝形成領域）との間のスラスト軸受隙間に、動圧溝の動圧作用により潤滑油の油膜がそれぞれ形成される。そして、これら油膜の圧力によって、フランジ部２ｂを両スラスト方向に回転自在に非接触支持する第一スラスト軸受部Ｔ１と、第二スラスト軸受部Ｔ２が構成される（図２を参照）。 At the same time, the thrust bearing gap between the upper end surface 2b1 of the flange portion 2b and the region (the dynamic pressure groove 8c1 formation region) that becomes the thrust bearing surface of the lower end surface 8c of the bearing sleeve 8 facing the flange portion 2b, and the flange portion 2b. An oil film of lubricating oil is formed in the thrust bearing gap between the lower end surface 2b2 of the upper portion and the region (dynamic pressure groove forming region) of the upper end surface 7b1 of the bottom portion 7b opposite to the thrust bearing surface by the dynamic pressure action of the dynamic pressure groove. Are formed respectively. The pressure of these oil films forms a first thrust bearing portion T1 and a second thrust bearing portion T2 that support the flange portion 2b in a non-contact manner so as to be rotatable in both thrust directions (see FIG. 2).
高温雰囲気下での使用時、軸部材２と軸受スリーブ８は共に膨張し、軸部２ａの外周面２ａ１、軸受スリーブ８のラジアル軸受面を含む内周面８ａが外径側に変位する。ここで、軸受スリーブ８は、Ｓ.Ｉｎｖａｒ粉末を含む混合金属粉末で形成されているので、温度上昇に伴う軸受スリーブ８の内周面８ａの変位量は、軸部２ａの外周面２ａ１の変位量と比べてほぼ等しく、あるいは小さくなる。これにより、内周面８ａのラジアル軸受面とこれに対向する外周面２ａ１との間のラジアル軸受隙間を、温度上昇前の隙間と比べて少なくとも同レベルに保つことができる。従って、温度上昇により潤滑油の粘度が低下する場合であっても、軸受剛性の低下を極力抑えることができる。また、温度低下時には、内周面８ａと外周面２ａ１との間のラジアル軸受隙間を、低下前と比べて少なくとも同レベルに保つことができる。従って、温度低下に伴い潤滑油の粘度が増加する場合であっても、回転時（特に回転開始時）のロストルクを極力低減することができる。 When used in a high temperature atmosphere, the shaft member 2 and the bearing sleeve 8 both expand, and the outer peripheral surface 2a1 of the shaft portion 2a and the inner peripheral surface 8a including the radial bearing surface of the bearing sleeve 8 are displaced to the outer diameter side. Here, since the bearing sleeve 8 is formed of a mixed metal powder containing S. Invar powder, the displacement amount of the inner peripheral surface 8a of the bearing sleeve 8 with the temperature rise is the displacement of the outer peripheral surface 2a1 of the shaft portion 2a. It is almost equal to or smaller than the amount. Thereby, the radial bearing gap between the radial bearing surface of the inner circumferential surface 8a and the outer circumferential surface 2a1 facing the radial bearing surface can be kept at least at the same level as the gap before the temperature rises. Therefore, even when the viscosity of the lubricating oil is reduced due to a temperature rise, the reduction in bearing rigidity can be suppressed as much as possible. Further, when the temperature is lowered, the radial bearing gap between the inner peripheral surface 8a and the outer peripheral surface 2a1 can be kept at least at the same level as before the decrease. Therefore, even when the viscosity of the lubricating oil increases as the temperature decreases, the loss torque at the time of rotation (particularly at the start of rotation) can be reduced as much as possible.
また、Ｓ.Ｉｎｖａｒ粉末に加えて、上記混合金属粉末にＳＵＳ粉末を混合することによって、内周面８ａのラジアル軸受面となる領域（動圧溝８ａ１、８ａ２形成領域）の硬度が高められる。これにより、対向面２ａ１、８ａ間の硬度差が小さくなり、軸受スリーブ８と軸部２ａとが互いに接触摺動する場合（例えば回転開始時）であっても、何れか一方、あるいは双方の部材が摩耗するといった事態を可及的に防ぐことができる。 In addition to the S. Invar powder, the SUS powder is mixed with the mixed metal powder, whereby the hardness of the region (dynamic pressure groove 8a1, 8a2 forming region) that becomes the radial bearing surface of the inner peripheral surface 8a is increased. As a result, the difference in hardness between the opposing surfaces 2a1 and 8a is reduced, and even when the bearing sleeve 8 and the shaft portion 2a slide in contact with each other (for example, at the start of rotation), either one or both members Can be prevented as much as possible.
以上、本発明の一実施形態を説明したが、本発明はこの実施形態に限定されるものではない。 Although one embodiment of the present invention has been described above, the present invention is not limited to this embodiment.
以上の実施形態では、ハウジング７として筒部７ａおよび底部７ｂを樹脂で一体成形したものを説明したが、これ以外にも、例えば図示は省略するが、筒部７ａを底部７ｂとは別体に樹脂で成形することもできる。この場合には、例えばシール部材９を筒部７ａと一体に樹脂で成形することもでき、これによれば、軸受スリーブ８の軸方向位置決めを、筒部７ａと一体に成形したシール部の下端面に軸受スリーブ８の上端面８ｂを当接させることで行うことができる。また、上記ハウジング７は、何も樹脂材料の射出成形品に限ったものではなく、例えば金属材料の旋削加工品、あるいはプレス加工品であってもよい。 In the above embodiment, the cylindrical portion 7a and the bottom portion 7b are integrally molded with the resin as the housing 7. However, for example, although not shown, the cylindrical portion 7a is separated from the bottom portion 7b. It can also be molded with resin. In this case, for example, the seal member 9 can be molded integrally with the cylindrical portion 7a from resin, and according to this, the axial positioning of the bearing sleeve 8 can be performed under the seal portion molded integrally with the cylindrical portion 7a. This can be done by bringing the upper end surface 8b of the bearing sleeve 8 into contact with the end surface. The housing 7 is not limited to an injection-molded product made of a resin material, and may be, for example, a turning product of a metal material or a pressed product.
また、以上の実施形態では、ラジアル軸受部Ｒ１、Ｒ２およびスラスト軸受部Ｔ１、Ｔ２として、へリングボーン形状やスパイラル形状の動圧溝により潤滑流体の動圧作用を発生させる構成を例示しているが、本発明はこれに限定されるものではない。 In the above embodiment, the radial bearing portions R1 and R2 and the thrust bearing portions T1 and T2 are configured to generate the dynamic pressure action of the lubricating fluid by the herringbone shape or spiral shape dynamic pressure grooves. However, the present invention is not limited to this.
例えば、ラジアル軸受部Ｒ１、Ｒ２として、いわゆるステップ軸受や多円弧軸受を採用してもよい。 For example, so-called step bearings or multi-arc bearings may be employed as the radial bearing portions R1 and R2.
図４は、ラジアル軸受部Ｒ１、Ｒ２の一方又は双方を多円弧軸受で構成した場合の一例を示している。同図において、軸受スリーブ８の内周面８ａのラジアル軸受面となる領域は、複数の円弧面８ａ３（この図では３円弧面）で構成されている。各円弧面８ａ３は、回転軸心Ｏからそれぞれ等距離オフセットした点を中心とする偏心円弧面であり、円周方向で等間隔に形成される。各偏心円弧面８ａ３の間には軸方向の分離溝８ａ４がそれぞれ形成される。 FIG. 4 shows an example in which one or both of the radial bearing portions R1 and R2 are constituted by multi-arc bearings. In the same figure, the area | region used as the radial bearing surface of the internal peripheral surface 8a of the bearing sleeve 8 is comprised by several arc surface 8a3 (this figure 3 arc surface). Each arc surface 8a3 is an eccentric arc surface centered at a point offset from the rotation axis O by an equal distance, and is formed at equal intervals in the circumferential direction. An axial separation groove 8a4 is formed between each eccentric arc surface 8a3.
軸受スリーブ８の内周面８ａに軸部材２の軸部２ａを挿入することにより、軸受スリーブ８の偏心円弧面８ａ３および分離溝８ａ４と、軸部２ａの真円状外周面２ａ１との間に、第一および第二ラジアル軸受部Ｒ１、Ｒ２の各ラジアル軸受隙間がそれぞれ形成される。ラジアル軸受隙間のうち、偏心円弧面８ａ３と真円状外周面２ａ１とで形成される領域は、隙間幅を円周方向の一方で漸次縮小させたくさび状隙間８ａ５となる。くさび状隙間８ａ５の縮小方向は軸部材２の回転方向に一致している。 By inserting the shaft portion 2a of the shaft member 2 into the inner peripheral surface 8a of the bearing sleeve 8, the eccentric arc surface 8a3 and the separation groove 8a4 of the bearing sleeve 8 and the perfect circular outer peripheral surface 2a1 of the shaft portion 2a are interposed. The radial bearing gaps of the first and second radial bearing portions R1 and R2 are respectively formed. In the radial bearing gap, a region formed by the eccentric arc surface 8a3 and the perfect circular outer peripheral surface 2a1 is a wedge-shaped gap 8a5 in which the gap width is gradually reduced in the circumferential direction. The reduction direction of the wedge-shaped gap 8a5 coincides with the rotation direction of the shaft member 2.
図５は、第一および第二ラジアル軸受部Ｒ１、Ｒ２を構成する多円弧軸受の他の実施形態を示すものである。この実施形態では、図４に示す構成において、各偏心円弧面８ａ３の最小隙間側の所定領域θが、それぞれ回転軸心Ｏを中心とする同心の円弧で構成されている。従って、各所定領域θにおけるラジアル軸受隙間（最小隙間）８ａ６は一定となる。このような構成の多円弧軸受は、テーパ・フラット軸受と称されることもある。 FIG. 5 shows another embodiment of the multi-arc bearing constituting the first and second radial bearing portions R1 and R2. In this embodiment, in the configuration shown in FIG. 4, the predetermined region θ on the minimum gap side of each eccentric arc surface 8 a 3 is configured by concentric arcs with the rotation axis O as the center. Accordingly, the radial bearing gap (minimum gap) 8a6 in each predetermined region θ is constant. The multi-arc bearing having such a configuration may be referred to as a tapered flat bearing.
図６では、軸受スリーブ８の内周面８ａのラジアル軸受面となる領域が３つの円弧面８ａ７で形成されると共に、３つの円弧面８ａ７の中心は、回転軸心Ｏから等距離オフセットされている。３つの偏心円弧面８ａ７で区画される各領域において、ラジアル軸受隙間８ａ８は、円周方向の両方向に対してそれぞれ漸次縮小した形状を有している。 In FIG. 6, a region that becomes a radial bearing surface of the inner peripheral surface 8 a of the bearing sleeve 8 is formed by three arc surfaces 8 a 7, and the centers of the three arc surfaces 8 a 7 are offset from the rotation axis O by an equal distance. Yes. In each region defined by the three eccentric arc surfaces 8a7, the radial bearing gap 8a8 has a shape that is gradually reduced with respect to both circumferential directions.
以上説明した第一および第二ラジアル軸受部Ｒ１、Ｒ２の多円弧軸受は、何れもいわゆる３円弧軸受であるが、これに限らず、いわゆる４円弧軸受、５円弧軸受、さらには６円弧以上の数の円弧面で構成された多円弧軸受を採用してもよい。また、ラジアル軸受部Ｒ１、Ｒ２のように、２つのラジアル軸受部を軸方向に離隔して設けた構成とする他、軸受スリーブ８の内周面８ａの上下領域に亘って１つのラジアル軸受部を設けた構成としてもよい。 The multi-arc bearings of the first and second radial bearing portions R1 and R2 described above are all so-called three-arc bearings, but are not limited thereto, so-called four-arc bearings, five-arc bearings, and more than six arcs. You may employ | adopt the multi-arc bearing comprised by the several circular arc surface. Further, in addition to the configuration in which the two radial bearing portions are separated from each other in the axial direction as in the radial bearing portions R1 and R2, one radial bearing portion extends over the upper and lower regions of the inner peripheral surface 8a of the bearing sleeve 8. It is good also as a structure which provided.
また、スラスト軸受部Ｔ１、Ｔ２の一方又は双方は、例えば図示は省略するが、スラスト軸受面となる領域に、複数の半径方向溝形状の動圧溝を円周方向所定間隔に設けた、いわゆるステップ軸受、いわゆる波型軸受（ステップ型が波型になったもの）等で構成することもできる。 One or both of the thrust bearing portions T1 and T2, for example, are not shown in the figure, but a plurality of radial groove-shaped dynamic pressure grooves are provided at predetermined intervals in the circumferential direction in a region serving as a thrust bearing surface. It can also be constituted by a step bearing, a so-called corrugated bearing (the corrugated step mold) or the like.
また、以上の実施形態では、ラジアル軸受部Ｒ１、Ｒ２やスラスト軸受部Ｔ１、Ｔ２を動圧軸受で構成した場合を説明したが、これ以外の軸受で構成することもできる。例えば、ラジアル軸受面となる軸受スリーブ８の内周面８ａを、動圧発生部としての動圧溝８ａ１や円弧面８ａ３を設けない真円内周面とし、この内周面と対向する軸部２ａの真円状外周面２ａ１とで、いわゆる真円軸受を構成することができる。 Moreover, although the radial bearing part R1 and R2 and the thrust bearing part T1 and T2 were comprised by the dynamic pressure bearing in the above embodiment, it can also comprise by bearings other than this. For example, the inner peripheral surface 8a of the bearing sleeve 8 serving as a radial bearing surface is a perfect circular inner peripheral surface not provided with the dynamic pressure groove 8a1 or the circular arc surface 8a3 as a dynamic pressure generating portion, and the shaft portion opposed to the inner peripheral surface A so-called perfect circle bearing can be constituted by the perfect circular outer peripheral surface 2a1 of 2a.
また、以上の実施形態では、流体軸受装置１の内部に充満し、ラジアル軸受隙間や、スラスト軸受隙間に潤滑膜を形成する流体として、潤滑油を例示したが、それ以外にも各軸受隙間に潤滑膜を形成可能な流体、例えば空気等の気体や、磁性流体等の流動性を有する潤滑剤、あるいは潤滑グリース等を使用することもできる。 Further, in the above embodiment, the lubricating oil is exemplified as the fluid that fills the inside of the hydrodynamic bearing device 1 and forms a lubricating film in the radial bearing gap or the thrust bearing gap. A fluid capable of forming a lubricating film, for example, a gas such as air, a fluid lubricant such as a magnetic fluid, or lubricating grease may be used.
本発明の効果を実証するため、Ｃｕ粉末と低膨張金属粉末とを含む混合金属粉末で形成された試験体（実施例１〜４）と、従来組成の金属粉末（Ｃｕ粉末とＦｅ粉末との混合粉末）で形成された試験体（比較例）とについて、それぞれ線膨張係数測定試験を行い、線膨張係数を評価比較した。また、上記試験体（実施例１〜４）のうち、Ｃｕ粉末と低膨張金属粉末に加えて、さらにＳＵＳ粉末を含む混合金属粉末で形成された試験体（実施例２〜４）と従来品（比較例）について摩耗試験を行い、耐摩耗性を評価比較した。 In order to demonstrate the effect of the present invention, a test body (Examples 1 to 4) formed of a mixed metal powder containing Cu powder and a low expansion metal powder, and a metal powder (Cu powder and Fe powder of conventional composition) With respect to the test body (comparative example) formed with the mixed powder), a linear expansion coefficient measurement test was performed, and the linear expansion coefficient was evaluated and compared. Moreover, among the above test bodies (Examples 1 to 4), in addition to the Cu powder and the low expansion metal powder, the test body (Examples 2 to 4) formed of a mixed metal powder further containing a SUS powder and the conventional product. A wear test was conducted on (Comparative Example), and the wear resistance was evaluated and compared.
試験材料には、純Ｃｕ粉末として福田金属箔粉工業（株）製のＣＥ−１５を、低線膨張金属粉末としてのＳ．Ｉｎｖａｒ粉末には（株）アトミックス製のＳＵＰＥＲ ＩＮＶＡＲを、ＳＵＳ粉末として大同特殊鋼（株）製のＤＡＰ４１０Ｌ（ＳＵＳ４１０Ｌ）を、また、Ｆｅ粉末としてヘガネス（株）製のＮＣ１００．２４をそれぞれ用いた。また、低融点金属としてのＳｎ粉末には福田金属箔粉工業（株）製のＳｎ-Ａｔ-Ｗ３５０を、固体潤滑剤としての黒鉛には日本黒鉛工業（株）製のＥＣＢ−２５０をそれぞれ用いた。試験片（焼結金属材）の焼結温度は、比較例、実施例共に８７０℃とした。比較例と実施例、各々の混合金属粉末の組成は図７に示す通りである。また、各粉末の粒度分布は図８に示す通りである。 As test materials, CE-15 manufactured by Fukuda Metal Foil Powder Co., Ltd. was used as pure Cu powder, and S.P. SUPER INVAR manufactured by Atmix Co., Ltd. was used as the Invar powder, DAP410L (SUS410L) manufactured by Daido Steel Co., Ltd. as the SUS powder, and NC100.24 manufactured by Heganes Co., Ltd. as the Fe powder. . In addition, Sn-At-W350 manufactured by Fukuda Metal Foil Powder Co., Ltd. is used for Sn powder as a low melting point metal, and ECB-250 manufactured by Nippon Graphite Industry Co., Ltd. is used for graphite as a solid lubricant. It was. The sintering temperature of the test piece (sintered metal material) was 870 ° C. in both the comparative example and the example. The composition of the mixed metal powders of the comparative example and the example are as shown in FIG. Further, the particle size distribution of each powder is as shown in FIG.
線膨張係数測定試験は、比較例、実施例共に以下の条件で行った。
試験片 ；外径φ７．５ｍｍ×軸方向幅１０ｍｍ
測定温度 ；−４０℃〜１２０℃
昇温速度 ；５℃／ｍｉｎ
荷重 ；１０ｇｆ
窒素ガス流量；２００ｍｌ／ｍｉｎ
The linear expansion coefficient measurement test was performed under the following conditions in both the comparative example and the example.
Test piece: outer diameter φ7.5 mm × axial width 10 mm
Measurement temperature: -40 ° C to 120 ° C
Temperature increase rate: 5 ° C / min
Load: 10 gf
Nitrogen gas flow rate: 200 ml / min
また、摩耗試験は、比較例、実施例共に以下の条件で行った。
試験片 ；外径φ７．５ｍｍ×軸方向幅１０ｍｍ
相手試験片；外径φ４０ｍｍ×軸方向幅４ｍｍ
周速 ；５０ｍ／ｍｉｎ
面圧 ；１．３ＭＰａ
潤滑油 ；エステル油（１２ｍｍ2／ｓ）
試験時間 ；３ｈｒｓ
The abrasion test was performed under the following conditions in both the comparative example and the example.
Test piece: outer diameter φ7.5 mm × axial width 10 mm
Counter specimen: Outer diameter 40 mm x Axial width 4 mm
Peripheral speed: 50 m / min
Surface pressure: 1.3 MPa
Lubricating oil: Ester oil (12mm 2 / s)
Test time: 3 hrs
図９に線膨張係数測定試験結果を示す。同図に示すように、Ｓ．Ｉｎｖａｒ粉末を含まない試験体（比較例）では、高い線膨張係数を示した。これに対して、Ｓ．Ｉｎｖａｒ粉末を含む試験体（実施例１〜４）では、線膨張係数の値は小さいものとなった。 FIG. 9 shows the linear expansion coefficient measurement test results. As shown in FIG. The test body not containing Invar powder (comparative example) showed a high linear expansion coefficient. On the other hand, S.M. In the specimens (Examples 1 to 4) containing Invar powder, the value of the linear expansion coefficient was small.
図１０に摩耗試験結果を示す。同図に示すように、ＳＵＳ粉末を含まない試験体（比較例）では顕著な摩耗が確認された。これに対して、ＳＵＳ粉末を含む試験体（実施例２〜４）における摩耗量（摩耗深さ、摩耗痕面積）は、従来組成の試験体（比較例）に比べて非常に小さいものであった。 FIG. 10 shows the wear test results. As shown in the figure, remarkable wear was confirmed in the test body (comparative example) not containing SUS powder. On the other hand, the amount of wear (wear depth and wear scar area) in the specimens containing SUS powder (Examples 2 to 4) was much smaller than that of the specimen having the conventional composition (Comparative Example). It was.
以上より、試験を行ったＳ.Ｉｎｖａｒ粉末とＳＵＳ粉末との何れの組合わせ（実施例２〜４）においても、線膨張係数低減効果と耐摩耗性向上効果とを共に満足することが確認された。 From the above, it was confirmed that any combination of the tested S. Invar powder and SUS powder (Examples 2 to 4) satisfied both the linear expansion coefficient reduction effect and the wear resistance improvement effect. It was.
１ 流体軸受装置
２ 軸部材
３ ディスクハブ
４ ステータコイル
５ ロータマグネット
６ ブラケット
７ ハウジング
８ 軸受スリーブ
８ａ１、８ａ２ 動圧溝
８ｃ１ 動圧溝
９ シール部材
Ｓ シール空間
Ｒ１、Ｒ２ ラジアル軸受部
Ｔ１、Ｔ２ スラスト軸受部
DESCRIPTION OF SYMBOLS 1 Fluid dynamic bearing apparatus 2 Shaft member 3 Disc hub 4 Stator coil 5 Rotor magnet 6 Bracket 7 Housing 8 Bearing sleeve 8a1, 8a2 Dynamic pressure groove 8c1 Dynamic pressure groove 9 Seal member S Seal space R1, R2 Radial bearing part T1, T2 Thrust bearing Part
Claims (8)
前記軸受スリーブが、Ｃｕ粉末と、８．０×１０-6／℃以下の線膨張係数を示す金属粉末とを含む混合金属粉末を圧縮成形した後、焼結して得られたものであることを特徴とする流体軸受装置。 In a hydrodynamic bearing device including a shaft member and a bearing sleeve that rotatably supports the shaft member,
The bearing sleeve is obtained by compressing and molding a mixed metal powder containing Cu powder and a metal powder having a linear expansion coefficient of 8.0 × 10 −6 / ° C. or less. A hydrodynamic bearing device.
Priority Applications (6)
| Application Number | Priority Date | Filing Date | Title |
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| JP2005000969A JP4954478B2 (en) | 2005-01-05 | 2005-01-05 | Hydrodynamic bearing device |
| CN201210052284.XA CN102588428B (en) | 2005-01-05 | 2005-12-27 | Fluid lubrication bearing device and motor having the same |
| PCT/JP2005/023897 WO2006073090A1 (en) | 2005-01-05 | 2005-12-27 | Sintered metallic material, oil-retaining bearing constituted of the metallic material, and fluid bearing apparatus |
| CN2005800442241A CN101087669B (en) | 2005-01-05 | 2005-12-27 | Sintered oil-retaining bearing and fluid lubrication bearing device |
| US11/719,809 US20090142010A1 (en) | 2005-01-05 | 2005-12-27 | Sintered metal material, sintered oil-impregnated bearing formed of the metal material, and fluid lubrication bearing device |
| KR1020077012362A KR101339745B1 (en) | 2005-01-05 | 2005-12-27 | Sintered metallic material, oil-retaining bearing constituted of the metallic material, and fluid bearing apparatus |
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| JP2005000969A JP4954478B2 (en) | 2005-01-05 | 2005-01-05 | Hydrodynamic bearing device |
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| JP4954478B2 JP4954478B2 (en) | 2012-06-13 |
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| JP2001073099A (en) * | 1999-08-31 | 2001-03-21 | Eagle Ind Co Ltd | Sintered alloy and bearing material |
| JP2001123253A (en) * | 1999-10-28 | 2001-05-08 | Oiles Ind Co Ltd | Ferrous sintered sliding member and producing method therefor |
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| CN1018657B (en) * | 1991-04-12 | 1992-10-14 | 冶金工业部钢铁研究总院 | Heat-resistant antifriction self-lubricating material and its manufacturing method |
| CN1040572C (en) * | 1992-10-31 | 1998-11-04 | 中南工业大学 | Booster thrust bearing produced by powder metallurgy process |
| JP3942482B2 (en) * | 2001-06-27 | 2007-07-11 | 日本電産株式会社 | DYNAMIC PRESSURE BEARING DEVICE AND MOTOR HAVING THE SAME |
| CN1210486C (en) * | 2003-03-21 | 2005-07-13 | 江汉石油钻头股份有限公司 | Bearing slip-in material and making method |
-
2005
- 2005-01-05 JP JP2005000969A patent/JP4954478B2/en not_active Expired - Fee Related
- 2005-12-27 CN CN2005800442241A patent/CN101087669B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08295902A (en) * | 1995-04-25 | 1996-11-12 | Sankyo Seiki Mfg Co Ltd | Sintering composite powder material and sintered bearing using the material |
| JP2000192960A (en) * | 1999-01-04 | 2000-07-11 | Sankyo Seiki Mfg Co Ltd | Bearing device |
| JP2001073099A (en) * | 1999-08-31 | 2001-03-21 | Eagle Ind Co Ltd | Sintered alloy and bearing material |
| JP2001123253A (en) * | 1999-10-28 | 2001-05-08 | Oiles Ind Co Ltd | Ferrous sintered sliding member and producing method therefor |
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9316253B2 (en) | 2008-02-21 | 2016-04-19 | Ntn Corporation | Sintered bearing |
| US8992658B2 (en) | 2009-03-19 | 2015-03-31 | Ntn Corporation | Sintered metallic bearing and fluid dynamic bearing device equipped with the bearing |
| JP2010223246A (en) * | 2009-03-19 | 2010-10-07 | Ntn Corp | Sintered metal bearing |
| WO2010106909A1 (en) * | 2009-03-19 | 2010-09-23 | Ntn株式会社 | Sintered metallic bearing and fluid dynamic bearing device equipped with the bearing |
| JP2011033156A (en) * | 2009-08-04 | 2011-02-17 | Ntn Corp | Sintered metal bearing and method of manufacturing the same |
| US9154012B2 (en) | 2010-03-29 | 2015-10-06 | Ntn Corporation | Fluid dynamic bearing device and assembly method for same |
| WO2011122556A1 (en) * | 2010-03-29 | 2011-10-06 | Ntn株式会社 | Fluid dynamic bearing unit and assembly method for same |
| JP2011231874A (en) * | 2010-04-28 | 2011-11-17 | Ntn Corp | Fluid dynamic bearing unit and assembly method for the same |
| WO2012043575A1 (en) * | 2010-09-28 | 2012-04-05 | Ntn株式会社 | Fluid dynamic bearing device and assembly method thereof |
| JP2012177467A (en) * | 2011-02-01 | 2012-09-13 | Ntn Corp | Fluid dynamic bearing device |
| CN103447522A (en) * | 2013-08-14 | 2013-12-18 | 上海永进轴承制造有限公司 | Bearing ferrule material and preparation method thereof |
| EP3334020A4 (en) * | 2015-08-04 | 2019-04-10 | Mitsumi Electric Co., Ltd. | Actuator and electric beauty device |
| US10715022B2 (en) | 2015-08-04 | 2020-07-14 | Mitsumi Electric Co., Ltd. | Actuator and electric beauty device |
Also Published As
| Publication number | Publication date |
|---|---|
| CN101087669B (en) | 2012-05-02 |
| CN101087669A (en) | 2007-12-12 |
| JP4954478B2 (en) | 2012-06-13 |
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