JP2001254731A - Dynamic pressure hydraulic bearing, and motor provided therewith - Google Patents
Dynamic pressure hydraulic bearing, and motor provided therewithInfo
- Publication number
- JP2001254731A JP2001254731A JP2000069488A JP2000069488A JP2001254731A JP 2001254731 A JP2001254731 A JP 2001254731A JP 2000069488 A JP2000069488 A JP 2000069488A JP 2000069488 A JP2000069488 A JP 2000069488A JP 2001254731 A JP2001254731 A JP 2001254731A
- Authority
- JP
- Japan
- Prior art keywords
- shaft member
- bearing sleeve
- linear expansion
- expansion coefficient
- thermal expansion
- 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.)
- Withdrawn
Links
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、流体の圧力を利用
してロータを回転自在に支持する動圧流体軸受及びこれ
を備えたモータに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrodynamic bearing for rotatably supporting a rotor by utilizing the pressure of a fluid, and a motor having the same.
【０００２】[0002]
【従来の技術】記録媒体の駆動に用いられるスピンドル
モータ、回転多面鏡を回転駆動するために用いられるス
キャナ用モータ、各種ＯＡ機器に用いられるモータで
は、軸受として流体の圧力を利用した動圧流体軸受を備
えたものが提案され実用に供されている。このようなモ
ータに適用される動圧流体軸受は、例えばラジアル動圧
流体軸受の場合、軸受スリーブと、この軸受スリーブと
相互に相対回転自在な軸部材と、これらの間に規定され
る間隙に充填された潤滑流体（例えば潤滑油）とを具備
し、軸受スリーブと軸部材との相対回転によって潤滑流
体中にラジアル方向の荷重を支持するための荷重支持圧
を発生する動圧発生用溝が例えば軸受スリーブの内周面
に形成されて構成される。2. Description of the Related Art In a spindle motor used for driving a recording medium, a scanner motor used for driving a rotating polygon mirror, and a motor used for various OA equipment, a hydrodynamic fluid using a fluid pressure as a bearing is used. A bearing with a bearing has been proposed and put to practical use. For example, in the case of a radial hydrodynamic bearing, a hydrodynamic bearing applied to such a motor includes a bearing sleeve, a shaft member rotatable relative to the bearing sleeve, and a gap defined therebetween. A dynamic pressure generating groove that includes a filled lubricating fluid (for example, lubricating oil) and generates a load supporting pressure for supporting a radial load in the lubricating fluid by the relative rotation of the bearing sleeve and the shaft member. For example, it is formed on the inner peripheral surface of the bearing sleeve.
【０００３】この動圧流体軸受をモータに適用する場
合、軸固定型モータでは、動圧流体軸受の軸部材が、ス
テータが装着された静止部材に取り付けられ、軸受スリ
ーブが、ロータマグネットが装着されたロータに取り付
けられ、また軸回転型モータでは、動圧流体軸受の軸部
材が上記ロータに取り付けられ、軸受スリーブが静止部
材に取り付けられる。When this hydrodynamic bearing is applied to a motor, in a fixed shaft type motor, a shaft member of the hydrodynamic bearing is mounted on a stationary member on which a stator is mounted, and a bearing sleeve is mounted on a rotor magnet. In a rotary shaft type motor, a shaft member of a hydrodynamic bearing is mounted on the rotor, and a bearing sleeve is mounted on a stationary member.
【０００４】[0004]
【発明が解決しようとする課題】このような動圧流体軸
受を備えたモータでは、使用する環境温度によってモー
タの特性が大きく変化するという問題がある。即ち、動
圧流体軸受で用いる潤滑流体は、温度が低い環境では粘
性が大きく、温度が高い環境では粘性が小さい特性を有
し、このことに起因して、次の通りの問題がある。潤滑
流体の粘性が大きいと、モータの軸受剛性が大きくなる
が、モータの抵抗損失が大きくなって、消費電力が大き
くなるとともにモータの起動特性も悪くなる。これに対
し、潤滑流体の粘性が小さいと、モータの抵抗損失が小
さくなって消費電力が小さくなるが、モータの軸受剛性
が低下してロータを軸倒れなく高精度に回転駆動するこ
とが困難となる。このように使用する温度によってモー
タの特性が大きく変動するので、起動時から定常運転時
にわたってモータを高精度に回転駆動することがことが
難しく、特に高精密モータ、例えばＨＤＤ用スピンドル
モータ、スキャナ用モータ等では記録媒体、多面鏡等を
安定して回転駆動することができないという問題があ
る。A motor provided with such a hydrodynamic bearing has a problem that the characteristics of the motor greatly change depending on the environmental temperature used. That is, the lubricating fluid used in the hydrodynamic bearing has a property that the viscosity is large in a low-temperature environment and is small in a high-temperature environment. This causes the following problem. If the viscosity of the lubricating fluid is high, the bearing rigidity of the motor increases, but the resistance loss of the motor increases, the power consumption increases, and the starting characteristics of the motor deteriorate. On the other hand, if the viscosity of the lubricating fluid is small, the resistance loss of the motor is reduced and the power consumption is reduced.However, it is difficult to rotate the rotor with high accuracy without falling down the shaft of the motor and the rotor rigidity. Become. Since the characteristics of the motor fluctuate greatly depending on the temperature used in this manner, it is difficult to rotate the motor with high accuracy from the time of starting to the time of steady operation, and particularly high precision motors, such as HDD spindle motors and scanners There is a problem that a motor or the like cannot stably rotate a recording medium, a polygon mirror, or the like.
【０００５】本発明の目的は、温度による特性の変動を
抑え、所定の軸受特性を維持することができる動圧流体
軸受を提供することである。本発明の他の目的は、温度
変化によるモータ特性の変動を少なくし、軸倒れを抑え
てロータを高精度に回転駆動することができるモータを
提供することである。An object of the present invention is to provide a hydrodynamic bearing capable of suppressing fluctuations in characteristics due to temperature and maintaining predetermined bearing characteristics. Another object of the present invention is to provide a motor capable of reducing fluctuations in motor characteristics due to a temperature change, suppressing shaft tilt, and driving the rotor to rotate with high precision.
【０００６】[0006]
【課題を解決するための手段】本発明は、軸受スリーブ
と、この軸受スリーブと間隙を介して対向し且つ相互に
相対回転自在である軸部材と、前記軸受スリーブと前記
軸部材との間の間隙に充填された潤滑流体と、前記軸受
スリーブと前記軸部材との相対回転を支持するために前
記潤滑流体中に動圧を発生させる動圧発生用溝と、を具
備する動圧流体軸受において、前記軸部材の内部には、
前記軸部材の線膨張係数と異なる線膨張係数を有する熱
膨張調整部材が配設され、温度変化時に前記熱膨張調整
部材が熱膨張することによって前記軸受スリーブと前記
軸部材との間の間隙長が調整されることを特徴とする。SUMMARY OF THE INVENTION The present invention provides a bearing sleeve, a shaft member opposed to the bearing sleeve via a gap, and rotatable relative to each other, and a shaft member between the bearing sleeve and the shaft member. A hydrodynamic fluid bearing comprising: a lubricating fluid filled in a gap; and a dynamic pressure generating groove for generating a dynamic pressure in the lubricating fluid to support relative rotation between the bearing sleeve and the shaft member. , Inside the shaft member,
A thermal expansion adjusting member having a linear expansion coefficient different from the linear expansion coefficient of the shaft member is provided, and a gap length between the bearing sleeve and the shaft member due to thermal expansion of the thermal expansion adjusting member when a temperature changes. Is adjusted.
【０００７】また、本発明は、静止部材と、前記静止部
材に対して相対的に回転自在であるロータと、前記静止
部材と前記ロータとの間に介在された動圧流体軸受と、
前記静止部材に取り付けられたステータと、前記ステー
タに対向して前記ロータに装着されたロータマグネット
と、を備え、前記動圧流体軸受は、軸受スリーブと、こ
の軸受スリーブと間隙を介して対向し且つ相互に相対回
転自在である軸部材と、前記軸受スリーブと前記軸部材
との間の間隙に充填された潤滑流体と、前記軸受スリー
ブと前記軸部材との相対回転を支持するために前記潤滑
流体中に動圧を発生させる動圧発生用溝と、を具備し、
前記軸受スリーブ及び前記軸部材のいずれか一方が前記
静止部材に装着され、それらの他方がロータに装着され
たモータにおいて、前記軸部材の内部には、前記軸部材
の線膨張係数と異なる線膨張係数を有する熱膨張調整部
材が配設され、温度変化時に前記熱膨張調整部材が熱膨
張することによって前記軸受スリーブと前記軸部材との
間の間隙長が調整されることを特徴とする。Further, the present invention provides a stationary member, a rotor rotatable relative to the stationary member, a hydrodynamic bearing interposed between the stationary member and the rotor,
A stator mounted on the stationary member, and a rotor magnet mounted on the rotor so as to face the stator, wherein the hydrodynamic bearing opposes the bearing sleeve via a gap with the bearing sleeve. A shaft member rotatable relative to each other, a lubricating fluid filled in a gap between the bearing sleeve and the shaft member, and a lubricating fluid for supporting relative rotation between the bearing sleeve and the shaft member. A dynamic pressure generation groove for generating dynamic pressure in the fluid,
In a motor in which one of the bearing sleeve and the shaft member is mounted on the stationary member and the other is mounted on a rotor, a linear expansion coefficient different from a linear expansion coefficient of the shaft member is provided inside the shaft member. A thermal expansion adjusting member having a coefficient is provided, and the gap length between the bearing sleeve and the shaft member is adjusted by thermally expanding the thermal expansion adjusting member when the temperature changes.
【０００８】本発明の動圧流体軸受及びこれを備えたモ
ータにおいては、動圧流体軸受の軸部材の内部に熱膨張
調整部材が設けられ、この熱膨張調整部材は軸部材と異
なる線膨張係数を有する材料から形成される。環境温度
が上昇すると、動圧流体軸受の潤滑流体の粘性が小さく
なり、動圧流体軸受（これを備えたモータ）の剛性が低
下する傾向にある。一方、このように温度が上昇する
と、熱膨張調整部材の熱膨張によって、軸受スリーブと
軸部材との間の間隙が調整され、潤滑流体の粘性低下に
伴う軸受剛性低下、軸倒れを抑え、軸部材（ロータ）を
安定して高精度に回転自在に支持することができる。熱
膨張調整部材の線膨張係数が軸部材の線膨張係数より大
きい場合、温度上昇に伴って熱膨張部材の熱膨張量が軸
部材の熱膨張量よりも大きくなり、この熱膨張調整部材
によって、軸部材の熱膨張量が大きくなる方向に補正さ
れる。一方、熱膨張調整部材の線膨張係数が軸部材の線
膨張係数よりも小さい場合、温度上昇に伴って熱膨張調
整部材の熱膨張量が軸部材の熱膨張量よりも小さくな
り、軸部材の熱膨張量が小さくなる方向に補正される。
尚、潤滑流体として、油、磁性流体、空気等が用いられ
る。In the hydrodynamic bearing of the present invention and the motor having the same, a thermal expansion adjusting member is provided inside the shaft member of the hydrodynamic bearing, and the thermal expansion adjusting member has a different linear expansion coefficient from the shaft member. It is formed from a material having When the environmental temperature rises, the viscosity of the lubricating fluid of the hydrodynamic bearing decreases, and the rigidity of the hydrodynamic bearing (motor provided with the same) tends to decrease. On the other hand, when the temperature rises as described above, the gap between the bearing sleeve and the shaft member is adjusted by the thermal expansion of the thermal expansion adjusting member, thereby suppressing the reduction in bearing rigidity and the shaft falling due to the decrease in the viscosity of the lubricating fluid. The member (rotor) can be stably and rotatably supported with high precision. When the linear expansion coefficient of the thermal expansion adjustment member is larger than the linear expansion coefficient of the shaft member, the amount of thermal expansion of the thermal expansion member becomes larger than the amount of thermal expansion of the shaft member as the temperature rises. The correction is made in the direction in which the amount of thermal expansion of the shaft member increases. On the other hand, if the coefficient of linear expansion of the thermal expansion adjusting member is smaller than the coefficient of linear expansion of the shaft member, the amount of thermal expansion of the thermal expansion adjusting member becomes smaller than the amount of thermal expansion of the shaft member as the temperature rises. The correction is made in the direction in which the amount of thermal expansion decreases.
Oil, magnetic fluid, air and the like are used as the lubricating fluid.
【０００９】また、本発明の動圧流体軸受及びこれを備
えたモータでは、前記軸受スリーブの線膨張係数は前記
軸部材の線膨張係数よりも大きく、前記熱膨張調整部材
の線膨張係数は前記軸受スリーブの線膨張係数よりも大
きいことを特徴とする。本発明の動圧流体軸受及びこれ
を備えたモータにおいては、軸受スリーブは軸部材より
も線膨張係数が大きい材料から形成され、熱膨張調整部
材は軸受スリーブよりも線膨張係数が大きい材料から形
成される。従って、温度が上昇すると、軸部材及び軸受
スリーブの間隙が大きくなる傾向にあるが、熱膨張調整
部材の膨張量が最も大きいので、この熱膨張調整部材に
よって軸部材の膨張量が補正されて軸部材及び軸受スリ
ーブの間隙が小さくなる方向に調整され、これによっ
て、温度上昇に伴う動圧流軸受（モータ）の剛性低下を
抑えることができる。このような一例として、軸部材が
ステンレス鋼（ＳＵＳ３０４）、軸受スリーブが黄銅、
また熱膨張調整部材がアルミニウム合金から形成され
る。Further, in the hydrodynamic bearing of the present invention and the motor including the same, the linear expansion coefficient of the bearing sleeve is larger than the linear expansion coefficient of the shaft member, and the linear expansion coefficient of the thermal expansion adjusting member is the same. It is characterized by being larger than the linear expansion coefficient of the bearing sleeve. In the hydrodynamic bearing of the present invention and the motor having the same, the bearing sleeve is formed from a material having a larger linear expansion coefficient than the shaft member, and the thermal expansion adjusting member is formed from a material having a larger linear expansion coefficient than the bearing sleeve. Is done. Therefore, when the temperature rises, the gap between the shaft member and the bearing sleeve tends to increase. However, since the expansion amount of the thermal expansion adjusting member is the largest, the expansion amount of the shaft member is corrected by this thermal expansion adjusting member, and the shaft expansion amount is corrected. The gap between the member and the bearing sleeve is adjusted so as to be reduced, whereby a decrease in rigidity of the dynamic pressure flow bearing (motor) due to a rise in temperature can be suppressed. For example, the shaft member is made of stainless steel (SUS304), the bearing sleeve is made of brass,
The thermal expansion adjusting member is formed from an aluminum alloy.
【００１０】また、本発明の動圧流体軸受及びこれを備
えたモータでは、前記軸部材の線膨張係数は前記軸受ス
リーブの線膨張係数よりも大きく、前記熱膨張調整部材
の線膨張係数は前記軸部材の線膨張係数よりも小さいこ
とを特徴とする。本発明の動圧流体軸受及びこれを備え
たモータにおいては、軸部材は軸受スリーブよりも線膨
張係数が大きい材料から形成され、熱膨張調整部材は軸
部材よりも線膨張係数が小さい材料から形成される。従
って、温度が上昇すると、軸部材の熱膨張量が軸受スリ
ーブの熱膨張量より大きくなって軸部材と軸受スリーブ
との間の間隙が小さくなる傾向にあるが、熱膨張調整部
材の膨張量が軸部材の膨張量より小さいので、この熱膨
張調整部材によって軸部材の膨張量が小さくなるように
補正され、これによって軸部材及び軸受スリーブとの間
の間隙が大きくなる方向に調整され、これによって、両
者間の間隙が小さくなり過ぎることを防止することがで
きる。Further, in the hydrodynamic bearing of the present invention and the motor having the same, the linear expansion coefficient of the shaft member is larger than the linear expansion coefficient of the bearing sleeve, and the linear expansion coefficient of the thermal expansion adjusting member is It is characterized by being smaller than the linear expansion coefficient of the shaft member. In the hydrodynamic bearing of the present invention and the motor having the same, the shaft member is formed from a material having a larger linear expansion coefficient than the bearing sleeve, and the thermal expansion adjusting member is formed from a material having a smaller linear expansion coefficient than the shaft member. Is done. Therefore, when the temperature rises, the thermal expansion of the shaft member tends to be larger than the thermal expansion of the bearing sleeve, and the gap between the shaft member and the bearing sleeve tends to be smaller. Since the expansion amount of the shaft member is smaller than the expansion amount of the shaft member, the expansion amount of the shaft member is corrected by the thermal expansion adjusting member so as to be reduced, whereby the gap between the shaft member and the bearing sleeve is adjusted in the direction of increasing, and thereby, In addition, it is possible to prevent the gap between them from becoming too small.
【００１１】また、本発明の動圧流体軸受及びこれを備
えたモータでは、前記動圧発生用溝は、前記間隙を規定
する前記軸受スリーブ及び／又は前記軸部材の表面に軸
線方向に離間して一対形成され、前記熱膨張調整部材
は、前記一対の動圧発生用溝の各々に対応する部位に一
対配設されていることを特徴とする。本発明の動圧流体
軸受及びこれを備えたモータにおいては、熱膨張調整部
材が一対の動圧発生用溝の各々に対応する部位に設けら
れるので、動圧発生用溝が設けられた領域における軸受
スリーブと軸部材との間の間隙を調整して軸受剛性の低
下を抑えることができる。In the hydrodynamic bearing of the present invention and the motor having the hydrodynamic bearing, the hydrodynamic groove is axially spaced from the bearing sleeve and / or the surface of the shaft member that defines the gap. And a pair of the thermal expansion adjusting members are provided at portions corresponding to each of the pair of dynamic pressure generating grooves. In the hydrodynamic bearing and the motor including the hydrodynamic bearing of the present invention, since the thermal expansion adjusting member is provided at a portion corresponding to each of the pair of hydrodynamic grooves, the thermal expansion adjusting member is provided in a region where the hydrodynamic groove is provided. By adjusting the gap between the bearing sleeve and the shaft member, it is possible to suppress a decrease in bearing rigidity.
【００１２】更に、本発明の動圧流体軸受及びこれを備
えたモータでは、前記軸部材には、前記軸部材を軸線方
向に貫通する貫通孔が設けられ、前記熱膨張調整部材
は、前記貫通孔内に嵌入されていることを特徴とする。
本発明の動圧流体軸受及びこれを備えたモータにおいて
は、熱膨張調整部材が軸部材の貫通孔内に嵌入されるの
で、比較的簡単に熱膨張調整部材を装着することができ
る。Further, in the hydrodynamic bearing and the motor having the same according to the present invention, the shaft member is provided with a through hole passing through the shaft member in the axial direction, and the thermal expansion adjusting member is provided with the through hole. It is characterized by being fitted in the hole.
In the hydrodynamic bearing of the present invention and the motor including the same, the thermal expansion adjusting member is fitted into the through hole of the shaft member, so that the thermal expansion adjusting member can be mounted relatively easily.
【００１３】[0013]
【発明の実施の形態】以下、添付図面を参照して、本発
明に従う動圧流体軸受及びこれを備えたモータの実施形
態について説明する。図１は、本発明に従う動圧流体軸
受を備えたモータ（本発明のモータでもある）の一実施
形態を示す断面図であり、図２は、図１のモータにおけ
る動圧流体軸受を示す拡大断面図であり、図３は、図２
におけるＩＩＩ−ＩＩＩ線による断面図である。尚、以
下の実施形態においては、ハードディスクの如き記録媒
体を回転駆動するためのスピンドルモータに適用して説
明するが、スキャナ用モータ、各種ＯＡ機器用モータ等
の種々のモータに広く適用することができる。BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a hydrodynamic bearing according to the present invention, and FIG. FIG. 1 is a sectional view showing an embodiment of a motor (also a motor of the present invention) provided with a hydrodynamic bearing according to the present invention, and FIG. 2 is an enlarged view showing the hydrodynamic bearing in the motor of FIG. FIG. 3 is a sectional view, and FIG.
FIG. 3 is a sectional view taken along line III-III in FIG. In the following embodiments, the present invention will be described as applied to a spindle motor for rotating a recording medium such as a hard disk. However, the present invention can be widely applied to various motors such as a motor for a scanner and a motor for various OA devices. it can.
【００１４】図１において、モータの一例としての図示
のスピンドルモータは、静止部材２と、この静止部材２
に対して回転自在であるロータとしてのロータハブ４
と、これら静止部材２とロータハブ４との間に介在され
た動圧流体軸受６とを備えている。図示の形態では、静
止部材２は静止部材本体８を有し、この静止部材本体８
が記録媒体駆動装置のハウジングのベースプレート（図
示せず）に取り付けられる。尚、この静止部材を記録媒
体駆動装置のベースプレートから構成するようにしても
よい。In FIG. 1, a spindle motor shown as an example of a motor includes a stationary member 2 and a stationary member 2.
Hub 4 as a rotor rotatable with respect to
And a hydrodynamic bearing 6 interposed between the stationary member 2 and the rotor hub 4. In the illustrated embodiment, the stationary member 2 has a stationary member body 8,
Is attached to a base plate (not shown) of the housing of the recording medium driving device. The stationary member may be constituted by a base plate of the recording medium driving device.
【００１５】ロータハブ４は、円筒状の周側壁１０及び
この周側壁１０の一端部に設けられた端壁部１２を有す
るハブ本体１４を備えている。ハブ本体１４の周側壁１
０の下端部には半径方向外方に突出する環状フランジ１
６が設けられ、環状フランジ１６にハードディスクの如
き記録媒体（図示せず）が載置される。また、ハブ本体
１４の周側壁１０の内周面には環状ロータマグネット１
８が装着されている。このようなハブ本体１４は、例え
ば鉄、ステンレス鋼等から形成される。The rotor hub 4 has a hub body 14 having a cylindrical peripheral side wall 10 and an end wall portion 12 provided at one end of the peripheral side wall 10. Peripheral side wall 1 of hub body 14
An annular flange 1 protruding outward in the radial direction is provided at the lower end of the cylinder 0.
A recording medium (not shown) such as a hard disk is placed on the annular flange 16. The annular rotor magnet 1 is provided on the inner peripheral surface of the peripheral side wall 10 of the hub body 14.
8 is attached. Such a hub main body 14 is formed of, for example, iron, stainless steel, or the like.
【００１６】図示の動圧流体軸受６は軸部材２０とこの
軸部材２０を相対的に回転自在に支持する軸受スリーブ
２２から構成され、この形態では、軸部材２０の一端部
（図１において下端部）が静止部材本体８に固定されて
いる。軸受スリーブ２２はこの軸部材２０を被嵌し、そ
の端部（図１において上端部）がハブ本体１４の端壁部
１２に固定されている。このように構成されているの
で、ロータハブ４は動圧流体軸受６を介して静止部材２
に回転自在に支持されている。この動圧流体軸受６につ
いては、後に詳述する。The illustrated hydrodynamic bearing 6 is composed of a shaft member 20 and a bearing sleeve 22 for supporting the shaft member 20 so as to be relatively rotatable. In this embodiment, one end of the shaft member 20 (the lower end in FIG. 1) Part) is fixed to the stationary member main body 8. The bearing sleeve 22 is fitted with the shaft member 20, and the end (upper end in FIG. 1) is fixed to the end wall 12 of the hub body 14. With this configuration, the rotor hub 4 is connected to the stationary member 2 via the hydrodynamic bearing 6.
It is supported rotatably. The hydrodynamic bearing 6 will be described later in detail.
【００１７】静止部材本体８には、図１において実質上
垂直上方に延びる円筒状支持壁２４が設けられ、動圧流
体軸受６の軸受スリーブ２２の他端部（図１において下
端部）は円筒状支持壁２４の半径方向内側にて静止部材
本体８に向けて延びている。この円筒状支持壁２４の外
周面には、ロータマグネット１８に対向してステータ２
６が装着されている。ステータ２６は、コアプレートを
積層することによって構成されるステータコア２８と、
このステータコア２８に所要の通りに巻かれたコイル３
０とから構成され、ステータコア２８が円筒状支持壁２
４に外嵌固定される。かく構成されているので、コイル
３０に駆動電流を所要の通りに供給すると、磁化される
ステータコア２８とロータマグネット１８の相互磁気作
用によって、ロータハブ４（これに装着されたされた記
録媒体も一体的に）が所定方向に回転駆動される。The stationary member body 8 is provided with a cylindrical support wall 24 extending substantially vertically upward in FIG. 1, and the other end (the lower end in FIG. 1) of the bearing sleeve 22 of the hydrodynamic bearing 6 is cylindrical. The radially inner side of the support wall 24 extends toward the stationary member body 8. On the outer peripheral surface of the cylindrical support wall 24, the stator 2 faces the rotor magnet 18.
6 is mounted. The stator 26 includes a stator core 28 formed by stacking core plates,
Coil 3 wound as required around stator core 28
0, and the stator core 28 is
4 is externally fixed. When the driving current is supplied to the coil 30 as required, the rotor hub 4 (the recording medium mounted on the rotor hub 4 and the recording medium mounted on the rotor hub 4 are also integrated by the mutual magnetic action of the magnetized stator core 28 and the rotor magnet 18). ) Is driven to rotate in a predetermined direction.
【００１８】次に、図１とともに図２を参照して動圧流
体軸受６について説明すると、図示の軸部材２０は軸部
３２を有し、この軸部３２の一端側部３４及び他端側部
３６はその中央部３８よりも外径が幾分大きく形成され
ている。軸部３２の他端側部３６の外側端部（図１及び
図２において上端部）には、径方向張出部４０を構成す
るスラストプレートが固定されている。この径方向張出
部４０は軸部３２と一体的に設けるようにしてもよい。
また、軸受スリーブ２２の一端側部４２（図１及び図２
において下側部）はその他端側部４４（図１及び図２に
おいて上側部）よりも外径が小さく、この一端側部４２
が円筒状支持壁２４の半径方向内側に位置している。軸
受スリーブ２２の他端側部４４には他端面に開口する収
容凹部４６が設けられ、この収容凹部４６内に軸部材２
０の径方向張出部４０が収容されている。Next, the hydrodynamic bearing 6 will be described with reference to FIG. 2 together with FIG. 1. The illustrated shaft member 20 has a shaft portion 32, and one end 34 and the other end of the shaft 32. The outer diameter of the portion 36 is slightly larger than that of the central portion 38. A thrust plate constituting the radial extension 40 is fixed to the outer end (the upper end in FIGS. 1 and 2) of the other end 36 of the shaft 32. The radial extension 40 may be provided integrally with the shaft 32.
Further, one end 42 of the bearing sleeve 22 (see FIGS. 1 and 2)
In FIG. 1 and FIG. 2, the outer diameter of the lower end is smaller than that of the other end 44 (the upper end in FIGS. 1 and 2).
Are located radially inward of the cylindrical support wall 24. The other end side portion 44 of the bearing sleeve 22 is provided with a housing concave portion 46 which is opened on the other end surface.
Zero radial extension 40 is accommodated.
【００１９】この実施形態では、軸部材２０の軸部３８
及び軸受スリーブ２２に関連して軸方向に離間した一対
のラジアル軸受部４８，５０が設けられている。これら
一対のラジアル軸受部４８，５０に、ラジアル方向の荷
重を支持するための動圧発生手段としてのラジアル動圧
発生用溝５２，５４が設けられており、この形態ではラ
ジアル動圧発生用溝５２，５４が、図１及び図２に破線
で示すように軸受スリーブ２２の内周面に、より具体的
には軸部３２の一端側部３４及び他端側部３６に対向す
る部位に設けられている。これらラジアル動圧発生用溝
５２，５４は、軸受スリーブ２２の内周面に代えて、又
はそれに加えて軸部材２０の軸部３２の外周面に設ける
ようにしてもよい。In this embodiment, the shaft portion 38 of the shaft member 20 is
In addition, a pair of radial bearing portions 48 and 50 that are axially separated from each other in relation to the bearing sleeve 22 are provided. The pair of radial bearing portions 48, 50 are provided with radial dynamic pressure generating grooves 52, 54 as dynamic pressure generating means for supporting a load in the radial direction. In this embodiment, the radial dynamic pressure generating grooves are provided. 52 and 54 are provided on the inner peripheral surface of the bearing sleeve 22 as shown by broken lines in FIGS. 1 and 2, more specifically, at a portion facing the one end 34 and the other end 36 of the shaft 32. Have been. These radial dynamic pressure generating grooves 52 and 54 may be provided on the outer peripheral surface of the shaft portion 32 of the shaft member 20 instead of or in addition to the inner peripheral surface of the bearing sleeve 22.
【００２０】また、軸部材２０の径方向張出部４０及び
軸受スリーブ２２に関連してスラスト軸受部５６が設け
られている。このスラスト軸受部５６には、スラスト方
向の荷重を支持するための動圧発生手段としてスラスト
動圧発生用溝５８が設けられており、この形態では、図
１及び図２に破線で示すように、径方向張出部４０の内
側面に設けられている。このスラスト動圧発生用溝５８
は、軸部材２０の径方向張出部４０に代えて、又はこれ
に加えて軸受スリーブ２２の、上記径方向張出部４０の
内側面に対向する部位に設けるようにしてもよい。A thrust bearing portion 56 is provided in relation to the radially extending portion 40 of the shaft member 20 and the bearing sleeve 22. The thrust bearing portion 56 is provided with a thrust dynamic pressure generating groove 58 as a dynamic pressure generating means for supporting a load in the thrust direction. In this embodiment, as shown by a broken line in FIGS. , Provided on the inner surface of the radially extending portion 40. The thrust dynamic pressure generating groove 58
May be provided instead of, or in addition to, the radial extension 40 of the shaft member 20, at a portion of the bearing sleeve 22 that faces the inner side surface of the radial extension 40.
【００２１】この形態では、潤滑流体としての潤滑油
は、軸部材２０及び軸受スリーブ２２間の間隙の所定領
域に充填されている。即ち、図１及び図２から理解され
るように、潤滑油は、一対のラジアル軸受部４８，５０
のうち静止部材２側に位置する下部ラジアル軸受部４８
が設けられた領域に、またこれと軸方向に離間する上部
ラジアル軸受部５０が設けられた領域からスラスト軸受
部５６が設けられた領域にわたって充填されている。そ
して、このことに関連して、更に次の通りに構成されて
いる。下部ラジアル軸受部４８のラジアル動圧発生用溝
５２は通常のへリングボーン状に形成され、その幅方向
（図１及び図２において上下方向）中央部で流体圧力が
最も高くなるように構成されている。また、上部ラジア
ル軸受部５０のラジアル動圧発生用溝５４は屈曲点が幅
方向中央より図１及び図２において上側（スラスト軸受
部５６側）に偏倚したへリングボーン状に形成され、ま
たスラスト軸受部５６のスラスト動圧発生用溝５８は内
周方向（軸部材２０の軸心方向）に圧力が高くなるスパ
イラル状に形成されており、上部ラジアル軸受部５０の
幅方向中央より上側に偏倚した部分で流体圧力が最も高
くなるように構成されている。In this embodiment, lubricating oil as a lubricating fluid fills a predetermined region of a gap between the shaft member 20 and the bearing sleeve 22. That is, as understood from FIGS. 1 and 2, the lubricating oil is supplied to the pair of radial bearings 48, 50.
Of the lower radial bearing portion 48 located on the stationary member 2 side
Is filled from the region where the upper radial bearing portion 50 which is axially separated from the region where the upper radial bearing portion 50 is provided to the region where the thrust bearing portion 56 is provided. In connection with this, it is further configured as follows. The radial dynamic pressure generating groove 52 of the lower radial bearing portion 48 is formed in a normal herringbone shape, and is configured such that the fluid pressure becomes highest at the center in the width direction (vertical direction in FIGS. 1 and 2). ing. The radial dynamic pressure generating groove 54 of the upper radial bearing portion 50 is formed in a herringbone shape in which a bending point is deviated upward (in the thrust bearing portion 56 side) in FIGS. 1 and 2 from the center in the width direction. The thrust dynamic pressure generating groove 58 of the bearing portion 56 is formed in a spiral shape in which the pressure increases in the inner circumferential direction (the axial direction of the shaft member 20), and is biased upward from the widthwise center of the upper radial bearing portion 50. It is configured such that the fluid pressure is highest in the portion where the fluid pressure is applied.
【００２２】この動圧流体軸受６では、例えば、軸部材
２０（軸部３２及び径方向張出部４０を構成するスラス
トプレート）がステンレス鋼（ＳＵＳ３０４：線膨張係
数α＝１７×１０−６／℃）から形成され、軸受スリー
ブ２２が黄銅（線膨張係数α＝１９×１０−６／℃）か
ら形成される。こうように構成した場合、スピンドルモ
ータの使用環境の温度が上昇する（例えば、記録媒体駆
動装置の使用中の温度が６０℃程度になる）と、軸部材
２０の熱膨張量よりも軸受スリーブ２２の熱膨張量の方
が大きくなる故に、軸部材２０及び軸受スリーブ２２と
の間の間隙が大きくなる傾向にあり、またかかる間隙に
充填される潤滑油は、一般に、温度が上昇すると粘性が
低下する傾向にあり、これらのことに起因して、温度上
昇とともにモータの軸受剛性が低下するが、このモータ
では、これを解消するために、更に次の通りに構成され
ている。In the hydrodynamic bearing 6, for example, the shaft member 20 (the thrust plate forming the shaft portion 32 and the radially extending portion 40) is made of stainless steel (SUS304: linear expansion coefficient α = 17 × 10 −6 /). C.), and the bearing sleeve 22 is formed from brass (linear expansion coefficient α = 19 × 10 −6 / ° C.). In such a configuration, when the temperature of the environment in which the spindle motor is used rises (for example, the temperature during use of the recording medium driving device becomes about 60 ° C.), the amount of thermal expansion of the shaft member 20 exceeds the amount of thermal expansion of the shaft member 20. Since the amount of thermal expansion is larger, the gap between the shaft member 20 and the bearing sleeve 22 tends to increase, and the lubricating oil filled in the gap generally decreases in viscosity as the temperature increases. The bearing stiffness of the motor decreases as the temperature rises due to these factors. However, this motor is further configured as follows to solve the problem.
【００２３】この実施形態では、軸部材２２の軸部３２
に軸線方向に貫通して直線状の貫通孔６２が形成され、
この貫通孔６２の両端部及びその近傍の内径はその中間
部の内径よりも幾分大きく形成され、上記中間部との境
界に段部６４，６６が設けられている。そして、この貫
通孔６２内に一対の熱膨張調整部材６８，７０が例えば
圧入によって嵌入されている。各熱膨張調整部材６８，
７０は幾分外径が大きい頭部７２，７４を有し、かかる
頭部７２，７４が貫通孔６２の段部６４，６６に当接す
るように挿入され、かく当接することによって熱膨張調
整部材６８，７０が軸部材２０の内部の所定位置に位置
付け固定される。In this embodiment, the shaft portion 32 of the shaft member 22
A linear through-hole 62 is formed to penetrate in the axial direction,
The inside diameter of both ends of the through hole 62 and the vicinity thereof is formed somewhat larger than the inside diameter of the middle part, and step portions 64 and 66 are provided at the boundary with the middle part. A pair of thermal expansion adjusting members 68 and 70 are fitted into the through hole 62 by, for example, press fitting. Each thermal expansion adjusting member 68,
Numeral 70 has heads 72 and 74 having somewhat larger outer diameters, and these heads 72 and 74 are inserted so as to abut against the stepped portions 64 and 66 of the through hole 62, and the thermal expansion adjusting member is brought into contact therewith. 68 and 70 are positioned and fixed at predetermined positions inside the shaft member 20.
【００２４】熱膨張調整部材６８，７０は、図１及び図
２に示す通り、一対のラジアル軸受部４８，５０に対応
して配設され、この形態では、各ラジアル動圧発生用溝
５２，５４が形成された領域全体にわたって貫通孔６２
内を延びており、かかるラジアル軸受部４８，５０が設
けられた領域における軸部材２０及び軸受スリーブ２２
の間に規定される間隙の大きさを後述する如く調整す
る。この実施形態では、熱膨張調整部材６８，７０は軸
部材２０よりも線膨張係数が大きい材料から形成され、
このように形成することによって、温度上昇時における
熱膨張調整部材６８，７０の熱膨張量が軸部材２０の熱
膨張量よりも大きくなる。従って、使用環境温度が上昇
したとき、熱膨張調整部材６８，７０の熱膨張によって
軸部材２０の所定部位（ラジアル軸受部４８，５０が設
けられた部位に対応する部位）の外径が更に若干拡径さ
れる。As shown in FIGS. 1 and 2, the thermal expansion adjusting members 68 and 70 are provided corresponding to the pair of radial bearing portions 48 and 50. In this embodiment, the radial dynamic pressure generating grooves 52 and 70 are provided. The through hole 62 extends over the entire area where the
The shaft member 20 and the bearing sleeve 22 extend in the region where the radial bearing portions 48 and 50 are provided.
The size of the gap defined between them is adjusted as described later. In this embodiment, the thermal expansion adjustment members 68 and 70 are formed from a material having a larger linear expansion coefficient than the shaft member 20.
By forming in this manner, the thermal expansion of the thermal expansion adjusting members 68 and 70 when the temperature rises is greater than the thermal expansion of the shaft member 20. Therefore, when the use environment temperature rises, the outer diameter of the predetermined portion of the shaft member 20 (the portion corresponding to the portion where the radial bearing portions 48, 50 are provided) is further slightly increased due to the thermal expansion of the thermal expansion adjusting members 68, 70. The diameter is expanded.
【００２５】この熱膨張調整部材６８，７０は、この実
施形態のように軸受スリーブ２２が軸部材２０よりも線
膨張係数が大きい材料から形成されている場合、この軸
受スリーブよりも更に線膨張係数が大きい材料から形成
するのが望ましく、かく構成することによって、熱膨張
調整部材６８，７０の熱膨張量が軸受スリーブ２２の熱
膨張量よりも更に大きくなり、従って、使用環境温度が
上昇したとき、軸部材２０の所定部位が更に大きく拡径
され、軸部材２０及び軸受スリーブ２２の間隙が小さく
なるように補正することができる。このような熱膨張調
整部材６８，７０は、例えばアルミニウム合金（ＡＡ６
０６１：線膨張係数α＝２４×１０−６／℃）或いはポ
リブチレンテフタレート（ＰＢＴ：線膨張係数α＝９０
×１０− ６／℃）から形成される。図３及び図４を参照
して熱膨張調整部材６８，７０を備えたモータの作用を
更に説明すると、通常の温度環境（例えば室温）では、
軸部材２０の軸部３８の外周面と軸受スリーブ２２の側
部４２内周面との間の間隙は、設計の際に設定された設
計値となり、例えば、図３に示すような状態となり、軸
部材２０及び軸受スリーブ２２のこの間隙に潤滑油が充
填される。When the bearing sleeve 22 is made of a material having a larger linear expansion coefficient than the shaft member 20 as in this embodiment, the thermal expansion adjusting members 68 and 70 have a further linear expansion coefficient than the bearing sleeve. It is preferable that the thermal expansion adjusting members 68 and 70 have a larger thermal expansion amount than the thermal expansion amount of the bearing sleeve 22. Therefore, when the use environment temperature increases, The correction can be made such that the diameter of the predetermined portion of the shaft member 20 is further increased, and the gap between the shaft member 20 and the bearing sleeve 22 is reduced. Such thermal expansion adjusting members 68 and 70 are made of, for example, an aluminum alloy (AA6).
061: linear expansion coefficient α = 24 × 10 −6 / ° C.) or polybutylene terephthalate (PBT: linear expansion coefficient α = 90)
× 10 - 6 / ℃) is formed from. The operation of the motor including the thermal expansion adjusting members 68 and 70 will be further described with reference to FIGS. 3 and 4. In a normal temperature environment (for example, room temperature),
The gap between the outer peripheral surface of the shaft portion 38 of the shaft member 20 and the inner peripheral surface of the side portion 42 of the bearing sleeve 22 has a design value set at the time of design, for example, as shown in FIG. This gap between the shaft member 20 and the bearing sleeve 22 is filled with lubricating oil.
【００２６】熱膨張調整部材６８，７０を備えていない
モータ（従来のスピンドルモータ）において使用環境温
度が上昇すると、図４（ａ）に示すように、軸受スリー
ブ２２の一端側部４２（黄銅から形成される）の熱膨張
が軸部材２０Ａの軸部３８Ａ（ステンレス鋼から形成さ
れている）の熱膨張よりも大きくなり、従って軸部材２
０の軸部３８の外周面と軸受スリーブ２２の側部４２の
内周面との間隙は、通常の温度環境時（図３に示す状
態）よりも大きくなり、このことと潤滑油の粘性低下に
起因してモータの剛性が低下するという問題が生じる。When the ambient temperature rises in a motor (conventional spindle motor) not having the thermal expansion adjusting members 68 and 70, as shown in FIG. 4A, one end 42 of the bearing sleeve 22 (from brass) is used. ) Is greater than the thermal expansion of the shaft portion 38A (formed of stainless steel) of the shaft member 20A, and therefore the shaft member 2
The gap between the outer peripheral surface of the shaft portion 38 and the inner peripheral surface of the side portion 42 of the bearing sleeve 22 is larger than that in a normal temperature environment (the state shown in FIG. 3), which reduces the viscosity of the lubricating oil. This causes a problem that the rigidity of the motor is reduced.
【００２７】これに対して、熱膨張部材６８，７０を備
えた上述したモータでは、使用環境温度が上昇すると、
軸受スリーブ２２の熱膨張が軸部材２０の熱膨張よりも
大きいが、熱膨張調整部材６８，７０の熱膨張が軸受ス
リーブ２２の熱膨張よりも更に大きく、このことに関連
して、熱膨張調整部材６８，７０による熱膨張によって
軸部材２０の軸部３８が径方向に膨張する。このように
軸部材２０が膨張して拡径することによって、図４
（ｂ）に示すように、軸部材２０の軸部３８の外周面と
軸受スリーブ２２の側部４２の内周面との間隙は、図３
に示す通常の温度環境時よりも小さくなる。そして、両
者間の隙間が小さくなることによってモータの軸受剛性
が改善され、温度上昇に伴う潤滑油の粘性低下に起因す
る剛性低下が抑えられ、使用環境温度の影響をほとんど
受けることなくモータの剛性をほぼ一定に保つことがで
きる。On the other hand, in the above-described motor having the thermal expansion members 68 and 70, when the use environment temperature rises,
Although the thermal expansion of the bearing sleeve 22 is greater than the thermal expansion of the shaft member 20, the thermal expansion of the thermal expansion adjusting members 68 and 70 is even greater than the thermal expansion of the bearing sleeve 22. The shaft portion 38 of the shaft member 20 expands in the radial direction due to the thermal expansion by the members 68 and 70. As the shaft member 20 expands and expands in diameter in this manner, FIG.
As shown in FIG. 3B, the gap between the outer peripheral surface of the shaft portion 38 of the shaft member 20 and the inner peripheral surface of the side portion 42 of the bearing sleeve 22 is as shown in FIG.
Is smaller than in the normal temperature environment shown in FIG. By reducing the gap between the two, the bearing stiffness of the motor is improved, and the decrease in stiffness caused by the decrease in the viscosity of the lubricating oil due to the temperature rise is suppressed. Can be kept almost constant.
【００２８】以上、本発明に従う動圧流体軸受及びこれ
を備えたモータの実施形態について説明したが、本発明
はかかる実施形態に限定されるものではなく、本発明の
範囲を逸脱することなく種々の変形乃至修正が可能であ
る。例えば、図示の実施形態では、軸部材２０の貫通孔
６２内に一対の熱膨張調整部材６８，７０を嵌入してい
るが、これに代えて、一つの長い熱膨張調整部材を貫通
孔６２の一端部から他端部にわたって嵌入するようにし
てもよい。また、このような構成に代えて、例えば軸部
材２０の両端部にそれぞれ端面から軸線方向に延びる装
着凹部を設け、かかる装着凹部に熱膨張調整部材６８，
７０を嵌入するようにしてもよく、熱膨張調整部材６
８，７０を必要箇所に配置するようにしればよい。The embodiments of the hydrodynamic bearing and the motor provided with the same according to the present invention have been described above. However, the present invention is not limited to such an embodiment, and various modifications can be made without departing from the scope of the present invention. Can be modified or modified. For example, in the illustrated embodiment, a pair of thermal expansion adjusting members 68 and 70 are fitted into the through hole 62 of the shaft member 20, but instead, one long thermal expansion adjusting member is inserted into the through hole 62. You may make it fit from one end to the other end. Instead of such a configuration, for example, mounting recesses extending in the axial direction from the end faces are provided at both ends of the shaft member 20, and the thermal expansion adjusting members 68 and 68 are provided in the mounting recesses.
70 may be fitted, and the thermal expansion adjusting member 6
What is necessary is just to arrange | position 8,70 in a required place.
【００２９】また、図示の実施形態では、熱膨張調整部
材６８，７０をラジアル軸受部４８，５０に対応した部
位に配置しているが、必ずしもこのような部位に設ける
必要はなく、ラジアル軸受部４８，５０からはずれた部
位に配置するようにしてもよい。この場合、温度変化時
に熱膨張調整部材が配置された部位が若干拡径して軸部
材２０の外周面が傾斜するようになり、これによって軸
受スリーブ２２の内周面に発生する傾きを吸収して、軸
部材の外周面と軸受スリーブの内周面とを実質上平行に
保つことができる。Further, in the illustrated embodiment, the thermal expansion adjusting members 68 and 70 are arranged at portions corresponding to the radial bearing portions 48 and 50, however, it is not always necessary to provide them at such portions. It may be arranged at a position deviating from 48, 50. In this case, when the temperature changes, the portion where the thermal expansion adjusting member is disposed slightly increases in diameter, so that the outer peripheral surface of the shaft member 20 becomes inclined, thereby absorbing the inclination generated on the inner peripheral surface of the bearing sleeve 22. Thus, the outer peripheral surface of the shaft member and the inner peripheral surface of the bearing sleeve can be kept substantially parallel.
【００３０】また、図示の実施形態では、熱膨張調整部
材６８，７０を軸部材２０の線膨張係数よりも大きい材
料から形成しているが、次のように構成した場合、熱膨
張調整部材を軸部材の線膨張係数よりも小さい材料から
形成するのが望ましい。例えば、軸受スリーブをセラミ
ック（線膨張係数α＝３×１０−６／℃）から形成し、
軸部材を金属（線膨張係数α＝１０〜×１０−６／℃）
から形成した場合、温度が上昇すると、軸部材の熱膨張
量が軸受スリーブの熱膨張量よりも大きくなり、軸受ス
リーブと軸部材との間の間隙が小さくなる傾向にあり、
場合によっては係る間隙が小さくなりすぎて軸受剛性が
大きく変動することがある。このような場合、熱膨張調
整部材の線膨張係数が軸部材の線膨張係数よりも小さい
と、環境温度が上昇（又は低下）するに伴って、軸部材
と熱膨張調整部材の間の面圧（接触圧力）が低下（又は
上昇）し、軸部材の熱膨張量は、熱膨張調整部材によっ
て径方向の膨張量が小さく（又は大きく）なる方向に補
正される。かくして、軸受スリーブと軸部材との間の間
隙が大きく（又は小さく）なる方向に調整され、熱膨張
調整部材によって軸部材の熱膨張量を補正し、両者間の
隙間を所要の通りに調整することができる。Further, in the illustrated embodiment, the thermal expansion adjusting members 68 and 70 are formed from a material having a larger linear expansion coefficient than the shaft member 20. It is desirable to form the shaft member from a material having a smaller coefficient of linear expansion. For example, the bearing sleeve is formed from ceramic (linear expansion coefficient α = 3 × 10 −6 / ° C.),
The shaft member is made of metal (linear expansion coefficient α = 10 to 10-6 / C)
When formed from, when the temperature rises, the amount of thermal expansion of the shaft member becomes larger than the amount of thermal expansion of the bearing sleeve, and the gap between the bearing sleeve and the shaft member tends to decrease,
In some cases, the gap becomes too small and the bearing rigidity may fluctuate greatly. In such a case, if the linear expansion coefficient of the thermal expansion adjusting member is smaller than the linear expansion coefficient of the shaft member, the surface pressure between the shaft member and the thermal expansion adjusting member is increased as the environmental temperature increases (or decreases). (Contact pressure) decreases (or increases), and the thermal expansion amount of the shaft member is corrected by the thermal expansion adjusting member in a direction in which the radial expansion amount decreases (or increases). Thus, the gap between the bearing sleeve and the shaft member is adjusted to be larger (or smaller), the thermal expansion amount of the shaft member is corrected by the thermal expansion adjusting member, and the gap therebetween is adjusted as required. be able to.
【００３１】また、例えば、図示の実施形態では、軸部
材２０を静止部材２に固定するとともに軸受スリーブ２
２をロータハブ４に固定する軸固定型のモータに適用し
て説明したが、これに限定されず、軸部材２０をロータ
ハブ４に固定するとともに軸受スリーブ２２を静止部材
２に固定する軸回転型のモータにも同様に適用すること
ができる。更に、図示の実施形態では、潤滑流体として
油（オイル）を用いるものに適用して説明したが、潤滑
流体として磁性流体、空気等を用いるものにも同様に適
用することができる。For example, in the illustrated embodiment, the shaft member 20 is fixed to the stationary member 2 and the bearing sleeve 2 is fixed.
2 has been described as being applied to a fixed shaft type motor that is fixed to the rotor hub 4. However, the present invention is not limited to this, and a shaft rotating type motor that fixes the shaft member 20 to the rotor hub 4 and fixes the bearing sleeve 22 to the stationary member 2. The same can be applied to a motor. Further, in the illustrated embodiment, the present invention has been described as applied to the case where oil (oil) is used as the lubricating fluid. However, the present invention can be similarly applied to the case where a magnetic fluid, air or the like is used as the lubricating fluid.
【００３２】[0032]
【発明の効果】本発明の請求項１の動圧流体軸受及び請
求項６のモータによれば、本発明の動圧流体軸受及びこ
れを備えたモータにおいては、動圧流体軸受の軸部材の
内部に熱膨張調整部材が設けられ、この熱膨張調整部材
の線膨張係数が軸部材の線膨張係数と異なっているの
で、温度が上昇すると、熱膨張調整部材の熱膨張によっ
て、軸受スリーブと軸部材との間の間隙が調整され、潤
滑流体の粘性低下に伴う軸受剛性低下、軸倒れを抑え、
軸部材（ロータ）を安定して高精度に回転自在に支持す
ることができる。According to the hydrodynamic bearing of the first aspect of the present invention and the motor of the sixth aspect, in the hydrodynamic bearing of the present invention and the motor having the same, the shaft member of the hydrodynamic bearing is provided. A thermal expansion adjusting member is provided inside, and the linear expansion coefficient of the thermal expansion adjusting member is different from the linear expansion coefficient of the shaft member. Therefore, when the temperature rises, the thermal expansion of the thermal expansion adjusting member causes the bearing sleeve and the shaft to expand. The gap between the members has been adjusted to reduce bearing rigidity and shaft fall due to the decrease in viscosity of the lubricating fluid.
The shaft member (rotor) can be stably rotatably supported with high precision.
【００３３】また、本発明の請求項２の動圧流体軸受及
び請求項７のモータによれば、熱膨張調整部材の膨張量
が最も大きいので、温度が上昇すると、この熱膨張調整
部材によって軸部材の膨張量が大きくなる方向に補正さ
れて軸部材及び軸受スリーブの間隙が小さくなる方向に
調整され、これによって、温度上昇に伴う動圧流軸受
（モータ）の剛性低下を抑えることができる。According to the hydrodynamic bearing of the second aspect of the present invention and the motor of the seventh aspect, since the thermal expansion adjusting member has the largest expansion amount, when the temperature rises, the shaft is controlled by the thermal expansion adjusting member. The expansion amount of the member is corrected so as to be increased, and the gap between the shaft member and the bearing sleeve is adjusted so as to be reduced, whereby a decrease in rigidity of the dynamic pressure flow bearing (motor) due to a rise in temperature can be suppressed.
【００３４】また、本発明の請求項３の動圧流体軸受及
び請求項８のモータでは、熱膨張調整部材は軸部材より
も線膨張係数が小さい材料から形成されているので、温
度が上昇すると、熱膨張調整部材によって軸部材の膨張
量が小さくなる方向に補正される。軸受スリーブの線膨
張係数が軸部材の線膨張係数より小さい場合、温度上昇
によって両者間の間隙が小さくなり過ぎるときがあり、
このようなときに上述したように軸部材の熱膨張量を補
正することによって、それらの間の間隙を所要の通りに
調整して動圧流体軸受の剛性を一定に保持することがで
きる。また、本発明の請求項４の動圧流体軸受及び請求
項９のモータによれば、熱膨張調整部材が一対の動圧発
生用溝の各々に対応する部位に設けられるので、動圧発
生用溝が設けられた領域における軸受スリーブと軸部材
との間の間隙を調整して軸受剛性の低下を抑えることが
できる。In the hydrodynamic bearing according to the third aspect of the present invention and the motor according to the eighth aspect, since the thermal expansion adjusting member is formed of a material having a smaller linear expansion coefficient than the shaft member, when the temperature rises, The thermal expansion adjusting member corrects the expansion amount of the shaft member in a direction in which the expansion amount decreases. If the coefficient of linear expansion of the bearing sleeve is smaller than the coefficient of linear expansion of the shaft member, the temperature may increase and the gap between the two may become too small,
In such a case, by correcting the amount of thermal expansion of the shaft member as described above, the gap between them can be adjusted as required, and the rigidity of the hydrodynamic bearing can be kept constant. According to the hydrodynamic bearing of claim 4 of the present invention and the motor of claim 9, since the thermal expansion adjusting member is provided at a portion corresponding to each of the pair of dynamic pressure generating grooves, By adjusting the gap between the bearing sleeve and the shaft member in the region where the groove is provided, it is possible to suppress a decrease in bearing rigidity.
【００３５】更に、本発明の請求項５の動圧流体軸受及
び請求項１０のモータみよれば、熱膨張調整部材が軸部
材の貫通孔内に嵌入されるので、比較的簡単に熱膨張調
整部材を装着することができる。Further, according to the hydrodynamic bearing of the present invention, the thermal expansion adjusting member is fitted into the through hole of the shaft member, so that the thermal expansion adjusting member can be relatively easily formed. A member can be mounted.
【図１】本発明に従う動圧流体軸受を備えたモータ（本
発明のモータでもある）の一実施形態を示す断面図であ
る。FIG. 1 is a sectional view showing an embodiment of a motor (also a motor of the present invention) provided with a hydrodynamic bearing according to the present invention.
【図２】図１のモータにおける動圧流体軸受を示す拡大
断面図である。FIG. 2 is an enlarged sectional view showing a hydrodynamic bearing in the motor of FIG.
【図３】図２におけるＩＩＩ−ＩＩＩ線による断面図で
ある。FIG. 3 is a sectional view taken along line III-III in FIG. 2;
【図４】図４（ａ）は、従来のモータにおける温度上昇
時の状態を示す断面図であり、図４（ｂ）は、図１のモ
ータにおける温度上昇時の状態を示す断面図である。FIG. 4A is a cross-sectional view showing a state of the conventional motor when the temperature rises, and FIG. 4B is a cross-sectional view showing a state of the motor of FIG. 1 when the temperature rises. .
２ 静止部材 ４ ロータハブ（ロータ） ６ 動圧流体軸受 １４ ハブ本体 １８ ロータマグネット ２０ 軸部材 ２２ 軸受スリーブ ２６ ステータ ３２ 軸部 ４８，５０ ラジアル軸受部 ５２，５４ 動圧発生用溝 ５６ スラスト軸受部 ６２ 貫通孔 ６８，７０ 熱膨張調整部材 Reference Signs List 2 stationary member 4 rotor hub (rotor) 6 hydrodynamic bearing 14 hub body 18 rotor magnet 20 shaft member 22 bearing sleeve 26 stator 32 shaft portion 48, 50 radial bearing portion 52, 54 dynamic pressure generating groove 56 thrust bearing portion 62 penetration Hole 68, 70 Thermal expansion adjusting member
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ テーマコート゛(参考） Ｈ０２Ｋ 21/22 Ｈ０２Ｋ 21/22 Ｍ Ｆターム(参考） 3J011 AA08 AA11 BA02 CA02 JA02 KA02 KA04 MA12 QA01 RA01 SB01 3J012 AB04 AB11 BB01 BB03 BB05 CB10 FB01 5H605 BB05 BB14 BB19 CC04 CC05 DD09 EB01 EB02 EB21 FF03 FF06 5H607 BB01 BB14 BB17 BB25 CC01 CC05 GG01 GG02 GG12 5H621 GA01 HH01 JK07 JK08 JK17 JK19 ──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. 7 Identification FI theme coat テ ー マ (reference) H02K 21/22 H02K 21/22 MF term (reference) 3J011 AA08 AA11 BA02 CA02 JA02 KA02 KA04 MA12 QA01 RA01 SB01 3J012 AB04 AB11 BB01 BB03 BB05 CB10 FB01 5H605 BB05 BB14 BB19 CC04 CC05 DD09 EB01 EB02 EB21 FF03 FF06 5H607 BB01 BB14 BB17 BB25 CC01 CC05 GG01 GG02 GG12 5H621 GA01 HH01 JK07 JK07 JK17
Claims (10)
隙を介して対向し且つ相互に相対回転自在である軸部材
と、前記軸受スリーブと前記軸部材との間の間隙に充填
された潤滑流体と、前記軸受スリーブと前記軸部材との
相対回転を支持するために前記潤滑流体中に動圧を発生
させる動圧発生用溝と、を具備する動圧流体軸受におい
て、 前記軸部材の内部には、前記軸部材の線膨張係数と異な
る線膨張係数を有する熱膨張調整部材が配設され、温度
変化時に前記熱膨張調整部材が熱膨張することによって
前記軸受スリーブと前記軸部材との間の間隙長が調整さ
れることを特徴とする動圧流体軸受。1. A bearing sleeve, a shaft member facing the bearing sleeve via a gap and being rotatable relative to each other, and a lubricating fluid filled in a gap between the bearing sleeve and the shaft member. A dynamic pressure generating groove for generating a dynamic pressure in the lubricating fluid to support the relative rotation between the bearing sleeve and the shaft member. A thermal expansion adjusting member having a linear expansion coefficient different from the linear expansion coefficient of the shaft member, and the thermal expansion adjusting member thermally expands when a temperature changes, whereby a gap between the bearing sleeve and the shaft member is provided. A hydrodynamic bearing wherein the length is adjusted.
部材の線膨張係数よりも大きく、前記熱膨張調整部材の
線膨張係数は前記軸受スリーブの線膨張係数よりも大き
いことを特徴とする請求項１記載の動圧流体軸受。2. The linear expansion coefficient of the bearing sleeve is larger than the linear expansion coefficient of the shaft member, and the linear expansion coefficient of the thermal expansion adjusting member is larger than the linear expansion coefficient of the bearing sleeve. Item 2. A hydrodynamic bearing according to Item 1.
ーブの線膨張係数よりも大きく、前記熱膨張調整部材の
線膨張係数は前記軸部材の線膨張係数よりも小さいこと
を特徴とする請求項１記載の動圧流体軸受。3. The linear expansion coefficient of the shaft member is larger than the linear expansion coefficient of the bearing sleeve, and the linear expansion coefficient of the thermal expansion adjusting member is smaller than the linear expansion coefficient of the shaft member. Item 2. A hydrodynamic bearing according to Item 1.
る前記軸受スリーブ及び／又は前記軸部材の表面に軸線
方向に離間して一対形成され、前記熱膨張調整部材は、
前記一対の動圧発生用溝の各々に対応する部位に一対配
設されていることを特徴とする請求項１、２又は３のい
ずれかに記載の動圧流体軸受。4. The dynamic pressure generating groove is formed in a pair in the surface of the bearing sleeve and / or the shaft member that defines the gap and is spaced apart in the axial direction.
The hydrodynamic bearing according to any one of claims 1 to 3, wherein a pair of hydrodynamic bearings are provided at positions corresponding to the pair of hydrodynamic grooves.
に貫通する貫通孔が設けられ、前記熱膨張調整部材は、
前記貫通孔内に嵌入されていることを特徴とする請求項
１、２、３又は４のいずれかに記載の動圧流体軸受。5. The shaft member is provided with a through-hole penetrating the shaft member in the axial direction, and the thermal expansion adjusting member is
The hydrodynamic bearing according to claim 1, wherein the hydrodynamic bearing is fitted in the through hole.
的に回転自在であるロータと、前記静止部材と前記ロー
タとの間に介在された動圧流体軸受と、前記静止部材に
取り付けられたステータと、前記ステータに対向して前
記ロータに装着されたロータマグネットと、を備え、 前記動圧流体軸受は、軸受スリーブと、この軸受スリー
ブと間隙を介して対向し且つ相互に相対回転自在である
軸部材と、前記軸受スリーブと前記軸部材との間の間隙
に充填された潤滑流体と、前記軸受スリーブと前記軸部
材との相対回転を支持するために前記潤滑流体中に動圧
を発生させる動圧発生用溝と、を具備し、 前記軸受スリーブ及び前記軸部材のいずれか一方が前記
静止部材に装着され、それらの他方がロータに装着され
たモータにおいて、 前記軸部材の内部には、前記軸部材の線膨張係数と異な
る線膨張係数を有する熱膨張調整部材が配設され、温度
変化時に前記熱膨張調整部材が熱膨張することによって
前記軸受スリーブと前記軸部材との間の間隙長が調整さ
れることを特徴とするモータ。6. A stationary member, a rotor rotatable relative to the stationary member, a hydrodynamic fluid bearing interposed between the stationary member and the rotor, and mounted on the stationary member. And a rotor magnet mounted on the rotor so as to face the stator, wherein the hydrodynamic bearing opposes a bearing sleeve via a gap and is relatively rotatable relative to each other. A shaft member, a lubricating fluid filled in a gap between the bearing sleeve and the shaft member, and a dynamic pressure in the lubricating fluid to support relative rotation between the bearing sleeve and the shaft member. A groove for generating a dynamic pressure to be generated, wherein one of the bearing sleeve and the shaft member is mounted on the stationary member, and the other is mounted on the rotor. Inside, a thermal expansion adjusting member having a linear expansion coefficient different from the linear expansion coefficient of the shaft member is provided, and the thermal expansion adjusting member thermally expands at the time of a temperature change, so that the bearing sleeve and the shaft member can be connected to each other. A motor wherein a gap length between the motors is adjusted.
部材の線膨張係数よりも大きく、前記熱膨張調整部材の
線膨張係数は前記軸受スリーブの線膨張係数よりも大き
いことを特徴とする請求項６記載のモータ。7. A linear expansion coefficient of the bearing sleeve is larger than a linear expansion coefficient of the shaft member, and a linear expansion coefficient of the thermal expansion adjusting member is larger than a linear expansion coefficient of the bearing sleeve. Item 6. The motor according to Item 6.
ーブの線膨張係数よりも大きく、前記熱膨張調整部材の
線膨張係数は前記軸部材の線膨張係数よりも小さいこと
を特徴とする請求項６記載のモータ。8. The linear expansion coefficient of the shaft member is larger than the linear expansion coefficient of the bearing sleeve, and the linear expansion coefficient of the thermal expansion adjusting member is smaller than the linear expansion coefficient of the shaft member. Item 6. The motor according to Item 6.
る前記軸受スリーブ及び／又は前記軸部材の表面に軸線
方向に離間して一対形成され、前記熱膨張調整部材は、
前記一対の動圧発生用溝の各々に対応する部位に一対配
設されていることを特徴とする請求項６、７又は８のい
ずれかに記載のモータ。9. The dynamic pressure generating groove is formed in a pair in the surface of the bearing sleeve and / or the shaft member that defines the gap and is spaced apart in the axial direction.
9. The motor according to claim 6, wherein a pair of the dynamic pressure generating grooves are provided at portions corresponding to each of the pair of dynamic pressure generating grooves.
向に貫通する貫通孔が設けられ、前記熱膨張調整部材
は、前記貫通孔内に嵌入されていることを特徴とする請
求項６、７、８又は９のいずれかに記載のモータ。10. The shaft member is provided with a through hole passing through the shaft member in the axial direction, and the thermal expansion adjusting member is fitted in the through hole. , 7, 8 or 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000069488A JP2001254731A (en) | 2000-03-13 | 2000-03-13 | Dynamic pressure hydraulic bearing, and motor provided therewith |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000069488A JP2001254731A (en) | 2000-03-13 | 2000-03-13 | Dynamic pressure hydraulic bearing, and motor provided therewith |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2001254731A true JP2001254731A (en) | 2001-09-21 |
Family
ID=18588351
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2000069488A Withdrawn JP2001254731A (en) | 2000-03-13 | 2000-03-13 | Dynamic pressure hydraulic bearing, and motor provided therewith |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2001254731A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102008017649A1 (en) | 2007-04-04 | 2008-10-30 | Minebea Co., Ltd. | Fluid dynamic radial bearing for rotating rotor relative to stator of spindle motor to drive storage disc drive, has filling material with Young's modulus, thermal expansion coefficient and Poisson ratio for changing diameter of part |
| JP2012197925A (en) * | 2011-03-23 | 2012-10-18 | Mitsubishi Electric Corp | Brake device for electric rotary machine |
| ITFI20130092A1 (en) * | 2013-04-24 | 2014-10-25 | Nuovo Pignone Srl | "ROTATING MACHINERY WITH ADAPTIVE BEARING JOURNALS AND METHODS OF OPERATING" |
-
2000
- 2000-03-13 JP JP2000069488A patent/JP2001254731A/en not_active Withdrawn
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102008017649A1 (en) | 2007-04-04 | 2008-10-30 | Minebea Co., Ltd. | Fluid dynamic radial bearing for rotating rotor relative to stator of spindle motor to drive storage disc drive, has filling material with Young's modulus, thermal expansion coefficient and Poisson ratio for changing diameter of part |
| JP2012197925A (en) * | 2011-03-23 | 2012-10-18 | Mitsubishi Electric Corp | Brake device for electric rotary machine |
| ITFI20130092A1 (en) * | 2013-04-24 | 2014-10-25 | Nuovo Pignone Srl | "ROTATING MACHINERY WITH ADAPTIVE BEARING JOURNALS AND METHODS OF OPERATING" |
| WO2014174013A1 (en) * | 2013-04-24 | 2014-10-30 | Nuovo Pignone Srl | Rotating machinery with adaptive bearing journals and methods of operating |
| CN105358848A (en) * | 2013-04-24 | 2016-02-24 | 诺沃皮尼奥内股份有限公司 | Rotating machinery with adaptive bearing journals and methods of operating |
| JP2016518564A (en) * | 2013-04-24 | 2016-06-23 | ヌオーヴォ ピニォーネ ソチエタ レスポンサビリタ リミタータＮｕｏｖｏ Ｐｉｇｎｏｎｅ Ｓ．Ｒ．Ｌ． | Rotating machine with adaptive bearing journal and method of operation |
| CN105358848B (en) * | 2013-04-24 | 2017-11-17 | 诺沃皮尼奥内股份有限公司 | The rotating machinery and operating method of adaptable bearing journal |
| US9835196B2 (en) | 2013-04-24 | 2017-12-05 | Nuovo Pignone Srl | Rotating machinery with adaptive bearing journals and methods of operating |
| RU2663958C2 (en) * | 2013-04-24 | 2018-08-13 | Нуово Пиньоне СРЛ | Rotating machinery with adaptive bearing journals and methods of operating |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A300 | Withdrawal of application because of no request for examination |
Free format text: JAPANESE INTERMEDIATE CODE: A300 Effective date: 20070605 |