JP6502036B2 - Fluid dynamic bearing device and motor including the same - Google Patents

Description

本発明は、流体動圧軸受装置及びこれを備えるモータに関する。   The present invention relates to a fluid dynamic bearing device and a motor including the same.

周知のように、流体動圧軸受装置は、高速回転、高回転精度および低騒音等の特長を有する。このため、流体動圧軸受装置は、ＨＤＤ等のディスク駆動装置に組み込まれるスピンドルモータ、ＰＣ等に組み込まれるファンモータ、あるいはレーザビームプリンタ（ＬＢＰ）に組み込まれるポリゴンスキャナモータなどのモータ用軸受装置として好適に使用されている。   As well known, a fluid dynamic bearing device has features such as high speed rotation, high rotation accuracy and low noise. For this reason, the fluid dynamic pressure bearing device is a motor bearing device such as a spindle motor incorporated in a disk drive such as HDD, a fan motor incorporated in PC or the like, or a polygon scanner motor incorporated in a laser beam printer (LBP). It is used suitably.

例えば特許文献１は、軸部材の外周に固定され、軸部材と共に回転側を構成する焼結金属製の軸受部材の外周面と、軸受部材を内周に収容した静止側のハウジングの内周面との間にラジアル軸受部のラジアル軸受隙間が形成される流体動圧軸受装置を開示している。この場合、ハウジングの内周に固定した軸受部材の内周面と軸部材の外周面との間にラジアル軸受隙間が形成される流体動圧軸受装置（例えば、特許文献２）に比べ、ラジアル荷重の支持能力（ラジアル軸受部の軸受剛性）を高めることができる。   For example, in Patent Document 1, the outer peripheral surface of a sintered metal bearing member fixed to the outer periphery of the shaft member and constituting the rotation side with the shaft member, and the inner peripheral surface of the stationary side housing accommodating the bearing member in the inner periphery And a fluid dynamic bearing device in which a radial bearing gap of the radial bearing portion is formed therebetween. In this case, compared to a fluid dynamic bearing device (e.g., Patent Document 2) in which a radial bearing gap is formed between the inner peripheral surface of the bearing member fixed to the inner periphery of the housing and the outer peripheral surface of the shaft member Supporting ability (bearing rigidity of the radial bearing portion) can be enhanced.

また、特許文献１の流体動圧軸受装置では、軸受部材の一端面及び他端面で、軸受部材を含む回転側をスラスト一方向及び他方向に非接触支持するスラスト軸受部のスラスト軸受隙間がそれぞれ形成されるため、ハウジングの内部空間が潤滑油で満たされる。しかしながら、この場合、流体動圧軸受装置の組み立て後に真空含浸等の煩雑な手法を用いてハウジングの内部空間を潤滑油で満たし、かつ潤滑油の油面を高精度に管理（潤滑油量を微調整）する必要がある。そのため、流体動圧軸受装置の更なる低コスト化の要請に対応することが難しい。   Further, in the fluid dynamic bearing device of Patent Document 1, the thrust bearing gap of the thrust bearing portion supporting non-contacting the rotation side including the bearing member in one thrust direction and the other direction on one end surface and the other end surface of the bearing member respectively As it is formed, the internal space of the housing is filled with lubricating oil. However, in this case, after assembling the fluid dynamic pressure bearing device, the inner space of the housing is filled with the lubricating oil using a complicated method such as vacuum impregnation, and the oil level of the lubricating oil is managed with high accuracy (the lubricating oil amount is small Needs to be adjusted. Therefore, it is difficult to meet the demand for further cost reduction of the fluid dynamic bearing device.

そこで、本出願人（本願発明者）は、軸受部材の一端面とハウジングの内底面との間に潤滑油で満たされたスラスト軸受隙間を形成すると共に、軸受部材の他端面とこれに対向配置されたシール部材との間に空気を含む軸方向隙間を形成する流体動圧軸受装置を提案している（特許文献３）。この流体動圧軸受装置では、例えばマイクロピペット等の給油具を用いてハウジングの内部空間に注油するだけでも、ハウジングの内部空間に必要量の潤滑油を介在させることができる。そのため、高精密な油面の調整・管理作業が不要となり、これを通じて軸受装置の製造コストを低廉化することが可能となる。   Therefore, the applicant (inventor) forms a thrust bearing gap filled with lubricating oil between one end surface of the bearing member and the inner bottom surface of the housing, and arranges the other end surface of the bearing member opposite to this. A fluid dynamic bearing device has been proposed in which an axial gap containing air is formed between the seal member and the seal member (Patent Document 3). In this fluid dynamic bearing device, a necessary amount of lubricating oil can be intervened in the internal space of the housing simply by lubricating the internal space of the housing using a feeder such as a micropipette, for example. Therefore, it is not necessary to perform highly precise adjustment and management of the oil surface, which makes it possible to reduce the manufacturing cost of the bearing device.

特開２００７−２４０８９号公報Japanese Patent Application Publication No. 2007-24089 特開２００３−３３６６３６号公報Japanese Patent Application Publication No. 2003-336636 特開２０１４−１７８１号公報JP, 2014-1781, A

近年、ウルトラブック（ＵＬＴＲＡＢＯＯＫ：登録商標）とも称される超薄型のノート型ＰＣが普及しつつあること等に鑑み、各種モータ用の軸受装置として使用される流体動圧軸受装置に対する一層の薄型化の要請がある。流体動圧軸受装置を薄型化するための手段として、ハウジングや軸受部材等の軸方向寸法を短縮することが考えられるが、この場合、ラジアル軸受部の軸受剛性が低下する。回転側の回転に伴って流体動圧軸受装置のラジアル軸受部に作用する荷重（ラジアル荷重）が減少するのであれば、ラジアル軸受部の軸受剛性が低下しても特段問題は生じない。しかしながら、ウルトラブック用のファンモータは、従来のファンモータと同等の冷却性能を確保すべく大型のファン（羽根）を採用する場合が多いため、流体動圧軸受装置のラジアル軸受部で支持すべき荷重は、減少するというよりもむしろ増大する傾向にある。そのため、ラジアル軸受部の軸受剛性を犠牲にする上記の対策を採ることは得策ではない。   In view of the recent spread of ultra thin notebook PCs, also referred to as ULTRABOOK (registered trademark), a further thin type for fluid dynamic bearing devices used as bearing devices for various motors. There is a request for As means for thinning the fluid dynamic bearing, it is conceivable to shorten the axial dimension of the housing, the bearing member, etc., but in this case, the bearing rigidity of the radial bearing is lowered. If the load (radial load) acting on the radial bearing portion of the fluid dynamic bearing device decreases with the rotation on the rotation side, no particular problem occurs even if the bearing rigidity of the radial bearing portion decreases. However, since the fan motor for ultra book often adopts a large fan (blade) to secure the same cooling performance as the conventional fan motor, it should be supported by the radial bearing of the fluid dynamic bearing device. The load tends to increase rather than decrease. Therefore, it is not a good idea to take the above measures that sacrifices the bearing rigidity of the radial bearing portion.

そこで、本願発明者は、特許文献３に開示された流体動圧軸受装置において、空気を含む軸方向隙間の隙間幅（軸方向寸法）を小さくすることを検討した。しかしながら、上記軸方向隙間の隙間幅を単に小さくするだけでは、ハウジングの内部空間への注油作業時、さらには流体動圧軸受装置の運転時に、油漏れが生じ易くなる。ハウジングの内部空間への注油量を少なくすれば、油漏れが生じる可能性を可及的に減じることはできるが、特にラジアル軸受隙間に十分量の潤滑油を介在させることができず、必要とされる軸受性能を安定的に発揮することが難しくなる。   Therefore, in the fluid dynamic bearing disclosed in Patent Document 3, the inventor of the present application examined reducing the width (axial dimension) of the axial gap containing air. However, simply reducing the width of the axial gap tends to cause oil leakage during the operation of lubricating the inner space of the housing and further during the operation of the fluid dynamic bearing device. Although it is possible to reduce the possibility of oil leakage as much as possible by reducing the amount of oil supplied to the internal space of the housing, it is not possible to intervene a sufficient amount of lubricating oil particularly in the radial bearing gap, and it is necessary It is difficult to exhibit the required bearing performance stably.

以上の実情に鑑み、本発明の課題は、薄型化（軸方向のコンパクト化）を実現しつつも、必要とされる軸受性能を安定的に発揮することのできる流体動圧軸受装置を提供することにある。   In view of the above situation, the object of the present invention is to provide a fluid dynamic bearing device capable of stably exhibiting the required bearing performance while realizing thinning (compact in the axial direction). It is.

上記の課題を解決するために創案された本発明は、多孔質材料で形成され、軸方向両側に端面を有する回転側の軸受部材と、軸方向一方側が閉塞された有底筒状をなし、軸受部材を内周に収容した静止側のハウジングと、軸受部材の軸方向他方側の端面と対向配置され、ハウジングの開口部をシールするためのシール隙間を形成するシール部材と、軸受部材の外周面とハウジングの内周面との間に形成されるラジアル軸受隙間と、軸受部材の軸方向一方側の端面とハウジングの内底面との間に形成されるスラスト軸受隙間とを備え、ラジアル軸受隙間及びスラスト軸受隙間が潤滑油で満たされ、ラジアル軸受隙間及びスラスト軸受隙間に形成される油膜で軸受部材がラジアル方向及びスラスト方向にそれぞれ支持されると共に、互いに対向する軸受部材の軸方向他方側の端面とシール部材の軸方向一方側の端面との間に空気を含む軸方向隙間を介在させた流体動圧軸受装置において、軸受部材の軸方向他方側の端面に潤滑油溜りを設け、潤滑油溜りの外径側の端部を、軸方向他方側の端面の範囲内で終端させ、潤滑油溜りを画成する内壁面のうち、潤滑油溜りの外径部を画成する部分を、潤滑油溜りの開口寸法を軸方向他方側に向けて漸次拡大させる方向に傾斜したテーパ面に形成したことを特徴とする。 The present invention invented to solve the above problems is formed of a porous material and has a rotary bearing member having end surfaces on both sides in the axial direction, and a bottomed cylindrical shape in which one axial side is closed, A housing on the stationary side in which the bearing member is accommodated on the inner periphery, a seal member disposed opposite to the end face on the other side in the axial direction of the bearing member to form a seal gap for sealing the opening of the housing, and the outer periphery of the bearing member A radial bearing gap formed between the surface and the inner circumferential surface of the housing, and a thrust bearing gap formed between the end face on one side in the axial direction of the bearing member and the inner bottom surface of the housing; And the thrust bearing gap is filled with lubricating oil, and the bearing members are supported in the radial direction and the thrust direction by the oil film formed in the radial bearing gap and the thrust bearing gap, respectively, and are opposed to each other. In a fluid dynamic bearing device in which an axial gap containing air is interposed between an end face on the other axial side of the bearing member and an end face on the one axial side of the seal member, the end face on the other side in the axial direction of the bearing member A lubricant oil reservoir is provided, and the outer diameter end of the lubricant oil reservoir is terminated within the range of the end surface on the other side in the axial direction, and the outer diameter portion of the lubricant oil reservoir among the inner wall surfaces defining the lubricant oil reservoir. The portion which defines the above is formed in a tapered surface which is inclined in a direction in which the opening dimension of the lubricating oil reservoir is gradually expanded toward the other side in the axial direction .

上記のように、空気を含む軸方向隙間を形成する軸受部材の軸方向他方側の端面（他端面）に潤滑油溜りを設けておけば、上記軸方向隙間の隙間幅を小さくしても、軸受部材とシール部材との間に多くの潤滑油を保持することができる。特に、潤滑油溜りの外径側の端部を、軸受部材の他端面の範囲内（軸受部材の他端外周縁部に面取りを設ける場合には、面取りよりも内径側）で終端させていることから、潤滑油溜りの形成態様がラジアル軸受隙間の隙間幅等に影響を及ぼすことはない。そのため、潤滑油溜りの深さ寸法は、加工性に悪影響を及ぼさない範囲で任意に設定する（十分に大きくする）ことができる。これにより、軸受部材とシール部材との間には、シール隙間を介しての注油作業時にも油漏れが生じる可能性を可及的に減じることができ、しかも、所定の軸受性能を安定的に発揮可能とするために必要な量の潤滑油を介在させることができる。以上より、上記軸方向隙間の隙間幅を十分に縮小することができ、これを通じて流体動圧軸受装置を軸方向にコンパクト化することができる。   As described above, if a lubricating oil reservoir is provided on the other axial end face (other end face) of the bearing member forming the axial gap containing air, the gap width of the axial gap may be reduced, A large amount of lubricating oil can be held between the bearing member and the seal member. In particular, the end on the outer diameter side of the lubricating oil reservoir is terminated within the range of the other end face of the bearing member (in the case where the outer peripheral edge of the other end of the bearing member is chamfered, the inner diameter side than the chamfer) Therefore, the formation mode of the lubricating oil reservoir does not affect the gap width and the like of the radial bearing gap. Therefore, the depth dimension of the lubricating oil reservoir can be arbitrarily set (increased sufficiently) within a range that does not adversely affect the processability. As a result, the possibility of oil leakage can be reduced as much as possible even during an oiling operation between the bearing member and the seal member through the seal gap, and a predetermined bearing performance can be stabilized. A necessary amount of lubricating oil can be intervened to make it possible. As described above, the gap width of the axial gap can be sufficiently reduced, and the fluid dynamic bearing can be made compact in the axial direction through this.

また、軸受部材の他端面に潤滑油溜りを設けておけば、回転側を構成する軸受部材が回転するのに伴って、潤滑油溜りで保持した潤滑油を外径側に飛散させ、ラジアル軸受隙間に供給することができる。これにより、ラジアル軸受隙間における油膜切れを防止してラジアル軸受部の軸受性能を高いレベルで維持することができる。以上のことから、本発明によれば、軸方向のコンパクト化を実現しつつも、必要とされる軸受性能を安定的に発揮することのできる流体動圧軸受装置を提供することができる。   Also, if a lubricating oil reservoir is provided on the other end surface of the bearing member, the lubricating oil held by the lubricating oil reservoir is scattered to the outer diameter side as the bearing member constituting the rotation side rotates, and the radial bearing It can be supplied to the gap. As a result, oil film breakage in the radial bearing gap can be prevented, and the bearing performance of the radial bearing portion can be maintained at a high level. From the above, according to the present invention, it is possible to provide a fluid dynamic bearing device capable of stably exhibiting the required bearing performance while realizing compactness in the axial direction.

潤滑油溜りを画成する内壁面のうち、潤滑油溜りの外径部を画成する部分は、潤滑油溜りの開口寸法を軸方向他方側に向けて漸次拡大させる方向に傾斜したテーパ面に形成するのが好ましい。潤滑油溜りで保持した潤滑油を、軸受部材が回転するのに伴って外径側に飛散させ易くなり、回転側の回転時におけるラジアル軸受隙間への潤滑油供給能力が向上するからである。   Of the inner wall surface defining the lubricating oil reservoir, the portion defining the outer diameter portion of the lubricating oil reservoir is a tapered surface inclined in a direction to gradually expand the opening dimension of the lubricating oil reservoir toward the other axial side. It is preferable to form. This is because the lubricating oil held by the lubricating oil reservoir is easily scattered to the outer diameter side as the bearing member rotates, and the lubricating oil supply capability to the radial bearing gap at the time of rotation on the rotational side is improved.

上記態様で潤滑油溜りを設けることにより奏される作用効果を考慮すると、潤滑油溜りは環状溝で構成するのが好ましい。この環状溝は、一本のみ設けても良いし、径方向に相互に離間して複数本設けても良い。   In consideration of the effects exerted by providing the lubricating oil reservoir in the above embodiment, the lubricating oil reservoir is preferably configured by an annular groove. Only one annular groove may be provided, or a plurality of annular grooves may be provided mutually separated in the radial direction.

上記構成において、軸受部材に、軸受部材を軸方向一方側に押し付ける外力を作用させれば、軸受部材をスラスト両方向に支持することが可能となる。そのため、スラスト軸受隙間に形成される油膜によるスラスト一方向の荷重支持能力が過大となり、これに伴って、スラスト方向の支持精度が不安定化するような事態を可及的に回避することができる。   In the above configuration, if an external force that presses the bearing member in one axial direction is applied to the bearing member, the bearing member can be supported in both thrust directions. Therefore, the load supporting ability in one thrust direction due to the oil film formed in the thrust bearing gap becomes excessive, and the situation that the support precision in the thrust direction becomes unstable can be avoided as much as possible. .

上記外力は、例えば磁力で与えることができる。この磁力は、例えば、モータの静止側に設けられるステータコイルと、モータの回転側に設けられるロータマグネットとを軸方向にずらして配置することによって与えることができる。この種の流体動圧軸受装置が組み込まれる各種モータは、通常、ロータマグネットとステータコイルとを必須の構成部材として備える。従って、上記外力を特段のコスト増を招くことなく安価に付与することができる。   The external force can be applied, for example, by magnetic force. The magnetic force can be provided, for example, by axially displacing a stator coil provided on the stationary side of the motor and a rotor magnet provided on the rotational side of the motor. Generally, various motors in which this type of fluid dynamic bearing device is incorporated include a rotor magnet and a stator coil as essential components. Therefore, the above external force can be applied inexpensively without causing a special increase in cost.

以上の構成において、軸受部材を外周に固定した軸部材の外周面と、ハウジングと一体又は別体に設けたシール部材の内周面との間に、ハウジングの開口部をシールするシール隙間を形成することができる。このようにすれば、潤滑油溜りに保持された潤滑油が軸受部材の回転に伴って外径側に飛散した際に、この飛散した潤滑油がシール隙間を介して装置外部に漏れ出すような事態を効果的に防止することができる。   In the above configuration, a seal gap for sealing the opening of the housing is formed between the outer peripheral surface of the shaft member having the bearing member fixed to the outer periphery and the inner peripheral surface of the seal member integrally or separately provided with the housing. can do. In this way, when the lubricating oil held in the lubricating oil reservoir scatters to the outer diameter side as the bearing member rotates, the scattered lubricating oil leaks to the outside of the apparatus through the seal gap. The situation can be effectively prevented.

以上の構成において、ラジアル軸受隙間を介して対向するハウジングの内周面と軸受部材の外周面の何れか一方又は双方には、ラジアル軸受隙間内の潤滑油に動圧作用を発生させる動圧発生部（ラジアル動圧発生部）を設けることができる。   In the above configuration, dynamic pressure is generated to generate dynamic pressure in lubricating oil in the radial bearing gap on either or both of the inner circumferential surface of the housing and the outer circumferential surface of the bearing member facing each other through the radial bearing gap. A part (radial dynamic pressure generating part) can be provided.

ラジアル動圧発生部は、軸受部材の回転時にラジアル軸受隙間内の潤滑油をスラスト軸受隙間側に押し込む形状とするのが好ましい。スラスト軸受隙間における油膜切れを可及的に防止し、スラスト一方向の回転精度の安定化を図ることができるからである。   It is preferable that the radial dynamic pressure generating portion be shaped such that the lubricating oil in the radial bearing gap is pushed to the thrust bearing gap side when the bearing member rotates. This is because oil film breakage in the thrust bearing gap can be prevented as much as possible, and the rotation accuracy in one thrust direction can be stabilized.

回転側には、軸受部材の両端面を連通させる連通路を設けることができる。このような連通路を設けておくことにより、軸受装置の運転中に、ハウジングの内部空間に介在する潤滑油を積極的に流動循環させること可能となるので、軸受装置内部の圧力バランスの崩れや、各軸受隙間における潤滑油不足に起因した軸受性能の低下を効果的に防止することができる。   The rotation side can be provided with a communication passage that causes both end surfaces of the bearing member to communicate with each other. By providing such a communication passage, it is possible to actively flow and circulate the lubricating oil present in the internal space of the housing during operation of the bearing device, so that the pressure balance inside the bearing device may be lost. It is possible to effectively prevent the deterioration of the bearing performance caused by the shortage of lubricating oil in each bearing gap.

以上で示した本発明に係る流体動圧軸受装置は、以上で示した種々の特徴を有することから、例えばＰＣ用のファンモータや、ディスク駆動装置用のスピンドルモータ等の各種モータに組み込んで好適に使用することができ、しかも各種モータの低コスト化に寄与することができる。   Since the fluid dynamic bearing device according to the present invention described above has the various features described above, it can be suitably incorporated into various motors such as a fan motor for a PC or a spindle motor for a disk drive. And can contribute to the cost reduction of various motors.

以上より、本発明によれば、一層の薄型化（軸方向寸法の短縮）を実現しつつも、必要とされる軸受性能を安定的に発揮することのできる流体動圧軸受装置を低コストに提供することができる。   As described above, according to the present invention, it is possible to reduce the cost of the fluid dynamic bearing device capable of stably exhibiting the required bearing performance while realizing further thinning (shortening of the axial dimension). Can be provided.

ファンモータの一構成例を概念的に示す断面図である。FIG. 2 is a cross-sectional view conceptually showing one configuration example of a fan motor. 本発明の第１実施形態に係る流体動圧軸受装置を示す断面図である。FIG. 1 is a cross-sectional view showing a fluid dynamic bearing according to a first embodiment of the present invention. 図２に示す軸受部材の下端面を示す平面図である。It is a top view which shows the lower end surface of the bearing member shown in FIG. 図２に示す軸受部材の上端面を示す平面図である。It is a top view which shows the upper end surface of the bearing member shown in FIG. （ａ）図は図４に示した潤滑油溜りの断面図、（ｂ）図は潤滑油溜りの変形例を示す断面図である。(A) A figure is sectional drawing of a lubricating oil reservoir shown in FIG. 4, (b) A figure is a sectional view showing a modification of a lubricating oil reservoir. 変形例に係る軸受部材の上端面を示す平面図である。It is a top view which shows the upper end surface of the bearing member which concerns on a modification. 本発明の第２実施形態に係る流体動圧軸受装置を示す断面図である。It is a sectional view showing a fluid dynamic pressure bearing device concerning a 2nd embodiment of the present invention. 本発明の第３実施形態に係る流体動圧軸受装置を示す断面図である。It is sectional drawing which shows the fluid hydrodynamic bearing apparatus which concerns on 3rd Embodiment of this invention.

以下、本発明の実施の形態を図面に基づいて説明する。   Hereinafter, embodiments of the present invention will be described based on the drawings.

図１に、本発明の一実施形態に係る流体動圧軸受装置１が組み込まれたファンモータの構成例を概念的に示す。同図に示すファンモータは、流体動圧軸受装置１と、モータの静止側を構成するモータベース６と、モータベース６に固定されたステータコイル５と、モータの回転側を構成し、ファン（羽根）を有するロータ３と、ロータ３に固定され、ステータコイル５と半径方向のギャップを介して対向するロータマグネット４とを備える。流体動圧軸受装置１のハウジング７は、モータベース６の内周に固定され、ロータ３は、流体動圧軸受装置１の軸部材２１の一端に固定されている。このように構成されたファンモータにおいて、ステータコイル５に通電すると、ステータコイル５とロータマグネット４との間の電磁力でロータマグネット４が回転し、これに伴って軸部材２１、軸部材２１に固定された羽根を有するロータ３及びロータ３に固定されたロータマグネット４等を備えた回転体２が回転する。   FIG. 1 conceptually shows a configuration example of a fan motor in which a fluid dynamic bearing device 1 according to an embodiment of the present invention is incorporated. The fan motor shown in the figure includes a fluid dynamic pressure bearing device 1, a motor base 6 constituting the stationary side of the motor, a stator coil 5 fixed to the motor base 6, and a rotation side of the motor. And a rotor magnet 4 fixed to the rotor 3 and facing the stator coil 5 via a radial gap. The housing 7 of the fluid dynamic bearing 1 is fixed to the inner periphery of the motor base 6, and the rotor 3 is fixed to one end of the shaft member 21 of the fluid dynamic bearing 1. In the fan motor configured as described above, when the stator coil 5 is energized, the rotor magnet 4 is rotated by the electromagnetic force between the stator coil 5 and the rotor magnet 4, and accordingly, the shaft member 21 and the shaft member 21 A rotor 3 having a fixed blade and a rotor magnet 4 fixed to the rotor 3 rotates.

なお、回転体２が回転すると、ロータ３に設けられた羽根の形態に応じて図中上向き又は下向きに風が送られる。このため、回転体２の回転中にはこの送風作用の反力として、回転体２に図中下向き又は上向きの推力が作用する。ステータコイル５とロータマグネット４との間には、この推力を打ち消す方向の磁力（斥力）を作用させており、上記推力と磁力の大きさの差により生じたスラスト荷重が流体動圧軸受装置１のスラスト軸受部Ｔで支持される。上記推力を打ち消す方向の磁力は、例えば、ステータコイル５とロータマグネット４とを軸方向にずらして配置することにより発生させることができる（詳細な図示は省略）。また、回転体２の回転時には、流体動圧軸受装置１の軸部材２１及び軸受部材２２にラジアル荷重が作用する。このラジアル荷重は、流体動圧軸受装置１のラジアル軸受部Ｒで支持される。   When the rotating body 2 rotates, wind is sent upward or downward in the drawing depending on the form of the blades provided on the rotor 3. For this reason, during rotation of the rotating body 2, a downward or upward thrust in the drawing acts on the rotating body 2 as a reaction force of the blowing action. Between the stator coil 5 and the rotor magnet 4, a magnetic force (repulsive force) in the direction to cancel this thrust acts, and the thrust load generated by the difference between the thrust and the magnetic force is the fluid dynamic bearing device 1 Supported by the thrust bearing portion T of FIG. The magnetic force in the direction to cancel the thrust can be generated, for example, by displacing the stator coil 5 and the rotor magnet 4 in the axial direction (detailed illustration is omitted). Further, when the rotating body 2 rotates, a radial load acts on the shaft member 21 and the bearing member 22 of the fluid dynamic pressure bearing device 1. The radial load is supported by the radial bearing portion R of the fluid dynamic bearing device 1.

図２に、本発明の第１実施形態に係る流体動圧軸受装置１を示す。この流体動圧軸受装置１は、回転側（回転体２）を構成する軸部材２１及びその外周に固定された軸受部材２２と、軸受部材２２及び軸部材２１を内周に収容した静止側のハウジング７と、シール部材９とを主要な構成部材として備えている。ハウジング７の内部空間には潤滑油１１（密な散点ハッチングで示す）が充填されており、図２に示す状態では、少なくともラジアル軸受部Ｒのラジアル軸受隙間及びスラスト軸受部Ｔのスラスト軸受隙間が潤滑油１１で満たされている。なお、以下では、説明の便宜上、シール部材９が配置された側を上側、その軸方向反対側を下側とするが、流体動圧軸受装置１の使用態様を限定するものではない。   FIG. 2 shows a fluid dynamic bearing 1 according to a first embodiment of the present invention. The fluid dynamic pressure bearing device 1 has a shaft member 21 constituting the rotation side (rotary body 2) and a bearing member 22 fixed to the outer periphery thereof, and a stationary side in which the bearing member 22 and the shaft member 21 are accommodated in the inner periphery. A housing 7 and a seal member 9 are provided as main components. The inner space of the housing 7 is filled with the lubricating oil 11 (shown by dense scattered dots), and in the state shown in FIG. 2, at least the radial bearing gap of the radial bearing portion R and the thrust bearing gap of the thrust bearing portion T Is filled with lubricating oil 11. In the following, for convenience of explanation, the side on which the seal member 9 is disposed is referred to as the upper side, and the opposite side in the axial direction is referred to as the lower side, but the use mode of the fluid dynamic bearing 1 is not limited.

ハウジング７は、円筒状の筒部７ａと、筒部７ａの下端開口を閉塞する底部７ｂとを有する有底筒状をなし、ここでは筒部７ａと底部７ｂが金属又は樹脂で一体に形成されている。筒部７ａの内周面は、段部を介して大径内周面７ａ１と小径内周面７ａ２とに区画され、大径内周面７ａ１にはシール部材９が固定される。小径内周面７ａ２は、軸部材２１に固定された軸受部材２２の外周面２２ａとの間にラジアル軸受隙間を形成する円筒状領域を有し、該円筒状領域は凹凸のない平滑面に形成されている。また、底部７ｂの内底面７ｂ１は、軸受部材２２の下端面２２ｃとの間にスラスト軸受隙間を形成する円環状領域を有し、該円環状領域は凹凸のない平滑面に形成されている。   The housing 7 has a bottomed cylindrical shape having a cylindrical cylindrical portion 7a and a bottom portion 7b closing the lower end opening of the cylindrical portion 7a. Here, the cylindrical portion 7a and the bottom portion 7b are integrally formed of metal or resin. ing. The inner circumferential surface of the cylindrical portion 7a is divided into a large diameter inner circumferential surface 7a1 and a small diameter inner circumferential surface 7a2 through the step portion, and the seal member 9 is fixed to the large diameter inner circumferential surface 7a1. The small-diameter inner peripheral surface 7a2 has a cylindrical region forming a radial bearing gap with the outer peripheral surface 22a of the bearing member 22 fixed to the shaft member 21, and the cylindrical region is formed as a smooth surface without unevenness. It is done. Further, the inner bottom surface 7b1 of the bottom portion 7b has an annular region forming a thrust bearing gap with the lower end surface 22c of the bearing member 22, and the annular region is formed as a smooth surface without unevenness.

シール部材９は金属又は樹脂で円環状に形成され、ハウジング７の大径内周面７ａ１に適宜の手段で固定される。シール部材９の内周面９ａと、これに対向する軸部材２１の外周面２１ａとの間にはハウジング７の開口部をシールするシール隙間（ラビリンスシール）Ｓが形成され、軸受部材２２の上側は、シール隙間Ｓを介して大気に開放されている。図示は省略するが、シール隙間Ｓを介しての潤滑油漏れを効果的に防止するため、シール隙間Ｓに隣接して大気に接した軸部材２１の外周面２１ａやシール部材９の上端面に撥油膜を形成しても良い。   The seal member 9 is formed in an annular shape of metal or resin, and is fixed to the large diameter inner peripheral surface 7a1 of the housing 7 by an appropriate means. A seal gap (labyrinth seal) S for sealing the opening of the housing 7 is formed between the inner peripheral surface 9 a of the seal member 9 and the outer peripheral surface 21 a of the shaft member 21 opposed thereto. Is open to the atmosphere via the seal gap S. Although illustration is omitted, in order to effectively prevent lubricating oil leakage through the seal gap S, the outer peripheral surface 21a of the shaft member 21 adjacent to the seal gap S in contact with the atmosphere or the upper end surface of the seal member 9 An oil repellent film may be formed.

軸部材２１は、ステンレス鋼等の金属材料で形成され、その外周面２１ａは平滑な円筒面に形成されている。軸部材２１の上端部に、羽根を有するロータ３が固定されている。   The shaft member 21 is formed of a metal material such as stainless steel, and the outer peripheral surface 21 a is formed as a smooth cylindrical surface. A rotor 3 having blades is fixed to an upper end portion of the shaft member 21.

軸受部材２２は、多孔質体、ここでは銅（銅系合金を含む）あるいは鉄（鉄系合金を含む）の金属粉末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る。軸受部材２２は、焼結金属以外の多孔質体、例えば多孔質樹脂で形成することも可能である。この軸受部材２２は、その下端面２２ｃが軸部材２１の下端面２１ｂよりも軸方向外側（下側）に位置するようにして、軸部２１の外周面２１ａに適宜の手段で固定されている。   The bearing member 22 is formed in a cylindrical shape by a porous body, in this case, a porous body of a sintered metal mainly composed of a metal powder of copper (including a copper-based alloy) or iron (including an iron-based alloy). . The bearing member 22 can also be formed of a porous body other than a sintered metal, for example, a porous resin. The bearing member 22 is fixed to the outer peripheral surface 21 a of the shaft portion 21 by an appropriate means such that the lower end surface 22 c is located axially outside (lower side) of the lower end surface 21 b of the shaft member 21. .

軸受部材２２を含む回転体２は、軸受部材２２の両端面２２ｂ，２２ｃを連通させる連通路８を一又は複数備えている。ここでは、図３及び図４に示すように、軸受部材２２の内周面２２ｄに形成した軸方向溝２２ｄ１と、平滑な円筒面状をなす軸部材２１の外周面２１ａとで連通路８を形成している。もちろん、軸部材２１の外周面２１ａに軸方向溝を設けることで連通路８を形成することもできる。   The rotating body 2 including the bearing member 22 is provided with one or more communicating passages 8 which allow the both end surfaces 22 b and 22 c of the bearing member 22 to communicate with each other. Here, as shown in FIGS. 3 and 4, the communication passage 8 is formed by the axial groove 22d1 formed in the inner peripheral surface 22d of the bearing member 22 and the outer peripheral surface 21a of the shaft member 21 having a smooth cylindrical surface. It is formed. Of course, the communication passage 8 can also be formed by providing an axial groove on the outer peripheral surface 21 a of the shaft member 21.

軸受部材２２の外周面２２ａには、対向するハウジング７の小径内周面７ａ２との間にラジアル軸受部Ｒのラジアル軸受隙間を形成する円筒状のラジアル軸受面が設けられる。ラジアル軸受面には、ラジアル軸受隙間内の潤滑油１１に動圧作用を発生させるための動圧発生部（ラジアル動圧発生部）Ａが形成されている。図示例のラジアル動圧発生部Ａは、互いに反対方向に傾斜し、かつ軸方向に離間した複数の動圧溝Ａａ１，Ａｂ１をヘリングボーン形状に配列して構成されている。上側の動圧溝Ａａ１の軸方向寸法は、下側の動圧溝Ａｂ１の軸方向寸法よりも大きくなっている。これにより、回転体２の回転時、ラジアル軸受隙間内の潤滑油１１は、下向き（スラスト軸受部Ｔのスラスト軸受隙間側）に押し込まれる。   The outer peripheral surface 22a of the bearing member 22 is provided with a cylindrical radial bearing surface which forms a radial bearing gap of the radial bearing portion R with the small diameter inner peripheral surface 7a2 of the opposing housing 7. A dynamic pressure generating portion (radial dynamic pressure generating portion) A for generating a dynamic pressure action on the lubricating oil 11 in the radial bearing gap is formed on the radial bearing surface. The radial dynamic pressure generating portion A in the illustrated example is configured by arranging a plurality of dynamic pressure grooves Aa1 and Ab1 which are inclined in mutually opposite directions and are axially separated from each other in a herringbone shape. The axial dimension of the upper dynamic pressure groove Aa1 is larger than the axial dimension of the lower dynamic pressure groove Ab1. Thereby, when the rotating body 2 rotates, the lubricating oil 11 in the radial bearing gap is pushed downward (the thrust bearing gap side of the thrust bearing portion T).

ラジアル動圧発生部Ａを構成する各動圧溝は、最終的に軸受部材２２となる金属粉末の圧粉体を成形するのと同時に型成形することもできるし、圧粉体を焼結してなる円筒状の焼結体にサイジング（寸法矯正）を施すのと同時に型成形することもできる。また、焼結金属の良好な加工性に鑑み、外周面が平滑面に形成された焼結体に転造加工等を施すことで形成することもできる。また、ラジアル動圧発生部Ａは、例えば、スパイラル形状の動圧溝を円周方向に複数配列して構成することもできる。   The respective dynamic pressure grooves constituting the radial dynamic pressure generating portion A can be molded at the same time as molding of the green powder of the metal powder which finally becomes the bearing member 22 or sintering of the green powder It is also possible to mold at the same time as sizing (dimensional correction) is applied to the cylindrical sintered body. Moreover, in view of the favorable workability of a sintered metal, it can also form by giving rolling processing etc. to the sintered compact in which the outer peripheral surface was formed in the smooth surface. The radial dynamic pressure generating portion A can also be configured, for example, by arranging a plurality of spiral dynamic pressure grooves in the circumferential direction.

図３に示すように、軸受部材２２の下端面２２ｃには、対向するハウジング７の内底面７ｂ１との間にスラスト軸受部Ｔのスラスト軸受隙間を形成する環状のスラスト軸受面が設けられる。このスラスト軸受面には、回転体２が回転するのに伴って、スラスト軸受隙間内の潤滑油１１に動圧作用を発生させるためのスラスト動圧発生部Ｂが形成されている。スラスト動圧発生部Ｂは、スパイラル形状の動圧溝Ｂａを周方向に所定間隔で複数設けて構成されており、回転体２の回転時、スラスト軸受隙間内の潤滑油１１を内径側に押し込むポンプイン機能を有する。スラスト動圧発生部Ｂは、ヘリングボーン形状の動圧溝を周方向に所定間隔で配置して構成することもできる。   As shown in FIG. 3, the lower end surface 22c of the bearing member 22 is provided with an annular thrust bearing surface which forms a thrust bearing gap of the thrust bearing portion T with the inner bottom surface 7b1 of the opposing housing 7. On the thrust bearing surface, there is formed a thrust dynamic pressure generating portion B for generating dynamic pressure action on the lubricating oil 11 in the thrust bearing gap as the rotating body 2 rotates. The thrust dynamic pressure generating portion B is configured by providing a plurality of spiral-shaped dynamic pressure grooves Ba at predetermined intervals in the circumferential direction, and pushes the lubricating oil 11 in the thrust bearing gap to the inner diameter side when the rotating body 2 rotates. It has a pump-in function. The thrust dynamic pressure generating portion B can also be configured by arranging herringbone-shaped dynamic pressure grooves at predetermined intervals in the circumferential direction.

軸受部材２２の上端面２２ｂと、これに対向するシール部材９の下端面９ｂとの間には空気を含む軸方向隙間（環状空間）１０が設けられる。流体動圧軸受装置１が図２に示す姿勢で配置された状態（シール隙間Ｓを鉛直方向上側に配置した状態）では、少なくともラジアル軸受部Ｒのラジアル軸受隙間及びスラスト軸受部Ｔのスラスト軸受隙間が潤滑油１１で満たされ、ハウジング７の内部空間に充填した潤滑油１１の油面が軸方向隙間１０の範囲内に保持される。従って、ハウジング７の内部空間に充填される潤滑油１１の量（体積）は、ハウジング７の内部空間の容積よりも少なくなっている。   An axial gap (annular space) 10 containing air is provided between the upper end surface 22 b of the bearing member 22 and the lower end surface 9 b of the seal member 9 opposed thereto. In a state where the fluid dynamic bearing device 1 is disposed in the attitude shown in FIG. 2 (a state where the seal gap S is disposed on the upper side in the vertical direction), at least the radial bearing gap of the radial bearing portion R and the thrust bearing gap of the thrust bearing portion T Is filled with the lubricating oil 11, and the oil level of the lubricating oil 11 filled in the internal space of the housing 7 is held within the range of the axial gap 10. Therefore, the amount (volume) of the lubricating oil 11 filled in the internal space of the housing 7 is smaller than the volume of the internal space of the housing 7.

軸受部材２２の上端面２２ｂには、潤滑油１１を保持した潤滑油溜り１２が設けられ、本実施形態では、周方向で無端の環状溝１３で潤滑油溜り１２が構成される。潤滑油溜り１２の外径端部１２ａおよび内径端部は、軸受部材２２の上端面２２ｂの範囲内でそれぞれ終端している。つまり、軸受部材２２の上端外周縁部および内周縁部のそれぞれに面取り部２２ｅ，２２ｆが設けられている本実施形態において、潤滑油溜り１２の外径端部１２ａは面取り部２２ｅよりも内径側に位置すると共に、潤滑油溜り１２の内径端部は面取り部２２ｆよりも外径側に位置している。環状溝１３は、その溝幅（開口寸法）を軸方向全域で一定とした矩形状の断面形状に形成しても良いが、本実施形態の環状溝１３は、その溝幅を上側に向けて漸次拡大させる方向の断面形状を有する。具体的には、図５（ａ）に拡大して示すように、環状溝１３の外径部を構成し、環状溝１３の溝幅を上側に向けて漸次拡大させる方向に傾斜したテーパ面（テーパ状内壁面）１３ａと、環状溝１３の内径部を構成する軸方向と平行な円筒面（円筒状内壁面）１３ｂと、環状溝１３の溝底を構成する平端面１３ｃとで画成された、断面台形状の形態を有する。   A lubricating oil reservoir 12 holding the lubricating oil 11 is provided on the upper end surface 22b of the bearing member 22. In the present embodiment, the lubricating oil reservoir 12 is configured by an endless annular groove 13 in the circumferential direction. The outer diameter end 12 a and the inner diameter end of the lubricating oil reservoir 12 respectively terminate within the range of the upper end surface 22 b of the bearing member 22. That is, in the present embodiment in which the chamfered portions 22e and 22f are provided on the upper outer peripheral edge portion and the inner peripheral edge portion of the bearing member 22, the outer diameter end 12a of the lubricating oil reservoir 12 is on the inner diameter side than the chamfered portion 22e. The inner diameter end of the lubricating oil reservoir 12 is located on the outer diameter side of the chamfered portion 22f. The annular groove 13 may be formed in a rectangular cross-sectional shape in which the groove width (opening dimension) is constant throughout the axial direction. However, with the annular groove 13 of this embodiment, the groove width is directed upward. It has a cross-sectional shape in a direction to be gradually enlarged. Specifically, as shown enlarged in FIG. 5 (a), a tapered surface which constitutes the outer diameter portion of the annular groove 13 and is inclined in a direction in which the groove width of the annular groove 13 is gradually expanded upward A tapered inner wall surface 13a, a cylindrical surface (cylindrical inner wall surface) 13b parallel to the axial direction that constitutes the inner diameter portion of the annular groove 13, and a flat end surface 13c that constitutes the groove bottom of the annular groove 13 In addition, it has a trapezoidal cross-sectional form.

潤滑油溜り１２としての環状溝１３の溝深さは、面取り部２２ｅ，２２ｆの面取り量よりも大きく設定される。例えば、面取り部２２ｅ，２２ｆの面取り量を０．１５ｍｍとした場合、環状溝１３の溝深さは０．２ｍｍに設定することができる。また、軸受部材２２として、内径φ１．５ｍｍ×外径φ５ｍｍのものを使用する場合、潤滑油溜り１２としての環状溝１３は、例えば、内径φ２．７５ｍｍ×外径φ３．５５ｍｍに形成することができる。   The groove depth of the annular groove 13 as the lubricating oil reservoir 12 is set larger than the amount of chamfering of the chamfered portions 22e and 22f. For example, when the amount of chamfering of the chamfers 22e and 22f is 0.15 mm, the groove depth of the annular groove 13 can be set to 0.2 mm. When the bearing member 22 having an inner diameter of 1.5 mm and an outer diameter of 5 mm is used, the annular groove 13 as the lubricating oil reservoir 12 may be formed to have an inner diameter of 2.75 mm and an outer diameter of 3.55 mm, for example. it can.

なお、環状溝１３の断面形状は上記のものに限られるわけではなく、例えば図５（ｂ）に示すように、環状溝１３の溝幅を上側に向けて漸次拡大させる方向に傾斜し、環状溝１３の外径部を構成するテーパ面（テーパ状内壁面）１３ａと、環状溝１３の内径部を構成する軸方向と平行な円筒面（円筒状内壁面）１３ｂとで画成されるような断面三角形状としても良い。また、図示は省略するが、互いに反対方向に傾斜した２つのテーパ状内壁面で画成されるような断面三角形状としても良い。さらに、環状溝１３は、一本のみならず、図６に示すように、径方向に相互に離間して複数本（図示例は２本）設けても良い。   The cross-sectional shape of the annular groove 13 is not limited to the above. For example, as shown in FIG. 5 (b), the annular groove 13 is inclined in the direction of gradually expanding the groove width upward, A tapered surface (taper shaped inner wall surface) 13a constituting the outer diameter portion of the groove 13 and a cylindrical surface (cylindrical inner wall surface) 13b parallel to the axial direction constituting the inner diameter portion of the annular groove 13 The cross section may be triangular. Although not shown, it may be triangular in cross section as defined by two tapered inner wall surfaces inclined in opposite directions. Furthermore, not only one annular groove 13 but, as shown in FIG. 6, a plurality of (two in the illustrated example) may be provided mutually separated in the radial direction.

軸受部材２２の下端面２２ｃ及び上端面２２ｂのそれぞれに設けられる動圧溝Ｂａ及び潤滑油溜り１２（環状溝１３）は、ラジアル動圧発生部Ａを構成する動圧溝と同様に、最終的に軸受部材２２となる金属粉末の圧粉体を成形するのと同時に型成形することもできるし、圧粉体を焼結してなる焼結体にサイジング（寸法矯正）を施すのと同時に型成形することもできる。また、焼結金属の良好な加工性に鑑み、両端面が平滑面に成形された焼結体にプレス等の塑性加工を施すことで形成することもできる。   The dynamic pressure grooves Ba and the lubricating oil reservoir 12 (annular groove 13) provided on the lower end surface 22c and the upper end surface 22b of the bearing member 22 respectively are the same as the dynamic pressure grooves constituting the radial dynamic pressure generating portion A. Can be molded at the same time as molding the green powder of the metal powder to be the bearing member 22 or at the same time as sizing is applied to the sintered body formed by sintering the green compact. It can also be molded. Moreover, in view of the favorable workability of a sintered metal, it can also form by giving plastic working, such as a press, to the sintered compact in which both end surfaces were shape | molded by the smooth surface.

以上の構成を具備する流体動圧軸受装置１は、例えば、軸部材２１及びその外周に固定した軸受部材２２をハウジング７の内周に挿入し、ハウジング７の大径内周面７ａ１にシール部材９を固定した後、マイクロピペット等の給油具を用いてシール隙間Ｓを介してハウジング７の内部空間に潤滑油１１を充填（注油）することにより完成する。   The fluid dynamic bearing device 1 having the above configuration, for example, inserts the shaft member 21 and the bearing member 22 fixed to the outer periphery thereof into the inner periphery of the housing 7 and seals the large diameter inner peripheral surface 7a1 of the housing 7 After fixing 9, the inner space of the housing 7 is filled (lubricated) with the lubricating oil 11 through the seal gap S using a feeder such as a micropipette.

以上の構成からなる流体動圧軸受装置１において、軸部材２１及び軸受部材２２を含む回転体２が回転すると、軸受部材２２の外周面２２ａに設けたラジアル軸受面と、これに対向するハウジング７の小径内周面７ａ２との間にラジアル軸受隙間が形成される。そして回転体２の回転に伴い、ラジアル軸受隙間に形成される油膜圧力がラジアル動圧発生部Ａの動圧作用によって高められ、回転体２をラジアル方向に非接触支持するラジアル軸受部Ｒが形成される。これと同時に、軸受部材２２の下端面２２ｃに設けられたスラスト軸受面とこれに対向するハウジング７の内底面７ｂ１との間にスラスト軸受隙間が形成される。そして、回転体２の回転に伴い、スラスト軸受隙間の油膜圧力がスラスト動圧発生部Ｂの動圧作用によって高められ、回転体２をスラスト一方向に非接触支持（上方に浮上支持）するスラスト軸受部Ｔが形成される。なお、図１を参照しながら説明したように、回転体２には、これを下側に押し付けるための外力（磁力）を作用させており、これにより、回転体２の過浮上が抑止される。   In the fluid dynamic bearing device 1 configured as described above, when the rotating body 2 including the shaft member 21 and the bearing member 22 rotates, the radial bearing surface provided on the outer peripheral surface 22 a of the bearing member 22 and the housing 7 opposed thereto A radial bearing gap is formed between the small diameter inner peripheral surface 7a2 of Then, with the rotation of the rotating body 2, the oil film pressure formed in the radial bearing gap is increased by the dynamic pressure action of the radial dynamic pressure generating portion A, and the radial bearing portion R supporting the rotating body 2 in the non-contact manner in the radial direction is formed. Be done. At the same time, a thrust bearing gap is formed between the thrust bearing surface provided on the lower end surface 22c of the bearing member 22 and the inner bottom surface 7b1 of the housing 7 opposed thereto. Then, with the rotation of the rotating body 2, the oil film pressure in the thrust bearing gap is increased by the dynamic pressure action of the thrust dynamic pressure generating portion B, and the thrust for supporting the rotating body 2 in a non-contact manner (floating support upward) in one thrust direction. The bearing portion T is formed. As described with reference to FIG. 1, an external force (magnetic force) is applied to the rotating body 2 to press the rotating body 2 downward, thereby suppressing the excessive floating of the rotating body 2 .

上述したように、回転体２の回転時には、ラジアル軸受隙間内の潤滑油１１が下方に押し込まれる。これにより、回転体２の回転時には、軸受部材２２の外周面２２ａとハウジング７の内周面７ａ２との間の隙間（ラジアル軸受隙間）に介在する潤滑油１１は下方に流動し、スラスト軸受部Ｔのスラスト軸受隙間→連通路８→軸受部材２２の上端面２２ｂとシール部材９の下端面９ｂとの間の軸方向隙間１０という経路を循環して、ラジアル軸受部Ｒのラジアル軸受隙間に再び引き込まれる。特に、本実施形態では、スラスト動圧発生部Ｂがスラスト軸受隙間内の潤滑油１１を内径側に押し込むポンプイン機能を有することから、潤滑油１１の流動循環が促進される。このような構成とすることで、ハウジング７の内部空間の圧力バランスが保たれると同時に、ラジアル軸受部Ｒのラジアル軸受隙間及びスラスト軸受部Ｔのスラスト軸受隙間における油膜切れを防止することができるので、軸受性能の安定化を図ることができる。   As described above, when the rotating body 2 rotates, the lubricating oil 11 in the radial bearing gap is pushed downward. Thereby, when the rotating body 2 rotates, the lubricating oil 11 interposed in the gap (radial bearing gap) between the outer peripheral surface 22a of the bearing member 22 and the inner peripheral surface 7a2 of the housing 7 flows downward, and the thrust bearing portion The axial bearing clearance T of T → the communication passage 8 → the axial clearance 10 between the upper end surface 22b of the bearing member 22 and the lower end surface 9b of the seal member 9 circulates in the radial bearing clearance of the radial bearing portion R Be drawn. In particular, in the present embodiment, since the thrust dynamic pressure generating portion B has a pump-in function of pushing the lubricating oil 11 in the thrust bearing gap to the inner diameter side, the fluid circulation of the lubricating oil 11 is promoted. With such a configuration, pressure balance in the internal space of the housing 7 can be maintained, and oil film breakage in the radial bearing gap of the radial bearing portion R and the thrust bearing gap of the thrust bearing portion T can be prevented. Therefore, the bearing performance can be stabilized.

以上に示すように、本発明に係る流体動圧軸受装置１では、シール部材９の下端面９ｂとの間に空気を含む軸方向隙間１０を形成する軸受部材２２の上端面２２ｂに潤滑油溜り１２としての環状溝１３を設けている。このようにすれば、軸方向隙間１０の隙間幅を小さくしても、軸受部材２２とシール部材９との間の軸方向隙間１０に多くの潤滑油１１を保持することができる。特に、潤滑油溜り１２の外径端部１２ａを、軸受部材２２の上端面２２ｂの範囲内で終端させていることから、潤滑油溜り１２の形成態様がラジアル軸受隙間の隙間幅等に影響を及ぼすことはない。そのため、潤滑油溜り１２の深さ寸法は、加工性に悪影響を及ぼさない範囲で任意に設定する（十分に大きくする）ことができる。これにより、軸受部材２２とシール部材９との間には、シール隙間Ｓを介しての注油作業時にも油漏れが生じる可能性を可及的に減じることができ、しかも、ラジアル軸受部Ｒおよびスラスト軸受部Ｔの軸受性能を安定的に発揮可能とするために必要な量の潤滑油１１を介在させることができる。以上より、本発明によれば、軸方向隙間１０の隙間幅を十分に縮小することができ、これを通じて流体動圧軸受装置１を軸方向にコンパクト化することができる。   As described above, in the fluid dynamic pressure bearing device 1 according to the present invention, lubricating oil is accumulated in the upper end surface 22b of the bearing member 22 which forms the axial gap 10 containing air between the lower end surface 9b of the seal member 9 An annular groove 13 as 12 is provided. In this way, even if the gap width of the axial gap 10 is reduced, a large amount of lubricating oil 11 can be held in the axial gap 10 between the bearing member 22 and the seal member 9. In particular, since the outer diameter end 12a of the lubricating oil reservoir 12 is terminated within the range of the upper end surface 22b of the bearing member 22, the formation mode of the lubricating oil reservoir 12 affects the width of the radial bearing gap, etc. It has no effect. Therefore, the depth dimension of the lubricating oil reservoir 12 can be arbitrarily set (increased sufficiently) within a range that does not adversely affect the processability. As a result, the possibility of oil leakage between the bearing member 22 and the seal member 9 can be reduced as much as possible during the oiling operation through the seal gap S, and the radial bearing portion R and the radial bearing portion R A necessary amount of lubricating oil 11 can be interposed in order to stably exhibit the bearing performance of the thrust bearing portion T. As described above, according to the present invention, the gap width of the axial gap 10 can be sufficiently reduced, and the fluid dynamic bearing device 1 can be made compact in the axial direction through this.

なお、上記の「シール隙間Ｓを介しての注油作業時にも油漏れが生じる可能性を可及的に減じることができる」とは、「注油量の管理幅が拡大する」ことと同義である。参考までに、内径φ１．５ｍｍ×外径φ５ｍｍであって、軸方向寸法１．５ｍｍの軸受部材２２を使用する場合に、潤滑油溜り１２としての環状溝１３を設けない場合には、注油量の管理幅は最大でも０．３ｍｇしか確保できなかった。これに対し、内径φ２．７５ｍｍ×外径φ３．５５ｍｍ×深さ寸法０．２ｍｍの環状溝１３を上記寸法の軸受部材２２に形成すると、注油量の管理幅を１．０ｍｇ程度にまで拡大することができる。従って、注油作業を簡便化することができ、これを通じて流体動圧軸受装置１の製造コストを低廉化することができる。   In addition, the above-mentioned "the possibility that oil leakage may occur even during the oiling operation through the seal gap S can be reduced as much as possible" is synonymous with "the management range of the amount of oiling is expanded". . For reference, when using the bearing member 22 having an inner diameter of 1.5 mm and an outer diameter of 5 mm and an axial dimension of 1.5 mm, the amount of oil applied when the annular groove 13 as the lubricating oil reservoir 12 is not provided. The management range of at most 0.3 mg could be secured. On the other hand, if the annular groove 13 having an inner diameter of φ 2.75 mm, an outer diameter of 3.55 mm and a depth of 0.2 mm is formed in the bearing member 22 of the above dimensions, the management width of the oil amount is expanded to about 1.0 mg be able to. Therefore, the oiling operation can be simplified, and the manufacturing cost of the fluid dynamic bearing 1 can be reduced.

また、軸受部材２２の上端面２２ｂに潤滑油溜り１２を設けておけば、回転側（回転体２）を構成する軸受部材２２が回転するのに伴って、潤滑油溜り１２で保持した潤滑油１１を外径側に飛散させ、ラジアル軸受部Ｒのラジアル軸受隙間に供給することができる。特に、本実施形態では、潤滑油溜り１２を環状溝１３で構成していることから、ラジアル軸受隙間の周方向全域に潤滑油１１を万遍なく供給することができ、しかも環状溝１３の外径部を構成（区画形成）する内壁面を、環状溝１３の溝幅を上側に向けて漸次拡大する方向のテーパ面１３ａに形成しているので、環状溝１３で保持した潤滑油１１を、軸受部材２２の回転時に外径側に飛散させ易い。そのため、軸受部材２２を含む回転体２の回転時には、ラジアル軸受隙間に向けて効率良く潤滑油１１を供給することができる。   Further, when the lubricating oil reservoir 12 is provided on the upper end surface 22 b of the bearing member 22, the lubricating oil retained by the lubricating oil reservoir 12 along with the rotation of the bearing member 22 constituting the rotation side (rotary body 2) 11 can be scattered to the outer diameter side and supplied to the radial bearing gap of the radial bearing portion R. In particular, in the present embodiment, since the lubricating oil reservoir 12 is configured by the annular groove 13, the lubricating oil 11 can be uniformly supplied to the entire circumferential direction of the radial bearing gap, and the outside of the annular groove 13. Since the inner wall surface which constitutes the diameter portion (section formation) is formed on the tapered surface 13a in the direction of gradually expanding the groove width of the annular groove 13 upward, the lubricating oil 11 held by the annular groove 13 is At the time of rotation of the bearing member 22, it is easy to scatter to the outer diameter side. Therefore, when the rotating body 2 including the bearing member 22 rotates, the lubricating oil 11 can be efficiently supplied toward the radial bearing gap.

なお、シール部材９をハウジング７の大径内周面７ａ１に固定し、シール隙間Ｓを、軸部材２１の外周面２１ａとシール部材９の内周面９ａとの間に形成しているので、回転体２の回転時に潤滑油溜り１２で保持した潤滑油１１が外径側に飛散しても、この飛散した潤滑油１１がシール隙間Ｓを介して装置外部に漏れ出すことはない。従って、ラジアル軸受部Ｒのラジアル軸受隙間、さらにはスラスト軸受部Ｔのスラスト軸受隙間における油膜切れを防止してラジアル軸受部Ｒおよびスラスト軸受部Ｔの軸受性能を高いレベルで維持することができる。   In addition, since the seal member 9 is fixed to the large diameter inner peripheral surface 7a1 of the housing 7 and the seal gap S is formed between the outer peripheral surface 21a of the shaft member 21 and the inner peripheral surface 9a of the seal member 9, Even if the lubricating oil 11 held by the lubricating oil reservoir 12 scatters to the outer diameter side when the rotating body 2 rotates, the scattered lubricating oil 11 does not leak out of the apparatus through the seal gap S. Therefore, oil film breakage in the radial bearing gap of the radial bearing portion R and further in the thrust bearing gap of the thrust bearing portion T can be prevented, and the bearing performance of the radial bearing portion R and the thrust bearing portion T can be maintained at a high level.

また、軸受部材２２には、軸受部材２２を下方に押し付ける（スラスト他方向に支持する）外力を作用させるようにした。このようにすれば、軸受部材２２をスラスト両方向に支持することが可能となるので、スラスト軸受部Ｔのスラスト軸受隙間に形成される油膜によるスラスト一方向の荷重支持能力が過大となり、これに伴って、スラスト方向の支持精度（回転精度）が不安定化するような事態を可及的に回避することができる。本実施形態では、上記外力を、磁力で与えるようにし、しかもこの磁力を、静止側のハウジング７を保持するモータベース６に固定したステータコイル５と、軸受部材２２を含む回転体２に固定したロータマグネット４とを軸方向にずらして配置することによって与えるようにした。この種の流体動圧軸受装置１が組み込まれる各種モータは、ロータマグネット４とステータコイル５とを必須の構成部材として備える。従って、上記構成を採用すれば、上記外力を特段のコスト増を招くことなく安価に付与することができる。   In addition, an external force is applied to the bearing member 22 to press the bearing member 22 downward (support in the other direction of thrust). In this way, it is possible to support the bearing member 22 in both directions of thrust, so the ability to support the load in one direction of thrust by the oil film formed in the thrust bearing gap of the thrust bearing portion T becomes excessive. Thus, it is possible to avoid as much as possible a situation where the support accuracy (rotation accuracy) in the thrust direction becomes unstable. In the present embodiment, the external force is applied by a magnetic force, and the magnetic force is fixed to the rotor coil 2 including the stator coil 5 fixed to the motor base 6 holding the housing 7 on the stationary side and the bearing member 22. The rotor magnet 4 is provided by being axially displaced. The various motors in which the fluid dynamic bearing device 1 of this type is incorporated include the rotor magnet 4 and the stator coil 5 as essential components. Therefore, if the said structure is employ | adopted, the said external force can be provided cheaply, without causing the increase in cost in particular.

以上、本発明の実施形態に係る流体動圧軸受装置１について説明を行ったが、流体動圧軸受装置１の各部には、本発明の要旨を逸脱しない範囲で種々の変更を施すことができる。   Although the fluid dynamic bearing device 1 according to the embodiment of the present invention has been described above, various changes can be made to each part of the fluid dynamic bearing device 1 without departing from the scope of the present invention. .

例えば、軸受部材２２の上端面２２ｂに設けるべき潤滑油溜り１２は、以上で説明した環状溝１３以外にも、円弧溝、あるいは無数の凹部（ディンプル）等で構成することもできる。   For example, the lubricating oil reservoir 12 to be provided on the upper end surface 22b of the bearing member 22 can be configured by an arc groove or an infinite number of concave portions (dimples) or the like besides the annular groove 13 described above.

また、軸受部材２２を含む回転体２をラジアル方向に支持するためのラジアル軸受部は、図７に示すように、軸方向の二箇所に離間して設けることもできる（ラジアル軸受部Ｒ１，Ｒ２）。図７では、軸受部材２２の外周面２２ａの軸方向二箇所に、対向するハウジング７の小径内周面７ａ２との間にラジアル軸受隙間を形成する円筒状のラジアル軸受面を設けている。二つのラジアル軸受面には、ラジアル軸受隙間内の潤滑油１１に動圧作用を発生させるための動圧発生部（ラジアル動圧発生部）Ａ１，Ａ２がそれぞれ形成されている。上側のラジアル軸受面に形成したラジアル動圧発生部Ａ１は、互いに反対方向に傾斜し、かつ軸方向に離間した複数の動圧溝Ａａ１，Ａｂ１をヘリングボーン形状に配列して構成され、また下側のラジアル軸受面に形成したラジアル動圧発生部Ａ２は、互いに反対方向に傾斜し、かつ軸方向に離間した複数の動圧溝Ａａ２，Ａｂ２をヘリングボーン形状に配列して構成される。上側のラジアル動圧発生部Ａ１において、上側の動圧溝Ａａ１の軸方向寸法は、下側の動圧溝Ａｂ１の軸方向寸法よりも大きくなっている。一方、下側のラジアル動圧発生部Ａ２においては、上側の動圧溝Ａａ２と下側の動圧溝Ａｂ２の軸方向寸法が互いに等しく、かつ上側のラジアル動圧発生部Ａ１を構成する下側の動圧溝Ａｂ１の軸方向寸法と等しくなっている。これにより、回転体２の回転時、軸受部材２２の外周面２２ａとハウジング７の小径内周面７ａ２との間の隙間（ラジアル軸受隙間）に満たされた潤滑油１１は、スラスト軸受部Ｔのスラスト軸受隙間側に押し込まれる。   Further, radial bearing portions for supporting the rotary body 2 including the bearing members 22 in the radial direction may be provided separately at two axial positions as shown in FIG. 7 (radial bearing portions R1, R2 ). In FIG. 7, cylindrical radial bearing surfaces are provided at two axial locations of the outer peripheral surface 22 a of the bearing member 22 to form a radial bearing gap between the opposing small diameter inner peripheral surface 7 a 2 of the housing 7. Dynamic pressure generating portions (radial dynamic pressure generating portions) A1 and A2 for generating a dynamic pressure action on the lubricating oil 11 in the radial bearing gap are respectively formed on the two radial bearing surfaces. The radial dynamic pressure generating portion A1 formed on the upper radial bearing surface is configured by arranging a plurality of dynamic pressure grooves Aa1 and Ab1 which are inclined in opposite directions to each other and axially separated in a herringbone shape, and The radial dynamic pressure generating portion A2 formed on the side radial bearing surface is configured by arranging a plurality of dynamic pressure grooves Aa2 and Ab2 which are inclined in opposite directions and are axially separated from each other in a herringbone shape. In the upper radial dynamic pressure generating portion A1, the axial dimension of the upper dynamic pressure groove Aa1 is larger than the axial dimension of the lower dynamic pressure groove Ab1. On the other hand, in the lower radial dynamic pressure generating portion A2, the axial dimensions of the upper dynamic pressure groove Aa2 and the lower dynamic pressure groove Ab2 are equal to each other, and the lower radial dynamic pressure generating portion A1 is formed. It is equal to the axial dimension of the hydrodynamic groove Ab1. Thereby, the lubricating oil 11 filled in the gap (radial bearing gap) between the outer peripheral surface 22a of the bearing member 22 and the small diameter inner peripheral surface 7a2 of the housing 7 at the time of rotation of the rotating body Pushed into the thrust bearing clearance side.

また、以上で説明した実施形態では、筒部７ａとその下端開口を閉塞する底部７ｂとを一体に設けたハウジング７を使用し、ハウジング７の上端開口をシールするシール隙間Ｓを、ハウジング７（筒部７ａ）の内周面に固定したシール部材９の内周面９ａで形成するようにしたが、ハウジング７は、図８に示すように、筒部７ａとその下端開口を閉塞する底部７ｂとが別体に設けられたものを使用するようにしても構わない。その代わりに、図８では、シール隙間Ｓを形成するシール部材としてのシール部７ｃを、筒部７ａと一体に設けている。なお、このような構成を、図２に示す流体動圧軸受装置１に適用することもできる。   In the embodiment described above, the housing 7 in which the cylindrical portion 7a and the bottom portion 7b for closing the lower end opening are integrally provided is used, and the seal gap S for sealing the upper end opening of the housing 7 is The inner circumferential surface 9a of the seal member 9 fixed to the inner circumferential surface of the cylindrical portion 7a) is formed, but as shown in FIG. 8, the housing 7 is a bottom portion 7b closing the cylindrical portion 7a and its lower end opening. It is also possible to use ones separately provided. Instead, in FIG. 8, the seal portion 7 c as a seal member forming the seal gap S is provided integrally with the cylindrical portion 7 a. Such a configuration can also be applied to the fluid dynamic bearing device 1 shown in FIG.

また、以上で示した実施形態では、モータベース６の内周に、モータベース６と別体に設けたハウジング７を固定するようにしたが、ハウジング７にモータベース６に相当する部位を一体に設けることもできる（図示省略）。   Further, in the embodiment described above, the housing 7 provided separately from the motor base 6 is fixed to the inner periphery of the motor base 6, but the part corresponding to the motor base 6 is integrally fixed to the housing 7 It can also be provided (not shown).

また、以上で示した実施形態では、多孔質体からなる軸受部材２２の良好な加工性に鑑み、軸受部材２２の外周面２２ａにラジアル動圧発生部Ａ，Ａ１，Ａ２を形成したが、ラジアル動圧発生部は、対向するハウジング７の内周面７ａ２に形成しても良い。また、ラジアル軸受部は、いわゆる多円弧軸受、ステップ軸受、および波型軸受等、公知のその他の動圧軸受で構成することもできる。同様に、スラスト動圧発生部Ｂは、軸受部材２２の下端面２２ｃではなく、これに対向するハウジング７の内底面７ｂ１に形成しても良い。また、スラスト軸受部Ｔは、いわゆるステップ軸受や波型軸受等、公知のその他の動圧軸受で構成することもできる。   Further, in the embodiment described above, in consideration of the good processability of the bearing member 22 made of a porous body, the radial dynamic pressure generating portions A, A1, A2 are formed on the outer peripheral surface 22a of the bearing member 22. The dynamic pressure generating portion may be formed on the inner circumferential surface 7a2 of the opposing housing 7. The radial bearing can also be configured by other known dynamic pressure bearings such as so-called multi-arc bearings, step bearings, and wave-shaped bearings. Similarly, the thrust dynamic pressure generating portion B may be formed not on the lower end surface 22c of the bearing member 22 but on the inner bottom surface 7b1 of the housing 7 opposed thereto. Further, the thrust bearing portion T can also be configured by other known dynamic pressure bearings such as a so-called step bearing and a wave type bearing.

また、以上で示した実施形態では、ロータマグネット４とステータコイル５とを軸方向にずらして配置することにより、軸受部材２２を含む回転体２を下方に押し付ける（スラスト他方向に支持する）ための外力（磁力）を作用させるようにしたが、このような外力を回転体２に作用させるための手段は上記のものに限られない。図示は省略するが、例えば、磁性部材をロータマグネット４と軸方向に対向配置することにより、上記磁力を回転体２（ロータ３）に作用させることもできる。また、送風作用の反力としての推力が十分に大きく、この推力のみで軸受部材２２を下方に押し付けることができる場合、軸受部材２２を下方に押し付けるための外力としての磁力（磁気吸引力）は省略しても構わない。   Further, in the embodiment described above, the rotor magnet 4 and the stator coil 5 are offset in the axial direction to press the rotor 2 including the bearing member 22 downward (support in the other direction of the thrust). The external force (magnetic force) of the above is applied, but the means for applying such an external force to the rotating body 2 is not limited to the above. Although illustration is omitted, for example, the magnetic force can be applied to the rotating body 2 (the rotor 3) by arranging a magnetic member so as to face the rotor magnet 4 in the axial direction. Further, when the thrust as the reaction force of the blowing action is sufficiently large and the bearing member 22 can be pressed downward only by this thrust, the magnetic force (magnetic attraction force) as the external force for pressing the bearing member 22 downward is You may omit it.

また、以上では、羽根を有するロータ３が軸部材２１に固定される流体動圧軸受装置１に本発明を適用した場合について説明を行ったが、本発明は、羽根を有するロータ３に替えて、ディスク搭載面を有するディスクハブ、あるいはポリゴンミラーが軸部材２１に固定される流体動圧軸受装置１にも好ましく適用することができる。すなわち、本発明は、図１に示すようなファンモータのみならず、ディスク装置用のスピンドルモータや、レーザビームプリンタ（ＬＢＰ）用のポリゴンスキャナモータ等、その他の電気機器用モータに組み込まれる流体動圧軸受装置１にも好ましく適用することができる。   Further, although the case where the present invention is applied to the fluid dynamic pressure bearing device 1 in which the rotor 3 having the vanes is fixed to the shaft member 21 has been described above, the present invention is changed to the rotor 3 having the vanes The present invention can be preferably applied to the fluid dynamic bearing device 1 in which a disk hub having a disk mounting surface or a polygon mirror is fixed to the shaft member 21. That is, according to the present invention, not only the fan motor as shown in FIG. 1, but also the fluid motion to be incorporated into motors for other electric devices such as spindle motors for disk drives and polygon scanner motors for laser beam printers (LBP). It can be preferably applied to the pressure bearing device 1 as well.

１ 流体動圧軸受装置
２ 回転体
３ ロータ
４ ロータマグネット
５ ステータコイル
６ モータベース
７ ハウジング
７ａ 側部
７ｂ 底部
７ｂ１ 内底面
８ 連通路
９ シール部材
１０ 軸方向隙間
１１ 潤滑油
１２ 潤滑油溜り
１３ 環状溝
１３ａ テーパ面
２１ 軸部材
２２ 軸受部材
２２ｂ 上端面（軸方向他方側の端面）
２２ｃ 下端面（軸方向一方側の端面）
Ａ、Ａ１、Ａ２ ラジアル動圧発生部
Ｂ スラスト動圧発生部
Ｓ シール隙間
Ｒ、Ｒ１、Ｒ２ ラジアル軸受部
Ｔ スラスト軸受部 DESCRIPTION OF SYMBOLS 1 fluid dynamic bearing 2 rotor 3 rotor 4 rotor magnet 5 stator coil 6 motor base 7 housing 7 a side 7 b bottom 7 b 1 inner bottom surface 8 communication passage 9 seal member 10 axial clearance 11 lubricating oil 12 lubricating oil reservoir 13 annular groove 13a Tapered surface 21 Shaft member 22 Bearing member 22b Upper end face (end face on the other side in the axial direction)
22c Lower end face (end face on one side in the axial direction)
A, A1, A2 radial dynamic pressure generating portion B thrust dynamic pressure generating portion S seal clearance R, R1, R2 radial bearing portion T thrust bearing portion

Claims (9)

多孔質材料で形成され、軸方向両側に端面を有する回転側の軸受部材と、軸方向一方側が閉塞された有底筒状をなし、軸受部材を内周に収容した静止側のハウジングと、軸受部材の軸方向他方側の端面と対向配置され、ハウジングの開口部をシールするためのシール隙間を形成するシール部材と、軸受部材の外周面とハウジングの内周面との間に形成されるラジアル軸受隙間と、軸受部材の軸方向一方側の端面とハウジングの内底面との間に形成されるスラスト軸受隙間とを備え、ラジアル軸受隙間及びスラスト軸受隙間が潤滑油で満たされ、ラジアル軸受隙間及びスラスト軸受隙間に形成される油膜で軸受部材がラジアル方向及びスラスト方向にそれぞれ支持されると共に、互いに対向する軸受部材の軸方向他方側の端面とシール部材の軸方向一方側の端面との間に空気を含む軸方向隙間を介在させた流体動圧軸受装置において、
軸受部材の軸方向他方側の端面に潤滑油溜りを設け、潤滑油溜りの外径側の端部を、前記軸方向他方側の端面の範囲内で終端させ、
前記潤滑油溜りを画成する内壁面のうち、前記潤滑油溜りの外径部を画成する部分を、前記潤滑油溜りの開口寸法を軸方向他方側に向けて漸次拡大させる方向に傾斜したテーパ面に形成したことを特徴とする流体動圧軸受装置。 A rotating bearing member formed of a porous material and having end surfaces on both sides in the axial direction, a stationary cylindrical housing having a bottomed cylindrical shape in which one axial side is closed and the bearing member is accommodated in the inner periphery, a bearing A seal member disposed opposite to an end face on the other side in the axial direction of the member and forming a seal gap for sealing the opening of the housing, and a radial formed between the outer peripheral surface of the bearing member and the inner peripheral surface of the housing A bearing clearance and a thrust bearing clearance formed between an end face on one side in the axial direction of the bearing member and an inner bottom surface of the housing, wherein the radial bearing clearance and the thrust bearing clearance are filled with lubricating oil. The bearing member is supported in the radial direction and the thrust direction by the oil film formed in the thrust bearing gap, and the other axial end face of the bearing member facing each other and the shaft of the seal member In the fluid dynamic pressure bearing device is interposed axial clearance including air between the end face of the counter one side,
A lubricating oil reservoir is provided on the other end surface of the bearing member in the axial direction, and an outer diameter end of the lubricating oil reservoir is terminated within the range of the end surface on the other axial side ,
Of the inner wall surface defining the lubricating oil reservoir, a portion defining the outer diameter portion of the lubricating oil reservoir is inclined in a direction in which the opening dimension of the lubricating oil reservoir is gradually enlarged toward the other axial side. A fluid dynamic bearing device characterized in that it has a tapered surface . 前記潤滑油溜りを画成する内壁面のうち、前記潤滑油溜りの内径部を画成する部分を、軸方向と平行な円筒面に形成すると共に、前記潤滑油溜りの内底面を構成する平坦面を前記テーパ面と前記円筒面との間に設けた請求項１に記載の流体動圧軸受装置。 Of the inner wall surface defining the lubricating oil reservoir, a portion defining the inner diameter portion of the lubricating oil reservoir is formed into a cylindrical surface parallel to the axial direction, and a flat surface constituting the inner bottom surface of the lubricating oil reservoir. The fluid dynamic bearing according to claim 1, wherein a surface is provided between the tapered surface and the cylindrical surface . 前記潤滑油溜りを環状溝で構成し、該環状溝の溝深さを、前記軸受部材の軸方向他方側の外周縁部および内周縁部に設けた面取り部の面取り量よりも大きくした請求項１又は２に記載の流体動圧軸受装置。 The lubricating oil reservoir is constituted by an annular groove, and the groove depth of the annular groove is made larger than the chamfering amount of the chamfered portion provided on the outer peripheral edge and the inner peripheral edge on the other side in the axial direction of the bearing member. The fluid dynamic bearing device according to claim 1 or 2. 前記環状溝を、径方向に相互に分離して複数設けた請求項３に記載の流体動圧軸受装置。   The fluid dynamic pressure bearing device according to claim 3, wherein the annular grooves are provided in a plurality separated in the radial direction. 軸受部材に、軸受部材を軸方向一方側に押し付ける外力を作用させる請求項１〜４の何れか一項に記載の流体動圧軸受装置。   The fluid dynamic bearing according to any one of claims 1 to 4, wherein an external force is applied to the bearing member to press the bearing member to one side in the axial direction. シール隙間が、軸受部材を外周に固定した軸部材の外周面と、ハウジングと一体又は別体に設けたシール部材の内周面との間に形成される請求項１〜５の何れか一項に記載の流体動圧軸受装置。   The seal gap is formed between the outer peripheral surface of the shaft member which fixed the bearing member on the outer periphery, and the inner peripheral surface of the seal member provided integrally with or separately from the housing. The fluid dynamic bearing device according to claim 1. ラジアル軸受隙間内の潤滑油に動圧作用を発生させる動圧発生部を有し、この動圧発生部を、ラジアル軸受隙間内の潤滑油をスラスト軸受隙間側に押し込む形状とした請求項１〜６の何れか一項に記載の流体動圧軸受装置。   The dynamic pressure generating portion for generating a dynamic pressure action on the lubricating oil in the radial bearing gap is provided, and the dynamic pressure generating portion is configured to press the lubricating oil in the radial bearing gap into the thrust bearing gap side. The fluid dynamic bearing device according to any one of 6. 軸受部材の軸方向両側の端面を連通させる連通路を有する請求項１〜７の何れか一項に記載の流体動圧軸受装置。   The fluid dynamic pressure bearing device according to any one of claims 1 to 7, further comprising a communication passage communicating the end surfaces on both axial sides of the bearing member. 請求項１〜８の何れか一項に記載の流体動圧軸受装置と、ステータコイルと、ロータマグネットとを備えるモータ。   A motor comprising the fluid dynamic bearing according to any one of claims 1 to 8, a stator coil, and a rotor magnet.

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