JPH09317758A - Bearing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain a low cost of a bearing device provided with a pressure applying structure by a method wherein a pressure applying means for a roller bearing in place of expensive rare-earth metal stone. SOLUTION: A shaft member 1 and a bearing member 40 are assembled to be relatively rotatable through a roller bearing 3 and a dynamic pressure bearing 4 arranged axially in spaced-apart relation and at the same time a pressure chamber 14 is formed between an end surface 1a of the shaft member 1 facing against the dynamic pressure bearing 4 and the bearing member 40, thereby fluid is supplied from the dynamic pressure bearing 4 to the pressure chamber 14 when the bearing device is operated so as to apply a pressure against the roller bearing 3.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【発明の属する技術分野】本発明は、例えば磁気ディス
ク装置，光ディスク装置，レーザプリンタ，ＶＴＲ等の
映像，音響，情報機器およびその他の精密回転機器に用
いられる軸受装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing device used for video, audio, information equipment, and other precision rotating equipment such as a magnetic disk drive, an optical disk drive, a laser printer, and a VTR.

【０００２】[0002]

【従来の技術】従来のこの種の軸受装置としては、例え
ば図６に示すような磁気ディスク装置のスピンドルモー
タに組み込まれたものが知られている（特開平６−３１
１７０２号公報）。この軸受装置は、図外の基台に固定
される軸部材ｂと、図示しない磁気ディスクが搭載され
て回転駆動部ｃで回転駆動されるスリーブ部材ｄとの間
に、軸方向に互いに離間させて転がり軸受（玉軸受）ｅ
及び動圧軸受ｆを配設してあり、その動圧軸受ｆの近傍
の軸部材ｂに第１の永久磁石ｇを固定するとともに、そ
の第１の永久磁石ｇに同極で対向して反発する第２の永
久磁石ｈをスリーブ部材ｄに固定し、第１の永久磁石ｇ
と第２の永久磁石ｈとの反発力の少なくとも一部の力を
転がり軸受ｅの方向に作用させることにより、当該転が
り軸受ｅに予圧を作用させるようになっている。2. Description of the Related Art As a conventional bearing device of this type, there is known a bearing device incorporated into a spindle motor of a magnetic disk device as shown in FIG. 6 (Japanese Patent Laid-Open No. 6-31).
No. 1702). In this bearing device, a shaft member b fixed to a base (not shown) and a sleeve member d on which a magnetic disk (not shown) is mounted and which is driven to rotate by a rotation drive unit c are separated from each other in the axial direction. Rolling bearing (ball bearing) e
And a dynamic pressure bearing f. The first permanent magnet g is fixed to the shaft member b in the vicinity of the dynamic pressure bearing f, and the first permanent magnet g is opposed to the first permanent magnet g with the same pole and repels. The second permanent magnet h is fixed to the sleeve member d, and the first permanent magnet g
By applying at least a part of the repulsive force of the second permanent magnet h in the direction of the rolling bearing e, a preload is applied to the rolling bearing e.

【０００３】[0003]

【発明が解決しようとする課題】しかしながら、上記従
来の軸受装置においては、玉軸受ｅに予圧を与えるため
に、動圧軸受ｆの上部近傍に第１の永久磁石ｇと第２の
永久磁石ｈとを対向配置して反発型磁気軸受または吸引
型磁気軸受を構成するという手段を講じている。したが
って、玉軸受ｅに十分な予圧を付与するためには、高価
な希土類磁石のような反発力または吸引力が大きな磁石
を使用することが必要であり、低コスト化が難しいとい
う問題点がある。However, in the above conventional bearing device, in order to apply a preload to the ball bearing e, the first permanent magnet g and the second permanent magnet h are provided in the vicinity of the upper portion of the dynamic pressure bearing f. A means for forming a repulsion type magnetic bearing or a suction type magnetic bearing by arranging and are opposed to each other is taken. Therefore, in order to apply a sufficient preload to the ball bearing e, it is necessary to use a magnet having a large repulsive force or attractive force, such as an expensive rare earth magnet, and it is difficult to reduce the cost. .

【０００４】そこで本発明は、このような従来の軸受装
置の問題点に着目してなされたもので、高価な希土類磁
石に代わる玉軸受への予圧付与手段を設けることによ
り、予圧付与構造を備えた軸受装置の低コスト化を図る
ことを目的とする。Therefore, the present invention has been made by paying attention to the problems of the conventional bearing device, and is provided with a preload applying structure by providing a preload applying means to the ball bearing instead of the expensive rare earth magnet. The purpose is to reduce the cost of the bearing device.

【０００５】[0005]

【課題を解決するための手段】上記目的を達成するた
め、本発明の請求項１にかかる軸受装置は、軸部材と軸
受部材とを、軸方向に間隔を置いて配置した玉軸受と動
圧軸受とを介して相対回転自在に組み立てると共に、前
記軸部材の動圧軸受側の端面と軸受部材との間に圧力室
を設け、その圧力室に軸受装置の作動時に前記動圧軸受
から流体を供給して前記玉軸受に予圧を付与することを
特徴とする。In order to achieve the above object, a bearing device according to claim 1 of the present invention comprises a ball bearing in which a shaft member and a bearing member are axially spaced from each other, and a dynamic pressure bearing. It is assembled so as to be relatively rotatable via a bearing, and a pressure chamber is provided between an end surface of the shaft member on the dynamic pressure bearing side and the bearing member, and fluid is supplied from the dynamic pressure bearing to the pressure chamber during operation of the bearing device. It is characterized in that it is supplied to apply a preload to the ball bearing.

【０００６】このように構成した本発明の軸受装置にあ
っては、その回転作動により動圧軸受の動圧発生用の溝
の潤滑流体に発生した圧力が、軸部材の端面に臨む圧力
室に供給される。その圧力で軸部材を軸方向に加圧して
変位させ玉軸受に予圧を付与する。したがって、軸受装
置の外部に別途に玉軸受用の予圧付与手段を設ける必要
はない。In the bearing device of the present invention configured as described above, the pressure generated in the lubricating fluid in the groove for generating the dynamic pressure of the dynamic pressure bearing by the rotation operation thereof is set in the pressure chamber facing the end surface of the shaft member. Supplied. The pressure causes the shaft member to be axially pressed and displaced to apply a preload to the ball bearing. Therefore, it is not necessary to separately provide preload applying means for the ball bearing outside the bearing device.

【０００７】[0007]

【発明の実施の形態】以下、本発明の実施の形態を図面
を参照して説明する。なお、同等の機能を有する部材に
は、各図において同一の符号を付して示してある。Embodiments of the present invention will be described below with reference to the drawings. It should be noted that members having equivalent functions are denoted by the same reference numerals in each drawing.

【０００８】先ず構成を説明すると、図１は本発明の軸
受装置２０の第１の実施形態の断面図である。円筒状の
軸部材１とスリーブ部材２とが、軸方向に間隔を置いて
配置した深溝玉軸受（以下、単に玉軸受という）３と動
圧軸受４とを介して相対回転自在に組み立てられてい
る。玉軸受３は、その内輪３ｎの内周面が軸部材１の外
周面に嵌着され、複数個の玉３ｔを挟んで内輪３ｎに対
向する外輪３ｇの外周面がスリーブ部材２の下部に設け
た大径の円筒孔５の内周面に嵌着している。動圧軸受４
は、軸部材１の一端（上端）面１ａの近傍の軸部材の外
周面がラジアル外周面７とされ、これにラジアル軸受隙
間８を介して対向するスリーブ部材２の上部円筒孔９の
内周面がラジアル軸受面１０とされ、そのラジアル軸受
面１０に例えばスパイラル状の動圧発生用の溝１１がボ
ール転造等の手段で形成されている。First, the structure will be described. FIG. 1 is a sectional view of a first embodiment of a bearing device 20 of the present invention. A cylindrical shaft member 1 and a sleeve member 2 are relatively rotatably assembled via a deep groove ball bearing (hereinafter, simply referred to as a ball bearing) 3 and a dynamic pressure bearing 4 which are spaced apart in the axial direction. There is. In the ball bearing 3, the inner peripheral surface of the inner ring 3n is fitted to the outer peripheral surface of the shaft member 1, and the outer peripheral surface of the outer ring 3g facing the inner ring 3n with a plurality of balls 3t interposed is provided in the lower portion of the sleeve member 2. It is fitted on the inner peripheral surface of the large-diameter cylindrical hole 5. Dynamic bearing 4
The outer peripheral surface of the shaft member near the one end (upper end) surface 1a of the shaft member 1 is a radial outer peripheral surface 7, and the inner peripheral surface of the upper cylindrical hole 9 of the sleeve member 2 facing the radial outer peripheral surface 7 with a radial bearing gap 8 therebetween. The surface is a radial bearing surface 10, and a groove 11 for generating, for example, a spiral dynamic pressure is formed on the radial bearing surface 10 by means of ball rolling or the like.

【０００９】前記スリーブ部材２の上部円筒孔９は、軸
部材１の動圧軸受４側の端面１ａに軸方向隙間空間Ｓを
介して対向配置するとともに、加締め等の手段でスリー
ブ部材２に固着した蓋部材１３で閉じ、当該隙間空間Ｓ
を圧力室１４として構成している。従って、スリーブ部
材２と蓋部材１３とは軸受部材４０を構成する。The upper cylindrical hole 9 of the sleeve member 2 is disposed opposite to the end surface 1a of the shaft member 1 on the side of the dynamic pressure bearing 4 via the axial clearance space S, and is attached to the sleeve member 2 by means of caulking or the like. It is closed by the fixed lid member 13, and the space S
Is configured as the pressure chamber 14. Therefore, the sleeve member 2 and the lid member 13 form a bearing member 40.

【００１０】スリーブ部材２の下部の玉軸受３側の円筒
孔５の開放端には磁性流体シール１５を付設して、当該
玉軸受３から発生するダストの外部放出を防止してい
る。次にこの実施形態の作用を述べる。A magnetic fluid seal 15 is attached to the open end of the cylindrical hole 5 on the side of the ball bearing 3 on the lower side of the sleeve member 2 to prevent the dust generated from the ball bearing 3 from being discharged to the outside. Next, the operation of this embodiment will be described.

【００１１】以上のように構成した軸受装置２０は、軸
受装置の作動時すなわち軸部材１と軸受部材４０とが相
対回転作動すると、動圧軸受４の動圧発生用の溝１１内
の予め供給されている潤滑流体に圧力が発生して、軸部
材１とスリーブ部材２とがラジアル軸受隙間８を介して
互いに非接触で支持され、スリーブ部材２の軸部材１に
対する傾き及び偏心が防止されるのみならず、当該潤滑
流体の圧力が圧力室１４内の潤滑流体にも伝達されて軸
部材１の端面１ａを図の下方（玉軸受３側）へ押圧す
る。この押圧力は軸部材１を介して伝達されてその軸部
材１に嵌着された玉軸受３の内輪３ｎに負荷されて玉３
ｔに予圧力が付与され、玉軸受３は軸部材１またはスリ
ーブ部材２に負荷されるラジアル荷重とスラスト荷重と
を支持する。In the bearing device 20 configured as described above, when the bearing device is operated, that is, when the shaft member 1 and the bearing member 40 are relatively rotated, the bearing device 20 is previously supplied into the groove 11 for generating the dynamic pressure of the dynamic pressure bearing 4. A pressure is generated in the lubricating fluid being retained, the shaft member 1 and the sleeve member 2 are supported in a non-contact manner with each other through the radial bearing gap 8, and inclination and eccentricity of the sleeve member 2 with respect to the shaft member 1 are prevented. Not only that, the pressure of the lubricating fluid is also transmitted to the lubricating fluid in the pressure chamber 14 to press the end surface 1a of the shaft member 1 downward (the ball bearing 3 side) in the drawing. This pressing force is transmitted through the shaft member 1 and is applied to the inner ring 3n of the ball bearing 3 fitted to the shaft member 1 to load the ball 3
A preload is applied to t, and the ball bearing 3 supports the radial load and the thrust load applied to the shaft member 1 or the sleeve member 2.

【００１２】かくして本実施形態によれば、例えば高価
な希土類磁石等を用いるなどして別途に玉軸受予圧付与
手段を設けることなく、玉軸受３に所要の剛性を与える
ことが可能であり、軸受装置全体の低コスト化が実現で
きる。しかも、軸部材１とスリーブ部材２との間に軸方
向に間隔を置いて介在する二組の軸受は、一方のみが玉
軸受３で、他方はラジアル軸受隙間８を有する動圧軸受
４としたので、双方の軸受にともに玉軸受３を使用した
軸受装置の場合に比べて、軸受の組立誤差に起因するミ
スアライメントの影響を受けにくく、その結果、本軸受
装置２０をスピンドルモータに組み込んだ場合の当該モ
ータの非回転同期成分の振れを、従来の軸受装置より小
さくすることができるという効果をも奏する。因みに、
本願発明者等の研究結果によれば、スピンドルモータの
非回転同期成分の振れの主な原因は、玉軸受単体の非回
転同期成分の振れよりも、２個の玉軸受の組立誤差に起
因するミスアライメントによる影響が大きいという知見
が得られている。Thus, according to this embodiment, it is possible to give the required rigidity to the ball bearing 3 without separately providing the ball bearing preload applying means by using an expensive rare earth magnet or the like. The cost of the entire device can be reduced. Moreover, of the two sets of bearings which are interposed between the shaft member 1 and the sleeve member 2 at a distance in the axial direction, only one is the ball bearing 3 and the other is the dynamic pressure bearing 4 having the radial bearing gap 8. Therefore, as compared with the case of a bearing device that uses the ball bearing 3 for both bearings, it is less susceptible to misalignment due to an assembly error of the bearings, and as a result, when the present bearing device 20 is incorporated in a spindle motor. Also, it is possible to reduce the swing of the non-rotational synchronous component of the motor as compared with the conventional bearing device. By the way,
According to the research results of the inventors of the present application, the main cause of the runout of the non-rotational synchronization component of the spindle motor is due to the assembly error of the two ball bearings rather than the runout of the non-rotational synchronization component of the ball bearing unit. It has been found that the effect of misalignment is large.

【００１３】ここで、玉軸受３と動圧軸受４とにそれぞ
れ用いる潤滑流体の種類及びそのシールについて説明す
る。両軸受の潤滑流体の種類は、同一のものでも、異な
るものでもよい。例えば 玉軸受３にグリースを使用し、動圧軸受４には潤滑油
を使用する。 玉軸受３及び動圧軸受４の双方にグリースを使用す
る。 玉軸受３及び動圧軸受４の双方に潤滑油を使用する。 玉軸受３及び動圧軸受４の双方に磁性流体を使用す
る。 等、種々の対応が可能である。The types of lubricating fluid used for the ball bearing 3 and the dynamic pressure bearing 4 and their seals will be described below. The type of lubricating fluid for both bearings may be the same or different. For example, grease is used for the ball bearing 3 and lubricating oil is used for the dynamic pressure bearing 4. Grease is used for both the ball bearing 3 and the dynamic pressure bearing 4. Lubricating oil is used for both the ball bearing 3 and the dynamic pressure bearing 4. Magnetic fluid is used for both the ball bearing 3 and the dynamic pressure bearing 4. Various other measures are possible.

【００１４】，．のケースのように、双方の軸受
に同一の潤滑流体を使用した場合は、玉軸受３と動圧軸
受４との潤滑流体同士が混じり合って潤滑特性が変化し
てしまうという危険性を防止できる。また、のケース
のように、双方の軸受に異なる潤滑流体を使用した場合
は、それぞれの軸受に最適な潤滑流体を選ぶことが可能
となり、きめ細かな軸受性能の設計が可能となる。,. When the same lubricating fluid is used for both bearings as in the case of No. 1, it is possible to prevent the risk that the lubricating fluids of the ball bearing 3 and the dynamic pressure bearing 4 are mixed with each other to change the lubricating characteristics. . Also, when different lubricating fluids are used for both bearings as in the case of (1), it is possible to select the optimal lubricating fluid for each bearing, and it is possible to design fine bearing performance.

【００１５】更に、本実施形態のように、スリーブ部材
２の下部の玉軸受３側の開放端に磁性流体シール１５を
付設した場合に、上記のケースの如くに玉軸受３及び
動圧軸受４の双方とも磁性流体を使用して潤滑すると、
潤滑流体の混合による潤滑特性変化や軸受装置外への潤
滑流体の漏れが無くなるので好ましい。Further, when the magnetic fluid seal 15 is attached to the lower end of the sleeve member 2 on the side of the ball bearing 3 as in the present embodiment, the ball bearing 3 and the dynamic pressure bearing 4 as in the above case. If both are lubricated using magnetic fluid,
This is preferable because there is no change in lubrication characteristics due to mixing of the lubricating fluid and leakage of the lubricating fluid to the outside of the bearing device.

【００１６】また、軸受部材４０には動圧軸受４の軸受
すき間８から玉軸受３の側へはみ出す潤滑流体を表面張
力により保持するためのテーパ部１６が、ラジアル軸受
面１０の玉軸受３側の端に隣接して設けられており、こ
れにより、潤滑流体の漏れと周囲への飛散が防止され
る。そのテーパ部１６の軸心に対するテーパ角度θは２
°〜４５°の範囲が好ましい。テーパ角度θが２°未満
ではテーパ部１６に保持できる潤滑流体の量が少なくな
り、一方テーパ角度θが４５°を超えると軸受装置の回
転時の遠心力によって潤滑流体が飛散し易くなる場合が
ある。回転数が３６００ｒｐｍよりも高速の場合には、
テーパ部１６の軸心に対するテーパ角度θを３０°以下
に設定すると潤滑流体の飛散防止効果がより顕著にな
る。Further, the bearing member 40 has a taper portion 16 for holding the lubricating fluid protruding from the bearing clearance 8 of the dynamic pressure bearing 4 toward the ball bearing 3 side by surface tension, and the taper portion 16 of the radial bearing surface 10 on the ball bearing 3 side. Is provided adjacent to the end of the lubricating oil, thereby preventing the lubricating fluid from leaking and splashing to the surroundings. The taper angle θ of the tapered portion 16 with respect to the axis is 2
The range of ° to 45 ° is preferred. If the taper angle θ is less than 2 °, the amount of lubricating fluid that can be retained in the taper portion 16 is small, whereas if the taper angle θ exceeds 45 °, the lubricating fluid may be easily scattered by the centrifugal force when the bearing device rotates. is there. When the rotation speed is higher than 3600 rpm,
When the taper angle θ of the tapered portion 16 with respect to the axis is set to 30 ° or less, the effect of preventing the lubricating fluid from scattering becomes more remarkable.

【００１７】なお、ラジアル軸受面１０とテーパ部１６
とラジアル軸受面１０及びテーパ部１６に対向する軸部
材１の外周面との少なくとも一方に、潤滑流体をはじく
性質を持つ撥油剤を前もって被着しておくと、その撥油
剤にはじかれた潤滑流体が毛細管現象により軸受すき間
８へ移行して外部へ飛散しなくなり、軸受すき間８から
の潤滑流体の流出・飛散の防止を確実に行うことができ
る利点がある。具体的には、例えば潤滑流体にフッ素油
を用いる場合には、撥油剤としてシリコン油を予め被着
しておき、潤滑流体に鉱油や合成油を用いる場合には、
撥油剤としてフッ素油系改質膜を被着しておくとよい。Incidentally, the radial bearing surface 10 and the taper portion 16
If an oil repellent having a property of repelling a lubricating fluid is applied to at least one of the radial bearing surface 10 and the outer peripheral surface of the shaft member 1 facing the taper portion 16 in advance, the lubrication repelled by the oil repellent is applied. There is an advantage that the fluid moves to the bearing gap 8 due to the capillary phenomenon and does not scatter to the outside, and the outflow / scattering of the lubricating fluid from the bearing gap 8 can be reliably prevented. Specifically, for example, when fluorine oil is used as the lubricating fluid, silicon oil is previously applied as the oil repellent, and when mineral oil or synthetic oil is used as the lubricating fluid,
It is advisable to deposit a modified fluorinated oil film as the oil repellent.

【００１８】図２は、本発明の軸受装置の第２の実施形
態の断面図である。この実施形態の軸受装置２０は、玉
軸受３の内輪３ｎを取り除いて、軸部材１の外周面に直
接に玉３ｔの軌道面３ｋを形成している。内輪３ｎを省
いたことにより軸受装置全体の外径を小さくすることが
できる利点がある。なお、スリーブ部材２は、加工性と
摺動性の良い快削黄銅やりん青銅などの軟質金属製とし
て、スリーブ部材２の内周面におけるラジアル軸受面１
０に動圧発生用の溝１１を容易に塑性加工できるように
するとともに、動圧軸受４の起動時に発生するラジアル
軸受面１０とラジアル外周面７との接触による摩耗の緩
和を図っている。その動圧軸受４のラジアル軸受面１０
の動圧発生用の溝１１は、非対称なヘリングボーン状の
溝としてラジアル負荷容量を高めている。また、スリー
ブ部材２の内周面の上端部には円筒ころ部材１７を圧入
して、軸部材１の端面１ａと円筒ころ部材１７との間に
軸方向すき間の圧力室１４を形成している。従って、ス
リーブ部材２と円筒ころ部材１７とは軸受部材４０を構
成する。また、この場合の玉軸受３の下端のシールは、
外輪３ｇに取り付けた一般的な玉軸受用のシールド又は
シール３ｓで行っている。FIG. 2 is a sectional view of a second embodiment of the bearing device of the present invention. In the bearing device 20 of this embodiment, the inner ring 3n of the ball bearing 3 is removed, and the raceway surface 3k of the ball 3t is directly formed on the outer peripheral surface of the shaft member 1. There is an advantage that the outer diameter of the entire bearing device can be reduced by omitting the inner ring 3n. The sleeve member 2 is made of a soft metal such as free-cutting brass or phosphor bronze having good workability and slidability, and the radial bearing surface 1 on the inner peripheral surface of the sleeve member 2 is used.
The groove 11 for generating the dynamic pressure can be easily plastically machined to 0, and the wear caused by the contact between the radial bearing surface 10 and the radial outer peripheral surface 7 generated when the dynamic pressure bearing 4 is started is mitigated. The radial bearing surface 10 of the dynamic pressure bearing 4
The dynamic pressure generating groove 11 is an asymmetrical herringbone groove to enhance the radial load capacity. A cylindrical roller member 17 is press-fitted into the upper end portion of the inner peripheral surface of the sleeve member 2 to form a pressure chamber 14 between the end surface 1a of the shaft member 1 and the cylindrical roller member 17 in the axial direction. . Therefore, the sleeve member 2 and the cylindrical roller member 17 form a bearing member 40. In addition, the seal at the lower end of the ball bearing 3 in this case is
This is done with a general ball bearing shield or seal 3s attached to the outer ring 3g.

【００１９】この実施形態の軸受装置における上記以外
の作用効果は、第１の実施形態のものと同様である。続
いて、本発明の軸受装置の第３の実施形態を、スピンド
ルモータの断面図である図３を参照して説明する。The function and effect of the bearing device of this embodiment other than those described above are the same as those of the first embodiment. Next, a third embodiment of the bearing device of the present invention will be described with reference to FIG. 3, which is a sectional view of a spindle motor.

【００２０】この実施形態は、本発明に係る軸受装置２
０を実際のＨＤＤスピンドルモータ２１に、軸部材固
定，軸受部材回転で組み込んだもので、当該軸受装置２
０の軸部材１が基台２２に固定され、その軸部材１の上
部に配設したスリーブ部材２は図示されない磁気ディス
クが搭載されるハブ（回転体）２３の内周に一体に嵌着
されている。また、軸部材１の下部には玉軸受３が、そ
の内輪３ｎを軸部材１に嵌着しその外輪３ｇをハブ（回
転体）２３の内周面に嵌着することにより、内輪固定外
輪回転で装着されている。This embodiment is a bearing device 2 according to the present invention.
0 is installed in the actual HDD spindle motor 21 by fixing the shaft member and rotating the bearing member.
The shaft member 1 of 0 is fixed to the base 22, and the sleeve member 2 disposed above the shaft member 1 is integrally fitted to the inner periphery of the hub (rotating body) 23 on which a magnetic disk (not shown) is mounted. ing. Further, the ball bearing 3 is fitted to the lower portion of the shaft member 1 by fitting the inner ring 3n thereof to the shaft member 1 and the outer ring 3g thereof to the inner peripheral surface of the hub (rotating body) 23, thereby rotating the inner ring fixed outer ring. It is installed in.

【００２１】前記スリーブ部材２の内周面のラジアル軸
受面１０には、スパイラル状の動圧発生用の溝１１がボ
ール転造等の手段で形成され、またスリーブ部材２の内
周面には、ラジアル軸受面１０の玉軸受３側の端に隣接
して、テーパ部１６が設けられている。また、スリーブ
部材２の内周面上端部には円筒ころ部材１７が圧入され
て、軸部材１の上端面１ａとの間に軸方向すき間の圧力
室１４が設けられている。従って、ハブ２３とスリーブ
部材２と円筒ころ部材１７とは軸受部材４０を構成す
る。The radial bearing surface 10 on the inner peripheral surface of the sleeve member 2 is formed with a spiral dynamic pressure generating groove 11 by means of ball rolling or the like, and the inner peripheral surface of the sleeve member 2 is formed. A taper portion 16 is provided adjacent to the end of the radial bearing surface 10 on the ball bearing 3 side. A cylindrical roller member 17 is press-fitted into the upper end of the inner peripheral surface of the sleeve member 2, and a pressure chamber 14 is provided between the upper end surface 1a of the shaft member 1 and the axial gap. Therefore, the hub 23, the sleeve member 2, and the cylindrical roller member 17 form a bearing member 40.

【００２２】前記ハブ２３の下面には環状の凹部２４が
設けられ、この凹部２４は、スリーブ部材２及び玉軸受
３の外輪３ｇが嵌着されたハブ最内周面２３ｎとハブ最
外周面２３ｇとの間に位置しており、その環状の凹部２
４の内周面２４ｎに、ロータ（マグネット）２５が固定
され、一方、当該環状の凹部２４内に突き出して形成さ
れている基台２２の環状の突部２７の外周面２７ｇに
は、ロータ２５にエアギャップを隔てて半径方向に対向
に配されたステータ２８が固定されてモータＭが構成さ
れている。An annular recess 24 is provided on the lower surface of the hub 23. The recess 24 has an innermost hub surface 23n and an outermost hub surface 23g on which the outer ring 3g of the sleeve member 2 and the ball bearing 3 are fitted. And the annular recess 2 located between
The rotor (magnet) 25 is fixed to the inner peripheral surface 24n of the rotor 4, while the rotor 25 is attached to the outer peripheral surface 27g of the annular projecting portion 27 of the base 22 formed so as to project into the annular concave portion 24. A motor M is configured by fixing stators 28, which are arranged to face each other in the radial direction across an air gap.

【００２３】以上のように構成されたスピンドルモータ
２１の作動は次の通りである。前記モータＭのステータ
２８のコイルに通電すると、ハブ２３が駆動される。ハ
ブ２３は玉軸受３の玉３ｔ及び動圧軸受４のラジアル軸
受すき間８の流体膜を介して軸部材１に回転自在に支持
されているため、軸部材１の回りに回転駆動される。か
かる駆動時には、動圧軸受４の動圧発生用の溝１１のポ
ンピング作用により、軸受すき間８内の潤滑流体に動圧
が発生して、軸受装置２０のスリーブ部材２が軸部材１
に非接触で回転する。そして、軸受すき間８内の潤滑流
体で発生した動圧の伝達で、圧力室１４内の潤滑流体の
圧力が高まり、ハブ２３が上方向に押圧される結果、ハ
ブ最内周面２３ｎに嵌着された玉軸受の外輪３ｇに上向
きの力が作用して玉３ｔに予圧が付与されることとな
る。The operation of the spindle motor 21 constructed as described above is as follows. When the coil of the stator 28 of the motor M is energized, the hub 23 is driven. The hub 23 is rotatably supported by the shaft member 1 through the fluid film in the ball 3t of the ball bearing 3 and the radial bearing gap 8 of the dynamic pressure bearing 4, and therefore is driven to rotate around the shaft member 1. During such driving, a dynamic pressure is generated in the lubricating fluid in the bearing clearance 8 by the pumping action of the dynamic pressure generating groove 11 of the dynamic pressure bearing 4, and the sleeve member 2 of the bearing device 20 causes the shaft member 1 to move.
Rotate without contact. The transmission of the dynamic pressure generated by the lubricating fluid in the bearing clearance 8 increases the pressure of the lubricating fluid in the pressure chamber 14 and pushes the hub 23 upward. As a result, the hub 23 is fitted on the innermost peripheral surface 23n. The upward force acts on the outer ring 3g of the ball bearing thus set, and a preload is applied to the ball 3t.

【００２４】この予圧で、玉軸受３は剛性が高まり、軸
部材１または軸受部材４０に負荷されるラジアル荷重と
スラスト荷重とを支持する。かくしてこの第３の実施形
態にあっても、別途に玉軸受予圧付与手段を設けること
なく玉軸受３に所要の剛性を与えることができてスピン
ドルモータ２１の低コスト化が実現する。しかも、軸部
材１と軸受部材４０との間に介在する二組の軸受は、一
方が玉軸受３で他方はラジアル軸受隙間８を有する動圧
軸受４であるから、軸受の組立誤差に起因するミスアラ
イメントの影響を受けにくく、スピンドルモータ２１の
非回転同期成分の振れが抑制されてハブ２３ひいては磁
気ディスクの安定した回転が保証されるという効果をも
奏する。With this preload, the rigidity of the ball bearing 3 is increased, and the ball bearing 3 supports the radial load and the thrust load applied to the shaft member 1 or the bearing member 40. Thus, also in the third embodiment, the ball bearing 3 can be provided with a required rigidity without separately providing the ball bearing preloading means, and the cost of the spindle motor 21 can be reduced. Moreover, since the two sets of bearings interposed between the shaft member 1 and the bearing member 40 are the dynamic bearing 4 having the ball bearing 3 and the radial bearing gap 8 on the other side, the bearing assembly error results. The effects of misalignment are less likely to occur, and the shake of the non-rotational synchronization component of the spindle motor 21 is suppressed, so that stable rotation of the hub 23 and thus of the magnetic disk is ensured.

【００２５】また、スリーブ部材２の内周面のテーパ部
１６で、動圧軸受４の軸受すき間８からはみ出す潤滑流
体を表面張力の作用により保持するから、潤滑流体が動
圧軸受４から漏れ出し、玉軸受３及び環状の凹部２４を
通過してハブ２３の外部に飛散し、これにより回転中の
磁気ヘッドの汚損される事態を回避することができる。Further, the tapered portion 16 on the inner peripheral surface of the sleeve member 2 holds the lubricating fluid protruding from the bearing gap 8 of the dynamic pressure bearing 4 by the action of surface tension, so that the lubricating fluid leaks from the dynamic pressure bearing 4. It is possible to avoid the situation where the ball head 3 and the annular recess 24 pass through and scatter to the outside of the hub 23, thereby damaging the rotating magnetic head.

【００２６】図４に、本発明の軸受装置の第４の実施形
態を示す。この実施形態も、上記第３の実施形態の場合
と同じく、本発明に係る軸受装置２０を実際のＨＤＤス
ピンドルモータ２１に組み込んだ例である。しかしこの
場合はスリーブ部材固定，軸部材回転とした点が異なっ
ており、第２の実施形態に示した軸受装置２０を倒立さ
せて組み込んだタイプである。すなわち、基台２２に
は、スリーブ部材２がねじ止め等の手段で固定され、軸
部材１の方はカップを伏せた形状のハブ２３の軸心を通
してハブ２３に一体的に嵌着されている。前記固定スリ
ーブ部材２の上部の内周面には玉軸受３の外輪３ｇが嵌
入され、玉軸受３の内輪３ｎは取り除いて、軸部材１の
外周面に直接に玉３ｔの軌道面３ｋが形成してある。ま
た、スリーブ部材２の下部の内周面は動圧軸受４のラジ
アル軸受面１０であり、その面に例えば非対称なヘリン
グボーン状の動圧発生用の溝１１が形成され、軸部材１
の下部のラジアル外周面７に軸受すき間８を介して対向
している。圧力室１４は、スリーブ部材２の内周下端に
平板３１をねじ等で固着して開口を塞ぎ形成されてい
る。従って、スリーブ部材２と平板３１とが軸受部材４
０を構成する。また、スリーブ部材２の上部の開口端部
に、磁性流体シール１５を配設して軸部材１の外周面と
の間のすき間を磁性流体でシールし、玉軸受３内の潤滑
剤等のスリーブ部材２の外部への飛散を防止している。FIG. 4 shows a fourth embodiment of the bearing device of the present invention. This embodiment is also an example in which the bearing device 20 according to the present invention is incorporated in an actual HDD spindle motor 21 as in the case of the third embodiment. However, this case is different in that the sleeve member is fixed and the shaft member is rotated, and the bearing device 20 shown in the second embodiment is installed upside down. That is, the sleeve member 2 is fixed to the base 22 by means such as screwing, and the shaft member 1 is integrally fitted to the hub 23 through the shaft center of the hub 23 having a cup-down shape. . The outer ring 3g of the ball bearing 3 is fitted into the upper inner peripheral surface of the fixed sleeve member 2, the inner ring 3n of the ball bearing 3 is removed, and the raceway surface 3k of the ball 3t is formed directly on the outer peripheral surface of the shaft member 1. I am doing it. The inner peripheral surface of the lower portion of the sleeve member 2 is the radial bearing surface 10 of the dynamic pressure bearing 4, and for example, an asymmetric herringbone-shaped groove 11 for generating dynamic pressure is formed on the surface, and the shaft member 1
The radial outer peripheral surface 7 of the lower part of the bearing. The pressure chamber 14 is formed by fixing a flat plate 31 to the lower end of the inner circumference of the sleeve member 2 with screws or the like to close the opening. Therefore, the sleeve member 2 and the flat plate 31 form the bearing member 4
0. Further, a magnetic fluid seal 15 is provided at the upper open end of the sleeve member 2 to seal the gap between the outer peripheral surface of the shaft member 1 with the magnetic fluid, and a sleeve such as a lubricant in the ball bearing 3 is provided. The member 2 is prevented from scattering to the outside.

【００２７】ハブ２３を軸部材１と一体回転させるモー
タＭについては、軸受装置のスリーブ部材２の外周面に
ステータ２８を固定し、そのステータ２８にエアギャッ
プを隔てて半径方向対向に配設するロータ２５がカップ
状のハブ２３の内周面２３ｎに固定されている。In the motor M for integrally rotating the hub 23 with the shaft member 1, the stator 28 is fixed to the outer peripheral surface of the sleeve member 2 of the bearing device, and the stator 28 is arranged radially opposite to each other with an air gap. The rotor 25 is fixed to the inner peripheral surface 23n of the cup-shaped hub 23.

【００２８】この実施形態によれば、玉軸受３の内輪３
ｎを省いたのでスリーブ部材２の外径が小さくなり、装
置を小型化できる利点がある。その他の作用効果は上記
第３の実施形態の場合と同様である。According to this embodiment, the inner ring 3 of the ball bearing 3 is
Since n is omitted, there is an advantage that the outer diameter of the sleeve member 2 is reduced and the device can be downsized. Other functions and effects are similar to those of the third embodiment.

【００２９】更に図５に、本発明の軸受装置の第５の実
施形態を示す。この実施形態は、本発明に係る軸受装置
２０をＨＤＤスピンドルモータ２１にスリーブ部材固
定，軸部材回転で組み込んであるが、軸部材１をハブ２
３から上方へ突き出す長さにするとともに玉軸受３をハ
ブ２３の外部に配置し、その長い軸部材１の両端部を軸
受で支持した点が上記各実施形態とは異なっている。す
なわち、スピンドルモータの基台２２の軸心部に貫通孔
３２を形成して、その貫通孔３２の内周面にスリーブ部
材２を挿入固着している。そのスリーブ部材２は加工性
と摺動性に優れた快削黄銅やりん青銅等の軟質金属製の
ものとし、その内面のラジアル軸受面１０に動圧発生用
の溝１１をボール転造等の塑性加工により形成して動圧
軸受４を構成してある。前記基台２２は、取付板３３に
ボルト止めして固定してあり、前記スリーブ部材２の下
部開放口はボール３４を嵌合して塞がれている。軸部材
１は下端側がスリーブ部材２に挿入され、上端側はＨＤ
Ｄスピンドルモータ２１の固定部材である取付板３３に
固定した蓋２１ｆを貫通している。その蓋２１ｆに、玉
軸受３を内蔵した軸受ケース３５が取付けられており、
軸部材１の上端部は当該玉軸受３により回転自在に支持
されている。従って、ボール３４，スリーブ部材２，基
台２２，取付板３３，軸受ケース３５及び蓋２１ｆは軸
受部材４０を構成する。軸部材１の下部のラジアル外周
面７は、軸受すき間８を介してスリーブ部材２のラジア
ル軸受面１０に対向配置され、軸部材１の平面状の下端
面１ｂと前記ボール３４との間には若干の軸方向すき間
を介在させて圧力室１４が設けられている。この実施形
態におけるモータＭの配置は上記第４の実施形態の場合
と同じである。Further, FIG. 5 shows a fifth embodiment of the bearing device of the present invention. In this embodiment, the bearing device 20 according to the present invention is incorporated in the HDD spindle motor 21 by fixing the sleeve member and rotating the shaft member.
3, the ball bearing 3 is disposed outside the hub 23, and both ends of the long shaft member 1 are supported by bearings, which is different from the above-described embodiments. That is, the through hole 32 is formed in the axial center portion of the base 22 of the spindle motor, and the sleeve member 2 is inserted and fixed to the inner peripheral surface of the through hole 32. The sleeve member 2 is made of a soft metal such as free-cutting brass or phosphor bronze having excellent workability and slidability, and a groove 11 for generating dynamic pressure is formed on the inner radial bearing surface 10 thereof by ball rolling or the like. The dynamic pressure bearing 4 is formed by being formed by plastic working. The base 22 is fixed to a mounting plate 33 by bolts, and the lower opening of the sleeve member 2 is closed by fitting a ball 34. The lower end side of the shaft member 1 is inserted into the sleeve member 2, and the upper end side is HD.
A lid 21f fixed to a mounting plate 33, which is a fixing member of the D spindle motor 21, is penetrated. A bearing case 35 containing the ball bearing 3 is attached to the lid 21f,
The upper end of the shaft member 1 is rotatably supported by the ball bearing 3. Therefore, the ball 34, the sleeve member 2, the base 22, the mounting plate 33, the bearing case 35, and the lid 21f constitute a bearing member 40. The lower radial outer peripheral surface 7 of the shaft member 1 is disposed so as to face the radial bearing surface 10 of the sleeve member 2 with a bearing clearance 8 interposed between the flat lower end surface 1b of the shaft member 1 and the ball 34. The pressure chamber 14 is provided with a slight gap in the axial direction. The arrangement of the motor M in this embodiment is the same as that in the case of the fourth embodiment.

【００３０】この実施形態の場合、このように軸部材１
をハブ２３の外部に延長してその端部を玉軸受３を介し
て回転自在に軸受部材４０に保持させているため、玉軸
受３と動圧軸受４とが軸方向に大きく離れ、軸部材１の
振れ回りを押さえることができるという利点がある。そ
の他の作用効果は上記第４の実施形態の場合と同様であ
る。In the case of this embodiment, the shaft member 1 is thus
Is extended to the outside of the hub 23 and its end is rotatably held by the bearing member 40 via the ball bearing 3, so the ball bearing 3 and the dynamic pressure bearing 4 are largely separated in the axial direction, and the shaft member is There is an advantage that the whirling of 1 can be suppressed. Other functions and effects are similar to those of the above-described fourth embodiment.

【００３１】なお、上記各実施形態においては、動圧軸
受４の動圧発生用の溝１１をスリーブ部材２の内面のラ
ジアル軸受面１０に形成した場合を示したが、これに限
らず、動圧発生用の溝１１を軸部材１のラジアル外周面
７の方に設けても良く、またはラジアル外周面７とラジ
アル軸受面１０との両方に設けても良い。ラジアル外周
面７に動圧発生用の溝１１を設ける場合、軸部材１の材
質としてマルテンサイト系のステンレス鋼を用い、熱処
理により硬さを塑性加工可能なＨＲＣ４０〜５０程度に
保つことにより、ラジアル外周面７に動圧発生用の溝１
１をボール転造により容易に塑性加工することが可能に
なる。また、軸部材１の材質としてステンレス鋼等の焼
入れ可能なものを用いて熱処理等により硬くしておき、
動圧発生用の溝１１をエッチング加工で形成するように
してもよい。動圧発生用の溝１１の溝パターンについて
も、実施形態のものに限定されず、その他の種々の溝パ
ターンを採用することができる。In each of the above-described embodiments, the case where the groove 11 for generating the dynamic pressure of the dynamic pressure bearing 4 is formed on the radial bearing surface 10 of the inner surface of the sleeve member 2 is shown, but the invention is not limited to this. The groove 11 for pressure generation may be provided on the radial outer peripheral surface 7 of the shaft member 1, or may be provided on both the radial outer peripheral surface 7 and the radial bearing surface 10. When the groove 11 for generating dynamic pressure is provided on the radial outer circumferential surface 7, martensitic stainless steel is used as the material of the shaft member 1 and the hardness is maintained at about HRC 40 to 50 which can be plastically worked by heat treatment, whereby the radial Groove 1 for generating dynamic pressure on outer peripheral surface 7
1 can be easily plastically worked by ball rolling. Further, the shaft member 1 is made of a hardenable material such as stainless steel and hardened by heat treatment or the like.
The dynamic pressure generating groove 11 may be formed by etching. The groove pattern of the dynamic pressure generating groove 11 is not limited to that of the embodiment, and various other groove patterns can be adopted.

【００３２】また、上記実施の形態では、玉軸受として
深溝玉軸受を採用しているが、これに限定されず、４点
接触玉軸受等の他の玉軸受を適宜選択することができ、
また、玉軸受の形式、構造、材質及び熱処理等について
も上記実施の形態に限定する必要はなく、適宜変更して
もよい。Further, in the above embodiment, the deep groove ball bearing is adopted as the ball bearing, but the present invention is not limited to this, and another ball bearing such as a four-point contact ball bearing can be appropriately selected.
Further, the type, structure, material, heat treatment and the like of the ball bearing do not have to be limited to the above embodiment, and may be changed as appropriate.

【００３３】[0033]

【発明の効果】以上説明したように、本発明の軸受装置
は、動圧軸受の圧力を利用して玉軸受に予圧を付与する
ものとしたため、従来の軸受装置のような例えば希土類
磁石の反発力または吸引力を利用した高価な予圧付与手
段が不要となり、軸受装置の低コスト化が達成できると
共に、軸受装置の小型化も容易になるという効果が得ら
れる。As described above, in the bearing device of the present invention, the pressure of the dynamic pressure bearing is used to apply the preload to the ball bearing. This eliminates the need for an expensive preload applying means that uses force or suction force, which can reduce the cost of the bearing device and facilitate the downsizing of the bearing device.

【図面の簡単な説明】[Brief description of drawings]

【図１】本発明の軸受装置の第１の実施形態の断面図で
ある。FIG. 1 is a sectional view of a first embodiment of a bearing device of the present invention.

【図２】本発明の軸受装置の第２の実施形態の断面図で
ある。FIG. 2 is a sectional view of a second embodiment of the bearing device of the present invention.

【図３】本発明の軸受装置をスピンドルモータに適用し
た第３の実施形態の断面図である。FIG. 3 is a sectional view of a third embodiment in which the bearing device of the present invention is applied to a spindle motor.

【図４】本発明の軸受装置をスピンドルモータに適用し
た第４の実施形態の断面図である。FIG. 4 is a sectional view of a fourth embodiment in which the bearing device of the present invention is applied to a spindle motor.

【図５】本発明の軸受装置をスピンドルモータに適用し
た第５の実施形態の断面図である。FIG. 5 is a sectional view of a fifth embodiment in which the bearing device of the present invention is applied to a spindle motor.

【図６】従来の軸受装置を用いたスピンドルモータの断
面図である。FIG. 6 is a sectional view of a spindle motor using a conventional bearing device.

【符号の説明】[Explanation of symbols]

１ 軸部材 ２ スリーブ部材 ３ 玉軸受 ４ 動圧軸受 １４ 圧力室 ２０ 軸受装置 ４０ 軸受部材 1 Shaft member 2 Sleeve member 3 Ball bearing 4 Dynamic pressure bearing 14 Pressure chamber 20 Bearing device 40 Bearing member

Claims (1)

【特許請求の範囲】[Claims] 【請求項１】 軸部材と軸受部材とを、軸方向に間隔を
置いて配置した玉軸受と動圧軸受とを介して相対回転自
在に組み立てると共に、前記軸部材の動圧軸受側の端面
と軸受部材との間に圧力室を設け、その圧力室に軸受装
置の作動時に前記動圧軸受から流体を供給して前記玉軸
受に予圧を付与することを特徴とする軸受装置。1. A shaft member and a bearing member are rotatably assembled relative to each other via a ball bearing and a dynamic pressure bearing which are arranged at intervals in the axial direction, and an end face of the shaft member on the dynamic pressure bearing side. A bearing device, wherein a pressure chamber is provided between the bearing member and the pressure chamber, and a fluid is supplied from the dynamic pressure bearing to the pressure chamber when the bearing device is activated to apply a preload to the ball bearing.