本発明は、高回転精度、高速安定性、高耐久性などに優れた特徴を有する動圧型軸受ユニットおよびその製造方法に関する。この動圧型軸受ユニットは、特に高回転精度が要求される光ディスク装置（ＣＤ−ＲＯＭ、ＤＶＤ−ＲＯＭ、ＤＶＤ−ＲＡＭなど）、磁気ディスク装置（ＨＤＤ、ＦＤＤなど）、光磁気ディスク装置（ＭＤ、ＭＯなど）などの情報記憶装置や、レーザビームプリンタなどの情報処理装置のスピンドルモータに使用される軸受として好適なものである。 The present invention relates to a hydrodynamic bearing unit having features excellent in high rotation accuracy, high-speed stability, high durability, and the like, and a manufacturing method thereof. This dynamic pressure type bearing unit is particularly suitable for optical disk devices (CD-ROM, DVD-ROM, DVD-RAM, etc.), magnetic disk devices (HDD, FDD, etc.), magneto-optical disk devices (MD, MO, etc.) that require high rotational accuracy. Etc.) and a bearing used for a spindle motor of an information processing apparatus such as a laser beam printer.
上記各種情報機器のスピンドルモータには、高回転精度の他、高速化、低コスト化、低騒音化などが求められている。これらの要求性能を決定づける構成要素の一つに当該モータのスピンドルを支持する軸受があり、近年では、この種の軸受として、上記要求性能に優れた特性を有する動圧型焼結含油軸受の使用が検討され、あるいは実際に使用されている。 In addition to high rotational accuracy, spindle motors of the various information devices are required to have high speed, low cost, low noise, and the like. One of the components that determine these required performances is a bearing that supports the spindle of the motor. In recent years, the use of a hydrodynamic sintered oil-impregnated bearing having the above-mentioned characteristics excellent in required performance has been used as this type of bearing. Considered or actually used.
動圧型焼結含油軸受は、軸部材の外周面と軸受隙間を介して対向する軸受面を備える焼結金属製の軸受本体に潤滑油や潤滑グリースを含浸させ、軸部材と軸受本体との相対回転時に軸受隙間に動圧油膜を形成して、回転軸を非接触支持するものである。従来、この動圧型焼結含油軸受を使用した軸受ユニットしては、図５に概略図示するように、円筒状のハウジング６'の内周部に厚肉円筒状の上記軸受本体７'を固定し、ハウジング内の空間を潤滑油で満たすと共に、軸受本体７'に回転軸２'を挿入し、ハウジング６'底部の開口部を底板6a'で封口した構造が知られている（例えば、特許文献１）。
ハウジング６'内周部への軸受本体７'の固定方法としては、圧入が一般的である。この圧入作業は、例えば、軸受本体の内径孔に矯正ピンを挿入すると共に、軸受本体の一端面を圧入治具で加圧することにより行うことができるが、上記のように動圧発生用の動圧溝が軸受本体の内周面に設けられる場合には、加圧に伴って軸受本体の内周面が矯正ピンの外周面に食いつくため、動圧溝の一部がつぶれかねない。矯正ピンを使用せずに単に圧入すれば、動圧溝がつぶれることはないが、その場合には圧入時の軸受本体の収縮度合いが軸受精度（軸受本体各部の偏肉、密度の違いなど）やハウジング６'の形状（肉厚の変化など）に影響され、軸受面の円筒度や同軸度などが狂うおそれがある。 As a method of fixing the bearing body 7 'to the inner peripheral portion of the housing 6', press-fitting is generally used. This press-fitting operation can be performed, for example, by inserting a correction pin into the inner diameter hole of the bearing body and pressurizing one end surface of the bearing body with a press-fitting jig. When the pressure groove is provided on the inner peripheral surface of the bearing body, a part of the dynamic pressure groove may be crushed because the inner peripheral surface of the bearing body bites on the outer peripheral surface of the correction pin as the pressure is applied. If you just press-fit without using a straightening pin, the dynamic pressure groove will not be crushed. And the shape of the housing 6 ′ (change in wall thickness, etc.) may cause the cylindricity and coaxiality of the bearing surface to go wrong.
そこで、本発明は、軸受本体をハウジングに固定する際の軸受性能への悪影響（軸受面の変形、精度低下等）を防止することのできる動圧型軸受ユニットおよびその製造方法の提供を目的とする。 SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a hydrodynamic bearing unit capable of preventing adverse effects on the bearing performance when the bearing body is fixed to the housing (deformation of bearing surface, deterioration of accuracy, etc.) and a method for manufacturing the same. .
上記目的を達成するため、本発明は、ハウジングと、ハウジングの内周面に固定され、支持すべき軸部材の外周面と軸受隙間を介して対向する軸受面を有する軸受本体とを備え、軸部材と軸受本体との相対回転時に上記軸受隙間で生じる動圧作用により軸部材を非接触支持する動圧型軸受ユニットにおいて、軸受本体を焼結金属で形成すると共に、ハウジングの内周面に固定される軸受本体の外周面の表面開孔率を１２％以下に調整し、軸受本体の外周面とハウジングの内周面との間のハメアイをすきまばめとし、前記ハメアイすきまの８０％以上の領域に接着剤を行き渡らせることにより、軸受本体の外周面をハウジングの内周面に接着固定した構成を提供する。To achieve the above object, the present invention comprises a housing, and a bearing body having a bearing surface fixed to the inner peripheral surface of the housing and facing the outer peripheral surface of the shaft member to be supported via a bearing gap. In the hydrodynamic bearing unit that supports the shaft member in a non-contact manner by the hydrodynamic action generated in the bearing gap during relative rotation between the member and the bearing body, the bearing body is made of sintered metal and is fixed to the inner peripheral surface of the housing. The surface area of the outer peripheral surface of thebearing body is adjusted to 12% or less,and the hail eye between the outer peripheral surface of thebearing body and the inner peripheral surface of the housing is a clearance fit, and the area is 80% or more of the hail eye clearance. A configuration is provided in which the outer peripheral surfaceof the bearing body is bonded and fixed to the inner peripheral surface of the housingby spreading the adhesive on the inner surface of the housing.
このように、焼結金属からなる軸受本体をハウジングの内周面に接着固定することで、固定する際の軸受性能への悪影響（軸受面の変形、精度低下等）を防止することができる。また、ハウジングの内周面に固定される軸受本体の外周面の表面開孔率を１２％以下に調整することにより、接着剤成分と油とが混じり合うことによる接着力の低下や、接着剤成分を含む油が外周面の表面開孔から軸受本体の内部に入り、さらに軸受面に滲み出すことよる軸受機能への好ましくない影響を回避することができる。 Thus, by adhering and fixing the bearing body made of sintered metal to the inner peripheral surface of the housing, adverse effects on the bearing performance (deformation of the bearing surface, reduction in accuracy, etc.) at the time of fixing can be prevented. Further, by adjusting the surface area ratio of the outer peripheral surface of the bearing body fixed to the inner peripheral surface of the housing to 12% or less, the adhesive force decreases due to the mixture of the adhesive component and the oil, or the adhesive Undesirable influence on the bearing function due to the oil containing the component entering the inside of the bearing body through the surface opening of the outer peripheral surface and further oozing out to the bearing surface can be avoided.
また、軸受本体の外周面とハウジングの内周面との間のハメアイをすきまばめとし、このハメアイすきまで軸受本体の外周面とハウジングの内周面とを接着することにより、接着剤が接合面に均一に薄く広がって局所的に溜まるようなこともないので、接着剤の膨張収縮量のバラツキによる組立精度の低下を最小限に抑えることができる。しかも、接着剤を、上記ハメアイすきまの８０％以上の領域に行き渡らせることにより、実用上十分な接着力が得られる。In addition , the adhesive between the outer peripheral surface of the bearing body and the inner peripheral surface of the housing is a clearance fit,and the adhesive is bondedby bonding the outer peripheral surface of the bearing body and the inner peripheral surface of the housing up to this clearance. Since it does not spread evenly on the surface and accumulate locally, it is possible to minimize a decrease in assembly accuracy due to variations in the amount of expansion and contraction of the adhesive. Moreover, a practically sufficient adhesive force can be obtained by spreading the adhesiveover an area of80% or more of the above-mentioned gap between the eyelashes.
軸部材を軸受本体の内径部に挿入する際には、空気は軸受本体の内周面と軸部材の外周面との間の軸受すきまから逃げることになるが、軸受すきまは数μｍ程度しかないため、空気がハウジングの底部空間に閉じ込められ、軸部材の挿入が難しくなることがある。また、モータ駆動時の発熱等により、閉じ込められた空気が膨張し、軸部材を押し上げて軸受性能を不安定化させるおそれもある。これらの問題は、軸受本体の外周面とハウジングの内周面との間に、軸受本体の軸方向の両端に開口する通気路を設けることによって解消することができる。この場合、通気路の数は一つでも複数でもよく、また通気路は、軸受本体の外周面とハウジングの内周面の何れか一方、または双方に設けることができる。 When the shaft member is inserted into the inner diameter portion of the bearing body, air escapes from the bearing clearance between the inner peripheral surface of the bearing body and the outer peripheral surface of the shaft member, but the bearing clearance is only a few μm. Therefore, air is trapped in the bottom space of the housing, and insertion of the shaft member may be difficult. In addition, the trapped air expands due to heat generated when the motor is driven, and the shaft member may be pushed up to destabilize the bearing performance. These problems can be solved by providing air passages that are open at both ends in the axial direction of the bearing body between the outer circumferential surface of the bearing body and the inner circumferential surface of the housing. In this case, the number of air passages may be one or more, and the air passages may be provided on either or both of the outer peripheral surface of the bearing body and the inner peripheral surface of the housing.
また、本発明は、上記目的を達成するため、ハウジングと、ハウジングの内周面に固定され、支持すべき軸部材の外周面と軸受隙間を介して対向する軸受面を有する軸受本体とを備え、軸部材と軸受本体との相対回転時に上記軸受隙間で生じる動圧作用により軸部材を非接触支持する動圧型軸受ユニットを製造する方法であって、軸受本体の外周面とハウジングの内周面との間のハメアイをすきまばめとし、ハメアイすきまに接着剤を供給すると共に、ハメアイすきま内の接着剤に、前記ハメアイすきまの毛細管力よりも小さな負圧による吸引力を作用させて、接着剤をハメアイすきまの８０％以上の領域に行き渡らせ、これにより、軸受本体の外周面をハウジングの内周面に接着固定する構成を提供する。In order to achieve the above object, the present invention includes a housing, and a bearing main body having a bearing surface fixed to the inner peripheral surface of the housing and facing the outer peripheral surface of the shaft member to be supported via a bearing gap. A method of manufacturing a hydrodynamic bearing unit that supports a shaft member in a non-contact manner by a hydrodynamic action generated in the bearing gap during relative rotation between the shaft member and the bearing body, the outer circumferential surface of the bearing body and the inner circumferential surface of the housing The adhesive is applied to the adhesive with a negative pressuresmaller than the capillary force of the HAMEAI clearance, and the adhesive is supplied to the HAMEAI clearance. Is distributedover an area of80% or more of the clearance of the hail eye, whereby the outer peripheral surface of the bearing body is bonded and fixed to the inner peripheral surface of the housing.
本発明によれば、焼結金属からなる軸受本体をハウジングの内周面に接着固定するので、固定する際の軸受性能への悪影響（軸受面の変形、精度低下等）を防止することができる。また、ハウジングの内周面に固定される軸受本体の外周面の表面開孔率を１２％以下に調整しているので、接着剤成分と油とが混じり合うことによる接着力の低下や、接着剤成分を含む油が外周面の表面開孔から軸受本体の内部に入り、さらに軸受面に滲み出すことよる軸受機能への好ましくない影響を回避することができる。また、軸受本体の外周面とハウジングの内周面との間のハメアイをすきまばめとし、このハメアイすきまで軸受本体の外周面とハウジングの内周面とを接着することにより、接着剤が接合面に均一に薄く広がって局所的に溜まるようなこともないので、接着剤の膨張収縮量のバラツキによる組立精度の低下を最小限に抑えることができる。しかも、接着剤を、上記ハメアイすきまの８０％以上の領域に行き渡らせることにより、実用上十分な接着力が得られる。According to the present invention, since the bearing main body made of sintered metal is bonded and fixed to the inner peripheral surface of the housing, it is possible to prevent adverse effects on the bearing performance (deformation of the bearing surface, decrease in accuracy, etc.) during fixing. . In addition, since the surface area ratio of the outer peripheral surface of the bearing body fixed to the inner peripheral surface of the housing is adjusted to 12% or less, the adhesive force decreases due to the mixing of the adhesive component and oil, It is possible to avoid an unfavorable influence on the bearing function due to the oil containing the agent component entering the inside of the bearing body from the surface opening of the outer peripheral surface and further oozing out to the bearing surface.In addition, the adhesive between the outer peripheral surface of the bearing body and the inner peripheral surface of the housing is a clearance fit, and the adhesive is bonded by bonding the outer peripheral surface of the bearing body and the inner peripheral surface of the housing up to this clearance. Since it does not spread evenly on the surface and accumulate locally, it is possible to minimize a decrease in assembly accuracy due to variations in the amount of expansion and contraction of the adhesive. Moreover, a practically sufficient adhesive force can be obtained by spreading the adhesive over an area of 80% or more of the above-mentioned gap between the eyelashes.
また、軸受本体の外周面とハウジングの内周面との間のハメアイをすきまばめとし、ハメアイすきまに接着剤を供給すると共に、ハメアイすきま内の接着剤に負圧による吸引力を作用させて、接着剤をハメアイすきまの８０％以上の領域に行き渡らせることにより、強固な接着固定力を得ることができる。しかも、負圧による吸引力を、ハメアイすきまの毛細管力よりも小さく設定しているので、ハメアイすきまに供給された接着剤が吸引力の吸引方向に過剰に流動する事態が回避される。そのため、接着剤を、ハメアイすきまの８０％以上の領域に薄く均一に広げて、強力な接着力を得ることができる。In addition, a gap fit between the outer peripheral surface of the bearing body and the inner peripheral surface of the housing is used as a clearance fit, and an adhesive is supplied to the gap and a suction force due to negative pressure is applied to the adhesive in the gap. A strong adhesive fixing force can be obtained by spreading the adhesiveover an area of80% or more of the clearance of the eye eye.In addition, since the suction force due to the negative pressure is set to be smaller than the capillary force of the hameai gap, a situation in which the adhesive supplied to the hameai gap excessively flows in the suction direction of the suction force is avoided. Therefore, it is possible to obtain a strong adhesive force by spreading the adhesive thinly and evenly in an area of 80% or more of the hameai gap.
以下、本発明の実施形態を図１乃至図５に基づいて説明する。 Hereinafter, embodiments of the present invention will be described with reference to FIGS.
図１は、本発明にかかる動圧型軸受ユニット１を備える情報機器用スピンドルモータの断面図で、一例としてＬＢＰ（レーザビームプリンタ）のポリゴンスキャナモータを示している。このスピンドルモータは、軸部材２を回転自在に支持する軸受ユニット１と、軸部材２に取付けられ、図示しないポリゴンミラーを保持するロータハブ３と、軸方向のギャップを介して対向させたモータステータ４およびモータロータ５とを有する。ステータ４は、軸受ユニット１を保持するケーシング９に取付けられ、ロータ５はロータハブ３に取付けられている。ステータ４に通電すると、ステータ４とロータ５との間の励磁力でロータ５が回転し、ロータハブ３および軸部材２が回転する。 FIG. 1 is a cross-sectional view of a spindle motor for information equipment provided with a dynamic pressure type bearing unit 1 according to the present invention. As an example, a polygon scanner motor of an LBP (laser beam printer) is shown. The spindle motor includes a bearing unit 1 that rotatably supports a shaft member 2, a rotor hub 3 that is attached to the shaft member 2 and holds a polygon mirror (not shown), and is opposed to the motor stator 4 via an axial gap. And a motor rotor 5. The stator 4 is attached to a casing 9 that holds the bearing unit 1, and the rotor 5 is attached to the rotor hub 3. When the stator 4 is energized, the rotor 5 is rotated by the exciting force between the stator 4 and the rotor 5, and the rotor hub 3 and the shaft member 2 are rotated.
軸受ユニット１は、軸部材２と、有底円筒状のハウジング６と、ハウジング６の内周面に固定された円筒状の軸受本体７と、軸受本体７の一端側（ハウジング６の開口側をいう）を密封するシールワッシャ等のシール部材８と、軸部材２をそれぞれラジアル方向およびスラスト方向で支持するラジアル軸受部10およびスラスト軸受部11とを有する。 The bearing unit 1 includes a shaft member 2, a bottomed cylindrical housing 6, a cylindrical bearing body 7 fixed to the inner peripheral surface of the housing 6, and one end side of the bearing body 7 (the opening side of the housing 6 is A seal member 8 such as a seal washer, and a radial bearing portion 10 and a thrust bearing portion 11 that support the shaft member 2 in the radial direction and the thrust direction, respectively.
軸受本体７の内周面には動圧溝を有するラジアル軸受面7aが形成される。図２（Ａ）に示すように、本実施形態では軸受本体７の内周面の複数箇所（例えば二箇所）にラジアル軸受面7aを設けた場合を例示する。但し、ラジアル軸受面7aの数は任意であり、軸受の使用条件等に応じて一つあるいは三つ以上とすることもできる。軸部材２と軸受本体７の相対回転時（本実施形態では軸部材２の回転時）には、ラジアル軸受面7aと軸部材２の外周面との間の軸受隙間に動圧が発生し、軸部材２を非接触支持するラジアル軸受部10が構成される。 A radial bearing surface 7 a having a dynamic pressure groove is formed on the inner peripheral surface of the bearing body 7. As shown in FIG. 2A, in this embodiment, a case where radial bearing surfaces 7a are provided at a plurality of locations (for example, two locations) on the inner peripheral surface of the bearing body 7 is illustrated. However, the number of radial bearing surfaces 7a is arbitrary, and may be one or three or more according to the use conditions of the bearings. During relative rotation of the shaft member 2 and the bearing body 7 (in the present embodiment, when the shaft member 2 is rotated), dynamic pressure is generated in the bearing gap between the radial bearing surface 7a and the outer peripheral surface of the shaft member 2, A radial bearing portion 10 that supports the shaft member 2 in a non-contact manner is configured.
ラジアル軸受面7aの動圧溝形状は、各動圧溝が軸方向に対して傾斜している限り任意に選択することができ、公知のへリングボーン型やスパイラル型等が使用可能である。図２（Ａ）はへリングボーン型のラジアル軸受面7aを例示するもので、このラジアル軸受面7aは、一方に傾斜する動圧溝15が形成された第１の溝領域m1と、第１の溝領域m1から軸方向に離隔し、他方に傾斜する動圧溝15が配列された第２の溝領域m2と、２つの溝領域間m1、m2間に位置する環状の平滑部ｎとを備え、２つの溝領域m1、m2の動圧溝15は平滑部ｎで区画されて非連続になっている。平滑部ｎと動圧溝15間の背の部分16とは同一レベルにある。この種の非連続型の動圧溝15は、連続型、すなわち平滑部ｎを省略し、動圧溝15を両溝領域m1、m2間で互いに連続するＶ字状に形成した場合に比べ、平滑部ｎを中心として油が集められるために油膜圧力が高く、また溝のない平滑部ｎを有するので軸受剛性が高いという利点を有する。 The dynamic pressure groove shape of the radial bearing surface 7a can be arbitrarily selected as long as each dynamic pressure groove is inclined with respect to the axial direction, and a known herringbone type, spiral type, or the like can be used. FIG. 2A illustrates a herringbone radial bearing surface 7a. The radial bearing surface 7a includes a first groove region m1 in which a dynamic pressure groove 15 inclined on one side is formed, and a first groove region 1a. A second groove region m2 in which a dynamic pressure groove 15 that is axially separated from the other groove region m1 and inclined to the other is arranged, and an annular smooth portion n positioned between the two groove regions m1 and m2. In addition, the dynamic pressure grooves 15 in the two groove regions m1 and m2 are partitioned by the smooth portion n and are discontinuous. The back portion 16 between the smooth portion n and the dynamic pressure groove 15 is at the same level. This type of non-continuous type dynamic pressure groove 15 is continuous type, that is, the case where the smoothing portion n is omitted and the dynamic pressure groove 15 is formed in a V-shape that is continuous between both groove regions m1 and m2. Since oil is collected around the smooth portion n, the oil film pressure is high, and since the smooth portion n without a groove is provided, the bearing rigidity is high.
軸受本体７は、銅や真鍮などの軟質金属、あるいは焼結金属によって形成され、本実施形態では一例として焼結金属からなる軸受本体７を例示している。焼結金属を用いた場合、ラジアル軸受面7aの動圧溝は、圧縮成形、すなわちコアロッドの外周面にラジアル軸受面7aの動圧溝形状（図２（Ａ）参照）に対応した凹凸形状の溝型を形成し、コアロッドの外周に焼結金属を供給して焼結金属を圧迫し、焼結金属の内周部に溝型形状に対応した動圧溝を転写することによって、低コストにかつ高精度に成形することができる。なお、焼結金属の脱型は、圧迫力を解除することによる素材のスプリングバックを利用して簡単に行える。脱型後の軸受本体７に潤滑油や潤滑グリースを含浸して油を保有させることにより、動圧型焼結含油軸受が構成される。 The bearing body 7 is made of a soft metal such as copper or brass, or a sintered metal. In the present embodiment, the bearing body 7 made of a sintered metal is illustrated as an example. When sintered metal is used, the dynamic pressure groove on the radial bearing surface 7a is formed by compression molding, that is, an uneven shape corresponding to the dynamic pressure groove shape of the radial bearing surface 7a (see FIG. 2A) on the outer peripheral surface of the core rod. By forming a groove mold, supplying sintered metal to the outer periphery of the core rod, pressing the sintered metal, and transferring the dynamic pressure groove corresponding to the groove mold shape to the inner periphery of the sintered metal, the cost is reduced. And it can shape | mold with high precision. It should be noted that the demolding of the sintered metal can be easily performed by utilizing the spring back of the material by releasing the pressing force. A hydrodynamic sintered oil-impregnated bearing is constructed by impregnating the bearing body 7 after demolding with lubricating oil or lubricating grease to retain the oil.
図２（Ａ）（Ｂ）に示すように、軸受本体７の外周面には、軸受本体７の内径部に軸部材２を挿入する際の空気抜きとなる一または複数（本実施形態では一つ）の通気溝17（通気路）が軸方向に沿って形成される。また、軸受本体７の一方の端面、具体的にはハウジング６の底部6aと対向する端面7bには環状溝18が設けられる。この環状溝18は、例えば軸受本体７をハウジング６に挿入する際の挿入方向を判別する識別マークとして機能させることができる。環状溝18と通気溝17との間には、半径方向の連通溝19が設けられており、この連通溝19を介して環状溝18と通気溝17とがつながっている。 2A and 2B, the outer peripheral surface of the bearing body 7 is provided with one or a plurality (one in this embodiment) that serve as an air vent when the shaft member 2 is inserted into the inner diameter portion of the bearing body 7. ) Is formed along the axial direction. An annular groove 18 is provided on one end surface of the bearing body 7, specifically, on the end surface 7 b facing the bottom portion 6 a of the housing 6. The annular groove 18 can function as an identification mark for determining the insertion direction when the bearing body 7 is inserted into the housing 6, for example. A radial communication groove 19 is provided between the annular groove 18 and the ventilation groove 17, and the annular groove 18 and the ventilation groove 17 are connected via the communication groove 19.
ハウジング６は、図５に示す円筒状のハウジング６'と底板6a'とを一体化した有底筒型のいわゆる袋型ハウジングである。ハウジング６の底部6a（軸受本体７の端面との対向部）には、樹脂等の低摩擦材料で形成された板状のスラスト受け20が装着され、このスラスト受け20に軸部材２の球面状の軸端を接触させて、軸部材２をスラスト方向でピボット支持するスラスト軸受部11が構成される。ハウジング６の内周面の底付近、具体的には当該内周面とハウジング底部6aとの境界部には、ハウジング内径側に突出する段部21が設けられる。この段部21は軸受本体７の端面7bと係合してその軸方向の位置決めを行うもので、その位置決めは、軸受本体７の端面7bとハウジング６の底部6a（具体的にはスラスト受け板20）との間に軸方向の空間22（底部空間）が形成されるように行われる。段部21は図示のようにハウジング６と一体に形成する他、別部材で構成してもよい。軸受本体７の端面7bにおける段部21との接触領域は、上記環状溝18よりも外径側にあり、従って上記底部空間22は環状溝18、連通溝19を介して通気溝17に連通している。 The housing 6 is a so-called bag-shaped housing having a bottomed cylindrical shape in which a cylindrical housing 6 ′ and a bottom plate 6a ′ shown in FIG. 5 are integrated. A plate-like thrust receiver 20 made of a low friction material such as resin is attached to the bottom 6a of the housing 6 (opposite the end face of the bearing body 7), and the spherical surface of the shaft member 2 is attached to the thrust receiver 20. A thrust bearing portion 11 that pivotally supports the shaft member 2 in the thrust direction is configured by contacting the shaft ends of the shaft member 2. In the vicinity of the bottom of the inner peripheral surface of the housing 6, specifically, at the boundary between the inner peripheral surface and the housing bottom 6 a, a step portion 21 that protrudes toward the housing inner diameter side is provided. The step portion 21 is engaged with the end surface 7b of the bearing body 7 to perform axial positioning thereof. The positioning is performed by the end surface 7b of the bearing body 7 and the bottom portion 6a of the housing 6 (specifically, a thrust receiving plate). 20), an axial space 22 (bottom space) is formed. The step portion 21 is formed integrally with the housing 6 as shown in the figure, or may be constituted by another member. The contact area of the end surface 7b of the bearing body 7 with the step portion 21 is on the outer diameter side with respect to the annular groove 18, so that the bottom space 22 communicates with the ventilation groove 17 via the annular groove 18 and the communication groove 19. ing.
上記軸受ユニットの組立に際しては、先ず軸受本体７をハウジング６の内周面に挿入し、軸受本体７の端面7bを段部21に係合させて軸受本体７を軸方向で位置決めする。次いでこのアッセンブリを接着工程に移送し、軸受本体７をハウジング６の内周面に接着固定する。この接着工程は、従来のようにハウジング６が底部を開放した円筒型である場合、図４に示す治具25'を用い、ハウジング６の底部開口側から接着剤を供給することで行うことができる。ところが、上記のように有底円筒状のハウジング６を使用する場合には、底部6aが存在するためにこの種の治具25'を用いることはできない。そこで、本発明では、図３に示す固定装置を用いて接着工程を行うこととした。 In assembling the bearing unit, first, the bearing body 7 is inserted into the inner peripheral surface of the housing 6, and the end surface 7 b of the bearing body 7 is engaged with the step portion 21 to position the bearing body 7 in the axial direction. Next, this assembly is transferred to the bonding step, and the bearing body 7 is bonded and fixed to the inner peripheral surface of the housing 6. When the housing 6 has a cylindrical shape with the bottom opened as in the prior art, this bonding step can be performed by supplying an adhesive from the bottom opening side of the housing 6 using a jig 25 'shown in FIG. it can. However, when the bottomed cylindrical housing 6 is used as described above, this kind of jig 25 'cannot be used because the bottom portion 6a exists. Therefore, in the present invention, the bonding process is performed using the fixing device shown in FIG.
この固定装置は、接着治具25と治具25に接続した吸気源（図示せず）とで構成される。治具25は、ハウジング６の開口側端部に被せられる有底筒状の治具本体26と、軸受本体７の内周部に挿入されるピン部27とで構成される。治具25は、治具本体26の底部26ａをハウジング６の開口端に係合させて軸方向で位置決めされ、この時、ピン部27の先端は底部空間22に達している。ピン部27には、吸気路28が形成されており、その一端は上記底部空間22に開口し、他端は吸気源側に接続されている。治具25は、軸受本体７の内周面と、この面に対して所定の組立精度が要求される面、例えばハウジング６の外周面との間の精度（同軸度等）が規格内に納まるよう所定精度で形成される。例えば軸受本体７の内周面とピン部27の外周面とは２μｍ以内のすきまばめになっており、これによってピン部27に対する軸受本体７の倒れが防止され、両者間での同軸度等の精度が保持される。 The fixing device includes an adhesive jig 25 and an intake source (not shown) connected to the jig 25. The jig 25 includes a bottomed cylindrical jig main body 26 that covers the opening-side end portion of the housing 6 and a pin portion 27 that is inserted into the inner peripheral portion of the bearing main body 7. The jig 25 is positioned in the axial direction by engaging the bottom portion 26 a of the jig body 26 with the opening end of the housing 6. At this time, the tip of the pin portion 27 reaches the bottom space 22. The pin portion 27 is formed with an intake passage 28, one end of which opens into the bottom space 22 and the other end is connected to the intake source side. The jig 25 has an accuracy (coaxiality, etc.) between the inner peripheral surface of the bearing body 7 and a surface that requires a predetermined assembly accuracy with respect to this surface, for example, the outer peripheral surface of the housing 6, within the standard. It is formed with a predetermined accuracy. For example, the inner peripheral surface of the bearing body 7 and the outer peripheral surface of the pin portion 27 have a clearance fit of 2 μm or less, which prevents the bearing body 7 from falling over the pin portion 27, the degree of coaxiality between the two, etc. The accuracy of is maintained.
吸気源を起動し、ハウジング６の底部6aと軸受本体７の端面7bとの間の底部空間22を吸引（真空吸引）すると、底部空間22が負圧となり、軸受本体７がハウジング６の底部6a側に引き寄せられて段部21に押付けられる。上記のように軸受本体７は僅かなすきまを介してピン部27に嵌合しており、かつ吸引により軸受本体７が段部21に押付けられるため、軸受本体７はハウジング６に対して半径方向および軸方向で高精度に位置決めされる。 When the intake air source is activated and the bottom space 22 between the bottom 6a of the housing 6 and the end surface 7b of the bearing body 7 is sucked (vacuum suction), the bottom space 22 becomes negative pressure, and the bearing body 7 becomes the bottom 6a of the housing 6. To the side and pressed against the stepped portion 21. As described above, the bearing body 7 is fitted to the pin portion 27 through a slight gap, and the bearing body 7 is pressed against the stepped portion 21 by suction. And it is positioned with high accuracy in the axial direction.
この状態で、ハウジング６の開口側から軸受本体７の外周面とハウジング６の内周面との間、具体的には軸受本体７のハウジング開口側の外径側チャンファ部7cにディスペンサ29から所定量の接着剤を注入する。注入された接着剤は毛細管現象で接合面に広がるが、上記のように底部空間22が負圧となるため、接着剤はハウジング６の底部6a側に吸引され、接合面の全体に速やかに行き渡る。この時、接着剤がスムーズに広がるよう軸受本体７の外周面とハウジング６の内周面との間のハメアイは、すきまばめとする。このハメアイすきまは機械設計で常用される範囲を基本とするが、ハメアイすきまが小さすぎると接着剤がスムーズに広がりにくく、また、大きすぎると軸受本体７とハウジング６との間の半径方向精度に悪影響を及ぼすので、概ね５μｍ以上で５０μｍ以下、望ましくは１０μｍ以上で３０μｍ以下のハメアイすきまとするのがよい。 In this state, the dispenser 29 is disposed from the opening side of the housing 6 between the outer peripheral surface of the bearing body 7 and the inner peripheral surface of the housing 6, specifically, the outer diameter side chamfer portion 7 c on the housing opening side of the bearing body 7. Inject a fixed amount of adhesive. The injected adhesive spreads on the joint surface by capillary action, but since the bottom space 22 becomes negative pressure as described above, the adhesive is sucked to the bottom 6a side of the housing 6 and quickly spreads over the entire joint surface. . At this time, the gap between the outer peripheral surface of the bearing body 7 and the inner peripheral surface of the housing 6 is a clearance fit so that the adhesive spreads smoothly. This clearance is based on the range that is commonly used in mechanical design. However, if the clearance is too small, the adhesive will not spread smoothly. Since it has an adverse effect, it is preferable that the clearance is about 5 μm or more and 50 μm or less, preferably 10 μm or more and 30 μm or less.
以上の構成から、上記ハメアイすきま（接着隙間）のほぼ全領域、具体的には８０％以上の領域に接着剤を行き渡らせることができ、その結果、ハメアイすきまで軸受本体７とハウジング６とが強固に接着固定される。接着剤はハメアイすきまのほぼ全面に薄く均一に広がるため、強力な接着力が確保され、かつ局所的に接着剤が溜まるようなこともない。従って、軸受ユニットを治具25から取出しても、あるいは周囲温度の変化により、接着剤が軸受本体７やハウジング６に対して相対的に大きく膨張収縮するようなことあっても組立精度が損なわれることはない。 With the above configuration, the adhesive can be spread over almost the entire area of the above-mentioned gap (gap gap), specifically 80% or more. As a result, the bearing main body 7 and the housing 6 are moved to the gap. It is firmly bonded and fixed. Since the adhesive spreads thinly and uniformly over almost the entire surface of the gap between the eyelashes, a strong adhesive force is ensured and the adhesive does not accumulate locally. Therefore, even if the bearing unit is taken out from the jig 25, or the adhesive expands and contracts relatively with respect to the bearing body 7 and the housing 6 due to changes in the ambient temperature, the assembly accuracy is impaired. There is nothing.
上記接着工程においては、吸気源の吸引力は、ハメアイすきまの毛細管力よりも小さく設定するのがよく、これより接着剤が軸受本体７のハウジング底部側の外径チャンファ部7dに達した後、当該チャンファ部7dに入り込んだり、通気溝17に入り込んだりする事態を防止することができる。また、接着剤の注入は通気溝17を避けて行われる。接着剤は一個所のみで注入してもよいが、より均一な接着層を形成するために軸受本体７の開口側端面の円周方向複数箇所で注入するのが望ましい。接着は、軸受本体７の外周面に付着した油をウェスなどで拭き取るか、あるいは遠心分離機などで除去した上で行うのがよい。 In the above bonding step, the suction force of the intake source is preferably set smaller than the capillary force of the gap between the gaps, and after the adhesive reaches the outer diameter chamfer portion 7d on the housing bottom side of the bearing body 7, It is possible to prevent a situation where the chamfer part 7d enters or the ventilation groove 17 enters. The adhesive is injected while avoiding the ventilation groove 17. The adhesive may be injected only at one location, but it is desirable to inject it at a plurality of locations in the circumferential direction on the opening side end face of the bearing body 7 in order to form a more uniform adhesive layer. Adhesion is preferably performed after wiping off the oil adhering to the outer peripheral surface of the bearing body 7 with a waste cloth or removing it with a centrifuge.
ところで、上記のように接着する場合、接着剤成分と油とが混じり合うため、接着力が低下したり、あるいは接着剤成分を含む油が接合部から軸受内部に侵入し、さらにこれが軸受面に滲出して軸受機能上好ましくない影響を与えるおそれもある。これを回避するには、軸受本体７の外周面のうち、ハウジング６の内周面に接着される部分（本実施形態では外周面の全体）の表面開孔率を１２％以下、望ましくは８％以下にするとよい。この程度の表面開孔率であれば、塗布した接着剤のほとんどが接合面に残り、軸受内部に侵入することがなくなる。したがって、接着力が落ちることはなく、また、潤滑に対して悪影響を及ぼすこともない。 By the way, when adhering as described above, the adhesive component and the oil are mixed, so that the adhesive force is reduced, or the oil containing the adhesive component penetrates into the bearing from the joint portion, and this further enters the bearing surface. There is a possibility that it may exude and adversely affect the bearing function. In order to avoid this, the surface open area ratio of the outer peripheral surface of the bearing body 7 bonded to the inner peripheral surface of the housing 6 (in this embodiment, the entire outer peripheral surface) is 12% or less, preferably 8 % Or less. With this degree of surface opening ratio, most of the applied adhesive remains on the joint surface and does not enter the bearing. Therefore, the adhesive force does not drop and does not adversely affect the lubrication.
接着剤としては、嫌気性接着剤や紫外線硬化型接着剤、あるいは双方の性質を有する接着剤が使用される。これらは、油面での接着力に優れており、軸受本体７やハウジング６の素材としてよく使用される銅系材料に対する反応性もよい。また、固着スピードが速いため、軸受本体７やハウジング６を治具25で位置決め保持する時間を短くすることができる。さらには、何れも一液性で、例えばエポキシ接着剤のように二液を混合する必要がなく、作業性に優れる。特に紫外線硬化型接着剤の場合は、仮に軸受外径部のチャンファなどに接着剤が付着して残っても紫外線を照射することにより、そこで固めてしまうことができる。 As the adhesive, an anaerobic adhesive, an ultraviolet curable adhesive, or an adhesive having both properties is used. These are excellent in adhesive strength on the oil surface, and also have good reactivity with copper-based materials that are often used as materials for the bearing body 7 and the housing 6. Further, since the fixing speed is fast, the time for positioning and holding the bearing body 7 and the housing 6 with the jig 25 can be shortened. Furthermore, both are one-component, and it is not necessary to mix two components like an epoxy adhesive, for example, and it is excellent in workability | operativity. In particular, in the case of an ultraviolet curable adhesive, even if the adhesive remains attached to a chamfer or the like of the outer diameter portion of the bearing, it can be hardened by irradiating with ultraviolet rays.
なお、以上の説明では、底部空間22と通気溝17とを環状溝18や半径方向の連通溝19を介して連通させる場合を例示しているが、本発明の目的を達成するためには底部空間22と通気溝17とが連通状態にあって、相互に通気可能であれば十分である。従って、環状溝18や連通溝19の形状、構成等は図示のものに限定されず、これらを他の適当な通気手段（溝、孔、凹部等）に置換することもできる。 In the above description, the case where the bottom space 22 and the ventilation groove 17 are communicated with each other via the annular groove 18 and the communication groove 19 in the radial direction is illustrated. However, in order to achieve the object of the present invention, It is sufficient if the space 22 and the ventilation groove 17 are in communication with each other so that they can vent each other. Accordingly, the shape, configuration, and the like of the annular groove 18 and the communication groove 19 are not limited to those shown in the drawings, and these can be replaced with other appropriate ventilation means (grooves, holes, recesses, etc.).
１ 動圧型軸受ユニット
２ 軸部材
６ ハウジング
７ 軸受本体
7a 軸受面
DESCRIPTION OF SYMBOLS 1 Dynamic pressure type bearing unit 2 Shaft member 6 Housing 7 Bearing body
7a Bearing surface
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| JP2004220815AJP3686665B2 (en) | 2004-07-28 | 2004-07-28 | Hydrodynamic bearing unit and method for manufacturing the same |
| Application Number | Priority Date | Filing Date | Title |
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| JP2004220815AJP3686665B2 (en) | 2004-07-28 | 2004-07-28 | Hydrodynamic bearing unit and method for manufacturing the same |
| Application Number | Title | Priority Date | Filing Date |
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| JP13451299ADivisionJP3921007B2 (en) | 1999-05-14 | 1999-05-14 | Hydrodynamic bearing unit and manufacturing method thereof |
| Publication Number | Publication Date |
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| JP2004316926A JP2004316926A (en) | 2004-11-11 |
| JP3686665B2true JP3686665B2 (en) | 2005-08-24 |
| Application Number | Title | Priority Date | Filing Date |
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| JP2004220815AExpired - LifetimeJP3686665B2 (en) | 2004-07-28 | 2004-07-28 | Hydrodynamic bearing unit and method for manufacturing the same |
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| JP (1) | JP3686665B2 (en) |
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