JP6625332B2 - Housing for fluid dynamic bearing device - Google Patents

Housing for fluid dynamic bearing device Download PDF

Info

Publication number
JP6625332B2
JP6625332B2 JP2015053304A JP2015053304A JP6625332B2 JP 6625332 B2 JP6625332 B2 JP 6625332B2 JP 2015053304 A JP2015053304 A JP 2015053304A JP 2015053304 A JP2015053304 A JP 2015053304A JP 6625332 B2 JP6625332 B2 JP 6625332B2
Authority
JP
Japan
Prior art keywords
housing
gate
bearing
shaft member
end surface
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
JP2015053304A
Other languages
Japanese (ja)
Other versions
JP2016173136A (en
Inventor
柴原　克夫
克夫 柴原
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NTN Corp
Original Assignee
NTN Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by NTN Corp filed Critical NTN Corp
Priority to JP2015053304A priority Critical patent/JP6625332B2/en
Priority to PCT/JP2016/056958 priority patent/WO2016147928A1/en
Publication of JP2016173136A publication Critical patent/JP2016173136A/en
Application granted granted Critical
Publication of JP6625332B2 publication Critical patent/JP6625332B2/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Landscapes

  • Sliding-Contact Bearings (AREA)
  • Mounting Of Bearings Or Others (AREA)
  • Moulds For Moulding Plastics Or The Like (AREA)
  • Injection Moulding Of Plastics Or The Like (AREA)
  • Connection Of Motors, Electrical Generators, Mechanical Devices, And The Like (AREA)

Description

本発明は、流体動圧軸受装置に用いられる樹脂製のハウジングに関する。   The present invention relates to a resin housing used for a fluid dynamic bearing device.

流体動圧軸受装置は、軸部材の外周面と軸受部材の内周面との間のラジアル軸受隙間の流体膜（例えば油膜）に生じる圧力により、軸部材を相対回転自在に非接触支持するものである。流体動圧軸受装置は、その高回転精度および静粛性から、情報機器（例えば、ＨＤＤの磁気ディスク駆動装置等）のスピンドルモータ、レーザビームプリンタのポリゴンスキャナモータ、プロジェクタのカラーホイール、あるいは電気機器の冷却ファンモータなどの小型モータ用として好適に使用される。   The fluid dynamic bearing device is configured to support the shaft member in a non-contact manner so as to be relatively rotatable by a pressure generated in a fluid film (for example, an oil film) in a radial bearing gap between an outer peripheral surface of the shaft member and an inner peripheral surface of the bearing member. It is. Fluid dynamic bearings are used for spindle motors of information equipment (for example, magnetic disk drives of HDDs), polygon scanner motors of laser beam printers, color wheels of projectors, or of electric equipment because of their high rotational accuracy and quietness. It is suitably used for small motors such as cooling fan motors.

流体動圧軸受装置は、例えば、軸部材と、内周に軸部材が挿入された軸受スリーブと、内周面に軸受スリーブが固定された有底筒状のハウジングとを備えた構成を成す。近年、流体動圧軸受装置にはさらなる軽量化及び低コスト化が要求されており、この要求に応えるために有底筒状のハウジングを樹脂で一体に射出成形することがある。例えば下記の特許文献１には、図１５に示すように、成形金型に設けられたランナ１１０ａから、ゲート１１０ｂを介してキャビティ内に溶融樹脂Ｐを射出することで、有底筒状のハウジング１０７を成形する方法が示されている。この場合、型開き前の状態では、同図に示すようにランナ１１０ａ内で固化した樹脂（ランナ樹脂部）と成形品（ハウジング１０７）とが、ゲート１１０ｂ内で固化した樹脂（ゲート樹脂部）を介してつながっているが、型開きを行うことにより、ゲート樹脂部が引きちぎられて、ランナ樹脂部とハウジング１０７とが分離される。   The fluid dynamic bearing device has, for example, a configuration including a shaft member, a bearing sleeve in which the shaft member is inserted in the inner periphery, and a bottomed cylindrical housing in which the bearing sleeve is fixed to the inner peripheral surface. In recent years, further reduction in weight and cost has been demanded for fluid dynamic bearing devices, and in order to meet this demand, a bottomed cylindrical housing may be integrally injection-molded with resin. For example, in Patent Document 1 below, as shown in FIG. 15, a molten resin P is injected into a cavity from a runner 110a provided in a molding die via a gate 110b to form a bottomed cylindrical housing. A method for forming 107 is shown. In this case, before the mold is opened, the resin (the runner resin portion) solidified in the runner 110a and the molded product (the housing 107) are solidified in the gate 110b (the gate resin portion) as shown in FIG. However, by opening the mold, the gate resin portion is torn off, and the runner resin portion and the housing 107 are separated from each other.

このように、ゲート樹脂部を引きちぎることで、その分断面には、充填材や樹脂片からなる鋭利な凹凸が形成される。このような分断面を有するハウジングを流体動圧軸受装置に組み込むと、分断面から脱落した充填材や樹脂片等が、ハウジングの内部に満たされた潤滑油にコンタミとして混入する恐れがある。   In this manner, by tearing off the gate resin portion, sharp irregularities made of a filler or a resin piece are formed on the corresponding cross section. When a housing having such a divided section is incorporated into a fluid dynamic bearing device, there is a possibility that fillers, resin pieces, and the like that have fallen off from the divided section may be mixed as contaminants into lubricating oil filled in the housing.

下記の特許文献１では、成形品（ハウジング）に残ったゲート樹脂部の分断面（ゲート跡）に治具を押し付けて平滑化することにより、コンタミの発生の抑制を図っている。   In the following Patent Document 1, the occurrence of contamination is suppressed by pressing a jig against a cross section (gate trace) of a gate resin portion remaining on a molded product (housing) and smoothing the jig.

特許第４８０８４５７号公報Japanese Patent No. 4808457

しかし、上記のようにハウジングのゲート跡に治具を押し付ける工程を設けると、工数増によりハウジングの製造コストが増加する。また、治具を押し付けてゲート跡を平滑化したとしても、充填材や樹脂片の脱落を確実に防止できるとは言えず、コンタミの発生の懸念は解消しきれない。   However, when the step of pressing the jig against the gate mark of the housing is provided as described above, the manufacturing cost of the housing increases due to an increase in man-hours. Further, even if the jig is pressed to smooth the gate trace, it cannot be said that the filler or the resin piece can be reliably prevented from falling off, and the concern of the occurrence of contamination cannot be completely solved.

また、型開きによりゲート樹脂部を引きちぎる場合、ゲート跡の軸方向位置にバラつきが生じる。例えば、ゲート樹脂部がランナ樹脂部側に偏った位置で切断されると、ゲート跡がハウジングの底部から大きく突出するため、ゲート跡が他部材と干渉する恐れが生じる。一方、型開き時に、ハウジングの底部の材料の一部がランナ樹脂部側に取られると、ハウジングの底部にゲート跡が凹状に形成されるため、強度不足を招く恐れが生じる。上記のように治具でゲート跡を平滑化した場合でも、ゲート跡の軸方向位置のバラつきは抑えられないため、これに伴う不具合を解消することはできない。   Also, when the gate resin portion is torn off due to the mold opening, the axial position of the gate mark varies. For example, if the gate resin portion is cut at a position deviated to the runner resin portion side, the gate mark protrudes greatly from the bottom of the housing, so that the gate mark may interfere with other members. On the other hand, if a part of the material at the bottom of the housing is removed toward the runner resin portion when the mold is opened, a gate mark is formed in the bottom of the housing in a concave shape, which may cause insufficient strength. Even when the gate trace is smoothed by the jig as described above, the variation in the position of the gate trace in the axial direction cannot be suppressed, so that the problem associated therewith cannot be solved.

以上のような事情から、本発明が解決すべき技術的課題は、有底筒状を成したハウジングを樹脂で射出成形するにあたり、コンタミの発生を確実に防止すると共に、ゲート跡の軸方向位置を高精度に管理して他部材との干渉や強度低下を回避することにある。   In view of the above circumstances, the technical problem to be solved by the present invention is to prevent the occurrence of contamination in the injection molding of a housing having a bottomed cylindrical shape with resin and to prevent the occurrence of the gate mark in the axial direction. Is to be controlled with high precision to avoid interference with other members and a decrease in strength.

前記課題を解決するために、本発明は、筒状の側部と、該側部の軸方向一端を閉塞する底部とを一体に有し、樹脂で射出成形された流体動圧軸受装置用のハウジングであって、射出ゲートを閉塞する閉塞部材で成形されたゲート跡が設けられたことを特徴とするハウジングを提供する。   In order to solve the above-mentioned problems, the present invention is directed to a fluid dynamic pressure bearing device having a cylindrical side portion and a bottom portion closing one axial end of the side portion, and being injection-molded with resin. Provided is a housing, wherein a gate mark formed by a closing member for closing the injection gate is provided.

このように、本発明では、射出ゲートに閉塞部材（ニードルバルブ）で閉塞することにより、キャビティ内の溶融樹脂とランナ内の溶融樹脂とを分断する。これにより、キャビティ内の溶融樹脂を冷却して固化させた後、型開きを行うときに、キャビティ内で固化した樹脂（ハウジング）とランナ内で固化した樹脂との境界が引きちぎられることなく、両者を分離することができる。このとき、閉塞部材でハウジングのゲート跡を成形することで、ゲート跡が閉塞部材に倣った平滑な面となるため、充填材や樹脂片の脱落を確実に防止することができる。また、閉塞部材の軸方向位置を高精度に設定することで、ゲート跡の軸方向位置を高精度に管理することができる。   As described above, in the present invention, the injection resin is closed by the closing member (needle valve) to separate the molten resin in the cavity from the molten resin in the runner. Thereby, when the mold is opened after cooling and solidifying the molten resin in the cavity, the boundary between the resin (housing) solidified in the cavity and the resin solidified in the runner is not torn, and Can be separated. At this time, by forming the gate mark of the housing with the closing member, the gate mark becomes a smooth surface following the closing member, so that the filler and the resin pieces can be reliably prevented from falling off. Further, by setting the axial position of the closing member with high accuracy, the axial position of the gate mark can be managed with high accuracy.

以上のように、本発明によれば、充填材や樹脂片の脱落によるコンタミの発生を確実に防止すると共に、ゲート跡の軸方向位置を高精度に管理して、ゲート跡と他部材との干渉や凹部の形成による強度不足等の不具合を回避することができる。   As described above, according to the present invention, it is possible to reliably prevent the occurrence of contamination due to the falling off of the filler and the resin pieces, and to manage the axial position of the gate mark with high accuracy, so that the gate mark and the other members can be separated. Problems such as insufficient strength due to interference or formation of concave portions can be avoided.

流体動圧軸受装置が組み込まれたスピンドルモータの断面図である。It is sectional drawing of the spindle motor in which the fluid dynamic bearing device was built. 本発明の一実施形態に係るハウジングを備えた上記流体動圧軸受装置の断面図である。It is a sectional view of the above-mentioned fluid dynamic bearing device provided with the housing concerning one embodiment of the present invention. 上記流体動圧軸受装置に設けられた軸受スリーブの断面図である。It is sectional drawing of the bearing sleeve provided in the said fluid dynamic bearing device. 上記軸受スリーブの下面図である。It is a bottom view of the said bearing sleeve. 上記ハウジングの上面図である。It is a top view of the said housing. 上記ハウジングのゲート跡付近の断面図である。It is sectional drawing near the gate mark of the said housing. 上記ハウジングを射出成形する金型の断面図であり、溶融樹脂をキャビティ内に射出する前の状態を示す。It is sectional drawing of the metal mold | die which injects the said housing, and shows the state before inject | pouring a molten resin into a cavity. （ａ）図は上記金型の断面図、（ｂ）図は（ａ）図のＸ−Ｘ線におけるキャビティの断面図であり、何れもキャビティに溶融樹脂を満たした状態を示す。(A) is a cross-sectional view of the mold, and (b) is a cross-sectional view of the cavity taken along the line XX of (a), each showing a state in which the cavity is filled with a molten resin. 上記金型のゲートをニードルバルブで閉塞した状態を示す断面図である。It is sectional drawing which shows the state which closed the gate of the said mold with the needle valve. （ａ）（ｂ）は、ニードルバルブをゲートに挿入する様子を示す拡大断面図である。(A) (b) is an expanded sectional view which shows a mode that a needle valve is inserted in a gate. 上記金型を型開きした状態を示す断面図である。It is sectional drawing which shows the state which opened the said metal mold | die. 本発明の他の実施形態に係るハウジングのゲート跡付近の拡大断面図である。It is an expanded sectional view near the gate mark of the housing concerning other embodiments of the present invention. 本発明のさらに他の実施形態に係るハウジングのゲート跡付近の拡大断面図である。It is an expanded sectional view near the gate mark of the housing concerning still another embodiment of the present invention. 本発明のさらに他の実施形態に係るハウジングの断面図である。It is sectional drawing of the housing which concerns on another embodiment of this invention. 従来のハウジングの射出成形金型のキャビティに溶融樹脂を満たした状態を示す断面図である。It is sectional drawing which shows the state which filled the cavity of the injection mold of the conventional housing with the molten resin.

図１〜図６を用いて、ＨＤＤのディスク駆動装置のスピンドルモータに、本発明の一実施形態に係るハウジング７を有する流体動圧軸受装置を組み込んだ場合について説明する。   A case where a fluid dynamic bearing device having a housing 7 according to an embodiment of the present invention is incorporated in a spindle motor of a disk drive device of an HDD will be described with reference to FIGS.

図１に示すスピンドルモータは、流体動圧軸受装置１と、流体動圧軸受装置１の軸部材２に固定されたディスクハブ３と、半径方向隙間を介して対向させたステータコイル４およびロータマグネット５と、ブラケット６とを備える。ステータコイル４はブラケット６に固定され、ロータマグネット５はディスクハブ３に固定される。ブラケット６の内周面には、流体動圧軸受装置１のハウジング７が固定される。ディスクハブ３には、所定枚数（図示例では２枚）のディスクＤが保持される。ステータコイル４に通電すると、ロータマグネット５が回転し、これに伴って、ディスクハブ３に保持されたディスクＤが軸部材２と一体に回転する。   The spindle motor shown in FIG. 1 has a fluid dynamic pressure bearing device 1, a disk hub 3 fixed to a shaft member 2 of the fluid dynamic pressure bearing device 1, a stator coil 4 and a rotor magnet opposed to each other via a radial gap. 5 and a bracket 6. The stator coil 4 is fixed to the bracket 6, and the rotor magnet 5 is fixed to the disk hub 3. A housing 7 of the fluid dynamic bearing device 1 is fixed to an inner peripheral surface of the bracket 6. The disk hub 3 holds a predetermined number (two in the illustrated example) of disks D. When the stator coil 4 is energized, the rotor magnet 5 rotates, and accordingly, the disk D held by the disk hub 3 rotates integrally with the shaft member 2.

流体動圧軸受装置１は、図２に示すように、軸受スリーブ８と、軸受スリーブ８の内周に挿入された軸部材２と、内周面に軸受スリーブ８が固定された有底筒状のハウジング７と、ハウジング７の開口部に配設されるシール部材９とを備える。尚、以下の流体動圧軸受装置１の説明では、軸方向でハウジング７の開口側を上方、その反対側を下方というが、これは流体動圧軸受装置１の使用態様を限定する趣旨ではない。   As shown in FIG. 2, the fluid dynamic bearing device 1 has a bearing sleeve 8, a shaft member 2 inserted into the inner periphery of the bearing sleeve 8, and a bottomed cylindrical shape in which the bearing sleeve 8 is fixed to the inner peripheral surface. And a seal member 9 disposed at an opening of the housing 7. In the following description of the fluid dynamic bearing device 1, the opening side of the housing 7 is referred to as an upper side in the axial direction, and the opposite side is referred to as a lower side. However, this is not intended to limit the usage of the fluid dynamic bearing device 1. .

軸部材２は、ステンレス鋼等の金属材料で形成される。軸部材２は、軸部２ａと、軸部２ａの下端に設けられたフランジ部２ｂとを備える。軸部２ａの外周面には、軸方向に離隔した２箇所に形成され、後述する軸受スリーブ８のラジアル軸受面と半径方向に対向する円筒面２ａ１，２ａ２と、円筒面２ａ１，２ａ２の軸方向間に設けられ、円筒面２ａ１，２ａ２よりも小径な逃げ部２ａ３と、円筒面２ａ１の上方に設けられ、上方に行くほど縮径したテーパ面２ａ４とが形成される。軸部２ａの外径（特に、円筒面２ａ１，２ａ２の外径）は、例えば１〜４ｍｍ程度とされる。   The shaft member 2 is formed of a metal material such as stainless steel. The shaft member 2 includes a shaft portion 2a and a flange portion 2b provided at a lower end of the shaft portion 2a. On the outer peripheral surface of the shaft portion 2a, two cylindrical surfaces 2a1 and 2a2 which are formed at two locations separated in the axial direction and radially oppose a radial bearing surface of a bearing sleeve 8 described later, and axial directions of the cylindrical surfaces 2a1 and 2a2. A relief portion 2a3 provided between the cylindrical surfaces 2a1 and 2a2 and having a diameter smaller than that of the cylindrical surfaces 2a1 and 2a2, and a tapered surface 2a4 provided above the cylindrical surface 2a1 and reduced in diameter toward the upper side are formed. The outer diameter of the shaft portion 2a (particularly, the outer diameter of the cylindrical surfaces 2a1 and 2a2) is, for example, about 1 to 4 mm.

軸受スリーブ８は、円筒状を成し、例えば焼結金属、具体的には銅系、鉄系、あるいは銅鉄系の焼結金属で形成される。軸受スリーブ８の内周面８ａには、上下に離隔した２箇所の領域にラジアル軸受面が設けられ、各ラジアル軸受面にラジアル動圧発生部が形成される。本実施形態では、ラジアル動圧発生部として、図３に示すようなヘリングボーン形状の動圧溝８ａ１，８ａ２が形成される。図中にクロスハッチングで示す領域は、他の領域よりも内径側に盛り上がった丘部を表している（以下、同様）。図示例では、上側のラジアル軸受面に形成された動圧溝８ａ１は軸方向非対称形状とされ、具体的には、軸方向略中央に設けられた環状丘部よりも上側の動圧溝８ａ１の軸方向寸法Ｌ１が、環状丘部よりも下側の動圧溝８ａ１の軸方向寸法Ｌ２よりも大きい。一方、下側のラジアル軸受面に形成された動圧溝８ａ２は軸方向対称形状とされる。   The bearing sleeve 8 has a cylindrical shape and is formed of, for example, a sintered metal, specifically, a copper-based, iron-based, or copper-iron-based sintered metal. On the inner peripheral surface 8a of the bearing sleeve 8, radial bearing surfaces are provided in two vertically separated regions, and a radial dynamic pressure generating portion is formed on each radial bearing surface. In the present embodiment, herringbone-shaped dynamic pressure grooves 8a1 and 8a2 as shown in FIG. 3 are formed as radial dynamic pressure generating portions. The area shown by cross-hatching in the figure represents a hill that rises to the inner diameter side from other areas (the same applies hereinafter). In the illustrated example, the dynamic pressure groove 8a1 formed on the upper radial bearing surface has an asymmetric shape in the axial direction. Specifically, the dynamic pressure groove 8a1 above the annular hill portion provided substantially at the center in the axial direction is formed. The axial dimension L1 is larger than the axial dimension L2 of the dynamic pressure groove 8a1 below the annular hill. On the other hand, the dynamic pressure groove 8a2 formed on the lower radial bearing surface has an axially symmetric shape.

軸受スリーブ８の下側端面８ｂは、全面がスラスト軸受面として機能し、このスラスト軸受面にスラスト動圧発生部が形成される。本実施形態では、スラスト動圧発生部として、図４に示すようなスパイラル形状の動圧溝８ｂ１が形成される。図示例の動圧溝８ｂ１は、潤滑流体を内径側に押し込むポンプインタイプである。軸受スリーブ８の上側端面８ｄには、図３に示すように、環状溝８ｄ１と、環状溝８ｄ１の内径側に設けられた複数の半径方向溝８ｄ２とが形成される。図３及び図４に示すように、軸受スリーブ８の外周面８ｃには、複数（図示例では３本）の軸方向溝８ｃ１が円周方向等間隔に設けられる。   The entire lower surface 8b of the bearing sleeve 8 functions as a thrust bearing surface, and a thrust dynamic pressure generating portion is formed on the thrust bearing surface. In the present embodiment, a spiral dynamic pressure groove 8b1 as shown in FIG. 4 is formed as the thrust dynamic pressure generating portion. The illustrated dynamic pressure groove 8b1 is a pump-in type that pushes the lubricating fluid toward the inner diameter side. As shown in FIG. 3, an annular groove 8d1 and a plurality of radial grooves 8d2 provided on the inner diameter side of the annular groove 8d1 are formed on the upper end surface 8d of the bearing sleeve 8. As shown in FIGS. 3 and 4, a plurality (three in the illustrated example) of axial grooves 8c1 are provided on the outer peripheral surface 8c of the bearing sleeve 8 at equal intervals in the circumferential direction.

ハウジング７は、有底筒状を成した樹脂の射出成形品である。本実施形態のハウジング７は、図２に示すように、円筒状の側部７ａと、側部７ａの下端の開口部を閉塞する円盤状の底部７ｂとを一体に有する。底部７ｂの上側端面７ｂ１には、スラスト軸受隙間を形成するスラスト軸受面が設けられ、このスラスト軸受面にスラスト動圧発生部が設けられる。本実施形態では、スラスト動圧発生部として、図５に示すようなスパイラル形状の動圧溝７ｂ１０が形成される。図示例の動圧溝７ｂ１０は、スラスト軸受隙間に満たされた潤滑油を内径側に押し込むポンプインタイプである。底部７ｂの上側端面７ｂ１のうち、スラスト軸受面（動圧溝７ｂ１０の形成領域）よりも内径側の領域には、凹部７ｂ２が設けられる。底部７ｂの下側端面７ｂ３の軸心には、凹部７ｂ４が設けられる（図２参照）。図示例のハウジング７は、ハウジング７の底部７ｂのうち、後述するゲート跡７ｂ３０の形成箇所（図示例では軸心）における肉厚が、２ｍｍ以下、好ましくは１ｍｍ以下、より好ましくは０．８ｍｍ以下となっている。図示例では、底部７ｂの肉厚が、軸心で最も薄くなっている。また、強度を確保するため、底部の肉厚は０．３ｍｍ以上とすることが好ましい。   The housing 7 is an injection-molded product of a resin having a bottomed cylindrical shape. As shown in FIG. 2, the housing 7 of the present embodiment integrally includes a cylindrical side portion 7a and a disk-shaped bottom portion 7b that closes an opening at the lower end of the side portion 7a. A thrust bearing surface forming a thrust bearing gap is provided on the upper end surface 7b1 of the bottom portion 7b, and a thrust dynamic pressure generating portion is provided on the thrust bearing surface. In this embodiment, a spiral dynamic pressure groove 7b10 as shown in FIG. 5 is formed as the thrust dynamic pressure generating portion. The illustrated dynamic pressure groove 7b10 is a pump-in type that pushes the lubricating oil filled in the thrust bearing gap toward the inner diameter side. In the upper end surface 7b1 of the bottom portion 7b, a recess 7b2 is provided in a region on the inner diameter side of the thrust bearing surface (the region where the dynamic pressure groove 7b10 is formed). A recess 7b4 is provided at the axis of the lower end surface 7b3 of the bottom 7b (see FIG. 2). The thickness of the housing 7 in the illustrated example is 2 mm or less, preferably 1 mm or less, and more preferably 0.8 mm or less in the bottom 7 b of the housing 7 at the location (the axis in the illustrated example) where a gate mark 7 b 30 described later is formed. It has become. In the illustrated example, the thickness of the bottom 7b is the thinnest at the axis. Further, in order to secure strength, the bottom portion preferably has a thickness of 0.3 mm or more.

ハウジング７の表面には、ゲート跡７ｂ３０が設けられる。本実施形態では、ハウジングの７の底部７ｂの下側端面７ｂ３にゲート跡７ｂ３０が設けられる。詳しくは、図２に示されているように、ハウジング７の底部７ｂの下側端面７ｂ３の軸心、より詳しくは底部７ｂの下側端面７ｂ３に設けられた凹部７ｂ４の軸心に、点状ゲートのゲート跡７ｂ３０が設けられる。ゲート跡７ｂ３０は、その外径側に隣接した領域（図示例では凹部７ｂ４の底面）と同一平面上に連続して設けられる。   A gate mark 7b30 is provided on the surface of the housing 7. In the present embodiment, a gate mark 7b30 is provided on the lower end surface 7b3 of the bottom 7b of the housing 7. More specifically, as shown in FIG. 2, a point is formed on the axis of the lower end face 7b3 of the bottom 7b of the housing 7, more specifically, on the axis of the recess 7b4 provided on the lower end face 7b3 of the bottom 7b. A gate mark 7b30 of the gate is provided. The gate trace 7b30 is provided continuously on the same plane as a region adjacent to the outer diameter side (the bottom surface of the concave portion 7b4 in the illustrated example).

ゲート跡７ｂ３０は、後述する閉塞部材（ニードルバルブ）の先端面で成形された成形面である。すなわち、ゲート跡７ｂ３０は、樹脂の固化後に切断された面や、切断後に後加工（型成形や機械加工）が施された面ではなく、ハウジング７の射出成形と同時に成形された成形面である。また、図６に示すように、底部７ｂの下側端面７ｂ３のうち、ゲート跡７ｂ３０が形成された領域では、繊維状充填材１０が内部に押し込まれた状態となっており、図中に点線で示すようなハウジング７の表面から飛び出した繊維状充填材１０’は存在しない。   The gate mark 7b30 is a molding surface formed by a distal end surface of a closing member (needle valve) described later. That is, the gate trace 7b30 is not a surface cut after the resin is solidified or a surface that has been subjected to post-processing (molding or machining) after the cutting, but is a molding surface formed simultaneously with the injection molding of the housing 7. . As shown in FIG. 6, in the lower end surface 7b3 of the bottom 7b, in the region where the gate mark 7b30 is formed, the fibrous filler 10 is pushed into the inside, and the dotted line in the drawing is shown. There is no fibrous filler 10 'protruding from the surface of the housing 7 as shown by.

ハウジング７を形成する樹脂は、主に熱可塑性樹脂であり、例えば結晶性樹脂、具体的には液晶ポリマー（ＬＣＰ）、ポリフェニレンサルファイド（ＰＰＳ）、ポリブチレンテレフタレート（ＰＢＴ）、ポリエーテルエーテルケトン（ＰＥＥＫ）等を用いることができる。上記の樹脂には、例えば、ガラス繊維や炭素繊維等の繊維状充填材が配合され、本実施形態では炭素繊維が配合される。炭素繊維の平均繊維長は、例えば１００〜２００μｍとされる。炭素繊維の平均径は、例えば６〜８μｍとされる。樹脂に対する炭素繊維の配合割合は、例えば５〜４０ｗｔ％とされる。尚、上記の樹脂に配合する充填材は上記に限らず、上記に代えて、あるいは上記に加えて、ガラスフレーク、ガラスビーズ、金属粉、カーボンブラック、黒鉛、カーボンナノマテリアル等を配合してもよい。以上に示した充填材は、単独で、あるいは、二種以上を混合して配合しても良い。   The resin forming the housing 7 is mainly a thermoplastic resin, for example, a crystalline resin, specifically, a liquid crystal polymer (LCP), polyphenylene sulfide (PPS), polybutylene terephthalate (PBT), polyether ether ketone (PEEK) ) Etc. can be used. For example, a fibrous filler such as glass fiber or carbon fiber is blended with the above resin, and in this embodiment, carbon fiber is blended. The average fiber length of the carbon fibers is, for example, 100 to 200 μm. The average diameter of the carbon fibers is, for example, 6 to 8 μm. The mixing ratio of the carbon fiber to the resin is, for example, 5 to 40 wt%. In addition, the filler to be added to the above resin is not limited to the above, and instead of or in addition to the above, glass flakes, glass beads, metal powder, carbon black, graphite, carbon nanomaterial, etc. Good. The fillers described above may be used alone or in combination of two or more.

シール部材９は、樹脂あるいは金属で環状に形成され、ハウジング７の側部７ａの内周面７ａ１の上端部に固定される（図２参照）。シール部材９の下側端面９ｂは、軸受スリーブ８の上側端面８ｄに当接している。シール部材９の内周面９ａは、軸部２ａの外周面に設けられたテーパ面２ａ４と半径方向で対向し、これらの間に下方へ向けて半径方向寸法を漸次縮小させた楔状のシール空間Ｓが形成される。軸部材２の回転時には、シール空間Ｓが毛細管力シールおよび遠心力シールとして機能し、ハウジング７の内部に満たされた潤滑油の外部への漏れ出しを防止する。   The seal member 9 is formed in an annular shape from resin or metal, and is fixed to the upper end of the inner peripheral surface 7a1 of the side portion 7a of the housing 7 (see FIG. 2). The lower end surface 9b of the seal member 9 is in contact with the upper end surface 8d of the bearing sleeve 8. An inner peripheral surface 9a of the seal member 9 radially opposes a tapered surface 2a4 provided on an outer peripheral surface of the shaft portion 2a, and a wedge-shaped seal space between which a radial dimension is gradually reduced downward. S is formed. When the shaft member 2 rotates, the seal space S functions as a capillary force seal and a centrifugal force seal, and prevents the lubricating oil filled in the housing 7 from leaking to the outside.

上記の構成部品からなる流体動圧軸受装置１の内部に、潤滑流体としての潤滑油が注入される。これにより、軸受スリーブ８の内部空孔を含む流体動圧軸受装置１の内部空間が潤滑油で満たされ、油面は常にシール空間Ｓの範囲内に維持される。尚、潤滑流体として、潤滑油の他、グリースや磁性流体を使用してもよい。   A lubricating oil as a lubricating fluid is injected into the fluid dynamic bearing device 1 including the above components. Thus, the internal space of the fluid dynamic bearing device 1 including the internal hole of the bearing sleeve 8 is filled with the lubricating oil, and the oil level is always maintained within the range of the seal space S. As the lubricating fluid, grease or magnetic fluid may be used in addition to lubricating oil.

軸部材２が回転すると、軸受スリーブ８の内周面８ａ（ラジアル軸受面）と軸部２ａの外周面（円筒面２ａ１，２ａ２）との間にラジアル軸受隙間が形成される。そして、軸受スリーブ８の内周面８ａに形成された動圧溝８ａ１，８ａ２によりラジアル軸受隙間の油膜の圧力が高められ、軸部材２を回転自在に非接触支持する第１ラジアル軸受部Ｒ１及び第２ラジアル軸受部Ｒ２が構成される。   When the shaft member 2 rotates, a radial bearing gap is formed between the inner peripheral surface 8a (radial bearing surface) of the bearing sleeve 8 and the outer peripheral surfaces (cylindrical surfaces 2a1, 2a2) of the shaft portion 2a. The pressure of the oil film in the radial bearing gap is increased by the dynamic pressure grooves 8a1 and 8a2 formed on the inner peripheral surface 8a of the bearing sleeve 8, and the first radial bearing portion R1 and the first radial bearing portion R1 rotatably support the shaft member 2 in a non-contact manner. The second radial bearing portion R2 is configured.

これと同時に、フランジ部２ｂの上側端面２ｂ１と軸受スリーブ８の下側端面８ｂ（スラスト軸受面）との間にスラスト軸受隙間が形成されると共に、フランジ部２ｂの下側端面２ｂ２とハウジング７の底部７ｂの上側端面７ｂ１（スラスト軸受面）との間にスラスト軸受隙間が形成される。そして、軸受スリーブ８の下側端面８ｂに形成された動圧溝８ｂ１、及びハウジング７の底部７ｂの上側端面７ｂ１に形成された動圧溝７ｂ１０により、各スラスト軸受隙間の油膜の圧力が高められ、軸部材２を両スラスト方向に回転自在に非接触支持する第１スラスト軸受部Ｔ１及び第２スラスト軸受部Ｔ２が構成される。   At the same time, a thrust bearing gap is formed between the upper end surface 2b1 of the flange portion 2b and the lower end surface 8b (thrust bearing surface) of the bearing sleeve 8, and the lower end surface 2b2 of the flange portion 2b and the housing 7 A thrust bearing gap is formed between the bottom portion 7b and the upper end surface 7b1 (thrust bearing surface). The pressure of the oil film in each thrust bearing gap is increased by the dynamic pressure groove 8b1 formed on the lower end surface 8b of the bearing sleeve 8 and the dynamic pressure groove 7b10 formed on the upper end surface 7b1 of the bottom 7b of the housing 7. A first thrust bearing portion T1 and a second thrust bearing portion T2 for rotatably supporting the shaft member 2 in both thrust directions in a non-contact manner are configured.

本実施形態では、軸部材２のフランジ部２ｂの外径側の空間が、軸受スリーブ８の外周面８ｃの軸方向溝８ｃ１及び上側端面８ｄの環状溝８ｄ１及び半径方向溝８ｄ２を介して、シール空間Ｓと連通している。これにより、フランジ部２ｂの外径側の空間が常に大気圧に近い状態とされ、この空間における負圧の発生を防止できる。特に、本実施形態では、軸受スリーブ８の内周面８ａの上側領域に形成された動圧溝８ａ１，８ａ２が軸方向非対称形状であるため、軸部材２の回転に伴ってラジアル軸受隙間の潤滑油を下向きに押し込むポンピング力が発生する。これにより、ラジアル軸受隙間→第１スラスト軸受部Ｔ１のスラスト軸受隙間→軸方向溝８ｃ１→環状溝８ｄ１及び半径方向溝８ｄ２→ラジアル軸受隙間という経路を潤滑油が循環するため、ハウジング７の内部に満たされた潤滑油に局部的な負圧が発生することを確実に防止できる。   In this embodiment, the space on the outer diameter side of the flange portion 2b of the shaft member 2 is sealed by the axial groove 8c1 of the outer peripheral surface 8c of the bearing sleeve 8 and the annular groove 8d1 and the radial groove 8d2 of the upper end surface 8d. It communicates with the space S. As a result, the space on the outer diameter side of the flange portion 2b is always kept close to the atmospheric pressure, and the generation of negative pressure in this space can be prevented. In particular, in the present embodiment, since the dynamic pressure grooves 8a1 and 8a2 formed in the upper region of the inner peripheral surface 8a of the bearing sleeve 8 have an asymmetric shape in the axial direction, lubrication of the radial bearing gap with the rotation of the shaft member 2 is performed. A pumping force is generated that pushes the oil downward. As a result, the lubricating oil circulates through the path of the radial bearing gap → the thrust bearing gap of the first thrust bearing portion T1 → the axial groove 8c1 → the annular groove 8d1 and the radial groove 8d2 → the radial bearing gap. The generation of a local negative pressure in the filled lubricating oil can be reliably prevented.

以下、上記のハウジング７の製造方法（射出成形方法）を、図７〜図１１を用いて説明する。   Hereinafter, the manufacturing method (injection molding method) of the housing 7 will be described with reference to FIGS.

図７に示すように、ハウジング７を射出成形する金型２０は、固定型２１と、可動型２２とからなる。可動型２２は図中上下方向に移動方向であり、固定型２１と可動型２２とを型締めすることで、キャビティ２３が形成される。キャビティ２３は、ハウジング７の側部７ａを成形する円筒部２３ａと、底部７ｂを成形する円盤部２３ｂとからなる。本実施形態では、金型２０が、可動型２２の移動方向（すなわち型開閉方向）が水平となるように配置される。   As shown in FIG. 7, a mold 20 for injection-molding the housing 7 includes a fixed mold 21 and a movable mold 22. The movable die 22 moves in the vertical direction in the drawing, and the cavity 23 is formed by clamping the fixed die 21 and the movable die 22. The cavity 23 includes a cylindrical portion 23a for forming the side portion 7a of the housing 7 and a disk portion 23b for forming the bottom portion 7b. In the present embodiment, the mold 20 is arranged such that the moving direction of the movable mold 22 (that is, the mold opening and closing direction) is horizontal.

固定型２１には、ノズル２４と、ノズル２４の内周に設けられたランナ２５と、ランナ２５とキャビティ２３とを連通する射出ゲート２６（以下、単に「ゲート２６」と言う）とが設けられる。ゲート２６は、点状ゲートであり、ハウジング７の底部７ｂの外部側端面を成形する成形面２１ａの軸心に設けられる。ノズル２４には、図示しないヒータが設けられており、これにより、ランナ２５内の樹脂を常に溶融状態で維持する、いわゆるホットランナが構成される（図中、溶融樹脂を散点で示している）。金型２０には、ゲート２６を開閉する閉塞部材が設けられる。本実施形態では、ノズル２４の内周に、閉塞部材としてのニードルバルブ２７が設けられる。ニードルバルブ２７の外径は、ゲート２６の内径と略同径であり、両者を嵌合させることでゲート２６を閉塞することができる。ニードルバルブ２７は、図示しないシリンダ等の駆動手段により、ゲート２６を閉塞する閉塞位置（図７参照）と、ゲート２６を開放する開放位置（図８参照）との間で、図中上下方向に移動可能とされる。   The fixed die 21 is provided with a nozzle 24, a runner 25 provided on the inner periphery of the nozzle 24, and an injection gate 26 (hereinafter simply referred to as “gate 26”) that connects the runner 25 and the cavity 23. . The gate 26 is a point gate, and is provided at the axis of the molding surface 21 a that forms the outer end surface of the bottom 7 b of the housing 7. The nozzle 24 is provided with a heater (not shown), which forms a so-called hot runner that always maintains the resin in the runner 25 in a molten state (in the figure, the molten resin is indicated by dotted points). ). The mold 20 is provided with a closing member that opens and closes the gate 26. In the present embodiment, a needle valve 27 as a closing member is provided on the inner periphery of the nozzle 24. The outer diameter of the needle valve 27 is substantially the same as the inner diameter of the gate 26, and the gate 26 can be closed by fitting them together. The needle valve 27 is vertically moved in the figure between a closed position (see FIG. 7) for closing the gate 26 and an open position (see FIG. 8) for opening the gate 26 by a driving means such as a cylinder (not shown). It can be moved.

固定型２１と可動型２２を型締めした状態で、図８（ａ）に示すようにニードルバルブ２７をゲート２６の内周から図中上方に退避させることにより、ランナ２５とキャビティ２３とがゲート２６を介して連通し、ランナ２５内の溶融樹脂がゲート２６からキャビティ２３内に射出される。このとき、固定型２１の成形面２１ａの軸心に設けられたゲート２６から射出された溶融樹脂は、キャビティ２３の円盤部２３ｂを外径側へ流動し｛図８（ｂ）の矢印参照｝、さらにキャビティ２３の円筒部２３ａを図中下方に流動する｛図８（ａ）の矢印参照｝。これにより、キャビティ２３内に周方向で均一に溶融樹脂が行き渡り、ウェルドラインの形成を回避できる。   With the fixed mold 21 and the movable mold 22 clamped, the needle valve 27 is retracted upward from the inner periphery of the gate 26 in the figure as shown in FIG. The molten resin in the runner 25 is injected from the gate 26 into the cavity 23 via the gate 26. At this time, the molten resin injected from the gate 26 provided at the axis of the molding surface 21a of the fixed die 21 flows through the disk portion 23b of the cavity 23 toward the outer diameter side (see the arrow in FIG. 8B). Then, it flows downward through the cylindrical portion 23a of the cavity 23 (see the arrow in FIG. 8A). Thereby, the molten resin is uniformly distributed in the circumferential direction in the cavity 23, and the formation of a weld line can be avoided.

こうしてキャビティ２３内に満たされた溶融樹脂に保圧をかけた状態で、図９に示すようにニードルバルブ２７を図中下方に前進させてゲート２６の内周に挿入する。これにより、図１０（ａ）及び（ｂ）に示すように、ゲート２６内の溶融樹脂がニードルバルブ２７によりキャビティ２３に押し込まれる。そして、ゲート２６とニードルバルブ２７とが嵌合することで、ゲート２６が閉塞され、キャビティ２３内の溶融樹脂とランナ２５内の溶融樹脂とが分断される。この状態で、キャビティ２３内の溶融樹脂を冷却することにより、キャビティ２３内の樹脂が固化してハウジング７が成形される。このとき、ハウジング７の底部７ｂの外側端面（図９では上側端面）７ｂ３の軸心に、ニードルバルブ２７の先端面の形状が転写され、ゲート跡７ｂ３０が成形される。これにより、ゲート跡７ｂ３０がニードルバルブ２７の先端面に倣った平滑な面となる。また、ニードルバルブ２７の先端面の軸方向位置を高精度に設定することで、ゲート跡７ｂ３０の軸方向位置を高精度に管理することができる。   In the state where the pressure of the molten resin filled in the cavity 23 is maintained, the needle valve 27 is advanced downward in the figure and inserted into the inner periphery of the gate 26 as shown in FIG. This causes the molten resin in the gate 26 to be pushed into the cavity 23 by the needle valve 27, as shown in FIGS. When the gate 26 and the needle valve 27 are fitted, the gate 26 is closed, and the molten resin in the cavity 23 and the molten resin in the runner 25 are separated. By cooling the molten resin in the cavity 23 in this state, the resin in the cavity 23 is solidified and the housing 7 is formed. At this time, the shape of the tip end surface of the needle valve 27 is transferred to the axis of the outer end surface (upper end surface in FIG. 9) 7b3 of the bottom portion 7b of the housing 7, and the gate mark 7b30 is formed. Thereby, the gate mark 7b30 becomes a smooth surface following the tip surface of the needle valve 27. In addition, by setting the axial position of the distal end surface of the needle valve 27 with high accuracy, the axial position of the gate mark 7b30 can be managed with high accuracy.

その後、図１１に示すように、可動型２２を固定型２１から離反させて、型開きを行う。このとき、ハウジング７とランナ２５内の樹脂とが既に分離されているため、型開きを行う際に、固化した樹脂の一部が引きちぎられることがない。これにより、ハウジング７のゲート跡７ｂ３０が平滑な面で維持されるため、ゲート跡７ｂ３０からの充填材や樹脂片の脱落を防止して、コンタミの発生を確実に防止することができる。また、ゲート跡７ｂ３０の軸方向位置が高精度に設定されているため、ゲート跡７ｂ３０が底部７ｂから下方に大きく突出して他部材と干渉したり、ゲート跡７ｂ３０が凹状に形成されて底部７ｂの強度が不足したりする事態を回避できる。   Thereafter, as shown in FIG. 11, the movable mold 22 is separated from the fixed mold 21 to open the mold. At this time, since the housing 7 and the resin in the runner 25 have already been separated, a part of the solidified resin will not be torn off when the mold is opened. Thereby, since the gate trace 7b30 of the housing 7 is maintained on a smooth surface, it is possible to prevent the filler or the resin piece from falling off from the gate trace 7b30, and to surely prevent the occurrence of contamination. In addition, since the axial position of the gate trace 7b30 is set with high accuracy, the gate trace 7b30 greatly protrudes downward from the bottom 7b and interferes with other members, or the gate trace 7b30 is formed in a concave shape so that the bottom 7b is formed. Insufficient strength can be avoided.

本発明は、上記の実施形態に限られない。以下、本発明の他の実施形態について説明するが、上記の実施形態と同様の機能を有する部位は、同一の符号を付して重複説明を省略する。   The present invention is not limited to the above embodiment. Hereinafter, other embodiments of the present invention will be described. Parts having functions similar to those of the above-described embodiments will be denoted by the same reference numerals, and redundant description will be omitted.

本発明に係るゲート跡７ｂ３０は、ニードルバルブ２７の先端面で成形されるため、成形時にニードルバルブ２７の軸方向位置を調整することで、ゲート跡７ｂ３０を任意の軸方向位置に配することができる。従って、図２に示すようにゲート跡７ｂ３０をその外周に隣接した領域と面一に設ける他、例えば図１２に示すように、ゲート跡７ｂ３０を、その外周に隣接した領域よりも図中上方に凹ませて形成してもよい。この場合、ゲート跡７ｂ３０が底部７ｂの下側端面７ｂ３から図中下方に突出することがないため、ゲート跡７ｂ３０と他部材との干渉を確実に回避できる。   Since the gate mark 7b30 according to the present invention is formed at the tip end surface of the needle valve 27, the gate mark 7b30 can be arranged at an arbitrary axial position by adjusting the axial position of the needle valve 27 during molding. it can. Therefore, as shown in FIG. 2, in addition to providing the gate trace 7b30 flush with the region adjacent to the outer periphery, for example, as shown in FIG. 12, the gate trace 7b30 is positioned higher in the figure than the region adjacent to the outer periphery. It may be formed by denting. In this case, since the gate trace 7b30 does not protrude downward in the drawing from the lower end surface 7b3 of the bottom 7b, interference between the gate trace 7b30 and other members can be reliably avoided.

あるいは図１３に示すように、ゲート跡７ｂ３０を、その外周に隣接した領域よりも図中下方に突出させて形成してもよい。この場合、ゲート跡７ｂ３０の形成により底部７ｂが薄肉化されることがないため、底部７ｂの強度低下を回避することができる。   Alternatively, as shown in FIG. 13, the gate trace 7b30 may be formed so as to protrude downward in the figure from a region adjacent to the outer periphery thereof. In this case, since the bottom 7b is not thinned by the formation of the gate trace 7b30, a decrease in the strength of the bottom 7b can be avoided.

また、上記の実施形態では、ハウジング７の底部７ｂの下側端面７ｂ３の軸心に凹部７ｂ４を設け、この凹部７ｂ４にゲート跡７ｂ３０を設けているが、これに限られない。例えば、図１４に示すように、底部７ｂの下側端面７ｂ３の全域を段差の無い平坦面とし、その軸心にゲート跡７ｂ３０を設けてもよい。この場合、ゲート跡７ｂ３０と他部材との干渉を確実に回避するために、ゲート跡７ｂ３０は、図１４に示すように底部７ｂの下側端面７ｂ３と面一に形成するか、あるいは、図１２に示すように底部７ｂの下側端面７ｂ３の一部を凹ませて形成することが好ましい。   In the above-described embodiment, the recess 7b4 is provided in the axis of the lower end surface 7b3 of the bottom 7b of the housing 7, and the gate mark 7b30 is provided in the recess 7b4. However, the present invention is not limited to this. For example, as shown in FIG. 14, the entire area of the lower end surface 7b3 of the bottom portion 7b may be a flat surface with no step, and the gate mark 7b30 may be provided at the axis thereof. In this case, in order to reliably avoid interference between the gate trace 7b30 and other members, the gate trace 7b30 is formed flush with the lower end surface 7b3 of the bottom 7b as shown in FIG. It is preferable that a part of the lower end surface 7b3 of the bottom portion 7b be recessed as shown in FIG.

また、ハウジング７を形成する金型２０のゲート２６の位置は上記に限られない。例えば、金型２０のうち、底部７ｂの内部側端面（図２の上側端面７ｂ１）を成形する成形面の軸心に、点状ゲートを設けてもよい。あるいは、底部７ｂの外部側あるいは内部側の端面を成形する成形面に、円周方向に離隔した複数の点状ゲートを設けてもよい。ただし、キャビティ２３に溶融樹脂を均一に行き渡らせ、且つ、ウェルドラインが形成されないようにするためには、底部７ｂの端面を成形する成形面の軸心に点状ゲートを設けることが好ましい。   Further, the position of the gate 26 of the mold 20 forming the housing 7 is not limited to the above. For example, a point gate may be provided at the axis of the molding surface of the mold 20 for molding the inner end surface (the upper end surface 7b1 in FIG. 2) of the bottom portion 7b. Alternatively, a plurality of dot-shaped gates spaced in the circumferential direction may be provided on a molding surface for molding the outer or inner end surface of the bottom portion 7b. However, in order to spread the molten resin evenly in the cavity 23 and prevent the weld line from being formed, it is preferable to provide a point gate at the axis of the molding surface for molding the end face of the bottom 7b.

また、上記の実施形態では、軸受スリーブ８の内周面８ａにヘリングボーン形状の動圧溝８ａ１，８ａ２を形成した場合を示したが、これに限らず、スパイラル形状の動圧溝や、軸方向に沿って延びるステップ形状の動圧溝を形成してもよい。また、上記の実施形態では、軸受スリーブ８の内周面８ａの軸方向に離隔した２箇所に動圧溝８ａ１，８ａ２を形成したが、これらを軸方向に連続させてもよいし、あるいは、へリングボーン形状の動圧溝を一組のみ形成してもよい。   In the above-described embodiment, the case where the herringbone-shaped dynamic pressure grooves 8a1 and 8a2 are formed on the inner peripheral surface 8a of the bearing sleeve 8 has been described. However, the present invention is not limited thereto. A step-shaped dynamic pressure groove extending along the direction may be formed. Further, in the above-described embodiment, the dynamic pressure grooves 8a1 and 8a2 are formed in the inner peripheral surface 8a of the bearing sleeve 8 at two positions separated in the axial direction. However, these may be continuous in the axial direction. Only one set of herringbone-shaped dynamic pressure grooves may be formed.

また、上記の実施形態では、軸受スリーブ８の下側端面８ｂ及びハウジング７の底部７ｂの上側端面７ｂ１に、スパイラル形状の動圧溝８ｂ１，７ｂ１０を形成した場合を示したが、これに限らず、ヘリングボーン形状やステップ形状等の他の形状の動圧溝を形成してもよい。   In the above-described embodiment, the case where the spiral-shaped dynamic pressure grooves 8b1 and 7b10 are formed on the lower end surface 8b of the bearing sleeve 8 and the upper end surface 7b1 of the bottom 7b of the housing 7 has been described. Alternatively, a dynamic pressure groove having another shape such as a herringbone shape or a step shape may be formed.

また、上記の実施形態では、軸受スリーブ８の内周面８ａ、下側端面８ｂ、及びハウジングの底部７ｂの上側端面７ｂ１にそれぞれ動圧発生部（動圧溝）を形成した場合を示したが、これらの面と軸受隙間を介して対向する軸部材２の外周面（円筒面２ａ１，２ａ２）、フランジ部２ｂの上側端面２ｂ１及び下側端面２ｂ２に動圧発生部を形成してもよい。また、軸受スリーブ８の内周面８ａ及び軸部材２の外周面の双方を円筒面とし、真円軸受を構成してもよい。この場合、軸部材２の振れ回りにより、ラジアル軸受隙間の潤滑流体に動圧作用が発生する。   Further, in the above-described embodiment, the case where the dynamic pressure generating portions (dynamic pressure grooves) are formed on the inner peripheral surface 8a, the lower end surface 8b of the bearing sleeve 8, and the upper end surface 7b1 of the bottom portion 7b of the housing is shown. A dynamic pressure generating portion may be formed on the outer peripheral surfaces (cylindrical surfaces 2a1, 2a2) of the shaft member 2 facing these surfaces via the bearing gap, and the upper end surface 2b1 and the lower end surface 2b2 of the flange portion 2b. Further, both the inner peripheral surface 8a of the bearing sleeve 8 and the outer peripheral surface of the shaft member 2 may be cylindrical surfaces to form a perfect circular bearing. In this case, the whirling of the shaft member 2 generates a dynamic pressure action on the lubricating fluid in the radial bearing gap.

また、上記の実施形態では、軸部材２が回転する軸回転型の流体動圧軸受装置を示したが、これに限らず、軸部材２が固定され、軸受スリーブ８及びハウジング７が回転する軸固定型の流体動圧軸受装置や、軸部材２及び軸受スリーブ８等の双方が回転する流体動圧軸受装置に本発明を適用することもできる。   Further, in the above-described embodiment, the shaft rotation type fluid dynamic pressure bearing device in which the shaft member 2 rotates is shown. However, the present invention is not limited to this, and the shaft member 2 is fixed, and the bearing sleeve 8 and the housing 7 rotate. The present invention can also be applied to a fixed type fluid dynamic bearing device or a fluid dynamic bearing device in which both the shaft member 2 and the bearing sleeve 8 rotate.

また、上記の流体動圧軸受装置は、ＨＤＤのスピンドルモータに限らず、他の情報機器のスピンドルモータ、レーザビームプリンタのポリゴンスキャナモータ、プロジェクタのカラーホイール、あるいは電気機器のファンモータに適用することができる。   Further, the fluid dynamic bearing device described above is not limited to the spindle motor of the HDD, but may be applied to a spindle motor of another information device, a polygon scanner motor of a laser beam printer, a color wheel of a projector, or a fan motor of an electric device. Can be.

１ 流体動圧軸受装置
２ 軸部材
７ ハウジング
７ａ 側部
７ｂ 底部
７ｂ３０ ゲート跡
８ 軸受スリーブ
９ シール部材
１０ 繊維状充填材
２０ 金型
２１ 固定型
２２ 可動型
２３ キャビティ
２４ ノズル
２５ ランナ
２６ 射出ゲート
２７ ニードルバルブ（閉塞部材）
Ｒ１，Ｒ２ ラジアル軸受部
Ｔ１，Ｔ２ スラスト軸受部
Ｓ シール空間 Reference Signs List 1 fluid dynamic bearing device 2 shaft member 7 housing 7a side portion 7b bottom portion 7b30 gate mark 8 bearing sleeve 9 seal member 10 fibrous filler 20 mold 21 fixed mold 22 movable mold 23 cavity 24 nozzle 25 runner 26 injection gate 27 needle Valve (blocking member)
R1, R2 Radial bearings T1, T2 Thrust bearing S Sealed space

Claims (3)

筒状の側部と、該側部の軸方向一端を閉塞する底部とを一体に有し、繊維状充填材を含む樹脂で射出成形され、ＨＤＤのディスク駆動装置のスピンドルモータに組み込まれる流体動圧軸受装置用のハウジングであって、
常に溶融状態で維持させた前記樹脂を射出する射出ゲートを閉塞する閉塞部材で成形されたゲート跡が設けられ、
前記ゲート跡が形成された領域では前記繊維状充填材が内部に押し込まれた状態となっており、前記ゲート跡の表面から前記繊維状充填材が飛び出していないことを特徴とするハウジング。Fluid dynamics that have a cylindrical side part and a bottom part that closes one axial end of the side part, are injection-molded with a resin containing a fibrous filler, and incorporated into a spindle motor of an HDD disk drive. A housing for a pressure bearing device,
A gate mark formed by a closing member that closes an injection gate that injects the resin always kept in a molten state is provided,
The housing, wherein the fibrous filler is pushed into the region where the gate mark is formed, and the fibrous filler does not protrude from the surface of the gate mark. 請求項１記載のハウジングと、前記ハウジングの側部の内周面に固定された軸受スリーブと、前記軸受スリーブの内周に挿入された軸部材と、前記軸受スリーブの内周面と前記軸部材の外周面との間に形成されるラジアル軸受隙間の流体圧で前記軸部材をラジアル方向に支持するラジアル軸受部と、前記軸部材の端面と前記ハウジングの底部の内部側の端面との間に形成されるスラスト軸受隙間の流体圧で前記軸部材を軸方向に支持するスラスト軸受部とを備え、ＨＤＤのディスク駆動装置のスピンドルモータに組み込まれる流体動圧軸受装置。   The housing according to claim 1, a bearing sleeve fixed to an inner peripheral surface of a side portion of the housing, a shaft member inserted into an inner periphery of the bearing sleeve, an inner peripheral surface of the bearing sleeve, and the shaft member. A radial bearing portion for supporting the shaft member in a radial direction by a fluid pressure of a radial bearing gap formed between the shaft member and an outer end surface between an end surface of the shaft member and an inner end surface of a bottom portion of the housing. A fluid dynamic pressure bearing device comprising: a thrust bearing portion for axially supporting the shaft member by a fluid pressure in a formed thrust bearing gap; 請求項２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たＨＤＤのディスク駆動装置のスピンドルモータ。   A spindle motor for a disk drive of an HDD, comprising the fluid dynamic bearing device according to claim 2, a stator coil, and a rotor magnet.
JP2015053304A 2015-03-17 2015-03-17 Housing for fluid dynamic bearing device Expired - Fee Related JP6625332B2 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP2015053304A JP6625332B2 (en) 2015-03-17 2015-03-17 Housing for fluid dynamic bearing device
PCT/JP2016/056958 WO2016147928A1 (en) 2015-03-17 2016-03-07 Housing, fluid dynamic pressure bearing device with same, and method for manufacturing housing

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2015053304A JP6625332B2 (en) 2015-03-17 2015-03-17 Housing for fluid dynamic bearing device

Publications (2)

Publication Number Publication Date
JP2016173136A JP2016173136A (en) 2016-09-29
JP6625332B2 true JP6625332B2 (en) 2019-12-25

Family

ID=57009548

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2015053304A Expired - Fee Related JP6625332B2 (en) 2015-03-17 2015-03-17 Housing for fluid dynamic bearing device

Country Status (1)

Country Link
JP (1) JP6625332B2 (en)

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5821450A (en) * 1981-07-31 1983-02-08 Citizen Watch Co Ltd Plastic part for watch
JP2998144B2 (en) * 1991-10-17 2000-01-11 三菱マテリアル株式会社 Valve gate type mold equipment
JP3452988B2 (en) * 1994-09-22 2003-10-06 不二精機株式会社 Valve gate type mold equipment
US5845853A (en) * 1996-12-02 1998-12-08 Friedman; Michael Nozzle assembly for expelling a viscous mass
JPH11105841A (en) * 1997-10-01 1999-04-20 Kao Corp Plastic container
JPH11254490A (en) * 1998-03-12 1999-09-21 Sekisui Chem Co Ltd Mold for injection molding and method for injection molding
US6769901B2 (en) * 2000-04-12 2004-08-03 Mold-Masters Limited Injection nozzle system for an injection molding machine
JP2002355857A (en) * 2001-05-31 2002-12-10 Mitsubishi Materials Corp Valve gate-type mold assembly
JP4808457B2 (en) * 2004-09-27 2011-11-02 Ｎｔｎ株式会社 Hydrodynamic bearing device and manufacturing method thereof

Also Published As

Publication number Publication date
JP2016173136A (en) 2016-09-29

Similar Documents

Publication Publication Date Title
US8267588B2 (en) Fluid lubrication bearing device and method of manufacturing the same
WO2005098252A1 (en) Dynamic pressure bearing device
US8107190B2 (en) Fluid bearing device, method of manufacturing the same, and disk drive device
JP4808457B2 (en) Hydrodynamic bearing device and manufacturing method thereof
JP2007024146A (en) Dynamic pressure bearing device
JP2007069393A (en) Method for forming dynamic pressure groove
US7431505B2 (en) Fluid lubrication bearing apparatus
JP2008130208A (en) Hydrodynamic bearing device and its manufacturing method
JP4476670B2 (en) Hydrodynamic bearing device
JP2007255449A (en) Fluid bearing device
JP2005061557A (en) Fluid dynamic bearing unit and manufacturing method therefor
WO2008065855A1 (en) Dynamic-pressure bearing device, and bearing member manufacturing method
JP6625332B2 (en) Housing for fluid dynamic bearing device
JP2016173137A (en) Housing for fluid dymanic pressure bearing device and manufacturing method for the same
JP4738964B2 (en) Hydrodynamic bearing device and motor having the same
WO2016147928A1 (en) Housing, fluid dynamic pressure bearing device with same, and method for manufacturing housing
JP6297309B2 (en) Fluid dynamic bearing device and manufacturing method thereof
JP2005265119A (en) Fluid bearing device and its manufacturing method
JP2010043666A (en) Dynamic pressure bearing device
JP5627996B2 (en) Housing for fluid dynamic pressure bearing device, method for manufacturing the same, and fluid dynamic pressure bearing device including the same
JP2009011018A (en) Fluid bearing device, and manufacturing method thereof
JP2007092845A (en) Bearing device
JP2007100904A (en) Fluid bearing device and its manufacturing method
JP6347986B2 (en) Fluid dynamic bearing device and motor including the same
JP2005061486A (en) Dynamic pressure bearing device, its manufacturing method, and recording disk driving device

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20180226

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20181105

A521 Request for written amendment filed

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20181221

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20190516

A521 Request for written amendment filed

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20190711

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20191113

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20191127

R150 Certificate of patent or registration of utility model

Ref document number: 6625332

Country of ref document: JP

Free format text: JAPANESE INTERMEDIATE CODE: R150

LAPS Cancellation because of no payment of annual fees