JP3884607B2

JP3884607B2 - Dynamic pressure groove processing equipment

Info

Publication number: JP3884607B2
Application number: JP2000143347A
Authority: JP
Inventors: 義和市山
Original assignee: Nidec Corp
Current assignee: Nidec Corp
Priority date: 2000-05-16
Filing date: 2000-05-16
Publication date: 2007-02-21
Anticipated expiration: 2020-05-16
Also published as: JP2001322034A

Description

【０００１】
【発明の属する技術分野】
本発明は、スリーブの内周面やシャフト（軸体）の外周面等に動圧溝を形成する動圧溝加工装置に関する。
【０００２】
【従来の技術】
従来、例えば、ハードディスク等の記録媒体を回転駆動させるためのモータ等の回転機械には、流体を利用した動圧軸受が用いられることがあり、この動圧軸受部に設けられるスリーブの内周面やシャフトの外周面には所定形状の動圧溝が形成されている。
【０００３】
このような動圧溝を上記スリーブ等の軸受素材に形成する方法として、例えば、特開平１０−８６０２０号公報に開示されているような電解加工法が採用されることがある。
【０００４】
この電解加工法は、所定形状の電極を有する金型と軸受素材の被加工面とを所定の間隙を介して対向配置し、その間隙に所定の電解液を流しながら、上記金型の電極と軸受素材の被加工面との間で通電させることにより、上記電極の形状に対応する溝（動圧溝）を軸受素材の被加工面に形成するというものである。なお、上記スリーブの内周面に動圧溝を形成する場合には、この内周面に対向する外周面を有しこの外周面に所定形状の電極が形成された金型が用いられ、シャフトの外周面に動圧溝を形成する場合には、この外周面に対向する内周面を有しこの内周面に所定形状の電極が形成された金型が用いられる。
【０００５】
【発明が解決しようとする課題】
ところで、上記のように軸受素材を加工する場合に、この軸受素材と金型との間の間隙が全周にわたって一定でないと、通電量が上記電極及び軸受素材の各部位によって異なることになり、その結果、形成する動圧溝の深さや幅にばらつきが生じるという問題が発生する。
【０００６】
本発明は、上記に鑑みてなされたもので、主として上記動圧軸受部を構成する動圧溝を軸受素材に形成する場合に、形成する動圧溝の深さや幅にばらつきが発生するのを防止することを目的とする。
【０００７】
【課題を解決するための手段】
請求項１に記載の発明は、円周状周面に所定形状の電極が形成された金型の周面に被加工物の円周状周面を対向させ、上記電極と上記被加工物との隙間に電解液を満たした状態で、上記電極と上記被加工物との間で通電を行わせて上記被加工物の円周状周面に上記電極に対応する動圧溝を形成する動圧溝加工装置において、上記電極と上記被加工物との調芯を行う調芯機構部を備え、上記調芯機構部は、上記金型の一部に設けられ、上記電極と同心状に配置された円錐状のテーパ部と、同一径を有する少なくとも３個の球体と、上記各球体を上記テーパ部の側面と上記被加工物の円周状周面とに当接させ、且つ、上記テーパ部の側面と上記被加工物の円周状周面との間隙を周方向に等しくするべく、それぞれ周方向の所定位置に保持する保持部材と、を備え、上記テーパ部と上記被加工物との間には上記各球体が介されており、上記各球体は、電気絶縁性を示すものであることを特徴とする。
【０００８】
この発明によれば、金型の一部に設けられた軸芯方向に向かう円錐状のテーパ部と、同一径を有する少なくとも３個の球体と、上記各球体を上記テーパ部の側面と上記被加工物の表面とに当接させるべく、それぞれ周方向の所定位置に保持する保持部材とを備える調芯機構部を設けたから、金型の円周状周面から上記被加工物の表面までの距離が等しくなり、被加工物の軸芯位置と電極の軸芯位置とが一致することになる。したがって、被加工物と金型とが全周にわたって一定の間隙を介して対向した状態で被加工物が加工されることになり、形成する溝の深さや幅にばらつきが発生するのを防止することができる。
【００１０】
請求項２に記載の発明は、請求項１に記載の溝加工装置において、上記調芯機構部は、金型の軸芯方向に少なくとも２個以上設けられていることを特徴とする。この発明によれば、より確実に被加工物の軸芯位置を金型の軸芯位置に一致させることができる。
【００１１】
請求項３に記載の発明は、請求項１又は２のいずれかに記載の溝加工装置において、上記金型は柱状体であり、上記電極は上記柱状体の外表面に形成されているものであることを特徴とする。この発明によれば、電極が柱状体とされた金型の外表面に形成するように構成されたものにおいて、上記第１又は第２発明の作用が得られる。
【００１２】
請求項４に記載の発明は、請求項１又は２のいずれかに記載の溝加工装置において、上記金型は円筒体であり、上記電極は上記円筒体の内表面に形成されているものであることを特徴とする。この発明によれば、電極が円筒体とされた金型の内表面に形成するように構成されたものにおいて、上記第１又は第２発明の作用が得られる。
【００１３】
請求項５に記載の発明は、請求項１〜４のいずれかに記載の動圧溝加工装置において、上記被加工物には、動圧溝が形成される一対の被加工面が軸芯方向に離れて設けられており、上記電極を一方の被加工面に対向させるとともに、上記テーパ部を他方の被加工面に対向させ、上記保持部材に保持された上記少なくとも３個の球体を上記テーパ部の側面と上記他方の被加工面とに当接させるように構成されていることを特徴とする。この発明によれば、被加工物に一対の被加工面が軸芯方向に離れて設けられている場合には、電極を一方の被加工面に対向させるとともに、上記テーパ部を他方の被加工面に対向させ、上記保持部材に保持された上記少なくとも３個の球体を上記テーパ部の側面と上記他方の被加工面とに当接させるようにすれば、上記一対の被加工面に動圧溝を加工することができる。
【００１４】
その場合に、請求項６に記載の発明のように、上記電極を上記一方の被加工面に対向させて溝加工を行う第１の工程と、上記第１の工程に対して反転状態で上記電極を上記他方の被加工面に対向させて溝加工を行う第２の工程とにより、上記一対の被加工面に対する溝加工を行うようにしてもよい。
【００１５】
【発明の実施の形態】
本動圧溝加工装置１は、真鍮もしくはステンレス等からなるスリーブＳを加工する電解加工機１０と、この電解加工機１０に供給する電解液Ｌを貯留する電解液供給タンク５０と、この電解液供給タンク５０から電解液Ｌを汲み上げて電解加工機１０に供給する電解液供給ポンプ６０と、電解加工機１０から排出された電解液Ｌを一時的に貯留する電解液再生タンク７０とを備える。上記電解液Ｌは、例えば、硝酸ナトリウムＮａＮＯ₃を３０重量％含有するものである。
【００１６】
図１に示すように、電解加工機１０は、固設された第１加工ユニット２０と、この第１加工ユニット２０の配設位置の上方に設けられた第２加工ユニット３０と、この第２加工ユニット３０を昇降駆動して第１加工ユニット２０に対して近接離反させる駆動手段としてのエアシリンダ１１と、第１、第２加工ユニット２０，３０及びエアシリンダ１１を支持する固定台１２とを有し、第２加工ユニット３０が第１加工ユニット２０に最も近接したときに、第１加工ユニット２０上に載置された円筒状のスリーブＳの軸芯位置と第１加工ユニット２０に設けられた金型電極としての円柱状の嵌合部材の軸芯位置とを一致させ（以下、調芯という）て、スリーブＳの内周面に、例えば深さ１０ミクロンのへリングボーン状の動圧溝を形成する。本発明の動圧溝加工装置１は、円筒状のスリーブＳの軸芯位置と円柱状の嵌合部材の軸芯位置とを調芯する機構に特徴がある。
【００１７】
第１加工ユニット２０は、電源８０の負端子８１と接続されている。また、第１加工ユニット２０には、電解液供給タンク５０に貯留された電解液Ｌが電解液供給ポンプ６０により供給されるようになっている。なお、電解液供給ポンプ６０により供給される電解液Ｌの一部は電解液供給タンク７０に戻されるとともに、第１加工ユニット２０から流出した電解液Ｌは、固形物除去フィルタ７１を介して不要物が除去された状態で電解液再生タンク７０に戻された後、フィルタ用ポンプ７２によりこの電解液再生タンク７０から汲み上げられフィルタ７３を介して電解液供給タンク５０に戻される。
【００１８】
第２加工ユニット３０は、電気伝導性を有する材質からなる円筒状の電極接続具３１を有し、この電極接続具３１はエアシリンダ１１のロッド１１ａ下端に取付部材３０１を介して取付けられている。電極接続具３１は、ＦＥＴ（Field Effect Transistor）等のスイッチ素子ＳＷを介して電源８０の正端子８２と接続されている。
【００１９】
図２に示すように、電極接続具３１の下端部には、中央部に孔を有する円盤状の第１プレート部材３２が取付けられている。このプレート部材３２は、電気伝導性を有する材質からなり、電極接続具３１を電源８０の正端子８２に接続することで、第２加工ユニット３０を下降させ電極接続具３１をスリーブＳ上端面に当接させたときに、上記スリーブＳが正極となるように構成されている。
【００２０】
第１プレート部材３２には、電解液Ｌを外部へ排出するための電解液排出路３２ａが設けられている。
【００２１】
電極接続具３１は、軸芯方向に延びる貫通孔３１ａを有し、この貫通孔３１ａの下側部分には、後述する調芯用押え部材３３が遊嵌されているとともに、貫通孔３１ａの上側部分がネジ部３１ｂとされ、このネジ部３１ｂに調整ネジ３４が螺合されている。調整ネジ３４と調芯用押え部材３３との間には、この調芯用押え部材３３を下方へ付勢するためのスプリング３５が介設されており、貫通孔３１ａに対する調整ネジ３１ｂの相対位置を調整することで、調芯用押え部材３３に作用する付勢力が調節されるようになっている。
【００２２】
第１加工ユニット２０は、固定台１２に固設されたベース部材２１と、このベース部材２１の周囲に取付けられた円筒状のカバー部材２２とを有し、このカバー部材２２とベース部材２１とにより凹部Ｈが形成されている。そして、この凹部Ｈに第１プレート部材３２の電解液排出路３２ａからの電解液Ｌが排出されるようになっている。また、カバー部材２２の適所には、電解液排出路２２ａが設けられており、この凹部Ｈに排出された電解液Ｌがこの電解液排出路２２ａを通って電解液再生タンク７０に排出されるようになっている。その際、ベース部材２１とカバー部材２２との隙間から外部へ電解液Ｌが漏出するのを防止すべく、シール手段としてのＯリング２３が設けられている。
【００２３】
ベース部材２１は、その上面中央部分において上方に突出する突出部２１ａを有し、この突出部２１ａに設けられた取付孔２１ａ’に後述する加工機構２４が取付けられている。
【００２４】
加工機構２４は、上記取付孔２１ａ’に嵌合固定される基部材２５と、この基部材２５の上面に設けられ、スリーブＳに内嵌する上記金型電極としての円柱状の嵌合部材２６とを有する。突出部２１ａの開口部分には、電気絶縁性の材質からなる基部カバー部材２８が取付けられており、嵌合部材２６の上部が、基部カバー部材２８の中央部に設けられた孔２８ａを介して突出部２１ａの開口部から突出するようになっている。そして、スリーブＳを加工する際には、この突出する上部にスリーブＳを嵌合し仮保持した状態で、第１加工ユニット２０の基部カバー部材２８上にセットされることになる。
【００２５】
ベース部材２１には、突出部２１ａの底部からさらに奥側へ延び、突出部２１ａの取付孔２１ａ’より小径の第１電解液供給路２１ｂと、この供給路２１ｂに略垂直に交差する第２電解液供給路２１ｃとが設けられており、電解液供給タンク５０から供給された電解液Ｌは、第２電解液供給路２１ｃを通って第１電解液供給路２１ｂに流入するようになっている。また、基部材２５には、複数の貫通孔２５ａが設けられているとともに、基部材２５の上面と基部カバー部材２８の孔２８ａの内周面との間には所定の間隙Ｐが形成され、第１電解液供給路２１ｂに流入した電解液Ｌは、上記貫通孔２５ａ及び間隙Ｐを介して、嵌合部材２６とスリーブＳとの間隙に供給されるようになっている。
【００２６】
電源８０の負端子８１は、第１加工ユニット２０の嵌合部材２６に接続されており、これにより、嵌合部材２６は負極となる。また、図３に示すように、スリーブＳに嵌合する嵌合部材２６の上部は、周面にへリングボーン状の電極が形成された電極形成部２６ａとされており、この電極形成部２６ａとスリーブＳの被加工面とが電解液Ｌを介して対向するようになっている。これにより、電源８０がＯＮされると、電極形成部２６ａとスリーブＳの被加工面との間で通電することになる。なお、本実施形態においては、上記電源８０は、１０（Ａ）の電流を電圧１０（Ｖ）で通電させるとともに、この通電時間は、上記スイッチ素子ＳＷにより１回の加工につき１〜３秒間に設定されている。なお、上記電流値、電圧値及び通電時間は、上記数値に限らず適宜変更可能である。
【００２７】
次に、本発明の特徴部分である調芯機構について説明する。
【００２８】
調芯用押え部材３３の下端部は、上側部分に比して小さい径とされているとともに、図４に示すように、横断面視で１２０度間隔で切欠き部３３ａが設けられている。また、この調芯用押え部材３３には後述のボール保持部材３６が嵌合固定され、このボール保持部材３６と上記調芯用押え部材３３との間に、電気絶縁性を有する材質で構成された球状の調芯用ボール部材３７が複数配設されている。
【００２９】
ボール保持部材３６は、後述の調芯部材２７が挿通する挿通孔３６ａと、調芯用ボール部材３７を径方向に逸脱しない程度に移動可能とする複数のボール保持穴部３６ｂと、各ボール保持穴部３６ｂ間に立設され、上記調芯用押え部材３３の切欠き部３３ａに嵌入する壁部３６ｃとを有する。
【００３０】
嵌合部材２６の上端面には、テーパ面２７ａを有するペン先形状の調芯部材２７が取付けられている。
【００３１】
次に、本発明の作用について説明する。
【００３２】
上記電極接続具３１が下降すると、調芯部材２７がボール保持部材３６の挿通孔３６ａに嵌合し、図５の鎖線で示すように、上記調芯用ボール部材３７は、調芯部材２７のテーパ面２７ａに当接する。そして、第２加工ユニット３０の降下に伴って、そのテーパ面２７ａにより調芯用ボール部材３７が径方向外側に押され、スリーブＳの内周面にも当接することになる。その後、その状態からさらに所定の長さだけ第２加工ユニット３０が降下することにより、調芯用ボール部材３７が、上記テーパ面２７ａ及びスリーブＳの内周面に所定の押付力で押し付けられて、スリーブＳと嵌合部材２６とが固定されることになる。
【００３３】
これにより、図６に示すように、調芯部材２７の軸芯位置Ｇから各調芯用ボール部材３７の中芯Ｏ₁〜Ｏ₃までの距離Ｒ₁〜Ｒ₃がすべて等しくなるから、スリーブＳの軸芯位置と嵌合部材２６の軸芯位置とが一致することになる。
【００３４】
以上の構成により、スリーブＳの内周面と嵌合部材２６の電極形成部２６ａとが、どの部位においても同一の間隙で対向した状態で動圧溝形成処理を行うことができる。その結果、動圧溝の深さや幅にばらつきが発生するのを防止することができる。また、スリーブＳをセットする際には、嵌合部材２６にスリーブＳを嵌めるだけであり、また、加工されたスリーブＳを取り出す際には、第２加工ユニットを元の上昇位置に戻すだけでよいから、スリーブＳの着脱が容易である。
【００３５】
また、調芯用ボール部材３７を電気絶縁性を有する材質で構成したから、調芯部材２７とスリーブＳの内周面との間で調芯用ボール部材３７を介して通電してしまうのを防止することができる。
【００３６】
なお、上記実施形態においては、テーパ面が嵌合部材２６に１箇所設けられているが、図７に示すように、スリーブＳの内周面の２つの部位に動圧溝を形成する場合には、嵌合部材２６に２つのテーパ面（第１、第２テーパ面２６Ａ，２６Ｂ）を設け、テーパ面２６ＡとスリーブＳの内周面とに調芯用ボール部材３７’を、テーパ面２６ＢとスリーブＳの内周面とに調芯用ボール部材３７”をそれぞれ押し付けて調芯を行うようにすれば、被加工面Ｓ_a，Ｓ_bが離間していても、どちらの部分においても一定の間隙で電極形成部２６ａ’，２６ａ”に対向配置させることができる。また、上記第１実施形態のように被加工面が１箇所であっても、このように軸芯方向に２箇所の調芯機構を設けることで、さらに高い精度で両軸芯を一致させることができる。
【００３７】
また、シャフトＢの周面に所定の動圧溝を形成する場合には、図８に示すように、円筒状の電極５０の内部にシャフトＢを嵌挿させ、シャフトＢと電極５０との間で通電させることになるが、この場合、電極５０の内周面にテーパ面５０ａを設け、上記第１実施形態と同様に、シャフトＢの外周面と上記電極５０のテーパ面５０ａに調芯用ボール部材６０を所定の押付力で押し付けるようにすれば、シャフトＢの軸芯位置と電極５０の軸芯位置とを一致させることができる。
【００３８】
さらに、本発明のようにスリーブＳやシャフトＢ等の円周面に動圧溝を形成する場合に限らず、被加工物の被加工面が例えば角周面のように、軸芯位置から見て均一な周面を有する被加工物であれば本発明は採用可能である。また、形成する溝は上記のような動圧溝に限らず、他種の溝であってもよい。
【００３９】
また、上記実施形態においては、各調芯用ボール部材６０を横断面視で１２０度間隔で配設しているが、これに限らず、図６に示すように、軸芯Ｇと各調芯用ボール部材６０の中芯Ｏ₁〜Ｏ₃とで構成される中芯角θ₁〜θ₃が、いずれも１８０°超えない角度となるように調芯用ボール部材６０を配設すればよい。
【００４０】
【発明の効果】
請求項１に記載の発明によれば、金型の円周状周面から上記被加工物の表面までの距離が等しくなるように、被加工物の軸芯位置と電極の軸芯位置とを一致させたから、被加工物と金型とが全周にわたって一定の間隙を介して対向した状態で被加工物を加工することができ、形成する溝の深さや幅にばらつきが発生するのを防止することができる。
【００４１】
請求項２に記載の発明によれば、テーパ面と被加工物との間に球部材を介設してもこの部分では通電しないから、テーパ面と被加工物との間に無駄な通電が発生するのを回避することができる。
【００４２】
請求項３に記載の発明によれば、より確実に被加工物の軸芯位置を金型の軸芯位置に一致させることができる。
【００４３】
請求項４に記載の発明によれば、電極が柱状体とされた金型の外表面に形成するように構成されたものにおいて、上記第１〜第３発明の作用が得られる。
【００４４】
請求項５に記載の発明によれば、電極が円筒体とされた金型の内表面に形成するように構成されたものにおいて、上記第１〜第３発明の作用が得られる。
【００４５】
請求項６に記載の発明によれば、被加工物に一対の被加工面が軸芯方向に離れて設けられている場合には、電極を一方の被加工面に対向させるとともに、上記テーパ部を他方の被加工面に対向させ、上記保持部材に保持された上記少なくとも３個の球体を上記テーパ部の側面と上記他方の被加工面とに当接させるようにするようにしたから、上記一対の被加工面に動圧溝を加工することができる。
【００４６】
その場合に、請求項７に記載の発明のように、上記電極を上記一方の被加工面に対向させて溝加工を行う第１の工程と、上記第１の工程に対して反転状態で上記電極を上記他方の被加工面に対向させて溝加工を行う第２の工程を行うことで、上記一対の被加工面に動圧溝を加工することができる。
【図面の簡単な説明】
【図１】本発明に係る溝加工装置の一実施形態の全体構成図である。
【図２】第１、第２加工ユニットの拡大断面図である。
【図３】調芯部分の拡大断面図である。
【図４】調芯部分の構造を示す説明図である。
【図５】本発明の作用を示す説明図である。
【図６】同じく本発明の作用を示す説明図である。
【図７】調芯部分を２つ設けたときの断面図である。
【図８】本発明の他の実施形態を示す調芯部分の概略図である。
【符号の説明】
１溝加工装置
２０第１加工ユニット
２６嵌合部材
２６ａ電極形成部
２７調芯部材
２７ａテーパ面
３０第２加工ユニット
３１電極接続具
３３調芯用押え部材
３３ａ切欠き部
３６ボール保持部材
３６ａ挿通孔
３６ｂボール保持穴部
３６ｃ壁部
３７調芯用ボール部材
Ｓスリーブ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a dynamic pressure groove processing apparatus for forming dynamic pressure grooves on an inner peripheral surface of a sleeve, an outer peripheral surface of a shaft (shaft body), and the like.
[0002]
[Prior art]
Conventionally, for example, a rotary bearing such as a motor for rotationally driving a recording medium such as a hard disk, a dynamic pressure bearing using a fluid is sometimes used, and an inner peripheral surface of a sleeve provided in the dynamic pressure bearing portion In addition, a dynamic pressure groove having a predetermined shape is formed on the outer peripheral surface of the shaft.
[0003]
As a method of forming such a dynamic pressure groove in a bearing material such as the sleeve, for example, an electrolytic processing method as disclosed in JP-A-10-86020 may be employed.
[0004]
In this electrolytic processing method, a mold having an electrode having a predetermined shape and a surface to be processed of a bearing material are arranged to face each other with a predetermined gap therebetween, and a predetermined electrolytic solution is allowed to flow through the gap. By energizing between the work surface of the bearing material, a groove (dynamic pressure groove) corresponding to the shape of the electrode is formed on the work surface of the bearing material. When the dynamic pressure groove is formed on the inner peripheral surface of the sleeve, a die having an outer peripheral surface facing the inner peripheral surface and having an electrode of a predetermined shape formed on the outer peripheral surface is used. When a dynamic pressure groove is formed on the outer peripheral surface, a mold having an inner peripheral surface facing the outer peripheral surface and having electrodes of a predetermined shape formed on the inner peripheral surface is used.
[0005]
[Problems to be solved by the invention]
By the way, when machining the bearing material as described above, if the gap between the bearing material and the mold is not constant over the entire circumference, the energization amount will vary depending on each part of the electrode and the bearing material, As a result, there arises a problem that variation occurs in the depth and width of the dynamic pressure groove to be formed.
[0006]
The present invention has been made in view of the above, and when the dynamic pressure grooves that mainly constitute the dynamic pressure bearing portion are formed in the bearing material, variations in the depth and width of the dynamic pressure grooves to be formed occur. The purpose is to prevent.
[0007]
[Means for Solving the Problems]
According to the first aspect of the present invention, the circumferential circumferential surface of the workpiece is opposed to the circumferential surface of a mold in which electrodes having a predetermined shape are formed on the circumferential circumferential surface, and the electrode, the workpiece, In a state where the gap is filled with the electrolyte solution, a current is applied between the electrode and the workpiece, and a dynamic pressure groove corresponding to the electrode is formed on the circumferential surface of the workpiece. The pressure groove processing apparatus includes an alignment mechanism portion that aligns the electrode and the workpiece, and the alignment mechanism portion is provided in a part of the mold and is arranged concentrically with the electrode. A conical tapered portion, at least three spheres having the same diameter, each sphere being brought into contact with a side surface of the tapered portion and a circumferential circumferential surface of the workpiece, and the taper Holding in a predetermined position in the circumferential direction so that the gap between the side surface of the part and the circumferential circumferential surface of the workpiece is equal in the circumferential direction. Comprising a timber, a, it is between the tapered portion and the workpiece are each sphere interposed, each sphere is characterized in that it is intended to indicate an electrical insulation.
[0008]
According to this invention, the conical taper portion provided in a part of the mold and extending in the axial direction, at least three spheres having the same diameter, and each sphere is connected to the side surface of the taper portion and the cover. In order to contact the surface of the workpiece, a centering mechanism portion provided with a holding member that holds each of the workpiece in a predetermined position in the circumferential direction is provided, so that from the circumferential circumferential surface of the mold to the surface of the workpiece The distance becomes equal, and the axial center position of the workpiece matches the axial center position of the electrode. Therefore, the workpiece is processed in a state where the workpiece and the mold face each other with a certain gap over the entire circumference, and variation in the depth and width of the groove to be formed is prevented. be able to.
[0010]
According to a second aspect of the invention, the groove processing apparatus according to claim 1, said alignment mechanism is characterized in that in the axial direction of the mold are provided at least two. According to the present invention, the axial center position of the workpiece can be more reliably matched with the axial center position of the mold.
[0011]
According to a third aspect of the present invention, in the groove processing apparatus according to the first or second aspect , the mold is a columnar body, and the electrode is formed on an outer surface of the columnar body. It is characterized by being. According to the present invention, in the structure in which the electrode is formed on the outer surface of the mold having a columnar body, the effect of the first or second invention can be obtained.
[0012]
According to a fourth aspect of the present invention, in the grooving apparatus according to the first or second aspect , the mold is a cylindrical body, and the electrode is formed on an inner surface of the cylindrical body. It is characterized by being. According to the present invention, in the structure in which the electrode is formed on the inner surface of the cylindrical mold, the effect of the first or second invention can be obtained.
[0013]
According to a fifth aspect of the present invention, in the dynamic pressure groove machining apparatus according to any one of the first to fourth aspects, the workpiece has a pair of work surfaces on which the dynamic pressure grooves are formed in an axial direction. The at least three spheres held by the holding member with the tapered portion facing the other processing surface and the taper portion facing the other processing surface. It is comprised so that it may contact | abut to the side surface of a part, and the said other to-be-processed surface. According to the present invention, when the workpiece is provided with a pair of workpiece surfaces that are separated from each other in the axial direction, the electrode is opposed to one of the workpiece surfaces and the tapered portion is disposed on the other workpiece. If the at least three spheres held on the holding member are brought into contact with the side surface of the tapered portion and the other processed surface, the dynamic pressure is applied to the pair of processed surfaces. Grooves can be processed.
[0014]
In that case, as in the invention described in claim 6 , the first step of performing grooving with the electrode opposed to the one surface to be processed, and the inversion state with respect to the first step You may make it perform the groove process with respect to a pair of said to-be-processed surface by the 2nd process of making an electrode oppose the said other to-be-processed surface, and performing a groove process.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
The dynamic pressure groove processing apparatus 1 includes an electrolytic processing machine 10 that processes a sleeve S made of brass or stainless steel, an electrolytic solution supply tank 50 that stores an electrolytic solution L to be supplied to the electrolytic processing machine 10, and the electrolytic solution. An electrolytic solution supply pump 60 that pumps the electrolytic solution L from the supply tank 50 and supplies the electrolytic solution L to the electrolytic processing machine 10 and an electrolytic solution regeneration tank 70 that temporarily stores the electrolytic solution L discharged from the electrolytic processing machine 10 are provided. The electrolyte L contains, for example, 30% by weight of sodium nitrate NaNO ₃ .
[0016]
As shown in FIG. 1, the electrolytic processing machine 10 includes a fixed first processing unit 20, a second processing unit 30 provided above the position where the first processing unit 20 is disposed, and the second processing unit 20. An air cylinder 11 as drive means for moving the machining unit 30 up and down to approach and move away from the first machining unit 20, and a fixed base 12 that supports the first and second machining units 20, 30 and the air cylinder 11. And when the second processing unit 30 is closest to the first processing unit 20, the axial position of the cylindrical sleeve S placed on the first processing unit 20 and the first processing unit 20 are provided. For example, a herringbone-like dynamic pressure having a depth of 10 microns is formed on the inner peripheral surface of the sleeve S by matching the axial center position of the cylindrical fitting member as the mold electrode (hereinafter referred to as alignment). Grooves are formed. The dynamic pressure groove processing apparatus 1 of the present invention is characterized by a mechanism for aligning the axial center position of the cylindrical sleeve S and the axial center position of the columnar fitting member.
[0017]
The first processing unit 20 is connected to the negative terminal 81 of the power supply 80. In addition, the first processing unit 20 is supplied with the electrolyte L stored in the electrolyte supply tank 50 by the electrolyte supply pump 60. A part of the electrolytic solution L supplied by the electrolytic solution supply pump 60 is returned to the electrolytic solution supply tank 70, and the electrolytic solution L flowing out from the first processing unit 20 is not necessary via the solid matter removing filter 71. After being returned to the electrolyte regeneration tank 70 in a state where the substances are removed, it is pumped up from the electrolyte regeneration tank 70 by the filter pump 72 and returned to the electrolyte supply tank 50 through the filter 73.
[0018]
The second processing unit 30 has a cylindrical electrode connector 31 made of a material having electrical conductivity, and this electrode connector 31 is attached to the lower end of the rod 11 a of the air cylinder 11 via an attachment member 301. . The electrode connector 31 is connected to the positive terminal 82 of the power supply 80 via a switch element SW such as an FET (Field Effect Transistor).
[0019]
As shown in FIG. 2, a disk-shaped first plate member 32 having a hole in the center is attached to the lower end of the electrode connector 31. The plate member 32 is made of a material having electrical conductivity. By connecting the electrode connector 31 to the positive terminal 82 of the power source 80, the second processing unit 30 is lowered to place the electrode connector 31 on the upper end surface of the sleeve S. The sleeve S is configured to be a positive electrode when brought into contact.
[0020]
The first plate member 32 is provided with an electrolyte discharge path 32a for discharging the electrolyte L to the outside.
[0021]
The electrode connector 31 has a through hole 31a extending in the axial direction, and an alignment pressing member 33 (described later) is loosely fitted to the lower portion of the through hole 31a, and the upper side of the through hole 31a. The portion is a screw portion 31b, and an adjustment screw 34 is screwed into the screw portion 31b. A spring 35 is interposed between the adjustment screw 34 and the alignment pressing member 33 to bias the alignment pressing member 33 downward, and the relative position of the adjustment screw 31b with respect to the through hole 31a. By adjusting the urging force, the urging force acting on the alignment pressing member 33 is adjusted.
[0022]
The first processing unit 20 includes a base member 21 fixed to the fixed base 12 and a cylindrical cover member 22 attached around the base member 21, and the cover member 22, the base member 21, Thus, a recess H is formed. Then, the electrolytic solution L from the electrolytic solution discharge path 32a of the first plate member 32 is discharged into the recess H. Further, an electrolyte solution discharge path 22a is provided at an appropriate position of the cover member 22, and the electrolyte solution L discharged to the concave portion H is discharged to the electrolyte regeneration tank 70 through the electrolyte solution discharge path 22a. It is like that. At this time, an O-ring 23 as a sealing means is provided to prevent the electrolyte L from leaking outside through the gap between the base member 21 and the cover member 22.
[0023]
The base member 21 has a protruding portion 21a that protrudes upward at the center portion of the upper surface, and a processing mechanism 24 described later is attached to an attachment hole 21a ′ provided in the protruding portion 21a.
[0024]
The processing mechanism 24 includes a base member 25 that is fitted and fixed in the mounting hole 21a ′, and a columnar fitting member 26 that is provided on the upper surface of the base member 25 and that is fitted in the sleeve S as the mold electrode. And have. A base cover member 28 made of an electrically insulating material is attached to the opening portion of the protruding portion 21 a, and the upper portion of the fitting member 26 is inserted through a hole 28 a provided in the central portion of the base cover member 28. It protrudes from the opening part of the protrusion part 21a. When the sleeve S is processed, the sleeve S is fitted onto the protruding upper portion and temporarily held, and is set on the base cover member 28 of the first processing unit 20.
[0025]
The base member 21 has a first electrolyte solution supply path 21b that extends further from the bottom of the protrusion 21a and has a smaller diameter than the attachment hole 21a ′ of the protrusion 21a, and a second that intersects the supply path 21b substantially perpendicularly. The electrolyte solution supply path 21c is provided, and the electrolyte solution L supplied from the electrolyte solution supply tank 50 flows into the first electrolyte solution supply path 21b through the second electrolyte solution supply path 21c. Yes. The base member 25 is provided with a plurality of through holes 25a, and a predetermined gap P is formed between the upper surface of the base member 25 and the inner peripheral surface of the hole 28a of the base cover member 28 . The electrolyte L flowing into the first electrolyte supply path 21b is supplied to the gap between the fitting member 26 and the sleeve S through the through hole 25a and the gap P.
[0026]
The negative terminal 81 of the power source 80 is connected to the fitting member 26 of the first processing unit 20, whereby the fitting member 26 becomes a negative electrode. Further, as shown in FIG. 3, the upper portion of the fitting member 26 that fits into the sleeve S is an electrode forming portion 26a in which a herringbone electrode is formed on the peripheral surface, and this electrode forming portion 26a. And the work surface of the sleeve S are opposed to each other with the electrolytic solution L interposed therebetween. As a result, when the power supply 80 is turned on, current is supplied between the electrode forming portion 26a and the work surface of the sleeve S. In the present embodiment, the power supply 80 energizes a current of 10 (A) at a voltage of 10 (V), and this energization time is 1 to 3 seconds per process by the switch element SW. Is set. The current value, voltage value, and energization time are not limited to the above numerical values and can be changed as appropriate.
[0027]
Next, the alignment mechanism which is a characteristic part of the present invention will be described.
[0028]
The lower end portion of the alignment pressing member 33 has a diameter smaller than that of the upper portion, and as shown in FIG. 4, notched portions 33a are provided at intervals of 120 degrees in a cross sectional view. Further, a ball holding member 36 to be described later is fitted and fixed to the centering pressing member 33, and the ball holding member 36 and the centering pressing member 33 are made of a material having electrical insulation. A plurality of spherical alignment ball members 37 are disposed.
[0029]
The ball holding member 36 includes an insertion hole 36a through which an alignment member 27 (to be described later) is inserted, a plurality of ball holding holes 36b that allow the alignment ball member 37 to move within a radial direction, and each ball holding It has a wall part 36c which is erected between the hole parts 36b and fits into the notch part 33a of the alignment pressing member 33.
[0030]
A nib-shaped alignment member 27 having a tapered surface 27 a is attached to the upper end surface of the fitting member 26.
[0031]
Next, the operation of the present invention will be described.
[0032]
When the electrode connector 31 is lowered, the alignment member 27 is fitted into the insertion hole 36a of the ball holding member 36, and the alignment ball member 37 is connected to the alignment member 27 as shown by a chain line in FIG. It contacts the tapered surface 27a. As the second machining unit 30 is lowered, the alignment ball member 37 is pushed radially outward by the taper surface 27 a and also comes into contact with the inner peripheral surface of the sleeve S. Thereafter, when the second processing unit 30 is further lowered from the state by a predetermined length, the alignment ball member 37 is pressed against the tapered surface 27a and the inner peripheral surface of the sleeve S with a predetermined pressing force. The sleeve S and the fitting member 26 are fixed.
[0033]
As a result, as shown in FIG. 6, since the distances R _{1 to} R ₃ from the axial center position G of the alignment member 27 to the center O _{1 to} O ₃ of the alignment ball members 37 are all equal, The axial center position of S and the axial center position of the fitting member 26 coincide.
[0034]
With the above configuration, the dynamic pressure groove forming process can be performed with the inner peripheral surface of the sleeve S and the electrode forming portion 26a of the fitting member 26 facing each other at the same gap. As a result, it is possible to prevent variations in the depth and width of the dynamic pressure grooves. Further, when setting the sleeve S, it is only necessary to fit the sleeve S into the fitting member 26, and when taking out the processed sleeve S, it is only necessary to return the second processing unit to the original raised position. Since it is good, the sleeve S can be easily attached and detached.
[0035]
In addition, since the alignment ball member 37 is made of a material having electrical insulation, it is energized between the alignment member 27 and the inner peripheral surface of the sleeve S via the alignment ball member 37. Can be prevented.
[0036]
In the above-described embodiment, the tapered surface is provided at one place on the fitting member 26. However, as shown in FIG. 7, when the dynamic pressure grooves are formed at two portions on the inner peripheral surface of the sleeve S. Is provided with two tapered surfaces (first and second tapered surfaces 26A, 26B) on the fitting member 26, an alignment ball member 37 'is provided on the tapered surface 26A and the inner peripheral surface of the sleeve S, and the tapered surface 26B. If the centering ball member 37 "is pressed against the inner peripheral surface of the sleeve S and the centering is performed, the surface to be processed S _a , S _b will be constant in either part even if they are separated from each other The electrode forming portions 26a ′ and 26a ″ can be arranged to face each other with a gap of. Moreover, even if there is only one surface to be processed as in the first embodiment, by providing two alignment mechanisms in the axial direction in this way, both axial centers can be matched with higher accuracy. Can do.
[0037]
When a predetermined dynamic pressure groove is formed on the peripheral surface of the shaft B, as shown in FIG. 8, the shaft B is fitted into the cylindrical electrode 50, and the shaft B and the electrode 50 are interposed. In this case, a tapered surface 50a is provided on the inner peripheral surface of the electrode 50, and the outer peripheral surface of the shaft B and the tapered surface 50a of the electrode 50 are used for alignment as in the first embodiment. If the ball member 60 is pressed with a predetermined pressing force, the axial center position of the shaft B and the axial center position of the electrode 50 can be matched.
[0038]
Furthermore, the present invention is not limited to the case where the dynamic pressure grooves are formed on the circumferential surfaces of the sleeve S and the shaft B as in the present invention. The present invention can be adopted as long as the workpiece has a uniform peripheral surface. Further, the grooves to be formed are not limited to the dynamic pressure grooves as described above, but may be other types of grooves.
[0039]
In the above embodiment, the alignment ball members 60 are arranged at intervals of 120 degrees in a cross-sectional view. However, the present invention is not limited to this, and as shown in FIG. interliner O ₁ ~ O ₃ and in the core angle theta ₁ through? ₃ composed of use ball member 60 may be disposed in alignment ball member 60 as both a 180 ° not exceeding an angle .
[0040]
【The invention's effect】
According to the first aspect of the present invention, the axial position of the workpiece and the axial position of the electrode are set such that the distance from the circumferential circumferential surface of the mold to the surface of the workpiece is equal. Since they match, the workpiece can be processed with the workpiece and the mold facing each other with a certain gap over the entire circumference, preventing variations in the depth and width of the grooves to be formed. can do.
[0041]
According to the second aspect of the present invention, even if a ball member is interposed between the tapered surface and the work piece, no current is passed through this portion. It can be avoided.
[0042]
According to the third aspect of the present invention, the axial center position of the workpiece can be more reliably matched with the axial center position of the mold.
[0043]
According to the fourth aspect of the present invention, in the configuration in which the electrode is formed on the outer surface of the columnar body, the effects of the first to third aspects of the invention can be obtained.
[0044]
According to the fifth aspect of the present invention, in the structure in which the electrode is formed on the inner surface of the cylindrical mold, the effects of the first to third aspects of the invention can be obtained.
[0045]
According to the invention described in claim 6, when the workpiece is provided with a pair of workpiece surfaces separated in the axial direction, the electrode is opposed to one of the workpiece surfaces and the tapered portion is provided. Is opposed to the other processed surface, and the at least three spheres held by the holding member are brought into contact with the side surface of the tapered portion and the other processed surface. The dynamic pressure grooves can be machined on the pair of work surfaces.
[0046]
In that case, as in the invention described in claim 7, the first step of performing groove processing with the electrode facing the one surface to be processed, and the inversion state with respect to the first step A dynamic pressure groove can be processed in the pair of processed surfaces by performing the second step of performing the groove processing with the electrode facing the other processed surface.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of an embodiment of a groove processing apparatus according to the present invention.
FIG. 2 is an enlarged sectional view of first and second processing units.
FIG. 3 is an enlarged cross-sectional view of an alignment portion.
FIG. 4 is an explanatory view showing a structure of an alignment portion.
FIG. 5 is an explanatory diagram showing the operation of the present invention.
FIG. 6 is an explanatory view showing the operation of the present invention.
FIG. 7 is a cross-sectional view when two alignment portions are provided.
FIG. 8 is a schematic view of an alignment portion showing another embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Groove processing apparatus 20 1st process unit 26 Fitting member 26a Electrode formation part 27 Alignment member 27a Tapered surface 30 2nd process unit 31 Electrode connection tool 33 Alignment pressing member 33a Notch part 36 Ball holding member 36a Insertion hole 36b Ball holding hole portion 36c Wall portion 37 Ball member S for alignment S sleeve

Claims

A state in which the circumferential circumferential surface of the workpiece is opposed to the circumferential surface of a mold having electrodes of a predetermined shape formed on the circumferential circumferential surface, and a gap between the electrode and the workpiece is filled with an electrolytic solution In the dynamic pressure groove processing apparatus for forming a dynamic pressure groove corresponding to the electrode on a circumferential circumferential surface of the workpiece by energizing between the electrode and the workpiece, A centering mechanism that performs centering with the workpiece, and the centering mechanism is provided in a part of the mold, and a conical taper disposed concentrically with the electrode; At least three spheres having the same diameter, and each sphere is brought into contact with the side surface of the tapered portion and the circumferential circumferential surface of the workpiece, and the side surface of the tapered portion and the workpiece A holding member for holding each circumferential circumferential surface at a predetermined position in the circumferential direction in order to make the gap with the circumferential circumferential surface equal to the circumferential direction. Between the parts and the workpiece are each sphere interposed, each sphere dynamic pressure groove processing apparatus is characterized in that shows the electrical insulating properties.

It said alignment mechanism includes dynamic pressure groove processing apparatus according to claim 1, wherein the provided at least two in the axial direction of the mold.

It said mold is a columnar body, the electrode is dynamic pressure groove processing apparatus according to claim 1 or 2, characterized in that formed on the outer surface of the columnar body.

It said mold has a cylindrical body, the electrode is dynamic pressure groove processing apparatus according to claim 1 or 2, characterized in that formed on the inner surface of the cylindrical body.

The workpiece is provided with a pair of machining surfaces in which a dynamic pressure groove is formed so as to be separated from each other in the axial direction, the electrode is opposed to one machining surface, and the tapered portion is arranged on the other workpiece. The structure is characterized in that the at least three spheres held by the holding member are brought into contact with a side surface of the tapered portion and the other processed surface so as to face the processing surface. Item 5. The dynamic pressure groove processing apparatus according to any one of Items 1 to 4 .

A first step of performing groove processing with the electrode opposed to the one processing surface; and a groove processing with the electrode opposed to the other processing surface in an inverted state with respect to the first step. 6. The hydrodynamic groove processing apparatus according to claim 5 , wherein the second pressure step is configured to perform groove processing on the pair of processing surfaces.