JP3827554B2

JP3827554B2 - Guide device using ultrasonic motor as drive source of movable body

Info

Publication number: JP3827554B2
Application number: JP2001330084A
Authority: JP
Inventors: 康司加藤; 幸志足立; 裕作石峯
Original assignee: Kyocera Corp
Current assignee: Kyocera Corp
Priority date: 2000-11-30
Filing date: 2001-10-29
Publication date: 2006-09-27
Anticipated expiration: 2021-10-29
Also published as: JP2002233172A

Description

【０００１】
【発明の属する技術分野】
本発明は、直線運動や回転運動する可動体を超音波モータにて駆動させる案内装置に関するものであり、特に精密加工機械、精密測定装置、半導体製造装置に用いられる案内装置として好適なものである。
【０００２】
【従来の技術及び発明が解決しようとする課題】
超音波モータは、最小振幅がナノオーダーと小さく、高分解能の位置決めが可能であり、しかも摩擦駆動であるために駆動力が大きいといった特徴を有するため、これまでカメラのレンズズーム機構や腕時計のバイブレーションアラームなど回転運動系への実用化が行われており、最近では直線運動系への適用が試みられている。
【０００３】
図８に超音波モータを可動体の駆動源とする従来の案内装置の一例を示すように、この案内装置は、ベース盤６１上にクロスローラガイドの如き一対のガイド部材６２を備え、これらのガイド部材６２によって可動体としてのステージ６３を直線的に案内するようになっている。
【０００４】
また、ステージ６３の一方の側面には、ガイド部材６２に対して平行に駆動力伝達部材６４が、ステージ６３の他方の側面には、上記駆動力伝達部材６４と平行にリニアスケール６５がそれぞれ設置されており、該リニアスケール６５と対向する位置には測定ヘッド６６を設けて位置検出手段６７を構成するとともに、上記駆動力伝達部材６４と対向する位置には一つの超音波モータ（不図示）を設置し、超音波モータの摩擦部材５６を上記駆動力伝達部材６４の当接面６４ａに対して垂直に当接させてある。
【０００５】
なお、図中、５７は超音波モータ５１を収容するケース、６８は位置検出手段６７より得られた位置情報を基にステージ６３の駆動条件を制御する制御部、６９は制御部６８から出力された信号を基に超音波モータを駆動させるための指令信号を出力するドライバーである。
【０００６】
また、図９に図８の案内装置に用いる超音波モータをケース５７内に収容した状態を示すように、超音波モータ５１は、圧電セラミック板５２の一方の主面に４分割された電極膜５３ａ，５３ｂ，５３ｃ，５３ｄを有し、対角に位置する電極膜５３ａと電極膜５３ｄを結線するとともに、対角に位置する電極膜５３ｂと電極膜５３ｃを結線し、かつ他方の主面には、ほぼ全面に電極膜（不図示）を形成した振動体５５と、上記圧電セラミック板５２の端面に設けたセラミックスやガラスからなる摩擦部材５６とからなり、上記他方の主面に形成された電極膜をアースするとともに、一方の主面に形成された電極膜５３ｂと電極膜５３ｄにそれぞれ位相を異ならせた電圧を印加することにより、圧電セラミック板５２に縦振動と横振動を発生させ、これらの振動の合力によって摩擦部材５６を楕円運動させるようになっていた。
【０００７】
また、超音波モータ５１は、ケース５７内において両側面をスプリング５８を介して保持してあり、スプリング５９の押圧力によって超音波モータ５１をステージ６３の駆動力伝達部材６４に押圧するようになっていた。
【０００８】
その為、この超音波モータ５１を駆動させると、超音波モータ５１の摩擦部材５６との摩擦駆動によってステージ６３をガイド部材６２に沿って移動させることができ、ステージ６３の移動に伴う位置検出手段６７からの位置情報と、予め設定してあるステージ６３の基準位置情報との偏差に応じて変化するパラメータを基に制御部６８にて例えばＰＩＤ演算処理を行ってドライバー６９に超音波モータ５１への指令信号を出力するフィードバック制御を行うことにより、ステージ６３を移動・位置決めするようになっていた。
【０００９】
ところが、超音波モータ５１の摩擦部材５６やステージ６３の駆動力伝達部材６４は互いに摩耗し、その摩耗粉が駆動力伝達部材６４の当接面６４ａに付着するため、この摩耗粉が超音波モータ５１の摩擦部材５６とステージ６３の駆動力伝達部材６４との間に噛み込むと接触状態が変化することから、ステージ６３の駆動特性を不安定にさせるとともに、超音波モータ５１の摩擦部材５６やステージ６３の駆動力伝達部材６４の摩耗が促進され、短期間の使用で超音波モータ５１や駆動力伝達部材６４を交換しなければならないといった課題があった。
【００１０】
その為、これらの課題に対し、特開平１１−１８４４６号公報には、駆動力伝達部材６４に付着した摩耗粉を除去するため、ブラシやローラあるいはフェルトや剥離爪等を駆動力伝達部材６４に当接させて摩耗粉を除去する技術が開示されている。
【００１１】
しかしながら、ブラシ、ローラ、フェルト、剥離爪等を用いて摩耗粉を除去しようとしても、掻き残しが生じたり、掻き取った摩耗粉が駆動力伝達部材６４に再付着するといった課題があり、確実に摩耗粉を除去することができなかった。
【００１２】
また、特開平１１−１８４４６号公報には、摩耗粉の再付着を防止するためにクリーニング溶液を塗布することが開示されているが、このクリーニング溶液が駆動力伝達部材６４に付着すると、超音波モータ５１の摩擦部材５６とステージ６３の駆動力伝達部材６４との間にすべりが発生し、ステージ６３の駆動特性に悪影響を与えるといった課題があった。
【００１３】
【課題を解決するための手段】
そこで、本発明は上記課題に鑑み、楕円運動を発生させる振動体と、該振動体の楕円運動を伝達する摩擦部材とからなる超音波モータと、該超音波モータの摩擦部材と当接し、摩擦駆動により可動する可動体とから成る超音波モータを可動体の駆動源とする案内装置において、上記超音波モータと上記可動体との当接面に付着する摩耗粉を、上記可動体の当接面における上記超音波モータの摩擦部材との接触領域近傍で、上記可動体の当接面と隙間を設けて、絶縁材料からなる基板上に、それぞれ正負に帯電させる一対の櫛歯状の吸着用電極を形成するとともに、該吸着用電極上に絶縁保護膜を被着してなる少なくとも一つの吸着部材と、該吸着部材の吸着用電極に電圧を印加する高圧電源とからなる吸着手段により、静電気力により集塵することを特徴とする。
【００１４】
また、上記絶縁保護膜は、チタン酸バリウム、チタン酸ジルコン酸鉛（ＰＺＴ）、ランタンチタン酸ジルコン酸鉛、マグネシウムニオブ酸鉛あるいはこれらの混合物を主成分とするセラミック膜からなることを特徴とする。
【００１５】
さらには、上記可動体の当接面に上記超音波モータの摩擦部材よりも小さな幅を有する溝を形成し、吸着手段として上記溝底面に設けた吸着用電極と、この吸着用電極に電荷を帯電させるために電圧を印加する高圧電源とからなるものを用いることが好ましい。
【００１６】
【発明の実施の形態】
以下、本発明の実施形態について説明する。
【００１７】
図１は超音波モータを可動体の駆動源とする本発明の案内装置の参考例を示す斜視図である。なお、従来例と同一部分については同一符号で示す。
【００１８】
この案内装置は、ベース盤６１上にクロスローラガイドの如き一対のガイド部材６２を備え、これらガイド部材６２によって可動体としてのステージ６３を直線的に案内するようになっている。
【００１９】
また、ステージ６３の一方の側面には、ガイド部材６２に対して平行に駆動力伝達部材６４を、ステ―ジ６３の他方の側面には、上記駆動力伝達部材６４と平行にリニアスケール６５をそれぞれ設置してあり、このリニアスケール６５と対向する位置には測定ヘッド６６を設けて位置検出手段６７を構成するとともに、上記駆動力伝達部材６４と対向する位置には一つの超音波モータ（不図示）を配置し、超音波モータの摩擦部材５６を上記駆動力伝達部材６４の当接面に対して垂直に当接させてある。
【００２０】
なお、図中、６８は位置検出手段６７より得られた位置情報を基にステージ６３の駆動条件を制御する制御部、６９は上記制御部６８から出力された信号を基に超音波モータを駆動させるための指令信号を出力するドライバーであり、５７は超音波モータを収容するケースである。また、図１に示す超音波モータの構造及び超音波モータの取付構造は、図９に示した超音波モータ５１の構造及び超音波モータ５１の取付構造と同一であるため、ここでは説明を省略する。
【００２１】
また、駆動力伝達部材６４の当接面６４ａには、点線で示す超音波モータの摩擦部材５６との接触領域Ｓの近傍上下に吸着用電極１をそれぞれ設けてあり、各吸着用電極１は高圧電源２と接続することにより、上記超音波モータの摩擦部材５６と上記ステージ６３に備える駆動力伝達部材６４との摩擦駆動によって発生し、駆動力伝達部材６４の当接面６４ａにおける接触領域Ｓに付着する摩耗粉を静電気力により集塵する吸着手段を構成してある。
【００２２】
即ち、本件発明者らは、摩耗粉に着目し研究を行っていたところ、摩擦部材５６と駆動力伝達部材６４との摺動によって発生した摩耗粉は帯電しており、この摩耗粉の帯電状態と異なる極性に帯電させたものを駆動力伝達部材６４の当接面６４ａにおける接触領域Ｓの近傍に配置すれば、摩耗粉を静電気力によって接触領域Ｓ外へ移動させることができるため、駆動力伝達部材６４と摩擦部材５６との間に摩耗粉が噛み込むことを防止できることを見出し、本発明に至った。
【００２３】
具体的には、摩擦部材５６や駆動力伝達部材６４がセラミックスやサファイヤあるいはガラスによって形成されている場合、これらの材料の摩耗粉は正に帯電することから、このような時には吸着用電極１を負に帯電させるようにすれば良く、また、摩擦部材５６や駆動力伝達部材６４が金属や樹脂によって形成されている場合、これらの材料の摩耗粉は負に帯電することから、このような時には吸着用電極１を正に帯電させるようにすれば良い。
【００２４】
その為、ドライバー６９より指令信号を出力して超音波モータの摩擦部材５６を楕円運動させると、駆動力伝達部材６４との摩擦駆動によってステージ６３をガイド部材６２に沿って移動させることができ、ステージ６３の移動に伴う位置検出手段６７からの位置情報と、予め設定してあるステージ６３の基準位置情報との偏差に応じて変化するパラメータを基に制御部６８にて例えばＰＩＤ演算処理を行ってドライバー６９に超音波モータへの指令信号を出力するフィードバック制御を行うことにより、ステージ６３を所定の条件で移動させることができる。
【００２５】
そして、本発明の案内装置によれば、超音波モータの摩擦部材５６とステージ６３に備える駆動力伝達部材６４との摩擦駆動によって発生した摩耗粉を静電気力によって吸着用電極１に吸着させ、駆動力伝達部材６４の当接面６４ａにおける接触領域Ｓに摩耗粉が殆ど残らないようにすることができるため、駆動力伝達部材６４と摩擦部材５６との間に摩耗粉が噛み込むことがなく、常に安定した接触状態を得ることができるため、超音波モータの駆動によってステージ６３を安定して駆動させることができ、１μｍ程度の移動精度や１μｍ以下の位置決め精度が要求されるような場合でも精度良く移動・位置決めすることができる。
【００２６】
なお、吸着用電極１の形態としては特に限定するものではなく、例えば、金属箔、金属薄板、導線、導体膜を用いることができ、駆動力伝達部材６４の当接面６４ａへの取り付けにあたっては、駆動力伝達部材６４の材質との相性を考慮して接着やメタライズ等を用いれば良い。また、図１では接触領域Ｓを挟むように２つの吸着用電極１を設けた例を示したが、少なくとも何れか一方にのみ形成してあれば良い。
【００２７】
ところで、摩耗粉の帯電状態は、j.Henniker:Nature,196(1962)474等によって確認された素材の帯電特性結果を用いたり、実際に摩擦させてその帯電量を測定すれば良い。また、吸着用電極１を帯電させる電荷量は、摩耗粉の大きさや接触領域Ｓとの距離に依存するが、予め摩耗粉の吸着できる電荷量を確認して決定すれば良い。
【００２８】
また、摩耗粉の帯電状態が判断し難い場合、一方の吸着用電極１を正に帯電させ、他方の吸着用電極１を負に帯電させることにより、摩耗粉の帯電状態に関係なく、いずれか一方の吸着用電極１に摩耗粉を吸着させることができる。
【００２９】
次に、本発明の他の様々な実施形態について説明する。
【００３０】
図２に示す実施形態は、吸着手段を、吸着用電極を具備した吸着部材１０と、吸着部材１０の吸着用電極に電荷を帯電させるために電圧を印加する高圧電源２とから構成する以外は図１に示す案内装置と同様の構造をしたもので、上記吸着部材１０は、点線で示す駆動力伝達部材６４の当接面６４ａにおける接触領域Ｓの近傍で、駆動力伝達部材６４の当接面６４ａと約０．５ｍｍ以下の隙間を設け、吸着用電極が当接面６４ａと対向するように設置してあり、上記吸着部材１０は、超音波モータを挟んで両側にそれぞれ一つずつ設けてある。
【００３１】
この実施形態によれば、吸着部材１０の吸着用電極を、駆動力伝達部材６４と摩擦部材５６との摩擦駆動によって発生した摩擦粉の帯電状態と異なる極性に帯電させておくことにより、ステージ６３の移動によって駆動力伝達部材６４の当接面６４ａに付着する摩耗粉が吸着部材１０と対向する位置に来たときに、上記摩耗粉を静電気力によって吸着部材１０に吸着させることができるため、駆動力伝達部材６４の当接面６４ａにおける接触領域Ｓに付着する摩耗粉を除去し、駆動力伝達部材６４と摩擦部材５６との間に摩耗粉が噛み込むことを防止することができるため、常に安定した接触状態を得ることができ、超音波モータの駆動によって１μｍ程度の移動精度や１μｍ以下の位置決め精度が要求されるような場合でもステージ６３を精度良く移動・位置決めすることができる。
【００３２】
ところで、上記吸着部材１０としては、図３（ａ）に示すように、セラミックス等の絶縁材料からなる基板１２上に、金属箔、金属薄板、導体膜等からなる吸着用電極１１を形成し、さらにこの吸着用電極１１上に、絶縁保護膜１３としてポリイミドテープ等の樹脂膜、又はチタン酸バリウム、チタン酸ジルコン酸鉛（ＰＺＴ）、ランタンチタン酸ジルコン酸鉛、マグネシウムニオブ酸鉛あるいはこれらの混合物を主成分とするセラミック膜を被着したものを用いることができる。特に、チタン酸バリウム、チタン酸ジルコン酸鉛（ＰＺＴ）、ランタンチタン酸ジルコン酸鉛、マグネシウムニオブ酸鉛あるいはこれらの混合物を主成分とするセラミック膜は、上記樹脂膜と比較して誘電率が高いため、大きな静電気力を得ることができるため、摩耗粉の吸着力を大幅に向上させることができる。なお、このようなセラミック膜を有する吸着部材１０を製作するには、例えば、チタン酸ジルコン酸鉛（ＰＺＴ）、ランタンチタン酸ジルコン酸鉛、マグネシウムニオブ酸鉛あるいはこれらの混合物に溶媒やバインダーを添加混合してスラリーを形成し、テープ成形にて製作した厚み数百μｍ〜数ｍｍのシートを複数枚用意し、数枚のシートを重ねた後、吸着用電極１１を設け、さらにセラミック膜となる残りのシートを積み重ね、加熱しながら加圧することにより吸着用電極１１が埋設された積層体を形成し、しかる後、焼成することにより得ることができる。
【００３３】
また、摩耗粉の帯電状態が判断し難い場合、図３（ｂ）に示すように、吸着用電極１のパターン形状を一対の櫛歯状とし、一方の櫛歯状をした吸着用電極１１を正に帯電させ、他方の櫛歯状をした吸着用電極１１を負に帯電させることにより、摩耗粉の帯電状態に関係なく、摩耗粉を吸着部材１０に吸着させることができる。
【００３４】
図４に示す実施形態は、吸着手段を、シート状の吸着用電極２１を２つのローラ２２で張架したコンベア機構によって駆動させることができる吸着部材２０と、吸着部材２０の吸着用電極２１に電荷を帯電させるために電圧を印加する高圧電源２とから構成する以外は図１に示す案内装置と同様の構造をしたもので、上記吸着部材２０は、点線で示す駆動力伝達部材６４の当接面６４ａにおける接触領域Ｓの近傍で、駆動力伝達部材６４の当接面６４ａと約０．５ｍｍ以下の隙間を設け、吸着用電極２１が当接面６４ａと対向するように設置してあり、上記吸着部材２０は、超音波モータを挟んで両側にそれぞれ一つずつ設けてある。
【００３５】
この実施形態によれば、吸着部材２０の吸着用電極２１を、駆動力伝達部材６４と摩擦部材５６との摩擦駆動によって発生した摩擦粉の帯電状態と異なる極性に帯電させておくことにより、ステージ６３の移動によって駆動力伝達部材６４の当接面６４ａに付着する摩耗粉が吸着部材２０と対向する位置に来たときに、上記摩耗粉を静電気力によって吸着部材２０に吸着させることができるため、駆動力伝達部材６４の当接面６４ａにおける接触領域Ｓに付着する摩耗粉を除去し、駆動力伝達部材６４と摩擦部材５６との間に摩耗粉が噛み込むことを防止することができるため、常に安定した接触状態を得ることができ、超音波モータの駆動によって１μｍ程度の移動精度や１μｍ以下の位置決め精度が要求されるような場合でもステージ６３を精度良く移動・位置決めすることができる。
【００３６】
また、この吸着部材２０は、シート状の吸着用電極２１を２つのローラ２２で張架したコンベア機構によって回転させることができるため、シート状をした吸着用電極２１の駆動力伝達部材６４の当接面６４ａと対向する領域に摩耗粉が付着し、摩耗粉の吸着能力が低下した場合、コンベア機構によってシート状をした吸着用電極２１を移動させ、摩耗粉が吸着されていない新しい面を駆動力伝達部材６４の当接面６４ａと順次対向させることができるため、図１や図２に示す実施形態と比較して長期間にわたって案内装置を駆動させることができる。
【００３７】
ところで、上記吸着部材２０を形成する吸着用電極２１としては、例えば、金属箔をポリイミドシートで挟み込んだものを用いれば良い。なお、吸着用電極２１への通電は、入電端子からスリップリングを用いて行えば良い。また、駆動力伝達部材６４と反対側の吸着用電極２１には分離つめを当接させておくことにより、吸着用電極２１に吸着させた摩耗粉を分離つめで掻き落とし、吸着用電極２１の再生を行うようにしても構わない。ただし、分離つめで摩耗粉を掻き落とす場合、その近傍に摩耗粉の回収機構を設けることが好ましく、このような回収機構を設けることで摩耗粉を周囲にまき散らすことがなく、半永久的に使用することができる。
【００３８】
図５に示す実施形態は、ステージ６３に備える駆動力伝達部材６４の当接面６４ａに超音波モータの摩擦部材５６よりも小さな幅を有する溝３２を複数個刻設するとともに、吸着手段として図６（ａ）に示すように各溝底部３２ａに設けた吸着用電極３１と、これらの吸着用電極３１に電荷を帯電させるために電圧を印加する高圧電源２とから構成する以外は図１に示す案内装置と同様の構造をしたものである。
【００３９】
ここで、駆動力伝達部材６４の当接面６４ａに形成する溝３２のパターン形状としては特に限定するものではなく、例えば、図７（ａ）に示すように、ステージ６３の移動方向に沿って延びる溝３２をステージ６３の移動方向に対して垂直な方向に複数個平行に並設したものや、図７（ｂ）に示すように、ステージ６３の移動方向に対して斜め方向に延びる溝３２をステージ６３の移動方向に複数個平行に並設したもの、あるいは図７（ｃ）に示すように、ステージ６３の移動方向に対して斜めに延びる溝３２をクロス状に配置したものなど、様々なパターン形状を採用することができる。
【００４０】
この実施例によれば、駆動力伝達部材６４の当接面６４ａに溝３２を形成したことから、駆動力伝達部材６４と摩擦部材５６との摩擦駆動によって発生し、駆動力伝達部材６４の当接面６４ａや摩擦部材５６に付着する摩擦粉を溝３２内に欠き落とすことができるため、駆動力伝達部材６４と摩擦部材５６との間に摩耗粉が噛み込むことを効果的に防止することができる。
【００４１】
また、溝底面３２ａには吸着用電極３１を設けてあり、この吸着用電極３１を摩耗粉の帯電状態と異なる極性に帯電させておくことにより、溝３２内に欠き落とされた摩耗粉を静電気力によって吸着用電極３１に吸着させて集塵することができるため、溝３２内に付着した摩耗粉が再度摩擦部材５６や駆動力伝達部材６４の当接面６４ａに付着することを防止することができる。
【００４２】
その為、駆動力伝達部材６４の当接面６４ａにおける接触領域Ｓに付着する摩耗粉を効率良く除去し、駆動力伝達部材６４と摩擦部材５６との間に摩耗粉が噛み込むことを効果的に防止することができるため、常に安定した接触状態を得ることができ、超音波モータの駆動によって１μｍ程度の移動精度や１μｍ以下の位置決め精度が要求されるような場合でもステージ６３を精度良く移動・位置決めすることができる。
【００４３】
ところで、このような効果を得るには、溝３２の幅を超音波モータの摩擦部材５６よりも小さくする必要であり、好ましくは０．０３ｍｍ〜１ｍｍの幅とすることが好ましい。即ち、溝３２の幅Ｗが超音波モータの摩擦部材５６と同等又は大きくなると、摩擦部材５６と駆動力伝達部材６４との接触状態が変化し、ステージ６３の駆動特性に悪影響を及ぼしたり、摩擦部材５６の摩耗を促進させ、さらには摩擦部材５６によって溝３２のエッジ部を破損させるといった不都合があり、特に溝３２の幅Ｗが１ｍｍを超えると、上述した問題が顕著に現れ始めるからであり、逆に、溝３２の幅Ｗが０．０３ｍｍ未満となると、溝底面３２ａに吸着用電極３１を設けることが難しいからである。
【００４４】
また、溝３２の深さＬが１ｍｍを超えると、溝３２の開口部付近に付着する摩耗粉と溝底面３２ａの吸着用電極３１との距離は離れすぎ、摩耗粉に作用する静電吸着力が小さくなりすぎるため、摩耗粉を溝３２内に保持することが難しくなる。一方、溝３２の深さＬが、０．０５ｍｍ未満となると、溝３２内に欠き落とされた摩耗粉の集塵量が著しく低下する。その為、溝３２の深さＬは０．０５〜１ｍｍとすることが好ましい。
【００４５】
なお、溝３２は駆動力伝達部材６４の当接面６４ａのうち、少なくとも超音波モータの摩擦部材５６との接触領域Ｓに形成してあれば良い。
【００４６】
以上、本実施形態では、可動体が直線運動する案内装置を例にとって説明したが、可動体が回転運動する案内装置にも適用できることは言う迄もなく、さらに、可動体を駆動させる超音波モータについても、多重モード型のものに限らず、単一振動モードの定在波型や進行波、複数振動モードのモード変換型、複合振動型の超音波モータであっても構わない。
【００４７】
このように、本発明の要旨を逸脱しない範囲であれば、種々改良や変更したものでも構わない。
【００４８】
【実施例】
（実施例１）ここで、図１に示す案内装置（参考例）と、図８に示す従来の案内装置（従来例１）、及び図８に示す従来の案内装置に、摩耗粉を掻き取るためのブラシを備えたもの（従来例２）をそれぞれ用意し、各案内装置を駆動させ、超音波モータ５１の摩擦部材５６の摩耗量と、案内装置の寿命について調べる実験を行った。
【００４９】
本実験にあたっては、超音波モータ５１の振動体５５の寸法を長さ３０ｍｍ、幅７．５ｍｍ、厚み３ｍｍとし、チタン酸ジルコン酸鉛系の圧電セラミックスにより形成したものを用いるとともに、振動体５５に接合する摩擦部材５６にアルミナセラミックスを用い、その寸法を長さ４．２ｍｍ、直径３ｍｍの円柱とし、かつ当接面を曲率半径が７ｍｍの球面とした。
【００５０】
また、案内装置を構成するガイド部材６２には、ストロークが１００ｍｍのクロスローラーガイドを用い、上記ガイド部材６２を介して５ｋｇの重さを有するステージ６３を移動させるようにした。また、超音波モータの摩擦部材５６と当接する駆動力伝達部材６４にはアルミナセラミックスを用い、かつ摩擦部材５６との当接面６４ａを算術平均粗さ（Ｒａ）で０．０５μｍとした。
【００５１】
そして、本発明の案内装置においては、駆動力伝達部材６４の当接面６４ａにおける摩擦部材５６との接触領域Ｓの軸線より１ｍｍ離れた位置に、吸着用電極１として、直径が１ｍｍの銅線を２本接着剤にて当接面６４ａに固定した。
また、高圧電源２により吸着用電極１に通電することにより、吸着用電極１に１ｋＶの負の電荷が帯電するようにした。
【００５２】
また、摩耗粉を掻き取るためのブラシを備えた従来の案内装置は、超音波モータを挟んで両側に、駆動力伝達部材６４の当接面６４ａと当接するようブラシを配置した。
【００５３】
そして、制御部６８に予め設定しておくステージ１３のプロファイルとして移動距離１００ｍｍ、加減速度０．０３Ｇ、最高速度１００ｍｍ／ｓに設定した台形制御とし、超音波モータ５１は４０ｋＨｚの駆動周波数で駆動させるようにした。そして、この条件でステージ６３を５００ｋｍ駆動させた後の摩耗粉の除去状態と、摩擦部材５６の摩耗量をそれぞれ測定するとともに、案内装置の寿命を測定した。なお、案内装置の寿命については、位置検出手段６７から得られる実際の位置信号と基準位置信号との偏差が１μｍを超えると、ステージ６３を安定して駆動させることができなくなるため、偏差が１μｍを超えたステージ６３の移動距離を寿命とした。
【００５４】
それぞれの結果は表１に示す通りである。
【００５５】
【表１】

【００５６】
この結果、摩耗粉の除去手段を備えていない従来例１の案内装置は、摩耗粉の噛み込みにより、摩擦部材５６の摩耗量が多く、また、ステージ６３の移動距離が２００ｋｍで偏差が１μｍを超え、寿命が短かった。
【００５７】
また、摩耗粉の除去手段としてブラシを備えた従来例２の案内装置は、摩擦部材５６の摩耗量は少なかったものの、ステージ６３の移動距離が３００ｋｍをすぎたところから、ところどころで偏差が１μｍを超えた。この理由について調べて見ると、ブラシにより取り除いた摩耗粉が駆動力伝達部材６４の当接面６４ａに再付着し、再付着した摩耗粉の噛み込みによるものであった。
【００５８】
これに対し、本発明の案内装置は、摩耗粉を吸着用電極１に付着させることができ、駆動力伝達部材６４の当接面６４における摩擦部材５６との接触領域Ｓには殆ど摩耗粉が残っていないため、摩擦部材５６の摩耗量が極めて少なく、また、ステージ６３を５００ｋｍ駆動させても偏差が１μｍを超えることがないため、長時間安定して駆動させることができ、優れていた。
（実施例２）
次に、図２に示す本発明の案内装置を用い、実施例１と同様の実験を行った。
【００５９】
なお、吸着手段を構成する吸着部材１０には、吸着用電極１１として縦２３ｍｍ、横２８ｍｍの銅箔を、縦２５ｍｍ、横３０ｍｍのセラミック板１２に張り付け、その上に絶縁保護膜１３としてポリイミドテープを張り付けたものを用い、超音波モータ５１の両端に２箇所配置した。ただし、吸着部材１０と駆動力伝達部材６４との隙間は０．５ｍｍに設定した。そして、高圧電源２により吸着用電極１１に通電し、吸着用電極１１に１ｋＶの負の電荷が帯電するようにした。
【００６０】
結果は表２に示す通りである。
【００６１】
【表２】

【００６２】
この結果、図２に示す本発明の案内装置は、駆動力伝達部材６４に付着する摩耗粉を吸着部材１０に付着させることができるため、駆動力伝達部材６４の当接面６４における摩擦部材５６との接触領域Ｓには殆ど摩耗粉が残っておらず、摩擦部材５６の摩耗量が極めて少なく、また、ステージ６３を５００ｋｍ駆動させても偏差が１μｍを超えることがないため、長時間安定して駆動させることができた。
（実施例３）
次に、図４に示す本発明の案内装置を用い、実施例１と同様の実験を５０００ｋｍにわたって行った。
【００６３】
なお、吸着手段を構成する吸着部材２０は、銅箔をポリイミドシートで挟み込んだ、幅３０ｍｍのシート状の吸着用電極２１を、一対のローラ２２によって張架したコンベア構造とし、この吸着部材２０を超音波モータ５１の両端に２箇所配置した。ただし、吸着部材２０と駆動力伝達部材６４との隙間は０．５ｍｍに設定した。そして、高圧電源２により吸着用電極２１に通電し、吸着用電極２１に１ｋＶの負の電荷が帯電するようにした。
【００６４】
また、吸着用電極２１を挟んで駆動力伝達部材６４と反対側には、樹脂製の分離つめを５０ｇの力で押しつけ、分離つめで掻き落とした摩耗粉を回収トレーにて集塵するようにした。
【００６５】
ただし、吸着部材２０の吸着用電極２１は、ステージ６３が５００ｋｍ移動する毎に一回転するようにし、１０段階にわけてステップ送りさせた。
【００６６】
この結果、超音波モータ５１の摩擦部材５６の摩耗量は、ステージ６３の移動距離に比例した定常的な摩耗であり、偏摩耗はみられず、駆動中ステージ６３を安定して駆動させることができ、また、摩耗粉の回収機能を有することから、クリーンな環境を要求される半導体製造装置にも適用可能であった。
（実施例４）
次に、図５に示す本発明の案内装置を用い、実施例１と同様の実験を５０００ｋｍにわたって行った。
【００６７】
なお、駆動力伝達部材６４の摩擦部材５６との当接面６４ａに形成する溝３２は、ステージ６３の移動方向に対して４５度の角度をもつ斜めの溝３２とし、１ｍｍピッチで形成するとともに、溝３２の幅Ｗを５０μｍ、溝３２の深さＬを１００μｍとした。また、各溝底面３２ａには厚さ３μｍの銀膜を被着して吸着用電極２１を形成した。
【００６８】
そして、高圧電源２により吸着用電極２１に通電し、吸着用電極２１に１ｋＶの負の電荷が帯電するようにした。
【００６９】
この結果、駆動力伝達部材６４の当接面６４における摩擦部材５６との接触領域Ｓには殆ど摩耗粉が残っておらず、溝３２内に保持されていた。その為、摩擦部材５６の摩耗量が極めて少なく、ステージ６３を５０００ｋｍ駆動させても偏差が１μｍを超えることなく、長時間安定して駆動させることができた。しかも、この実施形態においては、駆動力伝達部材６４の当接面６４に付着する摩耗粉だけでなく、超音波モータ５１の摩擦部材５６に付着する摩耗粉も溝３２内に欠き落とすことができるため、図１乃至図４に示す本発明の他の実施形態と比較して摩擦部材５６に付着する摩耗量を極めて少なくすることができ、駆動力伝達部材６４と摩擦部材５６との接触状態の変化を小さくできるため、ステージ６３の移動中における挙動も安定させることができる。
【００７０】
【発明の効果】
以上のように、本発明によれば、楕円運動を発生させる振動体と、該振動体の楕円運動を伝達する摩擦部材とからなる超音波モータと、該超音波モータの摩擦部材と当接し、摩擦駆動により可動する可動体とから成る超音波モータを可動体の駆動源とする案内装置において、上記超音波モータと上記可動体との摩擦駆動により上記可動体の当接面に付着する摩耗粉を静電気力により集塵する吸着手段を設け、この吸着手段として、可動体の当接面における超音波モータの摩擦部材との接触領域近傍に備える少なくとも一つの吸着用電極と、この吸着用電極に電荷を帯電させるために電圧を印加する高圧電源とからなるものを用いるか、あるいは可動体の当接面における超音波モータの摩擦部材との接触領域近傍で、且つ可動体の当接面と隙間を設けて設置した吸着用電極を備える少なくとも一つの吸着部材と、この吸着部材の吸着用電極に電荷を帯電させるために電圧を印加する高圧電源とからなるものか、さらには可動体の当接面における超音波モータの摩擦部材との接触領域に、摩擦部材よりも小さな幅を有する複数個の溝を形成するとともに、この溝底面に配置した吸着電極と、この吸着用電極に電荷を帯電させるために電圧を印加する高圧電源とからなるものを用いることによって、摩擦駆動によって発生した摩耗粉を、可動体の当接面における摩擦部材との接触領域より除去することができるため、超音波モータと可動体との接触面間に摩耗粉が噛み込むことを防止することができ、可動体を安定して駆動させることができ、可動中における精度が１μｍ、位置決め精度が０．１μｍといった高精度が要求される場合でも精度良く可動体を可動、位置決めすることができるとともに、さらには周囲の雰囲気を汚染することがないため、真空雰囲気等で使用する場合でも好適に使用することができる。
【図面の簡単な説明】
【図１】超音波モータを可動体の駆動源とする本発明の案内装置の一例を示す斜視図である。
【図２】超音波モータを可動体の駆動源とする本発明の案内装置の他の例を示す斜視図である。
【図３】（ａ）（ｂ）はそれぞれ図３の案内装置に備える吸着部材の構造を示す一部を破断した斜視図である。
【図４】超音波モータを可動体の駆動源とする本発明の案内装置のさらに他の例を示す斜視図である。
【図５】超音波モータを可動体の駆動源とする本発明の案内装置のさらに他の例を示す斜視図である。
【図６】図５の案内装置に備える要部の一部を拡大した断面図である。
【図７】（ａ）（ｂ）（ｃ）はそれぞれ図５の案内装置に備える溝のパターン形状を示す平面図である。
【図８】超音波モータを可動体の駆動源とする従来の案内装置の一例を示す斜視図である。
【図９】ケース内における超音波モータの取付構造を示す一部を破断した断面図である。
【符号の説明】
１，１１，２１，３１：吸着用電極２：高圧電源１０，２０：吸着部材
１２：基板１３：絶縁保護膜２２：ローラ３２：溝３２ａ：溝底面
５１：超音波モータ５２：圧電セラミック体
５３ａ，５３ｂ，５３ｃ，５３ｄ：電極膜
５５：振動体５６：摩擦部材５７：ケース５８：スプリング
５９：スプリング６１：ベース盤６２：ガイド部材６３：ステージ
６４：駆動力伝達部材６５：リニアスケール６６：測定ヘッド
６７：位置検出手段６８：制御部６９：ドライバー[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a guide device that drives a movable body that moves linearly or rotationally with an ultrasonic motor, and is particularly suitable as a guide device used in precision processing machines, precision measurement devices, and semiconductor manufacturing devices. .
[0002]
[Prior art and problems to be solved by the invention]
Ultrasonic motors have the characteristics that the minimum amplitude is as small as nano-order, high-resolution positioning is possible, and the driving force is large due to frictional drive. It has been put to practical use in rotary motion systems such as alarms, and recently it has been tried to apply to linear motion systems.
[0003]
As shown in FIG. 8 as an example of a conventional guide device using an ultrasonic motor as a driving source for a movable body, this guide device includes a pair of guide members 62 such as a cross roller guide on a base board 61. A stage 63 as a movable body is linearly guided by the guide member 62.
[0004]
A driving force transmission member 64 is installed on one side surface of the stage 63 in parallel with the guide member 62, and a linear scale 65 is installed on the other side surface of the stage 63 in parallel with the driving force transmission member 64. A measuring head 66 is provided at a position facing the linear scale 65 to constitute a position detecting means 67, and a single ultrasonic motor (not shown) is disposed at a position facing the driving force transmitting member 64. The friction member 56 of the ultrasonic motor is brought into contact with the contact surface 64a of the driving force transmission member 64 perpendicularly.
[0005]
In the figure, 57 is a case for accommodating the

ultrasonic motor

51, 68 is a control unit for controlling the driving conditions of the stage 63 based on the position information obtained from the

position detecting means

67, and 69 is output from the control unit 68. The driver outputs a command signal for driving the ultrasonic motor based on the received signal.
[0006]
Further, as shown in FIG. 9, the ultrasonic motor 51 used in the guide device of FIG. 8 is housed in the case 57, the ultrasonic motor 51 is divided into four electrode films on one main surface of the piezoelectric ceramic plate 52. 53a, 53b, 53c, 53d, which connects the electrode film 53a and the electrode film 53d located diagonally, and connects the electrode film 53b and the electrode film 53c located diagonally, and on the other main surface Is formed of a vibrating body 55 having an electrode film (not shown) formed on almost the entire surface, and a friction member 56 made of ceramic or glass provided on the end face of the piezoelectric ceramic plate 52, and formed on the other main surface. By grounding the electrode film and applying voltages having different phases to the electrode film 53b and the electrode film 53d formed on one main surface, longitudinal vibration and lateral vibration are generated in the piezoelectric ceramic plate 52. The friction member 56 has been adapted to elliptical motion by the resultant force of these vibrations.
[0007]
In addition, the ultrasonic motor 51 is held on both sides in the case 57 via springs 58, and the ultrasonic motor 51 is pressed against the driving force transmission member 64 of the stage 63 by the pressing force of the spring 59. It was.
[0008]
Therefore, when the ultrasonic motor 51 is driven, the stage 63 can be moved along the guide member 62 by friction drive with the friction member 56 of the ultrasonic motor 51, and position detecting means accompanying the movement of the stage 63. The controller 68 performs, for example, PID calculation processing on the basis of the parameter that changes in accordance with the deviation between the position information from 67 and the preset reference position information of the stage 63, and sends the driver 69 to the ultrasonic motor 51. The stage 63 is moved and positioned by performing feedback control that outputs the command signal.
[0009]
However, the friction member 56 of the ultrasonic motor 51 and the driving force transmission member 64 of the stage 63 are worn away, and the abrasion powder adheres to the contact surface 64a of the driving force transmission member 64. Since the contact state changes when it is engaged between the friction member 56 of 51 and the driving force transmission member 64 of the stage 63, the driving characteristics of the stage 63 are made unstable, and the friction member 56 of the ultrasonic motor 51 and Wear of the driving force transmission member 64 of the stage 63 is promoted, and there is a problem that the ultrasonic motor 51 and the driving force transmission member 64 must be replaced for a short period of use.
[0010]
Therefore, in response to these problems, Japanese Patent Application Laid-Open No. 11-18446 discloses that a brush, a roller, a felt, a peeling claw, or the like is attached to the driving force transmission member 64 in order to remove the abrasion powder adhering to the driving force transmission member 64. A technique for removing abrasion powder by abutting is disclosed.
[0011]
However, even if it is attempted to remove the wear powder using a brush, roller, felt, peeling claw, etc., there is a problem that scraping remains or the scraped wear powder is reattached to the driving force transmission member 64. The abrasion powder could not be removed.
[0012]
Japanese Patent Laid-Open No. 11-18446 discloses that a cleaning solution is applied in order to prevent the reattachment of wear powder. When this cleaning solution adheres to the driving force transmission member 64, ultrasonic waves are applied. There has been a problem that slip occurs between the friction member 56 of the motor 51 and the driving force transmission member 64 of the stage 63, which adversely affects the driving characteristics of the stage 63.
[0013]
[Means for Solving the Problems]
In view of the above problems, the present invention is in contact with an ultrasonic motor including a vibrating body that generates an elliptical motion and a friction member that transmits the elliptical motion of the vibrating body, and a friction member of the ultrasonic motor. In a guide device using an ultrasonic motor composed of a movable body movable by driving as a drive source of the movable body, wear powder adhering to the contact surface between the ultrasonic motor and the movable body is removed. A pair of gaps between the contact surface of the movable body and the friction member of the ultrasonic motor on the contact surface of the movable body so as to be positively and negatively charged on the substrate made of an insulating material. And at least one adsorbing member formed by depositing an insulating protective film on the adsorbing electrode, and a high-voltage power source for applying a voltage to the adsorbing electrode of the adsorbing member; Dust is collected by electrostatic force by adsorption means consisting of It is characterized by that.
[0014]
The insulating protective film is made of a ceramic film mainly composed of barium titanate, lead zirconate titanate (PZT), lead lanthanum zirconate titanate, lead magnesium niobate, or a mixture thereof. .
[0015]
Further, a groove having a width smaller than that of the friction member of the ultrasonic motor is formed on the contact surface of the movable body, and an adsorption electrode provided on the bottom surface of the groove as adsorption means, and an electric charge is applied to the adsorption electrode. It is preferable to use what consists of a high voltage power supply which applies a voltage in order to charge.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described.
[0017]
FIG. 1 is a perspective view showing a reference example of a guide device according to the present invention using an ultrasonic motor as a drive source for a movable body. In addition, about the same part as a prior art example, it shows with the same code | symbol.
[0018]
This guide device is provided with a pair of guide members 62 such as cross roller guides on a base board 61 and linearly guides a stage 63 as a movable body by these guide members 62.
[0019]
A driving force transmission member 64 is provided on one side surface of the stage 63 in parallel with the guide member 62, and a linear scale 65 is provided on the other side surface of the stage 63 in parallel with the driving force transmission member 64. A measuring head 66 is provided at a position facing the linear scale 65 to constitute a position detecting means 67, and a single ultrasonic motor (not suitable) is disposed at a position facing the driving force transmitting member 64. The friction member 56 of the ultrasonic motor is in contact with the contact surface of the driving force transmission member 64 perpendicularly.
[0020]
In the figure, 68 is a control unit for controlling the driving conditions of the stage 63 based on the position information obtained from the position detecting means 67, and 69 is for driving the ultrasonic motor based on the signal output from the control unit 68. A driver for outputting a command signal for causing the motor to be operated, and 57 is a case for accommodating the ultrasonic motor. The structure of the ultrasonic motor and the attachment structure of the ultrasonic motor shown in FIG. 1 are the same as the structure of the ultrasonic motor 51 and the attachment structure of the ultrasonic motor 51 shown in FIG. To do.
[0021]
Further, the suction electrodes 1 are provided on the contact surface 64a of the driving force transmission member 64 in the vicinity of the contact area S with the friction member 56 of the ultrasonic motor indicated by the dotted line. By connecting to the high-voltage power supply 2, the friction region 56 of the ultrasonic motor and the driving force transmission member 64 provided on the stage 63 generate frictional driving, and the contact region S on the contact surface 64 a of the driving force transmission member 64 is generated. An adsorbing means for collecting the wear powder adhering to the surface by electrostatic force is configured.
[0022]
That is, the inventors of the present invention have been conducting research while paying attention to the wear powder, and the wear powder generated by sliding between the friction member 56 and the driving force transmission member 64 is charged, and the charged state of the wear powder. If the one charged to a polarity different from that of the contact area S on the contact surface 64a of the driving force transmission member 64 is disposed near the contact area S, the wear powder can be moved out of the contact area S by electrostatic force. The present inventors have found that wear powder can be prevented from biting between the transmission member 64 and the friction member 56 and have reached the present invention.
[0023]
Specifically, when the friction member 56 and the driving force transmission member 64 are formed of ceramics, sapphire, or glass, the wear powder of these materials is positively charged. If the friction member 56 and the driving force transmission member 64 are made of metal or resin, the wear powder of these materials is negatively charged. The adsorption electrode 1 may be positively charged.
[0024]
Therefore, when a command signal is output from the driver 69 and the friction member 56 of the ultrasonic motor is moved elliptically, the stage 63 can be moved along the guide member 62 by friction drive with the driving force transmission member 64. The control unit 68 performs, for example, PID calculation processing based on a parameter that changes in accordance with the deviation between the position information from the position detection unit 67 accompanying the movement of the stage 63 and the preset reference position information of the stage 63. By performing feedback control that outputs a command signal to the ultrasonic motor to the driver 69, the stage 63 can be moved under a predetermined condition.
[0025]
According to the guide device of the present invention, the abrasion powder generated by the friction drive between the friction member 56 of the ultrasonic motor and the driving force transmission member 64 provided in the stage 63 is adsorbed to the adsorption electrode 1 by electrostatic force and driven. Since it is possible to keep almost no abrasion powder in the contact region S on the contact surface 64a of the force transmission member 64, the abrasion powder does not bite between the driving force transmission member 64 and the friction member 56. Since a stable contact state can be obtained at all times, the stage 63 can be driven stably by driving the ultrasonic motor, and accuracy is required even when movement accuracy of about 1 μm or positioning accuracy of 1 μm or less is required. Can move and position well.
[0026]
The form of the attracting electrode 1 is not particularly limited. For example, a metal foil, a thin metal plate, a conducting wire, or a conductor film can be used. In attaching the driving force transmitting member 64 to the contact surface 64a, In consideration of compatibility with the material of the driving force transmission member 64, adhesion, metallization, or the like may be used. Moreover, although the example which provided the two electrodes 1 for adsorption | suction so that the contact area S was pinched | interposed was shown in FIG. 1, it should just be formed only in at least any one.
[0027]
By the way, the charged state of the wear powder may be measured by using the charging characteristic result of the material confirmed by j. Henniker: Nature, 196 (1962) 474 or by actually rubbing it. The amount of charge for charging the adsorption electrode 1 depends on the size of the wear powder and the distance from the contact area S, but may be determined in advance by confirming the amount of charge that can be absorbed by the wear powder.
[0028]
In addition, when it is difficult to determine the charged state of the wear powder, one of the adsorption electrodes 1 is positively charged and the other of the adsorption electrodes 1 is negatively charged, regardless of the charged state of the wear powder. Wear powder can be adsorbed to one of the adsorption electrodes 1.
[0029]
Next, various other embodiments of the present invention will be described.
[0030]
In the embodiment shown in FIG. 2, the adsorbing means is composed of an adsorbing member 10 having an adsorbing electrode and a high-voltage power supply 2 that applies a voltage to charge the adsorbing electrode of the adsorbing member 10. The suction member 10 has a structure similar to that of the guide device shown in FIG. A gap of about 0.5 mm or less is provided with the surface 64a, and the adsorption electrode is installed so as to face the contact surface 64a. The adsorption members 10 are provided on both sides of the ultrasonic motor. It is.
[0031]
According to this embodiment, the stage 63 is obtained by charging the suction electrode of the suction member 10 to a polarity different from the charged state of the friction powder generated by the frictional drive of the driving force transmission member 64 and the friction member 56. When the wear powder adhering to the contact surface 64a of the driving force transmission member 64 comes to a position facing the adsorption member 10 by the movement of the wear force, the wear powder can be adsorbed to the adsorption member 10 by electrostatic force. Since the wear powder adhering to the contact region S on the contact surface 64a of the driving force transmission member 64 can be removed and the wear powder can be prevented from being caught between the driving force transmission member 64 and the friction member 56. A stable contact state can be obtained at all times, and the stage 63 can be precisely adjusted even when a moving accuracy of about 1 μm or a positioning accuracy of 1 μm or less is required by driving the ultrasonic motor. It can be moved and positioned well.
[0032]
By the way, as the adsorption member 10, as shown in FIG. 3A, an adsorption electrode 11 made of a metal foil, a metal thin plate, a conductor film, or the like is formed on a substrate 12 made of an insulating material such as ceramics. Further, on the electrode 11 for adsorption, a resin film such as polyimide tape as the insulating protective film 13, or barium titanate, lead zirconate titanate (PZT), lead lanthanum zirconate titanate, lead magnesium niobate or a mixture thereof It is possible to use a ceramic film mainly composed of In particular, a ceramic film mainly composed of barium titanate, lead zirconate titanate (PZT), lead lanthanum zirconate titanate, lead magnesium niobate or a mixture thereof has a higher dielectric constant than the resin film. Therefore, since a large electrostatic force can be obtained, the adsorption power of the wear powder can be greatly improved. In order to manufacture the adsorption member 10 having such a ceramic film, for example, a solvent or binder is added to lead zirconate titanate (PZT), lead lanthanum zirconate titanate, lead magnesium niobate, or a mixture thereof. A slurry is formed by mixing, a plurality of sheets having a thickness of several hundred μm to several mm prepared by tape molding are prepared, and after several sheets are stacked, an adsorption electrode 11 is provided, and further a ceramic film is formed. It can be obtained by stacking the remaining sheets and pressurizing them while heating to form a laminate in which the adsorption electrode 11 is embedded, and then firing.
[0033]
Further, when it is difficult to determine the charged state of the wear powder, as shown in FIG. 3 (b), the pattern shape of the adsorption electrode 1 is a pair of comb teeth, and the adsorption electrode 11 having one comb teeth is formed. By positively charging and negatively charging the other comb-like adsorption electrode 11, the abrasion powder can be adsorbed to the adsorption member 10 regardless of the charged state of the abrasion powder.
[0034]
In the embodiment shown in FIG. 4, the adsorbing means can be driven by an adsorbing member 20 that can be driven by a conveyor mechanism in which a sheet-like adsorbing electrode 21 is stretched by two rollers 22, and the adsorbing electrode 21 of the adsorbing member 20. The suction member 20 has a structure similar to that of the guide device shown in FIG. 1 except that it includes a high-voltage power supply 2 that applies a voltage to charge the charge. In the vicinity of the contact area S on the contact surface 64a, a clearance of about 0.5 mm or less is provided with the contact surface 64a of the driving force transmission member 64, and the suction electrode 21 is disposed so as to face the contact surface 64a. The adsorption member 20 is provided on each side of the ultrasonic motor.
[0035]
According to this embodiment, the stage is provided by charging the suction electrode 21 of the suction member 20 to a polarity different from the charged state of the friction powder generated by the frictional drive of the driving force transmission member 64 and the friction member 56. Since the wear powder adhering to the contact surface 64a of the driving force transmission member 64 due to the movement of 63 comes to a position facing the adsorption member 20, the wear powder can be adsorbed to the adsorption member 20 by electrostatic force. Since the wear powder adhering to the contact area S on the contact surface 64a of the driving force transmission member 64 can be removed, it is possible to prevent the wear powder from being caught between the driving force transmission member 64 and the friction member 56. The stage 63 can always obtain a stable contact state, and even when a moving accuracy of about 1 μm or a positioning accuracy of 1 μm or less is required by driving the ultrasonic motor. Can be moved and positioned with high accuracy.
[0036]
Further, since the suction member 20 can be rotated by a conveyor mechanism in which the sheet-like suction electrode 21 is stretched by two rollers 22, the contact of the driving force transmission member 64 of the sheet-like suction electrode 21 is prevented. When wear powder adheres to the area facing the contact surface 64a and the adsorption capacity of the wear powder decreases, the sheet-like adsorption electrode 21 is moved by the conveyor mechanism to drive a new surface on which the wear powder is not adsorbed. Since it can be made to oppose sequentially with the contact surface 64a of the force transmission member 64, a guide apparatus can be driven over a long period of time compared with embodiment shown in FIG.1 and FIG.2.
[0037]
By the way, as the adsorption electrode 21 forming the adsorption member 20, for example, a metal foil sandwiched between polyimide sheets may be used. The energization of the adsorption electrode 21 may be performed using a slip ring from the incoming terminal. Further, by holding a separation pawl against the suction electrode 21 on the side opposite to the driving force transmitting member 64, the abrasion powder adsorbed on the suction electrode 21 is scraped off by the separation pawl, and the suction electrode 21 Playback may be performed. However, when abrasion powder is scraped off by a separation nail, it is preferable to provide a wear powder recovery mechanism in the vicinity thereof. By providing such a recovery mechanism, wear powder is not scattered around and used semipermanently. be able to.
[0038]
In the embodiment shown in FIG. 5, a plurality of grooves 32 having a smaller width than the friction member 56 of the ultrasonic motor are formed on the contact surface 64 a of the driving force transmission member 64 provided in the stage 63, and the suction means is illustrated. As shown in FIG. 6 (a), FIG. 1 shows a configuration except that the suction electrodes 31 are provided at the groove bottom portions 32a and the high voltage power source 2 applies a voltage to charge the suction electrodes 31 with electric charges. It has the same structure as the guide device shown.
[0039]
Here, the pattern shape of the groove 32 formed on the contact surface 64a of the driving force transmission member 64 is not particularly limited. For example, as shown in FIG. A plurality of extending grooves 32 arranged in parallel in a direction perpendicular to the moving direction of the stage 63, or a groove 32 extending obliquely with respect to the moving direction of the stage 63, as shown in FIG. Are arranged in parallel in the moving direction of the stage 63, or as shown in FIG. 7C, the grooves 32 extending obliquely with respect to the moving direction of the stage 63 are arranged in a cross shape. Various pattern shapes can be employed.
[0040]
According to this embodiment, since the groove 32 is formed in the contact surface 64 a of the driving force transmission member 64, the groove 32 is generated by friction drive between the driving force transmission member 64 and the friction member 56, and the contact of the driving force transmission member 64 is reduced. Since the friction powder adhering to the contact surface 64a and the friction member 56 can be cut off in the groove 32, it is possible to effectively prevent the wear powder from being caught between the driving force transmission member 64 and the friction member 56. Can do.
[0041]
In addition, an adsorption electrode 31 is provided on the groove bottom surface 32a. By charging the adsorption electrode 31 to a polarity different from the charged state of the wear powder, the wear powder missing in the groove 32 can be electrostatically removed. Since dust can be collected by being attracted to the attracting electrode 31 by force, it is possible to prevent the abrasion powder adhering in the groove 32 from adhering again to the contact surface 64a of the friction member 56 or the driving force transmitting member 64. Can do.
[0042]
Therefore, it is effective to efficiently remove the wear powder adhering to the contact region S on the contact surface 64a of the drive force transmission member 64 and to allow the wear powder to be caught between the drive force transmission member 64 and the friction member 56. Therefore, a stable contact state can always be obtained, and the stage 63 can be moved with high accuracy even when the moving accuracy of about 1 μm or the positioning accuracy of 1 μm or less is required by driving the ultrasonic motor.・ Can be positioned.
[0043]
By the way, in order to obtain such an effect, it is necessary to make the width of the groove 32 smaller than the friction member 56 of the ultrasonic motor, and it is preferable that the width is preferably 0.03 mm to 1 mm. That is, when the width W of the groove 32 is equal to or larger than that of the friction member 56 of the ultrasonic motor, the contact state between the friction member 56 and the driving force transmission member 64 changes, which adversely affects the driving characteristics of the stage 63 or causes friction. This is because the wear of the member 56 is promoted, and the edge portion of the groove 32 is damaged by the friction member 56. Particularly, when the width W of the groove 32 exceeds 1 mm, the above-mentioned problem starts to appear remarkably. Conversely, when the width W of the groove 32 is less than 0.03 mm, it is difficult to provide the adsorption electrode 31 on the groove bottom surface 32a.
[0044]
When the depth L of the groove 32 exceeds 1 mm, the distance between the wear powder adhering to the vicinity of the opening of the groove 32 and the adsorption electrode 31 on the groove bottom surface 32a is too far, and the electrostatic adsorption force acting on the wear powder. Becomes too small, it becomes difficult to hold the wear powder in the groove 32. On the other hand, when the depth L of the groove 32 is less than 0.05 mm, the dust collection amount of the wear powder that has been cut off in the groove 32 is significantly reduced. For this reason, the depth L of the groove 32 is preferably 0.05 to 1 mm.
[0045]
The groove 32 may be formed at least in the contact area S with the friction member 56 of the ultrasonic motor in the contact surface 64a of the driving force transmission member 64.
[0046]
As described above, in the present embodiment, the guide device in which the movable body moves linearly has been described as an example. However, it goes without saying that the present invention can be applied to a guide device in which the movable body rotates, and further, an ultrasonic motor that drives the movable body. In addition, the present invention is not limited to the multi-mode type, and may be a single-vibration mode standing wave type or traveling wave, a multi-vibration mode mode conversion type, or a composite vibration type ultrasonic motor.
[0047]
As described above, various improvements and changes may be made without departing from the scope of the present invention.
[0048]
【Example】
(Embodiment 1) Here, abrasion powder is scraped off the guide device (reference example) shown in FIG. 1, the conventional guide device (conventional example 1) shown in FIG. 8, and the conventional guide device shown in FIG. In the experiment, each of the guide devices was driven, and the amount of wear of the friction member 56 of the ultrasonic motor 51 and the life of the guide device were examined.
[0049]
In this experiment, the vibration body 55 of the ultrasonic motor 51 has a length of 30 mm, a width of 7.5 mm, and a thickness of 3 mm, and is formed of lead zirconate titanate-based piezoelectric ceramics. Alumina ceramics was used for the friction member 56 to be joined, and its dimensions were a cylinder with a length of 4.2 mm and a diameter of 3 mm, and the contact surface was a spherical surface with a curvature radius of 7 mm.
[0050]
Further, a cross roller guide having a stroke of 100 mm was used as the guide member 62 constituting the guide device, and the stage 63 having a weight of 5 kg was moved through the guide member 62. The driving force transmission member 64 that contacts the friction member 56 of the ultrasonic motor is made of alumina ceramics, and the contact surface 64a with the friction member 56 is 0.05 μm in arithmetic mean roughness (Ra).
[0051]
In the guide device of the present invention, a copper wire having a diameter of 1 mm is used as the suction electrode 1 at a position 1 mm away from the axis of the contact area S with the friction member 56 on the contact surface 64a of the driving force transmission member 64. Was fixed to the contact surface 64a with two adhesives.
Further, by energizing the adsorption electrode 1 from the high voltage power source 2, the adsorption electrode 1 is charged with a negative charge of 1 kV.
[0052]
Moreover, the conventional guide apparatus provided with the brush for scraping off abrasion powder has arranged the brush so as to contact the contact surface 64a of the driving force transmission member 64 on both sides of the ultrasonic motor.
[0053]
Then, as a profile of the stage 13 set in advance in the control unit 68, trapezoidal control is set with a movement distance of 100 mm, an acceleration / deceleration speed of 0.03 G, and a maximum speed of 100 mm / s, and the ultrasonic motor 51 is driven at a driving frequency of 40 kHz. I did it. And the removal state of the abrasion powder after driving the stage 63 by 500 km on this condition and the wear amount of the friction member 56 were measured, respectively, and the lifetime of the guide device was measured. As for the life of the guide device, if the deviation between the actual position signal obtained from the position detecting means 67 and the reference position signal exceeds 1 μm, the stage 63 cannot be driven stably, so the deviation is 1 μm. The moving distance of the stage 63 exceeding the range is defined as the life.
[0054]
Each result is as shown in Table 1.
[0055]
[Table 1]

[0056]
As a result, the guide device of the prior art 1 that does not include the wear powder removing means has a large wear amount of the friction member 56 due to the biting of the wear powder, and the movement distance of the stage 63 is 200 km and the deviation is 1 μm. The life span was short.
[0057]
Further, in the guide device of Conventional Example 2 equipped with a brush as a means for removing wear powder, although the wear amount of the friction member 56 is small, the deviation of the deviation of 1 μm is increased in some places since the moving distance of the stage 63 has exceeded 300 km. Beyond. Examining this reason, the wear powder removed by the brush reattached to the contact surface 64a of the driving force transmission member 64, and the reattached wear powder was caught.
[0058]
On the other hand, the guide device of the present invention can attach the abrasion powder to the adsorption electrode 1, and almost no abrasion powder is present in the contact area S of the contact surface 64 of the driving force transmission member 64 with the friction member 56. Since it does not remain, the wear amount of the friction member 56 is extremely small, and even if the stage 63 is driven by 500 km, the deviation does not exceed 1 μm, so that it can be driven stably for a long time, which is excellent.
(Example 2)
Next, the same experiment as in Example 1 was performed using the guide device of the present invention shown in FIG.
[0059]
The suction member 10 constituting the suction means is bonded to a ceramic plate 12 having a length of 25 mm and a width of 30 mm as a suction electrode 11 and a polyimide tape as an insulating protective film 13 thereon. 2 were placed at both ends of the ultrasonic motor 51. However, the gap between the suction member 10 and the driving force transmission member 64 was set to 0.5 mm. Then, the adsorption electrode 11 was energized by the high-voltage power supply 2 so that the adsorption electrode 11 was charged with a negative charge of 1 kV.
[0060]
The results are as shown in Table 2.
[0061]
[Table 2]

[0062]
As a result, the guide device of the present invention shown in FIG. 2 can attach the abrasion powder adhering to the driving force transmission member 64 to the adsorption member 10, so that the friction member 56 on the contact surface 64 of the driving force transmission member 64. There is almost no wear powder remaining in the contact area S, the wear amount of the friction member 56 is extremely small, and even if the stage 63 is driven by 500 km, the deviation does not exceed 1 μm, so it is stable for a long time. I was able to drive.
Example 3
Next, an experiment similar to that of Example 1 was performed over 5000 km using the guide device of the present invention shown in FIG.
[0063]
The adsorbing member 20 constituting the adsorbing means has a conveyor structure in which a copper foil is sandwiched between polyimide sheets and a sheet-shaped adsorbing electrode 21 having a width of 30 mm is stretched by a pair of rollers 22. Two ultrasonic motors 51 are arranged at both ends. However, the gap between the suction member 20 and the driving force transmission member 64 was set to 0.5 mm. Then, the adsorption electrode 21 was energized by the high-voltage power supply 2 so that the adsorption electrode 21 was charged with a negative charge of 1 kV.
[0064]
Further, on the side opposite to the driving force transmission member 64 across the adsorption electrode 21, a resin separation pawl is pressed with a force of 50 g so that the abrasion powder scraped off by the separation pawl is collected by the collection tray. did.
[0065]
However, the adsorption electrode 21 of the adsorption member 20 was rotated once every time the stage 63 moved 500 km, and step-feeded in 10 stages.
[0066]
As a result, the wear amount of the friction member 56 of the ultrasonic motor 51 is a steady wear proportional to the moving distance of the stage 63, and no uneven wear is observed, so that the stage 63 can be driven stably during driving. In addition, since it has a function of collecting wear powder, it can be applied to a semiconductor manufacturing apparatus that requires a clean environment.
Example 4
Next, an experiment similar to that of Example 1 was performed over 5000 km using the guide device of the present invention shown in FIG.
[0067]
The grooves 32 formed on the contact surface 64a of the driving force transmission member 64 with the friction member 56 are inclined grooves 32 having an angle of 45 degrees with respect to the moving direction of the stage 63, and are formed at a pitch of 1 mm. The width W of the groove 32 is 50 μm, and the depth L of the groove 32 is 100 μm. Further, an adsorption electrode 21 was formed by depositing a silver film having a thickness of 3 μm on each groove bottom surface 32a.
[0068]
Then, the adsorption electrode 21 was energized by the high-voltage power supply 2 so that the adsorption electrode 21 was charged with a negative charge of 1 kV.
[0069]
As a result, almost no wear powder remained in the contact area S of the contact surface 64 of the driving force transmission member 64 with the friction member 56 and was held in the groove 32. Therefore, the wear amount of the friction member 56 is extremely small, and even when the stage 63 is driven by 5000 km, the deviation does not exceed 1 μm and can be driven stably for a long time. Moreover, in this embodiment, not only the wear powder adhering to the contact surface 64 of the driving force transmission member 64 but also the wear powder adhering to the friction member 56 of the ultrasonic motor 51 can be removed in the groove 32. Therefore, compared with the other embodiments of the present invention shown in FIGS. 1 to 4, the amount of wear attached to the friction member 56 can be extremely reduced, and the contact state between the driving force transmission member 64 and the friction member 56 can be reduced. Since the change can be reduced, the behavior of the stage 63 during the movement can be stabilized.
[0070]
【The invention's effect】
As described above, according to the present invention, the ultrasonic motor including the vibrating body that generates the elliptical motion, the friction member that transmits the elliptical motion of the vibrating body, and the friction member of the ultrasonic motor are in contact with each other. In a guide device using an ultrasonic motor composed of a movable body movable by friction drive as a drive source of the movable body, wear powder adhering to the contact surface of the movable body by friction drive between the ultrasonic motor and the movable body An adsorption means for collecting the dust by electrostatic force is provided. As the adsorption means, at least one adsorption electrode provided in the vicinity of the contact area of the contact surface of the movable body with the friction member of the ultrasonic motor, and the adsorption electrode Use a high-voltage power supply that applies a voltage to charge the charge, or in the vicinity of the contact area with the friction member of the ultrasonic motor on the contact surface of the movable body and between the contact surface of the movable body and the gap It comprises at least one adsorbing member having an adsorbing electrode installed and a high-voltage power source for applying a voltage to charge the adsorbing electrode of the adsorbing member, or a contact surface of the movable body A plurality of grooves having a width smaller than that of the friction member are formed in a contact area with the friction member of the ultrasonic motor in the case, and the suction electrode arranged on the bottom surface of the groove and the charge for charging the suction electrode By using what comprises a high-voltage power supply that applies a voltage to the frictional drive, it is possible to remove the abrasion powder generated by the friction drive from the contact area with the friction member on the contact surface of the movable body. Abrasion powder can be prevented from getting caught between the contact surfaces with the movable body, the movable body can be driven stably, and the accuracy during movement is 1 μm and the positioning accuracy is high. Even when high accuracy of 0.1 μm is required, the movable body can be moved and positioned with high accuracy, and furthermore, it does not pollute the surrounding atmosphere, so it is also suitable for use in a vacuum atmosphere. can do.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an example of a guide device of the present invention using an ultrasonic motor as a drive source for a movable body.
FIG. 2 is a perspective view showing another example of the guide device of the present invention using an ultrasonic motor as a drive source for the movable body.
FIGS. 3A and 3B are perspective views, partly broken, showing the structure of the suction member provided in the guide device of FIG.
FIG. 4 is a perspective view showing still another example of the guide device according to the present invention using an ultrasonic motor as a drive source of the movable body.
FIG. 5 is a perspective view showing still another example of the guide device according to the present invention in which an ultrasonic motor is used as a driving source of the movable body.
6 is an enlarged cross-sectional view of a part of a main part provided in the guide device of FIG.
7A, 7B, and 7C are plan views showing groove pattern shapes provided in the guide device of FIG.
FIG. 8 is a perspective view showing an example of a conventional guide device using an ultrasonic motor as a driving source of a movable body.
FIG. 9 is a cross-sectional view, partly broken away, showing an ultrasonic motor mounting structure in a case.
[Explanation of symbols]
1, 11, 21, 31: Electrode for adsorption 2: High-voltage power supply 10, 20: Adsorption member
12: Substrate 13: Insulating protective film 22: Roller 32: Groove 32a: Groove bottom
51: Ultrasonic motor 52: Piezoelectric ceramic body
53a, 53b, 53c, 53d: electrode film
55: Vibrating body 56: Friction member 57: Case 58: Spring
59: Spring 61: Base board 62: Guide member 63: Stage
64: Driving force transmission member 65: Linear scale 66: Measuring head
67: Position detecting means 68: Control unit 69: Driver

Claims

An ultrasonic motor comprising an oscillating body that generates an elliptical motion, a friction member that transmits the elliptical motion of the oscillating body, and a movable body that is in contact with the friction member of the ultrasonic motor and is movable by friction drive. In the guide device using the sonic motor as a drive source of the movable body, the abrasion powder adhering to the contact surface between the ultrasonic motor and the movable body is separated from the friction member of the ultrasonic motor on the contact surface of the movable body. A pair of comb-like adsorption electrodes that are positively and negatively charged are formed on a substrate made of an insulating material by providing a gap between the contact surface of the movable body and a gap in the vicinity of the contact area, and the adsorption electrodes Dust collection by electrostatic force is performed by an adsorbing means comprising at least one adsorbing member having an insulating protective film deposited thereon and a high-voltage power source for applying a voltage to the adsorbing electrode of the adsorbing member. Ultrasonic motor Guide device for a driving source of the moving object.

The insulating protective film is made of a ceramic film mainly composed of barium titanate, lead zirconate titanate (PZT), lead lanthanum zirconate titanate, lead magnesium niobate, or a mixture thereof. A guide device using the ultrasonic motor according to 1 as a driving source of a movable body.

An ultrasonic motor comprising an oscillating body that generates an elliptical motion, a friction member that transmits the elliptical motion of the oscillating body, and a movable body that is in contact with the friction member of the ultrasonic motor and is movable by friction drive. In a guide device using a sonic motor as a drive source of a movable body,
A groove having a smaller width than the friction member of the ultrasonic motor provided on the contact surface of the movable body, the wear powder adhering to the contact surface between the ultrasonic motor and the movable body, and the bottom surface of the groove An ultrasonic motor that collects dust by electrostatic force by an adsorption means comprising an adsorption electrode provided on the electrode and a high-voltage power supply that applies a voltage to charge the adsorption electrode . A guide device as a drive source.

The guide device using the ultrasonic motor as a driving source of the movable body according to claim 3, wherein the groove is formed in an oblique direction having an angle of 45 degrees with respect to the moving direction of the stage .