JP4113727B2 - Friction drive - Google Patents

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JP4113727B2
JP4113727B2 JP2002142048A JP2002142048A JP4113727B2 JP 4113727 B2 JP4113727 B2 JP 4113727B2 JP 2002142048 A JP2002142048 A JP 2002142048A JP 2002142048 A JP2002142048 A JP 2002142048A JP 4113727 B2 JP4113727 B2 JP 4113727B2
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JP2003336711A (en
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隆 小原
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Ricoh Co Ltd
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Description

【０００１】
【発明の属する技術分野】
本発明は、摩擦駆動装置に関し、さらに詳しくは、駆動軸を回転させることにより従動軸が固定された移動体を進退させる摩擦駆動装置に関するものである。
【０００２】
【従来の技術】
近年の光ディスクの高密度化にともない、より高解像の露光を実現するために、マスタリング装置の光源として、従来のレーザービームに代えて電子線等を用いた露光装置が用いられるようになり、高解像度の露光を実現する露光装置への移行に伴って真空環境への対応やより高精度な送りが必要になってきている。従来、この送り機構として、光ディスク原盤露光用のスライドテーブル装置が用いられ、静圧軸受を介してテーブルを進退自在に設けたエアスライド式が多く用いられている。また、テーブルの駆動手段としては、ボイスコイル型のリニアモータが一般的に用いられ、位置検出器として干渉レーザ測長器やリニアスケールを使用した閉ループ制御方式が採用されている。また、半導体検査装置等の静止状態を必要とするものでは、送り方向の剛性を必要とするためテーブルの駆動にボールネジ等が用いられている。
前記スライドテーブル装置の摩擦駆動機構には、駆動軸と従動軸の交差角度を鋭角とするツイストローラ方式と直角とするキャプスタン方式がある。ツイストローラ方式は、駆動軸と従動軸との間の交差角を微小にすることで、他の機構では得られない小さなリードを実現でき、高い位置決め分解能が期待できることから次世代の送り機構として期待され、文献、特許等が公開されている。
【０００３】
メカ機構として公開されている従来技術として、特開平８−１８４３６０号公報には、耐外乱性が高く、速度むらがなく、安定送りが行え、また駆動源の停止時の静止性能の向上が図れる高剛性進退装置について開示されている。これは、軸体と、この軸体を相対的に回転および進退自在に貫通させた進退部品とを備える。進退部品は、その本体内に、軸体に転接する樽形のローラを周方向に並べて複数個設ける。これらローラは、両端面でボールを介して進退部品本体と予圧板との間に回転自在に支持される。進退部品本体とローラ端面の少なくとも一方、および予圧板とローラ端面との少なくとも一方は、ボールが回転自在に嵌まる円すい面状のボール支持凹部でボールの支持を行わせる。また、予圧板をローラ側へ付勢すると共に円周方向に付勢する弾性体を設けている。
また、特開平１１−１９５２４７号公報による発明には、速度むらが生じることなく、安定した送りを行うことができ、外乱にも強く、分解能の向上が図れ、これにより高密度の書き込みを可能とした光ディスクマスタリング装置用スライドテーブル装置について開示されている。これによると、テーブルとなるスライド体を基台に対して静圧直動軸受で静圧支持し、基台に対してスライド体をスライド自在に駆動する摩擦進退駆動装置を設ける。摩擦進退駆動装置は、回転駆動される主軸と、この主軸の回りに複数個設けられて各々傾き角度を持って接するローラとを備える。そして、このローラに主軸に対する予圧を与える予圧手段を設けている。
【０００４】
また、特開平１１−１９５２４８号公報には、主軸およびこれに斜めに転接するローラを備えた摩擦進退駆動装置において、回転駆動源の回転むらの影響を少なくすると共に、回転伝達系における位相ずれを少なくし、精密な位置決めを可能とした摩擦進退駆動装置について開示されている。これは、主軸と、この主軸の外周にころがり接触しかつ主軸に対して傾き角度をもって傾斜したローラと、前記主軸の回転に起因して移動するローラと共に移動するスライド体とを有する摩擦進退駆動装置において、前記主軸を回転させる回転駆動源と、この回転駆動源の回転を駆動側軸から摩擦車への回転伝達で減速して主軸に伝達する減速機とを設けたことを特徴としている。この構成の摩擦進退駆動装置によると、主軸を回転させることにより、各ローラが主軸に対して傾き角度だけリード角を持って回転することになり、その接触部の摩擦力により、スライド体を軸方向に移動させる。この場合に、回転駆動源の回転は減速して主軸に伝達されるため、スライド体の位置決め精度に対する回転駆動源の回転むらの影響が小さくなる。また、回転駆動源の回転の伝達およびその減速は、駆動側軸と摩擦車との摩擦接触を介して行うようにしたため、バックラッシ等が生じず、これによっても精密な位置決めが行えるとしている。
また、文献；「ツイストローラ摩擦駆動装置を用いた超精密位置決めシステムの開発、著者水本他、１９９５年度精密工学会秋期大会論文集」には、空気静圧軸受により案内されたテーブルを、両端を空気静圧軸受にて支持された駆動軸と、その駆動軸線とわずかな交差角にて設けた従動軸に複数の玉軸受にて従動軸回りに回動支持されたローラを設けて、約７０μｍのリードで位置決め分解能２ｎｍを実現する旨が開示されている。
【０００５】
【発明が解決しようとする課題】
しかし、前記特開平８−１８４３６０号公報記載の発明では、駆動軸心に対して等角（１２０度）で配置されローラ端面を支持している固定板及び対向板に各々形成される円すい面状のボール支持凹部の機械的な位置誤差のために、各ローラ軸芯と駆動軸とのなす角度にばらつきが生じる。ローラ軸芯と駆動軸とのなす角度を大きく確保する場合、つまりリードＬを比較的大きく（例えば、数ｍｍ）とる場合は問題とならないが、ローラ軸芯と駆動軸とのなす角度（リードＬ）を小さくする場合、例えば、数百μｍに設定する場合は、各ローラ軸芯と駆動軸とのなす角度にばらつきがあると、駆動軸と従動軸のローラ間でリード誤差によるすべりを生じ、これが閉ループ制御の外乱となるため制御上好ましくない。これを光ディスク原盤露光等に適用すると、トラックピッチ精度等が悪くなり露光品質に悪影響を与えるといった問題が生じる。
更に、本公報による発明によると、予圧板をローラ側へ付勢すると共に、円周方向に付勢する弾性体を設ける構成をとっているため、ローラの軸体に対する予圧量の調整は、進退部品本体に設けたネジ部を有する穴部と予圧板に設けた穴部を連通させた位置として、その連通穴部に弾性体を設けて進退部品本体に設けたネジ部のイモネジを締めることによる弾性体の圧縮変形力を利用している。この構成の場合、ローラの軸体に対する現在予圧量が定量的に確認できないので、適正な予圧量にするのに試行錯誤が必要となり、又、ローラや軸体の磨耗による経年変化に伴う予圧の再調整も困難となり、部品交換時の予圧量再現性もなく組立性が悪くなる。
【０００６】
また、特開平１１−１９５２４７号公報では、基台に固定される静圧直動軸受固定部の真直と摩擦進退駆動装置主軸の真直との間に誤差を生じた状態で組み立てられた場合、スライド体が送り方向に動作すると、予圧をかけられて固定されているだけで剛性が最も低いローラと主軸間で、その真直誤差を吸収することになるので、ローラの主軸に対する予圧量が移動位置とともに変化してしまう。つまり、駆動軸と一つのローラ間に働く駆動軸方向の駆動力は、駆動軸外周とローラ間の動摩擦係数をμ、予圧をＮとすると、Ｆ＝μＮとなる。従って、各々のローラと駆動軸外周で発生する駆動力にもばらつきを生じ、更に各々の駆動力にもばらつきを生じるため、各ローラ軸芯と駆動軸とのなす角度のばらつきと相乗して駆動軸と従動軸のローラ間ですべりを生じ、これが、閉ループ制御の外乱となるため、光ディスク原盤露光等に適用するとトラックピッチ精度等が悪くなり露光品質に悪影響を与えるといった問題がある。
更に、本公報によると、スライド体を基台に対して静圧直動軸受で静圧支持し、又、前記文献では、空気静圧軸受により案内されたテーブルを、両端を空気静圧軸受にて支持する構成としているが、このような静圧軸受は非常に高価であり装置コストが高くなるといった問題がある。
本発明は、かかる課題に鑑み、前記問題点を生じることなく、高精度送りを実現できる摩擦駆動装置、特に光ディスク原盤露光装置用送りステージを提供することを目的とする。
【０００７】
【課題を解決するための手段】
本発明はかかる課題を解決するために、請求項１は、固定されたベースと、該ベース側に回転自在に支持された駆動軸と、該駆動軸の外径位置に所定の傾斜角度をもって円周方向に等角配置された複数の従動軸と、該複数の従動軸により夫々回転自在に支持され且つ前記駆動軸の外周にころがり接触するローラと、前記駆動軸の回転に伴って駆動軸の軸方向に移動すると共に前記従動軸を支持する移動体と、該移動体の送り位置を検出する位置検出手段と、を備えた摩擦駆動装置であって、前記複数の従動軸の内の少なくとも一つの従動軸は軸線方向に移動不能に前記ローラを支持し、他の従動軸はその軸線方向に移動可能に前記ローラを支持する移動手段及びその移動量を検出する移動量検出手段と、を備え、前記各従動軸を回動自在に支持する軸受と、前記軸受の中心である回動支持点を支点として該従動軸の他端を駆動軸外周から離間させる方向に押圧する第１の弾性体及び前記駆動軸外周の接線方向に押圧する第２の弾性体とを備え、前記回動支持点を挟んだ前記ローラと反対側の従動軸端部に対応する前記移動体部分に固定され、前記駆動軸の軸線と直交する方向且つ前記第１の弾性体の押圧力による前記回動支持点周りのモーメント力を相殺する方向に前記従動軸を押圧する第１の押圧手段と、前記駆動軸外周の接線方向且つ前記第２の弾性体の押圧力による前記回動支持点周りのモーメント力を相殺する方向に前記従動軸を押圧する第２の押圧手段と、前記各構成要素の制御を行う制御部と、前記制御部の指令により前記第１の押圧手段を押圧／開放し、前記ローラを前記他の従動軸の軸線方向に移動／固定する第１の出力手段と、前記駆動軸の１回転当たりの原点検出信号と前記ローラの移動量検出手段の出力信号に基づいて、前記他の従動軸に対する、前記少なくとも一つの従動軸の傾き角度誤差を算出する角度誤差算出手段と、前記角度誤差算出手段により算出された角度誤差に相当する出力信号を現在の印加信号から増減した補正信号を前記第２の押圧手段に印加する第２の出力手段を有する角度調整手段と、を備えたことを特徴とする。
本発明は、光ディスク原盤を露光する際に、光ディスク原盤を支持して回転させたり、径方向移動させるための光ディスク原盤露光装置用送りステージに用いられる摩擦駆動装置に関するものであり、高精度送りを実現できるものである。
この発明では、駆動軸の外周に複数の従動軸の一端を球面軸受にて支持すると共に他端を弾性体による自由支持とし、球面軸受の回動支持点を挟んでローラと反対側の従動軸の他端を第１の押圧手段により離間方向へ押圧し、且つ第２の圧電素子により駆動軸接線方向に押圧し、更に制御部により制御される第１の出力手段と、固定した従動軸に対する傾き角度誤差を算出する角度誤差算出手段と、角度調整手段と、を設けて、加工、組み付け誤差等による機械的な位置誤差のために生じる各従動軸と駆動軸とのなす交差角度のばらつきを補正できるようにしている。
かかる発明によれば、加工、組み付け誤差等による機械的な位置誤差のために生じる各従動軸と駆動軸とのなす交差角度のばらつきを補正できるようにしているので、各ローラ軸芯と駆動軸とのなす角度が精密に設定され、駆動軸と各従動軸のローラ間でリード誤差によるすべりを発生せず、安定した送り制御が実現でき、送り精度の向上が図れる。
【０００８】
請求項２は、請求項１において、前記移動手段は、前記他の従動軸の外周に配置されると共に外周に軸受を介して前記ローラを備え、且つ該ローラの軸方向両端部の内周面と前記他の従動軸の外周面との間にすべり軸受を形成する移動リングと、前記移動リングに外周部が固着され、且つ前記他の従動軸に内周部が固着された円盤状の弾性板と、前記他の従動軸の軸線と直交する方向に設けられた少なくとも１つ以上の貫通穴内に嵌合する複数の鋼球と、前記他の従動軸の一端面から軸線方向に同軸状に設けられ且つ前記貫通穴と連通する穴部と、前記穴部内に軸方向移動可能に支持されて、テーパ状の先端部にて前記複数の鋼球と接する突き出しピンと、を備えていることを特徴とする。
かかる発明によれば、移動手段は、外周にローラが設けられ、移動リングの一端と対向する従動軸の一端に内周部が固着された円盤状の弾性板と、従動軸に設けられた少なくとも１つ以上の貫通穴に嵌合し、先端部がテーパ状の突き出しピンのテーパ部に接触する複数の鋼球を設けた構成としており、単純な構成でローラの移動／固定とその移動量検出が可能となり装置コストが安価となる。
請求項３では、請求項１又は２において、前記移動量検出手段は、前記円盤状の弾性板の内外周間での半径方向のひずみを検出するひずみゲージと、抵抗値変化を検出するブリッジ回路と、該ブリッジ回路の信号を増幅する増幅器と、を備えたことを特徴とする。
かかる発明によれば、移動量検出手段は、ひずみを検出するひずみゲージとブリッジ回路と増幅器から構成しており、単純な構成でローラの移動／固定とその移動量検出が可能となり装置コストが安価となる。
【０００９】
請求項４は、前記第１の出力手段は、一定電圧を発生する定電圧回路と、一方の端子を０Ｖ、他方の端子に前記定電圧回路の出力信号が接続され外部信号によりＯＮ／ＯＦＦする切換スイッチと、第１の押圧板の第１の変形部に設けた第１の変形量測定手段と、前記切換スイッチの出力信号である押圧伸縮設定信号と前記第１の変形量測定手段の出力信号である現在押圧伸縮量とを比較してサーボ制御する第１のサーボ制御手段と、を備えたことを特徴とする。
かかる発明によれば、第１の出力手段を、定電圧回路と、外部信号によりＯＮ／ＯＦＦする切換スイッチと、第１の押圧板に設けた第１の変形量測定手段と、切換スイッチの出力信号と第１の変形量測定手段の出力信号とを比較してサーボ制御する第１のサーボ制御手段を設けたことにより、ローラの駆動軸外周への押圧（予圧）動作と各従動軸と駆動軸との交差角度を補正する角度補正動作を再現性よく行えるので、更に、安定した送り制御が実現でき、送り精度の向上がはかれる。
請求項５は、前記第２の出力手段は、ＣＰＵからのデジタル信号をアナログ信号に変換するＤ／Ａ変換器と、前記第２の押圧手段に設けた第２の変形部に設けた第２の変形量測定手段と、前記Ｄ／Ａ変換器の出力信号である押圧伸縮設定信号と前記第２の変形量測定手段の出力信号である現在押圧伸縮量とを比較してサーボ動作を行う第２のサーボ制御手段と、を備えたことを特徴とする。
かかる発明によれば、第２の出力手段は、Ｄ／Ａ変換器の出力信号と第２の変形量測定手段の出力信号とを比較してサーボ動作を行う第２のサーボ制御手段を設けているので、ローラの駆動軸外周への押圧（予圧）動作と各従動軸と駆動軸との交差角度を補正する角度補正動作を再現性よく行えるので、更に、安定した送り制御が実現でき、送り精度の向上がはかれる。
【００１０】
請求項６は、前記角度調整手段は、前記移動体に固定された第１の固定板と、第１の固定板に設けた第１の案内部に両側面が嵌合するよう設けられた第１の押圧板と、前記移動体に固定され且つ前記従動軸を押圧して位置調整するために前記第１の固定板に設けた第１の調整ネジ及び前記第１の押圧板に設けた雌ネジ部と、前記移動体に支持され且つ前記従動軸を前記駆動軸外周の接線方向に押圧すると共に前記第１の固定板に設けた第２の案内部に嵌合するよう設けられた第２の押圧板と、を備え、前記従動軸を前記駆動軸外周の接線方向に押圧するために前記第１の固定板に設けた第２の調整ネジと、前記第２の押圧板の後端側面と、によって、前記従動軸を前記駆動軸外周の接線方向に押圧して位置調整可能となるように構成されていることを特徴とする。
かかる発明によれば、角度調整手段は、第１の固定板の第１の案内部に嵌合するよう設けられた第１の押圧板と、第１の固定板に設けた調整ネジと第１の押圧板に設けた雌ネジ部によって位置調整可能となるように設けられ、かつ、第１の固定板の第２の案内部に嵌合するよう設けられた第２の押圧板と、第１の固定板に設けた調整ネジと第２の押圧板によって従動軸を駆動軸外周の接線方向に押圧する方向に位置調整可能となるように設けて、大きな交差角度でも上記角度補正動作が行えるようにしているので、広いリード条件範囲において安定した送り制御が実現でき、送り構成要素としての汎用性を高くすることができる。
請求項７は、前記第１の出力手段は、電圧を変更可能とした構成の可変電圧回路と、一方の端子を０Ｖとし且つ他方の端子に前記可変電圧回路の出力信号が接続され外部信号によりＯＮ／ＯＦＦする切換スイッチと、前記第１の押圧板と前記回動支持点とローラ間にあって、前記従動軸の押圧方向への変形量を検出する第３の変形量測定手段と、前記切換スイッチの出力信号である押圧設定信号と前記第３の変形量測定手段の出力信号である現在押圧量とを比較してサーボ制御する第３のサーボ制御手段と、を備えたことを特徴とする。
かかる発明によれば、第１の出力手段は、可変電圧回路とグランドとを外部信号によりＯＮ／ＯＦＦする切換スイッチの出力信号である押圧設定信号と第３の変形量測定手段の出力信号である現在押圧量とを比較してサーボ制御する第３のサーボ制御手段を設けているので、ローラの駆動軸に対する予圧量を従動軸の変形量に置換した信号で予圧サーボをしているので、適正な予圧条件に瞬時に設定でき、ローラや駆動軸の磨耗による経年変化に伴う予圧の再調整も容易となり、部品交換時の予圧量再現性も良好となり組立性の向上が図れる。
【００１１】
請求項８は、前記第１の出力手段は、ＣＰＵからのデジタル信号をアナログ信号に変換する１つのＤ／Ａ変換器と、前記第３の変形量測定手段と、前記１つのＤ／Ａ変換器の出力信号である押圧設定信号と第３の変形量測定手段の出力信号である現在押圧量とを比較してサーボ制御する第４のサーボ制御手段と、を備えていることを特徴とする。
かかる発明によれば、第１の出力手段は、一つのＤ／Ａ変換器と、従動軸の外周部に従動軸の押圧方向の変形量を検出する第３の変形量測定手段と、Ｄ／Ａ変換器の出力信号と第３の変形量測定手段の出力信号とを比較してサーボ制御する第４のサーボ制御手段を設けて、ローラの駆動軸に対する予圧量を従動軸の変形量に置換した信号で予圧サーボをしているので、適正な予圧条件に瞬時に設定でき、ローラや駆動軸の磨耗による経年変化に伴う予圧の再調整も容易となり、部品交換時の予圧量再現性も良好となり組立性の向上が図れる。
請求項９は、前記第１の出力手段は、複数の圧電素子への押圧設定信号を独立に与えるためにＣＰＵからのデジタル信号をアナログ信号に変換する複数のＤ／Ａ変換器と、第３の変形量測定手段と、前記複数のＤ／Ａ変換器の出力信号である押圧設定信号と前記第３の変形量測定手段の出力信号である現在押圧量とを比較してサーボ制御する第５のサーボ制御手段と、を備えていることを特徴とする。
かかる発明によれば、第１の出力手段は、複数のＤ／Ａ変換器の出力信号と第３の変形量測定手段の出力信号とを比較してサーボ制御する第５のサーボ制御手段を設けて、ローラの駆動軸に対する予圧量を従動軸の変形量に置換した信号で予圧サーボを行い、かつ各々の第１の押圧手段への押圧設定値を独立に与えるようにしているので、ベースに固定される案内機構の固定部である支柱の送り方向真直と駆動軸の送り方向真直に誤差を生じて組み立てが行われても、移動体が送り方向に動作した時の組立誤差による予圧変動を生じることがなく、各々のローラと駆動軸外周で発生する駆動力にもばらつきを発生しないので、長ストロークの駆動でも安定した送り動作が実現でき送り制御精度及び組立性の向上がはかれるとともに簡便な案内機構で構成できるので装置が安価となる。
請求項１０は、前記従動軸は、前記第１の押圧手段の押圧点と前記回動支持点間距離をＬ１、前記回動支持点とローラ間距離をＬ２とした時に、Ｌ２＞Ｌ１の条件を満足する第３の変形量測定手段変位拡大機構を形成していることを特徴とする。
かかる発明によれば、従動軸は、第１の押圧手段に用いる圧電素子の伸縮量が小さくても大きな押圧ストロークが得られるので、駆動軸回りに配置する機構を小さくでき、装置の小型化が図れる。
【００１２】
【発明の実施の形態】
以下、本発明を図に示した実施形態を用いて詳細に説明する。但し、この実施形態に記載される構成要素、種類、組み合わせ、形状、その相対配置などは特定的な記載がない限り、この発明の範囲をそれのみに限定する主旨ではなく単なる説明例に過ぎない。
図１は、本発明の第１の実施形態に係る摩擦駆動装置の制御系構成図である。図１（ａ）は、摩擦駆動装置の上面図であり、（ｂ）はその右側面図であり、（ｃ）は部分断面図である。この摩擦駆動装置は、例えば光ディスク用原盤露光装置に用いる送り装置に使用される。
図示しない除振機構、例えば、空気圧によるサーボマウンタ上に設けたベース９０上には、送り方向と直交する方向に離間配置されて基端部をベース９０に固定した支柱８９（８９ａ、８９ｂ）が立設されており、各支柱８９の上端部には、例えば球体、円筒ローラ等を送り方向に配置したころがり軸受１４（１４ａ、１４ｂ、案内機構）を介して移動体１３が送り方向へ移動可能に支持されている。
【００１３】
移動体１３には、上部に加工対象物のとしての光ディスク原盤を支持するターンテーブル１８を固定し、図示しない外部より供給される圧縮空気によりラジアル、スラスト方向に静圧浮上するエアスピンドル１９が内部に配置されており、エアスピンドル１９には回転駆動モータ２０を介して、その出力が一周（３６０度）を数千に等分割されたＡ相、Ｂ相パルスと、一周に１回発生するＺ相パルスとから構成される光学式ロータリーエンコーダ（１）２１が固定されており、図示しない外部からの回転駆動モータ２０への通電信号により回転自在に構成されている。
また、移動体１３の送り方向より見て左側端部の下部には、例えば、送り方向における所定の分解能を提供するＡ相、Ｂ相パルスから構成される光学式リニアエンコーダ等の送り方向の位置を計測する受光部１５ａと、スケール１５ｂとから構成される位置検出手段１６が設けられている。スケール１５ｂは取付板（１）１５ｃを介して移動体１３に固定されており、受光部１５ａは取付板（２）１７を介してベース９０側に固定されている。図１では、スケール１５ｂが移動体１３に固定され、受光部１５ａがベース９０に固定されているが、受光部１５ａを移動体１３に固定し、スケール１５ｂをベース９０に固定する構成としても構わない。
さらに移動体１３から送り方向へ突出する突出部１３ａの下部には、横方向へ延びる駆動軸１を支持する穴部２２ａ、２３ａを設けた第１の固定板２２及び第２の固定板２３の上端部が夫々固定的に支持されている。さらに駆動軸１の外周にころがり接触するローラ８ａ〜８ｃを、例えばアンギュラ軸受等を対向したころがり軸受（２）９ａ〜９ｃを介して同心状に設けた３つの従動軸７ａ〜７ｃが駆動軸１の軸線に対して円周方向に等角配置されている。
【００１４】
図２（ａ）は図１のＡ−Ａ’断面を表し、（ｂ）はＢ−Ｂ’断面を表し、（ｃ）はＣ−Ｃ’断面を表す。また、図２（ｄ）は弾性体部の詳細図である。各従動軸７ａ〜７ｃの右側端部は夫々、図２（ｂ）Ｂ−Ｂ’の断面図にも示すように、第２の固定板２３に周方向に所定のピッチにて設けた各凹部２３Ａ、２３Ｂ、２３Ｃ内に、夫々、駆動軸１の軸線に対して円周方向に等角となるように配置されて支持されている。更に、各従動軸７ａ〜７ｃの外周に対して夫々回転自在に軸支されたローラ８ａ〜８ｃを駆動軸１の外周から離間させる方向（離間方向）に押圧する球３５ｄ〜３５ｆをコイルスプリング等の３つの第１の弾性体３５ａ〜３５ｃ（押圧端部に配置される）により押圧する構成を備えた第３の押圧板３６ａ〜３６ｃと（図２（ｄ）参照）、各従動軸７ａ〜７ｃを駆動軸１の外周接線方向に押圧する球３８ｄ〜３８ｆをコイルスプリング等の３つの第２の弾性体３８ａ〜３８ｃ（押圧端部に配置される）により押圧する構成を備えた第４の押圧板４０ａ〜４０ｃと、が設けられている。このように、従動軸７ａ〜７ｃの右側端部を、弾性付勢された各球により自由支持する構成となっている。なお、本発明の実施形態では、第２の固定板２３と分離された第３の押圧板３６ａ〜３６ｃと第４の押圧板４０ａ〜４０ｃに夫々第１の弾性体３５ａ〜３５ｃ、第２の弾性体３８ａ〜３８ｃを設けているが、第２の固定板２３に各弾性体を直接設けてもかまわない。
【００１５】
また、第１の固定板２２の右側面には、図１（ｃ）の部分断面図、及び図２（ａ）、（ｃ）の断面図に示すように、従動軸７ａ〜７ｃの左側端部外周とその内周が嵌合する球面軸受等の軸受２６ａ〜２６ｃが、駆動軸１の軸線に対して円周方向に等角配置されて固定されており、従動軸７ａ〜７ｃは、その軸受２６ａ〜２６ｃの回動支持点２４ａ〜２４ｃを含む平面内に回動可能な構成となっている。さらに、第１の固定板２２の凹部２２Ａ、２２Ｂ、２２Ｃには、回動支持点２４ａ〜２４ｃを挟んだ各ローラ８ａ〜８ｃとは反対側に、図２（ａ）、図４（ａ）に示すような第１の圧電素子２７ａ〜２７ｃを伸縮方向に固定する。即ち、第１の押圧手段４７ａ〜４７ｃと第２の押圧手段４８ａ〜４８ｃが、駆動軸１の軸線に対して円周方向に等角配置されて固定されている。
即ち、第１の押圧手段４７ａ〜４７ｃは、駆動軸１の軸線と直角方向で第１の弾性体３５ａ〜３５ｃの押圧力による回動支持点２４ａ〜２４ｃ周りのモーメント力を相殺する方向に、従動軸７ａ〜７ｃを押圧するための第１の圧電素子２７ａ〜２７ｃを伸縮方向に固定し、従動軸７ａ〜７ｃを押圧する側の固定端に第１の変形部２８ｄ〜２８ｆを設けた構成を備えている。また、第２の押圧手段４８ａ〜４８ｃは、駆動軸１外周の接線方向で第２の弾性体３８ａ〜３８ｃの押圧力による回動支持点２４ａ〜２４ｃ周りのモーメント力を相殺する方向に従動軸７ａ〜７ｃを押圧する図４（ｂ）に示すような第２の圧電素子３１ａ〜３１ｃを伸縮方向に固定し、従動軸７ａ〜７ｃを押圧する側の固定端に第２の変形部３２ｄ〜３２ｆを設けた構成を備えている。
【００１６】
さらに駆動軸１の右側端部は第一の段付部１ａになっており、その外周はベース９０に固定され且つ上部に段付の貫通穴を設けたハウジング１０の左側円筒穴部１０ａ内に同心状にその外輪を固定されたアンギュラ軸受等の対向するころがり軸受３２の内周部に嵌合しており、駆動軸１に設けたネジ部ところがり軸受３２の内周部が軸受止め３にて固定されている。さらに、駆動軸１の第二の段付部１ｂの外周は、ハウジング１０の右側円筒穴部に同心状に固定され、一般的にその出力が一周を数千等に分割したＡ相、Ｂ相パルスと一周に１回発生するＺ相パルスから構成されるロータリーエンコーダ（２）６を固定した送り駆動モータ５の駆動軸とがオルダム式等のカップリング４により連結されている。さらに、駆動軸１の左側端部に位置する段付部１ｃの外周は、ベース９０に固定され且つ上部に貫通穴が設けられ、その貫通穴と同心状に例えば、深溝玉軸受等のころがり軸受（４）１２の外輪が軸心方向に移動可能となるように固定されたころがり軸受（４）１２の内輪に嵌合する構成となっている。
以上の構成により、図示しない第１の圧電素子２７ａ〜２７ｃ、第２の圧電素子３１ａ〜３１ｃのリード線端末より適当な通電電圧を第２の圧電素子３１ａ〜３１ｃ、第１の圧電素子２７ａ〜２７ｃの順に印加すると、図１８の点線に示すように駆動軸１の軸心と従動軸７ａ〜７ｃの軸心はある角度θで交差した状態でローラ８ａ〜８ｃの外周と駆動軸１の外周がころがり接触する。この状態で、図示しない送り駆動モータ５の端末より通電すれば、ローラ８ａ〜８ｃの外周と駆動軸１の外周の接触点は螺旋状に移動し、移動体１３が送り方向に移動自在となる。この時、従動軸７ａ〜７ｃ自身は回転せず、ころがり軸受（２）９ａ〜９ｃの外輪が回転する外輪回転となる。又、駆動軸１が１回転当たりに移動体１３を移動する移動量Ｌリード量は、駆動軸１の外形寸法をＤとすれば、
Ｌ＝π・Ｄ・ｔａｎθ −−−−−−−−（１）
θ＝ｔａｎ -1 ｛Ｌ／π・Ｄ｝−−−−−−−（２）
で表され、例えば、Ｄ＝３０ｍｍ条件での交差角度とリード量Ｌの関係は図１７の両対数グラフに示すように線形である。
【００１７】
さらに図３に示すように一つの従動軸７ａには、従動軸７ａの軸線方向に移動不能に固定され且つ回転自在に支持されたローラ８ａが設けられ、他の従動軸７ｂ、７ｃには、軸方向両端部の内周面と従動軸７ｂ、７ｃの外周面との間にすべり軸受９８（９８ｂ、９８ｃ）を支持した移動リング９１（９１ｂ、９１ｃ）が従動軸７ｂ、７ｃと同心状に設けられている。更に、移動リング９１の軸方向片端には、その外周部が固着され、且つその片端と対向する従動軸７ｂ、７ｃの片端に内周部が固着された円盤状の弾性板９２（９２ｂ、９２ｃ）が設けられて移動手段９７（９７ｂ、９７ｃ）が構成されており、ローラ８ｂ、８ｃが従動軸７ｂ、７ｃの軸線方向に移動可能な構成としている。
さらに、各従動軸７ｂ、７ｃには、その軸線と直交する方向に貫通穴９９が設けられると共に、図中右端部より形成された同心状の穴部（軸穴）７ｂ−１、７ｃ−１が夫々貫通穴９９に連通するように設けられている。この穴部内には、穴部の内壁と外周が略嵌合し（遊嵌し）且つ図示しないＯリング等を外周に備え先端部がテーパ状の突き出しピン９４（９４ｂ、９４ｃ）を、軸方向へ進退可能に支持する。そして、例えば圧縮コイルバネ９６（９６ｂ、９６ｃ）により突き出しピン９４を軸方向外側へ弾性付勢する。さらに貫通穴９９に嵌合し、突き出しピン９４の内側端部に位置するテーパ部に接触する複数の鋼球（ボールベアリング）９５が設けられている。この構成にて、従動軸７ｂ、７ｃの右端部から軸方向に形成した前記穴部の開口である給気口より、圧縮空気等を穴部内に供給すれば、突き出しピン９４が従動軸７ｂ、７ｃの軸線左方向に移動しテーパ部にて接触している鋼球９５が従動軸７ｂ、７ｃの軸線と直交する方向に移動して、従動軸を包囲する移動リング９１の内周面を押圧し、移動リング９１と従動軸７ｂ、７ｃとが固定される。
さらに、円盤状の弾性板９２の内外周間でその半径方向のひずみを検出するひずみゲージ９３（９３ｂ、９３ｃ）が設けられており、各ひずみゲージの図示しないリード線端末は、図５に示すブリッジ回路１０１（１０１ｂ、１０１ｃ）に夫々接続されており、ブリッジ回路１０１の出力信号は増幅器１０２（１０２ｂ、１０２ｃ）に接続され、ローラ８ｂ、８ｃの移動量を各弾性板９２（９２ｂ、９２ｃ）の変形量として検出できるように構成されており、全体として移動量検出手段１００を構成している。
【００１８】
次に、従動軸７ａ〜７ｃの角度を調整する制御ブロック図について図５を用いて説明する。割り込み用信号としてロータリーエンコーダ２６の一周毎に１回発生するＺ相パルス信号４９の信号線が接続されたＣＰＵ５８には、その動作プログラムを書き込むＲＯＭ６０とデータを記憶するＲＡＭ６１とが接続され、Ｚ相パルス信号４９の立ち上がりをトリガー信号として移動量検出手段１００のアナログ出力信号をデジタル信号に変換するＡ／Ｄ変換器１０３（１０３ｂ、１０３ｃ）が接続されている。又、その出力信号が第２の圧電素子３１ａ〜３１ｃの図示しない端末に接続される駆動アンプｄ５７ｄ、ｅ５７ｅ、ｆ５７ｆに接続され、デジタルデータをアナログ信号に変換するＤ／Ａ変換器ａ６３ａ、ｂ６３ｂ、ｃ６３ｃが接続されている。ここで、Ｄ／Ａ変換器ａ６３ａ、ｂ６３ｂ、ｃ６３ｃと駆動アンプｄ５７ｄ、ｅ５７ｅ、ｆ５７ｆにて第２の出力手段５０を構成している。さらに、その出力信号が第１の圧電素子２７ａ〜２７ｃの図示しない端末に接続される駆動アンプａ５７ａ、ｂ５７ｂ、ｃ５７ｃと、固定の定電圧を出力する定電圧回路５５（５５ａ、５５ｂ）の出力信号が外部信号によってＯＮ／ＯＦＦできるスイッチ１、２、３（５６ａ〜５６ｃ）を介して駆動アンプａ５７ａ、ｂ５７ｂ、ｃ５７ｃの入力信号として接続されて構成した第１の出力手段６４のスイッチ１、２、３（５６ａ〜５６ｃ）の駆動信号がＣＰＵ５８に接続されており、又、その出力信号が電磁弁１０４（１０４ｂ、１０４ｃ）に接続され、入力に固定の定電圧を出力する定電圧回路５５（５５ａ、５５ｂ）の出力信号が外部信号によってＯＮ／ＯＦＦできるスイッチ４、５（５６ｄ、５６ｅ）の駆動信号が接続されている。さらに、リード量データＬとその設定許容誤差データεを入力するデータ入力部５９が接続されており、全体で角度調整手段５１を構成している。
【００１９】
以上の回路構成による動作を図６の動作フロー図にて説明する。予め入力されたリード量データＬとその設定許容誤差データεを読み込んだ後（Ｓ１）、図示しない装置全体のホストコンピュータからの指令信号８８ａを待った後（Ｓ２）、ホストコンピュータからの指令信号８８ａがＯＮされると、角度算出手段６５にて上記式▲２▼にもとづいて交差角度θの計算が行われた後（Ｓ３）、スイッチ４、５６ｄ、スイッチ５、５６ｅの駆動信号がＯＮされて電磁弁１０４（１０４ｂ、１０４ｃ）が動作して従動軸７ｂ、７ｃの各穴部７ｂ−１、７ｃ−１の右端開口部としての給気口より圧縮空気等が供給され突き出しピン９４が移動して移動リング９１と従動軸７ｂ、７ｃが固定され、スイッチ１、２、３（５６ａ〜５６ｃ）の駆動信号がＯＦＦされて第１の圧電素子２７ａ〜２７ｃへの信号がＯＦＦされて押圧手段（１）４７ａ〜４７ｃが開放される（Ｓ６）。つづいて、Ｄ／Ａ変換器６３に対して上記角度算出手段６５によって計算された交差角度θに相当するデジタルデータが送出され（Ｓ７）、駆動アンプ５７を介して圧電素子（２）３１に計算された交差角度θに相当する変位電圧が印加され押圧手段（２）４８が従動軸７を駆動軸１外周の接線方向に押圧し、その後、スイッチ（１）５６ａへの駆動信号がＯＮされて圧電素子（１）２７ａへ適当な電圧に設定された定電圧回路５５の出力信号が駆動アンプ５７を介して通電され、押圧手段（１）４７が従動軸７を押圧する（Ｓ８）。その後、スイッチ４、５（５６ｄ、５６ｅ）の駆動信号がＯＦＦされて（Ｓ９）、移動リング９１と従動軸７ｂ、７ｃが開放され、この状態で、送り駆動モータ５が回転開始し（Ｓ１０）、Ｚ相パルス信号４９の立ち上がりをトリガー信号としてローラ８ｂの移動量ＸｂがＡ／Ｄ変換器１０３ｂにて取り込まれ（Ｓ１１）、ここで、従動軸７ａの設定リード量に対して従動軸７ｂの実リード量が大きい場合はＸｉ＞０、小さい場合Ｘｉ＜０となる。その後、相対リード量を算出する相対リード量算出手段６６にて相対リード量Ｌｂが求められ、相対角度誤差Δθｂを算出し、ローラ８ｂの移動量Ｘｂが設定された設定許容誤差データε以下であればその角度データθｂをＲＡＭ６１に記憶し、大きい場合は、差分データΔθｂが０よりも大きい場合は設定された角度データからΔθｂを減じ、又、Δθｂが０よりも小さい場合は設定された角度データにΔθｂを加える電圧補正手段６７にて逐次繰り返して行われ、ε≧Ｘｉとなるまで行われる（Ｓ１２）。
【００２０】
上記フロー中のステップＳ５は、サブルーチン（ＳＵＢ）になっており、上記の動作がｂ、ｃの順で行われ全てが完了するとスイッチ１、２、３（５６ａ〜５６ｃ）の駆動信号がＯＦＦされて圧電素子（１）２７ａ〜２７ｃへの信号がＯＦＦされて第１の押圧手段４７ａ〜４７ｃが開放され、スイッチ４、５（５６ｄ、５６ｅ）の駆動信号がＯＮされて電磁弁１０４（１０４ｂ、１０４ｃ）が動作して従動軸７ｂ、７ｃの右端部に設けた給気口より圧縮空気等が供給され突き出しピン９４が移動して移動リング９１と従動軸７ｂ、７ｃが固定され、記憶された角度データθａ、θｂ、θｃに相当するデジタルデータがそれぞれＤ／Ａ変換器ａ６３ａ、ｂ６３ｂ、ｃ６３ｃに出力された後、スイッチ１、２、３（５６ａ〜５６ｃ）の駆動信号がＯＮされて圧電素子（１）２７ａ〜２７ｃへの信号がＯＮされ第１の押圧手段４７ａ〜４７ｃが押圧し、スイッチ４、５（５６ｄ、５６ｅ）の駆動信号がＯＦＦされて、移動リング９１と従動軸７ｂ、７ｃが開放され、再度Ｚ相パルス信号４９の立ち上がりをトリガー信号としてローラ８ｂ、８ｃの移動量Ｘｂ、ｃがＡ／Ｄ変換器１０３にて取り込まれ、その相対誤差データである移動量Ｘｂ、ｃが設定された設定許容誤差データε以下であることを確認し、スイッチ４、５（５６ｄ、５６ｅ）の駆動信号がＯＮされて電磁弁１０４が動作して従動軸７ｂ、７ｃの右端部に設けた給気口より圧縮空気等が供給され突き出しピン９４が移動して移動リング９１と従動軸７ｂ、７ｃが固定し、図示しないホストコンピュータへ設定完了信号８８ｂをＯＮにして動作完了する（Ｓ１３）。
以上の構成によれば、加工、組み付け誤差等による機械的な位置誤差のために各従動軸心と駆動軸とのなす交差角度にばらつきを生じても各従動軸の角度位置を補正できる。
【００２１】
次に、本発明の第２、３の実施形態について図７乃至図９に基づいて説明する。実施形態１と説明が重複する部分については、説明を省略する。実施形態１の構成要素である第１の圧電素子２７ａ〜２７ｃの印加電圧に対する変位量の関係は、圧電素子の印加電圧と変位量特性との関係を示す図１４に示すように、一般的に履歴特性をもっている。つまり、印加電圧を上げるとそれに伴って変位量も増加するが、その状態から印加電圧を下げても元の軌跡を辿らないで、印加電圧０の状態で変位量Ｄｐが残ってしまう。そのため第１の圧電素子２７ａ〜２７ｃへの印加電圧が比較的小さい場合は、第１の押圧手段４７ａ〜４７ｃの開放時の残変位量Ｄｐは非常に小さいので問題とならないが、印加電圧が比較的大きい場合、言い換えるとローラ８ａ〜８ｃの駆動軸１に対する押圧量（これを一般的に予圧と呼ぶ）を大きくすると残変位量Ｄｐが大きくなるため完全に開放できない場合を生じる。
そこで、実施形態２では、図７（ａ）に示すように、第１の押圧板２８ａ〜２８ｃの第１の変形部２８ｄ〜２８ｆに例えば、抵抗値の変化によってその変形量を検出する歪みゲージ等の第１の変形量測定手段３０ａ〜３０ｃを設け、その第１の変形量測定手段３０（３０ａ〜３０ｃ）の出力信号と定電圧回路の設定電圧を比較してサーボ制御する構成としている。
【００２２】
図８にそのブロック図を示す。定電圧回路５５の出力信号は、駆動信号がＣＰＵ５８に接続され、ＯＮ時に定電圧回路５５の出力信号に接続し、ＯＦＦ時に回路の０ＶＧＮＤに接続するスイッチ４、５、６（６８ａ〜６８ｃ）を介して差動アンプａ６８ａ、ｂ６８ｂ、ｃ６８ｃに接続されており、又、第１の変形量測定手段３０ａ〜３０ｃの出力信号は抵抗値変化を検出するブリッジ回路ａ７３ａ、ｂ７３ｂ、ｃ７３ｃに接続され、その出力信号は微少信号を増幅する増幅器ａ７２ａ、ｂ７２ｂ、ｃ７２ｃに入力され、その出力信号は、上記差動アンプａ６８ａ、ｂ６８ｂ、ｃ６８ｃに入力され、差動アンプａ６８ａ、ｂ６８ｂ、ｃ６８ｃの内部でスイッチ４、５、６（６８ａ〜６８ｃ）の端部に接続されている定電圧回路５５の出力信号、回路の０ＶＧＮＤ信号と引き算され、その出力信号は、補償回路ａ７０ａ、ｂ７０ｂ、ｃ７０ｃ、ゲイン調整器ａ７１ａ、ｂ７１ｂ、ｃ７１ｃを介して駆動アンプａ５７ａ、ｂ５７ｂ、ｃ５７ｃに入力されており、スイッチ４、５、６（６８ａ〜６８ｃ）以降から駆動アンプａ５７ａ、ｂ５７ｂ、ｃ５７ｃまでで第１のサーボ制御手段７６を構成しており、その出力信号は第１の圧電素子２７ａ〜２７ｃに接続されている。駆動アンプａ５７ａ、ｂ５７ｂ、ｃ５７ｃへの入力信号に対する第１の押圧手段４７ａ〜４７ｃ変位量の間の周波数特性は、図１９に示すように２次系であり、補償回路ａ７０ａ、ｂ７０ｂ、ｃ７０ｃを調整することにより一般的なサーボ系の安定指標値である位相余裕４０度以上とゲイン余裕１５ｄＢ以上に設けている。以上の構成によれば、第１の圧電素子２７ａ〜２７ｃの印加電圧が比較的大きくても、言い換えるとローラ８ａ〜８ｃの駆動軸１に対する押圧量が大きくても第１のサーボ制御手段７６が目標値となる定電圧回路５５の出力信号、回路の０ＶＧＮＤ信号と第１の変形量測定手段３０ａ〜３０ｃからの出力信号を比較して目標値に収束するので残変位量Ｄｐを生じなくなる。
【００２３】
実施形態２で説明したのと同様の理由で、第２の圧電素子３１ａ〜３１ｃにも履歴特性がある。そのため大きなリード量を設定した場合、実施形態１の図６で説明した電圧補正手段６７による補正動作の際に時間がかかってしまう。そこで、実施形態３では、図７（ｂ）に示すように第２の押圧手段４８ａ〜４８ｃを構成する第２の押圧板３２ａ〜３２ｃの第２の変形部３２ｄ〜３２ｆに実施形態２と同様に抵抗値の変化によってその変形量を検出する歪みゲージ等の第２の変形量測定手段３４ａ〜３４ｃを設け、図９に示すようなＤ／Ａ変換器ａ６３ａ、ｂ６３ｂ、ｃ６３ｃの出力信号７４ｄ〜７４ｆを目標値とした実施形態２と同様の構成とした第２のサーボ制御手段７７を設けている。構成の説明については、実施形態２と重複するのでここでは省略する。
以上の構成では、実施形態２と同様に目標値となるＤ／Ａ変換器ａ６３ａ、ｂ６３ｂ、ｃ６３ｃの出力信号と第２の変形量測定手段３４ａ〜３４ｃからの出力信号を比較して目標値に収束するので残変位量Ｄｐを生じなくなる。
実施形態１〜３では、従動軸７ａ〜７ｃと駆動軸１の押圧調整範囲及び交差角度調整範囲は、第１の押圧手段４７ａ〜４７ｃ、第２の押圧手段４８ａ〜４８ｃに用いている第１の圧電素子２７ａ〜２７ｃと第２の圧電素子３１ａ〜３１ｃの最大伸縮量内に限定されるため例えば、大きなリード設定条件の時は対応できなくなる。そこで第４の実施形態では、大きなリード設定条件に対しても対応できる構成を説明する。
【００２４】
次に、本発明の第４実施形態について図１０（ａ）（ｂ）（ｃ）及び図１１（ａ）乃至（ｄ）（図１０の各部断面図）にて説明する。なお、第１の実施形態に係る図１等を併せて参照しつつ説明する。実施形態１の説明と重複する部分の説明は省略する。図１１（ａ）に示す第４実施形態では、第１の固定板２２は、その両側面が、移動体１３の送り方向への突出部１３ａの下部に固定されて、その凹部に従動軸７ａ〜７ｃを押圧する方向に案内部（１）２２ａ〜２２ｃを有している。更に、各案内部（１）２２ａ〜２２ｃに嵌合するよう設けられた第１の押圧板２８ａ〜２８ｃと、従動軸７ａ〜７ｃを押圧する方向に第１の固定板２２を移動させるために第１の固定板２２に設けた調整ネジ（１）２９ａ〜２９ｃと、第１の押圧板２８ａ〜２８ｃに設けた雌ネジ部によって従動軸７ａ〜７ｃを押圧する方向に位置調整可能となるように構成され、かつ、その両側面が、その凹部に従動軸７ａ〜７ｃを駆動軸１の接線方向に押圧する方向に第１の固定板２２の案内部（２）２２ｄ〜２２ｆに嵌合するよう設けられた第２の押圧板３２ａ〜３２ｃと、従動軸７ａ〜７ｃを駆動軸１外周の接線方向に押圧する方向に設けた第１の固定板２２に設けた調整ネジ（２）３３ａ〜３３ｃと、を備え、第２の押圧板３２ａ〜３２ｃの後端側面によって、従動軸７ａ〜７ｃを駆動軸１外周の接線方向に押圧する方向に位置調整可能となるよう構成している。また、第１の押圧板２８ａ〜２８ｃ、第２の押圧板３２ａ〜３２ｃの位置調整後は、図１１（ｃ）に示すように、それぞれ固定具（１）４２ａ〜４２ｃ及び固定具（２）４３ａ〜４３ｃを取り付けて送り方向に固定する構成としている。
本発明の第４実施形態では、第２の固定板２３の凹部についても、駆動軸１の軸線に対して円周方向に等角配置されて固定され、従動軸７ａ〜７ｃに設けたローラ８ａ〜８ｃを駆動軸１の外周から離間する方向に押圧するコイルスプリング等の３つの第１の弾性体３５ａ〜３５ｃ（押圧端部に球３５ｄ〜３５ｆを設けている）を備えた第３の押圧板３６ａ〜３６ｃと、駆動軸１の外周接線方向に押圧するコイルスプリング等の３つの第２の弾性体３８ａ〜３８ｃ（押圧端部に球３８ｄ〜３８ｆを設けている）を設けた第４の押圧板４０ａ〜４０ｃを設け、上記他の実施形態と同様な構成としているが、第１の弾性体３５ａ〜３５ｃ、第２の弾性体３８ａ〜３８ｃの変形ストロークが十分に大きい場合はこれらの押圧板は必要ない。
以上の構成によれば、設定する大きなリード条件に対して上記実施形態１〜３で述べた角度補正動作を行う前に手動にて、第１の押圧板２８ａ〜２８ｃと第２の押圧板３２ａ〜３２ｃを調整ネジ（１）２９ａ〜２９ｃ、調整ネジ（２）３３ａ〜３３ｃにより設定リード近傍に位置調整して第１の圧電素子２７ａ〜２７ｃと第２の圧電素子３１ａ〜３１ｃの最大伸縮量内に入るようにした後、角度補正動作を行う。
【００２５】
実施形態１〜４では、ローラ８ａ〜８ｃの駆動軸１に対する押圧以降は予圧と称する力を直接制御せず、第１の圧電素子２７ａ〜２７ｃの伸縮量を指令値通りに設定する実施形態としてきた。この場合、問題点の２で説明したようにローラ８ａ〜８ｃの駆動軸１に対する現在予圧量が定量的に確認できない。そこで、実施形態５、６、７では、ローラ８ａ〜８ｃの駆動軸１に対する予圧を制御する構成を説明する。
まず、実施形態５について、図１２の断面図と、図１３の可変押圧制御手段の回路構成図を用いて説明する。第１の出力手段６４は、可変電圧回路７８と、一方の端子を０Ｖ、他方の端子に可変電圧回路７８の出力信号が接続され外部信号によりＯＮ／ＯＦＦする切換スイッチ６８（６８ａ〜６８ｃ）と、第１の押圧板２８ａ〜２８ｃと回動支持点２４ａ〜２４ｃとローラ８ａ〜８ｃ間にあって、従動軸７ａ〜７ｃの外周部における従動軸７ａ〜７ｃの押圧方向の変形量を検出する第３の変形量測定手段４６ａ〜４６ｃと、切換スイッチ６８ａ〜６８ｃの出力信号７９ａ〜７９ｃである押圧設定信号と第３の変形量測定手段４６ａ〜４６ｃの出力信号８０ａ〜８０ｃである現在押圧量とを比較してサーボ制御する第３のサーボ制御手段８３から構成されている。この構成では、従動軸７ａ〜７ｃに設けたローラ８ａ〜８ｃの駆動軸１への予圧量を従動軸７ａ〜７ｃの押圧方向の変形量として検出している。この時、押圧は従動軸７ａ〜７ｃの弾性変形内で行われ、第１の圧電素子２７ａ〜２７ｃへの印加電圧に対する予圧量の関係は線形になることは言うまでもない。さらに、実施形態５では、可変電圧回路７８の出力を予圧設定信号としているので予圧量を手動にて自在に設定できる構成となっている。
【００２６】
又、実施形態６では、図１５の押圧サーボ制御手段（１）の回路図に示すように、実施形態５の第１の出力手段６４の構成における可変電圧回路７８と一方の端子を０Ｖ、他方の端子に可変電圧回路７８の出力信号が接続され、外部信号によりＯＮ／ＯＦＦする切換スイッチ６８の部分をＣＰＵ５８へ接続されたＤ／Ａ変換器ｄ８４として、その出力信号８５である押圧設定信号と第３の変形量測定手段４６ａ〜４６ｃの出力信号８０ａ〜８０ｃである現在押圧量とを比較してサーボ制御する第４のサーボ制御手段８６から構成している。この構成では、角度調整時の押圧開放は、Ｄ／Ａ変換器ｄ８４の出力が０Ｖとなるデジタルデータが出力される構成であり、又、実施形態１〜５で説明したＣＰＵ５８からのスイッチ操作信号の構成はない。この構成では、例えば、適正な予圧設定条件データをＲＯＭ６０に格納されるプログラム内に定数として記述しておけば、適正な予圧を瞬時に設定でき、ローラや駆動軸の磨耗による経年変化に伴う予圧の再調整作業等を行わなくてよい。
実施形態６の構成では、第１の押圧手段４７ａ〜４７ｃの第１の圧電素子２７ａ〜２７ｃへの押圧設定信号が一つしか与えられないので、例えば、従動軸７ａ〜７ｃの加工ばらつき等により押圧時の変形量にばらつきが生じたり、ブリッジ回路や第３の変形量測定手段４６ａ〜４６ｃに用いている歪みゲージ等のばらつきがあると同一の予圧量が得られない場合がある。これを回避する構成を実施形態７にて説明する。
【００２７】
実施形態７では、図１６に示すように、第１の出力手段６４は、複数の第１の圧電素子２７ａ〜２７ｃへの押圧設定信号を独立に与える複数のＤ／Ａ変換器ｄ８４ａ、ｅ８４ｂ、ｆ８４ｃと、第１の押圧板２８ａ〜２８ｃと、回動支持点２４ａ〜２４ｃとローラ８ａ〜８ｃ間にあって、従動軸７ａ〜７ｃの外周部における従動軸７ａ〜７ｃの押圧方向の変形量を検出する第３の変形量測定手段４６ａ〜４６ｃと、複数のＤ／Ａ変換器ｄ８４ａ、ｅ８４ｂ、ｆ８４ｃの出力信号８５ａ〜８５ｃである押圧設定信号と、第３の変形量測定手段４６ａ〜４６ｃの出力信号８０ａ〜８０ｃである現在押圧量とを比較してサーボ制御する第５のサーボ制御手段８７から構成されている。この構成では、例えば、従動軸７ａ〜７ｃの押圧量と変形量の関係を予めデータ取りして把握しておき、各々の異なる押圧設定信号を複数のＤ／Ａ変換器ｄ８４ａ、ｅ８４ｂ、ｆ８４ｃより出力する。
なお、実施形態１〜７では説明しなかったが、図２０の従動軸の変位拡大機構図に示すように従動軸７ａ〜７ｃは、第１の押圧手段４７ａ〜４７ｃの押圧点と回動支持点２４ａ〜２４ｃ間距離をＬ１、回動支持点２４ａ〜２４ｃとローラ８ａ〜８ｃ間距離をＬ２とした時に、Ｌ２＞Ｌ１となるような変位拡大機構を構成している。この構成によれば、第１の押圧手段４７ａ〜４７ｃに用いる第１の圧電素子２７ａ〜２７ｃの伸縮量が小さくてもローラ８ａ〜８ｃと駆動軸１とのころがり接触端では大きな押圧ストロークが得られるので駆動軸回りに配置する機構を小さく構成できることは言うまでもない。
【００２８】
【発明の効果】
以上記載のごとく請求項１の発明によれば、加工、組み付け誤差等による機械的な位置誤差のために生じる各従動軸と駆動軸とのなす交差角度のばらつきを補正できるようにしているので、各ローラ軸芯と駆動軸とのなす角度が精密に設定され、駆動軸と各従動軸のローラ間でリード誤差によるすべりを発生せず、安定した送り制御が実現でき、送り精度の向上が図れる。
また請求項２では、移動手段は、外周にローラが設けられ、移動リングの一端と対向する従動軸の一端に内周部が固着された円盤状の弾性板と、従動軸に設けられた少なくとも１つ以上の貫通穴に嵌合し、先端部がテーパ状の突き出しピンのテーパ部に接触する複数の鋼球を設けた構成としており、単純な構成でローラの移動／固定とその移動量検出が可能となり装置コストが安価となる。
また請求項３では、移動量検出手段は、ひずみを検出するひずみゲージとブリッジ回路と増幅器から構成しており、単純な構成でローラの移動／固定とその移動量検出が可能となり装置コストが安価となる。
また請求項４では、第１の出力手段を、定電圧回路と、外部信号によりＯＮ／ＯＦＦする切換スイッチと、第１の押圧板に設けた第１の変形量測定手段と、切換スイッチの出力信号と第１の変形量測定手段の出力信号とを比較してサーボ制御する第１のサーボ制御手段を設けたことにより、ローラの駆動軸外周への押圧（予圧）動作と各従動軸と駆動軸との交差角度を補正する角度補正動作を再現性よく行えるので、更に、安定した送り制御が実現でき、送り精度の向上が図れる。
また請求項５では、第２の出力手段は、Ｄ／Ａ変換器の出力信号と第２の変形量測定手段の出力信号とを比較してサーボ動作を行う第２のサーボ制御手段を設けているので、ローラの駆動軸外周への押圧（予圧）動作と各従動軸と駆動軸との交差角度を補正する角度補正動作を再現性よく行えるので、更に、安定した送り制御が実現でき、送り精度の向上が図れる。
【００２９】
また請求項６では、角度調整手段は、第１の固定板の第１の案内部に嵌合するよう設けられた第１の押圧板と、第１の固定板に設けた調整ネジと第１の押圧板に設けた雌ネジ部によって位置調整可能となるように設けられ、かつ、第１の固定板の第２の案内部に嵌合するよう設けられた第２の押圧板と、第１の固定板に設けた調整ネジと第２の押圧板によって従動軸を駆動軸外周の接線方向に押圧する方向に位置調整可能となるように設けて、大きな交差角度でも上記角度補正動作が行えるようにしているので、広いリード条件範囲において安定した送り制御が実現でき、送り構成要素としての汎用性を高くすることができる。
また請求項７では、第１の出力手段は、可変電圧回路とグランドとを外部信号によりＯＮ／ＯＦＦする切換スイッチの出力信号である押圧設定信号と第３の変形量測定手段の出力信号である現在押圧量とを比較してサーボ制御する第３のサーボ制御手段を設けているので、ローラの駆動軸に対する予圧量を従動軸の変形量に置換した信号で予圧サーボをしているので、適正な予圧条件に瞬時に設定でき、ローラや駆動軸の磨耗による経年変化に伴う予圧の再調整も容易となり、部品交換時の予圧量再現性も良好となり組立性の向上が図れる。
【００３０】
また請求項８では、第１の出力手段は、一つのＤ／Ａ変換器と、従動軸の外周部に従動軸の押圧方向の変形量を検出する第３の変形量測定手段と、Ｄ／Ａ変換器の出力信号と第３の変形量測定手段の出力信号とを比較してサーボ制御する第４のサーボ制御手段を設けて、ローラの駆動軸に対する予圧量を従動軸の変形量に置換した信号で予圧サーボをしているので、適正な予圧条件に瞬時に設定でき、ローラや駆動軸の磨耗による経年変化に伴う予圧の再調整も容易となり、部品交換時の予圧量再現性も良好となり組立性の向上が図れる。
また請求項９では、第１の出力手段は、複数のＤ／Ａ変換器の出力信号と第３の変形量測定手段の出力信号とを比較してサーボ制御する第５のサーボ制御手段を設けて、ローラの駆動軸に対する予圧量を従動軸の変形量に置換した信号で予圧サーボを行い、かつ各々の第１の押圧手段への押圧設定値を独立に与えるようにしているので、ベースに固定される案内機構の固定部である支柱の送り方向真直と駆動軸の送り方向真直に誤差を生じて組み立てが行われても、移動体が送り方向に動作した時の組立誤差による予圧変動を生じることがなく、各々のローラと駆動軸外周で発生する駆動力にもばらつきを発生しないので、長ストロークの駆動でも安定した送り動作が実現でき送り制御精度及び組立性の向上がはかれるとともに簡便な案内機構で構成できるので装置が安価となる。
また請求項１０では、従動軸は、第１の押圧手段に用いる圧電素子の伸縮量が小さくても大きな押圧ストロークが得られるので、駆動軸回りに配置する機構を小さくでき、装置の小型化が図れる。
【図面の簡単な説明】
【図１】（ａ）（ｂ）及び（ｃ）は本発明の第１の実施形態に係る摩擦駆動装置の構成を示す上面図、右側面図、及び部分破断面図である。
【図２】（ａ）（ｂ）（ｃ）及び（ｄ）は本発明の第１の実施形態のＡ−Ａ’断面図、Ｂ−Ｂ’断面図、Ｃ−Ｃ’断面図、及び弾性体部の構成説明図である。
【図３】（ａ）及び（ｂ）は図２の各部の断面図である。
【図４】（ａ）及び（ｂ）は本発明の押圧手段の詳細図である。
【図５】本発明の一実施形態に係る角度調整手段のブロック図である。
【図６】本発明の角度調整手段の動作を説明するフローチャートである。
【図７】（ａ）及び（ｂ）は本発明の第２、第３実施形態に係る押圧手段の詳細図である。
【図８】本発明の第１のサーボ制御手段のブロック図である。
【図９】本発明の第２のサーボ制御手段のブロック図である。
【図１０】（ａ）（ｂ）及び（ｃ）は本発明の第２の実施形態に係る摩擦駆動装置の構成を示す上面図、右側面図、及び部分断面図である。
【図１１】（ａ）（ｂ）（ｃ）及び（ｄ）は本発明の第２の実施形態の各部の断面図である。
【図１２】本発明の第５の実施形態の構成を示す断面図である。
【図１３】本発明の実施形態に係る可変押圧制御手段のブロック図である。
【図１４】本発明の圧電素子の印加電圧と変位量特性との関係を示す図である。
【図１５】本発明の第６の実施形態に係る第１の押圧サーボ制御手段の構成図である。
【図１６】本発明の第７の実施形態に係る第２の押圧サーボ制御手段の構成図である。
【図１７】本発明における交差角度とリードの関係を示す図である。
【図１８】本発明における従動軸の交差図である。
【図１９】本発明において駆動アンプに入力に対する変位量の伝達関数の説明図である。
【図２０】本発明における従動軸の変位拡大機構図である。
【符号の説明】
１ 駆動軸、７ 従動軸、８ ローラ、９ａ ころがり軸受（２）、１３ 移動体、１４ ころがり軸受、１５ａ 受光部、１５ｂ スケール、１６ 位置検出手段、１８ ターンテーブル、１９ エアスピンドル、２０ モータ、２１ 光学式ロータリーエンコーダ、２２ 第１の固定板、２３ 第２の固定板、８９支柱、９０ ベース[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a friction drive device, and more particularly to a friction drive device that advances and retracts a moving body having a driven shaft fixed by rotating a drive shaft.
[0002]
[Prior art]
With the recent increase in the density of optical disks, in order to realize higher resolution exposure, an exposure apparatus using an electron beam or the like instead of a conventional laser beam has been used as a light source for a mastering apparatus. Accompanying the shift to an exposure apparatus that realizes high-resolution exposure, it is necessary to cope with a vacuum environment and feed with higher accuracy. Conventionally, as this feed mechanism, a slide table device for exposure of an optical disc master is used, and an air slide type in which a table is provided so as to be movable back and forth through a hydrostatic bearing is often used. As a table driving means, a voice coil type linear motor is generally used, and a closed loop control system using an interference laser length measuring device or a linear scale as a position detector is adopted. In addition, since a semiconductor inspection apparatus or the like that requires a stationary state requires rigidity in the feed direction, a ball screw or the like is used to drive the table.
As the friction drive mechanism of the slide table device, there are a twist roller method in which the intersecting angle between the drive shaft and the driven shaft is an acute angle and a capstan method in which the angle is a right angle. The twist roller method is expected as a next-generation feed mechanism because it can realize a small lead that cannot be obtained by other mechanisms by minimizing the crossing angle between the drive shaft and the driven shaft, and high positioning resolution can be expected. Documents, patents, etc. are published.
[0003]
As a conventional technique disclosed as a mechanical mechanism, Japanese Patent Application Laid-Open No. 8-184360 discloses high disturbance resistance, uniform speed, stable feed, and improvement in static performance when the drive source is stopped. A high-rigidity advance / retreat apparatus is disclosed. This includes a shaft body and an advancing / retreating part that penetrates the shaft body so as to be relatively rotatable and reciprocating. The advancing and retracting parts are provided with a plurality of barrel-shaped rollers arranged in the body in the circumferential direction. These rollers are rotatably supported between the advancing / retreating part main body and the preloading plate via balls on both end faces. At least one of the advancing / retreating part main body and the roller end surface, and at least one of the preloading plate and the roller end surface support the ball by a conical ball support concave portion into which the ball is rotatably fitted. In addition, an elastic body is provided that urges the preload plate toward the roller and urges the preload plate in the circumferential direction.
Further, the invention according to Japanese Patent Application Laid-Open No. 11-195247 can perform stable feeding without causing unevenness of the speed, is resistant to disturbances, and can improve resolution, thereby enabling high-density writing. A slide table device for an optical disc mastering device is disclosed. According to this, a frictional advance / retreat drive device is provided that statically supports a slide body serving as a table with a static pressure linear bearing on a base, and drives the slide body slidably with respect to the base. The frictional advance / retreat drive device includes a main shaft that is rotationally driven and a plurality of rollers that are provided around the main shaft and that contact each other with an inclination angle. A preloading means for applying a preload to the main shaft to the roller is provided.
[0004]
Japanese Patent Application Laid-Open No. 11-195248 discloses a frictional advance / retreat drive device including a main shaft and a roller that is obliquely rolling with the main shaft. There is disclosed a friction advance / retreat drive apparatus that can reduce the number and position accurately. This is a friction advance / retreat drive device having a main shaft, a roller that is in rolling contact with the outer periphery of the main shaft and inclined with an inclination angle with respect to the main shaft, and a slide body that moves together with the roller that moves due to the rotation of the main shaft. The rotary drive source for rotating the main shaft and a speed reducer for reducing the rotation of the rotary drive source by transmitting the rotation from the drive side shaft to the friction wheel and transmitting the rotation to the main shaft are provided. According to the friction advancing / retreating drive device having this configuration, by rotating the main shaft, each roller rotates with a lead angle by an inclination angle with respect to the main shaft, and the sliding body is pivoted by the frictional force of the contact portion. Move in the direction. In this case, since the rotation of the rotation drive source is decelerated and transmitted to the main shaft, the influence of the rotation unevenness of the rotation drive source on the positioning accuracy of the slide body is reduced. In addition, transmission of rotation of the rotational drive source and deceleration thereof are performed through frictional contact between the drive side shaft and the friction wheel, so that backlash or the like does not occur and precise positioning can be performed by this.
In the literature: "Development of ultra-precision positioning system using twist roller friction drive device, author Mizumoto et al., Proceedings of Autumn Meeting of Precision Engineering Society of 1995", a table guided by aerostatic bearings A drive shaft supported by an aerostatic bearing, a driven shaft provided at a slight crossing angle with the drive axis, and a roller rotatably supported around the driven shaft by a plurality of ball bearings. It is disclosed that a positioning resolution of 2 nm is realized with a 70 μm lead.
[0005]
[Problems to be solved by the invention]
However, in the invention described in Japanese Patent Laid-Open No. 8-184360, the conical surface formed on the fixed plate and the opposing plate, which are arranged at an equal angle (120 degrees) with respect to the drive shaft center and support the roller end surface, respectively. Due to the mechanical position error of the ball support recess, the angle formed by each roller shaft core and the drive shaft varies. When a large angle is formed between the roller shaft core and the drive shaft, that is, when the lead L is relatively large (for example, several mm), there is no problem, but the angle formed between the roller shaft core and the drive shaft (lead L ), For example, when setting to several hundred μm, if there is a variation in the angle between each roller shaft core and the drive shaft, a slip due to a lead error occurs between the rollers of the drive shaft and the driven shaft, Since this becomes a disturbance of closed loop control, it is not preferable in terms of control. If this is applied to optical disk master exposure, etc., there arises a problem that the track pitch accuracy is deteriorated and the exposure quality is adversely affected.
Furthermore, according to the invention according to this publication, the preloading plate is biased toward the roller side, and an elastic body that biases the roller in the circumferential direction is provided. By connecting the hole part with the screw part provided in the component body and the hole part provided in the preload plate, by providing an elastic body in the communication hole part and tightening the thread screw of the screw part provided in the advancing and retracting part body The compressive deformation force of the elastic body is used. In this configuration, since the current preload amount for the roller shaft body cannot be quantitatively confirmed, trial and error is necessary to obtain an appropriate preload amount, and the preload associated with aging due to wear of the roller and shaft body is required. Re-adjustment becomes difficult and there is no reproducibility of preload when replacing parts, resulting in poor assembly.
[0006]
Further, in Japanese Patent Application Laid-Open No. 11-195247, when assembled in a state where an error occurs between the straightness of the static pressure linear motion bearing fixing portion fixed to the base and the straightness of the frictional advance / retreat drive device main shaft, When the body moves in the feed direction, the straightness error is absorbed between the roller and the spindle with the lowest rigidity just by applying preload and fixing, so the amount of preload on the spindle along with the moving position It will change. That is, the driving force in the driving shaft direction acting between the driving shaft and one roller is F = μN, where μ is the dynamic friction coefficient between the outer periphery of the driving shaft and the roller, and N is the preload. Therefore, the driving force generated on the outer periphery of each roller and the drive shaft also varies, and further, the driving force also varies. Therefore, driving is performed in synergy with the variation of the angle between each roller shaft core and the drive shaft. Since slip occurs between the shaft and driven shaft rollers, and this causes disturbance in closed loop control, there is a problem that, when applied to optical disk master exposure or the like, the track pitch accuracy deteriorates and the exposure quality is adversely affected.
Further, according to this publication, the slide body is statically supported by the hydrostatic linear bearing on the base, and in the above document, the table guided by the air hydrostatic bearing is used as both ends of the air hydrostatic bearing. However, there is a problem that such a hydrostatic bearing is very expensive and the cost of the apparatus becomes high.
SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a friction drive device that can realize high-precision feeding without causing the above-described problems, particularly a feed stage for an optical disc master exposure apparatus.
[0007]
[Means for Solving the Problems]
  In order to solve such a problem, the present invention provides a fixed base, a drive shaft rotatably supported on the base side, and a circular with a predetermined inclination angle at an outer diameter position of the drive shaft. A plurality of driven shafts arranged equiangularly in the circumferential direction, a roller that is rotatably supported by the plurality of driven shafts and is in rolling contact with the outer periphery of the drive shaft, and a drive shaft that rotates along with the rotation of the drive shaft. A friction drive apparatus comprising: a moving body that moves in the axial direction and supports the driven shaft; and a position detection means that detects a feed position of the moving body, wherein the friction drive device includes at least one of the plurality of driven shafts. One driven shaft supports the roller so as not to move in the axial direction, and the other driven shaft includes moving means for supporting the roller so as to be movable in the axial direction, and a moving amount detecting means for detecting the moving amount. , Each driven shaft is rotatably supported And a first elastic body that presses the other end of the driven shaft away from the outer periphery of the drive shaft, and a tangential direction of the outer periphery of the drive shaft. A second elastic body, fixed to the moving body portion corresponding to the driven shaft end opposite to the roller across the rotation support point, and in a direction perpendicular to the axis of the drive shaft and the first A first pressing means that presses the driven shaft in a direction that cancels out the moment force around the rotation support point caused by the pressing force of the first elastic body, a tangential direction of the outer periphery of the drive shaft, and the second elastic body A second pressing unit that presses the driven shaft in a direction that cancels out the moment force around the rotation support point caused by the pressing force; a control unit that controls each of the constituent elements; The pressing means 1 is pressed / released, and the roller Based on the first output means that moves / fixes in the axial direction of the other driven shaft, the origin detection signal per rotation of the drive shaft, and the output signal of the roller movement amount detection means, the other driven shaft Angle error calculating means for calculating an inclination angle error of the at least one driven shaft with respect to an axis, and the angle errorCalculationAngle adjusting means having second output means for applying a correction signal obtained by increasing or decreasing an output signal corresponding to the angle error calculated by the means to the second pressing means. And
  The present invention relates to a friction drive device used in a feed stage for an optical disc master exposure apparatus for supporting and rotating the optical disc master and moving it in the radial direction when exposing the optical disc master, and provides high-precision feeding. It can be realized.
  In this invention, one end of a plurality of driven shafts is supported on the outer periphery of the drive shaft by a spherical bearing and the other end is free supported by an elastic body, and the driven shaft on the opposite side of the roller is sandwiched by the rotation support point of the spherical bearing. The other end of the first presser is pressed in the separating direction by the first pressing unit, and the second piezoelectric element is pressed in the tangential direction of the drive shaft. Further, the first output unit controlled by the control unit and the fixed driven shaft An angle error calculating means for calculating an inclination angle error and an angle adjusting means are provided, and the variation in the crossing angle between each driven shaft and the drive shaft that occurs due to a mechanical position error due to processing, assembly error, etc. It can be corrected.
  According to this invention, it is possible to correct the variation in the crossing angle between each driven shaft and the drive shaft caused by a mechanical position error due to processing, assembly error, etc. Is precisely set, slippage due to a lead error does not occur between the drive shaft and each driven shaft roller, stable feed control can be realized, and feed accuracy can be improved.
[0008]
A second aspect of the present invention is the first aspect of the present invention, wherein the moving means is disposed on the outer periphery of the other driven shaft and includes the roller via a bearing on the outer periphery, and inner peripheral surfaces of both axial ends of the roller. And a moving ring forming a sliding bearing between the outer peripheral surface of the other driven shaft and a disc-shaped elastic member having an outer peripheral portion fixed to the moving ring and an inner peripheral portion fixed to the other driven shaft. A plate, a plurality of steel balls fitted in at least one through hole provided in a direction orthogonal to the axis of the other driven shaft, and coaxially in the axial direction from one end surface of the other driven shaft A hole portion that is provided and communicates with the through-hole, and a protruding pin that is supported in the hole portion so as to be movable in the axial direction and that contacts the plurality of steel balls at a tapered tip portion. And
According to this invention, the moving means includes a disc-shaped elastic plate having a roller provided on the outer periphery and an inner peripheral portion fixed to one end of the driven shaft facing the one end of the moving ring, and at least provided on the driven shaft. It is configured to have a plurality of steel balls that fit into one or more through-holes and the tip part contacts the taper part of the taper-shaped protruding pin, and moves / fixes the roller with a simple structure and detects its movement amount And the cost of the apparatus is reduced.
In Claim 3, In Claim 1 or 2, the said movement amount detection means is a strain gauge which detects the distortion of the radial direction between the inner and outer periphery of the said disk shaped elastic board, and the bridge circuit which detects a resistance value change. And an amplifier for amplifying the signal of the bridge circuit.
According to this invention, the moving amount detecting means is composed of a strain gauge for detecting strain, a bridge circuit, and an amplifier, and it is possible to move / fix the roller and detect the moving amount with a simple configuration, and the apparatus cost is low. It becomes.
[0009]
According to a fourth aspect of the present invention, the first output means includes a constant voltage circuit for generating a constant voltage, one terminal at 0 V, and the other terminal connected to the output signal of the constant voltage circuit, and is turned on / off by an external signal. A changeover switch, a first deformation amount measuring means provided in a first deformation portion of the first pressing plate, a press expansion / contraction setting signal which is an output signal of the changeover switch, and an output of the first deformation amount measuring means. And a first servo control means for performing servo control by comparing a current pressing expansion / contraction amount as a signal.
According to this invention, the first output means includes a constant voltage circuit, a changeover switch that is turned on / off by an external signal, the first deformation amount measuring means provided on the first pressing plate, and the output of the changeover switch. By providing the first servo control means for servo-control by comparing the signal and the output signal of the first deformation amount measuring means, the pressing (preload) operation of the roller to the outer periphery of the drive shaft and the driving of each driven shaft Since the angle correction operation for correcting the crossing angle with the axis can be performed with high reproducibility, further stable feed control can be realized and feed accuracy can be improved.
According to a fifth aspect of the present invention, the second output unit includes a D / A converter that converts a digital signal from the CPU into an analog signal, and a second deforming unit provided in the second pressing unit. The deformation amount measuring means, a press expansion / contraction setting signal that is an output signal of the D / A converter, and a current pressing expansion / contraction amount that is an output signal of the second deformation amount measuring means are compared to perform a servo operation. 2 servo control means.
According to this invention, the second output means includes the second servo control means for performing a servo operation by comparing the output signal of the D / A converter and the output signal of the second deformation amount measuring means. As a result, the roller can be pressed (preload) to the outer periphery of the drive shaft and the angle correction operation to correct the crossing angle between each driven shaft and the drive shaft can be performed with high reproducibility. Accuracy can be improved.
[0010]
  According to a sixth aspect of the present invention, the angle adjusting means includes theMoving bodyA first fixing plate fixed to the first fixing plate, a first pressing plate provided so that both side surfaces are fitted to a first guide portion provided on the first fixing plate, fixed to the moving body and the A first adjusting screw provided on the first fixing plate and a female screw portion provided on the first pressing plate for adjusting the position by pressing the driven shaft, and the driven shaft supported by the movable body And a second pressing plate provided so as to be fitted to a second guide portion provided on the first fixing plate and pressing the driven shaft on the drive side. The driven shaft is tangent to the outer periphery of the drive shaft by a second adjustment screw provided on the first fixing plate for pressing in the tangential direction of the outer periphery of the shaft and a rear end side surface of the second pressing plate. It is configured so that the position can be adjusted by pressing in the direction.
  According to this invention, the angle adjusting means includes the first pressing plate provided to fit in the first guide portion of the first fixing plate, the adjusting screw provided on the first fixing plate, and the first A second pressing plate provided so as to be position-adjustable by a female screw portion provided on the pressing plate, and fitted to the second guide portion of the first fixing plate; The adjustment screw provided on the fixed plate and the second pressing plate are provided so that the position of the driven shaft can be adjusted in the direction tangential to the outer periphery of the drive shaft so that the angle correction operation can be performed even at a large crossing angle. Therefore, stable feed control can be realized in a wide range of lead conditions, and versatility as a feed component can be enhanced.
  According to a seventh aspect of the present invention, the first output means includes a variable voltage circuit configured such that the voltage can be changed, one terminal is set to 0 V, and the output signal of the variable voltage circuit is connected to the other terminal. ON / OFF changeover switch, third deformation amount measuring means for detecting the deformation amount in the pressing direction of the driven shaft between the first pressing plate, the rotation support point and the roller, and the changeover switch And a third servo control means for servo-controlling the press setting signal, which is an output signal of the second, and the current press amount, which is an output signal of the third deformation amount measuring means,.
  According to this invention, the first output means is a pressing setting signal which is an output signal of a changeover switch for turning on / off the variable voltage circuit and the ground by an external signal, and an output signal of the third deformation amount measuring means. Since there is a third servo control means that performs servo control by comparing the current pressing amount, preload servo is performed with a signal that replaces the preload amount for the drive shaft of the roller with the deformation amount of the driven shaft. The preload conditions can be set instantly, the preload can be readjusted with the passage of time due to wear of the rollers and the drive shaft, and the reproducibility of the preload at the time of parts replacement can be improved and the assemblability can be improved.
[0011]
  According to an eighth aspect of the present invention, the first output means includes one D / A converter that converts a digital signal from the CPU into an analog signal, the third deformation amount measuring means, and the one D / A conversion. And a fourth servo control means for servo-controlling the press setting signal, which is an output signal of the device, and the current press quantity, which is the output signal of the third deformation amount measuring means, .
  According to this invention, the first output means includes one D / A converter, the third deformation amount measuring means for detecting the deformation amount of the driven shaft in the pressing direction, and the D / A converter. A fourth servo control means for servo-controlling the output signal of the A converter and the output signal of the third deformation amount measuring means is provided, and the preload amount for the driving shaft of the roller is replaced with the deformation amount of the driven shaft. Since the preload servo is performed with the selected signal, the appropriate preload condition can be set instantaneously, the preload can be readjusted due to aging due to wear of the roller and drive shaft, and the reproducibility of the preload when replacing parts is also good. As a result, the assembly can be improved.
  According to a ninth aspect of the present invention, the first output means includes a plurality of D / A converters that convert digital signals from the CPU into analog signals in order to independently provide pressing setting signals to the plurality of piezoelectric elements; And a servo control by comparing a pressing setting signal which is an output signal of the plurality of D / A converters with a current pressing amount which is an output signal of the third deformation amount measuring means. Servo control means.
  According to this invention, the first output means includes the fifth servo control means for performing servo control by comparing the output signals of the plurality of D / A converters with the output signals of the third deformation amount measuring means. Thus, the preload servo is performed with a signal obtained by replacing the preload amount with respect to the driving shaft of the roller with the deformation amount of the driven shaft, and the pressure setting value for each first pressing means is independently given. Even if assembly is performed with an error in the feed direction straightness of the column, which is the fixed part of the fixed guide mechanism, and the drive shaft feed direction straightness, the preload fluctuation due to the assembly error when the moving body operates in the feed direction Since there is no variation in the driving force generated on the outer periphery of each roller and the drive shaft, stable feed operation can be realized even with long stroke drive, and feed control accuracy and assemblability can be improved and simple. guide Can be constructed in a configuration device is inexpensive.
  According to a tenth aspect of the present invention, the driven shaft has a condition of L2> L1 when the distance between the pressing point of the first pressing means and the rotation support point is L1, and the distance between the rotation support point and the roller is L2. A third deformation amount measuring means displacement enlarging mechanism that satisfies the above is formed.
  According to this invention, since the driven shaft can obtain a large pressing stroke even if the expansion and contraction amount of the piezoelectric element used for the first pressing means is small, the mechanism disposed around the drive shaft can be reduced, and the apparatus can be downsized. I can plan.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the components, types, combinations, shapes, relative arrangements, and the like described in this embodiment are merely illustrative examples and not intended to limit the scope of the present invention only unless otherwise specified. .
FIG. 1 is a control system configuration diagram of a friction drive apparatus according to a first embodiment of the present invention. 1A is a top view of the friction drive device, FIG. 1B is a right side view thereof, and FIG. 1C is a partial cross-sectional view thereof. This friction drive device is used, for example, in a feeding device used in an optical disc master exposure apparatus.
On a base 90 provided on an anti-vibration mechanism (not shown), for example, a pneumatic servo mounter, columns 89 (89a, 89b) that are spaced apart in a direction orthogonal to the feed direction and have a base end fixed to the base 90 are provided. The movable body 13 can be moved in the feed direction via a rolling bearing 14 (14a, 14b, guide mechanism) in which, for example, a spherical body, a cylindrical roller, and the like are arranged in the feed direction. It is supported by.
[0013]
A turntable 18 that supports an optical disc master as a workpiece is fixed to the moving body 13, and an air spindle 19 that floats statically in the radial and thrust directions by compressed air supplied from outside (not shown) The output of the air spindle 19 is transmitted to the air spindle 19 via the rotary drive motor 20, and the output is A-phase and B-phase pulses that are equally divided into several rounds (360 degrees) and Z generated once per round. An optical rotary encoder (1) 21 composed of a phase pulse is fixed, and is configured to be rotatable by an energization signal to an external rotation drive motor 20 (not shown).
Further, at the lower part of the left end portion when viewed from the feed direction of the moving body 13, for example, the position in the feed direction of an optical linear encoder or the like composed of A-phase and B-phase pulses providing a predetermined resolution in the feed direction Position detecting means 16 comprising a light receiving portion 15a for measuring the pressure and a scale 15b is provided. The scale 15b is fixed to the moving body 13 via the mounting plate (1) 15c, and the light receiving portion 15a is fixed to the base 90 side via the mounting plate (2) 17. In FIG. 1, the scale 15 b is fixed to the moving body 13 and the light receiving unit 15 a is fixed to the base 90. However, the light receiving unit 15 a may be fixed to the moving body 13 and the scale 15 b may be fixed to the base 90. Absent.
Further, the first fixing plate 22 and the second fixing plate 23 provided with holes 22a and 23a for supporting the drive shaft 1 extending in the lateral direction are provided below the protruding portion 13a protruding from the moving body 13 in the feeding direction. Each upper end is fixedly supported. Furthermore, three driven shafts 7a to 7c provided concentrically via roller bearings (2) 9a to 9c facing roller bearings (2) 9a to 9c, for example, which are in rolling contact with the outer periphery of the drive shaft 1, are provided on the drive shaft 1. It is equiangularly arranged in the circumferential direction with respect to the axis line.
[0014]
  2A shows the A-A ′ cross section of FIG. 1, FIG. 2B shows the B-B ′ cross section, and FIG. 2C shows the C-C ′ cross section. FIG. 2D is a detailed view of the elastic body portion. The right end portions of the driven shafts 7a to 7c are respectively recessed portions provided in the second fixing plate 23 at a predetermined pitch in the circumferential direction, as shown in the cross-sectional view of FIG. 23A, 23B, and 23C are arranged so as to be equiangular in the circumferential direction with respect to the axis of the drive shaft 1, respectively.supportHas been. Further, the balls 35d to 35f that press the rollers 8a to 8c rotatably supported on the outer circumferences of the driven shafts 7a to 7c in the direction (separation direction) away from the outer circumference of the drive shaft 1 are coil springs or the like. 3rd press plates 36a-36c provided with the structure pressed by three 1st elastic bodies 35a-35c (it arranges at a press end) (refer to Drawing 2 (d)), and each driven shaft 7a- 4th provided with the structure which presses the ball | bowl 38d-38f which presses 7c to the outer peripheral tangent direction of the drive shaft 1 by three 2nd elastic bodies 38a-38c (arranged in a press end part), such as a coil spring. Press plates 40a to 40c are provided. In this manner, the right end portions of the driven shafts 7a to 7c are configured to be freely supported by the elastically biased balls. In the embodiment of the present invention, the first pressing members 36a to 36c and the fourth pressing plates 40a to 40c separated from the second fixing plate 23 are respectively provided with the first elastic bodies 35a to 35c and the second pressing members 35a to 35c. Although the elastic bodies 38 a to 38 c are provided, the elastic bodies may be provided directly on the second fixing plate 23.
[0015]
Further, on the right side surface of the first fixing plate 22, as shown in the partial cross-sectional view of FIG. 1C and the cross-sectional views of FIGS. 2A and 2C, the left end of the driven shafts 7 a to 7 c. Bearings 26a to 26c such as spherical bearings, which are fitted to the outer periphery of the part and the inner periphery thereof, are fixed at an equal angle in the circumferential direction with respect to the axis of the drive shaft 1, and the driven shafts 7a to 7c are The bearings 26a to 26c are configured to be rotatable within a plane including the rotation support points 24a to 24c. Further, in the recesses 22A, 22B, and 22C of the first fixing plate 22, on the side opposite to the rollers 8a to 8c with the rotation support points 24a to 24c interposed therebetween, FIG. 2 (a) and FIG. 4 (a). The first piezoelectric elements 27a to 27c as shown in FIG. In other words, the first pressing means 47 a to 47 c and the second pressing means 48 a to 48 c are equiangularly arranged in the circumferential direction with respect to the axis of the drive shaft 1 and fixed.
That is, the first pressing means 47a to 47c cancel the moment force around the rotation support points 24a to 24c by the pressing force of the first elastic bodies 35a to 35c in the direction perpendicular to the axis of the drive shaft 1. The first piezoelectric elements 27a to 27c for pressing the driven shafts 7a to 7c are fixed in the expansion / contraction direction, and the first deforming portions 28d to 28f are provided at the fixed ends on the side for pressing the driven shafts 7a to 7c. It has. The second pressing means 48a to 48c are driven shafts in a direction that cancels out the moment forces around the rotation support points 24a to 24c due to the pressing force of the second elastic bodies 38a to 38c in the tangential direction of the outer periphery of the drive shaft 1. The second piezoelectric elements 31a to 31c as shown in FIG. 4 (b) that press the 7a to 7c are fixed in the expansion / contraction direction, and the second deforming portions 32d to 32d are fixed to the fixed end on the side pressing the driven shafts 7a to 7c. 32f is provided.
[0016]
  Further, the right end portion of the drive shaft 1 is a first stepped portion 1a, the outer periphery of which is fixed to the base 90 and is provided in the left cylindrical hole portion 10a of the housing 10 provided with a stepped through hole in the upper portion. The outer ring is concentrically fitted to the inner peripheral portion of an opposing rolling bearing 32 such as an angular bearing, and the inner peripheral portion of the threaded point bearing 32 provided on the drive shaft 1 serves as the bearing stopper 3. Is fixed. Further, the outer periphery of the second stepped portion 1b of the drive shaft 1 is concentrically fixed to the right cylindrical hole of the housing 10, and the output is generally divided into several thousand or the like in the A phase and B phase. A drive shaft of a feed drive motor 5 to which a rotary encoder (2) 6 composed of a pulse and a Z-phase pulse generated once per round is fixed is connected by an Oldham type coupling 4. Furthermore, the outer periphery of the stepped portion 1c located at the left end portion of the drive shaft 1 is fixed to the base 90 and provided with a through hole in the upper portion, and is concentric with the through hole, for example, a rolling bearing such as a deep groove ball bearing. (4) The outer ring of 12 is fitted to the inner ring of the rolling bearing (4) 12 fixed so as to be movable in the axial direction.
  With the above configuration, appropriate energization voltages are applied to the second piezoelectric elements 31a to 31c and the first piezoelectric elements 27a to 27c from lead terminals of the first piezoelectric elements 27a to 27c and the second piezoelectric elements 31a to 31c (not shown). When applied in the order of 27c, the outer periphery of the rollers 8a to 8c and the outer periphery of the drive shaft 1 with the axis of the drive shaft 1 and the axis of the driven shafts 7a to 7c intersecting at an angle θ as shown by the dotted line in FIG. Rolling contact. In this state, if current is supplied from the terminal of the feed drive motor 5 (not shown), the contact points between the outer circumferences of the rollers 8a to 8c and the outer circumference of the drive shaft 1 move spirally, and the movable body 13 can move in the feed direction. . At this time, the driven shafts 7a to 7c themselves do not rotate, and the outer ring of the rolling bearings (2) 9a to 9c rotates. Further, the movement amount L lead amount by which the drive shaft 1 moves the movable body 13 per one rotation is as follows.
  L = π · D · tan θ    -------- (1)
  θ = tan -1 {L / π · D}------- (2)
For example, the relationship between the crossing angle and the lead amount L under the condition of D = 30 mm is linear as shown in the log-log graph of FIG.
[0017]
Further, as shown in FIG. 3, one driven shaft 7a is provided with a roller 8a fixed so as not to move in the axial direction of the driven shaft 7a and rotatably supported, and the other driven shafts 7b and 7c have A moving ring 91 (91b, 91c) supporting a sliding bearing 98 (98b, 98c) between the inner peripheral surface of both axial ends and the outer peripheral surface of the driven shafts 7b, 7c is concentric with the driven shafts 7b, 7c. Is provided. Further, a disc-shaped elastic plate 92 (92b, 92c) having an outer peripheral portion fixed to one end of the moving ring 91 in the axial direction and an inner peripheral portion fixed to one end of the driven shafts 7b, 7c facing the one end. ) Is provided to constitute the moving means 97 (97b, 97c), and the rollers 8b, 8c can move in the axial direction of the driven shafts 7b, 7c.
Further, each driven shaft 7b, 7c is provided with a through hole 99 in a direction orthogonal to the axis, and concentric holes (shaft holes) 7b-1, 7c-1 formed from the right end portion in the figure. Are provided so as to communicate with the through holes 99, respectively. In this hole portion, the inner wall and outer periphery of the hole portion are substantially fitted (freely fitted), and an O-ring or the like (not shown) is provided on the outer periphery, and a protruding pin 94 (94b, 94c) having a tapered tip portion is provided in the axial direction. Support to move forward and backward. For example, the protruding pin 94 is elastically biased outward in the axial direction by the compression coil spring 96 (96b, 96c). Further, a plurality of steel balls (ball bearings) 95 that are fitted into the through holes 99 and are in contact with the tapered portion located at the inner end portion of the protruding pin 94 are provided. In this configuration, when compressed air or the like is supplied into the hole from an air supply port that is an opening of the hole formed in the axial direction from the right end of the driven shafts 7b and 7c, the protruding pin 94 is moved to the driven shaft 7b, The steel ball 95 moved to the left of the axis 7c and in contact with the tapered portion moves in a direction perpendicular to the axis of the driven shafts 7b and 7c, and presses the inner peripheral surface of the moving ring 91 surrounding the driven shaft. Then, the moving ring 91 and the driven shafts 7b and 7c are fixed.
Further, strain gauges 93 (93b, 93c) for detecting the radial strain between the inner and outer peripheries of the disk-shaped elastic plate 92 are provided, and lead terminals (not shown) of the respective strain gauges are shown in FIG. The bridge circuit 101 (101b, 101c) is connected to each other, and the output signal of the bridge circuit 101 is connected to the amplifier 102 (102b, 102c), and the movement amount of the rollers 8b, 8c is set to each elastic plate 92 (92b, 92c). The movement amount detecting means 100 is configured as a whole.
[0018]
Next, a control block diagram for adjusting the angles of the driven shafts 7a to 7c will be described with reference to FIG. A CPU 58 to which a signal line of a Z-phase pulse signal 49 that is generated once every rotation of the rotary encoder 26 as an interrupt signal is connected is connected to a ROM 60 for writing the operation program and a RAM 61 for storing data. An A / D converter 103 (103b, 103c) that converts an analog output signal of the movement amount detection means 100 into a digital signal using the rising edge of the pulse signal 49 as a trigger signal is connected. The output signals are connected to drive amplifiers d57d, e57e, f57f connected to terminals (not shown) of the second piezoelectric elements 31a to 31c, and D / A converters a63a, b63b for converting digital data into analog signals. c63c is connected. Here, the D / A converters a63a, b63b, c63c and the drive amplifiers d57d, e57e, f57f constitute the second output means 50. Further, the output signals of the drive amplifiers a57a, b57b, c57c connected to terminals (not shown) of the first piezoelectric elements 27a to 27c and the output signals of the constant voltage circuit 55 (55a, 55b) for outputting a fixed constant voltage. Are connected as input signals of the drive amplifiers a57a, b57b, c57c through switches 1, 2, 3 (56a to 56c) that can be turned on / off by an external signal. 3 (56a to 56c) is connected to the CPU 58, and its output signal is connected to the solenoid valve 104 (104b, 104c), and a constant voltage circuit 55 (55a) that outputs a fixed constant voltage at the input. , 55b) are connected to drive signals of switches 4, 5 (56d, 56e) that can be turned on / off by an external signal. Further, a data input unit 59 for inputting the lead amount data L and its setting allowable error data ε is connected, and the angle adjusting means 51 is configured as a whole.
[0019]
The operation of the above circuit configuration will be described with reference to the operation flowchart of FIG. After reading in advance the read amount data L and its set allowable error data ε (S1), after waiting for a command signal 88a from the host computer of the entire apparatus (not shown) (S2), the command signal 88a from the host computer is When turned on, the angle calculation means 65 calculates the intersection angle θ based on the above equation (2) (S3), and then the drive signals of the switches 4, 56d, 5 and 56e are turned on and electromagnetic The valve 104 (104b, 104c) is operated, compressed air is supplied from the air supply port as the right end opening of each of the holes 7b-1, 7c-1 of the driven shafts 7b, 7c, and the protruding pin 94 moves. The moving ring 91 and the driven shafts 7b and 7c are fixed, the drive signals of the switches 1, 2, and 3 (56a to 56c) are turned off, and the signals to the first piezoelectric elements 27a to 27c are turned off. Then, the pressing means (1) 47a to 47c are opened (S6). Subsequently, digital data corresponding to the intersection angle θ calculated by the angle calculating means 65 is sent to the D / A converter 63 (S7), and calculated to the piezoelectric element (2) 31 via the drive amplifier 57. The displacement voltage corresponding to the crossing angle θ is applied, the pressing means (2) 48 presses the driven shaft 7 in the tangential direction of the outer periphery of the drive shaft 1, and then the drive signal to the switch (1) 56a is turned on. The output signal of the constant voltage circuit 55 set to an appropriate voltage is supplied to the piezoelectric element (1) 27a through the drive amplifier 57, and the pressing means (1) 47 presses the driven shaft 7 (S8). Thereafter, the drive signals of the switches 4, 5 (56d, 56e) are turned off (S9), the moving ring 91 and the driven shafts 7b, 7c are opened, and in this state, the feed drive motor 5 starts to rotate (S10). The movement amount Xb of the roller 8b is taken in by the A / D converter 103b using the rising edge of the Z-phase pulse signal 49 as a trigger signal (S11). Here, the driven shaft 7b has a set lead amount with respect to the set lead amount of the driven shaft 7a. When the actual read amount is large, Xi> 0, and when small, Xi <0. Thereafter, the relative lead amount calculating means 66 for calculating the relative lead amount calculates the relative lead amount Lb, calculates the relative angle error Δθb, and the movement amount Xb of the roller 8b is equal to or less than the set allowable error data ε. If the difference data Δθb is larger than 0, Δθb is subtracted from the set angle data, and if Δθb is smaller than 0, the angle data θb is stored in the RAM 61. The voltage correction unit 67 for adding Δθb to the voltage correction unit 67 sequentially repeats the process until ε ≧ Xi (S12).
[0020]
Step S5 in the above flow is a subroutine (SUB). When the above operations are performed in the order of b and c and all are completed, the drive signals of the switches 1, 2, and 3 (56a to 56c) are turned off. Thus, the signals to the piezoelectric elements (1) 27a to 27c are turned off, the first pressing means 47a to 47c are opened, the drive signals of the switches 4, 5 (56d, 56e) are turned on, and the electromagnetic valves 104 (104b, 104c) is operated, compressed air or the like is supplied from the air supply port provided at the right end of the driven shafts 7b and 7c, the protruding pin 94 moves, and the moving ring 91 and the driven shafts 7b and 7c are fixed and stored. After digital data corresponding to the angle data θa, θb, and θc is output to the D / A converters a63a, b63b, and c63c, respectively, the drive signals of the switches 1, 2, and 3 (56a to 56c) are O Then, the signals to the piezoelectric elements (1) 27a to 27c are turned on, the first pressing means 47a to 47c are pressed, the drive signals of the switches 4, 5 (56d, 56e) are turned off, and the movable ring 91 and the driven are driven. The shafts 7b and 7c are opened, and the movement amounts Xb and c of the rollers 8b and 8c are taken in by the A / D converter 103 again using the rising edge of the Z-phase pulse signal 49 as a trigger signal, and the movement amount which is the relative error data. After confirming that Xb and c are equal to or less than the set allowable error data ε, the drive signals of the switches 4 and 5 (56d and 56e) are turned ON, and the solenoid valve 104 operates to drive the right ends of the driven shafts 7b and 7c. Compressed air or the like is supplied from the air supply port provided in the section, the protruding pin 94 moves, the moving ring 91 and the driven shafts 7b and 7c are fixed, and a setting completion signal 88b is output to the host computer (not shown). N to complete the operation (S13).
According to the above configuration, the angular position of each driven shaft can be corrected even if the crossing angle formed by each driven shaft center and the drive shaft varies due to mechanical position errors due to processing, assembly errors, and the like.
[0021]
Next, second and third embodiments of the present invention will be described with reference to FIGS. A description of the same parts as those in the first embodiment is omitted. As shown in FIG. 14 which shows the relationship between the applied voltage of the piezoelectric element and the displacement amount characteristic, the relationship of the displacement amount with respect to the applied voltage of the first piezoelectric elements 27a to 27c which are the constituent elements of the first embodiment is generally. Has history characteristics. That is, when the applied voltage is increased, the amount of displacement increases accordingly, but even if the applied voltage is lowered from that state, the original trajectory is not followed, and the displacement amount Dp remains in the state where the applied voltage is 0. Therefore, when the applied voltage to the first piezoelectric elements 27a to 27c is relatively small, the residual displacement amount Dp when the first pressing means 47a to 47c is opened is very small, so there is no problem, but the applied voltages are compared. In other words, in other words, if the pressing amount of the rollers 8a to 8c against the drive shaft 1 (this is generally referred to as preload) is increased, the remaining displacement amount Dp is increased, so that there is a case where it cannot be completely released.
Therefore, in the second embodiment, as illustrated in FIG. 7A, for example, a strain gauge that detects the deformation amount by changing the resistance value in the first deformation portions 28 d to 28 f of the first pressing plates 28 a to 28 c. The first deformation amount measuring means 30a to 30c are provided, and the servo control is performed by comparing the output signal of the first deformation amount measuring means 30 (30a to 30c) with the set voltage of the constant voltage circuit.
[0022]
FIG. 8 shows a block diagram thereof. As for the output signal of the constant voltage circuit 55, the drive signal is connected to the CPU 58, and the switches 4, 5, 6 (68a to 68c) are connected to the output signal of the constant voltage circuit 55 when turned on and connected to 0VGND of the circuit when turned off. Are connected to the differential amplifiers a68a, b68b, c68c, and the output signals of the first deformation amount measuring means 30a-30c are connected to the bridge circuits a73a, b73b, c73c for detecting the resistance value change, The output signal is input to amplifiers a72a, b72b, and c72c that amplify a minute signal, and the output signal is input to the differential amplifiers a68a, b68b, and c68c, and the switch 4 inside the differential amplifiers a68a, b68b, and c68c. 5 and 6 (68a to 68c), the output signal of the constant voltage circuit 55 connected to the end, and 0VGND signal of the circuit are subtracted The output signals are input to the drive amplifiers a57a, b57b, c57c via the compensation circuits a70a, b70b, c70c and the gain adjusters a71a, b71b, c71c, and the switches 4, 5, 6 (68a to 68c). Thereafter, the first servo control means 76 is constituted by the drive amplifiers a57a, b57b, and c57c, and the output signals thereof are connected to the first piezoelectric elements 27a to 27c. The frequency characteristic between the displacement amounts of the first pressing means 47a to 47c with respect to the input signals to the drive amplifiers a57a, b57b, and c57c is a secondary system as shown in FIG. 19, and the compensation circuits a70a, b70b, and c70c are adjusted. Thus, the phase margin of 40 degrees or more and the gain margin of 15 dB or more which are stability index values of a general servo system are provided. According to the above configuration, even if the applied voltage of the first piezoelectric elements 27a to 27c is relatively large, in other words, even if the pressing amount of the rollers 8a to 8c against the drive shaft 1 is large, the first servo control means 76 can The output signal of the constant voltage circuit 55, which is the target value, the 0VGND signal of the circuit, and the output signal from the first deformation amount measuring means 30a to 30c are compared and converged to the target value, so that the residual displacement amount Dp does not occur.
[0023]
For the same reason as described in the second embodiment, the second piezoelectric elements 31a to 31c also have hysteresis characteristics. Therefore, when a large lead amount is set, it takes time for the correction operation by the voltage correction unit 67 described with reference to FIG. 6 of the first embodiment. Therefore, in the third embodiment, as shown in FIG. 7B, the second deforming portions 32d to 32f of the second pressing plates 32a to 32c constituting the second pressing means 48a to 48c are the same as in the second embodiment. Are provided with second deformation amount measuring means 34a to 34c such as strain gauges for detecting the deformation amount according to the change of the resistance value, and output signals 74d to 74d of D / A converters a63a, b63b and c63c as shown in FIG. Second servo control means 77 having the same configuration as that of the second embodiment with 74f as a target value is provided. The description of the configuration is omitted here because it overlaps with the second embodiment.
In the above configuration, the output signals of the D / A converters a63a, b63b, and c63c, which are target values, as in the second embodiment, are compared with the output signals from the second deformation amount measuring units 34a to 34c to obtain target values. Since it converges, the residual displacement amount Dp does not occur.
In the first to third embodiments, the pressing adjustment range and the crossing angle adjustment range of the driven shafts 7a to 7c and the drive shaft 1 are the first pressing means 47a to 47c and the second pressing means 48a to 48c used in the first. The piezoelectric elements 27a to 27c and the second piezoelectric elements 31a to 31c are limited to the maximum expansion / contraction amount. Therefore, in the fourth embodiment, a configuration that can cope with a large lead setting condition will be described.
[0024]
Next, a fourth embodiment of the present invention will be described with reference to FIGS. 10 (a), (b), and (c) and FIGS. 11 (a) to 11 (d) (cross-sectional views of each part in FIG. 10). The description will be made with reference to FIG. 1 according to the first embodiment. A description of the same parts as those in the first embodiment is omitted. In 4th Embodiment shown to Fig.11 (a), as for the 1st fixing plate 22, the both sides | surfaces are being fixed to the lower part of the protrusion part 13a to the feed direction of the mobile body 13, and the driven shaft 7a is the recessed part. It has guide part (1) 22a-22c in the direction which presses -7c. Furthermore, in order to move the first fixing plate 22 in the direction of pressing the first pressing plates 28a to 28c and the driven shafts 7a to 7c provided to be fitted to the respective guide portions (1) 22a to 22c. The position can be adjusted in the direction in which the driven shafts 7a to 7c are pressed by the adjusting screws (1) 29a to 29c provided on the first fixing plate 22 and the female screw portions provided on the first pressing plates 28a to 28c. And both side surfaces thereof are fitted to the guide portions (2) 22d to 22f of the first fixing plate 22 in a direction in which the driven shafts 7a to 7c are pressed in the tangential direction of the drive shaft 1 with the concave portions. Second pressing plates 32a to 32c provided as described above and adjusting screws (2) 33a to 33a provided to the first fixing plate 22 provided in a direction in which the driven shafts 7a to 7c are pressed in the tangential direction of the outer periphery of the drive shaft 1. 33c, and rear end sides of the second pressing plates 32a to 32c By, and configured to be adjustable in position in a direction of pressing the driven shaft 7a~7c the tangential direction of the drive shaft 1 the outer circumference. In addition, after the position adjustment of the first pressing plates 28a to 28c and the second pressing plates 32a to 32c, as shown in FIG. 11C, the fixtures (1) 42a to 42c and the fixture (2), respectively. 43a-43c is attached and it is set as the structure fixed to a feed direction.
In the fourth embodiment of the present invention, the concave portion of the second fixing plate 23 is also fixed by being arranged equiangularly in the circumferential direction with respect to the axis of the drive shaft 1 and provided on the driven shafts 7a to 7c. Third pressing provided with three first elastic bodies 35a to 35c (such as spheres 35d to 35f provided at the pressing end portions) such as coil springs for pressing .about.8c in a direction away from the outer periphery of the drive shaft 1. The plate 36a-36c and the 4th which provided three 2nd elastic bodies 38a-38c (the ball | bowl 38d-38f is provided in the press end part), such as a coil spring pressed in the outer periphery tangent direction of the drive shaft 1, are provided. The pressing plates 40a to 40c are provided and have the same configuration as that of the other embodiments described above. However, when the deformation strokes of the first elastic bodies 35a to 35c and the second elastic bodies 38a to 38c are sufficiently large, these pressings are used. No board is needed.
According to the above configuration, the first pressing plates 28a to 28c and the second pressing plate 32a are manually performed before the angle correction operation described in the first to third embodiments is performed for a large lead condition to be set. To 32c are adjusted in the vicinity of the set lead by the adjusting screws (1) 29a to 29c and the adjusting screws (2) 33a to 33c, and the maximum expansion and contraction amounts of the first piezoelectric elements 27a to 27c and the second piezoelectric elements 31a to 31c are adjusted. After making it enter, angle correction operation is performed.
[0025]
In the first to fourth embodiments, after the pressure of the rollers 8a to 8c against the drive shaft 1, the force called preload is not directly controlled, and the expansion / contraction amount of the first piezoelectric elements 27a to 27c is set according to the command value. Came. In this case, as described in the second problem, the current preload amount with respect to the drive shaft 1 of the rollers 8a to 8c cannot be quantitatively confirmed. In the fifth, sixth, and seventh embodiments, a configuration for controlling the preload on the drive shaft 1 of the rollers 8a to 8c will be described.
First, Embodiment 5 will be described with reference to the cross-sectional view of FIG. 12 and the circuit configuration diagram of the variable pressing control means of FIG. The first output means 64 includes a variable voltage circuit 78, a changeover switch 68 (68a to 68c) which is connected to an output signal of the variable voltage circuit 78 at one terminal of 0V and the other terminal and is turned on / off by an external signal. The third pressing means 28a to 28c, the rotation support points 24a to 24c, and the rollers 8a to 8c are used to detect the amount of deformation in the pressing direction of the driven shafts 7a to 7c at the outer peripheral portions of the driven shafts 7a to 7c. The deformation amount measuring means 46a to 46c, the pressure setting signals which are output signals 79a to 79c of the changeover switches 68a to 68c, and the current pressure amounts which are output signals 80a to 80c of the third deformation amount measuring means 46a to 46c. It comprises third servo control means 83 for servo control in comparison. In this configuration, the amount of preload applied to the drive shaft 1 by the rollers 8a to 8c provided on the driven shafts 7a to 7c is detected as the amount of deformation in the pressing direction of the driven shafts 7a to 7c. At this time, the pressing is performed within the elastic deformation of the driven shafts 7a to 7c, and it goes without saying that the relationship of the preload amount to the applied voltage to the first piezoelectric elements 27a to 27c is linear. Furthermore, in the fifth embodiment, since the output of the variable voltage circuit 78 is used as a preload setting signal, the preload amount can be manually set freely.
[0026]
Further, in the sixth embodiment, as shown in the circuit diagram of the pressing servo control means (1) in FIG. 15, the variable voltage circuit 78 and one terminal in the configuration of the first output means 64 in the fifth embodiment are set to 0V, and the other Is connected to the output signal of the variable voltage circuit 78, and the portion of the changeover switch 68 that is turned ON / OFF by an external signal is used as a D / A converter d84 connected to the CPU 58, The third deformation control means 86 includes fourth servo control means 86 that performs servo control by comparing the current pressing amounts that are output signals 80a to 80c of the third deformation amount measuring means 46a to 46c. In this configuration, the pressure release at the time of angle adjustment is a configuration in which digital data in which the output of the D / A converter d84 is 0 V is output, and the switch operation signal from the CPU 58 described in the first to fifth embodiments. There is no configuration. In this configuration, for example, if appropriate preload setting condition data is described as a constant in a program stored in the ROM 60, an appropriate preload can be set instantaneously, and preload associated with aging due to wear of rollers and drive shafts. It is not necessary to perform the readjustment work.
In the configuration of the sixth embodiment, since only one pressing setting signal is given to the first piezoelectric elements 27a to 27c of the first pressing means 47a to 47c, for example, due to processing variations of the driven shafts 7a to 7c, etc. If there is a variation in the amount of deformation at the time of pressing, or there is variation in the strain gauge used in the bridge circuit or the third deformation amount measuring means 46a to 46c, the same preload amount may not be obtained. A configuration for avoiding this will be described in a seventh embodiment.
[0027]
In the seventh embodiment, as shown in FIG. 16, the first output means 64 includes a plurality of D / A converters d84a, e84b, which independently provide pressing setting signals to the plurality of first piezoelectric elements 27a to 27c. f84c, the first pressing plates 28a to 28c, the rotation support points 24a to 24c, and the rollers 8a to 8c, and detecting the amount of deformation in the pressing direction of the driven shafts 7a to 7c at the outer peripheral portions of the driven shafts 7a to 7c. The third deformation amount measuring means 46a to 46c, the press setting signals which are the output signals 85a to 85c of the plurality of D / A converters d84a, e84b and f84c, and the outputs of the third deformation amount measuring means 46a to 46c. It is composed of fifth servo control means 87 that servo-controls the signals 80a to 80c by comparing with the current pressing amount. In this configuration, for example, the relationship between the pressing amount and the deformation amount of the driven shafts 7a to 7c is obtained in advance and grasped, and each different pressing setting signal is obtained from the plurality of D / A converters d84a, e84b, and f84c. Output.
Although not described in the first to seventh embodiments, the driven shafts 7a to 7c are connected to the pressing points of the first pressing means 47a to 47c and the rotation support as shown in the displacement enlarged mechanism diagram of the driven shaft in FIG. When the distance between the points 24a to 24c is L1, and the distance between the rotation support points 24a to 24c and the rollers 8a to 8c is L2, the displacement enlarging mechanism is configured such that L2> L1. According to this configuration, even if the expansion amount of the first piezoelectric elements 27a to 27c used for the first pressing means 47a to 47c is small, a large pressing stroke is obtained at the rolling contact end between the rollers 8a to 8c and the drive shaft 1. It goes without saying that the mechanism arranged around the drive shaft can be made small.
[0028]
【The invention's effect】
As described above, according to the invention of claim 1, it is possible to correct the variation in the crossing angle between each driven shaft and the drive shaft caused by a mechanical position error due to processing, assembly error, etc. The angle between each roller shaft core and the drive shaft is precisely set, and no slippage due to lead error occurs between the rollers of the drive shaft and each driven shaft, enabling stable feed control and improving feed accuracy. .
According to a second aspect of the present invention, the moving means includes a disc-shaped elastic plate having a roller provided on the outer periphery, an inner peripheral portion fixed to one end of the driven shaft facing one end of the moving ring, and at least the driven shaft. It is configured to have a plurality of steel balls that fit into one or more through-holes and the tip part contacts the taper part of the taper-shaped protruding pin, and moves / fixes the roller with a simple structure and detects its movement amount And the cost of the apparatus is reduced.
According to the third aspect of the present invention, the moving amount detecting means is composed of a strain gauge for detecting strain, a bridge circuit, and an amplifier, and it is possible to move / fix the roller and detect the moving amount with a simple configuration, so that the apparatus cost is low. It becomes.
According to a fourth aspect of the present invention, the first output means includes a constant voltage circuit, a change-over switch that is turned ON / OFF by an external signal, a first deformation amount measuring means provided on the first pressing plate, and an output of the change-over switch. By providing the first servo control means for servo-control by comparing the signal and the output signal of the first deformation amount measuring means, the pressing (preload) operation of the roller to the outer periphery of the drive shaft and the driving of each driven shaft Since the angle correction operation for correcting the intersection angle with the axis can be performed with high reproducibility, stable feed control can be realized and feed accuracy can be improved.
According to a fifth aspect of the present invention, the second output means includes second servo control means for performing a servo operation by comparing the output signal of the D / A converter and the output signal of the second deformation amount measuring means. As a result, the roller can be pressed (preload) to the outer periphery of the drive shaft and the angle correction operation to correct the crossing angle between each driven shaft and the drive shaft can be performed with high reproducibility. The accuracy can be improved.
[0029]
According to a sixth aspect of the present invention, the angle adjusting means includes a first pressing plate provided so as to be fitted to the first guide portion of the first fixing plate, an adjusting screw provided on the first fixing plate, and a first screw. A second pressing plate provided so as to be position-adjustable by a female screw portion provided on the pressing plate, and fitted to the second guide portion of the first fixing plate; The adjustment screw provided on the fixed plate and the second pressing plate are provided so that the position of the driven shaft can be adjusted in the direction tangential to the outer periphery of the drive shaft so that the angle correction operation can be performed even at a large crossing angle. Therefore, stable feed control can be realized in a wide range of lead conditions, and versatility as a feed component can be enhanced.
According to a seventh aspect of the present invention, the first output means is a pressing setting signal which is an output signal of a changeover switch for turning on / off the variable voltage circuit and the ground by an external signal, and an output signal of the third deformation amount measuring means. Since there is a third servo control means that performs servo control by comparing the current pressing amount, preload servo is performed with a signal that replaces the preload amount for the drive shaft of the roller with the deformation amount of the driven shaft. The preload conditions can be set instantly, the preload can be readjusted with the passage of time due to wear of the rollers and the drive shaft, and the reproducibility of the preload at the time of parts replacement can be improved and the assemblability can be improved.
[0030]
Further, in claim 8, the first output means includes one D / A converter, third deformation amount measuring means for detecting the deformation amount in the pressing direction of the driven shaft on the outer peripheral portion of the driven shaft, and D / A fourth servo control means for servo-controlling the output signal of the A converter and the output signal of the third deformation amount measuring means is provided, and the preload amount for the driving shaft of the roller is replaced with the deformation amount of the driven shaft. Since the preload servo is performed with the selected signal, the appropriate preload condition can be set instantaneously, the preload can be readjusted due to aging due to wear of the roller and drive shaft, and the reproducibility of the preload when replacing parts is also good. Therefore, the assemblability can be improved.
According to a ninth aspect of the present invention, the first output means includes fifth servo control means for performing servo control by comparing the output signals of the plurality of D / A converters with the output signals of the third deformation amount measuring means. Thus, the preload servo is performed with a signal obtained by replacing the preload amount with respect to the driving shaft of the roller with the deformation amount of the driven shaft, and the pressure setting value for each first pressing means is independently given. Even if assembly is performed with an error in the feed direction straightness of the column, which is the fixed part of the fixed guide mechanism, and the drive shaft feed direction straightness, the preload fluctuation due to the assembly error when the moving body operates in the feed direction Since there is no variation in the driving force generated on the outer periphery of each roller and the drive shaft, stable feed operation can be realized even with long stroke drive, and feed control accuracy and assemblability can be improved and simple. Guide machine Device is inexpensive in can be constructed.
According to the tenth aspect of the present invention, since the driven shaft can obtain a large pressing stroke even when the expansion and contraction amount of the piezoelectric element used for the first pressing means is small, the mechanism disposed around the drive shaft can be reduced, and the apparatus can be downsized. I can plan.
[Brief description of the drawings]
FIGS. 1A, 1B, and 1C are a top view, a right side view, and a partially broken sectional view showing a configuration of a friction drive device according to a first embodiment of the present invention.
FIGS. 2A, 2B, 2C, and 2D are sectional views taken along lines AA ′, BB ′, CC ′, and elasticity of the first embodiment of the present invention, respectively. It is structure explanatory drawing of a body part.
FIGS. 3A and 3B are cross-sectional views of the respective parts in FIG.
FIGS. 4A and 4B are detailed views of the pressing means of the present invention.
FIG. 5 is a block diagram of angle adjustment means according to an embodiment of the present invention.
FIG. 6 is a flowchart for explaining the operation of the angle adjusting means of the present invention.
7A and 7B are detailed views of pressing means according to second and third embodiments of the present invention.
FIG. 8 is a block diagram of first servo control means of the present invention.
FIG. 9 is a block diagram of second servo control means of the present invention.
FIGS. 10A, 10B, and 10C are a top view, a right side view, and a partial cross-sectional view showing a configuration of a friction drive device according to a second embodiment of the present invention.
FIGS. 11A, 11B, 11C, and 11D are cross-sectional views of parts of a second embodiment of the present invention. FIGS.
FIG. 12 is a cross-sectional view showing a configuration of a fifth embodiment of the present invention.
FIG. 13 is a block diagram of variable pressing control means according to the embodiment of the present invention.
FIG. 14 is a diagram showing the relationship between the applied voltage and displacement characteristics of the piezoelectric element of the present invention.
FIG. 15 is a configuration diagram of first pressing servo control means according to a sixth embodiment of the present invention.
FIG. 16 is a configuration diagram of second pressing servo control means according to the seventh embodiment of the present invention.
FIG. 17 is a diagram showing the relationship between the crossing angle and leads in the present invention.
FIG. 18 is a cross-sectional view of the driven shaft in the present invention.
FIG. 19 is an explanatory diagram of a transfer function of a displacement amount with respect to an input to a drive amplifier in the present invention.
FIG. 20 is a displacement enlargement mechanism diagram of a driven shaft in the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Drive shaft, 7 Drive shaft, 8 roller, 9a Rolling bearing (2), 13 Moving body, 14 Rolling bearing, 15a Light-receiving part, 15b Scale, 16 Position detection means, 18 Turntable, 19 Air spindle, 20 Motor, 21 Optical rotary encoder, 22 1st fixed plate, 23 2nd fixed plate, 89 struts, 90 base

Claims (10)

固定されたベースと、該ベース側に回転自在に支持された駆動軸と、該駆動軸の外径位置に所定の傾斜角度をもって円周方向に等角配置された複数の従動軸と、該複数の従動軸により夫々回転自在に支持され且つ前記駆動軸の外周にころがり接触するローラと、前記駆動軸の回転に伴って駆動軸の軸方向に移動すると共に前記従動軸を支持する移動体と、該移動体の送り位置を検出する位置検出手段と、を備えた摩擦駆動装置であって、
前記複数の従動軸の内の少なくとも一つの従動軸は軸線方向に移動不能に前記ローラを支持し、他の従動軸はその軸線方向に移動可能に前記ローラを支持する移動手段及びその移動量を検出する移動量検出手段と、を備え、
前記各従動軸を回動自在に支持する軸受と、前記軸受の中心である回動支持点を支点として該従動軸の他端を駆動軸外周から離間させる方向に押圧する第１の弾性体及び前記駆動軸外周の接線方向に押圧する第２の弾性体とを備え、
前記回動支持点を挟んだ前記ローラと反対側の従動軸端部に対応する前記移動体部分に固定され、前記駆動軸の軸線と直交する方向且つ前記第１の弾性体の押圧力による前記回動支持点周りのモーメント力を相殺する方向に前記従動軸を押圧する第１の押圧手段と、
前記駆動軸外周の接線方向且つ前記第２の弾性体の押圧力による前記回動支持点周りのモーメント力を相殺する方向に前記従動軸を押圧する第２の押圧手段と、
前記各構成要素の制御を行う制御部と、
前記制御部の指令により前記第１の押圧手段を押圧／開放し、前記ローラを前記他の従動軸の軸線方向に移動／固定する第１の出力手段と、
前記駆動軸の１回転当たりの原点検出信号と前記ローラの移動量検出手段の出力信号に基づいて、前記他の従動軸に対する、前記少なくとも一つの従動軸の傾き角度誤差を算出する角度誤差算出手段と、
前記角度誤差算出手段により算出された角度誤差に相当する出力信号を現在の印加信号から増減した補正信号を前記第２の押圧手段に印加する第２の出力手段を有する角度調整手段と、を備えたことを特徴とする摩擦駆動装置。A fixed base, a drive shaft rotatably supported on the base side, a plurality of driven shafts arranged equiangularly in a circumferential direction at a predetermined inclination angle at an outer diameter position of the drive shaft, and the plurality A roller that is rotatably supported by the driven shaft of each of the rollers and that is in rolling contact with the outer periphery of the drive shaft, a moving body that moves in the axial direction of the drive shaft as the drive shaft rotates, and supports the driven shaft; A position detecting means for detecting a feed position of the moving body, and a friction drive device comprising:
At least one driven shaft of the plurality of driven shafts supports the roller so that it cannot move in the axial direction, and the other driven shaft supports moving means for moving the roller in the axial direction, and a moving amount thereof. A movement amount detection means for detecting,
A bearing that rotatably supports each driven shaft, and a first elastic body that presses the other end of the driven shaft away from the outer periphery of the drive shaft with a rotation support point that is the center of the bearing as a fulcrum; A second elastic body that presses in the tangential direction of the outer periphery of the drive shaft,
It is fixed to the moving body portion corresponding to the driven shaft end opposite to the roller across the rotation support point, and the direction is perpendicular to the axis of the drive shaft and the pressing force of the first elastic body. First pressing means for pressing the driven shaft in a direction to cancel the moment force around the rotation support point;
Second pressing means for pressing the driven shaft in a direction tangential to the outer periphery of the drive shaft and in a direction that cancels the moment force around the rotation support point due to the pressing force of the second elastic body;
A control unit that controls each of the components;
First output means for pressing / releasing the first pressing means according to a command from the control unit, and moving / fixing the roller in the axial direction of the other driven shaft;
Angle error calculating means for calculating an inclination angle error of the at least one driven shaft with respect to the other driven shaft based on an origin detection signal per rotation of the drive shaft and an output signal of the roller movement amount detecting means. When,
Angle adjusting means having second output means for applying a correction signal obtained by increasing or decreasing an output signal corresponding to the angle error calculated by the angle error calculating means to the second pressing means. A friction drive device characterized by that. 前記移動手段は、前記他の従動軸の外周に配置されると共に外周に軸受を介して前記ローラを備え、且つ該ローラの軸方向両端部の内周面と前記他の従動軸の外周面との間にすべり軸受を形成する移動リングと、
前記移動リングに外周部が固着され、且つ前記他の従動軸に内周部が固着された円盤状の弾性板と、
前記他の従動軸の軸線と直交する方向に設けられた少なくとも１つ以上の貫通穴内に嵌合する複数の鋼球と、
前記他の従動軸の一端面から軸線方向に同軸状に設けられ且つ前記貫通穴と連通する穴部と、
前記穴部内に軸方向移動可能に支持されて、テーパ状の先端部にて前記複数の鋼球と接する突き出しピンと、
を備えていることを特徴とする請求項１に記載の摩擦駆動装置。The moving means is disposed on the outer periphery of the other driven shaft and includes the roller via a bearing on the outer periphery, and an inner peripheral surface at both axial ends of the roller and an outer peripheral surface of the other driven shaft. A moving ring forming a sliding bearing between
A disc-shaped elastic plate having an outer peripheral portion fixed to the moving ring and an inner peripheral portion fixed to the other driven shaft;
A plurality of steel balls fitted in at least one or more through holes provided in a direction orthogonal to the axis of the other driven shaft;
A hole provided coaxially in the axial direction from one end surface of the other driven shaft and communicating with the through hole;
A protruding pin that is supported in the hole so as to be movable in the axial direction, and is in contact with the plurality of steel balls at a tapered tip,
The friction drive device according to claim 1, further comprising: 前記移動量検出手段は、前記円盤状の弾性板の内外周間での半径方向のひずみを検出するひずみゲージと、抵抗値変化を検出するブリッジ回路と、該ブリッジ回路の信号を増幅する増幅器と、を備えたことを特徴とする請求項１又は２に記載の摩擦駆動装置。  The movement amount detecting means includes a strain gauge for detecting a radial strain between the inner and outer circumferences of the disk-shaped elastic plate, a bridge circuit for detecting a change in resistance value, and an amplifier for amplifying a signal of the bridge circuit; The friction drive device according to claim 1, further comprising: 前記第１の出力手段は、一定電圧を発生する定電圧回路と、一方の端子を０Ｖとし且つ他方の端子に前記定電圧回路の出力信号が接続され外部信号によりＯＮ／ＯＦＦする切換スイッチと、
前記第１の押圧手段に設けた第１の変形部に設けた第１の変形量測定手段と、
前記切換スイッチの出力信号である押圧伸縮設定信号と前記第１の変形量測定手段の出力信号である現在押圧伸縮量とを比較してサーボ制御する第１のサーボ制御手段と、
を備えたことを特徴とする請求項１乃至３の何れか一項に記載の摩擦駆動装置。The first output means includes a constant voltage circuit that generates a constant voltage, a change-over switch that has one terminal set to 0 V and the other terminal is connected to the output signal of the constant voltage circuit and is turned ON / OFF by an external signal;
First deformation amount measuring means provided in a first deformation portion provided in the first pressing means;
First servo control means for performing servo control by comparing a pressing expansion / contraction setting signal that is an output signal of the changeover switch and a current pressing expansion / contraction amount that is an output signal of the first deformation amount measuring means;
The friction drive device according to any one of claims 1 to 3, further comprising: 前記第２の出力手段は、ＣＰＵからのデジタル信号をアナログ信号に変換するＤ／Ａ変換器と、前記第２の押圧手段に設けた第２の変形部に設けた第２の変形量測定手段と、前記Ｄ／Ａ変換器の出力信号である押圧伸縮設定信号と前記第２の変形量測定手段の出力信号である現在押圧伸縮量とを比較してサーボ動作を行う第２のサーボ制御手段と、
を備えたことを特徴とする請求項１に記載の摩擦駆動装置。The second output means includes a D / A converter that converts a digital signal from the CPU into an analog signal, and a second deformation amount measuring means provided in a second deformation portion provided in the second pressing means. And a second servo control means for performing a servo operation by comparing a pressing expansion / contraction setting signal which is an output signal of the D / A converter and a current pressing expansion / contraction amount which is an output signal of the second deformation amount measuring means. When,
The friction drive apparatus according to claim 1, further comprising: 前記角度調整手段は、前記移動体に固定された第１の固定板と、第１の固定板に設けた第１の案内部に両側面が嵌合するよう設けられた第１の押圧板と、前記移動体に固定され且つ前記従動軸を押圧して位置調整するために前記第１の固定板に設けた第１の調整ネジ及び前記第１の押圧板に設けた雌ネジ部と、前記移動体に支持され且つ前記従動軸を前記駆動軸外周の接線方向に押圧すると共に前記第１の固定板に設けた第２の案内部に嵌合するよう設けられた第２の押圧板と、を備え、
前記従動軸を前記駆動軸外周の接線方向に押圧するために前記第１の固定板に設けた第２の調整ネジと、前記第２の押圧板の後端側面と、によって、前記従動軸を前記駆動軸外周の接線方向に押圧して位置調整可能となるように構成されていることを特徴とする請求項１に記載の摩擦駆動装置。The angle adjusting means includes a first fixing plate fixed to the moving body , a first pressing plate provided so that both side surfaces are fitted to a first guide portion provided on the first fixing plate, A first adjusting screw provided on the first fixing plate and a female screw portion provided on the first pressing plate for adjusting the position by pressing the driven shaft and being fixed to the movable body, A second pressing plate that is supported by a moving body and that presses the driven shaft in a tangential direction of the outer periphery of the driving shaft and is fitted to a second guide portion provided on the first fixed plate; With
The second adjusting screw provided on the first fixing plate for pressing the driven shaft in the tangential direction of the outer periphery of the drive shaft, and the rear end side surface of the second pressing plate, the driven shaft is 2. The friction drive device according to claim 1, wherein the friction drive device is configured so that the position can be adjusted by pressing in a tangential direction of the outer periphery of the drive shaft. 前記第１の出力手段は、電圧を変更可能とした構成の可変電圧回路と、一方の端子を０Ｖとし且つ他方の端子に前記可変電圧回路の出力信号が接続され外部信号によりＯＮ／ＯＦＦする切換スイッチと、
前記第１の押圧板と前記回動支持点とローラ間にあって、前記従動軸の押圧方向への変形量を検出する第３の変形量測定手段と、
前記切換スイッチの出力信号である押圧設定信号と前記第３の変形量測定手段の出力信号である現在押圧量とを比較してサーボ制御する第３のサーボ制御手段と、
を備えたことを特徴とする請求項１乃至４の何れか一項に記載の摩擦駆動装置。The first output means includes a variable voltage circuit configured to be able to change the voltage, and a switching in which one terminal is set to 0 V and the output signal of the variable voltage circuit is connected to the other terminal and is turned ON / OFF by an external signal. A switch,
A third deformation amount measuring unit which is between the first pressing plate, the rotation support point, and the roller and detects a deformation amount in the pressing direction of the driven shaft;
Third servo control means for performing servo control by comparing a pressing setting signal that is an output signal of the changeover switch with a current pressing amount that is an output signal of the third deformation amount measuring means;
The friction drive device according to any one of claims 1 to 4, further comprising: 前記第１の出力手段は、ＣＰＵからのデジタル信号をアナログ信号に変換する１つのＤ／Ａ変換器と、前記第３の変形量測定手段と、
前記１つのＤ／Ａ変換器の出力信号である押圧設定信号と第３の変形量測定手段の出力信号である現在押圧量とを比較してサーボ制御する第４のサーボ制御手段と、
を備えていることを特徴とする請求項１乃至４の何れか一項に記載の摩擦駆動装置。The first output means includes one D / A converter for converting a digital signal from the CPU into an analog signal, the third deformation amount measuring means,
A fourth servo control means for performing servo control by comparing a press setting signal that is an output signal of the one D / A converter and a current press amount that is an output signal of the third deformation amount measuring means;
5. The friction drive device according to claim 1, wherein the friction drive device is provided. 前記第１の出力手段は、複数の圧電素子への押圧設定信号を独立に与えるためにＣＰＵからのデジタル信号をアナログ信号に変換する複数のＤ／Ａ変換器と、第３の変形量測定手段と、
前記複数のＤ／Ａ変換器の出力信号である押圧設定信号と前記第３の変形量測定手段の出力信号である現在押圧量とを比較してサーボ制御する第５のサーボ制御手段と、
を備えていることを特徴とする請求項１乃至４の何れか一項に記載の摩擦駆動装置。The first output means includes a plurality of D / A converters for converting a digital signal from the CPU into an analog signal in order to independently provide pressing setting signals to the plurality of piezoelectric elements, and a third deformation amount measuring means. When,
A fifth servo control means for performing servo control by comparing a pressing setting signal that is an output signal of the plurality of D / A converters with a current pressing amount that is an output signal of the third deformation amount measuring means;
5. The friction drive device according to claim 1, wherein the friction drive device is provided. 前記従動軸は、前記第１の押圧手段の押圧点と前記回動支持点間距離をＬ１、前記回動支持点とローラ間距離をＬ２とした時に、Ｌ２＞Ｌ１の条件を満足する第３の変形量測定手段変位拡大機構を形成していることを特徴とする請求項１乃至９の何れか一項に記載の摩擦駆動装置。  The driven shaft satisfies the condition of L2> L1 when the distance between the pressing point of the first pressing means and the rotation support point is L1, and the distance between the rotation support point and the roller is L2. The friction drive device according to any one of claims 1 to 9, wherein a deformation amount measuring means displacement magnifying mechanism is formed.
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