JP3933460B2 - Drive device - Google Patents

Description

【００３８】
この数１におけるｆｒｏは電気機械変換素子２６の両電極２６１，２６２間におけるフリー共振周波数（電気機械変換素子２６自体の電極間方向における共振周波数）、ｍｐは電気機械変換素子２６の質量、ｍｆは駆動部材２８の質量をそれぞれ表わしている。なお、支持部材２４の質量は、共振系における電気機械変換素子２６の共振周波数ｆｒに関係するが、支持部材２４の質量は電気機械変換素子２６及び駆動部材２８の各質量ｍｐ，ｍｆを加算したものに比べて十分大きな値を有しており、共振周波数ｆｒに与える影響は小さいので演算パラメータとして考慮する必要はない。また、係合部材３０は、電気機械変換素子２６の共振時には駆動部材２８に対して滑りを生じて実質的に共振系の要素として考慮する必要はないので、上記数１の演算パラメータとしては含まれていない。
【００３９】
図７は、電気機械変換素子２６に印加される駆動回路部１６からの駆動電圧のパルス波形と、電気機械変換素子２６の伸縮による変位との対応関係を示す図で、同図（ａ）は図４（ａ）に示す駆動電圧が印加された場合であり、同図（ｂ）は図４（ｂ）に示す駆動電圧が印加された場合をそれぞれ示している。なお、電気機械変換素子２６の伸縮による変位波形は、レーザードップラー振動計により測定したものを概略的に示したものである。
【００４０】
このように、電気機械変換素子２６に図４（ａ）に示す駆動電圧が印加された場合は電気機械変換素子２６の変位波形が緩慢な立ち上がり部Ｃと急峻な立ち下がり部Ｄとを有する鋸歯形状となり、電気機械変換素子２６に図４（ｂ）に示す駆動電圧が印加された場合は電気機械変換素子２６の変位波形が急峻な立ち上がり部Ｅと緩慢な立ち下がり部Ｆとを有する鋸歯形状となっていることが確認された。
【００４１】
すなわち、電気機械変換素子２６の変位が図７（ａ）に示すような緩慢な立ち上がり部Ｃを有する波形を呈するとき（すなわち、電気機械変換素子２６が緩やかに伸長するとき）は、係合部材３０が駆動部材２８と共に繰出し方向に移動し、電気機械変換素子２６の変位が図７（ａ）に示すような急峻な立下り部Ｄを有する波形を呈するとき（すなわち、電気機械変換素子２６が急激に縮小するとき）は、駆動部材２８が戻り方向に移動しても係合部材３０は駆動部材２８上をスリップして略同位置に留まることになる。このため、図７（ａ）に示す駆動電圧が電気機械変換素子２６に繰り返し印加されることで、係合部材３０は繰出し方向に間欠的に移動することになる。
【００４２】
また、電気機械変換素子２６の変位が図７（ｂ）に示すような急峻な立ち上がり部Ｅを有する波形を呈するとき（すなわち、電気機械変換素子２６が急激に伸長するとき）は、駆動部材２８が繰出し方向に移動しても係合部材３０は駆動部材２８上をスリップして略同位置に留まることになり、電気機械変換素子２６の変位が図７（ｂ）に示すような緩慢な立下り部Ｆを有する波形を呈するとき（すなわち、電気機械変換素子２６が緩やかに縮小するとき）は、係合部材３０が駆動部材２８と共に戻り方向に移動することになる。このため、図７（ｂ）に示す駆動電圧が電気機械変換素子２６に繰り返し印加されることで、係合部材３０は戻り方向に間欠的に移動することになる。
【００４３】
このように、例えば図４（ａ），（ｂ）に示す駆動電圧が電気機械変換素子２６に印加された場合、電気機械変換素子２６の変位波形が鋸歯形状となるのは次のような理由による。つまり、矩形波は基本波である正弦波と複数次の高調波とからなるものであるが、駆動電圧の駆動周波数ｆｄが電気機械変換素子２６の共振周波数ｆｒに対して０．３倍よりも大きく１．５倍よりも小さいとき（０．３×ｆｒ＜ｆｄ＜１．５×ｆｒ）、系における電気機械変換素子２６の共振周波数ｆｒの影響を受けて矩形波を形成している高調波成分のうち３次以上の高次の高調波のゲインが大きく減衰し、電気機械変換素子２６に印加される駆動電圧が実質的に基本波と２次高調波とからなる波形（鋸歯形状の波形）を有するものとなるからである。
【００４４】
すなわち、図８に示すような矩形波の駆動電圧（例えば、駆動周波数ｆｄが電気機械変換素子２６の共振周波数ｆｒに対して０．３倍よりも大きく１．５倍よりも小さいもの）の１パルス分の成分は、フーリエ変換することにより図９に示すような基本波ｆ１に対してｆ２，ｆ３，…，ｆｎの複数次の高調波を有するものとして表わすことができる。一方、支持部材２４及び駆動部材２８が固着された状態での電気機械変換素子２６の共振特性は、図１０に示すように、図９の３次高調波ｆ３以上の周波数領域ではゲインが大きく減衰したものとなる。
【００４５】
このため、電気機械変換素子２６に図８に示す矩形波の駆動電圧を印加すると、電気機械変換素子２６の変位波形（振動波形）は３次以上の高調波ｆ３，…，ｆｎ成分が大きく減衰されたものとなり、図１１に示すように実質的に基本波ｆ１及び第２高調波ｆ２成分のみを有するものとなる。この図１１に示す成分を有する電気機械変換素子２６の変位波形はフーリエ逆変換することにより求めることができ、図１２に示すような鋸歯形状を呈するものとなる。
【００４６】
また、駆動電圧のデューティ比のある値を境にして係合部材３０の移動方向が繰出し方向と戻り方向間で反転するのは、そのデューティ比に対応して基本波に対する２次高調波の位相がずれ、基本波と２次高調波とからなる鋸歯波形における立ち上がり部と立ち下がり部の各傾斜が変化することになるからである。すなわち、デューティ比Ｄが０．０５＜Ｄ＜０．４５の範囲内にあるときには、２次高調波の位相のずれが大きくなって緩慢な立ち上がり部と急峻な立ち下がり部を有する鋸歯波形となることから係合部材３０は繰出し方向に移動し、デューティ比Ｄが０．５５＜Ｄ＜０．９５の範囲内にあるときには、２次高調波の位相のずれが小さくなって急峻な立ち上がり部と緩慢な立ち下がり部を有する鋸歯波形となることから係合部材３０は繰出し方向に移動する。
【００４７】
因みに、図１３（ａ）に示すように、駆動電圧の駆動周波数ｆｄが電気機械変換素子２６の共振周波数ｆｒの０．１倍（ｆｄ＝０．１×ｆｒ）となるように設定し、駆動電圧のデューティ比が０．３になるように設定した場合、電気機械変換素子２６の変位は矩形波における立ち上がり部の後の平坦部と立ち下がり部の後の平坦部にリンギングが生じるのみで鋸歯波形とはならず、係合部材３０は停止したままであった。また、図１３（ｂ）に示すように、駆動電圧の駆動周波数ｆｄが電気機械変換素子２６の共振周波数ｆｒの０．１倍（ｆｄ＝０．１×ｆｒ）となるように設定し、駆動電圧のデューティ比が０．７になるように設定した場合、電気機械変換素子２６の変位は図１３（ａ）の場合と同様に矩形波における立ち上がり部の後の平坦部と立ち下がり部の後の平坦部にリンギングが生じるのみで鋸歯波形とはならず、係合部材３０は停止したままであった。
【００４８】
次に、図１４を参照して本発明の駆動装置１０の動作説明を行う。すなわち、この図１４は、図３に示す駆動回路部１６を制御する制御信号出力部１６４から出力されて各スイッチング素子Ｑ１乃至Ｑ６に印加される駆動パルス（駆動制御信号）と、第１の駆動部１２及び第２の駆動部１４の各電気機械変換素子２６に印加される駆動電圧の波形とを示す図である。
【００４９】
この図１４に示す各電気機械変換素子２６に印加される駆動電圧は、上述したように矩形波からなるものであり、その駆動周波数ｆｄが支持部材２４及び駆動部材２８の固着された状態での電気機械変換素子２６の共振周波数ｆｒに対し、０．７倍に設定されると共に、繰出し方向における波形についてはデューティ比Ｄが０．３に設定され、戻り方向の波形についてはデューティ比Ｄが０．７に設定されたものである。この駆動電圧が電気機械変換素子２６に印加されることで係合部材３０は繰出し方向と戻り方向とに移動することになる。なお、図１４において、第１の駆動部１２については係合部材３０が繰出し方向と戻り方向とに移動する場合を示しており、第２の駆動部１４については係合部材３０が繰出し方向のみに移動する場合を示している。
【００５０】
この図１４に示すように、駆動装置１０の駆動時には、例えば、制御信号出力部１６４からハイレベル（Ｈ）の期間とローレベル（Ｌ）の期間とが同一であるデューティ比が０.５の駆動制御信号Ｓｃ３が第１のスイッチ部１６２と第２のスイッチ部１６３の共有の回路の一部であるスイッチング素子Ｑ３に入力されるとき、ハイレベル（Ｈ）の期間とローレベル（Ｌ）の期間とが同一であるデューティ比が０.５で駆動制御信号Ｓｃ３とは逆相にある駆動制御信号Ｓｃ４が第１のスイッチ部１６２と第２のスイッチ部１６３の共有の回路の一部であるスイッチング素子Ｑ４に入力される。
【００５１】
そして、第１の駆動部１２について、スイッチング素子Ｑ３に入力される駆動制御信号Ｓｃ３がハイレベル（Ｈ）の期間中にのみ制御信号出力部１６４からハイレベル（Ｈ）の駆動制御信号Ｓｃ２がスイッチング素子Ｑ２に入力される。ここで、駆動制御信号Ｓｃ３がハイレベル（Ｈ）の期間中は、スイッチング素子Ｑ１に入力される駆動制御信号Ｓｃ１はローレベル（Ｌ）となるように設定されており、駆動制御信号Ｓｃ１と駆動制御信号Ｓｃ３とが同時にハイレベル（Ｈ）となることで接続点ｃと接続点ｄとに接続された電気機械変換素子２６の両端が同電位にならないようになっている。
【００５２】
また、スイッチング素子Ｑ４に入力される駆動制御信号Ｓｃ４がハイレベル（Ｈ）の期間中にのみ制御信号出力部１６４からハイレベル（Ｈ）の駆動制御信号Ｓｃ１がスイッチング素子Ｑ１に入力される。ここで、駆動制御信号Ｓｃ４がハイレベル（Ｈ）の期間中は、スイッチング素子Ｑ２に入力される駆動制御信号Ｓｃ２はローレベル（Ｌ）となるように設定されており、駆動制御信号Ｓｃ２と駆動制御信号Ｓｃ４とが同時にハイレベル（Ｈ）となることで接続点ｃと接続点ｄとに接続された電気機械変換素子２６の両端が短絡されないようになっている。
【００５３】
このように、所定のデューティ比に設定された駆動制御信号Ｓｃ２，Ｓｃ３及びＳｃ１，Ｓｃ４が制御信号出力部１６４から連続して出力されることにより、スイッチング素子Ｑ２，Ｑ３及びＱ１，Ｑ４が交互にオン、オフを繰り返すことになる。すなわち、スイッチング素子Ｑ２，Ｑ３がオンのときには電気機械変換素子２６には＋Ｖｐの電圧が印加され、スイッチング素子Ｑ１，Ｑ４がオンのときには電気機械変換素子２６には−Ｖｐの電圧が印加されることになる結果、電気機械変換素子２６には見掛け上、電源電圧Ｖｐの２倍（２Ｖｐ）電圧が印加されたことになり、係合部材３０の移動速度を速くすることができて駆動装置１０を効果的に動作させることができる。
【００５４】
なお、本実施形態では、駆動電圧のデューティ比Ｄを０．３とすることで係合部材３０が繰出し方向に移動し、デューティ比Ｄを０．７とすることで係合部材３０が戻り方向に移動するように設定されている。すなわち、デューティ比を０.３に設定することで係合部材３０を繰出し方向に駆動させる場合には、駆動制御信号Ｓｃ１がローレベル（Ｌ）となる期間を駆動制御信号Ｓｃ４がローレベル（Ｌ）となる期間よりも所定の時間（デューティ比を０.３にするのに必要な時間）ｔ１だけ長くなるように設定されている。これにより、その時間ｔ１には電気機械変換素子２６に駆動電源１６１から駆動電圧−Ｖｐが直接印加されない状態となるが、電気機械変換素子２６はその対向電極２６１，２６２間が駆動電圧−Ｖｐで充電された状態となっているため、実質的に駆動電源１６１から駆動電圧−Ｖｐが印加されたのと同様の状態となって不都合が生じることはない。
【００５５】
また、デューティ比を０.７に設定することで係合部材３０を戻り方向に駆動させる場合には、駆動制御信号Ｓｃ２がローレベル（Ｌ）となる期間を駆動制御信号Ｓｃ３がローレベル（Ｌ）となる期間よりも所定の時間（デューティ比を０.７にするのに必要な時間）ｔ２だけ長くなるように設定されている。これにより、その時間ｔ２には電気機械変換素子２６に駆動電源１６１から駆動電圧Ｖｐが直接印加されない状態となるが、電気機械変換素子２６はその対向電極２６１，２６２間が駆動電圧Ｖｐで充電された状態となっているため、実質的に駆動電源１６１から駆動電圧Ｖｐが印加されたのと同様の状態となって不都合が生じることはない。
【００５６】
このように、駆動制御信号Ｓｃ１がローレベル（Ｌ）となる期間を駆動制御信号Ｓｃ４がローレベル（Ｌ）となる期間よりも所定の時間ｔ１だけ長くなるように設定すると共に、駆動制御信号Ｓｃ２がローレベル（Ｌ）となる期間を駆動制御信号Ｓｃ３がローレベル（Ｌ）となる期間よりも所定の時間ｔ２だけ長くなるように設定しているのは、次のような理由による。すなわち、駆動制御信号Ｓｃ３が供給される第３のスイッチ回路１６７及び駆動制御信号Ｓｃ４が供給される第４のスイッチ回路１６８が第２のスイッチ部１６３と共有する回路であるため、第２のスイッチ部１６３が第２の駆動部１４を第１の駆動部１２とは逆方向にも駆動できるようにする必要があることから駆動制御信号Ｓｃ３，Ｓｃ４のデューティ比を本実施形態では０.５に設定していることによる。
【００５７】
また、第２の駆動部１４について、スイッチング素子Ｑ３に入力される駆動制御信号Ｓｃ３がハイレベル（Ｈ）の期間中にのみ制御信号出力部１６４からハイレベル（Ｈ）の駆動制御信号Ｓｃ６がスイッチング素子Ｑ６に入力される。ここで、駆動制御信号Ｓｃ３がハイレベル（Ｈ）の期間中は、スイッチング素子Ｑ５に入力される駆動制御信号Ｓｃ５はローレベル（Ｌ）となるように設定されており、駆動制御信号Ｓｃ３と駆動制御信号Ｓｃ５とが同時にハイレベル（Ｈ）となることで接続点ｄと接続点ｅとに接続された電気機械変換素子２６の両端が同電位とならないようになっている。
【００５８】
また、スイッチング素子Ｑ４に入力される駆動制御信号Ｓｃ４がハイレベル（Ｈ）の期間中にのみ制御信号出力部１６４からハイレベル（Ｈ）の駆動制御信号Ｓｃ５がスイッチング素子Ｑ５に入力される。ここで、駆動制御信号Ｓｃ４がハイレベル（Ｈ）の期間中は、スイッチング素子Ｑ６に入力される駆動制御信号Ｓｃ６はローレベル（Ｌ）となるように設定されており、駆動制御信号Ｓｃ４と駆動制御信号Ｓｃ６とが同時にハイレベル（Ｈ）となることで接続点ｄと接続点ｅとに接続された電気機械変換素子２６の両端が短絡されないようになっている。
【００５９】
このように、所定のデューティ比に設定された駆動制御信号Ｓｃ３，Ｓｃ６及びＳｃ４，Ｓｃ５が制御信号出力部１６４から連続して出力されることにより、スイッチング素子Ｑ３，Ｑ６及びＱ４，Ｑ５が交互にオン、オフを繰り返すことになる。すなわち、スイッチ素子Ｑ３，Ｑ６がオンのときには電気機械変換素子２６には＋Ｖｐの電圧が印加され、スイッチ素子Ｑ４，Ｑ５がオンのときには電気機械変換素子２６には−Ｖｐの電圧が印加されることになる結果、電気機械変換素子２６には見掛け上、電源電圧Ｖｐの２倍（２Ｖｐ）電圧が印加されたことになり、係合部材３０の移動速度を速くすることができて駆動装置１０を効果的に動作させることができる。
【００６０】
ここで、本実施形態では、駆動電圧のデューティ比Ｄを０．３とすることで係合部材３０が繰出し方向に移動し、デューティ比Ｄを０．７とすることで係合部材３０が戻り方向に移動するように設定されている（なお、図では、第２の駆動部１４は繰出し方向に駆動される場合のみを示している。）。すなわち、デューティ比を０.３に設定することで係合部材３０を繰出し方向に駆動させる場合には、駆動制御信号Ｓｃ５がローレベル（Ｌ）となる期間を駆動制御信号Ｓｃ４がローレベル（Ｌ）となる期間よりも所定の時間（デューティ比を０.３にするのに必要な時間）ｔ１だけ長くなるように設定されている。これにより、その時間ｔ１には電気機械変換素子２６に駆動電源１６１から駆動電圧−Ｖｐが直接印加されない状態となるが、電気機械変換素子２６はその対向極２６２，２６２間が駆動電圧−Ｖｐで充電された状態となっているため、実質的に駆動電源１６１から駆動電圧−Ｖｐが印加されたのと同様の状態となって不都合が生じることはない。
【００６１】
このように、駆動制御信号Ｓｃ５がローレベル（Ｌ）となる期間を駆動制御信号Ｓｃ４がローレベル（Ｌ）となる期間よりも所定の時間ｔ１だけ長くなるように設定しているのは、第１の駆動部１２の場合と同様の理由による。すなわち、駆動制御信号Ｓｃ３が供給される第３のスイッチ回路１６７及び駆動制御信号Ｓｃ４が供給される第４のスイッチ回路１６８が第１のスイッチ部１６２と共有する回路であるため、第１のスイッチ回路１６２が第１の駆動部１２を第２の駆動部１４とは逆方向にも駆動できるようにする必要があることから駆動制御信号Ｓｃ３，Ｓｃ４のデューティ比を本実施形態では０.５に設定していることによる。
【００６２】
なお、第１の駆動部１２及び第２の駆動部１４は、図２に示すような素子固定式構造のものではなく、例えば、図１５に示すような自走式構造のものであっても上記の駆動回路部１６により駆動することができる。図１５（ａ）は自走式構造の第１の駆動部１２’及び第２の駆動部１４’の分解斜視図であり、図１５（ｂ）はその正面図である。
【００６３】
すなわち、この図１５に示す駆動部１２’，１４’は、位置固定される係合部材（ベース部材）４０と移動部材４２とから構成されている。係合部材４０は、基板４４と、基板４４の略中央位置に所定の間隔をおいて対向配置され、板ばね等の弾性部材４６，４８により取り付けられた一対の狭持部材５０，５２と、基板４４の左右両端部に取り付けられた一対のガイド部材５４，５６とを備えている。各ガイド部材５４，５６の外側面には、回転自在の複数のボール部材５８，６０が取り付けられている。
【００６４】
移動部材４２は、駆動体６３と、この駆動体６３に一体に取り付けられた移動体６５とから構成されている。駆動体６３は、支持部材６７、電気機械変換素子６９及び駆動部材７１から構成されている。支持部材６７は、電気機械変換素子６９及び駆動部材７１を保持するものであり、直方体の軸方向両端部６７１，６７２及び略中央の仕切壁６７３を残して刳り貫くことにより形成された第１の収容空間６７４及び第２の収容空間６７５を有している。この第１の収容空間６７４には、電気機械変換素子６９がその伸縮方向を支持部材６７の軸方向と一致させて収容されている。また、第２の収容空間６７５には、駆動部材７１が軸方向に移動可能に収容されている。
【００６５】
電気機械変換素子６９は、図２に示す電気機械変換素子２６と同様に構成されたものであり、その伸縮方向（積層方向）である一方端面（例えば、正極側）が第１の収容空間６７４の一方端部６７１側端面に固着されている。駆動部材７１は、支持部材６７の左右両側に膨出する膨出部７１１が中央部に一体形成された軸体からなるもので、この膨出部７１１が第２の収容空間６７５に位置すると共に、仕切壁６７３に形成された貫通孔を介して第１の収容空間６７４内に突出した端部は電気機械変換素子６９の他方端面（例えば、負極側）に固着され、支持部材６７の他方端部６７２に形成された貫通孔を介して第２の収容空間６７５の外部に突出した端部は自由端とされている。
【００６６】
移動体６５は、平板部６５１と、平板部６５１の左右両側に下方に伸びる側壁部６５２，６５３が形成されると共に、各側壁部６５２，６５３の内側に摺動部材６５４，６５５が形成されたもので、移動部材４２における支持部材６７の上面にねじ部材６５６により固定されている。
【００６７】
このように構成された移動部材４２は、駆動部材７１の膨出部７１１が係合部材４０の一対の挟持部材５０，５２間に移動可能に挟持されることで係合部材４０に組み付けられることになる。すなわち、係合部材４０が図２の係合部材３０に対応するものであり、この係合部材４０が駆動部材７１に対して所定の摩擦力で結合され、駆動部１２’，１４’が構成されることになる。
【００６８】
この駆動部１２’，１４’では、駆動回路部１６から例えば図４（ａ）に示す波形を有する駆動電圧が電気機械変換素子６９に印加されて電気機械変換素子６９が緩やかに伸長すると、駆動部材７１が静止した状態で支持部材６７が係合部材４０の一方側に移動し、その後に電気機械変換素子６９が急激に縮小すると、支持部材６７が静止した状態で駆動部材７１が狭持部材５０，５２による摩擦力に打ち勝って係合部材４０の一方側に移動する。この繰り返し動作により支持部材６７が移動体６５と共に、係合部材４０の一方側に間欠的に移動することになる。
【００６９】
また、駆動回路部１６から例えば図４（ｂ）に示す波形を有する駆動電圧が電気機械変換素子６９に印加されて電気機械変換素子６９が急激に伸長すると、支持部材６７が静止した状態で駆動部材７１が狭持部材５０，５２による摩擦力に打ち勝って係合部材４０の他方側に移動し、その後に電気機械変換素子６９が緩やかに縮小すると駆動部材７１が静止した状態で支持部材６７が係合部材４０の他方側に移動する。この繰り返し動作により支持部材６７が移動体６５と共に、係合部材４０の他方側に間欠的に移動することになる。
【００７０】
本発明の実施形態に係る駆動装置は、上記のように、第１の駆動部１２，１２’の電気機械変換素子２６，６９を駆動する第１のスイッチ部１６２と、第２の駆動部１４，１４’の電気機械変換素子２６，６９を駆動するスイッチ部であって一部の回路が第１のスイッチ部１６２の一部の回路を共有する第２のスイッチ部１６３とを備えて構成されている。このため、駆動回路部を構成するための部品点数が削減されることから同一のシステム内において２つの駆動対象物を個別に駆動させる場合でもシステムの小型化を促進し得る駆動装置を実現することができる。また、駆動回路部を構成するための部品点数が削減されるため、駆動装置のコストダウンも可能となる。
【００７１】
なお、本発明は、上記実施形態のものに限定されるものではなく、種々の変形態様を必要に応じて採用することが可能である。例えば、図３に示す駆動回路部１６の場合では、第１，第２のスイッチ部１６２，１６３の第２，第４，第６のスイッチング素子Ｑ２，Ｑ４，Ｑ６と接地との間にそれぞれ所定の抵抗値を有する抵抗素子を接続する回路構成とすることができる。また、スイッチング素子としてＭＯＳＦＥＴを用いるようにしているが、これに限るものではない。例えば、バイポーラトランジスタを用いたりすることも可能である。
【００７２】
また、上記実施形態では、制御信号出力部１６４から出力される駆動制御信号のうち、第１のスイッチ部１６２と第２のスイッチ部１６３の共有の回路である第３のスイッチ回路１６７に供給される駆動制御信号Ｓｃ３と第４のスイッチ回路１６８に供給される駆動制御信号Ｓｃ４とは互いに逆相で、デューティ比がそれぞれ０.５に設定されたものであるが、これに限るものではない。例えば、そのデューティ比を第１，第２の駆動部１２，１４（あるいは１２’，１４’）が繰出し方向及び戻り方向の両方向に駆動可能となる範囲内で変更することも可能である。また、そのデューティ比を第１，第２の駆動部１２，１４（あるいは１２’，１４’）の繰出し方向及び戻り方向の駆動方向に応じて異なる値に設定することもできる。
【００７３】
また、上記実施形態では、それぞれの電気機械変換素子に矩形波からなる駆動電圧を印加するようにしているが、これに限るものではない。例えば、第２のスイッチ回路１６６、第４のスイッチ回路１６８及び第６のスイッチ回路１７０に、抵抗素子とスイッチング素子との直列回路をそれぞれ並列接続しておき、これらスイッチ回路と直列回路の何れかを選択的に駆動させることでそれぞれの電気機械変換素子に鋸歯形状の駆動電圧が印加されるようにしてもよい。このようにした場合、鋸歯形状の駆動電圧の立ち上がり部を緩慢にして立ち下がり部を急峻にすることで係合部材３０を支持部材２４に対し繰出し方向に相対移動させることができ、立ち上がり部を急峻にして立ち下がり部を緩慢にすることで係合部材３０を支持部材２４に対し戻り方向に相対移動させることができる。
【００７４】
【発明の効果】
以上説明したように、本発明によれば、第１の電気機械変換素子を駆動するための第１のスイッチ部の一部の回路と、第２の電気機械変換素子を駆動するための第２のスイッチ部の一部の回路とが互いに共有され、駆動制御手段が、第１のスイッチ部と第２のスイッチ部とに共用されているスイッチング素子に、前記第１の駆動部と前記第２の駆動部とを同時に駆動させることが可能なデューティ比の駆動制御信号を与えるので、同一のシステム内において２つの駆動対象物を個別に駆動させる場合でもシステムの小型化を促進し得る駆動装置を実現することができる。
【図面の簡単な説明】
【図１】 本発明の一実施形態に係る駆動装置の全体構成を概略的に示す図である。
【図２】 図１に示す駆動装置の駆動部の構成例を示す斜視図である。
【図３】 図１に示す駆動装置の駆動回路部の構成例を示すブロック図である。
【図４】 図３に示す駆動回路部により形成される駆動パルスの波形を示す図で、（ａ）はデューティ比が０．３になるように設定されたもの、（ｂ）はデューティ比が０．７になるように設定されたものである。
【図５】 図１に示す駆動装置におけるｆｄ／ｆｒと係合部材の移動速度との関係を示す図である。
【図６】 図１に示す駆動装置における駆動電圧のデューティ比と係合部材の移動速度との関係を示す図である。
【図７】 図１に示す駆動装置の電気機械変換素子に印加される駆動電圧と、電気機械変換素子の伸縮による変位波形との関係を示す図で、（ａ）は駆動電圧のデューティ比が０．３になるように設定された場合のもの、（ｂ）は駆動電圧のデューティ比が０．７になるように設定された場合のものである。
【図８】 電気機械変換素子に印加する矩形波からなる駆動電圧を示す図である。
【図９】 図８に示す駆動電圧をフーリエ変換することにより求めた基本波及び高調波成分を示す図である。
【図１０】 支持部材及び駆動部材が固着された状態での電気機械変換素子の共振特性を示す図である。
【図１１】 図１０に示す共振特性を有する電気機械変換素子に図８に示す駆動電圧を印加した場合の基本波及び高調波成分を示す図である。
【図１２】 図１１に示す基本波及び高調波成分をフーリエ逆変換することにより求めた電気機械変換素子の変位波形を示す図である。
【図１３】 本発明の範囲外の駆動周波数を有する駆動電圧と電気機械変換素子の伸縮による変位波形との関係を示す図で、（ａ）は駆動電圧のデューティ比が０．３になるように設定したもの、（ｂ）は駆動電圧のデューティ比が０．７になるように設定したものである。
【図１４】 図３に示す駆動回路部の動作説明をするためのタイミングチャートである。
【図１５】 図１に示す駆動装置における駆動部の別の構成例を示す図で、（ａ）はその分解斜視図、（ｂ）はその正面図である。
【図１６】 従来例の駆動装置の構成を概略的に示す図である。
【符号の説明】
１０ 駆動装置
１２，１２’ 第１の駆動部
１４，１４’ 第２の駆動部
１６ 駆動回路部
１８ 制御部（駆動制御手段）
２４，６７ 支持部材
２６，６９ 電気機械変換素子
２８，７１ 駆動部材
３０，４０ 係合部材
１６１ 駆動電源
１６２ 第１のスイッチ部
１６３ 第２のスイッチ部
１６４ 制御信号出力部
１６５ 第１のスイッチ回路
１６６ 第２のスイッチ回路
１６７ 第３のスイッチ回路
１６８ 第４のスイッチ回路
１６９ 第５のスイッチ回路
１７０ 第６のスイッチ回路
Ｑ１ 第１のスイッチング素子
Ｑ２ 第２のスイッチング素子
Ｑ３ 第３のスイッチング素子
Ｑ４ 第４のスイッチング素子
Ｑ５ 第５のスイッチング素子
Ｑ６ 第６のスイッチング素子[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a driving apparatus suitable for driving an XY moving stage, a camera photographing lens, a projection lens of an overhead projector, a binocular lens, a probe of a scanning tunneling electron microscope, and the like.
[0002]
[Prior art]
  In recent years, an engagement member to which a driving object such as a photographic lens is attached is coupled to a rod-shaped driving member so as to have a predetermined frictional force, and an electromechanical conversion element including a piezoelectric element is provided at one end of the driving member. A drive device composed of an impact-type piezoelectric actuator fixedly constructed has been developed. For example, FIG. 16 is a diagram illustrating a schematic configuration of a driving device for adjusting the photographing lens position of the camera.
[0003]
  The drive device 100 in FIG. 16 couples the engagement member 104 with a predetermined frictional force to a rod-like drive member 103 driven by a drive electromechanical transducer 102 made of a piezoelectric element attached to a support member 101. The drive unit 105 configured as described above and the drive circuit unit 106 that drives the electromechanical conversion element 102 by applying drive voltages in both forward and reverse directions to the electromechanical conversion element 102 are provided.
[0004]
  The electromechanical conversion element 102 expands and contracts in accordance with the drive voltage applied via the drive circuit unit 106, and is attached to the support member 101 whose one end in the expansion / contraction direction that is the direction between the positive electrode and the negative electrode is fixed. The other end is fixed to one end in the axial direction of the drive member 103 while being fixed. The engaging member 104 has a photographing lens L, which is a driving object, fixed to a predetermined location, and is movable along the axial direction on the driving member 103.
[0005]
  The drive circuit unit 106 supplies a drive voltage composed of a rectangular wave to the electromechanical conversion element 102. The engagement member 104 is connected to the drive member 103 with respect to the support member 101 whose position is fixed by changing its duty ratio. In this case, the movement is made in the direction of the arrow a1 which is the feeding direction (direction away from the electromechanical conversion element 102) and the direction of the arrow a2 which is the return direction (direction approaching the electromechanical conversion element 102).
[0006]
[Problems to be solved by the invention]
  By the way, when two driving objects are individually driven in the same system (device), it is necessary to use two independent driving devices 100 corresponding to the number of the driving objects. For this reason, it is necessary to secure a space for disposing the two drive devices 100 independent from each other in the same system, and there is a possibility that the system is restricted in size.
[0007]
  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a driving device that can promote downsizing of the system even when two driving objects are individually driven in the same system. And
[0008]
[Means for Solving the Problems]
  In order to achieve the above object, the invention of claim 1 includes a first electromechanical transducer having a counter electrode, a first support member fixed to one electrode side of the first electromechanical transducer, A first drive comprising a first drive member fixed to the other electrode side of the first electromechanical transducer and a first engagement member engaged with the first drive member with a predetermined frictional force. Part, a second electromechanical transducer having a counter electrode, a second support member fixed to one electrode side of the second electromechanical transducer, and the other electrode of the second electromechanical transducer A second driving member that is fixed to the side, a second driving member that is engaged with the second driving member with a predetermined frictional force, and a driving power source that outputs a DC voltage Connected between this drive power supply and groundIncludes multiple switching elementsA first switch unit, connected between the drive power supply and ground;Includes multiple switching elementsSwitch part and someSwitching elementIs a part of the first switch section.Shared with switching elementsThe second switch section and the first switch section are driven and controlled, and the DC voltage output from the drive power supply is applied to the first electromechanical transducer as a rectangular wave first drive voltage. And a control signal output unit configured to drive the second switch unit to change the DC voltage output from the drive power supply into a second drive voltage of a rectangular wave and apply the second voltage to the second electromechanical transducer. And a drive circuit unit including the control signal output unit, and a duty ratio of the first drive voltage is changed by controlling the drive of the control signal output unit so that the first electromechanical conversion element has different speeds in the expansion direction and the reduction direction. The first electromechanical conversion element is extended in the extension direction by moving the first support member and the first engagement member relative to each other by expanding and contracting at the same time and changing the duty ratio of the second drive voltage. When And a second support member and a drive control means for relatively moving the second engagement member by expanding and contracting at different rates in the small direction,The drive control means controls the drive of the control signal output unit from the control signal output unit.The first switch unit and the second switch unit are provided.A drive control signal having a predetermined duty ratio to be supplied to each switching element is output.A drive control signal having a duty ratio capable of causing the switching element shared by the first switch unit and the second switch unit to drive the first drive unit and the second drive unit simultaneously. give RuIt is characterized by that.
[0009]
  According to this configuration, a part of the circuit of the first switch unit for driving the first electromechanical conversion element and a part of the second switch unit for driving the second electromechanical conversion element This circuit is shared with each other, so that the number of parts for configuring the drive circuit unit is reduced. For this reason, the drive device which can promote the miniaturization of the system is realized even when two driving objects are individually driven in the same system. In addition, the cost of the driving device can be reduced by reducing the number of parts for configuring the driving circuit unit.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
  FIG. 1 is a block diagram schematically showing a basic configuration of a drive device including an impact type piezoelectric actuator according to an embodiment of the present invention. In this figure, the drive device 10 includes a first drive unit 12, a second drive unit 14, a drive circuit unit 16 that drives the first drive unit 12 and the second drive unit 14, and the overall operation. And a control unit 18 for controlling the control. The first driving unit 12 and the second driving unit 14 have the same configuration.
[0011]
  FIG. 2 is a perspective view illustrating a configuration example of the first driving unit 12 and the second driving unit 14. In this figure, each of the first drive unit 12 and the second drive unit 14 has an element-fixed structure, and includes a support member 24, an electromechanical transducer 26, a drive member 28, and an engagement member 30. ing.
[0012]
  The support member 24 holds the electromechanical conversion element 26 and the drive member 28, and is formed by piercing the inside leaving the axial both ends 241 and 242 and the substantially central partition wall 243. A first accommodation space 244 and a second accommodation space 245 are provided. In addition, a round hole 246 is bored at the center position of the other end 242 of the support member 24, and a round hole 247 is bored at the center position of the partition wall 243.
[0013]
  The electromechanical transducer 26 is configured by, for example, laminating a plurality of piezoelectric substrates having a predetermined thickness between each piezoelectric substrate via an unillustrated electrode, and a positive electrode (one side as a counter electrode on the outer surface) Electrode) 261 and a negative electrode (the other electrode) 262 are provided. The electromechanical conversion element 26 is housed in the first housing space 244 in a state in which the expansion / contraction direction, which is the direction between the opposing electrodes, coincides with the axial direction of the support member 24, and one end surface (for example, the positive electrode 261 side) is The first accommodation space 244 is fixed to the end surface on the one end 241 side.
[0014]
  The drive member 28 is formed in a rod shape with a round cross section, and the second end of the drive member 28 passes through the round hole 246 of the other end 242 of the support member 24 and the round hole 247 of the partition wall 243. It is accommodated in the accommodation space 245 so as to be movable along the axial direction. In addition, the drive member 28 has an end protruding into the first accommodation space 244 fixed to the other end surface (for example, the negative electrode 262 side) of the electromechanical transducer 26 and the other end 242 of the support member 24. The end protruding to the outside is pressed by the leaf spring 32 with a predetermined spring pressure and is biased toward the electromechanical conversion element 26 side. The reason why the drive member 28 is biased by the leaf spring 32 is to stabilize the axial displacement of the drive member 28 based on the expansion and contraction operation of the electromechanical transducer 26.
[0015]
  The engaging member 30 includes a base portion 302 having mounting portions 301 and 301 on both sides in the axial direction of the drive member 28, and a sandwiching member 303 mounted between the mounting portions 301 and 301. The base portion 302 is a first member. 2 is loosely fitted to the drive member 28 in the housing space 245, and the engaging member 30 comes into contact with the peripheral surface of the drive member 28 by being pressed by the leaf spring 304, so that the engagement member 30 has a predetermined frictional force. And is coupled to the drive member 28. As a result, the engagement member 30 can move along the axial direction of the drive member 28 when a driving force larger than the frictional force acts on the engagement member 30. The engaging member 30 is attached with a driving object L (FIG. 1) such as a photographing lens.
[0016]
  FIG. 3 is a diagram illustrating a configuration example of the drive circuit unit 16. In this figure, the drive circuit unit 16 is connected between a drive power supply 161 that outputs a DC voltage, a first switch unit 162 connected between the drive power supply 161 and the ground, and between the drive power supply 161 and the ground. The second switch unit 163 in which a part of the circuit shares a part of the circuit of the first switch unit 162, and the first switch unit 162 and the second switch unit 163 are driven and controlled. A control signal for converting the DC voltage output from the power supply 161 into a rectangular wave driving voltage and applying the same to the electromechanical transducer 26 of the first driver 12 and the electromechanical transducer 26 of the second driver 14. And an output unit 164.
[0017]
  The drive power supply 161 is composed of a DC-DC converter or the like whose one end is grounded. The first switch unit 162 includes a first switching element Q1 that is a MOSFET between the connection point a to which the drive voltage + Vp is supplied from the drive power supply 161 and the connection point b that is grounded. A first series circuit composed of a switch circuit 165 and a second switch circuit 166 having a second switching element Q2 which is a MOSFET, and a third switch circuit 167 and a MOSFET having a third switching element Q3 which is a MOSFET. A second series circuit composed of a fourth switch circuit 168 having a fourth switching element Q4 is connected.
[0018]
  The second switch unit 163 includes a third switch unit 162 that constitutes the first switch unit 162 between the connection point a to which the drive voltage + Vp is supplied from the drive power supply 161 and the connection point b that is grounded. A second series circuit including a third switch circuit 167 having a switching element Q3 and a fourth switch circuit 168 having a fourth switching element Q4 constituting the first switch unit 162; A fifth switch circuit 169 having a switching element Q5 and a third series circuit including a sixth switch circuit 170 having a sixth switching element Q6 which is a MOSFET are connected to each other.
[0019]
  That is, the second series circuit including the third switch circuit 167 having the third switching element Q3 and the fourth switch circuit 168 having the fourth switching element Q4 includes the first switch unit 162 and the second switch circuit 168. This is a circuit shared by the switch unit 163.
[0020]
  The control signal output unit 164 is configured to output drive control signals Sc1, Sc2, Sc3, Sc4, Sc5, and Sc6, which are drive pulses supplied to the first to sixth switch circuits 165 to 170. It is. In the present embodiment, the first to sixth switching elements Q1 to Q6 constituting the first to sixth switch circuits 165 to 170 are each composed of an N-channel FET, and are supplied to the respective gates. Turns on when the control signals Sc1 to Sc6 are at a high level.
[0021]
  Between the connection point c of the first switch circuit 165 and the second switch circuit 166 and the connection point d of the third switch circuit 167 and the fourth switch circuit 168 in the drive circuit unit 16 configured in this way. In addition, the electromechanical conversion element 26 of the first drive unit 12 is connected to form a bridge circuit. Here, the other end surface (for example, the negative electrode 262 side) of the electromechanical conversion element 26 of the first drive unit 12 is connected to the connection point c, and the one end surface (for example, the positive electrode 261 side) is connected to the connection point d. It has become so.
[0022]
  In addition, the second switch circuit 167 and the fourth switch circuit 168 in the drive circuit section 16 are connected between the connection point d of the fifth switch circuit 169 and the sixth switch circuit 170 and the second switch circuit 168. The electromechanical conversion element 26 of the drive unit 14 is connected to form a bridge circuit. Here, one end face (for example, the positive electrode 261 side) of the electromechanical conversion element 26 of the second drive unit 12 is connected to the connection point d, and the other end face (for example, the negative electrode 262 side) is connected to the connection point e. It has become so.
[0023]
  In the drive circuit unit 16 configured as described above, the second switch circuit 166 and the third switch circuit 167 apply the drive voltage + Vp to the electromechanical conversion element 26 of the first drive unit 12 from one side. The first drive circuit is configured to apply and charge between the counter electrodes 261 and 262 of the electromechanical transducer 26, and the first switch circuit 165 and the fourth switch circuit 168 are connected to the first drive unit 12. A second drive circuit that charges between the counter electrodes 261 and 262 of the electromechanical conversion element 26 by applying a drive voltage + Vp from the other side to the mechanical conversion element 26 is configured.
[0024]
  The third switch circuit 167 and the sixth switch circuit 170 apply the drive voltage + Vp from one side to the electromechanical conversion element 26 of the second drive unit 14 to oppose the electromechanical conversion element 26. A third drive circuit that charges between the electrodes 261 and 262 is configured, and the fourth switch circuit 168 and the fifth switch circuit 169 are on the other side with respect to the electromechanical conversion element 26 of the second drive unit 14. Thus, the fourth drive circuit is configured to apply the drive voltage + Vp to charge between the counter electrodes 261 and 262 of the electromechanical conversion element 26.
[0025]
  As described above, the first switch unit 162 and the electromechanical conversion element 26 of the first drive unit 12 form a bridge circuit, and the second switch unit 163 and the electromechanical conversion element of the second drive unit 14 are configured. 26, a voltage of −Vp to + Vp (that is, a voltage of 2Vp) is applied to each electromechanical conversion element 26 from the drive power supply 161, so that it is output from the drive power supply 161. Even if the driving voltage + Vp is low, there is an advantage that the driving device 10 having a large displacement can be obtained.
[0026]
  Returning to FIG. 1, the control unit 18 includes a CPU (Central Processing Unit) that performs arithmetic processing, a ROM (Read-Only Memory) that stores processing programs, various data, and the like, and a RAM that temporarily stores data (RAM) Random Access Memory), and a signal input from an unillustrated position sensor or the like that detects the positions of the engaging member 30 of the first driving unit 12 and the engaging member 30 of the second driving unit 14, respectively. The control signal output unit 164 (FIG. 3) of the drive circuit unit 16 outputs a drive pulse having a predetermined duty ratio based on the first drive circuit (the second switch circuit 166 and the third switch). Circuit 167) and the second drive circuit (configured by the first switch circuit 165 and the fourth switch circuit 168) and the third drive circuit (third switch circuit 16). And the sixth a switch circuit 170) and drives the fourth driving circuit (constituted by the fourth switch circuit 168 and the fifth switch circuit 169) alternately.
[0027]
  That is, the control unit 18 controls the drive of the control signal output unit 164 (FIG. 3), whereby the first drive circuit composed of the second switch circuit 166 and the third switch circuit 167 shown in FIG. A second drive circuit composed of one switch circuit 165 and a fourth switch circuit 168, a third drive circuit composed of a third switch circuit 167 and a sixth switch circuit 170, and a fourth switch circuit Drive control means for driving the fourth drive circuit composed of 168 and the fifth switch circuit 169 is configured.
[0028]
  Next, the principle of the driving operation of the driving circuit unit 16 applied to the driving apparatus 10 of the present invention will be described with reference to FIGS. Here, FIG. 4 shows drive voltages applied to the electromechanical transducer 26 of the first drive unit 12 and the electromechanical transducer 26 of the second drive unit 14 by the drive circuit unit 16. An example of a pulse waveform that can move the support member 24 and the engagement member 30 relative to each other by making the displacement waveform when the conversion element 26 expands and contracts into a sawtooth shape is shown.
[0029]
  That is, FIG. 4A shows a drive applied to the electromechanical transducer 26 for moving the engagement member 30 in the arrow a1 direction (FIG. 1) which is the feeding direction (direction away from the electromechanical transducer 26). This is a voltage pulse waveform, and the drive frequency fd of the drive voltage is 0.7 times (fd) the resonance frequency fr (for example, 60 KHz) of the electromechanical transducer 26 in a state where the support member 24 and the drive member 28 are fixed. = 0.7 × fr), and the duty ratio D (D = B / A) is set to 0.3.
[0030]
  FIG. 4B shows the drive applied to the electromechanical transducer 26 for moving the engagement member 30 in the direction of arrow a2 (FIG. 1) which is the return direction (direction approaching the electromechanical transducer 26). This is a voltage pulse waveform, and the drive frequency fd of the drive voltage is 0.7 times the resonance frequency fr of each electromechanical transducer 26 in a state where the support member 24 and the drive member 28 are fixed (fd = 0.7). × fr), and the duty ratio D (D = B / A) is set to 0.7.
[0031]
  The drive frequency fd and the duty ratio D of the drive voltage are set as described above because the drive voltage with respect to the resonance frequency fr of the electromechanical transducer 26 in a state where the support member 24 and the drive member 28 are fixed. The ratio of the frequency fd (fd / fr) and the moving speed of the engaging member 30 have a relationship as shown in the characteristic diagram of FIG. 5 and the duty ratio D of the driving voltage formed of a rectangular wave. This is based on the fact that the moving direction (feeding direction and returning direction) of the combined member 30 has a relationship as shown in the characteristic diagram of FIG.
[0032]
  The characteristic diagram shown in FIG. 5 has four types (the resonance frequency fr of the electromechanical conversion element 26 in a state where the support member 24 and the drive member 28 are fixed, and the form (structure) are different. The first to fourth drive devices are configured, and for each of these drive devices, the ratio (fd / fr) of the frequency fd of the drive voltage to the resonance frequency fr of the electromechanical transducer 26 and the moving speed of the engagement member 30 The correspondence is measured.
[0033]
  This characteristic diagram is for the case where the duty ratio D of the drive voltage composed of a rectangular wave is 0.3 (when the engagement member 30 moves in the feeding direction), but the duty ratio D is 0.7. In the case of (when the engagement member 30 moves in the return direction), it is confirmed that when the duty ratio D is in the range of 0.05 to 0.95, the relationship is substantially the same. Yes.
[0034]
  As is clear from the characteristic diagram shown in FIG. 5, when the value of fd / fr is in the range of 0.3 to 1.5, although there is a drop in the movement speed in some areas. While the engaging member 30 is substantially movable, the engaging member 30 is immovable when the value of fd / fr is less than 0.3 or exceeds 1.5. Therefore, the frequency fd of the drive voltage with respect to the resonance frequency fr of the electromechanical transducer 26 is set as appropriate within the range of 0.3 × fr <fd <1.5 × fr as necessary as well as that shown in FIG. can do. When the value of fd / fr is in the range of 0.6 to 1.2, all of the first to fourth driving devices 10 can operate sufficiently.
[0035]
  The characteristic diagram shown in FIG. 6 is obtained by measuring the correspondence between the duty ratio D of the drive voltage formed of a rectangular wave and the moving direction (feeding direction and returning direction) of the engaging member 30. As is apparent from this figure, when the duty ratio D is in the range of 0.05 to 0.45 (0.05 <D <0.45), the engaging member 30 moves in the feeding direction, and the duty ratio is When D is in the range of 0.55 to 0.95 (0.55 <D <0.95), the engagement member 30 moves in the return direction. Therefore, the duty ratio D can be appropriately set within the range of 0.05 <D <0.45 or 0.55 <D <0.95 as required, as well as that shown in FIG.
[0036]
  The resonance frequency fr of the electromechanical conversion element 26 in a state where the support member 24 and the drive member 28 are fixed is obtained by the following formula.
[0037]
[Expression 1]

[0038]
  In Equation 1, fro is a free resonance frequency between the electrodes 261 and 262 of the electromechanical transducer 26 (resonance frequency in the direction between the electrodes of the electromechanical transducer 26 itself), mp is the mass of the electromechanical transducer 26, and mf is The mass of the drive member 28 is represented respectively. The mass of the support member 24 is related to the resonance frequency fr of the electromechanical transducer 26 in the resonance system, but the mass of the support member 24 is the sum of the masses mp and mf of the electromechanical transducer 26 and the drive member 28. Since it has a sufficiently large value compared to the above-mentioned one and has little influence on the resonance frequency fr, it is not necessary to consider it as a calculation parameter. Further, since the engaging member 30 does not need to be considered as an element of the resonance system due to slippage with respect to the driving member 28 at the time of resonance of the electromechanical transducer 26, it is included as the calculation parameter of the above formula 1. Not.
[0039]
  FIG. 7 is a diagram showing a correspondence relationship between the pulse waveform of the drive voltage applied from the drive circuit unit 16 applied to the electromechanical transducer 26 and the displacement due to the expansion and contraction of the electromechanical transducer 26. FIG. FIG. 4A shows the case where the drive voltage is applied, and FIG. 4B shows the case where the drive voltage shown in FIG. 4B is applied. Note that the displacement waveform due to the expansion and contraction of the electromechanical transducer 26 is schematically shown as measured by a laser Doppler vibrometer.
[0040]
  As described above, when the drive voltage shown in FIG. 4A is applied to the electromechanical transducer 26, the sawtooth having the rising portion C and the steep falling portion D where the displacement waveform of the electromechanical transducer 26 is slow. When the drive voltage shown in FIG. 4B is applied to the electromechanical transducer 26, the sawtooth shape has a sharp rising portion E and a slow falling portion F of the electromechanical transducer 26. It was confirmed that
[0041]
  That is, when the displacement of the electromechanical conversion element 26 exhibits a waveform having a slow rising portion C as shown in FIG. 7A (that is, when the electromechanical conversion element 26 extends gently), the engagement member 30 moves in the feeding direction together with the drive member 28, and the displacement of the electromechanical transducer 26 exhibits a waveform having a steep falling portion D as shown in FIG. When the drive member 28 moves in the return direction, the engagement member 30 slips on the drive member 28 and stays at substantially the same position. For this reason, when the drive voltage shown in FIG. 7A is repeatedly applied to the electromechanical transducer 26, the engaging member 30 moves intermittently in the feeding direction.
[0042]
  When the displacement of the electromechanical conversion element 26 exhibits a waveform having a steep rising portion E as shown in FIG. 7B (that is, when the electromechanical conversion element 26 expands rapidly), the drive member 28 is driven. The engagement member 30 slips on the drive member 28 and stays at substantially the same position even if it moves in the feeding direction, and the displacement of the electromechanical transducer 26 is slow as shown in FIG. When the waveform having the descending portion F is exhibited (that is, when the electromechanical conversion element 26 is gradually reduced), the engagement member 30 moves in the return direction together with the drive member 28. For this reason, when the drive voltage shown in FIG. 7B is repeatedly applied to the electromechanical transducer 26, the engagement member 30 moves intermittently in the return direction.
[0043]
  As described above, for example, when the drive voltage shown in FIGS. 4A and 4B is applied to the electromechanical transducer 26, the displacement waveform of the electromechanical transducer 26 has a sawtooth shape for the following reason. by. That is, the rectangular wave is composed of a sine wave that is a fundamental wave and a plurality of higher harmonics, but the drive frequency fd of the drive voltage is more than 0.3 times the resonance frequency fr of the electromechanical transducer 26. When the frequency is larger than 1.5 times (0.3 × fr <fd <1.5 × fr), the harmonic forming the rectangular wave under the influence of the resonance frequency fr of the electromechanical transducer 26 in the system Among the components, the gain of the third and higher harmonics is greatly attenuated, and the drive voltage applied to the electromechanical transducer 26 is a waveform (a sawtooth waveform) substantially consisting of a fundamental wave and a second harmonic. ).
[0044]
  That is, a rectangular wave drive voltage as shown in FIG. 8 (for example, one having a drive frequency fd greater than 0.3 times and less than 1.5 times the resonance frequency fr of the electromechanical transducer 26). The component for the pulse can be expressed as having a plurality of higher harmonics of f2, f3,..., Fn with respect to the fundamental wave f1 as shown in FIG. On the other hand, as shown in FIG. 10, the resonance characteristics of the electromechanical transducer 26 with the support member 24 and the drive member 28 fixed are greatly attenuated in the frequency region above the third harmonic f3 in FIG. Will be.
[0045]
  For this reason, when the rectangular-wave drive voltage shown in FIG. 8 is applied to the electromechanical transducer 26, the displacement waveform (vibration waveform) of the electromechanical transducer 26 is greatly attenuated by the third and higher harmonics f3,. As shown in FIG. 11, it has substantially only the fundamental wave f1 and the second harmonic f2 component. The displacement waveform of the electromechanical transducer 26 having the components shown in FIG. 11 can be obtained by inverse Fourier transform, and has a sawtooth shape as shown in FIG.
[0046]
  In addition, the movement direction of the engagement member 30 is reversed between the feeding direction and the return direction at a certain value of the duty ratio of the drive voltage. The phase of the second harmonic relative to the fundamental wave corresponds to the duty ratio. This is because the slopes of the rising part and the falling part in the sawtooth waveform composed of the fundamental wave and the second harmonic change. That is, when the duty ratio D is in the range of 0.05 <D <0.45, the phase shift of the second harmonic becomes large, resulting in a sawtooth waveform having a slow rising portion and a steep falling portion. Therefore, the engaging member 30 moves in the feeding direction, and when the duty ratio D is in the range of 0.55 <D <0.95, the phase shift of the second harmonic becomes small and the steep rising portion Since the sawtooth waveform has a slow falling part, the engaging member 30 moves in the feeding direction.
[0047]
  Incidentally, as shown in FIG. 13A, the drive frequency fd of the drive voltage is set to be 0.1 times the resonance frequency fr of the electromechanical transducer 26 (fd = 0.1 × fr), and the drive When the voltage duty ratio is set to be 0.3, the displacement of the electromechanical conversion element 26 is a sawtooth only because ringing occurs in the flat part after the rising part and the flat part after the falling part in the rectangular wave. The corrugation did not occur, and the engaging member 30 remained stopped. Further, as shown in FIG. 13B, the drive frequency fd of the drive voltage is set to be 0.1 times the resonance frequency fr of the electromechanical transducer 26 (fd = 0.1 × fr), and the drive When the voltage duty ratio is set to be 0.7, the displacement of the electromechanical transducer 26 is the same as in FIG. 13A, after the flat part and the falling part after the rising part in the rectangular wave. Only the ringing occurs in the flat part of the plate, and the sawtooth waveform does not occur, and the engaging member 30 remains stopped.
[0048]
  Next, the operation of the driving device 10 of the present invention will be described with reference to FIG. That is, FIG. 14 shows a drive pulse (drive control signal) output from the control signal output unit 164 for controlling the drive circuit unit 16 shown in FIG. 3 and applied to each of the switching elements Q1 to Q6, and the first drive. It is a figure which shows the waveform of the drive voltage applied to each electromechanical transducer 26 of the part 12 and the 2nd drive part 14. FIG.
[0049]
  The drive voltage applied to each electromechanical transducer 26 shown in FIG. 14 is a rectangular wave as described above, and the drive frequency fd is in a state where the support member 24 and the drive member 28 are fixed. The resonance frequency fr is set to 0.7 times the resonance frequency fr of the electromechanical transducer 26, the duty ratio D is set to 0.3 for the waveform in the feeding direction, and the duty ratio D is set to 0 for the waveform in the return direction. .7. By applying this drive voltage to the electromechanical conversion element 26, the engagement member 30 moves in the feeding direction and the return direction. In FIG. 14, the first drive unit 12 shows a case where the engaging member 30 moves in the feeding direction and the return direction, and the second driving unit 14 has the engaging member 30 only in the feeding direction. The case of moving to is shown.
[0050]
  As shown in FIG. 14, when the driving apparatus 10 is driven, for example, a high-level (H) period and a low-level (L) period from the control signal output unit 164 have the same duty ratio of 0.5. When the drive control signal Sc3 is input to the switching element Q3 which is a part of the shared circuit of the first switch unit 162 and the second switch unit 163, the high level (H) period and the low level (L) The drive control signal Sc4 having the same period and a duty ratio of 0.5 and having a phase opposite to that of the drive control signal Sc3 is a part of a circuit shared by the first switch unit 162 and the second switch unit 163. Input to switching element Q4.
[0051]
  For the first drive unit 12, the high-level (H) drive control signal Sc2 is switched from the control signal output unit 164 only during the period when the drive control signal Sc3 input to the switching element Q3 is high level (H). Input to the element Q2. Here, during the period in which the drive control signal Sc3 is at the high level (H), the drive control signal Sc1 input to the switching element Q1 is set to be at the low level (L), and the drive control signal Sc1 and the drive are driven. Since the control signal Sc3 is simultaneously at the high level (H), both ends of the electromechanical transducer 26 connected to the connection point c and the connection point d are not set to the same potential.
[0052]
  Further, the high-level (H) drive control signal Sc1 is input to the switching element Q1 from the control signal output unit 164 only during the period when the drive control signal Sc4 input to the switching element Q4 is high-level (H). Here, while the drive control signal Sc4 is at the high level (H), the drive control signal Sc2 input to the switching element Q2 is set to be at the low level (L), and the drive control signal Sc2 and the drive are driven. The control signal Sc4 is simultaneously set to the high level (H), so that both ends of the electromechanical transducer 26 connected to the connection point c and the connection point d are not short-circuited.
[0053]
  In this way, the drive control signals Sc2, Sc3 and Sc1, Sc4 set at a predetermined duty ratio are continuously output from the control signal output unit 164, whereby the switching elements Q2, Q3 and Q1, Q4 are alternately arranged. Repeated on and off. That is, a voltage of + Vp is applied to the electromechanical transducer 26 when the switching elements Q2 and Q3 are on, and a voltage of −Vp is applied to the electromechanical transducer 26 when the switching elements Q1 and Q4 are on. As a result, a voltage (2Vp) twice the power supply voltage Vp is apparently applied to the electromechanical conversion element 26, and the moving speed of the engagement member 30 can be increased so that the drive device 10 can be operated. It can be operated effectively.
[0054]
  In this embodiment, the engagement member 30 moves in the feeding direction by setting the duty ratio D of the drive voltage to 0.3, and the engagement member 30 is returned in the return direction by setting the duty ratio D to 0.7. Is set to move to. That is, when the engagement member 30 is driven in the feeding direction by setting the duty ratio to 0.3, the drive control signal Sc4 is set to the low level (L) during the period in which the drive control signal Sc1 is set to the low level (L). ) Is set to be longer by a predetermined time (time required for setting the duty ratio to 0.3) t1 than the period of time). As a result, the driving voltage −Vp is not directly applied from the driving power supply 161 to the electromechanical conversion element 26 at the time t1, but the electromechanical conversion element 26 has a driving voltage −Vp between the counter electrodes 261 and 262. Since it is in a charged state, it is substantially the same state as when the drive voltage -Vp is applied from the drive power supply 161, and there is no inconvenience.
[0055]
  When the engagement member 30 is driven in the return direction by setting the duty ratio to 0.7, the drive control signal Sc3 is set to the low level (L) during the period in which the drive control signal Sc2 is set to the low level (L). ) Is set to be longer by a predetermined time (time required for setting the duty ratio to 0.7) t2. As a result, the drive voltage Vp is not directly applied to the electromechanical conversion element 26 from the drive power supply 161 at the time t2, but the electromechanical conversion element 26 is charged between the counter electrodes 261 and 262 with the drive voltage Vp. Therefore, the drive voltage Vp is substantially the same as that applied from the drive power supply 161, and there is no inconvenience.
[0056]
  In this way, the period during which the drive control signal Sc1 is at the low level (L) is set to be longer by the predetermined time t1 than the period during which the drive control signal Sc4 is at the low level (L), and the drive control signal Sc2 The reason why the period during which the drive control signal Sc3 is at the low level (L) is set to be longer by the predetermined time t2 than the period during which the drive control signal Sc3 is at the low level (L). That is, since the third switch circuit 167 supplied with the drive control signal Sc3 and the fourth switch circuit 168 supplied with the drive control signal Sc4 are circuits shared by the second switch unit 163, the second switch Since it is necessary for the unit 163 to be able to drive the second drive unit 14 in the opposite direction to the first drive unit 12, the duty ratio of the drive control signals Sc3 and Sc4 is set to 0.5 in this embodiment. It depends on what is set.
[0057]
  Further, for the second drive unit 14, the high-level (H) drive control signal Sc6 is switched from the control signal output unit 164 only during the period when the drive control signal Sc3 input to the switching element Q3 is high level (H). Input to element Q6. Here, while the drive control signal Sc3 is at the high level (H), the drive control signal Sc5 input to the switching element Q5 is set to be at the low level (L), and the drive control signal Sc3 and the drive are driven. Since the control signal Sc5 becomes high level (H) at the same time, both ends of the electromechanical transducer 26 connected to the connection point d and the connection point e are not set to the same potential.
[0058]
  Further, the high-level (H) drive control signal Sc5 is input to the switching element Q5 from the control signal output unit 164 only during the period when the drive control signal Sc4 input to the switching element Q4 is high-level (H). Here, during the period in which the drive control signal Sc4 is at the high level (H), the drive control signal Sc6 input to the switching element Q6 is set to be at the low level (L), and the drive control signal Sc4 and the drive are driven. Since both the control signal Sc6 and the control signal Sc6 are simultaneously at a high level (H), both ends of the electromechanical transducer 26 connected to the connection point d and the connection point e are not short-circuited.
[0059]
  In this way, the drive control signals Sc3, Sc6 and Sc4, Sc5 set at a predetermined duty ratio are continuously output from the control signal output unit 164, whereby the switching elements Q3, Q6 and Q4, Q5 are alternately arranged. Repeated on and off. That is, a voltage of + Vp is applied to the electromechanical conversion element 26 when the switch elements Q3 and Q6 are on, and a voltage of −Vp is applied to the electromechanical conversion element 26 when the switch elements Q4 and Q5 are on. As a result, a voltage (2Vp) twice the power supply voltage Vp is apparently applied to the electromechanical conversion element 26, and the moving speed of the engagement member 30 can be increased so that the drive device 10 can be operated. It can be operated effectively.
[0060]
  Here, in this embodiment, the engagement member 30 moves in the feeding direction by setting the duty ratio D of the drive voltage to 0.3, and the engagement member 30 returns by setting the duty ratio D to 0.7. It is set so as to move in the direction (in the figure, only the case where the second driving unit 14 is driven in the feeding direction is shown). That is, when the engagement member 30 is driven in the feeding direction by setting the duty ratio to 0.3, the drive control signal Sc4 is set to the low level (L) during the period in which the drive control signal Sc5 is set to the low level (L). ) Is set to be longer by a predetermined time (time required for setting the duty ratio to 0.3) t1 than the period of time). As a result, the drive voltage −Vp is not directly applied from the drive power supply 161 to the electromechanical conversion element 26 at the time t1, but the electromechanical conversion element 26 has a drive voltage −Vp between the counter electrodes 262 and 262. Since it is in a charged state, it is substantially the same state as when the drive voltage -Vp is applied from the drive power supply 161, and there is no inconvenience.
[0061]
  As described above, the period in which the drive control signal Sc5 is at the low level (L) is set to be longer by the predetermined time t1 than the period in which the drive control signal Sc4 is at the low level (L). For the same reason as in the case of the first driving unit 12. That is, since the third switch circuit 167 supplied with the drive control signal Sc3 and the fourth switch circuit 168 supplied with the drive control signal Sc4 are circuits shared by the first switch unit 162, the first switch Since it is necessary for the circuit 162 to be able to drive the first drive unit 12 in the opposite direction to the second drive unit 14, the duty ratio of the drive control signals Sc3 and Sc4 is set to 0.5 in this embodiment. It depends on what is set.
[0062]
  The first drive unit 12 and the second drive unit 14 are not of the element fixed structure as shown in FIG. 2, but may be of a self-propelled structure as shown in FIG. It can be driven by the drive circuit section 16 described above. FIG. 15A is an exploded perspective view of the first driving unit 12 ′ and the second driving unit 14 ′ having a self-propelled structure, and FIG. 15B is a front view thereof.
[0063]
  That is, the drive units 12 ′ and 14 ′ shown in FIG. 15 are composed of an engaging member (base member) 40 and a moving member 42 that are fixed in position. The engaging member 40 is disposed to face the substrate 44 at a substantially central position with a predetermined interval, and a pair of holding members 50 and 52 attached by elastic members 46 and 48 such as leaf springs, A pair of guide members 54 and 56 attached to both left and right ends of the substrate 44 are provided. A plurality of freely rotatable ball members 58 and 60 are attached to the outer surfaces of the guide members 54 and 56.
[0064]
  The moving member 42 includes a driving body 63 and a moving body 65 attached to the driving body 63 integrally. The drive body 63 includes a support member 67, an electromechanical conversion element 69, and a drive member 71. The support member 67 holds the electromechanical conversion element 69 and the drive member 71, and is formed by punching through the rectangular parallelepiped axial ends 671, 672 and the substantially central partition wall 673. A housing space 674 and a second housing space 675 are provided. In the first accommodation space 674, the electromechanical conversion element 69 is accommodated such that the expansion / contraction direction thereof coincides with the axial direction of the support member 67. Further, the drive member 71 is accommodated in the second accommodation space 675 so as to be movable in the axial direction.
[0065]
  The electromechanical conversion element 69 is configured in the same manner as the electromechanical conversion element 26 shown in FIG. 2, and one end face (for example, the positive electrode side) that is the expansion / contraction direction (stacking direction) is the first accommodation space 674. Is fixed to the end surface on the one end 671 side. The drive member 71 is composed of a shaft body in which a bulging portion 711 bulging on both the left and right sides of the support member 67 is integrally formed at the center portion, and the bulging portion 711 is located in the second accommodation space 675. The end protruding into the first accommodation space 674 through the through hole formed in the partition wall 673 is fixed to the other end surface (for example, the negative electrode side) of the electromechanical conversion element 69, and the other end of the support member 67. An end protruding outside the second accommodation space 675 through a through hole formed in the portion 672 is a free end.
[0066]
  The moving body 65 has a flat plate portion 651 and side wall portions 652 and 653 extending downward on the left and right sides of the flat plate portion 651 and sliding members 654 and 655 formed inside the side wall portions 652 and 653. Therefore, the moving member 42 is fixed to the upper surface of the support member 67 by a screw member 656.
[0067]
  The moving member 42 configured in this manner is assembled to the engaging member 40 by the bulging portion 711 of the driving member 71 being movably held between the pair of holding members 50 and 52 of the engaging member 40. become. That is, the engagement member 40 corresponds to the engagement member 30 of FIG. 2, and this engagement member 40 is coupled to the drive member 71 with a predetermined frictional force, so that the drive units 12 ′ and 14 ′ are configured. Will be.
[0068]
  In the drive units 12 ′ and 14 ′, when the drive voltage having the waveform shown in FIG. 4A, for example, is applied from the drive circuit unit 16 to the electromechanical conversion element 69 and the electromechanical conversion element 69 is gently expanded, the drive is performed. When the support member 67 moves to one side of the engagement member 40 in a state where the member 71 is stationary, and then the electromechanical conversion element 69 is rapidly reduced, the drive member 71 is held in the state where the support member 67 is stationary. It moves to one side of the engaging member 40 by overcoming the frictional force of 50 and 52. By this repetitive operation, the support member 67 moves intermittently to one side of the engagement member 40 together with the moving body 65.
[0069]
  Further, when the drive voltage having the waveform shown in FIG. 4B, for example, is applied from the drive circuit unit 16 to the electromechanical conversion element 69 and the electromechanical conversion element 69 is rapidly expanded, the support member 67 is driven in a stationary state. When the member 71 overcomes the frictional force generated by the holding members 50 and 52 and moves to the other side of the engaging member 40, and then the electromechanical conversion element 69 is gradually reduced, the support member 67 remains in a state where the driving member 71 is stationary. It moves to the other side of the engaging member 40. The support member 67 moves intermittently to the other side of the engaging member 40 together with the moving body 65 by this repeated operation.
[0070]
  As described above, the drive device according to the embodiment of the present invention includes the first switch unit 162 that drives the electromechanical transducers 26 and 69 of the first drive units 12 and 12 ′, and the second drive unit 14. , 14 ′ and a second switch unit 163 that drives the electromechanical conversion elements 26 and 69 and a part of the circuit shares a part of the circuit of the first switch unit 162. ing. For this reason, since the number of parts for configuring the drive circuit unit is reduced, a drive device that can promote downsizing of the system even when two drive objects are individually driven in the same system is realized. Can do. Further, since the number of parts for configuring the drive circuit unit is reduced, the cost of the drive device can be reduced.
[0071]
  In addition, this invention is not limited to the thing of the said embodiment, A various deformation | transformation aspect is employable as needed. For example, in the case of the drive circuit unit 16 shown in FIG. 3, the second, fourth, and sixth of the first and second switch units 162 and 163.ofA circuit configuration in which resistance elements having predetermined resistance values are respectively connected between the switching elements Q2, Q4, Q6 and the ground can be employed. Further, although the MOSFET is used as the switching element, the present invention is not limited to this. For example, a bipolar transistor can be used.
[0072]
  In the above-described embodiment, the drive control signal output from the control signal output unit 164 is supplied to the third switch circuit 167 that is a circuit shared by the first switch unit 162 and the second switch unit 163. The drive control signal Sc3 and the drive control signal Sc4 supplied to the fourth switch circuit 168 are opposite in phase with each other and the duty ratio is set to 0.5. However, the present invention is not limited to this. For example, the duty ratio can be changed within a range in which the first and second drive units 12 and 14 (or 12 'and 14') can be driven in both the feeding direction and the return direction. Further, the duty ratio can be set to a different value depending on the driving direction of the first and second driving units 12, 14 (or 12 ', 14') and the return driving direction.
[0073]
  Moreover, in the said embodiment, although the drive voltage which consists of a rectangular wave is applied to each electromechanical conversion element, it is not restricted to this. For example, a series circuit of a resistance element and a switching element is connected in parallel to each of the second switch circuit 166, the fourth switch circuit 168, and the sixth switch circuit 170, and any one of the switch circuit and the series circuit is connected. A sawtooth drive voltage may be applied to each electromechanical conversion element by selectively driving. In this case, the engaging member 30 can be moved relative to the support member 24 in the feeding direction by slowing the rising portion of the sawtooth drive voltage and making the falling portion steep, and the rising portion The engagement member 30 can be moved relative to the support member 24 in the return direction by making the falling part slow and steep.
[0074]
【The invention's effect】
  As explained above, according to the present invention,A part of the circuit of the first switch unit for driving the first electromechanical transducer and a part of the circuit of the second switch unit for driving the second electromechanical transducer are shared with each other The drive control means can cause the switching element shared by the first switch unit and the second switch unit to drive the first drive unit and the second drive unit simultaneously. Give drive control signal of duty ratioTherefore, it is possible to realize a driving device that can promote downsizing of the system even when two driving objects are individually driven in the same system.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing an overall configuration of a driving apparatus according to an embodiment of the present invention.
FIG. 2 is a perspective view showing a configuration example of a drive unit of the drive device shown in FIG. 1;
3 is a block diagram showing a configuration example of a drive circuit unit of the drive device shown in FIG. 1. FIG.
FIGS. 4A and 4B are diagrams showing waveforms of drive pulses formed by the drive circuit section shown in FIG. 3, wherein FIG. 4A shows a duty ratio set to be 0.3, and FIG. 4B shows a duty ratio. It is set to be 0.7.
5 is a diagram showing the relationship between fd / fr and the moving speed of the engaging member in the driving apparatus shown in FIG.
6 is a diagram showing a relationship between a duty ratio of a driving voltage and a moving speed of an engaging member in the driving apparatus shown in FIG.
7 is a diagram showing a relationship between a drive voltage applied to the electromechanical transducer of the drive device shown in FIG. 1 and a displacement waveform due to expansion and contraction of the electromechanical transducer, and (a) shows the duty ratio of the drive voltage. FIG. 6B shows a case where the duty ratio is set to be 0.3, and FIG. 5B shows a case where the duty ratio of the drive voltage is set to be 0.7.
FIG. 8 is a diagram illustrating a drive voltage composed of a rectangular wave applied to an electromechanical transducer.
9 is a diagram showing a fundamental wave and a harmonic component obtained by performing Fourier transform on the drive voltage shown in FIG.
FIG. 10 is a diagram showing the resonance characteristics of the electromechanical transducer in a state where the support member and the drive member are fixed.
11 is a diagram showing a fundamental wave and a harmonic component when the drive voltage shown in FIG. 8 is applied to the electromechanical transducer having the resonance characteristics shown in FIG.
12 is a diagram showing a displacement waveform of an electromechanical transducer obtained by inverse Fourier transform of the fundamental wave and the harmonic component shown in FIG.
FIG. 13 is a diagram showing a relationship between a drive voltage having a drive frequency outside the range of the present invention and a displacement waveform due to expansion and contraction of the electromechanical transducer, and (a) shows that the duty ratio of the drive voltage is 0.3. (B) is set so that the duty ratio of the drive voltage is 0.7.
14 is a timing chart for explaining the operation of the drive circuit section shown in FIG. 3;
FIGS. 15A and 15B are diagrams showing another configuration example of a drive unit in the drive device shown in FIG. 1, wherein FIG. 15A is an exploded perspective view thereof, and FIG. 15B is a front view thereof;
FIG. 16 is a diagram schematically showing a configuration of a conventional driving device.
[Explanation of symbols]
10 Drive device
12, 12 'first drive unit
14, 14 'second drive unit
16 Drive circuit section
18 Control unit (drive control means)
24, 67 support member
26, 69 electromechanical transducer
28, 71 Drive member
30, 40 engagement member
161 Drive power supply
162 First switch part
163 Second switch section
164 Control signal output unit
165 First switch circuit
166 Second switch circuit
167 Third switch circuit
168 Fourth switch circuit
169 Fifth switch circuit
170 Sixth switch circuit
Q1 first switching element
Q2 Second switching element
Q3 Third switching element
Q4 Fourth switching element
Q5 Fifth switching element
Q6 Sixth switching element

Claims (1)

A first electromechanical transducer having a counter electrode, a first support member secured to one electrode side of the first electromechanical transducer, and secured to the other electrode side of the first electromechanical transducer A first drive member comprising a first drive member made and a first engagement member engaged with the first drive member with a predetermined frictional force;
A second electromechanical conversion element having a counter electrode, a second support member fixed to one electrode side of the second electromechanical conversion element, and fixed to the other electrode side of the second electromechanical conversion element A second drive member comprising a second drive member and a second engagement member engaged with the second drive member with a predetermined frictional force;
A driving power source for outputting a DC voltage, a first switch unit including a plurality of switching elements connected between the driving power source and the ground, and a switch including a plurality of switching elements connected between the driving power source and the ground the second switch unit portion of the switching element a part is that are shared with part of the switching elements of the first switch section, and the first switch unit from the driving power source by controlling driving The output DC voltage is applied to the first electromechanical conversion element as a first drive voltage of a rectangular wave, and the DC voltage output from the drive power supply by driving the second switch unit. A drive circuit unit comprising a control signal output unit configured to apply the second electromechanical conversion element to the second electromechanical transducer as a rectangular wave second drive voltage;
The first electromechanical conversion element is expanded and contracted at different speeds in the extending direction and the reducing direction by changing the duty ratio of the first driving voltage by driving and controlling the control signal output unit. The support member and the first engagement member are moved relative to each other, and the duty ratio of the second drive voltage is changed to move the second electromechanical transducer at different speeds in the extension direction and the reduction direction. Drive control means for relatively moving the second support member and the second engagement member by extending and contracting ;
The drive control means controls the drive of the control signal output unit and supplies a drive control signal having a predetermined duty ratio supplied from the control signal output unit to each switching element included in the first switch unit and the second switch unit. The switching element shared by the first switch unit and the second switch unit can simultaneously drive the first drive unit and the second drive unit. A drive device characterized by providing a drive control signal with a proper duty ratio .

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