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JP2004248399A - Vibrator and ultrasonic motor - Google Patents

Vibrator and ultrasonic motor Download PDF

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Publication number
JP2004248399A
JP2004248399A JP2003035177A JP2003035177A JP2004248399A JP 2004248399 A JP2004248399 A JP 2004248399A JP 2003035177 A JP2003035177 A JP 2003035177A JP 2003035177 A JP2003035177 A JP 2003035177A JP 2004248399 A JP2004248399 A JP 2004248399A
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Prior art keywords
vibrator
vibration
bending vibration
longitudinal
piezoelectric ceramic
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Inventor
Yoshiro Tomikawa
義朗 富川
Mutsuo Munekata
睦夫 宗片
Atsushi Furuta
淳 古田
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NANO CONTROL KK
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NANO CONTROL KK
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibrator which has large generation capacity, and an ultrasonic motor which has large driving force, equipped with this vibrator. <P>SOLUTION: The vibrator 1 has a vertical vibration part, where a piezoelectric element 4a is arranged on the ZX face of a structure 3a, a flexural vibration part 2b where piezoelectric elements 4b and 4c are arranged on the XY face of the structure 3b, shoe members 6a and 6b, a retention member 7 for holding the flexural vibration part 2b, a pushing means 8 which pushes the shoe members 6a and 6b against a body 80 to be shifted, and a fixing means 9 which fixes the pushing means 8. It shifts the body 80 to be shifted, by applying a specified drive voltage to piezoelectric elements 4a-4c, thereby extending and contracting the vertical vibrating part 2a to vibrate in the X direction and also by flexurally vibrating the flexural vibration part 2b in the Z direction, and thereby generating elliptic travelling waves in the shoe members 6a and 6b. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は圧電素子を駆動させることによって所定の振動モードで振動する振動子と、この振動子を備えた超音波モータに関する。
【０００２】
【従来の技術】
圧電振動子の楕円進行波を利用した超音波モータとして、特開平７−１８４３８２号公報（特許文献１）には、図１９に示すように、圧電材料からなる矩形の圧電板２０１と、圧電板２０１の短辺の側面中央部に設けられ、被移動体２１０と接する接頭部材２０２と、圧電板２０１の一方の長辺を剛性的に保持する第１保持部材２０３と、圧電板２０１の他方の短辺と長辺とを弾性的に保持する第２保持部材２０４と、を有する超音波モータ２００が開示されている。
【０００３】
圧電板２０１の表面に４つの分割電極２０５ａ〜２０５ｄが形成されており、分割電極２０５ａ・２０５ｄどうしが電気的に接続され、分割電極２０５ｂ・２０５ｃどうしが電気的に接続されている。また圧電板２０１の裏面にはほぼ全面に接地電極（図示せず）が形成されている。分割電極２０５ａ・２０５ｄと分割電極２０５ｂ・２０５ｃにそれぞれ符号の反転した単極非対称パルス電圧を印加することによって、接頭部材２０２の先端に縦振動モードと屈曲振動モードとが合成された楕円進行波を生じさせることができる。接頭部材２０２と接している被移動体２１０は、接頭部材２０２の楕円進行波の方向に応じて、図１９中の＋Ｘ方向または−Ｘ方向に移動する。
【０００４】
【特許文献１】
特開平７−１８４３８２号公報（第５、６頁、第１図）
【０００５】
【発明が解決しようとする課題】
このような超音波モータ２００の屈曲振動モードと縦振動モードの入力アドミッタンス特性は図２０に示す通りであり、超音波モータ２００においては、屈曲振動モードのアドミッタンスが縦振動モードのアドミッタンスよりも小さくなっていることがわかる。このことは、超音波モータ２００では、屈曲振動モードの振幅が縦振動モードの振幅に比べて小さいために、大きな駆動力が得られ難いことを示している。
【０００６】
本発明はこのような事情に鑑みてなされたものであり、駆動力の大きい振動子およびこの振動子を備えた超音波モータ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】
本発明の第１の観点によれば、略矩形の形状を有し、その長手方向に伸縮振動する縦振動部と、
前記縦振動部と略同一長さの略矩形形状を有し、その厚み方向に屈曲振動する屈曲振動部と、
を具備する振動子であって、
前記縦振動部の伸縮振動方向と前記屈曲振動部の屈曲振動方向が直交し、かつ、前記縦振動部の長手方向と前記屈曲振動部の長手方向が一致し、
前記屈曲振動方向と前記伸縮振動方向とに直交する方向における、屈曲振動部の長さが前記縦振動部の長さよりも長いことを特徴とする振動子、が提供される。
【０００８】
このような振動子では、縦振動部と屈曲振動部とは、断面略Ｌ字型または断面略Ｔ字型に接続される。
【０００９】
本発明の第２の観点によれば、略矩形の形状を有し、所定間隔でその主面が平行となるように配置され、その長手方向に伸縮振動する複数の縦振動部と、
前記縦振動部の長さと略同一の長さの略矩形形状を有し、その厚み方向に屈曲振動する屈曲振動部と、
を具備する振動子であって、
前記縦振動部の伸縮振動方向と前記屈曲振動部の屈曲振動方向が直交し、かつ、前記縦振動部の長手方向と前記屈曲振動部の長手方向が一致し、
前記屈曲振動方向と前記伸縮振動方向とに直交する方向における、前記屈曲振動部の長さが前記複数の縦振動部の長さの合計長さよりも長いことを特徴とする振動子、が提供される。
【００１０】
これら第１および第２の観点に係る振動子においては、縦振動部として第１の矩形構造体の主面の一方または両方に第１の板状圧電素子が配設されたものを用い、同様に、屈曲振動部として第２の矩形構造体の表面に第２の板状圧電素子が配設されたものを用いることができる。ここで、第１の矩形構造体と第２の矩形構造体は一体的に構成されていることが好ましい。或いは、縦振動部として主面に電極が形成された略矩形の第１の圧電セラミック板を用い、屈曲振動部として主面に電極が形成された略矩形の第２の圧電セラミック板を用いることも好ましい。この第１の圧電セラミック板と前記第２の圧電セラミック板は一体的に構成されていることが好ましい。
【００１１】
第１および第２の観点に係る振動子においては、縦振動部と屈曲振動部をそれぞれ複数の圧電セラミック薄板と電極とが交互に積層された構造としてもよい。これにより駆動電圧を下げることができる。縦振動部における積層方向と屈曲振動部における積層方向は共に、屈曲振動部の屈曲振動方向に一致させてもよいし、屈曲振動部の長手方向に一致させてもよい。
【００１２】
本発明の第３の観点によれば、略矩形形状を有し、その長手方向に実質的に同一形状を有する第１の駆動部および第２の駆動部を少なくとも並べ備えた第１の構造体と、
前記第１の構造体と略同一長さを有し、その厚みが前記第１の構造体の幅よりも短く、その長手方向に実質的に同一形状を有する第３の駆動部および第４の駆動部を少なくとも並べ備えた第２の構造体と、
を具備する振動子であって、
前記第１の駆動部と前記第４の駆動部とが対角に位置するように、前記第１の構造体の主面に前記第２の構造体の幅方向の側面が接続され、
前記第１の駆動部と前記第４の駆動部を同位相で伸縮させ、前記第２の駆動部と前記第３の駆動部を同位相かつ前記第１の駆動部と略９０度ずれた位相で伸縮させることにより、前記第１位の構造体と前記第２の構造体の所定位置に楕円進行波が生ずることを特徴とする振動子、が提供される。
【００１３】
本発明の第４の観点によれば、略矩形の形状を有し、その長手方向に伸縮振動する縦振動部と、
前記縦振動部と略同一長さの略矩形形状を有し、その厚み方向に屈曲振動する屈曲振動部と、
を具備し、
前記縦振動部の伸縮振動方向と前記屈曲振動部の屈曲振動方向が直交し、かつ、前記縦振動部の長手方向と前記屈曲振動部の長手方向が一致している振動子であって、
前記屈曲振動部の入力アドミッタンスが、前記縦振動部の入力アドミッタンスの６０％以上であることを特徴とする振動子、が提供される。
このような入力アドミッタンス特性を有する振動子では、屈曲振動モードによる発生力が大きくなるために、駆動力を高めることができる。
【００１４】
本発明の第５の観点によれば、円筒形の圧電セラミック部材と、
前記圧電セラミック部材の内周面に設けられ、接地電極として用いられる共通電極と、
超音波領域の交番電圧が印加されることによって前記圧電セラミック部材の端面の略中心部に楕円進行波が生ずるように、前記圧電セラミック部材の外周面に所定パターンで設けられた駆動電極と、
を具備することを特徴する振動子、が提供される。
【００１５】
この第５の観点に係る振動子における駆動電極の一形態として、圧電セラミック部材の周回りで略２等分割され、かつ、長手方向で略２等分割されて形成される４個の電極要素が、２組の電極群が形成されるようにたすき掛けして接続された形態を挙げることができる。また、駆動電極の別の形態としては、圧電セラミック部材の周回りで略４等分割され、かつ、圧電セラミック部材の径方向で対向する２組の電極のうち１組の電極は圧電セラミック部材の長手方向で略２等分割されて形成される６個の電極要素を有する形態が挙げられ、この場合には、圧電セラミック部材の長手方向で略２等分割されてなる４個の電極要素をたすき掛けして接続することによって２組の電極群を構成し、圧電セラミック部材の長手方向で分割されていない２個の電極要素を互いに接続されることによって１組の電極群を構成する。
【００１６】
本発明の第６の観点によれば、平板リング状の圧電セラミックリングと電極とが交互に積層された円筒状構造体と、前記円筒状構造体の端面に配設された円板部材と、を有する振動子であって、
前記電極は、
前記圧電セラミックリングの円周回りに所定数に略等分割された駆動電極と、
前記圧電セラミックリングの主面と略同形状のリング状の接地電極と、
を有し、
前記駆動電極は、複数の電極群が構成されるように電気的に接続され、
前記複数の電極群に超音波領域の交番電圧が印加されることによって、前記円板部材の端面の略中心部に楕円進行波が生ずることを特徴とする振動子、が提供される。
【００１７】
この第６の観点に係る振動子において、駆動電極の形態としては、径方向で略２等分割された略半円弧状の形状を有する形態や、径方向で略４等分割された略１／４円弧状の形状を有する形態が挙げられる。圧電セラミックリングと電極との積層方向中央部には、接地電極に挟まれた圧電不活性な圧電セラミックリングを設けることが好ましい。このような第５および第６の観点に係る振動子では、圧電セラミックス管や円筒構造体の長手方向での発生力が大きくなるために、大きな駆動力が得られる。
【００１８】
本発明によれば、上述した振動子を備えた超音波モータが提供される。
すなわち、本発明の第７の観点によれば、略矩形の形状を有し、その長手方向に伸縮振動する縦振動部と、前記縦振動部と略同一長さの略矩形形状を有し、その厚み方向に屈曲振動する屈曲振動部とを具備し、前記縦振動部の伸縮振動方向と前記屈曲振動部の屈曲振動方向が直交し、かつ、前記縦振動部の長手方向と前記屈曲振動部の長手方向が一致している振動子と、
前記屈曲振動部の屈曲振動に起因して前記縦振動部に生ずる前記屈曲振動方向の振動の腹部の近傍に配設された接頭部材と、
前記屈曲振動部において前記屈曲振動部に生ずる屈曲振動の節部の近傍に配設された保持部材と、
前記保持部材を保持する保持手段と、
前記接頭部材が被移動体に所定の力で押し当てられるように前記保持手段を前記被移動体に押圧する押圧手段と、
を備え、
前記振動子において、前記屈曲振動方向と前記伸縮振動方向とに直交する方向における、屈曲振動部の長さが前記縦振動部の長さよりも長く、
前記縦振動部の伸縮振動と前記屈曲振動部の屈曲振動とが合わされて前記接頭部材に楕円運動が生ずることによって、前記被移動体を所定の方向に移動させることを特徴とする超音波モータ、が提供される。
【００１９】
本発明の第８の観点によれば、略矩形の形状を有し、所定間隔でその主面が平行となるように配置され、その長手方向に伸縮振動する複数の縦振動部と、前記縦振動部の長さと略同一の長さの略矩形形状を有し、その厚み方向に屈曲振動する屈曲振動部とを具備し、前記縦振動部の伸縮振動方向と前記屈曲振動部の屈曲振動方向とが直交し、かつ、前記縦振動部の長手方向と前記屈曲振動部の長手方向とが一致している振動子と、
前記屈曲振動部の屈曲振動に起因して前記縦振動部に生ずる前記屈曲振動方向の振動の腹部の近傍に配設された接頭部材と、
前記屈曲振動部において前記屈曲振動部に生ずる屈曲振動の節部の近傍に配設された保持部材と、
前記保持部材を保持する保持手段と、
前記接頭部材が被移動体に所定の力で押し当てられるように前記保持手段を前記被移動体に押圧する押圧手段と、
を備え、
前記振動子において、前記屈曲振動方向と前記伸縮振動方向とに直交する方向における、前記屈曲振動部の長さが前記複数の縦振動部の長さの合計長さよりも長く、
前記縦振動部の伸縮振動と前記屈曲振動部の屈曲振動とが合わされて前記接頭部材に楕円運動が生ずることによって、前記被移動体を所定の方向に移動させることを特徴とする超音波モータ、が提供される。
【００２０】
本発明の第９の観点によれば、略矩形形状を有し、その長手方向に実質的に同一形状を有する第１の駆動部および第２の駆動部を少なくとも並べ備えた第１の構造体と、前記第１の構造体と略同一長さを有し、その厚みが前記第１の構造体の幅よりも短く、その長手方向に実質的に同一形状を有する第３の駆動部および第４の駆動部を少なくとも並べ備えた第２の構造体とを具備し、前記第１の駆動部と前記第４の駆動部とが対角に位置し、かつ、前記第１の構造体の主面に前記第２の構造体の幅方向の側面が合わせされてなる振動子と、
前記振動子において、前記第１の駆動部と前記第４の駆動部を同位相で伸縮させ、前記第２の駆動部と前記第３の駆動部を同位相かつ前記第１の駆動部と略９０度ずれた位相で伸縮させることによって生ずる振動の腹の部分の近傍に配設された接頭部材および前記振動の節の部分の近傍に配置された保持部材と、
前記保持部材を保持する保持手段と、
前記接頭部材が被移動体に所定の力で押し当てられるように前記保持手段を前記被移動体に押圧する押圧手段と、
を備えていることを特徴とする超音波モータ、が提供される。
【００２１】
本発明の第１０の観点によれば、円筒形の圧電セラミック部材と、
前記圧電セラミック部材の内周面に設けられ、接地電極として用いられる共通電極と、
超音波領域の交番電圧が印加されることによって前記圧電セラミック部材の端面の略中心部に楕円進行波が生ずるように、前記圧電セラミック部材の外周面に所定のパターンで設けられた駆動電極と、
前記圧電セラミック部材の端面を閉塞する蓋体と、
前記蓋体の略中心部に配設された接頭部材と、
前記圧電セラミック部材を保持する保持手段と、
前記接頭部材が被移動体に所定の力で押し当てられるように前記保持手段を前記被移動体に押圧する押圧手段と、
を具備することを特徴する超音波モータ、が提供される。
【００２２】
本発明の第１１の観点によれば、平板リング状の圧電セラミックリングと薄膜状の電極とが交互に積層された円筒状構造体と、
前記円筒状構造体の端面を閉塞する蓋体と、
前記蓋体の略中心部に配設された接頭部材と、
前記円筒状構造体を保持する保持手段と、
前記接頭部材が被移動体に所定の力で押し当てられるように前記保持手段を前記被移動体に押圧する押圧手段と、
を具備し、
前記電極は、
前記圧電セラミックリングの円周回りで所定数に略等分割された駆動電極と、
前記圧電セラミックリングの主面と略同形状のリング状の接地電極と、
を有し、
前記駆動電極は、複数の電極群が構成されるように電気的に接続され、
前記複数の電極群に超音波領域の交番電圧が印加されることによって前記接頭部材に楕円進行波が生ずることを特徴とする超音波モータ、が提供される。
【００２３】
このような超音波モータは駆動力が大きいために、重量物を容易に移動させることができる。
【００２４】
【発明の実施の形態】
以下、本発明の実施の形態について図面を参照しながら詳細に説明する。図１は本発明の実施形態である振動子１の概略構造を示す斜視図であり、図２は振動子１を用いた超音波モータ１００の構成を示す側面図（図２（ａ））および断面図（図２（ｂ））である。
【００２５】
振動子１は略矩形の形状を有し、その長手方向（Ｘ方向）に伸縮振動する縦振動部２ａと、縦振動部２ａの長さと同一の長さの略矩形形状を有し、厚み方向（Ｚ方向）に屈曲振動する屈曲振動部２ｂと、縦振動部２ａのＸＹ面（Ｚ方向軸に垂直な面（Ｘ方向とＺ方向の両方向と直交する方向をＹ方向とする））に設けられ、被移動体８０に接する接頭部材６ａ・６ｂと、屈曲振動部２ｂを保持するために屈曲振動部２ｂのＸＹ面に設けられた保持部材７と、保持部材７を保持して接頭部材６ａ・６ｂを被移動体８０に押圧する押圧手段８と、押圧手段８を固定する固定手段９と、を有してる。また、超音波モータ１００は、振動子１と、被移動体８０と、被移動体８０をＸ方向に移動可能な状態で保持する図示しないガイドレールと、を有している。
【００２６】
なお、図１においては押圧手段８と固定手段９の図示を省略しており、以下に説明する振動子１以外の他の振動子についても、それらを図示する際の押圧手段８と固定手段９の図示を省略する。
【００２７】
縦振動部２ａは、矩形の構造体３ａのＺＸ面（Ｙ方向軸に垂直な面）の一方に板状の圧電素子４ａが配設された構造を有している。例えば、圧電素子４ａは接着剤を用いて構造体３ａに接着することができる。また、屈曲振動部２ｂは、矩形の構造体３ｂのＸＹ面に、実質的に同じ形状を有する２枚の板状の圧電素子４ｂ・４ｃがＸ方向に並べて所定の狭い間隔をあけて配設された構造を有している。これら縦振動部２ａと屈曲振動部２ｂとが実質的に振動子を構成し、接頭部材６ａ・６ｂは、後述するように、縦振動部２ａと屈曲振動部２ｂに生ずる振動を効率よく被移動体８０に伝える部材である。
【００２８】
構造体３ａ・３ｂは、アルミニウム、ステンレス等の金属材料からなる。図１および図２においては、構造体３ａと構造体３ｂとは断面略Ｌ字型の一体構造を有する形態を示しているが、構造体３ａと構造体３ｂは、接着剤によって接着され、または溶接によって接合されていてもよい。なお、後述するように構造体３ａ・３ｂとして絶縁体を用いることもできる。
【００２９】
圧電素子４ａ〜４ｃはそれぞれ、圧電セラミック板の表裏面に電極が設けられた構造を有している。なお、図１では圧電セラミック板と電極とを分けて図示していない。圧電素子４ａの圧電セラミック板の分極の向きは＋Ｙの向きとなっている（矢印Ｐ１）。また、圧電素子４ｂの圧電セラミック板の分極の向きは＋Ｚの向きとなっている（矢印Ｐ２）が、圧電素子４ｃの圧電セラミック板の分極の向きは−Ｚの向きとなっている（矢印Ｐ３）。また、圧電素子４ｂと圧電素子４ｃの表面電極は電気的に接続されている。
【００３０】
圧電素子４ａの裏面電極は構造体３ａと導通し、圧電素子４ｂ・４ｃの裏面電極は構造体３ｂと導通している。構造体３ａ・３ｂは一体的に金属材料で構成されているために、結果的に、構造体３ａ・３ｂを圧電素子４ａ〜４ｃを駆動する際の共通電極（アース電極）として用いることができる。
【００３１】
例えば、圧電素子４ａの表面電極に電圧Ｖ＝Ｖ０ｃｏｓωｔ（Ｖ０：定格電圧、ω：周波数、ｔ：時間）の交流電圧を印加すると、縦振動部２ａには圧電素子４ａのｄ３１モードの圧電効果によってＸ方向に伸縮振動が発生する（縦振動モード）。また、圧電素子４ｂ・４ｃの表面電極に、圧電素子４ａの表面電極に印加する電圧とは９０度位相がずれている電圧Ｖ＝Ｖ０ｓｉｎωｔの交流電圧を印加すると、圧電素子４ｂ・４ｃそれぞれの圧電セラミック板の分極の向きが逆になっているために、屈曲振動部２ｂには圧電素子４ｂ・４ｃのｄ３１モードの圧電効果と構造体３ｂのクランプ効果によって、Ｚ方向での屈曲振動が発生する（屈曲２次振動モード）。
【００３２】
縦振動部２ａの伸縮振動方向と屈曲振動部２ｂの屈曲振動方向とを直交させることによって、これら伸縮振動と屈曲振動とが合成されて接頭部材６ａ・６ｂに楕円進行波が生ずる。接頭部材６ａ・６ｂは押圧手段８によって所定の力で被移動体８０に押しつけられているために、被移動体８０は接頭部材６ａ・６ｂから受ける力によって−Ｘの向きまたは＋Ｘの向きに移動する。なお、接頭部材６ａ・６ｂに生ずる楕円進行波の向きは、圧電素子４ａに印加する電圧と圧電素子４ｂ・４ｃに印加する電圧の位相差によって変えることができる。
【００３３】
なお、屈曲振動部２ｂにおける屈曲振動は、構造体３ｂのＸ方向の中央部を節とし、圧電素子４ｂ・４ｃのそれぞれのＸ方向の中央部を腹とする。そこで、図１および図２に示されるように、接頭部材６ａ・６ｂは、屈曲振動部２ｂの屈曲振動の腹の位置に対応する位置の近傍に設けられる。これにより接頭部材６ａ・６ｂのＺ方向の変位量を大きく取ることができる。また、保持部材７を屈曲振動部２ｂの屈曲振動の節の近傍部分、つまりＸ方向の中央部近傍に設けることが好ましい。これによって、押圧手段８と保持部材７とが振動によって外れることが抑制され、振動子１を安定して保持することができる。
【００３４】
接頭部材６ａ・６ｂとしては、超硬合金材料や鋳鉄等の硬質材料からなるものや、アルミナやジルコニア、炭化珪素、窒化珪素等の耐摩耗性セラミック材料からなるもの、これらの材料からなるものに酸化チタンまたはダイヤモンドをコーティングしたもの、が好適に用いられる。接頭部材６ａ・６ｂは、構造体３ａと一体構造を有していてもよい。接頭部材６ａ・６ｂの先端を円形または球形等にすることにより、摩耗を低減することができる。被移動体８０としては、レイデント処理等の硬質処理が施されたものが好適に用いられる。
【００３５】
保持部材７としては、例えば、円柱形状やボルト形状を有する金属部材等を用いることができる。また、押圧手段８としては、接頭部材６ａ・６ｂが被移動体８０に所望の力で押圧されるように、バネ機構等の弾性機構が用いられる。押圧手段８は、保持部材７の形状と材質に応じて、例えば、溶接により、またはボルト締め等の機械的連結によって保持部材７に取り付けられる。なお、押圧手段８としては、エアーシリンダ等を用いることもできる。
【００３６】
振動子１では、屈曲振動部２ｂのＹ方向長さ（Ｄ２）が縦振動部２ａのＹ方向長さ（Ｄ１）よりも充分大きいために、図３に示すように、屈曲振動モードの入力アドミッタンスの値が大きくなる。例えば、図１９に示した超音波モータ２００では、屈曲振動の入力アドミッタンス値を縦振動の入力アドミッタンス値で除して得られる比率は約０．３であるが、超音波モータ１００ではこの比率を１．０とすることができる。つまり、超音波モータ１００では、屈曲振動による発生力が大きくなるために、被移動体８０が重量物であってもこれを移動させることができる。駆動力の大きな超音波モータを実現するためには、屈曲振動モードの入力アドミッタンスの値が縦振動モードの入力アドミッタンスの値の６０％以上となるように、振動子１を構成する各部の寸法等を設計することが好ましい。
【００３７】
上述した振動子１では、例えば、圧電素子４ｃを構成する圧電セラミック板の分極の向きを圧電素子４ｂと同じように矢印Ｐ２で示される＋Ｚの向きとし、かつ、圧電素子４ｂの表面電極と圧電素子４ｃの表面電極とを電気的に接続しない構造とすることもできる。この場合には、例えば、圧電素子４ａの表面電極に電圧Ｖ＝Ｖ０ｃｏｓωｔの交流電圧を印加すると同時に、圧電素子４ｂの表面電極に電圧Ｖ＝Ｖ０ｓｉｎωｔの交流電圧を印加し、かつ、圧電素子４ｃの表面電極には圧電素子４ｂの表面電極に印加する電圧と位相が１８０度ずれた電圧、つまり電圧Ｖ＝−Ｖ０ｓｉｎωｔの交流電圧を印加すればよい。
【００３８】
また、振動子１に用いられている構造体３ａ・３ｂとしては、絶縁材料（例えば、アルミナやジルコニア、窒化珪素等のエンジニアリングセラミックス）を用いることができる。この場合には、構造体３ａ・３ｂ自体をアース電極として用いることができないので、圧電素子４ａ〜４ｃの裏面電極を構造体３ａ・３ｂのＹＺ面（Ｘ方向軸に垂直な面）から取り出せばよい。例えば、構造体３ａにおいて圧電素子４ａが配設される面と構造体３ａのＹＺ面に電気的に接続された電極を設けておけば、圧電素子４ａのアース電極の取り出しを構造体３ａのＹＺ面から容易に行うことができる。構造体３ｂについても同様の構造とすることができる。
【００３９】
振動子１は、図４の斜視図に示す振動子１Ａのように変形させることができる。図４に示す振動子１Ａと図１に示した振動子１との相違点は、屈曲振動部の構成と接頭部材の配設位置および配設数である。具体的には、振動子１Ａは、圧電素子４ａを備えた縦振動部２ａと、構造体３ｂの表面に３枚の実質的に同一形状を有する圧電素子４ｄ・４ｅ・４ｆが所定の狭い間隔をあけてＸ方向に並べて配設された屈曲振動部２ｂ´と、を有している。
【００４０】
屈曲振動部２ｂ´においては、圧電素子４ｄ・４ｆを構成する圧電セラミック板の分極の向きは＋Ｚの向きであり（矢印Ｐ２）、圧電素子４ｅを構成する圧電セラミック板の分極の向きは−Ｚの向きであり（矢印Ｐ３）、圧電素子４ｄ〜４ｆの表面電極は互いに電気的に接続されている。
【００４１】
金属材料からなる構造体３ａ・３ｂを接地電極として用い、圧電素子４ｄ〜４ｆの表面電極に電圧Ｖ＝Ｖ０ｓｉｎωｔの交流電圧を印加すると、圧電素子４ｄ〜４ｆそれぞれのＸ方向中央部が腹となり、圧電素子４ｄと圧電素子４ｅの境界部および圧電素子４ｅと圧電素子４ｆの境界部をそれぞれ節とする屈曲振動が生ずる。このため、被移動体（図示せず）に接する接頭部材６ｄ〜６ｆは、縦振動部２ａにおいてこの屈曲振動の腹に対応する位置に配設されている。また、屈曲振動部２ｂ´において、この屈曲振動の節となる圧電素子４ｄと圧電素子４ｅ間に保持部材７ａが、圧電素子４ｅと圧電素子４ｆの間の位置に保持部材７ｂが、それぞれ配設されている。
【００４２】
圧電素子４ｄ〜４ｆへの電圧Ｖ＝Ｖ０ｓｉｎωｔの印加と同時に、圧電素子４ａの表面電極に電圧Ｖ＝Ｖ０ｃｏｓωｔの交流電圧を印加すると、接頭部材６ｄ・６ｆには同じ位相の楕円進行波が生じ、接頭部材６ｅには接頭部材６ｄ・６ｆと１８０度ずれた楕円進行波が生ずる。これにより、振動子１Ａは振動子１と同様に被移動体（図示せず）をＸ方向に移動させることができる。
【００４３】
なお、屈曲振動部２ｂ´が具備する圧電素子の数は４個以上であってもよい。構造体３ｂに配設される圧電素子の数に応じて、接頭部材を縦振動部２ａにおいて各圧電素子のＸ方向中央部に対応する位置に配置し、保持部材を各圧電素子の間に配置すればよい。各圧電素子の表面電極をワイヤで接続する場合には、各圧電素子を構成する圧電セラミック板の分極の向きが互い違いとなるように各圧電素子を配置する。
【００４４】
次に本発明の別の実施形態について説明する。図５は振動子１０の概略構造を示す斜視図である。この振動子１０は、図１に示した振動子１を構成する構造体３ａ・３ｂとして、圧電セラミック板を用いた形態の一例である。
【００４５】
振動子１０は、矢印Ｐ４で表される＋Ｙの向きに分極された矩形の圧電セラミック板１３ａのＺＸ面に駆動電極１４ａと接地電極１４ｂが設けられた縦振動部１２ａと、矢印Ｐ５で表される＋Ｚの向きに分極された矩形の圧電セラミック板１３ｂのＸＹ面の一方の面にＸ方向に略２等分割された駆動電極１４ｃ・１４ｄが形成され、ＸＹ面の他方の面に接地電極１４ｅが全面的に形成された屈曲振動部１２ｂと、を有しており、縦振動部１２ａと屈曲振動部１２ｂとの間には絶縁板１９が配設されている。
【００４６】
絶縁板１９は、縦振動部１２ａの駆動電極１４ａおよび接地電極１４ｂと屈曲振動部１２ｂの接地電極１４ｅとの接触を防止し、また、駆動電極１４ａと接地電極１４ｅとが近接した部分における絶縁破壊を防止するとともに、屈曲振動部１２ｂに屈曲振動を生じさせるためのクランプとして機能する。なお、圧電セラミック板１３ａ・１３ｂと絶縁板１９とは、エポキシ樹脂接着剤等によって接着することができる。絶縁板１９としては、アルミナ等のセラミックス部材が好適に用いられる。
【００４７】
このような構造を有する振動子１０においては、例えば、駆動電極１４ａに電圧Ｖ＝Ｖ０ｃｏｓωｔの交流電圧を印加すると同時に、駆動電極１４ｃに電圧Ｖ＝Ｖ０ｓｉｎωｔの交流電圧を印加し、かつ、駆動電極１４ｄには駆動電極１４ｃに印加する電圧と位相が１８０度ずれた電圧、つまり電圧Ｖ＝−Ｖ０ｓｉｎωｔの交流電圧を印加すればよい。これにより屈曲振動部１２ｂには、圧電セラミック板１３ｂのＸ方向の中央部（駆動電極１４ｃと駆動電極１４ｄ間）を節とし、駆動電極１４ｃ・１４ｄのそれぞれのＸ方向の中央部を腹とする屈曲振動が生ずる。保持部材７と接頭部材６ａ・６ｂの配設位置は、振動子１の場合と同様に定められる。
【００４８】
振動子１０においても、屈曲振動部１２ｂのＹ方向長さが縦振動部１２ａのＹ方向長さよりも充分に長いために、屈曲振動による発生力が大きくなり、駆動力の大きい超音波モータが実現される。
【００４９】
振動子１０は圧電セラミック板１３ａと圧電セラミック板１３ｂとが接着された構造を有しているが、これらが一体構造を有している断面略Ｌ字型の圧電セラミック部材を用いて超音波モータを構成してもよい。図６は、縦板部１８ａと横板部１８ｂからなる圧電セラミック部材１８を備えた振動子１０Ａの概略斜視図である。この断面Ｌ字型の圧電セラミック部材１８の縦板部１８ａのＺＸ面にそれぞれ駆動電極１４ａと接地電極１４ｂが形成されて縦振動部１２ａ´が形成され、圧電セラミック部材１８の横板部１８ｂのＸＹ面にそれぞれ駆動電極１４ｃ・１４ｄと接地電極１４ｅが形成されて屈曲振動部１２ｂ´が形成されている。振動子１０Ａにおける接頭部材６ａ・６ｂの配設位置と保持部材７の配設位置および振動子１０Ａの駆動方法は、振動子１０と同じであるので、ここでは詳細な説明を省略する。
【００５０】
図７は本発明に係るさらに別の実施形態である振動子２０Ａの概略構造を示す斜視図である。この振動子２０Ａは、図６に示した振動子１０Ａを構成する圧電セラミック部材１８を積層構造としたものである。すなわち、振動子２０Ａは、圧電セラミック薄板２２ａと駆動電極２３ａ／接地電極２３ｂとが原則的に交互に積層されてなる縦振動部２１ａと、圧電セラミック薄板２２ｂと駆動電極２３ｃ・２３ｄ／接地電極２３ｅが交互に積層されてなる屈曲振動部２１ｂと、を有している。
【００５１】
縦振動部２１ａにおいては、駆動電極２３ａと接地電極２３ｂとは一層おきに配置されて、駆動電極２３ａどうしが電気的に接続され、かつ、接地電極２３ｂどうしが電気的に接続されている。また屈曲振動部２１ｂにおいては、駆動電極２３ｃ・２３ｄは同一のＸＹ面においてＸ方向に分かれて配置され、駆動電極２３ｃ・２３ｄと接地電極２３ｅとは一層おきに配置されており、駆動電極２３ｃどうしが電気的に接続され、駆動電極２３ｄどうしが電気的に接続され、接地電極２３ｅどうしが電気的に接続されている。なお、接地電極２３ｂ・２３ｅどうしを互いに電気的に接続してもよい。
【００５２】
圧電セラミック薄板２２ａの分極処理は、駆動電極２３ａと接地電極２３ｂとの間に駆動電極２３ａ側が高電位となるように行われる。また、圧電セラミック薄板２２ｂの分極処理は、駆動電極２３ｃ・２３ｄと接地電極２３ｅとの間に駆動電極２３ｃ・２３ｄ側が高電位となるように行われる。縦振動部２１ａにおいては、接地電極２３ｂと接地電極２３ｅに挟まれた圧電不活性層が屈曲振動部２１ｂ側に形成されており、この圧電不活性層が屈曲振動部２１ｂに屈曲振動を生じさせるためのクランプ層として機能する。
【００５３】
振動子２０Ａにおける保持部材７と接頭部材６ａ・６ｂの配設位置は振動子１０Ａと同様に定められる。また、振動子２０Ａの駆動方法としては、例えば、振動子１０Ａと同様に（つまり振動子１０と同様に）、駆動電極２３ａに電圧Ｖ＝Ｖ０ｃｏｓωｔの交流電圧を印加し、同時に駆動電極２３ｃの表面電極に電圧Ｖ＝Ｖ０ｓｉｎωｔの交流電圧を印加し、かつ、駆動電極２３ｄには駆動電極２３ｃに印加する電圧と位相が１８０度ずれた電圧、つまり電圧Ｖ＝−Ｖ０ｓｉｎωｔの交流電圧を印加する方法が挙げられる。振動子２０Ａにおいては、圧電セラミック薄板２２ａ・２２ｂを用いることによって、駆動電圧を下げることができる。
【００５４】
振動子２０Ａは、好適には、圧電セラミックス粉末をシート成形して得られるグリーンシートを用いた一体焼成法（同時焼成法）により作製することができる。図８は使用するグリーンシートの形態を示す説明図である。駆動電極２３ａとなる電極パターンが印刷されたグリーンシート２５ａと、接地電極２３ｂとなる電極パターンが印刷されたグリーンシート２５ｂとを交互に積層して、上段においては電極パターンが形成されていないグリーンシート２５ｃを数枚重ねる。その上に、駆動電極２３ｃ・２３ｄとなる電極パターンが印刷されたグリーンシート２６ａと、接地電極２３ｅとなる電極パターンが印刷されたグリーンシート２６ｂとを交互に積層する。グリーンシート２５ａ・２５ｂ・２６ａ・２６ｂを熱プレス処理して一体化し、所定の温度で焼成する。こうして得られたＹＺ面やＺＸ面を必要に応じて研削処理し、一層おきに同種の電極を接続する。なお、同種の電極の接続を容易とするために、例えば、グリーンシートに印刷する電極パターンを積層コンデンサ型のパターンとしてもよい。
【００５５】
図９は本発明に係るさらに別の実施形態である振動子３０Ａの概略構造を示す斜視図である。振動子３０Ａは、Ｌ字型の圧電セラミック薄板３２と駆動電極３３ａ・３３ｂ／接地電極３３ｃとが原則的にＸ方向で交互に積層された構成を有しており、Ｙ方向長さの短い矩形部分がＸ方向に伸縮する縦振動部３１ａとなり、Ｙ方向長さの長い矩形部分がＺ方向に屈曲する屈曲振動部３１ｂとなる。なお、振動子３０ＡのＸ方向中央には、接地電極３３ｃに挟まれた圧電不活性な領域が設けられ、かつ、縦振動部３１ａの屈曲振動部３１ｂ側には、Ｘ方向に延在する圧電不活性領域が形成されている。
【００５６】
振動子３０Ａにおける保持部材７と接頭部材６ａ・６ｂの配設位置は振動子１０Ａと同様に定められる。全ての駆動電極３３ａどうしが接続されて、例えば、これに電圧Ｖ＝Ｖ０ｃｏｓωｔの交流電圧が印加される。さらに保持部材７から−Ｘ側に位置する駆動電極３３ｂどうしが接続され、これに電圧Ｖ＝−Ｖ０ｓｉｎωｔの交流電圧が印加される。また、保持部材７から＋Ｘ側に位置する駆動電極３３ｂどうしが接続され、これに電圧Ｖ＝Ｖ０ｓｉｎωｔの交流電圧が印加される。全ての接地電極３３ｃは、圧電セラミック薄板３２とほぼ同形状を有し、各層において縦振動部３１ａと屈曲振動部３１ｂとの間で導通しており、全ての接地電極３３ｃどうしは電気的に接続される。
【００５７】
このように、この振動子３０Ａもまた、図６に示した振動子１０Ａを構成する圧電セラミック部材１８を積層構造としたものであるが、先に説明した振動子２０Ａが圧電セラミック部材１８をＺ方向の積層構造としたものであるのに対し、振動子３０Ａは圧電セラミック部材１８をＸ方向の積層構造としたものである。したがって、振動子２０Ａは圧電セラミック薄板２２ａ・２２ｂに生ずるｄ３１モードの伸縮変位を利用して接頭部材６ａ・６ｂに楕円進行波を生じさせているが、振動子３０Ａでは圧電セラミック薄板３２に生ずるｄ３３モードの伸縮変位を利用することにより、縦振動部３１ａにおいてＸ方向の伸縮振動を発生させ、屈曲振動部３１ｂにおいてはＺ方向の屈曲振動を発生させる。
【００５８】
図１０は本発明に係るさらに別の実施形態である振動子４０の概略構造を示す斜視図である。この振動子４０は、図１に示した振動子１を構成する略Ｌ字型に接続された構造体３ａ・３ｂを略Ｔ字型に変形した形態を有する。
【００５９】
すなわち振動子４０は、矩形の構造体４２ａのＺＸ面に矩形板状の圧電素子４３ａ・４３ｂが配設された構成を有し、圧電素子４３ａ・４３ｂを伸縮のタイミングを合わせてｄ３１モードで駆動することによってＸ方向の伸縮振動が生ずる縦振動部４１ａと、構造体４２ａと同一長さの矩形の構造体４２ｂのＸＹ面に実質的に同じ形状を有する２枚の矩形板状の圧電素子４３ｃ・４３ｄがＸ方向に並べて所定の狭い間隔を開けて配設された構成を有し、圧電素子４３ｃ・４３ｄを伸縮のタイミングを反転させてｄ３１モードで駆動することによってＺ方向の屈曲振動が生じる屈曲振動部４１ｂと、を有している。構造体４２ａ・４２ｂは、構造体４２ａのＹ方向長さが構造体４２ｂのＹ方向長さよりも短く、これらはそのＹＺ面がＴ字型となるように接合されている。
【００６０】
圧電素子４３ａは、圧電素子４３ａを構成する圧電セラミック板の分極の向きが＋Ｙ向きとなるように、構造体４２ａに配設されており（矢印Ｐ１）、圧電素子４３ｂは、圧電素子４３ｂを構成する圧電セラミック板の分極の向きが−Ｙ向きとなるように、構造体４２ａに配設されている（矢印−Ｐ１）。圧電素子４３ａ・４３ｂの表面電極は電気的に接続されている。また、圧電素子４３ｃは、圧電素子４３ｃを構成する圧電セラミック板の分極の向きが＋Ｚ向きとなるように、構造体４２ｂに配設されており（矢印Ｐ２）、圧電素子４３ｄは、圧電素子４３ｄを構成する圧電セラミック板の分極の向きが−Ｚ向きとなるように、構造体４２ｂに配設されている（矢印Ｐ３）。圧電素子４３ｃ・４３ｄの表面電極は電気的に接続されている。構造体４２ａ・４２ｂはアース電極として使用される。
【００６１】
振動子４０における接頭部材６ａ・６ｂと保持部材７の配設位置は、振動子１と同様に定められる。振動子４０の駆動方法は図１に示した振動子１と同様であるので、ここでは詳細な説明を割愛する。
【００６２】
図１１は本発明に係るさらに別の実施形態である振動子５０の概略構造を示す斜視図である。この振動子５０は、矩形の構造体５２ａのＺＸ面に矩形板状の圧電素子５３ａが配設され、この圧電素子５３ａをｄ３１モードで駆動することによってＸ方向の伸縮振動を生ずる第１の縦振動部５１ａと、実質的に縦振動部５１ａと同じ構造を有する第２の縦振動部５１ａ´と、構造体５２ａと同一長さの略矩形の構造体５２ｃのＸＹ面に実質的に同じ形状を有する２枚の矩形板状の圧電素子５３ｃ・５３ｄがＸ方向に並べて所定の狭い間隔をあけて配設された構成を有し、圧電素子５３ｃ・５３ｄを伸縮のタイミングを反転させてｄ３１モードで駆動することによってＺ方向の屈曲振動を生じさせる屈曲振動部５１ｂと、を有している。
【００６３】
第２の縦振動部５１ａ´は、矩形の構造体５２ｂのＺＸ面に矩形板状の圧電素子５３ｂが配設された構造を有し、この圧電素子５３ｂをｄ３１モードで駆動することによって第２の縦振動部５１ａ´にはＸ方向の伸縮振動が生ずる。圧電素子５３ａ・５３ｂは、伸縮のタイミングを合わせて駆動する。
【００６４】
振動子５０においては、屈曲振動部５１ｂの発生力を大きくするために、構造体５２ａ・５２ｂのＹ方向での合計の長さが、構造体５２ｃのＹ方向長さよりも短くなるように、これらはそのＹＺ断面の形状が略Π字型となるように接合されている。振動子５０の駆動方法は、図１０に示した振動子４０と同様であるので、ここでは詳細な説明を省略する。なお、振動子５０においては、振動子４０の縦振動部４１ａと同様に、構造体５２ａ・５２ｂを２枚の圧電素子で挟んだ形態としてもよい。
【００６５】
図１２（ａ）は本発明に係るさらに別の実施形態である振動子６０Ａの概略構造を示す側面図であり、図１２（ｂ）は図１２（ａ）の側面図中に示すＡＡ線での断面図であり、図１２（ｃ）は図１２（ａ）の側面図中に示すＢＢ線での断面図である。振動子６０Ａは、円筒形状を有する圧電セラミックス管６１と、圧電セラミックス管６１の周回りで略４等分割され、かつ、径方向で対向する一対の電極のみが長手方向（Ｚ方向）で略２等分割されて形成される駆動電極６２ａ・６２ｂ・６２ｃ・６２ｄ・６２ｅ・６２ｆと、圧電セラミックス管６１の内周面の全体に形成された接地電極６２ｇと、圧電セラミックス管６１の一方の端面に取り付けられたキャップ６３と、キャップ６３の中央部に設けられた接頭部材６４と、を有している。なお、キャップ６３と接頭部材６４とは一体的に形成されていてもよい。
【００６６】
圧電セラミックス管６１は放射状に径方向で分極されており、駆動電極６２ａ〜６２ｄは、駆動電極６２ａ・６２ｄどうしが電気的に接続され、駆動電極６２ｂ・６２ｃどうしが電気的に接続されるように、たすき掛けの形態で接続されている（図１２（ａ））。また、駆動電極６２ｅ・６２ｆどうしが電気的に接続されている（図１２（ｂ）、（ｃ））。
【００６７】
振動子６０Ａでは、例えば、駆動電極６２ａ・６２ｄに電圧Ｖ＝Ｖ０ｓｉｎωｔの交流電圧を印加し、これと同時に、駆動電極６２ｂ・６２ｃには電圧Ｖ＝−Ｖ０ｓｉｎωｔの交流電圧を印加し、駆動電極６２ｅ・６２ｆには電圧Ｖ＝Ｖ０ｃｏｓωｔの交流電圧を印加する。駆動電極６２ａ〜６２ｄが配置された部分は、屈曲振動部として機能し、Ｙ方向での変位を発生させる。これに対して、駆動電極６２ｅ・６２ｆが配置された部分は縦振動部として機能し、Ｚ方向での変位を発生される。その結果、圧電セラミックス管６１の端面においてＹＺ面内で楕円軌跡を描く楕円進行波を発生させることができる。したがって、接頭部材６４に被移動体（図示せず）を所定の圧力で接触させると、この被移動体をＹ方向で移動させることができる。なお、振動子６０Ａにおいては、駆動電極６２ａ・６２ｄ間と、駆動電極６２ｂ・６２ｃ間が振動の節となるので、この部分で振動子６０Ａを保持する。
【００６８】
図１３（ａ）は本発明に係るさらに別の実施形態である振動子７０Ａの概略構造を示す側面図である。この振動子７０Ａは、図１２に示した振動子６０Ａを積層構造へと変形させたものである。すなわち、振動子７０Ａは、柱状構造体７１と、柱状構造体７１の一方の端面に取り付けられたキャップ６３と、キャップ６３の中央部に設けられた配設された接頭部材６４と、を有している。柱状構造体７１は、平板リング状の圧電セラミックリング７２と、駆動電極７３ａ・７３ｂ・７３ｃ・７３ｄと、接地電極７３ｅとを有しており、圧電セラミックリング７２と駆動電極７３ａ〜７３ｄ／接地電極７３ｅとが、圧電セラミックリング７２の厚み方向に原則的に交互に積層された構造を有している。
【００６９】
図１３（ｂ）は駆動電極７３ａ〜７３ｄの電極パターンを示す平面図であり、図１３（ｃ）は接地電極７３ｃの電極パターンを示す平面図である。駆動電極７３ａ〜７３ｄはそれぞれ、径方向で略４等分割された１／４円弧状の形状を有し、接地電極７３ｃはリング状の形状を有する。全ての接地電極７３ｅは電気的に接続され、積層方向（Ｚ方向）の中央部には、接地電極７３ｅに挟まれた圧電セラミックリング７２ａが設けられている。この圧電不活性な圧電セラミックリング７２ａにおいて、振動子７０Ａを保持することができる。
【００７０】
駆動電極７３ａは、Ｚ方向中央部からキャップ６３側に位置しているものどうしが電気的に接続され、例えば、これに電圧Ｖ＝Ｖ０ｓｉｎωｔの交流電圧が印加される。また、駆動電極７３ａは、Ｚ方向中央部からキャップ６３が配設されていない端面（以下「開放端」という）に位置しているものどうしが電気的に接続され、これに電圧Ｖ＝−Ｖ０ｓｉｎωｔの交流電圧が印加される。同様に、駆動電極７３ｂは、Ｚ方向中央部からキャップ６３側に位置しているものどうしが電気的に接続され、これに電圧Ｖ＝−Ｖ０ｓｉｎωｔの交流電圧が印加される。また、駆動電極７３ｂは、Ｚ方向中央部から開放端側に位置しているものどうしが電気的に接続され、これに電圧Ｖ＝Ｖ０ｓｉｎωｔの交流電圧が印加される。さらに、全ての駆動電極７３ｃと駆動電極７３ｄが電気的に接続され、これに電圧Ｖ＝Ｖ０ｃｏｓωｔの交流電圧が印加される。
【００７１】
これにより、柱状構造体７１においては、駆動電極７３ａ・７３ｂが配置された部分が屈曲振動部となり、駆動電極７３ｃ・７３ｄが配置された部分が縦振動部となって、接頭部材６４にＹＺ面内で楕円軌跡を描く楕円進行波を発生させることができる。
【００７２】
図１４は本発明に係るさらに別の実施形態である振動子１０Ｂの概略構造を示す斜視図である。この振動子１０Ｂは、先に図６に示した振動子１０Ａの変形例ということができる。振動子１０Ｂは、断面Ｌ字型の圧電セラミック部材１８の縦板部１８ａのＺＸ面の一方にＸ方向で略２等分割された２つの駆動電極１４ａ´・１４ａ″が形成され、かつ、ＺＸ面の他方に全面的に接地電極１４ｂが形成され、さらに横板部１８ｂのＸＹ面にそれぞれ駆動電極１４ｃ・１４ｄと接地電極１４ｅが形成された構造を有している。駆動電極１４ａ´と駆動電極１４ｄが電気的に接続されており、駆動電極１４ａ″と駆動電極１４ｃが電気的に接続されている。
【００７３】
振動子１０Ｂでは、駆動電極１４ａ´が配設されている部分と駆動電極１４ｄが配設されている部分との間で伸縮振動を生じさせ、かつ、この伸縮のタイミングとずらして駆動電極１４ａ″が配設されている部分と駆動電極１４ｃが配設されている部分との間で伸縮振動を生じさせることによって、接頭部材６ａ・６ｂに楕円進行波を生じさせる。振動子１０Ｂにおいても、保持部材７と接頭部材６ａ・６ｂの配設位置は振動子１０Ａと同様に定められる。
【００７４】
したがって、振動子１０Ｂの駆動方法としては、例えば、駆動電極１４ａ´・１４ｄに電圧Ｖ＝Ｖ０ｓｉｎωｔの交流電圧を印加すると同時に、駆動電極１４ａ″・１４ｃに電圧Ｖ＝Ｖ０ｃｏｓωｔの交流電圧を印加する方法が挙げられる。振動子１０Ｂにおいても、横板部１８ｂで発生するＺ方向の発生力が大きくなるために、駆動力の大きな超音波モータが実現される。
【００７５】
図１５は本発明に係るさらに別の実施形態である振動子２０Ｂの概略構造を示す斜視図である。この振動子２０Ｂは、図１４に示した振動子１０Ｂを構成する圧電セラミック部材１８をＺ方向の積層構造としたものである。振動子２０Ｂは、圧電セラミック薄板２８ａと駆動電極２９ａ・２９ｂ／接地電極２９ｃとが原則的に交互に積層された第１積層部２７ａと、圧電セラミック薄板２８ｂと駆動電極２９ｄ・２９ｅ／接地電極２９ｆとが交互に積層されてなる第２積層部２７ｂと、を有している。第１積層部２７ａにおいては、接地電極２９ｃと接地電極２９ｆに挟まれた圧電不活性層が第２積層部２７ｂ側に形成されている。圧電セラミック薄板２８ｂは圧電セラミック薄板２８ａよりもＹ方向長さが長い。
【００７６】
第１積層部２７ａにおいては、駆動電極２９ａ・２９ｂは同一のＸＹ面においてＸ方向に分かれて配置され、駆動電極２９ａ・２９ｂと接地電極２９ｃとは一層おきに配置されている。同様に、第２積層部２７ｂにおいては、駆動電極２９ｄ・２９ｅは同一のＸＹ面においてＸ方向に分かれて配置され、駆動電極２９ｄ・２９ｅと接地電極２９ｆとは一層おきに配置されている。振動子２０Ｂにおける保持部材７と接頭部材６ａ・６ｂの配設位置は振動子１０Ｂと同様に定められる。
【００７７】
振動子１０Ｂと同様の振動を振動子２０Ｂに生じさせるために、例えば、駆動電極２９ａどうしを電気的に接続して、例えば、これに電圧Ｖ＝Ｖ０ｓｉｎωｔの交流電圧を印加する。また、駆動電極２９ｂどうしを電気的に接続して、これに電圧Ｖ＝Ｖ０ｃｏｓωｔの交流電圧を印加する。さらに、駆動電極２９ｄどうしを電気的に接続して、これに電圧Ｖ＝Ｖ０ｓｉｎωｔの交流電圧を印加する。さらにまた、駆動電極２９ｅどうしを接続して、これに電圧Ｖ＝Ｖ０ｃｏｓωｔの交流電圧を印加する。これにより、接頭部材６ａ・６ｂに楕円進行波を生じさせることができる。なお、振動子２０Ｂは、先に説明した振動子２０Ａと同様の方法によって作製することができる。このような積層構造は、ＹＺ面の形状が略Ｔ字型、略Π字型の振動子にも適用することができる。
【００７８】
図１６は本発明に係るさらに別の実施形態である振動子３０Ｂの概略構造を示す斜視図である。図１６に示す振動子３０Ｂは、図１４に示した振動子１０Ｂを構成する圧電セラミック部材１８を、Ｘ方向の積層構造を有するように変形させたものである。すなわち、振動子３０Ｂは、Ｌ字型の圧電セラミック薄板３６と駆動電極３７ａ・３７ｂ／接地電極３７ｃとが原則的にＸ方向で交互に積層された構成を有している。また、振動子３０Ｂにおける保持部材７と接頭部材６ａ・６ｂの配設位置は振動子３０Ａと同様に定められている。
【００７９】
全ての接地電極３７ｃは圧電セラミック薄板３６とほぼ同形状であり、全ての接地電極３７ｃどうしが電気的に接続されている。駆動電極３７ａのうち保持部材７の配設位置から−Ｘ側に位置するものどうしが電気的に接続され、例えば、これに電圧Ｖ＝Ｖ０ｓｉｎωｔの交流電圧が印加される。また、駆動電極３７ｂのうち保持部材７の配設位置から−Ｘ側に位置するものどうしが電気的に接続され、これに電圧Ｖ＝Ｖ０ｃｏｓωｔの交流電圧が印加される。さらに、駆動電極３７ａのうち保持部材７の配設位置から＋Ｘ側に位置するものどうしが電気的に接続され、これに電圧Ｖ＝Ｖ０ｃｏｓωｔの交流電圧が印加される。さらにまた、駆動電極３７ｂのうち保持部材７の配設位置から＋Ｘ側に位置するものどうしが電気的に接続され、これに電圧Ｖ＝Ｖ０ｓｉｎωｔの交流電圧が印加される。
【００８０】
こうして振動子３０Ｂにおいては、圧電セラミック薄板３６に生ずるｄ３３モードの伸縮変位を利用することにより、接頭部材６ａ・６ｂに楕円進行波を生じさせることができる。なお、振動子３０Ｂは、先に説明した振動子２０Ａと同様の方法によって作製することができる。このような積層構造は、ＹＺ面の形状が略Ｔ字型、略Π字型の振動子にも適用することができる。
【００８１】
図１７（ａ）は本発明に係るさらに別の実施形態である振動子６０Ｂの概略構造を示す側面図であり、図１７（ｂ）は側面図中のＡＡ断面図であり、図１７（ｃ）は側面図中のＢＢ断面図である。この振動子６０Ｂは、円筒形状を有する圧電セラミックス管６１と、圧電セラミックス管６１の外周面に長手方向（Ｚ方向）で略２等分割され、かつ、周回りで略２等分割されて形成された駆動電極６７ａ・６７ｂ・６７ｃ・６７ｄと、圧電セラミックス管６１の内周面の全体に形成された接地電極６７ｅと、圧電セラミックス管６１の一方の端面に配設されたキャップ６３と、キャップ６３の中央部に設けられた接頭部材６４と、を有している。
【００８２】
圧電セラミックス管６１は、例えば、接地電極６７ｅと駆動電極６７ａ〜６７ｄの間に高電圧を印加することによって、放射状に径方向で分極されている。駆動電極６７ａ〜６７ｄは、駆動電極６７ａ・６７ｄどうしが電気的に接続され、かつ、駆動電極６７ｂ・６７ｃどうしが電気的に接続されるように、たすき掛けの形態で接続されている。
【００８３】
振動子６０Ｂでは、例えば、駆動電極６７ａ・６７ｄに電圧Ｖ＝Ｖ０ｃｏｓωｔの交流電圧を印加し、駆動電極６７ｂ・６７ｃに電圧Ｖ＝Ｖ０ｓｉｎωｔの交流電圧を印加することによって、圧電セラミックス管６１の端面においてＹＺ面内で楕円軌跡を描く楕円進行波を発生させることができる。なお、被移動体の移動の向きは、駆動電極６７ａ・６７ｄに印加する電圧と駆動電極６７ｂ・６７ｃに印加する電圧の位相を変えることによって決めることができる。振動子６０Ｂにおいては、Ｚ方向中央部が振動の節となるので、この部分で振動子６０Ｂを保持する。
【００８４】
図１８（ａ）は本発明に係るさらに別の実施形態である振動子７０Ｂの概略構造を示す側面図である。この振動子７０Ｂは、図１７に示した振動子６０Ｂを積層構造へと変形させたものである。すなわち、振動子７０Ｂは、柱状構造体７５と、柱状構造体７５の一方の端面に取り付けられたキャップ６３と、キャップ６３の中央部に設けられた配設された接頭部材６４と、を有している。柱状構造体７５は、平板リング状の圧電セラミックリング７６と、駆動電極７７ａ・７７ｂと、接地電極７７ｃとを有しており、圧電セラミックリング７６と駆動電極７７ａ・７７ｂ／接地電極７７ｃとが、圧電セラミックリング７６の厚み方向に原則的に交互に積層された構造を有している。
【００８５】
図１８（ｂ）は駆動電極７７ａ・７７ｂの電極パターンを示す平面図であり、図１８（ｃ）は接地電極７７ｃの電極パターンを示す平面図である。駆動電極７７ａ・７７ｂは、径方向で略２等分割された半円弧形状を有し、接地電極７７ｃはリング状の形状を有する。全ての接地電極７７ｃは電気的に接続され、積層方向（Ｚ方向）の中央部には、接地電極７７ｃに挟まれた圧電セラミックリング７６ａが設けられている。この圧電不活性な圧電セラミックリング７６ａにおいて、振動子７０Ｂを保持することができる。
【００８６】
駆動電極７７ａは、Ｚ方向中央部からキャップ６３側に位置しているものどうしが電気的に接続され、例えば、これに電圧Ｖ＝Ｖ０ｓｉｎωｔの交流電圧が印加される。また、駆動電極７７ａは、Ｚ方向中央部から開放端側に位置しているものどうしが電気的に接続され、これに電圧Ｖ＝Ｖ０ｃｏｓωｔの交流電圧が印加される。同様に、駆動電極７７ｂは、Ｚ方向中央部からキャップ６３側に位置しているものどうしが電気的に接続され、これに電圧Ｖ＝Ｖ０ｃｏｓωｔの交流電圧が印加される。また、駆動電極７７ｂは、Ｚ方向中央部から開放端側に位置しているものどうしが電気的に接続され、これに電圧Ｖ＝Ｖ０ｓｉｎωｔの交流電圧が印加される。これにより、接頭部材６４にＹＺ面内で楕円軌跡を描く楕円進行波を発生させることができる。
【００８７】
以上、本発明の実施の形態について説明してきたが、本発明がこのような形態に限定されるものでない。振動子１等の駆動電圧波形としてｓｉｎ波やｃｏｓ波を挙げたが、これに代えて三角波や矩形パルス波を用いることも可能である。また、例えば振動子１について、接頭部材６ａ・６ｂに楕円進行波を生じさせる例として、圧電素子４ａの表面電極に電圧Ｖ＝Ｖ０ｃｏｓωｔを、圧電素子４ｂ・４ｃの表面電極に電圧Ｖ＝Ｖ０ｓｉｎωｔを印加した場合について説明したが、圧電素子４ａの表面電極に印加する電圧と圧電素子４ｂ・４ｃの表面電極に印加する電圧との位相差は完全に９０度である必要はなく、被移動体８０を動かすことができる範囲で、位相差を９０度からずらしてもよい。
【００８８】
さらに、例えば、振動子１をＹ方向に複数連ねることによって、より駆動力の大きな超音波モータを具現化することができる。上記説明においては、接頭部材を縦振動部に配置し、保持部材を屈曲振動部に配置した形態を示したが、これとは逆に、接頭部材を屈曲振動部に配置し、保持部材を縦振動部に配置することもできる。この場合には、接頭部材は駆動電極に接することとなるために、接頭部材材料としては絶縁体（例えば、絶縁性セラミックス等）が好適に用いられる。被移動体は直線方向に移動するスライダに限定されるものではなく、回転体であってもよい。
【００８９】
さらに、図１０に示した振動子４０や図１１に示した振動子５０は、Ｔ字型やΠ字型の圧電セラミック部材を用いた構成に変形させることができ、さらにこのような圧電セラミック部材を積層構造とすることが可能なことはいうまでもない。振動子５０では、屈曲振動部５１ｂを底壁とし、縦振動部５１ａ・５１ａ´を側壁とすると、これらによって囲まれる溝に、部品や流体を流す用途に用いることも可能である。このような使用方法は、円筒形の形状を有する振動子６０Ａ等でも同様に行うことができる。
【００９０】
【発明の効果】
上述の通り、本発明の振動子および超音波モータによれば、その駆動力が大きいために、例えば、重量物の搬送を行うことができるようになるという効果を奏する。
【図面の簡単な説明】
【図１】本発明に係る振動子の一実施形態を示す概略斜視図。
【図２】図１に示す振動子を用いた超音波モータの概略の構成を示す側面図および断面図。
【図３】図１に示す振動子の入力アドミッタンス特性を示す説明図。
【図４】本発明に係る振動子の別の実施形態を示す概略斜視図。
【図５】本発明に係る振動子のさらに別の実施形態を示す概略斜視図。
【図６】本発明に係る振動子のさらに別の実施形態を示す概略斜視図。
【図７】本発明に係る振動子のさらに別の実施形態を示す概略斜視図。
【図８】図７に示す振動子の作製に用いられるグリーンシートの構成を示す説明図。
【図９】本発明に係る振動子のさらに別の実施形態を示す概略斜視図。
【図１０】本発明に係る振動子のさらに別の実施形態を示す概略斜視図。
【図１１】本発明に係る振動子のさらに別の実施形態を示す概略斜視図。
【図１２】本発明に係る振動子のさらに別の実施形態を示す概略側面図および断面図。
【図１３】本発明に係る振動子のさらに別の実施形態を示す概略側面図、およびこの振動子を構成する駆動電極と接地電極の平面図。
【図１４】本発明に係る振動子のさらに別の実施形態を示す概略斜視図。
【図１５】本発明に係る振動子のさらに別の実施形態を示す概略斜視図。
【図１６】本発明に係る振動子のさらに別の実施形態を示す概略斜視図。
【図１７】本発明に係る振動子のさらに別の実施形態を示す概略側面図および断面図。
【図１８】本発明に係る振動子のさらに別の実施形態を示す概略側面図、およびこの振動子を構成する駆動電極と接地電極の平面図。
【図１９】従来の超音波モータの概略構成を示す説明図。
【図２０】図１９に示す超音波モータの入力アドミッタンス特性を示す説明図。
【符号の説明】
１・１Ａ；振動子、２ａ；縦振動部、２ｂ；屈曲振動部、３ａ・３ｂ；構造体、４ａ〜４ｆ；圧電素子、６ａ・６ｂ・６ｄ〜６ｆ；接頭部材、７・７ａ・７ｂ；保持部材、８；押圧手段、９；固定手段、１０・１０Ａ・１０Ｂ；振動子、１２ａ・１２ａ´；縦振動部、１２ｂ・１２ｂ´；屈曲振動部、１３ａ・１３ｂ；圧電セラミック板、１４ａ・１４ａ´・１４ａ″・１４ｃ・１４ｄ・１４´・１４″；駆動電極、１４ｂ・１４ｅ；接地電極、１８；圧電セラミック部材、１８ａ；縦板部、１８ｂ；横板部、１９；絶縁板、２０Ａ・２０Ｂ；振動子、２１ａ；縦振動部、２１ｂ；屈曲振動部、２２ａ・２２ｂ；圧電セラミック薄板、２３ａ・２３ｃ・２３ｄ；駆動電極、２３ｂ・２３ｅ；接地電極、２５ａ・２５ｂ・２５ｃ・２６ａ・２６ｂ；グリーンシート、２７ａ；第１積層部、２７ｂ；第２積層部、２８ａ・２８ｂ；圧電セラミック薄板、２９ａ・２９ｂ・２９ｄ・２９ｅ；駆動電極、２９ｃ・２９ｆ；接地電極、３０Ａ・３０Ｂ；振動子、３１ａ；縦振動部、３１ｂ；屈曲振動部、３２；圧電セラミック薄板、３３ａ・３３ｂ；駆動電極、３３ｃ；接地電極、３６圧電セラミック薄板、；３７ａ・３７ｂ；駆動電極、３７ｃ；接地電極、４０；振動子、４１ａ；縦振動部、４１ｂ；屈曲振動部、４２ａ・４２ｂ；構造体、４３ａ〜４３ｄ；圧電素子、５０；振動子、５１ａ・５１ａ´；縦振動部、５１ｂ；屈曲振動部、５２ａ・５２ｂ・５２ｃ；構造体、５３ａ〜５３ｄ；圧電素子、６０Ａ・６０Ｂ；振動子、６１；圧電セラミックス管、６２ａ〜６２ｆ；駆動電極、６２ｇ；接地電極、６３；キャップ、６４；接頭部材、６７ａ〜６７ｄ；駆動電極、６７ｅ；接地電極、７０Ａ・７０Ｂ；振動子、７１；柱状構造体、７２・７２ａ；圧電セラミックリング、７３ａ〜７３ｄ；駆動電極、７３ｅ；接地電極、７５；柱状構造体、７６；圧電セラミックリング、７７ａ・７７ｂ；駆動電極、７７ｃ；接地電極、８０；被移動体、１００：超音波モータ、２００；超音波モータ、２０１；圧電板、２０２；接頭部材、２０３；第１保持部材、２０４；第２保持部材、２０５ａ〜２０５ｄ；分割電極、２１０；被移動体[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a vibrator that vibrates in a predetermined vibration mode by driving a piezoelectric element, and an ultrasonic motor including the vibrator.
[0002]
[Prior art]
As an ultrasonic motor using an elliptical traveling wave of a piezoelectric vibrator, Japanese Patent Application Laid-Open No. 7-184382 (Patent Document 1) discloses a rectangular piezoelectric plate 201 made of a piezoelectric material and a piezoelectric plate as shown in FIG. A prefix member 202 provided at the center of the side surface of the short side of 201 and in contact with the moving body 210, a first holding member 203 for rigidly holding one long side of the piezoelectric plate 201, and the other of the piezoelectric plate 201. An ultrasonic motor 200 having a second holding member 204 for elastically holding a short side and a long side is disclosed.
[0003]
Four divided electrodes 205a to 205d are formed on the surface of the piezoelectric plate 201, the divided electrodes 205a and 205d are electrically connected, and the divided electrodes 205b and 205c are electrically connected. A ground electrode (not shown) is formed on almost the entire back surface of the piezoelectric plate 201. By applying a unipolar asymmetric pulse voltage having an inverted sign to the divided electrodes 205a and 205d and the divided electrodes 205b and 205c, an elliptical traveling wave in which the longitudinal vibration mode and the bending vibration mode are combined is applied to the tip of the prefix member 202. Can be caused. The moving object 210 in contact with the prefix member 202 moves in the + X direction or the −X direction in FIG. 19 according to the direction of the elliptical traveling wave of the prefix member 202.
[0004]
[Patent Document 1]
JP-A-7-184382 (pages 5 and 6, FIG. 1)
[0005]
[Problems to be solved by the invention]
The input admittance characteristics of the bending vibration mode and the longitudinal vibration mode of such an ultrasonic motor 200 are as shown in FIG. 20, and in the ultrasonic motor 200, the admittance of the bending vibration mode is smaller than the admittance of the longitudinal vibration mode. You can see that it is. This indicates that it is difficult to obtain a large driving force in the ultrasonic motor 200 because the amplitude in the bending vibration mode is smaller than the amplitude in the longitudinal vibration mode.
[0006]
The present invention has been made in view of such circumstances, and has as its object to provide a vibrator having a large driving force and an ultrasonic motor including the vibrator.
[0007]
[Means for Solving the Problems]
According to a first aspect of the present invention, a vertical vibrating portion having a substantially rectangular shape and extending and contracting in a longitudinal direction thereof,
A bending vibration portion having a substantially rectangular shape having substantially the same length as the longitudinal vibration portion, and bending and vibrating in a thickness direction thereof,
A vibrator comprising:
The stretching vibration direction of the longitudinal vibration part and the bending vibration direction of the bending vibration part are orthogonal, and the longitudinal direction of the longitudinal vibration part and the longitudinal direction of the bending vibration part match,
A vibrator is provided, wherein a length of the bending vibration portion in a direction orthogonal to the bending vibration direction and the stretching vibration direction is longer than a length of the longitudinal vibration portion.
[0008]
In such a vibrator, the longitudinal vibrating part and the bending vibrating part are connected in a substantially L-shaped cross section or a substantially T-shaped cross section.
[0009]
According to a second aspect of the present invention, a plurality of longitudinal vibrating portions having a substantially rectangular shape, arranged so that their main surfaces are parallel at predetermined intervals, and vibrating in the longitudinal direction thereof,
A bending vibration portion having a substantially rectangular shape having substantially the same length as the length of the vertical vibration portion, and bending and vibrating in its thickness direction;
A vibrator comprising:
The stretching vibration direction of the longitudinal vibration part and the bending vibration direction of the bending vibration part are orthogonal, and the longitudinal direction of the longitudinal vibration part and the longitudinal direction of the bending vibration part match,
A vibrator, wherein a length of the bending vibration portion in a direction orthogonal to the bending vibration direction and the stretching vibration direction is longer than a total length of the plurality of longitudinal vibration portions. You.
[0010]
In the vibrators according to the first and second aspects, a vibrator in which a first plate-shaped piezoelectric element is provided on one or both main surfaces of a first rectangular structure is used as a longitudinal vibrator. In addition, as the bending vibration portion, a member in which a second plate-shaped piezoelectric element is provided on the surface of a second rectangular structure can be used. Here, it is preferable that the first rectangular structure and the second rectangular structure are integrally formed. Alternatively, a substantially rectangular first piezoelectric ceramic plate having an electrode formed on a main surface is used as a vertical vibrating portion, and a substantially rectangular second piezoelectric ceramic plate having an electrode formed on a main surface is used as a bending vibrating portion. Is also preferred. It is preferable that the first piezoelectric ceramic plate and the second piezoelectric ceramic plate are integrally formed.
[0011]
In the vibrator according to the first and second aspects, the longitudinal vibrating portion and the bending vibrating portion may have a structure in which a plurality of piezoelectric ceramic thin plates and electrodes are alternately stacked. As a result, the drive voltage can be reduced. Both the laminating direction of the longitudinal vibrating part and the laminating direction of the bending vibrating part may be matched with the bending vibration direction of the bending vibrating part or may be matched with the longitudinal direction of the bending vibrating part.
[0012]
According to a third aspect of the present invention, a first structure having a substantially rectangular shape and at least a first drive unit and a second drive unit having substantially the same shape in the longitudinal direction thereof are arranged. When,
A third drive unit and a fourth drive unit having substantially the same length as the first structure, having a thickness shorter than the width of the first structure, and having substantially the same shape in the longitudinal direction. A second structure having at least a drive unit,
A vibrator comprising:
A side surface in a width direction of the second structure is connected to a main surface of the first structure such that the first drive unit and the fourth drive unit are located diagonally,
The first drive unit and the fourth drive unit are expanded and contracted in phase, and the second drive unit and the third drive unit are in phase and shifted from the first drive unit by approximately 90 degrees. The vibrator is characterized in that an elliptical traveling wave is generated at a predetermined position between the first structural body and the second structural body by expanding and contracting the first and second structures.
[0013]
According to a fourth aspect of the present invention, a longitudinal vibrating portion having a substantially rectangular shape and vibrating in the longitudinal direction thereof,
A bending vibration portion having a substantially rectangular shape having substantially the same length as the longitudinal vibration portion, and bending and vibrating in a thickness direction thereof,
With
A vibrator in which a stretching vibration direction of the longitudinal vibration part and a bending vibration direction of the bending vibration part are orthogonal, and a longitudinal direction of the longitudinal vibration part and a longitudinal direction of the bending vibration part coincide with each other,
A vibrator is provided, wherein an input admittance of the bending vibration section is 60% or more of an input admittance of the longitudinal vibration section.
In the vibrator having such an input admittance characteristic, the driving force can be increased because the generated force in the bending vibration mode is increased.
[0014]
According to a fifth aspect of the present invention, a cylindrical piezoelectric ceramic member,
A common electrode provided on the inner peripheral surface of the piezoelectric ceramic member and used as a ground electrode,
A drive electrode provided in a predetermined pattern on the outer peripheral surface of the piezoelectric ceramic member so that an elliptical traveling wave is generated substantially at the center of the end surface of the piezoelectric ceramic member by applying an alternating voltage in an ultrasonic region,
A vibrator characterized by comprising:
[0015]
As one form of the drive electrode in the vibrator according to the fifth aspect, four electrode elements formed by being approximately equally divided around the circumference of the piezoelectric ceramic member and being substantially equally divided in the longitudinal direction are formed. And a form in which two sets of electrode groups are crossed and connected so as to be formed. Further, as another form of the drive electrode, one of the two sets of electrodes which are substantially equally divided around the circumference of the piezoelectric ceramic member and which are opposed in the radial direction of the piezoelectric ceramic member are formed of the piezoelectric ceramic member. There is a form having six electrode elements formed by being substantially equally divided in the longitudinal direction. In this case, four electrode elements which are substantially equally divided in the longitudinal direction of the piezoelectric ceramic member are provided. Two sets of electrode groups are formed by hooking and connecting, and two sets of electrode elements that are not divided in the longitudinal direction of the piezoelectric ceramic member are connected to each other to form one set of electrode groups.
[0016]
According to a sixth aspect of the present invention, a cylindrical structure in which flat-plate-shaped piezoelectric ceramic rings and electrodes are alternately stacked, a disk member disposed on an end face of the cylindrical structure, A vibrator having
The electrode is
Drive electrodes substantially equally divided into a predetermined number around the circumference of the piezoelectric ceramic ring,
A ring-shaped ground electrode having substantially the same shape as the main surface of the piezoelectric ceramic ring,
Has,
The drive electrodes are electrically connected to form a plurality of electrode groups,
A vibrator characterized in that an elliptical traveling wave is generated at a substantially central portion of an end face of the disk member by applying an alternating voltage in an ultrasonic region to the plurality of electrode groups.
[0017]
In the vibrator according to the sixth aspect, the form of the drive electrode may be a form having a substantially semicircular shape that is roughly equally divided in the radial direction, or a form of approximately 1 / that is roughly divided into four in the radial direction. A form having a four-arc shape is exemplified. It is preferable to provide a piezoelectric inactive piezoelectric ceramic ring sandwiched between ground electrodes at the center in the stacking direction of the piezoelectric ceramic ring and the electrode. In the vibrators according to the fifth and sixth aspects, a large driving force is obtained because the generated force in the longitudinal direction of the piezoelectric ceramic tube or the cylindrical structure is increased.
[0018]
According to the present invention, there is provided an ultrasonic motor including the above-described vibrator.
That is, according to the seventh aspect of the present invention, the vertical vibrating portion has a substantially rectangular shape, and expands and contracts in its longitudinal direction, and has a substantially rectangular shape having substantially the same length as the longitudinal vibrating portion, A flexural vibration portion that flexurally vibrates in the thickness direction thereof, wherein a stretching vibration direction of the longitudinal vibration portion is orthogonal to a flexural vibration direction of the flexural vibration portion, and a longitudinal direction of the longitudinal vibration portion and the flexural vibration portion. A vibrator having the same longitudinal direction,
A prefix member disposed near an antinode of vibration in the bending vibration direction generated in the longitudinal vibration portion due to the bending vibration of the bending vibration portion,
A holding member disposed in the vicinity of a node of bending vibration generated in the bending vibration section in the bending vibration section;
Holding means for holding the holding member,
Pressing means for pressing the holding means against the moving body so that the prefix member is pressed against the moving body with a predetermined force;
With
In the vibrator, the length of the bending vibration portion in a direction orthogonal to the bending vibration direction and the stretching vibration direction is longer than the length of the longitudinal vibration portion,
An ultrasonic motor, wherein the moving object is moved in a predetermined direction by the expansion and contraction vibration of the longitudinal vibration portion and the bending vibration of the bending vibration portion being combined to generate an elliptical motion in the prefix member. Is provided.
[0019]
According to an eighth aspect of the present invention, a plurality of vertical vibrating portions each having a substantially rectangular shape, arranged at predetermined intervals so that their main surfaces are parallel to each other, and vibrating in a longitudinal direction thereof, A bending vibration portion having a substantially rectangular shape having a length substantially the same as the length of the vibration portion, and having a bending vibration portion that bends and vibrates in a thickness direction thereof, wherein a stretching vibration direction of the longitudinal vibration portion and a bending vibration direction of the bending vibration portion Are orthogonal, and a vibrator in which the longitudinal direction of the longitudinal vibration portion and the longitudinal direction of the bending vibration portion match,
A prefix member disposed near an antinode of vibration in the bending vibration direction generated in the longitudinal vibration portion due to the bending vibration of the bending vibration portion,
A holding member disposed in the vicinity of a node of bending vibration generated in the bending vibration section in the bending vibration section;
Holding means for holding the holding member,
Pressing means for pressing the holding means against the moving body so that the prefix member is pressed against the moving body with a predetermined force;
With
In the vibrator, a length of the bending vibration portion in a direction orthogonal to the bending vibration direction and the stretching vibration direction is longer than a total length of the plurality of longitudinal vibration portions,
An ultrasonic motor, wherein the moving object is moved in a predetermined direction by the expansion and contraction vibration of the longitudinal vibration portion and the bending vibration of the bending vibration portion being combined to generate an elliptical motion in the prefix member. Is provided.
[0020]
According to a ninth aspect of the present invention, a first structure having at least a first drive unit and a second drive unit having a substantially rectangular shape and having substantially the same shape in the longitudinal direction thereof A third drive unit having substantially the same length as the first structure, having a thickness shorter than the width of the first structure, and having substantially the same shape in the longitudinal direction. And a second structure having at least four drive units arranged side by side, wherein the first drive unit and the fourth drive unit are positioned diagonally, and the main structure of the first structure is A vibrator in which a side surface in the width direction of the second structure is aligned with a surface;
In the vibrator, the first drive unit and the fourth drive unit are expanded and contracted in the same phase, and the second drive unit and the third drive unit are in the same phase and substantially the same as the first drive unit. A prefix member disposed near an antinode of vibration generated by expanding and contracting at a phase shifted by 90 degrees and a holding member disposed near a node of the vibration;
Holding means for holding the holding member,
Pressing means for pressing the holding means against the moving body so that the prefix member is pressed against the moving body with a predetermined force;
An ultrasonic motor is provided, comprising:
[0021]
According to a tenth aspect of the present invention, a cylindrical piezoelectric ceramic member;
A common electrode provided on the inner peripheral surface of the piezoelectric ceramic member and used as a ground electrode,
A drive electrode provided in a predetermined pattern on the outer peripheral surface of the piezoelectric ceramic member so that an elliptical traveling wave is generated substantially at the center of the end surface of the piezoelectric ceramic member by applying an alternating voltage in an ultrasonic region,
A lid for closing an end face of the piezoelectric ceramic member,
A prefix member disposed substantially at the center of the lid,
Holding means for holding the piezoelectric ceramic member,
Pressing means for pressing the holding means against the moving body so that the prefix member is pressed against the moving body with a predetermined force;
An ultrasonic motor is provided, comprising:
[0022]
According to an eleventh aspect of the present invention, a cylindrical structure in which flat-plate-shaped piezoelectric ceramic rings and thin-film electrodes are alternately stacked,
A lid closing the end face of the cylindrical structure,
A prefix member disposed substantially at the center of the lid,
Holding means for holding the cylindrical structure,
Pressing means for pressing the holding means against the moving body so that the prefix member is pressed against the moving body with a predetermined force;
With
The electrode is
A drive electrode substantially equally divided into a predetermined number around the circumference of the piezoelectric ceramic ring,
A ring-shaped ground electrode having substantially the same shape as the main surface of the piezoelectric ceramic ring,
Has,
The drive electrodes are electrically connected to form a plurality of electrode groups,
An ultrasonic motor is provided, wherein an elliptical traveling wave is generated in the prefix member when an alternating voltage in an ultrasonic region is applied to the plurality of electrode groups.
[0023]
Since such an ultrasonic motor has a large driving force, a heavy object can be easily moved.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing a schematic structure of a vibrator 1 according to an embodiment of the present invention. FIG. 2 is a side view (FIG. 2A) showing a configuration of an ultrasonic motor 100 using the vibrator 1. It is sectional drawing (FIG.2 (b)).
[0025]
The vibrator 1 has a substantially rectangular shape, a longitudinal vibrating portion 2a that expands and contracts in the longitudinal direction (X direction), and a substantially rectangular shape having the same length as the length of the longitudinal vibrating portion 2a. A bending vibration portion 2b that bends and vibrates in the (Z direction) and an XY surface of the vertical vibration portion 2a (a surface perpendicular to the Z direction axis (a direction orthogonal to both the X direction and the Z direction is the Y direction)). And a holding member 7 provided on the XY plane of the bending vibration portion 2b for holding the bending vibration portion 2b, and a prefix member 6a holding the holding member 7 to hold the bending vibration portion 2b. -It has the pressing means 8 which presses 6b against the to-be-moved body 80, and the fixing means 9 which fixes the pressing means 8. Further, the ultrasonic motor 100 includes the vibrator 1, the moving body 80, and a guide rail (not shown) that holds the moving body 80 in a movable state in the X direction.
[0026]
In FIG. 1, the pressing means 8 and the fixing means 9 are not shown, and other vibrators other than the vibrator 1 described below are also used for the pressing means 8 and the fixing means 9 when they are illustrated. Are not shown.
[0027]
The vertical vibrating part 2a has a structure in which a plate-shaped piezoelectric element 4a is arranged on one of the ZX plane (a plane perpendicular to the Y-direction axis) of a rectangular structure 3a. For example, the piezoelectric element 4a can be bonded to the structure 3a using an adhesive. Further, the bending vibration portion 2b is provided with two plate-like piezoelectric elements 4b and 4c having substantially the same shape arranged in the X direction at a predetermined narrow interval on the XY plane of the rectangular structure 3b. It has the structure which was done. The vertical vibrating part 2a and the bending vibrating part 2b substantially constitute a vibrator, and the prefix members 6a and 6b efficiently move the vibrations generated in the vertical vibrating part 2a and the bending vibrating part 2b as described later. It is a member to be transmitted to the body 80.
[0028]
The structures 3a and 3b are made of a metal material such as aluminum or stainless steel. 1 and 2, the structure 3a and the structure 3b have an integrated structure having a substantially L-shaped cross section, but the structure 3a and the structure 3b are bonded with an adhesive, or They may be joined by welding. Note that an insulator can be used as the structures 3a and 3b as described later.
[0029]
Each of the piezoelectric elements 4a to 4c has a structure in which electrodes are provided on the front and back surfaces of a piezoelectric ceramic plate. FIG. 1 does not show the piezoelectric ceramic plate and the electrodes separately. The direction of polarization of the piezoelectric ceramic plate of the piezoelectric element 4a is the direction of + Y (arrow P 1 ). The direction of polarization of the piezoelectric ceramic plate of the piezoelectric element 4b is + Z (arrow P 2 ), The direction of polarization of the piezoelectric ceramic plate of the piezoelectric element 4c is -Z (arrow P). 3 ). The surface electrodes of the piezoelectric element 4b and the piezoelectric element 4c are electrically connected.
[0030]
The back electrode of the piezoelectric element 4a is electrically connected to the structure 3a, and the back electrodes of the piezoelectric elements 4b and 4c are electrically connected to the structure 3b. Since the structures 3a and 3b are integrally made of a metal material, as a result, the structures 3a and 3b can be used as a common electrode (earth electrode) when driving the piezoelectric elements 4a to 4c. .
[0031]
For example, the voltage V = V is applied to the surface electrode of the piezoelectric element 4a. 0 cosωt (V 0 : Rated voltage, ω: frequency, t: time), the d of the piezoelectric element 4a is applied to the longitudinal vibration portion 2a. 31 A stretching vibration occurs in the X direction due to the piezoelectric effect of the mode (longitudinal vibration mode). Further, a voltage V = V which is 90 degrees out of phase with the voltage applied to the surface electrodes of the piezoelectric elements 4b and 4c with respect to the voltage applied to the surface electrodes of the piezoelectric elements 4a. 0 When an AC voltage of sin ωt is applied, since the polarization directions of the piezoelectric ceramic plates of the piezoelectric elements 4b and 4c are reversed, d of the piezoelectric elements 4b and 4c is applied to the bending vibration portion 2b. 31 The bending vibration in the Z direction is generated by the piezoelectric effect of the mode and the clamping effect of the structure 3b (bending secondary vibration mode).
[0032]
By making the stretching vibration direction of the longitudinal vibration part 2a orthogonal to the bending vibration direction of the bending vibration part 2b, these stretching vibration and bending vibration are combined, and elliptical traveling waves are generated in the prefix members 6a and 6b. Since the prefix members 6a and 6b are pressed against the moving body 80 with a predetermined force by the pressing means 8, the moving body 80 moves in the -X direction or the + X direction by the force received from the prefix members 6a and 6b. I do. The directions of the elliptical traveling waves generated in the prefix members 6a and 6b can be changed by the phase difference between the voltage applied to the piezoelectric element 4a and the voltage applied to the piezoelectric elements 4b and 4c.
[0033]
In the bending vibration of the bending vibration part 2b, the central part in the X direction of the structure 3b is a node, and the central parts of the piezoelectric elements 4b and 4c in the X direction are antinodes. Therefore, as shown in FIGS. 1 and 2, the prefix members 6a and 6b are provided in the vicinity of a position corresponding to the antinode of the bending vibration of the bending vibration part 2b. This makes it possible to increase the amount of displacement of the prefix members 6a and 6b in the Z direction. Further, it is preferable that the holding member 7 is provided near a node of the bending vibration of the bending vibration portion 2b, that is, near the center in the X direction. Thus, the pressing means 8 and the holding member 7 are prevented from coming off due to vibration, and the vibrator 1 can be stably held.
[0034]
The prefix members 6a and 6b are made of a hard material such as a cemented carbide material or cast iron, or made of a wear-resistant ceramic material such as alumina, zirconia, silicon carbide or silicon nitride, or made of these materials. Those coated with titanium oxide or diamond are preferably used. The prefix members 6a and 6b may have an integral structure with the structure 3a. By making the tips of the prefix members 6a and 6b circular or spherical, wear can be reduced. As the object to be moved 80, an object to which a hard process such as a ladent process has been applied is suitably used.
[0035]
As the holding member 7, for example, a metal member having a columnar shape or a bolt shape can be used. Further, as the pressing means 8, an elastic mechanism such as a spring mechanism is used so that the head members 6a and 6b are pressed against the moving body 80 with a desired force. The pressing means 8 is attached to the holding member 7 according to the shape and material of the holding member 7, for example, by welding or mechanical connection such as bolting. Note that an air cylinder or the like can be used as the pressing means 8.
[0036]
In the vibrator 1, since the length (D2) of the bending vibration portion 2b in the Y direction (D2) is sufficiently larger than the length (D1) of the vertical vibration portion 2a in the Y direction, as shown in FIG. Increases. For example, in the ultrasonic motor 200 shown in FIG. 19, the ratio obtained by dividing the input admittance value of the bending vibration by the input admittance value of the longitudinal vibration is about 0.3. It can be set to 1.0. That is, in the ultrasonic motor 100, since the force generated by the bending vibration increases, the moving object 80 can be moved even if it is heavy. In order to realize an ultrasonic motor having a large driving force, the dimensions and the like of the components constituting the vibrator 1 are set so that the value of the input admittance in the bending vibration mode is 60% or more of the value of the input admittance in the longitudinal vibration mode. Is preferably designed.
[0037]
In the above-described vibrator 1, for example, the direction of polarization of the piezoelectric ceramic plate constituting the piezoelectric element 4c is changed by the arrow P in the same manner as the piezoelectric element 4b. 2 , And the surface electrode of the piezoelectric element 4b is not electrically connected to the surface electrode of the piezoelectric element 4c. In this case, for example, the voltage V = V is applied to the surface electrode of the piezoelectric element 4a. 0 When the AC voltage of cosωt is applied, the voltage V = V is applied to the surface electrode of the piezoelectric element 4b. 0 An AC voltage of sinωt is applied, and the voltage applied to the surface electrode of the piezoelectric element 4c is 180 ° out of phase with the voltage applied to the surface electrode of the piezoelectric element 4b, that is, the voltage V = −V 0 What is necessary is just to apply the AC voltage of sinωt.
[0038]
Further, as the structures 3a and 3b used in the vibrator 1, an insulating material (for example, engineering ceramics such as alumina, zirconia, and silicon nitride) can be used. In this case, since the structures 3a and 3b themselves cannot be used as ground electrodes, if the back electrodes of the piezoelectric elements 4a to 4c are taken out from the YZ plane (the plane perpendicular to the X-direction axis) of the structures 3a and 3b. Good. For example, if an electrode electrically connected to the surface of the structure 3a on which the piezoelectric element 4a is provided and the YZ surface of the structure 3a is provided, the ground electrode of the piezoelectric element 4a can be taken out of the YZ of the structure 3a. It can be easily performed from the surface. The structure 3b can have a similar structure.
[0039]
The vibrator 1 can be deformed like a vibrator 1A shown in the perspective view of FIG. The vibrator 1A shown in FIG. 4 and the vibrator 1 shown in FIG. 1 are different from each other in the configuration of the bending vibrating portion and the position and number of the prefix members. Specifically, in the vibrator 1A, a longitudinal vibration portion 2a having a piezoelectric element 4a and three piezoelectric elements 4d, 4e, and 4f having substantially the same shape on a surface of a structural body 3b have a predetermined narrow interval. And a bending vibration portion 2b 'arranged side by side in the X direction.
[0040]
In the bending vibration part 2b ', the direction of polarization of the piezoelectric ceramic plates constituting the piezoelectric elements 4d and 4f is the direction of + Z (arrow P). 2 ), The direction of polarization of the piezoelectric ceramic plate constituting the piezoelectric element 4e is -Z (arrow P 3 ), The surface electrodes of the piezoelectric elements 4d to 4f are electrically connected to each other.
[0041]
The structures 3a and 3b made of a metal material are used as ground electrodes, and a voltage V = V is applied to the surface electrodes of the piezoelectric elements 4d to 4f. 0 When an AC voltage of sin.omega.t is applied, the center in the X direction of each of the piezoelectric elements 4d to 4f becomes an antinode, and the bending is made with the boundary between the piezoelectric element 4d and the piezoelectric element 4e and the boundary between the piezoelectric element 4e and the piezoelectric element 4f as nodes. Vibration occurs. For this reason, the prefix members 6d to 6f that are in contact with the moving object (not shown) are arranged at positions corresponding to the antinodes of the bending vibration in the vertical vibration part 2a. In the bending vibration portion 2b ', a holding member 7a is provided between the piezoelectric element 4d and the piezoelectric element 4e which are nodes of the bending vibration, and a holding member 7b is provided at a position between the piezoelectric element 4e and the piezoelectric element 4f. Have been.
[0042]
Voltage V = V to piezoelectric elements 4d-4f 0 Simultaneously with the application of sinωt, a voltage V = V is applied to the surface electrode of the piezoelectric element 4a. 0 When an AC voltage of cos ωt is applied, an elliptical traveling wave having the same phase is generated in the prefix members 6d and 6f, and an elliptical traveling wave 180 ° shifted from the prefix members 6d and 6f is generated in the prefix member 6e. Thus, the vibrator 1 </ b> A can move a moving object (not shown) in the X direction, similarly to the vibrator 1.
[0043]
Note that the number of piezoelectric elements included in the bending vibration portion 2b 'may be four or more. In accordance with the number of piezoelectric elements provided in the structure 3b, the prefix member is disposed at a position corresponding to the center of each piezoelectric element in the X direction in the longitudinal vibration portion 2a, and the holding member is disposed between the piezoelectric elements. do it. When the surface electrodes of the respective piezoelectric elements are connected by wires, the respective piezoelectric elements are arranged so that the directions of polarization of the piezoelectric ceramic plates constituting the respective piezoelectric elements are alternated.
[0044]
Next, another embodiment of the present invention will be described. FIG. 5 is a perspective view showing a schematic structure of the vibrator 10. The vibrator 10 is an example of a mode in which a piezoelectric ceramic plate is used as the structures 3a and 3b constituting the vibrator 1 shown in FIG.
[0045]
The vibrator 10 has an arrow P 4 A vertical vibrating portion 12a having a drive electrode 14a and a ground electrode 14b provided on a ZX surface of a rectangular piezoelectric ceramic plate 13a polarized in the direction of + Y, represented by 5 The drive electrodes 14c and 14d which are approximately equally divided in the X direction are formed on one surface of the XY surface of the rectangular piezoelectric ceramic plate 13b polarized in the + Z direction represented by And a bending vibration portion 12b on which the ground electrode 14e is entirely formed. An insulating plate 19 is provided between the vertical vibration portion 12a and the bending vibration portion 12b.
[0046]
The insulating plate 19 prevents contact between the drive electrode 14a and the ground electrode 14b of the longitudinal vibrating portion 12a and the ground electrode 14e of the bending vibrating portion 12b, and also causes dielectric breakdown in a portion where the drive electrode 14a and the ground electrode 14e are close to each other. And functions as a clamp for causing the bending vibration portion 12b to generate bending vibration. Note that the piezoelectric ceramic plates 13a and 13b and the insulating plate 19 can be bonded with an epoxy resin adhesive or the like. As the insulating plate 19, a ceramic member such as alumina is preferably used.
[0047]
In the vibrator 10 having such a structure, for example, a voltage V = V is applied to the drive electrode 14a. 0 At the same time as applying the AC voltage of cos ωt, the voltage V = V 0 An AC voltage of sinωt is applied, and the voltage applied to the drive electrode 14d is 180 ° out of phase with the voltage applied to the drive electrode 14c, that is, the voltage V = −V 0 What is necessary is just to apply the AC voltage of sinωt. Thus, in the bending vibration portion 12b, the central portion in the X direction (between the drive electrode 14c and the drive electrode 14d) of the piezoelectric ceramic plate 13b is a node, and the central portions of the drive electrodes 14c and 14d in the X direction are antinodes. Flexural vibration occurs. The disposition positions of the holding member 7 and the prefix members 6a and 6b are determined in the same manner as in the case of the vibrator 1.
[0048]
Also in the vibrator 10, since the length of the bending vibration portion 12b in the Y direction is sufficiently longer than the length of the vertical vibration portion 12a in the Y direction, the force generated by the bending vibration increases, and an ultrasonic motor having a large driving force is realized. Is done.
[0049]
The vibrator 10 has a structure in which a piezoelectric ceramic plate 13a and a piezoelectric ceramic plate 13b are bonded to each other, and an ultrasonic motor using a piezoelectric ceramic member having a substantially L-shaped cross section having an integrated structure. May be configured. FIG. 6 is a schematic perspective view of a vibrator 10A including a piezoelectric ceramic member 18 including a vertical plate portion 18a and a horizontal plate portion 18b. The drive electrode 14a and the ground electrode 14b are formed on the ZX plane of the vertical plate portion 18a of the piezoelectric ceramic member 18 having the L-shaped cross section to form the vertical vibrating portion 12a ', and the horizontal plate portion 18b of the piezoelectric ceramic member 18 is formed. The drive electrodes 14c and 14d and the ground electrode 14e are formed on the XY plane, respectively, to form the bending vibration portion 12b '. The arrangement position of the prefix members 6a and 6b, the arrangement position of the holding member 7, and the driving method of the vibrator 10A in the vibrator 10A are the same as those of the vibrator 10, so that the detailed description is omitted here.
[0050]
FIG. 7 is a perspective view showing a schematic structure of a vibrator 20A which is still another embodiment according to the present invention. This vibrator 20A has a laminated structure of the piezoelectric ceramic member 18 constituting the vibrator 10A shown in FIG. That is, the vibrator 20A includes a vertical vibrating portion 21a in which a piezoelectric ceramic thin plate 22a and a drive electrode 23a / ground electrode 23b are laminated alternately in principle, a piezoelectric ceramic thin plate 22b and drive electrodes 23c and 23d / ground electrode 23e. And a bending vibration part 21b which is alternately laminated.
[0051]
In the longitudinal vibration section 21a, the drive electrode 23a and the ground electrode 23b are arranged every other layer, and the drive electrodes 23a are electrically connected to each other, and the ground electrodes 23b are electrically connected to each other. In the bending vibration portion 21b, the drive electrodes 23c and 23d are arranged separately in the X direction on the same XY plane, and the drive electrodes 23c and 23d and the ground electrode 23e are arranged every other layer. Are electrically connected, the drive electrodes 23d are electrically connected to each other, and the ground electrodes 23e are electrically connected to each other. The ground electrodes 23b and 23e may be electrically connected to each other.
[0052]
The polarization processing of the piezoelectric ceramic thin plate 22a is performed between the drive electrode 23a and the ground electrode 23b so that the drive electrode 23a side has a high potential. The polarization of the piezoelectric ceramic thin plate 22b is performed between the drive electrodes 23c and 23d and the ground electrode 23e so that the drive electrodes 23c and 23d have a high potential. In the longitudinal vibration section 21a, a piezoelectric inactive layer sandwiched between the ground electrode 23b and the ground electrode 23e is formed on the bending vibration section 21b side, and this piezoelectric inactive layer causes the bending vibration section 21b to generate bending vibration. Function as a clamping layer for
[0053]
The arrangement positions of the holding member 7 and the prefix members 6a and 6b in the vibrator 20A are determined in the same manner as the vibrator 10A. The driving method of the vibrator 20A is, for example, the same as that of the vibrator 10A (that is, the same as the vibrator 10). 0 cosωt is applied, and at the same time, the voltage V = V is applied to the surface electrode of the drive electrode 23c. 0 An AC voltage of sinωt is applied, and the voltage applied to the drive electrode 23d is 180 ° out of phase with the voltage applied to the drive electrode 23c, that is, the voltage V = −V 0 A method of applying an AC voltage of sinωt can be used. In the vibrator 20A, the driving voltage can be reduced by using the piezoelectric ceramic thin plates 22a and 22b.
[0054]
The vibrator 20A can be preferably manufactured by an integral firing method (simultaneous firing method) using a green sheet obtained by forming a sheet of piezoelectric ceramic powder. FIG. 8 is an explanatory diagram showing the form of the green sheet to be used. A green sheet 25a on which an electrode pattern serving as the drive electrode 23a is printed and a green sheet 25b on which an electrode pattern serving as the ground electrode 23b are alternately laminated, and a green sheet having no electrode pattern formed in the upper stage Stack several 25c. The green sheets 26a on which the electrode patterns serving as the drive electrodes 23c and 23d are printed and the green sheets 26b on which the electrode patterns serving as the ground electrodes 23e are printed are alternately stacked thereon. The green sheets 25a, 25b, 26a, and 26b are integrated by hot pressing and fired at a predetermined temperature. The YZ plane and ZX plane obtained in this way are subjected to a grinding treatment as required, and the same type of electrode is connected every other layer. In order to facilitate connection of the same type of electrodes, for example, the electrode pattern printed on the green sheet may be a multilayer capacitor type pattern.
[0055]
FIG. 9 is a perspective view showing a schematic structure of a vibrator 30A which is still another embodiment according to the present invention. The vibrator 30A has a configuration in which an L-shaped piezoelectric ceramic thin plate 32 and drive electrodes 33a / 33b / ground electrodes 33c are stacked alternately in principle in the X direction, and has a rectangular shape having a short length in the Y direction. The portion becomes a vertical vibration portion 31a that expands and contracts in the X direction, and the rectangular portion having a long length in the Y direction becomes a bending vibration portion 31b that bends in the Z direction. A piezoelectrically inactive region sandwiched between ground electrodes 33c is provided at the center of the vibrator 30A in the X direction, and a piezoelectric vibrating portion 31b side of the vertical vibrating portion 31a has a piezoelectric extending in the X direction. An inactive region is formed.
[0056]
The disposition positions of the holding member 7 and the prefix members 6a and 6b in the vibrator 30A are determined similarly to the vibrator 10A. All the drive electrodes 33a are connected to each other, and for example, a voltage V = V 0 An AC voltage of cosωt is applied. Further, the driving electrodes 33b located on the −X side from the holding member 7 are connected to each other, and the voltage V = −V 0 An AC voltage of sinωt is applied. The driving electrodes 33b located on the + X side from the holding member 7 are connected to each other. 0 An AC voltage of sinωt is applied. All the ground electrodes 33c have substantially the same shape as the piezoelectric ceramic thin plate 32, and are electrically connected between the longitudinal vibration portion 31a and the bending vibration portion 31b in each layer, and all the ground electrodes 33c are electrically connected to each other. Is done.
[0057]
As described above, the vibrator 30A also has the laminated structure of the piezoelectric ceramic member 18 constituting the vibrator 10A shown in FIG. The vibrator 30A has a piezoelectric ceramic member 18 having a laminated structure in the X direction, whereas the vibrator 30A has a laminated structure in the X direction. Accordingly, the vibrator 20A is formed on the piezoelectric ceramic thin plates 22a and 22b. 31 An elliptical traveling wave is generated in the prefix members 6a and 6b using the expansion and contraction displacement of the mode, but in the vibrator 30A, d is generated in the piezoelectric ceramic thin plate 32. 33 By utilizing the expansion and contraction displacement in the mode, the expansion and contraction vibration in the X direction is generated in the vertical vibration part 31a, and the bending vibration in the Z direction is generated in the bending vibration part 31b.
[0058]
FIG. 10 is a perspective view showing a schematic structure of a vibrator 40 as still another embodiment according to the present invention. The vibrator 40 has a configuration in which the substantially L-shaped structures 3a and 3b constituting the vibrator 1 shown in FIG. 1 are deformed into a substantially T-shape.
[0059]
That is, the vibrator 40 has a configuration in which the rectangular plate-like piezoelectric elements 43a and 43b are disposed on the ZX plane of the rectangular structure 42a, and the piezoelectric elements 43a and 43b are expanded and contracted at the same timing. 31 A longitudinal vibration portion 41a in which expansion and contraction vibration in the X direction is generated by driving in the mode, and two rectangular plate-like members having substantially the same shape on the XY plane of a rectangular structure 42b having the same length as the structure 42a. The piezoelectric elements 43c and 43d are arranged side by side in the X direction and are arranged at a predetermined narrow interval. 31 And a bending vibration section 41b that generates bending vibration in the Z direction by driving in the mode. The structures 42a and 42b are configured such that the length of the structure 42a in the Y direction is shorter than the length of the structure 42b in the Y direction, and these are joined so that the YZ plane is T-shaped.
[0060]
The piezoelectric element 43a is disposed on the structure 42a such that the direction of polarization of the piezoelectric ceramic plate constituting the piezoelectric element 43a is the + Y direction (arrow P 1 The piezoelectric element 43b is disposed on the structure 42a such that the direction of polarization of the piezoelectric ceramic plate constituting the piezoelectric element 43b is the -Y direction (arrow -P). 1 ). The surface electrodes of the piezoelectric elements 43a and 43b are electrically connected. The piezoelectric element 43c is disposed on the structure 42b such that the direction of polarization of the piezoelectric ceramic plate constituting the piezoelectric element 43c is the + Z direction (arrow P). 2 ), The piezoelectric element 43d is arranged on the structure 42b such that the direction of polarization of the piezoelectric ceramic plate constituting the piezoelectric element 43d is the -Z direction (arrow P). 3 ). The surface electrodes of the piezoelectric elements 43c and 43d are electrically connected. The structures 42a and 42b are used as ground electrodes.
[0061]
The arrangement positions of the prefix members 6a and 6b and the holding member 7 in the vibrator 40 are determined in the same manner as in the vibrator 1. Since the driving method of the vibrator 40 is the same as that of the vibrator 1 shown in FIG. 1, detailed description is omitted here.
[0062]
FIG. 11 is a perspective view showing a schematic structure of a vibrator 50 which is still another embodiment according to the present invention. In the vibrator 50, a rectangular plate-shaped piezoelectric element 53a is disposed on a ZX plane of a rectangular structure 52a, and the piezoelectric element 53a is set to d. 31 A first longitudinal vibrating portion 51a that generates expansion and contraction vibration in the X direction by driving in the mode, a second longitudinal vibrating portion 51a ′ having substantially the same structure as the longitudinal vibrating portion 51a, and the same length as the structure 52a. In this configuration, two rectangular plate-shaped piezoelectric elements 53c and 53d having substantially the same shape are arranged on the XY plane of the substantially rectangular structure 52c at a predetermined narrow interval in the X direction. Then, the piezoelectric elements 53c and 53d are inverted in timing of expansion and contraction to obtain d. 31 And a bending vibration section 51b that generates bending vibration in the Z direction by driving in the mode.
[0063]
The second vertical vibrating portion 51a 'has a structure in which a rectangular plate-shaped piezoelectric element 53b is provided on the ZX plane of a rectangular structure 52b. 31 By driving in the mode, stretching vibration in the X direction is generated in the second longitudinal vibration portion 51a '. The piezoelectric elements 53a and 53b are driven at the timing of expansion and contraction.
[0064]
In the vibrator 50, in order to increase the force generated by the bending vibrating portion 51b, the total length of the structures 52a and 52b in the Y direction is shorter than the length of the structure 52c in the Y direction. Are joined so that the shape of the YZ cross-section becomes substantially a 型 shape. The method of driving the vibrator 50 is the same as that of the vibrator 40 shown in FIG. 10, and a detailed description thereof will be omitted. The vibrator 50 may have a configuration in which the structural bodies 52a and 52b are sandwiched between two piezoelectric elements, similarly to the longitudinal vibrating portion 41a of the vibrator 40.
[0065]
FIG. 12A is a side view showing a schematic structure of a vibrator 60A as still another embodiment according to the present invention, and FIG. 12B is a sectional view taken along line AA shown in the side view of FIG. 12 (c) is a cross-sectional view taken along line BB shown in the side view of FIG. 12 (a). The vibrator 60A has a cylindrical shape of a piezoelectric ceramic tube 61, and is divided into approximately four equal parts around the periphery of the piezoelectric ceramic tube 61, and only a pair of electrodes facing each other in the radial direction are substantially two in the longitudinal direction (Z direction). The drive electrodes 62a, 62b, 62c, 62d, 62e, and 62f are formed by equally dividing, the ground electrode 62g formed on the entire inner peripheral surface of the piezoelectric ceramic tube 61, and one end surface of the piezoelectric ceramic tube 61. It has a cap 63 attached and a prefix member 64 provided at the center of the cap 63. Note that the cap 63 and the prefix member 64 may be formed integrally.
[0066]
The piezoelectric ceramic tube 61 is radially polarized in the radial direction, and the drive electrodes 62a to 62d are connected so that the drive electrodes 62a and 62d are electrically connected and the drive electrodes 62b and 62c are electrically connected. , And are connected in the form of crossing (FIG. 12A). The drive electrodes 62e and 62f are electrically connected to each other (FIGS. 12B and 12C).
[0067]
In the vibrator 60A, for example, the voltage V = V is applied to the drive electrodes 62a and 62d. 0 An AC voltage of sinωt is applied, and at the same time, a voltage V = −V is applied to the drive electrodes 62b and 62c. 0 An AC voltage of sinωt is applied, and a voltage V = V is applied to the drive electrodes 62e and 62f. 0 An AC voltage of cos ωt is applied. The part where the drive electrodes 62a to 62d are arranged functions as a bending vibration part, and generates displacement in the Y direction. On the other hand, the portion where the drive electrodes 62e and 62f are arranged functions as a vertical vibrating portion, and a displacement in the Z direction is generated. As a result, it is possible to generate an elliptical traveling wave that draws an elliptical locus in the YZ plane at the end face of the piezoelectric ceramic tube 61. Therefore, when a moving object (not shown) is brought into contact with the prefix member 64 at a predetermined pressure, the moving object can be moved in the Y direction. In the vibrator 60A, the vibration nodes are formed between the drive electrodes 62a and 62d and between the drive electrodes 62b and 62c. Therefore, the vibrator 60A is held at this portion.
[0068]
FIG. 13A is a side view showing a schematic structure of a vibrator 70A which is still another embodiment according to the present invention. This vibrator 70A is obtained by deforming the vibrator 60A shown in FIG. 12 into a laminated structure. That is, the vibrator 70 </ b> A includes the columnar structure 71, the cap 63 attached to one end surface of the columnar structure 71, and the provided prefix member 64 provided at the center of the cap 63. ing. The columnar structure 71 has a piezoelectric ceramic ring 72 of a flat ring shape, drive electrodes 73a, 73b, 73c, 73d, and a ground electrode 73e. The piezoelectric ceramic ring 72 and the drive electrodes 73a to 73d / ground electrode 73e are basically alternately stacked in the thickness direction of the piezoelectric ceramic ring 72.
[0069]
FIG. 13B is a plan view showing an electrode pattern of the drive electrodes 73a to 73d, and FIG. 13C is a plan view showing an electrode pattern of the ground electrode 73c. Each of the drive electrodes 73a to 73d has a quarter-arc shape substantially equally divided into four in the radial direction, and the ground electrode 73c has a ring shape. All the ground electrodes 73e are electrically connected, and a piezoelectric ceramic ring 72a sandwiched between the ground electrodes 73e is provided at the center in the stacking direction (Z direction). The vibrator 70A can be held by the piezoelectric inactive piezoelectric ceramic ring 72a.
[0070]
The drive electrodes 73a are electrically connected to each other from the center in the Z direction to the cap 63 side. 0 An AC voltage of sinωt is applied. The drive electrodes 73a are electrically connected to each other at an end surface (hereinafter, referred to as an “open end”) where the cap 63 is not provided from the center in the Z direction, and a voltage V = −V is applied thereto. 0 An AC voltage of sinωt is applied. Similarly, the drive electrodes 73b are electrically connected to each other from the center in the Z direction to the cap 63 side, and the voltage V = −V 0 An AC voltage of sinωt is applied. The drive electrodes 73b are electrically connected to each other at the open end side from the center in the Z direction, and the voltage V = V 0 An AC voltage of sinωt is applied. Further, all the driving electrodes 73c and the driving electrodes 73d are electrically connected, and the voltage V = V 0 An AC voltage of cosωt is applied.
[0071]
Thus, in the columnar structure 71, the portion where the drive electrodes 73a and 73b are arranged becomes a bending vibration portion, and the portion where the drive electrodes 73c and 73d are arranged becomes a vertical vibration portion. An elliptical traveling wave that draws an elliptical trajectory can be generated.
[0072]
FIG. 14 is a perspective view showing a schematic structure of a vibrator 10B which is still another embodiment according to the present invention. This vibrator 10B can be said to be a modified example of the vibrator 10A previously shown in FIG. In the vibrator 10B, two drive electrodes 14a ′ and 14a ″ that are approximately equally divided in the X direction are formed on one of the ZX planes of the vertical plate portion 18a of the piezoelectric ceramic member 18 having an L-shaped cross section, and ZX A ground electrode 14b is formed on the entire other surface, and drive electrodes 14c and 14d and a ground electrode 14e are formed on the XY plane of the horizontal plate portion 18b, respectively. The electrode 14d is electrically connected, and the drive electrode 14a ″ and the drive electrode 14c are electrically connected.
[0073]
In the vibrator 10B, expansion and contraction vibration is generated between the portion where the drive electrode 14a 'is provided and the portion where the drive electrode 14d is provided, and the drive electrode 14a "is displaced from the timing of the expansion and contraction. Elliptical traveling waves are generated in the prefix members 6a and 6b by causing expansion and contraction vibrations between the portion where is disposed and the portion where the drive electrode 14c is disposed. The disposition positions of the member 7 and the prefix members 6a and 6b are determined similarly to the vibrator 10A.
[0074]
Therefore, as a method of driving the vibrator 10B, for example, a voltage V = V is applied to the drive electrodes 14a 'and 14d. 0 At the same time as applying the AC voltage of sinωt, the voltage V = V is applied to the drive electrodes 14a ″ and 14c. 0 A method of applying an AC voltage of cos ωt is used. Also in the vibrator 10B, since the generated force in the Z direction generated in the horizontal plate portion 18b is increased, an ultrasonic motor having a large driving force is realized.
[0075]
FIG. 15 is a perspective view showing a schematic structure of a vibrator 20B according to still another embodiment of the present invention. The vibrator 20B has a piezoelectric ceramic member 18 constituting the vibrator 10B shown in FIG. The vibrator 20B includes a first laminated portion 27a in which piezoelectric ceramic thin plates 28a and drive electrodes 29a and 29b / ground electrodes 29c are alternately laminated in principle, a piezoelectric ceramic thin plate 28b and drive electrodes 29d and 29e / ground electrodes 29f. And a second stacked portion 27b in which the layers are alternately stacked. In the first stacked unit 27a, a piezoelectric inactive layer sandwiched between the ground electrode 29c and the ground electrode 29f is formed on the second stacked unit 27b side. The piezoelectric ceramic thin plate 28b is longer in the Y direction than the piezoelectric ceramic thin plate 28a.
[0076]
In the first laminated portion 27a, the drive electrodes 29a and 29b are arranged separately in the X direction on the same XY plane, and the drive electrodes 29a and 29b and the ground electrode 29c are arranged alternately. Similarly, in the second laminated portion 27b, the drive electrodes 29d and 29e are arranged separately in the X direction on the same XY plane, and the drive electrodes 29d and 29e and the ground electrode 29f are arranged alternately. The arrangement positions of the holding member 7 and the prefix members 6a and 6b in the vibrator 20B are determined in the same manner as the vibrator 10B.
[0077]
In order to cause the vibrator 20B to generate the same vibration as the vibrator 10B, for example, the drive electrodes 29a are electrically connected to each other and, for example, a voltage V = V 0 An AC voltage of sinωt is applied. Further, the drive electrodes 29b are electrically connected to each other, and a voltage V = V 0 An AC voltage of cos ωt is applied. Further, the drive electrodes 29d are electrically connected to each other, and a voltage V = V 0 An AC voltage of sinωt is applied. Furthermore, the drive electrodes 29e are connected to each other, and the voltage V = V 0 An AC voltage of cos ωt is applied. Thereby, an elliptical traveling wave can be generated in the prefix members 6a and 6b. Note that the vibrator 20B can be manufactured by the same method as the vibrator 20A described above. Such a laminated structure can be applied to a vibrator having a substantially T-shaped or substantially Π-shaped YZ plane.
[0078]
FIG. 16 is a perspective view showing a schematic structure of a vibrator 30B which is still another embodiment according to the present invention. A vibrator 30B shown in FIG. 16 is obtained by deforming the piezoelectric ceramic member 18 constituting the vibrator 10B shown in FIG. 14 so as to have a laminated structure in the X direction. That is, the vibrator 30B has a configuration in which the L-shaped piezoelectric ceramic thin plate 36 and the drive electrodes 37a and 37b / the ground electrode 37c are, in principle, alternately stacked in the X direction. Further, the arrangement positions of the holding member 7 and the prefix members 6a and 6b in the vibrator 30B are determined similarly to the vibrator 30A.
[0079]
All the ground electrodes 37c have substantially the same shape as the piezoelectric ceramic thin plate 36, and all the ground electrodes 37c are electrically connected to each other. Of the drive electrodes 37a, those located on the -X side from the position where the holding member 7 is disposed are electrically connected to each other. For example, a voltage V = V 0 An AC voltage of sinωt is applied. Further, among the drive electrodes 37b, those located on the −X side from the disposition position of the holding member 7 are electrically connected to each other, and the voltage V = V 0 An AC voltage of cosωt is applied. Further, among the drive electrodes 37a, those located on the + X side from the arrangement position of the holding member 7 are electrically connected to each other, and the voltage V = V 0 An AC voltage of cosωt is applied. Furthermore, of the drive electrodes 37b, those located on the + X side from the position where the holding member 7 is disposed are electrically connected to each other, and the voltage V = V 0 An AC voltage of sinωt is applied.
[0080]
Thus, in the vibrator 30B, d generated on the piezoelectric ceramic thin plate 36 33 By using the expansion and contraction displacement of the mode, an elliptical traveling wave can be generated in the prefix members 6a and 6b. The vibrator 30B can be manufactured by the same method as the vibrator 20A described above. Such a laminated structure can be applied to a vibrator having a substantially T-shaped or substantially Π-shaped YZ plane.
[0081]
FIG. 17A is a side view showing a schematic structure of a vibrator 60B according to still another embodiment of the present invention, and FIG. 17B is a sectional view taken along the line AA in FIG. ) Is a BB cross-sectional view in the side view. The vibrator 60B is formed by dividing a piezoelectric ceramic tube 61 having a cylindrical shape into approximately two equal parts in the longitudinal direction (Z direction) on the outer peripheral surface of the piezoelectric ceramic tube 61 and substantially equally dividing the circumference. Drive electrodes 67 a, 67 b, 67 c, 67 d, a ground electrode 67 e formed on the entire inner peripheral surface of the piezoelectric ceramic tube 61, a cap 63 disposed on one end surface of the piezoelectric ceramic tube 61, and a cap 63. And a prefix member 64 provided at the center of the head.
[0082]
The piezoelectric ceramic tube 61 is radially polarized in a radial direction, for example, by applying a high voltage between the ground electrode 67e and the drive electrodes 67a to 67d. The drive electrodes 67a to 67d are connected in a crossing manner so that the drive electrodes 67a and 67d are electrically connected to each other and the drive electrodes 67b and 67c are electrically connected to each other.
[0083]
In the vibrator 60B, for example, the voltage V = V is applied to the drive electrodes 67a and 67d. 0 An AC voltage of cos ωt is applied, and a voltage V = V is applied to the drive electrodes 67b and 67c. 0 By applying an AC voltage of sin ωt, it is possible to generate an elliptical traveling wave that draws an elliptical trajectory in the YZ plane at the end face of the piezoelectric ceramic tube 61. The direction of movement of the moving object can be determined by changing the phase of the voltage applied to the driving electrodes 67a and 67d and the phase of the voltage applied to the driving electrodes 67b and 67c. In the vibrator 60B, the central portion in the Z direction is a node of vibration, and the vibrator 60B is held at this portion.
[0084]
FIG. 18A is a side view showing a schematic structure of a vibrator 70B as still another embodiment according to the present invention. The vibrator 70B is obtained by deforming the vibrator 60B shown in FIG. 17 into a laminated structure. That is, the vibrator 70 </ b> B includes the columnar structure 75, the cap 63 attached to one end surface of the columnar structure 75, and the prefix member 64 provided at the center of the cap 63. ing. The columnar structure 75 has a flat-plate-shaped piezoelectric ceramic ring 76, drive electrodes 77a and 77b, and a ground electrode 77c. The piezoelectric ceramic ring 76 and the drive electrodes 77a and 77b / ground electrode 77c It has a structure in which the piezoelectric ceramic rings 76 are stacked alternately in the thickness direction in principle.
[0085]
FIG. 18B is a plan view showing an electrode pattern of the drive electrodes 77a and 77b, and FIG. 18C is a plan view showing an electrode pattern of the ground electrode 77c. The drive electrodes 77a and 77b have a semicircular shape that is approximately equally divided in the radial direction, and the ground electrode 77c has a ring shape. All the ground electrodes 77c are electrically connected, and a piezoelectric ceramic ring 76a sandwiched between the ground electrodes 77c is provided at the center in the stacking direction (Z direction). The vibrator 70B can be held by the piezoelectric inactive piezoelectric ceramic ring 76a.
[0086]
The drive electrodes 77a are electrically connected to each other from the center in the Z direction on the cap 63 side, for example, when the voltage V = V 0 An AC voltage of sinωt is applied. The drive electrodes 77a are electrically connected to each other from the center in the Z direction to the open end, and the drive electrode 77a is connected to the drive electrode 77a by the voltage V = V 0 An AC voltage of cosωt is applied. Similarly, the drive electrodes 77b are electrically connected to each other from the center in the Z direction on the cap 63 side, and the voltage V = V 0 An AC voltage of cosωt is applied. The drive electrodes 77b are electrically connected to each other at the open end side from the center in the Z direction, and the voltage V = V 0 An AC voltage of sinωt is applied. Thus, an elliptical traveling wave that draws an elliptical locus in the YZ plane can be generated in the prefix member 64.
[0087]
The embodiment of the present invention has been described above, but the present invention is not limited to such an embodiment. Although the sine wave and the cosine wave are mentioned as the driving voltage waveforms of the vibrator 1 and the like, a triangular wave or a rectangular pulse wave may be used instead. Further, as an example of generating an elliptical traveling wave on the prefix members 6a and 6b of the vibrator 1, for example, a voltage V = V 0 cosωt is applied to the surface electrodes of the piezoelectric elements 4b and 4c by the voltage V = V 0 Although the case where sinωt is applied has been described, the phase difference between the voltage applied to the surface electrodes of the piezoelectric elements 4a and the voltages applied to the surface electrodes of the piezoelectric elements 4b and 4c does not need to be completely 90 degrees. The phase difference may be shifted from 90 degrees as long as the body 80 can be moved.
[0088]
Further, for example, by connecting a plurality of transducers 1 in the Y direction, an ultrasonic motor having a larger driving force can be realized. In the above description, the configuration in which the prefix member is disposed in the vertical vibration section and the holding member is disposed in the bending vibration section has been described. Conversely, the prefix member is disposed in the bending vibration section, and the holding member is vertically positioned. It can also be arranged on the vibrating part. In this case, since the prefix member comes into contact with the drive electrode, an insulator (for example, insulating ceramics or the like) is preferably used as the prefix member material. The moving object is not limited to the slider that moves in the linear direction, and may be a rotating body.
[0089]
Further, the vibrator 40 shown in FIG. 10 and the vibrator 50 shown in FIG. 11 can be modified into a configuration using a T-shaped or Π-shaped piezoelectric ceramic member. Needless to say, it is possible to form a laminated structure. In the vibrator 50, when the bending vibration part 51b is a bottom wall and the vertical vibration parts 51a and 51a 'are side walls, it is possible to use the vibrator 50 for the purpose of flowing a component or a fluid into a groove surrounded by these parts. Such a method of use can be similarly applied to the vibrator 60A having a cylindrical shape.
[0090]
【The invention's effect】
As described above, according to the vibrator and the ultrasonic motor of the present invention, since the driving force is large, for example, there is an effect that a heavy object can be conveyed.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view showing an embodiment of a vibrator according to the present invention.
2A and 2B are a side view and a cross-sectional view illustrating a schematic configuration of an ultrasonic motor using the transducer illustrated in FIG.
FIG. 3 is an explanatory diagram showing input admittance characteristics of the vibrator shown in FIG. 1;
FIG. 4 is a schematic perspective view showing another embodiment of the vibrator according to the present invention.
FIG. 5 is a schematic perspective view showing still another embodiment of the vibrator according to the present invention.
FIG. 6 is a schematic perspective view showing still another embodiment of the vibrator according to the present invention.
FIG. 7 is a schematic perspective view showing still another embodiment of the vibrator according to the present invention.
FIG. 8 is an explanatory view showing a configuration of a green sheet used for manufacturing the vibrator shown in FIG.
FIG. 9 is a schematic perspective view showing still another embodiment of the vibrator according to the present invention.
FIG. 10 is a schematic perspective view showing still another embodiment of the vibrator according to the present invention.
FIG. 11 is a schematic perspective view showing still another embodiment of the vibrator according to the present invention.
FIG. 12 is a schematic side view and a sectional view showing still another embodiment of the vibrator according to the present invention.
FIG. 13 is a schematic side view showing still another embodiment of the vibrator according to the present invention, and a plan view of a drive electrode and a ground electrode constituting the vibrator.
FIG. 14 is a schematic perspective view showing still another embodiment of the vibrator according to the present invention.
FIG. 15 is a schematic perspective view showing still another embodiment of the vibrator according to the present invention.
FIG. 16 is a schematic perspective view showing still another embodiment of the vibrator according to the present invention.
FIG. 17 is a schematic side view and a sectional view showing still another embodiment of the vibrator according to the present invention.
FIG. 18 is a schematic side view showing still another embodiment of the vibrator according to the present invention, and a plan view of a drive electrode and a ground electrode constituting the vibrator.
FIG. 19 is an explanatory view showing a schematic configuration of a conventional ultrasonic motor.
20 is an explanatory diagram showing input admittance characteristics of the ultrasonic motor shown in FIG.
[Explanation of symbols]
1.1A; vibrator, 2a; longitudinal vibrating part, 2b; bending vibrating part, 3a, 3b; structure, 4a to 4f; piezoelectric element, 6a, 6b, 6d to 6f; prefix member, 7, 7a, 7b; Holding member, 8; pressing means, 9; fixing means, 10 · 10A · 10B; vibrator, 12a · 12a ′; longitudinal vibrating part, 12b · 12b ′; bending vibrating part, 13a · 13b; piezoelectric ceramic plate, 14a · 14a ', 14a ", 14c, 14d, 14', 14"; drive electrode, 14b, 14e; ground electrode, 18; piezoelectric ceramic member, 18a; vertical plate, 18b; horizontal plate, 19; insulating plate, 20A 20B; vibrator, 21a; longitudinal vibrator, 21b; bending vibrator, 22a, 22b; piezoelectric ceramic thin plate, 23a, 23c, 23d; drive electrode, 23b, 23e; ground electrode, 25a, 25b, 25c, 26a. 26b Green sheet, 27a; first laminated portion, 27b; second laminated portion, 28a, 28b; piezoelectric ceramic thin plate, 29a, 29b, 29d, 29e; drive electrode, 29c, 29f; ground electrode, 30A, 30B; 31a; longitudinal vibrating part, 31b; bending vibrating part, 32; piezoelectric ceramic thin plate, 33a, 33b; drive electrode, 33c; ground electrode, 36 piezoelectric ceramic thin plate, 37a, 37b; drive electrode, 37c, ground electrode, 40; Vibrator, 41a; longitudinal vibrator, 41b; flexural vibrator, 42a, 42b; structure, 43a to 43d; piezoelectric element, 50; vibrator, 51a, 51a '; longitudinal vibrator, 51b; flexural vibrator, 52a 52b, 52c; structure, 53a to 53d; piezoelectric element, 60A, 60B; vibrator, 61; piezoelectric ceramic tube, 62a to 62f; drive electrode, 62g Ground electrode, 63; cap, 64; prefix member, 67a to 67d; drive electrode, 67e; ground electrode, 70A / 70B; vibrator, 71; columnar structure, 72 / 72a; piezoelectric ceramic ring, 73a to 73d; Electrode, 73e; ground electrode, 75; columnar structure, 76; piezoelectric ceramic ring, 77a / 77b; drive electrode, 77c; ground electrode, 80; moving object, 100: ultrasonic motor, 200; ultrasonic motor, 201 Piezoelectric plate, 202; prefix member, 203; first holding member, 204; second holding member, 205a to 205d; split electrode, 210;

Claims (21)

略矩形の形状を有し、その長手方向に伸縮振動する縦振動部と、
前記縦振動部と略同一長さの略矩形形状を有し、その厚み方向に屈曲振動する屈曲振動部と、
を具備する振動子であって、
前記縦振動部の伸縮振動方向と前記屈曲振動部の屈曲振動方向が直交し、かつ、前記縦振動部の長手方向と前記屈曲振動部の長手方向が一致し、
前記屈曲振動方向と前記伸縮振動方向とに直交する方向における、屈曲振動部の長さが前記縦振動部の長さよりも長いことを特徴とする振動子。A longitudinal vibrating portion having a substantially rectangular shape and vibrating in the longitudinal direction thereof,
A bending vibration portion having a substantially rectangular shape having substantially the same length as the longitudinal vibration portion, and bending and vibrating in a thickness direction thereof,
A vibrator comprising:
The stretching vibration direction of the longitudinal vibration part and the bending vibration direction of the bending vibration part are orthogonal, and the longitudinal direction of the longitudinal vibration part and the longitudinal direction of the bending vibration part match,
A vibrator, wherein a length of the bending vibration portion in a direction orthogonal to the bending vibration direction and the stretching vibration direction is longer than a length of the longitudinal vibration portion. 前記縦振動部と前記屈曲振動部は、前記長手方向に垂直な面における断面形状が略Ｌ字型または略Ｔ字型となるように配置されていることを特徴とする請求項１に記載の振動子。The said vertical vibration part and the said bending vibration part are arrange | positioned so that the cross-sectional shape in the surface perpendicular | vertical to the said longitudinal direction may become substantially L-shaped or substantially T-shaped. Vibrator. 略矩形の形状を有し、所定間隔でその主面が平行となるように配置され、その長手方向に伸縮振動する複数の縦振動部と、
前記縦振動部の長さと略同一の長さの略矩形形状を有し、その厚み方向に屈曲振動する屈曲振動部と、
を具備する振動子であって、
前記縦振動部の伸縮振動方向と前記屈曲振動部の屈曲振動方向が直交し、かつ、前記縦振動部の長手方向と前記屈曲振動部の長手方向が一致し、
前記屈曲振動方向と前記伸縮振動方向とに直交する方向における、前記屈曲振動部の長さが前記複数の縦振動部の長さの合計長さよりも長いことを特徴とする振動子。A plurality of longitudinal vibrating portions having a substantially rectangular shape, arranged at predetermined intervals so that their main surfaces are parallel, and vibrating in the longitudinal direction thereof,
A bending vibration portion having a substantially rectangular shape having substantially the same length as the length of the vertical vibration portion, and bending and vibrating in its thickness direction;
A vibrator comprising:
The stretching vibration direction of the longitudinal vibration part and the bending vibration direction of the bending vibration part are orthogonal, and the longitudinal direction of the longitudinal vibration part and the longitudinal direction of the bending vibration part match,
A vibrator, wherein a length of the bending vibration portion in a direction orthogonal to the bending vibration direction and the stretching vibration direction is longer than a total length of the plurality of longitudinal vibration portions. 前記縦振動部は、第１の矩形構造体と、前記第１の矩形構造体の主面の一方または両方に配設された第１の板状圧電素子と、を具備し、
前記屈曲振動部は、第２の矩形構造体と、前記第２の矩形構造体の表面に配設された第２の板状圧電素子と、を具備することを特徴とする請求項１から請求項３のいずれか１項に記載の振動子。The longitudinal vibration unit includes a first rectangular structure, and a first plate-shaped piezoelectric element provided on one or both main surfaces of the first rectangular structure,
The said bending vibration part is provided with the 2nd rectangular structure and the 2nd plate-shaped piezoelectric element arrange | positioned at the surface of the 2nd rectangular structure, The claim 1 characterized by the above-mentioned. Item 4. The vibrator according to any one of items 3. 前記第１の矩形構造体と前記第２の矩形構造体は一体構造を有することを特徴とする請求項４に記載の振動子。The vibrator according to claim 4, wherein the first rectangular structure and the second rectangular structure have an integral structure. 前記縦振動部は、主面に電極が形成された略矩形の第１の圧電セラミック板からなり、
前記屈曲振動部は、主面に電極が形成された略矩形の第２の圧電セラミック板からなることを特徴とする請求項１から請求項３のいずれか１項に記載の振動子。The longitudinal vibrating portion is formed of a substantially rectangular first piezoelectric ceramic plate having an electrode formed on a main surface thereof,
4. The vibrator according to claim 1, wherein the bending vibration portion is formed of a substantially rectangular second piezoelectric ceramic plate having an electrode formed on a main surface. 5. 前記第１の圧電セラミック板と前記第２の圧電セラミック板は一体構造を有することを特徴とする請求項６に記載の振動子。The vibrator according to claim 6, wherein the first piezoelectric ceramic plate and the second piezoelectric ceramic plate have an integral structure. 前記縦振動部と前記屈曲振動部はそれぞれ、圧電セラミック薄板と電極とが前記屈曲振動部の屈曲振動方向または前記屈曲振動部の長手方向で交互に積層された構造を有することを特徴とする請求項１から請求項３のいずれか１項に記載の振動子。The longitudinal vibration section and the bending vibration section each have a structure in which a piezoelectric ceramic thin plate and an electrode are alternately stacked in the bending vibration direction of the bending vibration section or in the longitudinal direction of the bending vibration section. The vibrator according to any one of claims 1 to 3. 略矩形形状を有し、その長手方向に実質的に同一形状を有する第１の駆動部および第２の駆動部を少なくとも並べ備えた第１の構造体と、
前記第１の構造体と略同一長さを有し、その厚みが前記第１の構造体の幅よりも短く、その長手方向に実質的に同一形状を有する第３の駆動部および第４の駆動部を少なくとも並べ備えた第２の構造体と、
を具備する振動子であって、
前記第１の駆動部と前記第４の駆動部とが対角に位置するように、前記第１の構造体の主面に前記第２の構造体の幅方向の側面が接続され、
前記第１の駆動部と前記第４の駆動部を同位相で伸縮させ、前記第２の駆動部と前記第３の駆動部を同位相かつ前記第１の駆動部と略９０度ずれた位相で伸縮させることにより、前記第１位の構造体と前記第２の構造体の所定位置に楕円進行波が生ずることを特徴とする振動子。A first structure having a substantially rectangular shape and at least a first drive unit and a second drive unit having substantially the same shape in the longitudinal direction thereof;
A third drive unit and a fourth drive unit having substantially the same length as the first structure, having a thickness shorter than the width of the first structure, and having substantially the same shape in the longitudinal direction. A second structure having at least a drive unit,
A vibrator comprising:
A side surface in a width direction of the second structure is connected to a main surface of the first structure such that the first drive unit and the fourth drive unit are located diagonally,
The first drive unit and the fourth drive unit are expanded and contracted in phase, and the second drive unit and the third drive unit are in phase and shifted from the first drive unit by approximately 90 degrees. A vibrator characterized in that an elliptical traveling wave is generated at a predetermined position between the first structure and the second structure by expanding and contracting the first structure and the second structure. 略矩形の形状を有し、その長手方向に伸縮振動する縦振動部と、
前記縦振動部と略同一長さの略矩形形状を有し、その厚み方向に屈曲振動する屈曲振動部と、
を具備し、
前記縦振動部の伸縮振動方向と前記屈曲振動部の屈曲振動方向が直交し、かつ、前記縦振動部の長手方向と前記屈曲振動部の長手方向が一致している振動子であって、
前記屈曲振動部の入力アドミッタンスが、前記縦振動部の入力アドミッタンスの６０％以上であることを特徴とする振動子。A longitudinal vibrating portion having a substantially rectangular shape and vibrating in the longitudinal direction thereof,
A bending vibration portion having a substantially rectangular shape having substantially the same length as the longitudinal vibration portion, and bending and vibrating in a thickness direction thereof,
With
A vibrator in which a stretching vibration direction of the longitudinal vibration part and a bending vibration direction of the bending vibration part are orthogonal, and a longitudinal direction of the longitudinal vibration part and a longitudinal direction of the bending vibration part coincide with each other,
A vibrator, wherein an input admittance of the bending vibration section is 60% or more of an input admittance of the longitudinal vibration section. 円筒形の圧電セラミック部材と、
前記圧電セラミック部材の内周面に設けられ、接地電極として用いられる共通電極と、
超音波領域の交番電圧が印加されることによって前記圧電セラミック部材の端面の略中心部に楕円進行波が生ずるように、前記圧電セラミック部材の外周面に所定パターンで設けられた駆動電極と、
を具備することを特徴する振動子。A cylindrical piezoelectric ceramic member;
A common electrode provided on the inner peripheral surface of the piezoelectric ceramic member and used as a ground electrode,
A drive electrode provided in a predetermined pattern on the outer peripheral surface of the piezoelectric ceramic member so that an elliptical traveling wave is generated substantially at the center of the end surface of the piezoelectric ceramic member by applying an alternating voltage in an ultrasonic region,
A vibrator comprising: 前記駆動電極は、前記圧電セラミック部材の周回りで略２等分割され、かつ、長手方向で略２等分割されて形成される４個の電極要素を有し、
前記４個の電極要素は、たすき掛けして接続されることによって２組の電極群を構成していることを特徴とする請求項１１に記載の振動子。The drive electrode has four electrode elements formed by being divided into approximately two equal parts around the circumference of the piezoelectric ceramic member, and being substantially equally divided in the longitudinal direction,
The vibrator according to claim 11, wherein the four electrode elements form two sets of electrodes by being crossed and connected. 前記駆動電極は、前記圧電セラミック部材の周回りで略４等分割され、かつ、前記圧電セラミック部材の径方向で対向する２組の電極のうち１組の電極は前記圧電セラミック部材の長手方向で略２等分割されて形成される６個の電極要素を有し、
前記圧電セラミック部材の長手方向で略２等分割されてなる４個の電極要素はたすき掛けして接続されることによって２組の電極群を構成し、
前記圧電セラミック部材の長手方向で分割されていない２個の電極要素が互いに接続されることによって１組の電極群を構成していることを特徴とする請求項１１に記載の振動子。The drive electrode is divided into approximately four equal parts around the circumference of the piezoelectric ceramic member, and one of the two sets of electrodes that face each other in the radial direction of the piezoelectric ceramic member is arranged in the longitudinal direction of the piezoelectric ceramic member. It has six electrode elements formed by being divided into approximately two equal parts,
Four electrode elements, which are approximately equally divided in the longitudinal direction of the piezoelectric ceramic member, are crossed and connected to form two electrode groups,
The vibrator according to claim 11, wherein two electrode elements that are not divided in the longitudinal direction of the piezoelectric ceramic member are connected to each other to form a set of electrode groups. 平板リング状の圧電セラミックリングと電極とが交互に積層された円筒状構造体と、前記円筒状構造体の端面に配設された円板部材と、を有する振動子であって、
前記電極は、
前記圧電セラミックリングの円周回りに所定数に略等分割された駆動電極と、
前記圧電セラミックリングの主面と略同形状のリング状の接地電極と、
を有し、
前記駆動電極は、複数の電極群が構成されるように電気的に接続され、
前記複数の電極群に超音波領域の交番電圧が印加されることによって、前記円板部材の端面の略中心部に楕円進行波が生ずることを特徴とする振動子。A vibrator having a cylindrical structure in which plate-shaped piezoelectric ceramic rings and electrodes are alternately stacked, and a disk member disposed on an end surface of the cylindrical structure,
The electrode is
Drive electrodes substantially equally divided into a predetermined number around the circumference of the piezoelectric ceramic ring,
A ring-shaped ground electrode having substantially the same shape as the main surface of the piezoelectric ceramic ring,
Has,
The drive electrodes are electrically connected to form a plurality of electrode groups,
A vibrator characterized in that an elliptical traveling wave is generated at a substantially central portion of an end surface of the disk member by applying an alternating voltage in an ultrasonic region to the plurality of electrode groups. 前記駆動電極は周回りで略２等分割または略４等分割された電極要素を有することを特徴とする請求項１４に記載の振動子。The vibrator according to claim 14, wherein the drive electrode has electrode elements that are substantially equally divided or substantially equally divided around the circumference. 前記円筒状構造体は、前記圧電セラミックリングと前記電極の積層方向中央部に、前記接地電極に挟まれた圧電不活性な圧電セラミックリングを有することを特徴とする請求項１４または請求項１５に記載の振動子。The said cylindrical structure has the piezoelectric inactive piezoelectric ceramic ring pinched | interposed by the said ground electrode in the center part of the lamination direction of the said piezoelectric ceramic ring and the said electrode, The Claim 14 or Claim 15 characterized by the above-mentioned. The described oscillator. 略矩形の形状を有し、その長手方向に伸縮振動する縦振動部と、前記縦振動部と略同一長さの略矩形形状を有し、その厚み方向に屈曲振動する屈曲振動部とを具備し、前記縦振動部の伸縮振動方向と前記屈曲振動部の屈曲振動方向が直交し、かつ、前記縦振動部の長手方向と前記屈曲振動部の長手方向が一致している振動子と、
前記屈曲振動部の屈曲振動に起因して前記縦振動部に生ずる前記屈曲振動方向の振動の腹部の近傍に配設された接頭部材と、
前記屈曲振動部において前記屈曲振動部に生ずる屈曲振動の節部の近傍に配設された保持部材と、
前記保持部材を保持する保持手段と、
前記接頭部材が被移動体に所定の力で押し当てられるように前記保持手段を前記被移動体に押圧する押圧手段と、
を備え、
前記振動子において、前記屈曲振動方向と前記伸縮振動方向とに直交する方向における、屈曲振動部の長さが前記縦振動部の長さよりも長く、
前記縦振動部の伸縮振動と前記屈曲振動部の屈曲振動とが合わされて前記接頭部材に楕円運動が生ずることによって、前記被移動体を所定の方向に移動させることを特徴とする超音波モータ。It has a substantially vibrating part having a substantially rectangular shape and vibrating in the longitudinal direction thereof, and a bending vibrating part having a substantially rectangular shape having substantially the same length as the longitudinal vibrating part and bending and vibrating in the thickness direction. And a vibrator in which the stretching vibration direction of the longitudinal vibration part and the bending vibration direction of the bending vibration part are orthogonal, and the longitudinal direction of the longitudinal vibration part and the longitudinal direction of the bending vibration part match.
A prefix member disposed near an antinode of vibration in the bending vibration direction generated in the longitudinal vibration portion due to the bending vibration of the bending vibration portion,
A holding member disposed in the vicinity of a node of bending vibration generated in the bending vibration section in the bending vibration section;
Holding means for holding the holding member,
Pressing means for pressing the holding means against the moving body so that the prefix member is pressed against the moving body with a predetermined force;
With
In the vibrator, the length of the bending vibration portion in a direction orthogonal to the bending vibration direction and the stretching vibration direction is longer than the length of the longitudinal vibration portion,
An ultrasonic motor, wherein the object to be moved is moved in a predetermined direction by the expansion and contraction vibration of the longitudinal vibration part and the bending vibration of the bending vibration part being combined to generate an elliptical movement in the prefix member. 略矩形の形状を有し、所定間隔でその主面が平行となるように配置され、その長手方向に伸縮振動する複数の縦振動部と、前記縦振動部の長さと略同一の長さの略矩形形状を有し、その厚み方向に屈曲振動する屈曲振動部とを具備し、前記縦振動部の伸縮振動方向と前記屈曲振動部の屈曲振動方向とが直交し、かつ、前記縦振動部の長手方向と前記屈曲振動部の長手方向とが一致している振動子と、
前記屈曲振動部の屈曲振動に起因して前記縦振動部に生ずる前記屈曲振動方向の振動の腹部の近傍に配設された接頭部材と、
前記屈曲振動部において前記屈曲振動部に生ずる屈曲振動の節部の近傍に配設された保持部材と、
前記保持部材を保持する保持手段と、
前記接頭部材が被移動体に所定の力で押し当てられるように前記保持手段を前記被移動体に押圧する押圧手段と、
を備え、
前記振動子において、前記屈曲振動方向と前記伸縮振動方向とに直交する方向における、前記屈曲振動部の長さが前記複数の縦振動部の長さの合計長さよりも長く、
前記縦振動部の伸縮振動と前記屈曲振動部の屈曲振動とが合わされて前記接頭部材に楕円運動が生ずることによって、前記被移動体を所定の方向に移動させることを特徴とする超音波モータ。It has a substantially rectangular shape, is disposed so that its main surface is parallel at a predetermined interval, and a plurality of longitudinal vibrating portions that expand and contract in the longitudinal direction thereof, and have a length substantially the same as the length of the longitudinal vibrating portion. A bending vibration part having a substantially rectangular shape and bending and vibrating in the thickness direction thereof, wherein a stretching vibration direction of the longitudinal vibration part and a bending vibration direction of the bending vibration part are orthogonal to each other, and A vibrator in which the longitudinal direction of the bending vibration portion and the longitudinal direction are the same,
A prefix member disposed near an antinode of vibration in the bending vibration direction generated in the longitudinal vibration portion due to the bending vibration of the bending vibration portion,
A holding member disposed in the vicinity of a node of bending vibration generated in the bending vibration section in the bending vibration section;
Holding means for holding the holding member,
Pressing means for pressing the holding means against the moving body so that the prefix member is pressed against the moving body with a predetermined force;
With
In the vibrator, a length of the bending vibration portion in a direction orthogonal to the bending vibration direction and the stretching vibration direction is longer than a total length of the plurality of longitudinal vibration portions,
An ultrasonic motor, wherein the object to be moved is moved in a predetermined direction by the expansion and contraction vibration of the longitudinal vibration part and the bending vibration of the bending vibration part being combined to generate an elliptical movement in the prefix member. 略矩形形状を有し、その長手方向に実質的に同一形状を有する第１の駆動部および第２の駆動部を少なくとも並べ備えた第１の構造体と、前記第１の構造体と略同一長さを有し、その厚みが前記第１の構造体の幅よりも短く、その長手方向に実質的に同一形状を有する第３の駆動部および第４の駆動部を少なくとも並べ備えた第２の構造体とを具備し、前記第１の駆動部と前記第４の駆動部とが対角に位置し、かつ、前記第１の構造体の主面に前記第２の構造体の幅方向の側面が合わせされてなる振動子と、
前記振動子において、前記第１の駆動部と前記第４の駆動部を同位相で伸縮させ、前記第２の駆動部と前記第３の駆動部を同位相かつ前記第１の駆動部と略９０度ずれた位相で伸縮させることによって生ずる振動の腹の部分の近傍に配設された接頭部材および前記振動の節の部分の近傍に配置された保持部材と、
前記保持部材を保持する保持手段と、
前記接頭部材が被移動体に所定の力で押し当てられるように前記保持手段を前記被移動体に押圧する押圧手段と、
を備えていることを特徴とする超音波モータ。A first structure having a substantially rectangular shape and at least a first drive unit and a second drive unit having substantially the same shape in the longitudinal direction thereof, and substantially the same as the first structure; A second drive unit having a length and a thickness smaller than the width of the first structure, and including at least a third drive unit and a fourth drive unit having substantially the same shape in the longitudinal direction thereof; Wherein the first drive section and the fourth drive section are located diagonally, and the main surface of the first structure has a widthwise direction of the second structure. A vibrator whose sides are aligned,
In the vibrator, the first drive unit and the fourth drive unit are expanded and contracted in the same phase, and the second drive unit and the third drive unit are in the same phase and substantially the same as the first drive unit. A prefix member disposed near an antinode of vibration generated by expanding and contracting at a phase shifted by 90 degrees and a holding member disposed near a node of the vibration;
Holding means for holding the holding member,
Pressing means for pressing the holding means against the moving body so that the prefix member is pressed against the moving body with a predetermined force;
An ultrasonic motor, comprising: 円筒形の圧電セラミック部材と、
前記圧電セラミック部材の内周面に設けられ、接地電極として用いられる共通電極と、
超音波領域の交番電圧が印加されることによって前記圧電セラミック部材の端面の略中心部に楕円進行波が生ずるように、前記圧電セラミック部材の外周面に所定のパターンで設けられた駆動電極と、
前記圧電セラミック部材の端面を閉塞する蓋体と、
前記蓋体の略中心部に配設された接頭部材と、
前記圧電セラミック部材を保持する保持手段と、
前記接頭部材が被移動体に所定の力で押し当てられるように前記保持手段を前記被移動体に押圧する押圧手段と、
を具備することを特徴する超音波モータ。A cylindrical piezoelectric ceramic member;
A common electrode provided on the inner peripheral surface of the piezoelectric ceramic member and used as a ground electrode,
A drive electrode provided in a predetermined pattern on the outer peripheral surface of the piezoelectric ceramic member so that an elliptical traveling wave is generated substantially at the center of the end surface of the piezoelectric ceramic member by applying an alternating voltage in an ultrasonic region,
A lid for closing an end face of the piezoelectric ceramic member,
A prefix member disposed substantially at the center of the lid,
Holding means for holding the piezoelectric ceramic member,
Pressing means for pressing the holding means against the moving body so that the prefix member is pressed against the moving body with a predetermined force;
An ultrasonic motor comprising: 平板リング状の圧電セラミックリングと薄膜状の電極とが交互に積層された円筒状構造体と、
前記円筒状構造体の端面を閉塞する蓋体と、
前記蓋体の略中心部に配設された接頭部材と、
前記円筒状構造体を保持する保持手段と、
前記接頭部材が被移動体に所定の力で押し当てられるように前記保持手段を前記被移動体に押圧する押圧手段と、
を具備し、
前記電極は、
前記圧電セラミックリングの円周回りで所定数に略等分割された駆動電極と、
前記圧電セラミックリングの主面と略同形状のリング状の接地電極と、
を有し、
前記駆動電極は、複数の電極群が構成されるように電気的に接続され、
前記複数の電極群に超音波領域の交番電圧が印加されることによって前記接頭部材に楕円進行波が生ずることを特徴とする超音波モータ。A cylindrical structure in which flat-plate-shaped piezoelectric ceramic rings and thin-film electrodes are alternately stacked,
A lid closing the end face of the cylindrical structure,
A prefix member disposed substantially at the center of the lid,
Holding means for holding the cylindrical structure,
Pressing means for pressing the holding means against the moving body so that the prefix member is pressed against the moving body with a predetermined force;
With
The electrode is
A drive electrode substantially equally divided into a predetermined number around the circumference of the piezoelectric ceramic ring,
A ring-shaped ground electrode having substantially the same shape as the main surface of the piezoelectric ceramic ring,
Has,
The drive electrodes are electrically connected to form a plurality of electrode groups,
An ultrasonic motor wherein an elliptical traveling wave is generated in the prefix member when an alternating voltage in an ultrasonic region is applied to the plurality of electrode groups.
JP2003035177A 2003-02-13 2003-02-13 Vibrator and ultrasonic motor Pending JP2004248399A (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009254198A (en) * 2008-04-10 2009-10-29 Sharp Corp Ultrasonic motor and ultrasonic oscillator
JP2010233338A (en) * 2009-03-26 2010-10-14 Seiko Epson Corp Piezoelectric motor, liquid ejecting apparatus and clock
CN113114065A (en) * 2021-04-23 2021-07-13 吉林大学 Longitudinal-bending mode composite piezoelectric ultrasonic motor for micro equipment and driving method thereof
CN113162463A (en) * 2021-05-11 2021-07-23 哈尔滨工业大学 Ultrasonic motor vibrator with plate-cantilever beam combined structure and excitation method thereof

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009254198A (en) * 2008-04-10 2009-10-29 Sharp Corp Ultrasonic motor and ultrasonic oscillator
US8058773B2 (en) 2008-04-10 2011-11-15 Sharp Kabushiki Kaisha Ultrasonic motor and ultrasonic vibrator
JP2010233338A (en) * 2009-03-26 2010-10-14 Seiko Epson Corp Piezoelectric motor, liquid ejecting apparatus and clock
US8827428B2 (en) 2009-03-26 2014-09-09 Seiko Epson Corporation Piezoelectric motor, liquid ejecting apparatus, and clock
CN113114065A (en) * 2021-04-23 2021-07-13 吉林大学 Longitudinal-bending mode composite piezoelectric ultrasonic motor for micro equipment and driving method thereof
CN113114065B (en) * 2021-04-23 2024-03-19 吉林大学 Longitudinal bending mode compounded piezoelectric ultrasonic motor for micro-device and driving method thereof
CN113162463A (en) * 2021-05-11 2021-07-23 哈尔滨工业大学 Ultrasonic motor vibrator with plate-cantilever beam combined structure and excitation method thereof
CN113162463B (en) * 2021-05-11 2022-12-06 哈尔滨工业大学 Ultrasonic motor vibrator with plate-cantilever beam combined structure and excitation method thereof

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