JP4284917B2

JP4284917B2 - Giant magnetostrictive linear actuator

Info

Publication number: JP4284917B2
Application number: JP2002081799A
Authority: JP
Inventors: 義雄光武; 勝弘平田; 康浩松井; 友彦鈴木
Original assignee: Panasonic Corp; Matsushita Electric Works Ltd
Current assignee: Panasonic Corp; Panasonic Electric Works Co Ltd
Priority date: 2002-03-22
Filing date: 2002-03-22
Publication date: 2009-06-24
Anticipated expiration: 2022-03-22
Also published as: JP2003282991A

Description

【０００１】
【発明の属する技術分野】
本発明は、０．１ｍｍ〜１ｍｍ程度の大変位振動が可能な超磁歪リニアアクチュエータに関するものである。
【０００２】
【従来の技術】
図１９は従来の超磁歪アクチュエータの構成図である。この超磁歪アクチュエータは、駆動力を発生させる超磁歪素子２と、超磁歪素子２と接するようにして配設され出力を外部に伝える出力軸３Ｘと、磁気バイアスを超磁歪素子２に与えるための永久磁石８と、磁気回路を構成するヨーク７Ｘと、超磁歪素子２に予荷重を付与する予荷重ばね４Ｘと、起磁力を付与するための励磁コイル１とからなる。
【０００３】
励磁コイル１に正弦波または矩形波等の交流電流を与えると、図２０に示すように、ヨーク７Ｘおよび超磁歪素子２で構成される磁路中を通る磁束も交流的に変化する。これにより、磁歪が生じ、駆動周波数と同じ周波数の微小振動が生じる。その振動出力が出力軸３Ｘを通して外部へ伝達される。
【０００４】
図２１は超磁歪リニアアクチュエータの構成図である（特願２００１−２６２８７５）。この超磁歪リニアアクチュエータは、Ｌ字状の可動部３Ｙを用い、てこの原理と機械的共振を利用した振幅拡大機構を有している。また、図２２に示すように、Ｌ字状の可動部３Ｙを一対用いてカウンタ動作を実現した超磁歪リニアアクチュエータも提案されている。なお、図２１，図２２中の４は予荷重皿バネである。
【０００５】
【発明が解決しようとする課題】
図１９のアクチュエータでは、励磁コイル１を励磁することにより、出力軸３Ｘに出力として微小振動が生じるが、出力変位は、超磁歪素子２の伸縮による変位の振幅そのものであり、超磁歪素子２の軸方向の長さに対して最大１０００〜２０００ｐｐｍの微小振動しか取り出せない。例えば、超磁歪素子の軸方向の長さを１０ｍｍとすると、最大１０〜２０μｍ程度の振動となる。
【０００６】
図２１のアクチュエータでは、てこの原理と機械的共振を利用した振幅拡大機構により大振幅のリニア駆動が可能になるが、可動部３Ｙが超磁歪素子２の伸縮方向に対してほぼ直交方向に運動するので、振動が発生する。
【０００７】
図２２のアクチュエータでは、一対の可動部３Ｙが互いに逆向きに運動するので可動部３Ｙの運動方向の振動は大幅に低減できるが、超磁歪素子２の伸縮方向の振動を抑えることができない。
【０００８】
なお、図２１，図２２のアクチュエータは開磁路構造であり、磁気効率が悪いという問題もある。
【０００９】
本発明は、上記事情に鑑みてなされたものであり、振動の小さな超磁歪リニアアクチュエータを提供することを目的とする。
【００１０】
【課題を解決するための手段】
上記課題を解決するための請求項１記載の発明の超磁歪リニアアクチュエータは、極性が交番する磁界を発生させるための励磁コイルと、この励磁コイルによる極性が交番する磁界の強さによって長さが弾性変化する超磁歪素子と、この超磁歪素子の長さが弾性変化する方向におけるその超磁歪素子の両側にそれぞれ設けられる一対の可動部と、これら一対の可動部に対し超磁歪素子側へ予荷重を与える付加手段とを備え、各可動部の作用点となる一端と他端との間の支点寄りの両可動部に上記超磁歪素子の両端がそれぞれ接することを特徴とする。
【００１１】
請求項２記載の発明は、請求項１記載の超磁歪リニアアクチュエータにおいて、励磁コイルおよび超磁歪素子は、固定部材の両側に設けられる２組の励磁コイルおよび超磁歪素子により構成され、一方の組みの超磁歪素子の一端と他方の組みの超磁歪素子の一端とが一対の可動部とそれぞれ接することを特徴とする。
【００１２】
請求項３記載の発明は、請求項２記載の超磁歪リニアアクチュエータにおいて、付加手段が、超磁歪素子への予荷重を各可動部における上記超磁歪素子の両端が接する部位よりも支点寄りの位置に付加することを特徴とする。
【００１３】
請求項４記載の発明は、請求項１または２記載の超磁歪リニアアクチュエータにおいて、一対の可動部をこれらの各他端側で支持するとともに一対の可動部間の励磁コイルおよび超磁歪素子を支持する支持体と、一対の可動部間に設けられこれらの間の励磁コイルおよび超磁歪素子を介して支持体と対向する磁性部材とを備え、一対の可動部および支持体は磁性体であり、超磁歪素子、一対の可動部、支持体および磁性部材により閉磁路を形成することを特徴とする。
【００１４】
請求項５記載の発明は、請求項４記載の超磁歪リニアアクチュエータにおいて、磁性部材が、一対の可動部の運動方向を含む平面と直交する方向において、一定の空隙を介して一対の可動部に対向するように配置されることを特徴とする。
【００１５】
請求項６記載の発明の超磁歪リニアアクチュエータは、磁性材料により一の開口点を持つ断面Ｃ字状に形成されるヨークを備えるとともに、極性が交番する磁界を発生させるための励磁コイルと、この励磁コイルによる極性が交番する磁界の強さによって長さが弾性変化する超磁歪素子と、ヨークの開口点から一部が外部に突出する可動部と、超磁歪素子の長さが弾性変化する方向におけるその超磁歪素子の両側に予荷重を付加する付加手段とを上記ヨークの内部に備え、励磁コイルおよび超磁歪素子は可動部の残部の両側に設けられる２組の励磁コイルおよび超磁歪素子により構成され、付加手段はヨークの内壁に固定されて一方の組みの超磁歪素子の一端と他方の組みの超磁歪素子の一端とに予荷重を与え、可動部が自己の残部先端寄りで２組の超磁歪素子により狭持されることを特徴とする。
【００１６】
ここで、本発明では、可動部の運動方向と超磁歪素子の伸縮方向とを一致させた振幅拡大機構により低振動化を図る。また、閉磁路構造により高効率化を実現する。
【００１７】
一般的な磁歪素子は、純Ｎｉ、Ｆｅ−Ｎｉ系合金、ＮｉやＺｎを添加したフェライト（酸化鉄）などの材料を用いて形成され、磁歪により全長の数十ｐｐｍ程度の長さ弾性変化する。これに対して、超磁歪材料は、テルビウム（Ｔｂ）やディスプロジウム（Ｄｙ）などの希土類元素と鉄の合金により成り、磁歪により全長の１０００〜２０００ｐｐｍ程度の長さ弾性変化する。このような超磁歪素子は、米国海軍によって開発され、ＥＴＲＥＭＡ社によって実用化され、Ｔｅｒｆｅｎｏｌ−Ｄ（Ｔｂ_0.3Ｄｙ_0.7Ｆｅ_1.91）などが知られている。本発明ではこのような超磁歪素子などが用いられる。
【００１８】
上記構成の本発明によれば、てこ機構による増幅率、および共振系による増幅率を乗じたものが出力振幅となるため、大振幅のリニアアクチュエータを実現でき、可動部の出力の運動方向と超磁歪素子の伸縮方向とを一致させた振幅拡大機構により振動を抑え、閉磁路構造により高効率化が可能となる。
【００１９】
【発明の実施の形態】
（第１実施形態）
図１は本発明に係る第１実施形態の超磁歪リニアアクチュエータの構成図である。
【００２０】
第１実施形態の超磁歪リニアアクチュエータは、図１に示すように、極性が交番する磁界を発生させるための励磁コイル１と、この励磁コイル１の軸内に設けられ励磁コイル１による極性が交番する磁界の強さによって長さが弾性変化する棒状の超磁歪素子２と、この超磁歪素子２の長さが弾性変化する方向におけるその超磁歪素子２の両側にそれぞれ設けられる一対の可動部３と、これら一対の可動部３に対し超磁歪素子２側へ予荷重を与える一対の予荷重皿バネ４と、一対の可動部３間の励磁コイル１および超磁歪素子２を支持する支持体５とを備えている。
【００２１】
この支持体５は断面コ字状に形成されており、支持体５の各端部５１の内面に予荷重皿バネ４が固着されている。そして、各可動部３の作用点３２となる一端と他端３１との間の支点寄りの両可動部３に超磁歪素子２の両端がそれぞれ接する配置構造になっている。ただし、図１の例では、超磁歪素子２の両端に半球状の駆動力伝達部材２１が設けられており、これらの駆動力伝達部材２１の極点が動作点となって両可動部３と接する。また、超磁歪リニアアクチュエータは、各可動部の作用点３２側が超磁歪素子２の伸縮による振動に共振するように構成される。さらに、支点は、動作点の上側（作用点３２側）のその動作点寄りに設けられる。
【００２２】
ここで、励磁コイル１の励磁周波数の２倍の周波数で各可動部３が運動する。振幅は、支点から動作点までの長さをｌ₁、支点から作用点３２までの長さをｌ₂とすると、超磁歪素子２の伸縮×０．５×ｌ₂／ｌ₁×共振増幅率で拡大される。
【００２３】
このような構造の超磁歪リニアアクチュエータによれば、可動部３の作用点３２の振動方向と超磁歪素子２の伸縮方向とが一致し、そして一対の可動部３が互いに逆方向に運動するので、各運動による振動がキャンセルされることになり、振動の小さな超磁歪リニアアクチュエータを実現することができる。
【００２４】
なお、第１実施形態では、予荷重を付加する付加手段として皿バネが使用される構成になっているが、本発明の付加手段は、これに限らず、例えばコイルバネ等の他の弾性体でもよい。
【００２５】
また、磁気バイアスをかけない構成になっているが、磁石または直流電流により磁気バイアスをかける構成でもよい。磁気バイアスをかけると、励磁電流の周波数と同じ周波数で可動部が運動する。
【００２６】
（第２実施形態）
図２は本発明に係る第２実施形態の超磁歪リニアアクチュエータの構成図である。
【００２７】
第２実施形態の超磁歪リニアアクチュエータは、図２に示すように、第１実施形態との相違点として、励磁コイルおよび超磁歪素子が、支持体５に連設される板状の固定部材５２の両側に設けられる２組の励磁コイル１Ａ，１Ｂおよび超磁歪素子２Ａ，２Ｂにより構成され、一方の組みの超磁歪素子２Ａの一端と他方の組みの超磁歪素子２Ｂの一端とが一対の可動部３とそれぞれ接する構造になっている。
【００２８】
このような構造の超磁歪リニアアクチュエータによれば、２つの超磁歪素子２Ａ，２Ｂの各他端が固定部材５２に固定されるので、予荷重皿バネ４による予荷重の調節を左右独立で行うことができる。これにより、初期調節が容易となり生産性が向上する。
【００２９】
（第３実施形態）
図３は本発明に係る第３実施形態の超磁歪リニアアクチュエータの構成図である。
【００３０】
第３実施形態の超磁歪リニアアクチュエータは、第２実施形態との相違点として、超磁歪素子への予荷重をてこの原理を用いて付加する構造になっている。図３の例では、励磁コイル１Ａ，１Ｂおよび超磁歪素子２Ａ，２Ｂの作用点３２側の各可動部３に孔３ａが穿設され、両孔３ａに棒状の予荷重付加用部材４Ａが挿通されている。そして、予荷重付加用部材４Ａの両端に、外形寸法が大きい端部４１Ａが固着され、各端部４１Ａと可動部３との間に、予荷重付加用部材４Ａに挿通された予荷重付加バネ４２Ａが設けられている。
【００３１】
このような構造の超磁歪リニアアクチュエータによれば、てこの原理により、予荷重を増幅することができ、調整の幅が広がる。また、予荷重を超磁歪素子の伸縮方向に設置する必要がなく、横幅を小さくすることができる。
【００３２】
（第４実施形態）
図４は本発明に係る第４実施形態の超磁歪リニアアクチュエータの構成図、図５は同超磁歪リニアアクチュエータの特徴となる閉磁路の説明図、図６は同超磁歪リニアアクチュエータの比較対照となる閉磁路の説明図である。
【００３３】
第４実施形態の超磁歪リニアアクチュエータは、第１実施形態との相違点として、図４に示すように、一対の可動部３間に設けられこれらの間の励磁コイル１および超磁歪素子２を介して支持体５と対向する、例えば鉄製の磁路バイパス６を備え、一対の可動部３および支持体５は磁性体であり、超磁歪素子２、一対の可動部３、支持体５および磁路バイパス６により閉磁路を形成する構造になっている。
【００３４】
このような構造の超磁歪リニアアクチュエータによれば、図５に示すように閉磁路が形成されるから、図６に示す開磁路のものよりも磁気回路の磁気抵抗が減少し、超磁歪素子２を伸縮させるために必要な交番磁界を発生させる電流を抑えることができるため、高効率化を図ることができる。
【００３５】
なお、第４実施形態では、磁路バイパス６を第１実施形態の超磁歪リニアアクチュエータに設けた構造になっているが、図７に示すように、磁路バイパス６を第２実施形態の超磁歪リニアアクチュエータに設ける構造にしてもよい。この構造でも、図８に示すように閉磁路が形成されるから、図９に示す開磁路のものよりも磁気回路の磁気抵抗が減少し、超磁歪素子２Ａ，２Ｂを伸縮させるために必要な交番磁界を発生させる電流を抑えることができるため、高効率化を図ることができる。ただし、図７における固定部材５２も磁性体になる。
【００３６】
（第５実施形態）
図１０は本発明に係る第５実施形態の超磁歪リニアアクチュエータの外観図、図１１は同超磁歪リニアアクチュエータの構成図、図１２は同超磁歪リニアアクチュエータを出力部側から見た図である。
【００３７】
第５実施形態の超磁歪リニアアクチュエータは、第４実施形態との相違点として、磁路バイパスと一対の可動部との間の空隙が、可動部の運動に依らず一定となることを特徴とする。図１０〜図１２の例では、磁路バイパス６Ａは２枚の平行磁性体により成っている。
【００３８】
ここで、磁路バイパス６Ａから可動部３、可動部３から磁路バイパス６Ａへの磁束の流れに対して可動部３の運動方向を垂直にすることにより、磁路中の空隙を一定とする。
【００３９】
図４，図７の構造では、可動部３の運動により磁路中の空隙が大きくなり、磁路の磁気抵抗が増加するが、第５実施形態によれば、可動部３の運動に対して磁路中の空隙が一定となり、安定的に高効率化を図ることができる。
【００４０】
なお、第５実施形態では、磁路バイパス６Ａを図４の超磁歪リニアアクチュエータに設けた構造になっているが、図１３〜図１５に示すように、磁路バイパス６Ａを図７の超磁歪リニアアクチュエータに設けてもよい。この構造でも安定的に高効率化を図ることができる。
【００４１】
また、図１０〜図１５の例では、磁路バイパス６Ａは２枚の平行磁性体により成るが、図１６に示すようなＨ字状の磁性体により磁路バイパス６Ｂを形成するようにしてもよい。この構造でも安定的に高効率化を図ることができる。
【００４２】
（第６実施形態）
図１７は本発明に係る第６実施形態の超磁歪リニアアクチュエータの外観図、図１８は同超磁歪リニアアクチュエータの構成図である。
【００４３】
第６実施形態の超磁歪リニアアクチュエータは、図１７，図１８に示すように、磁性材料により一の開口点（支点）７ａを持つ断面Ｃ字状に形成されるヨーク７を備えているとともに、極性が交番する磁界を発生させるための励磁コイル１と、この励磁コイル１による極性が交番する磁界の強さによって長さが弾性変化する超磁歪素子２と、ヨーク７の開口点７ａから一部３２Ａが外部に突出する可動部３Ａと、超磁歪素子２の長さが弾性変化する方向におけるその超磁歪素子２の両側に予荷重を与える一対の予荷重皿バネ４とをヨーク７の内部に備えている。
【００４４】
励磁コイル１および超磁歪素子２は、可動部７の残部３１Ａの両側に設けられる２組の励磁コイル１Ａ，１Ｂおよび超磁歪素子２Ａ，２Ｂにより構成され、各予荷重皿バネ４は、ヨーク７の内壁に固定されて、一方の組みの超磁歪素子２Ａの一端と他方の組みの超磁歪素子２Ｂの一端とに予荷重を与え、可動部３Ａが自己の残部３１Ａ先端寄りで２組の超磁歪素子２Ａ，２Ｂにより狭持される構造になっている。
【００４５】
ここで、超磁歪素子２Ａ，２Ｂは、一方の超磁歪素子が伸びている時にもう一方の超磁歪素子が縮んだ状態となるように励磁される。これにより、２つの超磁歪素子の伸縮に応じてその伸縮方向に可動部３Ａが運動する。なお、各超磁歪素子と接する、可動部３Ａの残部３１Ａの点が動作点であり、可動部３Ａの一部３２Ａの先端が作用点となる。また、開口点（支点）７ａと作用点との間の距離は、開口点（支点）７ａと動作点との間の距離よりも長く設定される。
【００４６】
このような構造の超磁歪リニアアクチュエータでは、２組の励磁コイル１Ａ，１Ｂに交互に通電することにより可動部３Ａが往復動するが、可動部３Ａがどちらの方向に運動しているときでも超磁歪素子による駆動力が生じる。また、ほぼ閉磁路構造であるから、高効率化を図ることができる。
【００４７】
なお、第６実施形態では、磁気バイアスをかけない構成になっているが、磁石または直流電流により磁気バイアスをかける構成でもよい。磁気バイアスをかけると、励磁電流の周波数と同じ周波数で可動部が運動する。
【００４８】
また、ヨーク全体の構造は、図１７に示すように箱形に限らず、Ｃ字状の筒形でもよい。
【００４９】
【発明の効果】
以上のことから明らかなように、請求項１記載の発明によれば、極性が交番する磁界を発生させるための励磁コイルと、この励磁コイルによる極性が交番する磁界の強さによって長さが弾性変化する超磁歪素子と、この超磁歪素子の長さが弾性変化する方向におけるその超磁歪素子の両側にそれぞれ設けられる一対の可動部と、これら一対の可動部に対し超磁歪素子側へ予荷重を与える付加手段とを備え、各可動部の作用点となる一端と他端との間の支点寄りの両可動部に上記超磁歪素子の両端がそれぞれ接するので、可動部の作用点の振動方向と超磁歪素子の伸縮方向とが一致し、そして一対の可動部が互いに逆方向に運動するので、各運動による振動がキャンセルされることになり、振動の小さな超磁歪リニアアクチュエータを実現することができる。
【００５０】
請求項２記載の発明によれば、請求項１記載の超磁歪リニアアクチュエータにおいて、励磁コイルおよび超磁歪素子は、固定部材の両側に設けられる２組の励磁コイルおよび超磁歪素子により構成され、一方の組みの超磁歪素子の一端と他方の組みの超磁歪素子の一端とが一対の可動部とそれぞれ接するのであり、この構造でも、振動が小さくなる。
【００５１】
請求項３記載の発明によれば、請求項２記載の超磁歪リニアアクチュエータにおいて、付加手段が、超磁歪素子への予荷重を各可動部における上記超磁歪素子の両端が接する部位よりも支点寄りの位置に付加するので、てこの原理により、予荷重を増幅することができ、調整の幅が広がる。
【００５２】
請求項４記載の発明によれば、請求項１または２記載の超磁歪リニアアクチュエータにおいて、一対の可動部をこれらの各他端側で支持するとともに一対の可動部間の励磁コイルおよび超磁歪素子を支持する支持体と、一対の可動部間に設けられこれらの間の励磁コイルおよび超磁歪素子を介して支持体と対向する磁性部材とを備え、一対の可動部および支持体は磁性体であり、超磁歪素子、一対の可動部、支持体および磁性部材により閉磁路を形成するので、開磁路よりも磁気回路の磁気抵抗が減少し、超磁歪素子を伸縮させるために必要な交番磁界を発生させる電流を抑えることができるため、高効率化を図ることができる。
【００５３】
請求項５記載の発明によれば、請求項４記載の超磁歪リニアアクチュエータにおいて、磁性部材が、一対の可動部の運動方向を含む平面と直交する方向において、一定の空隙を介して一対の可動部に対向するように配置されるので、安定的に高効率化を図ることができる。
【００５４】
請求項６記載の発明によれば、磁性材料により一の開口点を持つ断面Ｃ字状に形成されるヨークを備えるとともに、極性が交番する磁界を発生させるための励磁コイルと、この励磁コイルによる極性が交番する磁界の強さによって長さが弾性変化する超磁歪素子と、ヨークの開口点から一部が外部に突出する可動部と、超磁歪素子の長さが弾性変化する方向におけるその超磁歪素子の両側に予荷重を付加する付加手段とを上記ヨークの内部に備え、励磁コイルおよび超磁歪素子は可動部の残部の両側に設けられる２組の励磁コイルおよび超磁歪素子により構成され、付加手段はヨークの内壁に固定されて一方の組みの超磁歪素子の一端と他方の組みの超磁歪素子の一端とに予荷重を与え、可動部が自己の残部先端寄りで２組の超磁歪素子により狭持されるので、２つの励磁コイルに交互に通電することにより可動部が往復動するが、可動部がどちらの方向に運動しているときでも超磁歪素子による逆向きの駆動力が生じるから、振動の小さな超磁歪リニアアクチュエータを実現することができる。また、閉磁路構造であるから、高効率化を図ることができる。
【図面の簡単な説明】
【図１】本発明に係る第１実施形態の超磁歪リニアアクチュエータの構成図である。
【図２】本発明に係る第２実施形態の超磁歪リニアアクチュエータの構成図である。
【図３】本発明に係る第３実施形態の超磁歪リニアアクチュエータの構成図である。
【図４】本発明に係る第４実施形態の超磁歪リニアアクチュエータの構成図である。
【図５】同超磁歪リニアアクチュエータの特徴となる閉磁路の説明図である。
【図６】同超磁歪リニアアクチュエータの比較対照となる閉磁路の説明図である。
【図７】図４中の磁路バイパスを図２の超磁歪リニアアクチュエータに設けた場合の構造を示す図である。
【図８】同超磁歪リニアアクチュエータの特徴となる閉磁路の説明図である。
【図９】同超磁歪リニアアクチュエータの比較対照となる閉磁路の説明図である。
【図１０】本発明に係る第５実施形態の超磁歪リニアアクチュエータの外観図である。
【図１１】同超磁歪リニアアクチュエータの構成図である。
【図１２】同超磁歪リニアアクチュエータを出力部側から見た図である。
【図１３】図１０〜図１２中の磁路バイパスを図２の超磁歪リニアアクチュエータに設けた場合の外観図である。
【図１４】同超磁歪リニアアクチュエータの構成図である。
【図１５】同超磁歪リニアアクチュエータを出力部側から見た図である。
【図１６】別の磁路バイパスの構造例を示す図である。
【図１７】本発明に係る第６実施形態の超磁歪リニアアクチュエータの外観図である。
【図１８】同超磁歪リニアアクチュエータの構成図である。
【図１９】従来の超磁歪アクチュエータの構成図である。
【図２０】同超磁歪アクチュエータの磁束の流れを示す図である。
【図２１】特願２００１−２６２８７５で提案されている超磁歪リニアアクチュエータの構成図である。
【図２２】特願２００１−２６２８７５で提案されているカウンタ動作を実現した超磁歪リニアアクチュエータの構成図である。
【符号の説明】
１，１Ａ，１Ｂ励磁コイル
２，２Ａ，２Ｂ超磁歪素子
３，３Ａ可動部
４予荷重皿バネ
４Ａ予荷重付加用部材
４２Ａ予荷重付加バネ
５支持体
５２固定部材
６，６Ａ，６Ｂ磁路バイパス
７ヨーク[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a giant magnetostrictive linear actuator capable of large displacement vibration of about 0.1 mm to 1 mm.
[0002]
[Prior art]
FIG. 19 is a configuration diagram of a conventional giant magnetostrictive actuator. This giant magnetostrictive actuator is provided with a giant magnetostrictive element 2 that generates a driving force, an output shaft 3X that is disposed in contact with the giant magnetostrictive element 2 and transmits an output to the outside, and a magnetic bias that is applied to the giant magnetostrictive element 2. It comprises a permanent magnet 8, a yoke 7X constituting a magnetic circuit, a preload spring 4X for applying a preload to the giant magnetostrictive element 2, and an exciting coil 1 for applying a magnetomotive force.
[0003]
When an alternating current such as a sine wave or a rectangular wave is applied to the exciting coil 1, the magnetic flux passing through the magnetic path formed by the yoke 7X and the giant magnetostrictive element 2 also changes in an alternating manner as shown in FIG. As a result, magnetostriction occurs, and minute vibrations having the same frequency as the drive frequency occur. The vibration output is transmitted to the outside through the output shaft 3X.
[0004]
FIG. 21 is a configuration diagram of a giant magnetostrictive linear actuator (Japanese Patent Application No. 2001-262875). This giant magnetostrictive linear actuator uses an L-shaped movable part 3Y and has an amplitude expansion mechanism utilizing the principle of this lever and mechanical resonance. Further, as shown in FIG. 22, a giant magnetostrictive linear actuator that realizes a counter operation using a pair of L-shaped movable parts 3Y has also been proposed. In FIG. 21 and FIG. 22, 4 is a preload disc spring.
[0005]
[Problems to be solved by the invention]
In the actuator of FIG. 19, when the exciting coil 1 is excited, minute vibrations are generated as an output on the output shaft 3X. The output displacement is the displacement amplitude itself due to the expansion and contraction of the giant magnetostrictive element 2, and Only minute vibrations of 1000 to 2000 ppm at maximum can be extracted with respect to the length in the axial direction. For example, assuming that the length of the giant magnetostrictive element in the axial direction is 10 mm, the maximum vibration is about 10 to 20 μm.
[0006]
In the actuator shown in FIG. 21, a large-amplitude linear drive is possible by an amplitude expanding mechanism using the lever principle and mechanical resonance, but the movable portion 3Y moves in a direction substantially orthogonal to the expansion / contraction direction of the giant magnetostrictive element 2. As a result, vibration occurs.
[0007]
In the actuator shown in FIG. 22, the pair of movable parts 3Y move in directions opposite to each other, so that vibration in the movement direction of the movable part 3Y can be greatly reduced, but vibration in the expansion / contraction direction of the giant magnetostrictive element 2 cannot be suppressed.
[0008]
The actuators in FIGS. 21 and 22 have an open magnetic circuit structure, and there is a problem that the magnetic efficiency is poor.
[0009]
The present invention has been made in view of the above circumstances, and an object thereof is to provide a giant magnetostrictive linear actuator with small vibration.
[0010]
[Means for Solving the Problems]
The giant magnetostrictive linear actuator according to the first aspect of the present invention for solving the above-mentioned problem has an excitation coil for generating a magnetic field with alternating polarity and a length depending on the strength of the magnetic field with alternating polarity by the excitation coil. An elastically changing giant magnetostrictive element, a pair of movable parts respectively provided on both sides of the giant magnetostrictive element in the direction in which the length of the giant magnetostrictive element is elastically changed, and the pair of movable parts are preliminarily moved toward the giant magnetostrictive element side. And an adding means for applying a load, wherein both ends of the giant magnetostrictive element are in contact with both movable parts near the fulcrum between one end and the other end, which are the action points of each movable part.
[0011]
According to a second aspect of the present invention, in the giant magnetostrictive linear actuator of the first aspect, the exciting coil and the giant magnetostrictive element are composed of two pairs of exciting coils and giant magnetostrictive elements provided on both sides of the fixed member. One end of the giant magnetostrictive element and the other end of the other pair of giant magnetostrictive elements are in contact with the pair of movable parts, respectively.
[0012]
According to a third aspect of the present invention, in the giant magnetostrictive linear actuator according to the second aspect, the additional means places the preload on the giant magnetostrictive element at a position closer to the fulcrum than the part of each movable portion where both ends of the giant magnetostrictive element are in contact characterized by adding to.
[0013]
According to a fourth aspect of the present invention, in the giant magnetostrictive linear actuator according to the first or second aspect, the pair of movable parts are supported on the other end sides thereof, and the excitation coil and the giant magnetostrictive element between the pair of movable parts are supported. And a magnetic member that is provided between the pair of movable parts and faces the support via the exciting coil and the giant magnetostrictive element between them, the pair of movable parts and the support body are magnetic bodies, A closed magnetic path is formed by a giant magnetostrictive element, a pair of movable parts, a support and a magnetic member.
[0014]
According to a fifth aspect of the present invention, in the giant magnetostrictive linear actuator according to the fourth aspect of the present invention, the magnetic member is moved to the pair of movable parts via a certain gap in a direction perpendicular to the plane including the direction of motion of the pair of movable parts. It arrange | positions so that it may oppose .
[0015]
According to a sixth aspect of the present invention, there is provided a giant magnetostrictive linear actuator including a yoke formed in a C-shaped cross section having one opening point by a magnetic material, and an exciting coil for generating a magnetic field with alternating polarity, A giant magnetostrictive element whose length elastically changes depending on the strength of the magnetic field with alternating polarity by the exciting coil, a movable part partially protruding outward from the opening point of the yoke, and a direction in which the length of the giant magnetostrictive element changes elastically And an additional means for applying a preload on both sides of the giant magnetostrictive element in the yoke, and the exciting coil and the giant magnetostrictive element are provided by two sets of exciting coil and giant magnetostrictive element provided on both sides of the remaining part of the movable part. The additional means is fixed to the inner wall of the yoke and applies a preload to one end of one set of super magnetostrictive elements and one end of the other set of super magnetostrictive elements. The two sets of super-magnetostrictive element, characterized in that it is sandwiched.
[0016]
Here, in the present invention, the vibration is reduced by an amplitude enlarging mechanism in which the moving direction of the movable part and the expansion / contraction direction of the giant magnetostrictive element are matched. In addition, high efficiency is realized by the closed magnetic circuit structure.
[0017]
A general magnetostrictive element is formed using a material such as pure Ni, an Fe-Ni alloy, ferrite (iron oxide) added with Ni or Zn, and changes in elasticity by a length of several tens of ppm due to magnetostriction. . On the other hand, the giant magnetostrictive material is made of an alloy of a rare earth element such as terbium (Tb) or dysprodium (Dy) and iron and elastically changes in length by about 1000 to 2000 ppm due to magnetostriction. Such a giant magnetostrictive element has been developed by the US Navy, put into practical use by ETREMA, and Terfenol-D (Tb _0.3 Dy _0.7 Fe _1.91 ) is known. In the present invention, such a giant magnetostrictive element is used.
[0018]
According to the present invention having the above configuration, since the output amplitude is obtained by multiplying the amplification factor by the lever mechanism and the amplification factor by the resonance system, a large-amplitude linear actuator can be realized, and the movement direction and super Vibration can be suppressed by an amplitude expansion mechanism that matches the expansion and contraction direction of the magnetostrictive element, and high efficiency can be achieved by a closed magnetic circuit structure.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
FIG. 1 is a configuration diagram of a giant magnetostrictive linear actuator according to a first embodiment of the present invention.
[0020]
As shown in FIG. 1, the giant magnetostrictive linear actuator of the first embodiment has an excitation coil 1 for generating a magnetic field with alternating polarity, and the polarity of the excitation coil 1 provided in the axis of the excitation coil 1 is alternating. And a pair of movable parts 3 provided on both sides of the super magnetostrictive element 2 in the direction in which the length of the super magnetostrictive element 2 changes elastically. A pair of preload disc springs 4 for applying a preload to the pair of movable parts 3 toward the giant magnetostrictive element 2, and a support 5 for supporting the exciting coil 1 and the giant magnetostrictive element 2 between the pair of movable parts 3. And.
[0021]
The support 5 is formed in a U-shaped cross section, and the preload disc spring 4 is fixed to the inner surface of each end 51 of the support 5. In addition, both ends of the giant magnetostrictive element 2 are in contact with both movable portions 3 near the fulcrum between one end and the other end 31 serving as the action point 32 of each movable portion 3. However, in the example of FIG. 1, hemispherical driving force transmission members 21 are provided at both ends of the giant magnetostrictive element 2, and the poles of these driving force transmission members 21 serve as operating points and come into contact with both movable parts 3. . The giant magnetostrictive linear actuator is configured such that the action point 32 side of each movable part resonates with vibration caused by expansion and contraction of the giant magnetostrictive element 2. Further, the fulcrum is provided near the operating point above the operating point (on the side of the action point 32).
[0022]
Here, each movable part 3 moves at a frequency twice the excitation frequency of the excitation coil 1. As for the amplitude, if the length from the fulcrum to the operating point is l ₁ , and the length from the fulcrum to the action point 32 is l ₂ , the expansion and contraction of the giant magnetostrictive element 2 × 0.5 × l ₂ / l ₁ × resonance amplification factor It is expanded by.
[0023]
According to the giant magnetostrictive linear actuator having such a structure, the vibration direction of the action point 32 of the movable part 3 coincides with the expansion / contraction direction of the giant magnetostrictive element 2, and the pair of movable parts 3 move in directions opposite to each other. The vibration due to each motion is canceled, and a giant magnetostrictive linear actuator with small vibration can be realized.
[0024]
In the first embodiment, a disc spring is used as an adding means for applying a preload. However, the adding means of the present invention is not limited to this, and may be another elastic body such as a coil spring. Good.
[0025]
In addition, the magnetic bias is not applied, but the magnetic bias may be applied by a magnet or a direct current. When a magnetic bias is applied, the movable part moves at the same frequency as the excitation current.
[0026]
(Second Embodiment)
FIG. 2 is a block diagram of a giant magnetostrictive linear actuator according to a second embodiment of the present invention.
[0027]
As shown in FIG. 2, the giant magnetostrictive linear actuator of the second embodiment is different from the first embodiment in that a plate-like fixing member 52 in which an exciting coil and a giant magnetostrictive element are connected to the support 5. Are composed of two sets of exciting coils 1A and 1B and super magnetostrictive elements 2A and 2B, and one end of one set of super magnetostrictive elements 2A and one end of the other set of super magnetostrictive elements 2B are a pair of movable members. Each part 3 is in contact with the part 3.
[0028]
According to the giant magnetostrictive linear actuator having such a structure, since the other ends of the two giant magnetostrictive elements 2A and 2B are fixed to the fixing member 52, the preload adjustment by the preload disc spring 4 is performed independently on the left and right. be able to. This facilitates initial adjustment and improves productivity.
[0029]
(Third embodiment)
FIG. 3 is a block diagram of a giant magnetostrictive linear actuator according to a third embodiment of the present invention.
[0030]
As a difference from the second embodiment, the giant magnetostrictive linear actuator of the third embodiment has a structure in which a preload is applied to the giant magnetostrictive element using this principle. In the example of FIG. 3, a hole 3a is formed in each movable portion 3 on the side of the action point 32 of the exciting coils 1A and 1B and the giant magnetostrictive elements 2A and 2B, and a rod-shaped preload addition member 4A is inserted into both the holes 3a. Has been. Then, end portions 41A having large outer dimensions are fixed to both ends of the preload addition member 4A, and the preload addition springs inserted between the end portions 41A and the movable portion 3 through the preload addition member 4A. 42A is provided.
[0031]
According to the giant magnetostrictive linear actuator having such a structure, the preload can be amplified by the lever principle, and the range of adjustment is widened. Further, it is not necessary to install a preload in the expansion / contraction direction of the giant magnetostrictive element, and the lateral width can be reduced.
[0032]
(Fourth embodiment)
FIG. 4 is a configuration diagram of a giant magnetostrictive linear actuator according to a fourth embodiment of the present invention, FIG. 5 is an explanatory diagram of a closed magnetic path that is characteristic of the giant magnetostrictive linear actuator, and FIG. 6 is a comparison and contrast of the giant magnetostrictive linear actuator. It is explanatory drawing of the closed magnetic circuit which becomes.
[0033]
As shown in FIG. 4, the giant magnetostrictive linear actuator of the fourth embodiment is provided between a pair of movable parts 3 and includes an exciting coil 1 and a giant magnetostrictive element 2 between them. The pair of movable parts 3 and the support body 5 are magnetic bodies, and are opposed to the support body 5 via, for example, an iron magnetic path bypass 6. The giant magnetostrictive element 2, the pair of movable sections 3, the support body 5, and the magnetic body A closed magnetic path is formed by the path bypass 6.
[0034]
According to the giant magnetostrictive linear actuator having such a structure, since the closed magnetic circuit is formed as shown in FIG. 5, the magnetoresistance of the magnetic circuit is reduced as compared with that of the open magnetic circuit shown in FIG. Since the electric current which generates the alternating magnetic field required for expanding and contracting 2 can be suppressed, high efficiency can be achieved.
[0035]
In the fourth embodiment, the magnetic path bypass 6 is provided in the giant magnetostrictive linear actuator of the first embodiment. However, as shown in FIG. You may make it the structure provided in a magnetostriction linear actuator. Even in this structure, a closed magnetic circuit is formed as shown in FIG. 8, so that the magnetic resistance of the magnetic circuit is smaller than that of the open magnetic circuit shown in FIG. 9, and is necessary for expanding and contracting the giant magnetostrictive elements 2A and 2B. Since it is possible to suppress a current that generates an alternating magnetic field, high efficiency can be achieved. However, the fixing member 52 in FIG. 7 is also a magnetic body.
[0036]
(Fifth embodiment)
FIG. 10 is an external view of a giant magnetostrictive linear actuator according to a fifth embodiment of the present invention, FIG. 11 is a configuration diagram of the giant magnetostrictive linear actuator, and FIG. 12 is a view of the giant magnetostrictive linear actuator as viewed from the output side. .
[0037]
The difference between the giant magnetostrictive linear actuator of the fifth embodiment and the fourth embodiment is that the gap between the magnetic path bypass and the pair of movable parts is constant regardless of the movement of the movable part. To do. 10 to 12, the magnetic path bypass 6A is composed of two parallel magnetic bodies.
[0038]
Here, by making the moving direction of the movable part 3 perpendicular to the flow of magnetic flux from the magnetic path bypass 6A to the movable part 3 and from the movable part 3 to the magnetic path bypass 6A, the gap in the magnetic path is made constant. .
[0039]
4 and 7, the movement of the movable part 3 increases the gap in the magnetic path and increases the magnetic resistance of the magnetic path. According to the fifth embodiment, the movement of the movable part 3 The air gap in the magnetic path is constant, and high efficiency can be achieved stably.
[0040]
In the fifth embodiment, the magnetic path bypass 6A is provided in the giant magnetostrictive linear actuator of FIG. 4. However, as shown in FIGS. 13 to 15, the magnetic path bypass 6A is replaced with the giant magnetostriction of FIG. You may provide in a linear actuator. Even with this structure, high efficiency can be achieved stably.
[0041]
10 to 15, the magnetic path bypass 6A is composed of two parallel magnetic bodies. However, the magnetic path bypass 6B may be formed of an H-shaped magnetic body as shown in FIG. Good. Even with this structure, high efficiency can be achieved stably.
[0042]
(Sixth embodiment)
FIG. 17 is an external view of a giant magnetostrictive linear actuator according to a sixth embodiment of the present invention, and FIG. 18 is a configuration diagram of the giant magnetostrictive linear actuator.
[0043]
As shown in FIGS. 17 and 18, the giant magnetostrictive linear actuator of the sixth embodiment includes a yoke 7 formed in a C-shaped section having one opening point (fulcrum) 7a from a magnetic material, An excitation coil 1 for generating a magnetic field with alternating polarity, a giant magnetostrictive element 2 whose length is elastically changed by the strength of the magnetic field with alternating polarity by the excitation coil 1, and a part from an opening point 7a of the yoke 7 A movable part 3A from which 32A projects to the outside, and a pair of preload disc springs 4 for applying a preload to both sides of the giant magnetostrictive element 2 in the direction in which the length of the giant magnetostrictive element 2 changes elastically, are provided inside the yoke 7. I have.
[0044]
The exciting coil 1 and the giant magnetostrictive element 2 are constituted by two sets of exciting coils 1A, 1B and giant magnetostrictive elements 2A, 2B provided on both sides of the remaining portion 31A of the movable part 7, and each preload disk spring 4 is connected to the yoke 7. Are fixed to the inner wall of each of the two magnetostrictive elements 2A and one end of the other magnetostrictive element 2B, so that the movable part 3A is close to the end of its own remaining part 31A and the two supersets. The structure is sandwiched between the magnetostrictive elements 2A and 2B.
[0045]
Here, the giant magnetostrictive elements 2A and 2B are excited so that when one of the giant magnetostrictive elements is extended, the other giant magnetostrictive element is contracted. Accordingly, the movable portion 3A moves in the expansion / contraction direction according to the expansion / contraction of the two giant magnetostrictive elements. The point of the remaining part 31A of the movable part 3A that is in contact with each giant magnetostrictive element is the operating point, and the tip of the part 32A of the movable part 3A is the working point. The distance between the opening point (fulcrum) 7a and the action point is set longer than the distance between the opening point (fulcrum) 7a and the operating point.
[0046]
In the giant magnetostrictive linear actuator having such a structure, the movable portion 3A reciprocates by alternately energizing the two sets of exciting coils 1A and 1B. A driving force is generated by the magnetostrictive element. Moreover, since it is a substantially closed magnetic circuit structure, high efficiency can be achieved.
[0047]
In the sixth embodiment, the magnetic bias is not applied. However, the magnetic bias may be applied by a magnet or a direct current. When a magnetic bias is applied, the movable part moves at the same frequency as the excitation current.
[0048]
Further, the overall structure of the yoke is not limited to a box shape as shown in FIG. 17, but may be a C-shaped cylindrical shape.
[0049]
【The invention's effect】
As is apparent from the above, according to the first aspect of the present invention, the length is elastic depending on the excitation coil for generating a magnetic field with alternating polarity and the strength of the magnetic field with alternating polarity by the excitation coil. A changing giant magnetostrictive element, a pair of movable parts respectively provided on both sides of the giant magnetostrictive element in the direction in which the length of the giant magnetostrictive element elastically changes, and a preload to the giant magnetostrictive element side with respect to the pair of movable parts And both ends of the giant magnetostrictive element are in contact with both movable parts near the fulcrum between one end and the other end, which are the action points of each movable part, so that the vibration direction of the action point of the movable part And the expansion / contraction direction of the giant magnetostrictive element coincide with each other, and the pair of movable parts move in opposite directions, so that the vibration caused by each movement is canceled and a giant magnetostrictive linear actuator with small vibration is realized. Door can be.
[0050]
According to a second aspect of the present invention, in the giant magnetostrictive linear actuator of the first aspect, the exciting coil and the giant magnetostrictive element are constituted by two sets of exciting coils and giant magnetostrictive elements provided on both sides of the fixed member, One end of the pair of giant magnetostrictive elements and one end of the other pair of giant magnetostrictive elements are in contact with the pair of movable parts, respectively, and vibration is reduced even in this structure.
[0051]
According to a third aspect of the present invention, in the giant magnetostrictive linear actuator according to the second aspect, the additional means applies the preload to the giant magnetostrictive element closer to the fulcrum than the part of each movable part where both ends of the giant magnetostrictive element are in contact. since adding the position, Te this principle can be used to amplify preload, the width of the adjustment is increased.
[0052]
According to a fourth aspect of the present invention, in the giant magnetostrictive linear actuator according to the first or second aspect, the pair of movable parts are supported on the other end sides thereof, and the exciting coil and the giant magnetostrictive element between the pair of movable parts. And a magnetic member provided between the pair of movable parts and facing the support via an exciting coil and a giant magnetostrictive element between the pair of movable parts, and the pair of movable parts and the support body are magnetic bodies. Yes, because the magnetostrictive element, the pair of movable parts, the support, and the magnetic member form a closed magnetic path, the magnetic resistance of the magnetic circuit is reduced compared to the open magnetic path, and the alternating magnetic field required to expand and contract the giant magnetostrictive element Since the current for generating the current can be suppressed, high efficiency can be achieved.
[0053]
According to a fifth aspect of the present invention, in the giant magnetostrictive linear actuator according to the fourth aspect, the magnetic member moves in a pair perpendicular to the plane including the direction of motion of the pair of movable parts via a certain gap. Since it arrange | positions so that a part may be opposed , high efficiency can be aimed at stably.
[0054]
According to the sixth aspect of the present invention, there is provided a yoke having a C-shaped cross section having one opening point made of a magnetic material, an exciting coil for generating a magnetic field having alternating polarity, and the exciting coil. A giant magnetostrictive element whose length elastically changes depending on the strength of a magnetic field with alternating polarity, a movable part partially protruding outside from the opening point of the yoke, and a super magnetostrictive element in the direction in which the length of the giant magnetostrictive element changes elastically An additional means for applying a preload on both sides of the magnetostrictive element is provided inside the yoke, and the excitation coil and the giant magnetostrictive element are composed of two sets of excitation coils and a giant magnetostrictive element provided on both sides of the remaining part of the movable part, The additional means is fixed to the inner wall of the yoke and applies a preload to one end of one set of super magnetostrictive elements and one end of the other set of super magnetostrictive elements. Depending on the element Since the movable portion reciprocates by energizing the two excitation coils alternately, the reverse driving force is generated by the giant magnetostrictive element regardless of which direction the movable portion is moving. A giant magnetostrictive linear actuator with small vibration can be realized. Moreover, since it is a closed magnetic circuit structure, high efficiency can be achieved.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a giant magnetostrictive linear actuator according to a first embodiment of the present invention.
FIG. 2 is a configuration diagram of a giant magnetostrictive linear actuator according to a second embodiment of the present invention.
FIG. 3 is a configuration diagram of a giant magnetostrictive linear actuator according to a third embodiment of the present invention.
FIG. 4 is a configuration diagram of a giant magnetostrictive linear actuator according to a fourth embodiment of the present invention.
FIG. 5 is an explanatory diagram of a closed magnetic circuit, which is a feature of the giant magnetostrictive linear actuator.
FIG. 6 is an explanatory diagram of a closed magnetic circuit serving as a comparative reference of the giant magnetostrictive linear actuator.
7 is a diagram showing a structure when the magnetic path bypass in FIG. 4 is provided in the giant magnetostrictive linear actuator of FIG. 2;
FIG. 8 is an explanatory diagram of a closed magnetic circuit, which is a feature of the giant magnetostrictive linear actuator.
FIG. 9 is an explanatory diagram of a closed magnetic circuit serving as a comparative reference of the giant magnetostrictive linear actuator.
FIG. 10 is an external view of a giant magnetostrictive linear actuator according to a fifth embodiment of the present invention.
FIG. 11 is a configuration diagram of the giant magnetostrictive linear actuator.
FIG. 12 is a view of the same giant magnetostrictive linear actuator as viewed from the output unit side.
13 is an external view when the magnetic path bypass in FIGS. 10 to 12 is provided in the giant magnetostrictive linear actuator of FIG.
FIG. 14 is a configuration diagram of the giant magnetostrictive linear actuator.
FIG. 15 is a view of the same giant magnetostrictive linear actuator as viewed from the output side.
FIG. 16 is a diagram showing a structure example of another magnetic path bypass.
FIG. 17 is an external view of a giant magnetostrictive linear actuator according to a sixth embodiment of the present invention.
FIG. 18 is a configuration diagram of the giant magnetostrictive linear actuator.
FIG. 19 is a configuration diagram of a conventional giant magnetostrictive actuator.
FIG. 20 is a view showing a flow of magnetic flux of the giant magnetostrictive actuator.
FIG. 21 is a configuration diagram of a giant magnetostrictive linear actuator proposed in Japanese Patent Application No. 2001-262875.
FIG. 22 is a configuration diagram of a giant magnetostrictive linear actuator that realizes the counter operation proposed in Japanese Patent Application No. 2001-262875.
[Explanation of symbols]
1, 1A, 1B Excitation coil 2, 2A, 2B Super magnetostrictive element 3, 3A Movable part 4 Preload disc spring 4A Preload addition member 42A Preload addition spring 5 Support body 52 Fixing member 6, 6A, 6B Magnetic path bypass 7 York

Claims

An exciting coil for generating a magnetic field with alternating polarity, a giant magnetostrictive element whose length changes elastically according to the strength of the magnetic field with alternating polarity by the exciting coil, and a direction in which the length of this giant magnetostrictive element changes elastically And a pair of movable parts respectively provided on both sides of the giant magnetostrictive element, and additional means for applying a preload to the pair of movable parts toward the giant magnetostrictive element side, and one end serving as an action point of each movable part A giant magnetostrictive linear actuator characterized in that both ends of the giant magnetostrictive element are in contact with both movable parts near the fulcrum between the ends.

The exciting coil and the giant magnetostrictive element are constituted by two sets of exciting coils and giant magnetostrictive elements provided on both sides of the fixed member, and one pair of one set of giant magnetostrictive elements and the other set of giant magnetostrictive elements are paired. The giant magnetostrictive linear actuator according to claim 1, wherein each of the movable parts is in contact with each other.

3. The giant magnetostrictive linear actuator according to claim 2 , wherein the adding means adds a preload to the giant magnetostrictive element to a position closer to the fulcrum than a portion of each movable portion where both ends of the giant magnetostrictive element are in contact .

A pair of movable parts are supported on the other end side of each of these, and a support body that supports the excitation coil and the giant magnetostrictive element between the pair of movable parts, and an excitation coil and a superstructure provided between the pair of movable parts. A magnetic member facing the support via the magnetostrictive element, the pair of movable parts and the support are magnetic bodies, and the super magnetostrictive element, the pair of movable parts, the support and the magnetic member form a closed magnetic path The giant magnetostrictive linear actuator according to claim 1 or 2, wherein

5. The giant magnetostriction according to claim 4 , wherein the magnetic member is disposed so as to face the pair of movable parts via a certain gap in a direction orthogonal to a plane including the movement direction of the pair of movable parts. Linear actuator.

A yoke having a C-shaped cross section with a single opening point made of a magnetic material is provided, and an excitation coil for generating a magnetic field with alternating polarity, and a length depending on the strength of the magnetic field with alternating polarity by the excitation coil. A pre-load is applied to both sides of the magnetostrictive element in a direction in which the length of the super magnetostrictive element changes elastically. And the exciting coil and the giant magnetostrictive element are composed of two sets of exciting coil and giant magnetostrictive element provided on both sides of the remaining part of the movable part, and the adding means is fixed to the inner wall of the yoke. A preload is applied to one end of one set of giant magnetostrictive elements and one end of the other set of giant magnetostrictive elements, and the movable part is sandwiched between the two sets of giant magnetostrictive elements near the front end of the remaining part. Do Magnetostrictive linear actuator.