JP4066040B2

JP4066040B2 - Electromagnet and operation mechanism of switchgear using the same

Info

Publication number: JP4066040B2
Application number: JP2001249325A
Authority: JP
Inventors: 歩森田; 安昭鈴木; 雅人薮; 徹谷水; 易蔵柴田; 孝志門脇; 智之紀井
Original assignee: Hitachi Engineering and Services Co Ltd; Hitachi Ltd
Current assignee: Hitachi Engineering and Services Co Ltd; Hitachi Ltd
Priority date: 2001-01-18
Filing date: 2001-08-20
Publication date: 2008-03-26
Anticipated expiration: 2021-08-20
Also published as: JP2002289430A

Description

【０００１】
【発明の属する技術分野】
本発明は、電磁石及びそれを用いた開閉装置の操作機構の構成に関するもので、特に永久磁石の減磁を抑制した電磁石とそれを適用した信頼性の高い開閉装置の操作機構に関する。
【０００２】
【従来の技術】
開閉装置の操作機構には、電動バネ操作機構、油圧式および空気圧式操作機構などがある。通常これらの操作機構は、部品数が多く、リンク機構が複雑になるために比較的高い製造コストが伴う。リンク機構を簡素化する手法の一つに電磁石を利用した操作機構があり、例えば特開平５−２３４４７５号公報に記載された真空接触器では電磁石を投入動作に使用し、投入と同時に蓄勢された遮断バネを解放して接点を開離する。また、特表平１０−５０５９４０号に記載された操作機構では、投入および遮断用の２個のコイルを貫通するプランジャを設けて、投入・遮断の両方の動作を電磁石で行っている。また、特開２０００−２４９０９２号公報では、永久磁石の吸引力を利用して投入状態を維持し、コイル電流で逆励磁することによって個別に設けた可動部材駆動用バネで遮断動作を行っている。この場合、コイルは投入用・遮断用の区別なく単一コイルで済む利点がある。
【０００３】
【発明が解決しようとする課題】
しかし、従来の永久磁石付き電磁石には下記の欠点があった。永久磁石には、希土類のサマリウム−コバルト系磁石とネオジウム系磁石，アルニコ系磁石，フェライト系磁石などが存在する。残留磁束密度が高く、かつコストが比較的安価なネオジウム系磁石を用いると、電磁石を小形で安価にできる。しかし、ネオジウム系磁石は保持力が１０００ｋＡ／ｍと大きく、着磁磁界は２０００ｋＡ／ｍ（磁束密度２.５Ｔ相当）以上必要である。それゆえ、組み込まれた電磁石のコイルで永久磁石を着磁することは現実的に不可能で、着磁後の磁石を組み込まなければならない。
【０００４】
電磁石を開閉装置の操作機構に適用する場合、２０年以上の長期にわたる動作保証と、１万回以上の多数回動作を満足する必要がある。したがって、永久磁石を減磁させる要因をできるだけ排除しなければならない。特開2000−249092号公報に記載される永久磁石付き電磁石では、永久磁石に直接、逆方向磁界を印加して遮断動作を行っている。永久磁石に逆エネルギーを繰り返し与えることによって、減磁、すなわち寿命が低下する危険性がある。
【０００５】
さらに、磁路内に永久磁石が存在すると、コイルから見た磁気抵抗は大きくなる。永久磁石の透磁率は空気と同程度であるため、動作開始時点ではストローク長に永久磁石の厚みを加えたギャップが存在することになってしまい、より大きなアンペアターンを必要とする。
【０００６】
また、永久磁石の厚さ、鉄心には製造段階で生ずる寸法誤差が避けられず、この寸法誤差により、永久磁石とこれに対向して進退する可動鉄心の間のストローク端でのギャップは変化する。そして、このギャップにより投入特性、遮断特性及び投入状態保持力（吸着力）が変化する。しかし、特性を安定させるために前記寸法誤差の許容値、すなわち公差を厳しく管理すると、安価な電磁石製作のネックとなる。
【０００７】
本発明は上記課題を解決する手段として考案したもので、その目的とするところは、永久磁石を直接逆励磁することなく、かつコイル電流が作る磁路中に永久磁石が存在しない長寿命で高効率な電磁石、およびこの電磁石を用いた開閉装置の操作機構を提供することにある。本発明の他の目的は、永久磁石とそれに対向して進退する可動鉄心の間隔を調整することが容易な電磁石とすることにある。
【０００８】
【課題を解決するための手段】
すなわち本発明は、コイル３と、前記コイル３の中心軸上を移動する可動鉄心１と、前記コイル３の上面、下面、および外周面に設けた固定鉄心２で構成され、前記可動鉄心１と前記固定鉄心２で囲まれた空隙に永久磁石１２を配置し、前記永久磁石１２が発生する磁界によって前記可動鉄心１を前記固定鉄心２に吸着させる電磁石であって、前記固定鉄心は、前記コイルの下面側に設けられて中央部に前記コイルと同心の円形の開口を持つ第１の角形平板２ｆと、前記第１の角形平板２ｆの上面に載置されて前記コイルの外周面を覆う同心の鋼管２ｅと、前記鋼管２ｅの上端に載置して前記コイルの上面側に設けられて中央部に前記コイルと同心の円形の開口を持つ第２の角形平板２ｄとを備えて構成され、前記第２の角形平板の上面には永久磁石が配置され、前記可動鉄心は、前記永久磁石を挟んで前記第２の角形平板の上面に対向する面を備える円筒平板と、前記コイルの内周面に対向する円筒面を備えるプランジャ部材とで構成され、前記プランジャ部材の前記円筒平板側の端面と前記円筒平板の間に薄板の磁性部材が介装されてなり、前記第２の角形平板の内周面と前記プランジャ部材の円筒面との間隔ｇ１が、前記永久磁石の軸方向の厚さｔよりも小さいことを特徴とする電磁石１０である。
【０００９】
上記電磁石において、前記第２の角形平板の上面に前記鋼管と同心に配置された円筒と、この円筒の上面に積み重ねられた第３の角形平板とを備え、両端にねじ部を設けたロッドを前記第１の角形平板と第２の角形平板と第３の角形平板に貫通させて、ロッドの両端のねじ部をナットで締め付けて構成されるようにしてもよい。
【００１１】
上記の電磁石において、前記コイル３に順方向および逆方向に電流を選択的に流すことのできる電源回路を備え、順方向に電流を流した時に前記永久磁石１２が発生する磁界と同方向の磁界を発生させて吸引動作を行い、逆方向に電流を流した時に前記永久磁石が１２が発生する磁界を打ち消して釈放動作を行う。
【００１２】
また、本発明は、コイルと、前記コイルの中心軸上を移動する可動鉄心と、前記コイルの軸方向両端面及び外周面に設けた固定鉄心と、前記コイルに順方向及び逆方向に電流を流すことのできる電源と、を含んで構成され、前記コイルに順方向に通電したとき前記可動鉄心を前記固定鉄心に向かって移動させる電磁石において、前記固定鉄心は前記コイルの軸方向の一方の端面を覆うように設けられた固定鉄心上部部材を含んでなり、前記固定鉄心上部部材の上面には永久磁石が配置され、前記可動鉄心は、前記永久磁石を挟んで前記固定鉄心上部部材の上面に対向する面を備える円筒平板と、前記コイルの内周面に対向する円筒面を備えるプランジャ部材とを含んで構成され、かつ、前記固定鉄心は、前記コイルの軸方向の一方の端面に設けられて中央部に前記コイルと同心の円形の開口を持つ第１の角形平板と、軸方向一方の端面を前記第１の角形平板に対向させて配置されて前記コイルの外周面を覆う鋼管と、前記鋼管の軸方向他方の端面に対向して前記コイルの軸方向他方の端面に設けられ中央部に前記コイルと同心の円形の開口を持つ第２の角形平板とを備えて構成され、前記プランジャ部材の前記円筒平板側の端面と前記円筒平板の間に薄板の磁性部材が介装されてなり、前記第２の角形平板の内周面と前記プランジャ部材の円筒面との間隔ｇ１が、前記永久磁石の軸方向の厚さｔよりも小さいことを特徴とする。
【００１４】
前記永久磁石は、希土類のサマリウムーコバルト系磁石とネオジム系磁石、アルニコ系磁石、フェライト系磁石を含む永久磁石の内から選択されたものとすればよい。
【００１５】
さらに、本発明は、上記の電磁石と、接離自在な接点と、前記接点を開極するための遮断バネを備え、前記電磁石の前記コイル３に順方向および逆方向の電流を選択的に流すことができる電源回路を設け、順方向に電流を流した時に前記遮断バネを蓄勢しながら接点を投入し、前記永久磁石１２の吸引力によって投入状態を維持し、前記コイル３に逆方向の電流を流す時に前記永久磁石１２の作る磁束を打ち消して、前記遮断バネの力で遮断する開閉装置の操作機構である。
【００１６】
前記操作機構に用いる電磁石は、開閉装置の容量に応じて、同一のものを複数個組み合わせて用いるようにするのが望ましい。
【００１７】
すなわち、このように構成された電磁石であると、切動作時、前記コイルに逆方向に電流を流すことによりできる磁界が永久磁石を貫かないため、永久磁石を直接逆励磁することなく、かつコイル電流が作る磁路中に永久磁石が存在しないため、永久磁石を減磁する要因はなくなり、ネオジム系の永久磁石を使用することも可能であり、長寿命で効率の優れた電磁石を提供できる。
【００１８】
また、前記プランジャ部材の前記円筒平板側の端面と前記円筒平板の間に、磁性部材を介装することにより、この磁性部材の厚さを変えるか、この磁性部材を薄板材で構成し、薄板材の枚数を変えることで、永久磁石とそれに対向して進退する可動鉄心の、可動鉄心のストローク端におけるギャップを容易に調整できる。すなわち、部品の公差を厳しくしないでも特性を安定させることができ、安価で信頼性の高い電磁石を提供できる。さらに、この電磁石を開閉装置の操作機構を適用することによって、小型・安価でさらに信頼性の高い開閉装置を実現できるようになる。
【００１９】
【発明の実施の形態】
本発明の参考例に関し、図１ないし図１６を用いて説明する。
【００２０】
（参考例１）
本発明の参考例１について図１ないし図５を用いて説明する。
【００２１】
図１は、本発明の参考例１である電磁石１０の断面図である。電磁石１０は軸対称構造で、図の右半分に構造説明のための記号を付加し、左半分には永久磁石１２およびコイル３を流れる電流が作る磁界Ｂ（鎖線）を示した。
【００２２】
可動鉄心１は、コイル３の中心軸上を貫通するプランジャ５と、その端部に固定した円盤状の鋼板６で構成し、プランジャ５の端部に固定した非磁性の接続部材７によって負荷Ｗに接続する。負荷Ｗは、電磁石１０の吸引状態にて可動鉄心１を上方向へ駆動しようとする力を作用させる。固定鉄心２は、いずれも磁性体である鋼管２ａ，凸型鋼材２ｂ、およびリング状の鋼板２ｃで構成する。凸型鋼材２ｂおよびリング状の鋼板２ｃは、図示したように鋼管２ａの両端からねじ込む要領で取り付けてもよいし、あるいは溶接にて固定してもよい。また、鋼管２ａと凸型鋼材２ｂ、あるいは鋼管２ａとリング状の鋼板２ｃは円柱状の材料から切削して製作してもよい。ここで、鋼材２ｂは凸型形状としたが、勿論単純な平板でも構わない。ただし、プランジャ５の端面と固定鉄心２のギャップＸをコイル３の中央付近に設けると、漏れ磁束が低減することが分かっており、凸型鋼材を用いた方がよい。また、凸型鋼材２ｂは、一体物で製作してもよいし、あるいは２枚の鋼板を接続して構成してもよい。コイル３は、絶縁物あるいは非磁性体金属（アルミ，銅など）で製作されたボビン３ａと、巻線３ｂで構成する。
【００２３】
リング状の鋼板２ｃは、比較的深めに鋼管２ａにねじ込み、磁性体の突出部４を設けた形となっている。本参考例の電磁石１０は、プランジャ５の端面と凸型鋼材２ｂ，円盤状の鋼板６と突出部４がそれぞれ同方向に対向する構造となっている。プランジャ５の側面とリング状の鋼板２ｃ間の距離ｇは、可動鉄心のストローク長よりも短くした。この理由については後述する。また、プランジャ５の端面と凸型鋼材２ｂ間の距離Ｘは、円盤状の鋼板６と突出部４間の距離Ｌに比べて短くし、吸引動作完了時にはプランジャ５と凸型鋼材２ｂが接触する状態になる。
【００２４】
リング状の永久磁石１２は、プランジャ５，円盤状の鋼板６，突出部４、およびリング状の鋼板２ｃで囲まれた領域に配置し、リング状の鋼板２ｃ上に固定してある。符号１３は、例えばＳＵＳなどの非磁性体で製作した永久磁石１２の抑え金具であり、抑え金具１３は鋼管２ａにねじ込む要領で固定してある。抑え金具１３によって、永久磁石１２と突出部４の間に間隙を設けているが、これは、永久磁石１２の作る磁束が突出部４によって短絡するのを防止するためである。
【００２５】
本参考例の電磁石１０の動作について、図２ないし図５を用いて説明する。図２は吸引動作開始直後の状態、図３は吸引動作完了直前の状態、図４は吸引動作完了後の状態、および図５は釈放動作中の状態を表す。
【００２６】
外部の電源回路（図示せず）によってコイル３を通電すると、プランジャ５の端面に吸引力Ｆ０が働き、可動鉄心１は下方向に動作開始する。ここで、プランジャ５の側面とリング状の鋼板２ｃ間の距離ｇは、可動鉄心１のストローク長よりも短く設定しているため、コイル電流が作る磁界Ｂｃは経路Ｏ１を通る。ここで、磁界Ｂｃと永久磁石１２が発生する磁界Ｂｍの方向は、図２の矢印の向きになるように、コイル電流の方向と永久磁石１２の極性をあらかじめ設定しておく必要がある。なお、磁界Ｂｃと磁界Ｂｍの向きは、同時に逆方向になっていてもよい。
【００２７】
吸引力Ｆ０によって可動鉄心１が駆動されると、やがて図３に示す状態になる。可動鉄心１の移動に伴って、円盤状の鋼板６と突出部４間のギャップＬが減少し、プランジャ５とリング状の鋼板２ｃ間のギャップｇよりも短くなる(ｇ＞Ｌ)。それゆえ、コイル電流による磁界Ｂｃは経路Ｏ２に分流し始め、動作完了時にはそのほとんどが経路Ｏ２を流れる。すなわち、可動鉄心１の移動に伴い、プランジャ５端面に働く吸引力Ｆ０に加えて、円盤状の鋼板６と突出部４間にも吸引力Ｆ１が作用する。なお、吸引動作完了直前の状態では、永久磁石１２の磁界Ｂｍが経路Ｏ３を通るため、吸引力Ｆ０は更に大きくなる。
【００２８】
可動鉄心１の動作が完了した後、コイル３の電流を切ると、永久磁石１２の吸引力によって吸引状態が保持される。吸引動作完了後も円盤状の鋼板６と突出部４間にはギャップが存在するため、永久磁石１２のつくる磁場Ｂｍは経路Ｏ３を通る。吸引力Ｆ０により、可動鉄心１と固定鉄心２の吸着状態が維持される。
【００３９】
釈放動作について図５を用いて説明する。釈放動作は、吸引動作時と逆向きの電流をコイル３に通電して行う。コイル電流が作る磁界Ｂｃは経路Ｏ２を流れ、永久磁石１２の作る磁界Ｂｍを打ち消す。プランジャ５の端面に作用する吸引力Ｆ０が低減し、負荷力によって可動鉄心１は上向きに移動する。ただし、磁界Ｂｃによって、円盤状の鋼板６と突出部４間に吸引力Ｆｒが同時に働くため、過大な電流をコイル３に通電すると再び吸引動作する可能性がある。負荷力とのバランスによってコイル電流を制限し、かつ釈放動作完了後は即時にコイル電流を遮断する手段を設ける必要がある。
【００３０】
次に、本参考例の効果について説明する。従来の永久磁石付き電磁石は、コイル電流が作る磁路中に永久磁石１２が存在するため、釈放動作時には直接永久磁石１２を逆励磁していた。繰り返し動作によって永久磁石１２に逆エネルギーを与え続けると、減磁する危険性がある。本参考例の電磁石では、永久磁石１２を可動鉄心１および固定鉄心２で囲まれた空隙に配置、すなわち磁気シールドされた領域に配置したため、コイル電流の作る磁界Ｂｃが直接永久磁石１２に作用することはない。釈放動作においても永久磁石１２に逆エネルギーを与えることはない。減磁の危険性が回避され、長寿命で信頼性の高い電磁石となる。
【００３１】
また、永久磁石１２の透磁率は空気とほぼ同じで、コイル電流が作る磁路中に永久磁石１２が存在すると、コイルからみた磁気抵抗が大きくなる。動作開始時には、ストロークに永久磁石１２の厚みを加えた分のギャップが存在することになり、動作に必要なアンペアターンが増加する。本実施例の電磁石１０では、永久磁石はコイル電流が作る磁路中に存在しないため、磁気抵抗が小さく効率がよい。
【００３２】
（参考例２）
本発明の参考例２について図６および図７を用いて説明する。
【００３３】
図６は本発明の参考例２である電磁石１０の断面図である。可動鉄心１は、コイル３の中心軸上を貫通するプランジャ５と、その端部に固定した円盤状の鋼板６で構成し、プランジャ５の端部に固定した非磁性の接続部材７によって負荷と接続する。固定鉄心２は、いずれも磁性体である鋼管２ａ，凸型鋼材２ｂ、およびリング状の鋼板２ｃで構成する。凸型鋼材２ｂおよびリング状の鋼板２ｃは、図示したように鋼管２ａの両端からねじ込む要領で取り付けてもよいし、あるいは溶接にて固定してもよい。凸型鋼材２ｂは、一体物で製作してもよいし、あるいは２枚の鋼板を接続して構成してもよい。コイル３は、絶縁物あるいは非磁性体金属（アルミ，銅など）で製作されたボビン３ａと、巻線３ｂで構成する。
【００３４】
リング状の永久磁石１２は、リング状の鋼板２ｃ上に固定する。符号１５は、例えばＳＵＳなどの非磁性部材で製作したパイプであり、永久磁石１２を挟持した状態にて鋼管２ａに固定する。パイプ１５には大きな力がかからないので、ネジ１６などで固定すればよい。パイプ１５を非磁性部材で製作するのは、永久磁石１２の磁界がパイプ１５で短絡するのを回避するためである。また、パイプ１５の端部には非磁性部材で製作したふた１７が取り付けてあり、可動鉄心１に固定したロッド８が貫通する。ふた１７，凸型鋼材２ｂ，接続部材７、およびロッド８によって可動鉄心１の軸ずれを防止する。
【００３５】
プランジャ５の端面と凸型鋼材２ｂ間の距離Ｘは、円盤状の鋼板６と永久磁石１２間の距離Ｌに比べて短くしてあり、円盤状の鋼板６が衝突して永久磁石１２が破壊するのを回避する。
【００３６】
本参考例の電磁石１０の動作について、図６ないし図９を用いて説明する。図６ないし図９は、電磁石１０の断面を示し、右半分に構造を説明するための符号、左半分には磁界の様子を付加してある。
【００３７】
図６は、吸引動作開始直後の状態を示す。プランジャ５の端面と凸型鋼材２ｂ間の距離Ｘ，円盤状の鋼板６と永久磁石１２の距離Ｌはともに、永久磁石１２とプランジャ５間の距離ｇより長く、永久磁石１２の作る磁界Ｂｍは、図６に示すように永久磁石１２の周辺にしか及ばない。それゆえ、可動鉄心１には働く駆動力は非常に弱い。外部の電源回路（図示せず）からコイル３を通電すると、コイル電流による磁界Ｂｃにより、プランジャ５の端面に吸引力Ｆ０が働き、可動鉄心１は下方向に動作開始する。ここで、プランジャ５の側面とリング状の鋼板２ｃ間の距離ｇは、可動鉄心１のストローク長よりも短く設定しているため、コイル電流が作る磁束Ｂｃは経路Ｏ４を通る。コイル電流による磁界Ｂｃと永久磁石１２の磁界Ｂｍの方向が図６に示す矢印の向きになるように、コイル電流の方向と永久磁石１２の極性方向をあらかじめ設定しておく必要がある。なお、磁界Ｂｃと磁界Ｂｍの向きが同時に逆になっていてもよい。
【００３８】
吸引力Ｆ０によって可動鉄心１が駆動されると、やがて図７に示す状態になる。可動鉄心１の移動に伴って、円盤状の鋼板６と永久磁石１２間のギャップＬが減少し、プランジャ５とリング状の鋼板２ｃ間のギャップｇよりも短くなるため（ｇ＞Ｌ）、永久磁石１２の磁界Ｂｍは経路Ｏ５を通る。すなわち、可動鉄心１の移動が進むにつれて、プランジャ５の端面に作用する吸引力Ｆ０とともに、円盤状の鋼板６と永久磁石１２間にも吸引力Ｆ１が働く。また、永久磁石１２の磁界Ｂｍがプランジャ５と凸型鋼材２ｂの対向面を通るため、吸引力Ｆ０も更に大きくなる。
【００３９】
可動鉄心１の動作が完了した後、コイル３の励磁をとくと、永久磁石１２の磁束Ｂｍにより吸引力Ｆ０および吸引力Ｆ１が働き、この状態が保持される。
【００４０】
一方、釈放動作は、図８に示すように、吸引動作時と逆向きの電流をコイル３に通電して行う。コイル電流が作る磁界Ｂｃは経路Ｏ６を流れ、永久磁石１２の作る磁界Ｂｍを打ち消す。吸引力Ｆ０は低減し、負荷力によって可動鉄心１は上向きに移動する。
【００４１】
本参考例の効果について説明する。参考例１の電磁石と同様に、コイル電流の作る磁界Ｂｃが直接永久磁石１２に作用せず、釈放動作時も逆エネルギーを与えることはない。それゆえ、永久磁石減磁の危険性が回避され、長寿命で信頼性の高い電磁石となる。また、永久磁石１２の透磁率は空気とほぼ同じで、コイル電流が作る磁路中に永久磁石１２が存在すると、コイルからみた磁気抵抗が大きくなる。動作開始時には、ストロークに永久磁石１２の厚みを加えた分のギャップが存在することになり、必要なアンペアターンが増加する。本実施例の電磁石１０では、永久磁石はコイル電流が作る磁路中に存在しないため、磁気抵抗が小さく効率がよい。
【００４２】
さらに、本参考例の電磁石は、下記の効果を有する。釈放動作において、参考例１の電磁石は、コイル電流が作る磁界Ｂｍによって、円盤状の鋼板６と磁性体突出部４間に吸引力Ｆ１が作用するため、過大な電流をコイル３に通電すると再び吸引動作する可能性があった。それゆえ、負荷力とのバランスによってコイル電流を制限し、かつ釈放動作完了後は即時にコイル電流を遮断する手段を設ける必要があった。しかし、本参考例の電磁石ではコイル電流による磁界Ｂｃで吸引力を発生する部分はなく、再び吸引動作することはない。それゆえ、負荷力とのバランスによってコイル電流を制限したり、かつ釈放動作完了後に即時にコイル電流を遮断する手段を設ける必要はない。
【００４３】
（実施例１）
本発明の実施例１について図９（入状態）および図１０（切状態）を用いて説明する。図９、図１０は本発明の実施例である電磁石１０の断面図であり、図９が、開閉装置に結合したとき開閉装置が入状態のときの電磁石を示し、図１０が、開閉装置に結合したとき開閉装置が切状態のときの電磁石を示す。以下の説明における入状態、切状態は、いずれも、電磁石を開閉装置に結合したとき、開閉装置が入状態あるいは切状態のときの電磁石の状態をいう。
【００４４】
コイル３は、絶縁物あるいは非磁性体金属（アルミ、銅など）で製作されたボビン３ａと、巻線３ｂからなっている。
【００４５】
図示の電磁石１０は、コイル３と、前記コイル３の中心軸上を移動する磁性体からなる可動鉄心と、前記コイル３の軸方向両端面及び外周面を覆うように設けた磁性体からなる固定鉄心と、前記コイル３に順方向及び逆方向に電流を流すことのできる図示されていない電源と、を含んで構成されている。前記コイル３に順方向に通電したとき前記可動鉄心を前記固定鉄心に向かう方向、すなわち、図上、右から左に向かって移動させるようになっている。なお、以下の説明では、便宜上、図９の向かって右側を上側、左側を下側として方向を示す。
【００４６】
前記固定鉄心は、前記コイル３の軸方向の一方の端面を覆うように設けられ、中央部に前記コイル３と同心の円形の開口を持つ固定鉄心上部部材である第２の角形平板２ｄと、前記コイルの軸方向の他方の端面を覆うように設けられ中央部に前記コイル３と同心の円形の開口を持つ固定鉄心下部部材である第１の角形平板２ｆと、前記第２の角形平板２ｄと第１の角形平板２ｆの間に挟持され、前記コイル３の外周面を覆う鋼管２ｅと、前記第１の角形平板２ｆの上面に、前記鋼管２ｅと同心に配置された円筒２ｇ、とを含んで構成されている。第２の角形平板２ｄ、第１の角形平板２ｆ、鋼管２ｅ、及び円筒２ｇは全て磁性体であり、第１の角形平板２ｆと円筒２ｇは、ねじ等で固定されるか、一体に溶接されている。もちろん、一つの材料から削り出したものであってもよい。
【００４７】
前記第２の角形平板２ｄの上面には中心に開口を設けた円板状の永久磁石１２が吸着、配置され、接着剤により固定されている。永久磁石１２は、ネオジム系、サマリウム系、アルニコ系、ネオジムボンド系、フェライト系のいずれの材質であってもよい。また、図示の永久磁石１２は、１個の円環状の磁石であるが、必ずしも連続した円環状をなしている必要はなく、四角形、円形など異なる平面形状のものを、分散して第２の角形平板２ｄの上面に配置してもよい。但しこの場合も、後述する円筒平板６ａに対向する面の面積が、所要の吸着力を発揮できる面積になるようにする必要がある。
【００４８】
前記可動鉄心は、前記第２の角形平板２ｄの前記開口、第１の角形平板２ｆの前記開口、鋼管２ｅ、及び円筒２ｇの各中心を挿通する非磁性のロッド１９と、このロッド１９に嵌め込まれて固着された円柱状の磁性体であるプランジャ５と、このプランジャ５の上側に磁性部材である薄板２１を介して配置され、前記ロッド１９に固着された磁性体である円筒平板６ａと、を含んで構成されている。円筒平板６ａの下面は、前記永久磁石１２を挟んで前記角形平板２ｄの上面に対向しており、前記プランジャ５の外周面は、前記コイル３の内周面に対向している。つまり、前記プランジャ５の外径は、前記コイル３の内径、永久磁石１２の中央の開口の径、及び角形平板２ｄの中央の開口の径のいずれよりも小さく、それらの内部を軸方向に移動可能になっているが、円筒平板６ａの外径は、永久磁石１２の中央の開口の径よりも大きく、円筒平板６ａは、永久磁石１２の中央の開口を通過できないようになっている。また、プランジャ５と円筒平板６ａは、ロッド１９に、ねじ込みまたは止め具で固着されている。
【００４９】
また、永久磁石１２の中央の開口と、第２の角形平板２ｄの中央の開口は同心、同径としてあり、永久磁石１２の軸方向の厚さｔは、第２の角形平板２ｄの中央の開口内周面と前記プランジャ５の外周面との間隔ｇ１よりも大きくしてある。
【００５０】
前記円筒２ｇの外径はコイル３の内径よりも小さく、前記プランジャ５の外径と同じにしてある。また、円筒２ｇの内径は、前記ロッド１９が自由に通過できる大きさにしてある。つまり、プランジャ５の下面は、円筒２ｇの上面に対向しており、可動鉄心が軸方向左側にに動くとき、その移動の限界は、プランジャ５の下面と円筒２ｇの上面が当接する点で決まる。
【００５１】
前記永久磁石１２の上側には、非磁性体（本実施例ではステンレス鋼を用いた）の管１５ａがコイル３と同心に配置され、管１５ａを永久磁石１２との間でサンドイッチ状に挟持する第３の角形平板１８が配置される。第３の角形平板１８は磁性体でも非磁性体でもよい。第１の角形平板２ｆ，第２の角形平板２ｄ，第３の角形平板１８の4隅または対角線上の2隅には、両端にねじを切った非磁性体であるロッド１４が通るように孔を開けてあり、ロッド１４の両端をナットで締めつけることによって全体を固定してある。
【００５２】
第３の角形平板１８、第１の角形平板２ｆには、コイル3と同心に前記ロッド１９が通る孔が形成され、この孔の部分にベアリングまたはドライベアリングを設けて前記ロッド１９が摺動するときの摩擦を低下させ、省メンテナンスを実現している。
【００５３】
図９の入状態は、永久磁石１２の吸引力（磁束φ１により生成）によって保持される。つまり、入状態は永久磁石１２の吸引力で、プランジャ５の下面と円筒２ｇの上面の間の空隙ｇ３が0の状態、すなわち、プランジャ５の下面が円筒２ｇの上面に当接した状態が保持される。プランジャ５の下面が円筒２ｇの上面に直接当接するのではなく、この間に薄い非磁性体を挟んでもよい。
【００５４】
電磁石組立て時、同一厚みの複数の薄板２１を用意しておき、プランジャ５と円筒平板６ａの間に挟む前記薄板２１の枚数を変えることにより、図9の状態で、永久磁石１２と円筒平板６ａの間に所望の大きさの空隙ｇ２が形成されるようにしてある。空隙ｇ２を作る理由は、入動作時、永久磁石１２に直接円筒平板６ａが衝突すると、永久磁石12が減磁し、永久磁石12の寿命が短くなるからである。
【００５５】
さらに、前記薄板２１の枚数を変えて、入状態での空隙ｇ２をできるだけ０に近づけることによって、磁気抵抗を小さくし、吸引力を大きくすることができる。この結果、永久磁石の厚さを薄くする、あるいは第２の角形平板２ｄに吸着する表面積を小さくすることで永久磁石１２の体積を減らしても、従来の吸引力を確保できる。したがって、体積に大きく依存する永久磁石のコストが低減され、小型で安価な電磁石を得ることができる。また、薄板２１の枚数を変えることで、入状態での空隙ｇ２の値を所望の一定値に近づけることができるので、入状態での永久磁石の吸引力、及び入切動作特性を安定させることができ、電磁石の信頼性を向上させることができる。
【００５６】
なお、同一厚みの薄板を複数枚用いて空隙の値を調整する代わりに、少しずつ厚さの異なる多種の厚さの板を用意しておき、その中の適切な厚さのものを1枚、あるいは異なる厚さのものを組み合わせて、前記空隙の値を調整するようにしてもよい。
【００５７】
次に図11（入動作時）、図12（切動作時）を用いて、入切動作について説明する。
【００５８】
図１１に示す入動作時、図示されていない電源から、コイル３に、永久磁石１２が作る磁界と同方向の磁界を作るように電流を流す（順方向の電流）。コイル電流及び永久磁石12により、それぞれ図１１に示す磁束φ２、φ１が生じ、円筒平板６ａを、図上左側に動かす吸引力、すなわち可動鉄心を固定鉄心に吸引する力が発生する。この吸引力は、プランジャ５と円筒２ｇの間の空隙、及び円筒平板６ａと永久磁石１２の間の空隙の双方で発生する。円筒平板６ａと永久磁石１２の間の空隙に発生する力をＦ１，プランジャ５と円筒２ｇの間の空隙に発生する力をＦ２とする。入動作時のＦ２は、磁束φ２と磁束φ１が合成された磁束によって生じる力である。
【００５９】
図１２に示す切動作時、前記図示されていない電源から、コイル３に、入動作時と逆方向の電流を流す。入状態保持時には、永久磁石が形成する磁束φ１により円筒平板６ａと永久磁石１２の間の空隙に発生する力Ｆ１と、磁束φ１によりプランジャ５と円筒２ｇの間の空隙に発生する力Ｆ２ａの和が、図示されていない遮断ばねによってロッド１９に図上右方向に加えられる力Ｆ０よりも大きくなっている。つまり、永久磁石１２の力が、遮断ばねの力に打ち勝って、入状態が保持されている。この状態で、前記逆方向の電流がコイル3に流されると、この電流により磁束φ１と逆方向の磁束φ５が形成され、この磁束φ５により、前記永久磁石１２の磁束φ１が弱められる。この弱められた磁束（あるいは磁束φ１と逆方向の磁束）によりプランジャ５と円筒２ｇの間の空隙に力Ｆ２ｂが発生する。Ｆ２ａ＞Ｆ２ｂであるから、可動鉄心に作用する図上左向きの力が小さくなり、Ｆ０＞（Ｆ１＋Ｆ２ｂ）となって、切動作が開始される。
【００６０】
このとき、永久磁石12の厚さｔは、第２の角形平板２ｄの中央の開口内周面と前記プランジャ５の外周面との間隔ｇ１よりも大きくしてあるから、逆電流により形成される磁束φ５は、図12に示すように、永久磁石１２を通過しない。これは、永久磁石12の透磁率が空気と同程度であるため、逆電流による磁束φ５は磁気抵抗の小さい、図12に示す磁路を取るためである。永久磁石に逆励磁を掛け続けると減磁する可能性があるが、本実施例の電磁石では、永久磁石に逆励磁がかかることがないので、減磁の生じる可能性が低下し、長寿命で信頼性の高い電磁石が得られる。
【００６１】
（実施例２）
本発明の実施例２について図１３および図１４を用いて説明する。
【００６２】
本実施例は、参考例１〜２、実施例１記載の電磁石１０を開閉装置の操作機構に適用したものである。図１３は、参考例２記載の電磁石１０を適用した三相真空遮断器２０の側断面図である。ここでは真空遮断器を例に説明するが、ガス遮断器などの他の開閉装置に本発明の電磁石１０を適用することも可能である。また、参考例２記載の電磁石１０を適用した例について述べるが、参考例１あるいは実施例１記載の電磁石も同様に適用可能である。
【００６３】
真空遮断器２０は、真空バルブ３０，操作機構部４０，絶縁架台３１、および制御回路５１・電磁石１０を収納する操作スペース５０で構成される。真空バルブ３０は紙面奥行き方向に３相分並んだ状態で設置してある。３つの真空バルブ３０は、操作機構部４０内のシャフト４１で連結してあり、単一の電磁石１０で駆動する。
【００６４】
真空バルブ３０は、上下の端板３２および絶縁筒３３からなる真空容器によって、その内部を真空状態に保つ。真空バルブ３０内に固定接点３７と可動接点３８を配置し、その接離によって投入および遮断を実現する。固定接点３７は、固定導体３５に固定してあり、固定側フィーダ３９と電気的に接続する。一方、可動接点３８は、可動導体３６に固定し、フレキシブル導体６１を介して可動側フィーダ６２に接続する。ベローズ３４は、その両端を可動導体３６および端板３２に接続する。ベローズ３４によって真空状態を維持したまま、固定接点３７と可動接点３８の接離が可能になる。
【００６５】
真空バルブ３０と電磁石１０はともにシャフト４１に連結しており、電磁石１０の発生する駆動力を可動導体３６に作用させる。可動導体３６は、絶縁ロッド６３によって操作機構と電気的に絶縁され、シャフト４１に固定したレバー４２に連結される。電磁石１０の可動鉄心１は、接続部材９によってレバー４４と連結する。
【００６６】
投入動作では、接圧バネ４３と遮断バネ４５の蓄勢を同時に行わなければならない。接圧バネ４３は投入時の接点に接触圧力を与えるためのバネであり、遮断バネ４５は遮断動作を行うためのバネである。
【００６７】
接圧バネ４３は絶縁ロッド６３内に収納されている。接圧バネ４３周辺の構造を図１４に示す。接圧バネ４３は、絶縁ロッド６３にモールドした接圧バネホルダ４３ａ内に収納してある。可動導体３６は接続部材４３ｂに固定し、接続部材４３ｂはピン４３ｃによって接圧バネホルダ４３ａと連結する。接続部材４３ｂにはピン４３ｃの外径よりやや大きめの穴が、接圧バネホルダ４３ａには楕円穴４３ｄが設けてある。投入動作において、固定接点３７と可動接点３８が接触すると、ピン４３ｃが楕円穴４３ｄ内を移動し始め（図中下向き）、投入動作が完了するまで接圧バネ４３を圧縮しつづける。一方、遮断バネ４５は、操作機構部４０の天板４６と接続部材９に固定された板４７とで挟持される。遮断バネ４５は、投入動作中、常に圧縮されつづける。
【００６８】
開閉装置２０の動作について説明する。コイル３を通電し、図７に示す磁界Ｂｃを発生させると、可動鉄心１は吸引力Ｆ０によって下向きに駆動され、それに伴って可動導体３６が上向きに移動し、接点が投入される。投入動作完了後にコイル３の電流を遮断しても、永久磁石１２の吸引力によってこの状態は保持される。遮断動作では、投入動作のときと逆向きの電流をコイル３に通電すると、図８に示したように永久磁石１２の磁界Ｂｍを打ち消して吸引力Ｆ０が低減するため、遮断バネ４５の力によって可動導体３６は下向きに駆動される。
【００６９】
次に、本実施例の効果について説明する。参考例１、２及び実施例１の電磁石１０のいずれかを開閉装置に適用することによって、投入状態の保持に使う永久磁石１２が減磁することなく、２０年の長期保証、１万回以上の多数回動作を満足できるようになる。すなわち、長寿命で信頼性の高い開閉装置を提供できる。
【００７０】
上記実施例２では、開閉装置を駆動するのに1個の電磁石を用いた例を示したが、容量の大きな、つまり開閉動作に大きな力が要求される遮断器に対しては、負荷の大きさに相応した力を出せるように、複数の電磁石を用いる。この場合、基準形となる寸法の電磁石を設定しておき、基準形の電磁石を複数組み合わせて所要の開閉操作力を出せるようにすればよい。
【００７１】
図15、図16に、それぞれ4個の電磁石を用いた遮断器の例を示す。図15、図16はいずれも、前記図13における操作機構部４０の天板４６、絶縁架台３１、制御回路５１、固定側フィーダ３９、可動側フィーダ６２などを取り除いた状態での平面図に相当し、シャフト４１への電磁石の取りつけ方法を示している。
【００７２】
図１５に示す例は、3相の電路の各相に対応する真空バルブ３０ａ，３０ｂ，３０ｃがシャフト４１に、それぞれレバー４２ａ，４２ｂ，４２ｃで結合され、同型、同仕様の電磁石１０ａ、１０ｂ、１０ｃ、１０ｄが、それぞれレバー４４ａ，４４ｂ，４４ｃ、４４ｄでシャフト４１に結合されている。つまり、4個の電磁石がそれぞれ個別にシャフト４１に駆動力を作用させる構成である。
【００７３】
図１６に示す例は、真空バルブ３０ａ，３０ｂ，３０ｃをシャフト４１に結合する方法は前記図15に示す例と同じであるが、電磁石をシャフト４１に結合する方法が前記図15に示す例と異なる。図16においては、シャフト４１の両端にレバー４４ａ，４４ｂが結合され、レバー４４ａ，４４ｂを連結する連結棒５２が、レバー４４ａ，４４ｂの各端部に枢着されている。同型、同仕様の電磁石１０ａ、１０ｂ、１０ｃ、１０ｄは、それぞれ前記連結棒５２に結合され、連結棒５２、レバー４４ａ、４４ｂを介してシャフト４１に駆動力を作用させる構成である。
【００７４】
いずれも、使用する複数の電磁石を、同型、同仕様の電磁石とすることによって、簡易な構成で複数の電磁石による開閉操作を実現することができる。
【００７５】
【発明の効果】
本発明の電磁石およびそれを用いた開閉装置の操作機構によれば、永久磁石に逆励磁をかけないので、小型で安価で信頼性が高い製品を提供できる。また永久磁石とそれに対向して進退する可動鉄心間の空隙を調整できるようにしたので、安価で信頼性が高い製品を提供できる。
【図面の簡単な説明】
【図１】本発明の参考例１である電磁石の断面図を示す。
【図２】本発明の参考例１である電磁石の吸引動作開始直後の状態を示す。
【図３】本発明の参考例１である電磁石の吸引動作完了直前の状態を示す。
【図４】本発明の参考例１である電磁石の吸引動作完了の状態を示す。
【図５】本発明の参考例１である電磁石の釈放動作中の状態を示す。
【図６】本発明の参考例２である電磁石の吸引動作開始直後の状態を示す。
【図７】本発明の参考例２である電磁石の吸引動作完了直前の状態を示す。
【図８】本発明の参考例２である電磁石の釈放動作中の状態を示す。
【図９】本発明の実施例１である電磁石の入状態を示す。
【図１０】本発明の実施例１である電磁石の切状態を示す。
【図１１】本発明の実施例１である電磁石の入動作中の状態を示す。
【図１２】本発明の実施例１である電磁石の切動作中の状態を示す。
【図１３】本発明の電磁石を適用した真空遮断器の構造を示す。
【図１４】本発明の真空遮断器における接圧バネ４３周辺部の構造を表す。
【図１５】本発明の電磁石を複数個用いる真空遮断器の、電磁石の結合方式の例を示す。
【図１６】本発明の電磁石を複数個用いる真空遮断器の、電磁石の結合方式の他の例を示す。
【符号の説明】
１可動鉄心
２固定鉄心
２ａ，２ｅ鋼管
２ｂ凸型鋼材
２ｃリング状の鋼板
２ｄ第２の角形平板
２ｆ第１の角形平板
２ｇ円筒
３コイル
４突出部
５プランジャ
６円盤状の鋼板
６ａ円筒平板
７接続部材
１０電磁石
１５，１５ａ管
１８第３の角形平板
２０真空遮断器
２１薄板
３０真空バルブ
４３接圧バネ
４５遮断バネ
Ｆ吸引力
ｇギャップ
Ｌギャップ
Ｏ磁界の経路
Ｗ負荷
Φ 磁界。[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to an electromagnet and a configuration of an operation mechanism of a switchgear using the electromagnet, and more particularly to an electromagnet that suppresses demagnetization of a permanent magnet and a highly reliable switchgear operation mechanism to which the electromagnet is applied.
[0002]
[Prior art]
  The operation mechanism of the switchgear includes an electric spring operation mechanism, a hydraulic type and a pneumatic type operation mechanism. Usually, these operation mechanisms have a relatively high production cost due to a large number of parts and a complicated link mechanism. One of the techniques for simplifying the link mechanism is an operation mechanism using an electromagnet. For example, in a vacuum contactor described in Japanese Patent Application Laid-Open No. 5-234475, an electromagnet is used for a closing operation, and energy is stored simultaneously with the closing. Release the contact spring to release the contact spring. In the operation mechanism described in JP 10-505940 A, a plunger that penetrates two coils for making and shutting off is provided, and both the making and shutting operations are performed by an electromagnet. In Japanese Patent Laid-Open No. 2000-249092, the closing state is maintained by using the attractive force of the permanent magnet, and the blocking operation is performed by the individually provided movable member driving springs by reverse excitation with the coil current. . In this case, there is an advantage that the coil may be a single coil regardless of whether the coil is turned on or off.
[0003]
[Problems to be solved by the invention]
  However, conventional electromagnets with permanent magnets have the following drawbacks. Permanent magnets include rare earth samarium-cobalt magnets, neodymium magnets, alnico magnets, and ferrite magnets. When a neodymium magnet having a high residual magnetic flux density and a relatively low cost is used, the electromagnet can be made small and inexpensive. However, the neodymium magnet has a large coercive force of 1000 kA / m and a magnetizing magnetic field of 2000 kA / m (corresponding to a magnetic flux density of 2.5 T) or more is required. Therefore, it is practically impossible to magnetize the permanent magnet with the coil of the incorporated electromagnet, and the magnet after magnetizing must be incorporated.
[0004]
  When an electromagnet is applied to an operation mechanism of a switchgear, it is necessary to satisfy a long-term operation guarantee of 20 years or more and a large number of operations of 10,000 times or more. Therefore, the factor that demagnetizes the permanent magnet must be eliminated as much as possible. In the electromagnet with a permanent magnet described in JP 2000-249092, a blocking operation is performed by applying a reverse magnetic field directly to the permanent magnet. By repeatedly applying reverse energy to the permanent magnet, there is a risk of demagnetization, that is, a reduction in life.
[0005]
  Furthermore, if a permanent magnet exists in the magnetic path, the magnetic resistance viewed from the coil increases. Since the permeability of the permanent magnet is about the same as that of air, there is a gap obtained by adding the thickness of the permanent magnet to the stroke length at the start of operation, and a larger ampere turn is required.
[0006]
  In addition, dimensional errors that occur in the manufacturing stage are unavoidable in the thickness of the permanent magnet and the iron core, and due to this dimensional error, the gap at the stroke end between the permanent magnet and the movable iron core that moves forward and backward is changed. . The throwing characteristics, blocking characteristics, and throwing state holding force (adsorption force) are changed by the gap. However, if the tolerance of the dimensional error, that is, the tolerance is strictly controlled in order to stabilize the characteristics, it becomes a bottleneck for manufacturing an inexpensive electromagnet.
[0007]
  The present invention has been devised as a means for solving the above-mentioned problems. The object of the present invention is to provide a long-life and high-performance without direct reverse excitation of the permanent magnet and no permanent magnet in the magnetic path created by the coil current. An object of the present invention is to provide an efficient electromagnet and an operation mechanism of a switchgear using the electromagnet. Another object of the present invention is to provide an electromagnet in which it is easy to adjust the distance between a permanent magnet and a movable iron core that moves forward and backward.
[0008]
[Means for Solving the Problems]
  That is, the present invention includes a coil 3, a movable iron core 1 that moves on the central axis of the coil 3, and a fixed iron core 2 provided on the upper surface, the lower surface, and the outer peripheral surface of the coil 3. A permanent magnet 12 is disposed in a space surrounded by the fixed iron core 2, and the movable iron core 1 is attracted to the fixed iron core 2 by a magnetic field generated by the permanent magnet 12. A first rectangular flat plate 2f having a circular opening concentric with the coil at the center, and a concentric surface placed on the upper surface of the first rectangular flat plate 2f and covering the outer peripheral surface of the coil The steel pipe 2e, and a second rectangular flat plate 2d placed on the upper end of the steel pipe 2e and provided on the upper surface side of the coil and having a circular opening concentric with the coil at the center, On the upper surface of the second rectangular flat plate A permanent magnet is disposed, and the movable iron core includes a cylindrical flat plate having a surface facing the upper surface of the second rectangular flat plate across the permanent magnet, and a plunger member having a cylindrical surface facing the inner peripheral surface of the coil A thin magnetic member is interposed between the cylindrical flat plate side end surface of the plunger member and the cylindrical flat plate.The distance g1 between the inner peripheral surface of the second rectangular flat plate and the cylindrical surface of the plunger member is smaller than the axial thickness t of the permanent magnet.The electromagnet 10.
[0009]
  In the electromagnet, a rod having a cylinder disposed concentrically with the steel pipe on the upper surface of the second rectangular flat plate and a third rectangular flat plate stacked on the upper surface of the cylinder, and having a rod provided with threaded portions at both ends. The first square flat plate, the second square flat plate, and the third square flat plate may be passed through and the screw portions at both ends of the rod may be tightened with nuts..
[0011]
  Electromagnet aboveThe coil 3 is provided with a power supply circuit capable of selectively passing a current in the forward direction and the reverse direction, and generates a magnetic field in the same direction as the magnetic field generated by the permanent magnet 12 when the current is passed in the forward direction. When the current is applied in the opposite direction, the permanent magnet cancels the magnetic field generated by 12 and releases it.Do.
[0012]
  The present invention also provides a coil, a movable iron core that moves on the central axis of the coil, fixed iron cores provided on both end surfaces and outer peripheral surfaces of the coil in the axial direction, and current in the forward and reverse directions of the coil. An electromagnet that moves the movable iron core toward the fixed iron core when the coil is energized in a forward direction, wherein the fixed iron core is one end surface in the axial direction of the coil. A fixed core upper member provided to cover the upper surface of the fixed core upper member, and a permanent magnet is disposed on an upper surface of the fixed core upper member, and the movable core is disposed on an upper surface of the upper member of the fixed core with the permanent magnet interposed therebetween. A cylindrical flat plate having opposing surfaces; and a plunger member having a cylindrical surface facing the inner peripheral surface of the coil; and the fixed iron core is provided on one end surface in the axial direction of the coil. A first rectangular flat plate having a circular opening concentric with the coil at the center, and a steel pipe disposed so that one end face in the axial direction is opposed to the first rectangular flat plate and covers the outer peripheral surface of the coil. And a second rectangular flat plate provided on the other axial end surface of the coil facing the other axial end surface of the steel pipe and having a circular opening concentric with the coil at the center, A thin magnetic member is interposed between the cylindrical flat plate end surface of the plunger member and the cylindrical flat plate.The gap g1 between the inner peripheral surface of the second rectangular flat plate and the cylindrical surface of the plunger member is smaller than the axial thickness t of the permanent magnet.It is characterized by that.
[0014]
  The permanent magnet may be selected from permanent magnets including rare earth samarium-cobalt magnets, neodymium magnets, alnico magnets, and ferrite magnets.
[0015]
  Further, the present invention includes the above-described electromagnet, a contact point that can be separated from and separated from the electromagnet, and a breaking spring that opens the contact point, and selectively allows forward and reverse currents to flow through the coil 3 of the electromagnet. A power supply circuit is provided, and when a current flows in the forward direction, the contact spring is turned on while accumulating the breaking spring, the applied state is maintained by the attractive force of the permanent magnet 12, and the coil 3 is reversed. It is an operating mechanism of the switchgear that cancels out the magnetic flux generated by the permanent magnet 12 when current is passed, and interrupts it with the force of the interrupting spring.
[0016]
  It is desirable to use a combination of a plurality of electromagnets used in the operation mechanism in accordance with the capacity of the switchgear.
[0017]
  That is, in the case of the electromagnet configured as described above, the magnetic field generated by passing a current in the reverse direction through the coil does not penetrate the permanent magnet during the cutting operation, so that the permanent magnet is not directly reverse-excited and the coil Since there is no permanent magnet in the magnetic path created by the current, there is no cause for demagnetizing the permanent magnet, and it is possible to use a neodymium-based permanent magnet, which can provide an electromagnet having a long life and excellent efficiency.
[0018]
  Further, the plunger memberCylindrical plate sideEnd face and saidCylindrical plateBy interposing a magnetic member between them, the thickness of the magnetic member is changed, or the magnetic member is made of a thin plate material, and the number of the thin plate materials is changed, so that the permanent magnet is moved forward and backward. The gap at the stroke end of the movable core can be easily adjusted. That is, the characteristics can be stabilized without tightening the tolerances of the parts, and an inexpensive and highly reliable electromagnet can be provided. Furthermore, by applying an operating mechanism of the switchgear to the electromagnet, it is possible to realize a switchgear that is small, inexpensive, and highly reliable.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
  Of the present inventionReference exampleWill be described with reference to FIGS.
[0020]
  (Reference example 1)
  Of the present inventionReference example 1Will be described with reference to FIGS.
[0021]
  FIG. 1 illustrates the present invention.Reference example 1It is sectional drawing of the electromagnet 10 which is. The electromagnet 10 has an axisymmetric structure, and a symbol for structural description is added to the right half of the figure, and the magnetic field B (chain line) generated by the current flowing through the permanent magnet 12 and the coil 3 is shown on the left half.
[0022]
  The movable iron core 1 is composed of a plunger 5 penetrating on the central axis of the coil 3 and a disk-shaped steel plate 6 fixed to the end thereof, and a load W is applied by a nonmagnetic connecting member 7 fixed to the end of the plunger 5. Connect to. The load W exerts a force to drive the movable iron core 1 upward while the electromagnet 10 is attracted. The fixed iron core 2 is composed of a steel pipe 2a, a convex steel material 2b, and a ring-shaped steel plate 2c, all of which are magnetic bodies. The convex steel material 2b and the ring-shaped steel plate 2c may be attached by screwing from both ends of the steel pipe 2a as shown, or may be fixed by welding. Further, the steel pipe 2a and the convex steel material 2b, or the steel pipe 2a and the ring-shaped steel plate 2c may be manufactured by cutting from a cylindrical material. Here, the steel material 2b has a convex shape, but it may of course be a simple flat plate. However, it is known that if the gap X between the end face of the plunger 5 and the fixed iron core 2 is provided near the center of the coil 3, the leakage magnetic flux is reduced, and it is better to use a convex steel material. Further, the convex steel material 2b may be manufactured as a single piece, or may be configured by connecting two steel plates. The coil 3 includes a bobbin 3a made of an insulator or a non-magnetic metal (aluminum, copper, etc.) and a winding 3b.
[0023]
  The ring-shaped steel plate 2c is screwed into the steel pipe 2a relatively deeply and is provided with a magnetic projection 4.Reference exampleThe electromagnet 10 has a structure in which the end surface of the plunger 5 and the convex steel material 2b, the disc-shaped steel plate 6 and the protruding portion 4 face each other in the same direction. The distance g between the side surface of the plunger 5 and the ring-shaped steel plate 2c was made shorter than the stroke length of the movable iron core. The reason for this will be described later. Further, the distance X between the end face of the plunger 5 and the convex steel material 2b is made shorter than the distance L between the disc-shaped steel plate 6 and the protruding portion 4, and the plunger 5 and the convex steel material 2b come into contact when the suction operation is completed. It becomes a state.
[0024]
  The ring-shaped permanent magnet 12 is disposed in a region surrounded by the plunger 5, the disk-shaped steel plate 6, the protrusion 4, and the ring-shaped steel plate 2c, and is fixed on the ring-shaped steel plate 2c. Reference numeral 13 denotes a holding metal fitting for the permanent magnet 12 made of a non-magnetic material such as SUS, for example, and the holding metal fitting 13 is fixed in a manner to be screwed into the steel pipe 2a. The holding metal fitting 13 provides a gap between the permanent magnet 12 and the protruding portion 4, in order to prevent the magnetic flux generated by the permanent magnet 12 from being short-circuited by the protruding portion 4.
[0025]
  Reference exampleThe operation of the electromagnet 10 will be described with reference to FIGS. 2 shows a state immediately after the start of the suction operation, FIG. 3 shows a state immediately before the completion of the suction operation, FIG. 4 shows a state after the completion of the suction operation, and FIG. 5 shows a state during the release operation.
[0026]
  When the coil 3 is energized by an external power supply circuit (not shown), the attractive force F0 acts on the end face of the plunger 5, and the movable iron core 1 starts to move downward. Here, since the distance g between the side surface of the plunger 5 and the ring-shaped steel plate 2c is set to be shorter than the stroke length of the movable iron core 1, the magnetic field Bc generated by the coil current passes through the path O1. Here, it is necessary to set the direction of the coil current and the polarity of the permanent magnet 12 in advance so that the direction of the magnetic field Bm and the direction of the magnetic field Bm generated by the permanent magnet 12 are in the direction of the arrow in FIG. Note that the directions of the magnetic field Bc and the magnetic field Bm may be simultaneously reversed.
[0027]
  When the movable iron core 1 is driven by the suction force F0, the state shown in FIG. 3 is reached. As the movable iron core 1 moves, the gap L between the disk-shaped steel plate 6 and the protruding portion 4 decreases and becomes shorter than the gap g between the plunger 5 and the ring-shaped steel plate 2c (g> L). Therefore, the magnetic field Bc due to the coil current starts to be diverted to the path O2, and most of it flows through the path O2 when the operation is completed. In other words, along with the movement of the movable iron core 1, in addition to the suction force F0 acting on the end surface of the plunger 5, the suction force F1 also acts between the disk-shaped steel plate 6 and the protruding portion 4. In the state immediately before completion of the attraction operation, the magnetic force B0 of the permanent magnet 12 passes through the path O3, so that the attraction force F0 is further increased.
[0028]
  When the coil 3 is turned off after the operation of the movable iron core 1 is completed, the attracted state is maintained by the attracting force of the permanent magnet 12. Even after the attraction operation is completed, there is a gap between the disk-shaped steel plate 6 and the protrusion 4, so that the magnetic field Bm generated by the permanent magnet 12 passes through the path O <b> 3. The suction state of the movable core 1 and the fixed core 2 is maintained by the suction force F0.
[0039]
  The release operation will be described with reference to FIG. The release operation is performed by applying a current in the direction opposite to that in the suction operation to the coil 3. The magnetic field Bc generated by the coil current flows through the path O2, and cancels the magnetic field Bm generated by the permanent magnet 12. The suction force F0 acting on the end surface of the plunger 5 is reduced, and the movable iron core 1 moves upward by the load force. However, since the attractive force Fr acts simultaneously between the disk-shaped steel plate 6 and the protruding portion 4 due to the magnetic field Bc, there is a possibility that when the excessive current is applied to the coil 3, the suction operation is performed again. It is necessary to provide a means for limiting the coil current by balance with the load force and immediately interrupting the coil current after the release operation is completed.
[0030]
  next,Reference exampleThe effect of will be described. In the conventional electromagnet with a permanent magnet, the permanent magnet 12 exists in the magnetic path created by the coil current, and thus the permanent magnet 12 is directly reverse-excited during the releasing operation. If reverse energy is continuously applied to the permanent magnet 12 by repeated operation, there is a risk of demagnetization.Reference exampleIn this electromagnet, the permanent magnet 12 is arranged in the gap surrounded by the movable iron core 1 and the fixed iron core 2, that is, arranged in the magnetically shielded region, so that the magnetic field Bc generated by the coil current does not directly act on the permanent magnet 12. . Even in the releasing operation, no reverse energy is applied to the permanent magnet 12. The risk of demagnetization is avoided, resulting in a long-life and highly reliable electromagnet.
[0031]
  Further, the permeability of the permanent magnet 12 is almost the same as that of air. If the permanent magnet 12 exists in the magnetic path created by the coil current, the magnetic resistance viewed from the coil increases. At the start of the operation, a gap corresponding to the stroke plus the thickness of the permanent magnet 12 exists, and the ampere turn necessary for the operation increases. In the electromagnet 10 of the present embodiment, since the permanent magnet does not exist in the magnetic path created by the coil current, the magnetic resistance is small and the efficiency is high.
[0032]
  (Reference example 2)
  Of the present inventionReference example 2Will be described with reference to FIGS.
[0033]
  FIG. 6 shows the present invention.Reference example 2It is sectional drawing of the electromagnet 10 which is. The movable iron core 1 is composed of a plunger 5 penetrating on the central axis of the coil 3 and a disk-shaped steel plate 6 fixed to the end thereof, and a load is applied by a nonmagnetic connecting member 7 fixed to the end of the plunger 5. Connecting. The fixed iron core 2 is composed of a steel pipe 2a, a convex steel material 2b, and a ring-shaped steel plate 2c, all of which are magnetic bodies. The convex steel material 2b and the ring-shaped steel plate 2c may be attached by screwing from both ends of the steel pipe 2a as shown, or may be fixed by welding. The convex steel material 2b may be manufactured as a single piece, or may be configured by connecting two steel plates. The coil 3 includes a bobbin 3a made of an insulator or a non-magnetic metal (aluminum, copper, etc.) and a winding 3b.
[0034]
  The ring-shaped permanent magnet 12 is fixed on the ring-shaped steel plate 2c. Reference numeral 15 denotes a pipe made of, for example, a nonmagnetic member such as SUS, and is fixed to the steel pipe 2a with the permanent magnet 12 sandwiched therebetween. Since a large force is not applied to the pipe 15, it may be fixed with a screw 16 or the like. The reason why the pipe 15 is made of a nonmagnetic member is to prevent the magnetic field of the permanent magnet 12 from being short-circuited by the pipe 15. Further, a lid 17 made of a nonmagnetic member is attached to the end of the pipe 15, and a rod 8 fixed to the movable iron core 1 passes therethrough. The lid 17, the convex steel material 2b, the connecting member 7 and the rod 8 prevent the axial displacement of the movable iron core 1.
[0035]
  The distance X between the end face of the plunger 5 and the convex steel material 2b is shorter than the distance L between the disk-shaped steel plate 6 and the permanent magnet 12, and the disk-shaped steel plate 6 collides and the permanent magnet 12 is destroyed. To avoid.
[0036]
  Reference exampleThe operation of the electromagnet 10 will be described with reference to FIGS. 6 to 9 show a cross section of the electromagnet 10, and a symbol for explaining the structure is added to the right half, and a magnetic field is added to the left half.
[0037]
  FIG. 6 shows a state immediately after the start of the suction operation. The distance X between the end surface of the plunger 5 and the convex steel material 2b and the distance L between the disk-shaped steel plate 6 and the permanent magnet 12 are both longer than the distance g between the permanent magnet 12 and the plunger 5, and the magnetic field Bm produced by the permanent magnet 12 is As shown in FIG. 6, it extends only to the periphery of the permanent magnet 12. Therefore, the driving force acting on the movable iron core 1 is very weak. When the coil 3 is energized from an external power supply circuit (not shown), the attractive force F0 acts on the end face of the plunger 5 by the magnetic field Bc caused by the coil current, and the movable iron core 1 starts to move downward. Here, since the distance g between the side surface of the plunger 5 and the ring-shaped steel plate 2c is set to be shorter than the stroke length of the movable iron core 1, the magnetic flux Bc generated by the coil current passes through the path O4. The direction of the coil current and the polarity direction of the permanent magnet 12 must be set in advance so that the direction of the magnetic field Bc caused by the coil current and the direction of the magnetic field Bm of the permanent magnet 12 are in the direction of the arrow shown in FIG. Note that the directions of the magnetic field Bc and the magnetic field Bm may be simultaneously reversed.
[0038]
  When the movable iron core 1 is driven by the suction force F0, the state shown in FIG. 7 is eventually reached. As the movable core 1 moves, the gap L between the disk-shaped steel plate 6 and the permanent magnet 12 decreases and becomes shorter than the gap g between the plunger 5 and the ring-shaped steel plate 2c (g> L). The magnetic field Bm of the magnet 12 passes through the path O5. That is, as the movement of the movable iron core 1 proceeds, the attractive force F1 acts between the disk-shaped steel plate 6 and the permanent magnet 12 as well as the attractive force F0 acting on the end face of the plunger 5. Further, since the magnetic field Bm of the permanent magnet 12 passes through the opposing surface of the plunger 5 and the convex steel material 2b, the attractive force F0 is further increased.
[0039]
  When the coil 3 is excited after the operation of the movable core 1 is completed, the attractive force F0 and the attractive force F1 are acted on by the magnetic flux Bm of the permanent magnet 12, and this state is maintained.
[0040]
  On the other hand, as shown in FIG. 8, the release operation is performed by supplying a current in the direction opposite to that in the suction operation to the coil 3. The magnetic field Bc generated by the coil current flows through the path O6 and cancels the magnetic field Bm generated by the permanent magnet 12. The suction force F0 is reduced, and the movable iron core 1 moves upward by the load force.
[0041]
  Reference exampleThe effect of will be described.Reference example 1As in the case of the electromagnet, the magnetic field Bc generated by the coil current does not directly act on the permanent magnet 12 and does not give reverse energy during the release operation. Therefore, the danger of permanent magnet demagnetization is avoided, resulting in a long-life and highly reliable electromagnet. Further, the permeability of the permanent magnet 12 is almost the same as that of air. If the permanent magnet 12 exists in the magnetic path created by the coil current, the magnetic resistance viewed from the coil increases. At the start of the operation, a gap corresponding to the stroke plus the thickness of the permanent magnet 12 exists, and the required ampere turn increases. In the electromagnet 10 of the present embodiment, since the permanent magnet does not exist in the magnetic path created by the coil current, the magnetic resistance is small and the efficiency is high.
[0042]
  further,Reference exampleThe electromagnet has the following effects. In release action,Reference example 1In this electromagnet, an attractive force F1 acts between the disk-shaped steel plate 6 and the magnetic projection 4 due to the magnetic field Bm generated by the coil current. It was. Therefore, it is necessary to provide means for limiting the coil current by balance with the load force and immediately interrupting the coil current after the release operation is completed. But,Reference exampleIn the electromagnet, there is no portion that generates an attractive force by the magnetic field Bc by the coil current, and the attractive operation is not performed again. Therefore, it is not necessary to limit the coil current by balance with the load force and to provide means for interrupting the coil current immediately after the release operation is completed.
[0043]
  (Example 1)
  Of the present inventionExample 1Will be described with reference to FIG. 9 (on state) and FIG. 10 (off state). 9 and 10 are cross-sectional views of an electromagnet 10 according to an embodiment of the present invention. FIG. 9 shows the electromagnet when the switchgear is turned on when coupled to the switchgear, and FIG. The electromagnet when the switchgear is turned off when coupled is shown. In the following description, both the on state and the off state refer to the state of the electromagnet when the electromagnet is coupled to the switchgear and the switchgear is in the on or off state.
[0044]
  The coil 3 includes a bobbin 3a made of an insulator or a nonmagnetic metal (aluminum, copper, etc.) and a winding 3b.
[0045]
  The illustrated electromagnet 10 is a fixed body made of a coil 3, a movable iron core made of a magnetic material that moves on the central axis of the coil 3, and a magnetic material provided so as to cover both axial end faces and the outer peripheral surface of the coil 3. An iron core and a power source (not shown) capable of flowing a current in the forward direction and the reverse direction through the coil 3 are configured. When the coil 3 is energized in the forward direction, the movable iron core is moved in a direction toward the fixed iron core, that is, from right to left in the figure. In the following description, for the sake of convenience, the direction is shown with the right side as the upper side and the left side as the lower side in FIG.
[0046]
  The fixed iron core is a fixed iron core upper member provided so as to cover one end face in the axial direction of the coil 3 and having a circular opening concentric with the coil 3 at the center.Second square flat plate2d and a fixed core lower member provided so as to cover the other end face in the axial direction of the coil and having a circular opening concentric with the coil 3 at the center.1st square flat plate2f and the aboveSecond square flat plate2d and1st square flat plateA steel pipe 2e sandwiched between 2f and covering the outer peripheral surface of the coil 3,1st square flat plateThe upper surface of 2f includes a cylinder 2g arranged concentrically with the steel pipe 2e.Second square flat plate2d,1st square flat plate2f, the steel pipe 2e, and the cylinder 2g are all magnetic materials,1st square flat plateThe 2f and the cylinder 2g are fixed with screws or the like, or are integrally welded. Of course, it may be cut out from one material.
[0047]
  SaidSecond square flat plateA disk-like permanent magnet 12 having an opening at the center is attracted and arranged on the upper surface of 2d, and is fixed by an adhesive. The permanent magnet 12 may be any material of neodymium, samarium, alnico, neodymium bond, and ferrite. In addition, the illustrated permanent magnet 12 is a single annular magnet, but does not necessarily have a continuous annular shape.Second square flat plateYou may arrange | position on the upper surface of 2d. However, also in this case, it is necessary that the area of the surface facing the cylindrical flat plate 6a described later is an area that can exhibit the required adsorption force.
[0048]
  The movable iron core isSecond square flat plateSaid opening of 2d,1st square flat plateA non-magnetic rod 19 that passes through the centers of the opening 2f, the steel pipe 2e, and the cylinder 2g, a plunger 5 that is a columnar magnetic body fitted and fixed to the rod 19, and an upper side of the plunger 5 And a cylindrical flat plate 6a, which is a magnetic body, which is disposed through a thin plate 21 which is a magnetic member and is fixed to the rod 19. The lower surface of the cylindrical flat plate 6 a faces the upper surface of the rectangular flat plate 2 d across the permanent magnet 12, and the outer peripheral surface of the plunger 5 faces the inner peripheral surface of the coil 3. In other words, the outer diameter of the plunger 5 is smaller than any of the inner diameter of the coil 3, the diameter of the central opening of the permanent magnet 12, and the diameter of the central opening of the rectangular flat plate 2d, and moves inside thereof in the axial direction. Although the outer diameter of the cylindrical flat plate 6 a is larger than the diameter of the central opening of the permanent magnet 12, the cylindrical flat plate 6 a cannot pass through the central opening of the permanent magnet 12. The plunger 5 and the cylindrical flat plate 6a are fixed to the rod 19 by screwing or a stopper.
[0049]
  A central opening of the permanent magnet 12;Second square flat plateThe central opening of 2d is concentric and of the same diameter, and the axial thickness t of the permanent magnet 12 isSecond square flat plateThe distance g1 between the inner peripheral surface of the center opening 2d and the outer peripheral surface of the plunger 5 is set larger.
[0050]
  The outer diameter of the cylinder 2g is smaller than the inner diameter of the coil 3, and is the same as the outer diameter of the plunger 5. Further, the inner diameter of the cylinder 2g is set such that the rod 19 can pass freely. That is, the lower surface of the plunger 5 faces the upper surface of the cylinder 2g, and when the movable iron core moves to the left in the axial direction, the limit of the movement is determined by the point where the lower surface of the plunger 5 and the upper surface of the cylinder 2g abut. .
[0051]
  On the upper side of the permanent magnet 12, a tube 15 a made of a non-magnetic material (stainless steel is used in this embodiment) is disposed concentrically with the coil 3, and the tube 15 a is sandwiched between the permanent magnet 12 and the permanent magnet 12.Third square flat plate18 is arranged.Third square flat plate18 may be magnetic or non-magnetic.1st square flat plate2f,Second square flat plate2d,Third square flat plateThe four corners of 18 or two corners on the diagonal line are perforated so that rods 14, which are non-magnetic materials with threads cut at both ends, pass through, and the ends of the rod 14 are fixed by tightening the nuts with nuts. It is.
[0052]
  Third square flat plate18,1st square flat plateIn 2f, a hole through which the rod 19 passes is formed concentrically with the coil 3, and a bearing or a dry bearing is provided in the hole portion to reduce friction when the rod 19 slides, thereby realizing maintenance-saving. ing.
[0053]
  The on state of FIG. 9 is held by the attractive force of the permanent magnet 12 (generated by the magnetic flux φ1). That is, the engaged state is the attractive force of the permanent magnet 12, and the state where the gap g3 between the lower surface of the plunger 5 and the upper surface of the cylinder 2g is 0, that is, the state where the lower surface of the plunger 5 is in contact with the upper surface of the cylinder 2g is maintained. Is done. The lower surface of the plunger 5 may not be in direct contact with the upper surface of the cylinder 2g, but a thin nonmagnetic material may be sandwiched therebetween.
[0054]
  When assembling the electromagnet, a plurality of thin plates 21 having the same thickness are prepared, and the number of the thin plates 21 sandwiched between the plunger 5 and the cylindrical flat plate 6a is changed, whereby the permanent magnet 12 and the cylindrical flat plate 6a in the state shown in FIG. A gap g2 having a desired size is formed between the two. The reason for creating the gap g2 is that when the cylindrical flat plate 6a directly collides with the permanent magnet 12 during the on-operation, the permanent magnet 12 is demagnetized and the life of the permanent magnet 12 is shortened.
[0055]
  Further, by changing the number of the thin plates 21 so that the gap g2 in the on state is as close to 0 as possible, the magnetic resistance can be reduced and the attractive force can be increased. As a result, the thickness of the permanent magnet is reduced, orSecond square flat plateEven if the volume of the permanent magnet 12 is reduced by reducing the surface area attracted to 2d, the conventional attractive force can be secured. Therefore, the cost of the permanent magnet that greatly depends on the volume is reduced, and a small and inexpensive electromagnet can be obtained. Further, by changing the number of the thin plates 21, the value of the gap g2 in the on state can be brought close to a desired constant value, so that the attraction force and the on / off operation characteristics of the permanent magnet in the on state can be stabilized. And the reliability of the electromagnet can be improved.
[0056]
  Instead of using multiple thin plates of the same thickness to adjust the value of the gap, prepare plates of various thicknesses with different thicknesses, one of which has an appropriate thickness Alternatively, the gap value may be adjusted by combining different thicknesses.
[0057]
  Next, the on / off operation will be described with reference to FIG. 11 (at the time of on / off operation) and FIG.
[0058]
  During the turning-on operation shown in FIG. 11, a current is supplied from a power source (not shown) to the coil 3 so as to generate a magnetic field in the same direction as the magnetic field generated by the permanent magnet 12 (forward current). The magnetic fluxes φ2 and φ1 shown in FIG. 11 are generated by the coil current and the permanent magnet 12, respectively, and an attractive force for moving the cylindrical flat plate 6a to the left in the figure, that is, a force for attracting the movable iron core to the fixed iron core is generated. This attractive force is generated both in the gap between the plunger 5 and the cylinder 2g and in the gap between the cylindrical flat plate 6a and the permanent magnet 12. The force generated in the gap between the cylindrical flat plate 6a and the permanent magnet 12 is F1, and the force generated in the gap between the plunger 5 and the cylinder 2g is F2. F2 at the time of on-operation is a force generated by the magnetic flux obtained by combining the magnetic flux φ2 and the magnetic flux φ1.
[0059]
  At the time of the cutting operation shown in FIG. 12, a current in the direction opposite to that at the time of the on operation is supplied from the power source (not shown) to the coil 3. When maintaining the ON state, the sum of the force F1 generated in the gap between the cylindrical flat plate 6a and the permanent magnet 12 by the magnetic flux φ1 formed by the permanent magnet and the force F2a generated in the gap between the plunger 5 and the cylinder 2g by the magnetic flux φ1. However, it is larger than the force F0 applied to the rod 19 in the right direction in the figure by a not-shown shut-off spring. That is, the force of the permanent magnet 12 overcomes the force of the cutoff spring, and the on state is maintained. In this state, when a current in the reverse direction flows through the coil 3, a magnetic flux φ5 opposite to the magnetic flux φ1 is formed by this current, and the magnetic flux φ1 of the permanent magnet 12 is weakened by the magnetic flux φ5. This weakened magnetic flux (or a magnetic flux in the direction opposite to the magnetic flux φ1) generates a force F2b in the gap between the plunger 5 and the cylinder 2g. Since F2a> F2b, the leftward force acting on the movable iron core is reduced, and F0> (F1 + F2b) is established, and the cutting operation is started.
[0060]
  At this time, the thickness t of the permanent magnet 12 isSecond square flat plateSince the distance g1 between the inner peripheral surface of the central opening 2d and the outer peripheral surface of the plunger 5 is larger, the magnetic flux φ5 formed by the reverse current does not pass through the permanent magnet 12 as shown in FIG. . This is because the magnetic permeability φ5 caused by the reverse current has a small magnetic resistance and the magnetic path shown in FIG. If the permanent magnet is continuously subjected to reverse excitation, it may be demagnetized. However, in the electromagnet of this embodiment, the permanent magnet is not subjected to reverse excitation. A highly reliable electromagnet can be obtained.
[0061]
  (Example 2)
  Of the present inventionExample 2Will be described with reference to FIGS. 13 and 14. FIG.
[0062]
  This exampleReference Examples 1-2, Example 1The described electromagnet 10 is applied to an operation mechanism of a switchgear.FIG.These are sectional side views of the three-phase vacuum circuit breaker 20 to which the electromagnet 10 described in Reference Example 2 is applied. Here, a vacuum circuit breaker will be described as an example, but the electromagnet 10 of the present invention can be applied to other switchgear such as a gas circuit breaker. Moreover, although the example which applied the electromagnet 10 of the reference example 2 is described, the electromagnet of the reference example 1 or Example 1 is applicable similarly.
[0063]
  The vacuum circuit breaker 20 includes a vacuum valve 30, an operation mechanism unit 40, an insulating mount 31, and an operation space 50 that houses the control circuit 51 and the electromagnet 10. The vacuum valves 30 are installed in a state where three phases are arranged in the depth direction of the drawing. The three vacuum valves 30 are connected by a shaft 41 in the operation mechanism unit 40 and are driven by a single electromagnet 10.
[0064]
  The vacuum valve 30 is kept in a vacuum state by a vacuum container composed of upper and lower end plates 32 and an insulating cylinder 33. A fixed contact 37 and a movable contact 38 are disposed in the vacuum valve 30 and are turned on and off by contact and separation thereof. The fixed contact 37 is fixed to the fixed conductor 35 and is electrically connected to the fixed feeder 39. On the other hand, the movable contact 38 is fixed to the movable conductor 36 and connected to the movable feeder 62 via the flexible conductor 61. The bellows 34 has both ends connected to the movable conductor 36 and the end plate 32. The fixed contact 37 and the movable contact 38 can be brought into and out of contact with each other while the vacuum state is maintained by the bellows 34.
[0065]
  Both the vacuum valve 30 and the electromagnet 10 are connected to the shaft 41, and the driving force generated by the electromagnet 10 is applied to the movable conductor 36. The movable conductor 36 is electrically insulated from the operating mechanism by an insulating rod 63 and is connected to a lever 42 fixed to the shaft 41. The movable iron core 1 of the electromagnet 10 is coupled to the lever 44 by the connecting member 9.
[0066]
  In the closing operation, the contact pressure spring 43 and the blocking spring 45 must be stored simultaneously. The contact pressure spring 43 is a spring for applying contact pressure to the contact at the time of closing, and the cutoff spring 45 is a spring for performing a cutoff operation.
[0067]
  The contact pressure spring 43 is accommodated in the insulating rod 63. The structure around the contact pressure spring 43 is shown in FIG. The contact pressure spring 43 is accommodated in a contact pressure spring holder 43 a molded on the insulating rod 63. The movable conductor 36 is fixed to the connection member 43b, and the connection member 43b is connected to the contact pressure spring holder 43a by a pin 43c. The connecting member 43b is provided with a hole slightly larger than the outer diameter of the pin 43c, and the contact pressure spring holder 43a is provided with an elliptical hole 43d. In the closing operation, when the fixed contact 37 and the movable contact 38 come into contact with each other, the pin 43c starts to move in the elliptical hole 43d (downward in the figure), and continues to compress the contact pressure spring 43 until the closing operation is completed. On the other hand, the blocking spring 45 is sandwiched between the top plate 46 of the operation mechanism unit 40 and the plate 47 fixed to the connecting member 9. The shut-off spring 45 is always compressed during the closing operation.
[0068]
  The operation of the opening / closing device 20 will be described. When the coil 3 is energized and the magnetic field Bc shown in FIG. 7 is generated, the movable iron core 1 is driven downward by the attractive force F0, and accordingly, the movable conductor 36 is moved upward and the contact is turned on. Even if the current of the coil 3 is interrupted after the closing operation is completed, this state is maintained by the attractive force of the permanent magnet 12. In the interruption operation, when a current in the opposite direction to that in the closing operation is applied to the coil 3, the magnetic force B0 of the permanent magnet 12 is canceled and the attractive force F0 is reduced as shown in FIG. The movable conductor 36 is driven downward.
[0069]
  Next, the effect of the present embodiment will be described.One of the electromagnets 10 of Reference Examples 1 and 2 and Example 1By applying the switchgear to the switchgear, the permanent magnet 12 used for maintaining the closed state can be satisfied with a long-term guarantee of 20 years and a large number of operations of 10,000 times or more. That is, it is possible to provide a highly reliable switchgear with a long life.
[0070]
  the aboveExample 2Shows an example of using one electromagnet to drive the switchgear, but for a circuit breaker with a large capacity, that is, a large force required for the switching operation, it corresponds to the size of the load. Use multiple electromagnets to generate force. In this case, an electromagnet having a reference size may be set, and a plurality of reference electromagnets may be combined so that a required opening / closing operation force can be generated.
[0071]
  15 and 16 show examples of circuit breakers each using four electromagnets. 15 and 16 correspond to plan views in a state where the top plate 46, the insulating base 31, the control circuit 51, the fixed feeder 39, the movable feeder 62, etc. of the operation mechanism section 40 in FIG. 13 are removed. The method of attaching the electromagnet to the shaft 41 is shown.
[0072]
  In the example shown in FIG. 15, vacuum valves 30a, 30b, and 30c corresponding to respective phases of a three-phase electric circuit are coupled to a shaft 41 by levers 42a, 42b, and 42c, respectively. 10c and 10d are coupled to the shaft 41 by levers 44a, 44b, 44c and 44d, respectively. That is, each of the four electromagnets individually applies a driving force to the shaft 41.
[0073]
  In the example shown in FIG. 16, the method of coupling the vacuum valves 30a, 30b, 30c to the shaft 41 is the same as the example shown in FIG. 15, but the method of coupling the electromagnet to the shaft 41 is the same as the example shown in FIG. Different. In FIG. 16, levers 44a and 44b are coupled to both ends of the shaft 41, and a connecting rod 52 for connecting the levers 44a and 44b is pivotally attached to each end of the levers 44a and 44b. The electromagnets 10a, 10b, 10c, and 10d of the same type and the same specification are coupled to the connecting rod 52, and drive force is applied to the shaft 41 via the connecting rod 52 and levers 44a and 44b.
[0074]
  In any case, by using a plurality of electromagnets of the same type and the same specifications, an opening / closing operation with a plurality of electromagnets can be realized with a simple configuration.
[0075]
【The invention's effect】
  According to the electromagnet of the present invention and the operation mechanism of the switchgear using the electromagnet, reverse excitation is not applied to the permanent magnet, so that a small, inexpensive, and highly reliable product can be provided. In addition, since the gap between the permanent magnet and the movable iron core that moves forward and backward can be adjusted, an inexpensive and highly reliable product can be provided.
[Brief description of the drawings]
FIG. 1 of the present inventionReference example 1Sectional drawing of the electromagnet which is is shown.
FIG. 2 of the present inventionReference example 1The state immediately after the attraction | suction operation | movement start of the electromagnet which is is shown.
FIG. 3 of the present inventionReference example 1The state just before completion of attraction | suction operation | movement of the electromagnet which is is shown.
FIG. 4 of the present inventionReference example 1This shows the state of completion of the attraction operation of the electromagnet.
FIG. 5 shows the present invention.Reference example 1The state during the release operation of the electromagnet is shown.
FIG. 6 of the present inventionReference example 2The state immediately after the attraction | suction operation | movement start of the electromagnet which is is shown.
[Fig. 7] of the present invention.Reference example 2The state just before completion of attraction | suction operation | movement of the electromagnet which is is shown.
[Fig. 8] of the present inventionReference example 2The state during the release operation of the electromagnet is shown.
FIG. 9 shows the present invention.Example 1It shows the on state of the electromagnet.
FIG. 10 shows the present invention.Example 1The electromagnet cut-off state is shown.
FIG. 11 shows the present invention.Example 1The state during the turning-on operation of the electromagnet is shown.
FIG. 12 shows the present invention.Example 1The state in the cutting | disconnection operation | movement of the electromagnet which is is shown.
FIG. 13 shows the structure of a vacuum circuit breaker to which the electromagnet of the present invention is applied.
FIG. 14 shows the structure around the contact pressure spring 43 in the vacuum circuit breaker of the present invention.
FIG. 15 shows an example of an electromagnet coupling method of a vacuum circuit breaker using a plurality of electromagnets of the present invention.
FIG. 16 shows another example of the electromagnet coupling method of the vacuum circuit breaker using a plurality of electromagnets of the present invention.
[Explanation of symbols]
  1 Movable iron core
  2 Fixed iron core
  2a, 2e steel pipe
  2b Convex steel
  2c Ring-shaped steel plate
  2d second square plate
  2f First square flat plate
  2g cylinder
  3 coils
  4 Protrusion
  5 Plunger
  6 Disc-shaped steel plate
  6a Cylindrical flat plate
  7 Connecting members
  10 Electromagnet
  15,15a tube
  18 Third square flat plate
  20 Vacuum circuit breaker
  21 Thin plate
  30 Vacuum valve
  43 Contact pressure spring
  45 Blocking spring
  F suction power
  g Gap
  L gap
  O Magnetic path
  W load
  Φ magnetic field.

Claims

A permanent magnet is formed in a gap surrounded by the movable core and the fixed core, the coil, a movable core moving on the central axis of the coil, and a fixed core provided on the upper surface, the lower surface, and the outer peripheral surface of the coil. An electromagnet that attracts the movable iron core to the fixed iron core by a magnetic field generated by the permanent magnet, the fixed iron core being provided on the lower surface side of the coil and having a circular shape concentric with the coil A first rectangular flat plate having an opening, a concentric steel pipe placed on the upper surface of the first rectangular flat plate to cover the outer peripheral surface of the coil, and an upper face side of the coil placed on the upper end of the steel pipe And a second rectangular flat plate having a circular opening concentric with the coil at the center, the permanent magnet is disposed on the upper surface of the second rectangular flat plate, and the movable iron core is , With the permanent magnet in between A cylindrical flat plate having a surface facing the upper surface of the rectangular flat plate, and a plunger member having a cylindrical surface facing the inner peripheral surface of the coil, and the end surface of the plunger member on the cylindrical flat plate side and the cylindrical flat plate And a gap g1 between the inner peripheral surface of the second rectangular flat plate and the cylindrical surface of the plunger member is smaller than the axial thickness t of the permanent magnet. An electromagnet characterized by that.

2. The electromagnet according to claim 1, further comprising: a cylinder disposed concentrically with the steel pipe on an upper surface of the second rectangular flat plate; and a third rectangular flat plate stacked on the upper surface of the cylinder, and screw portions at both ends. An electromagnet comprising a rod provided through the first rectangular flat plate, the second rectangular flat plate, and the third rectangular flat plate, and screwed at both ends of the rod with nuts.

A coil, a movable iron core that moves on the central axis of the coil, fixed iron cores provided on both axial end faces and an outer peripheral surface of the coil, and a power source capable of causing a current to flow in the forward and reverse directions of the coil In the electromagnet that moves the movable iron core toward the fixed iron core when energized in the forward direction to the coil, the fixed iron core is provided on one end face in the axial direction of the coil, A first rectangular flat plate having a circular opening concentric with the coil, a steel pipe disposed so that one end surface in the axial direction is opposed to the first rectangular flat plate and covering an outer peripheral surface of the coil, and A second rectangular flat plate provided on the other axial end surface of the coil facing the other axial end surface and having a circular opening concentric with the coil at the center. The upper surface of the permanent magnet The movable iron core is disposed and includes a cylindrical flat plate having a surface facing the upper surface of the second rectangular flat plate with the permanent magnet interposed therebetween, and a plunger member having a cylindrical surface facing the inner peripheral surface of the coil. And a thin magnetic member is interposed between the cylindrical flat plate side end surface of the plunger member and the cylindrical flat plate, and the distance between the inner peripheral surface of the second square flat plate and the cylindrical surface of the plunger member An electromagnet characterized in that g1 is smaller than an axial thickness t of the permanent magnet .

The electromagnet according to any one of claims 1 to 3, a contactable and separable contact, and a cutoff spring for opening the contact, wherein the coil of the electromagnet has a forward direction and a reverse direction. A power supply circuit that can selectively flow a current in the direction is provided, and when a current flows in the forward direction, the contact is turned on while accumulating the breaking spring, and the charged state is maintained by the attractive force of the permanent magnet. An operation mechanism for an opening / closing device , wherein when a current in a reverse direction is passed through the coil, the magnetic flux generated by the permanent magnet is canceled and the coil is interrupted by the force of the interrupting spring.

The operating mechanism of the switchgear according to claim 4, wherein a plurality of the same electromagnets are used in combination.