JP2004076141A - Vacuum valve used for vacuum interrupter, and manufacturing method of electric contact - Google Patents
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【０００１】
【発明の属する技術分野】
本発明は、電気接点部材、それを用いた真空バルブ、それらを用いた真空遮断器、それらの製造方法に関する。
【０００２】
【従来の技術】
真空遮断器に設置される真空バルブ内の電極構造は、一対の固定側電極及び可動側電極を有して構成されている。固定側及び可動側電極の構造は、電気接点と該電気接点に連なる電極棒とを有し、電気接点の裏面にはしばしばステンレス等の板が補強板として設けられる。
【０００３】
電気接点は高電圧，大電流を開閉遮断するために直接アークにさらされる。電気接点に要求される特性は、遮断容量が大きいこと、耐電圧値が高いこと、耐溶着性に優れることなどが挙げられる。特に年々、配電の高電圧化が進む中、真空遮断器あるいは真空開閉器等においても、大電流遮断と高耐電圧特性及び耐溶着性能の両立が求められている。
【０００４】
大電流，高電圧遮断用電気接点部材としては、Ｃｒ−Ｃｕの複合金属材料が多く用いられる。この電気接点部材の製造方法としては、各成分の金属粉末あるいはこれらの混合粉を所定の組成で、例えば円板等の単純形状に成形及び焼結するいわゆる粉末冶金法と、成形したスケルトンにＣｕあるいはその合金溶湯をしみこませ、機械加工して所定形状とするいわゆる溶浸法とがあり、これら製造方法については特開平９−２１３１５３号公報，特願２０００−１８８０４５号公報等に記載されている。
【０００５】
【発明が解決しようとする課題】
しかしながら、上記公報に記載されている電気接点部材であっても、これらの特性を全て満足することにおいては未だ解決課題を有しており、一般には用途に応じて特に重要な特性を重視し、他の特性はある程度犠牲にした材料が用いられる。例えばＣｒ−Ｃｕの複合金属材料において、遮断容量を大きくするためには導電率が大きいことが必要であるがＣｕ量を多くした組成とすることで対処できる。しかしながら一方で耐電圧性能を上げる成分であるＣｒ量が減ってしまうため耐電圧値，耐溶着性が低下してしまう。反対にＣｒ量を多くすることで耐電圧値と耐溶着性を向上させることができるが、Ｃｒ量を多くするとＣｕ量が減ってしまうため導電率は低下し、遮断性能が不十分となり、大電流遮断性能と高耐電圧特性及び耐溶着性能を両立するのは極めて困難であった。
【０００６】
以上、本発明の目的は安定した遮断性能，耐電圧特性及び耐溶着性能を兼ね備えた電気接点部材、それを用いた真空バルブ、それらを用いた真空遮断器を提供することにある。
【０００７】
【課題を解決するための手段】
上記目的を達成するために、電極接点部材において、１５〜４０重量％のＣｒと、６０〜８５重量％のＣｕと、不可避の不純物とを有し、Ｃｕ中のＣｒ固溶量が５００ｐｐｍ 以下であることを特徴とする。これにより耐電圧特性及び耐溶着性能を向上させるために耐火性金属成分の含有量を多くしても、導電性を向上させることができ、遮断性能を確保することができる。耐火性金属であるＣｒ量を多くしても導電率の改善が得られるので、遮断性能，耐電圧性能及び耐溶着性能を併せ持つ真空バルブを作製することができる。
【０００８】
【発明の実施の形態】
本発明者らは、粉末冶金法あるいは溶浸法等により得られた電気接点部材に高真空雰囲気での熱処理を施すことで、製造過程においてマトリックス中に固溶した耐火性金属成分あるいは他の不純物が晶出し、Ｃｕマトリックスの導電性が向上し、遮断性能が向上することを見出した。これにより、耐電圧特性及び耐溶着性能を向上させるために耐火性金属成分の含有量を多くしても、導電性を向上させることができ、遮断性能を確保することができる。また、溶浸法あるいは焼結法で作製した電気接点部材を用いた真空バルブに対して、大気中，不活性ガス流中または真空中で熱処理を施した場合にも、同様の効果が得られることを見出した。従って耐火性金属であるＣｒ量を多くしても導電率の改善が得られるので、遮断性能，耐電圧性能及び耐溶着性能を併せ持つ真空バルブを作製することができる。
【０００９】
具体的な態様としては、電気接点部材を１５〜４０重量％のＣｒと６０〜８５重量％のＣｕ及び不可避の不純物とからなり、Ｃｕ中におけるＣｒ固溶量が５００ｐｐｍ 以下であるものとする。または１５〜４０重量％のＣｒと６０〜８５重量％のＣｕ及び不可避の不純物とからなり、比抵抗ｙ（μΩ・ｃｍ）がＣｒの重量分率ｘに基づいて以下の（１）式によって求められる値以下であるものとする。
【００１０】
ｙ＝２５．４ｘ４−６２．１ｘ３＋３２．６ｘ２＋６．９ｘ＋１．６９８ …（１）
（但し、０．１５≦ｘ≦０．４）
また、不純物として酸素を５０〜２０００ｐｐｍ 、Ａｌを５０〜３０００ｐｐｍ 、Ｓｉを４００〜２５００ｐｐｍ 含むＣｒを用いる。これら不純物成分は遮断時における優れた消弧作用を得るために有用であり、これにより遮断性能が安定する。若しくは電気接点部材を４００〜５０００ｐｐｍ の酸素を含有することが有用である。なおＡｌ，Ｓｉはそれぞれ酸化物として存在してもよい。高融点で硬質の微細なＡｌ，Ｓｉ酸化物が均一に分散していることにより優れた耐溶着性，耐電圧特性が得られるからである。但し、酸素量が４００ｐｐｍ より少ないとアークの移動速度が低下し、電極上の特定個所に停滞しやすくなり、遮断不能を引き起こす可能性が大きくなり、また５０００ｐｐｍ より多いと電流遮断時のガスの放出量が多くなり、ガスを介したアーク持続により遮断不能を引き起こす。
【００１１】
また真空バルブを、真空容器内に固定側電極と可動側電極とを備えたもので、この固定側電極及び可動側電極には、上記に記載した電気接点部材を用いたものとする。
【００１２】
さらに、真空遮断器を、真空容器内に固定側電極と可動側電極とを備えた真空バルブと、この真空バルブ内の固定側電極と可動側電極との各々に真空バルブ外に接続された絶縁ロッドを介して前記の可動側電極を駆動する開閉手段とを備えたものとし、この真空遮断器における真空バルブは、上記に記載の真空バルブからなるものとする。
【００１３】
またこの電気接点部材の製造方法として、Ｃｒ粉末とＣｕ粉末からなる成形体上にＣｕを載置し、これを耐火容器内に充填し、Ｃｕを加熱溶融して成形体中に含浸させることにより溶浸体を形成し、この溶浸体を真空中において４５０℃以上６００℃以下の温度で３０分以上３時間以内の時間加熱する。また別の電気接点部材の他の製造方法として、前記のＣｒ粉末と前記のＣｕ粉末からなる成形体を真空中又は不活性雰囲気中においてＣｕの融点以下で焼結することにより焼結体を形成し、この焼結体を真空中において４５０℃以上６００℃以下の温度で
３０分以上３時間以内の時間加熱することとする。４５０℃以上６００℃以下の温度で行う熱処理は真空中で行うことによって、電気接点部材の含有ガス量を適正値に制御することができる。また、熱処理温度が４５０℃より低いと同様の効果を得るための熱処理時間が膨大となり生産性の低下を招き、６００℃より高いと上記の効果が得られない。熱処理温度を４５０℃以上６００℃以下の範囲とすることで、３０分以上３時間以内という比較的生産性の良い処理時間で上記の効果を得ることができるのである。また、上記の電気接点部材の製造方法において、成形体はＣｒ粉末とＣｕ粉末とを含む混合粉末を１２０〜５００ＭＰａで加圧成形することとする。成形圧力が１２０ＭＰａより小さいと成形体密度が小さくなり成形体が崩れやすく、これより大きいと成形体にラミネーション割れが発生し、健全な成形体が得られないことによる。
【００１４】
また真空バルブを、上記に記載の電気接点部材の製法によって製造された電気接点部材を用いて固定側電極及び可動側電極を形成する。これにより真空バルブは、真空容器内に固定側電極と可動側電極とを備え、この固定側電極及び可動側電極の少なくとも一方を上記の電気接点部材とすることで、遮断性能と耐電圧特性、並びに耐溶着性を両立する優れた性能を発揮することができる。
【００１５】
また、本発明の真空バルブは、固定側電極及び可動側電極として溶浸法あるいは粉末冶金法で得られた電気接点部材を用い、組み立てられた後の真空バルブを４５０℃以上６００℃以下の温度で３０分以上３時間以内の時間加熱してもよく、これにより電気接点部材のみを熱処理した場合と同様の効果が得られ、上記と同様に遮断性能と耐電圧特性、並びに耐溶着性を両立する優れた性能を発揮することができる。なお、電気接点部材が位置する真空バルブ内は真空雰囲気に保たれているので、真空バルブを熱処理する際の雰囲気は大気中でもよく、生産コストを低く抑えることができ、電気接点部材の含有ガス量は適正に保たれる。但し、外観保持のための表面酸化防止策として、真空中や不活性ガス流中で熱処理してもよい。
【００１６】
以下に実際に電極接点部材，電極，真空バルブ，真空遮断器を用いた例を示し、詳細に説明する。
【００１７】
（実施例１）
第１の実施例として、Ｃｒ量が１５，２５及び４０重量％の電気接点部材を作製した。また、比較のために、Ｃｒが５，１０，５０及び６０重量％の電気接点部材を併せて作製した。これらの電気接点部材の製造方法は次の通りである。
【００１８】
まず、Ｃｒ粉末とＣｕ粉末とを、所望の配合比でＶ型混合器により混合した。この際用いられたＣｒ粉末には酸素が１１００ｐｐｍ 、Ａｌが８００ｐｐｍ 、Ｓｉが４４０ｐｐｍ 含まれており、粒径は１０４μｍ以下であった。また用いたＣｕ粉末は粒径が８０μｍ以下の電解粉であった。
【００１９】
次にこの混合粉を直径６０ｍｍの金型に充填し、油圧プレスにより２５０ＭＰａの圧力を直径６０ｍｍの円面にかけ加圧成形した。成形体の寸法はおよそ直径６０ｍｍ×厚さ１２ｍｍで、相対密度はＣｒとＣｕの配合比で異なるが、およそ６５〜
７７％であった。これを６．７×１０−３Ｐａ 以下の真空中で１０５０℃×１２０分間加熱し、焼結体を得た。さらに、得られた焼結体を６．７×１０−３Ｐａ 以下の真空中において、５００℃で２時間加熱する熱処理を施し、電気接点部材を作製した。作製した電気接点部材の組成，相対密度，Ｃｕマトリックス中のＣｒ固溶量及び比抵抗を表１に示す。なお表１には比較のため、５００℃×２時間の熱処理前後のＣｒ固溶量及び比抵抗を併せて示す。
【００２０】
【表１】
Ｃｒの配合量が多いほど、熱処理前のＣｒ固溶量が多くなっていることがわかる。これは焼結過程で加熱される際、ＣｒがＣｒ粉表面からＣｕマトリックス中に固溶するためである。熱処理後のＣｒ固溶量は、Ｃｒ配合量に関わらず数１０ｐｐｍ レベルに低減される。これはＣｕマトリックス中に固溶したＣｒが熱処理により晶出するためである。また、いずれの組成においても固溶Ｃｒの晶出により熱処理前に比べて熱処理後の比抵抗が小さくなる。この熱処理後の比抵抗の値ｙ（μΩ・ｃｍ）は、Ｃｒの重量分率ｘに基づいて以下の（１）式によって求められる値以下となっている。一方で、比抵抗が（１）式で求められる値ｙ（μΩ・ｃｍ）より大きいと、上述したように導電率の低下により遮断性能が低下する結果となる。
【００２２】
ｙ＝２５．４ｘ４−６２．１ｘ３＋３２．６ｘ２＋６．９ｘ＋１．６９８ …（１）
（但し、０．１５≦ｘ≦０．４）
以上から、本発明における電気接点部材は、真空中において４５０℃以上６００℃以下の温度で３０分以上３時間以内の時間加熱する熱処理を施すことにより、Ｃｕマトリックス中のＣｒ固溶量が５００ｐｐｍ 以下となり、比抵抗が小さくなるため電気接点部材の導電性を良好に保ち、優れた遮断性能を確保することができる。但し、Ｃｕ中におけるＣｒ固溶量が５００ｐｐｍ を超えると、高導電性成分であるＣｕマトリックスの比抵抗が大きくなり、導電性が低下してしまう。
【００２３】
以上により、遮断性能，耐電圧特性及び耐溶着性能を兼ね備えた電極を得ることができる。なお、以上の傾向は、電気接点部材を溶浸法で作製した場合にも確認された。
【００２４】
（実施例２）
本実施例では実施例１で作製した表１に示す電気接点部材を用いて真空バルブに適用するための電極を作製した。図１は作製した電極の構造を示す図である。図１における電極は、発生したアークに駆動力を与えてアークを一箇所に停滞させないための３本のスパイラル溝２及び中央に設けられる凹部を有し羽根型に分離された形状を有する電気接点１と、電気接点１を補強するステンレス製の補強板３と、電気接点１と補強板３に嵌め合わされる電極棒４と、を有して構成される。なお、電極接点１と補強板３との間、補強板３と電極棒４の間には、これらを接着させるろう材５が存在する。なお、スパイラル溝は３本以上であれば望ましく、特に本実施例の本数に限られることはない。なお図１に係る電極は真空バルブの固定側電極，可動側電極いずれにも適用可能である。
【００２５】
電極の作製方法は次の通りである。実施例１で作製した電気接点部材を機械加工により所望形状に加工して電気接点１を得る。電極棒４を無酸素銅で、また、補強板３をＳＵＳ３０４であらかじめ機械加工により作製しておき、電気接点１及び補強板３の中央孔と電極棒４の凸部とを、ろう材５を介して嵌め合わせ、また電気接点１と補強板３との間にもろう材５を載置し、８．２×１０−４Ｐａ 以下の真空中で９８０℃×８分間加熱し、図１に示す電極を作製した。なお、この電極は定格電圧７．２ｋＶ ，定格電流６００Ａ，定格遮断電流２０ｋＡ用の真空バルブに用いられる電極である。
【００２６】
以上により、遮断性能，耐電圧特性及び耐溶着性能を兼ね備えた電極を得ることができる。
【００２７】
（実施例３）
本実施例では、実施例２で作製した電極を搭載した真空バルブを作製した。真空バルブの仕様は、定格電圧７．２ｋＶ ，定格電流６００Ａ，定格遮断電流２０ｋＡである。
【００２８】
図２は本実施例に係る真空バルブの構造を示す図である。図２における真空バルブは固定側電極接点１ａ，固定側補強板３ａ，固定側電極棒４ａ、を有する固定側電極６ａと、可動側電極接点１ｂ，可動側補強板３ｂ，可動側電極棒４ｂを有し、固定側電極６ａと対向して配置される可動側電極６ｂと、遮断時の金属蒸発等による飛散を防ぐ側部のシールド７及び可動側シールド８と、可動側シールド８を介して可動側電極６ｂとろう付け接合される可動側ホルダー１２と、真空バルブ内を高真空で保持できるよう封止するための固定側端板９ａ，可動側端板９ｂ，絶縁筒１３と、を有している。なお可動側端板９ｂと可動側ホルダー１２の間には摺動部分を支えるためのガイド１１が設けられ、さらに可動側シールド８と可動側端板９ｂの間にはベローズ１０が設けられており、真空バルブ内を高真空に保ったまま可動側ホルダー１２を上下させ、固定側電極６ａと可動側電極６ｂを開閉させることができる。
【００２９】
本実施例では、固定側電極６ａ及び可動側電極６ｂに、実施例２で作製した図１に示す構造の電極を用いて、図２に示す真空バルブを作製した。
【００３０】
以上により、遮断性能，耐電圧特性及び耐溶着性能を兼ね備えた真空バルブを得ることができた。
【００３１】
（実施例４）
本実施例では実施例１で作製した表１に示す電気接点部材のうち、熱処理なしの部材（試料番号：Ａ１，Ｂ１，Ｃ１，Ｄ１，Ｅ１，Ｆ１，Ｇ１）を用いて電極を作製し、これを搭載した真空バルブをさらに作製した。そしてこの真空バルブに対して大気中において５００℃で２時間加熱する熱処理を施した。なお、電極及び真空バルブの作製方法は、それぞれ実施例２及び実施例３と同様である。これら真空バルブを真空遮断器に組み込んで、各種性能試験を実施した。この結果を表２に示す。なお、表２におけるそれぞれの性能は、試料番号Ｃ１（組成：
１５Ｃｒ−８５Ｃｕ，電気接点部材及び真空バルブの熱処理なし）の値を１として相対比較して表したものである。
【００３２】
【表２】
電気接点部材のＣｒ配合量が１５重量％以上の場合、電気接点部材あるいは真空バルブに対して熱処理を施すと、遮断性能が向上する。これは、電気接点部材の製造過程においてＣｕマトリックス中に固溶したＣｒあるいは不純物が、熱処理により晶出され、導電性が向上したことによる。電気接点部材のＣｒ配合量が１５重量％より少ない場合において遮断性能の向上が見られないのはＣｒ配合量が少ないために電気接点部材の製造過程におけるＣｕマトリックス中へのＣｒの固溶が少ないためである。なおいずれの組成においても熱処理による耐電圧性能及び耐溶着性能の変化は見られなかった。
【００３４】
一方、電気接点部材のＣｒ配合量が４０重量％以上の場合において、電気接点部材及び真空バルブへの熱処理がない場合には、Ｃｒ量が多いために電気接点部材の導電率が小さくなり、遮断性能は低下する。しかしながら、試料番号Ｅ１，Ｅ２のように熱処理により遮断性能が向上するので、優れた耐電圧特性及び耐溶着性を維持しながら、十分な遮断性能を有する真空バルブを得ることができる。但しＣｒ配合量がこの場合においても４０重量％を超える場合は、たとえ熱処理を加えた場合であっても、Ｃｒ量が多すぎて熱処理による導電率向上の効果が十分ではない。
【００３５】
なお、真空バルブに対する熱処理を真空中及びアルゴンなどの不活性ガス流中で行った際にも、上記と同様の効果が確認された。
【００３６】
以上から、本発明に係わる電気接点部材及び真空バルブは、優れた遮断性能，耐電圧特性及び耐溶着性を併せ持つことが実証された。
【００３７】
【発明の効果】
以上により安定した遮断性能，耐電圧特性及び耐溶着性能を兼ね備えた電気接点部材、それを用いた真空バルブ、それらを用いた真空遮断器を提供することができる。
【図面の簡単な説明】
【図１】本発明の第２実施例に係わる電極の構造を表す図。
【図２】本発明の第３実施例に係わる真空バルブの構造を表す図。
【符号の説明】
１…電気接点、１ａ…固定側電気接点、１ｂ…可動側電気接点、２…スパイラル溝、３，３ａ，３ｂ…補強板、４，４ａ，４ｂ…電極棒、５…ろう材、６ａ…固定側電極、６ｂ…可動側電極、７…シールド、８…可動側シールド、９ａ…固定側端板、９ｂ…可動側端板、１０…ベローズ、１１…ガイド、１２…可動側ホルダー、１３…絶縁筒。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electrical contact member, a vacuum valve using the same, a vacuum circuit breaker using the same, and a method for manufacturing the same.
[0002]
[Prior art]
The electrode structure in the vacuum valve installed in the vacuum circuit breaker has a pair of fixed-side electrodes and movable-side electrodes. The structure of the fixed side electrode and the movable side electrode has an electric contact and an electrode rod connected to the electric contact, and a plate of stainless steel or the like is often provided as a reinforcing plate on the back surface of the electric contact.
[0003]
Electrical contacts are directly exposed to arcs to switch on and off high voltages and large currents. The characteristics required of the electric contact include a large breaking capacity, a high withstand voltage value, and excellent welding resistance. In particular, as the voltage distribution increases, the vacuum circuit breaker, the vacuum switch, and the like are required to achieve both high current interruption and high withstand voltage characteristics and welding performance.
[0004]
As the electrical contact member for interrupting a large current and a high voltage, a composite metal material of Cr-Cu is often used. As a method of manufacturing this electrical contact member, there are a so-called powder metallurgy method in which a metal powder of each component or a mixed powder thereof is formed and sintered into a simple shape such as a disk with a predetermined composition, and a Cu skeleton is formed on the formed skeleton. Alternatively, there is a so-called infiltration method in which the molten alloy is impregnated and machined to form a predetermined shape. These manufacturing methods are described in JP-A-9-213153, Japanese Patent Application No. 2000-188045, and the like. .
[0005]
[Problems to be solved by the invention]
However, even with the electric contact member described in the above publication, there is still a problem to be solved in satisfying all of these characteristics, and in general, emphasis is placed on particularly important characteristics depending on the application, Other properties use materials that have been sacrificed to some extent. For example, in the case of a composite metal material of Cr-Cu, it is necessary to have a high conductivity in order to increase the breaking capacity. However, on the other hand, the amount of Cr, which is a component for improving the withstand voltage performance, is reduced, so that the withstand voltage value and the welding resistance are reduced. Conversely, by increasing the amount of Cr, the withstand voltage value and the welding resistance can be improved. However, if the amount of Cr is increased, the amount of Cu is reduced, so that the electrical conductivity is reduced, and the blocking performance becomes insufficient. It was extremely difficult to achieve both current interruption performance, high withstand voltage characteristics, and welding resistance.
[0006]
As described above, an object of the present invention is to provide an electric contact member having stable breaking performance, withstand voltage characteristics and welding resistance, a vacuum valve using the same, and a vacuum circuit breaker using the same.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the electrode contact member has 15 to 40% by weight of Cr, 60 to 85% by weight of Cu, and unavoidable impurities, and has a Cr solid solution amount of 500 ppm or less in Cu. There is a feature. Thereby, even if the content of the refractory metal component is increased in order to improve the withstand voltage characteristics and the welding performance, the conductivity can be improved, and the breaking performance can be ensured. Since the conductivity can be improved even when the amount of Cr, which is a refractory metal, is increased, it is possible to manufacture a vacuum valve having both blocking performance, withstand voltage performance, and welding performance.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
The present inventors performed heat treatment in a high vacuum atmosphere on electrical contact members obtained by a powder metallurgy method, an infiltration method, or the like, so that a refractory metal component or other impurities dissolved in a matrix in a manufacturing process. Were found to be crystallized, the conductivity of the Cu matrix was improved, and the blocking performance was improved. Thereby, even if the content of the refractory metal component is increased in order to improve the withstand voltage characteristics and the welding resistance, the conductivity can be improved, and the blocking performance can be ensured. Similar effects can be obtained when a vacuum valve using an electrical contact member manufactured by an infiltration method or a sintering method is subjected to a heat treatment in the atmosphere, in an inert gas flow, or in a vacuum. I found that. Therefore, since the conductivity can be improved even if the amount of Cr, which is a refractory metal, is increased, it is possible to manufacture a vacuum valve having both blocking performance, withstand voltage performance and welding performance.
[0009]
As a specific mode, the electric contact member is made of 15 to 40% by weight of Cr, 60 to 85% by weight of Cu, and unavoidable impurities, and has a Cr solid solution amount of 500 ppm or less in Cu. Alternatively, it is composed of 15 to 40% by weight of Cr, 60 to 85% by weight of Cu, and unavoidable impurities, and the specific resistance y (μΩ · cm) is obtained by the following equation (1) based on the weight fraction x of Cr. Shall be less than or equal to
[0010]
y = 25.4x 4 -62.1x 3 + 32.6x 2 + 6.9x + 1.698 ... (1)
(However, 0.15 ≦ x ≦ 0.4)
Cr containing 50 to 2000 ppm of oxygen, 50 to 3000 ppm of Al, and 400 to 2500 ppm of Si is used as an impurity. These impurity components are useful for obtaining an excellent arc-extinguishing effect at the time of interruption, and thereby the interruption performance is stabilized. Alternatively, it is useful for the electrical contact member to contain 400 to 5000 ppm of oxygen. Note that Al and Si may each exist as an oxide. This is because excellent welding resistance and withstand voltage characteristics can be obtained by uniformly dispersing hard fine Al and Si oxides having a high melting point. However, if the oxygen content is less than 400 ppm, the movement speed of the arc is reduced, and it tends to stagnate at a specific location on the electrode, and the possibility of interruption cannot be increased. The volume is high and the arc interruption through the gas causes uninterruptibility.
[0011]
The vacuum valve is provided with a fixed side electrode and a movable side electrode in a vacuum vessel, and the above-mentioned electric contact member is used for the fixed side electrode and the movable side electrode.
[0012]
Further, a vacuum circuit breaker is provided with a vacuum valve having a fixed side electrode and a movable side electrode in a vacuum vessel, and an insulation connected outside the vacuum valve to each of the fixed side electrode and the movable side electrode in the vacuum valve. Opening / closing means for driving the movable-side electrode via a rod is provided, and the vacuum valve in the vacuum circuit breaker includes the vacuum valve described above.
[0013]
Further, as a method of manufacturing this electrical contact member, Cu is placed on a molded body composed of Cr powder and Cu powder, filled in a refractory container, and heated and melted to impregnate the molded body with Cu. An infiltration body is formed, and this infiltration body is heated in a vacuum at a temperature of 450 ° C. or more and 600 ° C. or less for a period of 30 minutes or more and 3 hours or less. As another method for producing another electrical contact member, a sintered body is formed by sintering a compact made of the Cr powder and the Cu powder below the melting point of Cu in a vacuum or in an inert atmosphere. Then, this sintered body is heated in a vacuum at a temperature of 450 ° C. or more and 600 ° C. or less for a period of 30 minutes or more and 3 hours or less. By performing the heat treatment at a temperature of 450 ° C. or more and 600 ° C. or less in a vacuum, the gas content of the electrical contact member can be controlled to an appropriate value. On the other hand, when the heat treatment temperature is lower than 450 ° C., the heat treatment time for obtaining the same effect becomes enormous, resulting in a decrease in productivity. When the heat treatment temperature is higher than 600 ° C., the above effect cannot be obtained. By setting the heat treatment temperature in the range of 450 ° C. or more and 600 ° C. or less, the above effect can be obtained in a relatively good productivity time of 30 minutes or more and 3 hours or less. In the above method for manufacturing an electrical contact member, the compact is formed by pressing a mixed powder containing a Cr powder and a Cu powder at a pressure of 120 to 500 MPa. If the molding pressure is less than 120 MPa, the density of the molded body becomes small and the molded body is easily broken. If the molding pressure is larger than this, lamination cracks occur in the molded body and a sound molded body cannot be obtained.
[0014]
The fixed electrode and the movable electrode are formed in the vacuum valve by using the electric contact member manufactured by the above-described method of manufacturing the electric contact member. Thereby, the vacuum valve has a fixed side electrode and a movable side electrode in a vacuum vessel, and at least one of the fixed side electrode and the movable side electrode is the above-mentioned electric contact member, so that the breaking performance and the withstand voltage property, In addition, it is possible to exhibit excellent performance satisfying both welding resistance.
[0015]
In addition, the vacuum valve of the present invention uses electrical contact members obtained by infiltration or powder metallurgy as the fixed-side electrode and the movable-side electrode, and operates the assembled vacuum valve at a temperature of 450 ° C to 600 ° C. For 30 minutes or more and up to 3 hours, whereby the same effect as when only the electrical contact member is heat-treated can be obtained, and in the same manner as above, the breaking performance, the withstand voltage characteristic, and the welding resistance can both be achieved. Excellent performance can be demonstrated. In addition, since the inside of the vacuum valve where the electrical contact member is located is maintained in a vacuum atmosphere, the atmosphere for heat treatment of the vacuum valve may be in the air, so that production costs can be kept low, and the gas content of the electrical contact member can be reduced. Is kept properly. However, heat treatment may be performed in a vacuum or in an inert gas flow as a measure for preventing surface oxidation for maintaining the appearance.
[0016]
Hereinafter, an example in which an electrode contact member, an electrode, a vacuum valve, and a vacuum circuit breaker are actually used will be shown and described in detail.
[0017]
(Example 1)
As a first example, electrical contact members having Cr amounts of 15, 25 and 40% by weight were produced. For comparison, electrical contact members with 5, 10, 50 and 60% by weight of Cr were also prepared. The method for manufacturing these electrical contact members is as follows.
[0018]
First, Cr powder and Cu powder were mixed in a desired mixing ratio by a V-type mixer. The Cr powder used at this time contained 1100 ppm of oxygen, 800 ppm of Al, and 440 ppm of Si, and had a particle size of 104 μm or less. The Cu powder used was an electrolytic powder having a particle size of 80 μm or less.
[0019]
Next, the mixed powder was filled in a mold having a diameter of 60 mm, and a pressure of 250 MPa was applied to a circular surface having a diameter of 60 mm by a hydraulic press to perform pressure molding. The size of the compact is about 60 mm in diameter x 12 mm in thickness, and the relative density varies depending on the mixing ratio of Cr and Cu.
77%. This was heated in a vacuum of 6.7 × 10 −3 Pa or less at 1050 ° C. for 120 minutes to obtain a sintered body. Further, the obtained sintered body was subjected to a heat treatment of heating at 500 ° C. for 2 hours in a vacuum of 6.7 × 10 −3 Pa or less to produce an electrical contact member. Table 1 shows the composition, the relative density, the amount of Cr dissolved in the Cu matrix, and the specific resistance of the manufactured electrical contact members. For comparison, Table 1 also shows the amount of solid solution of Cr and the specific resistance before and after the heat treatment at 500 ° C. for 2 hours.
[0020]
[Table 1]
It can be seen that the greater the amount of Cr added, the greater the amount of Cr solid solution before heat treatment. This is because Cr is dissolved in the Cu matrix from the surface of the Cr powder when heated in the sintering process. The Cr solid solution amount after the heat treatment is reduced to the level of several tens of ppm regardless of the Cr content. This is because Cr dissolved in the Cu matrix is crystallized by heat treatment. Further, in any of the compositions, the specific resistance after the heat treatment is smaller than that before the heat treatment due to crystallization of solid solution Cr. The value y (μΩ · cm) of the specific resistance after the heat treatment is equal to or less than the value obtained by the following equation (1) based on the weight fraction x of Cr. On the other hand, if the specific resistance is larger than the value y (μΩ · cm) determined by the expression (1), the cutoff performance is reduced due to the decrease in conductivity as described above.
[0022]
y = 25.4x 4 -62.1x 3 + 32.6x 2 + 6.9x + 1.698 ... (1)
(However, 0.15 ≦ x ≦ 0.4)
From the above, the electrical contact member of the present invention is subjected to a heat treatment of heating at a temperature of 450 ° C. or more and 600 ° C. or less for 30 minutes or more and 3 hours or less in a vacuum, so that the amount of Cr dissolved in the Cu matrix is 500 ppm or less. And the specific resistance is reduced, so that the conductivity of the electrical contact member can be kept good, and excellent breaking performance can be secured. However, if the amount of Cr dissolved in Cu exceeds 500 ppm, the specific resistance of the Cu matrix, which is a highly conductive component, increases, and the conductivity decreases.
[0023]
As described above, it is possible to obtain an electrode having both the breaking performance, the withstand voltage characteristic and the welding resistance. The above tendency was also confirmed when the electrical contact member was manufactured by the infiltration method.
[0024]
(Example 2)
In this embodiment, an electrode to be applied to a vacuum valve was manufactured using the electrical contact members shown in Table 1 manufactured in the first embodiment. FIG. 1 is a diagram showing the structure of the manufactured electrode. The electrode shown in FIG. 1 has three spiral grooves 2 for applying a driving force to the generated arc so that the arc does not stay at one place, and an electric contact having a concave shape provided at the center and having a blade-shaped shape. 1, a reinforcing plate 3 made of stainless steel for reinforcing the electric contact 1, and an electrode rod 4 fitted to the electric contact 1 and the reinforcing plate 3. There is a brazing material 5 between the electrode contacts 1 and the reinforcing plate 3 and between the reinforcing plate 3 and the electrode rods 4 for bonding them. The number of spiral grooves is desirably three or more, and is not particularly limited to the number in the present embodiment. The electrode according to FIG. 1 is applicable to both the fixed side electrode and the movable side electrode of the vacuum valve.
[0025]
The method for manufacturing the electrode is as follows. The electrical contact member manufactured in Example 1 is processed into a desired shape by machining to obtain the electrical contact 1. The electrode rod 4 is made of oxygen-free copper, the reinforcing plate 3 is made of SUS304 by machining in advance, and the central hole of the electric contact 1 and the reinforcing plate 3 and the convex part of the electrode rod 4 are formed with the brazing material 5. The brazing material 5 is also placed between the electric contact 1 and the reinforcing plate 3 and heated at 980 ° C. for 8 minutes in a vacuum of 8.2 × 10 −4 Pa or less, as shown in FIG. The electrodes shown were prepared. This electrode is used for a vacuum valve for a rated voltage of 7.2 kV, a rated current of 600 A, and a rated breaking current of 20 kA.
[0026]
As described above, it is possible to obtain an electrode having both the breaking performance, the withstand voltage characteristic and the welding resistance.
[0027]
(Example 3)
In this embodiment, a vacuum valve equipped with the electrode manufactured in Embodiment 2 was manufactured. The specifications of the vacuum valve are a rated voltage of 7.2 kV, a rated current of 600 A, and a rated breaking current of 20 kA.
[0028]
FIG. 2 is a view showing the structure of the vacuum valve according to the present embodiment. The vacuum valve in FIG. 2 includes a fixed electrode 6a having a fixed electrode contact 1a, a fixed reinforcing
[0029]
In this example, the vacuum valve shown in FIG. 2 was manufactured using the electrode having the structure shown in FIG. 1 manufactured in Example 2 as the fixed-side electrode 6a and the movable-
[0030]
As described above, a vacuum valve having both the breaking performance, the withstand voltage characteristic, and the welding resistance can be obtained.
[0031]
(Example 4)
In the present embodiment, among the electrical contact members shown in Table 1 manufactured in Example 1, electrodes were manufactured using members (sample numbers: A1, B1, C1, D1, E1, F1, and G1) without heat treatment. A vacuum valve equipped with this was further manufactured. The vacuum valve was subjected to a heat treatment of heating at 500 ° C. for 2 hours in the atmosphere. The method for manufacturing the electrode and the vacuum valve is the same as in Example 2 and Example 3, respectively. Various performance tests were conducted by incorporating these vacuum valves into a vacuum circuit breaker. Table 2 shows the results. In addition, each performance in Table 2 shows the sample number C1 (composition:
15Cr-85Cu, no heat treatment of the electrical contact member and the vacuum valve), and the relative value is expressed as 1.
[0032]
[Table 2]
When the amount of Cr in the electric contact member is 15% by weight or more, heat treatment is performed on the electric contact member or the vacuum valve to improve the breaking performance. This is because Cr or impurities dissolved in the Cu matrix during the manufacturing process of the electrical contact member are crystallized by the heat treatment, and the conductivity is improved. When the amount of Cr in the electrical contact member is less than 15% by weight, the improvement in the breaking performance is not seen. That's why. In any of the compositions, no change was observed in the withstand voltage performance and the welding resistance performance due to the heat treatment.
[0034]
On the other hand, when the amount of Cr in the electric contact member is 40% by weight or more, and when there is no heat treatment to the electric contact member and the vacuum valve, the electric conductivity of the electric contact member becomes small due to the large amount of Cr, and the electric contact member is cut off. Performance degrades. However, since the heat-cutting performance is improved by the heat treatment as in the sample numbers E1 and E2, it is possible to obtain a vacuum valve having a sufficient interrupting performance while maintaining excellent withstand voltage characteristics and welding resistance. However, if the amount of Cr exceeds 40% by weight even in this case, even if a heat treatment is applied, the amount of Cr is too large and the effect of improving the conductivity by the heat treatment is not sufficient.
[0035]
The same effect as described above was confirmed when the heat treatment for the vacuum valve was performed in a vacuum and in a flow of an inert gas such as argon.
[0036]
From the above, it was proved that the electric contact member and the vacuum valve according to the present invention have excellent breaking performance, withstand voltage characteristics and welding resistance.
[0037]
【The invention's effect】
As described above, it is possible to provide an electric contact member having stable breaking performance, withstand voltage characteristics and welding resistance, a vacuum valve using the same, and a vacuum circuit breaker using the same.
[Brief description of the drawings]
FIG. 1 is a diagram showing a structure of an electrode according to a second embodiment of the present invention.
FIG. 2 is a view illustrating a structure of a vacuum valve according to a third embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Electrical contact, 1a ... Fixed side electrical contact, 1b ... Movable side electrical contact, 2 ... Spiral groove, 3, 3a, 3b ... Reinforcement plate, 4, 4a, 4b ... Electrode rod, 5 ... Brazing material, 6a ... Fixed Side electrode, 6b: movable electrode, 7: shield, 8: movable shield, 9a: fixed end plate, 9b: movable end plate, 10: bellows, 11: guide, 12: movable holder, 13: insulation Tube.
Claims (13)
６０〜８５重量％のＣｕと、不可避の不純物とを有し、
Ｃｕ中のＣｒ固溶量が５００ｐｐｍ 以下であることを特徴とする電気接点部材。15 to 40% by weight of Cr,
60 to 85% by weight of Cu and unavoidable impurities,
An electrical contact member characterized in that the amount of solid solution of Cr in Cu is 500 ppm or less.
ｙ＝２５．４ｘ４−６２．１ｘ３＋３２．６ｘ２＋６．９ｘ＋１．６９８ …（１）
（但し、０．１５≦ｘ≦０．４）It is composed of 15 to 40% by weight of Cr, 60 to 85% by weight of Cu and unavoidable impurities, and has a specific resistance y (μΩ · cm) determined by the following equation (1) based on the weight fraction x of Cr. An electric contact member characterized by the following.
y = 25.4x 4 -62.1x 3 + 32.6x 2 + 6.9x + 1.698 ... (1)
(However, 0.15 ≦ x ≦ 0.4)
前記焼結体若しくは溶浸体を４５０℃以上６００℃以下の温度で加熱する工程と、を有することを特徴とする電気接点の製造方法。Forming a sintered body or infiltrated body having 15 to 40% by weight of Cr, 60 to 85% by weight of Cu, and unavoidable impurities;
Heating the sintered body or infiltrated body at a temperature of 450 ° C. or more and 600 ° C. or less.
前記作製された成形体に前記Ｃｕを載置し、前記Ｃｕを加熱溶融して前記成形体中に含浸させて溶浸体を形成する工程と、を有することを特徴とする請求項５記載の電気接点の製造方法。The step of forming the infiltrated body is a step of producing a molded body composed of Cr powder and Cu powder and unavoidable impurities,
The method according to claim 5, further comprising the steps of: placing the Cu on the produced compact, heating and melting the Cu, and impregnating the Cu into the compact to form an infiltrated body. Manufacturing method of electrical contacts.
真空中にて行われることを特徴とする請求項６記載の電気接点の製造方法。The step of heating the infiltration body at 450 ° C. or more and 600 ° C. or less,
7. The method according to claim 6, wherein the method is performed in a vacuum.
３０分以上３時間以内の時間加熱することを特徴とする請求項６記載の電気接点の製造方法。The step of heating the infiltration body at 450 ° C. or more and 600 ° C. or less,
7. The method for manufacturing an electrical contact according to claim 6, wherein the heating is performed for a period of 30 minutes to 3 hours.
真空中にて３０分以上３時間以内の時間加熱することを特徴とする請求項６記載の電気接点の製造方法。The step of heating the infiltration body at 450 ° C. or more and 600 ° C. or less,
7. The method for manufacturing an electrical contact according to claim 6, wherein the heating is performed in a vacuum for at least 30 minutes and no more than 3 hours.
真空中にて行われることを特徴とする請求項１０記載の電気接点の製造方法。The step of heating the sintered body at 450 ° C. or more and 600 ° C. or less,
The method according to claim 10, wherein the method is performed in a vacuum.
３０分以上３時間以内の時間加熱することを特徴とする請求項１０記載の電気接点の製造方法。The step of heating the sintered body at 450 ° C. or more and 600 ° C. or less,
The method for manufacturing an electrical contact according to claim 10, wherein the heating is performed for a period of 30 minutes to 3 hours.
真空中にて３０分以上３時間以内の時間加熱することを特徴とする請求項１０記載の電気接点の製造方法。The step of heating the sintered body at 450 ° C. or more and 600 ° C. or less,
The method for manufacturing an electrical contact according to claim 10, wherein the heating is performed in a vacuum for a period of 30 minutes to 3 hours.
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| JP2002241293A JP2004076141A (en) | 2002-08-22 | 2002-08-22 | Vacuum valve used for vacuum interrupter, and manufacturing method of electric contact |
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| JP2002241293A JP2004076141A (en) | 2002-08-22 | 2002-08-22 | Vacuum valve used for vacuum interrupter, and manufacturing method of electric contact |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009149966A (en) * | 2007-11-30 | 2009-07-09 | Jfe Steel Corp | METHOD FOR PRODUCING Cr-Cu ALLOY SHEET |
| CN115094358A (en) * | 2022-06-30 | 2022-09-23 | 国网河南省电力公司电力科学研究院 | Electrical contact material surface nanocrystallization method and device |
-
2002
- 2002-08-22 JP JP2002241293A patent/JP2004076141A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009149966A (en) * | 2007-11-30 | 2009-07-09 | Jfe Steel Corp | METHOD FOR PRODUCING Cr-Cu ALLOY SHEET |
| CN115094358A (en) * | 2022-06-30 | 2022-09-23 | 国网河南省电力公司电力科学研究院 | Electrical contact material surface nanocrystallization method and device |
| CN115094358B (en) * | 2022-06-30 | 2023-06-09 | 国网河南省电力公司电力科学研究院 | Surface nanocrystallization method and device for electrical contact material |
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