JP4081366B2

JP4081366B2 - Proportional solenoid valve and its assembly method

Info

Publication number: JP4081366B2
Application number: JP2002355121A
Authority: JP
Inventors: 庸夫丹羽; 知樹只腰; 成伸西田
Original assignee: CKD Corp
Current assignee: CKD Corp
Priority date: 2002-12-06
Filing date: 2002-12-06
Publication date: 2008-04-23
Anticipated expiration: 2022-12-06
Also published as: JP2004183863A

Description

【０００１】
【発明の属する技術分野】
本発明は、固定鉄心が発生する吸引力によりプランジャを無摺動で作動させ、弁体のストローク量を制御する電磁比例弁に関する。
【０００２】
【従来の技術】
従来、半導体製造工程では、微細加工が進み、プロセスガスなどの制御流体を電磁比例弁で精密に制御している。
電磁比例弁には、例えば、プランジャ方式を採用するものがある。プランジャ方式の電磁弁は、コイルを巻回したコイルボビンに固定鉄心を固設するとともに、固定鉄心と同軸上に棒状プランジャを摺動可能に挿入し、棒状プランジャの先端部に固定した弁体を弁座に当接又は離間させるものである。こうしたプランジャ方式の電磁弁は、棒状プランジャがコイルへの印加電流に比例してコイルボビン内を摺動し、弁体を弁座から分離させて、制御流体の流量を制御する。このとき、棒状プランジャは、固定鉄心と対向する面とコイルボビンに挿入された外周面とに吸引力が作用するため、少ない通電量で弁体のストローク量を調整できる利点がある。
【０００３】
ところが、プランジャ方式では、棒状プランジャの摺動時にパーティクルを生じ、製品品質に悪影響を与えたり、また、棒状プランジャをコイルに挿入する構造であるため、装置全体の高さが高く、装置サイズが大型化する欠点がある。
【０００４】
こうした欠点を補うべく、フラッパ方式を採用する電磁比例弁が提案されている。フラッパ方式は、コイルへの印加電流による磁力に比例してプランジャを無摺動で作動させることにより、弁体のストローク量を制御するものであり、パーティクルの発生を抑制するとともに、装置サイズをコンパクトにしている。
【０００５】
図７は、フラッパ方式を採用する電磁比例弁１００の断面図である。
電磁比例弁１００は、ボディ１０１に入口流路１０３と出口流路１０２とが形成されており、その連通部分に弁室１０４が設けられている。弁室１０４には、出口流路１０２と連通する開口部の周りに弁座１０５が設けられている。また、ボディ１０１には、保持部材１０６が嵌め込まれ、ボディ１０１と保持部材１０６との間に板バネ１０７が狭持されている。板バネ１０７には、中心部に設けた孔１０８（図８参照）に対して弁シート１０９が弁シート押さえ板１１０を介して取り付けられ、板バネ１０７の取付荷重によって弁シート１０９を弁座１０５に押しつけている。
【０００６】
板バネ１０７は、図８の正面図に示すように、厚さ方向に対する弾性変形をスムーズにするため、孔１０８の周囲部において、内周固定部１１１と外周固定部１１２とが同心円状に形成されるとともに、内周固定部１１１と外周固定部１１２との間において、４枚の梁１１３の各々が略Ｓ字状に形成されている。
【０００７】
そして、板バネ１０７は、図９に示す弁部拡大断面図に示すように、内周固定部１１１が、弁シート１０９を装着されたプランジャ１１５と弁シート押さえ板１１０とに重ね合わされた状態で、プランジャ１１５に対して溶接接合されて固着されている（図中Ｐ１１参照）。これにより、板バネ１０７は、弁シート１０９及びプランジャ１１５と一体構造とされている。また、板バネ１０７の外周固定部１１２は、上スペーサ１２５と下スペーサ１２６との間に挟み込まれることにより、板バネ１０７をプランジャ１１５や弁座１０５等に対して位置合わせして支持している。
【０００８】
そして、保持部材１０６には、非磁性体からなる嵌装部材１１７が溶接接合により固着され、固定鉄心１１８を保持している。従って、コイル１１９に電流を供給すると、固定鉄心１１８や保持部材１０６が励磁され、板バネ１０７の復元力に抗してプランジャ１１５を吸引する。
【０００９】
こうした図７の電磁比例弁１００では、コイル１１９に所定の電流を供給して磁力を印加すると、図１０のバネ線図Ｋに示すように、プランジャ１１５の自重と板バネ１０７による押圧力の合成力に対して、コイル１１９に供給する電流に応じて固定鉄心１１８の発生する吸引力がバランスする点で、作動を行う。従って、例えば、板バネ１０７が所定のバネ定数を有することを前提として、コイル１１９に１５０ＡＴの印加磁力を与えると、プランジャ１１５にかかる力とＦ１点でバランスし、この点を制御流体の無圧時の開弁開始位置に設定し、弁変位Ｌ０の位置とする。さらに、例えば、印加磁力を３００ＡＴに強くすると、プランジャ１１５にかかる力とＦ２点でバランスし、弁はＬ１位置となり、Ｌ０からＬ１の距離が開弁の弁移動距離となる。尚、図７の電磁比例弁１００は、保持部材１０６をボディ１０１に嵌め込む量によりプランジャ１１５と固定鉄心１１８との間の距離を調整することによって、図１０に示す吸引力特性を変化させることができ、また、開弁開始位置Ｌ０を任意に設定することができる。
【００１０】
上記のように図７の電磁比例弁１００は、コイル１１９への印加電流による磁力に比例して弁の変位がなされて作動する。その際の印加電流による磁力に対して弁を流れる制御流体の流量は、図１０のバネ線図Ｋに示される吸引力特性に対して、図１１に示される流量制御特性となる。すなわち、このグラフは、電磁比例弁１００に１００〜１５０ＡＴの印加磁力を与えたときに開弁を開始するように設定したときのグラフであり、このような特性で制御流体が流れることが予め測定されているときには、所定の流量を得るための印加磁力を求めて制御することができ、また、流路を流れる制御流体の流量を測定して印加磁力を調整することにより、常に所定流量となるように制御することもできる。
【００１１】
従って、図７の電磁比例弁１００は、ボディ１０１の入口流路１０３に対して制御流体が供給されるが、図１１に示すように、コイル１１９に１００〜１５０ＡＴの印加磁力を与えるまでは、板バネ１０７の復元力により所定の取付荷重で弁シート１０９を弁座１０５に押しつけて、弁座１０５を閉じている。
【００１２】
ここで、コイル１１９に３００ＡＴの印加磁力を与えると、板バネ１０７の復元力に抗して、プランジャ１１５が固定鉄心１１８や保持部材１０６の磁力に吸引されて垂直上方向に移動するので、弁シート１０９が弁座１０５から分離し、弁座１０５を開く。このとき、電磁比例弁１００は、１５０％流量で制御流体を入口流路１０３から出口流路１０２へと供給する（例えば、特許文献１参照。）。
【特許文献１】
特開２００２−７１０４５号公報（第４〜５頁、第１図、第２図。）
【００１３】
【発明が解決しようとする課題】
しかしながら、図７に示す従来の電磁比例弁１００は、所望の流量制御特性が得られるように部品を組立調整することが困難である問題があった。
【００１４】
すなわち、電磁比例弁１００では、プランジャ１１５と固定鉄心１１８との間の距離を数十μｍ以内で設定することが要求されており、プランジャ１１５を数μｍの精度で作動調整して流量制御を行っている。こうした条件のもとで、組み立てられる電磁比例弁１００の全てが一定の流量制御特性を有するには、一定の吸引力特性を得る必要がある。吸引力特性は、プランジャ１１５と固定鉄心１１８との間の距離によって変化する。すなわち、プランジャ１１５と固定鉄心１１８との間の距離がばらつくと、図１０に示すように、バネ線図Ｋが傾き（板バネ１０７のバネ定数）を変えることなく、図中左右方向にばらついて（図中Ｋ１，Ｋ２参照）、開弁開始位置Ｌ０がずれる。開弁開始位置Ｌ０がずれると、図１１に示す流量制御特性も図中左右方向にばらつき、製品品質が一定しない。従って、電磁比例弁１００は、プランジャ１１５と固定鉄心１１８との間の距離を精密に設定するよう組み立て、開弁開始位置Ｌ０を定める必要がある。
【００１５】
この点、電磁比例弁１００では、図９に示すように、ボディ１０１に対して下スペーサ１２６、板バネ１０７、上スペーサ１２５を積み重ね、さらにボディ１０１に保持部材１０６を嵌め込むことにより、プランジャ１１５と固定鉄心１１８との間の距離の精度を絶対的に出している。そのため、ボディ１０１、弁座１０５、保持部材１０６、板バネ１０７等の部品公差は、プランジャ１１５と固定鉄心１１８との間の距離に直接影響し、製品品質にバラツキを生じさせていた。それに対して、部品の寸法精度を向上させて組立公差を小さくすることが考えられるが、プランジャ１１５が数μｍの微小量で作動する関係上、許容される部品公差は数μｍ未満であり、単に部品の寸法精度を向上させるだけでは十分に対応しきれない。
【００１６】
そのため、電磁比例弁１００では、ボディ１０１や保持部材１０６等の部品公差に応じて上スペーサ１２５の厚さを変えることにより、部品公差が組立公差に与える影響を排除していた。この場合、組み立てた電磁比例弁１００が図１１に示すような一定水準の流量制御特性を得ていない場合には、部品を分解して上スペーサ１２５の厚さを調整し、再組立てしなければならず、部品の組立調整に手間や時間がかかっていた。
【００１７】
そこで、本発明は、上記問題点を解決するためになされたものであり、部品の組立調整が容易な電磁比例弁を提供することを目的とする。
【００１８】
【課題を解決するための手段】
（１）本発明に係る電磁比例弁は、コイルへの印加電流に応じて吸引力を発生する固定鉄心と、固定鉄心に吸引される可動鉄心と、可動鉄心に固定される弁体と、弁体を収納する弁室が入口流路と出口流路と連通するように形成されたボディと、弁室に設けられて弁体が当接又は離間する弁座と、可動鉄心に固定されて弁体に弁閉方向の荷重を加える板バネと、固定鉄心を保持するとともに、ボディに嵌め込まれて板バネをボディとの間で狭持する保持部材とを備え、固定鉄心が発生する吸引力と板バネが弁体を弁座に押しつける力とのつり合いにより、弁体のストローク量を制御する電磁比例弁において、保持部材とボディとが螺合接続されるものであって、板バネとボディとの間に配設され、保持部材をボディにねじ込むときに、板バネを基準面に位置合わせしつつ、保持部材の任意の移動を許容する位置決め機構を有することを特徴とする。
【００１９】
（２）（１）に記載の発明において、板バネは、可動鉄心に固定される内周固定部と、内周固定部に対して外向きに接続されるものであって、曲線を描くように形成された複数の梁と、梁を介して内周固定部と接続するものであって、保持部材とボディとの間で狭持される複数の外周固定部とを有し、外周固定部が曲げ加工を施されて位置決め機構とされていることを特徴とする。
【００２０】
（３）（２）に記載の発明において、板バネは、内周固定部が中心部に切欠孔を有するＣ形に形成され、孔が、外周固定部と梁と内周固定部とにより形成される複数の長孔の１つと接続していることを特徴とする。
【００２１】
（４）（１）乃至（３）の何れか１つに記載の発明において、弁体は、熱可塑性を有する弾性体で形成されており、板バネは、内周固定部に弁体を保持する突起が内向きに設けられ、可動鉄心に対して溶接接合されることを特徴とする。
【００２２】
（５）（１）乃至（４）の何れか１つに記載の発明において、弁体が弁座に当接する面に鏡面加工を施されていることを特徴とする。
【００２３】
（６）（１）乃至（５）の何れか１つに記載の発明において、断面Ｕ字形に形成された環状の嵌装部材を有し、嵌装部材は、保持部材の内周面に固着され、固定鉄心が弁室に突き出るように圧入されていることを特徴とする。
【００２４】
（７）本発明に係る電磁比例弁の組立方法は、コイルへの印加電流に応じて吸引力を発生する固定鉄心と、固定鉄心に吸引される可動鉄心と、可動鉄心に固定される弁体と、弁体を収納する弁室が入口流路と出口流路とに連通するように形成されたボディと、弁室に設けられて弁体と当接又は離間する弁座と、可動鉄心に固定される内周固定部と、内周固定部に対して外向きに接続されるものであって、曲線を描くように形成された複数の梁と、梁を介して内周固定部と接続するものであって、梁との接続部分を基点として曲げ加工を施された外周固定部とからなる板バネと、固定鉄心を保持するとともに、ボディに螺合接続されて、板バネをボディとの間で狭持する保持部材と、を有する電磁比例弁を用いて、制御流体を入口流路に供給するとともに、コイルに所定量の電流を供給し、出口流路から排出される制御流体の流量を計測しながら、保持部材をボディにねじ込んで、保持部材とボディとの間で板バネの外周固定部を挟み込み、コイルへの印加電流に対応する流量が計測されたときに、保持部材をボディにねじ込むことを停止することを特徴とする。
【００２５】
上記構成を有する電磁比例弁では、保持部材をボディにねじ込むときに、板バネを基準面に位置合わせした状態で、保持部材をボディに対して任意の量だけねじ込むことが可能である。保持部材には、固定鉄心が保持される一方、板バネには、可動鉄心が固定されているため、保持部材のねじ込み量を調節すると、固定鉄心と可動鉄心との間の距離が変化する。固定鉄心と可動鉄心との間の距離が変化すると、吸引力特性が変化するため、保持部材のねじ込み量を調節すれば、開弁開始位置を自由に設定することが可能である。これにより、全ての電磁比例弁が一定水準の流量制御特性を有するように組み立てられ、同一の製品品質を得ることができる。
【００２６】
従って、本発明の電磁比例弁によれば、同一の製品品質を有する電磁比例弁を組み立てるために、部品を分解して再組立てする必要がないので、部品の組立調整を容易に行うことができる。
【００２７】
このとき、板バネの外周固定部について梁との接続部分を基点にして両端を折り曲げれば、保持部材をボディにねじ込んで板バネを狭持するときに、板バネの外周固定部が撓んでバネ力を発生し、位置決め機構の役割を果たすので、部品点数を増やすことなく、部品の組立精度を容易にすることができる。
【００２８】
また、板バネは、複数の外周固定部が分割して設けられ、外周固定部と梁と内周固定部との間に形成される長孔が一方に開口しており、さらに、長孔の１つが内周固定部の孔と接続しているので、ワイヤカットなどで板バネを簡単に形成することができる。
【００２９】
こうした板バネは、内周固定部が可動鉄心に溶接接合されるときに、突起が溶接の熱を内周固定部から伝達されて加熱し、弁体に食い込んで密接する。そのため、可動鉄心が作動する際に、弁体が可動鉄心から浮き上がって傾ぐことがなく、弁体のストローク量がコイルへの印加電流に応じて変位するとともに、板バネの支点位置が一定になる。従って、本発明の電磁比例弁によれば、作動特性を安定させることができる。
【００３０】
この点、弁体には、弁座と当接するシール部分に熱プレス転写により鏡面加工が施され、弁座と弁体との間の距離を安定させているので、従来の下スペーサを省いても、板バネの基準面を正確に設定することができる。
【００３１】
また、保持部材は、断面がＵ字形に形成された嵌装部材が固着され、その嵌装部材に対して固定鉄心を圧入することにより、保持部材と固定鉄心の高さ位置精度を出し、固定鉄心を保持している。嵌装部材は、固定鉄心が圧入されるときに、開口部が撓んでバネ力を発揮し、保持部材と固定鉄心との径方向での寸法公差を吸収する。よって、保持部材と固定鉄心との組立位置精度が得られ、部品加工精度を緩和することができる。
【００３２】
かかる電磁比例弁の部品組立を行う場合には、まず、制御流体を入口流路に供給し、コイルに所定の印加磁力を与え、固定鉄心に吸引力を発生させる。すると、可動鉄心が固定鉄心に吸引されて、弁体が弁座から分離し、制御流体が流量制御されて出口流路から排出される。
【００３３】
そこで、出口流路から排出される制御流体の流量を計測しながら、保持部材をボディにねじ込んでいく。保持部材をボディに所定量ねじ込むと、板バネの外周固定部が、保持部材とボディとの間で撓んで、板バネをボディに圧接させて基準面に位置合わせする一方、撓みによるバネ力によって保持部材の任意の移動を許容する。保持部材には、固定鉄心が保持される一方、板バネには、可動鉄心が固定されているため、固定鉄心と可動鉄心との間の距離は、保持部材のねじ込み量に応じて変化し、それに伴って吸引力特性が変化する。
【００３４】
電磁比例弁は、弁体が弁座から分離して制御する流量と、コイルへの印加電流による磁力とが比例関係にあり、弁体が弁座から分離し始める開弁開始位置は、吸引力特性によって変化する。そのため、電磁比例弁が、コイルへの印加電流による磁力に対応する流量を制御するまで、保持部材をボディにねじ込めば、固定鉄心と可動鉄心との間の距離が所定値に設定されて、特定の吸引力特性が得られ、さらには、開弁開始位置が一義的に定められる。これにより、全ての電磁比例弁は、一定水準の流量制御特性を有するように組み立てられ、同一の製品品質を得ることができる。
【００３５】
従って、本発明の電磁比例弁によれば、同一の製品品質を有する電磁比例弁を組み立てるために、部品寸法を測って組立調整したり、部品を分解してスペーサを交換した後に再組立てする必要がなく、部品の組立調整を容易に調節することができる。
【００３６】
【発明の実施の形態】
次に、本発明に係る電磁比例弁の実施の形態について図面を参照して説明する。図１及び図２は、電磁比例弁１の弁部拡大断面図である。図３は、電磁比例弁１の断面図である。
本実施の形態の電磁比例弁１も、従来技術の欄で説明した電磁比例弁１００と同様、半導体製造工程のプロセスガスを制御するために用いられ、コイル３２の電磁吸引力に比例してプランジャ（「可動鉄心」に相当するもの。）２５を吸引移動させ、弁シート（「弁体」に相当するもの。）１４を弁座８から分離させることにより、制御流体の流量制御を行うものである。
【００３７】
図３に示すように、ボディ２には、入口流路４と出口流路３とが形成され、その連通部分に弁孔７が設けられている。弁孔７は、ボディ２の上端面に形成された凹部６と連通している。凹部６には、弁座８が弁孔７の開口部の周りに弁シート１４側に突き出すように設けられ、さらに、弁座８の周りに段差９が設けられて、板バネ１０の基準面を設定している。
【００３８】
凹部６の開口部内周には、図１及び図２に示すように、雌ネジ１１が形成されている。雌ネジ１１に螺合する雄ネジ１２は、磁性材料を略円筒形状に形成した保持部材１３の外周面に形成されている。従って、ボディ２の段差９に板バネ１０を載置し、保持部材１３をボディ２の凹部６に螺合接続すれば、板バネ１０の外周固定部１８で板バネ１０を狭持することができる。
この点、板バネ１０は、中心部に形成された孔１９に対し、弁シート１４が固着されており、板バネ１０の復元力により、弁シート１４を弁座８に所定の取付荷重で押さえ付けるようになっている。
【００３９】
図４は、板バネ１０の平面図である。図５は、板バネ１０の側面図である。
板バネ１０は、円板状の形状をなし、内周固定部１６、梁１７、外周固定部１８とを備える。内周固定部１６はＣ形状に形成されて、中心部に孔１９が形成されている。内周固定部１６の内縁部分には、複数の突起２０が円周方向に等間隔で内向きに延設されている。一方、内周固定部１６の外縁部分には、５枚の梁１７が外向きの放射線状に延設されている。各梁１７は、コイル３２の非通電時においても弁シート１４を弁閉方向への荷重を発生可能なバネ特性を安定して発生するために、曲線でつながれたＳ字状の形状をなしている。各梁１７の外側端部には、外周固定部１８がそれぞれ接続している。
【００４０】
５枚の外周固定部１８は、円弧状の形状を有し、内周固定部１６と同心円状に等間隔で配設されている。従って、板バネ１０は、外周固定部１８が梁１７毎に分割して設けられることにより複数の長孔２１が形成され、さらにその長孔２１の１つが内周固定部１６の孔１９と接続している。また、外周固定部１８は、略中心位置において梁１７と接続し、その接続部分を基点として両端が折り曲げられて折曲部（「位置決め機構」に相当するもの。）２２が設けられ、バネ性を有している。尚、外周固定部１８の折曲部２２のバネ力は、弁シールに必要な板バネ歪以上に設定されている。これは、保持部材１３をボディ２に所定量以上ねじ込んだときに、保持部材１３のねじ込み量にかかわらず板バネ１０を一定の力で基準面に押しつけるためである。
【００４１】
図６は、プランジャ２５を固定された板バネ１０の平面図である。
板バネ１０は、内周固定部１６がプランジャ２５に溶接接合されている。プランジャ２５には、弁シート１４を収納するための弁体収納部２６が形成されており、その弁体収納部２６に弁シート１４が装着されたプランジャ２５に対して、板バネ１０の内周固定部１６をスポット溶接している（図中Ｐ１参照）。このとき、板バネ１０は、外周固定部１８の折曲部２２がプランジャ２５側に折り曲げられるように位置合わせされている（図１参照）。
【００４２】
一方、弁シート１４は、ＰＴＥＥ（四フッ化エチレン樹脂）などの熱可塑性を有する弾性体で形成され、板バネ１０の突起２０によりプランジャ２５の弁体収納部２６内に保持されている。弁シート１４は、弁座８と当接するシール部分２９に鏡面加工が施されている。
【００４３】
また、図３に示すように、電磁比例弁１では、固定鉄心３０を嵌装部材３１を介して保持部材１３に圧入して溶接又はろう付けすることにより、固定鉄心３０を保持している。嵌装部材３１は、環状をなし、断面がＵ字形に形成されている。そして、コイル３２が巻かれたボビン３３を嵌装部材３１及び保持部材１３に突き当てるように固定鉄心３０に対して挿入するとともに、ボビン３３等を覆うようにボンネット３４を保持部材１３に嵌め合わせ、固定鉄心３０をネジ３５でボンネット３４に取り付けて固定している。
【００４４】
この点、固定鉄心３０の下端部分は、嵌装部材３１から突出しており、保持部材１３と対向して弁室５内に存在している。嵌装部材３１は非磁性材料で形成されているのに対し、固定鉄心３０及び保持部材１３は磁性材料で形成されているため、固定鉄心３０と保持部材１３との間には、磁気漏洩空間３６が環状に形成されている。また、保持部材１３においては、ボディ２にねじ込まれた部分が、弁室５との側壁（の断面）として段差状に形成されている。さらに、固定鉄心３０の下端部分とプランジャ２５の中空部の位置関係は、固定鉄心３０の下端部分がプランジャ２５の中空部に接触することなく挿入される関係にある。また、保持部材１３の段差状の部分（弁室５の側壁）とリング状のプランジャ２５の突縁部２７との位置関係は、プランジャ２５が垂直上方向、垂直下方向の何れに移動しても、対向する関係にあるが、特に、図２に示すように、プランジャ２５が垂直上方向に移動しても、プランジャ２５の突縁部２７が保持部材１３の段差状の部分（弁室５の側壁）に接触することはない。
【００４５】
このような構成を有する電磁比例弁１では、ボディ２の入口流路４に対して制御流体が供給されるが、上述したように、常時は、板バネ１０の復元力により、所定の取付荷重で弁シート１４を弁座８に押しつけて、弁座８を閉じている。ここで、コイル３２に印加して固定鉄心３０や保持部材１３を磁化すると、図２に示すように、板バネ１０の復元力に抗して、プランジャ２５が固定鉄心３０や保持部材１３の磁力に吸引されて、固定鉄心３０や保持部材１３の間にある空隙を埋めるように、及び、固定鉄心３０と保持部材１３との間にある磁気漏洩空間３６を埋めるように、プランジャ２５が垂直上方向に無摺動で移動するので、弁シート１４が弁座８から分離し、弁座８を開くことができる。
【００４６】
この場合、電磁比例弁１は、プランジャ２５の自重と板バネ１０のバネ力の合成力に対して、コイル３２への印加電流による磁力に応じた吸引力がバランスする点まで開弁する。つまり、電磁比例弁１は、コイル３２への印加電流による磁力に比例した開度だけ開くように作動する。弁座８が開かれると、入口流路４に供給された制御流体は、入口流路４から弁座８を通過するときに、弁シート１４と弁座８との距離に応じた流量に制御された後、出口流路３から流出する。
【００４７】
尚、電磁比例弁１では、固定鉄心３０、嵌装部材３１、保持部材１３、ボディ２のそれぞれの間を溶接接合してシールすることにより、制御流体の漏れを防止している（図１及び図２に示すＰ２、Ｐ３、Ｐ４部分参照）。
【００４８】
以上詳細に説明したように、本実施の形態の電磁比例弁１では、保持部材１３をボディ２にねじ込むときに、板バネ１０の外周固定部１８が、撓んでバネ力を発生するため、板バネ１０をボディ２の段差９に圧接させて基準面に位置合わせした状態で、保持部材１３をボディ２に任意の量だけねじ込むことが可能である（図１、図２参照）。保持部材１３には、固定鉄心３０が保持される一方、板バネ１０には、プランジャ２５が固定されているため、保持部材１３のねじ込み量を調節すると、固定鉄心３０とプランジャ２５との間の距離が変化する。固定鉄心３０とプランジャ２５との間の距離が変化すると、図１０に示すように吸引力特性が変化するため、保持部材１３のねじ込み量を調節すれば、開弁開始位置Ｌ０を自由に設定することが可能である。これにより、全ての電磁比例弁１が図１１に示す一定水準の流量制御特性を有するように組み立てられ、同一の製品品質を得ることができる。
【００４９】
従って、本実施の形態の電磁比例弁１によれば、同一の製品品質を有する電磁比例弁１を組み立てるために、部品を分解して再組立てする必要がないので、部品の組立調整を容易に行うことができる。
【００５０】
このとき、保持部材１０をボディ２にねじ込んで板バネ１０を狭持するときに、板バネ１０の外周固定部１８の折曲部２２が撓んでバネ力を発生し、位置決め機構の役割を果たすので（図１、図２、図４、図５参照）、部品点数を増やすことなく、部品の組立精度を容易にすることができる。
【００５１】
また、板バネ１０は、５枚の外周固定部１８が分割して設けられ、外周固定部１８と梁１７と内周固定部１６との間に形成される長孔２１が一方に開口しており、さらに、長孔２１の１つが内周固定部１６の孔１９と接続しているので（図４参照）、ワイヤカットなどで板バネ１０を簡単に形成することができる。
【００５２】
こうした板バネ１０は、内周固定部１６が突起２０に対応する位置においてプランジャ２５にスポット溶接されるときに（図６参照）、突起２０がスポット溶接の熱を内周固定部１６から伝達されて加熱し、弁シート１４に食い込んで密接する（図１及び図２参照）。そのため、プランジャ２５が作動する際に、弁シート１４がプランジャ２５の弁体収納部２６から浮き上がって傾ぐことがなく、弁シート１４のストローク量が印加磁力に応じて変位するとともに、板バネ１０の支点位置が一定になる。従って、本実施の形態の電磁比例弁１によれば、作動特性を安定させることができる。
【００５３】
この点、弁シート１４には、弁座８と当接するシール部分２９に熱プレス転写により鏡面加工が施され（図６参照）、弁座８と弁シート１４との間の距離を安定させているので、従来の下スペーサ１２６（図９参照）を省いても、板バネ１０の基準面を正確に設定することができる。
【００５４】
また、磁性を有する保持部材１３は、断面がＵ字形に形成された非磁性材の嵌装部材３１が圧入固着され、その嵌装部材３１に対して磁性を有する固定鉄心３０を圧入することにより、保持部材１３と固定鉄心３０の高さ位置精度を出し、固定鉄心３０を保持している（図１及び図２参照）。嵌装部材３１は、固定鉄心３０が圧入されるときに、開口部が撓んでバネ力を発揮し、保持部材１３と固定鉄心３０との径方向での寸法公差を吸収する。よって、保持部材１３と固定鉄心３０との組立位置精度が得られ、部品加工精度を緩和することができる。
【００５５】
かかる電磁比例弁１が、図１１に示す流量制御特性を有するように部品組立を行う場合には、まず、制御流体を入口流路４に供給し、コイル３２に所定の印加磁力を与え、固定鉄心３０に吸引力を発生させる（図１、図３参照）。すると、プランジャ２５が固定鉄心３０に吸引されて、弁シート１４が弁座８から分離し、制御流体が流量制御されて出口流路３から排出される（図２参照）。
【００５６】
そこで、出口流路３から排出される制御流体の流量を計測しながら、保持部材１３をボディ２にねじ込んでいく。保持部材１３をボディ２に所定量ねじ込むと、板バネ１０の外周固定部１８が、保持部材１３とボディ２との間で撓んで、板バネ１０をボディ２の段差９に圧接させて基準面に位置合わせする一方、撓みによるバネ力によって保持部材１３の任意の移動を許容する（図２参照）。保持部材１３には、固定鉄心１３が保持される一方、板バネ１０には、プランジャ２５が固定されるため、固定鉄心３０とプランジャ２５との間の距離は、保持部材１３をボディ２にねじ込む量に応じて変化し、それに伴って吸引力特性が変化する（図１０参照）。
【００５７】
電磁比例弁１は、図１１に示すように、弁シート１４が弁座８から分離して制御する流量と、コイル３２への印加電流による磁力とが比例関係にあり、弁シート１４が弁座８から分離し始める開弁開始位置Ｌ０は、図１０に示す吸引力特性によって変化する。そのため、電磁比例弁１が、コイル３２への印加電流による磁力に対応する流量（例えば、図１１の流量制御特性を得る場合には、３００ＡＴの印加磁力に対して１５０％流量）を制御するまで、保持部材１３をボディ２の凹部６にねじ込めば、固定鉄心３０とプランジャ２５との間の距離が所定値に設定され、図１０のバネ線図Ｋに示す吸引力特性が得られ、さらには、開弁開始位置Ｌ０が一義的に定められる。これにより、全ての電磁比例弁１は、図１１に示す一定水準の流量制御特性を有するように組み立てられ、同一の製品品質を得ることができる。
【００５８】
従って、本実施の形態の電磁比例弁１によれば、同一の製品品質を有する電磁比例弁１を組み立てるために、部品寸法を測って組立調整したり、部品を分解してスペーサを交換した後に再組立てする必要がなく、部品の組立調整を容易に調節することができる。
【００５９】
以上、本発明の実施の形態について説明したが、本発明は、上記実施の形態に限定されることなく、色々な応用が可能である。
【００６０】
（１）例えば、上記実施の形態では、板バネ１０の外周固定部１８を折り曲げて折曲部２２を設け、位置決め機構とした。それに対して、従来の板バネ（図８参照）のように板バネの外周固定部をリング状に形成し、リングワッシャなどの別部材を用いて位置決め機構としてもよい。
【００６１】
（２）例えば、上記実施の形態では、嵌装部材３１が開口部を上方に向けて保持部材１３と固定鉄心３０との間に配設されている。それに対して、開口部を下方に向けて嵌装部材３１を保持部材１３と固定鉄心３０との間に配設してもよい。また、嵌装部材の開口部が形成された端面と反対側の端面を、断面円弧型に形成することにより、より強いバネ力を持たせるようにしてもよい。
【００６２】
【発明の効果】
本発明に係る電磁比例弁は、コイルへの印加電流に応じて吸引力を発生する固定鉄心と、固定鉄心に吸引される可動鉄心と、可動鉄心に固定される弁体と、弁体を収納する弁室が入口流路と出口流路と連通するように形成されたボディと、弁室に設けられて弁体が当接又は離間する弁座と、可動鉄心に固定されて弁体に弁閉方向の荷重を加える板バネと、固定鉄心を保持するとともに、ボディに嵌め込まれて板バネをボディとの間で狭持する保持部材とを備え、固定鉄心が発生する吸引力と板バネが弁体を弁座に押しつける力とのつり合いにより、弁体のストローク量を制御する電磁比例弁において、保持部材とボディとが螺合接続されるものであって、板バネとボディとの間に配設され、保持部材をボディにねじ込むときに、板バネを基準面に位置合わせしつつ、保持部材の任意の移動を許容する位置決め機構を有しているので、部品の組立調整を容易に行うことができる。
【００６３】
また、本発明に係る電磁比例弁の組立方法によれば、コイルへの印加電流に応じて吸引力を発生する固定鉄心と、固定鉄心に吸引される可動鉄心と、可動鉄心に固定される弁体と、弁体を収納する弁室が入口流路と出口流路とに連通するように形成されたボディと、弁室に設けられて弁体と当接又は離間する弁座と、可動鉄心に固定される内周固定部と、内周固定部に対して外向きに接続されるものであって、曲線を描くように形成された複数の梁と、梁を介して内周固定部と接続するものであって、梁との接続部分を基点として曲げ加工を施された外周固定部とからなる板バネと、固定鉄心を保持するとともに、ボディに螺合接続されて、板バネをボディとの間で狭持する保持部材と、を有する電磁比例弁を用いて、制御流体を入口流路に供給するとともに、コイルに所定量の電流を供給し、出口流路から排出される制御流体の流量を計測しながら、保持部材をボディにねじ込んで、保持部材とボディとの間で板バネの外周固定部を挟み込み、コイルへの印加電流に対応する流量が計測されたときに、保持部材をボディにねじ込むことを停止するので、部品の組立調整を容易に行うことができる。
【図面の簡単な説明】
【図１】本発明の実施の形態に係り、電磁比例弁が閉弁している状態の弁部拡大断面図である。
【図２】同じく、電磁比例弁が開弁している状態の弁部拡大断面図である。
【図３】同じく、電磁比例弁の断面図である。
【図４】同じく、板バネの平面図である。
【図５】同じく、板バネの側面図である。
【図６】同じく、プランジャに固定された板バネの平面図である。
【図７】従来の電磁比例弁の断面図である。
【図８】従来の電磁比例弁で使用される板バネの一例を示す正面図である。
【図９】従来の電磁比例弁の弁部拡大断面図である。
【図１０】電磁比例弁の吸引力特性を示す図である。
【図１１】電磁比例弁の流量制御特性を示す図である。
【符号の説明】
１電磁比例弁
２ボディ
３入口流路
４出口流路
５弁室
８弁座
１０板バネ
１３保持部材
３０固定鉄心
３１嵌装部材
１６内周固定部
１７梁
１８外周固定部
１９孔
２０突起
３２コイル
２５プランジャ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electromagnetic proportional valve that controls a stroke amount of a valve body by operating a plunger without sliding by a suction force generated by a fixed iron core.
[0002]
[Prior art]
Conventionally, in a semiconductor manufacturing process, fine processing has progressed, and a control fluid such as process gas is precisely controlled by an electromagnetic proportional valve.
Some electromagnetic proportional valves employ a plunger system, for example. A plunger-type solenoid valve has a fixed iron core fixed to a coil bobbin around which a coil is wound, and a rod-like plunger is slidably inserted coaxially with the fixed iron core. It contacts or separates from the seat. In such a plunger type electromagnetic valve, the rod-shaped plunger slides in the coil bobbin in proportion to the current applied to the coil, and the valve body is separated from the valve seat to control the flow rate of the control fluid. At this time, the rod-shaped plunger has an advantage that the stroke amount of the valve body can be adjusted with a small amount of energization because the attractive force acts on the surface facing the fixed iron core and the outer peripheral surface inserted into the coil bobbin.
[0003]
However, in the plunger method, particles are generated when the rod-shaped plunger slides, which adversely affects the product quality, and because the rod-shaped plunger is inserted into the coil, the overall height of the device is high and the device size is large. There are drawbacks.
[0004]
In order to compensate for these disadvantages, an electromagnetic proportional valve that employs a flapper system has been proposed. The flapper system controls the stroke of the valve body by operating the plunger without sliding in proportion to the magnetic force generated by the current applied to the coil. I have to.
[0005]
FIG. 7 is a cross-sectional view of an electromagnetic proportional valve 100 that employs a flapper system.
In the electromagnetic proportional valve 100, an inlet channel 103 and an outlet channel 102 are formed in a body 101, and a valve chamber 104 is provided in a communicating portion thereof. In the valve chamber 104, a valve seat 105 is provided around an opening communicating with the outlet channel 102. A holding member 106 is fitted into the body 101, and a plate spring 107 is held between the body 101 and the holding member 106. A valve seat 109 is attached to the leaf spring 107 via a valve seat holding plate 110 in a hole 108 (see FIG. 8) provided in the center, and the valve seat 109 is attached to the valve seat 105 by an attachment load of the leaf spring 107. Is pressed against.
[0006]
As shown in the front view of FIG. 8, in the leaf spring 107, an inner periphery fixing portion 111 and an outer periphery fixing portion 112 are formed concentrically around the hole 108 in order to make elastic deformation in the thickness direction smooth. In addition, each of the four beams 113 is formed in a substantially S shape between the inner periphery fixing portion 111 and the outer periphery fixing portion 112.
[0007]
As shown in the enlarged sectional view of the valve portion shown in FIG. 9, the leaf spring 107 is in a state where the inner peripheral fixing portion 111 is overlapped with the plunger 115 on which the valve seat 109 is mounted and the valve seat pressing plate 110. The plunger 115 is welded and fixed to the plunger 115 (see P11 in the figure). Thus, the leaf spring 107 is integrated with the valve seat 109 and the plunger 115. Further, the outer peripheral fixing portion 112 of the leaf spring 107 is sandwiched between the upper spacer 125 and the lower spacer 126, thereby supporting the leaf spring 107 in alignment with the plunger 115, the valve seat 105, and the like. .
[0008]
A fitting member 117 made of a non-magnetic material is fixed to the holding member 106 by welding to hold the fixed iron core 118. Accordingly, when a current is supplied to the coil 119, the fixed iron core 118 and the holding member 106 are excited, and the plunger 115 is attracted against the restoring force of the leaf spring 107.
[0009]
In the electromagnetic proportional valve 100 of FIG. 7, when a predetermined current is supplied to the coil 119 and a magnetic force is applied, as shown in a spring diagram K of FIG. The operation is performed in that the attraction force generated by the fixed iron core 118 is balanced with the force according to the current supplied to the coil 119. Therefore, for example, assuming that the leaf spring 107 has a predetermined spring constant, when an applied magnetic force of 150 AT is applied to the coil 119, the force applied to the plunger 115 and the F1 point are balanced, and this point is balanced with no pressure of the control fluid. The valve opening start position is set to the position of the valve displacement L0. Further, for example, when the applied magnetic force is increased to 300 AT, the force applied to the plunger 115 is balanced at the point F2, the valve is in the L1 position, and the distance from L0 to L1 is the valve movement distance for opening the valve. The electromagnetic proportional valve 100 in FIG. 7 changes the attractive force characteristic shown in FIG. 10 by adjusting the distance between the plunger 115 and the fixed iron core 118 by the amount by which the holding member 106 is fitted into the body 101. In addition, the valve opening start position L0 can be arbitrarily set.
[0010]
As described above, the electromagnetic proportional valve 100 shown in FIG. 7 operates with the valve being displaced in proportion to the magnetic force generated by the current applied to the coil 119. The flow rate of the control fluid flowing through the valve with respect to the magnetic force due to the applied current at that time becomes the flow rate control characteristic shown in FIG. 11 with respect to the attractive force characteristic shown in the spring diagram K of FIG. That is, this graph is a graph when the valve opening is set to start when an applied magnetic force of 100 to 150 AT is applied to the electromagnetic proportional valve 100, and it is measured in advance that the control fluid flows with such characteristics. The applied magnetic force to obtain a predetermined flow rate can be obtained and controlled, and the flow rate of the control fluid flowing through the flow path is measured to adjust the applied magnetic force so that the predetermined flow rate is always obtained. It can also be controlled.
[0011]
Therefore, the electromagnetic proportional valve 100 of FIG. 7 is supplied with the control fluid to the inlet flow path 103 of the body 101, but as shown in FIG. 11, until the applied magnetic force of 100 to 150AT is applied to the coil 119, The valve seat 109 is pressed against the valve seat 105 with a predetermined mounting load by the restoring force of the leaf spring 107 to close the valve seat 105.
[0012]
Here, when an applied magnetic force of 300 AT is applied to the coil 119, the plunger 115 is attracted by the magnetic force of the fixed iron core 118 and the holding member 106 against the restoring force of the leaf spring 107, and moves vertically upward. The seat 109 separates from the valve seat 105 and opens the valve seat 105. At this time, the electromagnetic proportional valve 100 supplies the control fluid from the inlet channel 103 to the outlet channel 102 at a flow rate of 150% (see, for example, Patent Document 1).
[Patent Document 1]
Japanese Patent Laid-Open No. 2002-71045 (pages 4 to 5, FIGS. 1 and 2).
[0013]
[Problems to be solved by the invention]
However, the conventional electromagnetic proportional valve 100 shown in FIG. 7 has a problem that it is difficult to assemble and adjust components so as to obtain a desired flow rate control characteristic.
[0014]
That is, in the electromagnetic proportional valve 100, the distance between the plunger 115 and the fixed iron core 118 is required to be set within several tens of μm, and the flow control is performed by adjusting the operation of the plunger 115 with an accuracy of several μm. ing. Under these conditions, in order for all of the assembled electromagnetic proportional valves 100 to have a constant flow control characteristic, it is necessary to obtain a constant attractive force characteristic. The suction force characteristic changes depending on the distance between the plunger 115 and the fixed iron core 118. That is, if the distance between the plunger 115 and the fixed iron core 118 varies, as shown in FIG. 10, the spring diagram K varies in the horizontal direction in the figure without changing the inclination (the spring constant of the leaf spring 107). (See K1 and K2 in the figure), the valve opening start position L0 is shifted. When the valve opening start position L0 deviates, the flow rate control characteristics shown in FIG. 11 also vary in the left-right direction in the figure, and the product quality is not constant. Therefore, it is necessary to assemble the electromagnetic proportional valve 100 so as to precisely set the distance between the plunger 115 and the fixed iron core 118 and determine the valve opening start position L0.
[0015]
In this regard, in the electromagnetic proportional valve 100, as shown in FIG. 9, the lower spacer 126, the leaf spring 107, and the upper spacer 125 are stacked on the body 101, and the holding member 106 is fitted into the body 101. The accuracy of the distance between the fixed iron core 118 and the fixed iron core 118 is absolutely obtained. Therefore, component tolerances such as the body 101, the valve seat 105, the holding member 106, and the leaf spring 107 directly affect the distance between the plunger 115 and the fixed iron core 118, thereby causing variations in product quality. On the other hand, it is conceivable to reduce the assembly tolerance by improving the dimensional accuracy of the parts. However, the allowable part tolerance is less than several μm because the plunger 115 operates with a minute amount of several μm. Just improving the dimensional accuracy of the parts is not enough.
[0016]
Therefore, in the electromagnetic proportional valve 100, the influence of the component tolerance on the assembly tolerance is eliminated by changing the thickness of the upper spacer 125 according to the component tolerance of the body 101, the holding member 106, and the like. In this case, if the assembled solenoid proportional valve 100 does not obtain a certain level of flow control characteristics as shown in FIG. 11, the parts must be disassembled to adjust the thickness of the upper spacer 125 and reassembled. In other words, it took time and effort to assemble and adjust the parts.
[0017]
Accordingly, the present invention has been made to solve the above-described problems, and an object of the present invention is to provide an electromagnetic proportional valve in which assembly adjustment of parts is easy.
[0018]
[Means for Solving the Problems]
(1) An electromagnetic proportional valve according to the present invention includes a fixed iron core that generates a suction force in response to an electric current applied to a coil, a movable iron core that is attracted to the fixed iron core, a valve body that is fixed to the movable iron core, A body formed so that a valve chamber for housing the body communicates with the inlet channel and the outlet channel, a valve seat provided in the valve chamber with which the valve body contacts or separates, and a valve fixed to the movable iron core A plate spring that applies a load in the valve closing direction to the body, and a holding member that holds the fixed iron core and that is fitted into the body and holds the plate spring between the body and the suction force generated by the fixed iron core; In an electromagnetic proportional valve that controls the stroke amount of the valve body by balancing with the force with which the leaf spring presses the valve body against the valve seat, the holding member and the body are screwed together. When the holding member is screwed into the body, the leaf spring While being aligned to the reference plane, and having a positioning mechanism that allows any movement of the holding member.
[0019]
(2) In the invention described in (1), the leaf spring is connected to the inner peripheral fixed portion fixed to the movable iron core and the inner peripheral fixed portion outwardly, and draws a curve. A plurality of beams formed on the inner periphery fixing portion, and a plurality of outer periphery fixing portions sandwiched between the holding member and the body. Is subjected to bending processing to form a positioning mechanism.
[0020]
(3) In the invention described in (2), the leaf spring is formed in a C shape in which the inner peripheral fixing portion has a notch hole in the center, and the hole is formed by the outer peripheral fixing portion, the beam, and the inner peripheral fixing portion. It is connected to one of a plurality of long holes.
[0021]
(4) In the invention according to any one of (1) to (3), the valve body is formed of an elastic body having thermoplasticity, and the leaf spring holds the valve body on the inner peripheral fixed portion. The protrusion to be provided is provided inward and welded to the movable iron core.
[0022]
(5) In the invention according to any one of (1) to (4), the surface of the valve body that contacts the valve seat is mirror-finished.
[0023]
(6) In the invention according to any one of (1) to (5), the fitting member has an annular fitting member formed in a U-shaped cross section, and the fitting member is fixed to the inner peripheral surface of the holding member. The fixed iron core is press-fitted so as to protrude into the valve chamber.
[0024]
(7) A method for assembling an electromagnetic proportional valve according to the present invention includes a fixed iron core that generates an attractive force according to an electric current applied to a coil, a movable iron core that is attracted to the fixed iron core, and a valve body that is fixed to the movable iron core. And a body formed such that a valve chamber for accommodating the valve body communicates with the inlet flow path and the outlet flow path, a valve seat provided in the valve chamber and contacting or separating from the valve body, and a movable iron core A fixed inner peripheral fixed part, connected to the inner peripheral fixed part outward, and connected to the inner peripheral fixed part via a plurality of beams formed to draw a curve. A leaf spring composed of an outer peripheral fixed portion bent from the connection portion with the beam, and a fixed iron core, and is screwed to the body to connect the leaf spring to the body. And a control member having a holding member sandwiched between the control fluid and the inlet fluid. In addition, while supplying a predetermined amount of current to the coil and measuring the flow rate of the control fluid discharged from the outlet channel, the holding member is screwed into the body, and the outer peripheral fixing portion of the leaf spring between the holding member and the body When the flow rate corresponding to the current applied to the coil is measured, the screwing of the holding member into the body is stopped.
[0025]
In the electromagnetic proportional valve having the above configuration, when the holding member is screwed into the body, the holding member can be screwed into the body by an arbitrary amount in a state where the leaf spring is aligned with the reference surface. Since the fixed iron core is held by the holding member, and the movable iron core is fixed to the leaf spring, adjusting the screwing amount of the holding member changes the distance between the fixed iron core and the movable iron core. When the distance between the fixed iron core and the movable iron core changes, the suction force characteristics change. Therefore, the valve opening start position can be freely set by adjusting the screwing amount of the holding member. Thereby, all the electromagnetic proportional valves are assembled so as to have a certain level of flow rate control characteristics, and the same product quality can be obtained.
[0026]
Therefore, according to the electromagnetic proportional valve of the present invention, it is not necessary to disassemble and reassemble the parts in order to assemble the electromagnetic proportional valves having the same product quality, so that the assembly adjustment of the parts can be easily performed. .
[0027]
At this time, if both ends of the outer periphery fixing portion of the leaf spring are bent from the connection portion with the beam, the outer periphery fixing portion of the leaf spring is bent when the holding member is screwed into the body and the leaf spring is clamped. Since the spring force is generated and functions as a positioning mechanism, the assembly accuracy of the components can be facilitated without increasing the number of components.
[0028]
The leaf spring is provided with a plurality of outer peripheral fixed portions divided, and a long hole formed between the outer peripheral fixed portion, the beam, and the inner peripheral fixed portion is opened in one side. Since one is connected to the hole of the inner periphery fixing portion, the leaf spring can be easily formed by wire cutting or the like.
[0029]
In such a leaf spring, when the inner peripheral fixed portion is welded and joined to the movable iron core, the projections are heated by transmitting the heat of welding from the inner peripheral fixed portion, and are brought into close contact with the valve body. For this reason, when the movable iron core is operated, the valve element does not lift up and tilt from the movable iron core, the stroke amount of the valve element is displaced according to the current applied to the coil, and the fulcrum position of the leaf spring becomes constant. . Therefore, according to the electromagnetic proportional valve of the present invention, the operating characteristics can be stabilized.
[0030]
In this respect, the valve body is mirror-finished by heat press transfer on the seal part that contacts the valve seat, stabilizing the distance between the valve seat and the valve body, so the conventional lower spacer is omitted. In addition, the reference plane of the leaf spring can be set accurately.
[0031]
In addition, the holding member is fixed to a fitting member having a U-shaped cross section, and the fixed core is press-fitted into the fitting member so that the height position accuracy of the holding member and the fixed core is obtained and fixed. Holding the iron core. When the fixed iron core is press-fitted, the fitting member exhibits a spring force by bending the opening, and absorbs the dimensional tolerance in the radial direction between the holding member and the fixed iron core. Therefore, the assembly position accuracy of the holding member and the fixed iron core can be obtained, and the component processing accuracy can be relaxed.
[0032]
When assembling parts of such an electromagnetic proportional valve, first, a control fluid is supplied to the inlet flow path, a predetermined applied magnetic force is applied to the coil, and an attractive force is generated in the fixed iron core. Then, the movable iron core is sucked into the fixed iron core, the valve body is separated from the valve seat, the control fluid is controlled in flow rate, and is discharged from the outlet flow path.
[0033]
Therefore, the holding member is screwed into the body while measuring the flow rate of the control fluid discharged from the outlet channel. When the holding member is screwed into the body by a predetermined amount, the outer peripheral fixing portion of the leaf spring is bent between the holding member and the body, and the leaf spring is pressed against the body and aligned with the reference surface. An arbitrary movement of the holding member is allowed. While the fixed iron core is held by the holding member, the movable iron core is fixed to the leaf spring, so the distance between the fixed iron core and the movable iron core changes according to the screwing amount of the holding member, Along with this, the suction force characteristics change.
[0034]
In an electromagnetic proportional valve, the flow rate that the valve body separates from the valve seat and the magnetic force due to the current applied to the coil are in a proportional relationship, and the valve opening start position where the valve body begins to separate from the valve seat is the suction force. Varies with characteristics. Therefore, if the holding member is screwed into the body until the electromagnetic proportional valve controls the flow rate corresponding to the magnetic force due to the current applied to the coil, the distance between the fixed iron core and the movable iron core is set to a predetermined value, A specific suction force characteristic is obtained, and furthermore, the valve opening start position is uniquely determined. Thereby, all the electromagnetic proportional valves are assembled so as to have a certain level of flow control characteristics, and the same product quality can be obtained.
[0035]
Therefore, according to the electromagnetic proportional valve of the present invention, in order to assemble an electromagnetic proportional valve having the same product quality, it is necessary to measure and assemble parts by adjusting the dimensions of the parts or to reassemble after disassembling the parts and replacing the spacers. The assembly adjustment of parts can be easily adjusted.
[0036]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of an electromagnetic proportional valve according to the present invention will be described with reference to the drawings. 1 and 2 are enlarged cross-sectional views of the valve portion of the electromagnetic proportional valve 1. FIG. 3 is a cross-sectional view of the electromagnetic proportional valve 1.
The electromagnetic proportional valve 1 according to the present embodiment is also used to control the process gas in the semiconductor manufacturing process, as in the case of the electromagnetic proportional valve 100 described in the section of the prior art, and the plunger is proportional to the electromagnetic attractive force of the coil 32. (Corresponding to “movable iron core”) 25 is sucked and moved, and the valve seat (corresponding to “valve element”) 14 is separated from the valve seat 8 to control the flow rate of the control fluid. is there.
[0037]
As shown in FIG. 3, the body 2 is formed with an inlet channel 4 and an outlet channel 3, and a valve hole 7 is provided at a communicating portion thereof. The valve hole 7 communicates with a recess 6 formed on the upper end surface of the body 2. In the recess 6, the valve seat 8 is provided so as to protrude toward the valve seat 14 around the opening of the valve hole 7, and a step 9 is provided around the valve seat 8, so that the reference surface of the leaf spring 10 is provided. Is set.
[0038]
A female screw 11 is formed on the inner periphery of the opening of the recess 6 as shown in FIGS. The male screw 12 that is screwed into the female screw 11 is formed on the outer peripheral surface of a holding member 13 in which a magnetic material is formed in a substantially cylindrical shape. Therefore, if the leaf spring 10 is placed on the step 9 of the body 2 and the holding member 13 is screwed and connected to the recess 6 of the body 2, the leaf spring 10 can be held by the outer peripheral fixing portion 18 of the leaf spring 10. it can.
In this respect, the leaf spring 10 has a valve seat 14 fixed to a hole 19 formed in the center thereof, and the restoring force of the leaf spring 10 holds the valve seat 14 against the valve seat 8 with a predetermined mounting load. It is supposed to be attached.
[0039]
FIG. 4 is a plan view of the leaf spring 10. FIG. 5 is a side view of the leaf spring 10.
The leaf spring 10 has a disk shape and includes an inner peripheral fixing portion 16, a beam 17, and an outer peripheral fixing portion 18. The inner periphery fixing part 16 is formed in a C shape, and a hole 19 is formed in the center part. A plurality of protrusions 20 extend inwardly at equal intervals in the circumferential direction on the inner edge portion of the inner peripheral fixing portion 16. On the other hand, five beams 17 are extended radially outward at the outer edge portion of the inner peripheral fixed portion 16. Each beam 17 has an S-shape connected by a curve in order to stably generate a spring characteristic capable of generating a load in the valve closing direction even when the coil 32 is not energized. Yes. An outer peripheral fixing portion 18 is connected to the outer end portion of each beam 17.
[0040]
The five outer peripheral fixing portions 18 have an arc shape, and are arranged concentrically with the inner peripheral fixing portion 16 at equal intervals. Accordingly, the leaf spring 10 has a plurality of long holes 21 formed by dividing the outer peripheral fixing portion 18 for each beam 17, and one of the long holes 21 is connected to the hole 19 of the inner peripheral fixing portion 16. is doing. Further, the outer peripheral fixing portion 18 is connected to the beam 17 at a substantially central position, and both ends thereof are bent with the connection portion as a base point to be provided with a bent portion (corresponding to a “positioning mechanism”) 22, which has a spring property. have. Note that the spring force of the bent portion 22 of the outer peripheral fixing portion 18 is set to be equal to or greater than the leaf spring strain necessary for valve sealing. This is because when the holding member 13 is screwed into the body 2 by a predetermined amount or more, the leaf spring 10 is pressed against the reference surface with a constant force regardless of the screwing amount of the holding member 13.
[0041]
FIG. 6 is a plan view of the leaf spring 10 to which the plunger 25 is fixed.
The leaf spring 10 has an inner peripheral fixed portion 16 welded to the plunger 25. The plunger 25 is formed with a valve body housing portion 26 for housing the valve seat 14, and the inner periphery of the leaf spring 10 with respect to the plunger 25 having the valve seat 14 mounted on the valve body housing portion 26. The fixed portion 16 is spot welded (see P1 in the figure). At this time, the leaf spring 10 is aligned so that the bent portion 22 of the outer periphery fixing portion 18 is bent toward the plunger 25 (see FIG. 1).
[0042]
On the other hand, the valve seat 14 is formed of an elastic body having thermoplasticity such as PTEE (tetrafluoroethylene resin), and is held in the valve body housing portion 26 of the plunger 25 by the protrusion 20 of the leaf spring 10. The valve seat 14 is mirror-finished on a seal portion 29 that comes into contact with the valve seat 8.
[0043]
As shown in FIG. 3, in the electromagnetic proportional valve 1, the fixed iron core 30 is held by press-fitting the fixed iron core 30 into the holding member 13 via the fitting member 31 and welding or brazing. The fitting member 31 has an annular shape and has a U-shaped cross section. The bobbin 33 around which the coil 32 is wound is inserted into the fixed iron core 30 so as to abut against the fitting member 31 and the holding member 13, and the bonnet 34 is fitted to the holding member 13 so as to cover the bobbin 33 and the like. The fixed iron core 30 is fixed to the bonnet 34 with screws 35.
[0044]
In this regard, the lower end portion of the fixed iron core 30 protrudes from the fitting member 31 and is present in the valve chamber 5 so as to face the holding member 13. The fitting member 31 is made of a nonmagnetic material, whereas the fixed iron core 30 and the holding member 13 are made of a magnetic material. Therefore, a magnetic leakage space is formed between the fixed iron core 30 and the holding member 13. 36 is formed in an annular shape. Further, in the holding member 13, a portion screwed into the body 2 is formed in a step shape as a side wall (cross section) with the valve chamber 5. Furthermore, the positional relationship between the lower end portion of the fixed iron core 30 and the hollow portion of the plunger 25 is such that the lower end portion of the fixed iron core 30 is inserted without contacting the hollow portion of the plunger 25. Further, the positional relationship between the stepped portion of the holding member 13 (side wall of the valve chamber 5) and the protruding edge portion 27 of the ring-shaped plunger 25 is such that the plunger 25 moves in either the vertical upward direction or the vertical downward direction. In particular, as shown in FIG. 2, even when the plunger 25 moves vertically upward, the protruding edge portion 27 of the plunger 25 is a stepped portion (valve chamber 5) of the holding member 13. Side wall).
[0045]
In the electromagnetic proportional valve 1 having such a configuration, the control fluid is supplied to the inlet flow path 4 of the body 2. However, as described above, a predetermined mounting load is always obtained by the restoring force of the leaf spring 10. Thus, the valve seat 14 is pressed against the valve seat 8 to close the valve seat 8. Here, when the fixed iron core 30 and the holding member 13 are magnetized by being applied to the coil 32, the plunger 25 resists the restoring force of the leaf spring 10 and the magnetic force of the fixed iron core 30 and the holding member 13 as shown in FIG. So as to fill the gap between the fixed core 30 and the holding member 13 and so as to fill the magnetic leakage space 36 between the fixed core 30 and the holding member 13. Since it moves without sliding in the direction, the valve seat 14 can be separated from the valve seat 8 and the valve seat 8 can be opened.
[0046]
In this case, the electromagnetic proportional valve 1 opens to a point where the attractive force according to the magnetic force generated by the current applied to the coil 32 is balanced against the combined force of the weight of the plunger 25 and the spring force of the leaf spring 10. That is, the electromagnetic proportional valve 1 operates so as to open by an opening degree proportional to the magnetic force generated by the current applied to the coil 32. When the valve seat 8 is opened, the control fluid supplied to the inlet passage 4 is controlled to have a flow rate according to the distance between the valve seat 14 and the valve seat 8 when passing through the valve seat 8 from the inlet passage 4. Then, it flows out from the outlet channel 3.
[0047]
In the electromagnetic proportional valve 1, leakage of the control fluid is prevented by welding and sealing the fixed iron core 30, the fitting member 31, the holding member 13, and the body 2 (see FIG. 1 and FIG. 1). (Refer P2, P3, and P4 portions shown in FIG. 2).
[0048]
As described in detail above, in the electromagnetic proportional valve 1 according to the present embodiment, when the holding member 13 is screwed into the body 2, the outer peripheral fixing portion 18 of the leaf spring 10 is bent to generate a spring force. The holding member 13 can be screwed into the body 2 by an arbitrary amount in a state where the spring 10 is brought into pressure contact with the step 9 of the body 2 and aligned with the reference plane (see FIGS. 1 and 2). Since the fixed iron core 30 is held by the holding member 13, and the plunger 25 is fixed to the leaf spring 10, when the screwing amount of the holding member 13 is adjusted, the distance between the fixed iron core 30 and the plunger 25 is adjusted. The distance changes. When the distance between the fixed iron core 30 and the plunger 25 changes, the suction force characteristic changes as shown in FIG. 10, and therefore the valve opening start position L0 can be freely set by adjusting the screwing amount of the holding member 13. It is possible. Thereby, all the solenoid proportional valves 1 are assembled so as to have a certain level of flow rate control characteristics shown in FIG. 11, and the same product quality can be obtained.
[0049]
Therefore, according to the electromagnetic proportional valve 1 of the present embodiment, it is not necessary to disassemble and reassemble parts in order to assemble the electromagnetic proportional valve 1 having the same product quality. It can be carried out.
[0050]
At this time, when the holding member 10 is screwed into the body 2 to hold the leaf spring 10, the bent portion 22 of the outer peripheral fixing portion 18 of the leaf spring 10 is bent to generate a spring force, which serves as a positioning mechanism. Therefore, the assembly accuracy of the components can be facilitated without increasing the number of components (see FIGS. 1, 2, 4, and 5).
[0051]
Further, the leaf spring 10 is provided by dividing the five outer peripheral fixing portions 18, and a long hole 21 formed between the outer peripheral fixing portion 18, the beam 17, and the inner peripheral fixing portion 16 opens to one side. Furthermore, since one of the long holes 21 is connected to the hole 19 of the inner periphery fixing portion 16 (see FIG. 4), the leaf spring 10 can be easily formed by wire cutting or the like.
[0052]
The leaf spring 10 is configured such that when the inner periphery fixing portion 16 is spot welded to the plunger 25 at a position corresponding to the protrusion 20 (see FIG. 6), the heat of the spot welding is transmitted from the inner periphery fixing portion 16. Heated and bite into and close to the valve seat 14 (see FIGS. 1 and 2). Therefore, when the plunger 25 is actuated, the valve seat 14 is not lifted and tilted from the valve body housing portion 26 of the plunger 25, the stroke amount of the valve seat 14 is displaced according to the applied magnetic force, and the leaf spring 10 The fulcrum position is constant. Therefore, according to the electromagnetic proportional valve 1 of the present embodiment, the operation characteristics can be stabilized.
[0053]
In this respect, the valve seat 14 is mirror-finished by heat press transfer on the seal portion 29 that is in contact with the valve seat 8 (see FIG. 6), and the distance between the valve seat 8 and the valve seat 14 is stabilized. Therefore, even if the conventional lower spacer 126 (see FIG. 9) is omitted, the reference surface of the leaf spring 10 can be accurately set.
[0054]
In addition, the holding member 13 having magnetism is formed by press-fitting and fixing a non-magnetic fitting member 31 having a U-shaped cross section, and press-fitting the magnetic fixed iron core 30 to the fitting member 31. The height position accuracy of the holding member 13 and the fixed iron core 30 is obtained, and the fixed iron core 30 is held (see FIGS. 1 and 2). When the fixed iron core 30 is press-fitted, the fitting member 31 deflects the opening and exerts a spring force, and absorbs the dimensional tolerance in the radial direction between the holding member 13 and the fixed iron core 30. Therefore, the assembly position accuracy of the holding member 13 and the fixed iron core 30 is obtained, and the component processing accuracy can be relaxed.
[0055]
When the electromagnetic proportional valve 1 assembles components so as to have the flow rate control characteristics shown in FIG. 11, first, a control fluid is supplied to the inlet flow path 4, a predetermined applied magnetic force is applied to the coil 32, and fixed. A suction force is generated in the iron core 30 (see FIGS. 1 and 3). Then, the plunger 25 is sucked into the fixed iron core 30, the valve seat 14 is separated from the valve seat 8, and the control fluid is controlled in flow rate and discharged from the outlet channel 3 (see FIG. 2).
[0056]
Therefore, the holding member 13 is screwed into the body 2 while measuring the flow rate of the control fluid discharged from the outlet channel 3. When the holding member 13 is screwed into the body 2 by a predetermined amount, the outer peripheral fixing portion 18 of the leaf spring 10 bends between the holding member 13 and the body 2 and presses the leaf spring 10 against the step 9 of the body 2 so as to be the reference plane. The holding member 13 is allowed to move arbitrarily by the spring force caused by the bending (see FIG. 2). Since the holding iron 13 is held by the holding member 13 and the plunger 25 is fixed to the leaf spring 10, the distance between the fixed iron core 30 and the plunger 25 is screwed into the body 2. The suction force characteristic changes according to the amount (see FIG. 10).
[0057]
As shown in FIG. 11, the electromagnetic proportional valve 1 has a proportional relationship between the flow rate that the valve seat 14 separates and controls from the valve seat 8 and the magnetic force due to the current applied to the coil 32. The valve opening start position L0 that begins to separate from 8 varies depending on the suction force characteristics shown in FIG. Therefore, until the electromagnetic proportional valve 1 controls the flow rate corresponding to the magnetic force due to the current applied to the coil 32 (for example, when the flow rate control characteristic of FIG. 11 is obtained, the flow rate is 150% with respect to the applied magnetic force of 300AT). When the holding member 13 is screwed into the recess 6 of the body 2, the distance between the fixed iron core 30 and the plunger 25 is set to a predetermined value, and the attractive force characteristic shown in the spring diagram K of FIG. 10 is obtained. The valve opening start position L0 is uniquely determined. Thereby, all the electromagnetic proportional valves 1 are assembled so as to have a certain level of flow rate control characteristics shown in FIG. 11, and the same product quality can be obtained.
[0058]
Therefore, according to the electromagnetic proportional valve 1 of the present embodiment, in order to assemble the electromagnetic proportional valve 1 having the same product quality, after assembling and adjusting the component dimensions, or after disassembling the components and replacing the spacers, There is no need to reassemble, and the assembly adjustment of the parts can be easily adjusted.
[0059]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various applications are possible.
[0060]
(1) For example, in the said embodiment, the outer peripheral fixing | fixed part 18 of the leaf | plate spring 10 was bent, the bending part 22 was provided, and it was set as the positioning mechanism. On the other hand, as in the conventional leaf spring (see FIG. 8), the outer periphery fixing portion of the leaf spring may be formed in a ring shape, and the positioning mechanism may be formed using another member such as a ring washer.
[0061]
(2) For example, in the above embodiment, the fitting member 31 is disposed between the holding member 13 and the fixed iron core 30 with the opening portion facing upward. On the other hand, the fitting member 31 may be disposed between the holding member 13 and the fixed iron core 30 with the opening facing downward. Moreover, you may make it give stronger spring force by forming the end surface on the opposite side to the end surface in which the opening part of the fitting member was formed in cross-sectional arc shape.
[0062]
【The invention's effect】
An electromagnetic proportional valve according to the present invention houses a fixed iron core that generates an attractive force according to an electric current applied to a coil, a movable iron core that is attracted to the fixed iron core, a valve element that is fixed to the movable iron core, and a valve element. A valve chamber that communicates with the inlet channel and the outlet channel, a valve seat that is provided in the valve chamber and contacts or separates from the valve body, and a valve that is fixed to the movable core and fixed to the valve body. A leaf spring that applies a load in the closing direction and a holding member that holds the fixed iron core and holds the plate spring between the body and the body are provided. In an electromagnetic proportional valve that controls the stroke amount of the valve body by balancing with the force that presses the valve body against the valve seat, the holding member and the body are screwed together, and between the leaf spring and the body When the holding member is screwed into the body, the leaf spring is used as a reference While being aligned in, since it has a positioning mechanism that allows any movement of the holding member, the assembly and adjustment of parts can be easily performed.
[0063]
In addition, according to the method for assembling an electromagnetic proportional valve according to the present invention, a fixed iron core that generates a suction force according to an electric current applied to the coil, a movable iron core that is attracted to the fixed iron core, and a valve that is fixed to the movable iron core Body, a body formed so that a valve chamber for housing the valve body communicates with the inlet channel and the outlet channel, a valve seat provided in the valve chamber and contacting or separating from the valve body, and a movable iron core An inner peripheral fixed portion fixed to the inner peripheral fixed portion, connected to the inner peripheral fixed portion outwardly, a plurality of beams formed to draw a curve, and the inner peripheral fixed portion via the beams, A leaf spring consisting of an outer peripheral fixed portion bent from the connection portion with the beam as a base, and a fixed iron core are held and screwed to the body to connect the leaf spring to the body. A control member having a holding member sandwiched between the control fluid and the inlet flow path. While supplying a predetermined amount of current to the coil and measuring the flow rate of the control fluid discharged from the outlet channel, the holding member is screwed into the body and the outer periphery of the leaf spring between the holding member and the body When the flow rate corresponding to the current applied to the coil is measured while the fixing portion is sandwiched, the holding member is stopped from being screwed into the body, so that assembly adjustment of the parts can be easily performed.
[Brief description of the drawings]
FIG. 1 is an enlarged sectional view of a valve portion in a state where an electromagnetic proportional valve is closed according to an embodiment of the present invention.
FIG. 2 is an enlarged cross-sectional view of the valve portion in a state where the electromagnetic proportional valve is open.
FIG. 3 is a cross-sectional view of an electromagnetic proportional valve.
FIG. 4 is a plan view of the leaf spring in the same manner.
FIG. 5 is a side view of the leaf spring.
FIG. 6 is a plan view of the leaf spring fixed to the plunger.
FIG. 7 is a cross-sectional view of a conventional electromagnetic proportional valve.
FIG. 8 is a front view showing an example of a leaf spring used in a conventional electromagnetic proportional valve.
FIG. 9 is an enlarged sectional view of a valve portion of a conventional electromagnetic proportional valve.
FIG. 10 is a diagram showing a suction force characteristic of an electromagnetic proportional valve.
FIG. 11 is a diagram showing a flow control characteristic of an electromagnetic proportional valve.
[Explanation of symbols]
1 Solenoid proportional valve
2 Body
3 Inlet channel
4 outlet channel
5 Valve room
8 Valve seat
10 leaf spring
13 Holding member
30 Fixed iron core
31 Insertion member
16 Inner circumference fixing part
17 Beam
18 Peripheral fixing part
19 holes
20 protrusions
32 coils
25 Plunger

Claims

A fixed iron core that generates a suction force according to the current applied to the coil, a movable iron core that is attracted to the fixed iron core, a valve element that is fixed to the movable iron core, and a valve chamber that houses the valve element are provided as an inlet flow. A body formed so as to communicate with the passage and the outlet flow path, a valve seat provided in the valve chamber with which the valve body abuts or separates, and a valve closing direction fixed to the movable core and fixed to the valve body And a holding member that holds the fixed iron core and holds the plate spring between the body and the holding spring, the suction force generated by the fixed iron core; In the electromagnetic proportional valve that controls the stroke amount of the valve body by balancing with the force of the leaf spring pressing the valve body against the valve seat,
The holding member and the body are screwed and connected,
The leaf spring is
An inner peripheral fixed part fixed to the movable iron core, an outer peripheral connected to the inner peripheral fixed part, and a plurality of beams formed to draw a curve, via the beams A plurality of outer peripheral fixing portions connected to the inner peripheral fixing portion and sandwiched between the holding member and the body;
The electromagnetic proportional valve, wherein the outer peripheral fixing portion is bent .

In the electromagnetic proportional valve according to claim 1,
The leaf spring is
The inner periphery fixing part is formed in a C shape having a notch hole in the center part,
The proportional solenoid valve according to claim 1, wherein the hole is connected to one of a plurality of long holes formed by the outer periphery fixing portion, the beam, and the inner periphery fixing portion.

In the electromagnetic proportional valve according to claim 1 or 2,
The valve body is formed of an elastic body having thermoplasticity,
The leaf spring is provided with an inward projection that holds the valve body on the inner peripheral fixed portion, and is welded to the movable iron core.

In the electromagnetic proportional valve according to any one of claims 1 to 3,
An electromagnetic proportional valve, wherein the valve body is mirror-finished on a surface abutting against the valve seat.

In the electromagnetic proportional valve according to any one of claims 1 to 4,
Having an annular fitting member formed in a U-shaped cross section;
The electromagnetic proportional valve, wherein the fitting member is fixed to an inner peripheral surface of the holding member, and is press-fitted so that the fixed iron core protrudes into the valve chamber.

A fixed iron core that generates an attractive force according to the current applied to the coil;
A movable iron core sucked into the fixed iron core;
A valve body fixed to the movable core;
A body formed such that a valve chamber that houses the valve body communicates with an inlet channel and an outlet channel;
A valve seat provided in the valve chamber and contacting or separating from the valve body;
An inner peripheral fixed part fixed to the movable iron core, an outer peripheral connected to the inner peripheral fixed part, a plurality of beams formed so as to draw a curve, and via the beams A leaf spring composed of an outer periphery fixing portion which is connected to the inner periphery fixing portion and is subjected to a bending process based on a connection portion with the beam;
Using an electromagnetic proportional valve having a holding member that holds the fixed iron core and is screwed to the body to hold the leaf spring between the body and the holding member.
Supplying a control fluid to the inlet channel and supplying a predetermined amount of current to the coil;
While measuring the flow rate of the control fluid discharged from the outlet channel, the holding member is screwed into the body, and the outer periphery fixing portion of the leaf spring is sandwiched between the holding member and the body,
The method of assembling an electromagnetic proportional valve, wherein the screwing of the holding member into the body is stopped when a flow rate corresponding to the current applied to the coil is measured.