JP2004308703A

JP2004308703A - Electromagnetic type fuel injection valve

Info

Publication number: JP2004308703A
Application number: JP2003100140A
Authority: JP
Inventors: Akira Akabane; 明赤羽根
Original assignee: Keihin Corp
Current assignee: Keihin Corp
Priority date: 2003-04-03
Filing date: 2003-04-03
Publication date: 2004-11-04
Anticipated expiration: 2023-04-03
Also published as: JP3954982B2

Abstract

<P>PROBLEM TO BE SOLVED: To thin down a yoke while securing a wide magnetic passage by enabling filling of synthetic resin into a coil housing without providing a cutout part on the flanged yoke integrally formed with a fixed core, in an electromagnetic type fuel injection valve. <P>SOLUTION: In the electromagnetic type fuel injection valve, both ends of a valve housing 2 housing a coil 30 are respectively connected to an outer periphery of the valve housing 2 and the flanged yoke 5a integrated with the fixed core 5 to constitute a valve body 1, the synthetic resin is filled in the coil housing 31, and a coating body 32 covering the valve body 1 and coupler 34 are integrally formed by molding with the synthetic resin. The yoke 5a is formed in a discoid shape to be connected to the coil housing 31 over its entire circumference, the coupler 34 is arranged so as to project to one side of the coil housing 31. The coil hosing 31 is provided with the axial cutout part 31a for pouring the synthetic resin into the coil housing 31 when the coupler 34 and the coating body 32 are formed by molding. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は，主として内燃機関の燃料供給系に使用される電磁式燃料噴射弁に関し，特に，弁ハウジングと，この弁ハウジングに非磁性筒体を介して連結される固定コアと，この固定コアの外周に配設されるコイルを収容して一端が弁ハウジングの外周に連結されるコイルハウジングと，前記固定コアに一体に形成されてコイルハウジングの他端部に連結されるフランジ状のヨークとで弁ボディを構成し，前記コイルハウジング内に充填されると共に，弁ボディの外周を覆う被覆体と，前記コイルに接続された接続端子を保持するカプラとを合成樹脂により一体にモールド成形した，電磁式燃料噴射弁の改良に関する。
【０００２】
【従来の技術】
かゝる電磁式燃料噴射弁は，例えば特許文献１に開示されるように，既に知られている。
【０００３】
【特許文献１】
特開２００２−４０１３号公報
【０００４】
【発明が解決しようとする課題】
ところで，特許文献１に開示された電磁式燃料噴射弁では，合成樹脂製の被覆体の成形時，その合成樹脂をコイルハウジングに流入させるために，コイルハウジングに連結されるフランジ状のヨークの外周に複数の切欠き部を形成している。この場合，上記切欠き部によりヨーク及びコイルハウジング間の磁路が絞られるのを補うため，ヨークを比較的厚肉に形成しているが，そうすることは電磁式燃料噴射弁の軸方向寸法を多少とも増加させるので，電磁式燃料噴射弁のコンパクト化の妨げとなる。
【０００５】
本発明は，かゝる事情に鑑みてなされたもので，フランジ状のヨークに切欠き部を設けずとも，コイルハウジング内への合成樹脂の充填を可能して，前記ヨークの薄肉化と磁路の確保との両立を図ることができる電磁式燃料噴射弁を提供することを目的とする。
【０００６】
【課題を解決するための手段】
上記目的を達成するために，本発明は，弁ハウジングと，この弁ハウジングに非磁性筒体を介して連結される固定コアと，この固定コアの外周に配設されるコイルを収容して一端が弁ハウジングの外周に連結されるコイルハウジングと，前記固定コアに一体に形成されてコイルハウジングの他端部に連結されるフランジ状のヨークとで弁ボディを構成し，前記コイルハウジング内に充填されると共に，弁ボディの外周を覆う被覆体と，前記コイルに接続された接続端子を保持するカプラとを合成樹脂により一体にモールド成形した，電磁式燃料噴射弁において，前記ヨークを，前記コイルハウジングの他端部にその全周に亙り連結すべく円板状に形成し，前記カプラを前記コイルハウジングの一側方に突出するように配置し，前記コイルハウジングには，前記カプラ及び被覆体の合成樹脂によるモールド成形時，その合成樹脂を該コイルハウジング内に流入させる軸方向の切欠き部を前記カプラに向けて設けたことを特徴とする。
【０００７】
この特徴によれば，カプラ及び被覆体の合成樹脂によるモールド成形時，合成樹脂をカプラの成形部からコイルハウジングの切欠き部を通してコイルハウジング内にスムーズに充填することができ，同時にカプラの成形部から被覆体の成形部にも充填することができ，これによりカプラ及び被覆体の一体成形と共に，合成樹脂によるコイルの埋封を確実に行うことができる。
【０００８】
しかもフランジ状のヨークは，切欠き部のない円板状としてコイルハウジングに，連結されるから，ヨークを薄肉に形成してもヨーク及びコイルハウジング間には充分広い磁路を確保することができ，したがってヨークの薄肉化が可能となる。
【０００９】
さらにコイルハウジングの一側方にカプラを配置することにより，カプラによる電磁式燃料噴射弁の軸方向長さの増加を抑えることができ，前記ヨークの薄肉化と相俟って電磁式燃料噴射弁のコンパクト化に資することができる。
【００１０】
【発明の実施の形態】
本発明の実施の形態を，添付図面に示す本発明の実施例に基づいて以下に説明する。
【００１１】
図１は本発明に係る電磁式燃料噴射弁を，スロットルボディへの取り付け状態で示す縦断面図，図２は上記燃料噴射弁の拡大縦断面図，図３は図２の３−３線断面図，図４は図２の４−４線断面図，図５はリテーナパイプの固定要領を示す，図３に対応する断面図，図６はコイルハウジングの斜視図である。
【００１２】
先ず，図２により，電磁式燃料噴射弁Ｉの構成について詳細に説明する。電磁式燃料噴射弁Ｉの弁ハウジング２は，前端に弁座８を有する円筒状の弁座部材３と，この弁座部材３の後端部に同軸に結合される磁性筒体４と，この磁性筒体４の後端に同軸に結合される非磁性筒体６とで構成される。
【００１３】
弁座部材３は，その外周面から環状肩部３ｂを存して磁性筒体４側に突出する連結筒部３ａを後端部に有しており，この連結筒部３ａを磁性筒体４の前端部内周面に圧入して，磁性筒体４の前端面を環状肩部３ｂに当接させることにより，弁座部材３及び磁性筒体４は互いに同軸且つ液密に結合される。磁性筒体４及び非磁性筒体６は，対向端面を突き合わせて全周に亙りレーザビーム溶接により互いに同軸且つ液密に結合される。
【００１４】
弁座部材３は，その前端面に開口する弁孔７と，この弁孔７の内端に連なる円錐状の弁座８と，この弁座８の大径部に連なる円筒状のガイド孔９とを備えている。弁座部材３の前端面には，上記弁孔７と連通する複数の燃料噴孔１１を有する鋼板製のインジェクタプレート１０が液密に全周溶接される。
【００１５】
非磁性筒体６の内周面には，その後端側から中空円筒状の固定コア５が液密に圧入固定される。その際，非磁性筒体６の前端部には，固定コア５と嵌合しない部分が残され，その部分から弁座部材３に至る弁ハウジング２内に弁組立体Ｖが収容される。
【００１６】
弁組立体Ｖは，前記弁座８と協働して弁孔７を開閉する半球状の弁部１６及びそれを支持する弁杆部１７からなる弁体１８と，弁杆部１７に連結され，磁性筒体４から非磁性筒体６に跨がって，それらに挿入されて固定コア５に同軸で対置される可動コア１２とからなっている。弁杆部１７は，前記ガイド孔９より小径に形成されており，その外周には，半径方向外方に突出して，前記ガイド孔９の内周面に摺動可能に支承される前後一対のジャーナル部１７ａ，１７ａが一体に形成される。その際，両ジャーナル部１７ａ，１７ａは，両者の軸方向間隔を極力あけて配置される。
【００１７】
弁組立体Ｖには，可動コア１２の後端面から始まり半球状弁部１６の球面中心Ｏを超えて行き止まりとなる縦孔１９と，この縦孔１９を，可動コア１２外周面に連通する複数の第１横孔２０ａと，同縦孔１９を両ジャーナル部１７ａ，１７ａ間の弁杆部１７外周面に連通する複数の第２横孔２０ｂと，同縦孔１９を前側のジャーナル部１７ａより弁部１８寄りで弁杆部１７外周に連通する複数の第３横孔２０ｃとが設けられる。その際，第３横孔２０ｃは弁部１８の球面中心Ｏよりも前寄りに配置されることが望ましく，また前側のジャーナル部１７ａは，弁部１６の球面中心Ｏに極力近接して配置することが望ましい。
【００１８】
縦孔１９の途中には，固定コア５側を向いた環状のばね座２４が形成されている。
【００１９】
固定コア５は，可動コア１２の縦孔１９と連通する中空部２１を有し，この中空部２１に内部が連続する燃料入口筒２６が固定コア５の後端に一体に連設される。燃料入口筒２６は，固定コア５の後端に連なる縮径部２６ａと，それに続く拡径部２６ｂとからなっており，その縮径部２６ａから中空部２１に亙り挿入，固定されるリテーナパイプ２３と前記ばね座２４との間に可動コア１２を弁体１８の閉弁側に付勢する弁ばね２２が縮設される。その際，リテーナパイプ２３の中空部２１への挿入深さにより弁ばね２２のセット荷重が調整される。そのセット荷重の調整については，後で詳述する。
【００２０】
燃料入口筒２６の拡径部２６ｂには燃料フィルタ２７が装着される。
【００２１】
弁組立体Ｖにおいて，可動コア１２には，固定コア５の吸引面５ａと対向する吸引面１２ａに嵌合凹部１３が形成され，この嵌合凹部１３に，前記弁ばね２２を囲繞するカラー状のストッパ要素１４が圧入により固定され，又は嵌合後，溶接もしくはカシメにより固定される。ストッパ要素１４は非磁性材料で構成される。
【００２２】
上記ストッパ要素１４は可動コア１２の吸引面１２ａから突出していて，通常，弁体１８の開弁ストロークに相当する間隙ｓを存して固定コア５の吸引面５ａと対置される。ストッパ要素１４の吸引面１２ａから突出量ｇは，コイル３０の励磁により可動コア１２が固定コア５に吸引されて，可動コア１２のストッパ要素１４が固定コア５の吸引面５ａに当接したとき，両コア５，１２の吸引面５ａ，１２ａ間に形成されるエアギャップに相当する。
【００２３】
弁ハウジング２の外周には，固定コア５及び可動コア１２に対応してコイル組立体２８が嵌装される。このコイル組立体２８は，磁性筒体４の後端部から非磁性筒体６全体にかけてそれらの外周面に嵌合するボビン２９と，これに巻装されるコイル３０とからなっており，このコイル組立体２８を囲繞する円筒状のコイルハウジング３１の前端が磁性筒体４の外周面に圧入後，溶接される。
【００２４】
コイルハウジング３１には，その後端側に開口する軸方向の切欠き部３１ａが形成されている（図４及び図６参照）。
【００２５】
固定コア５の後端には，その外周からフランジ状に突出する，切欠きの無い円板状のヨーク５ｂが一体に形成され，このヨーク５ｂは，上記コイルハウジング３１後端部の内周面に圧入され，その後，必要に応じて溶接される。
【００２６】
以上において，弁ハウジング２，固定コア５，ヨーク５ｂ，燃料入口筒２６及びコイルハウジング３１によって弁ボディ１が構成される。この弁ボディ１の外周には，弁座部材３及び磁性筒体４の前端部と，燃料入口筒２６の拡径部２６ｂの後端部とを残して，その外周を覆う被覆体３２と，コイルハウジング３１の一側方に突出するカプラ３４とが合成樹脂により射出成形，即ちモールド成形される。その成形の際，溶融状態の合成樹脂がカプラ３４の成形部からコイルハウジング３１の切欠き部３１ａを通してコイルハウジング３１内にスムーズに充填されるように，カプラ３４及び切欠き部３１ａは互いに対向するように配置されている。そしてコイルハウジング３１に充填される合成樹脂によってコイル３０と，コイル３０に接続されてカプラ３４内に配置される接続端子３３とが埋封される。
【００２７】
燃料入口筒２６の拡径部２６ｂはコイルハウジング３１より小径になっており，これに伴ない被覆体３２は，コイルハウジング３１を覆う大径部３２ａと，燃料入口筒２６を覆う小径部３２ｂとの境界の段部３２ｃとからなるように成形され，また前記カプラ３４は，段部３２ｃに近接して成形される。
【００２８】
図２及び図３に示すように，上記を小径部３２ｂには，同一直径線に並んで燃料入口筒２６の縮径部２６ａの外周面に達する一対の工具孔４０，４０が設けられる。小径部３２ｂの，これら工具孔４０，４０に露出する部分は制御部Ａ，Ａとされる。
【００２９】
而して，前記弁ばね２２のセット荷重の調整に当たっては，燃料入口筒２６の縮径部２６ａから固定コア５の中空部２１にリテーナパイプ２３が隙間嵌めにより挿入され，その挿入深さを加減することにより，弁ばね２２のセット荷重は調整される。その調整後，図５に示すように，工具孔４０，４０に挿入したカシメ工具Ｔ，Ｔをもって前記記制御部Ａ，Ａを半径方向内方へカシメることにより，燃料燃料入口筒２６にリテーナパイプ２３が固定される。
【００３０】
こうして，弁ばね２２のセット荷重が調整された後，被覆体３２の小径部３２ｂ外周面には，ゴム等の弾性材からなるクッションリング３５が工具孔４０，４０の開口部を閉鎖するように嵌合される。このクッションリング３５は，その内径に小径部３２ｂ外周面に対する締め代が付与されていて，小径部３２ｂ外周面に全周に亙り水密に密着するようになっており，これにより工具孔４０，４０を水密に閉鎖することができる。被覆体３２の大径部３２ａ及び小径部３２ｂ間の段部３２ｃは，このクッションリング３５の一端面を支承する座面に形成される。
【００３１】
また弁ハウジング２の，被覆体３２の前端面から露出した部分の外周面にもクッションリング３６が嵌合され，これは被覆体３２の前端面で支承される。
【００３２】
上記燃料噴射弁Ｉは，図１に示すように，エンジンの吸気系の一部を構成するスロットルボディＢに取り付けられる。
【００３３】
即ち，エンジンのスロットルボディＢの一側壁には，スロットルバルブ４１より下流の吸気道４２に，その下流側に向かって斜めに開口する噴射弁受け入れ孔４３と，その後端に連なる環状凹部４４とが設けられ，噴射弁受け入れ孔４３に燃料噴射弁Ｉの弁座部材３が，また環状凹部４４にクッションリング３６がそれぞれ挿入される。
【００３４】
またスロットルボディＢの一側壁には，燃料ポンプの吐出燃料を誘導する燃料供給管４５を支持するブラケット４６がボルト４８で固着される。この燃料供給管４５は一側にジョイント筒４７を一体に形成しており，このジョイント筒４７は，燃料噴射弁Ｉの被覆体３２の小径部３２ｂ後端部にシール部材３７を介して嵌合すると共に，このジョイント筒４７前端のフランジ部４７ａでクッションリング３５を座面３２ｃ側，即ちスロットルボディＢ側に押圧するように配置される。こうして燃料噴射弁Ｉは，前後のクッションリング３５，３６を介してスロットルボディＢ及び燃料供給管４５との間で弾性支持される。その際，フランジ部４７ａ及び座面３２ｃは，クッションリング３５の各端面に全周に亙り水密に密着し，これによっても，前記工具孔４０，４０は外部と水密に遮断される。
【００３５】
次に，この実施例の作用について説明する。
【００３６】
コイル３０を通電により励磁すると，それにより生ずる磁束が固定コア５，コイルハウジング３１，磁性筒体４及び可動コア１２を順次走り，その磁力により弁組立体Ｖの可動コア１２が弁ばね２２のセット荷重に抗して固定コア５に吸引され，弁体１８が弁座８から離座するので，弁孔７が開放され，弁座部材３内の高圧燃料が弁孔７を出て，燃料噴孔１１からスロットルボディＢの吸気道４２下流側に向けて噴射される。
【００３７】
このとき，弁組立体Ｖの可動コア１２に嵌合固定されたストッパ要素１４が固定コア５の吸引面５ａに当接することにより，弁体１８の開弁限界が規定され，可動コア１２の吸引面１２ａは，エアギャップｇを存して固定コア５の吸引面５ａと対向し，固定コア５との直接接触が回避される。特にストッパ要素１４の，可動コア１２の吸引面１２ａからの突出量の寸法管理により，上記エアギャップｇを精密且つ容易に得ることができ，ストッパ要素１４が非磁性であることゝ相俟って，コイル３０の消磁時の両コア５，１２間の残留磁気は速やかに消失して，弁体１８の閉弁応答性を高めることができる。
【００３８】
弁組立体Ｖは，その開閉動作中，弁杆部１７上の前後一対のジャーナル部１７ａ，１７ａが弁座部材３の内周面に摺動することにより，常に倒れのない適正な姿勢に保持されるので，燃料噴射特性の安定化を図ることができる。
【００３９】
また弁組立体Ｖの外周面には，縦孔１９に連通する第１〜第３横孔２０ａ〜２０ｃが開口しているから，縦孔１９の流入した燃料は，第１〜第３横孔２０ａ〜２０ｃを通して，ジャーナル部１７ａ，１７ａの摺動面，並びに可動コア１２及び磁性筒体４間の間隙に供給され，ジャーナル部１７ａ，１７ａのの摺動面の潤滑は勿論，可動コア１２及び磁性筒体４の冷却を効果的に行うことができ，弁組立体Ｖの応答性及び耐摩耗性の向上を図ることができる。
【００４０】
また可動コア１２を横切る第２横孔２０ｂは，コイル３０の励，消磁時，可動コア１２に渦電流が生ずることを抑え，渦電流に起因する可動コア１２の加熱を防ぐことができる。
【００４１】
さらに半球状の弁部１６の球面近くまで延びる深い縦孔１９は，第１〜第３横孔２０ａ〜２０ｃと共に，燃料通路の役目を果す他に，弁組立体Ｖの贅肉を除去する役目をも果たし，弁組立体Ｖの軽量化，延いては応答性の向上に寄与する。
【００４２】
ところで，このような電磁式燃料噴射弁Ｉにおいて，カプラ３４及び被覆体３２の合成樹脂によるモールド成形時，合成樹脂をカプラ３４の成形部からコイルハウジング３１の切欠き部３１ａを通してコイルハウジング３１内にスムーズに充填することができ，同時にカプラ３４の成形部から被覆体３２の成形部にも充填することができ，これによりカプラ３４及び被覆体３２の一体成形と共に，合成樹脂によるコイル３０の埋封を確実に行うことができる。
【００４３】
しかもフランジ状のヨーク５ｂは，切欠き部のない円板状としてコイルハウジング３１に圧入されるから，ヨーク５ｂを薄肉に形成してもヨーク５ｂ及びコイルハウジング３１間には充分広い磁路を確保することができ，したがってヨークの薄肉化が可能となる。
【００４４】
さらにコイルハウジング３１の一側方をカプラ３４の設置スペースに利用することにより，カプラ３４による電磁式燃料噴射弁Ｉの軸方向長さの増加を抑えることができ，前記ヨーク５ｂの薄肉化と相俟って電磁式燃料噴射弁Ｉのコンパクト化を大いに図ることができる。
【００４５】
本発明は上記実施例に限定されるものではなく，その要旨を逸脱しない範囲で種々の設計変更が可能である。
【００４６】
【発明の効果】
以上のように本発明によれば，弁ハウジングと，この弁ハウジングに非磁性筒体を介して連結される固定コアと，この固定コアの外周に配設されるコイルを収容して一端が弁ハウジングの外周に連結されるコイルハウジングと，前記固定コアに一体に形成されてコイルハウジングの他端部に連結されるフランジ状のヨークとで弁ボディを構成し，前記コイルハウジング内に充填されると共に，弁ボディの外周を覆う被覆体と，前記コイルに接続された接続端子を保持するカプラとを合成樹脂により一体にモールド成形した，電磁式燃料噴射弁において，前記ヨークを，前記コイルハウジングの他端部にその全周に亙り連結すべく円板状に形成し，前記カプラを前記コイルハウジングの一側方に突出するように配置し，前記コイルハウジングには，前記カプラ及び被覆体の合成樹脂によるモールド成形時，その合成樹脂を該コイルハウジング内に流入させる軸方向の切欠き部を前記カプラに向けて設けたので，カプラ及び被覆体の合成樹脂によるモールド成形時，合成樹脂をカプラの成形部からコイルハウジングの切欠き部を通してコイルハウジング内にスムーズに充填することができ，同時にカプラの成形部から被覆体の成形部にも充填することができ，これによりカプラ及び被覆体の一体成形と共に，合成樹脂によるコイルの埋封を確実に行うことができる。しかもフランジ状のヨークは，切欠き部のない円板状としてコイルハウジングに，連結されるから，ヨークを薄肉に形成してもヨーク及びコイルハウジング間には充分広い磁路を確保することができ，したがってヨークの薄肉化が可能となる。さらにコイルハウジングの一側方にカプラを配置することにより，カプラによる電磁式燃料噴射弁の軸方向長さの増加を抑えることができ，前記ヨークの薄肉化と相俟って電磁式燃料噴射弁のコンパクト化に資することができる。
【図面の簡単な説明】
【図１】本発明に係る電磁式燃料噴射弁を，スロットルボディへの取り付け状態で示す縦断面図
【図２】上記燃料噴射弁の拡大縦断面図
【図３】図２の３−３線断面図
【図４】図２の４−４線断面図
【図５】リテーナパイプの固定要領を示す，図３に対応する断面図
【図６】コイルハウジングの斜視図
【符号の説明】
Ｉ・・・・・電磁式燃料噴射弁
１・・・・・弁ボディ
２・・・・・弁ハウジング
５・・・・・固定コア
６・・・・・非磁性筒体
３０・・・・コイル
３１・・・・コイルハウジング
３１ａ・・・切欠き部
３２・・・・被覆体
３３・・・・接続端子
３４・・・・カプラ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electromagnetic fuel injection valve mainly used for a fuel supply system of an internal combustion engine, and in particular, to a valve housing, a fixed core connected to the valve housing via a non-magnetic cylinder, and a fixed core of the fixed core. A coil housing which accommodates a coil disposed on the outer periphery and has one end connected to the outer periphery of the valve housing, and a flange-like yoke formed integrally with the fixed core and connected to the other end of the coil housing. A valve body, wherein a cover which is filled in the coil housing and covers an outer periphery of the valve body, and a coupler which holds a connection terminal connected to the coil, are integrally molded with a synthetic resin; The present invention relates to improvement of a fuel injection valve.
[0002]
[Prior art]
Such an electromagnetic fuel injection valve is already known, for example, as disclosed in Patent Document 1.
[0003]
[Patent Document 1]
JP-A-2002-4013
[Problems to be solved by the invention]
By the way, in the electromagnetic fuel injection valve disclosed in Patent Document 1, at the time of molding a synthetic resin cover, in order to allow the synthetic resin to flow into the coil housing, the outer periphery of a flange-shaped yoke connected to the coil housing is formed. Are formed with a plurality of notches. In this case, the yoke is formed to have a relatively large thickness in order to compensate for the narrowing of the magnetic path between the yoke and the coil housing by the notch, but this is done in accordance with the axial dimension of the electromagnetic fuel injection valve. , Which hinders the compactness of the electromagnetic fuel injection valve.
[0005]
SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is possible to fill a coil housing with a synthetic resin without providing a notch in a flange-like yoke, thereby reducing the thickness of the yoke and reducing the magnetic field. It is an object of the present invention to provide an electromagnetic fuel injection valve that can achieve compatibility with securing a road.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a valve housing, a fixed core connected to the valve housing via a non-magnetic cylinder, and a coil housing disposed on an outer periphery of the fixed core. Constitutes a valve body with a coil housing connected to the outer periphery of the valve housing and a flange-shaped yoke formed integrally with the fixed core and connected to the other end of the coil housing, and filled in the coil housing. And a cover covering the outer periphery of the valve body and a coupler holding a connection terminal connected to the coil are integrally molded of synthetic resin. The coupler is formed in a disk shape so as to be connected to the other end of the housing over the entire circumference thereof, and the coupler is disposed so as to protrude to one side of the coil housing. The ring, characterized in that the at molding with synthetic resin of the coupler and the cover member, provided with a notch in the axial direction to flow into the synthetic resin into the coil housing toward the coupler.
[0007]
According to this feature, when the coupler and the cover are molded with the synthetic resin, the synthetic resin can be smoothly filled into the coil housing from the molded portion of the coupler through the cutout portion of the coil housing, and at the same time, the molded portion of the coupler is formed. Thus, it is possible to fill the molded portion of the cover with the resin, thereby securely integrating the coupler and the cover and also burying the coil with the synthetic resin.
[0008]
Moreover, since the flange-shaped yoke is connected to the coil housing as a disk having no notch, a sufficiently wide magnetic path can be secured between the yoke and the coil housing even if the yoke is formed thin. Therefore, the yoke can be made thinner.
[0009]
Further, by disposing the coupler on one side of the coil housing, an increase in the axial length of the electromagnetic fuel injection valve due to the coupler can be suppressed. Can be made compact.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described below based on embodiments of the present invention shown in the accompanying drawings.
[0011]
1 is a longitudinal sectional view showing an electromagnetic fuel injection valve according to the present invention mounted on a throttle body, FIG. 2 is an enlarged longitudinal sectional view of the fuel injection valve, and FIG. 3 is a sectional view taken along line 3-3 in FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 2, FIG. 5 is a cross-sectional view corresponding to FIG. 3, and FIG. 6 is a perspective view of a coil housing, showing a procedure for fixing the retainer pipe.
[0012]
First, the configuration of the electromagnetic fuel injection valve I will be described in detail with reference to FIG. The valve housing 2 of the electromagnetic fuel injection valve I includes a cylindrical valve seat member 3 having a valve seat 8 at a front end, a magnetic cylinder 4 coaxially coupled to a rear end of the valve seat member 3, A non-magnetic cylinder 6 is coaxially coupled to the rear end of the magnetic cylinder 4.
[0013]
The valve seat member 3 has, at its rear end, a connecting cylinder 3a projecting toward the magnetic cylinder 4 with an annular shoulder 3b from the outer peripheral surface thereof. The valve seat member 3 and the magnetic cylinder 4 are coaxially and liquid-tightly connected to each other by press-fitting the inner peripheral surface of the front end of the magnetic cylinder 4 and bringing the front end surface of the magnetic cylinder 4 into contact with the annular shoulder 3b. The magnetic cylinder 4 and the non-magnetic cylinder 6 are coaxially and liquid-tightly joined to each other by laser beam welding over the entire circumference with their facing end faces abutting.
[0014]
The valve seat member 3 has a valve hole 7 opened at the front end surface thereof, a conical valve seat 8 connected to the inner end of the valve hole 7, and a cylindrical guide hole 9 connected to a large diameter portion of the valve seat 8. And An injector plate 10 made of a steel plate having a plurality of fuel injection holes 11 communicating with the valve hole 7 is liquid-tightly welded to the front end surface of the valve seat member 3 in a liquid-tight manner.
[0015]
A hollow cylindrical fixed core 5 is press-fitted and fixed to the inner peripheral surface of the non-magnetic cylinder 6 from the rear end side in a liquid-tight manner. At this time, a portion that does not fit with the fixed core 5 is left at the front end of the non-magnetic cylinder 6, and the valve assembly V is accommodated in the valve housing 2 extending from the portion to the valve seat member 3.
[0016]
The valve assembly V is connected to a valve body 18 comprising a hemispherical valve part 16 for opening and closing the valve hole 7 in cooperation with the valve seat 8 and a valve rod part 17 for supporting the same, and a valve rod part 17. And a movable core 12 which extends from the magnetic cylinder 4 to the non-magnetic cylinder 6, is inserted therein, and is coaxially opposed to the fixed core 5. The valve rod portion 17 is formed to have a smaller diameter than the guide hole 9, and has a pair of front and rear portions protruding radially outward on the outer periphery thereof and slidably supported on the inner peripheral surface of the guide hole 9. The journal portions 17a, 17a are formed integrally. At this time, the two journal portions 17a, 17a are arranged with an axial space therebetween as much as possible.
[0017]
The valve assembly V has a vertical hole 19 starting from the rear end face of the movable core 12 and reaching a dead end beyond the spherical center O of the hemispherical valve portion 16, and a plurality of the vertical holes 19 communicating with the outer peripheral surface of the movable core 12. The first horizontal hole 20a, the plurality of second horizontal holes 20b that connect the vertical hole 19 to the outer peripheral surface of the valve rod portion 17 between the two journal portions 17a, 17a, and the vertical hole 19 are connected to the front journal portion 17a. A plurality of third lateral holes 20c communicating with the outer periphery of the valve rod 17 are provided near the valve 18. At this time, it is desirable that the third lateral hole 20c is arranged closer to the front than the spherical center O of the valve portion 18, and the front journal portion 17a is arranged as close as possible to the spherical center O of the valve portion 16. It is desirable.
[0018]
In the middle of the vertical hole 19, an annular spring seat 24 facing the fixed core 5 side is formed.
[0019]
The fixed core 5 has a hollow portion 21 that communicates with the vertical hole 19 of the movable core 12, and a fuel inlet tube 26 whose interior is continuous with the hollow portion 21 is integrally connected to the rear end of the fixed core 5. The fuel inlet tube 26 includes a reduced diameter portion 26a connected to the rear end of the fixed core 5 and a subsequently enlarged diameter portion 26b, and a retainer pipe inserted and fixed from the reduced diameter portion 26a to the hollow portion 21. A valve spring 22 for urging the movable core 12 toward the valve closing side of the valve element 18 is contracted between the valve seat 23 and the spring seat 24. At this time, the set load of the valve spring 22 is adjusted by the insertion depth of the retainer pipe 23 into the hollow portion 21. The adjustment of the set load will be described later in detail.
[0020]
A fuel filter 27 is mounted on the enlarged diameter portion 26b of the fuel inlet cylinder 26.
[0021]
In the valve assembly V, the movable core 12 has a fitting recess 13 formed on the suction surface 12 a facing the suction surface 5 a of the fixed core 5, and the fitting recess 13 has a collar-like shape surrounding the valve spring 22. Is fixed by press-fitting, or after fitting, is fixed by welding or caulking. The stopper element 14 is made of a non-magnetic material.
[0022]
The stopper element 14 protrudes from the suction surface 12a of the movable core 12, and is usually opposed to the suction surface 5a of the fixed core 5 with a gap s corresponding to the valve opening stroke of the valve element 18. The amount g of protrusion of the stopper element 14 from the suction surface 12 a is determined when the movable core 12 is attracted to the fixed core 5 by the excitation of the coil 30 and the stopper element 14 of the movable core 12 contacts the suction surface 5 a of the fixed core 5. And an air gap formed between the suction surfaces 5a, 12a of the cores 5, 12.
[0023]
A coil assembly 28 is fitted around the outer periphery of the valve housing 2 so as to correspond to the fixed core 5 and the movable core 12. The coil assembly 28 includes a bobbin 29 fitted on the outer peripheral surface of the magnetic cylinder 4 from the rear end to the entire non-magnetic cylinder 6, and a coil 30 wound around the bobbin 29. The front end of the cylindrical coil housing 31 surrounding the coil assembly 28 is pressed into the outer peripheral surface of the magnetic cylinder 4 and then welded.
[0024]
The coil housing 31 is formed with an axial cutout portion 31a that opens to the rear end side (see FIGS. 4 and 6).
[0025]
At the rear end of the fixed core 5, there is integrally formed a disk-shaped yoke 5b without a notch, which protrudes from the outer periphery in a flange shape, and this yoke 5b is an inner peripheral surface of the rear end of the coil housing 31. And then welded as needed.
[0026]
As described above, the valve housing 1 is constituted by the valve housing 2, the fixed core 5, the yoke 5b, the fuel inlet tube 26, and the coil housing 31. On the outer periphery of the valve body 1, a cover 32 covering the outer periphery except for the front ends of the valve seat member 3 and the magnetic cylinder 4 and the rear end of the enlarged diameter portion 26 b of the fuel inlet cylinder 26. The coupler 34 protruding to one side of the coil housing 31 is injection-molded, that is, molded with synthetic resin. At the time of the molding, the coupler 34 and the notch 31a are opposed to each other so that the synthetic resin in a molten state is smoothly filled from the molded portion of the coupler 34 into the coil housing 31 through the notch 31a of the coil housing 31. Are arranged as follows. Then, the coil 30 and the connection terminal 33 connected to the coil 30 and arranged in the coupler 34 are embedded with the synthetic resin filled in the coil housing 31.
[0027]
The enlarged diameter portion 26b of the fuel inlet tube 26 has a smaller diameter than the coil housing 31. Accordingly, the covering 32 includes a large diameter portion 32a covering the coil housing 31 and a small diameter portion 32b covering the fuel inlet tube 26. And the coupler 34 is formed close to the step 32c.
[0028]
As shown in FIGS. 2 and 3, the small-diameter portion 32b is provided with a pair of tool holes 40, 40 which are arranged along the same diameter line and reach the outer peripheral surface of the reduced-diameter portion 26a of the fuel inlet cylinder 26. The portions of the small diameter portion 32b exposed to the tool holes 40, 40 are control units A, A.
[0029]
In adjusting the set load of the valve spring 22, the retainer pipe 23 is inserted from the reduced diameter portion 26a of the fuel inlet tube 26 into the hollow portion 21 of the fixed core 5 by a clearance fit, and the insertion depth is adjusted. By doing so, the set load of the valve spring 22 is adjusted. After the adjustment, as shown in FIG. 5, the control portions A, A are caulked radially inward with the caulking tools T, T inserted into the tool holes 40, 40, so that the retainer is inserted into the fuel fuel inlet tube 26. The pipe 23 is fixed.
[0030]
After the set load of the valve spring 22 is adjusted in this manner, a cushion ring 35 made of an elastic material such as rubber closes the tool holes 40 and 40 on the outer peripheral surface of the small diameter portion 32b of the cover 32. Mated. The cushion ring 35 is provided with an interference with the outer peripheral surface of the small-diameter portion 32b at the inner diameter thereof, so that the cushion ring 35 is in close contact with the outer peripheral surface of the small-diameter portion 32b in a water-tight manner over the entire circumference. Can be closed watertight. A step 32c between the large-diameter portion 32a and the small-diameter portion 32b of the cover 32 is formed on a seat surface that supports one end surface of the cushion ring 35.
[0031]
A cushion ring 36 is also fitted to the outer peripheral surface of a portion of the valve housing 2 exposed from the front end face of the cover 32, and this is supported by the front end face of the cover 32.
[0032]
As shown in FIG. 1, the fuel injection valve I is attached to a throttle body B which forms a part of an intake system of the engine.
[0033]
That is, on one side wall of the throttle body B of the engine, an injection valve receiving hole 43 that opens obliquely toward the downstream side of the intake passage 42 downstream of the throttle valve 41, and an annular concave portion 44 that continues to the rear end are provided. The valve seat member 3 of the fuel injection valve I is inserted into the injection valve receiving hole 43, and the cushion ring 36 is inserted into the annular concave portion 44.
[0034]
A bracket 46 supporting a fuel supply pipe 45 for guiding the fuel discharged from the fuel pump is fixed to one side wall of the throttle body B with a bolt 48. The fuel supply pipe 45 is formed integrally with a joint cylinder 47 on one side, and the joint cylinder 47 is fitted to the rear end of the small diameter portion 32b of the cover 32 of the fuel injection valve I via a seal member 37. At the same time, the cushion ring 35 is arranged to be pressed against the seat surface 32c, that is, the throttle body B side by the flange portion 47a at the front end of the joint cylinder 47. Thus, the fuel injection valve I is elastically supported between the throttle body B and the fuel supply pipe 45 via the front and rear cushion rings 35 and 36. At this time, the flange portion 47a and the seat surface 32c are in close contact with the respective end surfaces of the cushion ring 35 in a watertight manner over the entire circumference, whereby the tool holes 40, 40 are also shut off from the outside in a watertight manner.
[0035]
Next, the operation of this embodiment will be described.
[0036]
When the coil 30 is energized by energization, the magnetic flux generated by it runs through the fixed core 5, the coil housing 31, the magnetic cylinder 4 and the movable core 12 sequentially, and the movable core 12 of the valve assembly V sets the valve spring 22 by the magnetic force. The valve core 18 is separated from the valve seat 8 by being sucked by the fixed core 5 against the load, so that the valve hole 7 is opened, and the high-pressure fuel in the valve seat member 3 exits the valve hole 7 and the fuel is injected. The fuel is injected from the hole 11 toward the downstream side of the intake passage 42 of the throttle body B.
[0037]
At this time, the stopper element 14 fitted and fixed to the movable core 12 of the valve assembly V comes into contact with the suction surface 5a of the fixed core 5, so that the valve opening limit of the valve body 18 is defined, and the suction of the movable core 12 is performed. The surface 12a faces the suction surface 5a of the fixed core 5 with an air gap g therebetween, and direct contact with the fixed core 5 is avoided. In particular, by controlling the dimension of the amount of protrusion of the stopper element 14 from the suction surface 12a of the movable core 12, the air gap g can be accurately and easily obtained, and the stopper element 14 is non-magnetic. When the coil 30 is demagnetized, the residual magnetism between the cores 5 and 12 disappears quickly, and the valve closing response of the valve element 18 can be improved.
[0038]
During the opening and closing operation of the valve assembly V, the pair of front and rear journals 17a, 17a on the valve rod 17 slides on the inner peripheral surface of the valve seat member 3 so that the valve assembly V is always kept in a proper posture without falling down. Therefore, the fuel injection characteristics can be stabilized.
[0039]
Further, since the first to third horizontal holes 20a to 20c communicating with the vertical holes 19 are opened on the outer peripheral surface of the valve assembly V, the fuel flowing into the vertical holes 19 is supplied to the first to third horizontal holes. The sliding surfaces of the journals 17a, 17a and the gap between the movable core 12 and the magnetic cylinder 4 are supplied to the sliding surfaces of the journals 17a, 17a through the sliding surfaces 20a to 20c. The magnetic cylinder 4 can be effectively cooled, and the responsiveness and wear resistance of the valve assembly V can be improved.
[0040]
Further, the second horizontal hole 20b crossing the movable core 12 can suppress generation of an eddy current in the movable core 12 when exciting and demagnetizing the coil 30, and can prevent heating of the movable core 12 due to the eddy current.
[0041]
Further, the deep vertical hole 19 extending to the vicinity of the spherical surface of the hemispherical valve portion 16, together with the first to third horizontal holes 20a to 20c, not only serves as a fuel passage, but also serves to remove the extravagance of the valve assembly V. This contributes to the weight reduction of the valve assembly V and, consequently, the improvement of responsiveness.
[0042]
Incidentally, in such an electromagnetic fuel injection valve I, when the coupler 34 and the cover 32 are molded with synthetic resin, the synthetic resin is injected into the coil housing 31 from the molded portion of the coupler 34 through the notch 31a of the coil housing 31. The filler can be smoothly filled, and at the same time, can be filled from the molded portion of the coupler 34 to the molded portion of the cover 32, thereby forming the coupler 34 and the cover 32 integrally and embedding the coil 30 with a synthetic resin. Can be performed reliably.
[0043]
In addition, since the flange-shaped yoke 5b is press-fitted into the coil housing 31 as a disk without a notch, a sufficiently wide magnetic path is secured between the yoke 5b and the coil housing 31 even if the yoke 5b is formed thin. Therefore, the thickness of the yoke can be reduced.
[0044]
Further, by using one side of the coil housing 31 for the installation space of the coupler 34, it is possible to suppress an increase in the axial length of the electromagnetic fuel injection valve I due to the coupler 34, and to reduce the thickness of the yoke 5b. In addition, the size of the electromagnetic fuel injection valve I can be greatly reduced.
[0045]
The present invention is not limited to the above embodiment, and various design changes can be made without departing from the gist of the present invention.
[0046]
【The invention's effect】
As described above, according to the present invention, the valve housing, the fixed core connected to the valve housing via the non-magnetic cylinder, and the coil disposed on the outer periphery of the fixed core are housed, and one end of the valve is housed. A valve body is composed of a coil housing connected to the outer periphery of the housing and a flange-shaped yoke formed integrally with the fixed core and connected to the other end of the coil housing, and is filled in the coil housing. In addition, a cover covering the outer periphery of the valve body and a coupler holding a connection terminal connected to the coil are integrally molded of synthetic resin. The other end is formed in a disk shape so as to be connected to the entire circumference thereof, and the coupler is disposed so as to protrude to one side of the coil housing. When the coupler and the cover are molded with a synthetic resin, an axial cutout for allowing the synthetic resin to flow into the coil housing is provided toward the coupler, so that the coupler and the cover are molded with the synthetic resin. During molding, the synthetic resin can be smoothly filled into the coil housing from the molded part of the coupler through the cutout part of the coil housing, and at the same time, can be filled from the molded part of the coupler to the molded part of the cover. Accordingly, the coil and the covering can be integrally molded and the coil can be securely embedded with the synthetic resin. Moreover, since the flange-shaped yoke is connected to the coil housing as a disk having no notch, a sufficiently wide magnetic path can be secured between the yoke and the coil housing even if the yoke is formed thin. Therefore, the yoke can be made thinner. Further, by disposing the coupler on one side of the coil housing, an increase in the axial length of the electromagnetic fuel injection valve due to the coupler can be suppressed. Can be made compact.
[Brief description of the drawings]
1 is a longitudinal sectional view showing an electromagnetic fuel injection valve according to the present invention mounted on a throttle body. FIG. 2 is an enlarged longitudinal sectional view of the fuel injection valve. FIG. 3 is a line 3-3 in FIG. FIG. 4 is a cross-sectional view corresponding to FIG. 3, showing a procedure for fixing a retainer pipe. FIG. 6 is a perspective view of a coil housing.
I ... Electromagnetic fuel injection valve 1 ... Valve body 2 ... Valve housing 5 ... Fixed core 6 ... Non-magnetic cylinder 30 ... Coil 31 Coil housing 31a Notch 32 Cover 33 Connection terminal 34 Coupler

Claims

A valve housing (2), a fixed core (5) connected to the valve housing (2) via a non-magnetic cylinder (6), and a coil (30) disposed on the outer periphery of the fixed core (5). And a coil housing (31) having one end connected to the outer periphery of the valve housing (2) and one end formed integrally with the fixed core (5) and connected to the other end of the coil housing (31). The flange-shaped yoke (5b) forms a valve body (1), which is filled in the coil housing (31) and covers the outer periphery of the valve body (1). An electromagnetic fuel injection valve, in which a coupler (34) holding a connection terminal (33) connected to the connection terminal (30) is molded integrally with a synthetic resin,
The yoke (5b) is formed in a disk shape so as to be connected to the other end of the coil housing (31) over the entire circumference thereof, and the coupler (34) is placed on one side of the coil housing (31). The coil housing (31) is arranged so as to protrude, and a shaft through which the synthetic resin flows into the coil housing (31) when the coupler (34) and the cover (32) are molded with synthetic resin. An electromagnetic fuel injection valve characterized in that a notch (31a) in the direction is provided toward the coupler (34).