JP3947369B2

JP3947369B2 - Fuel injection valve

Info

Publication number: JP3947369B2
Application number: JP2001163414A
Authority: JP
Inventors: 信章小林; 秀夫加藤; 弘岡田
Original assignee: Hitachi Ltd
Current assignee: Hitachi Ltd
Priority date: 2001-05-30
Filing date: 2001-05-30
Publication date: 2007-07-18
Anticipated expiration: 2021-05-30
Also published as: JP2002357167A

Description

【０００１】
【発明の属する技術分野】
本発明は、例えば自動車用エンジン等に燃料を噴射するのに好適に用いられる燃料噴射弁に関する。
【０００２】
【従来の技術】
一般に、例えば自動車用エンジン等に用いられる燃料噴射弁は、弁ケーシング内に弁体が変位可能に挿通されている。そして、噴射弁の作動時には、電磁コイル等のアクチュエータが作動することによって弁体が開弁すると、弁ケーシング内の燃料通路に供給される燃料がエンジンの吸気管等に向けて噴射されるものである（例えばドイツ特許公開ＤＥ１９５４７４０６Ａ１号公報、特開２０００−８９９０号公報等）。
【０００３】
この種の従来技術による燃料噴射弁は、弁ケーシングの本体部分が磁性筒体により構成されている。そして、磁性筒体は、例えば電磁ステンレス鋼（ＳＵＳ４３０）等を用いた細長い金属パイプからなり、絞り加工等の手段によって加工成形されている。この場合、磁性筒体は、噴射弁を軽量化するために、強度的に許される範囲内で可能な限り薄肉化されていることが多い。
【０００４】
そして、磁性筒体の先端側には、例えば金属製のホルダ等を介して筒状の弁座部材が設けられ、該弁座部材には、磁性筒体内に挿通された弁体が離着座する弁座が設けられている。また、磁性筒体の基端側内周には、電磁コイルの作動時に弁体を磁気的に吸着して開弁させるコア部材が設けられている。また、磁性筒体の外周側には電磁コイルと樹脂カバーとが設けられている。
【０００５】
【発明が解決しようとする課題】
ところで、上述した従来技術では、例えばＳＵＳ４３０等の一般的に広く知られている電磁ステンレス鋼を細長いパイプ状に加工成形することにより、磁性筒体を形成する構成としている。この場合、磁性筒体の形成時には、絞り加工等の手段によって金属材料をパイプ状に塑性変形させつつ、その全長を薄肉に形成する必要がある。また、噴射弁の設計時には、例えば弁座部材、電磁アクチュエータ、コア部材等からなる各部品の取付部位や位置決め部位を磁性筒体に設けるため、磁性筒体を段付き筒状に形成したい場合もある。
【０００６】
しかし、磁性筒体の形成時には、その肉厚を絞り加工等の手段によって薄肉化したり、磁性筒体を複雑な段付き形状等に成形しようとすると、金属材料が薄肉で複雑な形状に追従できないことがあり、磁性筒体には成形工程の途中で亀裂、破断等の損傷が生じ易くなる。
【０００７】
このため、従来技術では、磁性筒体の歩留まりが低下し、噴射弁を効率よく製造できないばかりでなく、成形時の無理な変形等によって磁性筒体の強度にばらつきが生じる虞れがあり、信頼性が低下するという問題がある。
【０００８】
本発明は上述した従来技術の問題に鑑みなされたもので、本発明の目的は、例えば磁性筒体を薄肉で複雑な形状に成形する場合でも、その加工成形を容易に行うことができ、磁性筒体の強度を安定的に保持できると共に、生産性、信頼性を向上できるようにした燃料噴射弁を提供することにある。
【０００９】
【課題を解決するための手段】
上述した課題を解決するために本発明は、磁性材料により筒状に形成され内部が燃料通路となった磁性筒体と、該磁性筒体に設けられ噴射口を囲んで弁座が形成された弁座部材と、前記磁性筒体内に変位可能に設けられ電磁アクチュエータが作動することにより該弁座部材の弁座に離着座する弁体とからなる燃料噴射弁に適用される。
【００１０】
そして、請求項１の発明が採用する構成の特徴は、磁性筒体は、その軸方向一側に位置する弁座部材取付部と、該弁座部材取付部の軸方向他側に段部を介して一体形成され該弁座部材取付部よりも拡径したアクチュエータ取付部と、該アクチュエータ取付部の軸方向他側に段部を介して一体形成され該アクチュエータ取付部よりも拡径した樹脂カバー形成部とを含んだ段付き状の筒体として、チタンを含有したフェライト系ステンレス材料を用いて形成し、前記磁性筒体の弁座部材取付部内には弁座部材を嵌合して設け、前記アクチュエータ取付部の外周側には電磁アクチュエータを設け、前記樹脂カバー形成部の外周側には、電磁アクチュエータに給電するコネクタが一体に樹脂成形された樹脂カバーを設ける構成としたことにある。
【００１１】
このように構成することにより、チタンを含有したフェライト系ステンレス材料を用いて、軸方向一側に位置する弁座部材取付部と、該弁座部材取付部の軸方向他側に拡径して一体形成されたアクチュエータ取付部と、該アクチュエータ取付部の軸方向他側に拡径して一体形成された樹脂カバー形成部とを含んだ段付き状の磁性筒体を容易に加工成形することができる。そして、該磁性筒体の弁座部材取付部には、例えば弁座部材の取付部位を、アクチュエータ取付部には電磁アクチュエータの取付部位を形成でき、樹脂カバー形成部には、コネクタが一体に樹脂成形された樹脂カバーを設けることができる。しかも、フェライト系ステンレス材料にチタンを含有させることによって、磁性筒体の強度、耐食性を確保しつつ、その柔軟性（伸び）を高めることができる。従って、磁性筒体の形成時には、例えばプレス加工、ロール加工等の手段によりステンレス材料を安定的に塑性変形させることができ、その加工性を向上させることができる。
【００１２】
また、請求項２の発明によると、磁性筒体のフェライト系ステンレス材料は前記チタンを０．２〜０．６重量％含有する構成としている。
【００１３】
これにより、磁性筒体となるステンレス材料の硬度を許容範囲内で適度に柔らかく形成でき、またステンレス材料の伸びを増大させることができるので、複雑な形状の磁性筒体であっても、その加工成形を容易に行うことができる。
【００１４】
また、請求項３の発明によると、磁性筒体のフェライト系ステンレス材料は炭素を０．０１〜０．１２重量％含有し、該炭素の含有率よりも前記チタンの含有率が大きくなるように形成する構成としている。
【００１５】
これにより、ステンレス材料中に含まれる炭素の含有量を小さく抑えてフェライト系ステンレス材料を形成でき、その耐食性を向上させることができる。また、炭素よりも多くのチタンを含有させることによってステンレス材料に安定した柔軟性を与えることができる。
【００１８】
また、請求項４の発明によると、磁性筒体は、チタンを含有したフェライト系ステンレス材料からなる金属板を、深絞り加工手段により筒状に塑性変形させて形成する構成としている。
【００１９】
これにより、例えばパンチ等の治具によって薄肉なステンレス鋼板を板厚方向へと筒状に塑性変形させ、磁性筒体を容易に形成することができる。
【００２０】
また、請求項５の発明によると、磁性筒体内には前記弁体と軸方向の隙間を挟んで対面するコア部材を設け、前記磁性筒体には前記隙間が形成される位置で前記磁性筒体の磁気抵抗を増大させる薄肉部を設ける構成としている。
【００２１】
これにより、例えばプレス加工、研削加工等の手段により磁性筒体の長さ方向途中部位に薄肉部を形成でき、この薄肉部は、磁性筒体のうち弁体が配置された部位とコア部材が配置された部位との間を磁気的に遮断することができる。従って、電磁アクチュエータによる磁界が弁体とコア部材との間の隙間を通過するときには、この磁界が磁性筒体によって短絡されるのを防止することができる。
【００２２】
【発明の実施の形態】
以下、本発明の実施の形態による燃料噴射弁を、添付図面を参照して詳細に説明する。
【００２３】
ここで、図１ないし図８は本発明による第１の実施の形態を示し、本実施の形態では、自動車用エンジンに用いられる燃料噴射弁を例に挙げて述べる。
【００２４】
１は燃料噴射弁の外殻をなす弁ケーシングで、該弁ケーシング１は、後述の磁性筒体２、磁性カバー１２、樹脂カバー１４等を含んで構成されている。
【００２５】
２は弁ケーシング１の本体部分を構成する段付き筒状の磁性筒体で、該磁性筒体２は、後述の如くチタンを含有したフェライト系ステンレス材料等からなり、例えば深絞り加工等のプレス加工手段により図１、図７に示す如く段付き形状をなす薄肉な金属パイプとして形成され、例えば０．１〜０．９ｍｍ程度の予め定められた肉厚寸法を有している。
【００２６】
そして、磁性筒体２は、その軸方向一側（先端側）に位置する弁座部材取付部２Ａと、該弁座部材取付部２Ａの軸方向他側（基端側）に段部２Ｂ1を介して形成され、弁座部材取付部２Ａよりも拡径したアクチュエータ取付部２Ｂと、該アクチュエータ取付部２Ｂの基端側に段部２Ｃ1を介して形成され、アクチュエータ取付部２Ｂよりも拡径した樹脂カバー形成部２Ｃとを含んで構成されている。
【００２７】
また、アクチュエータ取付部２Ｂの長さ方向途中部位には、後述の弁体７とコア筒８との間の隙間Ｓを取囲んで環状の薄肉部２Ｄが設けられ、該薄肉部２Ｄは、アクチュエータ取付部２Ｂを、後述の弁体７が変位可能に収容された弁体側筒部２Ｂ2とコア筒８が挿嵌されたコア部材側筒部２Ｂ3とに分割している。そして、薄肉部２Ｄは、弁体側筒部２Ｂ2とコア部材側筒部２Ｂ3との間の磁気抵抗を増大させて両者間を磁気的に遮断し、これらの筒部２Ｂ2，２Ｂ3間で後述の磁界Ｈが短絡されるのを防止している。
【００２８】
ここで、磁性筒体２を構成するステンレス材料について述べると、このステンレス材料は、例えば炭素を０．０１〜０．１２重量％（好ましくは０．０１〜０．０５重量％）含有したフェライト系ステンレス材料として形成されると共に、クロムを１６重量％以上、ニッケルを０．０８重量％以上、チタンを０．２〜０．６重量％含有し、チタンの含有率は炭素の含有率よりも大きく形成されている。
【００２９】
この場合、本実施の形態では、下記表１の実施例１，２または３に示す如く、例えばＳＵＳ４３０Ｍ２、ＳＵＳ４３０Ｍ３、ＳＵＳ４３０ＷＤ等のフェライト系ステンレス材料を用いて磁性筒体２を形成している。
【００３０】
【表１】

【００３１】
そして、本実施の形態では、フェライト系ステンレス材料を用いて磁性筒体２の強度、耐食性等を確保すると共に、後述の表２に示す如くチタンによって磁性筒体２の柔軟性（伸び等）を高め、深絞り加工等を行うときの加工性を向上させているものである。
【００３２】
３は磁性筒体２内に設けられた燃料通路で、該燃料通路３は、図１に示す如く磁性筒体２の樹脂カバー形成部２Ｃから弁座部材５の位置まで軸方向に延びている。また、樹脂カバー形成部２Ｃ内には、磁性筒体２の基端側から燃料通路３内に供給される燃料を濾過する燃料フィルタ４が設けられている。
【００３３】
５は磁性筒体２の弁座部材取付部２Ａ内に嵌合して設けられた筒状の弁座部材で、該弁座部材５には、図２に示す如く、燃料通路３内の燃料を外部に噴射する噴射口５Ａと、該噴射口５Ａを取囲んで形成された略円錐状の弁座５Ｂとが設けられている。そして、弁座部材５は、その外周側が弁座部材取付部２Ａと全周に亘って溶接されている。また、弁座部材５の先端面には、複数のノズル孔６Ａが穿設されたノズルプレート６が噴射口５Ａを覆う位置に固着されている。
【００３４】
７は磁性筒体２の弁体側筒部２Ｂ2内に変位可能に収容された弁体で、該弁体７は、図２に示す如く、軸方向に延びた筒状の弁軸７Ａと、該弁軸７Ａの先端側に固着され、弁座部材５の弁座５Ｂに離着座する球状の弁部７Ｂと、例えば磁性金属材料等により弁軸７Ａの基端側に形成され、磁性筒体２内に摺動可能に挿嵌された筒状の吸着部７Ｃとにより構成されている。
【００３５】
そして、弁体７の閉弁時には、その弁部７Ｂが後述する付勢ばね９のばね力によって弁座部材５の弁座５Ｂに着座した状態に保持され、このとき吸着部７Ｃの基端面とコア筒８とは、軸方向の隙間Ｓを挟んで対面している。また、後述の電磁コイル１１に給電したときには、電磁コイル１１により図２中の磁界Ｈが形成されると、弁体７は、その吸着部７Ｃがコア筒８によって磁気的に吸着され、付勢ばね９のばね力に抗して開弁するものである。
【００３６】
８は例えば磁性金属材料等により筒状に形成されたコア部材としてのコア筒で、該コア筒８は、磁性筒体２のコア部材側筒部２Ｂ3内に圧入等の手段により挿嵌され、磁性筒体２に固定されている。
【００３７】
９は磁性筒体２内に設けられた付勢ばねで、該付勢ばね９は、コア筒８の内周側に圧入等の手段により固定された筒状のばね受１０と弁体７との間に圧縮状態で配設され、弁体７を閉弁方向に常時付勢している。
【００３８】
１１は磁性筒体２のアクチュエータ取付部２Ｂの外周側に挿嵌して設けられた電磁アクチュエータとしての電磁コイルで、該電磁コイル１１は、後述のコネクタ１５を用いて給電されることにより磁界Ｈを発生し、弁体７を付勢ばね９のばね力に抗して開弁させるものである。
【００３９】
１２は例えば磁性金属材料等により段付き筒状に形成された磁性カバーで、該磁性カバー１２は、図２、図３に示す如く、電磁コイル１１の外周側に設けられた大径筒部１２Ａと、該大径筒部１２Ａの先端側に一体に形成され、磁性筒体２の弁体側筒部２Ｂ2の外周側に嵌合、固着された小径筒部１２Ｂとによって構成されている。また、大径筒部１２Ａと磁性筒体２のコア部材側筒部２Ｂ3との間には、磁性材料等により略Ｃ字状に形成された連結コア１３が挿嵌されている。
【００４０】
これにより、磁性カバー１２は、小径筒部１２Ｂと連結コア１３とによって電磁コイル１１を挟んだ軸方向の両側で磁性筒体２と磁気的に連結されている。そして、電磁コイル１１の作動時には、磁性筒体２の弁体側筒部２Ｂ2とコア部材側筒部２Ｂ3とが薄肉部２Ｄによって磁気的にほぼ遮断されているため、これらの筒部２Ｂ2，２Ｂ3と、弁体７の吸着部７Ｃ、コア筒８、磁性カバー１２、連結コア１３とに沿って磁界Ｈを安定的に形成でき、弁体７をコア筒８により磁気的に吸着して開弁させることができる。
【００４１】
１４は例えば射出成形等の手段を用いて磁性筒体２の樹脂カバー形成部２Ｃの外周側に設けられた樹脂カバーで、該樹脂カバー１４には、図１に示す如く、電磁コイル１１に給電するコネクタ１５が一体に樹脂成形されている。
【００４２】
本実施の形態による燃料噴射弁は上述の如き構成を有するもので、次にその作動について説明する。
【００４３】
まず、噴射弁の作動時には、コネクタ１５から電磁コイル１１に給電すると、図２に示す如く磁界Ｈが形成され、この磁界Ｈは弁体７の吸着部７Ｃとコア筒８との間の隙間Ｓを通過するようになる。この結果、弁体７はコア筒８によって磁気的に吸着され、付勢ばね９に抗して軸方向に変位するようになり、弁部７Ｂが弁座部材５の弁座５Ｂから離座して開弁する。これにより、燃料通路３内に供給される燃料は、噴射口５Ａからエンジンの吸気管等に向けて噴射される。
【００４４】
また、噴射弁の組立作業について述べると、まず図４ないし図７に示す磁性筒体形成工程では、例えば３段階の深絞り加工を金属板１６に施すことにより、磁性筒体２を形成する。
【００４５】
そして、この工程では、図４に示す如く、まず磁性筒体２となるフェライト系ステンレス材料により形成された薄肉な金属板１６を用意する。次に、この金属板１６を、図５に示す如くプレス加工装置１７のダイ１７Ａと押え板１７Ｂとの間に配置し、所定の外径寸法を有するパンチ１７Ｃによって金属板１６を板厚方向へと筒状に塑性変形させることにより、金属板１６に１回目の深絞り加工を施し、例えば磁性筒体２の弁座部材取付部２Ａとなる小径部位１６Ａを形成する。
【００４６】
次に、図６に示す如く磁性筒体２のアクチュエータ取付部２Ｂに対応するダイ１７Ｄ、押え板１７Ｅ、パンチ１７Ｆを用いて２回目の深絞り加工を施すことにより、小径部位１６Ａの基端側にアクチュエータ取付部２Ｂとなる中間径部位１６Ｂを形成し、さらに樹脂カバー形成部２Ｃに対応するパンチ等を用いて３回目の深絞り加工を施すことにより、中間径部位１６Ｂの基端側にアクチュエータ取付部２Ｂとなる大径部位を形成する。そして、これらの筒状部位を金属板１６から切離し、例えば切削加工、プレス加工等の手段によって薄肉部２Ｄを設けることにより、図７に示す如く磁性筒体２を形成する。
【００４７】
この場合、磁性筒体２となる金属板１６は、前記表１の実施例１〜３に示す如く、チタンを含有するフェライト系ステンレス材料により形成されているので、例えば下記の表２に示す如く、比較例として掲げたＳＵＳ４３０によるステンレス材料と比較し、金属板１６の伸び率を高め、その硬さ（下記表２では、硬さとしてビッカース硬度の測定値を例示）を適度に柔らかく形成することができる。
【００４８】
【表２】

【００４９】
これにより、磁性筒体２の加工成形時には、金属板１６をプレス加工装置１７によって柔軟に塑性変形させることができ、段部２Ｂ1，２Ｃ1等を有する薄肉な磁性筒体２をプレス成形する場合でも、成形工程の途中で無理な変形等により金属板１６に亀裂、破断等の損傷が生じるのを防止することができる。
【００５０】
次に、図８に示す部品組付工程では、まず磁性筒体２の外周側に電磁コイル１１、磁性カバー１２および連結コア１３を組付け、これらの外周側に樹脂カバー１４を射出成形した後に、磁性筒体２に対して弁体７、コア筒８、付勢ばね９、ばね受１０等を組付けることにより、噴射弁を組立てることができる。
【００５１】
かくして、本実施の形態によれば、磁性筒体２は、チタンを含有したフェライト系ステンレス材料により形成する構成としたので、磁性筒体２の強度、耐食性を確保しつつ、その柔軟性を高めることができる。これにより、磁性筒体２の形成時には、例えば深絞り加工等の手段により金属板１６を安定的に塑性変形させることができ、その加工性を向上させることができる。
【００５２】
従って、薄肉で細長い段付き筒状の磁性筒体２を形成する場合でも、例えば深絞り加工等の手段により金属板１６を用いて磁性筒体２を容易に加工成形でき、その弁座部材取付部２Ａ、アクチュエータ取付部２Ｂ、樹脂カバー形成部２Ｃ等には、高い寸法精度と安定した強度とを与えることができる。これにより、磁性筒体２の歩留まりを高め、噴射弁の生産性、信頼性を向上させることができる。
【００５３】
この場合、磁性筒体２に含まれるチタンの含有率は例えば０．２〜０．６重量％とし、炭素の含有率よりも大きくなるように形成したので、チタンの含有率に応じてステンレス材料の硬度を許容範囲内で適度に柔らかく形成でき、その伸びを十分に増大させることができる。また、炭素の含有率を小さく抑制できるから、磁性筒体２の耐食性を向上させることができる。
【００５４】
また、磁性筒体２となるフェライト系ステンレス材料は、前記表１中の実施例１〜３に示す如く、炭素の含有率を０．０５重量％以下の微量に抑えているので、耐食性をより向上させることができる。特に、実施例２のステンレス材料においては、例えば０．３重量％以上のモリブデンを含有しているので、さらに耐食性を高めて噴射弁の寿命を延ばすことができる。
【００５５】
一方、磁性筒体２を金属パイプ等により一体に形成し、その途中部位に薄肉部２Ｄを設けたので、噴射弁の組立時には、例えばプレス加工、切削加工等の機械加工処理を金属パイプに施すだけで、磁気的な遮断部位となる薄肉部２Ｄが設けられた磁性筒体２を容易に形成でき、噴射弁の部品点数を削減して構造を簡略化することができる。
【００５６】
次に、図９ないし図１１は本発明による第２の実施の形態を示し、本実施の形態の特徴は、金属板を筒状に湾曲させて溶接することにより磁性筒体を構成したことにある。
【００５７】
２１は第１の実施の形態の磁性筒体２に代えて用いられる磁性筒体で、該磁性筒体２１は、第１の実施の形態とほぼ同様に、チタンを含有したフェライト系ステンレス材料からなり、弁座部材取付部２１Ａ、アクチュエータ取付部２１Ｂ、樹脂カバー形成部２１Ｃ、薄肉部２１Ｄ、段部２１Ｂ1，２１Ｃ1、筒部２１Ｂ2，２１Ｂ3を含んで構成されている。しかし、磁性筒体２１は、筒状に湾曲させた金属板からなり、その周方向の一箇所には、例えばシーム溶接等の溶接手段により磁性筒体２１の全長に亘って延びた溶接部２２が設けられている。
【００５８】
この場合、磁性筒体２１の形成時には、図１０に示す如く、まず金属板をロール加工等の手段により筒状に湾曲させ、その両端側を衝合してシーム溶接等の溶接手段を施すことにより、円筒体２３を形成する。そして、例えばロール２４、ロッド２５等を用いて円筒体２３に径方向外側から絞り加工を施すことにより、円筒体２３を段付き筒状に加工成形し、その長さ方向の各部位を磁性筒体２１の弁座部材取付部２１Ａ、アクチュエータ取付部２１Ｂ、樹脂カバー形成部２１Ｃとして形成する。
【００５９】
かくして、このように構成される本実施の形態でも、第１の実施の形態とほぼ同様の作用効果を得ることができる。そして、特に本実施の形態では、金属板を筒状に湾曲させてシーム溶接、絞り加工等の手段を施すだけで、細長い段付き筒状の磁性筒体２１を容易に加工成形することができる。
【００６０】
なお、前記各実施の形態では、磁性筒体２，２１にチタン入りのフェライト系ステンレス材料を用いる構成としたが、本発明はこれに限らず、例えばチタン入りのフェライト系ステンレス材料に０．３重量％以上の銅（Ｃｕ）、０．３重量％以上のニオブ（Ｎｂ）、またはこれら両方の元素を含有させ、磁性筒体の耐食性や強度をより高める構成としてもよい。
【００６１】
また、前記各実施の形態では、例えばＳＵＳ４３０Ｍ２、ＳＵＳ４３０Ｍ３、ＳＵＳ４３０ＷＤ等のフェライト系ステンレス材料を用いる構成としたが、本発明の磁性筒体に含まれる元素の種類、含有率の具体値等は、これらの実施例に限るものではなく、本発明は、炭素の含有率を抑えてチタンを含有させた各種のフェライト系ステンレス材料に適用されるのは勿論である。
【００６２】
【発明の効果】
以上詳述した通り、請求項１の発明によれば、磁性筒体は、その軸方向一側に位置する弁座部材取付部と、該弁座部材取付部の軸方向他側に段部を介して一体形成され該弁座部材取付部よりも拡径したアクチュエータ取付部と、該アクチュエータ取付部の軸方向他側に段部を介して一体形成され該アクチュエータ取付部よりも拡径した樹脂カバー形成部とを含んだ段付き状の筒体として、チタンを含有したフェライト系ステンレス材料を用いて形成し、前記磁性筒体の弁座部材取付部内には弁座部材を嵌合して設け、前記アクチュエータ取付部の外周側には電磁アクチュエータを設け、前記樹脂カバー形成部の外周側には、電磁アクチュエータに給電するコネクタが一体に樹脂成形された樹脂カバーを設ける構成としているので、チタンを含有したフェライト系ステンレス材料を用いて、弁座部材取付部、アクチュエータ取付部および樹脂カバー形成部を含んだ段付き状の磁性筒体を容易に加工成形することができる。そして、該磁性筒体の弁座部材取付部には、例えば弁座部材の取付部位を、アクチュエータ取付部には電磁アクチュエータの取付部位を形成でき、樹脂カバー形成部には、コネクタが一体に樹脂成形された樹脂カバーを設けることができる。しかも、チタンを含有したフェライト系ステンレス材料を用いることにより、磁性筒体の強度、耐食性を確保しつつ、その柔軟性を高めることができる。これにより、例えば薄肉で細長い磁性筒体を形成する場合でも、ステンレス材料を安定的に塑性変形させることができ、その加工性を高めることができる。従って、磁性筒体の各部位に高い寸法精度と安定した強度とを与えることができ、磁性筒体の歩留まりを高め、噴射弁の生産性、信頼性を向上させることができる。
【００６３】
また、請求項２の発明によれば、磁性筒体のフェライト系ステンレス材料はチタンを０．２〜０．６重量％含有する構成としたので、チタンの含有率に応じてステンレス材料の硬度を許容範囲内で適度に柔らかく形成でき、その伸びを十分に増大させることができる。これにより、複雑な形状の磁性筒体であっても、その加工成形を容易に行うことができる。
【００６４】
また、請求項３の発明によれば、磁性筒体のフェライト系ステンレス材料は炭素を０．０１〜０．１２重量％含有し、該炭素の含有率よりも前記チタンの含有率が大きくなるように形成する構成としたので、ステンレス材料中に含まれる炭素の含有量を小さく抑えてフェライト系ステンレス材料を形成でき、その耐食性を向上させることができる。また、炭素よりも多くのチタンを含有させることによってステンレス材料に安定した柔軟性を与えることができる。
【００６６】
また、請求項４の発明によるば、磁性筒体は、チタンを含有したフェライト系ステンレス材料からなる金属板を、深絞り加工手段により筒状に塑性変形させて形成する構成としたので、例えば薄肉で細長い磁性筒体を形成する場合でも、パンチ等の治具によってチタン入りのフェライト系ステンレス材料を板厚方向へと容易に塑性変形させることができ、その加工成形を容易に行うことができる。
【００６７】
また、請求項５の発明によれば、磁性筒体には、弁体とコア部材との間の隙間の位置で磁性筒体の磁気抵抗を増大させる薄肉部を設ける構成としたので、例えばプレス加工、切削加工等の機械加工処理を磁性筒体に施すだけで、磁気的な遮断部位となる薄肉部を容易に形成でき、電磁アクチュエータの作動時には、薄肉部によって弁体とコア部材との間に磁界を安定的に形成することができる。
【図面の簡単な説明】
【図１】本発明の第１の実施の形態による燃料噴射弁を示す縦断面図である。
【図２】燃料噴射弁の先端側を示す部分拡大断面図である。
【図３】図１中の矢示III−III方向からみた燃料噴射弁の拡大断面図である。
【図４】磁性筒体となるチタン入りのフェライト系ステンレス材料により形成された金属板を示す部分拡大断面図である。
【図５】金属板に１回目の深絞り加工を施すことにより磁性筒体の弁座部材取付部となる部位を形成する状態を示す部分拡大断面図である。
【図６】金属板に２回目の深絞り加工を施すことにより磁性筒体のアクチュエータ取付部となる部位を形成する状態を示す部分拡大断面図である。
【図７】金属板に３回目の深絞り加工等を施して形成された磁性筒体を単体で示す縦断面図である。
【図８】磁性筒体に各部品を取付けて噴射弁を組立てる状態を示す縦断面図である。
【図９】本発明の第２の実施の形態による燃料噴射弁の磁性筒体を示す縦断面図である。
【図１０】金属板により磁性筒体となる円筒体を形成した状態を示す部分拡大断面図である。
【図１１】円筒体に絞り加工を施している状態を示す部分拡大断面図である。
【符号の説明】
１弁ケーシング
２，２１磁性筒体
２Ａ，２１Ａ弁座部材取付部
２Ｂ，２１Ｂアクチュエータ取付部
２Ｃ，２１Ｃ樹脂カバー形成部
２Ｄ，２１Ｄ薄肉部
３燃料通路
５弁座部材
５Ａ噴射口
５Ｂ弁座
７弁体
８コア筒（コア部材）
９付勢ばね
１１電磁コイル（電磁アクチュエータ）
１２磁性カバー
１３連結コア
１４樹脂カバー
１５コネクタ
Ｓ隙間[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel injection valve suitably used for injecting fuel into, for example, an automobile engine.
[0002]
[Prior art]
In general, for example, a fuel injection valve used for an automobile engine or the like is inserted into a valve casing so that a valve body can be displaced. When the injection valve is operated, when an actuator such as an electromagnetic coil is operated to open the valve body, the fuel supplied to the fuel passage in the valve casing is injected toward the intake pipe of the engine. There are (for example, German Patent Publication DE195547406A1, JP2000-8990A, etc.).
[0003]
In this type of conventional fuel injection valve, the main body portion of the valve casing is formed of a magnetic cylinder. The magnetic cylinder is made of an elongated metal pipe using, for example, electromagnetic stainless steel (SUS430) or the like, and is processed and formed by means such as drawing. In this case, in order to reduce the weight of the injection valve, the magnetic cylinder is often thinned as much as possible within the allowable range.
[0004]
A cylindrical valve seat member is provided on the front end side of the magnetic cylinder through, for example, a metal holder, and the valve element inserted into the magnetic cylinder is attached to and detached from the valve seat member. A valve seat is provided. In addition, a core member that magnetically attracts and opens the valve body when the electromagnetic coil is operated is provided on the inner periphery of the base end side of the magnetic cylinder. An electromagnetic coil and a resin cover are provided on the outer peripheral side of the magnetic cylinder.
[0005]
[Problems to be solved by the invention]
By the way, in the prior art mentioned above, it is set as the structure which forms a magnetic cylinder body by processing and forming generally-known electromagnetic stainless steel, such as SUS430, in the shape of an elongate pipe. In this case, at the time of forming the magnetic cylinder, it is necessary to form the entire length thinly while plastically deforming the metal material into a pipe shape by means such as drawing. In addition, when designing the injection valve, for example, the magnetic cylinder may be formed into a stepped cylinder because the attachment part and positioning part of each component including a valve seat member, an electromagnetic actuator, a core member, etc. are provided in the magnetic cylinder. is there.
[0006]
However, when forming the magnetic cylinder, if the thickness is reduced by means such as drawing or the magnetic cylinder is formed into a complicated stepped shape, the metal material is thin and cannot follow the complicated shape. In some cases, the magnetic cylinder is likely to be damaged such as cracks and fractures during the molding process.
[0007]
For this reason, in the prior art, the yield of the magnetic cylinder is reduced, and not only the injection valve cannot be manufactured efficiently, but also the strength of the magnetic cylinder may vary due to unreasonable deformation at the time of molding. There is a problem that the performance is lowered.
[0008]
The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to easily perform processing and molding even when the magnetic cylinder is molded into a thin and complicated shape, for example. An object of the present invention is to provide a fuel injection valve capable of stably maintaining the strength of a cylinder and improving productivity and reliability.
[0009]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention includes a magnetic cylinder that is formed in a cylindrical shape with a magnetic material and has a fuel passage inside, and a valve seat that is provided in the magnetic cylinder and surrounds an injection port. A valve seat member and an electromagnetic actuator that is displaceably provided in the magnetic cylinder body and is attached to and detached from the valve seat of the valve seat member seat The present invention is applied to a fuel injection valve comprising a valve body that
[0010]
The feature of the configuration adopted by the invention of claim 1 is that the magnetic cylinder is The valve seat member mounting portion located on one side in the axial direction and the actuator mounting portion formed integrally with the other side in the axial direction of the valve seat member mounting portion via a stepped portion and having a diameter larger than that of the valve seat member mounting portion. And a stepped cylindrical body including a resin cover forming portion integrally formed through a step portion on the other axial side of the actuator mounting portion and having a diameter larger than that of the actuator mounting portion, Using ferritic stainless steel containing titanium Forming and providing a valve seat member fitted in the valve seat member mounting portion of the magnetic cylinder, providing an electromagnetic actuator on the outer peripheral side of the actuator mounting portion, and on the outer peripheral side of the resin cover forming portion, Provide a resin cover in which the connector for supplying power to the electromagnetic actuator is integrally molded with resin Constitution When It is to have done.
[0011]
By configuring in this way, Using a ferritic stainless material containing titanium, a valve seat member mounting portion located on one side in the axial direction, and an actuator mounting portion integrally formed by expanding the diameter to the other side in the axial direction of the valve seat member mounting portion The stepped magnetic cylinder including the resin cover forming portion integrally formed by expanding the diameter to the other side in the axial direction of the actuator mounting portion can be easily processed and molded. For example, the valve seat member mounting portion of the magnetic cylinder can be formed with a valve seat member mounting portion, the actuator mounting portion with an electromagnetic actuator mounting portion, and the resin cover forming portion with a connector integrally formed with resin. A molded resin cover can be provided. Moreover, By including titanium in ferritic stainless steel , The flexibility (elongation) can be enhanced while ensuring the strength and corrosion resistance of the magnetic cylinder. Therefore, when the magnetic cylinder is formed, the stainless steel material can be stably plastically deformed by means such as press working and roll working, and the workability can be improved.
[0012]
According to a second aspect of the present invention, the ferritic stainless material of the magnetic cylinder contains 0.2 to 0.6% by weight of the titanium.
[0013]
As a result, the hardness of the stainless steel material that becomes the magnetic cylinder can be formed to be moderately soft within an allowable range, and the elongation of the stainless steel material can be increased, so even a magnetic cylinder having a complicated shape can be processed. Molding can be performed easily.
[0014]
According to the invention of claim 3, the ferritic stainless material of the magnetic cylinder contains 0.01 to 0.12% by weight of carbon so that the titanium content is larger than the carbon content. It is set as the structure to form.
[0015]
Thereby, the content of carbon contained in the stainless steel material can be suppressed to be small, and the ferritic stainless steel material can be formed, and the corrosion resistance can be improved. Moreover, the stable softness | flexibility can be given to a stainless steel material by containing more titanium than carbon.
[0018]

Claims

4 According to the invention, the magnetic cylinder is Made of ferritic stainless steel containing titanium Metal plate , It is configured to be formed by being plastically deformed into a cylindrical shape by deep drawing processing means.
[0019]
Thereby, for example, a thin stainless steel plate can be plastically deformed into a cylindrical shape in the thickness direction by a jig such as a punch, and a magnetic cylinder can be easily formed.
[0020]

Claims

5 According to the invention, the magnetic cylinder is provided with a core member facing the valve body with an axial gap therebetween, and the magnetic cylinder has a magnetic resistance at a position where the gap is formed. It is set as the structure which provides the thin part to increase.
[0021]
Thereby, for example, a thin portion can be formed in the middle portion of the magnetic cylinder in the length direction by means such as press working or grinding, and this thin portion is formed by the portion of the magnetic cylinder where the valve body is disposed and the core member. It is possible to magnetically block between the arranged portions. Accordingly, when the magnetic field generated by the electromagnetic actuator passes through the gap between the valve body and the core member, the magnetic field can be prevented from being short-circuited by the magnetic cylinder.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, fuel injection valves according to embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0023]
1 to 8 show a first embodiment according to the present invention. In this embodiment, a fuel injection valve used in an automobile engine will be described as an example.
[0024]
Reference numeral 1 denotes a valve casing that forms an outer shell of the fuel injection valve. The valve casing 1 includes a magnetic cylinder 2, a magnetic cover 12, a resin cover 14, and the like, which will be described later.
[0025]
Reference numeral 2 denotes a stepped cylindrical magnetic cylinder constituting the main part of the valve casing 1, and the magnetic cylinder 2 is made of a ferritic stainless steel material containing titanium as will be described later. It is formed as a thin metal pipe having a stepped shape as shown in FIGS. 1 and 7 by the processing means, and has a predetermined thickness dimension of about 0.1 to 0.9 mm, for example.
[0026]
The magnetic cylinder 2 has a valve seat member mounting portion 2A located on one axial side (tip side) and a step portion 2B1 on the other axial side (base end side) of the valve seat member mounting portion 2A. An actuator mounting portion 2B having a diameter larger than that of the valve seat member mounting portion 2A, and a stepped portion 2C1 formed on the base end side of the actuator mounting portion 2B and having a diameter larger than that of the actuator mounting portion 2B. The resin cover forming portion 2C is included.
[0027]
Further, an annular thin portion 2D is provided at an intermediate position in the length direction of the actuator mounting portion 2B so as to surround a gap S between a valve body 7 and a core tube 8 which will be described later. The mounting portion 2B is divided into a valve body side tube portion 2B2 in which a later-described valve body 7 is housed so as to be displaceable and a core member side tube portion 2B3 into which the core tube 8 is inserted. The thin-walled portion 2D increases the magnetic resistance between the valve element side cylinder portion 2B2 and the core member side cylinder portion 2B3 to magnetically cut off between the two, and a magnetic field described later between these cylinder portions 2B2 and 2B3. H is prevented from being short-circuited.
[0028]
Here, the stainless steel material constituting the magnetic cylinder 2 will be described. This stainless steel material is, for example, a ferrite type containing 0.01 to 0.12 wt% (preferably 0.01 to 0.05 wt%) of carbon. It is formed as a stainless steel material, and contains 16% by weight or more of chromium, 0.08% by weight or more of nickel, and 0.2 to 0.6% by weight of titanium, and the titanium content is larger than the carbon content. Is formed.
[0029]
In this case, in the present embodiment, as shown in Examples 1, 2, or 3 in Table 1 below, the magnetic cylinder 2 is formed using a ferritic stainless material such as SUS430M2, SUS430M3, SUS430WD, or the like.
[0030]
[Table 1]

[0031]
And in this Embodiment, while ensuring the intensity | strength, corrosion resistance, etc. of the magnetic cylinder 2 using a ferritic stainless material, the softness | flexibility (elongation etc.) of the magnetic cylinder 2 is made with titanium as shown in Table 2 mentioned later. This improves the workability when performing deep drawing or the like.
[0032]
Reference numeral 3 denotes a fuel passage provided in the magnetic cylinder 2. The fuel passage 3 extends in the axial direction from the resin cover forming portion 2C of the magnetic cylinder 2 to the position of the valve seat member 5 as shown in FIG. . A fuel filter 4 is provided in the resin cover forming portion 2 </ b> C to filter the fuel supplied from the base end side of the magnetic cylinder 2 into the fuel passage 3.
[0033]
Reference numeral 5 denotes a cylindrical valve seat member fitted in the valve seat member mounting portion 2A of the magnetic cylinder 2, and the valve seat member 5 includes a fuel in the fuel passage 3 as shown in FIG. And an approximately conical valve seat 5B formed so as to surround the injection port 5A. The outer peripheral side of the valve seat member 5 is welded to the valve seat member mounting portion 2A over the entire circumference. Further, a nozzle plate 6 in which a plurality of nozzle holes 6A are formed is fixed to the tip surface of the valve seat member 5 at a position covering the injection port 5A.
[0034]
Reference numeral 7 denotes a valve body that is displaceably accommodated in the valve body side cylinder portion 2B2 of the magnetic cylinder body 2. The valve body 7 includes a cylindrical valve shaft 7A extending in the axial direction, as shown in FIG. A spherical valve portion 7B that is fixed to the distal end side of the valve shaft 7A and is attached to and detached from the valve seat 5B of the valve seat member 5, and is formed on the proximal end side of the valve shaft 7A by, for example, a magnetic metal material, and the magnetic cylinder 2 It is comprised by the cylindrical adsorption | suction part 7C inserted by the inside so that sliding was possible.
[0035]
When the valve body 7 is closed, the valve portion 7B is held in a state of being seated on the valve seat 5B of the valve seat member 5 by a spring force of an urging spring 9 described later. At this time, the base end surface of the suction portion 7C and The core cylinder 8 faces the gap C in the axial direction. Further, when power is supplied to an electromagnetic coil 11 which will be described later, when the magnetic field H in FIG. 2 is formed by the electromagnetic coil 11, the valve body 7 is magnetically attracted by the attracting portion 7 </ b> C by the core tube 8, and is energized. The valve is opened against the spring force of the spring 9.
[0036]
8 is a core cylinder as a core member formed in a cylindrical shape by, for example, a magnetic metal material, and the core cylinder 8 is inserted into the core member side cylinder portion 2B3 of the magnetic cylinder 2 by means such as press fitting, It is fixed to the magnetic cylinder 2.
[0037]
Reference numeral 9 denotes an urging spring provided in the magnetic cylinder 2, and the urging spring 9 includes a cylindrical spring receiver 10, a valve body 7, and the like that are fixed to the inner peripheral side of the core cylinder 8 by means such as press fitting. The valve body 7 is always urged in the valve closing direction.
[0038]
Reference numeral 11 denotes an electromagnetic coil as an electromagnetic actuator provided by being fitted on the outer peripheral side of the actuator mounting portion 2B of the magnetic cylindrical body 2. The electromagnetic coil 11 is supplied with power using a connector 15 to be described later to generate a magnetic field H. The valve body 7 is opened against the spring force of the urging spring 9.
[0039]
Reference numeral 12 denotes a magnetic cover formed in a stepped cylindrical shape by, for example, a magnetic metal material, and the magnetic cover 12 is a large-diameter cylindrical portion 12A provided on the outer peripheral side of the electromagnetic coil 11 as shown in FIGS. And a small-diameter cylindrical portion 12B that is integrally formed on the distal end side of the large-diameter cylindrical portion 12A and is fitted and fixed to the outer peripheral side of the valve-body-side cylindrical portion 2B2 of the magnetic cylindrical body 2. Further, between the large diameter cylindrical portion 12A and the core member side cylindrical portion 2B3 of the magnetic cylindrical body 2, a connecting core 13 formed in a substantially C shape by a magnetic material or the like is inserted.
[0040]
Thereby, the magnetic cover 12 is magnetically coupled to the magnetic cylinder 2 on both sides in the axial direction with the electromagnetic coil 11 sandwiched between the small-diameter cylindrical portion 12B and the coupling core 13. When the electromagnetic coil 11 is operated, the valve body side cylinder part 2B2 and the core member side cylinder part 2B3 of the magnetic cylinder 2 are substantially magnetically cut off by the thin part 2D, so that these cylinder parts 2B2, 2B3 and The magnetic field H can be stably formed along the adsorbing portion 7C of the valve body 7, the core cylinder 8, the magnetic cover 12, and the connecting core 13, and the valve body 7 is magnetically adsorbed by the core cylinder 8 to open the valve. be able to.
[0041]
Reference numeral 14 denotes a resin cover provided on the outer peripheral side of the resin cover forming portion 2C of the magnetic cylinder 2 by means of, for example, injection molding. The resin cover 14 supplies power to the electromagnetic coil 11 as shown in FIG. The connector 15 to be molded is integrally molded with resin.
[0042]
The fuel injection valve according to the present embodiment has the above-described configuration, and the operation thereof will be described next.
[0043]
First, when the injection valve is actuated, if power is supplied from the connector 15 to the electromagnetic coil 11, a magnetic field H is formed as shown in FIG. 2, and this magnetic field H is a gap S between the suction portion 7 </ b> C of the valve body 7 and the core cylinder 8. To go through. As a result, the valve body 7 is magnetically attracted by the core cylinder 8 and is displaced in the axial direction against the biasing spring 9, so that the valve portion 7B is separated from the valve seat 5B of the valve seat member 5. Open the valve. Thus, the fuel supplied into the fuel passage 3 is injected from the injection port 5A toward the intake pipe of the engine.
[0044]
Further, the assembly operation of the injection valve will be described. First, in the magnetic cylinder forming process shown in FIGS. 4 to 7, the magnetic cylinder 2 is formed by, for example, performing three-stage deep drawing on the metal plate 16.
[0045]
In this step, as shown in FIG. 4, first, a thin metal plate 16 formed of a ferritic stainless material that becomes the magnetic cylinder 2 is prepared. Next, the metal plate 16 is disposed between the die 17A and the presser plate 17B of the press working device 17 as shown in FIG. 5, and the metal plate 16 is moved in the plate thickness direction by the punch 17C having a predetermined outer diameter. By subjecting the metal plate 16 to plastic deformation, a first deep drawing process is performed on the metal plate 16 to form, for example, a small-diameter portion 16A that becomes the valve seat member mounting portion 2A of the magnetic cylinder 2.
[0046]
Next, as shown in FIG. 6, a second deep drawing process is performed using a die 17D, a holding plate 17E, and a punch 17F corresponding to the actuator mounting portion 2B of the magnetic cylinder 2 so that the proximal end side of the small diameter portion 16A is obtained. An intermediate diameter portion 16B to be the actuator mounting portion 2B is formed on the base plate, and a third deep drawing is performed using a punch or the like corresponding to the resin cover forming portion 2C, so that an actuator is provided on the proximal end side of the intermediate diameter portion 16B. A large-diameter portion to be the attachment portion 2B is formed. Then, these cylindrical portions are separated from the metal plate 16, and the thin-walled portion 2D is provided by means of, for example, cutting or pressing, thereby forming the magnetic cylinder 2 as shown in FIG.
[0047]
In this case, as shown in Examples 1 to 3 in Table 1, the metal plate 16 to be the magnetic cylinder 2 is formed of a ferritic stainless material containing titanium. For example, as shown in Table 2 below. Compared with SUS430 stainless material listed as a comparative example, the elongation of the metal plate 16 is increased, and the hardness (in Table 2 below, the measured value of Vickers hardness is exemplified as the hardness) is formed to be moderately soft. Can do.
[0048]
[Table 2]

[0049]
As a result, when the magnetic cylinder 2 is processed and formed, the metal plate 16 can be flexibly plastically deformed by the press working device 17, and even when the thin magnetic cylinder 2 having the step portions 2B1, 2C1 and the like is press-formed. It is possible to prevent the metal plate 16 from being damaged such as cracks and breaks due to unreasonable deformation during the forming process.
[0050]
Next, in the component assembling step shown in FIG. 8, first, the electromagnetic coil 11, the magnetic cover 12, and the connecting core 13 are assembled on the outer peripheral side of the magnetic cylinder 2, and the resin cover 14 is injection molded on these outer peripheral sides. The injection valve can be assembled by assembling the valve body 7, the core cylinder 8, the urging spring 9, the spring receiver 10 and the like to the magnetic cylinder 2.
[0051]
Thus, according to the present embodiment, since the magnetic cylinder 2 is made of a ferritic stainless material containing titanium, the strength and corrosion resistance of the magnetic cylinder 2 are secured and the flexibility thereof is increased. be able to. Thereby, when forming the magnetic cylinder 2, the metal plate 16 can be stably plastically deformed by means such as deep drawing, and the workability can be improved.
[0052]
Therefore, even when the thin and long stepped cylindrical cylindrical magnetic cylinder 2 is formed, the magnetic cylinder 2 can be easily processed and molded using the metal plate 16 by means such as deep drawing, and the valve seat member is attached. High dimensional accuracy and stable strength can be given to the portion 2A, the actuator mounting portion 2B, the resin cover forming portion 2C, and the like. Thereby, the yield of the magnetic cylinder 2 can be increased, and the productivity and reliability of the injection valve can be improved.
[0053]
In this case, the content of titanium contained in the magnetic cylinder 2 is, for example, 0.2 to 0.6% by weight, and is formed so as to be larger than the content of carbon. Can be formed to be moderately soft within an allowable range, and the elongation can be sufficiently increased. Moreover, since the carbon content can be suppressed to a low level, the corrosion resistance of the magnetic cylinder 2 can be improved.
[0054]
Moreover, since the ferritic stainless steel material used as the magnetic cylinder 2 has a carbon content of 0.05 wt% or less as shown in Examples 1 to 3 in Table 1, the corrosion resistance is further improved. Can be improved. In particular, since the stainless steel material of Example 2 contains, for example, 0.3% by weight or more of molybdenum, it is possible to further increase the corrosion resistance and extend the life of the injection valve.
[0055]
On the other hand, the magnetic cylinder 2 is formed integrally with a metal pipe or the like, and the thin portion 2D is provided in the middle of the magnetic cylinder 2. Therefore, when assembling the injection valve, the metal pipe is subjected to mechanical processing such as press working or cutting. As a result, it is possible to easily form the magnetic cylinder 2 provided with the thin-walled portion 2D serving as a magnetic blocking portion, and to reduce the number of parts of the injection valve and simplify the structure.
[0056]
Next, FIGS. 9 to 11 show a second embodiment according to the present invention. The feature of this embodiment is that a magnetic cylinder is formed by bending a metal plate into a cylindrical shape and welding it. is there.
[0057]
21 is a magnetic cylinder used in place of the magnetic cylinder 2 of the first embodiment. The magnetic cylinder 21 is made of a ferritic stainless steel material containing titanium, as in the first embodiment. The valve seat member mounting portion 21A, the actuator mounting portion 21B, the resin cover forming portion 21C, the thin portion 21D, the step portions 21B1, 21C1, and the cylindrical portions 21B2, 21B3 are configured. However, the magnetic cylinder 21 is made of a metal plate curved in a cylindrical shape, and a welded portion 22 extending over the entire length of the magnetic cylinder 21 by a welding means such as seam welding at one place in the circumferential direction. Is provided.
[0058]
In this case, when the magnetic cylinder 21 is formed, as shown in FIG. 10, first, the metal plate is bent into a cylindrical shape by means of roll processing or the like, and both ends thereof are brought into contact with each other to perform welding means such as seam welding. Thus, the cylindrical body 23 is formed. Then, for example, the cylindrical body 23 is processed into a stepped cylinder by drawing the cylindrical body 23 from the outside in the radial direction using a roll 24, a rod 25, and the like, and each portion in the length direction is formed into a magnetic cylinder. The valve seat member mounting portion 21A, the actuator mounting portion 21B, and the resin cover forming portion 21C of the body 21 are formed.
[0059]
Thus, in the present embodiment configured as described above, it is possible to obtain substantially the same functions and effects as those of the first embodiment. In particular, in the present embodiment, it is possible to easily process and form the elongated stepped cylindrical magnetic cylinder 21 only by bending the metal plate into a cylindrical shape and applying means such as seam welding and drawing. .
[0060]
In each of the above-described embodiments, the

magnetic cylinders

2 and 21 are made of a ferritic stainless steel material containing titanium. However, the present invention is not limited to this, and for example, a ferritic stainless steel material containing titanium is 0.3. It is good also as a structure which contains more than weight% copper (Cu), 0.3 weight% or more niobium (Nb), or these both elements, and raises the corrosion resistance and intensity | strength of a magnetic cylinder further.
[0061]
In each of the above embodiments, for example, a ferritic stainless material such as SUS430M2, SUS430M3, and SUS430WD is used. However, the types of elements included in the magnetic cylinder of the present invention, the specific values of the content, etc. Of course, the present invention is not limited to these examples, and the present invention is applicable to various ferritic stainless steel materials containing titanium while suppressing the carbon content.
[0062]
【The invention's effect】
As detailed above, according to the invention of claim 1, the magnetic cylinder is The valve seat member mounting portion located on one side in the axial direction and the actuator mounting portion formed integrally with the other side in the axial direction of the valve seat member mounting portion via a stepped portion and having a diameter larger than that of the valve seat member mounting portion. And a stepped cylindrical body including a resin cover forming portion integrally formed through a step portion on the other axial side of the actuator mounting portion and having a diameter larger than that of the actuator mounting portion, Using ferritic stainless steel containing titanium Forming and providing a valve seat member fitted in the valve seat member mounting portion of the magnetic cylinder, providing an electromagnetic actuator on the outer peripheral side of the actuator mounting portion, and on the outer peripheral side of the resin cover forming portion, Provide a resin cover in which the connector for supplying power to the electromagnetic actuator is integrally molded with resin Constitution When Shi ing So Using a ferritic stainless material containing titanium, a stepped magnetic cylinder including a valve seat member mounting portion, an actuator mounting portion, and a resin cover forming portion can be easily processed and molded. For example, the valve seat member mounting portion of the magnetic cylinder can be formed with a valve seat member mounting portion, the actuator mounting portion with an electromagnetic actuator mounting portion, and the resin cover forming portion with a connector integrally formed with resin. A molded resin cover can be provided. Moreover, by using a ferritic stainless material containing titanium, While ensuring the strength and corrosion resistance of the magnetic cylinder, it is possible to increase its flexibility. Thereby, for example, even when a thin and long magnetic cylinder is formed, the stainless steel material can be stably plastically deformed, and its workability can be improved. Therefore, high dimensional accuracy and stable strength can be given to each part of the magnetic cylinder, the yield of the magnetic cylinder can be increased, and the productivity and reliability of the injection valve can be improved.
[0063]
According to the invention of claim 2, since the ferritic stainless material of the magnetic cylinder contains 0.2 to 0.6% by weight of titanium, the hardness of the stainless steel material is set according to the content of titanium. It can be formed to be moderately soft within an allowable range, and its elongation can be sufficiently increased. Thereby, even if it is a magnetic cylinder of a complicated shape, the process shaping | molding can be performed easily.
[0064]
According to the invention of claim 3, the ferritic stainless material of the magnetic cylinder contains 0.01 to 0.12% by weight of carbon, and the titanium content is larger than the carbon content. Thus, the ferritic stainless steel material can be formed while suppressing the carbon content contained in the stainless steel material, and the corrosion resistance can be improved. Moreover, the stable softness | flexibility can be given to a stainless steel material by containing more titanium than carbon.
[0066]

Claims

4 According to the invention, the magnetic cylinder is Made of ferritic stainless steel containing titanium Metal plate , Since it is configured to be plastically deformed into a cylindrical shape by deep drawing processing means, for example, even when forming a thin and long magnetic cylinder, a ferritic stainless steel material containing titanium is used in the plate thickness direction by a jig such as a punch. And can be easily plastically deformed, and can be easily processed.
[0067]

Claims

5 According to the invention, since the magnetic cylinder is provided with the thin portion that increases the magnetic resistance of the magnetic cylinder at the position of the gap between the valve element and the core member, for example, press working, cutting, etc. By simply applying the machining process to the magnetic cylinder, it is possible to easily form a thin-walled portion that becomes a magnetic blocking part. When the electromagnetic actuator operates, the thin-walled portion stabilizes the magnetic field between the valve body and the core member. Can be formed.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a fuel injection valve according to a first embodiment of the present invention.
FIG. 2 is a partially enlarged cross-sectional view showing a tip side of a fuel injection valve.
FIG. 3 is an enlarged cross-sectional view of the fuel injection valve as viewed from the direction of arrows III-III in FIG.
FIG. 4 is a partial enlarged cross-sectional view showing a metal plate formed of a ferritic stainless material containing titanium to be a magnetic cylinder.
FIG. 5 is a partial enlarged cross-sectional view showing a state in which a portion to be a valve seat member mounting portion of the magnetic cylinder is formed by performing the first deep drawing on the metal plate.
FIG. 6 is a partially enlarged cross-sectional view showing a state in which a portion to be an actuator mounting portion of the magnetic cylinder is formed by performing a second deep drawing on the metal plate.
FIG. 7 is a longitudinal sectional view showing a single magnetic cylinder formed by subjecting a metal plate to a third deep drawing and the like.
FIG. 8 is a longitudinal sectional view showing a state in which each part is attached to a magnetic cylinder and an injection valve is assembled.
FIG. 9 is a longitudinal sectional view showing a magnetic cylinder of a fuel injection valve according to a second embodiment of the present invention.
FIG. 10 is a partially enlarged cross-sectional view showing a state in which a cylindrical body that becomes a magnetic cylindrical body is formed from a metal plate.
FIG. 11 is a partially enlarged cross-sectional view showing a state in which a cylindrical body is drawn.
[Explanation of symbols]
1 Valve casing
2,21 Magnetic cylinder
2A, 21A Valve seat member mounting part
2B, 21B Actuator mounting part
2C, 21C resin cover forming part
2D, 21D thin part
3 Fuel passage
5 Valve seat members
5A injection port
5B Valve seat
7 Disc
8 Core cylinder (core member)
9 Biasing spring
11 Electromagnetic coil (electromagnetic actuator)
12 Magnetic cover
13 Linked core
14 Resin cover
15 Connector
S clearance

Claims

A magnetic cylinder formed in a cylindrical shape with a magnetic material and having a fuel passage inside, a valve seat member provided in the magnetic cylinder and surrounding the injection port and formed with a valve seat, and displaceable in the magnetic cylinder the fuel injection valve electromagnetic actuator provided comprising a valve body which Hanaregi seats on the valve seat of the valve seat member by activating the,
The magnetic cylinder body is formed integrally with a valve seat member mounting portion located on one side in the axial direction and a step portion on the other side in the axial direction of the valve seat member mounting portion, and is larger than the valve seat member mounting portion. As a stepped cylindrical body including a diameter actuator mounting portion and a resin cover forming portion which is integrally formed via a step portion on the other side in the axial direction of the actuator mounting portion and has a diameter larger than that of the actuator mounting portion, Formed using a ferritic stainless material containing titanium ,
The valve seat member is fitted and provided in the valve seat member mounting portion of the magnetic cylinder, the electromagnetic actuator is provided on the outer peripheral side of the actuator mounting portion, and the outer periphery side of the resin cover forming portion is fuel injector connector for supplying power to the electromagnetic actuator is characterized in that a configuration in which the resin cover is a resin integrally molded.

2. The fuel injection valve according to claim 1, wherein the ferritic stainless material of the magnetic cylindrical body contains 0.2 to 0.6 wt% of the titanium.

The ferritic stainless material of the magnetic cylinder contains 0.01 to 0.12% by weight of carbon and is formed so that the content of titanium is larger than the content of carbon. The fuel injection valve described in 1.

The magnetic cylindrical body, a metal plate made of ferritic stainless material containing the titanium, deep drawing means by tubular obtained by forming by plastic deformation in claim 1, 2 or 3 to the fuel injection valve according .

A core member facing the valve body with an axial gap interposed therebetween is provided in the magnetic cylinder, and the magnetic cylinder is a thin portion that increases the magnetic resistance of the magnetic cylinder at a position where the gap is formed. The fuel injection valve according to claim 1, 2, 3 or 4 .