JP3897100B2

JP3897100B2 - Fuel injection device

Info

Publication number: JP3897100B2
Application number: JP2002162578A
Authority: JP
Inventors: 義久山本
Original assignee: Denso Corp
Current assignee: Denso Corp
Priority date: 2002-06-04
Filing date: 2002-06-04
Publication date: 2007-03-22
Anticipated expiration: 2022-06-04
Also published as: JP2004011451A

Description

【０００１】
【発明の属する技術分野】
本発明は、内燃機関（以下、内燃機関を「エンジン」という。）の燃料噴射装置（以下、「燃料噴射装置」をインジェクタという。）に関する。
【０００２】
【従来の技術】
従来、通電を制御されることにより伸縮する圧電素子を駆動部の駆動源として用いて弁部材としてのノズルニードルを駆動し、噴孔を開閉するインジェクタが公知である。圧電素子に代え通電制御に伴う磁束密度の変化により伸縮する磁歪素子を駆動部の駆動源として用いることも公知である。このようなインジェクタにおいて、駆動部から弁部材への駆動力の伝達を駆動部と弁部材とを機械的に結合して行うのではなく、制御室に充填された作動流体を介して行うものが知られている。作動流体として燃料を用いることが一般的である。制御室には、駆動部の伸縮に伴い駆動部とともに往復移動する伝達部材と弁部材の反噴孔側とが面している。駆動部の伸縮に伴い伝達部材が往復移動することにより、制御室の作動流体を介して駆動部の駆動力がノズルニードルに伝わり、ノズルニードルは往復移動する。
【０００３】
特開平６−２８０７１１号公報および特開平１１−３７０１３号公報に開示されているインジェクタでは、伝達部材を往復移動可能に収容するハウジングの内壁と伝達部材との間から制御室の作動流体が駆動部側に漏れることを防止するため、伝達部材の外周壁にＯリング等のシール部材を取り付けている。
【０００４】
【発明が解決しようとする課題】
しかしながら、駆動部の伸縮とともに伝達部材が往復移動すると、Ｏリングはハウジングの内壁と摺動し摩耗するという問題がある。
ドイツ特許１９８０２４９５号では、制御室の伝達部材側を薄膜で液密に閉塞し、薄膜と伝達部材とを当接させている。伝達部材が往復移動すると薄膜が変形し、駆動部の駆動力がノズルニードルに加わる。薄膜により制御室の作動流体が駆動部側に漏れることを防止するので、伝達部材にＯリング等のシール部材を取り付ける必要がない。
【０００５】
エンジンの要求性能特性に応じ、エンジン毎に駆動部の伸縮量、つまり伝達部材の移動量に対するノズルニードルのリフト量の変換率を変更したいことがある。変換率は、駆動部の伸縮量に対するノズルニードルのリフト量の割合を意味する。伝達部材またはノズルニードルを交換し、伝達部材とノズルニードルとが制御室から往復移動方向に圧力を受ける受圧面積の比率を変更すれば、駆動部の伸縮量に対するノズルニードルのリフト量の変換率を変更できる。高精度な加工を要するノズルニードルよりも伝達部材を交換することが望ましい。伝達部材の受圧面積を変更するために伝達部材を交換することは、伝達部材の外径が変化することを意味する。
【０００６】
しかし、特開平６−２８０７１１号公報および特開平１１−３７０１３号公報のインジェクタでは、伝達部材の外周に設置したＯリングと伝達部材を収容しているハウジングの内壁との摺動部で燃料をシールしている。したがって、伝達部材を交換すると、ハウジングの内壁の内径を変更する必要がある。つまり、ハウジングを交換する必要がある。したがって、伝達部材の移動量に対するノズルニードルのリフト量の変換率を変更するために、伝達部材およびハウジングの２部品を交換しなければならない。
【０００７】
ドイツ特許１９８０２４９５号のインジェクタでは制御室の燃料が駆動部に漏れることを薄膜が防止しており、駆動部の伸縮量に対するノズルニードルのリフト量の変換率を変更するためには、伝達部材を交換する必要がある。交換率を大きく変更する場合は伝達部材を収容するハウジングを交換する必要がある。しかも、薄膜と伝達部材とが当接し伝達部材の往復移動に合わせて薄膜が変位するので、薄膜が破損しやすいという問題がある。
【０００８】
本発明の目的は、収容室および制御室を形成するハウジングの内壁に取り付けられた作動部材が摩耗および破損しにくく、作動部材により制御室側から駆動部に作動流体が漏れることを防止し、弁部材のリフト量を容易に変更できるインジェクタを提供することにある。
【０００９】
【課題を解決するための手段】
本発明の請求項１または５記載のインジェクタによると、伝達部材は駆動部の伸縮にともない往復移動し、伝達部材と当接している作動部材は伝達部材を往復移動可能に収容する収容室を作動部材が伝達部材と当接している当接側と作動部材が伝達部材と当接していない非当接側とに液密に仕切っている。作動部材は収容室を形成するハウジングの内壁に取り付けられており、収容室の非当接側と制御室とに充填されている作動流体が駆動部側に漏れることを作動部材が防止する。したがって、Ｏリング等のシール部材が不要になる。
【００１０】
また、収容室の非当接側および制御室に充填された作動流体から往復移動方向に圧力を受ける作動部材の剛体部の受圧面積を変更することにより、駆動部の伸縮にともない往復移動する剛体部の移動量に対する弁部材のリフト量の変換率を変更できる。剛体部の受圧面積が変わってもハウジングの内壁に作動部材を取り付ける変形部の外周縁形状を変更する必要はない。したがって、作動部材を取り付けているハウジングを変更する必要はない。つまり、作動部材を交換するだけで駆動部の伸縮量に対する弁部材のリフト量の変換率を変更できる。
また変形部よりも剛性の高い剛体部が伝達部材と当接し、変形部は伝達部材と当接しないので、作動部材が摩耗および破損しにくい。
【００１１】
本発明の請求項２記載のインジェクタによると、剛体部が制御室の作動流体から往復移動方向に流体圧力を受ける受圧面積は、弁部材が制御室の作動流体から往復移動方向に流体圧力を受ける受圧面積よりも大きい。伝達部材の往復移動量、つまり駆動部の伸縮量に対し弁部材のリフト量の変換率を大きくすることができる。したがって、駆動部の伸縮量が小さくても弁部材のリフト量を大きくすることができる。
【００１２】
本発明の請求項３記載のインジェクタによると、伝達部材と剛体部とは平面同士で当接するので、伝達部材に対し剛体部が傾きにくい。伝達部材の移動量に対し剛体部の移動量がばらつかないので、弁部材のリフト量がばらつくことを防止する。
本発明の請求項４記載のインジェクタによると、作動部材を一部材で構成しているので、プレスや樹脂成形等により作動部材を容易に製造できる。
【００１３】
【発明の実施の形態】
以下、本発明の実施の形態を示す複数の実施例を図に基づいて説明する。
（第１実施例）
本発明の第１実施例によるインジェクタを図１に示す。図１は模式的にインジェクタ１０を示しているので、１部材で示されている部材が複数の部材で構成されている場合もある。インジェクタ１０は、例えば図示しないデリバリパイプで一定圧に蓄圧された燃料をガソリンエンジンの各気筒に噴射する燃料噴射装置である。
【００１４】
インジェクタ１０のハウジングは、弁ボディ１２、プレート１６およびハウジング本体１７で構成されている。弁ボディ１２、プレート１６およびハウジング本体１７はリテーニングナット１８で結合されている。デリバリパイプで蓄圧された燃料は弁ボディ１２、プレート１６およびハウジング本体１７に形成されている燃料通路１００を通り、弁部材としてのノズルニードル２０の周囲に形成されている燃料溜まり１０２に供給される。
弁ボディ１２の底部を貫通して噴孔１３が形成されている。弁ボディ１２の内壁にノズルニードル２０が着座可能な弁座１４が形成されている。ノズルニードル２０が弁座１４に着座すると、噴孔１３からの燃料噴射が遮断される。
【００１５】
ノズルニードル２０の往復移動方向の一方の端面である反噴孔側端面、弁ボディ１２の内壁およびプレート１６の内壁により制御室１１０が形成されている。コイルスプリング２２は制御室１１０に収容されており、噴孔１３を閉塞する方向である弁座１４に向けノズルニードル２０を付勢している。
【００１６】
ハウジング本体１７に収容室１１４および収容室１２０が形成されている。作動部材３０は収容室１１４に往復移動可能に収容され、伝達部材４０および駆動部５０は収容室１２０に収容されている。図２に示すように、作動部材３０は、弾性を有する環状の変形部３２と、作動部材３０の中央に位置し変形部３２の内周と結合し変形部３２よりも厚い剛体部３４とを有している。作動部材３０は１部材で形成されている。燃料に対する耐性があり、伝達部材４０と往復移動するときに変形部３２が変形し剛体部３４が変形しないのであれば、作動部材３０としてどのような材質を用いてもよい。例えば、金属をプレス加工して作動部材３０を製造してもよいし、樹脂で一体成形して作動部材３０を製造してもよい。
【００１７】
図１に示すように、変形部３２の外周縁部はハウジング本体１７の内壁に取り付けられ固定されている。剛体部３４は伝達部材４０のシャフト４２と平面同士で当接している。作動部材３０は、剛体部３４が伝達部材４０のシャフト４２と当接していない非当接側１１６と剛体部３４がシャフト４２と当接している当接側１１８とに収容室１１４を液密に仕切っている。収容室１１４の非当接側１１６は連通路１１２により制御室１１０と連通している。弁ボディ１２とノズルニードル２０との摺動部から収容室１１４の非当接側１１６と制御室１１０とに作動流体として燃料が微量ではあるが漏れているので、収容室１１４の非当接側１１６と制御室１１０とに燃料が充填されている。図１では、収容室１１４の非当接側１１６と制御室１１０とは密封された空間として示されている。これに対し、燃料通路１００から連通路を通り収容室１１４の非当接側１１６と制御室１１０とに燃料を供給する構成でもよい。コイルスプリング３８は伝達部材４０側に作動部材３０を付勢している。
【００１８】
伝達部材４０は駆動部５０の作動部材３０側に設置されており、駆動部５０の伸縮にともない往復移動する。板ばね４４は駆動部５０に向け伝達部材４０を付勢している。
駆動部５０は図１に示すハウジング本体１７の上部内壁に係止されており、ターミナル６０と電気的に接続されている。駆動部５０は、駆動源として圧電素子を用いており、圧電素子を積層して形成されている。駆動部５０は、ターミナル６０から電圧が印加されると伝達部材４０側に伸び、電圧の印加を遮断すると縮む。図１は駆動部５０にターミナル６０から電圧が印加されている状態を示している。
【００１９】
次に、駆動部５０への通電制御によるインジェクタ１０の作動について説明する。
ターミナル６０から駆動部５０に電圧が印加されると、駆動部５０は伝達部材４０側に伸びる。伝達部材４０は駆動部５０の伸び量と同じ移動量で図１の下方である作動部材３０側に移動する。作動部材３０の剛体部３４は伝達部材４０のシャフト４２と当接しているので、伝達部材４０と同じ移動量で剛体部３４は制御室１１０側に移動する。収容室１１４の非当接側１１６および制御室１１０に燃料が充填されているので、剛体部３４がノズルニードル２０側に移動すると、駆動部５０の駆動力が伝達部材４０、作動部材３０の剛体部３４、収容室１１４の非当接側１１６および制御室１１０に充填されている燃料を介し弁座１４に向けた力としてノズルニードル２０に加わる。つまり、駆動部５０が伸びることにより収容室１１４の非当接側１１６および制御室１１０の燃料圧力が上昇し、収容室１１４の非当接側１１６および制御室１１０の燃料から弁座１４に向けてノズルニードル２０が受ける力が増加する。したがって、収容室１１４の非当接側１１６および制御室１１０の燃料から弁座１４に向けてノズルニードル２０が受ける力とコイルスプリング２２から弁座１４に向けてノズルニードル２０が受ける力との和は、燃料溜まり１０２の燃料により弁座１４から離座する方向に受ける力よりも大きくなる。したがって、ノズルニードル２０は弁座１４に着座し、噴孔１３からの燃料噴射は遮断される。
【００２０】
駆動部５０への電圧の印加が遮断されると、駆動部５０は図１に示す状態から図１の上方に向けて縮む。伝達部材４０は板ばね４４により駆動部５０に向けて付勢されているので、駆動部５０とともに図１の上方に移動する。作動部材３０の剛体部３４はコイルスプリング３８の付勢力により伝達部材４０側に付勢されているので、伝達部材４０とともに図１の上方に移動する。つまり、駆動部５０が縮むことにより収容室１１４の非当接側１１６および制御室１１０の燃料圧力が低下し、収容室１１４の非当接側１１６および制御室１１０の燃料から弁座１４に向けてノズルニードル２０が受ける力が低下する。したがって、収容室１１４の非当接側１１６および制御室１１０の燃料から弁座１４に向けてノズルニードル２０が受ける力とコイルスプリング２２から弁座１４に向けてノズルニードル２０が受ける力との和は、燃料溜まり１０２の燃料により弁座１４から離座する方向に受ける力よりも小さくなる。したがって、ノズルニードル２０は弁座１４から離座し、噴孔１３から燃料が噴射される。
【００２１】
駆動部５０の伸縮にともない、伝達部材４０のシャフト４２と当接している作動部材３０の剛体部３４は伝達部材４０とともに往復移動する。剛体部３４が収容室１１４の非当接側１１６および制御室１１０の燃料から往復移動方向に圧力を受ける受圧面積をＳ１、駆動部５０の伸縮量、つまり伝達部材４０および作動部材３０の往復移動量をＬ１、ノズルニードル２０が収容室１１４の非当接側１１６および制御室１１０の燃料から往復移動方向に圧力を受ける受圧面積をＳ２、ノズルニードル２０のリフト量をＬ２とすると、Ｓ１×Ｌ１＝Ｓ２×Ｌ２である。ノズルニードル２０のリフト量Ｌ２は剛体部３４の受圧面積Ｓ１に比例し、受圧面積Ｓ１が大きくなると大きくなる。したがって、ノズルニードル２０の受圧面積Ｓ２を一定にすると、駆動部５０の伸縮量Ｌ１を変更することなく、作動部材３０を交換し剛体部３４の受圧面積Ｓ１を変更することにより、ノズルニードル２０のリフト量Ｌ２を変更できる。つまり、駆動部５０の伸縮量Ｌ１に対するノズルニードル２０のリフト量Ｌ２の変換率を変更できる。これにより、燃料噴射率または燃料噴射量を変更できる。また、ノズルニードル２０が収容室１１４の非当接側１１６および制御室１１０の燃料から弁座１４に向けて受ける力は、剛体部３４の受圧面積Ｓ１に反比例し、受圧面積Ｓ１が大きくなると小さくなる。
【００２２】
作動部材３０は変形部３２により収容室１１４を形成するハウジング本体１７に取り付けられているので、剛体部３４の受圧面積を変更しても変形部３２の外径を変更しなければ、ハウジング本体１７の内径を変更する必要はない。したがって、ハウジング本体１７を交換する必要はない。
【００２３】
第１実施例では、剛体部３４が収容室１１４の非当接側１１６および制御室１１０の燃料から往復移動方向に圧力を受ける受圧面積は、ノズルニードル２０が非当接側１１６および制御室１１０の燃料から往復移動方向に圧力を受ける受圧面積よりも大きい。したがって、駆動部５０の伸縮量が小さくても、ノズルニードル２０のリフト量を大きくすることができる。
【００２４】
また、剛体部３４とシャフト４２とが平面同士で当接しているので、伝達部材４０とともに剛体部３４が往復移動するとき、剛体部３４が傾斜しにくい。伝達部材４０の移動量に対し剛体部３４の移動量がばらつかないのでノズルニードル２０のリフト量がばらつかない。したがって、燃料噴射量を高精度に制御できる。
【００２５】
さらに、作動部材３０を１部材で構成しているので、前述したように金属によるプレス加工や樹脂による一体成形により作動部材を容易に製造できる。
第１実施例では、ノズルニードル２０を駆動する駆動部５０の駆動源として圧電素子を用いたが、駆動源として磁歪素子を用いてもよい。
【００２６】
（第２実施例、第３実施例）
本発明の第２実施例を図３に、第３実施例を図４に示す。
図３に示す第２実施例の作動部材７０では、変形部７２と剛体部７４とは別部材であり、円板状の変形部７２に剛体部７４が接着等により結合されている。図４に示す第３実施例の作動部材８０では、変形部８２と剛体部８４とは別部材であり、剛体部８４の外周に円環状の変形部８２が溶接等により接合されている。変形部７２、８２は収容室１１４を形成するハウジング本体１７の内壁に取り付けられている。剛体部７４、８４は伝達部材４０のシャフト４２と当接する。
【００２７】
以上説明した本発明の上記複数の実施例では、作動部材は収容室１１４を形成しているハウジング本体１７の内壁と摺動せず、作動部材が収容室１１４の非当接側１１６から当接側１１８に作動流体としての燃料が漏れることを防止する。したがって、伝達部材４０とハウジング本体１７の内壁との間から駆動部５０に燃料が漏れることを防止するため、伝達部材４０の外周にＯリング等のシール部材を設置する必要がない。
【００２８】
さらに、作動部材を交換し剛体部の受圧面積を変更することにより、ノズルニードル２０のリフト量を変更できる。つまり、駆動部５０の伸縮量に対するノズルニードル２０のリフト量の変換率を変更できる。これにより、作動部材を交換するだけで燃料噴射率または燃料噴射量を容易に変更できる。
また、作動部材の剛体部が伝達部材４０のシャフト４２と当接するので、剛体部が摩耗および破損しにくい。
【００２９】
上記複数の実施例では、駆動部５０が伸びることによりノズルニードル２０が弁座１４に着座し噴孔１３からの燃料噴射を遮断した。これに対し、駆動部５０が縮むことによりノズルニードル２０が弁座１４に着座し噴孔１３からの燃料噴射を遮断する構成を採用することも可能である。
また上記複数の実施例では、ガソリンエンジン用のインジェタに本発明を適用したが、ディーゼルエンジン用のインジェクタに本発明を適用することも可能である。
【図面の簡単な説明】
【図１】本発明の第１実施例によるインジェクタを示す模式的断面図である。
【図２】（Ａ）は第１実施例の作動部材を示す平面図であり、（Ｂ）は（Ａ）のＢ−Ｂ線断面図である。
【図３】図２の（Ｂ）と同じ断面位置における本発明の第２実施例による作動部材を示す模式的断面図である。
【図４】図２の（Ｂ）と同じ断面位置における本発明の第３実施例による作動部材を示す模式的断面図である。
【符号の説明】
１０インジェクタ（燃料噴射装置）
１２弁ボディ（ハウジング）
１３噴孔
１４弁座
１６プレート（ハウジング）
１７ハウジング本体（ハウジング）
２０ノズルニードル（弁部材）
３０、７０、８０作動部材
３２、７２、８２変形部
３４、７４、８４剛体部
４０伝達部材
５０駆動部
１１０制御室
１１４収容室
１１６収容室の非当接側
１１８収容室の当接側[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel injection device (hereinafter, “fuel injection device” is referred to as an injector) of an internal combustion engine (hereinafter, the internal combustion engine is referred to as “engine”).
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an injector that opens and closes a nozzle hole by driving a nozzle needle as a valve member using a piezoelectric element that expands and contracts by controlling energization as a drive source of a drive unit is known. It is also known to use a magnetostrictive element that expands and contracts due to a change in magnetic flux density accompanying energization control instead of a piezoelectric element as a drive source of a drive unit. In such an injector, transmission of the driving force from the driving unit to the valve member is not performed by mechanically coupling the driving unit and the valve member, but is performed via a working fluid filled in the control chamber. Are known. It is common to use fuel as the working fluid. The control chamber faces the transmission member that reciprocates with the drive unit as the drive unit expands and contracts, and the anti-injection hole side of the valve member. As the driving member expands and contracts, the transmission member reciprocates, whereby the driving force of the driving unit is transmitted to the nozzle needle via the working fluid in the control chamber, and the nozzle needle reciprocates.
[0003]
In the injectors disclosed in Japanese Patent Application Laid-Open Nos. 6-280711 and 11-37013, the working fluid in the control chamber is driven between the inner wall of the housing that houses the transmission member in a reciprocable manner and the transmission member. In order to prevent leakage to the side, a seal member such as an O-ring is attached to the outer peripheral wall of the transmission member.
[0004]
[Problems to be solved by the invention]
However, when the transmission member reciprocates as the drive unit expands and contracts, there is a problem that the O-ring slides and wears against the inner wall of the housing.
In German Patent 1802495, the transmission member side of the control chamber is liquid-tightly closed with a thin film, and the thin film and the transmission member are brought into contact with each other. When the transmission member reciprocates, the thin film is deformed, and the driving force of the driving unit is applied to the nozzle needle. Since the working fluid in the control chamber is prevented from leaking to the drive unit side by the thin film, there is no need to attach a seal member such as an O-ring to the transmission member.
[0005]
Depending on the required performance characteristics of the engine, it may be desired to change the conversion rate of the lift amount of the nozzle needle with respect to the expansion / contraction amount of the drive unit, that is, the movement amount of the transmission member, for each engine. The conversion rate means the ratio of the lift amount of the nozzle needle to the expansion / contraction amount of the drive unit. By changing the transmission member or nozzle needle and changing the ratio of the pressure receiving area where the transmission member and the nozzle needle receive pressure in the reciprocating direction from the control chamber, the conversion rate of the lift amount of the nozzle needle with respect to the expansion / contraction amount of the drive unit can be changed. Can change. It is desirable to replace the transmission member rather than a nozzle needle that requires high-precision processing. Replacing the transmission member to change the pressure receiving area of the transmission member means that the outer diameter of the transmission member changes.
[0006]
However, in the injectors disclosed in Japanese Patent Laid-Open Nos. 6-280711 and 11-37013, the fuel is sealed at the sliding portion between the O-ring installed on the outer periphery of the transmission member and the inner wall of the housing housing the transmission member. is doing. Therefore, when the transmission member is replaced, it is necessary to change the inner diameter of the inner wall of the housing. That is, it is necessary to replace the housing. Therefore, in order to change the conversion rate of the lift amount of the nozzle needle with respect to the movement amount of the transmission member, the two parts of the transmission member and the housing must be exchanged.
[0007]
In the injector of German Patent No. 1980495, the thin film prevents the fuel in the control chamber from leaking into the drive part. To change the conversion rate of the lift amount of the nozzle needle with respect to the expansion / contraction amount of the drive part, the transmission member is replaced. There is a need to. When the exchange rate is greatly changed, it is necessary to exchange the housing that houses the transmission member. Moreover, since the thin film and the transmission member come into contact with each other and the thin film is displaced in accordance with the reciprocating movement of the transmission member, there is a problem that the thin film is easily damaged.
[0008]
An object of the present invention is to prevent the working member attached to the inner wall of the housing forming the storage chamber and the control chamber from being worn and damaged, and to prevent the working fluid from leaking from the control chamber side to the drive unit by the working member. An object of the present invention is to provide an injector capable of easily changing a lift amount of a member.
[0009]
[Means for Solving the Problems]
According to the injector according to claim 1 or 5 of the present invention, the transmission member reciprocates as the drive unit expands and contracts, and the operating member in contact with the transmission member operates the accommodation chamber that accommodates the transmission member so as to reciprocate. The member is liquid-tightly divided into a contact side where the member is in contact with the transmission member and a non-contact side where the operating member is not in contact with the transmission member. The operating member is attached to the inner wall of the housing forming the storage chamber, and the operating member prevents the working fluid filled in the non-contact side of the storage chamber and the control chamber from leaking to the drive unit side. Therefore, a sealing member such as an O-ring is not necessary.
[0010]
A rigid body that reciprocates as the drive unit expands and contracts by changing the pressure receiving area of the rigid body portion of the working member that receives pressure in the reciprocating direction from the non-contact side of the storage chamber and the working fluid filled in the control chamber The conversion rate of the lift amount of the valve member with respect to the movement amount of the part can be changed. Even if the pressure receiving area of the rigid body portion changes, it is not necessary to change the outer peripheral shape of the deforming portion for attaching the operating member to the inner wall of the housing. Therefore, there is no need to change the housing to which the operating member is attached. That is, the conversion rate of the lift amount of the valve member with respect to the expansion / contraction amount of the drive unit can be changed only by replacing the operating member.
Further, since the rigid body portion having higher rigidity than the deforming portion is in contact with the transmission member and the deformation portion is not in contact with the transmission member, the operation member is not easily worn or damaged.
[0011]
According to the injector of the second aspect of the present invention, the pressure receiving area where the rigid body portion receives the fluid pressure in the reciprocating direction from the working fluid in the control chamber is such that the valve member receives the fluid pressure in the reciprocating direction from the working fluid in the control chamber. It is larger than the pressure receiving area. The conversion rate of the lift amount of the valve member can be increased with respect to the reciprocating amount of the transmission member, that is, the expansion / contraction amount of the drive unit. Therefore, the lift amount of the valve member can be increased even when the expansion / contraction amount of the drive unit is small.
[0012]
According to the injector of the third aspect of the present invention, since the transmission member and the rigid body portion are in contact with each other on the plane, the rigid body portion is not easily inclined with respect to the transmission member. Since the amount of movement of the rigid portion does not vary with respect to the amount of movement of the transmission member, the lift amount of the valve member is prevented from varying.
According to the injector of the fourth aspect of the present invention, since the operating member is constituted by one member, the operating member can be easily manufactured by pressing, resin molding or the like.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a plurality of examples showing embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
An injector according to a first embodiment of the present invention is shown in FIG. Since FIG. 1 schematically shows the injector 10, the member shown as one member may be composed of a plurality of members. The injector 10 is a fuel injection device that injects fuel accumulated at a constant pressure by a delivery pipe (not shown) into each cylinder of a gasoline engine.
[0014]
The housing of the injector 10 includes a valve body 12, a plate 16 and a housing body 17. The valve body 12, the plate 16, and the housing body 17 are connected by a retaining nut 18. The fuel accumulated in the delivery pipe passes through the fuel passage 100 formed in the valve body 12, the plate 16 and the housing body 17, and is supplied to the fuel reservoir 102 formed around the nozzle needle 20 as a valve member. .
An injection hole 13 is formed through the bottom of the valve body 12. A valve seat 14 on which the nozzle needle 20 can be seated is formed on the inner wall of the valve body 12. When the nozzle needle 20 is seated on the valve seat 14, fuel injection from the nozzle hole 13 is blocked.
[0015]
A control chamber 110 is formed by the end face on the side opposite to the injection hole which is one end face of the nozzle needle 20 in the reciprocating direction, the inner wall of the valve body 12 and the inner wall of the plate 16. The coil spring 22 is accommodated in the control chamber 110 and urges the nozzle needle 20 toward the valve seat 14 which is the direction of closing the nozzle hole 13.
[0016]
A housing chamber 114 and a housing chamber 120 are formed in the housing body 17. The operating member 30 is accommodated in the accommodating chamber 114 so as to be reciprocally movable, and the transmission member 40 and the drive unit 50 are accommodated in the accommodating chamber 120. As shown in FIG. 2, the operating member 30 includes an annular deformable portion 32 having elasticity, and a rigid body portion 34 that is located at the center of the actuating member 30 and is coupled to the inner periphery of the deformable portion 32 and is thicker than the deformable portion 32. Have. The actuating member 30 is formed of one member. Any material may be used as the actuating member 30 as long as it is resistant to fuel and the deformable portion 32 is deformed and the rigid portion 34 is not deformed when reciprocating with the transmission member 40. For example, the working member 30 may be manufactured by pressing a metal, or the working member 30 may be manufactured by integrally molding with a resin.
[0017]
As shown in FIG. 1, the outer peripheral edge portion of the deformable portion 32 is attached and fixed to the inner wall of the housing body 17. The rigid portion 34 is in contact with the shaft 42 of the transmission member 40 on a flat surface. The actuating member 30 liquid-tightens the storage chamber 114 on the non-contact side 116 where the rigid body portion 34 does not contact the shaft 42 of the transmission member 40 and the contact side 118 where the rigid body portion 34 contacts the shaft 42. Partitioning. The non-contact side 116 of the storage chamber 114 communicates with the control chamber 110 through the communication path 112. Since a small amount of fuel leaks as a working fluid from the sliding portion between the valve body 12 and the nozzle needle 20 to the non-contact side 116 of the storage chamber 114 and the control chamber 110, the non-contact side of the storage chamber 114 116 and the control chamber 110 are filled with fuel. In FIG. 1, the non-contact side 116 of the storage chamber 114 and the control chamber 110 are shown as a sealed space. On the other hand, a configuration may be adopted in which fuel is supplied from the fuel passage 100 to the non-contact side 116 of the storage chamber 114 and the control chamber 110 through the communication passage. The coil spring 38 urges the operating member 30 toward the transmission member 40 side.
[0018]
The transmission member 40 is installed on the actuating member 30 side of the drive unit 50 and reciprocates as the drive unit 50 expands and contracts. The leaf spring 44 biases the transmission member 40 toward the drive unit 50.
The drive unit 50 is locked to the upper inner wall of the housing body 17 shown in FIG. 1 and is electrically connected to the terminal 60. The drive unit 50 uses a piezoelectric element as a drive source, and is formed by stacking piezoelectric elements. The drive unit 50 extends toward the transmission member 40 when a voltage is applied from the terminal 60, and contracts when the voltage application is interrupted. FIG. 1 shows a state in which a voltage is applied to the driving unit 50 from the terminal 60.
[0019]
Next, the operation of the injector 10 by controlling energization to the drive unit 50 will be described.
When a voltage is applied from the terminal 60 to the drive unit 50, the drive unit 50 extends to the transmission member 40 side. The transmission member 40 moves to the operating member 30 side, which is the lower side of FIG. Since the rigid body portion 34 of the operating member 30 is in contact with the shaft 42 of the transmission member 40, the rigid body portion 34 moves to the control chamber 110 side with the same movement amount as the transmission member 40. Since the non-contact side 116 of the storage chamber 114 and the control chamber 110 are filled with fuel, when the rigid body portion 34 moves to the nozzle needle 20 side, the driving force of the driving portion 50 is transmitted to the transmission member 40 and the rigid body of the operating member 30. Part 34, the non-contact side 116 of the storage chamber 114, and the fuel charged in the control chamber 110 are applied to the nozzle needle 20 as a force toward the valve seat 14. That is, when the drive unit 50 extends, the fuel pressure in the non-contact side 116 of the storage chamber 114 and the control chamber 110 increases, and the fuel in the non-contact side 116 of the storage chamber 114 and the control chamber 110 moves toward the valve seat 14. Thus, the force received by the nozzle needle 20 increases. Therefore, the sum of the force that the nozzle needle 20 receives from the fuel in the non-contact side 116 of the storage chamber 114 and the control chamber 110 toward the valve seat 14 and the force that the nozzle needle 20 receives from the coil spring 22 toward the valve seat 14. Is greater than the force received by the fuel in the fuel reservoir 102 in the direction away from the valve seat 14. Therefore, the nozzle needle 20 is seated on the valve seat 14 and fuel injection from the nozzle hole 13 is blocked.
[0020]
When the application of the voltage to the drive unit 50 is interrupted, the drive unit 50 contracts from the state shown in FIG. 1 upward in FIG. Since the transmission member 40 is biased toward the drive unit 50 by the leaf spring 44, the transmission member 40 moves upward in FIG. 1 together with the drive unit 50. Since the rigid body portion 34 of the operating member 30 is biased toward the transmission member 40 by the biasing force of the coil spring 38, it moves together with the transmission member 40 upward in FIG. 1. That is, when the drive unit 50 contracts, the fuel pressure in the non-contact side 116 of the storage chamber 114 and the control chamber 110 decreases, and the fuel in the non-contact side 116 of the storage chamber 114 and the fuel in the control chamber 110 moves toward the valve seat 14. Thus, the force received by the nozzle needle 20 is reduced. Therefore, the sum of the force that the nozzle needle 20 receives from the fuel in the non-contact side 116 of the storage chamber 114 and the control chamber 110 toward the valve seat 14 and the force that the nozzle needle 20 receives from the coil spring 22 toward the valve seat 14. Is smaller than the force received in the direction away from the valve seat 14 by the fuel in the fuel reservoir 102. Therefore, the nozzle needle 20 is separated from the valve seat 14 and fuel is injected from the injection hole 13.
[0021]
As the drive unit 50 expands and contracts, the rigid portion 34 of the operating member 30 that is in contact with the shaft 42 of the transmission member 40 reciprocates together with the transmission member 40. The pressure receiving area where the rigid body portion 34 receives pressure in the reciprocating direction from the fuel in the non-contact side 116 of the containing chamber 114 and the control chamber 110, and the expansion / contraction amount of the driving unit 50, that is, the reciprocating movement of the transmission member 40 and the operating member 30. S1 × L1 where the amount is L1, the pressure receiving area where the nozzle needle 20 receives pressure in the reciprocating direction from the fuel in the non-contact side 116 of the storage chamber 114 and the control chamber 110, and the lift amount of the nozzle needle 20 is L2. = S2 × L2. The lift amount L2 of the nozzle needle 20 is proportional to the pressure receiving area S1 of the rigid portion 34, and increases as the pressure receiving area S1 increases. Therefore, when the pressure receiving area S2 of the nozzle needle 20 is made constant, the operating member 30 is replaced and the pressure receiving area S1 of the rigid body part 34 is changed without changing the expansion / contraction amount L1 of the drive unit 50, thereby The lift amount L2 can be changed. That is, the conversion rate of the lift amount L2 of the nozzle needle 20 with respect to the expansion / contraction amount L1 of the drive unit 50 can be changed. Thereby, the fuel injection rate or the fuel injection amount can be changed. Further, the force that the nozzle needle 20 receives from the fuel in the non-contact side 116 of the storage chamber 114 and the fuel in the control chamber 110 toward the valve seat 14 is inversely proportional to the pressure receiving area S1 of the rigid portion 34, and decreases as the pressure receiving area S1 increases. Become.
[0022]
Since the operating member 30 is attached to the housing main body 17 that forms the accommodating chamber 114 by the deformable portion 32, the housing main body 17 does not change the outer diameter of the deformable portion 32 even if the pressure receiving area of the rigid body portion 34 is changed. There is no need to change the inner diameter of the. Therefore, it is not necessary to replace the housing body 17.
[0023]
In the first embodiment, the pressure receiving area where the rigid body portion 34 receives pressure in the reciprocating direction from the fuel in the non-contact side 116 and the control chamber 110 of the storage chamber 114 is the nozzle needle 20 is not in contact with the non-contact side 116 and the control chamber 110. It is larger than the pressure receiving area that receives pressure in the reciprocating direction from the fuel. Therefore, even if the expansion / contraction amount of the drive unit 50 is small, the lift amount of the nozzle needle 20 can be increased.
[0024]
Further, since the rigid body portion 34 and the shaft 42 are in contact with each other in a plane, when the rigid body portion 34 reciprocates together with the transmission member 40, the rigid body portion 34 is not easily inclined. Since the movement amount of the rigid body portion 34 does not vary with respect to the movement amount of the transmission member 40, the lift amount of the nozzle needle 20 does not vary. Therefore, the fuel injection amount can be controlled with high accuracy.
[0025]
Furthermore, since the actuating member 30 is composed of one member, as described above, the actuating member can be easily manufactured by press working with metal or integral molding with resin.
In the first embodiment, a piezoelectric element is used as a drive source of the drive unit 50 that drives the nozzle needle 20, but a magnetostrictive element may be used as the drive source.
[0026]
(Second Example, Third Example)
A second embodiment of the present invention is shown in FIG. 3, and a third embodiment is shown in FIG.
In the operating member 70 of the second embodiment shown in FIG. 3, the deformable portion 72 and the rigid portion 74 are separate members, and the rigid portion 74 is coupled to the disc-shaped deformable portion 72 by adhesion or the like. In the operating member 80 of the third embodiment shown in FIG. 4, the deformable portion 82 and the rigid portion 84 are separate members, and an annular deformable portion 82 is joined to the outer periphery of the rigid portion 84 by welding or the like. The deformable portions 72 and 82 are attached to the inner wall of the housing body 17 that forms the accommodation chamber 114. The rigid body portions 74 and 84 are in contact with the shaft 42 of the transmission member 40.
[0027]
In the plurality of embodiments of the present invention described above, the operating member does not slide with the inner wall of the housing body 17 forming the storage chamber 114, and the operating member contacts from the non-contact side 116 of the storage chamber 114. The fuel as the working fluid is prevented from leaking to the side 118. Therefore, in order to prevent the fuel from leaking to the drive unit 50 from between the transmission member 40 and the inner wall of the housing body 17, there is no need to install a seal member such as an O-ring on the outer periphery of the transmission member 40.
[0028]
Furthermore, the lift amount of the nozzle needle 20 can be changed by replacing the operating member and changing the pressure receiving area of the rigid body portion. That is, the conversion rate of the lift amount of the nozzle needle 20 with respect to the expansion / contraction amount of the drive unit 50 can be changed. Thus, the fuel injection rate or the fuel injection amount can be easily changed simply by replacing the operating member.
Further, since the rigid body portion of the actuating member comes into contact with the shaft 42 of the transmission member 40, the rigid body portion is not easily worn or damaged.
[0029]
In the above-described embodiments, the drive unit 50 extends to cause the nozzle needle 20 to be seated on the valve seat 14 and shut off the fuel injection from the injection hole 13. On the other hand, it is also possible to adopt a configuration in which the nozzle needle 20 is seated on the valve seat 14 and the fuel injection from the injection hole 13 is shut off by the contraction of the drive unit 50.
In the above embodiments, the present invention is applied to an injector for a gasoline engine. However, the present invention can also be applied to an injector for a diesel engine.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing an injector according to a first embodiment of the present invention.
2A is a plan view showing an operating member of the first embodiment, and FIG. 2B is a sectional view taken along line BB of FIG.
FIG. 3 is a schematic cross-sectional view showing an operating member according to a second embodiment of the present invention at the same cross-sectional position as FIG.
4 is a schematic cross-sectional view showing an operating member according to a third embodiment of the present invention at the same cross-sectional position as FIG. 2 (B). FIG.
[Explanation of symbols]
10 Injector (fuel injection device)
12 Valve body (housing)
13 Injection hole 14 Valve seat 16 Plate (housing)
17 Housing body (housing)
20 Nozzle needle (valve member)
30, 70, 80 Actuating member 32, 72, 82 Deformation part 34, 74, 84 Rigid body part 40 Transmission member 50 Drive part 110 Control chamber 114 Storage chamber 116 Non-contact side of storage chamber 118 Contact side of storage chamber

Claims

A drive unit using a piezoelectric element or magnetostrictive element expands and contracts by the energization is controlled as a drive source,
A transmission member that reciprocates with expansion and contraction of the drive unit;
An actuating member that abuts the transmission member and reciprocates with the transmission member;
The actuating member is accommodated so as to be able to reciprocate, the abutting side where the actuating member abuts against the transmission member by the actuating member, and the non-abutting side where the actuating member does not abut against the transmission member; And a control chamber communicating with the non-contact side of the storage chamber is formed, and the non-contact side of the storage chamber and the control chamber are filled with a working fluid. A housing,
A valve body having a valve seat on the fuel upstream side of the nozzle hole;
By reciprocating, the fuel seat is seated on and away from the valve seat to intermittently inject fuel from the nozzle hole, and one end face in the reciprocating direction faces the control chamber, and the transmission A valve member that increases or decreases a force received toward the valve seat on the non-contact side of the storage chamber and the other side in the reciprocating direction via the working fluid of the control chamber by reciprocating the operating member together with the member; With
The actuating member is
A rigid portion located in the center of the actuating member and in contact with the transmission member and reciprocating with the transmission member;
The Rukoto outer peripheral edge portion is attached to the inner wall of the housing forming the housing chamber and coupled to the rigid portion, the partition in a liquid-tight manner the holding chamber wherein the abutting side and the non-contact side, the A deforming part that deforms by reciprocating the rigid body part; and
A fuel injection device comprising:

The pressure receiving area where the rigid body portion receives fluid pressure in the reciprocating direction from the non-contact side of the storage chamber and the working fluid of the control chamber is determined by the valve member operating on the non-contact side of the storage chamber and the control chamber. The fuel injection device according to claim 1, wherein the fuel injection device is larger than a pressure receiving area that receives a fluid pressure in a reciprocating direction from the fluid.

The fuel injection device according to claim 1, wherein the transmission member and the rigid body portion are in contact with each other on a flat surface.

4. The fuel injection device according to claim 1, wherein the deformation portion is thinner than the rigid body portion, and the actuating member is a single member.

The fuel injection device according to claim 1, wherein the deformable portion and the rigid portion are separate members.