JP2005325725A - Hydraulic transmission device, and fuel injection device - Google Patents

Hydraulic transmission device, and fuel injection device Download PDF

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JP2005325725A
JP2005325725A JP2004143125A JP2004143125A JP2005325725A JP 2005325725 A JP2005325725 A JP 2005325725A JP 2004143125 A JP2004143125 A JP 2004143125A JP 2004143125 A JP2004143125 A JP 2004143125A JP 2005325725 A JP2005325725 A JP 2005325725A
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piston
oil
diameter
valve
actuator
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JP4131251B2 (en
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Taiji Ueda
大治 植田
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Denso Corp
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Denso Corp
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M47/00—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure
    • F02M47/02—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure of accumulator-injector type, i.e. having fuel pressure of accumulator tending to open, and fuel pressure in other chamber tending to close, injection valves and having means for periodically releasing that closing pressure
    • F02M47/027—Electrically actuated valves draining the chamber to release the closing pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/0012—Valves
    • F02M63/0014—Valves characterised by the valve actuating means
    • F02M63/0015—Valves characterised by the valve actuating means electrical, e.g. using solenoid
    • F02M63/0026—Valves characterised by the valve actuating means electrical, e.g. using solenoid using piezoelectric or magnetostrictive actuators
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/0012—Valves
    • F02M63/0031—Valves characterized by the type of valves, e.g. special valve member details, valve seat details, valve housing details
    • F02M63/0033—Lift valves, i.e. having a valve member that moves perpendicularly to the plane of the valve seat
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/0012—Valves
    • F02M63/0031—Valves characterized by the type of valves, e.g. special valve member details, valve seat details, valve housing details
    • F02M63/0033—Lift valves, i.e. having a valve member that moves perpendicularly to the plane of the valve seat
    • F02M63/0035—Poppet valves, i.e. having a mushroom-shaped valve member that moves perpendicularly to the plane of the valve seat
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/0012—Valves
    • F02M63/0031—Valves characterized by the type of valves, e.g. special valve member details, valve seat details, valve housing details
    • F02M63/0045—Three-way valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
    • F02M2200/70—Linkage between actuator and actuated element, e.g. between piezoelectric actuator and needle valve or pump plunger
    • F02M2200/703—Linkage between actuator and actuated element, e.g. between piezoelectric actuator and needle valve or pump plunger hydraulic
    • F02M2200/705—Linkage between actuator and actuated element, e.g. between piezoelectric actuator and needle valve or pump plunger hydraulic with means for filling or emptying hydraulic chamber, e.g. for compensating clearance or thermal expansion
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
    • F02M2200/70—Linkage between actuator and actuated element, e.g. between piezoelectric actuator and needle valve or pump plunger
    • F02M2200/703—Linkage between actuator and actuated element, e.g. between piezoelectric actuator and needle valve or pump plunger hydraulic
    • F02M2200/705—Linkage between actuator and actuated element, e.g. between piezoelectric actuator and needle valve or pump plunger hydraulic with means for filling or emptying hydraulic chamber, e.g. for compensating clearance or thermal expansion
    • F02M2200/706—Valves for filling or emptying hydraulic chamber

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Fuel-Injection Apparatus (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic transmission device used for a common rail type fuel injection device or the like in a diesel engine to transmit displacement of an actuator, in which the whole length is shortened, and in which an injector containing the actuator is formed in compact structure. <P>SOLUTION: This hydraulic transmission device is composed of a piezo piston 62 of large diameter that is integrally displaced with a piezo stack 61, a valve piston 64 of small diameter, and an oil seal chamber 63 between them, provided in a drive part 101 of the injector 10. A cylindrical part 621 of the piezo piston 62 is engaged with a cylinder 5, and the valve piston 64 is inserted into the cylinder 5, so that the inner and outer circumferences of the cylinder 5 are set for sliding parts. Sliding length is thus secured while shortening the whole length of the device, so that the whole device is formed compact. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、油圧を介して変位を伝達する油圧伝達装置および変位を拡大して伝達する油圧伝達装置に関する。これら装置は、例えば、ディーゼルエンジンのコモンレール式燃料噴射装置において、燃料噴射を制御する制御弁の駆動部として好適に利用することができる。   The present invention relates to a hydraulic transmission device that transmits displacement via hydraulic pressure and a hydraulic transmission device that transmits displacement in an enlarged manner. These devices can be suitably used, for example, as a drive portion of a control valve that controls fuel injection in a common rail fuel injection device of a diesel engine.

ディーゼルエンジンのコモンレール式燃料噴射装置では、各気筒に共通のコモンレールを設けて高圧燃料を蓄圧し、所定のタイミングでインジェクタを駆動して各気筒に所定量の燃料を噴射するようになっている。コモンレール用のインジェクタとしては、ピエゾアクチュエータを駆動部に用いたピエゾインジェクタがあり、応答性が良いことから高度な燃料噴射制御が期待されている。ここで、ピエゾインジェクタの駆動部は、通常、ピエゾアクチュエータの変位を油圧を介して伝達する油圧伝達装置を備えており、また、ピエゾアクチュエータは変位が微小であることから、これを拡大して伝達する油圧伝達装置が提案されている。   In a common rail fuel injection device of a diesel engine, a common rail common to each cylinder is provided to accumulate high-pressure fuel, and an injector is driven at a predetermined timing to inject a predetermined amount of fuel into each cylinder. As a common rail injector, there is a piezo injector using a piezo actuator as a drive unit, and high fuel injection control is expected because of its high responsiveness. Here, the drive unit of the piezo injector is usually provided with a hydraulic transmission device that transmits the displacement of the piezo actuator via hydraulic pressure. Since the piezo actuator has a very small displacement, it is enlarged and transmitted. A hydraulic transmission device has been proposed.

変位を拡大して伝達する油圧伝達装置の従来技術として、例えば特許文献１〜３が知られ、大径のピストンと小径のピストンを段差のあるシリンダ内に収め、断面積の異なるピストン間で油圧伝達を行うことにより、ピエゾアクチュエータの変位を拡大する機構を構成している。
特開２００２−１１５６１７号公報 米国特許出願公開第２００２−０１０４９７６号明細書 米国特許出願公開第２００３−０１５５５４０号明細書 For example, Patent Documents 1 to 3 are known as conventional hydraulic transmission devices that transmit displacement in an enlarged manner. A large-diameter piston and a small-diameter piston are accommodated in a stepped cylinder, and hydraulic pressure is obtained between pistons having different cross-sectional areas. By performing the transmission, a mechanism for enlarging the displacement of the piezo actuator is configured.
JP 2002-115617 A US Patent Application Publication No. 2002-0104976 US Patent Application Publication No. 2003-0155540

変位を拡大して伝達する油圧伝達装置を備えるピエゾインジェクタの一例を図５に示す。図５において、ピエゾスタック６１の下方には大径のピエゾピストン６２と小径のバルブピストン６４が同軸に配設され、シリンダ５内を摺動するようになっている。シリンダ５内には、ピエゾピストン６２とバルブピストン６４の間の段差部に油密室６３が設けられる。バルブピストン６４は、ノズルニードル３に背圧を作用させる制御室４と高圧通路１５、低圧通路１６の間を開閉する３方弁のバルブニードル１に当接している。図は、ピエゾスタック６１に通電せず、バルブニードル１が第１シート２２に着座する上端位置にある状態を示し、制御室４は、通路２５、バルブ室２１、オリフィス２４を介して高圧通路１５と連通するとともに、サブオリフィス４１を介して高圧通路１５と連通するために、高圧となっている。この時、ノズルニードル３は下端位置にあって噴孔３４は閉鎖されている。   FIG. 5 shows an example of a piezo injector provided with a hydraulic transmission device that expands and transmits displacement. In FIG. 5, a large-diameter piezo piston 62 and a small-diameter valve piston 64 are coaxially arranged below the piezo stack 61 so as to slide in the cylinder 5. In the cylinder 5, an oil-tight chamber 63 is provided at a step portion between the piezo piston 62 and the valve piston 64. The valve piston 64 is in contact with the valve needle 1 of a three-way valve that opens and closes between the control chamber 4 that applies back pressure to the nozzle needle 3, the high pressure passage 15, and the low pressure passage 16. The figure shows a state in which the piezo stack 61 is not energized and the valve needle 1 is in the upper end position where the first needle 22 is seated. The control chamber 4 is connected to the high-pressure passage 15 via the passage 25, the valve chamber 21, and the orifice 24. And the high pressure passage 15 via the sub-orifice 41, the pressure is high. At this time, the nozzle needle 3 is at the lower end position and the nozzle hole 34 is closed.

上記構成において、ピエゾスタック６１に通電するとピエゾピストン６２が下方に変位し、油密室６３の圧力上昇に伴ってバルブピストン６４が押し下げられる。この時、ピエゾピストン６２とバルブピストン６４の径差に応じて変位が拡大され、バルブニードル１は第１シート２２から離座した後、さらに第２シート２３に着座するまで下方に移動する。すると、制御室４と高圧通路１５の連通が遮断され、低圧通路１６と連通するために、制御室４が低圧となり、ノズルニードル３がリフトを開始し、燃料溜まり室３２とサック部３３が連通して噴孔３４から燃料が噴射される。   In the above configuration, when the piezo stack 61 is energized, the piezo piston 62 is displaced downward, and the valve piston 64 is pushed down as the pressure in the oil tight chamber 63 increases. At this time, the displacement is expanded according to the difference in diameter between the piezo piston 62 and the valve piston 64, and the valve needle 1 moves downward until it is seated on the second seat 23 after being separated from the first seat 22. Then, the communication between the control chamber 4 and the high pressure passage 15 is interrupted and the communication with the low pressure passage 16 is established, so that the control chamber 4 becomes low pressure, the nozzle needle 3 starts to lift, and the fuel reservoir chamber 32 and the sack portion 33 communicate with each other. Then, fuel is injected from the injection hole 34.

しかしながら、上記構成では、ピエゾピストン６２、バルブピストン６４ともにある程度の摺動長を必要とするため、油圧伝達装置の全長が長くなる。その結果、インジェクタの全長が長くなってしまうという問題が生じている。   However, in the above configuration, both the piezo piston 62 and the valve piston 64 require a certain amount of sliding length, so that the total length of the hydraulic transmission device becomes long. As a result, there arises a problem that the total length of the injector becomes long.

そこで、本発明の目的は、ディーゼルエンジンのコモンレール式燃料噴射装置等に使用されるアクチュエータの変位を伝達する装置の全長を短くすること、それによりアクチュエータを内蔵するインジェクタをコンパクトな構造とすることにある。   Accordingly, an object of the present invention is to shorten the overall length of a device that transmits the displacement of an actuator used in a common rail fuel injection device or the like of a diesel engine, thereby making the injector incorporating the actuator a compact structure. is there.

請求項１の発明は、通電により変位を発生するアクチュエータと、アクチュエータと一体に変位する第１ピストンと、第１ピストンと油密室を挟んで対向する第２ピストンを有し、アクチュエータの変位を油圧を介して第２ピストンに伝達する油圧伝達装置であり、第１および第２ピストンの一方を一端閉鎖の筒状として、該筒状部をハウジングに固定される筒状シリンダに外挿する。一方、筒状シリンダに第１および第２ピストンのもう一方を内挿して、第１および第２ピストンを筒状シリンダの内外周面に対して摺動自在とし、さらに筒状部と筒状シリンダと第１および第２ピストンのもう一方とで囲まれる空間に作動油を充填して上記油密室としている。   The invention of claim 1 has an actuator that generates displacement when energized, a first piston that is displaced integrally with the actuator, and a second piston that faces the first piston across an oil-tight chamber, and the displacement of the actuator is hydraulic. Is a hydraulic transmission device that transmits to the second piston via a cylinder, and one of the first and second pistons is formed in a cylindrical shape with one end closed, and the cylindrical portion is extrapolated to a cylindrical cylinder fixed to the housing. On the other hand, the other of the first and second pistons is inserted into the cylindrical cylinder so that the first and second pistons can slide with respect to the inner and outer peripheral surfaces of the cylindrical cylinder, and the cylindrical portion and the cylindrical cylinder And the other of the first and second pistons is filled with hydraulic oil to form the oil tight chamber.

上記構成によれば、固定部材である上記筒状シリンダの内外周に、可動部材である上記第１、第２ピストンを配置し、摺動範囲が重なるように構成したので、各ピストンの摺動長を確保したまま、装置の全長（軸方向長）を短くできる。従って、第１、第２ピストンを一直線上に配置した従来構造に比べて、油圧伝達装置の全長が短くなるので、これを用いたインジェクタ等をコンパクトな構造とすることができる。   According to the above configuration, the first and second pistons that are movable members are arranged on the inner and outer circumferences of the cylindrical cylinder that is a fixed member so that the sliding ranges overlap. The overall length (axial length) of the device can be shortened while ensuring the length. Therefore, compared to the conventional structure in which the first and second pistons are arranged in a straight line, the total length of the hydraulic transmission device is shortened, so that an injector or the like using the hydraulic transmission device can have a compact structure.

請求項２の発明は、通電により変位を発生するアクチュエータと、アクチュエータと一体に変位する大径ピストンと、大径ピストンと油密室を挟んで対向する小径ピストンを有し、アクチュエータの変位を油圧を介して拡大して小径ピストンに伝達する油圧伝達装置であり、大径ピストンを一端閉鎖の筒状として、該筒状部をハウジングに固定される筒状シリンダに外挿する。一方、上記筒状シリンダに上記小径ピストンを内挿して、上記大径および小径ピストンを上記筒状シリンダの外周面および内周面に対してそれぞれ摺動自在とし、さらに上記大径ピストンの筒状部と上記筒状シリンダと上記小径ピストンとで囲まれる空間に作動油を充填して上記油密室としている。   The invention of claim 2 has an actuator that generates displacement when energized, a large-diameter piston that is displaced integrally with the actuator, and a small-diameter piston that faces the large-diameter piston with an oil-tight chamber interposed therebetween. The large-diameter piston has a cylindrical shape with one end closed, and the cylindrical portion is extrapolated to a cylindrical cylinder fixed to the housing. On the other hand, the small-diameter piston is inserted into the cylindrical cylinder so that the large-diameter and small-diameter pistons can slide with respect to the outer peripheral surface and the inner peripheral surface of the cylindrical cylinder, respectively, and the cylindrical shape of the large-diameter piston The oil-tight chamber is formed by filling the space surrounded by the portion, the cylindrical cylinder, and the small-diameter piston with hydraulic oil.

上記構成によれば、固定部材である筒状シリンダの内外周に、可動部材である大径、小径ピストンを配置し、摺動範囲が重なるように構成したので、各ピストンの摺動長を確保したまま、装置の全長（軸方向長）を短くできる。従って、大径、小径ピストンを一直線上に配置した従来構造に比べて、油圧伝達装置の全長が短くなり、さらに、径の異なる大径ピストンと小径ピストンを組み合わせることで、大径ピストンの変位を拡大して小径ピストンに伝達することができる。よって、この油圧伝達装置をインジェクタ等に適用すれば、アクチュエータの変位を効果的に拡大して、必要な変位を確保し、しかもコンパクトな構造とすることができる。   According to the above configuration, the large and small diameter pistons that are movable members are arranged on the inner and outer periphery of the cylindrical cylinder that is the fixed member, and the sliding ranges are overlapped, so that the sliding length of each piston is ensured. In this way, the overall length (axial length) of the device can be shortened. Therefore, compared to the conventional structure in which large and small diameter pistons are arranged in a straight line, the overall length of the hydraulic transmission device is shortened, and the displacement of the large diameter piston can be reduced by combining large and small diameter pistons with different diameters. It can be enlarged and transmitted to a small-diameter piston. Therefore, if this hydraulic transmission device is applied to an injector or the like, the displacement of the actuator can be effectively enlarged, the necessary displacement can be ensured, and a compact structure can be achieved.

請求項３の発明は、上記一端閉鎖の筒状とした第１、第２ピストンまたは大径ピストンの、閉鎖端部と筒状部とを別部材にて構成する。   According to a third aspect of the present invention, the closed end portion and the cylindrical portion of the first, second piston or large-diameter piston having the one end closed cylindrical shape are configured as separate members.

上記一端閉鎖の筒状ピストンを複数部材で構成することで、閉鎖端側の筒部内の加工が容易になり、安価に製造できる。   By forming the cylindrical piston closed at one end with a plurality of members, processing in the cylindrical portion on the closed end side becomes easy and can be manufactured at low cost.

請求項４の発明は、上記各請求項の構成における油密室と、低圧部とを連通する連通路を設け、該連通路に、油密室の圧力が所定圧を下回った時に油密室に作動油を流入させるチェック弁を設けている。   According to a fourth aspect of the present invention, there is provided a communication passage that communicates the oil-tight chamber and the low-pressure portion in the configuration of each of the above-mentioned claims, and the hydraulic oil is supplied to the oil-tight chamber when the pressure in the oil-tight chamber falls below a predetermined pressure. A check valve is provided for inflow.

上記構成において、油密室の圧力が所定圧を下回ると、チェック弁が開いて油密室に作動油を流入させる。これにより、油密室からリークした作動油の補充が容易にできるので、油密室の油圧を保持して変位の伝達を効率よく行うことができる。   In the above configuration, when the pressure in the oil tight chamber falls below a predetermined pressure, the check valve is opened and hydraulic oil flows into the oil tight chamber. Thereby, since the hydraulic oil leaking from the oil tight chamber can be easily replenished, displacement can be efficiently transmitted while maintaining the oil pressure of the oil tight chamber.

請求項５の発明は、上記各請求項の構成におけるアクチュエータをピエゾアクチュエータとする。   According to a fifth aspect of the present invention, the actuator in the configuration of each of the above claims is a piezo actuator.

変位を発生する部材としては、ピエゾ素子を用いたアクチュエータのように、発生力が大きく変位が小さいアクチュエータを用いると、コンパクトな構成で変位を効率よく伝達することができるので、本発明を適用する効果が高い。   As the member that generates the displacement, if an actuator having a large generated force and a small displacement such as an actuator using a piezo element is used, the displacement can be efficiently transmitted with a compact configuration, and thus the present invention is applied. High effect.

請求項６の発明は、上記請求項１から５の油圧伝達装置をノズルニードルの開閉を制御する制御弁の駆動部として備える燃料噴射装置であり、ノズルニードルに閉弁方向の圧力を作用させる制御室を設けている。この装置では、駆動部を構成する油圧伝達装置の小径ピストンによって、制御弁を開閉駆動することにより、制御室の圧力を増減させてノズルニードルを昇降させる。   A sixth aspect of the present invention is a fuel injection device including the hydraulic pressure transmission device according to any one of the first to fifth aspects as a drive portion of a control valve that controls opening and closing of the nozzle needle, and controls the pressure applied to the nozzle needle in the valve closing direction. There is a room. In this apparatus, the control needle is opened and closed by a small-diameter piston of a hydraulic transmission device that constitutes a drive unit, whereby the pressure in the control chamber is increased and decreased to raise and lower the nozzle needle.

ノズルニードルの背圧を制御弁で制御して燃料噴射を行う燃料噴射装置において、制御弁の駆動部に上記油圧伝達装置を用いると、アクチュエータを大型化することなく必要な変位を確保することができるので、小型でエネルギー効率の高い燃料噴射装置が得られる。   In a fuel injection device that performs fuel injection by controlling the back pressure of the nozzle needle with a control valve, if the hydraulic transmission device is used in the drive portion of the control valve, the required displacement can be ensured without increasing the size of the actuator. As a result, a small and highly energy efficient fuel injection device can be obtained.

以下、図面に基づいて本発明の第１の実施形態を説明する。図１は本発明を適用した燃料噴射装置のインジェクタ１０構成を示す図で、変位を拡大する油圧伝達装置としてのピエゾ駆動部１０１を内蔵している。本実施形態では、ディーゼルエンジンのコモンレール式燃料噴射装置への適用例として説明し、エンジンの各気筒に対応して設けられるインジェクタ１０は、コモンレールから燃料（ここでは軽油）の供給を受けるようになっている。コモンレールには高圧サプライポンプにより圧送される燃料が噴射圧力に相当する所定の高圧で蓄えられる。   Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a configuration of an injector 10 of a fuel injection device to which the present invention is applied, and incorporates a piezo drive unit 101 as a hydraulic transmission device that expands displacement. In this embodiment, an example of application to a common rail fuel injection device of a diesel engine will be described, and an injector 10 provided corresponding to each cylinder of the engine is supplied with fuel (here, light oil) from the common rail. ing. In the common rail, fuel pumped by a high-pressure supply pump is stored at a predetermined high pressure corresponding to the injection pressure.

図１において、インジェクタ１０は、ピエゾスタック６１を有するピエゾ駆動部１０１（上半部）と、ノズルニードル３を有するノズル部１０３（下端部）と、３方弁構造の制御弁部１０２（中間部）とからなる。インジェクタ１０は、図略の燃焼室壁に取付けられるハウジング１４を有し、ハウジング１４内には上記各部１０１〜１０３の構成部品が収納されるとともに、図略のコモンレールに連通する高圧通路１５、図略の燃料タンクに至るドレーン通路へ連通する低圧通路１６等の通路が形成される。   In FIG. 1, an injector 10 includes a piezo driving unit 101 (upper half) having a piezo stack 61, a nozzle unit 103 (lower end) having a nozzle needle 3, and a control valve unit 102 (intermediate part) having a three-way valve structure. ). The injector 10 has a housing 14 attached to a combustion chamber wall (not shown). The housing 14 accommodates the components of the above-described parts 101 to 103, and is connected to a common rail (not shown). A passage such as a low-pressure passage 16 that communicates with a drain passage leading to a substantially fuel tank is formed.

ノズル部１０３は、ハウジング１４の下端部内に形成した縦穴３１に、段付きのノズルニードル３を摺動自在に保持しており、ノズルニードル３の下半小径部の外周には環状の油溜まり室３２が形成されている。油溜まり室３２は常時高圧通路１５と連通しコモンレールからの高圧燃料が供給されている。縦穴３１の下方には、これに連なってサック部３３が形成され、サック部３３形成壁を貫通して燃料噴射用の噴孔３４が形成される。   The nozzle portion 103 holds the stepped nozzle needle 3 in a vertical hole 31 formed in the lower end portion of the housing 14 so as to be slidable, and an annular oil sump chamber is provided on the outer periphery of the lower half small diameter portion of the nozzle needle 3. 32 is formed. The oil sump chamber 32 is always in communication with the high pressure passage 15 and is supplied with high pressure fuel from the common rail. Below the vertical hole 31, a sack portion 33 is formed continuously therewith, and a fuel injection nozzle hole 34 is formed through the sack portion 33 forming wall.

ノズルニードル３は下端位置にある時に、円錐形の先端部がサック部３３と縦穴３１の境界部に設けたシート３５に着座し、サック部３３を閉じて油溜まり室３２から噴孔３４への燃料供給を遮断する。ノズルニードル３が上昇してシート３５から離座し、サック部３３を開くと燃料が噴射される。   When the nozzle needle 3 is in the lower end position, the conical tip is seated on a seat 35 provided at the boundary between the sack portion 33 and the vertical hole 31, the sack portion 33 is closed, and the oil reservoir chamber 32 is connected to the nozzle hole 34. Shut off the fuel supply. When the nozzle needle 3 is lifted and separated from the seat 35 and the sack portion 33 is opened, fuel is injected.

ノズルニードル３の上端面および縦穴３１の壁面により画成される空間は、ノズルニードル３に背圧を与える制御室４となる。制御室４には、後述する背圧制御部１０２のバルブ室２１およびオリフィス２４を介して、また、高圧通路１５からサブオリフィス４１を介して、制御油としての燃料が導入されており、ノズルニードル３の背圧を発生している。この背圧はノズルニードル３に下向きに作用して、制御室４内に収納されたスプリング４２とともにノズルニードル３を着座方向に付勢する。一方、油溜まり室３２の高圧燃料がノズルニードル３の段差面に上向きに作用しノズルニードル３を離座方向に付勢している。なお、サブオリフィス４１は、噴射開始時に制御室４の圧力降下を緩和し、噴射停止時に制御室４の圧力上昇を促進して、ノズルニードル３の開閉速度を調整する機能を有する。   A space defined by the upper end surface of the nozzle needle 3 and the wall surface of the vertical hole 31 serves as a control chamber 4 that applies back pressure to the nozzle needle 3. Fuel as control oil is introduced into the control chamber 4 through a valve chamber 21 and an orifice 24 of the back pressure control unit 102, which will be described later, and from the high-pressure passage 15 through a sub-orifice 41. 3 back pressure is generated. This back pressure acts downward on the nozzle needle 3 and urges the nozzle needle 3 in the seating direction together with the spring 42 housed in the control chamber 4. On the other hand, the high-pressure fuel in the oil sump chamber 32 acts upward on the step surface of the nozzle needle 3 to urge the nozzle needle 3 in the seating direction. The sub-orifice 41 has a function of adjusting the opening / closing speed of the nozzle needle 3 by reducing the pressure drop in the control chamber 4 at the start of injection and promoting the pressure increase in the control chamber 4 at the stop of injection.

３方弁構造の制御弁部１０２は、バルブニードル１の大径の弁部１１が、バルブ室２１天井面の３方弁第１シ−ト２２または底面の３方弁第２シ−ト２３に選択的に着座するようになっている。第１シート２２と第２シート２３は、バルブ室２１天井面と底面中央部の対向位置に設けられ、第１シート２２は低圧部２６を介して低圧通路１６と連通し、第２シート２３は通路２５を介して高圧通路１５と連通している。バルブ室２１は、オリフィス２４を介してノズル部１０３の制御室４と常時連通している。   The control valve portion 102 of the three-way valve structure is such that the large-diameter valve portion 11 of the valve needle 1 is a three-way valve first sheet 22 on the ceiling surface of the valve chamber 21 or a three-way valve second sheet 23 on the bottom surface. To sit selectively. The first seat 22 and the second seat 23 are provided at opposing positions of the ceiling surface and the bottom center portion of the valve chamber 21, the first seat 22 communicates with the low pressure passage 16 via the low pressure portion 26, and the second seat 23 is The high pressure passage 15 communicates with the passage 25. The valve chamber 21 is always in communication with the control chamber 4 of the nozzle portion 103 via the orifice 24.

バルブニードル１は圧力バランス構造で、上端部が大径の弁部１１となっており、下端部は第２シート２３に続くシリンダ２７内を摺動する摺動部１３となっている。中間部は、バルブ室２１内の弁部１１と摺動部１３をつなぐ細径部１２となっており、この細径部１２とシリンダ２７内の間に形成される環状空間に、高圧通路１５へ至る通路２５が開口している。   The valve needle 1 has a pressure balance structure, the upper end portion is a large-diameter valve portion 11, and the lower end portion is a sliding portion 13 that slides in the cylinder 27 following the second seat 23. The intermediate portion is a small-diameter portion 12 that connects the valve portion 11 in the valve chamber 21 and the sliding portion 13, and the high-pressure passage 15 is formed in an annular space formed between the small-diameter portion 12 and the cylinder 27. A passage 25 leading to is opened.

バルブニードル１が上端位置にある時には、弁部１１のフラットな頂面が、バルブ室２１天井面の第１シート２２に着座して低圧通路１６との連通を遮断する。バルブニードル１が下端位置にある時には、弁部１１の下部テーパ面が、バルブ室２１底面の第２シート２３に着座して、高圧通路１５との連通を遮断する。バルブニードル１は、ピエゾ駆動部１０１により押圧駆動されることで上下動するようになっており、作動状態が切り換わるのに伴い、バルブ室２１に連通する制御室４の圧力、すなわちノズルニードル３の背圧が増減する。   When the valve needle 1 is at the upper end position, the flat top surface of the valve portion 11 is seated on the first seat 22 on the ceiling surface of the valve chamber 21 to block communication with the low pressure passage 16. When the valve needle 1 is in the lower end position, the lower taper surface of the valve portion 11 is seated on the second seat 23 on the bottom surface of the valve chamber 21 to block communication with the high pressure passage 15. The valve needle 1 is moved up and down by being pressed by the piezo drive unit 101. As the operating state is switched, the pressure in the control chamber 4 communicating with the valve chamber 21, that is, the nozzle needle 3 is switched. Back pressure increases or decreases.

バルブニードル１の摺動部１３下方には、バルブスプリング１７が収容されて、バルブニードル１を上方に付勢している。摺動部１３下方のシリンダ２７側壁には、低圧部２６に至る連通路が開口して、バルブニードル１の下方への移動が抑制されないようにしている。この構成により、噴射開始時に弁部１１を第１シート２２から速やかに離座させることができる。   A valve spring 17 is accommodated below the sliding portion 13 of the valve needle 1 to urge the valve needle 1 upward. On the side wall of the cylinder 27 below the sliding portion 13, a communication path reaching the low pressure portion 26 is opened so that the downward movement of the valve needle 1 is not suppressed. With this configuration, the valve portion 11 can be quickly separated from the first seat 22 at the start of injection.

ピエゾ駆動部１０１は、ピエゾアクチュエータとしてのピエゾスタック６１を用いて構成される。ピエゾスタック６１は、バルブ室２１の上方に形成した縦穴内に収容され、その下方に、大径ピストン（第１ピストン）であるピエゾピストン６２、小径ピストン（第２ピストン）であるバルブピストン６４を同軸に配設してなる。ピエゾスタック６１はＰＺＴ等の圧電セラミック層と電極層を交互に積層した公知の構造を有し、積層方向（上下方向）を伸縮方向として、図示しない駆動回路により充放電されるようになっている。ピエゾピストン６２とバルブピストン６４は、縦穴内に固定した筒状シリンダ５に摺動自在に支持され、ピエゾピストン６２とバルブピストン６４の間には油密室６３が形成される。これらピストン６２、６４と油密室６３の構成は、本発明の特徴部分であり、以下に詳細を示す。   The piezo drive unit 101 is configured using a piezo stack 61 as a piezo actuator. The piezo stack 61 is accommodated in a vertical hole formed above the valve chamber 21, and a piezo piston 62 that is a large-diameter piston (first piston) and a valve piston 64 that is a small-diameter piston (second piston) are disposed below the piezo stack 61. It is arranged coaxially. The piezo stack 61 has a known structure in which piezoelectric ceramic layers such as PZT and electrode layers are alternately stacked, and is charged and discharged by a drive circuit (not shown) with the stacking direction (vertical direction) as an expansion / contraction direction. . The piezo piston 62 and the valve piston 64 are slidably supported by the cylindrical cylinder 5 fixed in the vertical hole, and an oil tight chamber 63 is formed between the piezo piston 62 and the valve piston 64. The configuration of the pistons 62 and 64 and the oil-tight chamber 63 is a characteristic part of the present invention and will be described in detail below.

ピエゾスタック６１の下端面は縦穴内に摺動自在に設けたピストン部材６６に支持され、該ピストン部材６６の下方にピエゾピストン６２が密接配置してある。図２のように、ピエゾピストン６２は上端閉鎖の筒状で、該筒状部６２１をシリンダ５の筒状部５１に上方から外挿することにより、筒状部５１外周面に対して摺動自在となっている。シリンダ５は、筒状部５１の下端外方に張り出すフランジ部５２にてハウジング１４に固定され、該フランジ部５２とピエゾピストン６２の上端大径部６２２の間に、ピエゾスプリング６５が設けられて、ピエゾピストン６２およびピストン部材６６を介してピエゾスタック６１に一定の初期荷重を印加している。これにより、ピエゾピストン６２はピエゾスタック６１の伸縮に伴い、一体に上下動する。ピエゾスプリング６５は、コイルバネでもスリットスプリングでもよい。   The lower end surface of the piezo stack 61 is supported by a piston member 66 slidably provided in the vertical hole, and the piezo piston 62 is closely disposed below the piston member 66. As shown in FIG. 2, the piezo piston 62 has a cylindrical shape with a closed top end, and slides with respect to the outer peripheral surface of the cylindrical portion 51 by extrapolating the cylindrical portion 621 from above to the cylindrical portion 51 of the cylinder 5. It is free. The cylinder 5 is fixed to the housing 14 by a flange portion 52 projecting outward from the lower end of the cylindrical portion 51, and a piezo spring 65 is provided between the flange portion 52 and the upper end large diameter portion 622 of the piezo piston 62. Thus, a certain initial load is applied to the piezo stack 61 via the piezo piston 62 and the piston member 66. As a result, the piezo piston 62 moves up and down as the piezo stack 61 expands and contracts. The piezo spring 65 may be a coil spring or a slit spring.

バルブピストン６４は柱状で、シリンダ５の筒状部５１に下方から内挿され、筒状部５１内周面に対して摺動自在となっている。バルブピストン６４のピン状の下端部６４１は、３方弁第１シート２２方向へ延び、バルブ室２１内のバルブニードル１頂面に当接している。バルブピストン６４の中間部外周にはフランジ６４２が形成され、該フランジ６４２上に支持されるバルブピストンプリセットスプリング５３によってバルブピストン６４が下方に付勢されている。ピエゾピストン６２の筒状部６２１とシリンダ５の筒状部５１とバルブピストン６４とで囲まれる空間には、作動油としての燃料が充填されて油密室６３を形成している。   The valve piston 64 is columnar, is inserted into the cylindrical portion 51 of the cylinder 5 from below, and is slidable with respect to the inner peripheral surface of the cylindrical portion 51. A pin-like lower end portion 641 of the valve piston 64 extends toward the three-way valve first seat 22 and is in contact with the top surface of the valve needle 1 in the valve chamber 21. A flange 642 is formed on the outer periphery of the intermediate portion of the valve piston 64, and the valve piston 64 is biased downward by a valve piston preset spring 53 supported on the flange 642. A space surrounded by the cylindrical portion 621 of the piezo piston 62, the cylindrical portion 51 of the cylinder 5 and the valve piston 64 is filled with fuel as hydraulic oil to form an oil tight chamber 63.

従って、ピエゾスタック６１が伸長してピエゾピストン６２を下方に押圧すると、その押圧力が油密室６３の燃料を介してバルブピストン６４に伝達され、油圧伝達装置として機能する。さらに、本実施形態では、大径のピエゾピストン６２に対し小径のバルブピストン６４を用いたので、ピエゾピストン６２の筒状部６２１内径とバルブピストン６４の外径の差（摺動径差）に応じて、ピエゾスタック６１の変位を拡大して伝達する油圧伝達装置として機能する。   Accordingly, when the piezo stack 61 extends and presses the piezo piston 62 downward, the pressing force is transmitted to the valve piston 64 via the fuel in the oil-tight chamber 63 and functions as a hydraulic transmission device. Further, in this embodiment, since the small-diameter valve piston 64 is used with respect to the large-diameter piezo piston 62, the difference between the inner diameter of the cylindrical portion 621 of the piezo piston 62 and the outer diameter of the valve piston 64 (sliding diameter difference). Accordingly, it functions as a hydraulic transmission device that enlarges and transmits the displacement of the piezo stack 61.

次に、上記各実施形態におけるインジェクタ１０の作動を説明する。まず、第１の実施形態において、図１、２はピエゾスタック６１が放電状態で縮小している状態を示しており、バルブニードル１は、バルブ室２１内の燃料圧力とスプリング１７力により上方に付勢されて、弁部１１が第１シート２２に着座している。第１シート２２に対向する第２シート２３は開弁している。従って、制御室４は、オリフィス２４、バルブ室２１、第２シート２３を介して高圧通路１５に連通するとともに、サブオリフィス４１を介して高圧通路１５に連通し、高圧通路１５から流入する燃料により高圧となっている。この燃料圧力とスプリング４２力によりノズルニードル３はシート３５に着座しており、燃料噴射はなされない。   Next, the operation of the injector 10 in each of the above embodiments will be described. First, in the first embodiment, FIGS. 1 and 2 show a state in which the piezo stack 61 is contracted in a discharged state, and the valve needle 1 is moved upward by the fuel pressure in the valve chamber 21 and the spring 17 force. The valve portion 11 is seated on the first seat 22 by being biased. The second sheet 23 facing the first sheet 22 is opened. Therefore, the control chamber 4 communicates with the high-pressure passage 15 through the orifice 24, the valve chamber 21, and the second seat 23, and communicates with the high-pressure passage 15 through the sub-orifice 41. High pressure. The nozzle needle 3 is seated on the seat 35 by the fuel pressure and the spring 42 force, and fuel injection is not performed.

この状態から、ピエゾスタック６１に通電すると、ピエゾスタック６１が充填されて伸長する。これに伴い、ピエゾピストン６２が下方に移動して油密室６３の作動油（ここでは軽油）が圧縮される。この作動油の圧力でバルブピストン６４が下方に移動しバルブニードル１を押し下げると、弁部１１が第１シート２２から離座し、さらに下方変位して第２シート２３に着座する。これにより、制御室４がバルブ室２１、第１シート２２を介して低圧通路１６に連通し、制御室４の圧力が降下して、ノズルニードル３の下向きの付勢力が上向きの付勢力を下回ると、ノズルニードル３が離座して燃料噴射が開始される。   From this state, when the piezo stack 61 is energized, the piezo stack 61 is filled and extended. Along with this, the piezo piston 62 moves downward and the hydraulic oil (light oil here) in the oil-tight chamber 63 is compressed. When the valve piston 64 moves downward by the pressure of the hydraulic oil and pushes down the valve needle 1, the valve portion 11 is separated from the first seat 22, further displaced downward, and is seated on the second seat 23. As a result, the control chamber 4 communicates with the low pressure passage 16 via the valve chamber 21 and the first seat 22, the pressure in the control chamber 4 drops, and the downward biasing force of the nozzle needle 3 is less than the upward biasing force. Then, the nozzle needle 3 is separated and fuel injection is started.

次に、ピエゾスタック６１を再び放電させると、ピエゾスタック６１が収縮してピエゾピストン６２が上方へ移動し、油密室６３の圧力が降下してバルブニードル１の押し下げ力が解除される。よって、制御室４にオリフィス２４、サブオリフィス４１を介して流入する高圧燃料により、制御室４圧力が再び上昇し、ニードル３が着座して噴射が終了する。   Next, when the piezo stack 61 is discharged again, the piezo stack 61 contracts, the piezo piston 62 moves upward, the pressure in the oil-tight chamber 63 drops, and the pressing force of the valve needle 1 is released. Therefore, the high pressure fuel flowing into the control chamber 4 via the orifice 24 and the sub-orifice 41 raises the control chamber 4 pressure again, the needle 3 is seated, and the injection is finished.

本実施形態のように、アクチュエータとしてピエゾスタック６１を用いた場合には、変位が非常に小さいため、大径のピエゾピストン６２と小径のバルブピストン６４を組み合わせた油圧伝達装置を用いると、効率よく動力を伝達することができる。その場合、上記構成のように筒状シリンダ５の外周側をピエゾピストン６２が、内周側をバルブピストン６４が摺動する構成とし、シリンダ５の内周、外周をともに摺動部として用いると、ピストン摺動長を確保しながらピエゾ駆動部１０１（油圧伝達装置）の全長を大幅に短縮することができる。よって、制御弁部１０２の駆動に十分な変位を確保することができ、コンパクトで高応答かつ高性能なインジェクタ１０を実現できる。   As in this embodiment, when the piezo stack 61 is used as an actuator, the displacement is very small. Therefore, when a hydraulic transmission device that combines a large-diameter piezo piston 62 and a small-diameter valve piston 64 is used, it is efficient. Power can be transmitted. In that case, when the piezo piston 62 slides on the outer peripheral side of the cylindrical cylinder 5 and the valve piston 64 slides on the inner peripheral side as in the above configuration, both the inner and outer periphery of the cylinder 5 are used as sliding portions. The overall length of the piezo drive unit 101 (hydraulic transmission device) can be greatly shortened while ensuring the piston sliding length. Therefore, a sufficient displacement for driving the control valve unit 102 can be secured, and a compact, high-response and high-performance injector 10 can be realized.

図３は、本発明の第２の実施形態であり、ピエゾ駆動部１０１（油圧伝達装置）の他の構成例を示す。インジェクタ１０の全体構成および基本作動は上記第１の実施形態と同様であり、説明を省略する。図３のように、本実施形態では、筒状シリンダ５の下端部を、バルブ室２１が形成されるハウジング１４の上面に設けた凹部に嵌合固定し、外周のフランジ部５２がハウジング１４の上面に当接支持される構成とする。シリンダ５の段付に拡径した下半部内は低圧室５５としてあり、低圧室５５側壁に設けた連通孔５４によって低圧部２６に連通している。   FIG. 3 shows another example of the configuration of the piezo drive unit 101 (hydraulic transmission device) according to the second embodiment of the present invention. The overall configuration and basic operation of the injector 10 are the same as those in the first embodiment, and a description thereof will be omitted. As shown in FIG. 3, in the present embodiment, the lower end portion of the cylindrical cylinder 5 is fitted and fixed to a recess provided on the upper surface of the housing 14 in which the valve chamber 21 is formed, and the outer peripheral flange portion 52 is formed on the housing 14. It is set as the structure contacted and supported by the upper surface. The inside of the lower half of the cylinder 5 whose diameter has been expanded is a low-pressure chamber 55, which communicates with the low-pressure portion 26 through a communication hole 54 provided in the side wall of the low-pressure chamber 55.

従って、バルブニードル１が３方弁第１シート２２を開放すると、バルブ室２１から第１シート２２、低圧室５５、連通孔５４を経て低圧部２６に燃料が流出する。また、バルブピストン６４の下端部６４３は、下方に向けて縮径するテーパ状に形成され、該テーパ部の上端面とシリンダ５の段付部との間にバルブセットスプリング５３が配設される。   Therefore, when the valve needle 1 opens the three-way valve first seat 22, the fuel flows out from the valve chamber 21 to the low pressure portion 26 through the first seat 22, the low pressure chamber 55, and the communication hole 54. Further, the lower end portion 643 of the valve piston 64 is formed in a tapered shape with a diameter decreasing downward, and a valve set spring 53 is disposed between the upper end surface of the tapered portion and the stepped portion of the cylinder 5. .

本実施形態によっても、上記第１の実施形態と同様の効果が得られる。このように、筒状シリンダ５の内外周にピエゾピストン６２およびバルブピストン６４が摺動する構成であれば、各部材の形状や固定方法等は、特に制限されない。   Also according to this embodiment, the same effect as the first embodiment can be obtained. Thus, as long as the piezo piston 62 and the valve piston 64 slide on the inner and outer circumferences of the cylindrical cylinder 5, the shape and fixing method of each member are not particularly limited.

図４は、本発明の第３の実施形態であり、上記第２の実施形態とバルブピストン６４構成が異なっている。インジェクタ１０の全体構成および基本作動は上記第１の実施形態と同様であり、説明を省略する。図４のように、本実施形態では、バルブピストン６４の内部に軸方向に延びる連通路７を形成している。連通路７の上端は油密室６３に開口し、下端はバルブピストン６４の側壁を貫通する連通孔７１にて低圧室５５と連通している。   FIG. 4 shows a third embodiment of the present invention, which is different from the second embodiment in the configuration of the valve piston 64. The overall configuration and basic operation of the injector 10 are the same as those in the first embodiment, and a description thereof will be omitted. As shown in FIG. 4, in this embodiment, the communication passage 7 extending in the axial direction is formed inside the valve piston 64. The upper end of the communication path 7 opens into the oil tight chamber 63, and the lower end communicates with the low pressure chamber 55 through a communication hole 71 that penetrates the side wall of the valve piston 64.

連通路７の上端部はやや大径としてあって、ボール弁７３が収容されており、油密室６３のリークを補償するチェック弁を構成している。大径部の上端開口には連通孔７２を有するプレート部材が嵌合配設される。これにより、油密室６３の圧力が低下した時に、低圧室５５から連通孔７１、連通路７へ流入する燃料がボール弁７３を押し上げて油密室６３に補充することができる。   The upper end portion of the communication passage 7 has a slightly large diameter, and a ball valve 73 is accommodated to constitute a check valve that compensates for leakage in the oil tight chamber 63. A plate member having a communication hole 72 is fitted into the upper end opening of the large diameter portion. As a result, when the pressure in the oil tight chamber 63 decreases, the fuel flowing from the low pressure chamber 55 into the communication hole 71 and the communication passage 7 can push up the ball valve 73 to replenish the oil tight chamber 63.

本実施形態によっても、上記各実施形態と同様の効果が得られる。また、本実施形態では、バルブピストンプリセットスプリング５３を油密室６３内に配置している。このように、バルブピストンプリセットスプリング５３の他、各種部材の配設場所は特に限定されず、変更してもよい。   Also according to this embodiment, the same effects as those of the above embodiments can be obtained. In the present embodiment, the valve piston preset spring 53 is disposed in the oil tight chamber 63. Thus, the arrangement place of various members other than the valve piston preset spring 53 is not particularly limited and may be changed.

図５は、本発明の第４の実施形態であり、上記第２の実施形態とピエゾピストン６２構成が異なっている。インジェクタ１０の全体構成および基本作動は上記第１の実施形態と同様であり、説明を省略する。図５のように、本実施形態において、ピエゾピストン６２は、両端開口の筒状としてあり、その上端開口を閉鎖するようにピストン部材６６を配置して、これらピエゾピストン６２とピストン部材６６とシリンダ５およびバルブピストン６４とで囲まれる空間を油密室６３とする。このように、油密室６３を形成する一端閉鎖の筒状のピストンを、複数の部材で構成することもできる。また、本実施の形態では、シリンダ５の筒状部５１下端に設けたフランジ部５２を貫通する連通孔５６にて低圧部２６と低圧室５５を連通させている。   FIG. 5 shows a fourth embodiment of the present invention, which is different from the second embodiment in the configuration of the piezo piston 62. The overall configuration and basic operation of the injector 10 are the same as those in the first embodiment, and a description thereof will be omitted. As shown in FIG. 5, in this embodiment, the piezo piston 62 has a cylindrical shape with openings at both ends, and a piston member 66 is disposed so as to close the upper end opening, and the piezo piston 62, the piston member 66, and the cylinder are arranged. 5 and the valve piston 64 are defined as an oil-tight chamber 63. Thus, the cylindrical piston of the one end closure which forms the oil-tight chamber 63 can also be comprised with a some member. In the present embodiment, the low pressure portion 26 and the low pressure chamber 55 are communicated with each other through a communication hole 56 that penetrates the flange portion 52 provided at the lower end of the cylindrical portion 51 of the cylinder 5.

本実施形態によっても、上記各実施形態と同様の効果が得られる。さらに、本実施形態では、一端閉鎖の筒状ピストンを、閉鎖端部となるピストン部材６６と筒状部となるピエゾピストン６２の２つの部材に分割したので、一部材とする場合に比べて筒状部（特に閉鎖端側）の加工が容易になり、安価に製造できる。なお、ピストン部材６６とピエゾピストン６２の間にプレート部材を介設して、該プレート部材が油密室６３の上部壁を形成する構成としてもよい。   Also according to this embodiment, the same effects as those of the above embodiments can be obtained. Furthermore, in this embodiment, the cylindrical piston closed at one end is divided into two members, a piston member 66 serving as a closed end and a piezo piston 62 serving as a cylindrical portion. The shape part (especially the closed end side) can be easily processed and can be manufactured at low cost. A plate member may be interposed between the piston member 66 and the piezo piston 62 so that the plate member forms the upper wall of the oil-tight chamber 63.

以上のように、本発明は、アクチュエータの変位を油圧を介して伝達する機構において、２つのピストンを筒状シリンダの内外に配置することにより、摺動長が機構の全長に及ぼす影響を大幅に減少する。アクチュエータとしては、通電により変位を発生する素子であれば、いずれを用いてもよく、上記各実施形態で使用したピエゾ素子の他、磁歪素子等が挙げられる。これらピエゾ素子や磁歪素子のように、発生力は大きいが変位の小さいアクチュエータに本発明を適用することで、インジェクタ１０の制御弁駆動用の油圧伝達装置をコンパクトに形成できる。   As described above, according to the present invention, in the mechanism that transmits the displacement of the actuator via hydraulic pressure, the influence of the sliding length on the total length of the mechanism is greatly increased by arranging the two pistons inside and outside the cylindrical cylinder. Decrease. Any actuator may be used as long as it is an element that generates displacement when energized. Examples of the actuator include a magnetostrictive element and the like in addition to the piezoelectric element used in each of the above embodiments. By applying the present invention to an actuator that has a large generated force but a small displacement, such as a piezo element and a magnetostrictive element, a hydraulic transmission device for driving the control valve of the injector 10 can be made compact.

なお、上記各実施形態では、本発明を変位を拡大する油圧伝達装置に適用した例について説明したが、これに限られるものではない。例えば、発生力は小さいが変位の大きいアクチュエータに本発明を適用し、上記各実施形態と大径および小径ピストンの配置を逆にすることで、駆動力拡大装置とすることも可能である。   In each of the above embodiments, an example in which the present invention is applied to a hydraulic transmission device that expands displacement has been described. However, the present invention is not limited to this. For example, the present invention can be applied to an actuator having a small generated force but a large displacement, and the arrangement of the large-diameter and small-diameter pistons can be reversed from the above-described embodiments, whereby a driving force expanding device can be obtained.

本発明の第１の実施形態を示すインジェクタの全体構成を示す断面図である。It is sectional drawing which shows the whole structure of the injector which shows the 1st Embodiment of this invention. 第１の実施形態の主要部断面図である。It is principal part sectional drawing of 1st Embodiment. 本発明の第２の実施形態を示すインジェクタの主要部構成を示す断面図である。It is sectional drawing which shows the principal part structure of the injector which shows the 2nd Embodiment of this invention. 本発明の第３の実施形態を示すインジェクタの主要部構成を示す断面図である。It is sectional drawing which shows the principal part structure of the injector which shows the 3rd Embodiment of this invention. 本発明の第４の実施形態を示すインジェクタの主要部構成を示す断面図である。It is sectional drawing which shows the principal part structure of the injector which shows the 4th Embodiment of this invention. 従来のインジェクタの全体構成を示す断面図である。It is sectional drawing which shows the whole structure of the conventional injector.

符号の説明Explanation of symbols

１０ インジェクタ
１０１ ノズル部
１０２ 制御弁部
１０３ ピエゾ駆動部
１ バルブニードル
１１ 弁部
１２ 摺動部
１３ 細径部
１４ ハウジング
１５ 高圧通路
１６ 低圧通路
２１ バルブ室
２２ ３方弁第１シート
２３ ３方弁第２シート
２４ オリフィス
２６ 低圧部
３ ノズルニードル
３２ 油溜まり室
３４ 噴孔
４ 制御室
４１ サブオリフィス
５ シリンダ
５１ 筒状部
５２ フランジ
５３ バルブピストンプリセットスプリング
５４ 連通孔
５５ 低圧室
６１ ピエゾスタック（アクチュエータ）
６２ ピエゾピストン（第１ピストン）
６２１ 筒状部
６２２ フランジ部
６３ 油密室
６４ バルブピストン（第２ピストン）
６４１ 下端部
６４２ フランジ部
６５ ピエゾスプリング
６６ ピストン部材
７ 連通路
７１ 連通孔
７２ 連通孔
７３ ボール弁 DESCRIPTION OF SYMBOLS 10 Injector 101 Nozzle part 102 Control valve part 103 Piezo drive part 1 Valve needle 11 Valve part 12 Sliding part 13 Small diameter part 14 Housing 15 High pressure passage 16 Low pressure passage 21 Valve chamber 22 3 way valve 1st sheet 23 3 way valve 1st 2 seat 24 orifice 26 low pressure portion 3 nozzle needle 32 oil reservoir chamber 34 injection hole 4 control chamber 41 sub-orifice 5 cylinder 51 cylindrical portion 52 flange 53 valve piston preset spring 54 communication hole 55 low pressure chamber 61 piezo stack (actuator)
62 Piezo piston (first piston)
621 Tubular part 622 Flange part 63 Oil tight chamber 64 Valve piston (second piston)
641 Lower end part 642 Flange part 65 Piezo spring 66 Piston member 7 Communication path 71 Communication hole 72 Communication hole 73 Ball valve

Claims (6)

通電により変位を発生するアクチュエータと、上記アクチュエータと一体に変位する第１ピストンと、上記第１ピストンと油密室を挟んで対向する第２ピストンを有し、上記アクチュエータの変位を油圧を介して上記第２ピストンに伝達する油圧伝達装置において、上記第１および第２ピストンの一方を一端閉鎖の筒状として、その筒状部をハウジングに固定される筒状シリンダに外挿する一方、上記筒状シリンダに上記第１および上記第２ピストンのもう一方を内挿して、上記第１および第２ピストンを上記筒状シリンダの内外周面に対して摺動自在とし、かつ上記筒状部と上記筒状シリンダと上記第１および上記第２ピストンのもう一方とで囲まれる空間に作動油を充填して上記油密室としたことを特徴とする油圧伝達装置。   An actuator that generates a displacement by energization; a first piston that is displaced integrally with the actuator; and a second piston that faces the first piston with an oil-tight chamber interposed therebetween, and the displacement of the actuator is controlled by hydraulic pressure. In the hydraulic transmission device for transmitting to the second piston, one of the first and second pistons is formed in a cylindrical shape with one end closed, and the cylindrical portion is extrapolated to a cylindrical cylinder fixed to the housing, while the cylindrical shape is The other of the first and second pistons is inserted into a cylinder so that the first and second pistons can slide with respect to the inner and outer peripheral surfaces of the cylindrical cylinder, and the cylindrical portion and the cylinder A hydraulic transmission device characterized in that a hydraulic oil is filled in a space surrounded by a cylindrical cylinder and the other of the first and second pistons to form the oil tight chamber. 通電により変位を発生するアクチュエータと、上記アクチュエータと一体に変位する大径ピストンと、上記大径ピストンと油密室を挟んで対向する小径ピストンを有し、上記アクチュエータの変位を油圧を介して上記小径ピストンに拡大して伝達する油圧伝達装置において、上記大径ピストンを一端閉鎖の筒状として、その筒状部をハウジングに固定される筒状シリンダに外挿する一方、上記筒状シリンダに上記小径ピストンを内挿して、上記大径および小径ピストンを上記筒状シリンダの外周面および内周面に対してそれぞれ摺動自在とし、かつ上記大径ピストンの筒状部と上記筒状シリンダと上記小径ピストンとで囲まれる空間に作動油を充填して上記油密室としたことを特徴とする油圧伝達装置。   An actuator that generates displacement when energized, a large-diameter piston that is displaced integrally with the actuator, and a small-diameter piston that faces the large-diameter piston across an oil-tight chamber, and the displacement of the actuator is controlled by hydraulic pressure to the small-diameter piston. In the hydraulic transmission device that expands and transmits to the piston, the large-diameter piston has a cylindrical shape that is closed at one end, and the cylindrical portion is extrapolated to a cylindrical cylinder that is fixed to the housing, while the small-diameter is inserted into the cylindrical cylinder. A piston is inserted so that the large-diameter and small-diameter pistons can slide with respect to the outer peripheral surface and the inner peripheral surface of the cylindrical cylinder, respectively, and the cylindrical portion of the large-diameter piston, the cylindrical cylinder, and the small-diameter A hydraulic transmission device characterized in that the oil-tight chamber is formed by filling hydraulic oil in a space surrounded by a piston. 上記一端閉鎖の筒状としたピストンの、閉鎖端部と筒状部とを別部材にて構成した請求項１または２に記載の油圧伝達装置。   3. The hydraulic transmission device according to claim 1, wherein the closed end portion and the cylindrical portion of the one-end-closed piston are configured as separate members. 上記油密室と低圧部とを連通する連通路を設け、該連通路に、上記油密室の圧力が所定圧を下回った時に上記油密室に作動油を流入させるチェック弁を設けた請求項１から３のいずれか記載の油圧伝達装置。   The communication passage which connects the said oil-tight chamber and a low-pressure part is provided, The check valve which flows hydraulic oil into the said oil-tight chamber when the pressure of the said oil-tight chamber falls below predetermined pressure was provided in this communication passage from the said 1st 4. The hydraulic transmission device according to any one of 3. 上記アクチュエータがピエゾアクチュエータである請求項１から４のいずれか記載の油圧伝達装置。   5. The hydraulic transmission device according to claim 1, wherein the actuator is a piezo actuator. 請求項1から５のいずれか１つに記載の油圧伝達装置をノズルニードルの開閉を制御する制御弁の駆動部として内蔵し、上記ノズルニードルに閉弁方向の圧力を作用させる制御室を設けて、上記駆動部の上記小径ピストンによって上記制御弁を開閉駆動することにより、上記制御室の圧力を増減させて上記ノズルニードルを昇降させることを特徴とする燃料噴射装置。   A hydraulic pressure transmission device according to any one of claims 1 to 5 is incorporated as a control valve drive unit for controlling the opening and closing of the nozzle needle, and a control chamber is provided for applying pressure in the valve closing direction to the nozzle needle. The fuel injection device characterized in that the control valve is driven to open and close by the small-diameter piston of the drive unit, whereby the pressure in the control chamber is increased and decreased to raise and lower the nozzle needle.
JP2004143125A 2004-05-13 2004-05-13 Fuel injection device Expired - Fee Related JP4131251B2 (en)

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DE200510022137 DE102005022137A1 (en) 2004-05-13 2005-05-12 Hydraulic transmission device and fuel injection device

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DE102007050578B4 (en) 2007-10-20 2016-02-18 Hofer Forschungs- Und Entwicklungs Gmbh Transmission actuator and gearbox
JP2010019147A (en) 2008-07-09 2010-01-28 Nippon Soken Inc Fuel injection valve
DE102009000830A1 (en) * 2009-02-13 2010-08-19 Robert Bosch Gmbh Fuel injector with length-adjustable coupler concept
DE102010031497A1 (en) * 2010-07-19 2012-01-19 Robert Bosch Gmbh Fuel injector with hydraulic coupler unit

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Publication number Priority date Publication date Assignee Title
JP2009539025A (en) * 2006-05-31 2009-11-12 キャタピラー インコーポレイテッド Fuel injector control system

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