JP4670878B2 - Control valves and injectors - Google Patents

Control valves and injectors Download PDF

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JP4670878B2
JP4670878B2 JP2008057392A JP2008057392A JP4670878B2 JP 4670878 B2 JP4670878 B2 JP 4670878B2 JP 2008057392 A JP2008057392 A JP 2008057392A JP 2008057392 A JP2008057392 A JP 2008057392A JP 4670878 B2 JP4670878 B2 JP 4670878B2
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pressure
valve
chamber
valve body
seal portion
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JP2009215892A (en
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徹也 吉村
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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
    • 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
    • F02M2200/21—Fuel-injection apparatus with piezoelectric or magnetostrictive elements
    • 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
    • F02M2200/29—Fuel-injection apparatus having rotating means
    • 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
    • F02M2200/701—Linkage between actuator and actuated element, e.g. between piezoelectric actuator and needle valve or pump plunger mechanical

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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)

Description

本発明は、例えば内燃機関用インジェクタに適用されて、ノズルニードルを昇降させる３方弁構造の制御弁に関する。   The present invention relates to a control valve having a three-way valve structure that is applied to, for example, an injector for an internal combustion engine to raise and lower a nozzle needle.

例えばディーゼルエンジンにおいて、コモンレール式燃料噴射装置が知られている。各気筒に共通のコモンレールには、燃料供給ポンプから高圧燃料が圧送されて所定の燃料噴射圧となるように制御される。コモンレール用のインジェクタは、通常、ノズルニードルに閉弁方向の圧力を作用させる制御室と、制御室の圧力を制御する制御弁を有し、ピエゾアクチュエータで制御弁を駆動して制御室の圧力を増減する。   For example, in a diesel engine, a common rail fuel injection device is known. A common rail common to each cylinder is controlled so that high-pressure fuel is pumped from a fuel supply pump to a predetermined fuel injection pressure. Common rail injectors usually have a control chamber that applies pressure in the valve closing direction to the nozzle needle and a control valve that controls the pressure in the control chamber. The control valve is driven by a piezoelectric actuator to control the pressure in the control chamber. Increase or decrease.

例えば特許文献１に記載されているように、制御弁は、３方弁構造を有し、高圧通路に連通する高圧ポートと低圧通路に連通する低圧ポートを開閉して制御室の圧力を増減する。このような制御弁の一例を、図７に示す。図７（ａ）において、制御弁１００の弁体１０１は、高圧ポート１０２と低圧ポート１０３が開口する弁室１０４内に位置し、ピストン部材１０５によって駆動されて、高圧ポート１０２に続く高圧シート１０６および低圧ポート１０３に続く低圧シート１０７の一方に選択的に着座する。弁室１０４は、図示しない制御室と連通路にて常時連通しており、弁体１０１のシート位置を切り換えると、高圧ポートまたは低圧ポートと制御室が弁室１０４を介して連通する。弁体１０１形状は、例えば、高圧シート１０６側の下端面が平面状、低圧ポート１０３側の上端面が球面状に形成されている。
特開２００６−０４６３２３号公報 For example, as described in Patent Document 1, the control valve has a three-way valve structure, and opens and closes the high pressure port communicating with the high pressure passage and the low pressure port communicating with the low pressure passage to increase or decrease the pressure in the control chamber. . An example of such a control valve is shown in FIG. In FIG. 7A, the valve body 101 of the control valve 100 is located in the valve chamber 104 where the high-pressure port 102 and the low-pressure port 103 are opened, and is driven by the piston member 105 to continue to the high-pressure seat 106. And selectively seats on one of the low pressure seats 107 following the low pressure port 103. The valve chamber 104 is always in communication with a control chamber (not shown) through a communication path. When the seat position of the valve body 101 is switched, the high-pressure port or the low-pressure port and the control chamber communicate with each other via the valve chamber 104. The shape of the valve body 101 is formed, for example, such that the lower end surface on the high pressure sheet 106 side is flat and the upper end surface on the low pressure port 103 side is spherical.
JP 2006-046323 A

ところで、図示の制御弁構造において、高圧ポート１０２開放時の弁室１０４から制御室への燃料の流入は、制御弁１００の弁体１０１が低圧シート１０７に着座した状態でのリフト量と高圧シート径に依存する。ここでは、高圧シート径＝高圧ポート径であり、燃料流入量が、高圧シート周長さ×制御弁リフト量で表される流路面積Ｓにより決まる構造となっている。ただし実際には、弁体１０１相手部品を分割する必要があり、弁体１０１に加工精度の問題や、組み付け時の高圧ポートおよび低圧ポートの位置ずれ等により、図７（ｂ）のように、組み付け状態において弁体１０１に傾きが生じることがある。   By the way, in the illustrated control valve structure, the flow of fuel from the valve chamber 104 to the control chamber when the high pressure port 102 is opened is the lift amount and the high pressure seat when the valve body 101 of the control valve 100 is seated on the low pressure seat 107. Depends on the diameter. Here, the high pressure seat diameter is equal to the high pressure port diameter, and the fuel inflow amount is determined by the flow path area S expressed by the high pressure seat circumferential length × the control valve lift amount. However, in actuality, it is necessary to divide the valve body 101 mating parts. Due to problems in processing accuracy of the valve body 101, misalignment of the high pressure port and the low pressure port during assembly, etc., as shown in FIG. In the assembled state, the valve body 101 may be inclined.

さらに、弁室１０４に燃料が流入する際の流体力等により弁体１０１が回転すると、図７（ｃ）のように、面積Ｓは変動する。この場合、制御室への燃料流入量が変化することになるため、安定した噴射量を供給することが困難である。位置ずれの対策としては、弁体を複数部材で構成することにより相対移動可能としたものがあるが、構成が複雑となる。   Furthermore, when the valve body 101 rotates due to fluid force or the like when fuel flows into the valve chamber 104, the area S varies as shown in FIG. In this case, since the amount of fuel flowing into the control room changes, it is difficult to supply a stable injection amount. As a countermeasure against the positional deviation, there is a valve body that is configured to be relatively movable by being composed of a plurality of members, but the configuration is complicated.

そこで、本発明は、ディーゼルエンジンのコモンレール式燃料噴射装置のインジェクタ等に使用され、軸方向の両端にシート部を構成した３方弁構造の制御弁において、両シートの軸ずれおよび弁体の回転による、流路面積の変動を回避可能な構造とし、燃料噴射量の変動を防ぐことを目的とする。   Accordingly, the present invention is a control valve having a three-way valve structure that is used in an injector or the like of a common rail fuel injection device of a diesel engine and has seat portions at both ends in the axial direction. Therefore, it is intended to prevent the fluctuation of the fuel injection amount by making the structure capable of avoiding the fluctuation of the flow path area.

請求項１の発明は、アクチュエータで駆動されるピストン部材が、弁室内に配置された弁体を軸方向に駆動して、上記弁室の対向面に設けた高圧シール部および低圧シール部の一方に選択的に着座させることにより、上記高圧シール部に連通する高圧ポートおよび上記低圧シール部に連通する低圧ポートを開閉して、上記弁室と常時連通する制御室の制御圧力を増減する制御弁であって、
上記弁体は、駆動方向の一方の端面側に、上記高圧シール部に着座する高圧シート部を設け、他方の端面側に、上記低圧シール部に着座する低圧シート部を設けるとともに、上記高圧シート部には、上記高圧ポートの対向位置を凹陥させた座ぐり部を形成して、該座ぐり部の外周縁部が着座時の高圧シート位置となり、かつ、高圧シート径＞高圧ポート径となる形状としたことを特徴とする。 The invention of claim 1, the piston member driven by the actuator drives the valve body disposed in the valve chamber in the axial direction, one of the high-pressure seal portion and the low-pressure seal portion provided on the opposite face of the valve chamber A control valve that opens and closes the high-pressure port communicating with the high-pressure seal portion and the low-pressure port communicated with the low-pressure seal portion by selectively seating on the control chamber, thereby increasing or decreasing the control pressure of the control chamber always communicating with the valve chamber Because
The valve body is provided with a high-pressure seat portion seated on the high-pressure seal portion on one end surface side in the driving direction, and a low-pressure seat portion seated on the low-pressure seal portion on the other end surface side, and the high-pressure seat A counterbore part in which the facing position of the high-pressure port is recessed is formed in the part, and the outer peripheral edge of the counterbore part becomes a high-pressure seat position when seated, and the high-pressure seat diameter> the high-pressure port diameter. It is characterized by its shape.

上記構成によれば、高圧ポート径より大きい座ぐり部を形成することで、座ぐり径が高圧シート径となり、シートの位置ずれをキャンセルして、弁体の傾きや回転により流路面積が変化するのを抑制することができる。よって、流量変動による制御圧の変化を抑制し、例えばインジェクタの背圧制御に適用されて、安定した燃料噴射を可能とする。   According to the above configuration, by forming the counterbore portion larger than the high-pressure port diameter, the counterbore diameter becomes the high-pressure seat diameter, canceling the positional deviation of the seat, and changing the flow path area due to the inclination and rotation of the valve body Can be suppressed. Therefore, the change in the control pressure due to the flow rate fluctuation is suppressed and applied to, for example, the back pressure control of the injector, thereby enabling stable fuel injection.

請求項２の発明では、上記弁体は、上記座ぐり部外周縁部の周長さをＬ１、上記座ぐり部の深さをＤ１、上記高圧ポート開口縁部の周長さをＬ２、上記高圧ポート開放時の上記弁体のリフト量をＨ１とした時に、下記式（１）〜（３）が成立する構成とした。
式（１）：Ｓ１＝Ｌ１×Ｈ１
式（２）：Ｓ２＝Ｌ２×（Ｈ１＋Ｄ１）
式（３）：Ｓ１＜Ｓ２ According to a second aspect of the present invention, the valve body has a circumferential length of the outer peripheral edge portion of the counterbore portion as L1, a depth of the counterbore portion as D1, and a circumferential length of the high pressure port opening edge portion as L2. When the lift amount of the valve body when the high-pressure port is opened is H1, the following formulas (1) to (3) are established.
Formula (1): S1 = L1 × H1
Formula (2): S2 = L2 × (H1 + D1)
Formula (3): S1 <S2

この時、流路面積Ｓ１が高圧シール部開弁時の絞り部となり、高圧シール部と低圧シール部の位置ずれ、弁体の傾きによる回転が生じても、流路面積が変化しないので、燃料流入量の変動を抑制する効果が高い。 At this time, the flow passage area S1 becomes a throttle portion when the high-pressure seal portion is opened, and the flow passage area does not change even if the high-pressure seal portion and the low-pressure seal portion are misaligned or rotated due to the inclination of the valve body. Highly effective in suppressing fluctuations in inflow.

請求項３の発明では、上記高圧シート位置を除く、上記制御室への流入通路の最小断面積をＳ３とした時に、下記式（４）が成立する構成とした。
式（４）：Ｓ１／Ｓ３＜２ In the invention of claim 3, when the minimum cross-sectional area of the inflow passage to the control chamber excluding the high-pressure seat position is S3, the following expression (4) is established.
Formula (4): S1 / S3 <2

この範囲では、高圧シート部における流路面積Ｓ１と、その他通路の最小断面積Ｓ３との面積比に対する流量変化が大きいので、本発明を適用することによる効果が高い。   In this range, since the flow rate change with respect to the area ratio between the flow path area S1 in the high-pressure sheet portion and the minimum cross-sectional area S3 of the other passage is large, the effect of applying the present invention is high.

請求項４の発明では、上記弁体は、上記一方の端面側の低圧シート部が球面または円錐状に形成されて、円錐状に形成された上記低圧シール部に対向する一方、上記他方の端面側の高圧シート部が平面状に形成されて、平面状に形成された上記高圧シール部に対向している。 According to a fourth aspect of the present invention, the valve element has a low-pressure seat portion on one end face side formed in a spherical shape or a conical shape, and faces the low-pressure seal portion formed in a conical shape, while the other end face is provided. The high-pressure sheet portion on the side is formed in a flat shape and faces the high-pressure seal portion formed in a flat shape.

このように、シート部の一方を平面シートとすると、位置ずれに対応しやすく、加工も容易となる。また、異物の噛みこみによるシート不良にも対応しやすい。   As described above, when one of the sheet portions is a flat sheet, it is easy to cope with the positional deviation and the processing becomes easy. In addition, it is easy to deal with sheet defects caused by foreign matter biting.

請求項５の発明では、上記弁体は、上記座ぐり部の内周面が上記一方の端面に向けて拡径するテーパ面形状を有し、該テーパ面の傾斜角度が３０°以上９０°未満である。   In the invention according to claim 5, the valve body has a tapered surface shape in which an inner peripheral surface of the counterbore portion expands toward the one end surface, and an inclination angle of the tapered surface is 30 ° or more and 90 °. Is less than.

テーパ面とすることで加工が容易になり、シート位置も設定しやすい。ただし、傾斜角度が小さいと、研削による径変化が大きいので３０°以上とするのがよい。   By using a tapered surface, processing becomes easy and the sheet position is easy to set. However, if the inclination angle is small, the diameter change due to grinding is large, so it is preferable to set it to 30 ° or more.

請求項６の発明では、アクチュエータをピエゾ式アクチュエータとする。応答性のよいピエゾアクチュエータを用い、本発明を適用することで、制御性をより向上させることができる。   In the invention of claim 6, the actuator is a piezoelectric actuator. By using a piezoelectric actuator with good response and applying the present invention, controllability can be further improved.

請求項７の発明は、請求項１ないし６のいずれか記載の制御弁を用いたインジェクタであって、上記制御室の圧力を、噴孔を開閉するノズルニードルの閉弁方向に作用させ、上記アクチュエータが上記ピストン部材を介して上記弁体を開閉することにより燃料噴射を行う。   A seventh aspect of the present invention is an injector using the control valve according to any one of the first to sixth aspects, wherein the pressure in the control chamber is caused to act in a valve closing direction of a nozzle needle that opens and closes the nozzle hole. The actuator performs fuel injection by opening and closing the valve body via the piston member.

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は本発明の制御弁Ｖ構成を、図２はこの制御弁Ｖを組み込んだインジェクタＩの概略構成を示す図で、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する。図２において、エンジンの各気筒に対応して設けられるインジェクタＩは、各気筒に共通のコモンレール（図示せず）に接続され、コモンレールには高圧サプライポンプ（図示せず）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ている。   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 a control valve V according to the present invention, and FIG. 2 is a diagram showing a schematic configuration of an injector I incorporating the control valve V, which will be described as an application example to a common rail fuel injection device of a diesel engine. In FIG. 2, an injector I provided corresponding to each cylinder of the engine is connected to a common rail (not shown) common to each cylinder, and fuel fed by a high pressure supply pump (not shown) is fed to the common rail. It is stored at a predetermined high pressure corresponding to the injection pressure.

図２（ａ）において、インジェクタＩは、ハウジングＨ内の中間部に制御弁Ｖを、上半部に、ピエゾ式アクチュエータを構成するピエゾスタック１と駆動力伝達機構６を収容している。ハウジングＨの下半部には、ノズルニードル５が収容され、図示の状態では、先端が噴孔５４を閉鎖している。ハウジングＨ内には、また、軸方向に延びる高圧通路１２と低圧通路１３が設けられ、ハウジングＨ側壁に開口する高圧通路１２の通路入口１１はコモンレールに、ハウジングＨ上壁に開口する低圧通路１３の通路出口１４は図示しない燃料タンクへ連通している。   In FIG. 2A, the injector I accommodates a control valve V in an intermediate part in a housing H and a piezo stack 1 and a driving force transmission mechanism 6 constituting a piezo actuator in an upper half part. The nozzle needle 5 is accommodated in the lower half of the housing H, and the tip closes the nozzle hole 54 in the state shown in the drawing. In the housing H, a high-pressure passage 12 and a low-pressure passage 13 that extend in the axial direction are provided, and the passage inlet 11 of the high-pressure passage 12 that opens to the side wall of the housing H is a common rail, and the low-pressure passage 13 that opens to the upper wall of the housing H. The passage outlet 14 communicates with a fuel tank (not shown).

ハウジングＨ内において、ノズルニードル５周りの空間は、油溜まり室５２を構成している。油溜まり室５２には、その上部壁に開口する高圧通路１２を介してコモンレールから高圧燃料が供給されている。ノズルニードル５の上端部は、油溜まり室５２の上部壁に固定された筒状部４２内に摺動自在に保持され、ノズルニードル５の中間部外周に設けたフランジ５１と筒状部４２下端部との間に配設したスプリング５６がノズルニードル５を閉弁方向に付勢している。   In the housing H, the space around the nozzle needle 5 constitutes an oil reservoir chamber 52. The oil reservoir chamber 52 is supplied with high-pressure fuel from the common rail through the high-pressure passage 12 that opens to the upper wall. An upper end portion of the nozzle needle 5 is slidably held in a cylindrical portion 42 fixed to the upper wall of the oil sump chamber 52, and a flange 51 provided on the outer periphery of the intermediate portion of the nozzle needle 5 and a lower end of the cylindrical portion 42. A spring 56 disposed between the two portions biases the nozzle needle 5 in the valve closing direction.

油溜まり室５２には、その上部壁に開口する高圧通路１２を介してコモンレールから高圧燃料が供給されている。ハウジングＨの下端面中央には、サック部５３形成壁を貫通して噴孔５４が形成されており、ノズルニードル５は図示の下端位置において、円錐形状の先端部がノズルシート５５に着座してサック部５３を閉じ、油溜まり室５２から噴孔５４への燃料供給を遮断する。   The oil reservoir chamber 52 is supplied with high-pressure fuel from the common rail through the high-pressure passage 12 that opens to the upper wall. A nozzle hole 54 is formed in the center of the lower end surface of the housing H so as to penetrate the sack portion 53 forming wall. The nozzle needle 5 is seated on the nozzle sheet 55 at the lower end position shown in the figure. The sack portion 53 is closed, and the fuel supply from the oil reservoir chamber 52 to the nozzle hole 54 is shut off.

ノズルニードル５の上端面は、制御室であるノズル背圧室４に面している。ノズル背圧室４は、連通路４１を介して制御弁Ｖの弁室２と常時連通し、油溜まり室５２から弁室２を経由して導入される燃料の圧力が開弁方向に作用している。一方、油溜まり室５２の高圧燃料がノズルニードル５先端部の円錐面に上向きに作用しノズルニードル５を開弁方向に付勢している。３方弁構造の制御弁Ｖを用いてノズル背圧室４の圧力を増減させると、ノズルニードル５が昇降する。   The upper end surface of the nozzle needle 5 faces the nozzle back pressure chamber 4 which is a control chamber. The nozzle back pressure chamber 4 is always in communication with the valve chamber 2 of the control valve V through the communication passage 41, and the pressure of the fuel introduced from the oil reservoir chamber 52 through the valve chamber 2 acts in the valve opening direction. ing. On the other hand, the high-pressure fuel in the oil reservoir chamber 52 acts upward on the conical surface of the tip of the nozzle needle 5 to urge the nozzle needle 5 in the valve opening direction. When the pressure in the nozzle back pressure chamber 4 is increased or decreased using the control valve V having a three-way valve structure, the nozzle needle 5 moves up and down.

３方弁構造の制御弁Ｖは、弁室２内に収容した弁体３を、弁室２の底面に設けた高圧シール部２１と、天井面に設けた低圧シール部２２のいずれか一方に選択的に着座させることにより、ノズル背圧室４の圧力を制御する。弁室２の平坦な底面には、高圧ポート２３が開口し、その開口部周りの環状平面部を高圧シール部２１としている。同様に、弁室２の天井面に開口する低圧ポート２４周りの環状テーパ面にて低圧シール部２２が形成され、高圧ポート２３と低圧ポート２４は、弁体３の駆動方向に対向位置している。高圧ポート２３は、連通路２５を介して油溜まり室５２に連通し、高圧通路１２から燃料が供給されている。一方、低圧ポート２４は絞り通路１５にて低圧通路１３に連通している。弁体３は、外周に設けたフランジ３３と弁室２底面の間に配設したスプリング２６にて上方に付勢され、初期位置において低圧シール部２２に着座する図示の位置にある。制御弁Ｖの詳細、特に弁体３形状については後述する。 The control valve V having a three-way valve structure is configured such that the valve body 3 accommodated in the valve chamber 2 is attached to either the high pressure seal portion 21 provided on the bottom surface of the valve chamber 2 or the low pressure seal portion 22 provided on the ceiling surface. By selectively seating, the pressure of the nozzle back pressure chamber 4 is controlled. A high pressure port 23 opens on the flat bottom surface of the valve chamber 2, and an annular flat portion around the opening serves as a high pressure seal portion 21. Similarly, a low pressure seal portion 22 is formed by an annular tapered surface around the low pressure port 24 that opens to the ceiling surface of the valve chamber 2, and the high pressure port 23 and the low pressure port 24 are positioned opposite to each other in the driving direction of the valve body 3. Yes. The high pressure port 23 communicates with the oil sump chamber 52 via the communication path 25, and fuel is supplied from the high pressure path 12. On the other hand, the low pressure port 24 communicates with the low pressure passage 13 through the throttle passage 15. The valve body 3 is biased upward by a spring 26 disposed between the flange 33 provided on the outer periphery and the bottom surface of the valve chamber 2 and is in the illustrated position where it is seated on the low pressure seal portion 22 in the initial position. Details of the control valve V, in particular, the shape of the valve body 3 will be described later.

駆動力伝達機構６は、応答性の良好なピエゾ式アクチュエータの駆動力を、大小２つのピストン部材を用いて制御弁Ｖの弁体３に伝達する。ピエゾスタック１はＰＺＴ等の圧電セラミック層と電極層を交互に積層したもので、図示しない駆動回路により充放電されて、積層方向（図の上下方向）に伸縮する。駆動力伝達機構６は、筒状のシリンダ部材６１内に、大径のピエゾピストン６２と小径のバルブピストン６４を摺動自在に設け、両ピストン部材の間に作動油を充填した油密室６３を設けている。ピエゾピストン６２は、シリンダ部材６１の上方に突出する大径の円盤部がピエゾスタック１の下端面に当接し、この円盤部とシリンダ部材６１下端外周縁部との間に配設したピエゾスプリング６５によってピエゾスタック１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１の伸縮に伴い一体に上下動する。   The driving force transmission mechanism 6 transmits the driving force of a piezo-type actuator with good responsiveness to the valve body 3 of the control valve V using two large and small piston members. The piezo stack 1 is formed by alternately stacking piezoelectric ceramic layers such as PZT and electrode layers. The piezo stack 1 is charged and discharged by a drive circuit (not shown) and expands and contracts in the stacking direction (vertical direction in the figure). The driving force transmission mechanism 6 includes a cylindrical cylinder member 61 in which a large-diameter piezo piston 62 and a small-diameter valve piston 64 are slidably provided, and an oil-tight chamber 63 filled with hydraulic oil is provided between both piston members. Provided. The piezo piston 62 has a large-diameter disk portion projecting upward from the cylinder member 61 abuts on the lower end surface of the piezo stack 1, and a piezo spring 65 disposed between the disk portion and the lower peripheral edge of the cylinder member 61. Thus, a certain initial load is applied to the piezo stack 1. As a result, the piezo piston 62 moves up and down as the piezo stack 1 expands and contracts.

バルブピストン６４の下端面は、その下方のピン部材７に当接している。ピン部材７は、高圧ポート２３内に摺動自在に保持され、下端が弁室２１内の弁体３に当接している。バルブピストン６４は下端大径部とシリンダ部材６１の間に配設したバルブスプリング６６によって下方に付勢されており、これにより、ピン部材７と一体に上下動可能である。ピエゾスタック１が伸長してピエゾピストン６２を押圧すると、油密室６３の圧力が上昇しバルブピストン６４を駆動する。この時、ピエゾピストン６２とバルブピストン６４の径差に応じて移動量が増加するので、変位を拡大して伝達することができる。   The lower end surface of the valve piston 64 is in contact with the pin member 7 below. The pin member 7 is slidably held in the high-pressure port 23, and the lower end is in contact with the valve body 3 in the valve chamber 21. The valve piston 64 is urged downward by a valve spring 66 disposed between the large diameter portion at the lower end and the cylinder member 61, and can move up and down integrally with the pin member 7. When the piezo stack 1 extends and presses the piezo piston 62, the pressure in the oil tight chamber 63 rises and the valve piston 64 is driven. At this time, the amount of movement increases in accordance with the diameter difference between the piezo piston 62 and the valve piston 64, so that the displacement can be enlarged and transmitted.

ここで、図１により本発明の制御弁Ｖについて説明する。図１（ａ）に示すように、弁体３は、フランジ３３より下方が略円柱状、上方が略半球状の形状を有するブロック状で、略円柱状の下半部底面に高圧シート部３１を形成し、略半球状の上半部頂面に低圧シート部３２を形成している。弁体３は、一方の端部（図の下端部）において、高圧ポート２３に対向する下端面中央部に、座ぐり部３４となる凹陥部を形成し、その外周に形成される環状平面部を高圧シート部３１として、該高圧シート部３１が、対向する高圧シール部２１に着座して高圧ポート２３を閉鎖するようになっている。弁体３の他方の端部（図の上端部）は、ピン部材７に当接する平坦な頂部外周に、球面状の低圧シート部３２を形成し、該低圧シート部３２が、対向する低圧シール部２２に着座して低圧ポート２４を閉鎖する。 Here, the control valve V of the present invention will be described with reference to FIG. As shown in FIG. 1A, the valve body 3 is a block shape having a substantially cylindrical shape below the flange 33 and a substantially hemispherical shape above the flange 33, and the high pressure seat portion 31 on the bottom surface of the substantially cylindrical lower half portion. The low-pressure sheet portion 32 is formed on the top surface of the upper half portion of a substantially hemispherical shape. The valve body 3 is formed at one end (lower end in the figure) with a recessed portion serving as a counterbore 34 at the center of the lower end surface facing the high pressure port 23, and an annular flat portion formed on the outer periphery thereof. The high-pressure seat portion 31 is seated on the opposing high-pressure seal portion 21 and closes the high-pressure port 23. The other end portion (upper end portion in the figure) of the valve body 3 forms a spherical low-pressure seat portion 32 on the flat top outer periphery that contacts the pin member 7, and the low-pressure seat portion 32 is opposed to the low-pressure seal. Sitting on the part 22 closes the low pressure port 24.

シート形状は、高圧側では、弁体３側の高圧シート部３１が平面、対向する高圧シール部２１が平面であり、低圧側では、弁体３側の低圧シート部３１が球面または円錐面、対向する低圧シール部２２が円錐面であることが望ましい。このように、１つの弁体３で２つの通路をシートする場合には、高圧側または低圧側の一方を平面シートとするとよく、上下シートの軸ずれに対応しやすくなる。本発明では、高圧側を平面シートとして、さらに座ぐり部３４を設定することで、上下シートの軸ずれによる流量変動を抑制することができる。 The sheet shape is such that, on the high pressure side, the high pressure seat portion 31 on the valve body 3 side is flat, the opposing high pressure seal portion 21 is flat, and on the low pressure side, the low pressure seat portion 31 on the valve body 3 side is spherical or conical, It is desirable that the opposing low pressure seal portions 22 be conical surfaces. Thus, when seating two passages with one valve body 3, one of the high-pressure side or the low-pressure side may be a flat sheet, and it becomes easy to cope with the axial deviation of the upper and lower seats. In the present invention, the flow rate fluctuation due to the axial deviation of the upper and lower sheets can be suppressed by setting the counterbore part 34 with the high pressure side as a flat sheet.

図１（ｂ）は、制御弁Ｖの高圧ポート２３近傍を拡大して示す断面図である。本実施形態において、弁体３の座ぐり部３４は、平坦面に座ぐり加工を施すことにより形成された、略台形断面形状の凹陥部で、内周側面は下方へ向けて拡径するテーパ面となっている。開口縁部（図の下端部）の径、すなわち座ぐり径は、高圧ポート２３より大径となっている。この時、高圧シート部３１の内周縁部となる、座ぐり部３４の開口縁部（図の下端部）は、弁体３が対向する高圧シール部２１に着座した時の、高圧シート位置となる。このように本発明では、座ぐり径＝高圧シート径＞高圧ポート径となるように、弁体３の座ぐり部３４形状を設定しており、これにより、シート部流量を安定にすることができる。 FIG. 1B is an enlarged cross-sectional view showing the vicinity of the high-pressure port 23 of the control valve V. In this embodiment, the counterbore part 34 of the valve body 3 is a recessed part having a substantially trapezoidal cross-sectional shape formed by carrying out counterbore processing on a flat surface, and the inner peripheral side surface is a taper whose diameter is expanded downward. It is a surface. The diameter of the opening edge (the lower end in the figure), that is, the counterbore diameter is larger than that of the high-pressure port 23. At this time, the opening edge portion (lower end portion in the figure) of the counterbore portion 34 which is the inner peripheral edge portion of the high pressure seat portion 31 is positioned at the position of the high pressure seat when the valve body 3 is seated on the opposing high pressure seal portion 21. Become. Thus, in the present invention, the shape of the counterbore part 34 of the valve body 3 is set so that the counterbore diameter = the high-pressure seat diameter> the high-pressure port diameter, thereby stabilizing the seat part flow rate. it can.

好適には、座ぐり部３４開口縁部の周長さをＬ１、座ぐり部３４の深さをＤ１、高圧ポート２３開口縁部の周長さをＬ２、高圧ポート２３開放時の弁体３のリフト量をＨ１とした時に、下記式（１）〜（３）が成立する構成とする。
式（１）：Ｓ１＝Ｌ１×Ｈ１
式（２）：Ｓ２＝Ｌ２×（Ｈ１＋Ｄ１）
式（３）：Ｓ１＜Ｓ２ Preferably, the peripheral length of the opening edge of the counterbore part 34 is L1, the depth of the counterbore part 34 is D1, the peripheral length of the opening edge of the high pressure port 23 is L2, and the valve body 3 when the high pressure port 23 is opened. The following formulas (1) to (3) are established when the lift amount of H is H1.
Formula (1): S1 = L1 × H1
Formula (2): S2 = L2 × (H1 + D1)
Formula (3): S1 <S2

式（１）で表されるＳ１は、弁体３がリフトした時の高圧シート部３１から弁室２へ至る流路の開口面積を示し、式（２）で表されるＳ２は、弁体３がリフトした時の高圧ポート２３出口部における流路の開口面積を示している。式（３）は、高圧シート部３１における流路面積Ｓ１が、高圧ポート２３における流路面積Ｓ２より小さく、高圧ポート２３から弁室２への燃料流入量が、絞り部となる弁体３の高圧シート位置における流路面積Ｓ１に依存することを示す。式（３）のようにすると、流路面積Ｓ１は、弁体２の傾きやシート位置のずれによらず、ほぼ一定となるので、流量の変動を抑制することができる。   S1 represented by the formula (1) indicates an opening area of the flow path from the high-pressure seat portion 31 to the valve chamber 2 when the valve body 3 is lifted, and S2 represented by the formula (2) represents the valve body. 3 shows the opening area of the flow path at the outlet of the high-pressure port 23 when 3 is lifted. Equation (3) indicates that the flow passage area S1 in the high pressure seat portion 31 is smaller than the flow passage area S2 in the high pressure port 23, and the amount of fuel flowing from the high pressure port 23 into the valve chamber 2 is It shows that it depends on the flow path area S1 at the high-pressure sheet position. If Expression (3) is used, the flow path area S1 is substantially constant regardless of the inclination of the valve body 2 and the displacement of the seat position, so that fluctuations in the flow rate can be suppressed.

図１（ａ）に示すように、弁体３の座ぐり角度、すなわち、弁体３下端面と座ぐり部３４の内周側面とのなす角度は、９０°未満とすることで内周側面がテーパ面となり、座ぐり加工が容易になって、高圧シート位置が設定しやすくなる。弁体３下端面の座ぐり径は、ノズル背圧室４への燃料流入量を決定するための重要な寸法で、精度よく加工する必要があり、また、弁体３は高圧燃料をシールする構造であるから、高硬度、高精度（平面度、面粗度等）である必要がある。これを実現するため、通常は、テーパ形状切削後、熱処理、研削により座ぐり径を設定することになる。ただし、テーパ角度が小さくなるほど、研削による径変化が大きく、またエッジ（座ぐり径部）のだれにより径測定（エッジが不明瞭）が困難となるおそれがある。そこで、量産を考慮した、実現可能な角度として、通常は、座ぐり角度を３０°以上９０°未満とすることが好ましい。   As shown in FIG. 1 (a), the counterbore angle of the valve body 3, that is, the angle formed between the lower end surface of the valve body 3 and the inner peripheral side surface of the counterbore part 34 is set to be less than 90 °. Becomes a tapered surface, countersunk processing is facilitated, and the position of the high-pressure seat is easily set. The counterbore diameter of the lower end surface of the valve body 3 is an important dimension for determining the amount of fuel flowing into the nozzle back pressure chamber 4 and needs to be processed with high precision. The valve body 3 seals high-pressure fuel. Since it is a structure, it needs to have high hardness and high accuracy (flatness, surface roughness, etc.). In order to realize this, the counterbore diameter is usually set by heat treatment and grinding after the taper-shaped cutting. However, as the taper angle becomes smaller, the diameter change due to grinding becomes larger, and there is a possibility that it becomes difficult to measure the diameter (edge is unclear) due to the edge (spot face diameter portion). Therefore, it is usually preferable that the counterbore angle is 30 ° or more and less than 90 ° as a realizable angle considering mass production.

上記構成のインジェクタＩの作動と、弁体３形状による効果について説明する。図２（ａ）は無噴射時の状態で、ピエゾスタック１は放電状態で縮小している。弁体３は、上端位置にあって低圧シール部２２に続く低圧ポート２４を閉鎖し、これにより、低圧通路１３と弁室２との連通が遮断される。この時、低圧シール部２２に対向する高圧シール部２１が開放され、弁室２は、高圧通路１２から高圧ポート２３、高圧シール部２１を介して流入する燃料により高圧となっている。連通路４１を介して弁室２と常時連通するノズル背圧室４も高圧となる。ノズルニードル５は、ノズル背圧室４の圧力とスプリング５６の付勢力によってノズルシート５５に着座し、噴孔５４は閉鎖されている。 The operation of the injector I having the above configuration and the effect of the shape of the valve body 3 will be described. FIG. 2A shows a state without injection, and the piezo stack 1 is reduced in a discharged state. The valve body 3 closes the low-pressure port 24 that is in the upper end position and continues to the low-pressure seal portion 22, thereby blocking communication between the low-pressure passage 13 and the valve chamber 2. At this time, the high-pressure seal portion 21 facing the low-pressure seal portion 22 is opened, and the valve chamber 2 is at a high pressure by the fuel flowing from the high-pressure passage 12 through the high-pressure port 23 and the high-pressure seal portion 21. The nozzle back pressure chamber 4 that is always in communication with the valve chamber 2 via the communication passage 41 is also at a high pressure. The nozzle needle 5 is seated on the nozzle seat 55 by the pressure of the nozzle back pressure chamber 4 and the biasing force of the spring 56, and the injection hole 54 is closed.

図２（ｂ）は噴射時の状態で、図示しない駆動回路からピエゾスタック１に通電すると、ピエゾスタック１が充電されて伸長する。ピエゾスタック１とともにピエゾピストン６２が下方に移動し、油密室６３の作動油（ここでは軽油）が圧縮されると、この作動油の圧力でバルブピストン６４が下方に移動する。そして、ピン部材７が弁体３を押し下げて低圧シール部２２から離座させ、さらに下方変位して高圧シール部２１に着座させる。この時、ノズル背圧室４が弁室２、低圧シール部２２、低圧ポート２４を介して低圧通路１３に連通し、ノズル背圧室４の圧力が降下する。ノズルニードル５に作用する下向きの付勢力が上向きの付勢力を下回ると、ノズルシート５５から離座し、噴孔５４が開放されて燃料噴射が開始される。ここで、低圧シール部２２下流に絞り部１５を有する流路構成とすると、ノズル背圧室４の圧力降下は緩やかとなり、ノズル開弁速度を小さくすることができる。 FIG. 2B shows a state at the time of injection, and when the piezo stack 1 is energized from a drive circuit (not shown), the piezo stack 1 is charged and extended. When the piezo piston 62 moves downward together with the piezo stack 1 and the hydraulic oil (light oil here) in the oil tight chamber 63 is compressed, the valve piston 64 moves downward by the pressure of the hydraulic oil. Then, the pin member 7 pushes down the valve body 3 to be separated from the low pressure seal portion 22, and further displaced downward to be seated on the high pressure seal portion 21. At this time, the nozzle back pressure chamber 4 communicates with the low pressure passage 13 via the valve chamber 2 , the low pressure seal portion 22, and the low pressure port 24, and the pressure in the nozzle back pressure chamber 4 drops. When the downward urging force acting on the nozzle needle 5 is less than the upward urging force, the nozzle needle 5 is separated from the nozzle seat 55, the nozzle hole 54 is opened, and fuel injection is started. Here, if the flow path configuration has the throttle portion 15 downstream of the low pressure seal portion 22, the pressure drop in the nozzle back pressure chamber 4 becomes gentle, and the nozzle valve opening speed can be reduced.

ピエゾスタック１への通電が終了し、ピエゾスタック１を放電して収縮させると、ピエゾピストン６２が上方へ移動し、油密室６３の圧力が降下する。これによりバルブピストン６４およびピン部材７による弁体３の押し下げ力が解除され、弁体３が高圧シール部２１から離座し、さらに上方変位して低圧シール部２２に着座する。弁室２に高圧通路１２から高圧ポート２３、高圧シール部２１を介して燃料が流入し、さらに連通路４１から流入する燃料でノズル背圧室４が所定の高圧となると、ノズルニードル５が下降して閉弁し、噴射を終了する。 When energization to the piezo stack 1 is completed and the piezo stack 1 is discharged and contracted, the piezo piston 62 moves upward and the pressure in the oil tight chamber 63 drops. As a result, the pressing force of the valve body 3 by the valve piston 64 and the pin member 7 is released, the valve body 3 is separated from the high-pressure seal portion 21, is further displaced upward, and is seated on the low-pressure seal portion 22. When the fuel flows into the valve chamber 2 from the high pressure passage 12 through the high pressure port 23 and the high pressure seal portion 21 and the nozzle back pressure chamber 4 reaches a predetermined high pressure with the fuel flowing in from the communication passage 41, the nozzle needle 5 is lowered. Then, the valve is closed to finish the injection.

この時、ノズルニードル５の閉弁速度は、ノズル背圧室４への燃料流入量により決まることになる。本実施形態において使用しているピエゾスタック１は、非常に微小変位であることから、制御弁Ｖにて設定できる弁体３のリフト量も小さくなる。このため、高圧通路１２から弁室２を経てノズル背圧室４へ至る燃料流入通路は、通常、高圧ポート２３の出口部付近で最も絞る構造、またはノズル背圧室４へ至る通路の最小断面積、例えば連通路４１との２重絞りとなる可能性が高い。一方、本構造を具現化すると、弁体３を弁室２に収容するために相手部品である高圧シール部２１、低圧シール部２２を分割する必要があり、通常はノックピンで両部品の位置決めをするが、ノック穴位置および内径、ノックピン外径等に公差を持たせる必要がある。このため図３（ａ）に示すように、実際の組み付け状態では、各公差範囲内で高圧シール部２１、低圧シール部２２の軸心が一致しない軸ずれが発生する。また、弁体３をピン部材７で押す構造においては、両当接面の加工精度に限界があり、例えば数μｍの傾斜が発生して、弁体３が傾きが生じるおそれがある。 At this time, the valve closing speed of the nozzle needle 5 is determined by the amount of fuel flowing into the nozzle back pressure chamber 4. Since the piezo stack 1 used in this embodiment has a very small displacement, the lift amount of the valve body 3 that can be set by the control valve V is also small. For this reason, the fuel inflow passage from the high pressure passage 12 through the valve chamber 2 to the nozzle back pressure chamber 4 is usually the most restrictive structure near the outlet of the high pressure port 23, or the minimum disconnection of the passage to the nozzle back pressure chamber 4 There is a high possibility that the area, for example, a double restriction with the communication passage 41 will be used. On the other hand, when this structure is embodied, it is necessary to divide the high-pressure seal portion 21 and the low-pressure seal portion 22 which are mating parts in order to accommodate the valve body 3 in the valve chamber 2, and usually both parts are positioned with a knock pin. However, it is necessary to give tolerances to the knock hole position and inner diameter, the outer diameter of the knock pin, and the like. For this reason, as shown in FIG. 3 (a), in the actual assembled state, an axial deviation occurs in which the shaft centers of the high pressure seal portion 21 and the low pressure seal portion 22 do not coincide with each other within the tolerance range. Moreover, in the structure which pushes the valve body 3 with the pin member 7, there exists a limit in the processing precision of both contact surfaces, for example, there exists a possibility that the valve body 3 may incline by an inclination of several micrometers.

この状態で、高圧シール部２１開弁時に、流体力等により弁体３が回転すると、上記図７（ｃ）に示した通り、従来の制御弁構造では、絞り部となる高圧ポート１０２出口部の面積Ｓが変動する。すると、図４に示すように、回転位置に応じてシート部開口面積が変化し、高圧ポート１０２から弁室１０４、さらには連通路４１を経てノズル背圧室４への燃料流入量が周期的に変化することにより、ノズルニードル５の閉弁速度が変動する。例えば、制御弁の弁体リフトは、通常２０μｍ程度であり、弁体上下面は数μｍの傾斜でも、軸ずれと弁体回転により、シート開口面積は大きく変化することになる。このため目標とする噴射量に対して実際の噴射量が増減し、安定した噴射量を供給することが困難である。 In this state, when the valve body 3 is rotated by a fluid force or the like when the high pressure seal portion 21 is opened, in the conventional control valve structure, as shown in FIG. The area S of fluctuates. Then, as shown in FIG. 4, the seat opening area changes according to the rotational position, and the amount of fuel flowing from the high pressure port 102 to the nozzle back pressure chamber 4 via the valve chamber 104 and further the communication path 41 is periodically changed. By changing to, the valve closing speed of the nozzle needle 5 varies. For example, the valve lift of the control valve is normally about 20 μm, and even if the valve body upper and lower surfaces are inclined by several μm, the seat opening area greatly changes due to the shaft misalignment and the valve body rotation. For this reason, the actual injection amount increases or decreases with respect to the target injection amount, and it is difficult to supply a stable injection amount.

これに対して本発明では、上記図１（ｂ）のように、弁体３の高圧シール部２１側に、座ぐり部３４を設け、かつＳ１（座ぐり周長さＬ１×弁体リフトＨ１）＜Ｓ２（高圧ポート周長さＬ２×（弁体リフトＨ１＋座ぐり深さＤ１））となる構成としたので、流路面積Ｓ１が高圧シール部２１開弁時の絞り部となり、高圧シール部と低圧シール部の位置ずれをキャンセルすることができる。図３（ａ）に示すように、高圧シール部２１と低圧シール部２２の軸心にずれが生じ、さらに弁体３が傾いて下端面の低圧シート部３１と対向する低圧シール部２１との位置ずれが発生した場合でも、図３（ｂ）に示すように、高圧シール部２１開弁時の絞り部となる流路面積Ｓ１は、弁体が１８０°回転しても変化しない。この構造により上記図５に示したノズル背圧室４の燃料流入量、ノズルニードル閉弁速度の周期的な変化を抑制し、安定した燃料噴射を可能とする。 On the other hand, in the present invention, as shown in FIG. 1B, a counterbore portion 34 is provided on the high pressure seal portion 21 side of the valve body 3, and S1 (counterbore circumferential length L1 × valve body lift H1). ) <S2 (high-pressure port circumferential length L2 × (valve lift H1 + counterbore depth D1)). Therefore, the flow passage area S1 becomes a throttle portion when the high-pressure seal portion 21 is opened, and the high-pressure seal portion And the position shift of the low pressure seal part can be canceled. As shown in FIG. 3 (a), the shaft centers of the high pressure seal portion 21 and the low pressure seal portion 22 are displaced, and the valve body 3 is further inclined with respect to the low pressure seal portion 21 facing the low pressure seat portion 31 on the lower end surface. Even when the position shift occurs, as shown in FIG. 3B, the flow passage area S1 that becomes the throttle portion when the high-pressure seal portion 21 is opened does not change even if the valve body rotates 180 °. This structure suppresses periodic changes in the fuel inflow amount and nozzle needle closing speed of the nozzle back pressure chamber 4 shown in FIG. 5 and enables stable fuel injection.

なお、高圧シール部２１と低圧シール部２２の位置ずれや弁体３の傾きを有する状態で、再び高圧シール部２１を閉弁する場合、図５（ａ）に示すように、まず、弁体３の一部のみが高圧シール部２１に当接する。この時点で、高圧ポート２３は完全には閉鎖されていない。次いで、この当接部が支点となり、弁体３頂面のピン部材７との当接部が力点となって、弁体３が回転すると、図５（ｂ）に示すように、シート可能な位置に弁体がずれ、高圧ポート２３を閉鎖することができる。このように、支点より力点が中心側にあればシート可能方向に回転力が作用するため、シート可能と考えられる。また、図は実際よりもずれを強調した模式的な図であり、噴射特性への影響はほとんどない。 When the high-pressure seal portion 21 is closed again in a state where the high-pressure seal portion 21 and the low-pressure seal portion 22 are misaligned or the valve body 3 is inclined, as shown in FIG. Only a part of 3 comes into contact with the high-pressure seal portion 21. At this point, the high pressure port 23 is not completely closed. Next, the contact portion becomes a fulcrum, and the contact portion with the pin member 7 on the top surface of the valve body 3 serves as a power point. When the valve body 3 rotates, as shown in FIG. The valve body is displaced to the position, and the high pressure port 23 can be closed. In this way, if the force point is closer to the center than the fulcrum, the rotational force acts in the seatable direction, so it is considered that seating is possible. Further, the figure is a schematic diagram in which the deviation is emphasized more than the actual, and there is almost no influence on the injection characteristics.

また、弁室２からノズル背圧室４への流入通路において、高圧シート部の流路面積Ｓ１が最小絞り部となる構成であれば、本発明の効果が大きいことは上述した通りであるが、ノズル背圧室４への流入通路が２重絞りとなる構成であってもよい。この場合、好適には、絞り部となる流路面積Ｓ１以外の流入通路の最小断面積、本実施形態では連通路４１の断面積をＳ３とした時に、高圧シート部の流路面積Ｓ１との関係が、下記式（４）を満足するように構成するとよい。
式（４）：Ｓ１／Ｓ３＜２ Further, as described above, if the flow passage area S1 of the high-pressure seat portion is the minimum throttle portion in the inflow passage from the valve chamber 2 to the nozzle back pressure chamber 4, the effect of the present invention is great. The inflow passage to the nozzle back pressure chamber 4 may be a double throttle. In this case, preferably, when the minimum cross-sectional area of the inflow passage other than the flow passage area S1 serving as the throttle portion, in this embodiment, the cross-sectional area of the communication passage 41 is S3, the flow passage area S1 of the high-pressure sheet portion It is preferable that the relationship satisfies the following formula (4).
Formula (4): S1 / S3 <2

図６（ａ）は、燃料噴射終了時（高圧側開弁時）の、高圧通路１２から、燃料溜まり室５２、高圧ポート２３、高圧シート２１、弁室２、連通路４１を経てノズル背圧室４へ流入する燃料の流れを示しており（図中、矢印）、図６（ｂ）は、流路面積Ｓ１を変化させた時（その他の通路面積は固定とする）の流量変化と、その他通路最小面積Ｓ３に対する面積比との関係を示している。図示のように、流路面積Ｓ１以外の燃料通路の最小面積Ｓ３に対し、流路面積Ｓ１が２倍（面積比２）程度までは、面積比が大きくなるほど流量が増加しており、面積比に対する流量変化が大きい。すなわち、ノズル背圧室４への流量への感度が高いため、弁体３が傾いて流量が変化した時の影響が大きく、本発明の効果が得られる。   6A shows the nozzle back pressure from the high pressure passage 12 through the fuel reservoir chamber 52, the high pressure port 23, the high pressure seat 21, the valve chamber 2, and the communication passage 41 at the end of fuel injection (when the high pressure side valve is open). FIG. 6B shows the flow of fuel flowing into the chamber 4 (arrow in the figure), and FIG. 6B shows the flow rate change when the flow path area S1 is changed (the other passage areas are fixed); The relationship with the area ratio with respect to other channel | path minimum area S3 is shown. As shown in the figure, the flow rate increases as the area ratio increases until the flow area S1 is about twice (area ratio 2) with respect to the minimum area S3 of the fuel passage other than the flow area S1. The flow rate change with respect to is large. That is, since the sensitivity to the flow rate to the nozzle back pressure chamber 4 is high, the influence when the valve body 3 is inclined and the flow rate is changed is large, and the effect of the present invention can be obtained.

以上により、本発明によれば、３方弁構造の制御弁において、加工精度や組付けのずれ、弁体の回転が生じても、燃料流入量の変動が抑制され、制御圧の変動を抑制することができる。よって、背圧式のインジェクタ等に利用されてノズルニードルの閉弁速度、噴射終了タイミングを安定させ、噴射量を安定して制御することができる。   As described above, according to the present invention, in a control valve having a three-way valve structure, even if machining accuracy, assembly deviation, or valve body rotation occurs, fluctuations in fuel inflow are suppressed, and fluctuations in control pressure are suppressed. can do. Therefore, it is utilized for a back pressure type injector or the like, and the valve closing speed of the nozzle needle and the injection end timing can be stabilized, and the injection amount can be controlled stably.

上記実施形態では、駆動力伝達機構に大径のピエゾピストンと小径のバルブピストンを用いたが、これら両ピストンを同径とすることもでき、油圧を介して安定して駆動力を伝達することができる。この場合、変位を拡大して伝達できるので、より効率よく動力を伝達することができる。また、アクチュエータは、通電により変位を発生する素子であれば、上記実施形態で使用したピエゾ素子以外の素子を用いてもよい。その他、本発明の制御弁を、インジェクタ以外の圧力制御に使用することもできる。   In the above embodiment, a large-diameter piezo piston and a small-diameter valve piston are used for the driving force transmission mechanism. However, both the pistons can have the same diameter, and the driving force can be stably transmitted via hydraulic pressure. Can do. In this case, the displacement can be enlarged and transmitted, so that the power can be transmitted more efficiently. In addition, the actuator may be an element other than the piezoelectric element used in the above embodiment as long as it is an element that generates displacement when energized. In addition, the control valve of the present invention can also be used for pressure control other than the injector.

（ａ）は本発明の第１の実施形態における制御弁の全体構成を示す図であり、（ｂ）は（ａ）の部分拡大断面図である。(A) is a figure which shows the whole structure of the control valve in the 1st Embodiment of this invention, (b) is the elements on larger scale of (a). 第１の実施形態における制御弁の作動を説明するための図で、（ａ）は低圧側シートが開弁している状態を示す図、（ｂ）は高圧側シートが閉弁している状態を示す図である。It is a figure for demonstrating the action | operation of the control valve in 1st Embodiment, (a) is a figure which shows the state which the low-pressure side seat is opening, (b) is the state where the high-pressure side seat is closed FIG. 本発明の効果を説明するための図で、（ａ）は制御弁の全体構成を示す図、（ｂ）は（ａ）の部分拡大断面図である。It is a figure for demonstrating the effect of this invention, (a) is a figure which shows the whole structure of a control valve, (b) is the elements on larger scale of (a). 従来の制御弁による作動と、噴射量変動の影響を説明するための図である。It is a figure for demonstrating the effect | action of the action | operation by the conventional control valve, and injection amount fluctuation | variation. 第１の実施形態における制御弁の作動を説明するための図で、（ａ）は噴射時の弁体の作動を示す図、（ｂ）は弁体が高圧シートを閉鎖した状態を示す図である。It is a figure for demonstrating the action | operation of the control valve in 1st Embodiment, (a) is a figure which shows the action | operation of the valve body at the time of injection, (b) is a figure which shows the state which the valve body closed the high pressure sheet | seat. is there. （ａ）はインジェクタの全体構成図、（ｂ）は燃料通路絞り部の面積比と流量の関係を示す図である。(A) is a whole block diagram of an injector, (b) is a figure which shows the relationship between the area ratio and flow volume of a fuel path throttle part. （ａ）、（ｂ）は従来のインジェクタの全体構成を示す断面図、（ｃ）はその部分拡大断面図である。(A), (b) is sectional drawing which shows the whole structure of the conventional injector, (c) is the partial expanded sectional view.

符号の説明Explanation of symbols

Ｈ ハウジング部材
Ｉ インジェクタ
Ｖ 制御弁
１ ピエゾスタック（アクチュエータ）
１１ 燃料導入口
１２ 高圧通路
１３ 低圧通路
１４ 燃料導出口
２ 弁室
２１ 高圧シール部
２２ 低圧シール部
２３ 高圧ポート
２４ 低圧ポート
３ 弁体
３１ 高圧シート部
３２ 低圧シート部
４ ノズル背圧室（制御室）
４１ 連通路
５ ノズルニードル
５２ 油溜まり室
５４ 噴孔
６ 駆動力伝達機構
６２ ピエゾピストン（ピストン部材）
６３ 油密室
６４ バルブピストン（ピストン部材）
７ ピン部材 H Housing member I Injector V Control valve 1 Piezo stack (actuator)
DESCRIPTION OF SYMBOLS 11 Fuel inlet 12 High pressure passage 13 Low pressure passage 14 Fuel outlet 2 Valve chamber 21 High pressure seal portion 22 Low pressure seal portion 23 High pressure port 24 Low pressure port 3 Valve body 31 High pressure seat portion 32 Low pressure seat portion 4 Nozzle back pressure chamber (control chamber) )
41 communication path 5 nozzle needle 52 oil reservoir chamber 54 nozzle hole 6 driving force transmission mechanism 62 piezo piston (piston member)
63 Oiltight chamber 64 Valve piston (piston member)
7 Pin member

Claims (7)

アクチュエータで駆動されるピストン部材が、弁室内に配置された弁体を軸方向に駆動して、上記弁室の対向面に設けた高圧シール部および低圧シール部の一方に選択的に着座させることにより、上記高圧シール部に連通する高圧ポートおよび上記低圧シール部に連通する低圧ポートを開閉して、上記弁室と常時連通する制御室の制御圧力を増減する制御弁であって、
上記弁体は、駆動方向の一方の端部に、上記高圧シール部に着座する高圧シート部を設け、他方の端部に、上記低圧シール部に着座する低圧シート部を設けるとともに、上記高圧シート部が形成される上記一方の端部には、上記高圧ポートの対向位置を凹陥させた座ぐり部を形成して、該座ぐり部の開口縁部が着座時の高圧シート位置となり、かつ、高圧シート径＞高圧ポート径となる形状としたことを特徴とする制御弁。 The piston member is driven by the actuator drives the valve body disposed in the valve chamber in the axial direction, thereby selectively seated on one of the high-pressure seal portion and the low-pressure seal portion provided on the opposite face of the valve chamber Accordingly, a control valve which opens and closes the low-pressure port, for increasing or decreasing the control pressure in the control chamber which always communicates with said valve chamber communicating with the high pressure port and the low-pressure seal portion communicating with the high-pressure seal portion,
The valve body is provided with a high-pressure seat portion seated on the high-pressure seal portion at one end in the driving direction, and a low-pressure seat portion seated on the low-pressure seal portion at the other end, and the high-pressure seat A counterbore part in which the opposite position of the high-pressure port is recessed is formed at the one end where the part is formed, and the opening edge of the counterbore part becomes a high-pressure seat position at the time of sitting, and A control valve characterized by having a shape such that the high-pressure seat diameter> the high-pressure port diameter. 上記弁体は、上記座ぐり部開口縁部の周長さをＬ１、上記座ぐり部の深さをＤ１、上記高圧ポート開口縁部の周長さをＬ２、上記高圧ポート開放時の上記弁体のリフト量をＨ１とした時に、下記式（１）〜（３）が成立する構成とした請求項１記載の制御弁。
式（１）：Ｓ１＝Ｌ１×Ｈ１
式（２）：Ｓ２＝Ｌ２×（Ｈ１＋Ｄ１）
式（３）：Ｓ１＜Ｓ２ The valve body has a circumferential length of the counterbore portion opening edge of L1, a depth of the counterbore portion of D1, a circumferential length of the high pressure port opening edge portion of L2, and the valve when the high pressure port is opened. The control valve according to claim 1, wherein the following formulas (1) to (3) are established when the lift amount of the body is H1.
Formula (1): S1 = L1 × H1
Formula (2): S2 = L2 × (H1 + D1)
Formula (3): S1 <S2 上記高圧シート位置を除く、上記制御室への流入通路の最小断面積をＳ３とした時に、下記式（４）が成立する構成とした請求項２記載の制御弁。
式（４）：Ｓ１／Ｓ３＜２ The control valve according to claim 2, wherein when the minimum cross-sectional area of the inflow passage to the control chamber excluding the high-pressure seat position is S3, the following expression (4) is established.
Formula (4): S1 / S3 <2 上記弁体は、上記一方の端部側の低圧シート部が球面または円錐状に形成されて、円錐状に形成された上記低圧シール部に対向する一方、上記他方の端部側の高圧シート部が平面状に形成されて、平面状に形成された上記高圧シール部に対向している請求項１ないし３のいずれか記載の制御弁。 In the valve body, the low-pressure seat portion on the one end side is formed in a spherical shape or a conical shape, and faces the low-pressure seal portion formed in the conical shape, while the high-pressure seat portion on the other end side 4. The control valve according to claim 1, wherein the control valve is formed in a planar shape and faces the high-pressure seal portion formed in a planar shape. 上記弁体は、上記座ぐり部の内周面が上記一方の端部に向けて拡径するテーパ面形状を有し、該テーパ面の傾斜角度が３０°以上９０°未満である請求項１ないし４のいずれか記載の制御弁。   The valve body has a tapered surface shape in which an inner peripheral surface of the counterbore portion expands toward the one end portion, and an inclination angle of the tapered surface is 30 ° or more and less than 90 °. 5. The control valve according to any one of 4 to 4. 上記アクチュエータがピエゾ式アクチュエータである請求項１ないし５のいずれか記載の制御弁。   6. The control valve according to claim 1, wherein the actuator is a piezo actuator. 請求項１ないし６のいずれか記載の制御弁を用いたインジェクタであって、上記制御室の圧力を、噴孔を開閉するノズルニードルの閉弁方向に作用させ、上記アクチュエータが上記ピストン部材を介して上記弁体を開閉することにより燃料噴射を行うことを特徴とするインジェクタ。   The injector using the control valve according to any one of claims 1 to 6, wherein the pressure in the control chamber is applied in a valve closing direction of a nozzle needle that opens and closes the nozzle hole, and the actuator is interposed via the piston member. An injector for performing fuel injection by opening and closing the valve body.
JP2008057392A 2008-03-07 2008-03-07 Control valves and injectors Expired - Fee Related JP4670878B2 (en)

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DE102013212259A1 (en) * 2013-06-26 2014-12-31 Robert Bosch Gmbh Fuel injection valve for internal combustion engines
JP6926836B2 (en) * 2017-08-30 2021-08-25 株式会社Ｓｏｋｅｎ Fuel injection device
JP7006161B2 (en) 2017-11-15 2022-01-24 株式会社Soken Fuel injection device

Citations (6)

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Publication number Priority date Publication date Assignee Title
JPH05133296A (en) * 1990-10-31 1993-05-28 Elasis Sistema Ric Fiat Nel Mezzogiorno Soc Consortile Per Azioni Electromagnetic type internal combustion engine fuel injector
JPH10122082A (en) * 1996-09-02 1998-05-12 Denso Corp Accumulative fuel injector
JP2004519602A (en) * 2001-05-08 2004-07-02 ローベルト　ボツシユ　ゲゼルシヤフト　ミツト　ベシユレンクテル　ハフツング Pressure-controlled control unit with reduced leakage
JP2006046323A (en) * 2004-07-06 2006-02-16 Denso Corp Common-rail injector
JP2006291856A (en) * 2005-04-12 2006-10-26 Denso Corp Fuel injection valve
JP2007231737A (en) * 2006-02-27 2007-09-13 Denso Corp Driving force transmission device and fuel injection device

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH05133296A (en) * 1990-10-31 1993-05-28 Elasis Sistema Ric Fiat Nel Mezzogiorno Soc Consortile Per Azioni Electromagnetic type internal combustion engine fuel injector
JPH10122082A (en) * 1996-09-02 1998-05-12 Denso Corp Accumulative fuel injector
JP2004519602A (en) * 2001-05-08 2004-07-02 ローベルト　ボツシユ　ゲゼルシヤフト　ミツト　ベシユレンクテル　ハフツング Pressure-controlled control unit with reduced leakage
JP2006046323A (en) * 2004-07-06 2006-02-16 Denso Corp Common-rail injector
JP2006291856A (en) * 2005-04-12 2006-10-26 Denso Corp Fuel injection valve
JP2007231737A (en) * 2006-02-27 2007-09-13 Denso Corp Driving force transmission device and fuel injection device

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