WO2014077072A1 - Common rail - Google Patents

Common rail Download PDF

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Publication number
WO2014077072A1
WO2014077072A1 PCT/JP2013/077888 JP2013077888W WO2014077072A1 WO 2014077072 A1 WO2014077072 A1 WO 2014077072A1 JP 2013077888 W JP2013077888 W JP 2013077888W WO 2014077072 A1 WO2014077072 A1 WO 2014077072A1
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WIPO (PCT)
Prior art keywords
common rail
branch
hole
fuel
branch hole
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PCT/JP2013/077888
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French (fr)
Japanese (ja)
Inventor
直人 平沼
稔 松崎
久保　賢一
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ボッシュ株式会社
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Publication of WO2014077072A1 publication Critical patent/WO2014077072A1/en

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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
    • F02M55/00—Fuel-injection apparatus characterised by their fuel conduits or their venting means; Arrangements of conduits between fuel tank and pump F02M37/00
    • F02M55/02—Conduits between injection pumps and injectors, e.g. conduits between pump and common-rail or conduits between common-rail and injectors
    • F02M55/025—Common rails
    • 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
    • F02M2200/03—Fuel-injection apparatus having means for reducing or avoiding stress, e.g. the stress caused by mechanical force, by fluid pressure or by temperature variations

Definitions

  • the present invention relates to a common rail used in an accumulator fuel supply device for an internal combustion engine such as a diesel engine.
  • An accumulator fuel supply device is known as a device for supplying fuel to an internal combustion engine such as a diesel engine.
  • the accumulator fuel supply device includes a common rail capable of storing high-pressure fuel, a plurality of injectors connected to the common rail via piping, and a fuel supply pump that pressurizes high-pressure fuel into the common rail via piping. These are electronically controlled by a control device so that high-pressure fuel can be precisely injected from each injector into each cylinder of the internal combustion engine.
  • the common rail used in the accumulator fuel supply device has a fuel storage hole that is a cylindrical space that can store high-pressure fuel provided inside the common rail main body, and the fuel storage hole faces the outside of the common rail main body. It has a branch hole that branches off.
  • An injector and a fuel supply pump are connected to the branch hole of the common rail main body through a connecting member and piping, and other sensors such as a pressure sensor and a temperature sensor, and valves such as a pressure control valve and a pressure limiter are also connected.
  • the common rail is configured to include a number of branch holes.
  • Patent Document 1 discloses an auto-fretage process (auto-fretage process in the document) that can withstand a tensile stress by applying a compressive residual stress to the internal surface of the common rail body in advance. ing.
  • auto-fretage processing applies compression to the fuel rails inside the common rail body, elastically deforms the entire common rail body, and plastically deforms the inner surface of the common rail body, thereby compressing and remaining on the inner surface of the common rail body.
  • stress depending on the shape of the common rail body, it may be difficult to deform or may not be uniformly deformed.
  • compressive residual stress cannot be applied to the inner surface of the common rail body, or compressive residual stress cannot be applied uniformly.
  • FIG. 4 (a) is a perspective view of a conventional common rail 300
  • FIG. 4 (b) is a diagram (cut-off view) of a cut surface viewed from the axial direction of the common rail main body 310 along the line BB ′ shown in the perspective view. Thick cross-sectional view) is shown.
  • the common rail 300 includes a common rail body 310, an upper connection member 330, a lower connection member 331, a pressure sensor 340, a pressure control valve 350, and a fuel discharge pipe 360.
  • the common rail main body 310 is integrally formed in a shape in which a flat plate-shaped sealing surface portion 317 including a flange portion 315 is combined with an upper side of a columnar rail.
  • the flange portion 315 is provided with a through hole 316 into which a fixing bolt for attaching the common rail 300 to the engine can be inserted.
  • the seal surface portion 317 is finished flat to enable sealing with the mounting surface of the engine.
  • An upper branch hole 312 branched from the fuel storage hole 311 is opened in the seal surface part 317, and an upper branch hole connection part 312a that allows the upper connection member 330 to be fastened is provided in the opening part.
  • a boss portion 314 having a lower branch hole 313 is provided on the lower side of the common rail body 310 opposite to the seal surface portion 317, and the lower connection member 331 can be fastened to the opening portion of the lower branch hole 313.
  • a lower branch hole connecting portion 313a is provided.
  • the thickness around the upper branch hole 312 including the seal surface portion 317 including the flange portion 315 is the thickness around the lower branch hole 313. Since it is thicker than the thickness, even if a high pressure is applied during auto-fretage processing, deformation does not easily occur around the upper branch hole 312. As a result, there is a problem that sufficient compressive residual stress cannot be applied to the periphery of the opening of the upper branch hole 312 of the fuel storage hole 311.
  • the common rail 300 having the above-described shape, when auto-fretage processing is performed at an ultrahigh pressure in order to give sufficient compressive residual stress around the opening of the upper branch hole 312, even if the entire inner surface of the common rail main body 310 is applied Even if a sufficient compressive residual stress can be applied, the upper surface of the common rail body 310 that is provided with the seal surface portion 317 including the flange portion 315 and has a large thickness, and the common rail body that is not thick. Below 310, there is a problem that the degree of deformation differs and plastic deformation occurs so that the entire common rail is warped.
  • the fuel storage hole that is a cylindrical space that is provided inside the rail body and can store high-pressure fuel
  • the plurality of branch holes that branch from the fuel storage hole toward the outside of the rail body are provided.
  • the branch hole is divided into two directions when viewed from the axial direction of the fuel storage hole, and the central axis of the branch hole branching in one direction and the branch hole branching in the other direction are mutually
  • a common rail characterized by being arranged at an angle not facing each other is provided to solve the above-described problems.
  • the central axis of the branch hole branching in one direction and the branch hole branching in the other direction be provided one by one on the same wall section of the common rail body.
  • the central axis of the branch hole branched in one direction and the branch hole branched in the other direction may be arranged at an angle perpendicular to the radial direction of the fuel storage hole. desirable.
  • the central axis of the branch hole is shifted to a position eccentric with respect to the axis of the fuel storage hole.
  • the branch hole is divided into two directions when viewed from the axial direction of the fuel storage hole, and the central axis of the branch hole that branches in one direction and the branch hole that branches in the other direction Are arranged at angles that do not oppose each other.
  • the central axes of the branch holes that branch in one direction and the branch holes that branch in the other direction are parallel to each other or on the same straight line. Arranged so as not to be in a positional relationship. For this reason, the fuel reservoir hole is distorted by the pressure of the axial force received on the pressure receiving seating surface of the branch hole connecting portion when the connecting member or the pipe is fastened to the branch hole connecting portion of the branch hole branching in one or the other direction. Deformation is suppressed.
  • the central axis of the branch hole branching in one direction and the branch hole branching in the other direction are arranged one by one on the same thickness section of the common rail body, Since the bifurcated holes in both directions are paired and the distorted deformation of the fuel reservoir hole is effectively suppressed, the generation of tensile stress around the branch hole opening of the fuel reservoir hole can be suppressed.
  • the central axis of the branch hole branched in one direction and the branch hole branched in the other direction are arranged at an angle orthogonal to the radial direction of the fuel storage hole.
  • the pressure of the axial force received on the pressure receiving seating surface of the branch hole connecting portion when the connecting member or the pipe is fastened to the branch hole connecting portion of both branch holes is not applied in the direction of sandwiching the fuel storage hole and both branches. It is possible to sufficiently escape to the side where the holes are wide. Therefore, it is possible to effectively suppress the distorted deformation of the fuel storage hole and reliably suppress the generation of tensile stress around the branch hole opening of the fuel storage hole.
  • the edge portion of the branch hole opening portion of the fuel storage hole is configured such that the central axis of the branch hole is shifted to a position eccentric with respect to the axis of the fuel storage hole. Since it deviates from the center position of the fuel reservoir hole, stress concentration is suppressed and the starting point of the crack can be eliminated.
  • the common rail 100 of the present invention will be described with reference to FIG. 1A is a perspective view of the common rail 100 of the present invention, and FIG. 1B is a cross-sectional view of the common rail main body 110 taken along the line AA ′ in the perspective view ( (Thickness cross-sectional view) is shown.
  • the common rail 100 includes a common rail main body 110, a sealing member 120, a vertical connection member 130, a horizontal connection member 131, a pressure sensor 140, a pressure control valve 150, and a fuel discharge pipe 160.
  • the common rail main body 110 is made of a metal made of high carbon steel or the like, and a fuel storage hole 111 penetrating in the longitudinal direction of the common rail main body 110 is provided therein. And the common rail main body 110 forms the cylindrical space inside by closing the opening part of the both ends of the fuel storage hole 111 with the sealing member 120, and can store a high pressure fuel.
  • the common rail body 110 has a plurality of branch holes divided from the fuel storage holes 111 of the common rail body 110 in two directions when viewed from the axial direction of the fuel storage holes 111 (the direction indicated by the arrow X in FIG. 1A).
  • the common rail body 110 is provided so as to open on the outer surface.
  • the branch holes of the common rail 100 according to the present embodiment are divided into a vertical branch hole and a horizontal branch hole, and the vertical branch hole 112 corresponds to a branch hole that branches in one direction.
  • the lateral branch hole 113 corresponds to a branch hole that branches in the other direction.
  • the longitudinal branch hole 112 is disposed at an angle orthogonal to the seal surface portion 117 that becomes a seal surface when the common rail main body 110 is attached to the engine, and is provided to open at the seal surface portion 117.
  • the longitudinal branch hole 112 has an enlarged longitudinal branch hole connection portion 112 a that enables fastening of the longitudinal connection member 130.
  • the common rail main body 110 is provided with four vertical branch holes 112 in parallel along the axis of the fuel storage hole 111, and a vertical connection member 130 is fastened to each of the common rail main bodies 110 by screw coupling.
  • the vertical connection member 130 is provided with a screw portion that enables connection of a fuel pipe (not shown) at the end opposite to the fastening side of the vertical branch hole connection portion 112a. Then, high-pressure fuel is supplied from the common rail 100 to each injector (not shown) via a fuel pipe (not shown) connected to each vertical connection member 130.
  • the lateral branch holes 113 are provided so as to open to four boss portions 114 formed integrally on the side surface of the common rail main body 110. Similar to the longitudinal branch hole 112, the lateral branch hole 113 has a lateral branch hole connection portion 113 a to which the lateral connection member 131 can be fastened, and the lateral connection member 131 is attached thereto.
  • the lateral connection member 131 is fastened to the two lateral branch hole connection portions 113 a, and the fuel supply pump is connected via a fuel pipe (not shown) connected to the two lateral connection members 131. High-pressure fuel is supplied from the inside (not shown) into the common rail 100.
  • the lateral branch hole connecting portions 113a of the remaining two lateral branch holes 113 are provided with a pressure sensor 140 for measuring the fuel pressure in the common rail 100 and a control device (in order to adjust the fuel pressure in the common rail 100).
  • a pressure control valve 150 that is electronically controlled by an unillustrated) is fastened.
  • a fuel discharge pipe 160 for the fuel discharged to adjust the fuel pressure is attached to the boss portion 114 to which the pressure control valve 150 is fastened.
  • the longitudinal branch hole 112 and the lateral branch hole 113 are respectively centered on the same thick section of the rail body 110.
  • the fuel storage holes 111 are arranged at an angle orthogonal to the radial direction.
  • FIG. 2 schematically shows the result of simulating the deformation of the fuel storage hole when the pressure of the axial force generated when the connecting member is fastened to the branch hole connecting portion is applied to the common rail, in the thickness cross-sectional view of the common rail main body.
  • 2A shows a simulation result for the common rail 100 of the present embodiment shown in FIG. 1
  • FIG. 2B shows a simulation result for the conventional common rail 300 shown in FIG.
  • the branch holes 312 and 313 branching in two directions are vertically opposed to each other with the fuel storage hole 311 interposed therebetween, and their central axes are on the same straight line. Because of the positional relationship, the pressure of the axial force applied to the pressure receiving seat surfaces 312b and 313b of both branch holes 312 and 313 is the pressure indicated by the white arrow. And the pressure from the up-down direction of this fuel storage hole 311 becomes the force which deform
  • the branch hole of the common rail main body 110 is arranged so as to be orthogonal to the radial direction of the fuel storage hole 111.
  • the pressure of the axial force applied to the pressure receiving seat surfaces 112b and 113b of both the branch holes 112 and 113 is the pressure indicated by the white arrows. This pressure is not applied in the direction in which the fuel storage hole 111 is sandwiched, and escapes in the direction indicated by the wide black arrow between the two branch holes 112 and 113, so that the fuel storage hole 111 is connected to the conventional common rail 300. Since the fuel storage hole 311 is not greatly deformed in the left-right direction, the generation of tensile stress around the opening portions of both the branch holes 112 and 113 of the fuel storage hole 111 can be suppressed.
  • FIG. 3 is a cross-sectional view showing a wall thickness of a common rail body 210 according to a modification.
  • the branch hole small diameter portion 212c of the vertical branch hole 212 and the branch hole small diameter portion 213c of the horizontal branch hole 213 are different from the central axes of the branch hole connection portions 212a and 213a, respectively. have.
  • the central axes of both branch hole small-diameter portions 212 c and 213 c are arranged at positions eccentric from the axis C of the fuel storage hole 211.
  • the center axis of the branch hole connecting portions 212a and 213a is provided without being decentered with respect to the axis C of the fuel storage hole 211, and only the center axis of the branch hole small diameter portions 212c and 213c is translated.
  • the storage hole 211 is provided eccentrically with respect to the axis C.
  • the branch hole small diameter portions 212 c and 213 c are moved in parallel to each other to a position overlapping with a tangent in the cross-sectional circle of the fuel storage hole 211 parallel to the branch hole small diameter portions 212 c and 213 c due to eccentricity.
  • both branch hole small diameter portions 212c and 213c By arranging both branch hole small diameter portions 212c and 213c at the positions described above, the edge portions of the opening portions of both branch hole small diameter portions 212c and 213c of the fuel storage hole 211 are respectively located from the position of the center line of the fuel storage hole 211. It will come off. Thereby, the stress concentration at the edge portion is suppressed, and the starting point of the crack receiving the tensile stress from both the left and right directions is eliminated.
  • the common rail of the present invention by appropriately arranging the branch holes, the tensile stress generated around the branch hole opening of the fuel reservoir hole can be reduced, and the branch of the fuel reservoir hole can be reduced. Cracks generated at the edge portion of the hole opening can be prevented.
  • the branch hole that branches in one direction and the branch hole that branches in the other direction are positioned on the same thickness cross section of the common rail body, but it is not limited thereto.
  • the arrangement of the branch holes branching in the other direction in the longitudinal direction of the common rail may be arranged at a position while the branch holes branching in one direction are aligned in the longitudinal direction.
  • a plurality of branch holes that branch in one direction are all branched in the same vertical direction, and a plurality of branch holes that branch in the other direction are also branched in the same lateral direction.
  • the directions can be adjusted and provided according to the layout. If the directions are substantially the same, a uniform effect can be obtained.
  • the branch hole small diameter part and the branch hole connection part are configured to have different central axes, but the present invention is not limited thereto, and the branch hole small diameter part and the branch hole connection part are You may make it eccentric with respect to the axial center C of a fuel storage hole, making the center axis the same.

Abstract

Provided is a common rail that can prevent cracking in the edges of branched hole openings of a fuel retaining hole without performing autofrettage for applying compressive residual stress to an internal surface of a common rail main body. The common rail is characterized in comprising a fuel retaining hole which is a columnar space provided inside the rail main body and capable of retaining high-pressure fuel, and a plurality of branching holes that each branch out of the rail main body from the fuel retaining hole, wherein the branching directions of the branching holes are split in two directions as seen from the axial direction of the fuel retaining hole, and the center axes of the branching holes that branch in one direction and the branching holes that branch in the other direction are disposed at angles so as to not face each other.

Description

コモンレールCommon rail
　本発明は、ディーゼルエンジン等の内燃機関の蓄圧式燃料供給装置に用いられるコモンレールに関する。 The present invention relates to a common rail used in an accumulator fuel supply device for an internal combustion engine such as a diesel engine.
　ディーゼルエンジン等の内燃機関に燃料を供給する装置として蓄圧式燃料供給装置が公知である。蓄圧式燃料供給装置は、高圧の燃料を貯留可能なコモンレールと、コモンレールに配管を介して接続される複数のインジェクタと、コモンレール内へ配管を介して高圧の燃料を加圧供給する燃料供給ポンプを備え、それらを制御装置により電子制御することで高圧の燃料を各インジェクタから内燃機関の各気筒内へ緻密に噴射することを可能としている。 An accumulator fuel supply device is known as a device for supplying fuel to an internal combustion engine such as a diesel engine. The accumulator fuel supply device includes a common rail capable of storing high-pressure fuel, a plurality of injectors connected to the common rail via piping, and a fuel supply pump that pressurizes high-pressure fuel into the common rail via piping. These are electronically controlled by a control device so that high-pressure fuel can be precisely injected from each injector into each cylinder of the internal combustion engine.
　蓄圧式燃料供給装置に用いられるコモンレールは、コモンレール本体の内部に設けられた高圧の燃料を貯留可能な円柱状空間である燃料貯留孔を有し、この燃料貯留孔からコモンレール本体の外部に向かって分岐する分岐孔を備えている。コモンレール本体の分岐孔には、接続部材や配管を介してインジェクタや燃料供給ポンプが接続され、その他にも圧力センサーや温度センサー等のセンサー類および圧力制御弁、プレッシャーリミッター等のバルブ類も接続される。そのため、コモンレールは、数多くの分岐孔を備える構成となっている。 The common rail used in the accumulator fuel supply device has a fuel storage hole that is a cylindrical space that can store high-pressure fuel provided inside the common rail main body, and the fuel storage hole faces the outside of the common rail main body. It has a branch hole that branches off. An injector and a fuel supply pump are connected to the branch hole of the common rail main body through a connecting member and piping, and other sensors such as a pressure sensor and a temperature sensor, and valves such as a pressure control valve and a pressure limiter are also connected. The Therefore, the common rail is configured to include a number of branch holes.
　ところで、近年、環境問題の観点から大気汚染対策として自動車の排出ガス規制が厳しくなって来ている。蓄圧式燃料供給装置を用いるディーゼルエンジンにおいては、排出ガス規制への対応として蓄圧式燃料供給装置から供給される燃料の高圧化が進められている。供給燃料の高圧化に伴い、蓄圧式燃料供給装置では、構成部品である燃料供給ポンプやインジェクタおよびコモンレールの耐圧強化が課題とされている。 By the way, in recent years, automobile exhaust gas regulations have become stricter as a countermeasure against air pollution from the viewpoint of environmental problems. In a diesel engine using an accumulator fuel supply device, the pressure of fuel supplied from the accumulator fuel supply device is being increased in response to exhaust gas regulations. Along with the increase in the pressure of the supplied fuel, in the accumulator fuel supply device, there is a problem of strengthening the pressure resistance of the fuel supply pump, the injector, and the common rail which are constituent parts.
　コモンレールでは、貯留する燃料が高圧になると燃料貯留孔の分岐孔開口部のエッジ部分に亀裂が発生しやすくなり、亀裂から燃料漏れを招く恐れがあるため、この部分の耐圧強化が重要な課題である。 In the common rail, if the fuel to be stored becomes high pressure, cracks are likely to occur at the edge of the branch hole opening of the fuel reservoir hole, which may lead to fuel leakage from the crack. is there.
　燃料貯留孔の分岐孔開口部のエッジ部分における亀裂は、分岐孔接続部に締結する接続部材や配管の締付けに伴う分岐孔接続部の受圧座面に受ける軸力と、レール本体内にかかる燃料圧力とにより、燃料貯留孔の分岐孔開口部周辺に大きな引張り応力が発生し、これにより分岐孔開口部のエッジ部分を起点に亀裂が生じるものである。この問題の解決策として特許文献１には、予めコモンレール本体の内部表面に圧縮残留応力を付与することで引張り応力に耐えられるようにするオートフレタージュ加工（文献ではオートフレッテージ加工）が開示されている。 Cracks at the edge of the branch hole opening of the fuel reservoir hole are caused by the axial force received on the pressure receiving seating surface of the branch hole connection part when tightening the connection member and the pipe fastened to the branch hole connection part, and the fuel applied to the rail body Due to the pressure, a large tensile stress is generated in the vicinity of the branch hole opening of the fuel storage hole, whereby a crack is generated starting from the edge portion of the branch hole opening. As a solution to this problem, Patent Document 1 discloses an auto-fretage process (auto-fretage process in the document) that can withstand a tensile stress by applying a compressive residual stress to the internal surface of the common rail body in advance. ing.
特開２００２－３１００３４号公報JP 2002-310034 A
　しかしながら、オートフレタージュ加工は、コモンレール本体内部の燃料貯留孔に非常に高い圧力を加え、コモンレール本体全体を弾性変形させるとともにコモンレール本体の内部表面を塑性変形させることでコモンレール本体の内部表面に圧縮残留応力を付与することを可能としているが、コモンレール本体の形状によっては変形させることが困難な場合や均等に変形させられない場合がある。その結果、コモンレール本体の内部表面に圧縮残留応力を付与できない、または均一に圧縮残留応力を付与することができない等の問題があった。 However, auto-fretage processing applies compression to the fuel rails inside the common rail body, elastically deforms the entire common rail body, and plastically deforms the inner surface of the common rail body, thereby compressing and remaining on the inner surface of the common rail body. Although it is possible to apply stress, depending on the shape of the common rail body, it may be difficult to deform or may not be uniformly deformed. As a result, there has been a problem that compressive residual stress cannot be applied to the inner surface of the common rail body, or compressive residual stress cannot be applied uniformly.
　従来のコモンレールの問題について図４を参照して説明する。図４（ａ）は、従来のコモンレール３００の斜視図が示され、図４（ｂ）は、斜視図に記すＢ－Ｂ’線におけるコモンレール本体３１０の軸方向から見た切断面の図（肉厚断面図）が示されている。コモンレール３００は、コモンレール本体３１０と上側接続部材３３０と下側接続部材３３１と圧力センサー３４０と圧力制御弁３５０と燃料排出管３６０により構成されている。 The conventional common rail problem will be described with reference to FIG. 4 (a) is a perspective view of a conventional common rail 300, and FIG. 4 (b) is a diagram (cut-off view) of a cut surface viewed from the axial direction of the common rail main body 310 along the line BB ′ shown in the perspective view. Thick cross-sectional view) is shown. The common rail 300 includes a common rail body 310, an upper connection member 330, a lower connection member 331, a pressure sensor 340, a pressure control valve 350, and a fuel discharge pipe 360.
　コモンレール本体３１０は、円柱状のレールの上側にフランジ部３１５を含む平板状のシール面部３１７が合わせられたような形状に一体成形されている。フランジ部３１５には、コモンレール３００をエンジンへ取付けるための固定ボルトを挿入可能な貫通穴３１６が設けられている。シール面部３１７は、エンジンの取付け面とのシールを可能とするため平坦に仕上げられている。 The common rail main body 310 is integrally formed in a shape in which a flat plate-shaped sealing surface portion 317 including a flange portion 315 is combined with an upper side of a columnar rail. The flange portion 315 is provided with a through hole 316 into which a fixing bolt for attaching the common rail 300 to the engine can be inserted. The seal surface portion 317 is finished flat to enable sealing with the mounting surface of the engine.
　シール面部３１７には燃料貯留孔３１１から分岐した上側分岐孔３１２が開口し、その開口部には上側接続部材３３０の締結を可能とする上側分岐孔接続部３１２ａが設けられている。シール面部３１７とは反対側のコモンレール本体３１０の下側には下側分岐孔３１３が開口するボス部３１４が備えられ、下側分岐孔３１３の開口部にも下側接続部材３３１の締結を可能とする下側分岐孔接続部３１３ａが設けられている。 An upper branch hole 312 branched from the fuel storage hole 311 is opened in the seal surface part 317, and an upper branch hole connection part 312a that allows the upper connection member 330 to be fastened is provided in the opening part. A boss portion 314 having a lower branch hole 313 is provided on the lower side of the common rail body 310 opposite to the seal surface portion 317, and the lower connection member 331 can be fastened to the opening portion of the lower branch hole 313. A lower branch hole connecting portion 313a is provided.
　図４（ｂ）のコモンレール本体３１０の肉厚断面図に示されるように、フランジ部３１５を含むシール面部３１７を備える上側分岐孔３１２の周囲の肉厚は、下側分岐孔３１３の周囲の肉厚に比べ厚くなっているため、オートフレタージュ加工時に高い圧力を加えても上側分岐孔３１２の周囲では変形がおきにくい。その結果、燃料貯留孔３１１の上側分岐孔３１２の開口部周辺に十分な圧縮残留応力を付与することができない問題があった。 As shown in the thickness cross-sectional view of the common rail main body 310 in FIG. 4B, the thickness around the upper branch hole 312 including the seal surface portion 317 including the flange portion 315 is the thickness around the lower branch hole 313. Since it is thicker than the thickness, even if a high pressure is applied during auto-fretage processing, deformation does not easily occur around the upper branch hole 312. As a result, there is a problem that sufficient compressive residual stress cannot be applied to the periphery of the opening of the upper branch hole 312 of the fuel storage hole 311.
　また、上述した形状のコモンレール３００において上側分岐孔３１２の開口部周辺に十分な圧縮残留応力を付与するために超高圧力でオートフレタージュ加工を施した場合、たとえコモンレール本体３１０の内部表面全体に十分な圧縮残留応力を付与することが出来たとしても、フランジ部３１５を含むシール面部３１７が設けられて肉厚が厚くなっているコモンレール本体３１０の上側と、肉厚が厚くなっていないコモンレール本体３１０の下側では変形の度合いに違いが生じコモンレール全体が反るように塑性変形してしまうなどの問題があった。 Further, in the common rail 300 having the above-described shape, when auto-fretage processing is performed at an ultrahigh pressure in order to give sufficient compressive residual stress around the opening of the upper branch hole 312, even if the entire inner surface of the common rail main body 310 is applied Even if a sufficient compressive residual stress can be applied, the upper surface of the common rail body 310 that is provided with the seal surface portion 317 including the flange portion 315 and has a large thickness, and the common rail body that is not thick. Below 310, there is a problem that the degree of deformation differs and plastic deformation occurs so that the entire common rail is warped.
　本発明は、このような問題点に鑑み発明者が鋭意検討した結果、分岐孔の配置を適切に行うことにより、燃料貯留孔の分岐孔開口部のエッジ部分における亀裂の原因となる引張り応力を低減することができることを見出したものであり、コモンレール本体の内部表面に圧縮残留応力を付与するためのオートフレタージュ加工を施すことなしに燃料貯留孔の分岐孔開口部のエッジ部分に発生する亀裂を防止することのできるコモンレールを提供することを目的とする。　 In the present invention, as a result of the inventor's earnest examination in view of such problems, by appropriately arranging the branch holes, the tensile stress that causes cracks in the edge portion of the branch hole opening of the fuel reservoir hole is reduced. It has been found that it can be reduced, and cracks generated at the edge of the branch hole opening of the fuel reservoir hole without subjecting the internal surface of the common rail main body to auto-fretage processing for applying compressive residual stress It aims at providing the common rail which can prevent. *
　本発明によれば、レール本体内部に設けられ高圧の燃料を貯留可能な円柱状空間である燃料貯留孔と、燃料貯留孔からレール本体外部に向かってそれぞれ分岐する複数の分岐孔とを備えたコモンレールにおいて、分岐孔は、燃料貯留孔の軸方向から見たときに分岐方向が概ね２方向に分けられ、一方の方向に分岐する分岐孔と他方の方向に分岐する分岐孔の中心軸が互いに対向しない角度に配置されていることを特徴とするコモンレールが提供され上述した問題を解決することができる。 According to the present invention, the fuel storage hole that is a cylindrical space that is provided inside the rail body and can store high-pressure fuel, and the plurality of branch holes that branch from the fuel storage hole toward the outside of the rail body are provided. In the common rail, the branch hole is divided into two directions when viewed from the axial direction of the fuel storage hole, and the central axis of the branch hole branching in one direction and the branch hole branching in the other direction are mutually A common rail characterized by being arranged at an angle not facing each other is provided to solve the above-described problems.
　また、本発明のコモンレールを構成するにあたり、一方の方向に分岐する分岐孔と他方の方向に分岐する分岐孔の中心軸が、コモンレール本体の同一肉厚断面上に一つずつあることが望ましい。 Further, in configuring the common rail of the present invention, it is desirable that the central axis of the branch hole branching in one direction and the branch hole branching in the other direction be provided one by one on the same wall section of the common rail body.
　また、本発明のコモンレールを構成するにあたり、一方の方向へ分岐した分岐孔と他方の方向へ分岐した分岐孔の中心軸は、燃料貯留孔の径方向で直交する角度に配置されていることが望ましい。 Further, in configuring the common rail of the present invention, the central axis of the branch hole branched in one direction and the branch hole branched in the other direction may be arranged at an angle perpendicular to the radial direction of the fuel storage hole. desirable.
　また、本発明のコモンレールを構成するにあたり、分岐孔の中心軸が燃料貯留孔の軸心に対し偏心した位置にずらされて配置されていることが望ましい。 Further, in configuring the common rail of the present invention, it is desirable that the central axis of the branch hole is shifted to a position eccentric with respect to the axis of the fuel storage hole.
　本発明のコモンレールにおいて、分岐孔は燃料貯留孔の軸方向から見たときに分岐方向が概ね２方向に分けられ、一方の方向に分岐する分岐孔と他方の方向に分岐する分岐孔の中心軸が互いに対向しない角度に配置されている構成であり、換言すれば、一方の方向に分岐する分岐孔と他方の方向に分岐する分岐孔の中心軸が互いに平行な位置関係または同一直線上にある位置関係にならないように配置されている。そのため、一方と他方の方向に分岐する分岐孔の分岐孔接続部に接続部材や配管が締結されたときの分岐孔接続部の受圧座面に受ける軸力の圧力によっておきる燃料貯留孔のいびつな変形が抑えられる。したがって、燃料貯留孔の分岐孔開口部周辺で発生する引張り応力が低減され分岐孔開口部のエッジ部分に発生する亀裂を防止することができる。また、オートフレタージュ加工を施す必要がなくなることから、オートフレタージュ加工に伴う不具合も防止できる。さらに、オートフレタージュ加工のための高価な設備の導入や工数も不要となるため安価なコモンレールを提供することができる。 In the common rail of the present invention, the branch hole is divided into two directions when viewed from the axial direction of the fuel storage hole, and the central axis of the branch hole that branches in one direction and the branch hole that branches in the other direction Are arranged at angles that do not oppose each other. In other words, the central axes of the branch holes that branch in one direction and the branch holes that branch in the other direction are parallel to each other or on the same straight line. Arranged so as not to be in a positional relationship. For this reason, the fuel reservoir hole is distorted by the pressure of the axial force received on the pressure receiving seating surface of the branch hole connecting portion when the connecting member or the pipe is fastened to the branch hole connecting portion of the branch hole branching in one or the other direction. Deformation is suppressed. Therefore, the tensile stress generated around the branch hole opening of the fuel storage hole is reduced, and cracks occurring at the edge of the branch hole opening can be prevented. In addition, since it is not necessary to perform auto-fretage processing, problems associated with auto-fretage processing can be prevented. Furthermore, since it is not necessary to introduce expensive equipment and man-hours for auto-fretage processing, an inexpensive common rail can be provided.
　また、本発明のコモンレールにおいて、一方の方向に分岐する分岐孔と他方の方向に分岐する分岐孔の中心軸が、コモンレール本体の同一の肉厚断面上に一つずつある構成とすることで、両方向の分岐孔がそれぞれ一対となり燃料貯留孔のいびつな変形を効果的に抑えるため、燃料貯留孔の分岐孔開口部周辺での引張り応力の発生を抑えることができる。 Further, in the common rail of the present invention, the central axis of the branch hole branching in one direction and the branch hole branching in the other direction are arranged one by one on the same thickness section of the common rail body, Since the bifurcated holes in both directions are paired and the distorted deformation of the fuel reservoir hole is effectively suppressed, the generation of tensile stress around the branch hole opening of the fuel reservoir hole can be suppressed.
　また、本発明のコモンレールにおいて、一方の方向へ分岐した分岐孔と他方の方向へ分岐した分岐孔の中心軸は、燃料貯留孔の径方向で直交する角度に配置されている構成とすることで、両分岐孔の分岐孔接続部に接続部材や配管が締結されたときの分岐孔接続部の受圧座面に受ける軸力の圧力は、燃料貯留孔を挟む方向にかかることが無くなると共に両分岐孔間が広くあいた側へ十分に逃げることが可能となる。そのため、燃料貯留孔のいびつな変形を効果的に抑え燃料貯留孔の分岐孔開口部周辺での引張り応力の発生を確実に抑えることができる。 Further, in the common rail of the present invention, the central axis of the branch hole branched in one direction and the branch hole branched in the other direction are arranged at an angle orthogonal to the radial direction of the fuel storage hole. The pressure of the axial force received on the pressure receiving seating surface of the branch hole connecting portion when the connecting member or the pipe is fastened to the branch hole connecting portion of both branch holes is not applied in the direction of sandwiching the fuel storage hole and both branches. It is possible to sufficiently escape to the side where the holes are wide. Therefore, it is possible to effectively suppress the distorted deformation of the fuel storage hole and reliably suppress the generation of tensile stress around the branch hole opening of the fuel storage hole.
　また、本発明のコモンレールにおいて、分岐孔の中心軸が燃料貯留孔の軸心に対し偏心した位置にずらされて配置されている構成とすることで、燃料貯留孔の分岐孔開口部のエッジ部分は、燃料貯留孔の中心の位置から外れるため応力集中が抑えられ亀裂の起点を解消することができる。 In the common rail of the present invention, the edge portion of the branch hole opening portion of the fuel storage hole is configured such that the central axis of the branch hole is shifted to a position eccentric with respect to the axis of the fuel storage hole. Since it deviates from the center position of the fuel reservoir hole, stress concentration is suppressed and the starting point of the crack can be eliminated.
本発明のコモンレールの斜視図と断面図The perspective view and sectional drawing of the common rail of this invention 燃料貯留孔の歪みを説明するコモンレールの断面図Cross section of common rail explaining fuel storage hole distortion 本発明のコモンレールの変形例の断面図Sectional drawing of the modification of the common rail of this invention 従来のコモンレールの斜視図と断面図A perspective view and a sectional view of a conventional common rail
　以下、図面を参照して、本発明のコモンレールに関する実施の形態について具体的に説明する。ただし、かかる実施の形態は本発明の一態様を示すものであり、この発明を限定するものではなく、本発明の範囲内で任意に変更することが可能である。 Hereinafter, embodiments of the common rail according to the present invention will be specifically described with reference to the drawings. However, this embodiment shows one aspect of the present invention, and does not limit the present invention, and can be arbitrarily changed within the scope of the present invention.
　本発明のコモンレール１００について図１を参照して説明する。図１（ａ）は、本発明のコモンレール１００の斜視図が示され、図１（ｂ）は、斜視図に記すＡ－Ａ’線におけるコモンレール本体１１０の軸方向から見た切断面の図（肉厚断面図）が示されている。コモンレール１００は、コモンレール本体１１０と封止部材１２０と縦方向接続部材１３０と横方向接続部材１３１と圧力センサー１４０と圧力制御弁１５０と燃料排出管１６０とにより構成されている。 The common rail 100 of the present invention will be described with reference to FIG. 1A is a perspective view of the common rail 100 of the present invention, and FIG. 1B is a cross-sectional view of the common rail main body 110 taken along the line AA ′ in the perspective view ( (Thickness cross-sectional view) is shown. The common rail 100 includes a common rail main body 110, a sealing member 120, a vertical connection member 130, a horizontal connection member 131, a pressure sensor 140, a pressure control valve 150, and a fuel discharge pipe 160.
　コモンレール本体１１０は高炭素鋼等を素材とする金属製であり、その内部にはコモンレール本体１１０の長手方向に貫通する燃料貯留孔１１１が設けられている。そして、コモンレール本体１１０は燃料貯留孔１１１の両端の開口部を封止部材１２０で閉じることにより内部に円柱状空間を形成し高圧の燃料を貯留可能としている。 The common rail main body 110 is made of a metal made of high carbon steel or the like, and a fuel storage hole 111 penetrating in the longitudinal direction of the common rail main body 110 is provided therein. And the common rail main body 110 forms the cylindrical space inside by closing the opening part of the both ends of the fuel storage hole 111 with the sealing member 120, and can store a high pressure fuel.
　コモンレール本体１１０は、燃料貯留孔１１１の軸方向（図１（ａ）の矢印Ｘが示す方向）から見たときに概ね２方向に分けられる複数の分岐孔がコモンレール本体１１０の燃料貯留孔１１１からコモンレール本体１１０の外部表面に開口するように設けられている。本実施例のコモンレール１００の分岐孔は、図１（ｂ）中において縦方向の分岐孔と横方向の分岐孔に分けられ、縦方向分岐孔１１２が一方の方向に分岐する分岐孔に相当し、横方向分岐孔１１３が他方の方向に分岐する分岐孔に相当する。 The common rail body 110 has a plurality of branch holes divided from the fuel storage holes 111 of the common rail body 110 in two directions when viewed from the axial direction of the fuel storage holes 111 (the direction indicated by the arrow X in FIG. 1A). The common rail body 110 is provided so as to open on the outer surface. In FIG. 1B, the branch holes of the common rail 100 according to the present embodiment are divided into a vertical branch hole and a horizontal branch hole, and the vertical branch hole 112 corresponds to a branch hole that branches in one direction. The lateral branch hole 113 corresponds to a branch hole that branches in the other direction.
　縦方向分岐孔１１２は、コモンレール本体１１０がエンジンに取付けられた時のシール面となるシール面部１１７に直交する角度に配設され、シール面部１１７で開口するように設けられている。縦方向分岐孔１１２は、縦方向接続部材１３０の締結を可能とする拡径された縦方向分岐孔接続部１１２ａを有している。コモンレール本体１１０には縦方向分岐孔１１２が燃料貯留孔１１１の軸線に沿って４箇所並列に設けられ、それぞれに縦方向接続部材１３０がねじ結合によって締結されている。 The longitudinal branch hole 112 is disposed at an angle orthogonal to the seal surface portion 117 that becomes a seal surface when the common rail main body 110 is attached to the engine, and is provided to open at the seal surface portion 117. The longitudinal branch hole 112 has an enlarged longitudinal branch hole connection portion 112 a that enables fastening of the longitudinal connection member 130. The common rail main body 110 is provided with four vertical branch holes 112 in parallel along the axis of the fuel storage hole 111, and a vertical connection member 130 is fastened to each of the common rail main bodies 110 by screw coupling.
　縦方向接続部材１３０は、縦方向分岐孔接続部１１２ａの締結側とは反対側の端部に燃料配管（図示せず）の接続を可能にするねじ部が設けられている。そして、各縦方向接続部材１３０に接続された燃料配管（図示せず）を介してコモンレール１００から各インジェクタ（図示せず）へ高圧の燃料が供給される。 The vertical connection member 130 is provided with a screw portion that enables connection of a fuel pipe (not shown) at the end opposite to the fastening side of the vertical branch hole connection portion 112a. Then, high-pressure fuel is supplied from the common rail 100 to each injector (not shown) via a fuel pipe (not shown) connected to each vertical connection member 130.
　横方向分岐孔１１３は、コモンレール本体１１０の側面に一体的に形成された四つのボス部１１４に開口するように設けられている。縦方向分岐孔１１２と同様に横方向分岐孔１１３も横方向接続部材１３１の締結が可能な横方向分岐孔接続部１１３ａを有し横方向接続部材１３１が取付けられている。コモンレール１００では、横方向接続部材１３１が２箇所の横方向分岐孔接続部１１３ａに締結され、これら２箇所の横方向接続部材１３１に接続された燃料配管（図示せず）を介して燃料供給ポンプ（図示せず）からコモンレール１００内へ高圧の燃料が供給される。 The lateral branch holes 113 are provided so as to open to four boss portions 114 formed integrally on the side surface of the common rail main body 110. Similar to the longitudinal branch hole 112, the lateral branch hole 113 has a lateral branch hole connection portion 113 a to which the lateral connection member 131 can be fastened, and the lateral connection member 131 is attached thereto. In the common rail 100, the lateral connection member 131 is fastened to the two lateral branch hole connection portions 113 a, and the fuel supply pump is connected via a fuel pipe (not shown) connected to the two lateral connection members 131. High-pressure fuel is supplied from the inside (not shown) into the common rail 100.
　また、残りの２箇所の横方向分岐孔１１３の横方向分岐孔接続部１１３ａには、コモンレール１００内の燃料圧力を測定する圧力センサー１４０とコモンレール１００内の燃料圧力を調整するために制御装置（図示せず）によって電子制御される圧力制御弁１５０が締結されている。圧力制御弁１５０が締結されたボス部１１４には、燃料圧力を調整するために排出される燃料の燃料排出管１６０が取付けられている。 Further, the lateral branch hole connecting portions 113a of the remaining two lateral branch holes 113 are provided with a pressure sensor 140 for measuring the fuel pressure in the common rail 100 and a control device (in order to adjust the fuel pressure in the common rail 100). A pressure control valve 150 that is electronically controlled by an unillustrated) is fastened. A fuel discharge pipe 160 for the fuel discharged to adjust the fuel pressure is attached to the boss portion 114 to which the pressure control valve 150 is fastened.
　本実施例のコモンレール１００では、図１（ｂ）の断面図に示されるように、縦方向分岐孔１１２と横方向分岐孔１１３は、それぞれ中心軸がレール本体１１０の同一の肉厚断面上にあると共に燃料貯留孔１１１の径方向で直交する角度に配置されている。 In the common rail 100 of the present embodiment, as shown in the cross-sectional view of FIG. 1B, the longitudinal branch hole 112 and the lateral branch hole 113 are respectively centered on the same thick section of the rail body 110. In addition, the fuel storage holes 111 are arranged at an angle orthogonal to the radial direction.
　次に、本実施例のコモンレール１００の作用及び効果について、図４に示す従来のコモンレール３００と比較して説明する。図２は、分岐孔接続部に接続部材が締結された際に発生する軸力の圧力がコモンレールに加えられたときの燃料貯留孔の変形についてシミュレーションした結果をコモンレール本体の肉厚断面図で模式的に表したものである。図２（ａ）は図１の本実施例のコモンレール１００に対するシミュレーション結果を示し、図２（ｂ）は図４の従来のコモンレール３００に対するシミュレーション結果を示している。 Next, the operation and effect of the common rail 100 of this embodiment will be described in comparison with the conventional common rail 300 shown in FIG. FIG. 2 schematically shows the result of simulating the deformation of the fuel storage hole when the pressure of the axial force generated when the connecting member is fastened to the branch hole connecting portion is applied to the common rail, in the thickness cross-sectional view of the common rail main body. It is a representation. 2A shows a simulation result for the common rail 100 of the present embodiment shown in FIG. 1, and FIG. 2B shows a simulation result for the conventional common rail 300 shown in FIG.
　図２（ｂ）に示す従来のコモンレール３００のコモンレール本体３１０では２方向に分岐する分岐孔３１２，３１３が燃料貯留孔３１１を挟んで上下に対向し、その互いの中心軸が同一直線上にある位置関係となっているため、両分岐孔３１２，３１３の受圧座面３１２ｂ，３１３ｂにかかる軸力の圧力は、白矢印の示す方向の圧力となる。そして、この燃料貯留孔３１１の上下方向からの圧力は、燃料貯留孔３１１を左右方向へ変形させる力となり、燃料貯留孔３１１が点線で示すように変形する。この左右方向への変形により燃料貯留孔３１１の両分岐孔３１２，３１３の開口部周辺に引張り応力が発生する。 In the common rail main body 310 of the conventional common rail 300 shown in FIG. 2B, the branch holes 312 and 313 branching in two directions are vertically opposed to each other with the fuel storage hole 311 interposed therebetween, and their central axes are on the same straight line. Because of the positional relationship, the pressure of the axial force applied to the pressure receiving seat surfaces 312b and 313b of both branch holes 312 and 313 is the pressure indicated by the white arrow. And the pressure from the up-down direction of this fuel storage hole 311 becomes the force which deform | transforms the fuel storage hole 311 to the left-right direction, and the fuel storage hole 311 deform | transforms as shown with a dotted line. Due to the deformation in the left-right direction, tensile stress is generated around the opening portions of both branch holes 312 and 313 of the fuel storage hole 311.
　上述した従来のコモンレールに対し、図２（ａ）に示す本実施例のコモンレール１００の場合、コモンレール本体１１０の分岐孔は、燃料貯留孔１１１の径方向で直交するように配置されているため、両分岐孔１１２，１１３の受圧座面１１２ｂ，１１３ｂにかかる軸力の圧力は、白矢印の示す方向の圧力となる。この圧力は、燃料貯留孔１１１を挟む方向にかかることが無く、また、両分岐孔１１２，１１３の間の広くあいた黒矢印の示す方向へ逃げることから、燃料貯留孔１１１は、従来のコモンレール３００の燃料貯留孔３１１のように左右方向へ大きく変形することがないため、燃料貯留孔１１１の両分岐孔１１２，１１３の開口部周辺の引張り応力の発生を抑えることができる。 In the case of the common rail 100 of the present embodiment shown in FIG. 2A with respect to the above-described conventional common rail, the branch hole of the common rail main body 110 is arranged so as to be orthogonal to the radial direction of the fuel storage hole 111. The pressure of the axial force applied to the pressure receiving seat surfaces 112b and 113b of both the branch holes 112 and 113 is the pressure indicated by the white arrows. This pressure is not applied in the direction in which the fuel storage hole 111 is sandwiched, and escapes in the direction indicated by the wide black arrow between the two branch holes 112 and 113, so that the fuel storage hole 111 is connected to the conventional common rail 300. Since the fuel storage hole 311 is not greatly deformed in the left-right direction, the generation of tensile stress around the opening portions of both the branch holes 112 and 113 of the fuel storage hole 111 can be suppressed.
　次に、図３を参照して図１に示す本発明のコモンレールの変形例について説明する。図３は変形例のコモンレール本体２１０の肉厚断面図を示している。 Next, a modification of the common rail of the present invention shown in FIG. 1 will be described with reference to FIG. FIG. 3 is a cross-sectional view showing a wall thickness of a common rail body 210 according to a modification.
　本発明のコモンレールの変形例において、縦方向分岐孔２１２の分岐孔小径部２１２ｃと横方向分岐孔２１３の分岐孔小径部２１３ｃは、それぞれ分岐孔接続部２１２ａ，２１３ａの中心軸とは異なる中心軸を有している。そして、両分岐孔小径部２１２ｃ、２１３ｃの中心軸は、燃料貯留孔２１１の軸心Ｃに対し偏心した位置に配置されている。 In the modification of the common rail of the present invention, the branch hole small diameter portion 212c of the vertical branch hole 212 and the branch hole small diameter portion 213c of the horizontal branch hole 213 are different from the central axes of the branch hole connection portions 212a and 213a, respectively. have. The central axes of both branch hole small- diameter portions 212 c and 213 c are arranged at positions eccentric from the axis C of the fuel storage hole 211.
　変形例では、分岐孔接続部２１２ａ，２１３ａの中心軸が燃料貯留孔２１１の軸心Ｃに対し偏心することなく設けられ、分岐孔小径部２１２ｃ，２１３ｃの中心軸のみが平行移動する形で燃料貯留孔２１１の軸心Ｃに対し偏心して設けられている。 In the modified example, the center axis of the branch hole connecting portions 212a and 213a is provided without being decentered with respect to the axis C of the fuel storage hole 211, and only the center axis of the branch hole small diameter portions 212c and 213c is translated. The storage hole 211 is provided eccentrically with respect to the axis C.
　分岐孔小径部２１２ｃ，２１３ｃは、図３に示される断面図では偏心によって分岐孔小径部２１２ｃ，２１３ｃと平行する燃料貯留孔２１１の断面円における接線と重なる位置までそれぞれ平行に移動している。 In the cross-sectional view shown in FIG. 3, the branch hole small diameter portions 212 c and 213 c are moved in parallel to each other to a position overlapping with a tangent in the cross-sectional circle of the fuel storage hole 211 parallel to the branch hole small diameter portions 212 c and 213 c due to eccentricity.
両分岐孔小径部２１２ｃ，２１３ｃを上述した位置に配置することで、燃料貯留孔２１１の両分岐孔小径部２１２ｃ，２１３ｃの開口部のエッジ部分は、燃料貯留孔２１１の中心線の位置からそれぞれ外れることになる。これにより、エッジ部分での応力集中は抑えられ左右両方向から引っ張り応力を受ける亀裂の起点が解消される。 By arranging both branch hole small diameter portions 212c and 213c at the positions described above, the edge portions of the opening portions of both branch hole small diameter portions 212c and 213c of the fuel storage hole 211 are respectively located from the position of the center line of the fuel storage hole 211. It will come off. Thereby, the stress concentration at the edge portion is suppressed, and the starting point of the crack receiving the tensile stress from both the left and right directions is eliminated.
　以上説明したように、本発明のコモンレールであれば、分岐孔の配置を適切に行うことにより、燃料貯留孔の分岐孔開口部周辺で発生する引張り応力の低減が可能となり、燃料貯留孔の分岐孔開口部のエッジ部分に発生する亀裂を防止することができる。 As described above, with the common rail of the present invention, by appropriately arranging the branch holes, the tensile stress generated around the branch hole opening of the fuel reservoir hole can be reduced, and the branch of the fuel reservoir hole can be reduced. Cracks generated at the edge portion of the hole opening can be prevented.
　尚、本実施例のコモンレールでは、一方の方向に分岐する分岐孔と他方の方向に分岐する分岐孔をコモンレール本体の同一肉厚断面に位置するようにしているが、これに限るものではなく、例えば、コモンレールの長手方向における他方の方向に分岐する分岐孔の配置は、一方の方向に分岐する分岐孔が長手方向に並んでいる間の位置に配置するようにしても良い。 In the common rail of the present embodiment, the branch hole that branches in one direction and the branch hole that branches in the other direction are positioned on the same thickness cross section of the common rail body, but it is not limited thereto. For example, the arrangement of the branch holes branching in the other direction in the longitudinal direction of the common rail may be arranged at a position while the branch holes branching in one direction are aligned in the longitudinal direction.
　また、本実施例のコモンレールでは、一方の方向に分岐する複数の分岐孔をすべて同じ縦方向に分岐させ、また、他方の方向に分岐する複数の分岐孔もすべて同じ横方向に分岐させているが、必ずしも全く同じ方向に分岐させる必要は無く、レイアウト上の都合に合わせて方向をそれぞれ調整し設けることは可能である。概ね同じ方向であれば、一様の効果は得られる。 Further, in the common rail of this embodiment, a plurality of branch holes that branch in one direction are all branched in the same vertical direction, and a plurality of branch holes that branch in the other direction are also branched in the same lateral direction. However, it is not always necessary to branch in exactly the same direction, and the directions can be adjusted and provided according to the layout. If the directions are substantially the same, a uniform effect can be obtained.
　また、図３の変形例において、分岐孔小径部と分岐孔接続部は、異なる中心軸を持つように構成したが、これに限定するものではなく、分岐孔小径部と分岐孔接続部は、中心軸を同じとしたまま燃料貯留孔の軸心Ｃに対し偏心させても良い。
  Further, in the modification of FIG. 3, the branch hole small diameter part and the branch hole connection part are configured to have different central axes, but the present invention is not limited thereto, and the branch hole small diameter part and the branch hole connection part are You may make it eccentric with respect to the axial center C of a fuel storage hole, making the center axis the same.

Claims (4)

  1. レール本体内部に設けられ高圧の燃料を貯留可能な円柱状空間である燃料貯留孔と、前記燃料貯留孔から前記レール本体外部に向かってそれぞれ分岐する複数の分岐孔とを備えたコモンレールにおいて、
    前記分岐孔は、前記燃料貯留孔の軸方向から見たときに分岐方向が２方向に分けられ、一方の方向に分岐する分岐孔と他方の方向に分岐する分岐孔の中心軸が互いに対向しない角度に配置されていることを特徴とするコモンレール。     In a common rail provided with a fuel storage hole that is a cylindrical space provided inside the rail body and capable of storing high-pressure fuel, and a plurality of branch holes that branch from the fuel storage hole toward the outside of the rail body,
    The branch hole is divided into two directions when viewed from the axial direction of the fuel storage hole, and the center axis of the branch hole that branches in one direction and the branch hole that branches in the other direction do not face each other A common rail characterized by being arranged at an angle.
  2. 　前記一方の方向に分岐する分岐孔と前記他方の方向に分岐する分岐孔の中心軸が、前記コモンレール本体の同一肉厚断面上に一つずつあることを特徴とする請求項１に記載のコモンレール 2. The common rail according to claim 1, wherein one central axis of the branch hole branching in the one direction and one of the branch holes branching in the other direction are provided on the same thickness section of the common rail body.
  3. 　前記一方の方向へ分岐した分岐孔と前記他方の方向へ分岐した分岐孔の中心軸は、前記燃料貯留孔の径方向で直交する角度に配置されていることを特徴とする請求項１～２に記載のコモンレール The central axis of the branch hole branched in the one direction and the branch hole branched in the other direction are arranged at an angle orthogonal to the radial direction of the fuel storage hole. Common rail described in
  4. 前記分岐孔の中心軸が前記燃料貯留孔の軸心に対し偏心した位置にずらされて配置されていることを特徴とする請求項１～３に記載のコモンレール The common rail according to any one of claims 1 to 3, wherein a central axis of the branch hole is shifted to a position eccentric with respect to an axis of the fuel storage hole.
PCT/JP2013/077888 2012-11-16 2013-10-15 Common rail WO2014077072A1 (en)

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