JP2007332955A - High-pressure fuel injection tube having connecting head portion and bend portion, and method for producing the same - Google Patents
High-pressure fuel injection tube having connecting head portion and bend portion, and method for producing the same Download PDFInfo
- Publication number
- JP2007332955A JP2007332955A JP2007061089A JP2007061089A JP2007332955A JP 2007332955 A JP2007332955 A JP 2007332955A JP 2007061089 A JP2007061089 A JP 2007061089A JP 2007061089 A JP2007061089 A JP 2007061089A JP 2007332955 A JP2007332955 A JP 2007332955A
- Authority
- JP
- Japan
- Prior art keywords
- head
- annular flange
- fuel injection
- pressure fuel
- pipe
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000002347 injection Methods 0.000 title claims abstract description 80
- 239000007924 injection Substances 0.000 title claims abstract description 80
- 239000000446 fuel Substances 0.000 title claims abstract description 28
- 238000004519 manufacturing process Methods 0.000 title claims description 12
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 60
- 239000010959 steel Substances 0.000 claims abstract description 60
- 238000010438 heat treatment Methods 0.000 claims abstract description 54
- 230000002093 peripheral effect Effects 0.000 claims abstract description 34
- 230000006698 induction Effects 0.000 claims abstract description 25
- 238000005452 bending Methods 0.000 claims description 55
- 238000000034 method Methods 0.000 claims description 52
- 238000003825 pressing Methods 0.000 claims description 14
- 239000010410 layer Substances 0.000 claims description 10
- 239000002344 surface layer Substances 0.000 claims description 8
- 238000010583 slow cooling Methods 0.000 claims description 7
- 238000003754 machining Methods 0.000 claims description 6
- 239000000463 material Substances 0.000 claims description 5
- 238000002788 crimping Methods 0.000 claims 1
- 230000003763 resistance to breakage Effects 0.000 abstract 1
- 239000000243 solution Substances 0.000 abstract 1
- 238000010791 quenching Methods 0.000 description 13
- 230000000171 quenching effect Effects 0.000 description 12
- 238000000465 moulding Methods 0.000 description 9
- 230000035882 stress Effects 0.000 description 8
- 238000005496 tempering Methods 0.000 description 8
- 239000012530 fluid Substances 0.000 description 7
- 238000012545 processing Methods 0.000 description 7
- 238000000137 annealing Methods 0.000 description 6
- 230000015572 biosynthetic process Effects 0.000 description 6
- 230000013011 mating Effects 0.000 description 6
- 230000003628 erosive effect Effects 0.000 description 5
- 238000001816 cooling Methods 0.000 description 3
- 230000007935 neutral effect Effects 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 230000010349 pulsation Effects 0.000 description 2
- 238000007789 sealing Methods 0.000 description 2
- 239000007921 spray Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 229910000975 Carbon steel Inorganic materials 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000033228 biological regulation Effects 0.000 description 1
- 239000010962 carbon steel Substances 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000013021 overheating Methods 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 239000002436 steel type Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Images
Landscapes
- Fuel-Injection Apparatus (AREA)
Abstract
Description
本発明は、ディーゼル内燃機関のコモンレールによる蓄圧式燃料噴射システム等に使用される高圧用燃料噴射管（以下「噴射管」と略称する。）とその製造方法に関する。 The present invention relates to a high-pressure fuel injection pipe (hereinafter abbreviated as “injection pipe”) used in an accumulator fuel injection system using a common rail of a diesel internal combustion engine, and a method for manufacturing the same.
従来、この種の噴射管としては、図５に例示するように、比較的細径からなる厚肉鋼管２１の接続端部に、球面状のシート面２３と、該シート面２３から軸芯方向に間隔をおいて設けた環状フランジ部２５と、前記シート面２３に連なって前記環状フランジ部２５まで先端に向って先細りとなる円弧面２４とから形成された接続頭部２２を有し、かつ曲げ加工部（屈曲部分）２６を有するものが知られている（特許文献１の図４参照）。この種の接続頭部２２は、外方からのパンチ部材による軸芯方向への押圧による挫屈加工によって成形されるのに関連して、該押圧による挫屈加工に伴う周壁の外側への拡がりによって、該頭部内周面にポケット（環状凹部）２７を生ぜしめて構成され、かかる状態で使用に供されてきたが、ポケット部の形成に伴う内径の大径化とそのポケットの谷部に発生する亀裂により内周面の応力が上昇、並びに配設使用時の高圧流体に起因して該ポケット部付近に発生するキャビテーションエロージョンにより、該接続頭部にポケットを起点に径方向の亀裂が放射状に生じたり、ポケットの周囲に円周方向の亀裂が生じるという問題があった。すなわち、従来の噴射管は、鋼管端末をプレス成形して接続頭部形状としているため、ポケット部周辺の硬さが加工前より１０〜２０％程度アップしていること、また、ポケット内周面の残留応力（歪み）の分布等が要因となってキャビテーションエロージョンの発生状況にばらつきが生じる。そして、この噴射管の硬さ、端末形状によって、ポケット部の亀裂の進展速さによって破壊に差異が生じる。
Conventionally, as an injection pipe of this type, as illustrated in FIG. 5, a
かかる対策として、本出願人は、例えば比較的細径からなる厚肉鋼管の接続端部に、球面状のシート面と、該シート面から軸芯方向に間隔をおいて設けた環状フランジ部と、前記シート面に連なって前記環状フランジ部まで先端に向って先細りとなる円錐面とから形成された接続頭部を有する噴射管において、前記円錐面の一部に深さの浅い環状の湾曲凹溝を設けることによって、該接続頭部の成形に伴って生ずる該頭部内側のポケットを深さが浅くかつなだらかとする方法（特許文献１の図１参照）や、外側周面を相手座部への截頭円錐状、もしくは截頭円弧状のシート面とする接続頭部の成形に伴って生ずる該頭部内側のポケットを、該頭部内側に嵌着する金属製円筒部材で被覆する方法（特許文献２）等を先に提案した。 As such a measure, the present applicant has, for example, a spherical sheet surface at a connection end of a thick steel pipe having a relatively small diameter, and an annular flange portion provided at an interval in the axial direction from the sheet surface. An injection pipe having a connecting head formed from a conical surface that is continuous with the seat surface and tapers toward the tip to the annular flange portion, and a circular curved recess having a shallow depth in a part of the conical surface. By providing a groove, a method of making the pocket inside the head generated along with the formation of the connecting head shallow and gentle (see FIG. 1 of Patent Document 1), or the outer peripheral surface as a mating seat A method of covering a pocket on the inner side of the head generated by forming a connecting head with a frustoconical or frusto-arc shaped sheet surface with a metal cylindrical member fitted inside the head (Patent document 2) etc. were proposed previously.
また、この種の噴射管における曲げ加工部（屈曲部分）については、当該噴射管の耐久性（内圧繰返し強度）に影響を与える管体の偏平現象が問題となる。従来のディーゼルエンジン用噴射管は、外径が６φ、６．３５の場合、内径φ２が主流でφ１．４〜φ２．２（肉厚／外径の比率＝０．３２以上）のものが使用されているため、ＣＮＣベンダー等の曲げ加工手段により曲げ加工を施しても曲げ加工部（屈曲部分）に発生する偏平現象は極めて少なく、また、従来のエンジンの管内圧は直接噴射式燃料噴射システムでも最高１２０ＭＰａ程度である為、前記偏平現象が当該噴射管の耐久性（内圧繰返し強度）に影響を与えることはなく、さらに従来のディーゼルエンジン用噴射管は、コモンレールシステム用噴射管と比べると長さが長いため、曲げＲは大きなＲ（標準曲げＲ：外径×３．０以上）を使用することができた。
ところで、最近のディーゼルエンジンのコモンレールによる蓄圧式燃料噴射システムに使用される噴射管は、排ガス規制等から使用時の圧力が２００ＭＰａ以上に高くなる傾向にあり、このような超高圧に耐えられる内圧疲労強度が要求されている。
従来、噴射管の接続頭部については、前記したごとく、配設使用時の高圧流体に起因して該ポケット部付近に発生するキャビテーションエロージョンによる前記亀裂の発生を防止する手段として、頭部内側のポケットを深さが浅くかつなだらかとする方法や、頭部内側のポケットを金属製円筒部材で被覆する方法等が提案されているが、２００ＭＰａ以上の内圧疲労強度を確保するためには技術的には必ずしも十分とは言えなかった。
By the way, the injection pipes used in recent accumulator fuel injection systems using a common rail of a diesel engine tend to have a pressure during use of 200 MPa or higher due to exhaust gas regulations, etc., and internal pressure fatigue that can withstand such ultra-high pressure Strength is required.
Conventionally, as described above, with respect to the connection head of the injection pipe, as a means for preventing the occurrence of the crack due to cavitation erosion that occurs near the pocket due to the high-pressure fluid at the time of installation and use, A method of making the pocket shallow and gentle, a method of covering the pocket inside the head with a metal cylindrical member, etc. have been proposed, but in order to ensure an internal pressure fatigue strength of 200 MPa or more, it is technically Was not always enough.
また、この燃料噴射システムに使用される噴射管は、以下に記載する理由により、前記した偏平部分の破損の危険性が増大している。
すなわち、最近の蓄圧式燃料噴射システムの高圧仕様に伴い、燃料噴射による脈動が大きくなり、その影響は多数回噴射を行う場合、プレ噴射による圧力変動がメイン噴射時の圧力すなわち噴射量に影響を与える時の弊害が大きいため、この脈動を減少させるためには管内径を大きくする必要が生じ、前記した肉厚／外径の比率が小さくなる傾向にあること、コモンレールシステムの場合は、ポンプとノズルの間にコモンレールが入るために噴射管自体の長さが短くなり、かつ狭い場所（空間）での配管が必要となったことにより、曲げ加工部（屈曲部分）の曲げＲが小さくなり、内径偏平率が１０％を超えるようになったこと、内圧による繰返し疲労に起因する破壊を防止するために噴射管の内表面精度をより高める必要があること（内面疵を小さくすること）等である。
In addition, the injection pipe used in this fuel injection system has an increased risk of breakage of the flat portion described above for the reasons described below.
In other words, with the recent high-pressure specifications of the accumulator fuel injection system, the pulsation caused by fuel injection increases, and the effect of this is that when performing multiple injections, pressure fluctuations due to pre-injection affect the pressure during main injection, that is, the injection amount. In order to reduce this pulsation, it is necessary to increase the inner diameter of the pipe, and the above-mentioned ratio of thickness / outer diameter tends to decrease. Since the common rail enters between the nozzles, the length of the injection pipe itself is shortened, and piping in a narrow place (space) is required, so that the bending R of the bending portion (bending portion) becomes small, The inner diameter flatness has exceeded 10%, and the inner surface accuracy of the injection pipe needs to be increased to prevent breakage caused by repeated fatigue due to internal pressure (inner surface It is the smaller) and the like.
本発明は、従来のこのような現状に鑑みてなされたもので、２００ＭＰａ以上の内圧疲労強度を確保し得る接続頭部と、曲げ加工部における疲労破壊を可及的に防止し得る、コモンレールシステムに使用される接続頭部と曲げ部を有する噴射管およびその製造方法を提案することを目的とするものである。 The present invention has been made in view of the conventional situation as described above, and a common head system capable of ensuring as much as possible an internal pressure fatigue strength of 200 MPa or more and a fatigue failure in a bent portion as much as possible. It is an object of the present invention to propose an injection pipe having a connection head portion and a bending portion, and a manufacturing method thereof.
本発明に係る接続頭部と曲げ部を有する噴射管は、比較的細径からなる厚肉細径鋼管の接続端部に、球面状のシート面と、該シート面から軸芯方向に間隔をおいて形成された環状フランジ部と、前記シート面に連なって前記環状フランジ部まで先端に向かって先細りとなる円錐面を持つ接続頭部を有し、前記環状フランジ部の受圧面と係合する締付ナットを組込んでなる、曲げ部を有する高圧用燃料噴射管において、内径偏平率が６％以下の曲げ部を有し、かつ硬さがＨｖ２８５以上、引張強度が９００ＭＰａ以上であり、かつまた接続頭部のプレスによる挫屈成形前に前記シート面に誘導加熱により軟化させた軟質層を有することを特徴とし、また、前記厚肉細径鋼管がｔ（肉厚）／Ｄ（外径）＜０．３の場合に、接続頭部端末から前記環状フランジ部背面までの軸方向距離Ｌ１が０．３８Ｄ〜０．６Ｄ、前記シート面の球体半径Ｒが０．４５Ｄ〜０．６５Ｄ、前記環状フランジ部外径Ｄ１が１．２Ｄ〜１．４Ｄであって、該頭部内周面が当該鋼管の内周面に近いフラットな面を有する接続頭部を備えたことを特徴とし、また、前記厚肉細径鋼管がｔ（肉厚）／Ｄ（外径）≧０．３の場合に、接続頭部端末から前記環状フランジ部背面までの軸方向距離Ｌ１が０．３８Ｄ〜０．７Ｄ、前記シート面の球体半径Ｒが０．４５Ｄ〜０．６５Ｄ、前記環状フランジ部外径Ｄ１が１．２Ｄ〜１．４Ｄであって、該頭部内周面が当該鋼管の内周面に近いフラットな面を有する接続頭部を備えたことを特徴とし、さらに前記環状フランジ部の首下部にワッシャーを組込んで構成することを好ましい態様とするものである。
また、本発明の接続頭部と曲げ部を有する高圧用燃料噴射管の製造方法は、最終伸管後の厚肉細径鋼管を熱処理工程にて焼入れ・焼戻し処理し伸びが５％以上の管材を得、該管材を規定の製品長さに切断し、次いで該所定長さの厚肉細径鋼管の端部の少なくともシート面形成部位の表面層を誘導加熱により軟化し、さらに予め先端側に接続頭部の加工代を残してチャックに保持した状態で押型を備えたパンチ部材による軸方向先端部外方からのプレスにより挫屈成形して、端部に外側周面を球面となすシート面を有する接続頭部と、該頭部に連なる拡径した環状フランジ部および前記シート面に連なって前記環状フランジ部まで先端に向かって先細りとなる円錐面を形成せしめた後、当該鋼管に曲げ加工を施して内径偏平率が６％以下の曲げ部を形成することを特徴とするものである。
さらに本発明方法は、前記所定長さの厚肉細径鋼管の端部に、予め先端側に接続頭部の加工代を残して短寸筒状のワッシャー部材を組込み、しかる後に端部付近をチャックに保持した状態で挫屈成形し、かつ前記接続頭部の形成に伴って、該直管部分に位置して前記ワッシャー部材を嵌着せしめることを特徴とするものである。
なお、本発明においてシート面の表面層を軟化させる方法として用いる誘導加熱手段としては、高周波誘導加熱方式が好ましい。また、本発明方法は、前記シート面形成部位の加熱による軟化時に、加熱前に予熱および／または加熱後に徐冷することを特徴とし、その際前記予熱および／または徐冷を加熱炉中にて保持または通電による加熱により行うことを好ましい態様とするものである。
An injection pipe having a connection head and a bending portion according to the present invention has a spherical sheet surface at a connection end of a thick thin steel pipe having a relatively small diameter, and an interval in the axial direction from the sheet surface. And a connecting head having a conical surface that is continuous with the seat surface and tapers toward the tip to the annular flange portion, and engages with a pressure receiving surface of the annular flange portion. A high-pressure fuel injection pipe having a bent portion, which is assembled with a tightening nut, has a bent portion with an inner diameter flatness of 6% or less, a hardness of Hv285 or more, a tensile strength of 900 MPa or more, and In addition, the sheet surface has a soft layer softened by induction heating before being crimped by a connecting head press, and the thick thin steel pipe has t (thickness) / D (outer diameter). ) <0.3, the connection head terminal The axial distance L1 to the rear surface of the flange portion is 0.38D to 0.6D, the spherical radius R of the seat surface is 0.45D to 0.65D, and the outer diameter D1 of the annular flange portion is 1.2D to 1.4D. The inner peripheral surface of the head includes a connecting head having a flat surface close to the inner peripheral surface of the steel pipe, and the thick thin steel pipe has t (thickness) / D. When (outer diameter) ≧ 0.3, the axial distance L1 from the connecting head end to the back surface of the annular flange portion is 0.38D to 0.7D, and the spherical radius R of the seat surface is 0.45D to 0. .65D, the annular flange portion outer diameter D1 is 1.2D to 1.4D, and the head inner peripheral surface includes a connecting head having a flat surface close to the inner peripheral surface of the steel pipe. Further, it is preferable that a washer is incorporated in the lower part of the neck of the annular flange portion. It is an aspect had.
The method for producing a high-pressure fuel injection pipe having a connecting head and a bent portion according to the present invention is a pipe material having a elongation of 5% or more by quenching and tempering a thick-walled thin steel pipe after final drawing in a heat treatment process. And cutting the pipe material to a specified product length, and then softening at least the surface layer of the sheet surface forming portion at the end of the thick thin steel pipe having the predetermined length by induction heating, The sheet surface is formed by buckling from the outside of the tip end in the axial direction by a punch member equipped with a pressing die while retaining the machining allowance of the connection head, and the outer peripheral surface is made spherical at the end. A connecting head having a diameter, an enlarged annular flange portion connected to the head portion, and a conical surface tapered toward the tip to the annular flange portion connected to the seat surface, and then bending the steel pipe Bending with an inner diameter flatness of 6% or less It is characterized in that to form the.
Further, according to the method of the present invention, a short cylindrical washer member is incorporated in advance at the end of the thick thin steel pipe having the predetermined length, leaving a machining allowance for the connection head on the tip side, and then the vicinity of the end is formed. It is characterized in that it is bent while being held by a chuck, and the washer member is fitted in the straight pipe portion as the connection head is formed.
In the present invention, the induction heating means used as a method for softening the surface layer of the sheet surface is preferably a high frequency induction heating method. The method of the present invention is characterized in that when the sheet surface forming portion is softened by heating, preheating and / or slow cooling is performed before heating, and in this case, the preheating and / or slow cooling is performed in a heating furnace. It is preferable to perform the heating by holding or energizing.
本発明に係る頭部内周面が当該鋼管の内周面に近いフラットな面を有する接続頭部を設けた噴射管は、硬さがＨｖ２８５以上、引張強度が９００ＭＰａ以上であるから、該頭部成形時におけるポケット部の谷部の亀裂の発生、および該頭部内での流体圧によるキャビテーションエロージョンによる亀裂の発生の憂い、並びに前記頭部成形時における該ポケットの形成に伴う内径の大径化による内表面の引張応力の上昇現象をなくし、かつ該頭部内周面が疲労破壊の起点となる可能性を大幅に減少させることができる上、耐内圧疲労特性のみならず耐振動曲げ疲労特性にも優れる。このため、仮に頭部の内側に小さなポケット（環状凹部）が存在したとしても、エンジン等の噴射圧力の変動により前記ポケット部に亀裂等が発生するおそれはほとんどない。また、少なくともシート面表層に誘導加熱による軟質層が存在するので、相手部材（コモンレール、インジェクター、高圧ポンプ等）の継ぎ手部のシール面（シート面）を塑性変形させることが皆無となり、高いシール性が得られる。さらに、本発明のシート面に形成する軟質層は、複雑な形状をした接続頭部ではなく、単純な円筒状の管端部の誘導加熱により施すので、局部的な過昇温に伴う熱劣化を生じることなく簡単に精度よく接続頭部のシート面の表層に加熱による軟質層を設けることができる。
またさらに、本発明に係る噴射管は、曲げ加工部の偏平率が６％以下と小さいので、当該曲げ部が内周面から疲労破壊することがなく、偏平部分の破損の危険性が大幅に少なくなる。
さらにまた、本発明に係る噴射管の製造方法によれば、最終伸管後の厚肉細径鋼管を熱処理工程にて焼入れ・焼戻し処理を施すことにより、管端末および直管部等が前記熱処理によって残留応力が除去され、かつ強度が高くなるので、接続頭部の形状およびポケットの大きさは適宜選択することができる上、プレス成形においてポケットに有害な亀裂の発生がない形状が選定できる。さらに好ましくは、前記したポケット（環状凹部）がほとんど存在しないように接続頭部を成形することにより、該頭部内周面からの疲労破壊を大幅に減少させることが可能となり、さらに曲げ加工部における疲労破壊を可及的に防止することが可能となるので、２００ＭＰａ以上の内圧疲労強度を有する噴射管を得ることができる。
Since the injection pipe provided with the connecting head having the flat inner surface near the inner peripheral surface of the steel pipe according to the present invention has a hardness of Hv285 or more and a tensile strength of 900 MPa or more, Occurrence of cracks in the valleys of the pockets at the time of molding, and concerns about the occurrence of cracks due to cavitation erosion due to fluid pressure in the head, and the large diameter of the inner diameter accompanying the formation of the pockets at the time of molding the head In addition to eliminating the phenomenon of increase in tensile stress on the inner surface due to the aging, it is possible to greatly reduce the possibility that the inner peripheral surface of the head becomes the starting point of fatigue failure, and not only the resistance to internal pressure fatigue but also vibration bending fatigue resistance Excellent characteristics. For this reason, even if there is a small pocket (annular recess) inside the head, there is almost no possibility that a crack or the like will occur in the pocket due to fluctuations in the injection pressure of the engine or the like. In addition, since a soft layer by induction heating exists at least on the surface of the seat surface, there is no plastic deformation of the seal surface (seat surface) of the joint of the mating member (common rail, injector, high pressure pump, etc.), and high sealing performance Is obtained. Furthermore, since the soft layer formed on the sheet surface of the present invention is applied by induction heating of a simple cylindrical tube end instead of a complicated connection head, thermal deterioration due to local overheating It is possible to easily and accurately provide a soft layer by heating on the surface layer of the sheet surface of the connection head without causing any problems.
Furthermore, since the jet pipe according to the present invention has a flatness ratio of the bent portion as small as 6% or less, the bent portion does not undergo fatigue failure from the inner peripheral surface, and the risk of breakage of the flat portion is greatly increased. Less.
Furthermore, according to the method of manufacturing an injection pipe according to the present invention, a pipe end, a straight pipe part, and the like are subjected to the heat treatment by subjecting the thick thin steel pipe after final drawing to a quenching and tempering treatment in a heat treatment step. Since the residual stress is removed and the strength is increased, the shape of the connecting head and the size of the pocket can be selected as appropriate, and a shape that does not cause harmful cracks in the press molding can be selected. More preferably, by forming the connection head so that the above-described pocket (annular recess) is hardly present, it is possible to greatly reduce fatigue failure from the inner peripheral surface of the head, and further, the bent portion Thus, it is possible to prevent as much as possible fatigue failure in the case of the above, so that an injection tube having an internal pressure fatigue strength of 200 MPa or more can be obtained.
本発明における厚肉細径鋼管の鋼種としては、特に限定するものではないが、高圧配管用炭素鋼鋼管が好適である。また、この厚肉細径鋼管のサイズとしては、管径Ｄが６ｍｍ乃至１０ｍｍ、肉厚ｔが１．２５ｍｍ乃至３．５ｍｍ程度である。 Although it does not specifically limit as a steel type of the thick thin diameter steel pipe in this invention, The carbon steel pipe for high pressure piping is suitable. As for the size of the thick thin steel pipe, the pipe diameter D is 6 mm to 10 mm, and the wall thickness t is about 1.25 mm to 3.5 mm.
本発明において、曲げ部の内径偏平率を６％以下としたのは、６％を超えると偏平部の内周面が疲労破壊を生じる危惧があるためである。また、該噴射管の硬さをＨｖ２８５以上、引張強度を９００ＭＰａ以上としたのは、硬さがＨｖ２８５未満あるいは引張強度が９００ＭＰａ未満では耐内圧疲労性が確保できないためである。さらに、焼入れ・焼戻し処理により伸びが５％以上の管材を得ることとしたのは、その後の曲げ加工を施すのに少なくとも５％以上の伸びを必要とするためである。 In the present invention, the reason why the inner diameter flatness of the bent portion is 6% or less is that if it exceeds 6%, the inner peripheral surface of the flat portion may cause fatigue failure. The reason why the hardness of the spray tube is Hv285 or more and the tensile strength is 900 MPa or more is that internal pressure fatigue resistance cannot be secured if the hardness is less than Hv285 or the tensile strength is less than 900 MPa. Furthermore, the reason why the pipe material having an elongation of 5% or more is obtained by quenching and tempering treatment is that an elongation of at least 5% is required for the subsequent bending process.
また、本発明において、前記厚肉細径鋼管がｔ（肉厚）／Ｄ（外径）＜０．３の場合に、接続頭部端末から前記環状フランジ部背面までの軸方向距離Ｌ１を０．３８Ｄ〜０．６Ｄ、前記シート面の球体半径Ｒを０．４５Ｄ〜０．６５Ｄ、前記環状フランジ部外径Ｄ１を１．２Ｄ〜１．４Ｄとしたのは、以下に記載する理由による。
すなわち、接続頭部端末から前記環状フランジ部２−３背面までの軸方向距離Ｌ１を０．３８Ｄ〜０．６Ｄとしたのは、０．３８Ｄ未満では頭部を形成できず、他方、０．６Ｄを超えると、ポケットが発生するとともに該ポケットが次第に大きくなるためである。また、前記シート面の球体半径Ｒを０．４５Ｄ〜０．６５Ｄとしたのは、０．４５Ｄ未満では頭部を形成できず、他方、０．６５Ｄを超えると、ポケットが発生するとともに該ポケットが次第に大きくなるためである。さらに、前記環状フランジ部外径Ｄ１を１．２Ｄ〜１．４Ｄとしたのは、１．２Ｄ未満では相手部品と締結する際、高い軸力を伝達するめの広い押圧面積か確保できず、他方、１．４Ｄを超えるとポケットが発生するとともに該ポケットが次第に大きくなるためである。
また、前記厚肉細径鋼管がｔ（肉厚）／Ｄ（外径）≧０．３の場合に、接続頭部端末から前記環状フランジ部背面までの軸方向距離Ｌ１を０．３８Ｄ〜０．７Ｄとしたのは、前記と同様、０．３８Ｄ未満では頭部を形成できず、他方、０．７Ｄを超えると、ポケットが発生するとともに該ポケットが次第に大きくなるためである。
In the present invention, when the thick thin steel pipe is t (thickness) / D (outer diameter) <0.3, the axial distance L1 from the connection head end to the rear surface of the annular flange portion is set to 0. .38D to 0.6D, the spherical radius R of the seat surface is set to 0.45D to 0.65D, and the outer diameter D1 of the annular flange portion is set to 1.2D to 1.4D for the reasons described below.
That is, the axial distance L1 from the connecting head terminal to the back surface of the annular flange portion 2-3 is set to 0.38D to 0.6D. If the distance is less than 0.38D, the head cannot be formed. When 6D is exceeded, pockets are generated and the pockets are gradually enlarged. In addition, the sphere radius R of the sheet surface is set to 0.45D to 0.65D because a head cannot be formed if the radius is less than 0.45D, and on the other hand, if the radius exceeds 0.65D, a pocket is generated and the pocket is formed. This is because gradually increases. Furthermore, the reason why the outer diameter D1 of the annular flange portion is set to 1.2D to 1.4D is that if it is less than 1.2D, it is not possible to secure a wide pressing area for transmitting a high axial force when fastening with a mating part. When 1.4D is exceeded, pockets are generated and the pockets are gradually enlarged.
Further, when the thick thin steel pipe is t (thickness) / D (outer diameter) ≧ 0.3, the axial distance L1 from the connecting head end to the back of the annular flange portion is 0.38D-0. .7D is the same as described above because the head cannot be formed if it is less than 0.38D. On the other hand, if it exceeds 0.7D, a pocket is generated and the pocket is gradually enlarged.
最終伸管後に熱処理工程にて行なう厚肉細径鋼管の焼入れ・焼戻しは常法により実施する。具体的には、例えば連続炉またはバッチ炉にて９５０℃の温度に１０分保持後、流体による焼入れを行う方法、または高周波加熱機にて１０５０℃〜１１００℃の温度に５秒保持後、流体による焼入れを行う方法を用いることができる。ここで、流体による焼入れは、ワッシャーやナット等の部品の焼割れを防止するために油による焼入れが望ましい。焼戻しは、例えば６００℃の温度に２０分保持後、徐冷する方法により行うことができる。 Quenching and tempering of thick-walled small-diameter steel pipes performed in the heat treatment process after the final drawing is performed by conventional methods. Specifically, for example, a method of performing quenching with a fluid after holding at a temperature of 950 ° C. for 10 minutes in a continuous furnace or a batch furnace, or a fluid after holding at a temperature of 1050 ° C. to 1100 ° C. for 5 seconds with a high-frequency heater A method of quenching with can be used. Here, quenching with fluid is preferably quenching with oil in order to prevent quench cracking of parts such as washers and nuts. Tempering can be performed by, for example, a method of gradually cooling after holding at a temperature of 600 ° C. for 20 minutes.
また、少なくとも前記シート面に軟質層を設ける方法としては、プレスにより接続頭部を挫屈成形する前に、直管状の厚肉細径鋼管端部の少なくともシート面形成部位を誘導加熱により軟化させる方法を採用する。この方法の場合は、誘導加熱方式により局部的に軟化焼鈍する方法であるも、複雑な形状をした接続頭部ではなく、単純な円筒状の管端部を誘導加熱するため温度管理を適正に行なうことが容易であり、かつ均一に加熱することができるのでシート部に焼鈍むらが発生することもない。なお、上記した誘導加熱方式によるシート面形成部位の軟化焼鈍は７００〜８００℃程度で行なわれることが好ましい。また、軟化焼鈍前に予熱したり軟化焼鈍後に徐冷することによりシート面形成部位の急冷による硬さの軟化不足が妨げられてよい。 Further, as a method of providing at least the soft layer on the sheet surface, at least the sheet surface forming portion of the end portion of the straight tubular thick-walled thin steel pipe is softened by induction heating before the connecting head is buckled by pressing. Adopt the method. In the case of this method, it is a method of softening and annealing locally by induction heating method, but it is not a complicated connection head, but a simple cylindrical tube end is induction heated, so temperature management is appropriate It is easy to carry out and can be uniformly heated, so that unevenness of annealing does not occur in the sheet portion. In addition, it is preferable that softening annealing of the sheet | seat surface formation site | part by the above-mentioned induction heating system is performed at about 700-800 degreeC. Further, preheating before softening annealing or slow cooling after softening annealing may prevent insufficient softening of hardness due to rapid cooling of the sheet surface forming portion.
本発明に係る噴射管の接続頭部の成形方法は、規定の製品長さに切断された厚肉細径鋼管の端部に、誘導加熱によりシート面形成部位を軟化させた後、予め先端側に接続頭部の加工代を残して短寸筒状のワッシャー部材を組込み、しかる後に端部付近をチャックに保持した状態で押型を備えたパンチ部材による軸方向先端部外方からプレス成形して、端部に外側周面を球面となすシート面を有する接続頭部と、該頭部に連なる拡径した環状フランジ部を形成せしめると共に、該形成に伴って、該直管部分に位置して前記ワッシャー部材を圧嵌せしめる方法を用いることができる。
ここで、前記シート面形成部位の加熱による軟化時には、加熱前に予熱および／または加熱後に徐冷することが好ましく、また前記予熱および／または徐冷は加熱炉中にて保持または通電による加熱により行うのが好ましい態様である。
The method for forming the connection head of the injection pipe according to the present invention is such that the sheet surface forming portion is softened by induction heating at the end of the thick thin steel pipe cut to the specified product length, and then the tip side Incorporating a short cylindrical washer member with a machining allowance for the connection head, and then press-molding from the outside of the tip end in the axial direction with a punch member equipped with a pressing die with the vicinity of the end held by the chuck And forming a connecting head having a seat surface whose outer peripheral surface is a spherical surface at the end, and an annular flange portion having an enlarged diameter connected to the head, and being positioned in the straight pipe portion along with the formation. A method of press-fitting the washer member can be used.
Here, when the sheet surface forming portion is softened by heating, preheating and / or slow cooling is preferably performed before heating, and the preheating and / or slow cooling is performed by holding in a heating furnace or heating by energization. This is a preferred embodiment.
噴射管の曲げ加工方法は、特に限定するものではないが、曲げロール、クランプ治具および反力受具等の曲げ加工治具で噴射管を略真円状に保持した状態で曲げ加工を施す方法、前記曲げ加工治具により噴射管を保持した状態で、当該噴射管の曲げ部に相当する部分を曲げ平面に対し偏平部の短軸が垂直な方向になるように偏平させ、その偏平させた状態で曲げ加工を施す方法、噴射管に曲げ加工を施した後その曲げ加工部の偏平部を当該偏平が小さくなるように矯正する方法、前記噴射管の曲げ部に相当する部分を曲げ加工によって生ずる偏平方向とは逆方向に予め押圧偏平化した後、曲げ加工を施す方法、曲げ加工を施した後、該曲げ加工によって生じた偏平部に対し、偏平が小さくなるように当該偏平部の長軸方向から潰し加工を施す方法等を採用することができる。なお、噴射管を曲げ加工する際には、予め管体内に媒体を充填して曲げ加工を施し、曲げ加工後前記媒体を除去する。
前記した曲げ加工方法を実施するための装置としては、例えば上下二分割構造の曲げロール、この曲げロールの周面に噴射管を押圧しながら、この噴射管を介してロール周面上を所定角度回動して当該噴射管を順次曲げ加工する上下二分割構造のクランプ治具および反力受具を有する曲げ手段を備えた装置を用いることができる。
［実施例］
The method for bending the injection tube is not particularly limited, but the bending is performed in a state where the injection tube is held in a substantially circular shape by a bending jig such as a bending roll, a clamp jig, and a reaction force receiver. Method, in a state where the injection tube is held by the bending jig, the portion corresponding to the bending portion of the injection tube is flattened so that the minor axis of the flat portion is perpendicular to the bending plane, and the flattening is performed. Bending the injection tube, bending the injection tube and then correcting the flat portion of the bending portion so that the flatness is reduced, bending the portion corresponding to the bending portion of the injection tube The method of applying a bending process after pre-flattening in a direction opposite to the flat direction generated by the bending process, and after applying the bending process, the flat part of the flat part is reduced so that the flattening is reduced with respect to the flat part generated by the bending process. Crushing from the long axis direction It is possible to adopt the law, and the like. When bending the injection tube, the tube is filled with a medium in advance and subjected to bending, and the medium is removed after bending.
As an apparatus for carrying out the bending method described above, for example, a bending roll having an upper and lower split structure, while pressing the injection pipe against the circumferential surface of the bending roll, a predetermined angle is formed on the circumferential surface of the roll through the injection pipe. It is possible to use an apparatus provided with a bending means having a clamping jig and a reaction force receiver having a vertically split structure that rotates and sequentially bends the injection pipe.
[Example]
図１は本発明に係る噴射管の一実施例を示す平面図、図２は同上噴射管の接続頭部を示す縦断側面図、図３は被加工管である噴射管の曲げ部を平型で押圧して偏平化する方法の一例を示す概略説明図で、（ａ）は押圧前の状態を示す側面図、（ｂ）は同上縦断正面図、図４は噴射管の接続頭部のシート面形成部位を高周波誘導加熱方式により軟化する方法を例示したもので、（ａ）は高周波誘導加熱コイルに厚肉細径鋼管を直接挿入して加熱する方法、（ｂ）は渦巻状電極を厚肉細径鋼管端部に間隔配置し、厚肉細径鋼管を回転させて加熱する方法をそれぞれ示す概略図であり、１は噴射管、２は接続頭部、３曲げ部、４はワッシャー、５は締付ナット、６−１は下型、６−２は上型、７は高周波誘導加熱コイル、８は渦巻状電極である。 FIG. 1 is a plan view showing an embodiment of an injection pipe according to the present invention, FIG. 2 is a longitudinal side view showing a connecting head of the same injection pipe, and FIG. 3 is a plan view showing a bent portion of the injection pipe as a work pipe. It is a schematic explanatory drawing which shows an example of the method of pressing and flattening with (a) is a side view which shows the state before a press, (b) is a vertical front view same as the above, FIG. 4 is a sheet | seat of the connection head part of an injection pipe The method of softening the surface forming part by the high frequency induction heating method is illustrated. (A) is a method of directly inserting a thick thin steel pipe into a high frequency induction heating coil and heating, and (b) is a thick spiral electrode. It is the schematic which shows the method of arrange | positioning space | interval at a thin-walled steel pipe end part, and rotating and heating a thick-walled thin steel pipe, respectively, 1 is an injection pipe, 2 is a connection head, 3 bending parts, 4 is a washer, 5 is a tightening nut, 6-1 is a lower mold, 6-2 is an upper mold, 7 is a high-frequency induction heating coil, and 8 is a spiral electrode.
本発明に係る噴射管１は、厚肉細径鋼管１−１の接続端部に、外側周面を相手座部への球面状のシート面２−１と、該シート面２−１から軸芯方向に間隔をおいて設けた環状フランジ部２−３と、前記シート面２−１に連なって前記環状フランジ部２−３まで先端に向って先細りとなる円錐面２−２とから構成され、かつ頭部内周面が当該鋼管の内周面に近いフラットな面を有する接続頭部２を有している。
この接続頭部は、前記したごとく前記厚肉細径鋼管の外径をＤとした場合に、接続頭部端末から前記環状フランジ部背面までの軸方向距離Ｌ１はｔ／Ｄが０．３未満であれば０．３８Ｄ〜０．６Ｄ、ｔ／Ｄが０．３以上であれば０．３８Ｄ〜０．７Ｄ、前記シート面の球体半径Ｒは０．４５Ｄ〜０．６５Ｄ、前記環状フランジ部外径は１．２Ｄ〜１．４Ｄとなっている。
The
In this connection head, as described above, when the outer diameter of the thick thin steel pipe is D, the axial distance L1 from the connection head end to the back surface of the annular flange portion is less than 0.3 in t / D. 0.38D to 0.6D, 0.38D to 0.7D if t / D is 0.3 or more, the spherical radius R of the seat surface is 0.45D to 0.65D, the annular flange portion The outer diameter is 1.2D to 1.4D.
この噴射管１を製造する方法としては、前記したごとく端末加工前に最終伸管後の厚肉細径鋼管１−１を焼き入れ・焼戻し処理した後、シート面形成部位の表面層を誘導加熱により軟化し、端末加工を施した後に曲げ加工を施す方法がとられる。
すなわち、まず最終伸管後の厚肉細径鋼管１−１を熱処理工程にて焼き入れ・焼戻し処理を施す。具体的には、例えば連続炉またはバッチ炉にて９５０℃の温度に１０分保持後、油または水による焼入れを行う方法、または高周波加熱機にて１０５０℃〜１１００℃の温度に５秒保持後、油または水による焼入れを行う方法等を用いる。また、焼戻しは、例えば６００℃の温度に２０分保持後、徐冷する方法により行う。
熱処理が終了すると、規定の製品長さに切断し、該厚肉細径鋼管１−１のシート面形成部位の表面層を誘導加熱により軟化する。この軟化処理は、例えば図４（ａ）に示すごとく、厚肉細径鋼管１−１のシート面形成部位１−２を高周波誘導加熱コイル７に挿通し、該シート面形成部位１−２を直接加熱して７００〜８００℃程度の温度で行なう方法、または図４（ｂ）に示すごとく、厚肉細径鋼管１−１の接続端部に間隔ｗを有して渦巻状電極８を対向配置し、該渦巻状電極８を固定した状態で厚肉細径鋼管１−１を回転させながら加熱周波数４０ＫＨｚ程度でシート面形成部位１−２を軟化温度（７００〜８００℃程度）に加熱して行う方法を用いることができる。その際、通電もしくは炉中に保持することにより徐冷して加熱後に急冷されることによる硬化を防止したり、あるいは通電もしくは炉中加熱により予熱して加熱後に急冷されることによる硬化を防止することが好ましい。
端末加工は、上記軟化処理後の厚肉細径鋼管１−１の端部に、予め先端側に接続頭部の頭部加工代を残して短寸筒状のワッシャー（スリーブワッシャー）４を組込み、しかる後当該鋼管１−１をチャックに保持した状態で当該鋼管１−１の先端部をパンチ部材により軸芯方向へ押圧する。この押圧により厚肉鋼管１−１の頭部加工代の部分が塑性流動し、厚肉鋼管１−１の先端部に、外側周面を相手座部への球面状のシート面２−１と、該シート面２−１から軸芯方向に間隔をおいて設けた環状フランジ部２−３と、前記シート面に連なって前記環状フランジ部２−３まで先端に向って先細りとなる円錐面２−２とから構成され、かつ頭部内周面が当該鋼管の内周面に近いフラットな面を有する接続頭部２が得られる。この接続頭部２の前記球面状のシート面２−１の表面層には、該頭部成形前に施した前記高周波誘導加熱コイル７による軟化処理により形成された軟質層が存在している。
なお、前記端末加工方法の場合は、成形加工の際、予め先端側に接続頭部の加工代を残してワッシャー部材を組込み、しかる後に端部付近をチャックに保持した状態でプレス成形するので、前記ワッシャー部材は頭部首下部に圧嵌されるが、所定長さの厚肉細径鋼管にワッシャー部材をチャックから離して当該鋼管に遊嵌せしめた状態で前記プレス成形を施して接続頭部を成形し、しかる後に該頭部首下部に前記短寸筒状のワッシャー部材を移動させて嵌着せしめてもよい。
As described above, the
That is, the thick thin steel pipe 1-1 after the final drawing is first quenched and tempered in a heat treatment process. Specifically, for example, after holding at a temperature of 950 ° C. for 10 minutes in a continuous furnace or a batch furnace, quenching with oil or water, or after holding at a temperature of 1050 ° C. to 1100 ° C. for 5 seconds with a high-frequency heater A method of quenching with oil or water is used. Moreover, tempering is performed by the method of hold | maintaining at the temperature of 600 degreeC for 20 minutes, for example, and cooling slowly.
When the heat treatment is completed, the product is cut to a specified product length, and the surface layer of the sheet surface forming portion of the thick thin steel pipe 1-1 is softened by induction heating. For example, as shown in FIG. 4A, the softening process is performed by inserting the sheet surface forming portion 1-2 of the thick thin steel pipe 1-1 into the high-frequency induction heating coil 7, and the sheet surface forming portion 1-2. A method in which heating is performed directly at a temperature of about 700 to 800 ° C., or as shown in FIG. 4B, the
For terminal processing, a short cylindrical washer (sleeve washer) 4 is incorporated in advance at the end of the thick thin steel pipe 1-1 after the softening treatment, leaving the head processing allowance of the connecting head at the tip side. Thereafter, the tip of the steel pipe 1-1 is pressed in the axial direction by the punch member while the steel pipe 1-1 is held by the chuck. By this pressing, the head machining allowance portion of the thick-walled steel pipe 1-1 is plastically flowed, and at the tip of the thick-walled steel pipe 1-1, the outer peripheral surface is a spherical sheet surface 2-1 to the mating seat portion and An annular flange portion 2-3 provided at a distance from the seat surface 2-1 in the axial direction, and a
In the case of the terminal processing method, since the washer member is incorporated in advance at the tip side, leaving the processing cost of the connection head on the tip side, and then press-molded in a state where the end portion is held in the chuck, The washer member is press-fitted to the lower part of the neck of the head, but the press-molding is performed in a state where the washer member is loosely fitted to the steel pipe while being separated from the chuck to a thick thin steel pipe having a predetermined length. After that, the short cylindrical washer member may be moved and fitted to the lower part of the head neck.
前記端末加工後に行なう管の曲げ加工では、前記したごとく噴射管１の曲げ部３の内径偏平率Ｐｒを６％以下とする。この内径偏平率Ｐｒは本願出願人が先に提案した特願２００４−３６２０６８に記載の下記式１で定義される値である。
In the pipe bending performed after the terminal processing, as described above, the inner diameter flatness Pr of the bending portion 3 of the
［式１］
Ｐｒ＝［（ＭａｘｈーＭｉｎｈ）／ ｈ ］×１００（％）
Ｍａｘｈ：曲げ加工後の管の最大内径（ｍｍ）
Ｍｉｎｈ：曲げ加工後の管の最小内径（ｍｍ）
ｈ ：曲げ加工前の管の平均内径（ｍｍ）
[Formula 1]
Pr = [(Maxh−Minh) / h] × 100 (%)
Maxh: Maximum inner diameter of pipe after bending (mm)
Minh: Minimum inner diameter of pipe after bending (mm)
h: Average inner diameter (mm) of the tube before bending
本発明において、噴射管１の曲げ部３の内径偏平率Ｐｒを６％以下としたのは、以下に記載する理由による。
すなわち、燃料噴射管の高圧繰返し試験を行うと、曲げ部３の曲げ平面に垂直な管内（中立軸付近）壁を起点に疲労破壊が発生する。この要因としては、管の曲げ加工により曲げ部は加工硬化されるが、特に中立軸付近では他の部位に比べ変形が少なく硬化が少ないため、疲労限界の向上が乏しく、また、断面が曲げ加工により潰れるため、中立軸付近が応力集中し易い形になることが考えられる。このため、曲げ加工品のＦＥＭ解析を行うと、曲げ部３の内径偏平率Ｐｒが６％を超える７％の潰れ部分では最大４０％アップの応力増加となっていることが判明した。かかる知見より、本発明では曲げ部３の内径偏平率Ｐｒを６％以下と規定した。
In the present invention, the reason why the inner diameter flatness Pr of the bent portion 3 of the
That is, when a high-pressure repeated test of the fuel injection pipe is performed, fatigue failure occurs starting from the inner wall (near the neutral axis) perpendicular to the bending plane of the bending portion 3. The reason for this is that the bent part is work-hardened by bending the tube, but especially in the vicinity of the neutral axis, there is less deformation and less hardening than other parts, so the fatigue limit is poor and the cross-section is bent. Therefore, it can be considered that stress is concentrated in the vicinity of the neutral axis. For this reason, when FEM analysis of the bent product was performed, it was found that the stress increase was up to 40% at the 7% crushed portion where the inner diameter flatness Pr of the bent portion 3 exceeded 6%. From this knowledge, in the present invention, the inner diameter flatness Pr of the bent portion 3 is defined as 6% or less.
また、曲げ加工治具で曲げ加工を施した後、図３に示す装置により被加工管１−１を平型で押圧する場合は、加圧面が平坦面の下型６−１の上面に被加工管１−１を載置し（図ａ）、同じく加圧面が平坦面の上型６−２により被加工管１−１を押圧し偏平させる（図ｂ）。また、この装置による場合は、下型６−１、上型６−２を離間した状態で当該両型を管軸方向に移動させて再度押圧して被加工管１−１を偏平させる方法（型側を移動させる方式）を、あるいは下型６−１、上型６−２を離間した状態で被加工管１−１側を移動させて下型６−１および上型６−２を再度押圧して偏平させる方法（管側を移動させる方式）を採用することもできる。 In addition, after bending with a bending jig, when the processed pipe 1-1 is pressed with a flat mold using the apparatus shown in FIG. 3, the pressing surface is covered on the upper surface of the lower mold 6-1 of the flat surface. The processed tube 1-1 is placed (FIG. A), and the processed tube 1-1 is pressed and flattened by the upper mold 6-2 whose pressure surface is also a flat surface (FIG. B). In the case of this apparatus, the lower mold 6-1 and the upper mold 6-2 are separated from each other, and both molds are moved in the tube axis direction and pressed again to flatten the processed pipe 1-1 ( A method of moving the mold side), or moving the processed pipe 1-1 side with the lower mold 6-1 and the upper mold 6-2 separated from each other to move the lower mold 6-1 and the upper mold 6-2 again. A method of pressing and flattening (a method of moving the tube side) can also be employed.
なお、本発明では、必要に応じてオートフレッテージ処理やヒートソーク（低温焼鈍処理）を行うこともある。 In the present invention, auto-frettage treatment or heat soak (low-temperature annealing treatment) may be performed as necessary.
本発明に係る頭部内周面が当該鋼管の内周面に近いフラットな面を有する接続頭部を設けた高圧用燃料噴射管は、硬さがＨｖ２８５以上、引張強度が９００ＭＰａ以上であるから、該頭部成形時におけるポケット部の谷部の亀裂の発生、および該頭部内での流体圧によるキャビテーションエロージョンによる亀裂の発生の憂い、並びに前記頭部成形時における該ポケットの形成に伴う内径の大径化による内表面の引張応力の上昇現象をなくし、かつ該頭部内周面が疲労破壊の起点となる可能性を大幅に減少させることができる上、耐内圧疲労特性のみならず耐振動曲げ疲労特性にも優れる。このため、仮に頭部の内側に小さなポケット（環状凹部）が存在したとしても、エンジン等の噴射圧力の変動により前記ポケット部に亀裂等が発生するおそれはほとんどない。また、少なくともシート面表層に誘導加熱による軟質層が存在するので、相手部材（コモンレール、インジェクター、高圧ポンプ等）の継ぎ手部のシール面（シート面）を塑性変形させることが皆無となり、高いシール性が得られる。さらに、本発明のシート面に形成する軟質層は、複雑な形状をした接続頭部ではなく、単純な円筒状の管端部の誘導加熱により施すので、簡単に精度よく接続頭部のシート面の表層に加熱による軟質層を設けることができる。
さらに、本発明に係る噴射管は、曲げ加工部の内径偏平率が６％以下と小さいので、当該曲げ部が内周面から疲労破壊することがなく、偏平部分の破損の危険性が大幅に少なくなる。
さらにまた、本発明に係る噴射管の製造方法によれば、最終伸管後の厚肉細径鋼管を熱処理工程にて焼入れ・焼戻し処理を施すことにより、管端末および直管部等が前記熱処理によって残留応力が除去され、かつ強度が高くなるので、接続頭部の形状およびポケットの大きさは適宜選択することができる上、プレス成形においてポケットに有害な亀裂の発生がない形状が選定できる。さらに好ましくは、前記したポケット（環状凹部）がほとんど存在しないように接続頭部を成形することにより、該頭部内周面からの疲労破壊を大幅に減少させることが可能となり、さらに曲げ加工部における疲労破壊を可及的に防止することが可能となるので、２００ＭＰａ以上の内圧疲労強度を有する噴射管を得ることができる。
The fuel injection pipe for high pressure provided with a connecting head having a flat surface in which the inner peripheral surface of the head according to the present invention is close to the inner peripheral surface of the steel pipe has a hardness of Hv285 or more and a tensile strength of 900 MPa or more. , The occurrence of cracks in the valleys of the pockets during the molding of the head, and the concern about the occurrence of cracks due to cavitation erosion due to fluid pressure in the head, and the inner diameter associated with the formation of the pockets during the molding of the heads In addition to eliminating the phenomenon of increase in tensile stress on the inner surface due to the increase in diameter of the inner surface, the possibility that the inner peripheral surface of the head becomes the starting point of fatigue failure can be greatly reduced. Excellent vibration bending fatigue characteristics. For this reason, even if there is a small pocket (annular recess) inside the head, there is almost no possibility that a crack or the like will occur in the pocket due to fluctuations in the injection pressure of the engine or the like. In addition, since a soft layer by induction heating exists at least on the surface of the seat surface, there is no plastic deformation of the seal surface (seat surface) of the joint of the mating member (common rail, injector, high pressure pump, etc.), and high sealing performance Is obtained. Furthermore, since the soft layer formed on the seat surface of the present invention is applied by induction heating at the end of a simple cylindrical tube instead of the connection head having a complicated shape, the seat surface of the connection head can be easily and accurately. A soft layer by heating can be provided on the surface layer.
Furthermore, since the injection tube according to the present invention has an inner diameter flatness of the bent portion as small as 6% or less, the bent portion does not undergo fatigue failure from the inner peripheral surface, and the risk of breakage of the flat portion is greatly increased. Less.
Furthermore, according to the method of manufacturing an injection pipe according to the present invention, a pipe end, a straight pipe part, and the like are subjected to the heat treatment by subjecting the thick thin steel pipe after final drawing to a quenching and tempering treatment in a heat treatment step. Since the residual stress is removed and the strength is increased, the shape of the connecting head and the size of the pocket can be selected as appropriate, and a shape that does not cause harmful cracks in the press molding can be selected. More preferably, by forming the connection head so that the above-described pocket (annular recess) is hardly present, it is possible to greatly reduce fatigue failure from the inner peripheral surface of the head, and further, the bent portion Thus, it is possible to prevent as much as possible fatigue failure in the case of the above, so that an injection tube having an internal pressure fatigue strength of 200 MPa or more can be obtained.
１ 高圧用燃料噴射管
２ 接続頭部
３ 曲げ部
４ ワッシャー
５ 締付ナット
６−１ 下型
６−２ 上型
７ 高周波誘導加熱コイル
８ 渦巻状電極
DESCRIPTION OF
Claims (8)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2007061089A JP4854548B2 (en) | 2006-03-14 | 2007-03-09 | High-pressure fuel injection pipe having a connecting head and a bent portion and method for manufacturing the same |
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2006070048 | 2006-03-14 | ||
| JP2006070048 | 2006-03-14 | ||
| JP2006139621 | 2006-05-18 | ||
| JP2006139621 | 2006-05-18 | ||
| JP2007061089A JP4854548B2 (en) | 2006-03-14 | 2007-03-09 | High-pressure fuel injection pipe having a connecting head and a bent portion and method for manufacturing the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2007332955A true JP2007332955A (en) | 2007-12-27 |
| JP4854548B2 JP4854548B2 (en) | 2012-01-18 |
Family
ID=38932642
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2007061089A Expired - Fee Related JP4854548B2 (en) | 2006-03-14 | 2007-03-09 | High-pressure fuel injection pipe having a connecting head and a bent portion and method for manufacturing the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP4854548B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011099419A (en) * | 2009-11-09 | 2011-05-19 | Otics Corp | Common rail and method of manufacturing the same |
| CN102425519A (en) * | 2011-12-31 | 2012-04-25 | 中国兵器工业集团第七○研究所 | High-pressure fuel oil connecting pipe |
| CN102500668A (en) * | 2011-10-28 | 2012-06-20 | 江苏宏丰奥凯机电有限公司 | High-pressure seamless steel pipe elbow clamp for engine |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01203649A (en) * | 1988-01-21 | 1989-08-16 | Juergen Guido | Fuel injection conduit for internal combustion engine and manufacture thereof |
| JPH0368255U (en) * | 1989-11-06 | 1991-07-04 | ||
| JPH0464793A (en) * | 1990-06-30 | 1992-02-28 | Usui Internatl Ind Co Ltd | Connection structure of branch connection body in high pressure fuel manifold |
| JPH10306757A (en) * | 1997-03-03 | 1998-11-17 | Usui Internatl Ind Co Ltd | Common rail and manufacture thereof |
| JP2002054770A (en) * | 2000-05-29 | 2002-02-20 | Usui Internatl Ind Co Ltd | High pressure metallic pipe having connection head part, method for forming the head part, and connection washer for connection head part |
| JP2003021018A (en) * | 2001-07-09 | 2003-01-24 | Bosch Automotive Systems Corp | Connection device for rail and injection pipe |
| DE10143740A1 (en) * | 2001-09-06 | 2003-04-03 | Siemens Ag | Pressure line connection has corresponding surfaces of ring-nuts, spacing bushes and sealing surface arranged to fix line at angle to turning point |
| JP2004332601A (en) * | 2003-05-06 | 2004-11-25 | Usui Kokusai Sangyo Kaisha Ltd | Common rail with connection joint nut |
-
2007
- 2007-03-09 JP JP2007061089A patent/JP4854548B2/en not_active Expired - Fee Related
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01203649A (en) * | 1988-01-21 | 1989-08-16 | Juergen Guido | Fuel injection conduit for internal combustion engine and manufacture thereof |
| JPH0368255U (en) * | 1989-11-06 | 1991-07-04 | ||
| JPH0464793A (en) * | 1990-06-30 | 1992-02-28 | Usui Internatl Ind Co Ltd | Connection structure of branch connection body in high pressure fuel manifold |
| JPH10306757A (en) * | 1997-03-03 | 1998-11-17 | Usui Internatl Ind Co Ltd | Common rail and manufacture thereof |
| JP2002054770A (en) * | 2000-05-29 | 2002-02-20 | Usui Internatl Ind Co Ltd | High pressure metallic pipe having connection head part, method for forming the head part, and connection washer for connection head part |
| JP2003021018A (en) * | 2001-07-09 | 2003-01-24 | Bosch Automotive Systems Corp | Connection device for rail and injection pipe |
| DE10143740A1 (en) * | 2001-09-06 | 2003-04-03 | Siemens Ag | Pressure line connection has corresponding surfaces of ring-nuts, spacing bushes and sealing surface arranged to fix line at angle to turning point |
| JP2004332601A (en) * | 2003-05-06 | 2004-11-25 | Usui Kokusai Sangyo Kaisha Ltd | Common rail with connection joint nut |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011099419A (en) * | 2009-11-09 | 2011-05-19 | Otics Corp | Common rail and method of manufacturing the same |
| CN102500668A (en) * | 2011-10-28 | 2012-06-20 | 江苏宏丰奥凯机电有限公司 | High-pressure seamless steel pipe elbow clamp for engine |
| CN102425519A (en) * | 2011-12-31 | 2012-04-25 | 中国兵器工业集团第七○研究所 | High-pressure fuel oil connecting pipe |
Also Published As
| Publication number | Publication date |
|---|---|
| JP4854548B2 (en) | 2012-01-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP4849468B2 (en) | High-pressure fuel injection pipe having a connecting head and a bent portion and method for manufacturing the same | |
| KR100290973B1 (en) | High pressure fuel injection tube and its manufacturing method | |
| US4881763A (en) | Fuel injection line with compression nipple formed thereon by upsetting and process for the production thereof | |
| KR100611092B1 (en) | High-pressure fuel pipe for diesel engines | |
| JP4497435B2 (en) | High pressure metal pipe having a connection head, method of forming the head, and sleeve washer for connection head | |
| JP4854548B2 (en) | High-pressure fuel injection pipe having a connecting head and a bent portion and method for manufacturing the same | |
| EP1914418B1 (en) | High-pressure fuel injection accumulator distributor for automobile and method of manufacturing the same | |
| KR940011851B1 (en) | Small thick-walled composite metal tubing and process for producing the same | |
| JP4849469B2 (en) | Method for manufacturing high-pressure fuel injection pipe having connecting head and bent portion | |
| US4261769A (en) | High pressure fuel injection tubing material | |
| JP2002086243A (en) | Hollow rack bar and manufacturing method therefor rack bar | |
| JP5734950B2 (en) | Metal pipe processing method and processing apparatus | |
| JP2002310034A (en) | Common rail for diesel engine | |
| JPH0949025A (en) | Production of uoe steel pipe excellent in collapsing resistance | |
| JP3882960B2 (en) | Manufacturing method of high-pressure fuel injection pipe and high-pressure fuel injection pipe obtained by the method | |
| EP2133553B2 (en) | A process for obtaining a pipe for supplying fuel to an internal combustion engine | |
| CN116412312A (en) | Sleeved coiled tubing repairing device and coiled tubing repairing method based on same | |
| CN101238285B (en) | High pressure fuel injection pressure accumulation distributor for automobile and its manufacturing method | |
| JP2004136369A (en) | Method for producing hollow rack bar, and hollow rack bar | |
| JP4405101B2 (en) | High pressure fuel injection pipe | |
| JP7493737B1 (en) | Manufacturing method of half pipe joint | |
| JPS6238430B2 (en) | ||
| CN109967553A (en) | A kind of forming method of the dome head with extension pipe | |
| JPH10103188A (en) | High pressure fuel injection pipe material and manufacture thereof | |
| JPH0236357B2 (en) |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20100305 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20110531 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20110802 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20110928 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20111025 |
|
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20111025 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20141104 Year of fee payment: 3 |
|
| R150 | Certificate of patent or registration of utility model |
Ref document number: 4854548 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| LAPS | Cancellation because of no payment of annual fees |