JP4027363B2

JP4027363B2 - Fuel injection valve

Info

Publication number: JP4027363B2
Application number: JP2004335428A
Authority: JP
Inventors: 高幸小林; 秀夫加藤
Original assignee: Hitachi Ltd
Current assignee: Hitachi Ltd
Priority date: 2004-11-19
Filing date: 2004-11-19
Publication date: 2007-12-26
Anticipated expiration: 2021-12-27
Also published as: JP2005048776A

Description

本発明は、例えば自動車用エンジン等に燃料を噴射するのに好適に用いられる燃料噴射弁に関する。 The present invention relates to a fuel injection valve suitably used for injecting fuel into, for example, an automobile engine.

一般に、例えば自動車用エンジン等に用いられる燃料噴射弁は、弁ケーシングが磁性金属材料等により筒状に形成され、その内周側には、弁体が変位可能に挿通されている。そして、噴射弁の作動時には、電磁コイルから発生する磁界が弁ケーシングを通じて弁体に作用することにより、該弁体が磁気的に開弁されるものである（例えば、特許文献１参照）。 In general, for example, a fuel injection valve used in an automobile engine or the like has a valve casing formed in a cylindrical shape with a magnetic metal material or the like, and a valve body is inserted in a displaceable manner on the inner peripheral side thereof. When the injection valve is operated, a magnetic field generated from the electromagnetic coil acts on the valve body through the valve casing, so that the valve body is magnetically opened (see, for example, Patent Document 1).

特開２０００−８９９０号公報JP 2000-8990 A

この種の従来技術による燃料噴射弁は、磁性材料により筒状に形成された弁ケーシングとなる筒状体と、該筒状体の一端側に設けられ噴射口を囲んで弁座が形成された弁座部材と、前記筒状体内に変位可能に設けられ一端側が前記弁座部材の弁座に離着座する弁部となり他端側が吸着部となった弁体と、前記筒状体内に圧入して設けられ一端側が該弁体の吸着部に軸方向の隙間を挟んで対向し他端側が前記筒状体内を軸方向の途中位置まで延びるコア筒と、前記筒状体内に設けられ前記弁体を閉弁方向に付勢する付勢ばねと、前記筒状体に設けられ前記弁体の吸着部と前記コア筒との間に磁界を形成することにより前記弁体を付勢ばねに抗して開弁させる電磁アクチュエータとから構成されている。 This type of conventional fuel injection valve has a cylindrical body that is a valve casing formed in a cylindrical shape from a magnetic material, and a valve seat that is provided on one end side of the cylindrical body and surrounds an injection port. A valve seat member, a valve body that is displaceably provided in the cylindrical body and has one end side that is a valve portion that is attached to and detached from the valve seat of the valve seat member and the other end side that is an adsorption portion, and a press-fit into the cylindrical body. One end of the valve body is opposed to the adsorbing portion of the valve body with an axial gap therebetween, and the other end side extends through the cylindrical body to an intermediate position in the axial direction, and the valve body is provided in the cylindrical body. A biasing spring that biases the valve body in a valve closing direction, and a magnetic field is formed between the suction portion of the valve body and the core cylinder, which is provided in the cylindrical body, to resist the biasing spring. And an electromagnetic actuator that opens the valve.

そして、燃料噴射弁の作動時には、筒状体の外周側に設けた電磁アクチュエータの電磁コイルに給電して磁界を形成すると、この磁界は筒状体を通じて弁体の吸着部とコア筒の間に作用する。これにより、弁体はコア筒により磁気的に吸着されて開弁し、筒状体内に供給される燃料が弁座部材の噴射口から外部に噴射されるものである。 When the fuel injection valve is operated, if a magnetic field is formed by supplying power to the electromagnetic coil of the electromagnetic actuator provided on the outer peripheral side of the cylindrical body, this magnetic field passes between the adsorption part of the valve body and the core cylinder through the cylindrical body. Works. As a result, the valve body is magnetically attracted by the core cylinder and opens, and the fuel supplied into the cylindrical body is injected to the outside from the injection port of the valve seat member.

また、噴射弁の組立時には、コア筒の内，外周面に切削加工、研磨加工等の手段により機械加工を施し、大径部と小径部とからなるコア筒を形成する。そして、このように形成したコア筒を筒状体内に仮止め位置まで圧入し、この筒状体の外周側には電磁コイル、磁性カバーを挿嵌した後に、これらの外側に樹脂モールド等の手段によって樹脂カバーを設ける。さらに、前記筒状体の一端側内周（弁体収容部）には弁体、付勢ばねを取付け、その後に弁座部材を挿嵌して溶接し、噴射弁を組立てることができる。 Further, when assembling the injection valve, the inner and outer peripheral surfaces of the core cylinder are machined by means such as cutting and polishing to form a core cylinder composed of a large diameter portion and a small diameter portion. Then, the core cylinder formed in this manner is press-fitted into the cylindrical body to the temporary fixing position, and after inserting an electromagnetic coil and a magnetic cover on the outer peripheral side of the cylindrical body, a means such as a resin mold is provided outside these A resin cover is provided. Furthermore, a valve body and an urging spring can be attached to the inner circumference (valve body housing portion) of the cylindrical body, and then a valve seat member can be inserted and welded to assemble the injection valve.

このとき、前記コア筒と弁体は、前記筒状体内で軸方向の隙間を挟んで対向して配置されているが、この隙間は、弁座部材の溶接時の変化（溶接誤差）等を考慮して予め決められた設定値よりも大きめに形成されている。このため、噴射弁の組立後には、前記コア筒を筒状体内で軸方向に再度圧入（押圧）しながら、前記隙間を予め決められた設定値に調整する調整作業を実施しているものである。 At this time, the core cylinder and the valve body are arranged to face each other with an axial gap interposed in the cylindrical body. This gap causes a change (welding error) or the like during welding of the valve seat member. It is formed larger than a preset value determined in consideration. For this reason, after the injection valve is assembled, an adjustment operation is performed to adjust the gap to a predetermined set value while press-fitting (pressing) the core cylinder in the axial direction again in the cylindrical body. is there.

ところで、上述した従来技術では、筒状体内でコア筒と弁体との隙間調整作業を行うために、前記コア筒を圧入手段で軸方向に押圧しても、このときの残留応力等の影響により前記コア筒が筒状体内で軸方向に、例えば数十μｍ程度の誤差をもって戻ることがある。 By the way, in the above-described prior art, even if the core cylinder is pressed in the axial direction by the press-fitting means in order to perform the clearance adjustment work between the core cylinder and the valve body in the cylindrical body, the influence of residual stress and the like at this time As a result, the core cylinder may return in the axial direction in the cylindrical body with an error of, for example, several tens of μm.

このため、従来技術では、圧入時の残留応力等の影響によって前記弁体の吸着部とコア筒との隙間が僅かに広がり、これによって弁体のストローク量が変化し、燃料噴射量の精度が低下するという問題がある。 For this reason, in the prior art, the gap between the adsorbing portion of the valve body and the core cylinder is slightly widened due to the influence of residual stress at the time of press-fitting, thereby changing the stroke amount of the valve body and improving the accuracy of the fuel injection amount. There is a problem of lowering.

本発明は上述した従来技術の問題に鑑みなされたもので、本発明の目的は、コア筒に汎用的な機械加工処理を施すことにより、弁体のストローク量を安定させ、噴射量の精度を向上できるようにした燃料噴射弁を提供することにある。 The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to stabilize the stroke amount of the valve body and to increase the accuracy of the injection amount by applying a general-purpose machining process to the core tube. An object of the present invention is to provide a fuel injection valve that can be improved.

上述した課題を解決するために、請求項１の発明による燃料噴射弁は、磁性材料により形成され、軸方向の一側が小径な弁体収容部とコア筒挿嵌部となると共に他側が大径な燃料通路部となり、これらのコア筒挿嵌部と燃料通路部との間が段部となった段付きの筒状体と、該筒状体の弁体収容部内に固定して設けられた弁座部材と、軸方向の一側が小径部となると共に他側が大径部となり、前記小径部が前記弁座部材側に位置するように前記大径部が前記筒状体のコア筒挿嵌部内に圧入して固定されたコア筒と、前記筒状体の弁体収容部内で前記コア筒の小径部と前記弁座部材との間に配置された弁体と、前記筒状体の外側に設けられ、前記コア筒と前記弁座部材との間で前記弁体を駆動する電磁アクチュエータとを備え、前記コア筒の大径部の他側端部には、前記筒状体内にコア筒を圧入したときに前記筒状体の段部を越えて前記コア筒挿嵌部の位置まで延びる縮径部を設ける構成としている。To solve the problems described above, the fuel injection valve according to the invention of claim 1 is made form Ri by the magnetic material, the other with one side in the axial direction becomes small diameter valve housing portion and the core tube insertion portion side becomes larger diameter fuel passage portion, a cylindrical body with a stepped became stepped portion between these core tube insertion portion and the fuel passage portion, is fixed to the valve body accommodating portion of the tubular body a valve seat member provided Te, the other side is a large diameter portion with one side in the axial direction becomes small diameter portion, the large diameter portion such that the small diameter portion is located in the valve seat member side of the tubular body a core tube inserting portion core tube which is fixed by press-fitting into a valve body disposed between said valve seat member and the small diameter portion of the core tube in the tubular body valve yield capacity portion of the provided on the outer side of the cylindrical body, and an electromagnetic actuator that drive the said valve body between said valve seat member and the core tube, the large diameter of the core tube Of the other side end portion, Ru and be provided with a reduced diameter portion extending to a position of the core tube inserting portion beyond the stepped portion of the tubular body when press-fitting the core tube into the tubular body Empire.

このように構成することにより、コア筒の大径部には他側端部の外周に、例えば切削加工、研磨加工等の機械的な加工処理手段を用いて縮径部を形成できる。そして、コア筒を筒状体内に圧入して位置決めするときには、コア筒の縮径部と筒状体のコア筒挿嵌部との間にくさび作用を生じさせ、両者の間の摩擦抵抗を縮径部の位置で増大することができる。これによって、コア筒圧入時の残留応力等の影響をなくすことができ、コア筒を筒状体内に圧入するときの位置決め精度を高めることができる。By comprising in this way, a diameter- reduced part can be formed in the outer periphery of an other side edge part in the large diameter part of a core cylinder, for example using mechanical processing means , such as a cutting process and a grinding | polishing process. When the core cylinder is press-fitted into the cylindrical body and positioned, a wedge action is generated between the reduced diameter portion of the core cylinder and the core cylinder insertion portion of the cylindrical body , reducing the frictional resistance therebetween. It can be increased at the position of the diameter. Thereby, the influence of the residual stress at the time of press-fitting the core tube can be eliminated, and the positioning accuracy when press-fitting the core tube into the cylindrical body can be improved.

また、請求項２の発明による燃料噴射弁は、磁性材料により形成され、軸方向の一側が小径な弁体収容部とコア筒挿嵌部となると共に他側が大径な燃料通路部となり、これらのコア筒挿嵌部と燃料通路部との間が段部となった段付きの筒状体と、該筒状体の弁体収容部内に固定して設けられた弁座部材と、軸方向の一側が小径部となると共に他側が大径部となり、前記小径部が前記弁座部材側に位置するように前記大径部が前記筒状体のコア筒挿嵌部内に圧入して固定されたコア筒と、前記筒状体の弁体収容部内で前記コア筒の小径部と前記弁座部材との間に配置された弁体と、前記コア筒の小径部内に固定して設けられたばね受と、該ばね受と前記弁体との間に設けられ前記弁体を閉弁方向に付勢する付勢ばねと、前記筒状体の外側に設けられ、前記コア筒と前記弁座部材との間で前記弁体を前記付勢ばねに抗して駆動する電磁アクチュエータとを備え、前記コア筒の大径部の他側端部には、前記筒状体内にコア筒を圧入したときに前記筒状体の段部を越えて前記コア筒挿嵌部の位置まで延びるテーパ状の面取り部を設ける構成としている。 Further , the fuel injection valve according to the invention of claim 2 is formed of a magnetic material, and one side in the axial direction is a small diameter valve body housing portion and a core tube insertion portion, and the other side is a large diameter fuel passage portion. A stepped tubular body having a step between the core tube insertion portion and the fuel passage portion, a valve seat member fixedly provided in the valve body housing portion of the tubular body, and an axial direction One side is a small diameter portion and the other side is a large diameter portion, and the large diameter portion is press-fitted and fixed in the core tube insertion portion of the cylindrical body so that the small diameter portion is located on the valve seat member side. A core cylinder, a valve element disposed between the small diameter part of the core cylinder and the valve seat member in the valve element housing part of the cylindrical body, and a spring fixedly provided in the small diameter part of the core cylinder and receiving, if the biasing for biasing in the valve closing direction the valve element provided between the valve body and the spring receiver Neto, provided on the outside of the tubular body Is, and an electromagnetic actuator for driving the valve body between the valve seat member and the core barrel against the biasing spring, the other end portion of the large diameter portion of the core barrel, the When the core cylinder is press-fitted into the cylindrical body, a tapered chamfered portion that extends beyond the step portion of the cylindrical body to the position of the core cylinder insertion portion is provided .

また、請求項３の発明によると、前記付勢ばねは、一側が前記弁体内に配置され、他側が前記コア筒の小径部内に配置される構成としている。Further, according to the invention of claim 3, wherein the biasing spring is disposed at one side in the valve body, that has a configuration that the other side is disposed in the small diameter portion of the core tube.

一方、請求項４の発明による燃料噴射弁は、磁性材料により形成され、軸方向の一側が小径な弁体収容部とコア筒挿嵌部となると共に他側が大径な燃料通路部となり、これらのコア筒挿嵌部と燃料通路部との間が段部となった段付きの筒状体と、該筒状体の弁体収容部内に固定して設けられた弁座部材と、軸方向の一側が小径部となると共に他側が大径部となり、前記小径部が前記弁座部材側に位置するように前記大径部が前記筒状体のコア筒挿嵌部内に圧入して固定されたコア筒と、前記筒状体の弁体収容部内で前記コア筒の小径部と前記弁座部材との間に配置された弁体と、前記筒状体の外側に設けられ、前記コア筒と前記弁座部材との間で前記弁体を駆動する電磁アクチュエータとを備え、前記コア筒には、前記大径部の他側端部に縮径部を設け、前記縮径部の端部が前記筒状体の段部を越えて前記コア筒挿嵌部の位置に達するように前記コア筒を前記筒状体内に圧入したときに、前記筒状体のコア筒挿嵌部は、前記縮径部の位置で縮径方向に弾性変形し前記コア筒の位置決めを行う構成としている。On the other hand, the fuel injection valve according to the invention of claim 4 is formed of a magnetic material, and one side in the axial direction is a small diameter valve body housing portion and a core tube insertion portion, and the other side is a large diameter fuel passage portion. A stepped tubular body having a step between the core tube insertion portion and the fuel passage portion, a valve seat member fixedly provided in the valve body housing portion of the tubular body, and an axial direction One side is a small diameter portion and the other side is a large diameter portion, and the large diameter portion is press-fitted and fixed in the core tube insertion portion of the cylindrical body so that the small diameter portion is located on the valve seat member side. A core cylinder, a valve body disposed between the small diameter portion of the core cylinder and the valve seat member in the valve body housing part of the cylindrical body, and provided outside the cylindrical body, the core cylinder and an electromagnetic actuator for driving the valve body between the valve seat member and, in the core barrel, fused to the other end of the large diameter portion The provided parts, the when the end of the reduced diameter portion is press-fitted the core tube to beyond the stepped portion of the tubular body reaches the position of the core tube inserting portion into the tubular body, the tubular core tube insertion portion of the Jo body has a configuration which is located elastically deformed in diameter reduction direction of the reduced diameter portion performs position-decided Me of the core tube.

また、請求項５の発明による燃料噴射弁は、磁性材料により形成され、軸方向の一側が小径な弁体収容部とコア筒挿嵌部となると共に他側が大径な燃料通路部となり、これらのコア筒挿嵌部と燃料通路部との間が段部となった段付きの筒状体と、該筒状体の弁体収容部内に固定して設けられた弁座部材と、軸方向の一側が小径部となると共に他側が大径部となり、前記小径部が前記弁座部材側に位置するように前記大径部が前記筒状体のコア筒挿嵌部内に圧入して固定されたコア筒と、前記筒状体の弁体収容部内で前記コア筒の小径部と前記弁座部材との間に配置された弁体と、前記筒状体の外側に設けられ、前記コア筒と前記弁座部材との間で前記弁体を駆動する電磁アクチュエータとを備え、前記コア筒は、前記筒状体内に圧入したときに前記大径部の他側端部が前記筒状体の段部を越えて前記燃料通路部内へと軸方向に突出し、さらに前記コア筒の大径部の外周には、前記コア筒挿嵌部と接触する位置に環状凹溝を設ける構成としている。 Further, the fuel injection valve according to the invention of claim 5 is formed of a magnetic material, and one side in the axial direction becomes a small diameter valve body accommodating portion and a core tube insertion portion, and the other side becomes a large diameter fuel passage portion. A stepped tubular body having a step between the core tube insertion portion and the fuel passage portion, a valve seat member fixedly provided in the valve body housing portion of the tubular body, and an axial direction One side is a small diameter portion and the other side is a large diameter portion, and the large diameter portion is press-fitted and fixed in the core tube insertion portion of the cylindrical body so that the small diameter portion is located on the valve seat member side. A core cylinder, a valve body disposed between the small diameter portion of the core cylinder and the valve seat member in the valve body housing part of the cylindrical body, and provided outside the cylindrical body, the core cylinder and an electromagnetic actuator for driving the valve body between the valve seat member and said core barrel, when pressed into the tubular body Wherein the outer periphery of the large diameter portion of the large diameter portion of the other end portion protrudes and axially into the fuel passage portion beyond the stepped portion of the tubular body, further wherein the core barrel, the core barrel interpolation fitting portion It is set as the structure which provides an annular ditch | groove in the position which contacts.

上述した通り、請求項１の発明によれば、筒状体内を軸方向に延びるコア筒の大径部には、その他側端部に縮径部を設け、この縮径部は、前記筒状体内にコア筒を圧入したときに筒状体の段部を越えてコア筒挿嵌部の位置まで延びる構成としているので、コア筒を筒状体内に圧入したときに縮径部の位置でアンカー効果（くさび作用）を発生でき、圧入時の残留応力等による影響でコア筒が軸方向に変位するのを前記アンカー効果によって規制することができる。従って、筒状体内でのコア筒の位置決め精度を高めることができ、弁体のストローク量を安定して調整できると共に、燃料噴射量の精度を向上させることができる。As described above, according to the invention of claim 1, the large diameter portion of the core cylinder extending in the axial direction in the cylindrical body is provided with a reduced diameter portion at the other side end portion, and the reduced diameter portion is formed in the cylindrical shape. since a structure that extends to the position of the core tube insertion portion beyond the stepped portion of the tubular body when press-fitting the core tube into the body, at a position of the reduced diameter portion when the press-fitting the core tube into the tubular body An anchor effect (wedge action) can be generated, and displacement of the core tube in the axial direction due to the influence of residual stress or the like during press-fitting can be restricted by the anchor effect. Therefore, the positioning accuracy of the core cylinder in the cylindrical body can be increased, the stroke amount of the valve body can be adjusted stably, and the accuracy of the fuel injection amount can be improved.

また、請求項２に記載の発明によると、コア筒の大径部には、その他側端部にテーパ状の面取り部を設け、該テーパ状の面取り部は、筒状体内にコア筒を圧入したときに前記筒状体の段部を越えてコア筒挿嵌部の位置まで延びる構成としているので、コア筒を筒状体内に圧入して位置決めするときに、前記コア筒と筒状体のコア筒挿嵌部との間に面取り部の位置でアンカー効果を発生でき、両者の間の摩擦抵抗を増大させて圧入時の位置決め精度を高めることができる。 According to the second aspect of the present invention , the large-diameter portion of the core cylinder is provided with a tapered chamfered portion at the other side end , and the tapered chamfered portion press-fits the core cylinder into the cylindrical body. because beyond the stepped portion of the tubular body when being configured to extend to a position of the core tube insertion portion, when the positioning by press-fitting the core tube into the tubular body, the core tube and the cylindrical The anchor effect can be generated at the position of the chamfered portion between the core tube insertion portion of the body , and the frictional resistance between the two can be increased to increase the positioning accuracy during press-fitting.

また、請求項３に記載の発明は、弁体を閉弁方向に付勢する付勢ばねの一側を弁体内に配置することができ、付勢ばねの他側をコア筒の小径部内に配置することができる。 In the invention according to claim 3, one side of the urging spring for urging the valve body in the valve closing direction can be arranged in the valve body, and the other side of the urging spring is placed in the small diameter portion of the core tube. arrangement to can Rukoto.

一方、請求項４に記載の発明によると、コア筒の大径部には、その他側端部に縮径部を設け、該縮径部の端部が筒状体の段部を越えてコア筒挿嵌部の位置に達するように前記コア筒を前記筒状体内に圧入したときに、前記筒状体のコア筒挿嵌部は、前記縮径部の位置で縮径方向に弾性変形し前記コア筒の位置決めを行う構成としているので、コア筒を筒状体内に圧入して位置決めするときには、前記筒状体のコア筒挿嵌部が前記縮径部の位置で縮径方向に弾性変形することにより、筒状体のコア筒挿嵌部とコア筒の縮径部との間にくさび作用を生じさせ、両者の間の摩擦抵抗を縮径部の位置で増大できると共に、筒状体内でのコア筒の位置決め精度を高めることができる。 On the other hand , according to the invention described in claim 4, the large diameter portion of the core cylinder is provided with a reduced diameter portion at the other side end portion, and the end portion of the reduced diameter portion exceeds the step portion of the cylindrical body. when the core barrel to reach the position of the cylindrical insertion portion and press-fitted into the tubular body, the core tube insertion portion of the tubular body, the elastic deformation in the diameter direction at the location of the reduced diameter portion However, since the core cylinder is positioned, when the core cylinder is press-fitted into the cylindrical body and positioned , the core cylinder insertion portion of the cylindrical body is in the reduced diameter direction at the position of the reduced diameter section. in by elastic deformation, causing Maniku rust effect of the reduced diameter portion of the core tube insertion portion and the core tube of the tubular body, the frictional resistance between them can be increased at the location of the reduced diameter portion The positioning accuracy of the core cylinder in the cylindrical body can be improved.

また、請求項５に記載の発明は、コア筒を筒状体内に圧入したときに大径部の他側端部を、筒状体の段部を越えて燃料通路部内へと軸方向に突出させ、前記コア筒の大径部の外周には、コア筒挿嵌部と接触する位置に環状凹溝を設ける構成としているので、コア筒を筒状体内に圧入して位置決めするときに、前記筒状体のコア筒挿嵌部とコア筒との間に環状凹溝の位置でアンカー効果を発生でき、両者の間の摩擦抵抗を増大させて圧入時の位置決め精度を高めることができる。 The invention described in Claim 5, the protruding core tube and another end portion of the large diameter portion when pressed into the tubular body, beyond the stepped portion of the tubular body to the fuel passage portion in the axial direction is, outside circumference of the large diameter portion of the core barrel, since a structure in which Ru an annular groove at a position in contact with the core tube insertion portion, when the positioning by press-fitting the core tube into the tubular body , to increase the possible occurrence of anchor effect at the location of the ring-shaped groove, determined position of the press fitting by increasing the frictional resistance between the two precision between the tubular core tube insertion portion and the core barrel Can do.

以下、本発明の実施の形態による燃料噴射弁を、自動車用エンジンに適用した場合を例に挙げ、添付図面を参照して詳細に説明する。 Hereinafter, a fuel injection valve according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings, taking as an example a case where the fuel injection valve is applied to an automobile engine.

ここで、図１ないし図７は本発明の第１の実施の形態を示している。図中、１は燃料噴射弁の外郭をなす弁ケーシングで、該弁ケーシング１は、後述の筒状体２、磁性カバー１４、樹脂カバー１７等を含んで構成されている。 Here, FIG. 1 to FIG. 7 show a first embodiment of the present invention. In the figure, reference numeral 1 denotes a valve casing that forms the outer shell of the fuel injection valve. The valve casing 1 includes a cylindrical body 2, a magnetic cover 14, a resin cover 17 and the like which will be described later.

２は弁ケーシング１の本体部分を構成する筒状体で、該筒状体２は、例えば電磁ステン
レス鋼等の磁性金属材料により形成された金属パイプ等からなり、図１、図７に示すように段付き筒状体として形成されている。2 is a cylindrical body constituting the main body of the valve casing 1, and the cylindrical body 2 is made of a metal pipe or the like made of a magnetic metal material such as electromagnetic stainless steel, for example, as shown in FIGS. It is formed as a stepped cylindrical body.

そして、筒状体２は、その一端側に位置して後述の弁体８が変位可能に収容される弁体収容部２Ａと、該弁体収容部２Ａの他端側に一体に設けられ、後述のコア筒９が挿嵌されるコア筒挿嵌部２Ｂと、該コア筒挿嵌部２Ｂよりも大径な筒状体としてコア筒挿嵌部２Ｂの他端側に一体に設けられ、弁体収容部２Ａとコア筒挿嵌部２Ｂとに亘って軸方向に延びる燃料通路３が内周側に形成された燃料通路部２Ｃとを含んで構成され、これらはほぼ同軸状に配置されているものである。そして、筒状体２は、図５ないし図７に示すように、小径のコア筒挿嵌部２Ｂと大径の燃料通路部２Ｃとの間が環状の段部２Ｄとなっている。 And the cylindrical body 2 is integrally provided in the other end side of 2 A of valve body accommodating parts which are located in the one end side, and the valve body 8 mentioned later is accommodated so that displacement is possible, A core cylinder insertion portion 2B into which a core cylinder 9 described later is inserted, and a cylindrical body having a larger diameter than the core cylinder insertion portion 2B are integrally provided on the other end side of the core cylinder insertion portion 2B. A fuel passage portion 2C having an axially extending fuel passage 3 extending between the valve body housing portion 2A and the core tube insertion portion 2B is formed on the inner peripheral side, and these are disposed substantially coaxially. It is what. As shown in FIGS. 5 to 7, the cylindrical body 2 has an annular step portion 2 D between the small diameter core tube insertion portion 2 B and the large diameter fuel passage portion 2 C.

また、筒状体２の弁体収容部２Ａとコア筒挿嵌部２Ｂとは、図４に示す如く、例えば０．２〜１０．０ｍｍ程度、好ましくは０．２〜３．０ｍｍ程度の予め定められた径方向寸法（厚さ）ｔを有し、互いにほぼ同径の筒状体として形成されている。また、筒状体２の燃料通路部２Ｃ内には、外部から燃料通路３に供給される燃料を濾過する燃料フィルタ４が、図１に示すように取付けられている。 Further, the valve body accommodating portion 2A and the core tube insertion portion 2B of the cylindrical body 2 are, for example, about 0.2 to 10.0 mm, preferably about 0.2 to 3.0 mm in advance as shown in FIG. They are formed as cylindrical bodies having a predetermined radial dimension (thickness) t and having substantially the same diameter. Further, a fuel filter 4 for filtering fuel supplied from the outside to the fuel passage 3 is mounted in the fuel passage portion 2C of the cylindrical body 2 as shown in FIG.

５は筒状体２の弁体収容部２Ａの一端側内周に挿嵌して設けられた筒状の弁座部材で、該弁座部材５には、図４に示す如く、燃料通路３内の燃料を外部に噴射する噴射口５Ａと、該噴射口５Ａを取囲んで円錐状に形成され、後述する弁体８の弁部８Ｂが離着座する環状の弁座５Ｂとが設けられている。 Reference numeral 5 denotes a cylindrical valve seat member which is provided by being fitted to the inner periphery of one end side of the valve body accommodating portion 2A of the cylindrical body 2. The valve seat member 5 has a fuel passage 3 as shown in FIG. An injection port 5A for injecting the fuel inside to the outside, and an annular valve seat 5B that surrounds the injection port 5A, is formed in a conical shape, and a valve portion 8B of the valve body 8 described later is seated. Yes.

そして、弁座部材５は、筒状体２の弁体収容部２Ａの一端側内周に挿嵌され、その外周側が環状の溶接部６により弁体収容部２Ａと全周に亘って溶接されている。また、弁座部材５の一端側端面には、複数のノズル孔７Ａが穿設されたノズルプレート７が噴射口５Ａを覆う位置に固着されている。 The valve seat member 5 is inserted into the inner circumference of one end side of the valve body housing portion 2A of the cylindrical body 2, and the outer circumferential side thereof is welded over the entire circumference with the valve body housing portion 2A by the annular welded portion 6. ing. In addition, a nozzle plate 7 having a plurality of nozzle holes 7A is fixed to a position where one end side end face of the valve seat member 5 covers the injection port 5A.

８は筒状体２の弁体収容部２Ａ内に変位可能に収容された弁体で、該弁体８は、弁体収容部２Ａ内に軸方向に延設された筒状の弁軸８Ａと、該弁軸８Ａの一端側に固着され、弁座部材５の弁座５Ｂに離着座する球状の弁部８Ｂと、例えば磁性金属材料等を用いて弁軸８Ａの他端側に一体に形成され、弁体収容部２Ａ内に摺動可能に挿嵌された筒状の吸着部８Ｃとによって構成されている。 8 is a valve body accommodated in the valve body accommodating portion 2A of the cylindrical body 2 so as to be displaceable. The valve body 8 is a cylindrical valve shaft 8A extending in the axial direction in the valve body accommodating portion 2A. A spherical valve portion 8B fixed to one end of the valve shaft 8A and seated on the valve seat 5B of the valve seat member 5, and the other end of the valve shaft 8A using, for example, a magnetic metal material. It is formed by a cylindrical suction portion 8C formed and slidably inserted into the valve body housing portion 2A.

そして、弁体８の閉弁時には、その弁部８Ｂが後述する付勢ばね１１のばね力によって弁座部材５の弁座５Ｂに着座した状態に保持され、このとき吸着部８Ｃの他端側端面とコア筒９とは、図４に示す如く、予め調整された寸法をもつ軸方向の隙間Ｓを挟んで対向している。 When the valve body 8 is closed, the valve portion 8B is held in a state of being seated on the valve seat 5B of the valve seat member 5 by a spring force of an urging spring 11 described later, and at this time, the other end side of the adsorption portion 8C. As shown in FIG. 4, the end face and the core cylinder 9 are opposed to each other with an axial gap S having a dimension adjusted in advance.

また、後述の電磁コイル１３に給電したときには、電磁コイル１３により図４中に点線で示す如き磁界Ｈが形成されるため、弁体８の吸着部８Ｃがコア筒９によって磁気的に吸着される。これにより、弁体８は、付勢ばね１１のばね力に抗して隙間Ｓの寸法分だけ軸方向に変位し、図４中の矢示Ａ方向に開弁するものである。 Further, when power is supplied to an electromagnetic coil 13 which will be described later, a magnetic field H as shown by a dotted line in FIG. 4 is formed by the electromagnetic coil 13, so that the attracting portion 8 C of the valve body 8 is magnetically attracted by the core tube 9. . As a result, the valve body 8 is displaced in the axial direction by the dimension of the gap S against the spring force of the biasing spring 11, and opens in the direction indicated by the arrow A in FIG.

９は磁性金属材料等により筒状に形成されたコア部材としてのコア筒で、該コア筒９は、その内，外周面に切削加工、研磨加工等の機械加工を施すことにより、図７に示すように段付筒体として形成され、軸方向一側が小径部９Ａとなり軸方向他側が大径部９Ｂとなっている。そして、コア筒９の重心Ｇは、後述のセンタレス研磨等を容易に行うために大径部９Ｂ側に配置されているものである。 Reference numeral 9 denotes a core cylinder as a core member formed in a cylindrical shape from a magnetic metal material or the like. The core cylinder 9 is subjected to machining such as cutting and polishing on the inner and outer peripheral surfaces thereof, so that FIG. As shown, it is formed as a stepped cylinder, and one side in the axial direction is a small diameter portion 9A and the other side in the axial direction is a large diameter portion 9B. The center of gravity G of the core cylinder 9 is disposed on the large diameter portion 9B side in order to easily perform centerless polishing and the like described later.

また、コア筒９は、筒状体２のコア筒挿嵌部２Ｂ内に圧入手段を用いて挿嵌され、図４に示すように小径部９Ａの端面が吸着部８Ｃの端面と軸方向の隙間Ｓをもって対面する位置でコア筒挿嵌部２Ｂ内に固定されるものである。この場合にコア筒９は、筒状体２のコア筒挿嵌部２Ｂ内に圧入するときに大径部９Ｂの外周側がコア筒挿嵌部２Ｂの内周面に摩擦接触するものである。 Further, the core cylinder 9 is inserted into the core cylinder insertion portion 2B of the cylindrical body 2 by using press-fitting means, and the end surface of the small diameter portion 9A is in the axial direction with the end surface of the suction portion 8C as shown in FIG. It is fixed in the core tube insertion portion 2B at a position facing the gap S. In this case, when the core tube 9 is press-fitted into the core tube insertion portion 2B of the cylindrical body 2, the outer peripheral side of the large diameter portion 9B is in frictional contact with the inner peripheral surface of the core tube insertion portion 2B.

また、コア筒９の大径部９Ｂ側は、筒状体２内を軸方向の途中位置まで延び、大径部９Ｂの端部（他端側）は、図１、図５に示すように筒状体２のコア筒挿嵌部２Ｂから燃料通路部２Ｃ内へと軸方向に突出している。そして、この突出端側となる大径部９Ｂの端部外周面には、後述の切込み部１０が形成されている。 Moreover, the large diameter part 9B side of the core cylinder 9 extends in the cylindrical body 2 to an intermediate position in the axial direction, and the end part (the other end side) of the large diameter part 9B is as shown in FIGS. The cylindrical body 2 protrudes in the axial direction from the core tube insertion portion 2B into the fuel passage portion 2C. And the below-mentioned cut part 10 is formed in the edge part outer peripheral surface of the large diameter part 9B used as this protrusion end side.

１０はコア筒９の大径部９Ｂ側となる他端側外周に設けられた縮径部としての切込み部で、該切込み部１０は、例えば切削加工、研磨加工等の手段を用いて図１、図５に示す如く大径部９Ｂの端部外周に全周にわたり、例えば１００μｍ程度の深さで切込みを入れることにより形成されている。そして、切込み部１０は、コア筒９を筒状体２内に圧入したときにコア筒挿嵌部２Ｂに対するコア筒９の摩擦抵抗を後述の如く増大させ、筒状体２内におけるコア筒９の位置決め精度を高めるものである。 Reference numeral 10 denotes a cut portion as a reduced diameter portion provided on the outer periphery on the other end side which is the large diameter portion 9B side of the core cylinder 9, and the cut portion 10 is shown in FIG. 1 using means such as cutting and polishing. As shown in FIG. 5, the outer periphery of the end of the large-diameter portion 9B is formed over the entire periphery by cutting at a depth of, for example, about 100 μm. The notch 10 increases the frictional resistance of the core tube 9 against the core tube insertion portion 2B when the core tube 9 is press-fitted into the tube 2 as will be described later. This increases the positioning accuracy.

このため、切込み部１０は、図５に示す如くコア筒９の大径部９Ｂ端面から軸方向に所定長さをもって延び、その切込み端１０Ａは、コア筒９の大径部９Ｂが圧入されたコア筒挿嵌部２Ｂの端部に対し寸法Ｌ1 （Ｌ1 ＞０）となる位置まで延在している。即ち、切込み部１０は、図５に示すように筒状体２内にコア筒９を圧入したときに、筒状体２の段部２Ｄを越えてコア筒挿嵌部２Ｂの位置まで寸法Ｌ1 の長さをもって延びている。 Therefore, as shown in FIG. 5, the cut portion 10 extends from the end surface of the large-diameter portion 9B of the core tube 9 with a predetermined length in the axial direction, and the large-diameter portion 9B of the core tube 9 is press-fitted into the cut end 10A. It extends to a position where the dimension L1 (L1> 0) is reached with respect to the end of the core tube insertion portion 2B. That is, the cut saw portion 10, upon press-fitting the core tube 9 into the cylindrical body 2, as shown in FIG. 5, to the position of the core tube insertion portion 2B beyond the step portion 2D of the cylindrical body 2 It extends with a length of dimension L1.

１１は筒状体２内に設けられた付勢ばね、１２はコア筒９の内周側に圧入等の手段を用いて固定された筒状のばね受を示している。そして、付勢ばね１１は、コア筒９の内周側でばね受１２と弁体８との間に圧縮状態で配設され、弁体８を閉弁方向に常時付勢するものである。この場合、付勢ばね１１は、図４に示すように下部側（一側）が弁体８の吸着部８Ｃ内に配置され、上部側（他側）がコア筒９の小径部９Ａ内に配置されている。 Reference numeral 11 denotes an urging spring provided in the cylindrical body 2, and 12 denotes a cylindrical spring support fixed to the inner peripheral side of the core cylinder 9 by means such as press fitting. The urging spring 11 is disposed in a compressed state between the spring receiver 12 and the valve body 8 on the inner peripheral side of the core cylinder 9, and constantly urges the valve body 8 in the valve closing direction. In this case, as shown in FIG. 4, the urging spring 11 has a lower side (one side) disposed in the suction portion 8 C of the valve body 8, and an upper side (the other side) within the small diameter portion 9 A of the core cylinder 9. Has been placed.

１３は筒状体２のコア筒挿嵌部２Ｂの外周側に挿通して設けられた電磁アクチュエータとしての電磁コイルで、該電磁コイル１３は、後述のコネクタ１８を用いて給電されることにより、図４中に点線で示す如き磁界Ｈを発生させる。そして、この磁界Ｈの作用で弁体８の吸着部８Ｃは、コア筒９の小径部９Ａ端面側に磁気的に吸着され、これによって、弁体８は付勢ばね１１のばね力に抗して開弁するものである。 13 is an electromagnetic coil as an electromagnetic actuator provided by being inserted into the outer peripheral side of the core tube insertion portion 2B of the cylindrical body 2, and the electromagnetic coil 13 is fed by using a connector 18 described later, A magnetic field H as shown by a dotted line in FIG. 4 is generated. Then, the attracting portion 8C of the valve body 8 is magnetically attracted to the end surface side of the small diameter portion 9A of the core cylinder 9 by the action of the magnetic field H, whereby the valve body 8 resists the spring force of the urging spring 11. Open the valve.

１４は例えば磁性金属材料等により段付き筒状に形成された磁性カバーで、該磁性カバー１４は、図４に示す如く、筒状体２の弁体収容部２Ａの外周側に環状の溶接部１５を用いて溶接された小径筒部１４Ａと、該小径筒部１４Ａよりも大径の筒状体として小径筒部１４Ａの他端側に一体に形成され、電磁コイル１３を径方向外側から覆う大径筒部１４Ｂとによって構成されている。 Reference numeral 14 denotes a magnetic cover formed in a stepped cylindrical shape by, for example, a magnetic metal material, and the magnetic cover 14 has an annular welded portion on the outer peripheral side of the valve body accommodating portion 2A of the cylindrical body 2 as shown in FIG. 15 is welded with a small diameter cylindrical portion 14 and is formed integrally with the other end of the small diameter cylindrical portion 14A as a cylindrical body having a larger diameter than the small diameter cylindrical portion 14A, and covers the electromagnetic coil 13 from the outside in the radial direction. It is comprised by the large diameter cylinder part 14B.

また、筒状体２のコア筒挿嵌部２Ｂの外周側には、図２に示す如く、例えば磁性金属材料等により略Ｃ字状に形成された連結コア１６が挿嵌され、該連結コア１６は、磁性カバー１４の大径筒部１４Ｂと筒状体２のコア筒挿嵌部２Ｂとの間を磁気的に連結すると共に、磁性カバー１４と協働して電磁コイル１３の外周側に磁路を形成するものである。 Further, as shown in FIG. 2, a connecting core 16 formed in a substantially C shape by a magnetic metal material or the like is inserted into the outer peripheral side of the core tube insertion portion 2B of the cylindrical body 2, and the connecting core 16 is magnetically coupled between the large-diameter cylindrical portion 14B of the magnetic cover 14 and the core cylindrical insertion portion 2B of the cylindrical body 2, and cooperates with the magnetic cover 14 on the outer peripheral side of the electromagnetic coil 13. A magnetic path is formed.

これにより、電磁コイル１３を励磁したときには、図４中に点線で示すように筒状体２の弁体収容部２Ａ、コア筒挿嵌部２Ｂ、弁体８の吸着部８Ｃ、コア筒９、磁性カバー１４および連結コア１６により構成された閉磁路に沿って磁界Ｈが形成され、弁体８の吸着部８Ｃがコア筒９の小径部９Ａ端面側に吸着されるものである。 Thereby, when the electromagnetic coil 13 is excited, as shown by a dotted line in FIG. 4, the valve body housing portion 2A of the cylindrical body 2, the core tube insertion portion 2B, the suction portion 8C of the valve body 8, the core tube 9, A magnetic field H is formed along the closed magnetic path formed by the magnetic cover 14 and the connecting core 16, and the attracting portion 8 C of the valve body 8 is attracted to the end surface side of the small diameter portion 9 A of the core cylinder 9.

一方、１７は例えば樹脂モールド等の手段により筒状体２と磁性カバー１４の他端側を覆うように設けられた樹脂カバーで、該樹脂カバー１７には、図１に示す如く、電磁コイル１３に給電するためのコネクタ１８が設けられている。また、樹脂カバー１７から突出する筒状体２の他端側外周には、例えば燃料配管（図示せず）等との間をシールするシール部材としてのＯリング１９が装着されている。 On the other hand, a resin cover 17 is provided so as to cover the other end of the cylindrical body 2 and the magnetic cover 14 by means such as a resin mold. The resin cover 17 includes an electromagnetic coil 13 as shown in FIG. A connector 18 is provided for supplying power. In addition, an O-ring 19 as a seal member for sealing a space between, for example, a fuel pipe (not shown) and the like is attached to the outer periphery on the other end side of the cylindrical body 2 protruding from the resin cover 17.

２０は例えば樹脂材料等を用いて筒状体２の弁体収容部２Ａに設けられた環状のプロテクタで、該プロテクタ２０は弁体収容部２Ａから径方向外向きに突出している。また、２１は筒状体２の一端側外周に装着されたＯリングで、このＯリング２１は、磁性カバー１４とプロテクタ２０との間に抜止め状態で配置され、例えば筒状体２の一端側をエンジンの吸気管に設けられたボス部（図示せず）等に嵌合したときに、これらの間をシールするものである。 Reference numeral 20 denotes an annular protector provided in the valve body housing portion 2A of the cylindrical body 2 using, for example, a resin material, and the protector 20 projects radially outward from the valve body housing portion 2A. Reference numeral 21 denotes an O-ring attached to the outer periphery of one end of the cylindrical body 2, and this O-ring 21 is disposed between the magnetic cover 14 and the protector 20 in a retaining state, for example, one end of the cylindrical body 2. When the side is fitted to a boss (not shown) or the like provided in the intake pipe of the engine, the gap between them is sealed.

本実施の形態による燃料噴射弁は上述の如き構成を有するもので、次にその作動について説明する。 The fuel injection valve according to the present embodiment has the above-described configuration, and the operation thereof will be described next.

まず、燃料噴射弁の組立てる前に、コア筒９の内，外周面には切削加工、研磨加工等の機械加工を施し、例えば図７に示す如くコア筒９に小径部９Ａと大径部９Ｂとを形成する。そして、大径部９Ｂの端部外周側には全周にわたって縮径部となる切込み部１０を形成する。 First, before the fuel injection valve is assembled, the inner and outer peripheral surfaces of the core tube 9 are subjected to machining such as cutting and polishing, and the core tube 9 has a small diameter portion 9A and a large diameter portion 9B as shown in FIG. And form. And the notch part 10 which becomes a reduced diameter part over the perimeter is formed in the edge part outer peripheral side of the large diameter part 9B.

次に、このように形成したコア筒９を筒状体２のコア筒挿嵌部２Ｂ内に圧入して設け、前記筒状体２の外周側には電磁コイル１３、磁性カバー１４を挿嵌した後に、これらの外側に樹脂モールド等の手段によって樹脂カバー１７を設ける。また、筒状体２の弁体収容部２Ａ内には、弁体８、付勢ばね１１等を取付け、さらに弁座部材５を挿嵌して溶接し、噴射弁を組立てることができる。 Next, the core cylinder 9 thus formed is press-fitted into the core cylinder insertion portion 2B of the cylindrical body 2, and the electromagnetic coil 13 and the magnetic cover 14 are inserted into the outer peripheral side of the cylindrical body 2. After that, the resin cover 17 is provided on the outside by means such as a resin mold. In addition, the valve body 8, the urging spring 11 and the like are attached in the valve body housing portion 2A of the cylindrical body 2, and the valve seat member 5 is inserted and welded to assemble the injection valve.

また、噴射弁を自動車用エンジン等に実装したときには、筒状体２の他端側にＯリング１９等を介して接続される燃料配管等から筒状体２の燃料通路３内に燃料が供給される。そして、コネクタ１８により電磁コイル１３に給電すると、図４に示す如く磁界Ｈが形成され、この磁界Ｈは弁体８の吸着部８Ｃとコア筒９との間を通過するようになる。 When the injection valve is mounted on an automobile engine or the like, fuel is supplied into the fuel passage 3 of the cylindrical body 2 from a fuel pipe or the like connected to the other end of the cylindrical body 2 via an O-ring 19 or the like. Is done. Then, when power is supplied to the electromagnetic coil 13 by the connector 18, a magnetic field H is formed as shown in FIG. 4, and this magnetic field H passes between the adsorption portion 8 C of the valve body 8 and the core tube 9.

このため、弁体８はコア筒９によって磁気的に吸着され、付勢ばね１１に抗して軸方向に変位すると共に、その弁部８Ｂが弁座部材５の弁座５Ｂから離座して開弁する。これにより、燃料通路３内の燃料は噴射口５Ａからエンジンの吸気管等に向けて噴射される。 For this reason, the valve body 8 is magnetically attracted by the core tube 9 and is displaced in the axial direction against the biasing spring 11, and the valve portion 8B is separated from the valve seat 5B of the valve seat member 5. Open the valve. Thereby, the fuel in the fuel passage 3 is injected from the injection port 5A toward the intake pipe of the engine.

ところで、上述の如く組立てられる燃料噴射弁は、弁座部材５を筒状体２の弁体収容部２Ａ内に溶接するときの溶接誤差等を考慮して、弁体８とコア筒９との間の軸方向の隙間Ｓを予め決められた設定値よりも大きめに確保しておき、噴射弁の組立後にはコア筒９を筒状体２のコア筒挿嵌部２Ｂ内で軸方向に再度圧入（押圧）しながら、前記隙間Ｓを予め決められた設定値に調整する調整作業を実施している。 By the way, in the fuel injection valve assembled as described above, the welding between the valve body 8 and the core cylinder 9 is considered in consideration of welding errors when the valve seat member 5 is welded into the valve body housing portion 2A of the tubular body 2. The axial gap S between them is ensured to be larger than a predetermined set value, and after the injection valve is assembled, the core cylinder 9 is again axially relocated within the core cylinder insertion portion 2B of the cylindrical body 2. Adjustment work is performed to adjust the gap S to a predetermined set value while press-fitting (pressing).

しかし、このような隙間調整作業を行うときには、コア筒９を圧入手段で軸方向に押圧しても、このときの残留応力等の影響によりコア筒９が筒状体２のコア筒挿嵌部２Ｂ内で軸方向に、例えば数十μｍ程度の誤差をもって戻ることがある。そして、このために弁体８の吸着部８Ｃとコア筒９との隙間Ｓが僅かでも広がると、弁体８のストローク量が変化することになり、燃料噴射量の制御を高精度に行うことが難しくなる。 However, when performing such clearance adjustment work, even if the core cylinder 9 is pressed in the axial direction by the press-fitting means, the core cylinder 9 is inserted into the core cylinder insertion portion of the cylindrical body 2 due to the influence of residual stress or the like at this time. 2B may return in the axial direction with an error of, for example, several tens of μm. For this reason, if the gap S between the adsorbing portion 8C of the valve body 8 and the core tube 9 increases even slightly, the stroke amount of the valve body 8 changes, and the fuel injection amount is controlled with high accuracy. Becomes difficult.

そこで、本実施の形態にあっては、コア筒９の他端側となる大径部９Ｂの端部外周側に全周にわたった切込み部１０を形成し、この切込み部１０は、図５に示すように筒状体２内にコア筒９を圧入したときに、筒状体２の段部２Ｄを越えてコア筒挿嵌部２Ｂの位置まで寸法Ｌ1 の長さをもって延びる構成としている。これにより、筒状体２のコア筒挿嵌部２Ｂ内にコア筒９を圧入したときの摩擦抵抗を、切込み部１０によって増大させ、筒状体２内でのコア筒９の位置決め精度を高めることができるようにしている。Therefore, in the present embodiment, the notch 10 extending over the entire circumference is formed on the outer periphery of the end of the large-diameter portion 9B, which is the other end of the core tube 9, and the notch 10 is shown in FIG. when press-fitting the core tube 9 into the cylindrical body 2, as shown in, and the past extends with a length position until in dimension L1 of the core tube insertion portion 2B to configure the step portion 2D of the cylindrical body 2 . Thereby, the frictional resistance when the core cylinder 9 is press-fitted into the core cylinder insertion part 2B of the cylindrical body 2 is increased by the notch 10 and the positioning accuracy of the core cylinder 9 in the cylindrical body 2 is increased. To be able to.

即ち、コア筒９の大径部９Ｂは、筒状体２のコア筒挿嵌部２Ｂ内に圧入するときにコア筒挿嵌部２Ｂの内周面に摩擦接触するように、大径部９Ｂの外周面には高精度な研磨加工を施している。そして、コア筒９の大径部９Ｂを筒状体２のコア筒挿嵌部２Ｂ内に圧入したときには、図６に例示するようにコア筒９の大径部９Ｂから筒状体２に対して矢示Ｂ方向の拡径力が働き、筒状体２からコア筒９の大径部９Ｂに対しては矢示Ｃ方向の縮径力が働くことになる。 That is, the large-diameter portion 9B of the core cylinder 9 is configured so that the large-diameter portion 9B is in frictional contact with the inner peripheral surface of the core cylinder insertion portion 2B when press-fitted into the core cylinder insertion portion 2B of the cylindrical body 2. High-precision polishing is applied to the outer peripheral surface. And when the large diameter part 9B of the core cylinder 9 is press-fitted into the core cylinder insertion part 2B of the cylindrical body 2, the large diameter part 9B of the core cylinder 9 is connected to the cylindrical body 2 as illustrated in FIG. Thus, a diameter expansion force in the direction indicated by the arrow B acts, and a diameter reducing force in the direction indicated by the arrow C acts from the cylindrical body 2 to the large diameter portion 9B of the core cylinder 9.

そして、このような矢示Ｂ方向の拡径力と矢示Ｃ方向の縮径力とは、コア筒９の大径部９Ｂ外周面側では互いに釣合った状態に保たれるが、切込み部１０の位置ではコア筒挿嵌部２Ｂに矢示Ｃ方向の縮径力のみが働くことになり、切込み部１０の切込み端１０Ａ側ではコア筒挿嵌部２Ｂの一部が図６中に仮想線で示すように弾性変形し、矢示Ｄ方向のくさび力を発生する。 Further, the diameter expansion force in the direction indicated by the arrow B and the diameter reduction force in the direction indicated by the arrow C are kept in balance with each other on the outer peripheral surface side of the large diameter portion 9B of the core tube 9. At position 10, only the diameter reducing force in the direction indicated by the arrow C acts on the core tube insertion portion 2B. On the cut end 10A side of the cut portion 10, a part of the core tube insertion portion 2B is virtually shown in FIG. As indicated by the line, it is elastically deformed to generate a wedge force in the direction indicated by arrow D.

この結果、コア筒９の大径部９Ｂには、切込み部１０の切込み端１０Ａ側で矢示Ｄ方向のくさび力によりアンカー効果（くさび作用）が働き、筒状体２とコア筒９との間の摩擦抵抗を増大することができる。また、このときにコア筒挿嵌部２Ｂの一部は、切込み部１０の切込み端１０Ａ側で矢示Ｄ方向のくさび力により僅かにひっかかるように弾性変形し、コア筒９が残留応力等による影響で図６中の矢示Ｅ方向に戻ろうとするのを、前記アンカー効果によって規制することができる。 As a result, the anchor effect (wedge action) acts on the large-diameter portion 9B of the core tube 9 by the wedge force in the direction indicated by the arrow D on the cut end 10A side of the cut portion 10, and the cylindrical body 2 and the core tube 9 The frictional resistance between them can be increased. At this time, a part of the core tube insertion portion 2B is elastically deformed so as to be slightly caught by the wedge force in the arrow D direction on the cut end 10A side of the cut portion 10, and the core tube 9 is caused by residual stress or the like. It is possible to regulate the effect of returning to the direction of arrow E in FIG.

これにより、筒状体２内でのコア筒９の位置決め精度を高め、弁体８とコア筒９との間の軸方向の隙間Ｓを予め決められた設定値に隙間調整することができる。そして、噴射弁の作動時には、電磁コイル１３による磁界Ｈが弁体８とコア筒９との間の隙間Ｓを通り、弁体８を調整されたストローク量（隙間Ｓ）により開弁させることができ、安定した燃料噴射量の制御を確保できる。 Thereby, the positioning accuracy of the core cylinder 9 in the cylindrical body 2 can be improved, and the axial clearance S between the valve body 8 and the core cylinder 9 can be adjusted to a predetermined set value. When the injection valve is operated, the magnetic field H generated by the electromagnetic coil 13 passes through the gap S between the valve body 8 and the core tube 9, and the valve body 8 can be opened by the adjusted stroke amount (gap S). And stable control of the fuel injection amount can be ensured.

従って、本実施の形態によれば、コア筒９の他端側となる大径部９Ｂの端部外周側に汎用的な機械加工処理を施して全周にわたる切込み部１０を形成することにより、弁体８のストローク量を一定に設定することができ、燃料噴射量の精度を確実に向上できる。 Therefore, according to the present embodiment, by performing a general-purpose machining process on the outer peripheral side of the end of the large-diameter portion 9B that is the other end side of the core cylinder 9, the cut portion 10 is formed over the entire circumference. The stroke amount of the valve body 8 can be set constant, and the accuracy of the fuel injection amount can be reliably improved.

また、コア筒９の重心を大径部９Ｂ側に配置する構成としているので、前述の如くコア筒９の大径部９Ｂ外周に研磨加工を施すときに、専用の支え治具等を予め特別に製作して用意しておく必要がなくなり、加工が容易なセンターレス研磨を採用することができ、これによって仕上げ加工等を効率的に行うことができる。 Further, since the center of gravity of the core tube 9 is arranged on the large diameter portion 9B side, a special support jig or the like is specially provided in advance when polishing the outer periphery of the large diameter portion 9B of the core tube 9 as described above. Therefore, centerless polishing that is easy to process can be employed, and finishing and the like can be performed efficiently.

次に、図８は本発明の第２の実施の形態を示し、本実施の形態では前述した第１の実施の形態と同一の構成要素に同一の符号を付し、その説明を省略するものとする。しかし、本実施の形態の特徴は、コア筒３１の他端側外周に縮径部としての面取り部３２を形成したことにある。 Next, FIG. 8 shows a second embodiment of the present invention. In this embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and description thereof is omitted. And However, the feature of the present embodiment is that a chamfered portion 32 as a reduced diameter portion is formed on the outer periphery of the other end side of the core tube 31.

ここで、コア筒３１は、第１の実施の形態で述べたコア筒９と同様に構成され、小径部３１Ａと大径部３１Ｂとを有している。また、縮径部となる面取り部３２は、大径部３１Ｂの端部外周側にテーパ状の面取りを全周にわたって施すことにより形成されている。そして、面取り部３２は、筒状体２のコア筒挿嵌部２Ｂの端部に対し寸法Ｌ2 （Ｌ2 ＞０）となる位置まで延在しているものである。即ち、テーパ状の面取り部３２は、図８に示すように筒状体２内にコア筒３１を圧入したときに、筒状体２の段部２Ｄを越えてコア筒挿嵌部２Ｂの位置まで寸法Ｌ2 の長さをもって延びている。 Here, the core cylinder 31 is configured similarly to the core cylinder 9 described in the first embodiment, and includes a small diameter portion 31A and a large diameter portion 31B. Further, the chamfered portion 32 serving as a reduced diameter portion is formed by applying a tapered chamfer to the outer peripheral side of the end portion of the large diameter portion 31B over the entire circumference. The chamfered portion 32 extends to a position where the dimension L2 (L2> 0) is satisfied with respect to the end of the core tube fitting portion 2B of the cylindrical body 2. That is, the tapered chamfered portion 32, upon press-fitting the core tube 31 in the cylindrical body 2, as shown in FIG. 8, the position of the core tube inserted fitting portion 2B beyond the step portion 2D of the cylindrical body 2 Extends with a length of dimension L2.

かくして、このように構成される本実施の形態でも、前記第１の実施の形態とほぼ同様の作用効果を得ることができる。特に本実施の形態では、コア筒３１の端部外周側に面取り加工を施すだけで面取り部３２を形成でき、機械加工をさらに容易に行うことができる。 Thus, in the present embodiment configured as described above, it is possible to obtain substantially the same operational effects as those of the first embodiment. In particular, in the present embodiment, the chamfered portion 32 can be formed simply by chamfering the outer peripheral side of the end portion of the core cylinder 31, and machining can be performed more easily.

次に、図９は本発明の第３の実施の形態を示し、本実施の形態では前述した第１の実施の形態と同一の構成要素に同一の符号を付し、その説明を省略するものとする。しかし、本実施の形態の特徴は、コア筒４１の他端側外周に環状凹溝４２を複数個形成したことにある。Next, FIG. 9 shows a third embodiment of the present invention. In this embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and description thereof is omitted. And However, features of the present embodiment is a ring-shaped groove 42 on the other end side outer periphery of the core tube 41 to the plural number.

ここで、コア筒４１は、第１の実施の形態で述べたコア筒９と同様に構成され、小径部４１Ａと大径部４１Ｂとを有している。また、複数の環状凹溝４２，４２，…は、大径部４１Ｂの外周側のうち筒状体２のコア筒挿嵌部２Ｂと摩擦接触する位置に互いに軸方向に離間して形成されている。そして、各環状凹溝４２は、横断面がコ字形状をなす環状溝（例えば溝幅が１００μｍ程度、溝深さが１００μｍ程度）により形成されている。この場合、大径部４１Ｂの上側（他側）端部は、図９示す如くコア筒４１を筒状体２内に圧入したときに、筒状体２の段部２Ｄを越えて燃料通路部２Ｃ内へと軸方向に突出し、複数の環状凹溝４２，４２，…は、大径部４１Ｂの外周に軸方向に互いに離間して設けられている。 Here, the core cylinder 41 is configured similarly to the core cylinder 9 described in the first embodiment, and includes a small diameter portion 41A and a large diameter portion 41B. The annular groove 42, 42 of multiple, ... are formed apart from each other in the axial direction in a position to contact friction with the outer peripheral side of the inner cylindrical member 2 of the core tube insertion portion 2B of the large diameter portion 41B ing. Each annular groove 42 is formed by an annular groove having a U-shaped cross section (for example, a groove width of about 100 μm and a groove depth of about 100 μm). In this case, the upper (the other side) end portion of the large-diameter portion 41B, upon press-fitting the core tube 41 as shown FIG. 9 in the cylindrical body 2, the fuel beyond the step portion 2D of the cylindrical body 2 protrudes into the passage portion 2C in the axial direction, a plurality of ring-shaped grooves 42, 42, ... are provided apart from each other in the axial direction on the outer periphery of the large-diameter portion 41B.

かくして、このように構成される本実施の形態でも、前記第１の実施の形態とほぼ同様の作用効果を得ることができる。特に本実施の形態では、コア筒４１の大径部４１Ｂ外周側に複数の環状凹溝４２を形成したので、これらの各環状凹溝４２によりアンカー効果（くさび作用）を生じさせ、筒状体２内でのコア筒４１の位置決め精度を確実に向上することができる。 Thus, in the present embodiment configured as described above, it is possible to obtain substantially the same operational effects as those of the first embodiment. In particular, in the present embodiment, since the plurality of annular grooves 42 are formed on the outer peripheral side of the large-diameter portion 41B of the core cylinder 41, an anchor effect (wedge action) is generated by each of these annular grooves 42, and the cylindrical body The positioning accuracy of the core cylinder 41 within 2 can be reliably improved.

なお、前記第３の実施の形態では、コア筒４１の大径部４１Ｂ外周側に複数の環状凹溝４２を設けるものとして説明した。しかし、本発明はこれに限らず、例えば１個の環状凹溝を設ける構成としてもよい。また、環状凹溝は、必ずしも断面コ字形状に形成する必要はなく、例えば断面半円形状、断面Ｕ字状または断面Ｖ字状をなす凹溝として形成してもよい。 In the third embodiment, a case has been described in which a plurality of annular grooves 42 are provided on the outer peripheral side of the large-diameter portion 41B of the core cylinder 41. However, the present invention is not limited to this, and for example, one annular groove may be provided. The annular groove is not necessarily formed in a U-shaped cross section, and may be formed as a groove having a semicircular cross section, a U-shaped cross section, or a V-shaped cross section, for example.

本発明の第１の実施の形態による燃料噴射弁を示す縦断面図である。It is a longitudinal section showing a fuel injection valve by a 1st embodiment of the present invention. 図１中の矢示II−II方向からみた燃料噴射弁の拡大断面図である。It is an expanded sectional view of the fuel injection valve seen from the arrow II-II direction in FIG. 図１中の矢示III−III方向からみた燃料噴射弁の拡大断面図である。It is an expanded sectional view of the fuel injection valve seen from the arrow III-III direction in FIG. 燃料噴射弁の弁体側を拡大して示す図１の要部拡大断面図である。It is a principal part expanded sectional view of FIG. 1 which expands and shows the valve body side of a fuel injection valve. コア筒の大径部側を拡大して示す図１の要部拡大断面図である。It is a principal part expanded sectional view of FIG. 1 which expands and shows the large diameter part side of a core cylinder. 図５中の切込み部近傍を拡大して示す断面図である。It is sectional drawing which expands and shows the notch part vicinity in FIG. 図１中の筒状体、弁座部材、弁体、コア筒、電磁コイル、磁性カバーおよび連結コアを組立てる前の状態で示す縦断面図である。It is a longitudinal cross-sectional view shown in the state before assembling the cylindrical body in FIG. 1, a valve seat member, a valve body, a core cylinder, an electromagnetic coil, a magnetic cover, and a connection core. 第２の実施の形態による燃料噴射弁のコア筒等を拡大して示す図５とほぼ同様位置での断面図である。FIG. 6 is a cross-sectional view at substantially the same position as in FIG. 5 showing an enlarged view of a core cylinder and the like of a fuel injection valve according to a second embodiment. 第３の実施の形態による燃料噴射弁のコア筒等を拡大して示す図５とほぼ同様位置での断面図である。It is sectional drawing in the substantially the same position as FIG. 5 which expands and shows the core cylinder etc. of the fuel injection valve by 3rd Embodiment.

Explanation of symbols

１弁ケーシング
２筒状体
２Ａ弁体収容部
２Ｂコア筒挿嵌部
２Ｃ燃料通路部
２Ｄ段部
５弁座部材
５Ａ噴射口
５Ｂ弁座
８弁体
８Ａ弁軸
８Ｂ弁部
８Ｃ吸着部
９，３１，４１コア筒
９Ａ，３１Ａ，４１Ａ小径部
９Ｂ，３１Ｂ，４１Ｂ大径部
１０切込み部（縮径部）
１１付勢ばね
１３電磁コイル（電磁アクチュエータ）
１４磁性カバー
１６連結コア
１７樹脂カバー
３２面取り部（縮径部）
４２環状凹溝DESCRIPTION OF SYMBOLS 1 Valve casing 2 Tubular body 2A Valve body accommodating part 2B Core cylinder insertion part
2C fuel passage
2D step portion 5 Valve seat member 5A Injection port 5B Valve seat 8 Valve body 8A Valve shaft 8B Valve portion 8C Adsorption portion 9, 31, 41 Core cylinder 9A, 31A, 41A Small diameter portion 9B, 31B, 41B Large diameter portion 10 Cut portion (Reduced diameter part)
11 Biasing spring 13 Electromagnetic coil (electromagnetic actuator)
14 Magnetic cover 16 Connecting core 17 Resin cover 32 Chamfered portion (reduced diameter portion)
42 Annular groove

Claims

Made Rikatachi by the magnetic material, the other side is a large-diameter fuel passage portion co the one side in the axial direction becomes small diameter valve housing portion and the core tube insertion portion, these core tube insertion portion and the fuel passage a cylindrical body with a stepped was Tsu Do a stepped portion between the parts,
A valve seat member provided fixedly to the valve body accommodating portion of said tubular body,
One side in the axial direction becomes a small diameter portion and the other side becomes a large diameter portion, and the large diameter portion is press-fitted into the core tube insertion portion of the cylindrical body so that the small diameter portion is located on the valve seat member side. A fixed core cylinder ,
A valve element disposed between the valve seat member and the small diameter portion of the core barrel in the valve body accommodating portion of the tubular body,
Is provided outside the front Symbol cylindrical body, and an electromagnetic actuator that drive the said valve body between said valve seat member and the core tube,
The other diameter end of the large-diameter portion of the core cylinder has a reduced diameter portion that extends to the position of the core cylinder insertion portion over the step of the cylindrical body when the core cylinder is press-fitted into the cylindrical body. fuel injection valves ing be provided with a.

Is formed of a magnetic material, one side of the axial direction other side is a large-diameter fuel passage portion to co If a smaller diameter valve body accommodating portion and the core tube inserting portion, and these core tube insertion portion and the fuel passage portion during the cylindrical body stepped was Tsu Do the stepped portion,
A valve seat member fixed in the valve body housing portion of the tubular body;
One side in the axial direction becomes a small diameter portion and the other side becomes a large diameter portion, and the large diameter portion is press-fitted into the core tube insertion portion of the cylindrical body so that the small diameter portion is located on the valve seat member side. A fixed core cylinder ,
A valve body disposed between the small diameter part of the core cylinder and the valve seat member in the valve body housing part of the cylindrical body;
A spring receiver fixedly provided in the small diameter portion of the core tube;
A biasing spring that is provided between the spring receiver and the valve body and biases the valve body in a valve closing direction;
An electromagnetic actuator provided on the outside of the cylindrical body, and driving the valve body against the biasing spring between the core cylinder and the valve seat member ;
The other end portion of the large-diameter portion of the core tube has a tapered shape that extends to the position of the core tube insertion portion beyond the step portion of the tubular body when the core tube is press-fitted into the tubular body. a fuel injection valve comprising a structure provided with a chamfer.

Wherein the biasing spring is one side disposed in said valve body, the other side of the fuel injection valve according to claim 2 comprising a structure disposed within the small diameter portion of the core tube.

Is formed of a magnetic material, one side of the axial direction other side is a large-diameter fuel passage portion to co If a smaller diameter valve body accommodating portion and the core tube inserting portion, and these core tube insertion portion and the fuel passage portion during the cylindrical body stepped was Tsu Do the stepped portion,
A valve seat member fixed in the valve body housing portion of the tubular body;
One side in the axial direction becomes a small diameter portion and the other side becomes a large diameter portion, and the large diameter portion is press-fitted into the core tube insertion portion of the cylindrical body so that the small diameter portion is located on the valve seat member side. A fixed core cylinder ,
A valve body disposed between the small diameter part of the core cylinder and the valve seat member in the valve body housing part of the cylindrical body;
An electromagnetic actuator provided on the outside of the cylindrical body, and driving the valve body between the core cylinder and the valve seat member ;
The core tube is provided with a reduced diameter portion at the other end of the large diameter portion,
When the core cylinder is press-fitted into the cylindrical body so that the end of the reduced diameter portion passes the step of the cylindrical body and reaches the position of the core cylinder insertion portion, the core of the cylindrical body The cylinder insertion portion is a fuel injection valve configured to elastically deform in the diameter reducing direction at the position of the diameter reducing portion and position the core cylinder .

Is formed of a magnetic material, one side of the axial direction other side is a large-diameter fuel passage portion to co If a smaller diameter valve body accommodating portion and the core tube inserting portion, and these core tube insertion portion and the fuel passage portion during the cylindrical body stepped was Tsu Do the stepped portion,
A valve seat member fixed in the valve body housing portion of the tubular body;
One side in the axial direction becomes a small diameter portion and the other side becomes a large diameter portion, and the large diameter portion is press-fitted into the core tube insertion portion of the cylindrical body so that the small diameter portion is located on the valve seat member side. A fixed core cylinder ,
A valve body disposed between the small diameter part of the core cylinder and the valve seat member in the valve body housing part of the cylindrical body;
An electromagnetic actuator provided on the outside of the cylindrical body, and driving the valve body between the core cylinder and the valve seat member ;
When the core cylinder is press-fitted into the cylindrical body, the other end of the large diameter portion protrudes axially into the fuel passage section beyond the step of the cylindrical body ,
Furthermore, the fuel injection valve which becomes a structure which provides an annular recessed groove in the outer periphery of the large diameter part of the said core cylinder in the position which contacts the said core cylinder insertion part .