JP2024024512A - electromagnetic fuel injection valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic fuel injection valve in which, when a coil is energized, a movable core is always adsorbed to a stationary core in an appropriate attitude with no inclination without being affected by an inclination of a valve body, and when energization of the coil is cut off, the movable core is caused to abut against a valve closing side stopper while suppressing the bouncing.

SOLUTION: When a first annular gap set between a valve body 40 and a pair of guide parts 46a and 46b is represented as G1, a second annular gap set between a valve housing 9 and a movable core 41 is represented as G2, and a third annular gap set between the movable core 41 and the valve body 40 is represented as G3, G1<G2<G3 and (G1+G2)<G3 are satisfied. The movable core 41 is slidably supported only by an inner peripheral surface of the valve housing 9, and a valve closing side stopper 49 is fitted to the inner peripheral surface of the valve housing 9, and fixed while an annular abutment part 50 that continues into an outer periphery of the movable core is provided at a front end surface of the movable core 41 so as to abut against a rear end surface of the valve closing side stopper 49 when a coil 32 is not energized.

SELECTED DRAWING: Figure 2

COPYRIGHT: (C)2024,JPO&INPIT

Description

本発明は，主として内燃機関の燃料供給系に使用される電磁式燃料噴射弁に関し，特に，前端部に弁座を有する弁ハウジングと，該弁ハウジングの後端に連設される中空の固定コアと，該固定コアの外周に配設されるコイルと，前記弁座と協働する弁部にロッドが連設されてなる弁体と，前記固定コアの前端面に対向しながら前記弁ハウジング内に摺動可能に配設され，中心部には，前記ロッドに貫通される通孔を有する可動コアと，前記ロッドに固定されると共に前記固定コアの中空部に摺動可能に配設され，前記コイルの通電時，前記固定コアに吸引される前記可動コアにより押動されて前記弁体を開弁作動させる開弁側ストッパと，前記可動コアの前端面に対向して配設される閉弁側ストッパと，前記弁体を閉弁方向に付勢する弁ばねと，前記コイルの非通電時，前記弁体の閉弁を許容すべく，前記可動コアを前記開弁側ストッパから離反させて前記閉弁側ストッパに当接させるように付勢する補助ばねとを備える電磁式燃料噴射弁の改良に関する。 The present invention relates to an electromagnetic fuel injection valve mainly used in a fuel supply system of an internal combustion engine, and in particular, to a valve housing having a valve seat at the front end, and a hollow fixed core connected to the rear end of the valve housing. a coil disposed around the outer periphery of the fixed core; a valve element having a rod connected to a valve portion that cooperates with the valve seat; a movable core having a through hole penetrated by the rod in the center; a movable core fixed to the rod and slidably disposed in a hollow part of the fixed core; When the coil is energized, the valve-opening side stopper is pushed by the movable core attracted by the fixed core to open the valve body, and the valve-opening stopper is disposed opposite to the front end surface of the movable core. a valve-side stopper; a valve spring that urges the valve body in a valve-closing direction; and a valve spring that moves the movable core away from the valve-opening side stopper to allow the valve body to close when the coil is not energized. The present invention relates to an improvement in an electromagnetic fuel injection valve including an auxiliary spring that urges the valve to contact the valve-closing stopper.

かかる電磁式燃料噴射弁は，下記特許文献１に開示されるように既に知られている。 Such an electromagnetic fuel injection valve is already known as disclosed in Patent Document 1 below.

特許第６７８８０８５号公報Patent No. 6788085

特許文献１記載の電磁式燃料噴射弁では，可動コアの摺動を弁体のロッドによりガイドすべく，可動コア及びロッド間の環状間隙を，可動コア及び弁ハウジング間の環状間隙よりも小さく設定しているので，弁体に傾きが生じた場合には，その影響を受けて可動コアも傾くことになる。可動コアのこのような傾きは，コイルの通電時，可動コアの固定コアへの適正な吸着状態に遅れを生じさせ，弁体の開弁を遅らせることになる。また，閉弁側ストッパは，前記ロッドに嵌合して固定され，コイルの通電遮断時，可動コアの内周寄りで，その前端面を支承するようになっているので，可動コアは，閉弁側ストッパへの当接時，傾いてバウンシングを生起させ易い。そのバウンシングが，次のコイル通電時までに収束しない場合には，燃料噴射特性に悪影響を及ぼすことになる。 In the electromagnetic fuel injection valve described in Patent Document 1, the annular gap between the movable core and the rod is set smaller than the annular gap between the movable core and the valve housing so that the sliding movement of the movable core is guided by the rod of the valve body. Therefore, if the valve body tilts, the movable core will also tilt due to the influence. Such an inclination of the movable core causes a delay in proper adsorption of the movable core to the fixed core when the coil is energized, and delays opening of the valve body. In addition, the valve closing side stopper is fixed by fitting into the rod, and supports the front end surface of the movable core near the inner circumference when the coil is de-energized, so that the movable core is closed. When it comes into contact with the valve side stopper, it tends to tilt and cause bouncing. If the bouncing does not converge by the time the coil is energized next, it will adversely affect the fuel injection characteristics.

本発明はかかる事情に鑑みてなされたもので，コイルの通電時には，可動コアを，弁体の傾きに影響されず，常に傾きのない適正姿勢をもって可動コアに吸着させ，またコイルの通電遮断時には，可動コアを，そのバウンシングを抑制しながら閉弁側ストッパに当接させ得る前記電磁式燃料噴射弁を提供することを目的とする。 The present invention has been made in view of the above circumstances, and when the coil is energized, the movable core is not affected by the inclination of the valve body and is always attracted to the movable core in a proper posture with no inclination, and when the coil is de-energized, It is an object of the present invention to provide the electromagnetic fuel injection valve that allows the movable core to come into contact with the valve-closing stopper while suppressing bouncing of the movable core.

上記目的を達成するために，本発明は，前端部に弁座を有する弁ハウジングと，該弁ハウジングの後端に連設される中空の固定コアと，該固定コアの外周に配設されるコイルと，前記弁座と協働する弁部にロッドが連設されてなる弁体と，前記固定コアの前端面に対向しながら前記弁ハウジング内に摺動可能に配設され，中心部には，前記ロッドに貫通される通孔を有する可動コアと，前記ロッドに固定されると共に前記固定コアの中空部に摺動可能に配設され，前記コイルの通電時，前記固定コアに吸引される前記可動コアにより押動されて前記弁体を開弁作動させる開弁側ストッパと，前記可動コアの前端面に対向して配設される閉弁側ストッパと，前記弁体を閉弁方向に付勢する弁ばねと，前記コイルの非通電時，前記可動コアを前記開弁側ストッパから離反させて前記閉弁側ストッパに当接させるように付勢して，前記弁体の閉弁を許容する補助ばねとを備え，更に前記弁体の開閉動作をガイドすべく，前記可動コアを挟んで弁体の軸方向に並ぶ一対のガイド部を備える電磁式燃料噴射弁であって，
前記弁体と前記一対のガイド部との間に設定される第１環状間隙をＧ１，前記弁ハウジングと可動コアとの間に設定される第２環状間隙をＧ２，可動コアと前記ロッドとの間に設定される第３環状間隙をＧ３としたとき，
Ｇ１＜Ｇ２＜Ｇ３・・・・・・（１）
（Ｇ１＋Ｇ２）＜Ｇ３・・・・（２）
上記２式を満足させて，前記可動コアを前記弁ハウジングの内周面のみで摺動自在に支持し，前記閉弁側ストッパを前記弁ハウジングの内周面に嵌合，固定する一方，前記可動コアの前端面には，その外周に連なる環状当接部を，前記コイルの非通電時に前記閉弁側ストッパの後端面に当接可能に設けることを第１の特徴とする。 In order to achieve the above object, the present invention provides a valve housing having a valve seat at the front end, a hollow fixed core connected to the rear end of the valve housing, and a hollow fixed core arranged around the outer periphery of the fixed core. A coil, a valve element having a rod connected to a valve part that cooperates with the valve seat, and a valve body that is slidably disposed within the valve housing while facing the front end surface of the fixed core, and is located in the center of the valve body. has a movable core having a through hole penetrated by the rod, and is fixed to the rod and slidably disposed in a hollow part of the fixed core, and is attracted to the fixed core when the coil is energized. a valve-opening stopper that is pushed by the movable core to open the valve body; a valve-closing stopper that is disposed opposite to the front end surface of the movable core; and a valve spring that biases the movable core to move away from the valve-opening side stopper and come into contact with the valve-closing side stopper when the coil is de-energized, thereby closing the valve body. The electromagnetic fuel injection valve is provided with an auxiliary spring that allows the valve body to open and close, and further includes a pair of guide portions aligned in the axial direction of the valve body with the movable core sandwiched therebetween to guide opening and closing operations of the valve body,
G1 is the first annular gap set between the valve body and the pair of guide parts, G2 is the second annular gap between the valve housing and the movable core, and G2 is the gap between the movable core and the rod. When the third annular gap set in between is G3,
G1<G2<G3...(1)
(G1+G2)<G3...(2)
The above two equations are satisfied, the movable core is slidably supported only on the inner circumferential surface of the valve housing, and the valve closing side stopper is fitted and fixed to the inner circumferential surface of the valve housing. A first feature is that the movable core has an annular abutting portion on the front end surface of the movable core, which is continuous with the outer periphery of the movable core, and is capable of coming into contact with the rear end surface of the valve-closing stopper when the coil is not energized.

また，本発明は，第１の特徴に加えて，前記可動コアの前端面には，前記環状当接部の内周に連なるテーパ状の凹部を設けることを第２の特徴とする。 In addition to the first feature, the present invention has a second feature in that the front end surface of the movable core is provided with a tapered recess that extends to the inner periphery of the annular contact portion.

本発明の第１の特徴によれば，前記２式を満足させて，可動コアを固定コアの内周面のみで摺動自在に支持することにより，たとえ可動コアが一側方に片寄せされ，且つ弁体が他側方向に傾いた場合でも，可動コアは弁体との接触を回避できる。したがって，可動コアは，これを傾けるような外力を受けることなく，常に弁ハウジングの内周面によってスムーズに案内され，コイルの通電時，固定コアの吸引力に的確に応動して，弁体の開弁応答性の向上に寄与し得る。 According to the first feature of the present invention, by satisfying the above two equations and slidably supporting the movable core only by the inner circumferential surface of the fixed core, even if the movable core is shifted to one side. , and even if the valve body is tilted toward the other side, the movable core can avoid contact with the valve body. Therefore, the movable core is always guided smoothly by the inner circumferential surface of the valve housing without being subjected to any external force that would tilt it, and when the coil is energized, it accurately responds to the attraction force of the fixed core and moves the valve body. This can contribute to improving valve opening responsiveness.

また，閉弁側ストッパを弁ハウジングの内周面に嵌合，固定する一方，可動コアの前端面には，その外周に連なる環状当接部を，コイルの非通電時に閉弁側ストッパの後端面に当接可能に設けるので，コイルの通電遮断時，可動コアは，傾くことなく弁ハウジングの内周面に案内されながら，可動コアの外周に連なる大径の環状当接部が閉弁側ストッパに当接，支承されることになり，可動コアのバウンシングを効果的に抑制することができる。 In addition, while the valve-closing side stopper is fitted and fixed to the inner circumferential surface of the valve housing, an annular abutment part that extends to the outer circumference of the movable core is attached to the front end surface of the movable core after the valve-closing side stopper when the coil is de-energized. Because it is provided so that it can come into contact with the end face, when the coil is de-energized, the movable core is guided by the inner peripheral surface of the valve housing without tilting, and the large-diameter annular contact part that connects to the outer periphery of the movable core is placed on the valve closing side. Since the movable core comes into contact with and is supported by the stopper, bouncing of the movable core can be effectively suppressed.

本発明の第２の特徴によれば，可動コアの前端面には，環状当接部の内周に連なるテーパ状の凹部を設けるので，テーパ状の凹部は，コイルの通電時，可動コアに形成される磁路を絞ることなく，可動コアの軽量化，延いては可動コアの応答性向上に寄与し得る。 According to the second feature of the present invention, the front end surface of the movable core is provided with a tapered recess that extends to the inner periphery of the annular contact portion, so that when the coil is energized, the tapered recess is formed in the movable core. This can contribute to reducing the weight of the movable core and improving the responsiveness of the movable core without constricting the formed magnetic path.

本発明に係る内燃機関用電磁式燃料噴射弁の実施形態を示す縦断面図。1 is a longitudinal sectional view showing an embodiment of an electromagnetic fuel injection valve for an internal combustion engine according to the present invention. 上記燃料噴射弁の閉弁状態における可動コア及び弁部の周辺部を示す拡大図。FIG. 3 is an enlarged view showing the movable core and the peripheral portion of the valve portion of the fuel injection valve in the closed state. 上記燃料噴射弁の開弁状態を示す，図２との対応図。FIG. 3 is a diagram corresponding to FIG. 2 showing the open state of the fuel injection valve.

本発明の実施形態について添付の図１～図３を参照しながら説明する。 Embodiments of the present invention will be described with reference to the accompanying FIGS. 1 to 3.

先ず図１において，内燃機関Ｅのシリンダヘッド５には，燃焼室６に開口する装着孔７が設けられており，燃焼室６に向かって燃料を噴射し得る本発明の電磁式燃料噴射弁Ｉが前記装着孔７に装着される。本発明の電磁式燃料噴射弁Ｉでは，燃料噴射側を前方，その反対側を後方とする。 First, in FIG. 1, a cylinder head 5 of an internal combustion engine E is provided with a mounting hole 7 that opens into a combustion chamber 6, and an electromagnetic fuel injection valve I of the present invention that can inject fuel toward the combustion chamber 6 is installed. is mounted in the mounting hole 7. In the electromagnetic fuel injection valve I of the present invention, the fuel injection side is the front side, and the opposite side is the rear side.

この電磁式燃料噴射弁Ｉの弁ハウジング９は，中空円筒状のハウジングボディ１０と，このハウジングボディ１０の前端部内周に嵌合して溶接される弁座部材１１と，ハウジングボディ１０の後端部外周に前端部を嵌合させてハウジングボディ１０に溶接される磁性円筒体１２と，この磁性円筒体１２の後端部に前端部が同軸に結合される非磁性円筒体１３とで構成される。非磁性円筒体１３の後端部には，中空部１５を有する円筒状の固定コア１４の前端部が同軸に結合され，この固定コア１４の後端部に，前記中空部１５に通じる燃料供給筒１６が一体に且つ同軸に連設される。 The valve housing 9 of this electromagnetic fuel injection valve I includes a hollow cylindrical housing body 10, a valve seat member 11 that fits and is welded to the inner periphery of the front end of the housing body 10, and a rear end of the housing body 10. A magnetic cylindrical body 12 is welded to the housing body 10 with its front end fitted to the outer periphery of the magnetic cylinder 12, and a non-magnetic cylindrical body 13 whose front end is coaxially connected to the rear end of the magnetic cylinder 12. Ru. A front end of a cylindrical fixed core 14 having a hollow part 15 is coaxially connected to the rear end of the non-magnetic cylindrical body 13, and a fuel supply connected to the hollow part 15 is connected to the rear end of the fixed core 14. The tubes 16 are integrally and coaxially connected.

磁性円筒体１２は，その軸方向中間部にフランジ状のヨーク部１２ａを一体に有しており，装着孔７の外端を囲繞するようにしてシリンダヘッド５に設けられる環状凹部１７に収容されるクッション材１８が，シリンダヘッド５及びヨーク部１２ａ間に介装される。 The magnetic cylindrical body 12 has a flange-shaped yoke part 12a integrally in its axially intermediate part, and is accommodated in an annular recess 17 provided in the cylinder head 5 so as to surround the outer end of the mounting hole 7. A cushioning material 18 is interposed between the cylinder head 5 and the yoke portion 12a.

燃料供給筒１６の入口には，オリフィス部材２４と，その下流側に隣接する燃料フィルタ１９とが装着される。この燃料供給筒１６には，図示しない燃料ポンプの吐出口に連なる燃料分配管２０から分岐した燃料供給キャップ２１が環状のシール部材２２を介して嵌合される。燃料供給キャップ２１の頂部にはブラケット２３が係止され，このブラケット２３は，シリンダヘッド５に立設される不図示の支柱にボルト等によりシリンダヘッド５に着脱可能に締結される。 At the entrance of the fuel supply cylinder 16, an orifice member 24 and a fuel filter 19 adjacent to the orifice member 24 on the downstream side are installed. A fuel supply cap 21 branched from a fuel distribution pipe 20 connected to a discharge port of a fuel pump (not shown) is fitted into the fuel supply tube 16 via an annular seal member 22 . A bracket 23 is secured to the top of the fuel supply cap 21, and this bracket 23 is removably fastened to the cylinder head 5 by bolts or the like to a support (not shown) that is erected on the cylinder head 5.

燃料供給キャップ２１と，燃料供給筒１６の中間部に設けられて燃料供給キャップ２１側に臨む環状段部２５との間には，板ばねからなる弾性部材２６が介装される。この弾性部材２６が発揮する弾発力で電磁式燃料噴射弁Ｉがシリンダヘッド５に保持される。 An elastic member 26 made of a leaf spring is interposed between the fuel supply cap 21 and an annular stepped portion 25 provided in the middle of the fuel supply cylinder 16 and facing the fuel supply cap 21 side. The electromagnetic fuel injection valve I is held in the cylinder head 5 by the elastic force exerted by the elastic member 26.

弁座部材１１は，端壁部１１ａを前端部に有して有底円筒状に形成されており，前記端壁部１１ａには，円錐状の弁座２７が形成されると共に，その弁座２７の中心近傍に開口する複数の燃料噴孔２８が設けられる。この弁座部材１１は，燃料噴孔２８を燃焼室６に向けて開口するようにしてハウジングボディ１０の前端部に嵌合，溶接される。即ち弁ハウジング９が，その前端部に弁座２７を有するように構成される。 The valve seat member 11 has a bottomed cylindrical shape with an end wall portion 11a at the front end, and a conical valve seat 27 is formed on the end wall portion 11a. A plurality of fuel nozzle holes 28 are provided that open near the center of the fuel injection hole 27 . The valve seat member 11 is fitted and welded to the front end of the housing body 10 so that the fuel injection hole 28 opens toward the combustion chamber 6. That is, the valve housing 9 is configured to have a valve seat 27 at its front end.

磁性円筒体１２の後端部から固定コア１４に至る外周面にはコイル組立体３０が嵌装される。このコイル組立体３０は，上記外周面に嵌合するボビン３１と，このボビン３１に巻装されるコイル３２とからなり，このコイル組立体３０を囲繞する磁性体のコイルハウジング３３の前端部が磁性円筒体１２と結合される。 A coil assembly 30 is fitted onto the outer peripheral surface of the magnetic cylindrical body 12 from the rear end to the fixed core 14 . This coil assembly 30 consists of a bobbin 31 that fits on the outer peripheral surface, and a coil 32 that is wound around the bobbin 31. The front end of a magnetic coil housing 33 that surrounds this coil assembly 30 is It is combined with the magnetic cylinder 12.

固定コア１４の後端部外周は，コイルハウジング３３の後端部に連なってモールド成形される合成樹脂製の被覆層３４で被覆されており，この被覆層３４には，コイル３２に連なる端子３５を保持するカプラ３４ａが電磁式燃料噴射弁Ｉの一側方に突出するように一体に形成される。 The outer periphery of the rear end of the fixed core 14 is covered with a synthetic resin coating layer 34 that is molded so as to be continuous with the rear end of the coil housing 33 . A coupler 34a holding the electromagnetic fuel injection valve I is integrally formed so as to protrude from one side thereof.

固定コア１４の前端部に，固定コア１４に外周面を連ねるようにして非磁性円筒体１３の後端部が嵌合され，液密に溶接される。 The rear end of the non-magnetic cylindrical body 13 is fitted to the front end of the fixed core 14 so that its outer peripheral surface is connected to the fixed core 14, and welded in a liquid-tight manner.

弁座部材１１から非磁性円筒体１３に至る弁ハウジング９内には，弁体４０と可動コア４１とが収容される。弁体４０は，弁座２７と協働して燃料噴孔２８を開閉する弁部４２に，固定コア１４内まで延びるロッド４３が連設されてなる。そして，弁部４２は，弁座部材１１内で摺動するよう球状に形成され，ロッド４３は弁部４２よりも小径に形成される。弁座部材１１及びロッド４３間には環状の燃料通路４４が画成され，弁部４２の外周面には，弁座部材１１との間に燃料通路を画成する複数の平面部４５が形成される（図２参照）。 A valve body 40 and a movable core 41 are accommodated in the valve housing 9 extending from the valve seat member 11 to the non-magnetic cylindrical body 13. The valve body 40 includes a valve portion 42 that opens and closes the fuel injection hole 28 in cooperation with the valve seat 27, and a rod 43 that extends into the fixed core 14. The valve portion 42 is formed into a spherical shape so as to slide within the valve seat member 11, and the rod 43 is formed to have a smaller diameter than the valve portion 42. An annular fuel passage 44 is defined between the valve seat member 11 and the rod 43, and a plurality of flat parts 45 are formed on the outer circumferential surface of the valve portion 42 to define fuel passages between the valve seat member 11 and the rod 43. (See Figure 2).

図１及び図２に示すように，ロッド４３には，固定コア１４内に配置される開弁側ストッパ４８が固着される。この開弁側ストッパ４８は，固定コア１４の内周面に摺動自在に嵌合するフランジ部４８ａと，このフランジ部４８ａから可動コア４１側に突出する円筒状の軸部４８ｂとで構成されており，そのフランジ部４８ａが溶接によりロッド４３に固着される。 As shown in FIGS. 1 and 2, a valve-opening side stopper 48 disposed within the fixed core 14 is fixed to the rod 43. This valve opening side stopper 48 is composed of a flange portion 48a that is slidably fitted to the inner circumferential surface of the fixed core 14, and a cylindrical shaft portion 48b that protrudes from the flange portion 48a toward the movable core 41 side. The flange portion 48a is fixed to the rod 43 by welding.

而して，弁体４０は，可動コア４１を間に置いて軸方向に離隔した第１及び第２ガイド部４６ａ，４６ｂにより開閉動作を案内される。その第１ガイド部４６ａは，弁部４２を摺動自在に支持する弁座部材１１の内周面であり，第２ガイド部４６ｂは，弁体４０と一体化した開弁側ストッパ４８のフランジ部４８ａを摺動自在に支持する固定コア１４の中空部１５の内周面である。 The opening and closing operations of the valve body 40 are guided by first and second guide portions 46a and 46b that are spaced apart in the axial direction with the movable core 41 interposed therebetween. The first guide portion 46a is the inner peripheral surface of the valve seat member 11 that slidably supports the valve portion 42, and the second guide portion 46b is the flange of the valve opening side stopper 48 integrated with the valve body 40. This is the inner peripheral surface of the hollow part 15 of the fixed core 14 that slidably supports the part 48a.

固定コア１４の中空部１５にはパイプ状のリテーナ５３が嵌挿されてかしめ固定される。このリテーナ５３と，開弁側ストッパ４８のフランジ部４８ａとの間には弁体４０を弁座２７への着座方向，即ち閉弁方向へ付勢する弁ばね５４が縮設される。 A pipe-shaped retainer 53 is fitted into the hollow portion 15 of the fixed core 14 and fixed by caulking. A valve spring 54 is compressed between the retainer 53 and the flange portion 48a of the valve-opening stopper 48, and urges the valve body 40 in the seating direction on the valve seat 27, that is, in the valve-closing direction.

前記可動コア４１は，その後端面（被吸引面４１ａ）を固定コア１４の前端面（吸引面１４ａ）に対向させながら，弁ハウジング９の内周面に摺動自在に嵌合される。その際，可動コア４１は，磁性円筒体１２及び非磁性円筒体１３に跨がって配置される。この可動コア４１は，その中心部に前記ロッド４３に挿通される通孔４１ｂが設けられている。 The movable core 41 is slidably fitted into the inner peripheral surface of the valve housing 9, with its rear end surface (suction surface 41a) facing the front end surface (suction surface 14a) of the fixed core 14. At this time, the movable core 41 is arranged astride the magnetic cylindrical body 12 and the non-magnetic cylindrical body 13. The movable core 41 is provided with a through hole 41b in its center, through which the rod 43 is inserted.

磁性円筒体１２の内周面には，可動コア４１の外周側の前端面に対向する環状の閉弁側ストッパ４９が圧入して固定される。この閉弁側ストッパ４９の位置決めのため，閉弁側ストッパ４９の外周部前端面を支承する環状の位置決め段部４７が磁性円筒体１２の内周に形成される。 An annular valve-closing stopper 49 facing the outer peripheral front end surface of the movable core 41 is press-fitted and fixed to the inner peripheral surface of the magnetic cylindrical body 12 . To position the valve-closing stopper 49, an annular positioning step 47 is formed on the inner periphery of the magnetic cylinder 12 to support the front end surface of the outer peripheral portion of the valve-closing stopper 49.

可動コア４１と前記開弁側ストッパ４８のフランジ４８ａとの間には，可動コア４１を上記閉弁側ストッパ４９に向かって付勢する補助ばね５５が縮設される。この補助ばね５５のセット荷重は，前記弁ばね５４のそれより小さく設定される。 An auxiliary spring 55 is provided between the movable core 41 and the flange 48a of the valve-opening stopper 48 for biasing the movable core 41 toward the valve-closing stopper 49. The set load of this auxiliary spring 55 is set smaller than that of the valve spring 54.

ロッド４３の後端部は，開弁側ストッパ４８のフランジ部４８ａよりも突出し，弁ばね５４の可動端部の内周面に嵌合して，その位置決めの役割を果たしている。また開弁側ストッパ４８の軸部４８ｂは，補助ばね５５の内周面に嵌合して，その位置決めの役割を果たしている。 The rear end of the rod 43 protrudes beyond the flange 48a of the valve-opening stopper 48, fits into the inner peripheral surface of the movable end of the valve spring 54, and plays a positioning role. Further, the shaft portion 48b of the valve-opening side stopper 48 fits into the inner circumferential surface of the auxiliary spring 55, and plays the role of positioning the auxiliary spring 55.

開弁側ストッパ４８のフランジ部４８ａの外周の複数箇所には，固定コア１４の内周面との間に燃料通路を画成する平面部５７が設けられ，また可動コア４１には，環状配列の複数の燃料通孔５８が設けられる。 At multiple locations on the outer periphery of the flange portion 48a of the valve-opening side stopper 48, flat portions 57 are provided that define fuel passages between them and the inner peripheral surface of the fixed core 14. A plurality of fuel holes 58 are provided.

而して，弁体４０が閉弁位置あり，且つ可動コア４１が閉弁側ストッパ４９との当接位置にあるとき，固定コア１４の吸引面１４ａと可動コア４１の被吸引面４１ａとの間には，弁体４０の開閉ストロークに対応する間隔が確保され，そして開弁側ストッパ４８の軸部４８ｂの前端部は，前記間隔の中間位置を占めるようになっている。したがって，コイル３２の通電に伴い固定コア１４が可動コア４１を吸引したときは，可動コア４１は，先ず開弁側ストッパ４８に当接し，次いで開弁側ストッパ４８を伴いながら固定コア１４に吸着されるタイミングとなる。 Therefore, when the valve body 40 is in the valve closing position and the movable core 41 is in the abutment position with the valve closing side stopper 49, the suction surface 14a of the fixed core 14 and the suction surface 41a of the movable core 41 are An interval corresponding to the opening/closing stroke of the valve body 40 is ensured therebetween, and the front end of the shaft portion 48b of the valve-opening side stopper 48 occupies an intermediate position in the interval. Therefore, when the fixed core 14 attracts the movable core 41 as the coil 32 is energized, the movable core 41 first contacts the valve-opening side stopper 48 and then attracts the fixed core 14 with the valve-opening side stopper 48. This is the timing to do so.

ここで，図２に明示するように，前記弁体４０と前記第１及び第２ガイド部４６ａ，４６ｂとの間に設定される第１環状間隙をＧ１，前記弁ハウジング９と前記可動コア４１との間に設定される第２環状間隙をＧ２，前記可動コア４１と前記ロッド４３との間に設定される第３環状間隙をＧ３としたとき，
Ｇ１＜Ｇ２＜Ｇ３・・・・・・（１）
（Ｇ１＋Ｇ２）＜Ｇ３・・・・（２）
上記２式を満足させることにより，可動コア４１は弁ハウジング９の内周面のみによって摺動自在に支持される。 Here, as clearly shown in FIG. 2, the first annular gap set between the valve body 40 and the first and second guide parts 46a and 46b is G1, and the valve housing 9 and the movable core 41 are When G2 is the second annular gap set between the movable core 41 and the rod 43, and G3 is the third annular gap set between the movable core 41 and the rod 43,
G1<G2<G3...(1)
(G1+G2)<G3...(2)
By satisfying the above two equations, the movable core 41 is slidably supported only by the inner peripheral surface of the valve housing 9.

そして，前記可動コア４１の前端面には，その可動コア４１の外周に連なる環状当接部５０が，コイル３２の非通電時に前記閉弁側ストッパ４９の後端面に当接可能に設けられる。また前記可動コア４１の前端面には，環状当接部５０の内周に連なるテーパ状の凹部５１が設けられる。 Further, an annular contact portion 50 that is continuous with the outer periphery of the movable core 41 is provided on the front end surface of the movable core 41 so as to be able to come into contact with the rear end surface of the valve closing side stopper 49 when the coil 32 is not energized. Further, a tapered recess 51 is provided on the front end surface of the movable core 41 and continues to the inner periphery of the annular contact portion 50 .

次に，この実施形態の作用について説明する。 Next, the operation of this embodiment will be explained.

電磁式燃料噴射弁Ｉにおいて，コイル３２の非通電状態では，弁体４０は，弁ばね５４のセット荷重によって押圧されることで，弁座２７に着座して燃料噴孔２８を閉鎖する閉弁状態となる。この閉弁状態では，図示しない燃料ポンプから燃料分配管２０に吐出される高圧燃料が燃料供給キャップ２１を通して燃料供給筒１６に供給され，燃料噴射弁Ｉの内部，即ち燃料供給筒１６，パイプ状のリテーナ５３，固定コア１４，可動コア４１，弁ハウジング９等の内部を満たして待機する。 In the electromagnetic fuel injection valve I, when the coil 32 is in a non-energized state, the valve body 40 is pressed by the set load of the valve spring 54 to close the fuel injection hole 28 by seating on the valve seat 27. state. In this valve-closed state, high-pressure fuel discharged from a fuel pump (not shown) to the fuel distribution pipe 20 is supplied to the fuel supply cylinder 16 through the fuel supply cap 21, and the inside of the fuel injection valve I, that is, the fuel supply pipe 16, is The insides of the retainer 53, fixed core 14, movable core 41, valve housing 9, etc. are filled and standby.

その際，燃料ポンプの吐出圧変動等に起因して燃料分配管２０内に発生する燃料圧力の脈動は，燃料供給筒１６の入口のオリフィス部材２４のオリフィスにより減衰され，燃料噴射弁Ｉ内部への影響を解消，もしくは軽減する。 At this time, the pulsations in the fuel pressure that occur in the fuel distribution pipe 20 due to variations in the discharge pressure of the fuel pump, etc., are attenuated by the orifice of the orifice member 24 at the inlet of the fuel supply cylinder 16, and the pulsations are transferred to the inside of the fuel injection valve I. Eliminate or reduce the impact of

一方，図２に示すように，可動コア４１は，このような閉弁状態では，補助ばね５５のセット荷重によって閉弁側ストッパ４９との当接状態に保持され，固定コア１４との間に所定の前記間隔を保っている。 On the other hand, as shown in FIG. 2, in such a valve-closing state, the movable core 41 is held in contact with the valve-closing stopper 49 by the set load of the auxiliary spring 55, and there is no space between the movable core 41 and the fixed core 14. The predetermined distance is maintained.

このような閉弁状態でコイル３２に通電すると，固定コア１４及び可動コア４１間に生じる磁力により，可動コア４１は，固定コア１４に吸引されるので，先ず，補助ばね５５を圧縮しながら，ロッド４３上を後方へ摺動して開弁側ストッパ４８に当接する。即ち可動コア４１は，その初動時，弁ばね５４よりセット荷重が小さい補助ばね５５を素早く圧縮しながら固定コア１４に近接して，固定コア１４からの吸引力を急増させるので，加速的に移動して開弁側ストッパ４８に当接する。 When the coil 32 is energized in such a valve closed state, the movable core 41 is attracted to the fixed core 14 by the magnetic force generated between the fixed core 14 and the movable core 41, so first, while compressing the auxiliary spring 55, It slides backward on the rod 43 and comes into contact with the valve opening side stopper 48. That is, when the movable core 41 initially moves, it approaches the fixed core 14 while quickly compressing the auxiliary spring 55, which has a smaller set load than the valve spring 54, and rapidly increases the suction force from the fixed core 14, so that it moves at an accelerated pace. and comes into contact with the valve opening side stopper 48.

そして，図３に示すように，可動コア４１は，直ちに開弁側ストッパ４８を伴いながら，弁ばね５４の大なるセット荷重に抗して速やかに更に後方へ移動して可動コア４１の吸引面１４ａに吸着される。 Then, as shown in FIG. 3, the movable core 41 immediately moves further rearward against the large set load of the valve spring 54 while being accompanied by the valve-opening side stopper 48, and moves toward the suction surface of the movable core 41. It is adsorbed by 14a.

こうして可動コア４１と共に後方へ移動する開弁側ストッパ４８は，弁体４０のロッド４３に固定されているので，弁部４２を弁座２７から離座させ，開弁状態とすることができる。 Since the valve-opening stopper 48, which moves rearward together with the movable core 41, is fixed to the rod 43 of the valve body 40, it is possible to displace the valve portion 42 from the valve seat 27 and open the valve.

弁体４０が開弁すると，弁ハウジング９等の内部で待機する高圧燃料が燃料噴孔２８から内燃機関Ｅの燃焼室６に直接噴射される。このようにして，弁体４０の開弁応答性が高められると共に，コイル３２の消費電力の軽減を図ることができる。 When the valve body 40 opens, high-pressure fuel waiting inside the valve housing 9 or the like is directly injected from the fuel injection hole 28 into the combustion chamber 6 of the internal combustion engine E. In this way, the valve-opening response of the valve body 40 can be improved, and the power consumption of the coil 32 can be reduced.

次に，コイル３２への通電を遮断すると，弁ばね５４の付勢力により開弁側ストッパ４８が押動されるので，開弁側ストッパ４８は弁体４０を伴なって弁座２７側に即座に移動し，弁部４２を弁座２７に着座させ，閉弁状態となって燃料噴孔２８からの燃料噴射を停止する。この弁体４０の閉弁状態は，弁ばね５４の大なるセット荷重により確実に保持される。 Next, when the coil 32 is de-energized, the valve opening side stopper 48 is pushed by the biasing force of the valve spring 54, so the valve opening side stopper 48, together with the valve body 40, immediately moves toward the valve seat 27 side. , the valve portion 42 is seated on the valve seat 27, the valve is closed, and fuel injection from the fuel injection hole 28 is stopped. This closed state of the valve body 40 is reliably maintained by a large set load of the valve spring 54.

一方，可動コア４１は，補助ばね５５の付勢力により押圧されて閉弁側ストッパ４９に受け止められる。このとき，可動コア４１の前端面の環状当接部５０が閉弁側ストッパ４９の平坦な後端面に当接し，支承される。 On the other hand, the movable core 41 is pressed by the urging force of the auxiliary spring 55 and received by the valve-closing stopper 49 . At this time, the annular contact portion 50 on the front end surface of the movable core 41 contacts and is supported by the flat rear end surface of the valve-closing stopper 49.

ところで，前記２式を満足させることにより，可動コア４１は弁ハウジング９の内周面のみによって摺動自在に支持されるので，エンジンの振動等により，可動コア４１が一側方に片寄せされ，且つ弁体４０が他側方に傾いた厳しい状態にあっても，可動コア４１の通孔４１ｂの内周面に弁体４０のロッド４３が接触することはない。したがって，可動コア４１は，これを傾けるような外力を受けることなく，常に弁ハウジング９の内周面によりスムーズに案内され，コイルの通電時，固定コア１４の吸引力に的確に応動して，弁体の開弁応答性の向上を図ることができる。また，可動コア４１及び固定コア１４間の第２環状間隙Ｇ２が可動コア４１及びロッド４３間の第３環状間隙Ｇ３より小さく設定されることにより，固定コア１４及び可動コア４１間の磁気抵抗が減少し，これも可動コア４１の応答性の向上に寄与する。 By the way, by satisfying the above two equations, the movable core 41 is slidably supported only by the inner circumferential surface of the valve housing 9, so that the movable core 41 is not pushed to one side due to engine vibration or the like. , and even if the valve body 40 is in a severe state tilted to the other side, the rod 43 of the valve body 40 will not come into contact with the inner peripheral surface of the through hole 41b of the movable core 41. Therefore, the movable core 41 is always guided smoothly by the inner circumferential surface of the valve housing 9 without being subjected to any external force that would tilt it, and responds accurately to the attractive force of the fixed core 14 when the coil is energized. It is possible to improve the valve opening response of the valve body. Furthermore, by setting the second annular gap G2 between the movable core 41 and the fixed core 14 to be smaller than the third annular gap G3 between the movable core 41 and the rod 43, the magnetic resistance between the fixed core 14 and the movable core 41 is reduced. This also contributes to improving the responsiveness of the movable core 41.

また，閉弁側ストッパ４９を弁ハウジング９の内周面に嵌合，固定され，可動コア４１の前端面に，その外周に連なる環状当接部５０が，コイル３２の非通電時，閉弁側ストッパ４９の後端面に当接可能に設けられるので，コイル３２の通電遮断時，可動コア４１は，傾くことなく弁ハウジング９の内周面に案内され，可動コア４１の外周に連なる大径の環状当接部５０が閉弁側ストッパ４９に当接，支承されることになり，可動コア４１のバウンシングを抑制することができる。 Further, the valve closing side stopper 49 is fitted and fixed to the inner circumferential surface of the valve housing 9, and an annular contact portion 50 connected to the outer circumference of the movable core 41 is provided on the front end surface of the movable core 41 to close the valve when the coil 32 is de-energized. Since the movable core 41 is provided so as to be able to come into contact with the rear end surface of the side stopper 49, when the coil 32 is deenergized, the movable core 41 is guided to the inner circumferential surface of the valve housing 9 without tilting, and the large diameter continuous to the outer circumference of the movable core 41 is guided. The annular contact portion 50 contacts and is supported by the valve-closing stopper 49, and bouncing of the movable core 41 can be suppressed.

また，可動コア４１の前端面には，前記環状当接部５０の内周に連なるテーパ状の凹部５１が設けられるので，テーパ状の凹部５１は，コイルの通電時，可動コアに形成される磁路を絞ることなく，可動コア４１の軽量化，延いては可動コア４１の応答性向上に寄与することができる。可動コア４１のバウンシングの抑制は，次のコイル３２の通電時までに可動コア４１のバウンシングを収束させ得ることを意味し，所定の燃料噴射特性を安定させることができる。 Further, since a tapered recess 51 is provided on the front end surface of the movable core 41 and continues to the inner circumference of the annular contact portion 50, the tapered recess 51 is formed in the movable core when the coil is energized. Without constricting the magnetic path, it is possible to contribute to reducing the weight of the movable core 41 and, by extension, improving the responsiveness of the movable core 41. Suppressing the bouncing of the movable core 41 means that the bouncing of the movable core 41 can be converged by the time of the next energization of the coil 32, and predetermined fuel injection characteristics can be stabilized.

以上，本発明の実施の形態について説明したが，本発明は上記実施形態に限定されるものではなく，特許請求の範囲に記載された本発明を逸脱することなく種々の設計変更を行うことが可能である。 Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various design changes can be made without departing from the scope of the present invention as set forth in the claims. It is possible.

Ｉ・・・・電磁式燃料噴射弁
９・・・・弁ハウジング
１４・・・固定コア
２７・・・弁座
３２・・・コイル
４０・・・弁体
４１・・・可動コア
４１ｂ・・可動コアの通孔
４２・・・弁部
４３・・・ロッド
４６ａ，４６ｂ・・・弁体の一対のガイド部
４８・・・開弁側ストッパ
４９・・・閉弁側ストッパ
５０・・・環状当接部
５１・・・凹部
５４・・・弁ばね
５５・・・補助ばね I...Solenoid fuel injection valve 9...Valve housing 14...Fixed core 27...Valve seat 32...Coil 40...Valve body 41...Movable core 41b...Movable Core through hole 42... Valve part 43... Rods 46a, 46b... Pair of guide parts 48 for valve body... Valve opening side stopper 49... Valve closing side stopper 50... Annular stop Contact portion 51... recess 54... valve spring 55... auxiliary spring

Claims (2)

前端部に弁座（２７）を有する弁ハウジング（９）と，該弁ハウジング（９）の後端に連設される中空の固定コア（１４）と，該固定コア（１４）の外周に配設されるコイル（３２）と，前記弁座（２７）と協働する弁部（４２）にロッド（４３）が連設されてなる弁体（４０）と，前記固定コア（１４）の前端面に対向しながら前記弁ハウジング（９）内に摺動可能に配設され，中心部には，前記ロッド（４３）に貫通される通孔（４１ｂ）を有する可動コア（４１）と，前記ロッド（４３）に固定されると共に前記固定コア（１４）の中空部に摺動可能に配設され，前記コイル（３２）の通電時，前記固定コア（１４）に吸引される前記可動コア（４１）により押動されて前記弁体（４０）を開弁作動させる開弁側ストッパ（４８）と，前記可動コア（４１）の前端面に対向して配設される閉弁側ストッパ（４９）と，前記弁体（４０）を閉弁方向に付勢する弁ばね（５４）と，前記コイル（３２）の非通電時，前記可動コア（４１）を前記開弁側ストッパ（４８）から離反させて前記閉弁側ストッパ（４９）に当接させるように付勢して，前記弁体（４０）の閉弁を許容する補助ばね（５５）とを備え，更に前記弁体（４０）の開閉動作をガイドすべく，前記可動コア（４１）を挟んで弁体（４０）の軸方向に並ぶ一対のガイド部（４６ａ，４６ｂ）を備える電磁式燃料噴射弁であって，
前記弁体（４０）と前記一対のガイド部（４６ａ，４６ｂ）との間に設定される第１環状間隙をＧ１，前記弁ハウジング（９）と可動コア（４１）との間に設定される第２環状間隙をＧ２，前記可動コア（４１）と前記ロッド（４３）との間に設定される第３環状間隙をＧ３としたとき，
Ｇ１＜Ｇ２＜Ｇ３・・・・・・（１）
（Ｇ１＋Ｇ２）＜Ｇ３・・・・（２）
上記２式を満足させて，前記可動コア（４１）を前記弁ハウジング（９）の内周面のみで摺動自在に支持し，前記閉弁側ストッパ（４９）を前記弁ハウジング（９）の内周面に嵌合，固定する一方，前記可動コア（４１）の前端面には，その外周に連なる環状当接部（５０）を，前記コイル（３２）の非通電時に前記閉弁側ストッパ（４９）の後端面に当接可能に設けることを特徴とする，電磁式燃料噴射弁。 A valve housing (9) having a valve seat (27) at the front end, a hollow fixed core (14) connected to the rear end of the valve housing (9), and arranged around the outer periphery of the fixed core (14). a coil (32) provided therein, a valve body (40) in which a rod (43) is connected to a valve portion (42) that cooperates with the valve seat (27), and a front end of the fixed core (14). A movable core (41) is slidably disposed in the valve housing (9) while facing the surface thereof, and has a through hole (41b) in the center that is penetrated by the rod (43); The movable core (43) is fixed to the rod (43) and is slidably disposed in the hollow part of the fixed core (14), and is attracted to the fixed core (14) when the coil (32) is energized. a valve-opening side stopper (48) that is pushed by the valve body (41) to open the valve body (40), and a valve-closing side stopper (49) disposed opposite to the front end surface of the movable core (41). ), a valve spring (54) that biases the valve body (40) in the valve closing direction, and a valve spring (54) that pushes the movable core (41) away from the valve opening side stopper (48) when the coil (32) is not energized. an auxiliary spring (55) that allows the valve body (40) to close by urging the valve body (40) to separate and come into contact with the valve closing side stopper (49); An electromagnetic fuel injection valve comprising a pair of guide portions (46a, 46b) aligned in the axial direction of the valve body (40) with the movable core (41) in between to guide the opening and closing operations of the valve,
A first annular gap G1 is set between the valve body (40) and the pair of guide parts (46a, 46b), and a first annular gap is set between the valve housing (9) and the movable core (41). When the second annular gap is G2 and the third annular gap between the movable core (41) and the rod (43) is G3,
G1<G2<G3...(1)
(G1+G2)<G3...(2)
Satisfying the above two equations, the movable core (41) is slidably supported only on the inner peripheral surface of the valve housing (9), and the valve closing side stopper (49) is mounted on the valve housing (9). While the movable core (41) is fitted and fixed to the inner circumferential surface, an annular contact portion (50) continuous to the outer circumference is provided on the front end surface of the movable core (41) to engage the valve closing side stopper when the coil (32) is not energized. (49) An electromagnetic fuel injection valve, characterized in that it is provided so as to be able to come into contact with the rear end surface. 前記可動コア（４１）の前端面には，前記環状当接部（５０）の内周に連なるテーパ状の凹部（５１）を設けることを特徴とする請求項１記載の電磁式燃料噴射弁。 2. The electromagnetic fuel injection valve according to claim 1, wherein the front end surface of the movable core (41) is provided with a tapered recess (51) that extends to the inner periphery of the annular contact portion (50).