JP2017089446A

JP2017089446A - Injection valve

Info

Publication number: JP2017089446A
Application number: JP2015218248A
Authority: JP
Inventors: 大貴羽山; Daiki Hayama; 原田　明典; Akinori Harada; 原田　　明典
Original assignee: Denso Corp
Current assignee: Denso Corp
Priority date: 2015-11-06
Filing date: 2015-11-06
Publication date: 2017-05-25
Anticipated expiration: 2035-11-06
Also published as: JP6508477B2

Abstract

PROBLEM TO BE SOLVED: To provide an injection valve for spraying liquid which can make compatible both the suppression of the deterioration of the accuracy of a flow rate, and the suppression of the adhesion of liquid to an injection plate, while promoting the atomization of a liquid spray.SOLUTION: A flow-in hollow chamber 13 interposed between a valve opening of a nozzle body and an injection hole is formed at a plate face which contacts with the nozzle body of an injection plate of an injection valve. A part 13a (flow-in part) of the flow-in hollow chamber 13 intrudes into the valve opening 10, and a remaining part 13b (residual part) is covered with the nozzle body. The injection hole 11 is formed at the residual part 13b. The flow-in hollow chamber 13 has two edge lines 13d which are formed in fan-shaped base shapes, that is, in an opposing relationship, and is formed into a shape in which a width between the edge lines 13d gradually becomes smaller as progressing toward other end sides from one-end sides of the edge lines 13d. The flow-in part 13a is set at an end part side in which the width between the edge lines 13d is wider out of both ends of the edge lines 13d.SELECTED DRAWING: Figure 3

Description

本発明は、尿素水や燃料等の液体を噴射する噴射弁に関する。 The present invention relates to an injection valve that injects a liquid such as urea water or fuel.

内燃機関の燃料噴射装置や排ガス装置のための噴射弁は、先端に弁開口が形成され、その弁開口を取り囲む弁座を有したニードル収容室が内部に形成されたノズルボディと、ニードル収容室において弁座に着座した閉弁位置と、弁座から離座した開弁位置との間で移動可能に設けられたニードルと、ノズルボディの先端面であるボディ端面を覆うように設けられ、噴孔が形成された噴孔プレートとを含んで構成されている。 An injection valve for a fuel injection device or an exhaust gas device of an internal combustion engine includes a nozzle body in which a valve opening is formed at a tip and a needle housing chamber having a valve seat surrounding the valve opening is formed therein, and a needle housing chamber The needle is movably provided between the valve-closed position seated on the valve seat and the valve-opened position separated from the valve seat, and the body end surface, which is the tip surface of the nozzle body, is provided so as to cover the nozzle. And a nozzle hole plate in which holes are formed.

この種の噴射弁に関する技術として、従来、ノズルボディの弁開口に対して噴孔が半径方向にずらされており、弁開口と噴孔との間に流入中空室を介在させた噴射弁の提案がある（特許文献１参照）。特許文献１の噴射弁では、噴孔プレートの、ノズルボディ（弁座体）に面したプレート面に流入中空室としての凹部が形成されている。その凹部は、一部が弁開口に突入し、凹部の残りの部分がノズルボディによって覆われている。噴孔は、ノズルボディによって覆われる凹部の部分の内側で、凹部の底面に形成されている。また、凹部は、平面視で円形、長円形又は楕円形に形成される。この特許文献１の噴射弁によれば、弁開口から流入中空室に流入した液体に対してＳ字型の流れが得られ、この流れにより噴孔における噴霧を助成する流れの扇形の拡散が促進できるとしている。 As a technology related to this type of injection valve, conventionally, an injection valve has been proposed in which the injection hole is radially displaced with respect to the valve opening of the nozzle body, and an inflow hollow chamber is interposed between the valve opening and the injection hole. (See Patent Document 1). In the injection valve of Patent Document 1, a recess as an inflow hollow chamber is formed on the plate surface of the nozzle hole plate facing the nozzle body (valve seat body). A part of the concave part enters the valve opening, and the remaining part of the concave part is covered with the nozzle body. The nozzle hole is formed on the bottom surface of the concave portion inside the concave portion covered by the nozzle body. The recess is formed in a circular shape, an oval shape, or an elliptical shape in plan view. According to the injection valve of Patent Document 1, an S-shaped flow is obtained with respect to the liquid flowing into the inflow hollow chamber from the valve opening, and this flow promotes the fan-shaped diffusion of the flow that assists the spray in the nozzle hole. I can do it.

特開２０１２−５０３１２８号公報JP 2012-503128 A

特許文献１の技術を適用すれば、噴射弁から噴射される液体噴霧を微粒化させることができる。しかし、流入中空室の一部のみが弁開口に面する構成なので、流入中空室の弁開口に面した部分である流入部で流量が絞られてしまい、流量精度が悪化する。流量精度の悪化を抑制するために、流入中空室の径を大きくして流量部の面積を大きくすることが考えられる。しかし、流入中空室の径を大きくすると、流入中空室において液体が噴孔に多方向から流れ込むようになり、結果、噴孔から噴射した液体が噴孔プレートに飛び散って、噴孔プレートへの液体の付着量が増えてしまう。 If the technique of patent document 1 is applied, the liquid spray injected from an injection valve can be atomized. However, since only a part of the inflow hollow chamber faces the valve opening, the flow rate is reduced at the inflow portion that is the portion facing the valve opening of the inflow hollow chamber, and the flow rate accuracy deteriorates. In order to suppress the deterioration of the flow rate accuracy, it is conceivable to increase the diameter of the inflow hollow chamber to increase the area of the flow rate part. However, when the diameter of the inflow hollow chamber is increased, the liquid flows into the injection hole from multiple directions in the inflow hollow chamber. As a result, the liquid ejected from the injection hole is scattered in the injection hole plate, and the liquid to the injection hole plate The amount of adhesion will increase.

本発明は上記問題に鑑みてなされたものであり、液体噴霧の微粒化を促進させつつ、流量精度の悪化の抑制と、噴孔プレートへの液体付着の抑制とを両立させることができる噴射弁を提供することを課題とする。 The present invention has been made in view of the above problems, and an injection valve capable of achieving both suppression of deterioration in flow rate accuracy and suppression of liquid adhesion to the nozzle hole plate while promoting atomization of liquid spray. It is an issue to provide.

上記課題を解決するために、本発明の噴射弁は、先端に弁開口（１０）が形成され、その弁開口を取り囲む弁座（４）を有したニードル収容室（３）が内部に形成されたノズルボディ（２）と、
前記ニードル収容室において前記弁座に着座した閉弁位置と、前記弁座から離座した開弁位置との間で移動可能に設けられたニードル（５）と、
前記ノズルボディの先端面であるボディ端面（２ａ）を覆うように設けられ、少なくとも１つの噴孔（１１）が形成された噴孔プレート（８）とを備え、
前記噴孔プレートの前記ボディ端面に接したプレート面（８ａ）又は前記ボディ端面に凹部（１３、１６）が形成されており、その凹部は、一部（１３ａ、１６ａ）が前記弁開口に面しており、残りの部分（１３ｂ、１６ｂ）が、前記プレート面と前記ボディ端面のうち前記凹部が形成されていない方で覆われており、
前記噴孔は、前記弁開口に対して半径方向にずれた位置で前記凹部に繋がっており、
前記凹部は、平面視で見て対向する位置関係にある２つの縁線（１３ｄ、１６ｄ）を有し、それら２つの縁線間の幅が前記縁線の一端側から他端側にいくにしたがって次第に小さくなり、前記縁線の両端のうち前記幅が広い端部側の前記縁線間の部分が前記弁開口に面していることを特徴とする。 In order to solve the above problems, the injection valve of the present invention has a valve opening (10) formed at the tip, and a needle housing chamber (3) having a valve seat (4) surrounding the valve opening is formed inside. Nozzle body (2),
A needle (5) provided movably between a valve closing position seated on the valve seat in the needle housing chamber and a valve opening position separated from the valve seat;
A nozzle hole plate (8) provided to cover the body end surface (2a), which is the tip surface of the nozzle body, and having at least one nozzle hole (11) formed thereon;
Recesses (13, 16) are formed in the plate surface (8a) in contact with the body end surface of the nozzle hole plate or the body end surface, and a part (13a, 16a) of the recess faces the valve opening. The remaining portions (13b, 16b) are covered with the plate surface and the body end surface that are not formed with the recesses,
The nozzle hole is connected to the recess at a position shifted in the radial direction with respect to the valve opening,
The concave portion has two edge lines (13d, 16d) that are opposed to each other when seen in a plan view, and the width between the two edge lines goes from one end side to the other end side of the edge line. Therefore, the width gradually decreases, and a portion between the edge lines on the wide end side of both ends of the edge line faces the valve opening.

また、本発明を上記と別の表現であらわすと、本発明は、先端に弁開口（１０）が形成され、その弁開口を取り囲む弁座（４）を有したニードル収容室（３）が内部に形成されたノズルボディ（２）と、
前記ニードル収容室において前記弁座に着座した閉弁位置と、前記弁座から離座した開弁位置との間で移動可能に設けられたニードル（５）と、
前記ノズルボディの先端面であるボディ端面（２ａ）を覆うように設けられ、少なくとも１つの噴孔（１１）が形成された噴孔プレート（８）とを備え、
前記噴孔プレートの前記ボディ端面に接したプレート面（８ａ）又は前記ボディ端面に凹部（１３、１６）が形成されており、その凹部は、一部（１３ａ、１６ａ）が前記弁開口に面しており、残りの部分（１３ｂ、１６ｂ）が、前記プレート面と前記ボディ端面のうち前記凹部が形成されていない方で覆われており、
前記噴孔は、前記弁開口に対して半径方向にずれた位置で前記凹部に繋がっており、
前記凹部のうち前記弁開口に面した部分を流入部、前記凹部を平面視で見たときの面内方向の直線のうち、前記凹部の縁線（１３ｄ、１３ｅ、１６ｄ）と前記弁開口の縁線との両交点（１４）間の中点（１５）を通り、その両交点を通る直線（Ｌ３）に直角な直線（Ｌ４）を中心線として、
前記凹部は、前記中心線に沿って前記流入部から離れるにしたがって前記中心線に直角な方向における幅が次第に小さくなる形状に形成されたことを特徴とする。 Further, when the present invention is expressed by a different expression from the above, the present invention includes a needle housing chamber (3) having a valve opening (10) formed at the tip and having a valve seat (4) surrounding the valve opening. A nozzle body (2) formed on
A needle (5) provided movably between a valve closing position seated on the valve seat in the needle housing chamber and a valve opening position separated from the valve seat;
A nozzle hole plate (8) provided to cover the body end surface (2a), which is the tip surface of the nozzle body, and having at least one nozzle hole (11) formed thereon;
Recesses (13, 16) are formed in the plate surface (8a) in contact with the body end surface of the nozzle hole plate or the body end surface, and a part (13a, 16a) of the recess faces the valve opening. The remaining portions (13b, 16b) are covered with the plate surface and the body end surface that are not formed with the recesses,
The nozzle hole is connected to the recess at a position shifted in the radial direction with respect to the valve opening,
Of the concave portion, the portion facing the valve opening is an inflow portion, and among the straight lines in the in-plane direction when the concave portion is viewed in plan view, the edge lines (13d, 13e, 16d) of the concave portion and the valve opening A straight line (L4) perpendicular to the straight line (L3) passing through the middle point (15) between the two intersections (14) with the edge line and passing through the two intersections is used as the center line.
The concave portion is formed in a shape in which a width in a direction perpendicular to the center line gradually decreases as the distance from the inflow portion increases along the center line.

本発明によれば、一部が弁開口に面しており、残りの部分が、プレート面とボディ端面のうち凹部が形成されていない方で覆われた凹部（流入中空室）が形成され、噴孔が弁開口に対して半径方向にずれた位置で凹部に繋がっているので、特許文献１と同様に、弁開口に流入した液体に対してＳ字型の流れを得ることができる。これにより、噴霧の微粒化を促進できる。さらに、本発明の凹部は、凹部への液体流入部から離れるにしたがって次第に幅が小さくなる形状に形成されているので、特許文献１のように円形ベースの凹部に比べて、流入部の面積を大きくしたとしても、噴孔への液体の流れ込み方向が多方向になるのを抑制できる。よって、流量精度の悪化の抑制と、噴孔プレートへの液体付着の抑制とを両立させることができる。 According to the present invention, a concave portion (inflow hollow chamber) is formed, part of which faces the valve opening, and the remaining portion is covered with the plate surface and the body end surface where the concave portion is not formed. Since the nozzle hole is connected to the recess at a position shifted in the radial direction with respect to the valve opening, an S-shaped flow can be obtained with respect to the liquid flowing into the valve opening, as in Patent Document 1. Thereby, atomization of spray can be promoted. Furthermore, since the concave portion of the present invention is formed in a shape that gradually decreases in width as it moves away from the liquid inflow portion into the concave portion, the area of the inflow portion is reduced as compared with the concave portion of the circular base as in Patent Document 1. Even if it enlarges, it can suppress that the flow direction of the liquid into a nozzle hole turns into multiple directions. Therefore, it is possible to achieve both suppression of deterioration in flow rate accuracy and suppression of liquid adhesion to the nozzle hole plate.

噴射弁の先端側の断面図である。It is sectional drawing of the front end side of an injection valve. 図１のＡ部（噴孔辺り）の拡大図である。It is an enlarged view of the A section (around a nozzle hole) of FIG. 図２のＢ矢視方向から流入中空室を見た平面図である。It is the top view which looked at the inflow hollow chamber from the B arrow direction of FIG. 扇型ベースの流入中空室と円形ベースの流入中空室のそれぞれで、流入中空室内での尿素水の流速ベクトルを示して、噴孔への尿素水の流れ込みの態様を説明する図である。It is a figure explaining the flow mode of urea water to an injection hole by showing the flow velocity vector of urea water in each inflow hollow chamber in each of the inflow hollow chamber of a fan type base and the inflow hollow chamber of a circular base. 扇型ベースの流入中空室を採用した場合の噴孔から噴射された尿素水噴霧の態様を示した図である。It is the figure which showed the aspect of the urea water spray injected from the nozzle hole at the time of employ | adopting the fan-shaped base inflow hollow chamber. 円形ベースの流入中空室を採用した場合の噴孔から噴射された尿素水噴霧の態様を示した図である。It is the figure which showed the aspect of the urea water spray injected from the nozzle hole at the time of employ | adopting the inflow hollow chamber of a circular base. 噴孔と流入部との面積比と、噴射量のずれ量との関係を示した図である。It is the figure which showed the relationship between the area ratio of a nozzle hole and an inflow part, and the deviation | shift amount of injection amount. 流入中空室の角度と、噴孔と流入中空室の壁面との間の長さの和（噴孔壁面長さの和）との関係を示した図である。It is the figure which showed the relationship between the angle of an inflow hollow chamber, and the sum of the length (injection hole wall surface length) between a nozzle hole and the wall surface of an inflow hollow chamber. 流入中空室及び噴孔の平面図であり、流入中空室の角度と、噴孔壁面長さとを示した図である。It is a top view of an inflow hollow chamber and an injection hole, and is a figure showing an angle of an inflow hollow chamber and an injection hole wall surface length. 変形例を説明する図であり、流入中空室に２つの噴孔が形成された例を示した図である。It is a figure explaining a modification and is a figure showing an example in which two nozzle holes were formed in the inflow hollow chamber. 変形例を説明する図であり、円弧相当縁線を直線状とした流入中空室の平面図である。It is a figure explaining a modification and is a top view of the inflow hollow chamber which made the circular arc equivalent edge line into linear form. 変形例を説明する図であり、円弧相当縁線の曲率を小さくした流入中空室の平面図である。It is a figure explaining a modification and it is a top view of the inflow hollow chamber which made the curvature of an arc equivalent edge line small. 変形例を説明する図であり、円弧相当縁線の曲率を大きくした流入中空室の平面図である。It is a figure explaining a modification and is a top view of the inflow hollow chamber which enlarged the curvature of an arc equivalent edge line. 変形例を説明する図であり、流入中空室の先端により近い位置に噴孔が形成された流入中空室の平面図である。It is a figure explaining a modification and is a top view of the inflow hollow chamber in which the nozzle hole was formed in the position nearer the front-end | tip of an inflow hollow chamber. 変形例を説明する図であり、半径相当縁線を外側に凸となる形状とした流入中空室の平面図である。It is a figure explaining a modification and it is a top view of the inflow hollow chamber which made the shape where a radius equivalent edge line becomes convex outside. 変形例を説明する図であり、半径相当縁線を内側に凸となる形状とした流入中空室の平面図である。It is a figure explaining a modification and it is a top view of the inflow hollow chamber which made the shape which becomes a radius equivalent edge line convex inward. 変形例を説明する図であり、先端角度が小さい流入中空室の平面図である。It is a figure explaining a modification and is a top view of an inflow hollow chamber with a small tip angle. 変形例を説明する図であり、先端角度が大きい流入中空室の平面図である。It is a figure explaining a modification and is a top view of an inflow hollow chamber with a large tip angle. 変形例を説明する図であり、先端を尖った形状にした流入中空室の平面図である。It is a figure explaining a modification and it is a top view of the inflow hollow chamber which made the front-end | tip sharp shape. 変形例を説明する図であり、先端を平らにした流入中空室の平面図である。It is a figure explaining a modification and is a top view of the inflow hollow chamber which made the front-end | tip flat. 変形例を説明する図であり、流入中空室の中心線に対してずれた位置に噴孔が形成された図である。It is a figure explaining a modification and it is a figure in which the nozzle hole was formed in the position shifted with respect to the centerline of an inflow hollow chamber. 変形例を説明する図であり、流入中空室の側面と底面との接続部にＲが形成された流入中空室の断面図である。It is a figure explaining a modification and is a sectional view of the inflow hollow chamber in which R is formed in the connection part of the side and bottom of the inflow hollow chamber. 変形例を説明する図であり、流入中空室の側面と底面との接続部が直角に形成された流入中空室の断面図である。It is a figure explaining a modification and is a sectional view of the inflow hollow chamber in which the connecting portion between the side surface and the bottom surface of the inflow hollow chamber is formed at a right angle. 変形例を説明する図であり、流入中空室の側面が底面に対して傾斜した流入中空室の断面図である。It is a figure explaining a modification and it is sectional drawing of the inflow hollow chamber in which the side surface of the inflow hollow chamber inclined with respect to the bottom face. 変形例を説明する図であり、ノズルボディ側に流入中空室が形成された噴射弁の先端側の断面図である。It is a figure explaining a modification and is sectional drawing of the front end side of the injection valve in which the inflow hollow chamber was formed in the nozzle body side. 図２５のＣ部の拡大図である。It is an enlarged view of the C section of FIG. 図２６のＤ矢視方向から流入中空室及び噴孔を見た図である。It is the figure which looked at the inflow hollow chamber and the nozzle hole from the D arrow direction of FIG. 図２６のＥ矢視方向から流入中空室及び噴孔を見た図である。It is the figure which looked at the inflow hollow chamber and the nozzle hole from the E arrow direction of FIG.

以下、本発明の実施形態を図面を参照して説明する。図１は、本発明が適用された噴射弁の先端側の断面図を示している。図１の噴射弁１は、車両に搭載されたディーゼルエンジン等の内燃機関の排気管に設置されて、排気管内に還元剤としての尿素水を噴射する装置である。噴射弁１より下流の排気管には排気ガス中のＮＯｘを選択的に還元浄化するＳＣＲ触媒が設置されている。噴射弁１から添加された尿素水が排気熱により加水分解されることによりアンモニア（ＮＨ３）が生成される。そのアンモニアとＮＯｘとの還元反応がＳＣＲ触媒において行われることで、ＮＯｘは水や窒素に分解（浄化）する。このように、噴射弁１は尿素ＳＣＲシステムの一部を構成する。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a cross-sectional view of the tip side of an injection valve to which the present invention is applied. An injection valve 1 in FIG. 1 is a device that is installed in an exhaust pipe of an internal combustion engine such as a diesel engine mounted on a vehicle and injects urea water as a reducing agent into the exhaust pipe. An SCR catalyst that selectively reduces and purifies NOx in the exhaust gas is installed in the exhaust pipe downstream of the injection valve 1. The urea water added from the injection valve 1 is hydrolyzed by the exhaust heat, so that ammonia (NH3) is generated. The reduction reaction of ammonia and NOx is performed in the SCR catalyst, so that NOx is decomposed (purified) into water and nitrogen. Thus, the injection valve 1 constitutes a part of the urea SCR system.

噴射弁１の先端側は、ノズルボディ２と、ノズルボディ２の先端に配置された噴孔プレート８と、ノズルボディ２内に配置されたニードル５とを備える。ノズルボディ２は、略円筒形状に形成されており、詳しくは、先端に平面視円形の弁開口１０（図２参照）が形成され、その弁開口１０を取り囲む弁座４を有したニードル収容室３が内部に形成されている。そのニードル収容室３はノズルボディ２の中心軸線Ｌ１の方向に延設されている。弁座４は、ニードル収容室３の先端側において先端（弁開口１０）に近づくにつれて内径が小さくなる円錐状の内周面に設定されている。弁座４の最小内径部（縁部）と弁開口１０とが繋がっている。以下では、中心軸線Ｌ１は、噴射弁１の中心軸線であるとして説明する。 The distal end side of the injection valve 1 includes a nozzle body 2, an injection hole plate 8 disposed at the distal end of the nozzle body 2, and a needle 5 disposed in the nozzle body 2. The nozzle body 2 is formed in a substantially cylindrical shape, and more specifically, a needle accommodating chamber having a valve opening 10 (see FIG. 2) having a circular shape in plan view at the tip and having a valve seat 4 surrounding the valve opening 10. 3 is formed inside. The needle housing chamber 3 extends in the direction of the central axis L1 of the nozzle body 2. The valve seat 4 is set to a conical inner peripheral surface whose inner diameter becomes smaller as it approaches the tip (valve opening 10) on the tip side of the needle housing chamber 3. The minimum inner diameter (edge) of the valve seat 4 and the valve opening 10 are connected. In the following description, it is assumed that the central axis L1 is the central axis of the injection valve 1.

ニードル５は、棒状に形成されて、ニードル収容室３においてニードル軸線の方向へ往復移動可能に収容されている。ニードル５は、ノズルボディ２と概ね同軸上に配置されている。ニードル５は、ニードル収容室３の径よりも小さい径に形成されている。そのため、ニードル５の外周面と、ノズルボディ２の内周面（ニードル収容室３の面）との間に空間部７が形成される。その空間部７は尿素水が流通する尿素水通路として機能する。また、ニードル５の先端部には、弁座４に当接可能なシート部６が形成されている。 The needle 5 is formed in a rod shape and is housed in the needle housing chamber 3 so as to be capable of reciprocating in the direction of the needle axis. The needle 5 is disposed substantially coaxially with the nozzle body 2. The needle 5 is formed with a diameter smaller than the diameter of the needle housing chamber 3. Therefore, a space portion 7 is formed between the outer peripheral surface of the needle 5 and the inner peripheral surface of the nozzle body 2 (the surface of the needle housing chamber 3). The space 7 functions as a urea water passage through which urea water flows. Further, a seat portion 6 capable of contacting the valve seat 4 is formed at the tip portion of the needle 5.

噴射弁１は、ニードル５を駆動するソレノイド等から構成された駆動部（図示外）を備えている。駆動部のソレノイドが通電されていないときは、シート部６が弁座４に着座することで、尿素水通路７と、後述の噴孔１１（図２参照）とが遮断されて、噴孔１１からの尿素水噴射が停止される。ソレノイドが通電されると、ニードル５が弁座４から離れる方向に移動し、この移動により、尿素水通路７が開放されて、尿素水通路７の尿素水が弁開口１０を介して後述の流入中空室１３（図２参照）に流入し、流入中空室１３に形成された噴孔１１から尿素水が噴射される。このように、ニードル５は、弁座４に着座した閉弁位置と、弁座４から離座した開弁位置との間で移動可能に設けられている。 The injection valve 1 includes a drive unit (not shown) configured from a solenoid or the like that drives the needle 5. When the solenoid of the drive unit is not energized, the seat portion 6 is seated on the valve seat 4, whereby the urea water passage 7 and a later-described injection hole 11 (see FIG. 2) are blocked, and the injection hole 11. The urea water injection from is stopped. When the solenoid is energized, the needle 5 moves in a direction away from the valve seat 4, whereby the urea water passage 7 is opened by this movement, and the urea water in the urea water passage 7 flows through the valve opening 10 to be described later. It flows into the hollow chamber 13 (see FIG. 2), and urea water is injected from the injection hole 11 formed in the inflow hollow chamber 13. As described above, the needle 5 is provided so as to be movable between the valve-closed position seated on the valve seat 4 and the valve-opened position separated from the valve seat 4.

噴孔プレート８は、ノズルボディ２の先端面２ａであるボディ端面を覆う（言い換えると接触する）ように設けられている。噴孔プレート８は有底の円筒形状に形成され、すなわち筒状部８ｃと、その筒状部８ｃの一方の端部に繋がって筒状部８ｃに直角な設けられた平面部８ｄとから構成されている。平面部８ｄは平面視で円状に形成される。噴孔プレート８（筒状部８ｃ、平面部８ｄ）は、例えば、板厚が一定の板部材をプレス加工することにより形成される。 The nozzle hole plate 8 is provided so as to cover (in other words, contact with) the body end surface that is the front end surface 2 a of the nozzle body 2. The nozzle hole plate 8 is formed in a bottomed cylindrical shape, that is, composed of a cylindrical portion 8c and a flat surface portion 8d connected to one end portion of the cylindrical portion 8c and provided at right angles to the cylindrical portion 8c. Has been. The flat portion 8d is formed in a circular shape in plan view. The nozzle hole plate 8 (cylindrical part 8c, plane part 8d) is formed, for example, by pressing a plate member having a constant plate thickness.

噴孔プレート８は、ノズルボディ２の外周面に筒状部８ｃが嵌め込まれる形で設けられる。その嵌め込まれた部分において、筒状部８ｃの内周面と、ノズルボディ２の外周面とが溶接等で接続されている。また、平面部８ｄのボディ端面２ａ側の面８ａ（図２参照）であるプレート面は、弁開口１０を閉塞しつつボディ端面２ａに接触している。 The nozzle hole plate 8 is provided in a form in which the cylindrical portion 8 c is fitted into the outer peripheral surface of the nozzle body 2. In the fitted portion, the inner peripheral surface of the cylindrical portion 8c and the outer peripheral surface of the nozzle body 2 are connected by welding or the like. Further, the plate surface which is the surface 8a (see FIG. 2) on the body end surface 2a side of the flat portion 8d is in contact with the body end surface 2a while closing the valve opening 10.

図２に示すように、プレート面８ａには、弁開口１０と噴孔１１との間に介在する流入中空室として機能する有底の凹部１３が形成されている。なお、以下では凹部１３を流入中空室と言う。流入中空室１３は、一部１３ａが弁開口１０に突入することにより弁開口１０に面しており、残りの部分１３ｂがボディ端面２ａで覆われる形に形成されている。以下では、流入中空室１３のうち弁開口１０に面した部分１３ａを流入部といい、残りの部分１３ｂを残余部という。 As shown in FIG. 2, a bottomed recess 13 that functions as an inflow hollow chamber interposed between the valve opening 10 and the injection hole 11 is formed on the plate surface 8 a. Hereinafter, the recess 13 is referred to as an inflow hollow chamber. The inflow hollow chamber 13 faces the valve opening 10 when a part 13a enters the valve opening 10, and the remaining part 13b is covered with the body end face 2a. Below, the part 13a which faced the valve opening 10 among the inflow hollow chambers 13 is called an inflow part, and the remaining part 13b is called a remainder part.

図３に示すように、流入中空室１３は、平面視で扇型ベースに形成されている。なお、図３において斜線ハッチングの部分１３ａが流入部であり、ハッチングされていない部分１３ｂが残余部である。流入中空室１３は、詳しくは、平面視で見て、扇型の半径部に相当する対向する位置関係にある２つの縁線１３ｄと、扇型の円弧部に相当する縁線１３ｅとを有した形状に形成される。以下では、縁線１３ｄを半径相当縁線１３ｄといい、縁線１３ｅを円弧相当縁線という。円弧相当縁線１３ｅは外側に凸の円弧状に形成される。図３では、円弧相当縁線１３ｅの曲率半径は、半径相当縁線１３ｄの長さと同等に設定されている。 As shown in FIG. 3, the inflow hollow chamber 13 is formed in a fan-shaped base in a plan view. In FIG. 3, the hatched portion 13a is an inflow portion, and the non-hatched portion 13b is a remaining portion. In detail, the inflow hollow chamber 13 has two edge lines 13d in an opposing positional relationship corresponding to a fan-shaped radius part and an edge line 13e corresponding to a fan-shaped arc part when viewed in a plan view. It is formed in the shape. Hereinafter, the edge line 13d is referred to as a radius equivalent edge line 13d, and the edge line 13e is referred to as an arc equivalent edge line. The arc-equivalent edge line 13e is formed in an outwardly convex arc shape. In FIG. 3, the radius of curvature of the arc-equivalent edge line 13e is set to be equal to the length of the radius-equivalent edge line 13d.

円弧相当縁線１３ｅの一端には一方の半径相当縁線１３ｄの一端が接続され、円弧相当縁線１３ｅの他端には他方の半径相当縁線１３ｄの一端が接続されている。２つの半径相当縁線１３ｄ間の幅は、半径相当縁線１３ｄの一端側（円弧相当縁線１３ｅに接続された端部側）から他端側にいくにしたがって次第に小さくなっている。そして、２つの半径相当縁線１３ｄは他端側において互いに接続される。このとき、２つの半径相当縁線１３ｄの接続縁線１３ｆ（以下先端縁線という）が丸みを持った形状（円弧状）に設定される。また、各半径相当縁線１３ｄは、互いに同じ長さの直線状に形成される。流入部１３ａは、半径相当縁線１３ｄの両端のうち、２つの半径相当縁線１３ｄ間の幅が広い端部側（円弧相当縁線１３ｅ側）の２つの半径相当縁線１３ｄ間の部分に設定されている。 One end of one radius equivalent edge line 13d is connected to one end of the arc equivalent edge line 13e, and one end of the other radius equivalent edge line 13d is connected to the other end of the arc equivalent edge line 13e. The width between the two radius equivalent edge lines 13d gradually decreases from one end side (the end side connected to the arc equivalent edge line 13e) to the other end side of the radius equivalent edge line 13d. The two radius equivalent edge lines 13d are connected to each other on the other end side. At this time, the connection edge line 13f (hereinafter referred to as the front edge line) of the two radius equivalent edge lines 13d is set to have a round shape (arc shape). Further, each radius-equivalent edge line 13d is formed in a straight line having the same length. The inflow portion 13a is formed at the portion between the two radius equivalent edge lines 13d on the end side (the arc equivalent edge line 13e side) where the width between the two radius equivalent edge lines 13d is wide. Is set.

流入中空室１３の形状を別の表現であらわすと、流入中空室１３を平面視で見たときの面内方向の直線のうち、流入中空室１３の縁線１３ｄ、１３ｅと弁開口１０の縁線との両交点１４の間の中点１５を通り、両交点１４を通る直線Ｌ３に直角な直線Ｌ４を中心線とする。流入中空室１３は、その中心線Ｌ４に沿って流入部１３ａから離れるにしたがって中心線Ｌ４に直角な方向における幅が次第に小さくなる形状に形成されている。このように、流入部１３ａにおける幅（中心線Ｌ４に直角な方向における幅）が、残余部１３ｂにおける幅よりも大きくなっている。 When the shape of the inflow hollow chamber 13 is expressed by another expression, of the straight lines in the in-plane direction when the inflow hollow chamber 13 is viewed in plan view, the edge lines 13d and 13e of the inflow hollow chamber 13 and the edge of the valve opening 10 A straight line L4 that passes through the midpoint 15 between both intersections 14 with the line and is perpendicular to the straight line L3 that passes through both intersections 14 is taken as a center line. The inflow hollow chamber 13 is formed in a shape in which the width in the direction perpendicular to the center line L4 gradually decreases as the distance from the inflow portion 13a increases along the center line L4. Thus, the width at the inflow portion 13a (the width in the direction perpendicular to the center line L4) is larger than the width at the remaining portion 13b.

図２に示すように、残余部１３ｂの底面１３ｃには、底面１３ｃと、噴孔プレート８（平面部８ｄ）の表面８ｂとの間を貫通する噴孔１１が形成されている。このように、噴孔１１は、弁開口１０に対して半径方向にずれた位置で流入中空室１３（残余部１３ｂ）に繋がっている。噴孔１１は、噴射弁１の中心軸線Ｌ１を中心とした円周方向に１つ又は複数形成されている。本実施形態では、１つの流入中空室１３当たりに１つの噴孔１１が形成されている（図３参照）。つまり、流入中空室１３は、中心軸線Ｌ１を中心とした円周方向に、噴孔１１の個数分形成されている。噴孔１１は、噴孔軸線Ｌ２（図２参照）と噴射弁１の中心軸線Ｌ１とが平行となるよう形成されたとしても良いし、中心軸線Ｌ１に対して噴孔軸線Ｌ２が斜めの角度となるよう形成されたとしても良い。 As shown in FIG. 2, the bottom surface 13c of the remaining portion 13b is formed with a nozzle hole 11 penetrating between the bottom surface 13c and the surface 8b of the nozzle hole plate 8 (plane portion 8d). Thus, the nozzle hole 11 is connected to the inflow hollow chamber 13 (residual portion 13b) at a position shifted in the radial direction with respect to the valve opening 10. One or more injection holes 11 are formed in the circumferential direction around the central axis L1 of the injection valve 1. In the present embodiment, one injection hole 11 is formed per one inflow hollow chamber 13 (see FIG. 3). That is, the inflow hollow chambers 13 are formed by the number of the nozzle holes 11 in the circumferential direction around the central axis L1. The injection hole 11 may be formed such that the injection hole axis L2 (see FIG. 2) and the central axis L1 of the injection valve 1 are parallel to each other, and the injection hole axis L2 is at an oblique angle with respect to the central axis L1. It may be formed as follows.

また、図３に示すように、噴孔１１は、噴孔中心Ｏが中心線Ｌ４上に位置するよう形成されている。言い換えると、噴孔１１は、２つの半径相当縁線１３ｄに対して等距離となる位置に形成されている。さらに、噴孔１１は、噴孔１１への尿素水の流れ込みを１方向に集中させるという観点では、できるだけ先端縁線１３ｆに近い位置に形成されるのが好ましい。図３では、噴孔１１は、円弧相当縁線１３ｅよりも先端縁線１３ｆに寄った位置に形成されている。 As shown in FIG. 3, the nozzle hole 11 is formed such that the nozzle hole center O is positioned on the center line L4. In other words, the nozzle hole 11 is formed at a position that is equidistant from the two radius equivalent edge lines 13d. Furthermore, the nozzle hole 11 is preferably formed at a position as close to the tip edge line 13f as possible from the viewpoint of concentrating the flow of urea water into the nozzle hole 11 in one direction. In FIG. 3, the nozzle hole 11 is formed at a position closer to the tip edge line 13f than the arc-equivalent edge line 13e.

弁開口１０と噴孔１１との間に流入中空室１３を介在させ、噴孔１１が弁開口１０に対して半径方向にずれた位置に形成されることで、噴孔１１から噴射される尿素水噴霧を微粒化させることができる。すなわち、ニードル５が弁座４から離座する開弁時では、弁開口１０から流入中空室１３に流入した尿素水は、流入部１３ａの位置で半径方向に流れ方向を変え、その後、噴孔１１の位置で噴孔１１内に流れ込むよう流れ方向を変える。つまり、尿素水のＳ字型の流れを得ることができる。これにより、噴孔１１内において尿素水の流体形状が三日月状に変形されることで、尿素水噴霧の微粒化を促進できる。 Urea injected from the nozzle hole 11 by interposing the inflow hollow chamber 13 between the valve opening 10 and the nozzle hole 11 and forming the nozzle hole 11 at a position shifted in the radial direction with respect to the valve opening 10. Water spray can be atomized. That is, when the needle 5 is opened from the valve seat 4, the urea water flowing into the inflow hollow chamber 13 from the valve opening 10 changes the flow direction in the radial direction at the position of the inflow portion 13 a, and then the injection hole The flow direction is changed so as to flow into the nozzle hole 11 at the position 11. That is, an S-shaped flow of urea water can be obtained. Thereby, the atomization of urea water spray can be accelerated | stimulated because the fluid shape of urea water deform | transforms into the crescent moon in the nozzle hole 11. FIG.

さらに、流入中空室１３は扇型ベースに形成されているので、図４の右図に示すように、流入部１３ａから流入した尿素水の流れを噴孔１１の方向に集中させることができる。言い換えると、先端縁線１３ｆ側に尿素水が回り込んだ後、噴孔１１に流れ込むのを抑制できる。その結果、図５に示すように、噴孔１１から噴射された尿素水噴霧が必要以上に広がってしまうのを抑制でき、噴孔プレート８の表面８ｂに噴霧が付着して、尿素水由来の析出物が析出してしまうのを抑制できる。つまり、耐尿素析出性を向上できる。 Furthermore, since the inflow hollow chamber 13 is formed in a fan-shaped base, the flow of urea water flowing in from the inflow portion 13a can be concentrated in the direction of the nozzle hole 11 as shown in the right diagram of FIG. In other words, it is possible to suppress the urea water from flowing into the nozzle hole 11 after the urea water has entered the tip edge line 13f side. As a result, as shown in FIG. 5, it is possible to prevent the urea water spray injected from the nozzle hole 11 from spreading more than necessary, and the spray adheres to the surface 8 b of the nozzle hole plate 8, resulting in urea water-derived It can suppress that a deposit precipitates. That is, urea precipitation resistance can be improved.

また、２つの半径相当縁線１３ｄ間の角度θ（中心角）を大きくし、又は半径相当縁線１３ｄを長くすることで、流入部１３ａの面積を容易に大きくすることができる。流入部１３ａの面積が大きくなることで、流入部１３ａで尿素水の流れが絞られてしまうのを抑制でき、尿素水の流量精度の悪化を抑制つまり尿素水の噴射量のばらつきを抑制できる。また、流入部１３ａの面積を大きくしたとしても、噴孔１１と半径相当縁線１３ｄとの間の距離が必要以上に大きくなってしまうのを抑制でき、その結果、耐尿素析出性が低下するのを抑制できる。このように、扇型ベースの流入中空室１３を採用することで、噴霧の微粒化、流量精度の確保及び耐尿素析出性の確保を両立させることができる。 Moreover, the area of the inflow part 13a can be easily enlarged by enlarging the angle (theta) (center angle) between the two radius equivalent edge lines 13d, or lengthening the radius equivalent edge line 13d. By increasing the area of the inflow portion 13a, it is possible to suppress the flow of the urea water from being narrowed at the inflow portion 13a, and to suppress the deterioration of the flow rate accuracy of the urea water, that is, to suppress the variation in the injection amount of the urea water. Moreover, even if the area of the inflow portion 13a is increased, it is possible to suppress the distance between the nozzle hole 11 and the radius equivalent edge line 13d from being increased more than necessary, and as a result, the urea precipitation resistance is reduced. Can be suppressed. Thus, by adopting the fan-shaped base inflow hollow chamber 13, it is possible to achieve both atomization of the spray, ensuring of the flow rate accuracy and ensuring of urea precipitation resistance.

これに対して、図４の左図のように円形ベースの流入中空室２０の場合には、尿素水を一方向から噴孔１１に流れ込ませようとすると、流入中空室２０の径を小さくする必要がある。この場合、流入部２０ａの面積が小さくなってしまい、流入部２０ａにて尿素水の流れが絞られる結果、流量精度の悪化につながる。図４の真ん中の図に示すように、径を大きくした円形ベースの流入中空室２１を採用した場合には、流入部２１ａの面積を大きくできるものの、噴孔１１回りの全方向から尿素水が噴孔１１に流れ込む。その結果、尿素水噴霧が膜状に形成されて、図６に示すように、尿素水噴霧が必要以上に広がってしまう。そして、尿素水噴霧が噴孔プレートの表面に飛び散ることで、表面に尿素水が付着しやすく、尿素水由来の析出物が生じやすくなる。つまり、耐尿素析出性が悪化する。 On the other hand, in the case of the circular base inflow hollow chamber 20 as shown in the left diagram of FIG. 4, the diameter of the inflow hollow chamber 20 is reduced when urea water is allowed to flow into the injection hole 11 from one direction. There is a need. In this case, the area of the inflow portion 20a is reduced, and the flow of urea water is reduced in the inflow portion 20a, resulting in deterioration in flow rate accuracy. As shown in the middle diagram of FIG. 4, when a circular base inflow hollow chamber 21 having a large diameter is adopted, the area of the inflow portion 21 a can be increased, but urea water is generated from all directions around the nozzle hole 11. It flows into the nozzle hole 11. As a result, the urea water spray is formed in a film shape, and the urea water spray spreads more than necessary as shown in FIG. And since urea water spray is scattered on the surface of a nozzle hole plate, urea water tends to adhere to the surface and it becomes easy to produce the precipitate derived from urea water. That is, urea precipitation resistance deteriorates.

扇型ベースの流入中空室１３の形状についてさらに言及する。図７は、噴孔１１の面積Ｓ１（噴孔軸線に直交する平面で噴孔１１を切ったときの断面積）と流入部１３ａの平面視での面積Ｓ２との比Ｓ２／Ｓ１をいくつか変化させたときの、尿素水噴射量のずれ量（ばらつき）を示している。図７に示すように、面積比が小さいとばらつきが大きくなっているのに対し、面積比が大きいとばらつきが小さくなる。このことから、流入部１３ａの面積を大きくすることで、流量精度の悪化を抑制できるといえる。 The shape of the fan-shaped base inflow hollow chamber 13 will be further described. FIG. 7 shows some ratios S2 / S1 between the area S1 of the nozzle hole 11 (cross-sectional area when the nozzle hole 11 is cut in a plane perpendicular to the axis of the nozzle hole) and the area S2 in plan view of the inflow portion 13a. The deviation amount (variation) of the urea water injection amount when changed is shown. As shown in FIG. 7, the variation is large when the area ratio is small, whereas the variation is small when the area ratio is large. From this, it can be said that the deterioration of the flow rate accuracy can be suppressed by increasing the area of the inflow portion 13a.

図８は、２つの半径相当縁線１３ｄ間の角度（図９参照）と、各半径相当縁線１３ｄと噴孔１１との間の長さｄ１、ｄ２（図９参照）の和（噴孔壁面長さの和）との関係を示している。図８に示すように、角度と噴孔壁面長さの和とは相関しており、角度が大きくなるに比例して、噴孔壁面長さの和も大きくなる。噴孔壁面長さの和が大きすぎてしまうと、噴孔に一方向から尿素水の流れ込みが発生する限界を超えてしまい、耐尿素析出性が悪化する。したがって、噴孔壁面長さの和が大きくなりすぎないように、半径相当縁線１３ｄ間の角度を設定する必要がある。 FIG. 8 shows the sum of the angle (see FIG. 9) between the two radius equivalent edge lines 13d (see FIG. 9) and the lengths d1 and d2 (see FIG. 9) between the radius equivalent edge lines 13d and the nozzle holes 11 (injection hole). The sum of the wall length). As shown in FIG. 8, the angle and the sum of the nozzle hole wall lengths are correlated, and the sum of the nozzle hole wall lengths increases as the angle increases. If the sum of the wall lengths of the nozzle holes is too large, it exceeds the limit at which urea water flows into the nozzle holes from one direction, and urea precipitation resistance deteriorates. Therefore, it is necessary to set the angle between the radius equivalent edge lines 13d so that the sum of the nozzle hole wall lengths does not become too large.

以上、本実施形態によれば、流入中空室の形状を扇型ベースとしたので、噴霧の微粒化、流量精度の確保及び耐尿素析出性の確保を両立させることができる。また、図３に示すように、噴孔１１の中心Ｏが、流入中空室１３の中心線Ｌ４上に位置するので、噴孔１１と半径相当縁線１３ｄとの間の距離が大きくなってしまうのを抑制でき、噴孔１１に一方向から尿素水を流れ込ませ易くできる。 As described above, according to this embodiment, since the shape of the inflow hollow chamber is a fan-shaped base, it is possible to achieve both atomization of spray, ensuring of flow rate accuracy and ensuring of urea precipitation resistance. As shown in FIG. 3, since the center O of the injection hole 11 is located on the center line L4 of the inflow hollow chamber 13, the distance between the injection hole 11 and the radius equivalent edge line 13d is increased. Can be suppressed, and urea water can be easily flowed into the nozzle hole 11 from one direction.

なお、本発明は上記実施形態に限定されるものではなく、特許請求の範囲の記載を逸脱しない限度で種々の変更が可能である。例えば、図１０のように、１つの流入中空室１３当たりに複数（図１０では２つ）の噴孔１１が形成されたとしても良い。また、円弧相当縁線１３ｅの曲率はどのような曲率でも良く、図１１に示すように直線であっても良いし、図１２に示すように図３よりも曲率を小さくしても良いし、図１３に示すように図３よりも曲率を大きくしても良い。 In addition, this invention is not limited to the said embodiment, A various change is possible to the limit which does not deviate from description of a claim. For example, as shown in FIG. 10, a plurality of (two in FIG. 10) injection holes 11 may be formed per one inflow hollow chamber 13. Further, the curvature of the arc-corresponding edge line 13e may be any curvature, may be a straight line as shown in FIG. 11, or may have a curvature smaller than that of FIG. 3 as shown in FIG. As shown in FIG. 13, the curvature may be larger than that in FIG.

また、図１４に示すように、流入中空室１３の先端縁線１３ｆにさらに近い位置に噴孔１１が形成されたとしても良い。また、半径相当縁線１３ｄは、図１５のように外側に凸の形状に形成されたとしても良いし、図１６のように内側に凸の形状に形成されたとしても良い。 Further, as shown in FIG. 14, the nozzle hole 11 may be formed at a position closer to the tip edge line 13 f of the inflow hollow chamber 13. Further, the radius equivalent edge line 13d may be formed in a convex shape outward as shown in FIG. 15, or may be formed in a convex shape inward as shown in FIG.

また、半径相当縁線間の角度θは、図１７のように図３よりも小さい角度であっても良いし、図１８のように大きい角度であっても良い。また、図１９のように流入中空室の先端１３ｆが尖っていても良いし、図２０のように平らにしても良い。図２０の場合には、流入中空室は平面視で台形に近い形状となる。また、図２１のように、流入中空室１３の中心線Ｌ４に対してずれた位置に噴孔１１が形成されたとしても良い。言い換えると、噴孔１１の中心を通り、噴射弁１の中心軸線Ｌ１（図１参照）に交差する直線Ｌ５と流入中空室の中心線Ｌ４とがずれていても良い。 Further, the angle θ between the radius equivalent edge lines may be smaller than that shown in FIG. 3 as shown in FIG. 17 or may be larger as shown in FIG. Moreover, the tip 13f of the inflow hollow chamber may be sharp as shown in FIG. 19, or may be flat as shown in FIG. In the case of FIG. 20, the inflow hollow chamber has a shape close to a trapezoid in plan view. Further, as shown in FIG. 21, the nozzle hole 11 may be formed at a position shifted from the center line L <b> 4 of the inflow hollow chamber 13. In other words, the straight line L5 passing through the center of the injection hole 11 and intersecting the central axis L1 (see FIG. 1) of the injection valve 1 may be shifted from the center line L4 of the inflow hollow chamber.

また、図２２のように、流入中空室１３の側面１３ｇと底面１３ｃとの接続部にＲを形成しても良いし、図２３のように直角に形成しても良い。また、図２４のように、側面１３ｇを底面１３ｃに対して傾斜させても良い。 Further, as shown in FIG. 22, R may be formed at the connection portion between the side surface 13g and the bottom surface 13c of the inflow hollow chamber 13, or may be formed at a right angle as shown in FIG. Further, as shown in FIG. 24, the side surface 13g may be inclined with respect to the bottom surface 13c.

さらに、図２５〜図２８に示すように、ボディ端面２ａ側に流入中空室１６が形成されたとしても良い。なお、図２５〜図２８においては、上記実施形態と同様の部分には同一の符号を付している。図２７に示すように、流入中空室１６は、平面視で見て対向する位置関係にある２つの縁線１６ｄを有し、それら縁線１６ｄ間の幅が、縁線１６ｄの一端側から他端側にいくにしたがって次第に小さくなる形状に形成される。そして、縁線１６ｄの両端のうち縁線１６ｄ間の幅が広い方の端部側に、弁開口１０に面した流入部１６ａ（図２６参照）が設定される。噴孔１１は、流入中空室１６の残余部１６ｂ（図２７参照）に対面した位置に形成される。 Furthermore, as shown in FIGS. 25 to 28, the inflow hollow chamber 16 may be formed on the body end surface 2a side. In FIG. 25 to FIG. 28, the same reference numerals are given to the same parts as those in the above embodiment. As shown in FIG. 27, the inflow hollow chamber 16 has two edge lines 16d in a positional relationship facing each other when seen in a plan view, and the width between the edge lines 16d is different from one end side of the edge line 16d. It is formed in a shape that gradually decreases toward the end side. And the inflow part 16a (refer FIG. 26) which faced the valve opening 10 is set to the edge part side with the wider width | variety between the edge lines 16d among the both ends of the edge line 16d. The nozzle hole 11 is formed at a position facing the remaining portion 16 b (see FIG. 27) of the inflow hollow chamber 16.

言い換えると、流入中空室１６は、流入中空室１６の縁線１６ｄと弁開口１０の縁線との両交点１４間の中点１５を通り、両交点１４を通る直線Ｌ３に直角な直線Ｌ４に沿って流入部１６ａから離れるにしたがって、直線Ｌ４に直角な方向における幅が次第に小さくなる形状に形成される。一方、噴孔プレート８側には凹部が形成されていない（図２６参照）。これによっても、上記実施形態と同様の作用効果を奏する。 In other words, the inflow hollow chamber 16 passes through a midpoint 15 between both intersection points 14 between the edge line 16 d of the inflow hollow chamber 16 and the edge line of the valve opening 10, and is a straight line L4 perpendicular to the straight line L3 passing through both intersection points 14. As the distance from the inflow portion 16a increases, the width in the direction perpendicular to the straight line L4 is gradually reduced. On the other hand, no recess is formed on the nozzle hole plate 8 side (see FIG. 26). Also by this, there exists an effect similar to the said embodiment.

また、上記実施形態では、尿素水噴射弁に本発明を適用した例を説明したが、エンジン筒内や吸気ポートに燃料を噴射する燃料噴射弁や、排気管に尿素水以外の液体（燃料など）を噴射する噴射弁に本発明を適用しても良い。 In the above embodiment, an example in which the present invention is applied to a urea water injection valve has been described. However, a fuel injection valve that injects fuel into an engine cylinder or an intake port, or a liquid other than urea water (such as fuel) in an exhaust pipe. You may apply this invention to the injection valve which injects.

１噴射弁
２ノズルボディ
２ａボディ端面
３ニードル収容室
４弁座
５ニードル
８噴孔プレート
８ａプレート面
１０弁開口
１１噴孔
１３、１６流入中空室（凹部）
１３ａ、１６ａ流入部
１３ｂ、１６ｂ残余部
１３ｄ、１３ｅ、１６ｄ流入中空室の縁線
１４流入中空室の縁線と弁開口との交点
１５流入中空室の縁線と弁開口との両交点間の中点 DESCRIPTION OF SYMBOLS 1 Injection valve 2 Nozzle body 2a Body end surface 3 Needle accommodation chamber 4 Valve seat 5 Needle 8 Injection hole plate 8a Plate surface 10 Valve opening 11 Injection hole 13, 16 Inflow hollow chamber (recessed part)
13a, 16a Inflow part 13b, 16b Remaining part 13d, 13e, 16d Edge line of inflow hollow chamber 14 Intersection of edge line of inflow hollow chamber and valve opening 15 Between both intersections of edge line of inflow hollow chamber and valve opening Midpoint

Claims

A nozzle body (2) having a valve opening (10) formed at the tip and a needle housing chamber (3) having a valve seat (4) surrounding the valve opening;
A needle (5) provided movably between a valve closing position seated on the valve seat in the needle housing chamber and a valve opening position separated from the valve seat;
A nozzle hole plate (8) provided to cover the body end surface (2a), which is the tip surface of the nozzle body, and having at least one nozzle hole (11) formed thereon;
Recesses (13, 16) are formed in the plate surface (8a) in contact with the body end surface of the nozzle hole plate or the body end surface, and a part (13a, 16a) of the recess faces the valve opening. The remaining portions (13b, 16b) are covered with the plate surface and the body end surface that are not formed with the recesses,
The nozzle hole is connected to the recess at a position shifted in the radial direction with respect to the valve opening,
The concave portion has two edge lines (13d, 16d) that are opposed to each other when seen in a plan view, and the width between the two edge lines goes from one end side to the other end side of the edge line. Accordingly, the injection valve (1) is characterized in that the portion between the edge lines on the side of the wide end portion of the both ends of the edge line faces the valve opening.

A nozzle body (2) having a valve opening (10) formed at the tip and a needle housing chamber (3) having a valve seat (4) surrounding the valve opening;
A needle (5) provided movably between a valve closing position seated on the valve seat in the needle housing chamber and a valve opening position separated from the valve seat;
A nozzle hole plate (8) provided to cover the body end surface (2a), which is the tip surface of the nozzle body, and having at least one nozzle hole (11) formed thereon;
Recesses (13, 16) are formed in the plate surface (8a) in contact with the body end surface of the nozzle hole plate or the body end surface, and a part (13a, 16a) of the recess faces the valve opening. The remaining portions (13b, 16b) are covered with the plate surface and the body end surface that are not formed with the recesses,
The nozzle hole is connected to the recess at a position shifted in the radial direction with respect to the valve opening,
Of the concave portion, the portion facing the valve opening is an inflow portion, and among the straight lines in the in-plane direction when the concave portion is viewed in plan view, the edge lines (13d, 13e, 16d) of the concave portion and the valve opening A straight line (L4) perpendicular to the straight line (L3) passing through the middle point (15) between the two intersections (14) with the edge line and passing through the two intersections is used as the center line.
The injection valve (1), wherein the recess is formed in a shape in which a width in a direction perpendicular to the center line gradually decreases as the distance from the inflow portion increases along the center line.