JP2022068406A

JP2022068406A - Fluid control valve and EGR unit

Info

Publication number: JP2022068406A
Application number: JP2020177053A
Authority: JP
Inventors: 衛吉岡; Mamoru Yoshioka; 伸二河井; Shinji Kawai; 海翔曹; Haixiang Cao; 一真中島; Kazuma Nakajima
Original assignee: Aisan Industry Co Ltd
Current assignee: Aisan Industry Co Ltd
Priority date: 2020-10-22
Filing date: 2020-10-22
Publication date: 2022-05-10

Abstract

To prevent a valve element of a poppet type fluid control valve functioning as an internally opening type valve from being opened carelessly due to high negative pressure applied to a downstream side flow passage when the valve is fully closed.SOLUTION: An EGR valve 14 includes: a housing 41; a valve stem 42 in which a valve element 43 is provided; a stepping motor 44 reciprocating the valve stem 42; and a spring 45 energizing the valve element 43 and the valve stem 42 in the direction separating from the stepping motor 44. The valve element 43 includes a cylindrical outer shaft 52 extending from the valve element 43 along the valve stem 42 to enable contact with a lip seal 51 around the valve stem 42. The EGR valve includes the lip seal 51 sealing a space between the outer shaft 52 and the housing 41 when the outer shaft 52 reciprocates together with the valve element 43 and the valve stem 42. By sealing using the lip seal 51, an inner space 53 is provided in the housing 41. An upper end part of the outer shaft 52 faces the inner space 53, and an atmospheric passage 54 communicating the inner space 53 with the atmosphere is provided in the housing 41.SELECTED DRAWING: Figure 7

Description

この明細書に開示される技術は、流体の流量を制御するポペット式であって内開式の流体制御弁とそれを含むＥＧＲユニットに関する。 The techniques disclosed herein relate to poppet-type, internally open fluid control valves that control fluid flow rates and EGR units that include them.

従来、この種の技術として、例えば、下記の特許文献１に記載されるポペット式であって内開式のＥＧＲ弁が知られている。このＥＧＲ弁は、流路を有するハウジングと、流路に設けられた弁座と、弁座に対して着座可能に設けられた弁体と、一端部に弁体が設けられた弁軸と、弁軸を弁体と共に軸線方向へ往復動させるアクチュエータとを備える。流路は、弁座を境として上流側流路と下流側流路に分かれ、弁体は下流側流路にて弁座に着座可能に配置される。アクチュエータは雄ねじを有する駆動軸と、駆動軸を軸線方向へ往復動させるために雄ねじに螺合される雌ねじを有するロータと、ロータを回転させるコイルとを含む。雄ねじと雌ねじとの間には、駆動軸の軸線方向において所定のバックラッシが設けられる。駆動軸には、弁体を弁体を弁座に着座させる方向（閉弁方向）へ付勢する閉弁スプリングが設けられる。弁軸と駆動軸との間には、電磁クラッチが設けられる。 Conventionally, as this kind of technique, for example, a poppet-type and internally open-type EGR valve described in Patent Document 1 below is known. This EGR valve includes a housing having a flow path, a valve seat provided in the flow path, a valve body provided so as to be seated on the valve seat, and a valve shaft provided with a valve body at one end. It is provided with an actuator that reciprocates the valve shaft together with the valve body in the axial direction. The flow path is divided into an upstream side flow path and a downstream side flow path with the valve seat as a boundary, and the valve body is arranged so as to be seatable on the valve seat in the downstream side flow path. The actuator includes a drive shaft having a male screw, a rotor having a female screw screwed into the male screw to reciprocate the drive shaft in the axial direction, and a coil for rotating the rotor. A predetermined backlash is provided between the male and female threads in the axial direction of the drive shaft. The drive shaft is provided with a valve closing spring that urges the valve body in the direction in which the valve body is seated on the valve seat (valve closing direction). An electromagnetic clutch is provided between the valve shaft and the drive shaft.

ここで、内開式のＥＧＲ弁は、その開弁時に弁軸も弁座から離れるので、弁体を上流側流路にて弁座に着座可能に配置した外開式のＥＧＲ弁に比べ、次のようなメリットがある。すなわち、弁体の外径を等しくした場合、内開式では、ＥＧＲガスの最大流量が外開式よりも増加する。そのため、内開式では、所定の最大流量を得るための弁体の外径を外開式よりも小さくすることができ、結果として、低流量域の流量分解能を向上させることができる。このようなメリットが得られることから、内開式のＥＧＲ弁の利用について要請が高まっている。 Here, since the valve shaft of the internally open type EGR valve is also separated from the valve seat when the valve is opened, the valve body is arranged so as to be seated on the valve seat in the upstream flow path, as compared with the externally open type EGR valve. It has the following merits. That is, when the outer diameters of the valve bodies are made equal, the maximum flow rate of EGR gas in the inwardly open type is higher than that in the outwardly open type. Therefore, in the inwardly open type, the outer diameter of the valve body for obtaining a predetermined maximum flow rate can be made smaller than in the outwardly open type, and as a result, the flow rate resolution in the low flow rate region can be improved. Since such merits can be obtained, there is an increasing demand for the use of an internally open EGR valve.

特開２０１０－２７５９４１号公報Japanese Unexamined Patent Publication No. 2010-275941

ところが、特許文献１に記載の内開式のＥＧＲ弁では、その全閉時には、閉弁スプリングの付勢力により駆動軸が閉弁方向へ押され、雄ねじのねじ山が雌ねじのねじ山に当たった状態で弁体が弁座に着座する。この状態で、雌ねじと雄ねじとの間には、駆動軸が開弁方向へ動き得るバックラッシ（隙間）が存在する。そのため、下流側流路にて弁体に高い吸気負圧が作用すると、弁体と弁軸を介して駆動軸へ開弁方向の力が作用し、バックラッシの分だけ雄ねじが移動し、弁体が微小に開弁してしまう。この結果、ＥＧＲガスが下流側流路へ漏れ、不要なＥＧＲガスが吸気通路へ流れてしまうおそれがある。 However, in the internally open type EGR valve described in Patent Document 1, when the valve is fully closed, the drive shaft is pushed in the valve closing direction by the urging force of the valve closing spring, and the thread of the male thread hits the thread of the female thread. The valve body sits on the valve seat in this state. In this state, there is a backlash (gap) between the female screw and the male screw so that the drive shaft can move in the valve opening direction. Therefore, when a high intake negative pressure acts on the valve body in the downstream flow path, a force in the valve opening direction acts on the drive shaft via the valve body and the valve shaft, and the male screw moves by the amount of backlash, and the valve body. Will open the valve slightly. As a result, the EGR gas may leak to the downstream flow path, and unnecessary EGR gas may flow to the intake passage.

上記問題の対応策として、閉弁スプリングの付勢力（張力）を、高い吸気負圧に対抗できる程度に増大させることが考えられる。しかし、この場合は、閉弁スプリングが大型化したり、雄ねじと雌ねじとの間で摩耗が増加したりするおそれがあるので好ましくない。 As a countermeasure to the above problem, it is conceivable to increase the urging force (tension) of the valve closing spring to the extent that it can withstand the high intake negative pressure. However, in this case, the valve closing spring may become large and the wear between the male and female threads may increase, which is not preferable.

この開示技術は、上記事情に鑑みてなされたものであって、その目的は、ポペット式であって内開式として機能する流体制御弁において、全閉時に下流側流路に作用する高負圧により弁体が不用意に開弁してしまうことを防止することにある。 This disclosed technique was made in view of the above circumstances, and its purpose is to be a poppet type fluid control valve that functions as an inwardly open type, and has a high negative pressure acting on the downstream flow path when fully closed. This is to prevent the valve body from being inadvertently opened.

上記目的を達成するために、請求項１に記載の技術は、ハウジングと、ハウジングに設けられ、一端部と他端部を含む弁軸と、弁軸の一端部に設けられる弁体と、弁軸の他端部に対応してハウジングに設けられ、弁軸を弁体と共に軸線方向へ往復動させるためのアクチュエータと、弁体は、軸線方向において先部と基部とを含むことと、弁軸は、弁体の基部からアクチュエータへ向けて伸びることと、弁体を弁軸と共にアクチュエータから遠ざかる方向へ付勢するためのスプリングとを備え、流体の流量を制御する流体制御弁において、弁体の基部又は弁軸に設けられ、弁体を弁軸と共にアクチュエータに近づける方向へ付勢するように弁体の基部の側に作用する圧力を低減させるための作用圧低減手段と、作用圧低減手段が弁体及び弁軸と共に往復動するときに作用圧低減手段とハウジングとの間をシールするためのシール部材と、作用圧低減手段とハウジングとの間をシール部材によりシールすることでハウジングの内側に区分される内側空間と、作用圧低減手段は一端部を含み、一端部が内側空間に面して配置されることと、内側空間を大気に連通させるためにハウジングに設けられる大気通路とを備えたことを趣旨とする。 In order to achieve the above object, the technique according to claim 1 is a housing, a valve shaft provided in the housing including one end and the other end, a valve body provided at one end of the valve shaft, and a valve. An actuator provided in the housing corresponding to the other end of the shaft for reciprocating the valve shaft together with the valve body in the axial direction, and the valve body including a tip portion and a base portion in the axial direction, and a valve shaft. Is a fluid control valve that controls the flow rate of the fluid by extending from the base of the valve body toward the actuator and urging the valve body together with the valve shaft in a direction away from the actuator. The working pressure reducing means and the working pressure reducing means provided on the base or the valve shaft and for reducing the pressure acting on the side of the base of the valve body so as to urge the valve body together with the valve shaft in the direction closer to the actuator are provided. A sealing member for sealing between the working pressure reducing means and the housing when reciprocating together with the valve body and the valve shaft, and a sealing member for sealing between the working pressure reducing means and the housing inside the housing. The inner space to be separated and the working pressure reducing means include one end, the one end is arranged facing the inner space, and the air passage provided in the housing for communicating the inner space with the atmosphere is provided. The purpose is that.

上記技術の構成において、流体制御弁は、流路と、流路に設けられた弁座とを有する相手部材に組み付けて使用される。この組み付け状態において、弁体が弁座に着座した全閉状態では、流路は、弁座を境としてアクチュエータから遠い上流側流路とアクチュエータに近い下流側流路に分けられる。この場合、下流側流路にて弁体が弁座に着座可能に配置される。ここで、流体制御弁の全閉状態において、弁体の先部の側には、上流側流路の圧力が作用し、弁体の基部の側には、下流側流路の圧力が作用する。そして、下流側流路に高負圧が作用し、上流側流路に正圧が作用した場合、弁体には、上流側流路の正圧と下流側流路の高負圧との圧力差が、弁体を弁座から離間させる方向に作用し、弁体が不用意に弁座から離間する（開弁する）おそれがある。この不用意な開弁を回避するために、従来は、スプリングの付勢力を増大させたり、全閉状態を保つためにアクチュエータを動作させたりすることが考えられる。この点、上記技術の構成によれば、弁体の基部又は弁軸に、弁体を弁軸と共にアクチュエータに近づける方向へ付勢するように弁体の基部の側に作用する圧力を低減させるための作用圧低減手段が設けられる。また、この作用圧低減手段の一端部が、シール部材により下流側流路と区分されるハウジングの内側空間に面して配置される。この内側空間は、大気通路を介して常に大気圧に保たれる。従って、弁体には、弁座に着座する方向（弁体をアクチュエータから遠ざける方向）へ作用圧低減手段を介して大気圧が作用するので、下流側流路にて弁体を弁座から離間させる方向（弁体をアクチュエータに近づける方向）へ高負圧が作用しても、作用圧低減手段に作用する大気圧の分だけ弁体の基部の側に作用する高負圧による付勢力が低減される。 In the configuration of the above technique, the fluid control valve is used by assembling to a mating member having a flow path and a valve seat provided in the flow path. In this assembled state, in the fully closed state in which the valve body is seated on the valve seat, the flow path is divided into an upstream side flow path far from the actuator and a downstream side flow path close to the actuator with the valve seat as a boundary. In this case, the valve body is arranged so as to be seatable on the valve seat in the downstream flow path. Here, in the fully closed state of the fluid control valve, the pressure of the upstream side flow path acts on the tip side of the valve body, and the pressure of the downstream side flow path acts on the base side of the valve body. .. When a high negative pressure acts on the downstream flow path and a positive pressure acts on the upstream side flow path, the pressure between the positive pressure of the upstream side flow path and the high negative pressure of the downstream side flow path acts on the valve body. The difference acts in the direction of separating the valve body from the valve seat, and the valve body may inadvertently separate from the valve seat (open the valve). In order to avoid this careless valve opening, conventionally, it is conceivable to increase the urging force of the spring or to operate the actuator in order to keep the fully closed state. In this regard, according to the configuration of the above technique, in order to reduce the pressure acting on the base of the valve body or the valve shaft on the side of the base of the valve body so as to urge the valve body together with the valve shaft in a direction toward the actuator. A means for reducing the working pressure of the above is provided. Further, one end of the working pressure reducing means is arranged so as to face the inner space of the housing which is separated from the downstream flow path by the sealing member. This inner space is always maintained at atmospheric pressure through the atmospheric passage. Therefore, atmospheric pressure acts on the valve body in the direction of seating on the valve seat (direction in which the valve body is moved away from the actuator) via the acting pressure reducing means, so that the valve body is separated from the valve seat in the downstream flow path. Even if a high negative pressure acts in the direction of making the valve body closer to the actuator, the urging force due to the high negative pressure acting on the base side of the valve body is reduced by the amount of the atmospheric pressure acting on the acting pressure reducing means. Will be done.

上記目的を達成するために、請求項２に記載の技術は、請求項１に記載の技術において、作用圧低減手段は、弁軸の周囲に設けられ、シール部材に接触可能な外周部を含み、弁体の基部から弁軸に沿って伸びる円筒状の外軸であることを趣旨とする。 In order to achieve the above object, the technique according to claim 2 is the technique according to claim 1, wherein the acting pressure reducing means is provided around the valve shaft and includes an outer peripheral portion that can come into contact with the seal member. The purpose is that it is a cylindrical outer shaft extending from the base of the valve body along the valve shaft.

上記技術の構成によれば、請求項１に記載の技術の作用に加え、弁体には、弁体が弁座に着座する方向へ、外軸を介して内側空間から大気圧が作用するので、下流側流路にて弁体を弁座から離間させる方向へ高負圧が作用しても、外軸に作用する大気圧の分だけ弁体の基部の側に作用する高負圧による付勢力が低減される。また、弁軸と外軸との間のスペースにスプリングの配置が可能になるので、スプリングが下流側流路に露出することがない。 According to the configuration of the above technique, in addition to the action of the technique according to claim 1, atmospheric pressure acts on the valve body from the inner space via the outer shaft in the direction in which the valve body sits on the valve seat. Even if a high negative pressure acts in the direction that separates the valve body from the valve seat in the downstream flow path, the high negative pressure that acts on the base side of the valve body by the amount of the atmospheric pressure acting on the outer shaft is applied. The power is reduced. Further, since the spring can be arranged in the space between the valve shaft and the outer shaft, the spring is not exposed to the downstream flow path.

上記目的を達成するために、請求項３に記載の技術は、請求項１に記載の技術において、作用圧低減手段は、弁軸上にて弁体から離れて設けられ、シール部材に接触可能な外周部と、弁体の基部に対向する他端部とを含み、内側空間を閉鎖する閉鎖部材であることを趣旨とする。 In order to achieve the above object, the technique according to claim 3 is the technique according to claim 1, wherein the acting pressure reducing means is provided on the valve shaft away from the valve body and can come into contact with the seal member. It is intended to be a closing member that closes the inner space, including the outer peripheral portion and the other end portion facing the base portion of the valve body.

上記技術の構成によれば、請求項１に記載の技術の作用に加え、閉鎖部材の一端部が内側空間に面するので、弁体には、弁体が弁座に着座する方向へ閉鎖部材を介して内側空間から大気圧が作用する。従って、下流側流路にて弁体を弁座から離間させる方向へ高負圧が作用しても、閉鎖部材に作用する大気圧の分だけ弁体の基部の側に作用する高負圧による付勢力が低減される。また、閉鎖部材の他端部が弁体の基部に対向することで下流側流路に面するので、下流側流路に作用する高負圧が、閉鎖部材を介して、弁体が弁座に着座する方向に作用する。従って、閉鎖部材に作用する高負圧の分だけ弁体を弁座から離間させる方向へ作用する高負圧による付勢力が低減される。 According to the configuration of the above technique, in addition to the operation of the technique according to claim 1, since one end of the closing member faces the inner space, the valve body has a closing member in the direction in which the valve body is seated on the valve seat. Atmospheric pressure acts from the inner space through. Therefore, even if a high negative pressure acts in the downstream flow path in the direction of separating the valve body from the valve seat, the high negative pressure acting on the base side of the valve body by the amount of the atmospheric pressure acting on the closing member causes. The urging force is reduced. Further, since the other end of the closing member faces the downstream flow path by facing the base of the valve body, the high negative pressure acting on the downstream flow path causes the valve body to sit on the valve seat via the closing member. It acts in the direction of sitting on. Therefore, the urging force due to the high negative pressure acting in the direction of separating the valve body from the valve seat is reduced by the amount of the high negative pressure acting on the closing member.

上記目的を達成するために、請求項４に記載の技術は、請求項２又は３に記載の技術において、外軸又は閉鎖部材は、外周部に、外径を拡大する拡径部を含み、拡径部の一端部が内側空間に面して配置され、他端部が弁体へ向いて配置されることを趣旨とする。 In order to achieve the above object, the technique according to claim 4 is the technique according to claim 2 or 3, wherein the outer shaft or the closing member includes an enlarged diameter portion having an outer diameter on the outer peripheral portion. It is intended that one end of the enlarged diameter portion is arranged facing the inner space and the other end portion is arranged facing the valve body.

上記技術の構成によれば、請求項２又は３に記載の技術の作用に加え、拡径部の他端部が弁体へ向いて配置されることで下流側流路に面するので、下流側流路に作用する高負圧が、拡径部の他端部に作用して弁体が弁座に着座する方向に付勢される。従って、その付勢力の分だけ弁体を弁座から離間させる方向へ作用する高負圧による付勢力が更に低減される。 According to the configuration of the above technique, in addition to the operation of the technique according to claim 2 or 3, the other end of the enlarged diameter portion is arranged toward the valve body so as to face the downstream flow path, so that it is downstream. The high negative pressure acting on the side flow path acts on the other end of the enlarged diameter portion and is urged in the direction in which the valve body is seated on the valve seat. Therefore, the urging force due to the high negative pressure acting in the direction of separating the valve body from the valve seat is further reduced by the amount of the urging force.

上記目的を達成するために、請求項５に記載の技術は、請求項１乃至４のいずれかに記載の技術において、ハウジングに設けられ、流体が流れる流路と、流路に設けられ、弁体の先部が着座又は離間する弁座とを更に備え、流路は、弁座を境としてアクチュエータから遠い上流側流路とアクチュエータに近い下流側流路に分かれ、下流側流路にて弁体が弁座に着座可能に配置されることを趣旨とする。 In order to achieve the above object, the technique according to claim 5 is provided in a housing, a flow path through which a fluid flows, and a valve provided in the flow path in the technique according to any one of claims 1 to 4. The front part of the body is further provided with a valve seat that is seated or separated, and the flow path is divided into an upstream side flow path far from the actuator and a downstream side flow path close to the actuator with the valve seat as a boundary, and a valve is provided in the downstream side flow path. The purpose is that the body is placed so that it can be seated on the valve seat.

上記技術の構成によれば、請求項１乃至４のいずれかに記載の技術の作用に加え、ハウジングに流路と弁座が一体に設けられるので、流体制御弁を流路と弁座を有する別の相手部材に組み付ける必要がない。 According to the configuration of the above technique, in addition to the operation of the technique according to any one of claims 1 to 4, since the flow path and the valve seat are integrally provided in the housing, the fluid control valve has the flow path and the valve seat. There is no need to assemble it to another mating member.

上記目的を達成するために、請求項６に記載の技術は、請求項１乃至５のいずれかに記載の技術において、流体はＥＧＲガスであり、流体制御弁は、ＥＧＲガスの流量を制御するＥＧＲ弁であることを趣旨とする。 In order to achieve the above object, the technique according to claim 6 is the technique according to any one of claims 1 to 5, wherein the fluid is EGR gas and the fluid control valve controls the flow rate of EGR gas. The purpose is to be an EGR valve.

上記技術の構成によれば、ＥＧＲ弁の全閉時に、その弁体につき請求項１乃至５のいずれかに記載の技術と同等の作用が得られる。 According to the above-mentioned technique, when the EGR valve is fully closed, the same operation as that of the technique according to any one of claims 1 to 5 can be obtained for the valve body.

上記目的を達成するために、請求項７に記載の技術は、請求項６に記載のＥＧＲ弁と、ＥＧＲガスを冷却するためのＥＧＲクーラとを備え、ＥＧＲクーラは、ＥＧＲガスが流入する入口と、ＥＧＲガスが流出する出口とを含み、ＥＧＲ弁は、ＥＧＲクーラの出口に対応してＥＧＲクーラと一体に設けられることを趣旨とする。 In order to achieve the above object, the technique according to claim 7 includes the EGR valve according to claim 6 and an EGR cooler for cooling the EGR gas, and the EGR cooler is an inlet through which the EGR gas flows. It is intended that the EGR valve is provided integrally with the EGR cooler corresponding to the outlet of the EGR cooler, including the outlet from which the EGR gas flows out.

上記技術の構成によれば、請求項６に記載の技術の作用に加え、ＥＧＲクーラの出口に対応してＥＧＲクーラと一体に設けられたＥＧＲ弁により内開式のポペット弁が構成されるので、開弁時には、下流側流路にて、ＥＧＲ弁の弁体及び弁軸が、弁座からアクチュエータに近づく方向へ離間することになる。 According to the configuration of the above technique, in addition to the operation of the technique according to claim 6, the inwardly open poppet valve is configured by the EGR valve provided integrally with the EGR cooler corresponding to the outlet of the EGR cooler. At the time of valve opening, the valve body and valve shaft of the EGR valve are separated from the valve seat in the direction approaching the actuator in the downstream flow path.

請求項１に記載の技術によれば、ポペット式であって内開式として機能する流体制御弁において、その全閉時に下流側流路に作用する高負圧により弁体が不用意に開弁することを防止することができる。 According to the technique according to claim 1, in a fluid control valve that is a poppet type and functions as an inwardly open type, the valve body carelessly opens due to a high negative pressure acting on the downstream flow path when the valve is fully closed. Can be prevented from doing so.

請求項２に記載の技術によれば、請求項１に記載の技術の効果に加え、弁体の周囲を簡素化することができ、下流側流路における流体の圧損を低減することができる。 According to the second aspect of the present invention, in addition to the effect of the technique according to the first aspect, the circumference of the valve body can be simplified and the pressure loss of the fluid in the downstream flow path can be reduced.

請求項３に記載の技術によれば、請求項１に記載の技術の効果に加え、流体制御弁の全閉時に、下流側流路に作用する高負圧により弁体が不用意に開弁することをより確実に防止することができる。 According to the technique according to claim 3, in addition to the effect of the technique according to claim 1, when the fluid control valve is fully closed, the valve body carelessly opens due to the high negative pressure acting on the downstream flow path. It is possible to prevent this from happening more reliably.

請求項４に記載の技術によれば、請求項２又は３に記載の技術の効果に加え、流体制御弁の全閉時に、下流側流路に作用する高い吸気負圧により弁体が不用意に開弁することをより確実に防止することができる。 According to the technique according to claim 4, in addition to the effect of the technique according to claim 2 or 3, the valve body is not prepared due to the high intake negative pressure acting on the downstream flow path when the fluid control valve is fully closed. It is possible to more reliably prevent the valve from opening.

請求項５に記載の技術によれば、請求項１乃至４のいずれかに記載の技術の効果に加え、流体制御弁それのみを流体の通路の任意の位置に接続するだけで、流体の流量制御も使用できるようになる。 According to the technique according to claim 5, in addition to the effect of the technique according to any one of claims 1 to 4, the fluid flow rate is only required to connect the fluid control valve itself to an arbitrary position in the fluid passage. Control will also be available.

請求項６に記載の技術によれば、ＥＧＲ弁の全閉時に、その弁体につき請求項１乃至５のいずれかに記載の技術と同等の効果を得ることができる。 According to the technique according to claim 6, when the EGR valve is fully closed, the same effect as that of the technique according to claim 1 to 5 can be obtained for the valve body.

請求項７に記載の技術によれば、請求項６に記載の技術の効果に加え、ＥＧＲクーラの出口におけるＥＧＲガスの圧損を低減することができ、ＥＧＲガスをＥＧＲクーラからＥＧＲ弁へ流れ易くすることができる。 According to the technique according to claim 7, in addition to the effect of the technique according to claim 6, the pressure loss of the EGR gas at the outlet of the EGR cooler can be reduced, and the EGR gas can easily flow from the EGR cooler to the EGR valve. can do.

第１実施形態に係り、エンジンシステムを示す概略構成図。A schematic configuration diagram showing an engine system according to the first embodiment. 第１実施形態に係り、ＥＧＲユニットの具体例を示す断面図。FIG. 6 is a cross-sectional view showing a specific example of the EGR unit according to the first embodiment. 第１実施形態に係り、図２の一点鎖線四角で囲った部分であって全閉に動作したＥＧＲ弁を示す断面図。FIG. 2 is a cross-sectional view showing an EGR valve which is a portion surrounded by a alternate long and short dash line square in FIG. 2 and operates in a fully closed state according to the first embodiment. 第１実施形態に係り、全閉に動作したＥＧＲ弁のみを示す断面図。FIG. 6 is a cross-sectional view showing only the EGR valve operated in the fully closed state according to the first embodiment. 第１実施形態に係り、図２の一点鎖線四角で囲った部分であって全開に動作したＥＧＲ弁を示す断面図。FIG. 2 is a cross-sectional view showing an EGR valve which is a portion surrounded by a alternate long and short dash line square in FIG. 2 and operates fully open according to the first embodiment. 第１実施形態に係り、全開に動作したＥＧＲ弁のみを示す断面図。FIG. 6 is a cross-sectional view showing only the EGR valve operated at full throttle according to the first embodiment. 第１実施形態に係り、図３に示す全閉に動作したＥＧＲ弁を簡略化して示す断面図。FIG. 3 is a simplified cross-sectional view showing the EGR valve operated in the fully closed state shown in FIG. 3 according to the first embodiment. 第２実施形態に係り、全閉に動作したＥＧＲ弁を示す図７に準ずる簡略化した断面図。FIG. 7 is a simplified cross-sectional view according to FIG. 7, showing an EGR valve operated in a fully closed state according to a second embodiment. 第３実施形態に係り、全閉に動作したＥＧＲ弁を示す図７に準ずる簡略化した断面図。FIG. 7 is a simplified cross-sectional view according to FIG. 7, showing an EGR valve operated in a fully closed state according to a third embodiment. 第４実施形態に係り、全閉に動作したＥＧＲ弁を示す断面図。FIG. 6 is a cross-sectional view showing an EGR valve operated in a fully closed state according to a fourth embodiment.

以下、流体制御弁及びＥＧＲユニットをガソリンエンジンシステムに具体化したいくつかの実施形態について説明する。 Hereinafter, some embodiments in which the fluid control valve and the EGR unit are embodied in a gasoline engine system will be described.

＜第１実施形態＞
先ず、第１実施形態について図面を参照して詳細に説明する。 <First Embodiment>
First, the first embodiment will be described in detail with reference to the drawings.

[エンジンシステムについて]
図１に、この実施形態のガソリンエンジンシステム（以下、単に「エンジンシステム」と言う。）を概略構成図により示す。自動車に搭載されたエンジンシステムは、複数の気筒を有するエンジン１を備える。このエンジン１は、４気筒、４サイクルのレシプロエンジンであり、ピストン及びクランクシャフト等の周知の構成を含む。エンジン１には、各気筒へ吸気を導入するための吸気通路２と、エンジン１の各気筒から排気を導出するための排気通路３が設けられる。 [About the engine system]
FIG. 1 shows a gasoline engine system of this embodiment (hereinafter, simply referred to as “engine system”) by a schematic configuration diagram. The engine system mounted on the automobile includes an engine 1 having a plurality of cylinders. The engine 1 is a 4-cylinder, 4-cycle reciprocating engine and includes well-known configurations such as a piston and a crankshaft. The engine 1 is provided with an intake passage 2 for introducing intake air into each cylinder and an exhaust passage 3 for deriving exhaust gas from each cylinder of the engine 1.

吸気通路２には、スロットル装置４及び吸気マニホールド５が設けられる。吸気マニホールド５は、吸気通路２の一部を構成する。排気通路３には、その上流側から順に排気マニホールド６及び触媒７が設けられる。触媒７には、排気を浄化するために、例えば、三元触媒が内蔵される。加えて、排気通路３と吸気通路２との間には、高圧ループタイプの排気還流装置（ＥＧＲ装置）１１が設けられる。 The intake passage 2 is provided with a throttle device 4 and an intake manifold 5. The intake manifold 5 constitutes a part of the intake passage 2. The exhaust manifold 6 and the catalyst 7 are provided in the exhaust passage 3 in order from the upstream side thereof. The catalyst 7 contains, for example, a three-way catalyst in order to purify the exhaust gas. In addition, a high-pressure loop type exhaust gas recirculation device (EGR device) 11 is provided between the exhaust passage 3 and the intake passage 2.

スロットル装置４は、吸気マニホールド５より上流の吸気通路２に配置され、運転者のアクセル操作に応じてバタフライ式のスロットル弁４ａを開度可変に開閉駆動させることで、吸気通路２を流れる吸気量を調節するようになっている。吸気マニホールド５は、主として樹脂材より構成され、エンジン１の直上流にて吸気通路２に配置される。吸気マニホールド５は、吸気が導入される一つのサージタンク５ａと、サージタンク５ａに導入される吸気をエンジン１の各気筒へ分配するためにサージタンク５ａから分岐した複数（４つ）の分岐管５ｂとを含む。 The throttle device 4 is arranged in the intake passage 2 upstream of the intake manifold 5, and by driving the butterfly type throttle valve 4a to open and close with a variable opening according to the accelerator operation of the driver, the amount of intake air flowing through the intake passage 2 Is designed to be adjusted. The intake manifold 5 is mainly composed of a resin material and is arranged in the intake passage 2 directly upstream of the engine 1. The intake manifold 5 includes one surge tank 5a into which intake air is introduced, and a plurality (four) branch pipes branched from the surge tank 5a in order to distribute the intake air introduced into the surge tank 5a to each cylinder of the engine 1. Includes 5b.

エンジン１には、各気筒に対応して燃料を噴射するための燃料噴射装置（図示略）が設けられる。燃料噴射装置は、燃料供給装置（図示略）から供給される燃料をエンジン１の各気筒へ噴射するように構成される。各気筒では、燃料噴射装置から噴射される燃料と吸気マニホールド５から導入される吸気とにより可燃混合気が形成される。 The engine 1 is provided with a fuel injection device (not shown) for injecting fuel corresponding to each cylinder. The fuel injection device is configured to inject fuel supplied from a fuel supply device (not shown) into each cylinder of the engine 1. In each cylinder, a combustible air-fuel mixture is formed by the fuel injected from the fuel injection device and the intake air introduced from the intake manifold 5.

また、エンジン１には、各気筒に対応して点火装置（図示略）が設けられる。点火装置は、各気筒で可燃混合気に点火するように構成される。各気筒内の可燃混合気は、点火装置の点火動作により爆発・燃焼し、燃焼後の排気は、各気筒から排気マニホールド６及び触媒７を経て外部へ排出される。このとき、各気筒でピストン（図示略）が上下運動し、クランクシャフト（図示略）が回転することにより、エンジン１に動力が得られる。 Further, the engine 1 is provided with an ignition device (not shown) corresponding to each cylinder. The igniter is configured to ignite the combustible mixture in each cylinder. The combustible air-fuel mixture in each cylinder explodes and burns due to the ignition operation of the ignition device, and the exhaust gas after combustion is discharged from each cylinder to the outside via the exhaust manifold 6 and the catalyst 7. At this time, the piston (not shown) moves up and down in each cylinder, and the crankshaft (not shown) rotates to obtain power to the engine 1.

[ＥＧＲ装置について]
この実施形態のＥＧＲ装置１１は、エンジン１の各気筒から排気通路３へ排出される排気の一部を排気還流ガス（ＥＧＲガス）として吸気通路２へ流してエンジン１の各気筒へ還流させるように構成される。すなわち、ＥＧＲ装置１１は、排気還流通路（ＥＧＲ通路）１２と、ＥＧＲ通路１２を流れるＥＧＲガスを冷却するための排気還流クーラ（ＥＧＲクーラ）１３と、ＥＧＲ通路１２を流れるＥＧＲガスの流量を制御（調節）するための排気還流弁（ＥＧＲ弁）１４と、ＥＧＲ通路１２を流れるＥＧＲガスをエンジン１の各気筒へ分配するために、吸気マニホールド５の各分岐管５ｂへＥＧＲガスを分配するための排気還流ガス分配器（ＥＧＲガス分配器）１５とを備える。ＥＧＲ通路１２は、入口１２ａと出口１２ｂを含む。その入口１２ａは触媒７より上流の排気通路３に接続され、その出口１２ｂはＥＧＲガス分配器１５に接続される。ＥＧＲガス分配器１５は、ＥＧＲ通路１２の終段を構成する。ＥＧＲ通路１２において、ＥＧＲ弁１４は、ＥＧＲクーラ１３より下流に設けられ、ＥＧＲガス分配器１５は、ＥＧＲ弁１４より下流に設けられる。この実施形態で、ＥＧＲクーラ１３は、ＥＧＲガスが流入する入口２３（図２参照）と、ＥＧＲガスが流出する出口２４（図２参照）とを有する。ＥＧＲ弁１４は、ＥＧＲクーラ１３の出口２４に対応してＥＧＲクーラ１３と一体に設けられる。ＥＧＲクーラ１３とＥＧＲ弁１４とによりＥＧＲユニット１７が構成される。この実施形態で、ＥＧＲ弁１４は、この開示技術の流体制御弁の一例に相当し、ＥＧＲガスはＥＧＲ弁１４が流量を制御する流体の一例に相当する。 [About EGR equipment]
The EGR device 11 of this embodiment causes a part of the exhaust gas discharged from each cylinder of the engine 1 to the exhaust passage 3 to flow as an exhaust gas recirculation gas (EGR gas) to the intake passage 2 and return to each cylinder of the engine 1. It is composed of. That is, the EGR device 11 controls the exhaust gas recirculation passage (EGR passage) 12, the exhaust gas recirculation cooler (EGR cooler) 13 for cooling the EGR gas flowing through the EGR passage 12, and the flow rate of the EGR gas flowing through the EGR passage 12. To distribute the EGR gas to each branch pipe 5b of the intake manifold 5 in order to distribute the exhaust gas recirculation valve (EGR valve) 14 for (adjustment) and the EGR gas flowing through the EGR passage 12 to each cylinder of the engine 1. The exhaust gas recirculation gas distributor (EGR gas distributor) 15 is provided. The EGR passage 12 includes an inlet 12a and an outlet 12b. The inlet 12a is connected to the exhaust passage 3 upstream of the catalyst 7, and the outlet 12b is connected to the EGR gas distributor 15. The EGR gas distributor 15 constitutes the final stage of the EGR passage 12. In the EGR passage 12, the EGR valve 14 is provided downstream from the EGR cooler 13, and the EGR gas distributor 15 is provided downstream from the EGR valve 14. In this embodiment, the EGR cooler 13 has an inlet 23 into which the EGR gas flows in (see FIG. 2) and an outlet 24 into which the EGR gas flows out (see FIG. 2). The EGR valve 14 is provided integrally with the EGR cooler 13 corresponding to the outlet 24 of the EGR cooler 13. The EGR unit 17 is composed of the EGR cooler 13 and the EGR valve 14. In this embodiment, the EGR valve 14 corresponds to an example of a fluid control valve of the disclosed technique, and the EGR gas corresponds to an example of a fluid in which the EGR valve 14 controls the flow rate.

このＥＧＲ装置１１では、ＥＧＲ弁１４が開弁することにより、排気通路３を流れる排気の一部がＥＧＲガスとしてＥＧＲ通路１２を流れ、ＥＧＲクーラ１３で冷却され、更にＥＧＲ弁１４で流量が制御され、ＥＧＲガス分配器１５を介して吸気マニホールド５の各分岐管５ｂへ分配され、更にエンジン１の各気筒へ分配されて還流される。 In this EGR device 11, when the EGR valve 14 is opened, a part of the exhaust gas flowing through the exhaust passage 3 flows through the EGR passage 12 as EGR gas, is cooled by the EGR cooler 13, and the flow rate is further controlled by the EGR valve 14. Then, it is distributed to each branch pipe 5b of the intake manifold 5 via the EGR gas distributor 15, and further distributed to each cylinder of the engine 1 to be circulated.

［ＥＧＲユニットについて］
図２に、ＥＧＲユニット１７の具体例を断面図により示す。図２において、ＥＧＲクーラ１３は、ケーシング２１と、ケーシング２１の中に設けられる熱交換器２２と、ケーシング２１にＥＧＲガスを導入するための入口２３と、ケーシング２１からＥＧＲガスを導出するための出口２４とを含む。この実施形態において、ＥＧＲクーラ１３は、ＥＧＲ通路１２において、出口２４が入口２３よりも垂直方向において高い位置に配置されるように斜めに配置される。従って、このＥＧＲクーラ１３では、ＥＧＲガスが入口２３から出口２４へ向けて斜め上方へ向けて流れる。 [About EGR unit]
FIG. 2 shows a specific example of the EGR unit 17 with a cross-sectional view. In FIG. 2, the EGR cooler 13 has a casing 21, a heat exchanger 22 provided in the casing 21, an inlet 23 for introducing EGR gas into the casing 21, and an EGR gas for deriving from the casing 21. Includes exit 24. In this embodiment, the EGR cooler 13 is arranged obliquely in the EGR passage 12 so that the outlet 24 is located higher in the vertical direction than the inlet 23. Therefore, in this EGR cooler 13, EGR gas flows diagonally upward from the inlet 23 toward the outlet 24.

ケーシング２１は、熱交換器２２が設けられる本体部２１ａと、本体部２１ａから入口２３までの間の導入部２１ｂと、本体部２１ａから出口２４までの間の導出部２１ｃと、導出部２１ｃより下流にてＥＧＲ弁１４が組み付けられる組付部２１ｄとを含む。導入部２１ｂは、その内部に導入空間２５を有する。導出部２１ｃは、その内部に導出空間２６を有する。熱交換器２２は、冷却水が流れる水通路３１と、水通路３１の中に配置され、ＥＧＲガスが流れるガス通路３２とを含む。水通路３１は、扁平形状をなし互いに平行に配置された複数の小水通路３１ａを含む。ガス通路３２は、小水通路３１ａの間にて扁平形状をなし互いに平行に配置された複数の小ガス通路３２ａを含む。各小水通路３１ａの外壁には、多数のフィン３３が設けられる。各小水通路３１ａの軸方向両端は封鎖される。本体部２１ａには、水通路３１に冷却水を取り入れるための取入口３４と、水通路３１から冷却水を取り出すための取出口３５が設けられる。取入口３４から取り入れられた冷却水は、各小水通路３１ａを流れて取出口３５から取り出される。各小ガス通路３２ａの軸方向両端は開口しており、それぞれ導入空間２５及び導出空間２６に連通する。従って、この入口２３から導入空間２５に導入されたＥＧＲガスは、各小ガス通路３２ａを通過して導出空間２６へ流れる。各小ガス通路３２ａを通過するＥＧＲガスは、小水通路３１ａとの間で熱交換が行われ、冷却される。 The casing 21 is provided from the main body 21a in which the heat exchanger 22 is provided, the introduction portion 21b between the main body 21a and the inlet 23, the lead-out portion 21c between the main body 21a and the outlet 24, and the lead-out portion 21c. Includes an assembly portion 21d to which the EGR valve 14 is assembled downstream. The introduction unit 21b has an introduction space 25 inside thereof. The derivation unit 21c has a derivation space 26 inside thereof. The heat exchanger 22 includes a water passage 31 through which cooling water flows and a gas passage 32 arranged in the water passage 31 through which EGR gas flows. The water passage 31 includes a plurality of small water passages 31a having a flat shape and arranged in parallel with each other. The gas passage 32 includes a plurality of small gas passages 32a having a flat shape and arranged in parallel with each other between the small water passages 31a. A large number of fins 33 are provided on the outer wall of each small water passage 31a. Both ends of each small water passage 31a in the axial direction are closed. The main body 21a is provided with an intake port 34 for taking in the cooling water into the water passage 31 and an outlet 35 for taking out the cooling water from the water passage 31. The cooling water taken in from the intake port 34 flows through each small water passage 31a and is taken out from the intake port 35. Both ends of each small gas passage 32a in the axial direction are open and communicate with the introduction space 25 and the lead-out space 26, respectively. Therefore, the EGR gas introduced into the introduction space 25 from the inlet 23 passes through each small gas passage 32a and flows to the lead-out space 26. The EGR gas passing through each small gas passage 32a undergoes heat exchange with the small water passage 31a and is cooled.

ケーシング２１の組付部２１ｄには、ＥＧＲクーラ１３の出口２４に連通する組付孔２８と流路２９が設けられる。流路２９の一端には出口２９ａが設けられる。組付孔２８には、ＥＧＲ弁１４が組み付けられ、出口２４には、組み付けられたＥＧＲ弁１４の弁体４３が着座（閉弁）又は離間（開弁）する弁座３０が設けられる。この実施形態では、組付部２１ｄにＥＧＲ弁１４が組み付けられた状態で、ポペット式であって内開式のＥＧＲ弁が構成される。そして、ＥＧＲ弁１４の弁体４３が弁座３０から離間することで、ＥＧＲガスがＥＧＲクーラ１３の出口２４から流路２９へ流れ、出口２９ａから導出される。 The assembly portion 21d of the casing 21 is provided with an assembly hole 28 and a flow path 29 that communicate with the outlet 24 of the EGR cooler 13. An outlet 29a is provided at one end of the flow path 29. The EGR valve 14 is assembled in the assembly hole 28, and the outlet 24 is provided with a valve seat 30 in which the valve body 43 of the assembled EGR valve 14 is seated (closed) or separated (opened). In this embodiment, a poppet-type and internally open-type EGR valve is configured with the EGR valve 14 assembled to the assembly portion 21d. Then, when the valve body 43 of the EGR valve 14 is separated from the valve seat 30, the EGR gas flows from the outlet 24 of the EGR cooler 13 to the flow path 29 and is led out from the outlet 29a.

［ＥＧＲ弁の構成について］
次に、ＥＧＲ弁１４の構成について説明する。図３に、図２の一点鎖線四角Ｓ１で囲った部分であって全閉に動作したＥＧＲ弁１４を断面図により示す。図４に、全閉に動作したＥＧＲ弁１４のみを断面図により示す。図５に、図２の一点鎖線四角Ｓ１で囲った部分であって全開に動作したＥＧＲ弁１４を断面図により示す。図６に、全開に動作したＥＧＲ弁１４のみを断面図により示す。図７に、図３に示す全閉に動作したＥＧＲ弁１４を簡略化した断面図により示す。 [About the configuration of the EGR valve]
Next, the configuration of the EGR valve 14 will be described. FIG. 3 is a cross-sectional view showing an EGR valve 14 which is a portion surrounded by the alternate long and short dash line square S1 in FIG. 2 and operated to be fully closed. FIG. 4 shows a cross-sectional view of only the EGR valve 14 that has been fully closed. FIG. 5 is a cross-sectional view showing an EGR valve 14 which is a portion surrounded by the alternate long and short dash line square S1 in FIG. 2 and operates fully open. FIG. 6 shows a cross-sectional view of only the EGR valve 14 that has been fully opened. FIG. 7 shows a simplified cross-sectional view of the fully closed EGR valve 14 shown in FIG.

図３～図６に示すように、ＥＧＲ弁１４は、ハウジング４１と、ハウジング４１に設けられ、下端部（一端部）と上端部（他端部）を含む弁軸４２と、弁軸４２の下端部に設けられる弁体４３と、弁軸４２の上端部に対応してハウジング４１に設けられ、弁軸４２を弁体４３と共に軸線方向へ往復動させるためのステップモータ４４と、弁体４３を弁軸４２と共にステップモータ４４から遠ざかる方向へ付勢するためのスプリング４５とを含む。弁軸４２は、ハウジング４１の中心を貫通して配置され、上端部に雄ねじ４６が設けられる。ステップモータ４４は、この開示技術のアクチュエータの一例に相当する。 As shown in FIGS. 3 to 6, the EGR valve 14 is provided on the housing 41, the valve shaft 42 including the lower end portion (one end portion) and the upper end portion (the other end portion), and the valve shaft 42. A valve body 43 provided at the lower end portion, a step motor 44 provided in the housing 41 corresponding to the upper end portion of the valve shaft 42, and a step motor 44 for reciprocating the valve shaft 42 together with the valve body 43 in the axial direction, and a valve body 43. Includes a spring 45 for urging the valve shaft 42 in a direction away from the step motor 44. The valve shaft 42 is arranged so as to penetrate the center of the housing 41, and a male screw 46 is provided at the upper end portion. The step motor 44 corresponds to an example of the actuator of this disclosed technique.

ハウジング４１は、ＥＧＲ弁１４の外側を覆う外ハウジング６１と、外ハウジング６１の内側に配置される内ハウジング６２と、内ハウジング６２の下部内側に配置される軸受ハウジング６３とを含む。内ハウジング６２の上部は、ステップモータ４４のステータ７１を構成し、その外周にはコイル７２が設けられる。軸受ハウジング６３は、その中心部に弁軸４２をスラスト方向へ往復動可能に支持するスラスト軸受部６３ａを含み、スラスト軸受部６３ａの周囲は中空となっている。ステータ７１の内側には、ステップモータ４４を構成するロータ７３が配置される。外ハウジング６１には、上方へ突出するコネクタ６１ａが形成される。コネクタ６１ａには、コイル７２に接続される端子７４が設けられる。外ハウジング６１の下部には、フランジ６１ｂが形成される。ＥＧＲクーラ１３の組付部２１ｄには、フランジ２１ｄａが形成される。ＥＧＲ弁１４は、これらフランジ６１ｂ，２１ｄａを介してボルト等（図示略）によりＥＧＲクーラ１３に固定される。 The housing 41 includes an outer housing 61 that covers the outside of the EGR valve 14, an inner housing 62 that is arranged inside the outer housing 61, and a bearing housing 63 that is arranged inside the lower part of the inner housing 62. The upper part of the inner housing 62 constitutes the stator 71 of the step motor 44, and the coil 72 is provided on the outer periphery thereof. The bearing housing 63 includes a thrust bearing portion 63a that reciprocates and supports the valve shaft 42 in the thrust direction at the center thereof, and the periphery of the thrust bearing portion 63a is hollow. Inside the stator 71, a rotor 73 constituting the step motor 44 is arranged. The outer housing 61 is formed with a connector 61a projecting upward. The connector 61a is provided with a terminal 74 connected to the coil 72. A flange 61b is formed on the lower portion of the outer housing 61. A flange 21da is formed on the assembly portion 21d of the EGR cooler 13. The EGR valve 14 is fixed to the EGR cooler 13 by bolts or the like (not shown) via the flanges 61b and 21da.

ロータ７３は、ロータ本体７３ａと、ロータ本体７３ａの外周に設けられるマグネット７３ｂとを含む。ロータ本体７３ａの下端には、下方へ伸びるスリーブ７５が設けられ、スリーブ７５の外周と内ハウジング６２との間には、ラジアル軸受７６が設けられる。ロータ７３は、ラジアル軸受７６によりステータ７１の内側にて回転可能に支持される。ロータ本体７３ａの中心には、弁軸４２の雄ねじ４６に螺合される雌ねじ４７が設けられる。雄ねじ４６と雌ねじ４７との間には、弁軸４２の軸線方向において所定のバックラッシが設けられる。 The rotor 73 includes a rotor main body 73a and a magnet 73b provided on the outer periphery of the rotor main body 73a. A sleeve 75 extending downward is provided at the lower end of the rotor main body 73a, and a radial bearing 76 is provided between the outer periphery of the sleeve 75 and the inner housing 62. The rotor 73 is rotatably supported inside the stator 71 by a radial bearing 76. At the center of the rotor body 73a, a female screw 47 screwed into the male screw 46 of the valve shaft 42 is provided. A predetermined backlash is provided between the male screw 46 and the female screw 47 in the axial direction of the valve shaft 42.

図３、図５は、ＥＧＲ弁１４の内ハウジング６２の下部がＥＧＲクーラ１３の組付部２１ｄの組付孔２８に組み付けられた状態を示す。この組み付け状態において、ＥＧＲクーラ１３の出口２４と組付部２１ｄの流路２９とは、ＥＧＲクーラ１３からＥＧＲガスが流れる一連の流路４８（二点鎖線で概形を示す。）を構成する。この一連の流路４８は、出口２４に設けられた弁座３０を境として、弁座３０より下側のステップモータ４４から遠い上流側流路４８ａと、弁座３０より上側のステップモータ４４に近い下流側流路４８ｂに分かれる。弁体４３は、下流側流路４８ｂにて弁座３０に着座可能に配置される。 3 and 5 show a state in which the lower portion of the inner housing 62 of the EGR valve 14 is assembled in the assembly hole 28 of the assembly portion 21d of the EGR cooler 13. In this assembled state, the outlet 24 of the EGR cooler 13 and the flow path 29 of the assembly portion 21d form a series of flow paths 48 (the outline is shown by a two-dot chain line) through which EGR gas flows from the EGR cooler 13. .. This series of flow paths 48 is connected to the upstream flow path 48a far from the step motor 44 below the valve seat 30 and the step motor 44 above the valve seat 30 with the valve seat 30 provided at the outlet 24 as a boundary. It is divided into the near downstream flow path 48b. The valve body 43 is arranged so as to be seatable on the valve seat 30 in the downstream flow path 48b.

図３～図６に示すように、弁体４３は、その軸線方向において下側の先部４３ａと上側の基部４３ｂを含む。弁体４３は、その先部４３ａが弁座３０を貫通すると共に着座するようになっている。そして、弁軸４２は、弁体４３の基部４３ｂからステップモータ４４へ向けて伸びている。弁体４３は、先端である下方へ収束する略円錐台形状をなしている。この実施形態において、弁体４３の基部４３ｂには、弁体４３を弁軸４２と共に弁座３０から離間する方向（ステップモータ４４に近づける方向）へ付勢するように弁体４３の基部４３ｂの側に作用する圧力を低減させるための作用圧低減手段５０が設けられる。軸受ハウジング６３の内側には、作用圧低減手段５０が弁体４３及び弁軸４２と共に往復動するときに作用圧低減手段５０と軸受ハウジング６３との間をシールするためのリップシール５１が設けられる。リップシール５１は、この開示技術のシール部材の一例に相当する。この実施形態で、作用圧低減手段５０は、一例として、弁軸４２の周囲に設けられ、リップシール５１に接触可能な外周部５２ｃを含み、弁体４３の基部４３ｂから弁軸４２に沿って伸びる円筒状の外軸５２により構成される。この実施形態で、図７に示すように、外軸５２の外周部５２ｃの外径Ｄ１は、弁体４３の最大外径Ｄ２と同じに設定される。また、外軸５２の外周部５２ｃの外径Ｄ１は、弁座３０の内径Ｄ３よりも大きく設定される。 As shown in FIGS. 3 to 6, the valve body 43 includes a lower tip portion 43a and an upper base portion 43b in the axial direction thereof. The valve body 43 has a tip portion 43a that penetrates and sits on the valve seat 30. The valve shaft 42 extends from the base 43b of the valve body 43 toward the step motor 44. The valve body 43 has a substantially truncated cone shape that converges downward at the tip. In this embodiment, the base 43b of the valve body 43 has a base 43b of the valve body 43 so as to urge the valve body 43 together with the valve shaft 42 in a direction away from the valve seat 30 (a direction closer to the step motor 44). The working pressure reducing means 50 for reducing the pressure acting on the side is provided. Inside the bearing housing 63, a lip seal 51 for sealing between the working pressure reducing means 50 and the bearing housing 63 when the working pressure reducing means 50 reciprocates together with the valve body 43 and the valve shaft 42 is provided. .. The lip seal 51 corresponds to an example of a seal member of this disclosed technique. In this embodiment, the working pressure reducing means 50 is provided around the valve shaft 42 as an example, includes an outer peripheral portion 52c that can contact the lip seal 51, and is provided along the valve shaft 42 from the base portion 43b of the valve body 43. It is composed of an extending cylindrical outer shaft 52. In this embodiment, as shown in FIG. 7, the outer diameter D1 of the outer peripheral portion 52c of the outer shaft 52 is set to be the same as the maximum outer diameter D2 of the valve body 43. Further, the outer diameter D1 of the outer peripheral portion 52c of the outer shaft 52 is set to be larger than the inner diameter D3 of the valve seat 30.

ＥＧＲ弁１４には、外軸５２と軸受ハウジング６３との間をリップシール５１によりシールすることでハウジング４１の内側に区分される内側空間５３が設けられる。外軸５２の上端部５２ａ（一端部）は、この内側空間５３に面して配置される。そして、この内側空間５３を大気に連通させるために、ハウジング４１（外ハウジング６１、内ハウジング６２及び軸受ハウジング６３）には、大気通路５４（二点鎖線で概形を示す。）が設けられる。 The EGR valve 14 is provided with an inner space 53 that is divided inside the housing 41 by sealing between the outer shaft 52 and the bearing housing 63 with a lip seal 51. The upper end portion 52a (one end portion) of the outer shaft 52 is arranged so as to face the inner space 53. Then, in order to communicate the inner space 53 with the atmosphere, the housing 41 (outer housing 61, inner housing 62, and bearing housing 63) is provided with an atmospheric passage 54 (the outline is shown by a two-dot chain line).

上記のように構成したＥＧＲ弁１４は、ステップモータ４４を駆動させてロータ７３を回転させることにより、その回転運動を雄ねじ４６と雌ねじ４７を介して弁軸４２と弁体４３のストローク運動に変換し、弁座３０に対する弁体４３の開度を調節するようになっている。すなわち、ＥＧＲ弁１４は、図３に示すように、弁体４３が弁座３０に着座した全閉状態から、ロータ７３を一方向へ回転させることにより、雄ねじ４６と雌ねじ４７の螺合関係により、スプリング４５の付勢力に抗して、弁軸４２が弁体４３と共にスラスト方向である図３の上方向へストローク運動する。これにより、弁体４３が弁座３０から流路２９の側へ離間（開弁）し、更に、図５に示す全開状態となる。 The EGR valve 14 configured as described above converts the rotational movement into the stroke movement of the valve shaft 42 and the valve body 43 via the male screw 46 and the female screw 47 by driving the step motor 44 to rotate the rotor 73. However, the opening degree of the valve body 43 with respect to the valve seat 30 is adjusted. That is, as shown in FIG. 3, the EGR valve 14 has a screw relationship between the male screw 46 and the female screw 47 by rotating the rotor 73 in one direction from the fully closed state in which the valve body 43 is seated on the valve seat 30. Against the urging force of the spring 45, the valve shaft 42 makes a stroke movement in the upward direction of FIG. 3, which is the thrust direction, together with the valve body 43. As a result, the valve body 43 is separated (opened) from the valve seat 30 toward the flow path 29, and is further fully opened as shown in FIG.

一方、ＥＧＲ弁１４は、図５に示すように、弁体４３が弁座３０から最も離間した全開状態から、ロータ７３を反対方向へ回転させることにより、雄ねじ４６と雌ねじ４７の螺合関係により、スプリング４５の付勢力との協働により、弁軸４２が弁体４３と共にスラスト方向である図５の下方向へストローク運動する。これにより、弁体４３が弁座３０に着座し、図３に示す全閉状態となる。 On the other hand, as shown in FIG. 5, the EGR valve 14 has a screw relationship between the male screw 46 and the female screw 47 by rotating the rotor 73 in the opposite direction from the fully open state where the valve body 43 is most distant from the valve seat 30. In cooperation with the urging force of the spring 45, the valve shaft 42 and the valve body 43 make a stroke movement in the downward direction of FIG. 5, which is the thrust direction. As a result, the valve body 43 is seated on the valve seat 30 and is in the fully closed state shown in FIG.

［ＥＧＲ弁及びＥＧＲユニットの作用及び効果について］
以上説明したこの実施形態のＥＧＲ弁１４の構成によれば、ＥＧＲ弁１４（流体制御弁）は、流路２９と、出口２４に設けられた弁座３０とを有する相手部材としてのＥＧＲクーラ１３の組付部２１ｄに組み付けて使用される。この組み付け状態において、ＥＧＲ弁１４の弁体４３が弁座３０に着座した全閉状態では、一連の流路４８は、弁座３０を境としてステップモータ４４（アクチュエータ）から遠い、ＥＧＲクーラ１３の出口２４（上流側流路４８ａ）とステップモータ４４に近い流路２９（下流側流路４８ｂ）に分けられる。この場合、流路２９（下流側流路４８ｂ）にて弁体４３が弁座３０に着座可能に配置される。 [About the action and effect of EGR valve and EGR unit]
According to the configuration of the EGR valve 14 of this embodiment described above, the EGR valve 14 (fluid control valve) is an EGR cooler 13 as a mating member having a flow path 29 and a valve seat 30 provided at the outlet 24. It is used by assembling it to the assembly portion 21d of. In this assembled state, in the fully closed state in which the valve body 43 of the EGR valve 14 is seated on the valve seat 30, the series of flow paths 48 is far from the step motor 44 (actuator) with the valve seat 30 as a boundary, and the EGR cooler 13 It is divided into an outlet 24 (upstream side flow path 48a) and a flow path 29 (downstream side flow path 48b) close to the step motor 44. In this case, the valve body 43 is arranged so as to be seatable on the valve seat 30 in the flow path 29 (downstream side flow path 48b).

ここで、ＥＧＲ弁１４の全閉状態において、弁体４３の先部４３ａの側には、ＥＧＲクーラ１３の出口２４（上流側流路４８ａ）におけるＥＧＲガスの圧力が作用し、弁体４３の基部４３ｂの側には、流路２９（下流側流路４８ｂ）におけるＥＧＲガス又は吸気の圧力が作用する。そして、エンジン１の減速運転時等には、流路２９（下流側流路４８ｂ）に吸気通路２から高い吸気負圧が作用し、ＥＧＲクーラ１３の出口２４（上流側流路４８ａ）にほぼ大気圧（非常に低い正圧）が作用することがある。この場合、弁体４３には、出口２４（上流側流路４８ａ）の大気圧と流路２９（下流側流路４８ｂ）の高い吸気負圧との圧力差が、弁体４３を弁座３０から離間させる方向に作用し、弁体４３が不用意に弁座３０から離間（開弁）するおそれがある。この不用意な開弁を回避するために、従来は、スプリング４５の付勢力を増大させたり、全閉状態を保つためにステップモータ４４を動作させたりすることが考えられた。 Here, in the fully closed state of the EGR valve 14, the pressure of the EGR gas at the outlet 24 (upstream side flow path 48a) of the EGR cooler 13 acts on the side of the tip portion 43a of the valve body 43, and the valve body 43. The EGR gas or intake pressure in the flow path 29 (downstream side flow path 48b) acts on the side of the base portion 43b. Then, during deceleration operation of the engine 1, a high intake negative pressure acts on the flow path 29 (downstream side flow path 48b) from the intake passage 2, and substantially the outlet 24 (upstream side flow path 48a) of the EGR cooler 13. Atmospheric pressure (very low positive pressure) may act. In this case, the pressure difference between the atmospheric pressure at the outlet 24 (upstream side flow path 48a) and the high intake negative pressure at the flow path 29 (downstream side flow path 48b) causes the valve body 43 to have the valve seat 30. The valve body 43 may inadvertently separate (open) from the valve seat 30 due to the action in the direction of separating from the valve seat 30. In order to avoid this careless valve opening, conventionally, it has been considered to increase the urging force of the spring 45 or to operate the step motor 44 in order to keep the fully closed state.

この点、この実施形態のＥＧＲ弁１４の構成によれば、弁体４３の基部４３ｂには、弁体４３を弁軸４２と共にステップモータ４４に近づける方向へ付勢するように弁体４３の基部４３ｂの側に作用する圧力を低減させるための作用圧低減手段５０が設けられる。また、この作用圧低減手段５０の上端部５２ａ（一端部）が、リップシール５１（シール部材）により流路２９（下流側流路４８ｂ）と区分されるハウジング４１の内側空間５３に面して配置される。この内側空間５３は、大気通路５４を介して常に大気圧に保たれる。従って、弁体４３には、弁座３０に着座する方向（弁体４３をステップモータ４４から遠ざける方向）へ作用圧低減手段５０を介して大気圧が作用するので、流路２９（下流側流路４８ｂ）にて弁体４３を弁座３０から離間させる方向（弁体４３をステップモータ４４に近づける方向）へ高い吸気負圧が作用しても、作用圧低減手段５０に作用する大気圧の分だけ弁体４３の基部４３ｂの側に作用する高い吸気負圧による付勢力が低減される。この実施形態では、作用圧低減手段５０が外軸５２により構成され、その外軸５２の外周部５２ｃの外径Ｄ１が弁座３０の内径Ｄ３よりも大きく設定されるので、エンジン１の減速運転時に、ＥＧＲクーラ１３の出口２４から弁体４３の先部４３ａの側に作用する大気圧による付勢力よりも、スプリング４５の付勢力に加えて、内側空間５３から外軸５２を介して弁体４３の基部４３ｂの側に作用する大気圧による付勢力の方が大きくなり、弁体４３が弁座３０に着座する方向へ付勢される。このため、ポペット式であって内開式として機能するＥＧＲ弁１４において、その全閉時に流路２９（下流側流路４８ｂ）に作用する高い吸気負圧により弁体４３が不用意に開弁してしまうことを防止することができる。この場合、弁体４３を全閉状態に保つためにステップモータ４４の要求駆動トルクを増大させる必要がなく、ステップモータ４４の小型化を図ることができる。 In this respect, according to the configuration of the EGR valve 14 of this embodiment, the base portion 43b of the valve body 43 is urged so as to urge the valve body 43 together with the valve shaft 42 toward the step motor 44. The working pressure reducing means 50 for reducing the pressure acting on the side of 43b is provided. Further, the upper end portion 52a (one end portion) of the working pressure reducing means 50 faces the inner space 53 of the housing 41 which is separated from the flow path 29 (downstream side flow path 48b) by the lip seal 51 (seal member). Be placed. The inner space 53 is always maintained at atmospheric pressure via the atmospheric passage 54. Therefore, since the atmospheric pressure acts on the valve body 43 in the direction of seating on the valve seat 30 (the direction in which the valve body 43 is moved away from the step motor 44) via the acting pressure reducing means 50, the flow path 29 (downstream side flow). Even if a high intake negative pressure acts in the direction of separating the valve body 43 from the valve seat 30 (the direction in which the valve body 43 approaches the step motor 44) in the path 48b), the atmospheric pressure acting on the acting pressure reducing means 50 The urging force due to the high intake negative pressure acting on the side of the base portion 43b of the valve body 43 is reduced by the amount. In this embodiment, the working pressure reducing means 50 is composed of the outer shaft 52, and the outer diameter D1 of the outer peripheral portion 52c of the outer shaft 52 is set to be larger than the inner diameter D3 of the valve seat 30, so that the deceleration operation of the engine 1 is performed. Occasionally, in addition to the urging force of the spring 45, the valve body from the inner space 53 via the outer shaft 52, rather than the urging force due to the atmospheric pressure acting from the outlet 24 of the EGR cooler 13 to the side of the tip portion 43a of the valve body 43. The urging force due to the atmospheric pressure acting on the side of the base portion 43b of the 43 becomes larger, and the valve body 43 is urged in the direction of being seated on the valve seat 30. Therefore, in the EGR valve 14 which is a poppet type and functions as an inwardly open type, the valve body 43 carelessly opens due to the high intake negative pressure acting on the flow path 29 (downstream side flow path 48b) when the valve 14 is fully closed. It is possible to prevent this from happening. In this case, it is not necessary to increase the required drive torque of the step motor 44 in order to keep the valve body 43 in the fully closed state, and the step motor 44 can be downsized.

この実施形態の構成によれば、作用圧低減手段５０が、弁軸４２の周囲にてリップシール５１に接触可能な外周部５２ｃを含み、弁体４３の基部４３ｂから弁軸４２に沿って伸びる円筒状の外軸５２により構成される。従って、弁体４３には、弁体４３が弁座３０に着座する方向へ、外軸５２を介して内側空間５３から大気圧が作用するので、流路２９（下流側流路４８ｂ）にて弁体４３を弁座３０から離間させる方向へ高い吸気負圧が作用しても、外軸５２に作用する大気圧の分だけ弁体４３の基部４３ｂの側に作用する高い吸気負圧による付勢力が低減される。特に、この実施形態では、外軸５２の外周部５２ｃの外径Ｄ１が、弁体４３の最大外径Ｄ２と同じに設定されるので、弁体４３の基部４３ｂが流路２９（下流側流路４８ｂ）に露出せず、その基部４３ｂに、弁体４３を弁座３０から離間させる方向に、高い吸気負圧が作用することがない。このため、ＥＧＲ弁１４の全閉時に、流路２９（下流側流路４８ｂ）に作用する高い吸気負圧により弁体４３が不用意に開弁することを確実に防止することができる。また、弁軸４２と外軸５２との間のスペースにスプリング４５の配置が可能になるので、スプリング４５が流路２９（下流側流路４８ｂ）に露出することがない。このため、弁体４３の周囲を簡素化することができ、ハウジング４１の小型化が可能となると共に、流路２９（下流側流路４８ｂ）におけるＥＧＲガスの圧損を低減することができる。 According to the configuration of this embodiment, the working pressure reducing means 50 includes an outer peripheral portion 52c that can contact the lip seal 51 around the valve shaft 42, and extends from the base portion 43b of the valve body 43 along the valve shaft 42. It is composed of a cylindrical outer shaft 52. Therefore, since the atmospheric pressure acts on the valve body 43 from the inner space 53 via the outer shaft 52 in the direction in which the valve body 43 is seated on the valve seat 30, at the flow path 29 (downstream side flow path 48b). Even if a high intake negative pressure acts in the direction that separates the valve body 43 from the valve seat 30, the high intake negative pressure that acts on the base 43b side of the valve body 43 by the amount of the atmospheric pressure acting on the outer shaft 52 is applied. The power is reduced. In particular, in this embodiment, the outer diameter D1 of the outer peripheral portion 52c of the outer shaft 52 is set to be the same as the maximum outer diameter D2 of the valve body 43, so that the base portion 43b of the valve body 43 is the flow path 29 (downstream side flow). It is not exposed to the road 48b), and a high intake negative pressure does not act on the base 43b in the direction of separating the valve body 43 from the valve seat 30. Therefore, when the EGR valve 14 is fully closed, it is possible to reliably prevent the valve body 43 from being inadvertently opened due to the high intake negative pressure acting on the flow path 29 (downstream side flow path 48b). Further, since the spring 45 can be arranged in the space between the valve shaft 42 and the outer shaft 52, the spring 45 is not exposed to the flow path 29 (downstream side flow path 48b). Therefore, the circumference of the valve body 43 can be simplified, the housing 41 can be miniaturized, and the pressure loss of the EGR gas in the flow path 29 (downstream side flow path 48b) can be reduced.

この実施形態の構成によれば、ＥＧＲクーラ１３の出口２４に対応してＥＧＲクーラ１３に一体に設けられたＥＧＲ弁１４により内開式のポペット弁が構成される。従って、ＥＧＲ弁１４の開弁時には、弁体４３及び弁軸４２が、流路２９（下流側流路４８ｂ）にて弁座３０からステップモータ４４に近づく方向へ離間し、出口２４（上流側流路４８ａ）にてステップモータ４４から遠ざかる方向へ離間することがない。このため、ＥＧＲクーラ１３の出口２４（上流側流路４８ａ）におけるＥＧＲガスの圧損を低減することができ、ＥＧＲガスをＥＧＲクーラ１３からＥＧＲ弁１４へ流れ易くすることができる。 According to the configuration of this embodiment, the inwardly open poppet valve is configured by the EGR valve 14 integrally provided in the EGR cooler 13 corresponding to the outlet 24 of the EGR cooler 13. Therefore, when the EGR valve 14 is opened, the valve body 43 and the valve shaft 42 are separated from the valve seat 30 in the flow path 29 (downstream side flow path 48b) in the direction approaching the step motor 44, and the outlet 24 (upstream side). The flow path 48a) does not separate from the step motor 44 in the direction away from it. Therefore, the pressure loss of the EGR gas at the outlet 24 (upstream side flow path 48a) of the EGR cooler 13 can be reduced, and the EGR gas can be easily flowed from the EGR cooler 13 to the EGR valve 14.

＜第２実施形態＞
次に、第２実施形態について図面を参照して詳細に説明する。 <Second Embodiment>
Next, the second embodiment will be described in detail with reference to the drawings.

［ＥＧＲ弁の構成について］
この実施形態のＥＧＲ弁１４は、外軸５２の構成の点で第１実施形態と異なる。図８に、全閉に動作したＥＧＲ弁１４を図７に準ずる簡略化した断面図により示す。この実施形態のＥＧＲ弁１４の外軸５２は、外周部５２ｃに、弁体４３の最大外径Ｄ２より大きく、リップシール５１に接触可能な外径Ｄ４を有する拡径部５２ｂが設けられる。この拡径部５２ｂの上端部５２ｂａ（一端部）は、内側空間５３に面して配置され、反対側の下端部５２ｂｂ（他端部）は、弁体４３へ向いて配置されることで流路２９（下流側流路４８ｂ）に面して配置される。 [About the configuration of the EGR valve]
The EGR valve 14 of this embodiment is different from the first embodiment in that the outer shaft 52 is configured. FIG. 8 shows a simplified cross-sectional view of the EGR valve 14 operated in a fully closed manner according to FIG. 7. The outer shaft 52 of the EGR valve 14 of this embodiment is provided with an enlarged diameter portion 52b having an outer diameter D4 that is larger than the maximum outer diameter D2 of the valve body 43 and can be contacted with the lip seal 51 on the outer peripheral portion 52c. The upper end portion 52ba (one end portion) of the enlarged diameter portion 52b is arranged so as to face the inner space 53, and the lower end portion 52bb (the other end portion) on the opposite side is arranged so as to face the valve body 43. It is arranged facing the road 29 (downstream side flow path 48b).

この実施形態のＥＧＲ弁１４の構成によれば、第１実施形態の作用及び効果に加え、次のような作用及び効果を有する。すなわち、拡径部５２ｂの下端部５２ｂｂ（他端部）が弁体４３へ向いて配置されることで流路２９（下流側流路４８ｂ）に面するので、流路２９（下流側流路４８ｂ）に作用する高い吸気負圧が、拡径部５２ｂの下端部５２ｂｂに作用し、外軸５２を介して弁体４３が弁座３０に着座する方向に付勢される。従って、その付勢力の分だけ弁体４３を弁座３０から離間させる方向へ作用する高い吸気負圧による付勢力が更に低減される。この場合、弁体４３の前後差圧により弁体４３が弁座３０に押し付けられることになる。このため、ＥＧＲ弁１４の全閉時に、流路２９（下流側流路４８ｂ）に作用する高い吸気負圧により弁体４３が不用意に開弁することをより確実に防止することができる。 According to the configuration of the EGR valve 14 of this embodiment, it has the following actions and effects in addition to the actions and effects of the first embodiment. That is, since the lower end portion 52bb (the other end portion) of the enlarged diameter portion 52b faces the flow path 29 (downstream side flow path 48b) by being arranged toward the valve body 43, the flow path 29 (downstream side flow path) The high intake negative pressure acting on 48b) acts on the lower end portion 52bb of the enlarged diameter portion 52b, and the valve body 43 is urged in the direction of being seated on the valve seat 30 via the outer shaft 52. Therefore, the urging force due to the high intake negative pressure acting in the direction of separating the valve body 43 from the valve seat 30 by the amount of the urging force is further reduced. In this case, the valve body 43 is pressed against the valve seat 30 by the front-rear differential pressure of the valve body 43. Therefore, when the EGR valve 14 is fully closed, it is possible to more reliably prevent the valve body 43 from being inadvertently opened due to the high intake negative pressure acting on the flow path 29 (downstream side flow path 48b).

＜第３実施形態＞
次に、第３実施形態について図面を参照して詳細に説明する。 <Third Embodiment>
Next, the third embodiment will be described in detail with reference to the drawings.

［ＥＧＲ弁の構成について］
この実施形態のＥＧＲ弁１４は、作用圧低減手段５０の構成の点で前記各実施形態と異なる。図９に、全閉に動作したＥＧＲ弁１４を図７に準ずる簡略化した断面図により示す。この実施形態の作用圧低減手段５０は、弁軸４２上にて弁体４３から離れて設けられ、リップシール５１に接触可能な外周部５６ｃと、弁体４３の基部４３ｂに対向することで流路２９（下流側流路４８ｂ）に面する下面５６ａａ（他端部）とを含み、内側空間５３を閉鎖する閉鎖部材５６により構成される。この実施形態の閉鎖部材５６は、有底な短円筒形状をなし、弁軸４２が貫通する底壁５６ａと、リップシール５１に接触可能な外周部５６ｃを含む周壁５６ｂとを含む。この実施形態で、周壁５６ｂは、弁体４３の最大外径Ｄ２より大きい外径Ｄ５を有する。周壁５６ｂの上端部５６ｂａ（一端部）は、内側空間５３に面して配置され、底壁５６ａの下面５６ａａ（他端部）は、流路２９（下流側流路４８ｂ）に面して配置される。 [About the configuration of the EGR valve]
The EGR valve 14 of this embodiment is different from each of the above-described embodiments in the configuration of the working pressure reducing means 50. FIG. 9 shows a simplified cross-sectional view of the EGR valve 14 operated in a fully closed manner according to FIG. 7. The working pressure reducing means 50 of this embodiment is provided on the valve shaft 42 away from the valve body 43, and flows by facing the outer peripheral portion 56c that can contact the lip seal 51 and the base portion 43b of the valve body 43. It includes a lower surface 56aa (the other end) facing the road 29 (downstream side flow path 48b), and is composed of a closing member 56 that closes the inner space 53. The closing member 56 of this embodiment has a bottomed short cylindrical shape and includes a bottom wall 56a through which the valve shaft 42 penetrates and a peripheral wall 56b including an outer peripheral portion 56c that can contact the lip seal 51. In this embodiment, the peripheral wall 56b has an outer diameter D5 larger than the maximum outer diameter D2 of the valve body 43. The upper end portion 56ba (one end portion) of the peripheral wall 56b is arranged so as to face the inner space 53, and the lower surface 56aa (the other end portion) of the bottom wall 56a is arranged so as to face the flow path 29 (downstream side flow path 48b). Will be done.

この実施形態のＥＧＲ弁１４の構成によれば、前記各実施形態の作用及び効果と異なり次のような作用及び効果を有する。すなわち、閉鎖部材５６の上端部５６ｂａ（一端部）が内側空間５３に面するので、弁体４３には、弁体４３が弁座３０に着座する方向へ閉鎖部材５６を介して内側空間５３から大気圧が作用する。従って、流路２９（下流側流路４８ｂ）にて弁体４３を弁座３０から離間させる方向へ高い吸気負圧が作用しても、閉鎖部材５６に作用する大気圧の分だけ弁体４３の基部４３ｂの側に作用する高い吸気負圧による付勢力が低減される。また、閉鎖部材５６の下面５６ａａ（他端部）が弁体４３の基部４３ｂに対向することで流路２９（下流側流路４８ｂ）に面するので、流路２９（下流側流路４８ｂ）に作用する高い吸気負圧が、閉鎖部材５６を介して、弁体４３が弁座３０に着座する方向に作用する。従って、閉鎖部材５６に作用する高い吸気負圧の分だけ弁体４３を弁座３０から離間させる方向へ作用する高い吸気負圧による付勢力が低減される。この場合、弁体４３の前後差圧により弁体４３が弁座３０に押し付けられる。このため、ＥＧＲ弁１４の全閉時に、流路２９（下流側流路４８ｂ）に作用する高い吸気負圧により弁体４３が不用意に開弁することをより確実に防止することができる。 According to the configuration of the EGR valve 14 of this embodiment, it has the following actions and effects unlike the actions and effects of each of the above-described embodiments. That is, since the upper end portion 56ba (one end portion) of the closing member 56 faces the inner space 53, the valve body 43 is provided with the valve body 43 from the inner space 53 via the closing member 56 in the direction in which the valve body 43 is seated on the valve seat 30. Atmospheric pressure acts. Therefore, even if a high intake negative pressure acts in the flow path 29 (downstream side flow path 48b) in the direction of separating the valve body 43 from the valve seat 30, the valve body 43 acts on the closing member 56 by the amount of atmospheric pressure. The urging force due to the high intake negative pressure acting on the side of the base 43b is reduced. Further, since the lower surface 56aa (the other end) of the closing member 56 faces the flow path 29 (downstream side flow path 48b) by facing the base portion 43b of the valve body 43, the flow path 29 (downstream side flow path 48b). The high intake negative pressure acting on the valve body 43 acts in the direction in which the valve body 43 is seated on the valve seat 30 via the closing member 56. Therefore, the urging force due to the high intake negative pressure acting in the direction of separating the valve body 43 from the valve seat 30 is reduced by the amount of the high intake negative pressure acting on the closing member 56. In this case, the valve body 43 is pressed against the valve seat 30 by the front-rear differential pressure of the valve body 43. Therefore, when the EGR valve 14 is fully closed, it is possible to more reliably prevent the valve body 43 from being inadvertently opened due to the high intake negative pressure acting on the flow path 29 (downstream side flow path 48b).

＜第４実施形態＞
次に、第４実施形態について図面を参照して詳細に説明する。 <Fourth Embodiment>
Next, the fourth embodiment will be described in detail with reference to the drawings.

［ＥＧＲ弁の構成について］
この実施形態は、ＥＧＲ弁の構成の点で前記各実施形態と異なる。図１０に、全閉に動作したＥＧＲ弁１９を断面図により示す。この実施形態のＥＧＲ弁１９は、ハウジング４１が、外ハウジング６１、内ハウジング６２及び軸受ハウジング６３の他に、ＥＧＲガスが流れる流路６６を有する流路ハウジング６７を更に備える。流路ハウジング６７は、流路６６の入口６８と出口６９を有する。流路６６には、弁体４３の先部４３ａが着座又は離間する弁座３０が設けられる。流路６６は、弁座３０を境としてステップモータ４４から遠い下側の上流側流路６６ａとステップモータ４４に近い上側の下流側流路６６ｂに分かれる。弁体４３は、下流側流路６６ｂにて弁座３０に着座可能に配置される。流路ハウジング６７の入口６８の外周には、ＥＧＲ通路の上流側（図示略）に接続される入口フランジ６７ａが形成され、出口６９の外周には、ＥＧＲ通路の下流側（図示略）に接続される出口フランジ６７ｂが形成される。その他の構成は、第１実施形態で説明したＥＧＲ弁１４のそれと同じである。 [About the configuration of the EGR valve]
This embodiment differs from each of the above embodiments in the configuration of the EGR valve. FIG. 10 shows a cross-sectional view of the EGR valve 19 operated in a fully closed state. In the EGR valve 19 of this embodiment, the housing 41 further includes a flow path housing 67 having a flow path 66 through which EGR gas flows, in addition to the outer housing 61, the inner housing 62, and the bearing housing 63. The flow path housing 67 has an inlet 68 and an outlet 69 of the flow path 66. The flow path 66 is provided with a valve seat 30 in which the tip portion 43a of the valve body 43 is seated or separated. The flow path 66 is divided into a lower upstream flow path 66a far from the step motor 44 and an upper downstream flow path 66b close to the step motor 44 with the valve seat 30 as a boundary. The valve body 43 is arranged so as to be seatable on the valve seat 30 in the downstream flow path 66b. An inlet flange 67a connected to the upstream side (not shown) of the EGR passage is formed on the outer periphery of the inlet 68 of the flow path housing 67, and is connected to the downstream side (not shown) of the EGR passage on the outer periphery of the outlet 69. The outlet flange 67b to be formed is formed. Other configurations are the same as those of the EGR valve 14 described in the first embodiment.

この実施形態のＥＧＲ弁１９の構成によれば、第１実施形態の作用及び効果に加え、次のような作用及び効果を有する。すなわち、ハウジング４１を構成する流路ハウジング６７に流路６６と弁座３０が一体に設けられるので、ＥＧＲ弁１９を流路と弁座を有する別の相手部材に組み付ける必要がない。このため、ＥＧＲ弁１９それのみをＥＧＲガスが流れるＥＧＲ通路の任意の位置に接続するだけで、ＥＧＲガスの流量制御に使用できるようになる。 According to the configuration of the EGR valve 19 of this embodiment, it has the following actions and effects in addition to the actions and effects of the first embodiment. That is, since the flow path 66 and the valve seat 30 are integrally provided in the flow path housing 67 constituting the housing 41, it is not necessary to assemble the EGR valve 19 to another mating member having the flow path and the valve seat. Therefore, the EGR valve 19 alone can be used for controlling the flow rate of the EGR gas only by connecting it to an arbitrary position in the EGR passage through which the EGR gas flows.

なお、この開示技術は前記実施形態に限定されるものではなく、開示技術の趣旨を逸脱することのない範囲で構成の一部を適宜変更して実施することもできる。 The disclosed technique is not limited to the above-described embodiment, and a part of the configuration may be appropriately modified and implemented without departing from the spirit of the disclosed technique.

（１）前記第２実施形態では、外軸５２の外周部５２ｃに拡径部５２ｂを設けたが、前記第３実施形態の閉鎖部材５６の外周部４６ｃにも拡径部を設けることができる。 (1) In the second embodiment, the enlarged diameter portion 52b is provided on the outer peripheral portion 52c of the outer shaft 52, but the enlarged diameter portion can also be provided on the outer peripheral portion 46c of the closing member 56 of the third embodiment. ..

（２）前記各実施形態では、ＥＧＲクーラ１３へ流れるＥＧＲガスをバイパスするバイパス通路と、バイパス通路を開閉するバイパス弁を設けていないが、これらバイパス通路とバイパス弁を設けてもよい。 (2) In each of the above embodiments, the bypass passage for bypassing the EGR gas flowing to the EGR cooler 13 and the bypass valve for opening and closing the bypass passage are not provided, but these bypass passages and the bypass valve may be provided.

（３）前記第４実施形態において、内ハウジング６２と流路ハウジング６７を一体に成形することもできる。 (3) In the fourth embodiment, the inner housing 62 and the flow path housing 67 can be integrally molded.

（４）前記各実施形態では、流体制御弁をＥＧＲガスの流量を制御するＥＧＲ弁１４，１９に具体化したが、ＥＧＲガス以外の流体（例えば、吸気）を制御する弁装置（例えば、アイドル・スピード・コントロール・バルブ（ＩＳＣＶ））に具体化することもできる。 (4) In each of the above embodiments, the fluid control valve is embodied as EGR valves 14 and 19 for controlling the flow rate of EGR gas, but a valve device (for example, idle) for controlling a fluid other than EGR gas (for example, intake). -It can also be embodied in a speed control valve (ISCV).

この開示技術は、例えば、ガソリンエンジンやディーゼルエンジンに装備するＥＧＲ装置に適用できる。 This disclosed technique can be applied to, for example, an EGR device installed in a gasoline engine or a diesel engine.

１３ＥＧＲクーラ
１４ＥＧＲ弁（流体制御弁）
１９ＥＧＲ弁（流体制御弁）
２３入口
２４出口
２９流路
３０弁座
４１ハウジング
４２弁軸
４３弁体
４３ａ先部
４３ｂ基部
４４ステップモータ（アクチュエータ）
４５スプリング
４８一連の流路
４８ａ上流側流路
４８ｂ下流側流路
５０作用圧低減手段
５１リップシール（シール部材）
５２外軸（作用圧低減手段）
５２ａ上端部（一端部）
５２ｂ拡径部
５２ｂａ上端部（一端部）
５２ｂｂ下端部（他端部）
５２ｃ外周部
５３内側空間
５４大気通路
５６閉鎖部材（作用圧低減手段）
５６ａａ下面（他端部）
５６ｃ外周部
５６ｂａ上端部（一端部）
６６流路
６６ａ上流側流路
６６ｂ下流側流路 13 EGR cooler 14 EGR valve (fluid control valve)
19 EGR valve (fluid control valve)
23 Inlet 24 Outlet 29 Flow path 30 Valve seat 41 Housing 42 Valve shaft 43 Valve body 43a Tip 43b Base 44 Step motor (actuator)
45 Spring 48 Series of flow paths 48a Upstream side flow path 48b Downstream side flow path 50 Working pressure reducing means 51 Lip seal (seal member)
52 Outer shaft (means for reducing working pressure)
52a Upper end (one end)
52b Enlarged diameter 52ba Upper end (one end)
52bb Lower end (the other end)
52c Outer peripheral 53 Inner space 54 Atmospheric passage 56 Closing member (acting pressure reducing means)
56aa Bottom surface (other end)
56c Outer peripheral part 56ba Upper end part (one end part)
66 Flow path 66a Upstream side flow path 66b Downstream side flow path

Claims

With the housing
A valve shaft provided in the housing and including one end and the other end,
A valve body provided at the one end of the valve shaft and
An actuator provided in the housing corresponding to the other end of the valve shaft and for reciprocating the valve shaft together with the valve body in the axial direction.
The valve body includes a tip portion and a base portion in the axial direction.
The valve shaft extends from the base of the valve body toward the actuator, and
In a fluid control valve that controls the flow rate of a fluid, the valve body is provided with a spring for urging the valve body together with the valve shaft in a direction away from the actuator.
To reduce the pressure applied to the base of the valve body or the valve shaft so as to urge the valve body together with the valve shaft in a direction toward the actuator. Actuating pressure reducing means and
A sealing member for sealing between the working pressure reducing means and the housing when the working pressure reducing means reciprocates together with the valve body and the valve shaft.
An inner space defined inside the housing by sealing between the working pressure reducing means and the housing with the sealing member.
The working pressure reducing means includes one end portion, and the one end portion is arranged so as to face the inner space.
A fluid control valve including an air passage provided in the housing for communicating the inner space with the atmosphere.

In the fluid control valve according to claim 1,
The working pressure reducing means is a cylindrical outer shaft provided around the valve shaft, including an outer peripheral portion that can come into contact with the seal member, and extends from the base portion of the valve body along the valve shaft. A fluid control valve characterized by.

In the fluid control valve according to claim 1,
The working pressure reducing means includes an outer peripheral portion provided on the valve shaft away from the valve body and capable of contacting the seal member, and the other end portion of the valve body facing the base portion. A fluid control valve characterized by being a closing member that closes the inner space.

In the fluid control valve according to claim 2 or 3.
The outer shaft or the closing member includes a diameter-expanding portion that expands the outer diameter in the outer peripheral portion, one end portion of the diameter-expanding portion is arranged facing the inner space, and the other end portion is the valve body. A fluid control valve characterized by being placed facing towards.

In the fluid control valve according to any one of claims 1 to 4.
A flow path provided in the housing through which the fluid flows,
Further provided with a valve seat provided in the flow path and where the tip of the valve body is seated or separated.
The flow path is divided into an upstream side flow path far from the actuator and a downstream side flow path close to the actuator with the valve seat as a boundary, and the valve body is arranged so as to be able to sit on the valve seat in the downstream side flow path. A fluid control valve characterized by being

In the fluid control valve according to any one of claims 1 to 5.
The fluid is an EGR gas, and the fluid control valve is an EGR valve that controls the flow rate of the EGR gas.

The EGR valve according to claim 6 and
It is equipped with an EGR cooler for cooling the EGR gas.
The EGR cooler includes an inlet into which the EGR gas flows in and an outlet in which the EGR gas flows out.
The EGR valve is an EGR unit provided integrally with the EGR cooler corresponding to the outlet of the EGR cooler.