JP6839164B2

JP6839164B2 - Electric valve

Info

Publication number: JP6839164B2
Application number: JP2018241959A
Authority: JP
Inventors: 吉田　竜也; 竜也吉田; 将志矢沢
Original assignee: Fujikoki Corp
Current assignee: Fujikoki Corp
Priority date: 2018-12-26
Filing date: 2018-12-26
Publication date: 2021-03-03
Anticipated expiration: 2036-08-30
Also published as: JP2019060498A

Description

本発明は、弁室及び弁口（オリフィス）が設けられた弁本体と、リフト量に応じて前記弁口を流れる流体の流量を変化させる弁体とを備えた電動弁に係り、特に、ヒートポンプ式冷暖房システム等において冷媒流量を制御するのに好適な電動弁に関する。 The present invention relates to an electric valve including a valve body provided with a valve chamber and a valve port (orifice) and a valve body that changes the flow rate of a fluid flowing through the valve port according to a lift amount, and particularly a heat pump. The present invention relates to an electric valve suitable for controlling a refrigerant flow rate in a type heating / cooling system or the like.

この種の電動弁として、例えば特許文献１に所載のものが既に知られている。 As an electric valve of this type, for example, the one described in Patent Document 1 is already known.

図７は、前記した従来例の電動弁の要部を示している。図示従来例の電動弁２は、弁室４０ａ、弁座４６ａ、及び該弁座４６ａに連なる弁口４６が設けられた弁本体４０と、弁座４６ａからのリフト量に応じて弁口４６を流れる流体の流量を変化させる弁体１４とを備え、弁体１４は、例えば特許文献１等に所載の如くの、雄ねじ部が設けられたねじ管（ガイドブッシュともいう）、雌ねじ部が設けられた弁軸ホルダ、及びステッピングモータ等で構成されるねじ送り式昇降駆動機構により、弁座４６ａに接離するように昇降せしめられる。 FIG. 7 shows a main part of the electric valve of the conventional example described above. The electric valve 2 of the conventional example shown has a valve body 40 provided with a valve chamber 40a, a valve seat 46a, and a valve port 46 connected to the valve seat 46a, and a valve port 46 according to the amount of lift from the valve seat 46a. The valve body 14 includes a valve body 14 that changes the flow rate of the flowing fluid, and the valve body 14 is provided with a threaded pipe (also referred to as a guide bush) provided with a male threaded portion and a female threaded portion as described in, for example, Patent Document 1. It is moved up and down so as to be brought into contact with and separated from the valve seat 46a by a screw feed type elevating drive mechanism composed of a valve shaft holder, a stepping motor, and the like.

弁体１４は、弁座４６ａに着接する逆円錐台面からなる着座面部１４ａと、該着座面部１４ａの下側（先端側）に連なる、リフト量に応じて弁口４６を流れる流体の流量を変化させるための曲面部１４ｂとを有する。曲面部１４ｂは、先端に近づくに従って制御角（弁体１４の中心軸線Ｏと平行な線との交差角）が段階的に大きくされた複数段（ここでは２段）の逆円錐台状のテーパ面部（上側テーパ面部１４ｂａ及び下側テーパ面部１４ｂｂ）を有する。なお、曲面部１４ｂとしては、先端に近づくに従って次第にその外周面の曲がり具合がきつく（曲率が大きく）なっている楕球状のもの（楕球面部）なども知られている。 The valve body 14 changes the flow rate of the fluid flowing through the valve port 46 according to the lift amount, which is connected to the seating surface portion 14a formed of the inverted conical base surface that contacts the valve seat 46a and the lower side (tip side) of the seating surface portion 14a. It has a curved surface portion 14b for making the surface. The curved surface portion 14b is a multi-stage (here, two-stage) inverted truncated cone-shaped taper in which the control angle (intersection angle between the central axis O of the valve body 14 and the line parallel to the valve body 14) is gradually increased as it approaches the tip. It has a surface portion (upper tapered surface portion 14ba and lower tapered surface portion 14bb). As the curved surface portion 14b, an elliptical spherical surface portion (elliptical spherical surface portion) in which the bending degree of the outer peripheral surface thereof gradually becomes tighter (larger curvature) as it approaches the tip is also known.

一方、弁口４６は、弁座４６ａに連なる円筒面からなる最狭部４６ｓと、該最狭部４６ｓの下側に連なる、下側に行くに従って内径が大きくされた円錐台面からなる拡径部４６ｃとを有する。 On the other hand, the valve port 46 is a diameter-expanded portion composed of a narrowest portion 46s formed of a cylindrical surface connected to the valve seat 46a and a conical base surface connected to the lower side of the narrowest portion 46s and whose inner diameter is increased toward the lower side. It has 46c and.

特開２０１１−２０８７１６号公報Japanese Unexamined Patent Publication No. 2011-208716

ところで、この種の電動弁においては、近年、Ｒ３２冷媒の利用や部分負荷運転の増加等により、低流量域での制御性の向上が求められている。また、マルチエアコン等の冷暖房システムに用いられる閉弁タイプの電動弁においても同様で、立上り流量の低減が望まれている。 By the way, in recent years, in this type of electric valve, improvement in controllability in a low flow rate region is required due to the use of R32 refrigerant, an increase in partial load operation, and the like. The same applies to a closed valve type electric valve used in a cooling / heating system such as a multi air conditioner, and it is desired to reduce the rising flow rate.

しかし、図７に示される如くの前記従来例の電動弁では、前記立上り流量が、着座面部１４ａと曲面部１４ｂ（上側テーパ面部１４ｂａ）との交差部分の外径（φＡ）と弁口４６の最狭部４６ｓの口径（φＢ）との差により形成されており、前記交差部分の外径（φＡ）の寸法測定（特に、接触式計測器による寸法測定）が複雑であるため、当該立上り流量の管理が難しいという課題があった。 However, in the electric valve of the conventional example as shown in FIG. 7, the rising flow rate is the outer diameter (φA) of the intersection of the seating surface portion 14a and the curved surface portion 14b (upper tapered surface portion 14ba) and the valve port 46. Since it is formed by the difference from the diameter (φB) of the narrowest portion 46s and the dimensional measurement of the outer diameter (φA) of the intersecting portion (particularly, the dimensional measurement by a contact type measuring instrument) is complicated, the rising flow rate is concerned. There was a problem that it was difficult to manage.

このような問題に対し、着座面部１４ａと曲面部１４ｂ（上側テーパ面部１４ｂａ）との間に、昇降方向（中心軸線Ｏ方向）で外径が一定のストレート部を設け、そのストレート部によって寸法測定を簡略化することが既に検討されているが、かかる対策のみでは、流量変化のない領域が発生するため、分解能（特に、低流量域での分解能）が低下してしまうという懸念がある。 To solve such a problem, a straight portion having a constant outer diameter in the elevating direction (center axis O direction) is provided between the seating surface portion 14a and the curved surface portion 14b (upper tapered surface portion 14ba), and the dimension is measured by the straight portion. Although it has already been studied to simplify the above, there is a concern that the resolution (particularly, the resolution in the low flow rate region) will be lowered because a region where the flow rate does not change is generated only by such a measure.

また、前記着座面部１４ａと曲面部１４ｂ（上側テーパ面部１４ｂａ）との交差部分や前記着座面部１４ａとストレート部との交差部分には、加工上、角Ｒが発生し、このような角Ｒでの着座を回避するために、前記弁口４６の最狭部４６ｓの口径に対して前記曲面部１４ｂや前記ストレート部の外径を比較的小さく設定する必要があり、その結果、立上り流量の低減が不十分となってしまうという懸念もある。 Further, an angle R is generated in the intersecting portion between the seating surface portion 14a and the curved surface portion 14b (upper tapered surface portion 14ba) and the intersecting portion between the seating surface portion 14a and the straight portion due to processing. It is necessary to set the outer diameters of the curved surface portion 14b and the straight portion to be relatively small with respect to the diameter of the narrowest portion 46s of the valve opening 46, and as a result, the rising flow rate is reduced. There is also a concern that it will be insufficient.

本発明は、前記課題に鑑みてなされたものであって、その目的とするところは、立上り流量の管理を簡略化しつつ、立上り流量を十分に低減でき、低流量域での制御性を効果的に向上させることのできる電動弁を提供することにある。 The present invention has been made in view of the above problems, and an object of the present invention is to simplify the management of the rising flow rate, sufficiently reduce the rising flow rate, and effectively controllability in a low flow rate range. The purpose is to provide an electric valve that can be improved.

上記する課題を解決するために、本発明に係る電動弁は、基本的に、弁室及び弁座付き弁口を有する弁本体と、リフト量に応じて前記弁口を流れる冷媒の流量を変化させる弁体とを備え、前記弁体には、前記弁座に着接する着座面部と、該着座面部の先端側に連なる、昇降方向で外径が一定の弁体側ストレート部と、該弁体側ストレート部の先端側に連なる、曲率ないし制御角が先端に近づくに従って連続的又は段階的に大きくされた曲面部とが設けられ、前記弁口には、前記弁体側ストレート部より大径の円筒面から構成される最狭部が設けられ、前記弁座の内径が前記最狭部の内径より大きくされ、前記弁口における前記弁座と前記最狭部との間の部分が、前記最狭部側に行くに従って内径が連続的に小さくされた縮径部とされるとともに、前記着座面部、前記縮径部、及び前記曲面部は、前記弁体の中心軸線に対する傾きがその順番で大きくされ、前記弁座が前記弁本体に一体的に形成されていることを特徴としている。 In order to solve the above-mentioned problems, the electric valve according to the present invention basically changes the flow rate of the refrigerant flowing through the valve port and the valve body having the valve chamber and the valve port with the valve seat according to the lift amount. The valve body is provided with a seating surface portion that comes into contact with the valve seat, a valve body side straight portion that is connected to the tip end side of the seating surface portion and has a constant outer diameter in the ascending / descending direction, and a valve body side straight portion. A curved surface portion that is connected to the tip end side and is continuously or stepwise increased as the curvature or control angle approaches the tip end is provided, and the valve port is composed of a cylindrical surface having a diameter larger than that of the valve body side straight portion. The narrowest portion is provided, the inner diameter of the valve seat is made larger than the inner diameter of the narrowest portion, and the portion between the valve seat and the narrowest portion at the valve opening is on the narrowest portion side. with the inner diameter is continuously reduced by a reduced diameter portion toward said seating surface portion, said reduced diameter portion, and said curved surface portion has an inclination with respect to the center axis of the valve body is larger in that order, the valve The seat is integrally formed with the valve body .

他の好ましい態様では、前記着座面部が前記弁座に着座したときに、前記弁体側ストレート部の下端部が前記最狭部の上端部に対応する位置に位置せしめられる。 In another preferred embodiment, when the seating surface portion is seated on the valve seat, the lower end portion of the valve body side straight portion is positioned at a position corresponding to the upper end portion of the narrowest portion.

他の好ましい態様では、前記着座面部が前記弁座に着座したときに、前記弁体側ストレート部の下端部が前記最狭部の上端部より下側に位置せしめられる。 In another preferred embodiment, when the seating surface portion is seated on the valve seat, the lower end portion of the valve body side straight portion is positioned below the upper end portion of the narrowest portion.

本発明によれば、弁本体の弁口に、弁体側ストレート部より大径の最狭部が設けられ、弁座の内径がその最狭部の内径より大きくされている。そのため、着座部分と立上り流量の制御部分とが別の位置に設定されることになるので、例えば弁座の内径と最狭部の内径とが同径とされた従来の電動弁と比べて、立上り流量の管理を簡略化しつつ、立上り流量を十分に低減でき、低流量域での制御性を効果的に向上させることができる。 According to the present invention, the valve opening of the valve body is provided with a narrowest portion having a diameter larger than that of the straight portion on the valve body side, and the inner diameter of the valve seat is made larger than the inner diameter of the narrowest portion. Therefore, the seating portion and the rising flow rate control portion are set at different positions. Therefore, as compared with a conventional electric valve in which the inner diameter of the valve seat and the inner diameter of the narrowest portion are the same, for example. While simplifying the management of the rising flow rate, the rising flow rate can be sufficiently reduced, and the controllability in the low flow rate range can be effectively improved.

本発明に係る電動弁の一実施形態を示す縦断面図。The vertical sectional view which shows one Embodiment of the electric valve which concerns on this invention. 図１に示される電動弁の要部を拡大して示す要部拡大縦断面図。An enlarged vertical cross-sectional view of a main part of the electric valve shown in FIG. 1 in an enlarged manner. 図１に示される電動弁の流量特性を示す図。The figure which shows the flow rate characteristic of the electric valve shown in FIG. 図１に示される電動弁の他例の要部を拡大して示す要部拡大縦断面図。An enlarged vertical cross-sectional view of a main part of another example of the electric valve shown in FIG. 1 in an enlarged manner. 図１に示される電動弁の更なる他例の要部を拡大して示す要部拡大縦断面図。An enlarged vertical cross-sectional view of a main part of the electric valve shown in FIG. 1 in which a main part of another example is enlarged. 図５に示される電動弁の流量特性を示す図。The figure which shows the flow rate characteristic of the electric valve shown in FIG. 従来の電動弁の要部を拡大して示す要部拡大縦断面図。An enlarged vertical sectional view of a main part of a conventional electric valve in an enlarged manner.

以下、本発明の実施形態を図面を参照しながら説明する。なお、各図において、部材間に形成される隙間や部材間の離隔距離等は、発明の理解を容易にするため、また、作図上の便宜を図るため、誇張して描かれている場合がある。また、本明細書において、上下、左右等の位置、方向を表わす記述は、図１の方向矢印表示を基準としており、実際の使用状態での位置、方向を指すものではない。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each drawing, the gaps formed between the members, the separation distance between the members, etc. may be exaggerated in order to facilitate understanding of the invention and for convenience in drawing. is there. Further, in the present specification, the description indicating the position and direction such as up and down, left and right, etc. is based on the direction arrow display of FIG. 1, and does not indicate the position and direction in the actual use state.

図１は、本発明に係る電動弁の一実施形態を示す縦断面図である。 FIG. 1 is a vertical cross-sectional view showing an embodiment of an electric valve according to the present invention.

図示実施形態の電動弁１は、例えばヒートポンプ式冷暖房システム等において冷媒流量を調整するために使用されるもので、主に、弁体１４を有する弁軸１０と、ガイドブッシュ２０と、弁軸ホルダ３０と、弁本体４０と、キャン５５と、ロータ５１とステータ５２とからなるステッピングモータ５０と、圧縮コイルばね６０と、抜け止め係止部材７０と、ねじ送り機構２８と、下部ストッパ機構２９とを備える。 The electric valve 1 of the illustrated embodiment is used for adjusting the flow rate of the refrigerant in, for example, a heat pump type heating / cooling system, and mainly includes a valve shaft 10 having a valve body 14, a guide bush 20, and a valve shaft holder. 30, a valve body 40, a can 55, a stepping motor 50 including a rotor 51 and a stator 52, a compression coil spring 60, a retaining locking member 70, a screw feed mechanism 28, and a lower stopper mechanism 29. To be equipped.

前記弁軸１０は、上側から、上部小径部１１と、中間大径部１２と、下部小径部１３とを有し、その下部小径部１３の下端部に、弁口４６を流れる流体（冷媒）の通過流量を制御するための弁体１４が一体的に形成されている。 The valve shaft 10 has an upper small diameter portion 11, an intermediate large diameter portion 12, and a lower small diameter portion 13 from the upper side, and a fluid (refrigerant) flowing through the valve port 46 at the lower end portion of the lower small diameter portion 13. A valve body 14 for controlling the passing flow rate of the valve body 14 is integrally formed.

前記弁体１４は、図１とともに図２を参照すればよく分かるように、上側（弁室４０ａ側）から、弁座４６ａに着接（着座）する逆円錐台面からなる着座面部１４ａと、該着座面部１４ａの下側に連なる、弁軸１０の下部小径部１３より若干小径の円筒面（昇降方向で外径が一定）からなるストレート部（弁体側ストレート部）１４ｓと、該ストレート部１４ｓの下側に連なる、弁座４６ａからのリフト量に応じて弁口４６を流れる流体の流量を変化させるための曲面部１４ｂとを有する。曲面部１４ｂは、先端に近づくに従って制御角（弁体１４の中心軸線Ｏと平行な線との交差角）が段階的に大きくされた複数段（ここでは２段）の逆円錐台状のテーパ面部を有する。ここでは、前記複数段（２段）の逆円錐台状のテーパ面部は、逆円錐台面からなる上側テーパ面部１４ｂａと、上側テーパ面部１４ｂａより制御角が大きい逆円錐台面からなる下側テーパ面部１４ｂｂとを有している。 As can be clearly seen by referring to FIG. 2 together with FIG. 1, the valve body 14 has a seating surface portion 14a formed of an inverted conical base surface that is attached (seat) to the valve seat 46a from the upper side (valve chamber 40a side) and the seating surface portion 14a. A straight portion (valve body side straight portion) 14s formed of a cylindrical surface (outer diameter is constant in the elevating direction) slightly smaller than the lower small diameter portion 13 of the valve shaft 10 connected to the lower side of the seating surface portion 14a, and the straight portion 14s. It has a curved surface portion 14b connected to the lower side for changing the flow rate of the fluid flowing through the valve port 46 according to the amount of lift from the valve seat 46a. The curved surface portion 14b is a multi-stage (here, two-stage) inverted truncated cone-shaped taper in which the control angle (intersection angle between the central axis O of the valve body 14 and the line parallel to the valve body 14) is gradually increased as it approaches the tip. It has a face portion. Here, the plurality of stages (two stages) of the inverted truncated cone-shaped tapered surface portion is a lower tapered surface portion 14bb composed of an upper tapered surface portion 14ba made of an inverted truncated cone surface and an inverted truncated cone surface having a larger control angle than the upper tapered surface portion 14ba. And have.

前記ガイドブッシュ２０は、前記弁軸１０（の中間大径部１２）が軸線Ｏ方向に相対移動（摺動）可能及び軸線Ｏ回りに相対回転可能な状態で内挿される円筒部２１と、該円筒部２１の上端部から上方に延びており、該円筒部２１よりも内径が大きく、前記弁軸１０の中間大径部１２の上端側と上部小径部１１の下端側とが内挿される延設部２２とを有している。前記ガイドブッシュ２０の円筒部２１の外周には、ロータ５１の回転駆動に応じて前記弁軸１０の弁体１４を弁本体４０の弁座４６ａに対して昇降させるねじ送り機構２８の一方を構成する固定ねじ部（雄ねじ部）２３が形成されている。また、前記円筒部２１の下部（固定ねじ部２３より下側の部分）は、大径とされ、弁本体４０の嵌合穴４４への嵌合部２７とされる。前記固定ねじ部２３（における弁軸ホルダ３０より下側）には、下部ストッパ２５が螺着されて固定されており、その下部ストッパ２５の外周には、弁軸ホルダ３０（すなわち、弁軸ホルダ３０に連結された弁軸１０）の回転下動規制を行う下部ストッパ機構２９の一方を構成する固定ストッパ体２４が一体的に突設されている。なお、嵌合部２７の上面２７ａは、下部ストッパ２５の下動規制を行う（言い換えれば、下部ストッパ２５の下動限界位置もしくは最下動位置を規定する）ストッパ部とされる。 The guide bush 20 includes a cylindrical portion 21 inserted in a state in which the valve shaft 10 (intermediate large diameter portion 12) is relatively movable (sliding) in the axis O direction and relatively rotatable around the axis O. It extends upward from the upper end of the cylindrical portion 21, has an inner diameter larger than that of the cylindrical portion 21, and is inserted into the upper end side of the intermediate large diameter portion 12 of the valve shaft 10 and the lower end side of the upper small diameter portion 11. It has a setting part 22 and. On the outer circumference of the cylindrical portion 21 of the guide bush 20, one of the screw feed mechanisms 28 that raises and lowers the valve body 14 of the valve shaft 10 with respect to the valve seat 46a of the valve body 40 according to the rotational drive of the rotor 51 is configured. A fixing screw portion (male screw portion) 23 is formed. Further, the lower portion of the cylindrical portion 21 (the portion below the fixing screw portion 23) has a large diameter, and is a fitting portion 27 into the fitting hole 44 of the valve body 40. A lower stopper 25 is screwed and fixed to the fixing screw portion 23 (below the valve shaft holder 30 in the fixing screw portion 23), and the valve shaft holder 30 (that is, the valve shaft holder 30) is fixed to the outer periphery of the lower stopper 25. A fixed stopper body 24 constituting one of the lower stopper mechanisms 29 that regulates the rotational downward movement of the valve shaft 10) connected to the 30) is integrally projected. The upper surface 27a of the fitting portion 27 is a stopper portion that regulates the downward movement of the lower stopper 25 (in other words, defines the lower movement limit position or the lowest movement position of the lower stopper 25).

前記弁軸ホルダ３０は、前記ガイドブッシュ２０が内挿される円筒部３１と前記弁軸１０（の上部小径部１１）の上端部が挿通される挿通穴３２ａが貫設された天井部３２とを有している。前記弁軸ホルダ３０の円筒部３１の内周には、前記ガイドブッシュ２０の固定ねじ部２３と螺合して前記ねじ送り機構２８を構成する可動ねじ部（雌ねじ部）３３が形成されると共に、その円筒部３１の外周下端には、前記下部ストッパ機構２９の他方を構成する可動ストッパ体３４が一体的に突設されている。 The valve shaft holder 30 has a cylindrical portion 31 into which the guide bush 20 is inserted and a ceiling portion 32 through which an insertion hole 32a through which the upper end portion of the valve shaft 10 (upper small diameter portion 11) is inserted is inserted. Have. A movable screw portion (female screw portion) 33 that is screwed with the fixing screw portion 23 of the guide bush 20 to form the screw feed mechanism 28 is formed on the inner circumference of the cylindrical portion 31 of the valve shaft holder 30. A movable stopper body 34 constituting the other side of the lower stopper mechanism 29 is integrally projected from the lower end of the outer periphery of the cylindrical portion 31.

また、前記弁軸１０の上部小径部１１と中間大径部１２との間に形成された段丘面と前記弁軸ホルダ３０の天井部３２の下面との間には、弁軸１０の上部小径部１１に外挿されるように、前記弁軸１０と前記弁軸ホルダ３０とが昇降方向（軸線Ｏ方向）で離れる方向に付勢する、言い換えれば前記弁軸１０（弁体１４）を常時下方（閉弁方向）に付勢する圧縮コイルばね６０が縮装されている。 Further, between the terrace surface formed between the upper small diameter portion 11 of the valve shaft 10 and the intermediate large diameter portion 12 and the lower surface of the ceiling portion 32 of the valve shaft holder 30, the upper small diameter of the valve shaft 10 is formed. The valve shaft 10 and the valve shaft holder 30 are urged in a direction away from each other in the elevating direction (axis O direction) so as to be externally inserted into the portion 11, in other words, the valve shaft 10 (valve body 14) is always downward. The compression coil spring 60 urging in the (valve closing direction) is compressed.

前記弁本体４０は、例えば真鍮やＳＵＳ等の金属製円筒体から構成されている。この弁本体４０は、内部に流体が導入導出される弁室４０ａを有し、該弁室４０ａの側部に設けられた横向きの第１開口４１に第１導管４１ａがろう付け等により連結固定され、該弁室４０ａの天井部に前記弁軸１０（の中間大径部１２）が軸線Ｏ方向に相対移動（摺動）可能及び軸線Ｏ回りに相対回転可能な状態で挿通される挿通穴４３及び前記ガイドブッシュ２０の下部（嵌合部２７）が嵌合されて取付固定される嵌合穴４４が形成され、該弁室４０ａの下部に設けられた縦向きの第２開口４２に第２導管４２ａがろう付け等により連結固定されている。また、前記弁室４０ａと前記第２開口４２との間に設けられた底部壁からなる弁シート部４５に、前記弁体１４が接離する弁座４６ａを有する弁口４６が形成されている。 The valve body 40 is made of a metal cylinder such as brass or SUS. The valve body 40 has a valve chamber 40a into which a fluid is introduced and led out, and a first conduit 41a is connected and fixed to a lateral first opening 41 provided on a side portion of the valve chamber 40a by brazing or the like. An insertion hole is inserted into the ceiling of the valve chamber 40a so that the valve shaft 10 (intermediate large diameter portion 12) can move (slide) relative to the axis O and can rotate relative to the axis O. A fitting hole 44 is formed by fitting the lower portion (fitting portion 27) of the guide bush 20 and the guide bush 20 to be mounted and fixed, and the second opening 42 in the vertical direction provided in the lower portion of the valve chamber 40a has a second opening. 2 The conduit 42a is connected and fixed by brazing or the like. Further, a valve port 46 having a valve seat 46a with which the valve body 14 is brought into contact with and separated from the valve body 14 is formed in a valve seat portion 45 formed of a bottom wall provided between the valve chamber 40a and the second opening 42. ..

前記弁口４６は、図１とともに図２を参照すればよく分かるように、上側（弁室４０ａ側）から、弁座４６ａに連なる、下側（最狭部４６ｓ側）に行くに従って内径が連続的に小さくされた逆立円錐台面からなる縮径部４６ｂと、該縮径部４６ｂの下側に連なる、円筒面（昇降方向で内径が一定）からなる最狭部（弁口４６において最も口径が小さくされた部分）４６ｓと、該最狭部４６ｓの下側に連なる、下側に行くに従って内径が連続的に大きくされた円錐台面からなる拡径部４６ｃとを有する。 As can be clearly seen by referring to FIG. 2 together with FIG. 1, the inner diameter of the valve port 46 is continuous from the upper side (valve chamber 40a side) to the lower side (narrowest portion 46s side) connected to the valve seat 46a. The narrowest part (the smallest diameter in the valve opening 46) consisting of a reduced diameter portion 46b made of an inverted conical base surface reduced in size and a cylindrical surface (inner diameter is constant in the ascending / descending direction) connected to the lower side of the reduced diameter portion 46b. 46s) and a diameter-expanded portion 46c formed of a conical base surface which is continuous with the lower side of the narrowest portion 46s and whose inner diameter is continuously increased toward the lower side.

前記弁座４６ａの内径（口径）（φＣ）は、前記弁軸１０の下部小径部１３より小径に設計され、前記最狭部４６ｓの内径（口径）（φＢ）は、前記弁体１４のストレート部１４ｓの外径（φＡ）より若干大径に設計されており、弁座４６ａの内径（φＣ）は、最狭部４６ｓの内径（φＢ）より大きくされている。 The inner diameter (caliber) (φC) of the valve seat 46a is designed to be smaller than the lower small diameter portion 13 of the valve shaft 10, and the inner diameter (caliber) (φB) of the narrowest portion 46s is straight of the valve body 14. The diameter is designed to be slightly larger than the outer diameter (φA) of the portion 14s, and the inner diameter (φC) of the valve seat 46a is larger than the inner diameter (φB) of the narrowest portion 46s.

また、ここでは、弁体１４の着座面部１４ａが弁座４６ａに着座したときに、ストレート部１４ｓの下端部と最狭部４６ｓの上端部とが略同じ位置になるように、各部の寸法形状が設定されている（図１及び図２に示される状態）。 Further, here, when the seating surface portion 14a of the valve body 14 is seated on the valve seat 46a, the dimensional shape of each portion is such that the lower end portion of the straight portion 14s and the upper end portion of the narrowest portion 46s are at substantially the same position. Is set (the state shown in FIGS. 1 and 2).

一方、前記弁本体４０の上端部には鍔状板４７がかしめ等により固着されると共に、該鍔状板４７の外周に設けられた段差部に、天井付き円筒状のキャン５５の下端部が突き合わせ溶接により密封接合されている。 On the other hand, the flange-shaped plate 47 is fixed to the upper end of the valve body 40 by caulking or the like, and the lower end of the cylindrical can 55 with a ceiling is attached to the stepped portion provided on the outer periphery of the flange-shaped plate 47. It is sealed and joined by butt welding.

前記キャン５５の内側かつ前記ガイドブッシュ２０及び前記弁軸ホルダ３０の外側には、ロータ５１が回転自在に配在され、前記キャン５５の外側に、前記ロータ５１を回転駆動すべく、ヨーク５２ａ、ボビン５２ｂ、ステータコイル５２ｃ、及び樹脂モールドカバー５２ｄ等からなるステータ５２が配置されている。ステータコイル５２ｃには、複数のリード端子５２ｅが接続され、これらのリード端子５２ｅには、基板５２ｆを介して複数のリード線５２ｇが接続され、ステータコイル５２ｃへの通電励磁によってキャン５５内に配在されたロータ５１が軸線Ｏ回りで回転するようになっている。 A rotor 51 is rotatably arranged inside the can 55 and outside the guide bush 20 and the valve shaft holder 30, and a yoke 52a, A stator 52 composed of a bobbin 52b, a stator coil 52c, a resin mold cover 52d, and the like is arranged. A plurality of lead terminals 52e are connected to the stator coil 52c, and a plurality of lead wires 52g are connected to these lead terminals 52e via the substrate 52f and arranged in the can 55 by energizing the stator coil 52c. The existing rotor 51 rotates around the axis O.

キャン５５内に配在された前記ロータ５１は、前記弁軸ホルダ３０に係合支持されており、当該弁軸ホルダ３０は前記ロータ５１とともに（一体に）回転するようになっている。 The rotor 51 arranged in the can 55 is engaged and supported by the valve shaft holder 30, and the valve shaft holder 30 rotates (integrally) with the rotor 51.

詳細には、前記ロータ５１は、内筒５１ａ、外筒５１ｂ、及び内筒５１ａと外筒５１ｂとを軸線Ｏ回りの所定の角度位置で接続する接続部５１ｃからなる二重管構成とされ、内筒５１ａの内周に、（例えば、軸線Ｏ回りで１２０度の角度間隔で）軸線Ｏ方向（上下方向）に延びる縦溝５１ｄが形成されている。 Specifically, the rotor 51 has a double pipe configuration including an inner cylinder 51a, an outer cylinder 51b, and a connecting portion 51c that connects the inner cylinder 51a and the outer cylinder 51b at a predetermined angle position around the axis O. A vertical groove 51d extending in the axis O direction (vertical direction) is formed on the inner circumference of the inner cylinder 51a (for example, at an angle interval of 120 degrees around the axis O).

一方、前記弁軸ホルダ３０の外周（の上半部分）には、（例えば、軸線Ｏ回りで１２０度の角度間隔で）上下方向に延びる突条３０ａが突設され、その突条３０ａの下部両側には、前記ロータ５１を支持する上向きの係止面（不図示）が形成されている。 On the other hand, on the outer circumference (upper half portion) of the valve shaft holder 30, a ridge 30a extending in the vertical direction (for example, at an angle interval of 120 degrees around the axis O) is projected, and a lower portion of the ridge 30a is provided. On both sides, upward locking surfaces (not shown) that support the rotor 51 are formed.

ロータ５１の内筒５１ａの縦溝５１ｄと弁軸ホルダ３０の突条３０ａとが係合し、かつロータ５１の内筒５１ａの下面と弁軸ホルダ３０の係止面とが当接することにより、ロータ５１が弁軸ホルダ３０に対して位置合わせされた状態で支持固定され、前記弁軸ホルダ３０は、前記ロータ５１を前記キャン５５内で支持しながら当該ロータ５１と共に回転される。 The vertical groove 51d of the inner cylinder 51a of the rotor 51 and the ridge 30a of the valve shaft holder 30 are engaged with each other, and the lower surface of the inner cylinder 51a of the rotor 51 and the locking surface of the valve shaft holder 30 are in contact with each other. The rotor 51 is supported and fixed in a state of being aligned with the valve shaft holder 30, and the valve shaft holder 30 is rotated together with the rotor 51 while supporting the rotor 51 in the can 55.

前記ロータ５１及び弁軸ホルダ３０の上側には、弁軸ホルダ３０とロータ５１との昇降方向における相対移動を防止する（言い換えれば、弁軸ホルダ３０に対してロータ５１を下方に押し付ける）と共に弁軸１０と弁軸ホルダ３０とを連結すべく、前記弁軸１０（の上部小径部１１）の上端部に圧入・溶接等により外嵌固定されたプッシュナット７１と、該プッシュナット７１とロータ５１との間に介在され、弁軸１０の上端部が挿通される挿通穴７２ａが中央に形成された円板状部材からなるロータ押さえ７２とから構成される抜け止め係止部材７０が配在されている。すなわち、前記ロータ５１は、圧縮コイルばね６０の付勢力により上方に付勢される弁軸ホルダ３０と前記ロータ押さえ７２との間で挟持されている。なお、弁軸ホルダ３０の上端から係止面までの（上下方向の）高さは、ロータ５１の内筒５１ａの（上下方向の）高さと同じであり、弁軸ホルダ３０（の天井部３２）の上面は、前記ロータ押さえ７２の下面（平坦面）と当接している。 On the upper side of the rotor 51 and the valve shaft holder 30, the valve is prevented from moving relative to the valve shaft holder 30 and the rotor 51 in the ascending / descending direction (in other words, the rotor 51 is pressed downward against the valve shaft holder 30). A push nut 71 that is externally fitted and fixed to the upper end of the valve shaft 10 (upper small diameter portion 11) by press fitting, welding, or the like in order to connect the shaft 10 and the valve shaft holder 30, and the push nut 71 and the rotor 51. A retaining locking member 70 composed of a rotor retainer 72 made of a disk-shaped member having an insertion hole 72a formed in the center through which the upper end portion of the valve shaft 10 is inserted is arranged. ing. That is, the rotor 51 is sandwiched between the valve shaft holder 30 that is urged upward by the urging force of the compression coil spring 60 and the rotor retainer 72. The height (vertical direction) from the upper end of the valve shaft holder 30 to the locking surface is the same as the height (vertical direction) of the inner cylinder 51a of the rotor 51, and the valve shaft holder 30 (ceiling portion 32). ) Is in contact with the lower surface (flat surface) of the rotor retainer 72.

また、前記弁軸１０の上端部に固定された前記プッシュナット７１には、動作時にガイドブッシュ２０に対して弁軸ホルダ３０が上方に移動し過ぎて、ガイドブッシュ２０の固定ねじ部２３と弁軸ホルダ３０の可動ねじ部３３との螺合が外れるのを防止すべく、弁軸ホルダ３０をガイドブッシュ２０側に付勢するコイルばねからなる復帰ばね７５が外装されている。 Further, the valve shaft holder 30 moves too much upward with respect to the guide bush 20 to the push nut 71 fixed to the upper end portion of the valve shaft 10, and the fixing screw portion 23 of the guide bush 20 and the valve. In order to prevent the shaft holder 30 from being screwed off from the movable screw portion 33, a return spring 75 made of a coil spring that urges the valve shaft holder 30 toward the guide bush 20 is externally provided.

かかる構成の電動弁１では、ステータ５２（のステータコイル５２ｃ）への通電励磁によってロータ５１が回転せしめられると、それと一体に弁軸ホルダ３０及び弁軸１０が回転せしめられる。このとき、ガイドブッシュ２０の固定ねじ部２３と弁軸ホルダ３０の可動ねじ部３３とからなるねじ送り機構２８により、弁軸１０が弁体１４を伴って昇降せしめられ、これによって、弁体１４と弁座４６ａとの間の間隙（リフト量、弁開度）が増減されて、冷媒等の流体の通過流量が調整される（図３参照）。また、弁軸ホルダ３０の可動ストッパ体３４とガイドブッシュ２０に固定された下部ストッパ２５の固定ストッパ体２４とが当接し、弁体１４が最下降位置にあるとき（弁体１４のリフト量が０のとき）には、弁体１４（の着座面部１４ａ）が弁座４６ａに着座して弁口４６が閉じられた全閉状態とされ、弁口４６における冷媒等の流体の流れが遮断される（図１及び図２に示される状態）。 In the electric valve 1 having such a configuration, when the rotor 51 is rotated by energizing the stator 52 (stator coil 52c), the valve shaft holder 30 and the valve shaft 10 are rotated integrally with the rotor 51. At this time, the valve shaft 10 is moved up and down with the valve body 14 by the screw feed mechanism 28 including the fixed screw portion 23 of the guide bush 20 and the movable screw portion 33 of the valve shaft holder 30, thereby causing the valve body 14 to move up and down. The gap (lift amount, valve opening degree) between the valve seat 46a and the valve seat 46a is increased or decreased to adjust the passing flow rate of a fluid such as a refrigerant (see FIG. 3). Further, when the movable stopper body 34 of the valve shaft holder 30 and the fixed stopper body 24 of the lower stopper 25 fixed to the guide bush 20 are in contact with each other and the valve body 14 is in the lowest position (the lift amount of the valve body 14 is increased). (When 0), the valve body 14 (seat surface portion 14a) is seated on the valve seat 46a, and the valve port 46 is closed to a fully closed state, so that the flow of fluid such as refrigerant in the valve port 46 is blocked. (The state shown in FIGS. 1 and 2).

ここで、本実施形態では、弁口４６における弁座４６ａの内径（口径）が最狭部４６ｓの内径（口径）より大きくされるとともに、弁体１４の着座面部１４ａが弁座４６ａに着座したとき（つまり、弁体１４が最下降位置にあるとき）に、ストレート部１４ｓの下端部が最狭部４６ｓの上端部に対応する位置に位置せしめられる。そのため、弁体１４が昇降せしめられて、弁体１４の着座面部１４ａが弁座４６ａ（言い換えれば、縮径部４６ｂの上端部分）から離れた直後（開弁直後）に（図３の点Ｄにおける状態）、弁体１４の曲面部１４ｂ（の上側テーパ面部１４ｂａ）と弁口４６の最狭部４６ｓ（の上端部）（言い換えれば、縮径部４６ｂの下端部分）との間で、立上り流量の制御が行われることになる。 Here, in the present embodiment, the inner diameter (caliber) of the valve seat 46a at the valve opening 46 is made larger than the inner diameter (caliber) of the narrowest portion 46s, and the seating surface portion 14a of the valve body 14 is seated on the valve seat 46a. At times (that is, when the valve body 14 is in the lowest position), the lower end of the straight portion 14s is positioned at a position corresponding to the upper end of the narrowest portion 46s. Therefore, immediately after the valve body 14 is moved up and down and the seating surface portion 14a of the valve body 14 separates from the valve seat 46a (in other words, the upper end portion of the reduced diameter portion 46b) (immediately after the valve opening) (point D in FIG. 3). In the state), the rising edge between the curved surface portion 14b (upper tapered surface portion 14ba) of the valve body 14 and the narrowest portion 46s (upper end portion) of the valve opening 46 (in other words, the lower end portion of the reduced diameter portion 46b). The flow rate will be controlled.

このように、本実施形態においては、着座部分と立上り流量の制御部分とが別の位置に設定されることになるので、例えば弁座の内径と最狭部の内径とが同径とされた従来の電動弁と比べて、立上り流量の管理を簡略化しつつ、立上り流量を十分に低減でき、低流量域での制御性を効果的に向上させることができる。 As described above, in the present embodiment, the seating portion and the rising flow rate control portion are set at different positions. Therefore, for example, the inner diameter of the valve seat and the inner diameter of the narrowest portion are set to be the same diameter. Compared with the conventional electric valve, the rising flow rate can be sufficiently reduced while simplifying the management of the rising flow rate, and the controllability in the low flow rate range can be effectively improved.

また、本実施形態においては、着座部分（弁体１４の着座面部１４ａと弁座４６ａとが当接する部分）が（着座面部１４ａとストレート部１４ｓとの交差部分に形成される）角Ｒから離れた位置に設定されることになるので、最狭部４６ｓの内径（φＢ）をストレート部１４ｓの外径（φＡ）とほぼ同じに設定できるため、この点からも、立上り流量を十分に低減でき、低流量域での制御性を効果的に向上させることが可能となる。 Further, in the present embodiment, the seating portion (the portion where the seating surface portion 14a of the valve body 14 and the valve seat 46a abut) is separated from the angle R (formed at the intersection of the seating surface portion 14a and the straight portion 14s). Since the position is set to the same position, the inner diameter (φB) of the narrowest portion 46s can be set to be almost the same as the outer diameter (φA) of the straight portion 14s, and the rising flow rate can be sufficiently reduced from this point as well. , It is possible to effectively improve the controllability in the low flow rate range.

なお、上記実施形態では、弁口４６における弁座４６ａと最狭部４６ｓとの間の縮径部４６ｂが弁体１４における曲面部１４ｂ（の上側テーパ面部１４ｂａ）と平行に設定されていない（図示例では、縮径部４６ｂの中心軸線Ｏに対する傾きが曲面部１４ｂ（の上側テーパ面部１４ｂａ）の中心軸線Ｏに対する傾きより大きい）ために、低流量域（弁開度が小さい領域）における流量特性に変曲点（図３の点Ｅ）が存在するが、弁口４６における縮径部４６ｂを弁体１４における曲面部１４ｂ（の上側テーパ面部１４ｂａ）と平行に設定することで、低流量域における流量特性を連続的に（変曲点が無く）設定できる（例えば、図３の一点鎖線で示される流量特性となる）ため、中間開度での流量ばらつきを抑えることが可能となる。 In the above embodiment, the reduced diameter portion 46b between the valve seat 46a and the narrowest portion 46s in the valve opening 46 is not set parallel to the curved surface portion 14b (upper tapered surface portion 14ba) in the valve body 14. In the illustrated example, since the inclination of the reduced diameter portion 46b with respect to the central axis O is larger than the inclination of the curved surface portion 14b (upper tapered surface portion 14ba) with respect to the central axis O), the flow rate in the low flow rate region (region where the valve opening is small). Although there is a bending point (point E in FIG. 3) in the characteristics, a low flow rate is achieved by setting the reduced diameter portion 46b at the valve port 46 in parallel with the curved surface portion 14b (upper tapered surface portion 14ba) of the valve body 14. Since the flow rate characteristics in the region can be set continuously (without any bending point) (for example, the flow rate characteristics shown by the one-point chain line in FIG. 3), it is possible to suppress the flow rate variation at the intermediate opening degree.

なお、上記実施形態では、弁口４６における弁座４６ａと最狭部４６ｓとの間の部分が、下側に行くに従って内径が連続的に小さくされた逆立円錐台面からなる縮径部４６ｂとされているが、例えば図４に示される如くに、下側に行くに従って内径が段階的に小さくされた段差部（図４に示す例では、１段の段差部）としてもよい。 In the above embodiment, the portion of the valve opening 46 between the valve seat 46a and the narrowest portion 46s has a diameter-reduced portion 46b formed of an inverted conical base surface whose inner diameter is continuously reduced toward the lower side. However, as shown in FIG. 4, for example, a step portion whose inner diameter is gradually reduced toward the lower side (in the example shown in FIG. 4, one step portion) may be used.

また、上記実施形態では、弁体１４の着座面部１４ａが弁座４６ａに着座したときに、ストレート部１４ｓの下端部が最狭部４６ｓの上端部に対応する位置に位置せしめられるが、各部品の寸法ばらつき等を考慮すると、例えば図５に示される如くに、弁体１４の着座面部１４ａが弁座４６ａに着座したときに、ストレート部１４ｓの下端部が最狭部４６ｓの上端部より（例えば昇降方向でＧ分だけ）下側に位置せしめられるように、各部の寸法形状を設定しておく、言い換えれば、ストレート部１４ｓの下側部分と最狭部４６ｓの上側部分とが例えば昇降方向（上下方向）でＧ分だけ重なる（ラップする）ようにしておくことが好ましい。この場合、図６に示される如くに、流量特性において流量変化のない領域が僅かに発生することになる。 Further, in the above embodiment, when the seating surface portion 14a of the valve body 14 is seated on the valve seat 46a, the lower end portion of the straight portion 14s is positioned at a position corresponding to the upper end portion of the narrowest portion 46s. When the seating surface portion 14a of the valve body 14 is seated on the valve seat 46a, the lower end portion of the straight portion 14s is closer to the upper end portion of the narrowest portion 46s, as shown in FIG. For example, the dimensions and shapes of each part are set so that they can be positioned on the lower side (for example, by G in the vertical direction), in other words, the lower part of the straight portion 14s and the upper portion of the narrowest portion 46s are, for example, in the vertical direction. It is preferable to overlap (wrap) by G in the (vertical direction). In this case, as shown in FIG. 6, a region where the flow rate does not change is slightly generated in the flow rate characteristics.

また、上記実施形態では、弁体１４における曲面部１４ｂが、先端側ほど制御角が段階的に大きくされた複数段の逆円錐台状のテーパ面部（上側テーパ面部１４ｂａ及び下側テーパ面部１４ｂｂ）で構成されているが、これに限られる訳ではなく、先端に近づくに従って曲率が連続的に大きくされた楕球面部、あるいは、該楕球面部と一段もしくは複数段の逆円錐台状のテーパ面部との組み合わせ等により構成してもよいことは勿論である。 Further, in the above embodiment, the curved surface portion 14b of the valve body 14 has a plurality of steps of inverted truncated cone-shaped tapered surface portions (upper tapered surface portion 14ba and lower tapered surface portion 14bb) in which the control angle is gradually increased toward the tip end side. However, it is not limited to this, and it is an elliptical spherical surface portion whose curvature is continuously increased as it approaches the tip, or an inverted truncated cone-shaped tapered surface portion having one or more steps with the elliptical spherical surface portion. Of course, it may be configured by combining with and the like.

１電動弁
１０弁軸
１４弁体
１４ａ着座面部
１４ｂ曲面部
１４ｂａ上側テーパ面部
１４ｂｂ下側テーパ面部
１４ｓストレート部
２０ガイドブッシュ
２１円筒部
２３固定ねじ部（雄ねじ部）
２８ねじ送り機構
２９下部ストッパ機構
３０弁軸ホルダ
３３可動ねじ部（雌ねじ部）
４０弁本体
４０ａ弁室
４１第１開口
４１ａ第１導管
４２第２開口
４２ａ第２導管
４５弁シート部
４６弁口
４６ａ弁座
４６ｂ縮径部
４６ｃ拡径部
４６ｓ最狭部
４７鍔状部
５０ステッピングモータ
５１ロータ
５２ステータ
５５キャン
６０圧縮コイルばね
７０抜け止め係止部材
Ｏ軸線
φＡストレート部の外径
φＢ最狭部の内径（口径）
φＣ弁座の内径（口径） 1 Electric valve 10 Valve shaft 14 Valve body 14a Seating surface 14b Curved surface 14ba Upper tapered surface 14bb Lower tapered surface 14s Straight 20 Guide bush 21 Cylindrical 23 Fixed thread (male thread)
28 Thread feed mechanism 29 Lower stopper mechanism 30 Valve shaft holder 33 Movable screw part (female thread part)
40 Valve body 40a Valve chamber 41 1st opening 41a 1st conduit 42 2nd opening 42a 2nd conduit 45 Valve seat 46 Valve mouth 46a Valve seat 46b Reduced diameter 46c Expanded diameter 46s Narrowest 47 Flange 50 Stepping Motor 51 Rotor 52 Stator 55 Can 60 Compression coil spring 70 Retaining locking member O Axis line φA Outer diameter of straight part φB Inner diameter (diameter) of narrowest part
φC valve seat inner diameter (caliber)

Claims

弁室及び弁座付き弁口を有する弁本体と、リフト量に応じて前記弁口を流れる冷媒の流量を変化させる弁体とを備える電動弁であって、
前記弁体には、前記弁座に着接する着座面部と、該着座面部の先端側に連なる、昇降方向で外径が一定の弁体側ストレート部と、該弁体側ストレート部の先端側に連なる、曲率ないし制御角が先端に近づくに従って連続的又は段階的に大きくされた曲面部とが設けられ、
前記弁口には、前記弁体側ストレート部より大径の円筒面から構成される最狭部が設けられ、前記弁座の内径が前記最狭部の内径より大きくされ、
前記弁口における前記弁座と前記最狭部との間の部分が、前記最狭部側に行くに従って内径が連続的に小さくされた縮径部とされるとともに、
前記着座面部、前記縮径部、及び前記曲面部は、前記弁体の中心軸線に対する傾きがその順番で大きくされ、
前記弁座が前記弁本体に一体的に形成されていることを特徴とする電動弁。 An electric valve including a valve body having a valve chamber and a valve port with a valve seat, and a valve body that changes the flow rate of the refrigerant flowing through the valve port according to the lift amount.
The valve body includes a seating surface portion that comes into contact with the valve seat, a valve body side straight portion that is connected to the tip end side of the seating surface portion and has a constant outer diameter in the ascending / descending direction, and is connected to the tip end side of the valve body side straight portion. A curved surface portion that is continuously or stepwise increased as the curvature or control angle approaches the tip is provided.
The valve port is provided with a narrowest portion formed of a cylindrical surface having a diameter larger than that of the straight portion on the valve body side, and the inner diameter of the valve seat is made larger than the inner diameter of the narrowest portion.
The portion of the valve opening between the valve seat and the narrowest portion is a reduced diameter portion whose inner diameter is continuously reduced toward the narrowest portion side.
The seating surface portion, the reduced diameter portion, and the curved surface portion are increased in inclination with respect to the central axis of the valve body in that order .
An electric valve characterized in that the valve seat is integrally formed with the valve body.

前記着座面部が前記弁座に着座したときに、前記弁体側ストレート部の下端部が前記最狭部の上端部に対応する位置に位置せしめられていることを特徴とする請求項１に記載の電動弁。 The first aspect of claim 1, wherein when the seating surface portion is seated on the valve seat, the lower end portion of the straight portion on the valve body side is positioned at a position corresponding to the upper end portion of the narrowest portion. Electric valve.

前記着座面部が前記弁座に着座したときに、前記弁体側ストレート部の下端部が前記最狭部の上端部より下側に位置せしめられていることを特徴とする請求項１に記載の電動弁。 The electric motor according to claim 1, wherein the lower end portion of the straight portion on the valve body side is positioned below the upper end portion of the narrowest portion when the seating surface portion is seated on the valve seat. valve.