JP2023165418A - Motor-operated valve - Google Patents

Motor-operated valve Download PDF

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JP2023165418A
JP2023165418A JP2023127242A JP2023127242A JP2023165418A JP 2023165418 A JP2023165418 A JP 2023165418A JP 2023127242 A JP2023127242 A JP 2023127242A JP 2023127242 A JP2023127242 A JP 2023127242A JP 2023165418 A JP2023165418 A JP 2023165418A
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valve
valve body
lower stopper
stopper
orifice
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将志 矢沢
Masashi Yazawa
竜也 吉田
Tatsuya Yoshida
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Fujikoki Corp
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Fujikoki Corp
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
    • Y02B30/70—Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

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Abstract

To provide a motor-operated valve that can suppress flow rate change due to change in a flow direction of fluid (refrigerant) when a valve element is in a lowermost descent position.SOLUTION: When a valve element 14 is in the lowermost descent position, at least part of a straight part 14s on a side of the valve element 14 overlaps on at least part of a straight part 46s on a side of a valve seat part 46a in an ascent/descent direction.SELECTED DRAWING: Figure 2

Description

本発明は、空気調和機、冷凍機等の冷凍サイクルに流量制御弁等として組み込まれて使用される電動弁に係り、特に、弁体が最下降位置（通常なら全閉状態となる）にあるときでも、弁シート部との間に所定の大きさの間隙が形成される閉弁レスタイプの電動弁に関する。 The present invention relates to a motor-operated valve that is incorporated and used as a flow control valve in a refrigeration cycle of an air conditioner, a refrigerator, etc., and in particular, the present invention relates to a motor-operated valve that is used as a flow control valve etc. in a refrigeration cycle of an air conditioner, a refrigerator, etc. The present invention relates to a non-closing type motor-operated valve in which a gap of a predetermined size is formed between the valve seat and the valve seat even when the valve is closed.

この種の電動弁として、例えば、弁軸と、該弁軸が内挿される円筒部を有するガイドステムと、前記弁軸の下端部に保持固定されて前記ガイドステムに内挿された円筒状の弁ホルダと、該弁ホルダに、前記弁軸に対して軸方向の相対移動及び相対回転可能な状態で内挿され、かつ、前記弁軸との間に縮装されたコイルばねにより下方に付勢されるとともに、前記弁ホルダにより抜け止め係止された弁体と、該弁体が接離する弁シート部を有し、前記ガイドステムが取付固定される弁本体と、該弁本体に接合されたキャンと、該キャンの内周に配在されたロータと、前記弁軸の上端部に外嵌固定された結合部材を介して前記ロータと前記弁軸とを連結するロータホルダと、前記ロータに設けられた係合部が嵌合するべく前記ロータホルダに形成された凹部と、前記ロータを回転駆動すべく前記キャンの外周に配置されたステータと、前記ガイドステムの円筒部内周に配在される雌ねじ部材と、該雌ねじ部材の内周に形成された固定ねじ部と前記弁軸の外周に形成された可動ねじ部とからなる、前記弁体を前記弁シート部に接離させるためのねじ送り機構と、前記ガイドステムの円筒部の外周に配在されて前記ロータの回転上下動規制を行うストッパ機構と、を備え、前記ストッパ機構は、上側係止部及び下側係止部を有する螺旋状の固定ストッパと、前記上側係止部に接当して係止される第１接当部及び前記下側係止部に接当して係止される第２接当部が設けられて、前記固定ストッパの螺旋部分に組み込まれるリング状ないし螺旋状のスライダとからなり、前記スライダは、前記ロータが回転するとき、該ロータに設けられた押動部により前記第１接当部が押動されて、前記第１接当部が前記上側係止部に、また、前記第２接当部が前記下側係止部に接当するまで回転しながら上下動するようにされ、前記スライダの第２接当部が前記下側係止部に接当して停止せしめられた原点位置では、前記弁体と前記弁シート部との間に所定の大きさの間隙が形成されているものが知られている（例えば、特許文献１参照）。 This type of electric valve includes, for example, a guide stem having a valve stem, a cylindrical part into which the valve stem is inserted, and a cylindrical guide stem which is held and fixed to the lower end of the valve stem and inserted into the guide stem. a valve holder; the valve holder is inserted into the valve holder so as to be able to move and rotate relative to the valve shaft in the axial direction, and is attached downwardly by a coil spring compressed between the valve shaft and the valve shaft; The valve body is connected to the valve body, the valve body having a valve body which is pressed against the valve body and is held in place by the valve holder, and a valve seat portion on which the valve body comes into contact with and separates from the body, and a valve body to which the guide stem is attached and fixed. a rotor disposed on the inner periphery of the can; a rotor holder that connects the rotor and the valve shaft via a coupling member externally fitted and fixed to the upper end of the valve shaft; a recess formed in the rotor holder into which an engaging part provided on the rotor holder is fitted; a stator disposed on the outer periphery of the can for rotationally driving the rotor; and a stator disposed on the inner periphery of the cylindrical part of the guide stem. A screw for moving the valve body toward and away from the valve seat, the screw comprising a female threaded member, a fixed threaded portion formed on the inner periphery of the female threaded member, and a movable threaded portion formed on the outer periphery of the valve shaft. a feeding mechanism; and a stopper mechanism disposed on the outer periphery of the cylindrical portion of the guide stem to restrict rotational vertical movement of the rotor, the stopper mechanism having an upper locking portion and a lower locking portion. A helical fixed stopper, a first abutting part that abuts and is locked with the upper latching part, and a second abutting part that abuts and is latched with the lower latching part are provided. and a ring-shaped or spiral-shaped slider incorporated in the spiral portion of the fixed stopper, and the slider is configured such that when the rotor rotates, the first contact portion is pressed by a pushing portion provided on the rotor. The first abutting portion is moved up and down while rotating until the first abutting portion abuts the upper locking portion and the second abutting portion abuts the lower locking portion; At the original position where the second contact portion of the slider comes into contact with the lower locking portion and is stopped, a gap of a predetermined size is formed between the valve body and the valve seat portion. Some are known (for example, see Patent Document 1).

前記した如くの構成を有する電動弁では、弁体が最下降位置（通常なら全閉状態となる）にあるときでも、弁シート部との間に所定の大きさの間隙が形成されるため、通常の閉弁タイプの電動弁と比べて、弁シート部への弁体の喰いつきが確実に防止でき、当該電動弁を空調機に使用する場合、コンプレッサの焼き付きによる運転不具合を防げる利点がある。 In the electric valve having the above-mentioned configuration, even when the valve body is in the lowest position (normally fully closed), a gap of a predetermined size is formed between the valve body and the valve seat. Compared to a normal closing type electric valve, it can reliably prevent the valve body from sticking to the valve seat, and when this electric valve is used in an air conditioner, it has the advantage of preventing operational problems due to compressor seizure. .

特許第５１６４５７９号公報Patent No. 5164579

ところで、前記した如くの従来の閉弁レスタイプの電動弁では、弁本体の弁室の一側部に冷媒入出用の第１導管が、また、弁室の下部に冷媒入出用の第２導管がそれぞれろう付け等により連結固定され、流体（冷媒）が、第１導管から弁室を介して第２導管に向かう一方向（正方向）と、第２導管から弁室を介して第１導管に向かう他方向（逆方向）との双方向に流されるようになっているが、ねじ送り機構（を構成する固定ねじ部と可動ねじ部との間）にはバックラッシ（ねじガタ）が必然的に存在するため、流体（冷媒）の流れ方向が正方向から逆方向、あるいは、逆方向から正方向に変化すると、その流体の圧力によって弁体が付勢され、当該弁体が弁シート部に対して前記バックラッシ（ねじガタ）分だけ上下動してしまう（図７（Ａ）、（Ｂ）参照）。 By the way, in the conventional non-closing type electric valve as described above, there is a first conduit for refrigerant input and output on one side of the valve chamber of the valve body, and a second conduit for refrigerant input and output at the lower part of the valve chamber. are connected and fixed by brazing or the like, and the fluid (refrigerant) flows in one direction (forward direction) from the first conduit through the valve chamber to the second conduit, and from the second conduit through the valve chamber to the first conduit. However, backlash (screw play) is inevitable in the screw feed mechanism (between the fixed screw part and the movable screw part that make up the screw feed mechanism). Therefore, when the flow direction of the fluid (refrigerant) changes from the forward direction to the reverse direction or from the reverse direction to the forward direction, the valve body is urged by the pressure of the fluid, and the valve body is pressed against the valve seat. On the other hand, it moves up and down by the backlash (screw play) (see FIGS. 7(A) and 7(B)).

また、上記従来の電動弁では、通常、弁口オリフィスを流れる流体の通過流量を制御する弁体が逆円錐台面ないしは逆円錐面（テーパ面）で構成されている。そのため、上述のように流体の流れ方向の変化に応じて弁体が弁シート部に対して上下動してしまうと、弁体が原点位置（最下降位置ともいい、モータに対する供給パルス数が０パルスとされる位置）にあるときに、その流体の流れ方向の変化前後で、弁口オリフィスを流れる流体の通過流量（０パルス流量ともいう）が変化してしまうといった課題が生じる（図８参照）。 Further, in the above-mentioned conventional motor-operated valve, the valve body that controls the flow rate of the fluid flowing through the valve orifice usually has an inverted truncated conical surface or an inverted conical surface (tapered surface). Therefore, if the valve body moves up and down relative to the valve seat in response to changes in the fluid flow direction as described above, the valve body will move to the origin position (also called the lowest position), and the number of pulses supplied to the motor will be 0. A problem arises in that the flow rate of fluid flowing through the valve orifice (also referred to as 0 pulse flow rate) changes before and after the flow direction of the fluid changes (see Figure 8). ).

また、上記従来の電動弁では、通常、組立時の弁体の原点位置出しにおいて、弁体のテーパ面を弁シート部に当接させて基準位置を形成し、その基準位置から弁体を弁シート部に対してリフトさせて弁体の原点位置出しを行っている。すなわち、弁体のテーパ面が弁体の原点位置出しの基準面とされている（詳細は、特許文献１等参照）。そのため、原点位置における弁体と弁シート部との間の前記間隙の寸法精度が、弁体のテーパ面の部品精度（加工精度）に依存することとなり、概して前記間隙の寸法ばらつきが大きくなって、流量特性（例えば、中間開度での流量の変曲点）がばらつく可能性がある。 In addition, in the above-mentioned conventional motor-operated valve, when assembling the valve body to locate its original position, the tapered surface of the valve body is brought into contact with the valve seat part to form a reference position, and the valve body is moved from that reference position. The origin position of the valve body is determined by lifting it relative to the seat. That is, the tapered surface of the valve body is used as a reference surface for locating the origin of the valve body (for details, see Patent Document 1, etc.). Therefore, the dimensional accuracy of the gap between the valve body and the valve seat at the origin position depends on the component accuracy (machining accuracy) of the tapered surface of the valve body, and the dimensional variation of the gap generally increases. , the flow rate characteristics (for example, the inflection point of the flow rate at an intermediate opening degree) may vary.

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、弁体が最下降位置にあるときの、流体（冷媒）の流れ方向の変化に伴う流量変化を抑え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 its purpose is to suppress changes in flow rate due to changes in the flow direction of fluid (refrigerant) when the valve body is at the lowest position. Our objective is to provide an electric valve that can

また、本発明の他の目的とするところは、原点位置における弁体と弁シート部との間に形成される間隙の寸法ばらつき、ひいては、流量特性のばらつきを抑えることのできる電動弁を提供することにある。 Another object of the present invention is to provide an electrically operated valve that can suppress variations in the size of the gap formed between the valve body and the valve seat at the origin position, and thus variations in flow characteristics. There is a particular thing.

上記する課題を解決するために、本発明に係る電動弁は、弁軸の先端に設けられた弁体と、前記弁体の下動規制を行うための下部ストッパ機構と、前記弁体が接離又は近接離間する弁シート部を有する弁口オリフィスが設けられた弁本体と、を有し、ロータの回転運動を、雄ネジ部材と雌ネジ部材とのネジ螺合により直線運動に変換し、この直線運動に基づいて前記弁体を前記弁シート部に接離又は近接離間する方向に移動させ、前記下部ストッパ機構により前記弁体が最下降位置にあるときに、所定量の流体が通過するように、前記弁シート部と前記弁体との間に間隙が形成される電動弁であって、前記弁体は、前記弁口オリフィスに挿入したときに前記弁口オリフィスの内周面との間に微小な隙間を形成し、前記弁口オリフィスの軸線と平行な外周面を有する弁体側ストレート部と、前記弁体側ストレート部の先端と連続して形成されたテーパ状の外周面を有するテーパ面部とを備え、前記弁体側ストレート部は、前記弁軸と前記テーパ面部との間に形成され、前記弁体側ストレート部の前記軸線の方向の長さは、前記弁体側ストレート部の直径よりも短く、前記弁体が前記最下降位置にあるとき、前記弁口オリフィスに挿入された前記弁体側ストレート部の軸方向の長さは、前記ネジ螺合時のネジガタ分の軸方向の長さよりも長く形成され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 has a valve body provided at the tip of a valve shaft, a lower stopper mechanism for regulating the downward movement of the valve body, and the valve body is in contact with each other. a valve body provided with a valve orifice having valve seat portions that are spaced apart or close to each other; Based on this linear movement, the valve body is moved toward and away from the valve seat portion, and when the valve body is at the lowest position by the lower stopper mechanism, a predetermined amount of fluid passes through. In the motor-operated valve, a gap is formed between the valve seat portion and the valve body, and the valve body has a gap between the valve body and the inner circumferential surface of the valve orifice when inserted into the valve orifice. a valve body-side straight part that forms a minute gap therebetween and has an outer peripheral surface parallel to the axis of the valve orifice; and a taper that has a tapered outer peripheral surface that is continuous with the tip of the valve body-side straight part. the valve body side straight part is formed between the valve shaft and the tapered surface part, and the length of the valve body side straight part in the direction of the axis is longer than the diameter of the valve body side straight part. Shortly, when the valve body is in the lowest position, the axial length of the valve body side straight part inserted into the valve port orifice is longer than the axial length corresponding to the screw play when the screws are screwed together. It is characterized by its long formation.

好ましい態様では、前記弁口オリフィスは、円筒面からなる弁シート側ストレート部を有する。 In a preferred embodiment, the valve orifice has a valve seat side straight portion having a cylindrical surface.

更に好ましい態様では、前記下部ストッパ機構により前記弁体が最下降位置にあるときに、前記弁体側ストレート部と前記テーパ面部の境界の前記軸線の方向の位置が、前記弁シート側ストレート部の内周面の高さの範囲内に位置する。 In a further preferred embodiment, when the valve body is at the lowest position by the lower stopper mechanism, the position of the boundary between the valve body side straight part and the tapered surface part in the direction of the axis is within the valve seat side straight part. Located within the height of the circumferential surface.

本発明によれば、弁体が最下降位置にあるときに、弁体に設けられた弁体側ストレート部の少なくとも一部と弁シート部に設けられた弁シート側ストレート部の少なくとも一部とが昇降方向で重なるように、各部の寸法形状が設定されている。より詳細には、弁体が最下降位置にあるときにおいて弁体が弁シート部から最も離れるときに（流体が逆方向に流されるときに）、弁体側ストレート部の少なくとも一部と弁シート側ストレート部の少なくとも一部とが昇降方向で重なるようにされている。そのため、弁体が最下降位置にあるときに、流体の流れ方向の変化に応じて弁体が弁シート部に対して上下動しても、弁口オリフィスを流れる流体の通過流量（０パルス流量）が連続的に変化するようになり、例えば弁口オリフィスを流れる流体（冷媒）の通過流量を制御する弁体がテーパ面で構成される従来の電動弁と比べて、弁体が最下降位置にあるときの、流体（冷媒）の流れ方向の変化に伴う流量変化を確実に抑えることができる。 According to the present invention, when the valve body is in the lowest position, at least a portion of the valve body side straight portion provided on the valve body and at least a portion of the valve seat side straight portion provided on the valve seat portion are connected to each other. The dimensions and shapes of each part are set so that they overlap in the vertical direction. More specifically, when the valve body is in the lowest position and is farthest from the valve seat part (when fluid flows in the opposite direction), at least a part of the straight part on the valve body side and the valve seat side At least a portion of the straight portion overlaps with each other in the vertical direction. Therefore, when the valve body is in the lowest position, even if the valve body moves up and down with respect to the valve seat in response to changes in the fluid flow direction, the flow rate (0 pulse flow rate) of the fluid flowing through the valve orifice ) changes continuously, and for example, compared to conventional electric valves where the valve body that controls the flow rate of fluid (refrigerant) flowing through the valve orifice has a tapered surface, the valve body is at its lowest position. It is possible to reliably suppress changes in the flow rate due to changes in the flow direction of the fluid (refrigerant).

また、弁体における弁体側ストレート部の上側に、昇降方向に対して垂直な面を有する弁体側当接部が設けられており、組立時の弁体の原点位置出しにおいて前記弁体が前記最下降位置より下降せしめられたときに、前記弁体の当接部が弁本体に当接せしめられるようにされている。すなわち、弁体における弁体側ストレート部の上側に設けられた当接部（昇降方向に対して垂直な面）が弁体の原点位置出しの基準面とされ、原点位置における弁体と弁シート部との間の間隙の寸法精度が、基本的に弁体の当接部の部品精度（加工精度）に依存することとなる。そのため、例えば弁体のテーパ面が弁体の原点位置出しの基準面とされる従来の電動弁と比べて、前記間隙の寸法ばらつき、ひいては、流量特性（例えば、中間開度での流量の変曲点）のばらつきを効果的に抑えることができる。また、前記した弁体側ストレート部（の昇降方向における長さ）は、当接部（基準面）を基準として決められるので、前記弁体側ストレート部の寸法精度を確保でき、この点からも、流量特性（例えば、中間開度での流量の変曲点）のばらつきをより効果的に抑えることができる。 Further, a valve body side abutting portion having a surface perpendicular to the lifting direction is provided above the valve body side straight portion of the valve body, and the valve body is moved to the uppermost position when locating the origin position of the valve body during assembly. When the valve body is lowered from the lowered position, the contact portion of the valve body is brought into contact with the valve body. In other words, the abutting part (a surface perpendicular to the lifting direction) provided on the upper side of the straight part of the valve body on the valve body side is used as the reference surface for determining the origin position of the valve body, and the valve body and the valve seat part at the origin position are The dimensional accuracy of the gap between the valve body and the valve body basically depends on the component accuracy (processing accuracy) of the abutting portion of the valve body. Therefore, compared to conventional electric valves in which the tapered surface of the valve body is used as the reference surface for locating the origin of the valve body, variations in the dimensions of the gap and, in turn, flow characteristics (for example, changes in flow rate at intermediate opening degrees) It is possible to effectively suppress variations in curve points). In addition, since the above-described straight part on the valve body side (its length in the vertical direction) is determined based on the contact part (reference surface), the dimensional accuracy of the straight part on the valve body side can be ensured, and from this point of view, the flow rate Variations in characteristics (for example, the inflection point of the flow rate at intermediate opening degrees) can be suppressed more effectively.

本発明に係る電動弁の一実施形態を示す縦断面図。FIG. 1 is a vertical cross-sectional view showing an embodiment of an electric valve according to the present 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であり、（Ａ）は正方向流れ状態を示す図、（Ｂ）は逆方向流れ状態を示す図。FIG. 2 is an enlarged longitudinal sectional view of a main part of the electric valve shown in FIG. 1, in which (A) is a diagram showing a forward flow state, and (B) is a diagram showing a reverse flow state. 図１に示される電動弁の流量特性の一例を示す図。2 is a diagram showing an example of flow characteristics of the electric valve shown in FIG. 1. FIG. 図１に示される電動弁の流量特性の他例を示す図。2 is a diagram showing another example of the flow rate characteristics of the electric valve shown in FIG. 1. 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。FIG. 2 is an enlarged longitudinal cross-sectional view of a main part of another example of the electric valve shown in FIG. 1; 図１に示される電動弁の組立工程における、弁体の原点位置（最下降位置）出し工程において、下部ストッパをガイドブッシュに対して回転させる工程の説明に供される上面図及び部分拡大縦断面図。A top view and a partially enlarged vertical cross section used to explain the process of rotating the lower stopper with respect to the guide bush in the process of bringing the valve body to its original position (lowest position) in the assembly process of the electric valve shown in Figure 1. figure. 従来の電動弁の要部を拡大して示す要部拡大縦断面図であり、（Ａ）は正方向流れ状態を示す図、（Ｂ）は逆方向流れ状態を示す図。FIG. 2 is an enlarged vertical cross-sectional view of a main part of a conventional motor-operated valve, in which (A) is a diagram showing a forward flow state, and (B) is a diagram showing a reverse flow state. 従来の電動弁の流量特性を示す図。A diagram showing flow characteristics of a conventional electric valve.

以下、本発明に係る電動弁及びその組立方法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。 DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of an electric valve and a method for assembling the same according to the present invention will be described with reference to the drawings. In each figure, gaps formed between members, separation distances between members, etc. may be exaggerated in order to facilitate understanding of the invention and for convenience in drawing. be. Further, in this specification, descriptions indicating positions and directions such as up and down, right and left are based on the direction arrows shown in FIG. 1, and do not refer to positions and directions in actual use.

また、本明細書では、弁本体における弁室の側方に連結された第１導管から、弁室及び該弁室の底部に形成された縦向きの弁口オリフィスを介して弁室の下方に連結された第２導管に向かう方向を「正方向」とし、第２導管から、弁口オリフィス及び弁室を介して第１導管に向かう方向を「逆方向」としている。 In addition, in this specification, the first conduit connected to the side of the valve chamber in the valve body is connected to the lower part of the valve chamber through the valve chamber and a vertically oriented valve orifice formed at the bottom of the valve chamber. The direction toward the connected second conduit is defined as the "forward direction," and the direction from the second conduit through the valve orifice and the valve chamber toward the first conduit is defined as the "reverse direction."

＜電動弁の構成及び動作＞
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。 <Configuration and operation of electric valve>
FIG. 1 is a longitudinal cross-sectional view showing one embodiment of an electric valve according to the present invention.

図示実施形態の電動弁１は、主に、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（付勢部材）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 mainly includes a stepping motor 50 including a valve stem 10, a guide bush 20, a valve stem holder 30, a valve body 40, a can 55, a rotor 51, and a stator 52. It includes a compression coil spring (biasing member) 60, a retaining member 70, a screw feeding mechanism 28, and a lower stopper mechanism 29.

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、弁口オリフィス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 above. ) is integrally formed with a valve body 14 for controlling the passing flow rate.

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、逆円錐台面からなる上側テーパ面部１４ｔと、上側テーパ面部１４ｔより制御角（弁体１４の中心軸線Ｏと平行な線との交差角）が大きい逆円錐台面からなる下側テーパ面部１４ｕ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 cylindrical surface having a slightly smaller diameter than the lower small diameter portion 13 of the valve shaft 10 (the outer diameter in the vertical direction is A control angle (intersection angle between a straight part (valve body side straight part) 14s consisting of a constant), an upper tapered surface part 14t consisting of an inverted truncated conical surface, and a line parallel to the central axis O of the valve body 14 from the upper tapered surface part 14t. The lower tapered surface portion 14u is formed of a large inverted truncated conical surface.

前記ストレート部１４ｓの昇降方向（上下方向）における長さは、ねじ送り機構２８（を構成する固定ねじ部２３と可動ねじ部３３との間）のバックラッシ（ねじガタ）分以上に設計されている（詳細は後述）。 The length of the straight portion 14s in the vertical direction (vertical direction) is designed to be longer than the backlash (screw play) of the screw feed mechanism 28 (between the fixed screw portion 23 and the movable screw portion 33 that constitute it). (Details below).

また、弁体１４におけるストレート部１４ｓの上側には（当該ストレート部１４ｓに連接して）、弁軸１０の下部小径部１３と弁体１４（のストレート部１４ｓ）との間に形成された段丘面で構成される環状平坦面（水平面）（弁体側当接部）１４ｆが設けられている。この環状平坦面１４ｆは、昇降方向に対して垂直な面とされており、当該電動弁１の組立時の弁体１４の原点位置（最下降位置）出しにおいて当該弁体１４が最下降位置より下降せしめられたときに、弁本体４０（詳細には、弁本体４０の底部壁４５の上面に形成された弁本体側当接部としての環状平坦面４５ｆ）に当接せしめられる基準面とされる（詳細は後述）。 Further, above the straight portion 14s of the valve body 14 (connected to the straight portion 14s), a terrace is formed between the lower small diameter portion 13 of the valve shaft 10 and the valve body 14 (the straight portion 14s of the straight portion 14s). An annular flat surface (horizontal surface) (valve body side contact portion) 14f is provided. This annular flat surface 14f is a surface perpendicular to the ascending and descending direction, and when the valve body 14 is moved to its origin position (lowest position) when assembling the electric valve 1, the valve body 14 is lower than the lowest position. When the valve body 40 is lowered, it serves as a reference surface that comes into contact with the valve body 40 (specifically, an annular flat surface 45f as a valve body side contact portion formed on the upper surface of the bottom wall 45 of the valve body 40). (Details will be explained later).

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の弁シート部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、嵌合部２７の上面２７ａと所定の隙間ｈをあけて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、後で詳述するように、本実施形態では、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 into which the valve shaft 10 (intermediate large diameter portion 12 thereof) is inserted so as to be relatively movable (slidable) in the direction of the axis O and relatively rotatable around the axis O; It extends upward from the upper end of the cylindrical part 21, has a larger inner diameter than the cylindrical part 21, and is inserted into the upper end of the intermediate large diameter part 12 of the valve shaft 10 and the lower end of the upper small diameter part 11. It has a mounting part 22. On the outer periphery of the cylindrical portion 21 of the guide bush 20, there is provided one side of a screw feeding mechanism 28 for raising and lowering the valve body 14 of the valve shaft 10 relative to the valve seat portion 46a of the valve body 40 in accordance with the rotational drive of the rotor 51. A fixing threaded portion (male threaded 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 serves as a fitting portion 27 into the fitting hole 44 of the valve body 40. A lower stopper 25 is screwed and fixed to the fixed screw part 23 (below the valve stem holder 30 in it) with a predetermined gap h from the upper surface 27a of the fitting part 27. A fixed stopper body 24 that constitutes one side of a lower stopper mechanism 29 that restricts the downward rotation of the valve stem holder 30 (that is, the valve stem 10 connected to the valve stem holder 30) is integrally protruded on the outer periphery of the valve stem holder 25. It is set up. In addition, as will be described in detail later, in this embodiment, the upper surface 27a of the fitting part 27 restricts the downward movement of the lower stopper 25 (in other words, the downward movement limit position or the lowest movement position of the lower stopper 25). ) is used as a stopper part.

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 stem holder 30 has a cylindrical part 31 into which the guide bush 20 is inserted, and a ceiling part 32 through which an insertion hole 32a is inserted through which the upper end of the valve stem 10 (the upper small diameter part 11) is inserted. have. A movable threaded part (female threaded part) 33 is formed on the inner periphery of the cylindrical part 31 of the valve stem holder 30, and is screwed into the fixed threaded part 23 of the guide bush 20 to constitute the screw feeding mechanism 28. A movable stopper body 34, which constitutes the other part of the lower stopper mechanism 29, is integrally protruded 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（付勢部材）６０が縮装されている。 Further, between the terrace surface formed between the upper small diameter portion 11 and the intermediate large diameter portion 12 of the valve stem 10 and the lower surface of the ceiling portion 32 of the valve stem holder 30, there is a gap between the upper small diameter portion of the valve stem 10 The valve shaft 10 and the valve shaft holder 30 are biased in a direction that separates them in the vertical direction (axis O direction) so that the valve shaft 10 and the valve shaft holder 30 are inserted into the section 11. In other words, the valve shaft 10 (valve body 14) is always pushed downward. A compression coil spring (biasing member) 60 that biases 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４５に、前記弁体１４が接離又は近接離間する弁シート部４６ａを有する略円錐台状の弁口オリフィス４６が形成されるとともに、その弁シート部４６ａには、円筒面（昇降方向で内径が一定）からなるストレート部（弁シート側ストレート部）４６ｓが設けられている（図２参照）。 The valve body 40 is made of a cylindrical body made of metal such as brass or SUS. This valve body 40 has a valve chamber 40a into which fluid is introduced and extracted, and a first conduit 41a is connected and fixed by brazing or the like to a horizontal first opening 41 provided on the side of the valve chamber 40a. and an insertion hole through which the valve shaft 10 (intermediate large diameter portion 12 thereof) is inserted in the ceiling of the valve chamber 40a so as to be relatively movable (slidable) in the direction of the axis O and relatively rotatable around the axis O. 43 and a fitting hole 44 into which the lower part (fitting part 27) of the guide bush 20 is fitted and fixed. The two conduits 42a are connected and fixed by brazing or the like. Further, a substantially truncated conical valve orifice 46 is provided on a bottom wall 45 provided between the valve chamber 40a and the second opening 42, and has a valve seat portion 46a on which the valve body 14 moves toward and away from, or toward and away from, the bottom wall 45. The valve seat portion 46a is provided with a straight portion (valve seat side straight portion) 46s having a cylindrical surface (inner diameter is constant in the vertical direction) (see FIG. 2).

前記ストレート部４６ｓ（の内径）は、前記弁体１４のストレート部１４ｓより若干大径、かつ、前記弁軸１０の下部小径部１３より小径に設計されている。 The straight portion 46s (inner diameter thereof) is designed to have a slightly larger diameter than the straight portion 14s of the valve body 14 and a smaller diameter than the lower small diameter portion 13 of the valve shaft 10.

また、弁本体４０の底部壁４５の上面における弁口オリフィス４６（弁シート部４６ａ）周りは、環状平坦面（水平面）（弁本体側当接部）４５ｆとされており、当該環状平坦面４５ｆが、当該電動弁１の組立時の弁体１４の原点位置（最下降位置）出しにおいて弁体１４側の環状平坦面１４ｆと平面で当接せしめられる当接面（基準面）とされる（詳細は後述）。 Further, the area around the valve orifice 46 (valve seat portion 46a) on the upper surface of the bottom wall 45 of the valve body 40 is an annular flat surface (horizontal surface) (valve body side contact portion) 45f. is a contact surface (reference surface) that is brought into plane contact with the annular flat surface 14f on the valve body 14 side when the valve body 14 is moved to its original position (lowest position) during assembly of the electric valve 1 ( (Details below).

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, a flange-shaped plate 47 is fixed to the upper end of the valve body 40 by caulking or the like, and a lower end of a cylindrical can 55 with a ceiling is attached to a stepped portion provided on the outer periphery of the flange-shaped plate 47. Sealed joint 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 disposed inside the can 55 and outside the guide bush 20 and the valve stem holder 30, and a yoke 52a is provided outside the can 55 to rotate the rotor 51. A stator 52 consisting of a bobbin 52b, a stator coil 52c, a resin mold cover 52d, etc. 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 a substrate 52f, and are arranged in the can 55 by energizing the stator coil 52c. The rotor 51 located therein rotates around an 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 disposed within the can 55 is engaged with and supported by the valve stem holder 30, and the valve stem holder 30 rotates together with the rotor 51 (integrally).

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。 In detail, the rotor 51 has a double pipe configuration consisting of an inner cylinder 51a, an outer cylinder 51b, and a connecting part 51c that connects the inner cylinder 51a and the outer cylinder 51b at a predetermined angular position around the axis O, Vertical grooves 51d extending in the direction of the axis O (vertical direction) are formed on the inner periphery of the inner cylinder 51a (for example, at angular intervals 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, protrusions 30a extending vertically (for example, at angular intervals of 120 degrees around the axis O) are provided on the outer periphery (upper half portion) of the valve stem holder 30, and the lower part of the protrusions 30a Upward locking surfaces (not shown) that support the rotor 51 are formed on both sides.

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 protrusion 30a of the valve stem holder 30 are engaged, and the lower surface of the inner cylinder 51a of the rotor 51 and the locking surface of the valve stem holder 30 are in contact with each other. The rotor 51 is supported and fixed in a state aligned with the valve stem holder 30, and the valve stem holder 30 rotates together with the rotor 51 while supporting the rotor 51 within 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。 Above the rotor 51 and the valve stem holder 30, there is a valve that prevents relative movement between the valve stem holder 30 and the rotor 51 in the vertical direction (in other words, presses the rotor 51 downward against the valve stem holder 30). In order to connect the shaft 10 and the valve shaft holder 30, a push nut 71 is externally fitted and fixed to the upper end of (the upper small diameter portion 11 of) the valve shaft 10 by press fitting, welding, etc., and the push nut 71 and the rotor 51. A retaining member 70 is interposed between the rotor retainer 72 and a rotor retainer 72 made of a disc-shaped member having an insertion hole 72a formed in the center through which the upper end of the valve shaft 10 is inserted. ing. That is, the rotor 51 is held between the valve stem holder 30, which is urged upward by the urging force of the compression coil spring 60, and the rotor presser 72. Note that the height (in the vertical direction) from the upper end of the valve stem holder 30 to the locking surface is the same as the height (in the vertical direction) of the inner cylinder 51a of the rotor 51, and the height (in the vertical direction) of the valve stem holder 30 (the ceiling part 32 of) ) is in contact with the lower surface (flat surface) of the rotor presser 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。 In addition, the push nut 71 fixed to the upper end of the valve stem 10 may cause the valve stem holder 30 to move too upwardly relative to the guide bush 20 during operation, causing the fixing screw portion 23 of the guide bush 20 to In order to prevent the shaft holder 30 from being unscrewed from the movable threaded portion 33, a return spring 75 made of a coil spring that biases the valve shaft holder 30 toward the guide bush 20 is provided on the outside.

そして、当該電動弁１では、例えば弁シート部４６ａへの弁体１４の喰いつきを防止すると共に、低流量域での制御性を確保すべく、弁体１４が最下降位置（原点位置）にあるときに、弁体１４と弁シート部４６ａとの間に所定の大きさの間隙が形成されるようになっている。本例では、弁体１４のストレート部１４ｓと弁本体４０の底部壁４５のストレート部４６ｓとの間、及び、ストレート部１４ｓに連接する環状平坦面１４ｆとストレート部４６ｓに連接する環状平坦面４５ｆとの間に、所定の大きさの間隙が形成されるようになっている。 In the electric valve 1, the valve element 14 is moved to the lowest position (origin position) in order to prevent the valve element 14 from sticking to the valve seat portion 46a, for example, and to ensure controllability in the low flow rate range. At some point, a gap of a predetermined size is formed between the valve body 14 and the valve seat portion 46a. In this example, between the straight part 14s of the valve body 14 and the straight part 46s of the bottom wall 45 of the valve body 40, and between the annular flat surface 14f connected to the straight part 14s and the annular flat surface 45f connected to the straight part 46s. A gap of a predetermined size is formed between the two.

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と弁シート部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。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でも、弁体１４と弁シート部４６ａとの間に間隙（閉弁時要求リフト量）が形成されるため、所定量の通過流量が確保される（図３参照）。 In the electric valve 1 having such a configuration, when the rotor 51 is rotated by energizing the stator 52 (the stator coil 52c thereof), the valve stem holder 30 and the valve stem 10 are rotated together with the rotor 51. At this time, the valve stem 10 is raised and lowered together with the valve body 14 by the screw feeding mechanism 28 consisting of the fixed screw portion 23 of the guide bush 20 and the movable screw portion 33 of the valve stem holder 30. The gap (lift amount, valve opening degree) between the valve seat portion 46a and the valve seat portion 46a is increased or decreased to adjust the flow rate of fluid such as refrigerant. Further, the movable stopper body 34 of the valve stem 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 even when the valve body 14 is in the lowest position, the valve body 14 and the valve seat Since a gap (required lift amount when closing the valve) is formed between the valve and the portion 46a, a predetermined amount of flow rate is ensured (see FIG. 3).

ところで、本実施形態の電動弁１では、流体（冷媒）が、双方向、具体的には、第１導管４１ａ（第１開口４１）から弁室４０ａ及び弁口オリフィス４６を介して第２導管４２ａ（第２開口４２）に向かう方向（つまり、横→下方向）（以下、この状態を正方向流れ状態という）と、第２導管４２ａ（第２開口４２）から弁口オリフィス４６及び弁室４０ａを介して第１導管４１ａ（第１開口４１）に向かう方向（つまり、下→横方向）（以下、この状態を逆方向流れ状態という）との双方向に流されるようになっており、その流体の圧力によって、前記正方向流れ状態では、弁体１４が下方に付勢され、前記逆方向流れ状態では、弁体１４が上方に付勢される。そして、弁体１４を弁シート部４６ａに対して昇降させるねじ送り機構２８では、弁体１４（弁軸１０）が連結される弁軸ホルダ３０の可動ねじ部３３と、弁本体４０に連結固定されるガイドブッシュ２０の固定ねじ部２３との間に、バックラッシ（ねじガタ）が存在する。そのため、前記正方向流れ状態では、弁体１４が（弁軸ホルダ３０の可動ねじ部３３の下面側とガイドブッシュ２０の固定ねじ部２３の上面側とが接触するまで）下方に移動せしめられ（図２（Ａ）に示される状態）、前記逆方向流れ状態では、弁体１４が（弁軸ホルダ３０の可動ねじ部３３の上面側とガイドブッシュ２０の固定ねじ部２３の下面側とが接触するまで）上方に移動せしめられる（図２（Ｂ）に示される状態）。すなわち、流体（冷媒）の流れ方向が正方向から逆方向、あるいは、逆方向から正方向に変化すると、弁体１４が弁シート部４６ａに対して前記バックラッシ分だけ上下動する。 By the way, in the electric valve 1 of this embodiment, the fluid (refrigerant) flows in both directions, specifically, from the first conduit 41a (first opening 41) to the second conduit via the valve chamber 40a and the valve orifice 46. 42a (second opening 42) (that is, from the side to the bottom) (hereinafter, this state is referred to as a forward flow state), and from the second conduit 42a (second opening 42) to the valve orifice 46 and the valve chamber. 40a toward the first conduit 41a (first opening 41) (that is, downward to lateral direction) (hereinafter, this state is referred to as a reverse flow state). The pressure of the fluid forces the valve body 14 downward in the forward flow state, and forces the valve body 14 upward in the reverse flow state. In the screw feeding mechanism 28 that raises and lowers the valve body 14 relative to the valve seat portion 46a, the valve body 14 (valve stem 10) is connected and fixed to the movable screw portion 33 of the valve stem holder 30 and the valve body 40. There is backlash (screw play) between the guide bush 20 and the fixing screw portion 23. Therefore, in the forward flow state, the valve body 14 is moved downward (until the lower surface side of the movable screw portion 33 of the valve stem holder 30 and the upper surface side of the fixed screw portion 23 of the guide bush 20 come into contact). 2(A)), in the reverse flow state, the valve body 14 (the upper surface side of the movable screw portion 33 of the valve shaft holder 30 and the lower surface side of the fixed screw portion 23 of the guide bushing 20 are in contact with each other). (the state shown in FIG. 2(B)). That is, when the flow direction of the fluid (refrigerant) changes from the forward direction to the reverse direction or from the reverse direction to the forward direction, the valve body 14 moves up and down relative to the valve seat portion 46a by the amount of the backlash.

ここで、本実施形態では、弁体１４が最下降位置にあるときに、弁体１４側のストレート部１４ｓの少なくとも一部と弁シート部４６ａ側のストレート部４６ｓの少なくとも一部とが昇降方向（上下方向）で重なる（ラップする）ように、各部の寸法形状が設定されている。より詳細には、ストレート部１４ｓの昇降方向（上下方向）における長さが、ねじ送り機構２８（を構成する固定ねじ部２３と可動ねじ部３３との間）のバックラッシ分以上に設計され、弁体１４が最下降位置にあるときにおいて弁体１４が弁シート部４６ａから最も離されるときに（逆方向流れ状態）、弁体１４側のストレート部１４ｓの下側部分と弁シート４６ａ側のストレート部４６ｓの上側部分とが、昇降方向で重なり量（ラップ量）Ｌｍｉｎだけ重なるようにされている（図２（Ｂ）に示される状態）。 Here, in the present embodiment, when the valve body 14 is at the lowest position, at least a portion of the straight portion 14s on the valve body 14 side and at least a portion of the straight portion 46s on the valve seat portion 46a side move in the vertical direction. The dimensions and shapes of each part are set so that they overlap (wrap) in the vertical direction. More specifically, the length of the straight portion 14s in the vertical direction (vertical direction) is designed to be longer than the backlash of the screw feed mechanism 28 (between the fixed screw portion 23 and the movable screw portion 33 that constitute the same), When the valve body 14 is in the lowest position and the valve body 14 is farthest away from the valve seat 46a (reverse flow state), the lower part of the straight part 14s on the valve body 14 side and the straight part on the valve seat 46a side The upper portion of the portion 46s overlaps by an amount of overlap (wrap amount) Lmin in the vertical direction (the state shown in FIG. 2(B)).

また、この場合、正方向流れ状態では、弁体１４側のストレート部１４ｓと弁シート部４６ａ側のストレート部４６ｓとの昇降方向での重なり量Ｌｍａｘは、前記重なり量Ｌｍｉｎにねじ送り機構２８のバックラッシ分を足した量となっている（図２（Ａ）に示される状態）。 In this case, in the forward flow state, the overlapping amount Lmax of the straight portion 14s on the valve body 14 side and the straight portion 46s on the valve seat portion 46a side in the vertical direction is equal to the overlapping amount Lmin of the screw feeding mechanism 28. The amount is the sum of the backlash (the state shown in FIG. 2(A)).

そのため、図３に示される如くに、弁体１４が最下降位置にあるときに、正方向から逆方向、あるいは、逆方向から正方向に流体の流れ方向が変化して弁体１４が弁シート部４６ａに対して上下動しても、弁口オリフィス４６を流れる流体の通過流量（０パルス流量）が連続的に変化するようになり、例えば弁口オリフィスを流れる流体（冷媒）の通過流量を制御する弁体がテーパ面で構成される従来の電動弁と比べて、弁体１４が最下降位置にあるときの、流体（冷媒）の流れ方向の変化に伴う流量変化を確実に抑えることができる。 Therefore, as shown in FIG. 3, when the valve body 14 is at the lowest position, the fluid flow direction changes from the normal direction to the reverse direction, or from the reverse direction to the positive direction, and the valve body 14 moves toward the valve seat. Even when the portion 46a moves up and down, the flow rate (0 pulse flow rate) of the fluid flowing through the valve orifice 46 changes continuously.For example, the flow rate of the fluid (refrigerant) flowing through the valve orifice 46 changes continuously. Compared to conventional electric valves in which the valve body to be controlled has a tapered surface, it is possible to reliably suppress changes in flow rate due to changes in the flow direction of the fluid (refrigerant) when the valve body 14 is at the lowest position. can.

また、本実施形態では、弁体１４におけるストレート部１４ｓの上側に、昇降方向に対して垂直な面を有する環状平坦面（弁体側当接部）１４ｆが設けられると共に、弁本体４０の底部壁４５の上面における弁口オリフィス４６（弁シート部４６ａ）周りに環状平坦面（弁本体側当接部）４５ｆが設けられており、組立時の弁体１４の原点位置（最下降位置）出しにおいて前記弁体１４が前記最下降位置より下降せしめられたときに、弁体１４側の環状平坦面１４ｆが弁本体４０側の環状平坦面４５ｆに当接せしめられるようにされている。すなわち、弁体１４におけるストレート部１４ｓの上側に設けられた環状平坦面１４ｆ及び弁本体４０の環状平坦面４５ｆが弁体１４の原点位置出しの基準面とされ、原点位置における弁体１４と弁シート部４６ａとの間の間隙の寸法精度が、基本的に弁体１４の環状平坦面１４ｆの部品精度（加工精度）に依存することとなる（後で詳述）。そのため、例えば弁体のテーパ面が弁体の原点位置出しの基準面とされる従来の電動弁と比べて、前記間隙の寸法ばらつき、ひいては、流量特性（例えば、中間開度での流量の変曲点）のばらつきを効果的に抑えることができる。また、前記した弁体１４側のストレート部１４ｓの昇降方向における長さは、環状平坦面１４ｆ（基準面）を基準として決められるので、前記弁体１４側のストレート部１４ｓの寸法精度を確保でき、この点からも、流量特性（例えば、中間開度での流量の変曲点）のばらつきをより効果的に抑えることができる。 Further, in this embodiment, an annular flat surface (valve body side contact portion) 14f having a surface perpendicular to the lifting direction is provided above the straight portion 14s of the valve body 14, and the bottom wall of the valve body 40 An annular flat surface (valve body side contact portion) 45f is provided around the valve orifice 46 (valve seat portion 46a) on the upper surface of the valve body 45, and when the valve body 14 is brought out to its original position (lowest position) during assembly, When the valve body 14 is lowered from the lowest position, the annular flat surface 14f on the valve body 14 side is brought into contact with the annular flat surface 45f on the valve body 40 side. That is, the annular flat surface 14f provided above the straight portion 14s of the valve body 14 and the annular flat surface 45f of the valve body 40 are used as reference surfaces for determining the origin position of the valve body 14, and the valve body 14 and the valve at the origin position are The dimensional accuracy of the gap with the seat portion 46a basically depends on the component accuracy (processing accuracy) of the annular flat surface 14f of the valve body 14 (described in detail later). Therefore, compared to conventional electric valves in which the tapered surface of the valve body is used as the reference surface for locating the origin of the valve body, variations in the dimensions of the gap and, in turn, flow characteristics (for example, changes in flow rate at intermediate opening degrees) It is possible to effectively suppress variations in curve points). Further, since the length of the straight portion 14s on the valve body 14 side in the vertical direction is determined based on the annular flat surface 14f (reference surface), the dimensional accuracy of the straight portion 14s on the valve body 14 side can be ensured. Also from this point of view, variations in the flow rate characteristics (for example, the inflection point of the flow rate at an intermediate opening degree) can be more effectively suppressed.

なお、図３に示される例では、弁体１４が上方に付勢される逆方向流れ状態において、弁体１４側のストレート部１４ｓの下側部分と弁シート部４６ａ側のストレート部４６ｓの上側部分とが昇降方向で所定の重なり量Ｌｍｉｎだけ重なるようにされているが、例えば、図４に示される如くに、前記逆方向流れ状態において、弁体１４側のストレート部１４ｓの下端部と弁シート部４６ａ側のストレート部４６ｓの上端部とが一致する（つまり、昇降方向での重なり量Ｌｍｉｎを０とする）ように、各部の寸法形状を設定してもよい。この場合、正方向流れ状態では、弁体１４側のストレート部１４ｓと弁シート部４６ａ側のストレート部４６ｓとの昇降方向での重なり量Ｌｍａｘは、ねじ送り機構２８のバックラッシ分となる。 In the example shown in FIG. 3, in a reverse flow state where the valve body 14 is urged upward, the lower part of the straight part 14s on the valve body 14 side and the upper part of the straight part 46s on the valve seat part 46a side For example, as shown in FIG. 4, in the reverse flow state, the lower end of the straight part 14s on the valve body 14 side and the valve The dimensions and shapes of each part may be set so that the upper end of the straight part 46s on the side of the seat part 46a coincides (that is, the overlapping amount Lmin in the vertical direction is set to 0). In this case, in the forward flow state, the overlapping amount Lmax of the straight portion 14s on the valve body 14 side and the straight portion 46s on the valve seat portion 46a side in the vertical direction corresponds to the backlash of the screw feeding mechanism 28.

また、上記実施形態では、弁体１４側の環状平坦面１４ｆと弁本体４０側の環状平坦面４５ｆとが面で当接する構成としたが、面以外で当接する構成でもよく、例えば、弁体１４側の環状平坦面１４ｆ及び弁本体４０側の環状平坦面４５ｆの一方又は双方を断面突起状としてもよい。 Further, in the above embodiment, the annular flat surface 14f on the valve body 14 side and the annular flat surface 45f on the valve body 40 side are in contact with each other in a plane, but they may be in contact with each other in a plane other than the plane, for example, One or both of the annular flat surface 14f on the 14 side and the annular flat surface 45f on the valve body 40 side may have a protruding cross section.

また、上記実施形態では、弁本体４０の底部壁４５に、ストレート部４６ｓが設けられた弁シート部４６ａを有する弁口オリフィス４６が形成されているが、例えば、図５に示される如くに、ストレート部４６ｓが設けられた弁シート部４６ａを有する弁口オリフィス４６が形成されたシート部材４８を切削加工等により作製し、そのシート部材４８を弁本体４０の底部壁４５に設けられた嵌挿穴４９に内挿固定してもよい。この場合、シート部材４８の上面における弁口オリフィス４６（弁シート部４６ａ）周りが、環状平坦面（水平面）（弁本体側当接部）４８ｆとされ、当該電動弁１の組立時の弁体１４の原点位置（最下降位置）出しにおいて弁体１４側の環状平坦面１４ｆと平面で当接せしめられる当接面（基準面）とされる。 Further, in the above embodiment, the valve orifice 46 having the valve seat portion 46a provided with the straight portion 46s is formed on the bottom wall 45 of the valve body 40, but for example, as shown in FIG. A seat member 48 in which a valve orifice 46 is formed and has a valve seat portion 46a provided with a straight portion 46s is produced by cutting or the like, and the seat member 48 is inserted into a fitting provided on the bottom wall 45 of the valve body 40. It may be inserted and fixed into the hole 49. In this case, the area around the valve orifice 46 (valve seat portion 46a) on the upper surface of the seat member 48 is an annular flat surface (horizontal surface) (valve body side contact portion) 48f, and the valve body when the electric valve 1 is assembled is This is a contact surface (reference surface) that is brought into plane contact with the annular flat surface 14f on the valve body 14 side when the valve body 14 is moved to its original position (lowest position).

図５に示される如くに、弁本体４０とは別部品のシート部材４８を使用することにより、シート部材４８の部品精度、特に、ストレート部４６ｓや環状平坦面４８ｆの寸法精度等を高められるので、流量特性のばらつきを更に効果的に抑えることができる。 As shown in FIG. 5, by using the seat member 48 which is a separate part from the valve body 40, the precision of the seat member 48, especially the dimensional precision of the straight portion 46s and the annular flat surface 48f, can be improved. , variations in flow characteristics can be suppressed more effectively.

＜電動弁の組立方法＞
前述の電動弁１の組立工程の一例、特に、弁体１４の原点位置（最下降位置）出し工程の一例を、図１及び図２を参照しながら概説すると、まず、弁軸１０、ガイドブッシュ２０、下部ストッパ２５、圧縮コイルばね６０、弁軸ホルダ３０、ロータ５１、弁本体４０等を組み付ける。このとき、下部ストッパ２５は、ガイドブッシュ２０に対して相対回転可能に螺合させておく。なお、下部ストッパ２５は、この段階で、ガイドブッシュ２０のストッパ部２７ａと当接させて配置してもよいし、そのストッパ部２７ａと間隔をあけて配置してもよい。次いで、弁軸１０の下端部に設けられた弁体１４が弁シート部４６ａに当接し（すなわち、弁体１４の環状平坦面１４ｆが弁本体４０の環状平坦面４５ｆに当接し）、圧縮コイルばね６０が若干圧縮され、弁軸ホルダ３０の可動ストッパ体３４と下部ストッパ２５の固定ストッパ体２４とが当接し、かつ、下部ストッパ２５（の下面）がガイドブッシュ２０のストッパ部２７ａと当接するまで、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を利用して、前記弁軸ホルダ３０、ロータ５１、及び弁軸１０を回転させながら下降させる。そして、このように弁軸ホルダ３０が最下動位置に位置せしめられ、かつ、弁体１４が最下降位置より下降せしめられてその環状平坦面１４ｆが弁本体４０の環状平坦面４５ｆに当接された状態で、弁軸１０の上端部に、ロータ押さえ７２を嵌め込むと共にプッシュナット７１を圧入・溶接等により外嵌固定する。 <How to assemble the electric valve>
An example of the assembly process of the above-mentioned electric valve 1, in particular, an example of the process of bringing the valve body 14 to its original position (lowest position) will be summarized with reference to FIGS. 1 and 2. First, the valve stem 10, the guide bush 20, assemble the lower stopper 25, compression coil spring 60, valve shaft holder 30, rotor 51, valve body 40, etc. At this time, the lower stopper 25 is screwed into the guide bush 20 so as to be relatively rotatable. Note that, at this stage, the lower stopper 25 may be placed in contact with the stopper portion 27a of the guide bush 20, or may be placed at a distance from the stopper portion 27a. Next, the valve body 14 provided at the lower end of the valve shaft 10 comes into contact with the valve seat portion 46a (that is, the annular flat surface 14f of the valve body 14 comes into contact with the annular flat surface 45f of the valve body 40), and the compression coil The spring 60 is slightly compressed, the movable stopper body 34 of the valve stem holder 30 and the fixed stopper body 24 of the lower stopper 25 come into contact, and the lower stopper 25 (lower surface) comes into contact with the stopper part 27a of the guide bush 20. Until then, the valve stem holder 30, rotor 51, and valve stem 10 are lowered while rotating by using the screw feeding mechanism 28 consisting of the fixed screw part 23 of the guide bush 20 and the movable screw part 33 of the valve stem holder 30. let In this way, the valve stem holder 30 is positioned at the lowest movable position, and the valve body 14 is lowered from the lowest position so that its annular flat surface 14f comes into contact with the annular flat surface 45f of the valve body 40. In this state, the rotor retainer 72 is fitted onto the upper end of the valve stem 10, and the push nut 71 is externally fitted and fixed by press-fitting, welding, or the like.

次に、上記状態から、弁軸１０、弁軸ホルダ３０、ロータ５１、抜け止め係止部材７０（プッシュナット７１とロータ押さえ７２）等が一体とされた組立体を、前記ねじ送り機構２８を利用して回転させながら上昇させてガイドブッシュ２０から取り外した後、下部ストッパ２５をガイドブッシュ２０に対して開弁方向（図示例では、平面視で反時計回り）に所定回転角度だけ回転させる。そして、その下部ストッパ２５を、ガイドブッシュ２０（の固定ねじ部２３）に溶接・溶着・接着等により相対回転不能に連結固定した後、再びねじ送り機構２８を利用して前記組立体をガイドブッシュ２０に組み付ける。これにより、下部ストッパ２５の固定ストッパ体２４のガイドブッシュ２０に対する位置が変わるので、弁軸ホルダ３０の可動ストッパ体３４と下部ストッパ２５の固定ストッパ体２４とが当接して、弁軸ホルダ３０が最下動位置にあるとき（つまり、弁体１４が最下降位置にあるとき）でも、弁体１４と弁シート部４６ａとの間に所定の大きさの間隙（正方向流れ状態での昇降方向における寸法がＨの間隙）が形成される（図２（Ａ）参照）。このとき、弁体１４側のストレート部１４ｓと弁シート部４６ａ側のストレート部４６ｓとの昇降方向での重なり量Ｌｍａｘは、例えば、ねじ送り機構２８のバックラッシ分とされる。なお、前記組立体を上昇させてガイドブッシュ２０から取り外した後、下部ストッパ２５をガイドブッシュ２０に対して開弁方向に所定回転角度だけ回転させ、その下部ストッパ２５をガイドブッシュ２０に溶接・溶着・接着等により相対回転不能に連結固定するものとして説明したが、前記組立体をガイドブッシュ２０に対して上昇させるだけで、下部ストッパ２５をガイドブッシュ２０に対して開弁方向に所定回転角度だけ回転させることができ、かつ下部ストッパ２５をガイドブッシュ２０に溶接・溶着・接着等により相対回転不能に連結固定することができる程度の隙間を形成することができれば、前記組立体をガイドブッシュ２０から取り外す必要はない。 Next, from the above state, the assembly including the valve stem 10, the valve stem holder 30, the rotor 51, the retaining member 70 (push nut 71 and the rotor retainer 72), etc. After removing the lower stopper 25 from the guide bush 20 by raising it while rotating, the lower stopper 25 is rotated by a predetermined rotation angle in the valve opening direction (in the illustrated example, counterclockwise in plan view) with respect to the guide bush 20. After the lower stopper 25 is connected and fixed to the guide bush 20 (the fixing screw portion 23 thereof) by welding, welding, adhesion, etc. so as not to be relatively rotatable, the screw feeding mechanism 28 is used again to move the assembly to the guide bush 20. Assemble to 20. As a result, the position of the fixed stopper body 24 of the lower stopper 25 with respect to the guide bush 20 changes, so the movable stopper body 34 of the valve stem holder 30 and the fixed stopper body 24 of the lower stopper 25 come into contact, and the valve stem holder 30 Even when the valve body 14 is at the lowest moving position (that is, when the valve body 14 is at the lowest position), a gap of a predetermined size is maintained between the valve body 14 and the valve seat portion 46a (in the vertical direction in the forward flow state). A gap with a dimension of H is formed (see FIG. 2(A)). At this time, the overlapping amount Lmax between the straight portion 14s on the side of the valve body 14 and the straight portion 46s on the side of the valve seat portion 46a in the up-and-down direction is, for example, the amount of backlash of the screw feeding mechanism 28. After the assembly is raised and removed from the guide bush 20, the lower stopper 25 is rotated by a predetermined rotation angle in the valve opening direction with respect to the guide bush 20, and the lower stopper 25 is welded to the guide bush 20.・Although the description has been made assuming that the assembly is connected and fixed non-rotatably by adhesive or the like, by simply lifting the assembly relative to the guide bush 20, the lower stopper 25 can be rotated by a predetermined angle in the valve opening direction relative to the guide bush 20. If the lower stopper 25 can be rotated and a gap large enough to connect and fix the lower stopper 25 to the guide bush 20 by welding, welding, adhesion, etc. so that it cannot rotate relative to the guide bush 20, the assembly can be removed from the guide bush 20. There is no need to remove it.

なお、下部ストッパ２５の雌ねじ部２６やガイドブッシュ２０の固定ねじ部（雄ねじ部）２３にバックラッシレス（ノンバックラッシ）タイプのねじ部を採用する場合には、弁体１４と弁シート部４６ａとの間に形成される間隙の昇降方向における寸法Ｈは、下部ストッパ２５（の下面）とガイドブッシュ２０のストッパ部２７ａとの隙間ｈと一致もしくは略一致する。しかし、一般に、ねじ部にはバックラッシ（遊び又はガタ）が設けられている。そのため、上記実施形態のように下部ストッパ２５をガイドブッシュ２０のストッパ部２７ａと当接させて締め込んだ後に開弁方向に回転させて（緩めて）弁体１４の原点位置出しを行う場合、前記下部ストッパ２５は、回転当初の段階では、ガイドブッシュ２０のストッパ部２７ａに当接したまま（すなわち、上昇せずに）回転するため、前記寸法Ｈは前記隙間ｈと必ずしも一致しない。 Note that when backlash-less (non-backlash) type threaded parts are adopted for the female threaded part 26 of the lower stopper 25 and the fixed threaded part (male threaded part) 23 of the guide bush 20, the connection between the valve body 14 and the valve seat part 46a is A dimension H of the gap formed therebetween in the vertical direction matches or substantially matches the gap h between the lower stopper 25 (the lower surface thereof) and the stopper portion 27a of the guide bush 20. However, generally, a threaded portion is provided with backlash (play or play). Therefore, when the lower stopper 25 is brought into contact with the stopper portion 27a of the guide bush 20 and tightened, and then rotated (loosened) in the valve opening direction to locate the origin of the valve body 14, as in the above embodiment, At the initial stage of rotation, the lower stopper 25 rotates while contacting the stopper portion 27a of the guide bush 20 (that is, without rising), so the dimension H does not necessarily match the gap h.

具体的には、図６を参照すればよく理解されるように、下部ストッパ２５の雌ねじ部２６とガイドブッシュ２０の固定ねじ部２３との間のバックラッシ分の回転角度をθｂ[°]（図示例では、約１８０°）とした場合、上記した原点位置出し工程において、下部ストッパ２５をガイドブッシュ２０のストッパ部２７ａと当接させて締め込んだ状態（この状態では、下部ストッパ２５の雌ねじ部２６の上面側とガイドブッシュ２０の固定ねじ部２３の下面側とが接触）から、当該下部ストッパ２５を開弁方向に回転させる（緩める）と、バックラッシ分の回転角度θｂ[°]の範囲内では、自重により下部ストッパ２５（の下面）はガイドブッシュ２０のストッパ部２７ａと当接し続ける（図６の（１）～（３））。ただし、下部ストッパ２５自体は回転するため、当該下部ストッパ２５に設けられた固定ストッパ体２４の回転位置は変化する。 Specifically, as can be well understood with reference to FIG. In the illustrated example, when the angle is approximately 180°), in the above-described origin positioning step, the lower stopper 25 is brought into contact with the stopper portion 27a of the guide bush 20 and tightened (in this state, the female threaded portion of the lower stopper 25 is tightened). When the lower stopper 25 is rotated (loosened) in the valve opening direction from the point where the upper surface side of the guide bush 26 contacts the lower surface side of the fixing screw portion 23 of the guide bush 20, the rotation angle θb [°] corresponding to the backlash is within the range of the rotation angle θb [°]. Then, the lower stopper 25 (lower surface) continues to contact the stopper portion 27a of the guide bush 20 due to its own weight ((1) to (3) in FIG. 6). However, since the lower stopper 25 itself rotates, the rotational position of the fixed stopper body 24 provided on the lower stopper 25 changes.

仮に、このバックラッシ分の回転角度θｂ[°]の範囲内で下部ストッパ２５をガイドブッシュ２０に固定し、ねじ送り機構２８を利用して弁軸ホルダ３０を回転させながら下降させ、弁軸ホルダ３０の可動ストッパ体３４と下部ストッパ２５の固定ストッパ体２４とを当接させると、弁軸ホルダ３０の最下動位置は、下部ストッパ２５の回転量に応じて次第に上昇することとなる。例えば、バックラッシ相殺時点での弁軸ホルダ３０の最下降位置の上昇量Ｈｂは、下部ストッパ２５の雌ねじ部２６のねじピッチ（ねじ山同士の間隔）をｐとしたとき、ｐ×θｂ／３６０で規定される（図６の（３））。 If the lower stopper 25 is fixed to the guide bush 20 within the rotation angle θb [°] corresponding to this backlash, and the valve stem holder 30 is lowered while rotating using the screw feed mechanism 28, the valve stem holder 30 When the movable stopper body 34 and the fixed stopper body 24 of the lower stopper 25 are brought into contact, the lowest moving position of the valve stem holder 30 will gradually rise in accordance with the amount of rotation of the lower stopper 25. For example, when the thread pitch (distance between threads) of the female threaded portion 26 of the lower stopper 25 is p, the amount of rise Hb of the lowest position of the valve stem holder 30 at the time of backlash cancellation is p×θb/360. ((3) in FIG. 6).

バックラッシが相殺された後（下部ストッパ２５の回転角度がバックラッシ分の回転角度θｂ[°]に到達した後）（この状態では、下部ストッパ２５の雌ねじ部２６の下面側とガイドブッシュ２０の固定ねじ部２３の上面側とが接触）、下部ストッパ２５を開弁方向に更に回転させると、下部ストッパ２５は回転しながら上昇し始め、下部ストッパ２５とガイドブッシュ２０のストッパ部２７ａとの間に隙間ｈが形成される。 After the backlash is canceled out (after the rotation angle of the lower stopper 25 reaches the rotation angle θb [°] corresponding to the backlash) (in this state, the lower surface side of the female threaded portion 26 of the lower stopper 25 and the fixing screw of the guide bush 20 When the lower stopper 25 is further rotated in the valve opening direction, the lower stopper 25 begins to rise while rotating, and a gap is created between the lower stopper 25 and the stopper part 27a of the guide bush 20. h is formed.

最終的に、下部ストッパ２５をガイドブッシュ２０のストッパ部２７ａと当接させて締め込んだ状態から回転角度θ[°]だけ開弁方向に回転させてガイドブッシュ２０に固定したとすると、弁軸ホルダ３０の最下降位置は、ｐ×θ／３６０で規定される上昇量Ｈだけ上昇するため、弁軸ホルダ３０が最下動位置にあるとき（つまり、弁体１４が最下降位置にあるとき）に、弁体１４と弁シート部４６ａとの間に、（正方向流れ状態での）昇降方向における所定の寸法Ｈの間隙が形成される（図２（Ａ）参照）。一方で、下部ストッパ２５とガイドブッシュ２０のストッパ部２７ａとの間には、前記上昇量Ｈからバックラッシ分を差し引いた隙間ｈ、すなわち、ｐ×（θ－θｂ）／３６０で規定される隙間ｈが形成される。 Finally, if the lower stopper 25 is brought into contact with the stopper portion 27a of the guide bush 20 and tightened, then the lower stopper 25 is rotated in the valve opening direction by a rotation angle θ[°] and fixed to the guide bush 20. The lowest position of the holder 30 rises by the rising amount H defined by p×θ/360, so when the valve stem holder 30 is at the lowest moving position (that is, when the valve body 14 is at the lowest position) ), a gap having a predetermined dimension H in the vertical direction (in the forward flow state) is formed between the valve body 14 and the valve seat portion 46a (see FIG. 2(A)). On the other hand, there is a gap h between the lower stopper 25 and the stopper part 27a of the guide bush 20, which is determined by subtracting the amount of backlash from the amount of rise H, that is, a gap h defined by p×(θ−θb)/360. is formed.

なお、図示実施形態では、下部ストッパ２５をバックラッシ分の回転角度θｂ[°]を超えて回転させることで、下部ストッパ２５とガイドブッシュ２０のストッパ部２７ａとの間に隙間ｈが形成されているが、弁体１４と弁シート部４６ａとの間に形成される間隙の昇降方向における寸法が上記Ｈｂ以下に設定される場合には、下部ストッパ２５はバックラッシの回転角度θｂ[°]の範囲内で回転すればよいので、下部ストッパ２５とガイドブッシュ２０のストッパ部２７ａとの間に隙間は形成されず、下部ストッパ２５（の下面）はガイドブッシュ２０のストッパ部２７ａと当接したままとなる。 In the illustrated embodiment, a gap h is formed between the lower stopper 25 and the stopper portion 27a of the guide bush 20 by rotating the lower stopper 25 beyond the rotation angle θb [°] for backlash. However, when the dimension in the vertical direction of the gap formed between the valve body 14 and the valve seat portion 46a is set to be less than or equal to the above Hb, the lower stopper 25 is moved within the range of the backlash rotation angle θb [°]. Therefore, no gap is formed between the lower stopper 25 and the stopper portion 27a of the guide bush 20, and the lower stopper 25 (lower surface) remains in contact with the stopper portion 27a of the guide bush 20. .

また、上記の実施形態では、下部ストッパ２５をガイドブッシュ２０のストッパ部２７ａと当接させて締め込んだ状態を、下部ストッパ２５の開弁方向への回転の基準状態としたが、その基準状態における下部ストッパ２５の締結状態や上下方向における位置は、図示実施形態に限定されないことは当然である。例えば、下部ストッパ２５は、図６の（１）～（３）に示すバックラッシ分の回転角度の範囲内における如何なる状態を基準状態としてもよい。また、当該下部ストッパ２５は、その基準状態においてガイドブッシュ２０のストッパ部２７ａと当接している必要はなく、例えば図６の（４）に示すような、ガイドブッシュ２０（の固定ねじ部２３）における如何なる位置を基準状態としてもよい。なお、下部ストッパ２５がガイドブッシュ２０のストッパ部２７ａと離間している（当接していない）状態を前記基準状態とする場合、上記バックラッシは存在しなくなり、組立完了後において、弁体１４と弁シート部４６ａとの間に形成される間隙の昇降方向における寸法Ｈは、下部ストッパ２５（の下面）とガイドブッシュ２０のストッパ部２７ａとの隙間ｈより小さくなる（言い換えれば、下部ストッパ２５とガイドブッシュ２０のストッパ部２７ａの昇降方向における隙間ｈが、前記寸法Ｈより大きくなる）。 Further, in the above embodiment, the state in which the lower stopper 25 is brought into contact with the stopper portion 27a of the guide bush 20 and tightened is the reference state for the rotation of the lower stopper 25 in the valve opening direction. It goes without saying that the fastened state of the lower stopper 25 and the position in the vertical direction are not limited to the illustrated embodiment. For example, the lower stopper 25 may have any state within the range of rotation angles corresponding to the backlash shown in (1) to (3) of FIG. 6 as the reference state. Further, the lower stopper 25 does not need to be in contact with the stopper part 27a of the guide bush 20 in its standard state, and for example, as shown in (4) of FIG. Any position in can be used as the reference state. Note that if the reference state is a state in which the lower stopper 25 is separated from (does not contact) the stopper portion 27a of the guide bush 20, the backlash will no longer exist, and after the assembly is completed, the valve body 14 and the valve The dimension H in the vertical direction of the gap formed between the seat portion 46a and the guide bushing 20 is smaller than the gap h between the lower stopper 25 (lower surface) and the stopper portion 27a of the guide bush 20 (in other words, the distance between the lower stopper 25 and the guide The gap h in the vertical direction of the stopper portion 27a of the bush 20 is larger than the dimension H).

かかる組立方法により組み立てられた電動弁１では、上述したように、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と弁シート部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。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でも、弁体１４と弁シート部４６ａとの間に間隙（閉弁時要求リフト量）が形成されるため、所定量の通過流量が確保される（図３参照）。 In the electric valve 1 assembled by this assembly method, as described above, when the rotor 51 is rotated by energizing the stator 52 (the stator coil 52c thereof), the valve stem holder 30 and the valve stem 10 are integrally rotated. It is made to rotate. At this time, the valve stem 10 is raised and lowered together with the valve body 14 by the screw feeding mechanism 28 consisting of the fixed screw portion 23 of the guide bush 20 and the movable screw portion 33 of the valve stem holder 30. The gap (lift amount, valve opening degree) between the valve seat portion 46a and the valve seat portion 46a is increased or decreased to adjust the flow rate of fluid such as refrigerant. Further, the movable stopper body 34 of the valve stem 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 even when the valve body 14 is in the lowest position, the valve body 14 and the valve seat Since a gap (required lift amount when closing the valve) is formed between the valve and the portion 46a, a predetermined amount of flow rate is ensured (see FIG. 3).

本実施形態の電動弁１においては、ねじピッチｐの雌ねじ部２６を持つ下部ストッパ２５がガイドブッシュ２０の所定位置に相対回転可能に螺合され、下部ストッパ機構２９により弁軸ホルダ３０が最下動位置に位置せしめられるとともに、弁体１４を最下降位置より下降せしめて弁体１４の環状平坦面１４ｆを弁本体４０の環状平坦面４５ｆに当接させ、その後、弁体１４の環状平坦面１４ｆが弁本体４０の環状平坦面４５ｆに当接した位置を基準として、前記所定位置にある下部ストッパ２５をガイドブッシュ２０に対して開弁方向に所定回転角度θだけ回転させて該ガイドブッシュ２５に相対回転不能に連結すると、下部ストッパ機構２９により弁軸ホルダ３０が最下動位置にあるときに、弁体１４と弁シート部４６ａとの間（具体的には、環状平坦面１４ｆと環状平坦面４５ｆとの間）に、正方向流れ状態での昇降方向における寸法Ｈがｐ×θ／３６０で規定される間隙が形成されるとともに、弁体１４におけるストレート部１４ｓの少なくとも一部と弁シート部４６ａにおけるストレート部４６ｓの少なくとも一部とが昇降方向で重なるようになっている。つまり、下部ストッパ２５がガイドブッシュ２０に対して開弁方向に回転された後に当該ガイドブッシュ２０に相対回転不能に連結されることにより、正方向流れ状態での弁体１４の最下降位置、言い換えれば弁体１４が最下降位置にあるときの弁体１４と弁シート部４６ａとの間の昇降方向における間隙が規定される。すなわち、原点位置における弁体１４と弁シート部４６ａとの間の間隙の寸法精度が、基本的に下部ストッパ機構２９を構成する下部ストッパ２５の雌ねじ部２６とガイドブッシュ２０の固定ねじ部２３の寸法精度に依存することとなるため、前記間隙の寸法ばらつきを抑えることができ、もって、低流量域における流体（冷媒）流量の制御性を向上させることができる。さらに、弁体１４におけるストレート部１４ｓの上側に設けられた環状平坦面１４ｆ及び弁本体４０の環状平坦面４５ｆを弁体１４の組立時の原点位置出しの基準面としたことで、原点位置における弁体１４と弁シート部４６ａとの間の間隙の寸法精度が、基本的に弁体１４の環状平坦面１４ｆの部品精度（加工精度）に依存することとなり、前記間隙の寸法ばらつき、ひいては、流量特性（例えば、中間開度での流量の変曲点）のばらつきを効果的に抑えることができる。 In the electric valve 1 of this embodiment, a lower stopper 25 having a female threaded portion 26 with a thread pitch p is screwed into a predetermined position of the guide bush 20 so as to be relatively rotatable, and the lower stopper mechanism 29 allows the valve stem holder 30 to be moved to the lowest position. At the same time, the valve body 14 is lowered from the lowest position to bring the annular flat surface 14f of the valve body 14 into contact with the annular flat surface 45f of the valve body 40, and then the annular flat surface of the valve body 14 The lower stopper 25 at the predetermined position is rotated by a predetermined rotation angle θ in the valve opening direction with respect to the guide bush 20, with reference to the position where the annular flat surface 45f of the valve body 40 contacts the guide bush 25. When the lower stopper mechanism 29 connects the valve shaft holder 30 to the lowest position, the valve body 14 and the valve seat 46a (specifically, the annular flat surface 14f and the annular A gap whose dimension H in the vertical direction in the forward flow state is defined as p×θ/360 is formed between the flat surface 45f and at least a portion of the straight portion 14s of the valve body 14 and the valve body 14. At least a portion of the straight portion 46s of the seat portion 46a overlaps in the vertical direction. That is, after the lower stopper 25 is rotated in the valve opening direction with respect to the guide bush 20, it is connected to the guide bush 20 in a relatively non-rotatable manner, so that the lowermost position of the valve body 14 in the forward flow state, in other words, For example, the gap in the vertical direction between the valve body 14 and the valve seat portion 46a when the valve body 14 is in the lowest position is defined. That is, the dimensional accuracy of the gap between the valve body 14 and the valve seat portion 46a at the origin position basically depends on the female threaded portion 26 of the lower stopper 25 and the fixed threaded portion 23 of the guide bush 20, which constitute the lower stopper mechanism 29. Since this depends on dimensional accuracy, it is possible to suppress dimensional variations in the gap, thereby improving the controllability of the fluid (refrigerant) flow rate in a low flow rate region. Furthermore, by using the annular flat surface 14f provided on the upper side of the straight portion 14s of the valve body 14 and the annular flat surface 45f of the valve body 40 as reference surfaces for determining the origin position when assembling the valve body 14, the origin position can be determined. The dimensional accuracy of the gap between the valve body 14 and the valve seat portion 46a basically depends on the component accuracy (machining accuracy) of the annular flat surface 14f of the valve body 14, resulting in dimensional variations in the gap and, by extension, Variations in flow characteristics (for example, inflection point of flow rate at intermediate opening degrees) can be effectively suppressed.

１ 電動弁
１０ 弁軸
１４ 弁体
１４ｆ 環状平坦面（弁体側当接部）
１４ｓ 弁体側ストレート部
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 底部壁
４５ｆ 環状平坦面（本体側当接部）
４６ 弁口オリフィス
４６ａ 弁シート部
４６ｓ 弁シート側ストレート部
４７ 鍔状部
４８ シート部材
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 1 Electric valve 10 Valve shaft 14 Valve body 14f Annular flat surface (valve body side contact part)
14s Valve body side straight part 20 Guide bush 21 Cylindrical part 23 Fixing thread part (male thread part)
28 Screw feed mechanism 29 Lower stopper mechanism 30 Valve shaft holder 33 Movable threaded part (female threaded part)
40 Valve body 40a Valve chamber 41 First opening 41a First conduit 42 Second opening 42a Second conduit 45 Bottom wall 45f Annular flat surface (body side contact part)
46 Valve orifice 46a Valve seat part 46s Valve seat side straight part 47 Flange-shaped part 48 Seat member 50 Stepping motor 51 Rotor 52 Stator 55 Can 60 Compression coil spring 70 Removal prevention locking member O Axis

Claims (3)

弁軸の先端に設けられた弁体と、前記弁体の下動規制を行うための下部ストッパ機構と、前記弁体が接離又は近接離間する弁シート部を有する弁口オリフィスが設けられた弁本体と、を有し、
ロータの回転運動を、雄ネジ部材と雌ネジ部材とのネジ螺合により直線運動に変換し、この直線運動に基づいて前記弁体を前記弁シート部に接離又は近接離間する方向に移動させ、
前記下部ストッパ機構により前記弁体が最下降位置にあるときに、所定量の流体が通過するように、前記弁シート部と前記弁体との間に間隙が形成される電動弁であって、
前記弁体は、前記弁口オリフィスに挿入したときに前記弁口オリフィスの内周面との間に微小な隙間を形成し、前記弁口オリフィスの軸線と平行な外周面を有する弁体側ストレート部と、前記弁体側ストレート部の先端と連続して形成されたテーパ状の外周面を有するテーパ面部とを備え、
前記弁体側ストレート部は、前記弁軸と前記テーパ面部との間に形成され、
前記弁体側ストレート部の前記軸線の方向の長さは、前記弁体側ストレート部の直径よりも短く、
前記弁体が前記最下降位置にあるとき、前記弁口オリフィスに挿入された前記弁体側ストレート部の軸方向の長さは、前記ネジ螺合時のネジガタ分の軸方向の長さよりも長く形成されることを特徴とする電動弁。 A valve orifice having a valve body provided at the tip of a valve shaft, a lower stopper mechanism for restricting downward movement of the valve body, and a valve seat portion through which the valve body approaches and separates or approaches and separates. a valve body;
The rotary motion of the rotor is converted into a linear motion by screwing the male threaded member and the female threaded member, and based on this linear motion, the valve body is moved in the direction of approaching and separating from or approaching the valve seat portion. ,
An electric valve in which a gap is formed between the valve seat portion and the valve body so that a predetermined amount of fluid passes through when the valve body is in the lowest position due to the lower stopper mechanism,
The valve body has a straight portion on the valve body side that forms a minute gap between the valve body and the inner circumferential surface of the valve orifice when inserted into the valve orifice, and has an outer circumferential surface parallel to the axis of the valve orifice. and a tapered surface portion having a tapered outer peripheral surface formed continuously with the tip of the valve body side straight portion,
The valve body side straight part is formed between the valve shaft and the tapered surface part,
The length of the valve body side straight part in the direction of the axis is shorter than the diameter of the valve body side straight part,
When the valve body is in the lowest position, the axial length of the valve body side straight portion inserted into the valve port orifice is longer than the axial length corresponding to the screw play when the screws are screwed together. An electric valve characterized by: 前記弁口オリフィスは、円筒面からなる弁シート側ストレート部を有することを特徴とする請求項１に記載の電動弁。 The motor-operated valve according to claim 1, wherein the valve orifice has a valve seat-side straight portion having a cylindrical surface. 前記下部ストッパ機構により前記弁体が最下降位置にあるときに、前記弁体側ストレート部と前記テーパ面部の境界の前記軸線の方向の位置が、前記弁シート側ストレート部の内周面の高さの範囲内に位置することを特徴とする請求項２に記載の電動弁。 When the valve body is in the lowest position due to the lower stopper mechanism, the position of the boundary between the valve body side straight part and the tapered surface part in the direction of the axis is equal to the height of the inner circumferential surface of the valve seat side straight part. The electric valve according to claim 2, wherein the electric valve is located within a range of .
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