JP7499830B2

JP7499830B2 - Welded construction

Info

Publication number: JP7499830B2
Application number: JP2022201071A
Authority: JP
Inventors: 祐成室屋; 一徳南波佐間; 文雄金崎; 佳祐村田; 理宮川; 龍介鈴木
Original assignee: Saginomiya Seisakusho Inc
Current assignee: Saginomiya Seisakusho Inc
Priority date: 2019-03-19
Filing date: 2022-12-16
Publication date: 2024-06-14
Anticipated expiration: 2039-03-19
Also published as: JP2023026492A; JP7324018B2; JP2020153418A; JP2024107046A

Description

本発明は、弁室内に設けられる弁体と、弁室をシールするダイヤフラムと、を備えた弁装置における弁体とダイヤフラムとを溶接接合するための溶接構造に関する。 The present invention relates to a welding structure for welding and joining a valve body and a diaphragm in a valve device that includes a valve body provided in a valve chamber and a diaphragm that seals the valve chamber.

従来、例えば、冷凍空調装置等に利用される弁装置において、弁室をシールするためのシール部材として、金属ダイヤフラムが利用されている。（例えば、特許文献１参照）。特許文献１に記載された弁装置（ダイヤフラム弁）は、弁室および弁口（弁座）を有する弁本体（ボディおよびボンネット）と、弁室内に進退自在に設けられる弁体（ステムおよびディスク）と、弁本体と弁体とに亘って設けられて弁室をシールする金属ダイヤフラムと、を備えている。金属ダイヤフラムは、全体円盤状（皿状）の薄板材で形成され、中央部に弁体の軸部を挿通させる挿通孔（取り付け穴）が形成されている。金属ダイヤフラムの外周縁部は、弁本体に挟持されて固定され、内周縁部は、弁体の軸部に溶接されて固着されている。 Conventionally, in valve devices used in, for example, refrigeration and air conditioning devices, metal diaphragms are used as sealing members for sealing valve chambers (see, for example, Patent Document 1). The valve device (diaphragm valve) described in Patent Document 1 includes a valve body (body and bonnet) having a valve chamber and a valve port (valve seat), a valve element (stem and disk) that is provided so as to be movable forward and backward within the valve chamber, and a metal diaphragm that is provided across the valve body and the valve element and seals the valve chamber. The metal diaphragm is formed from a thin plate material that is entirely disc-shaped (dish-shaped), and has an insertion hole (mounting hole) formed in the center through which the shaft of the valve element is inserted. The outer peripheral edge of the metal diaphragm is clamped and fixed to the valve body, and the inner peripheral edge is welded and fixed to the shaft of the valve element.

ところで、冷媒等の高温、高圧流体の流量等を制御する弁装置において、金属ダイヤフラムの金属素材としては耐熱性や耐蝕性に優れたステンレス合金やニッケル基合金が用いられ、その溶接対象物である弁体の金属素材としてはステンレス合金が用いられることがある。特に、ステンレス合金としては、オーステナイト系ステンレス鋼（例えば、ＳＵＳ３１６Ｌなど）が用いられ、ニッケル基合金としては、耐熱性、耐蝕性、耐酸化性などに優れたインコネル（登録商標。例えば、インコネル６２５など）が用いられることがあり、加工性や材料コスト等の要因から部位ごとに異なる金属素材が適宜に選択され、その異種金属素材同士が溶接されることがある。 In valve devices that control the flow rate of high-temperature, high-pressure fluids such as refrigerants, stainless steel alloys and nickel-based alloys, which have excellent heat and corrosion resistance, are used as the metal material for the metal diaphragm, and stainless steel alloys are sometimes used as the metal material for the valve body, which is the object to be welded. In particular, austenitic stainless steel (e.g., SUS316L, etc.) is used as the stainless steel alloy, and Inconel (registered trademark, e.g., Inconel 625, etc.), which has excellent heat resistance, corrosion resistance, and oxidation resistance, is sometimes used as the nickel-based alloy. Different metal materials are appropriately selected for each part based on factors such as workability and material cost, and these dissimilar metal materials are sometimes welded together.

特開平８－２１９３０３号公報Japanese Patent Application Laid-Open No. 8-219303

しかしながら、オーステナイト系ステンレス鋼は、一般的に溶接割れを起こしやすい金属素材であることが知られており、オーステナイト系ステンレス鋼とニッケル基合金等との異種金属素材同士の溶接においても、溶接欠陥が生じやすいことが予想される。特に、薄板材からなる金属ダイヤフラムを肉厚な弁体等に溶接する際に、金属ダイヤフラムを板厚方向に貫通して弁体の内部に至るような溶接部が形成されると、溶融金属が固化するときの収縮が拘束されることから、溶接固化部に引張応力が作用して割れが発生しやすくなる。このため、金属ダイヤフラムと弁体等との異種金属素材同士の溶接部における溶接割れを防止しつつ、溶接耐久性を向上させることができる溶接構造が求められていた。 However, austenitic stainless steel is generally known to be a metal material susceptible to weld cracks, and welding defects are expected to occur easily when welding dissimilar metal materials, such as austenitic stainless steel and nickel-based alloys. In particular, when welding a metal diaphragm made of a thin plate material to a thick valve body, if a weld is formed that penetrates the metal diaphragm in the plate thickness direction and reaches the inside of the valve body, the contraction of the molten metal when solidifying is restricted, and tensile stress acts on the solidified weld, making it more likely to cause cracks. For this reason, there has been a demand for a welding structure that can prevent weld cracks in the weld between dissimilar metal materials, such as a metal diaphragm and a valve body, while improving weld durability.

本発明の目的は、弁装置における弁体とダイヤフラムとを溶接接合する際の溶接割れを防止しつつ、溶接耐久性を向上させることができる溶接構造を提供することである。 The object of the present invention is to provide a welded structure that can improve weld durability while preventing weld cracks when welding the valve body and diaphragm in a valve device.

本発明の溶接構造は、弁室内に設けられる弁体と、前記弁室をシールするダイヤフラムと、を備えた弁装置における前記弁体と前記ダイヤフラムとを溶接接合するための溶接構造であって、前記弁体は、円柱状の軸部を有し、前記ダイヤフラムは、１又は複数の薄板材で構成されるとともに、前記軸部を挿通させる挿通孔を有して構成され、前記軸部には、第一面と、その反対側の第二面と、を有して軸方向に突出するとともに、周方向に連続した環状の接続部が設けられ、前記ダイヤフラムの前記挿通孔には、前記接続部の前記第一面に沿って軸方向に延びるとともに、周方向に連続した環状の被溶接部が設けられ、前記接続部および前記被溶接部は、互いの先端部同士が溶接されて断面円形の溶融固化部によって接合されていることを特徴とする。 The welded structure of the present invention is a welded structure for welding and joining a valve body and a diaphragm in a valve device that includes a valve body provided in a valve chamber and a diaphragm that seals the valve chamber, the valve body having a cylindrical shaft portion, the diaphragm being made of one or more thin plate materials and having an insertion hole through which the shaft portion is inserted, the shaft portion having a first surface and a second surface opposite thereto, protruding in the axial direction, and provided with a circumferentially continuous annular connecting portion, the insertion hole of the diaphragm being provided with a circumferentially continuous annular welded portion that extends in the axial direction along the first surface of the connecting portion, and the connecting portion and the welded portion are welded to each other at their respective tips and joined by a molten solidified portion having a circular cross section.

以上のような本発明によれば、弁体の軸部に設けた接続部およびダイヤフラムの挿通孔に設けた被溶接部の先端部に断面円形の溶融固化部が形成されていることで、溶接割れを防止することができる。すなわち、接続部および被溶接部の先端部同士を溶接することで、溶融した金属が表面張力で円形（溶接部が点であれば球状）となり、凝固する過程で収縮したとしても、その収縮力が母材に作用しにくくなり、収縮による引張応力の発生を抑制することができる。従って、溶融固化部や周辺の母材における溶接割れを防止することができ、残留応力を抑制することによって溶接耐久性を向上させることができる。また、溶融固化部が周方向に連続した環状に形成され、この溶融固化部の溶接耐久性が向上することで、ダイヤフラムによる良好なシール性が維持されることから弁装置の製品寿命を延ばすことができる。 According to the present invention, the molten solidified portion having a circular cross section is formed at the tip of the welded portion provided in the connection portion provided on the shaft portion of the valve body and the insertion hole of the diaphragm, thereby preventing weld cracks. In other words, by welding the tip of the connection portion and the welded portion together, the molten metal becomes circular (spherical if the welded portion is a point) due to surface tension, and even if it shrinks during the solidification process, the contraction force is less likely to act on the base material, and the generation of tensile stress due to shrinkage can be suppressed. Therefore, weld cracks can be prevented in the molten solidified portion and the surrounding base material, and the welding durability can be improved by suppressing residual stress. In addition, the molten solidified portion is formed in a continuous ring shape in the circumferential direction, and the welding durability of this molten solidified portion is improved, so that good sealing properties by the diaphragm are maintained, and the product life of the valve device can be extended.

この際、前記溶融固化部の直径は、前記接続部の先端側および前記被溶接部を合せた厚み寸法以上であることが好ましい。 In this case, it is preferable that the diameter of the molten and solidified portion is equal to or greater than the combined thickness of the tip side of the connection portion and the welded portion.

この構成によれば、溶融固化部が接続部の先端側および被溶接部を合せた厚み寸法以上の直径を有する断面円形に形成されることで、溶融固化部と被溶接部および接続部とを滑らかに連続させ、被溶接部や接続部の先端にエッジが残らないようにすることができる。 With this configuration, the molten and solidified portion is formed into a circular cross section with a diameter equal to or greater than the combined thickness of the tip of the connection portion and the welded portion, allowing the molten and solidified portion to be smoothly continuous with the welded portion and connection portion, and preventing edges from remaining at the tips of the welded portion and connection portion.

さらに、前記接続部の先端側および前記被溶接部の先端側の厚み寸法は、互いに同程度であることが好ましい。 Furthermore, it is preferable that the thickness dimensions of the tip side of the connection part and the tip side of the welded part are approximately the same.

この構成によれば、互いに同程度の厚み寸法を有する接続部および被溶接部の先端部を溶接することで、溶接時の溶融金属量を同等にするとともに、生じる熱や応力を均等化することができ、母材に与える熱や応力の影響を抑制して溶接割れを防止することができる。 According to this configuration, by welding the tip of the connection part and the welded part, which have approximately the same thickness dimension, the amount of molten metal during welding can be made equal and the heat and stress generated can be equalized, suppressing the effects of heat and stress on the base material and preventing weld cracks.

また、前記弁体の前記軸部は、主としてオーステナイト系ステンレス鋼からなり、前記ダイヤフラムの薄板材は、主としてニッケル基合金からなってもよい。 The shaft portion of the valve body may be made primarily of austenitic stainless steel, and the thin plate material of the diaphragm may be made primarily of a nickel-based alloy.

この構成によれば、弁体の軸部およびダイヤフラムの薄板材がオーステナイト系ステンレス鋼とニッケル基合金とからなる異種金属素材同士であり、溶融固化部や周辺の母材に溶接割れが生じやすい条件であっても、溶接割れを防止することができる。 With this configuration, the stem of the valve body and the thin plate material of the diaphragm are made of dissimilar metal materials, austenitic stainless steel and nickel-based alloy, and weld cracks can be prevented even under conditions that tend to cause weld cracks in the melted and solidified portion and the surrounding base material.

また、前記溶融固化部の直径は、前記接続部の先端側および前記被溶接部を合せた厚み寸法に対し、１．１倍以上かつ１．６倍以下であることが好ましい。 It is also preferable that the diameter of the molten and solidified portion is 1.1 times or more and 1.6 times or less than the combined thickness dimension of the tip side of the connection portion and the welded portion.

この構成によれば、溶融固化部の直径が接続部の先端側および被溶接部を合せた厚み寸法に対して１．１倍以上かつ１．６倍以下に設定されることで、被溶接部や接続部の先端にエッジが残らず、溶接部の溶接耐久性や力学特性を向上させることができる。 With this configuration, the diameter of the molten and solidified portion is set to 1.1 times or more and 1.6 times or less than the combined thickness dimension of the tip side of the connection portion and the welded portion, so that no edges remain at the tip of the welded portion or the connection portion, improving the welding durability and mechanical properties of the welded portion.

さらに、前記接続部における前記第一面と前記第二面とは、当該接続部の先端に向かって狭まる交差角度を有して設けられ、前記交差角度が４０°以下であることが好ましい。 Furthermore, the first surface and the second surface of the connection portion are provided with an intersection angle that narrows toward the tip of the connection portion, and it is preferable that the intersection angle is 40° or less.

この構成によれば、接続部における第一面と第二面とが先端に向かって狭まる４０°以下の交差角度で設けられていることで、溶融金属が凝固する際の収縮力が母材に与える影響を抑制し、接続部の溶接割れを防止することができる。 With this configuration, the first and second surfaces of the connection are arranged at an intersection angle of 40° or less that narrows toward the tip, which reduces the effect on the base material of the contraction force caused when the molten metal solidifies, and prevents weld cracks in the connection.

また、前記被溶接部は、前記ダイヤフラムを構成する薄板材の端部を折り返して重ねた折返部によって構成され、前記薄板材の端縁側が前記接続部の前記第一面に沿って設けられていることが好ましい。 It is also preferable that the welded portion is formed by folding back an end of the thin plate material that constitutes the diaphragm, and that the edge side of the thin plate material is provided along the first surface of the connection portion.

この構成によれば、薄板材の端部を折り返して重ねた折返部によってダイヤフラムの被溶接部を構成することで、被溶接部の厚み寸法が大きくなり、溶接時の熱の影響や凝固する際の収縮力の影響を抑制し、被溶接部の溶接割れを防止することができる。 According to this configuration, the welded portion of the diaphragm is formed by folding back the end of the thin plate material, which increases the thickness of the welded portion, suppressing the effects of heat during welding and the effects of contraction forces during solidification, and preventing weld cracks in the welded portion.

本発明の溶接構造によれば、ダイヤフラムと弁体との溶接部における溶接割れを防止しつつ、溶接耐久性を向上させることができ、弁装置の製品寿命を延ばすことができる。 The welded structure of the present invention can prevent weld cracks at the welded joint between the diaphragm and the valve body while improving weld durability, thereby extending the product life of the valve device.

本発明の第１実施形態に係る溶接構造を用いた弁装置を示す断面図である。1 is a cross-sectional view showing a valve device using a welded structure according to a first embodiment of the present invention. 前記弁装置の要部を示す拡大断面図である。FIG. 2 is an enlarged cross-sectional view showing a main portion of the valve device. 前記弁装置における溶接構造を示す拡大断面図である。FIG. 4 is an enlarged cross-sectional view showing a welding structure in the valve device. 前記弁装置における溶接構造の変形例を示す拡大断面図である。5 is an enlarged cross-sectional view showing a modified example of the welding structure in the valve device. FIG. 本発明の第２実施形態に係る溶接構造を用いた弁装置を示す断面図である。FIG. 6 is a cross-sectional view showing a valve device using a welded structure according to a second embodiment of the present invention. 前記弁装置の要部を示す拡大断面図である。FIG. 2 is an enlarged cross-sectional view showing a main portion of the valve device. 前記弁装置における溶接構造を示す拡大断面図である。FIG. 4 is an enlarged cross-sectional view showing a welding structure in the valve device. 本発明の第１の変形例の溶接構造を示す拡大断面図である。FIG. 4 is an enlarged cross-sectional view showing a welded structure according to a first modified example of the present invention. 本発明の第２の変形例の溶接構造を示す拡大断面図である。FIG. 4 is an enlarged cross-sectional view showing a welded structure according to a second modified example of the present invention. 本発明の第３の変形例の溶接構造を示す拡大断面図である。FIG. 11 is an enlarged cross-sectional view showing a welded structure according to a third modified example of the present invention. 本発明の第４の変形例の溶接構造を示す拡大断面図である。FIG. 13 is an enlarged cross-sectional view showing a welded structure according to a fourth modified example of the present invention.

本発明の第１実施形態に係る溶接構造を用いた弁装置について、図１～図４を参照して説明する。本実施形態の弁装置は、変位可能なシール部材である金属ダイヤフラムを備えたものである。図１は、実施形態の弁装置であるダイヤフラム弁１０を示す断面図である。図２は、ダイヤフラム弁１０の要部を示す拡大断面図であり、図１に丸囲み部Ａで示す部分の拡大図である。図３は、ダイヤフラム弁１０における溶接構造を示す拡大断面図であり、図２に丸囲み部Ｂで示す部分の拡大図である。また、図３（Ａ）は溶接接合された弁体およびダイヤフラムの要部を示し、図３（Ｂ）は弁体およびダイヤフラムの溶接接合前の状態を示している。 A valve device using a welded structure according to a first embodiment of the present invention will be described with reference to Figs. 1 to 4. The valve device of this embodiment is equipped with a metal diaphragm, which is a displaceable sealing member. Fig. 1 is a cross-sectional view showing a diaphragm valve 10, which is a valve device of the embodiment. Fig. 2 is an enlarged cross-sectional view showing the main parts of the diaphragm valve 10, and is an enlarged view of the part indicated by the circled part A in Fig. 1. Fig. 3 is an enlarged cross-sectional view showing the welded structure of the diaphragm valve 10, and is an enlarged view of the part indicated by the circled part B in Fig. 2. Fig. 3(A) shows the main parts of the valve body and diaphragm that have been welded together, and Fig. 3(B) shows the state of the valve body and diaphragm before they are welded together.

ダイヤフラム弁１０は、図１に示すように、内部に弁室１１を有する弁本体（ボディ）１２と、弁室１１内に設けられた弁体１３と、弁体１３を進退移動させるために回転操作される操作部１４と、弁室１１の内部をシールする金属ダイヤフラム１５と、を備えた手動開閉タイプのバルブである。弁本体１２は、互いに螺合される第１部材１２ａおよび第２部材１２ｂを備え、第１部材１２ａと第２部材１２ｂとの面合せ部に金属ダイヤフラム１５の外周縁が挟持されている。 As shown in Figure 1, the diaphragm valve 10 is a manually opened and closed valve that includes a valve body 12 having a valve chamber 11 therein, a valve element 13 provided in the valve chamber 11, an operating part 14 that is rotated to move the valve element 13 back and forth, and a metal diaphragm 15 that seals the inside of the valve chamber 11. The valve body 12 includes a first member 12a and a second member 12b that are screwed together, and the outer periphery of the metal diaphragm 15 is clamped at the face-to-face portion of the first member 12a and the second member 12b.

弁本体１２の第１部材１２ａは、その一端側に開口して弁室１１に連通する流入ポート１２ｃと、他端側に開口して弁室１１に連通する流出ポート１２ｄと、流入ポート１２ｃが弁室１１に開口した開口である弁ポート１２ｅと、を備える。弁本体１２の第２部材１２ｂは、全体円筒状に形成され、操作部１４の軸部１４ｂを回転支持する軸受部１２ｆと、軸部１４ｂの雄ねじ部１４ｃと螺合する雌ねじ部１２ｇと、を備えて構成されている。 The first member 12a of the valve body 12 has an inlet port 12c that opens at one end and communicates with the valve chamber 11, an outlet port 12d that opens at the other end and communicates with the valve chamber 11, and a valve port 12e that is an opening of the inlet port 12c into the valve chamber 11. The second member 12b of the valve body 12 is formed in an entirely cylindrical shape and is configured with a bearing portion 12f that rotatably supports the shaft portion 14b of the operating portion 14, and a female thread portion 12g that screws into the male thread portion 14c of the shaft portion 14b.

弁体１３は、図２に示すように、上下にフランジを有した円筒状の弁体ケース１３ａと、弁体ケース１３ａの内部に保持された弁部材１３ｂと、弁部材１３ｂよりも上側にて弁体ケース１３ａに保持された連結部材１３ｃと、連結部材１３ｃの上面の凹穴に設けられた球体１３ｄと、を有して構成されている。弁部材１３ｂは、樹脂製やゴム製のパッキン
であって、弁ポート１２ｅに着座して密閉可能に構成されている。連結部材１３ｃは、弁体ケース１３ａよりも上方に延びる円柱状の軸部１３ｅを有し、この軸部１３ｅに金属ダイヤフラム１５が固定されている。球体１３ｄは、連結部材１３ｃの凹穴に転動自在に支持されるとともに、上方から当接する操作部１４の当接部１４ｄと連結部材１３ｃとの間に挟まれている。この球体１３ｄによって操作部１４の中心軸Ｘ回りの回転や弁体１３の傾き等が吸収されることで、操作部１４からの下向きの押圧力だけが球体１３ｄを介して弁体１３に伝達されるようになっている。 As shown in Fig. 2, the valve body 13 is composed of a cylindrical valve body case 13a having flanges on the top and bottom, a valve member 13b held inside the valve body case 13a, a connecting member 13c held in the valve body case 13a above the valve member 13b, and a ball 13d provided in a recessed hole on the upper surface of the connecting member 13c. The valve member 13b is a resin or rubber packing and is configured to be able to seat on the valve port 12e and seal it. The connecting member 13c has a cylindrical shaft portion 13e extending above the valve body case 13a, and a metal diaphragm 15 is fixed to this shaft portion 13e. The ball 13d is supported in a recessed hole of the connecting member 13c so as to be able to roll freely, and is sandwiched between the connecting member 13c and an abutment portion 14d of the operating portion 14 that abuts against it from above. This sphere 13d absorbs the rotation of the operating unit 14 about the central axis X and the tilt of the valve body 13, so that only the downward pressing force from the operating unit 14 is transmitted to the valve body 13 via the sphere 13d.

操作部１４は、ハンドル１４ａと、ハンドル１４ａに上端部が固定されて軸方向に延びる軸部１４ｂと、軸部１４ｂに設けられた雄ねじ部１４ｃと、雄ねじ部１４ｃよりも下方の先端部に設けられた当接部１４ｄと、を備える。軸部１４ｂは、弁本体１２の軸受部１２ｆに回転支持され、雄ねじ部１４ｃは、雌ねじ部１２ｇに螺合されている。当接部１４ｄは、弁体１３の球体１３ｄに当接して設けられている。 The operating unit 14 comprises a handle 14a, a shaft portion 14b whose upper end is fixed to the handle 14a and extends in the axial direction, a male threaded portion 14c provided on the shaft portion 14b, and an abutment portion 14d provided on the tip portion below the male threaded portion 14c. The shaft portion 14b is rotatably supported by the bearing portion 12f of the valve body 12, and the male threaded portion 14c is screwed into the female threaded portion 12g. The abutment portion 14d is provided in abutment against the sphere 13d of the valve body 13.

金属ダイヤフラム１５は、１枚の全体円形板状（皿状）の金属薄板材からなり、中央部に弁体１３の軸部１３ｅを挿通させる挿通孔１５ａが形成されている。金属ダイヤフラム１５は、その外周縁が弁本体１２の第１部材１２ａと第２部材１２ｂとの間に挟持され、挿通孔１５ａの内周縁が弁体１３の軸部１３ｅに溶接固定されている。また、金属ダイヤフラム１５は、自身の弾性により面外方向に撓むことで弁体１３を上下移動自在に支持するとともに、図１、２に示すように、金属ダイヤフラム１５の弾性による上向きの付勢力が作用することで、弁体１３は、弁部材１３ｂが弁ポート１２ｅから離れた弁開位置にて支持されている。 The metal diaphragm 15 is made of a single circular (dish-shaped) thin metal plate, and has a through hole 15a in the center through which the shaft 13e of the valve body 13 passes. The outer periphery of the metal diaphragm 15 is sandwiched between the first member 12a and the second member 12b of the valve body 12, and the inner periphery of the through hole 15a is welded to the shaft 13e of the valve body 13. The metal diaphragm 15 supports the valve body 13 so that it can move up and down by bending in the out-of-plane direction due to its own elasticity, and as shown in Figures 1 and 2, the upward biasing force due to the elasticity of the metal diaphragm 15 acts on the valve body 13, supporting the valve member 13b in the valve open position away from the valve port 12e.

このようなダイヤフラム弁１０では、操作部１４のハンドル１４ａが回転操作されることで、雄ねじ部１３ｂが雌ねじ部１２ｇに案内されて操作部１４が上下移動し、この上下移動が当接部１４ｄおよび球体１３ｄを介して弁体１３に伝達される。ハンドル１４ａの閉操作により操作部１４が下方に移動すると、その押圧力によって金属ダイヤフラム１５を面外方向下向きに撓ませつつ弁体１３が下方に移動し、弁部材１３ｂが弁ポート１２ｅに着座する。ハンドル１４ａの開操作により操作部１４が上方に移動すると、金属ダイヤフラム１５が初期位置に復帰しようとする弾性力（復元力）によって弁部材１３ｂが上方に移動し、弁部材１３ｂが弁ポート１２ｅから離座する。このように弁部材１３ｂは、操作部１４のハンドル１４ａの操作に伴って弁閉位置と弁閉位置との間を上下方向に進退移動するようになっている。 In such a diaphragm valve 10, when the handle 14a of the operating part 14 is rotated, the male threaded part 13b is guided by the female threaded part 12g to move the operating part 14 up and down, and this up and down movement is transmitted to the valve body 13 via the abutment part 14d and the sphere 13d. When the operating part 14 is moved downward by closing the handle 14a, the metal diaphragm 15 is deflected downward out of the plane by the pressing force, and the valve body 13 moves downward, and the valve member 13b seats on the valve port 12e. When the operating part 14 is moved upward by opening the handle 14a, the valve member 13b moves upward due to the elastic force (restoring force) of the metal diaphragm 15 trying to return to its initial position, and the valve member 13b leaves the valve port 12e. In this way, the valve member 13b moves forward and backward in the up and down direction between the valve closed position and the valve closed position in accordance with the operation of the handle 14a of the operating part 14.

次に、図３を参照して金属ダイヤフラム１５と弁体１３の軸部１３ｅとの溶接構造について説明する。金属ダイヤフラム１５の厚み寸法ｔは、０．２ｍｍ～０．４ｍｍ程度であり、挿通孔１５ａ側の端部には、下方に向かって折り曲げられるとともに径方向の外側方向に延び、周方向に連続した環状の被溶接部１５ｂが設けられている。被溶接部１５ｂの厚み寸法ＴBは、金属ダイヤフラム１５の厚み寸法ｔと略同一（ＴB＝ｔ）の０．２ｍｍ～０．４ｍｍ程度となっている。 Next, the welded structure between the metal diaphragm 15 and the shaft portion 13e of the valve body 13 will be described with reference to Figure 3. The thickness dimension t of the metal diaphragm 15 is approximately 0.2 mm to 0.4 mm, and the end on the insertion hole 15a side is bent downward and extends radially outward, providing a circumferentially continuous ring-shaped welded portion 15b. The thickness dimension TB of the welded portion 15b is approximately 0.2 mm to 0.4 mm, which is approximately the same as the thickness dimension t of the metal diaphragm 15 (TB = t).

軸部１３ｅには、径方向の外側方向に突出した接続部１６が周方向に連続した環状に形成されている。接続部１６は、図３（Ｂ）に示すように、被溶接部１５ｂが沿う上側の第一面１６ａと、その反対側（下側）の第二面１６ｂと、接続部１６の先端側を構成する第三面１６ｃと、を有して突起状に形成され、第二面１６ｂが中心軸Ｘと略直交する面に沿って延び、この第二面１６ｂと第一面１６ａとの交差角度θが３０°程度になっている。接続部１６の先端側の厚み寸法ＴFと、被溶接部１５ｂの厚み寸法ＴBとは、互いに同程度（ＴF＝ＴB、０．２ｍｍ～０．４ｍｍ程度）となっている。なお、被溶接部１５ｂの厚み寸法ＴBと接続部１６の先端側の厚み寸法ＴFとは、０．８≦（ＴB／ＴF）≦１．２となるように設定されていることが好ましい。また、第一面１６ａと第二面１６ｂとの交差角度
θは、４０°以下であることが好ましい。 The shaft portion 13e has a connecting portion 16 that protrudes radially outward and is formed in a circumferentially continuous ring shape. As shown in FIG. 3B, the connecting portion 16 is formed in a protruding shape with a first surface 16a on the upper side along which the welded portion 15b is aligned, a second surface 16b on the opposite side (lower side), and a third surface 16c that constitutes the tip side of the connecting portion 16. The second surface 16b extends along a plane that is substantially perpendicular to the central axis X, and the intersection angle θ between the second surface 16b and the first surface 16a is about 30°. The thickness dimension TF of the tip side of the connecting portion 16 and the thickness dimension TB of the welded portion 15b are approximately the same (TF = TB, about 0.2 mm to 0.4 mm). It is preferable that the thickness dimension TB of the welded portion 15b and the thickness dimension TF of the tip side of the connecting portion 16 are set so that 0.8≦(TB/TF)≦1.2. In addition, the intersection angle θ between the first surface 16a and the second surface 16b is preferably 40° or less.

溶融固化部１７は、被溶接部１５ｂおよび接続部１６の先端側からの電子ビーム溶接によって被溶接部１５ｂおよび接続部１６の先端部を溶融、固化させることで形成され、周方向に連続した環状に形成されている。溶融固化部１７は、溶接時に溶融した金属が固化する際に、その表面張力によって収縮することで断面円形に形成されている。溶融固化部１７の中心Ｏは、被溶接部１５ｂと接続部１６の接触面（第一面１６ａ）の延長線上に位置し、溶融固化部１７の半径Ｒは、被溶接部１５ｂの厚み寸法ＴBおよび接続部１６の先
端側の厚み寸法ＴF以上であり、すなわち、溶融固化部１７の直径が被溶接部１５ｂおよ
び接続部１６の先端側を合せた厚み寸法以上に形成されている。なお、溶融固化部１７は、被溶接部１５ｂや接続部１６の先端にエッジが残らず、かつ滑らかに連続することが好ましく、そのために溶融固化部１７の直径は、被溶接部１５ｂおよび接続部１６の先端側を合せた厚み寸法の１．１倍以上かつ１．６倍以下であることが好ましい。 The melted and solidified portion 17 is formed by melting and solidifying the welded portion 15b and the tip of the connecting portion 16 by electron beam welding from the tip side of the welded portion 15b and the connecting portion 16, and is formed in a ring shape that is continuous in the circumferential direction. The melted and solidified portion 17 is formed in a circular cross section by shrinking due to the surface tension when the molten metal solidifies during welding. The center O of the melted and solidified portion 17 is located on an extension line of the contact surface (first surface 16a) of the welded portion 15b and the connecting portion 16, and the radius R of the melted and solidified portion 17 is equal to or larger than the thickness dimension TB of the welded portion 15b and the thickness dimension TF of the tip side of the connecting portion 16, that is, the diameter of the melted and solidified portion 17 is equal to or larger than the thickness dimension of the welded portion 15b and the tip side of the connecting portion 16 combined. It is preferable that the molten and solidified portion 17 is smooth and continuous without leaving any edges at the tips of the welded portion 15b and the connection portion 16, and therefore it is preferable that the diameter of the molten and solidified portion 17 is 1.1 to 1.6 times the combined thickness dimension of the welded portion 15b and the connection portion 16 at their tips.

次に、ダイヤフラム弁１０を構成する各部材の金属素材について説明する。金属ダイヤフラム１５は、主としてニッケル基合金から構成される。ニッケル基合金としては、耐熱性、耐蝕性、耐酸化性などに優れたインコネル（登録商標）が好適である。ニッケル基合金は、含有ニッケル量が５０％以上のものであって、ＮＣＦ６００、ＮＣＦ６０１、ＮＣＦ６２５、ＮＣＦ６９０、ＮＣＦ７１８、ＮＣＦ７５０、ＮＣＦ７５１、ＮＣＦ８０Ａ（以上の記号は、JIS G 4902:1992耐食耐熱超合金板に基づく）が例示できる。 Next, the metallic materials of each component that constitutes the diaphragm valve 10 will be described. The metallic diaphragm 15 is mainly composed of a nickel-based alloy. Inconel (registered trademark), which has excellent heat resistance, corrosion resistance, and oxidation resistance, is a suitable nickel-based alloy. The nickel-based alloy contains 50% or more nickel, and examples include NCF600, NCF601, NCF625, NCF690, NCF718, NCF750, NCF751, and NCF80A (the above symbols are based on JIS G 4902:1992 corrosion-resistant and heat-resistant superalloy plate).

弁体１３の連結部材１３ｃは、主としてオーステナイト系ステンレス鋼から構成される。オーステナイト系ステンレス鋼としては、ＳＵＳ３０４系のものが好適であるが、その中でも耐蝕性に優れたＳＵＳ３１６Ｌ、ＳＵＳ３１６ＬＮ、ＳＵＳ３２１、ＳＵＳ３４７が例示できる。このようなオーステナイト系ステンレス鋼からなる連結部材１３ｃと、ニッケル基合金からなる金属ダイヤフラム１５と、の溶接によって形成される溶融固化部１７は、主としてオーステナイト相となる。 The connecting member 13c of the valve body 13 is mainly made of austenitic stainless steel. SUS304-based austenitic stainless steel is suitable, but among them, SUS316L, SUS316LN, SUS321, and SUS347, which have excellent corrosion resistance, can be mentioned as examples. The molten and solidified portion 17 formed by welding the connecting member 13c made of such austenitic stainless steel to the metal diaphragm 15 made of a nickel-based alloy is mainly in the austenitic phase.

なお、本実施形態における溶接構造は、以下の図４に示すものであってもよい。図４は、ダイヤフラム弁１０における溶接構造の変形例を示す拡大断面図である。 The welding structure in this embodiment may be as shown in FIG. 4 below. FIG. 4 is an enlarged cross-sectional view showing a modified example of the welding structure in the diaphragm valve 10.

図４に示す変形例の溶接構造において、金属ダイヤフラム１５は、厚み寸法ｔが０．１ｍｍ～０．２ｍｍ程度の薄板材からなり、その被溶接部１５ｂは、薄板材の端部を折り返して重ねた折返部によって構成されている。この被溶接部１５ｂは、周方向に連続した環状に形成されるとともに、薄板材の端縁側が接続部１６の第一面１６ａに沿って設けられている。被溶接部１５ｂの厚み寸法ＴBは、薄板材を２枚重ねた寸法（ＴB＝２ｔ）であり、０．２ｍｍ～０．４ｍｍ程度となっている。また、接続部１６の第一面１６ａは、中心軸Ｘに対して略４５°傾斜した面に沿って延び、この第一面１６ａと第二面１６ｂとの交差角度θが１０°程度になっている。 In the modified welded structure shown in FIG. 4, the metal diaphragm 15 is made of a thin plate material with a thickness dimension t of about 0.1 mm to 0.2 mm, and the welded portion 15b is composed of a folded portion formed by folding back and overlapping the end of the thin plate material. The welded portion 15b is formed in a continuous ring shape in the circumferential direction, and the edge side of the thin plate material is provided along the first surface 16a of the connection portion 16. The thickness dimension TB of the welded portion 15b is the dimension of two overlapping thin plate materials (TB = 2t), and is about 0.2 mm to 0.4 mm. In addition, the first surface 16a of the connection portion 16 extends along a plane inclined at approximately 45° with respect to the central axis X, and the intersection angle θ between this first surface 16a and the second surface 16b is about 10°.

以上の本実施形態によれば、金属ダイヤフラム１５の被溶接部１５ｂおよび弁体１３の接続部１６の先端部に溶融固化部１７が設けられ、被溶接部１５ｂおよび接続部１６を合せた厚み寸法以上の直径を有する断面円形に溶融固化部１７が形成されている。このように被溶接部１５ｂおよび接続部１６の先端部同士を溶接することで、溶融した金属が表面張力で断面円形となり、凝固する過程で収縮したとしても、その収縮力が母材に作用しにくくなり、収縮による引張応力の発生を抑制することができる。従って、溶融固化部１７や周辺の母材における溶接割れを防止することができ、残留応力を抑制することによって溶接耐久性を向上させることができる。 According to the present embodiment described above, the melted and solidified portion 17 is provided at the tip of the welded portion 15b of the metal diaphragm 15 and the connection portion 16 of the valve body 13, and the melted and solidified portion 17 is formed into a circular cross section with a diameter equal to or greater than the combined thickness of the welded portion 15b and the connection portion 16. By welding the tips of the welded portion 15b and the connection portion 16 together in this way, the molten metal has a circular cross section due to surface tension, and even if it shrinks during the solidification process, the contraction force is less likely to act on the base material, and the generation of tensile stress due to shrinkage can be suppressed. Therefore, it is possible to prevent weld cracks in the melted and solidified portion 17 and the surrounding base material, and the welding durability can be improved by suppressing residual stress.

金属ダイヤフラム１５の被溶接部１５ｂの先端側および弁体１３の接続部１６の先端側
の厚み寸法ＴF，ＴBが互いに同程度であり、このように互いに同程度の厚み寸法を有した被溶接部１５ｂおよび接続部１６の先端部同士を溶接することで、溶接時の溶融金属量を同等にするとともに、生じる熱や応力を均等化することができ、母材に与える熱や応力の影響を抑制して溶接割れを防止することができる。 The thickness dimensions TF, TB of the tip side of the welded portion 15b of the metal diaphragm 15 and the tip side of the connection portion 16 of the valve body 13 are approximately the same, and by welding the tips of the welded portion 15b and the connection portion 16, which have approximately the same thickness dimensions, together, the amount of molten metal during welding can be made equivalent, and the generated heat and stress can be equalized. This makes it possible to suppress the effects of heat and stress on the base material and prevent weld cracks.

また、弁体１３の連結部材１３ｃが主としてオーステナイト系ステンレス鋼からなり、金属ダイヤフラム１５が主としてニッケル基合金からなり、溶融固化部１７が主としてオーステナイト相となる異種金属素材同士であり、溶融固化部１７や周辺の母材に溶接割れが生じやすい条件であっても、溶接割れを防止することができる。 In addition, the connecting member 13c of the valve body 13 is mainly made of austenitic stainless steel, the metal diaphragm 15 is mainly made of nickel-based alloy, and the molten solidified portion 17 is made of dissimilar metal materials that are mainly in the austenitic phase, so even under conditions where weld cracks are likely to occur in the molten solidified portion 17 and the surrounding base material, weld cracks can be prevented.

また、溶融固化部１７の直径が被溶接部１５ｂおよび接続部１６の先端側を合せた厚み寸法以上に形成されていることで、溶融固化部１７と被溶接部１５ｂおよび接続部１６とを滑らかに連続させ、被溶接部１５ｂや接続部１６の先端にエッジが残らないようにでき、溶接部の溶接耐久性や力学特性を向上させることができる。 In addition, by forming the diameter of the molten solidified portion 17 to be equal to or greater than the combined thickness of the tip side of the welded portion 15b and the connection portion 16, the molten solidified portion 17 is smoothly connected to the welded portion 15b and the connection portion 16, and no edges remain at the tips of the welded portion 15b and the connection portion 16, improving the welding durability and mechanical properties of the welded portion.

また、接続部１６における第一面１６ａと第二面１６ｂとが先端に向かって狭まる４０°以下の交差角度θで設けられていることで、溶融金属が凝固する際の収縮力が母材に与える影響を抑制し、接続部１６周辺の溶接割れを防止することができる。 In addition, the first surface 16a and the second surface 16b of the connection portion 16 are arranged at an intersection angle θ of 40° or less, narrowing toward the tip, which suppresses the effect on the base material of the contraction force caused when the molten metal solidifies, and prevents weld cracks around the connection portion 16.

また、金属ダイヤフラム１５において、図４に示すように、薄板材の端部を折り返して重ねた折返部によって被溶接部１５ｂを構成することで、被溶接部１５ｂの厚み寸法が大きくなり、溶接時の熱の影響や凝固する際の収縮力の影響を抑制し、被溶接部１５ｂの溶接割れを防止することができる。 In addition, in the metal diaphragm 15, as shown in FIG. 4, the welded portion 15b is formed by folding back the end of the thin plate material, which increases the thickness of the welded portion 15b, suppressing the effects of heat during welding and the effects of contraction forces during solidification, and preventing weld cracks in the welded portion 15b.

また、ダイヤフラム弁１０の金属ダイヤフラム１５において、周方向に連続した溶融固化部１７が形成され、この溶融固化部１７周辺の溶接割れが防止されて溶接耐久性が向上することで、金属ダイヤフラム１５の良好なシール性が維持されることからダイヤフラム弁１０の製品寿命を延ばすことができる。 In addition, a continuous molten solidified portion 17 is formed in the metal diaphragm 15 of the diaphragm valve 10 in the circumferential direction, and weld cracks are prevented around this molten solidified portion 17, improving the weld durability. This maintains good sealing properties of the metal diaphragm 15, thereby extending the product life of the diaphragm valve 10.

次に、本発明の第２実施形態に係る溶接構造を用いた弁装置について、図５～図７を参照して説明する。図５は、本実施形態の弁装置であるダイヤフラム弁２０を示す断面図である。図６は、ダイヤフラム弁２０の要部を示す拡大断面図であり、図５に丸囲み部Ａで示す部分の拡大図である。図７は、ダイヤフラム弁２０における溶接構造を示す拡大断面図であり、図６に丸囲み部Ｂで示す部分の拡大図である。また、図７（Ａ）は溶接接合された弁体およびダイヤフラムの要部を示し、図７（Ｂ）は弁体およびダイヤフラムの溶接接合前の状態を示している。 Next, a valve device using a welded structure according to a second embodiment of the present invention will be described with reference to Figs. 5 to 7. Fig. 5 is a cross-sectional view showing a diaphragm valve 20, which is the valve device of this embodiment. Fig. 6 is an enlarged cross-sectional view showing the main parts of the diaphragm valve 20, and is an enlarged view of the part circled A in Fig. 5. Fig. 7 is an enlarged cross-sectional view showing the welded structure of the diaphragm valve 20, and is an enlarged view of the part circled B in Fig. 6. Fig. 7(A) shows the main parts of the valve body and diaphragm that have been welded together, and Fig. 7(B) shows the state of the valve body and diaphragm before they are welded together.

ダイヤフラム弁２０は、前記第１実施形態のダイヤフラム弁１０と略同様の構造を備えた手動開閉タイプのバルブであり、図５に示すように、内部に弁室２１を有する弁本体（ボディ）２２と、弁室２１内に設けられた弁体２３と、弁体２３を進退移動させるために回転操作される操作部２４と、弁室２１の内部をシールする金属ダイヤフラム２５と、を備える。弁本体２２は、互いに螺合される第１部材２２ａおよび第２部材２２ｂを備え、第１部材２２ａと第２部材２２ｂとの面合せ部に金属ダイヤフラム２５の外周縁が挟持されている。 The diaphragm valve 20 is a manually opened/closed type valve having a structure substantially similar to that of the diaphragm valve 10 of the first embodiment, and as shown in FIG. 5, comprises a valve body 22 having a valve chamber 21 therein, a valve element 23 provided in the valve chamber 21, an operating part 24 which is rotated to move the valve element 23 back and forth, and a metal diaphragm 25 which seals the inside of the valve chamber 21. The valve body 22 comprises a first member 22a and a second member 22b which are screwed together, and the outer periphery of the metal diaphragm 25 is clamped at the face-to-face portion of the first member 22a and the second member 22b.

弁本体２２の第１部材２２ａは、流入ポート２２ｃと、流出ポート２２ｄと、弁ポート２２ｅと、を備え、第２部材２２ｂは、軸受部２２ｆと、雌ねじ部２２ｇと、を備えて構成されている。弁体２３は、図６に示すように、弁体ケース２３ａと、弁部材２３ｂと、連結部材２３ｃと、球体２３ｄと、を有して構成されている。連結部材２３ｃは、円柱状の軸部２３ｅを有し、この軸部２３ｅに金属ダイヤフラム２５が固定されている。操作部
２４は、ハンドル２４ａと、軸部２４ｂと、雄ねじ部２４ｃと、当接部２４ｄと、を備える。 The first member 22a of the valve body 22 includes an inlet port 22c, an outlet port 22d, and a valve port 22e, and the second member 22b includes a bearing portion 22f and a female thread portion 22g. As shown in Fig. 6, the valve body 23 includes a valve body case 23a, a valve member 23b, a connecting member 23c, and a ball 23d. The connecting member 23c includes a cylindrical shaft portion 23e, and a metal diaphragm 25 is fixed to the shaft portion 23e. The operating portion 24 includes a handle 24a, a shaft portion 24b, a male thread portion 24c, and a contact portion 24d.

金属ダイヤフラム２５は、１枚の全体円形板状（皿状）の金属薄板材からなり、中央部に弁体２３の軸部２３ｅを挿通させる挿通孔２５ａが形成されている。金属ダイヤフラム２５は、その外周縁が弁本体２２の第１部材２２ａと第２部材２２ｂとの間に挟持され、挿通孔２５ａの内周縁が弁体２３の軸部２３ｅに溶接固定されている。 The metal diaphragm 25 is made of a single circular (dish-shaped) thin metal plate, and has a through hole 25a formed in the center for inserting the shaft portion 23e of the valve body 23. The outer peripheral edge of the metal diaphragm 25 is sandwiched between the first member 22a and the second member 22b of the valve body 22, and the inner peripheral edge of the through hole 25a is welded and fixed to the shaft portion 23e of the valve body 23.

次に、図７を参照して金属ダイヤフラム２５と弁体２３の軸部２３ｅとの溶接構造について説明する。金属ダイヤフラム２５の厚み寸法ｔは、０．２ｍｍ～０．４ｍｍ程度であり、挿通孔２５ａ側の端部には、軸方向（中心軸Ｘの方向）に沿って上方に折り曲げられるとともに、周方向に連続した環状の被溶接部２５ｂが設けられている。被溶接部２５ｂの厚み寸法ＴBは、金属ダイヤフラム２５の厚み寸法ｔと略同一（ＴB＝ｔ）の０．２ｍｍ～０．４ｍｍ程度となっている。 Next, the welded structure between the metal diaphragm 25 and the shaft portion 23e of the valve body 23 will be described with reference to Figure 7. The thickness dimension t of the metal diaphragm 25 is approximately 0.2 mm to 0.4 mm, and the end on the insertion hole 25a side is bent upward along the axial direction (the direction of the central axis X) and has a ring-shaped welded portion 25b that is continuous in the circumferential direction. The thickness dimension TB of the welded portion 25b is approximately 0.2 mm to 0.4 mm, which is approximately the same as the thickness dimension t of the metal diaphragm 25 (TB = t).

軸部２３ｅには、軸方向に沿って上方に突出した接続部２６が周方向に連続した環状に形成されている。接続部２６は、図７（Ｂ）に示すように、被溶接部２５ｂが沿う径方向外側の第一面２６ａと、その反対側（径方向内側）の第二面２６ｂと、接続部２６の先端側を構成する第三面２６ｃと、を有して突起状に形成され、第一面２６ａと第二面２６ｂとの交差角度θが２０°程度になっている。接続部２６の先端側の厚み寸法ＴFと、被溶
接部２５ｂの厚み寸法ＴBとは、互いに同程度（ＴF＝ＴB、０．２ｍｍ～０．４ｍｍ程度
）となっている。なお、被溶接部２５ｂの厚み寸法ＴBと接続部２６の先端側の厚み寸法
ＴFとは、０．８≦（ＴB／ＴF）≦１．２となるように設定されていることが好ましい。
また、第一面２６ａと第二面２６ｂとの交差角度θは、４０°以下であることが好ましい。 The shaft portion 23e has a connecting portion 26 that protrudes upward along the axial direction and is formed in a ring shape that is continuous in the circumferential direction. As shown in FIG. 7B, the connecting portion 26 is formed in a protruding shape having a first surface 26a on the radially outer side along which the welded portion 25b is aligned, a second surface 26b on the opposite side (radially inner side), and a third surface 26c that constitutes the tip side of the connecting portion 26, and the intersection angle θ between the first surface 26a and the second surface 26b is about 20°. The thickness dimension TF of the tip side of the connecting portion 26 and the thickness dimension TB of the welded portion 25b are approximately the same (TF = TB, about 0.2 mm to 0.4 mm). It is preferable that the thickness dimension TB of the welded portion 25b and the thickness dimension TF of the tip side of the connecting portion 26 are set to be 0.8≦(TB/TF)≦1.2.
In addition, the intersection angle θ between the first surface 26a and the second surface 26b is preferably 40° or less.

溶融固化部２７は、被溶接部２５ｂおよび接続部２６の先端側からの電子ビーム溶接によって被溶接部２５ｂおよび接続部２６の先端部を溶融、固化させることで形成され、周方向に連続した環状に形成されている。溶融固化部２７は、溶接時に溶融した金属が固化する際に、その表面張力によって収縮することで断面円形に形成されている。溶融固化部２７の中心Ｏは、被溶接部２５ｂと接続部２６の接触面（第一面２６ａ）の延長線上に位置し、溶融固化部２７の半径Ｒは、被溶接部２５ｂの厚み寸法ＴBおよび接続部２６の先
端側の厚み寸法ＴF以上であり、すなわち、溶融固化部２７の直径が被溶接部２５ｂおよ
び接続部２６の先端側を合せた厚み寸法以上に形成されている。なお、溶融固化部２７は、被溶接部２５ｂや接続部２６の先端にエッジが残らず、かつ滑らかに連続することが好ましく、そのために溶融固化部２７の直径は、被溶接部２５ｂおよび接続部２６の先端側を合せた厚み寸法の１．１倍以上かつ１．６倍以下であることが好ましい。 The melted and solidified portion 27 is formed by melting and solidifying the welded portion 25b and the tip of the connecting portion 26 by electron beam welding from the tip side of the welded portion 25b and the connecting portion 26, and is formed in a ring shape that is continuous in the circumferential direction. The melted and solidified portion 27 is formed in a circular cross section by shrinking due to the surface tension when the molten metal solidifies during welding. The center O of the melted and solidified portion 27 is located on an extension line of the contact surface (first surface 26a) of the welded portion 25b and the connecting portion 26, and the radius R of the melted and solidified portion 27 is equal to or larger than the thickness dimension TB of the welded portion 25b and the thickness dimension TF of the tip side of the connecting portion 26, that is, the diameter of the melted and solidified portion 27 is equal to or larger than the combined thickness dimension of the welded portion 25b and the tip side of the connecting portion 26. It is preferable that the molten and solidified portion 27 be smooth and continuous without leaving any edges at the tips of the welded portion 25b and the connection portion 26, and therefore it is preferable that the diameter of the molten and solidified portion 27 be 1.1 to 1.6 times the combined thickness dimension of the welded portion 25b and the connection portion 26 at their tips.

以上のダイヤフラム弁２０を構成する各部材の金属素材としては、前記第１実施形態のダイヤフラム弁１０と同様であり、金属ダイヤフラム２５は、主としてニッケル基合金から構成され、弁体２３の連結部材２３ｃは、主としてオーステナイト系ステンレス鋼から構成される。従って、連結部材２３ｃと金属ダイヤフラム２５との溶接によって形成される溶融固化部２７は、主としてオーステナイト相となる。なお、本実施形態において、被溶接部２５ｂは、金属ダイヤフラム２５の挿通孔２５ａ側の端部から軸方向下向きに折り曲げられ、接続部２６は、軸部２３ｅから軸方向に下向きに突出して設けられ、これらの被溶接部２５ｂと接続部２６の先端部同士が溶接接合されていてもよい。 The metal materials of the components constituting the diaphragm valve 20 are the same as those of the diaphragm valve 10 of the first embodiment, the metal diaphragm 25 being mainly made of a nickel-based alloy, and the connecting member 23c of the valve body 23 being mainly made of austenitic stainless steel. Therefore, the molten solidified portion 27 formed by welding the connecting member 23c and the metal diaphragm 25 is mainly in the austenitic phase. In this embodiment, the welded portion 25b is bent axially downward from the end of the metal diaphragm 25 on the insertion hole 25a side, and the connecting portion 26 is provided so as to protrude axially downward from the shaft portion 23e, and the tips of the welded portion 25b and the connecting portion 26 may be welded together.

以上の本実施形態によれば、前記第１実施形態と同様の効果を奏することができ、溶融固化部２７や周辺の母材における溶接割れを防止することができ、残留応力を抑制することによって溶接耐久性を向上させることができる。従って、金属ダイヤフラム２５の良好
なシール性が維持されることからダイヤフラム弁２０の製品寿命を延ばすことができる。 According to the present embodiment described above, the same effects as those of the first embodiment can be obtained, and weld cracks in the molten solidified portion 27 and the surrounding base material can be prevented, and the welding durability can be improved by suppressing residual stress. Therefore, good sealing performance of the metal diaphragm 25 can be maintained, and the product life of the diaphragm valve 20 can be extended.

なお、本発明は、前記実施形態に限定されるものではなく、本発明の目的が達成できる他の構成等を含み、以下に示すような変形等も本発明に含まれる。例えば、前記実施形態では、弁装置として、手動開閉タイプのバルブを例示したが、本発明の弁装置は、モータによって駆動される電動弁や、その他の開閉形式を備えたものなどにも適用可能である。 The present invention is not limited to the above-described embodiment, but includes other configurations that can achieve the object of the present invention, and the following modifications are also included in the present invention. For example, in the above-described embodiment, a manually opened and closed valve is exemplified as the valve device, but the valve device of the present invention can also be applied to an electrically operated valve driven by a motor, or to valves with other opening and closing methods.

また、前記実施形態では、弁体１３，２３の軸部１３ｅ，２３ｅおよび金属ダイヤフラム１５，２５の金属素材として、オーステナイト系ステンレス鋼とニッケル基合金との組合せを例示したが、各部の金属素材としては、同種のものを組み合わせてもよいし、前記実施形態の組合せ以外の異種金属を組み合わせてもよい。また、金属ダイヤフラム１５，２５の被溶接部１５ｂ，２５ｂおよび弁体１３，２３の接続部１６，２６の形状や寸法についても前記実施形態のものに限定されず、それらの先端部に形成される溶融固化部が断面円形となっていればよい。 In addition, in the above embodiment, a combination of austenitic stainless steel and nickel-based alloy was exemplified as the metal material of the shaft portion 13e, 23e of the valve body 13, 23 and the metal diaphragm 15, 25, but the metal materials of each part may be a combination of the same type, or a combination of different metals other than those in the above embodiment. In addition, the shapes and dimensions of the welded parts 15b, 25b of the metal diaphragm 15, 25 and the connection parts 16, 26 of the valve body 13, 23 are not limited to those in the above embodiment, and it is sufficient that the molten and solidified parts formed at their tips have a circular cross section.

また、前記実施形態では、被溶接部１５ｂ，２５ｂおよび接続部１６，２６の先端部を電子ビーム溶接によって溶接して溶融固化部１７が形成されるものとしたが、これに限らず、レーザー溶接やマイクロプラズマ溶接（ＴＩＧ溶接）など、適宜な溶接方法を採用することができる。 In addition, in the above embodiment, the molten and solidified portion 17 is formed by welding the tips of the welded portions 15b, 25b and the connecting portions 16, 26 by electron beam welding, but this is not limited to the above, and any suitable welding method such as laser welding or microplasma welding (TIG welding) can be used.

また、前記第２実施形態では、金属ダイヤフラム２５の挿通孔２５ａ側の端部に、軸方向に沿って上方に折り曲げられた被溶接部２５ｂが設けられるものとしたが、ダイヤフラムは、挿通孔側において軸方向に沿って折り曲げられた後、径方向に沿って折り曲げられていてもよい。 In addition, in the second embodiment, the end of the metal diaphragm 25 on the insertion hole 25a side is provided with a welded portion 25b bent upward along the axial direction, but the diaphragm may be bent along the radial direction after being bent along the axial direction on the insertion hole side.

例えば、第１の変形例として図８に示す溶接構造のように、金属ダイヤフラム３が、接続部２６の第一面２６ａに沿って軸方向に延びる第１環状部３１と、第１環状部３１の先端から径方向の内側方向に延びる第２環状部３２と、を有する構成としてもよい。第１環状部３１は、前記第２実施形態の被溶接部２５ｂに相当する部分であって、周方向に連続して形成される。第２環状部３２は、周方向に連続して形成され、接続部２６の先端部である第三面２６ｃに重ねられる。電子ビーム溶接によって、第２環状部３２および接続部２６の先端部を溶融、固化させることにより、周方向に連続した環状の溶融固化部３３が形成される。このとき、第１環状部３１の先端部も同時に溶融、固化されてもよい。また、図示の形状では、第２環状部３２全体が溶融されているが、第２環状部３２のうち先端部のみが溶融されてもよい。 For example, as a first modified example, as shown in FIG. 8, the metal diaphragm 3 may have a first annular portion 31 extending in the axial direction along the first surface 26a of the connection portion 26, and a second annular portion 32 extending in the radially inward direction from the tip of the first annular portion 31. The first annular portion 31 corresponds to the welded portion 25b in the second embodiment, and is formed continuously in the circumferential direction. The second annular portion 32 is formed continuously in the circumferential direction and is overlapped on the third surface 26c, which is the tip of the connection portion 26. The second annular portion 32 and the tip of the connection portion 26 are melted and solidified by electron beam welding to form a circumferentially continuous ring-shaped melted and solidified portion 33. At this time, the tip of the first annular portion 31 may also be melted and solidified at the same time. In the illustrated shape, the entire second annular portion 32 is melted, but only the tip of the second annular portion 32 may be melted.

尚、第１の変形例では、前記第２実施形態と同様に接続部２６が軸方向に沿って突出しているものとしたが、前記第１実施形態のように接続部１６が径方向に沿って突出した構成において、ダイヤフラムに、接続部１６の第一面１６ａに沿って径方向の外側方向に延びるとともに周方向に連続した第１環状部と、第１環状部の先端から軸方向に延びて接続部１６の先端部に重ねられるとともに周方向に連続した第２環状部と、を設けてもよい。 In the first modified example, the connection portion 26 protrudes along the axial direction as in the second embodiment. However, in a configuration in which the connection portion 16 protrudes along the radial direction as in the first embodiment, the diaphragm may be provided with a first annular portion that extends radially outward along the first surface 16a of the connection portion 16 and is continuous in the circumferential direction, and a second annular portion that extends axially from the tip of the first annular portion, overlaps the tip of the connection portion 16, and is continuous in the circumferential direction.

また、前記実施形態では、金属ダイヤフラム１５、２５が１枚の金属薄板材からなるものとしたが、ダイヤフラムは複数の薄板材によって構成されていてもよい。例えば第２～第４の変形例として図９～１１のそれぞれに示す溶接構造のように、金属ダイヤフラムが２枚の金属薄板材によって構成されるものとしてもよい。 In addition, in the above embodiment, the metal diaphragms 15, 25 are made of a single sheet of metal material, but the diaphragms may be made of multiple sheets of metal material. For example, the metal diaphragms may be made of two sheets of metal material, as in the welded structures shown in Figures 9 to 11 as second to fourth modified examples.

第２の変形例の溶接構造では、金属ダイヤフラム４が、上側の第１薄板４１と下側の第２薄板４２とを有する。第１薄板４１は、接続部２６の第一面２６ａに沿って軸方向に延びる第１環状部４１１と、第１環状部４１１の先端から径方向の内側方向に延びる第２環
状部４１２と、を有し、第１の変形例における金属ダイヤフラム３と同様の形状を有している。第２薄板４２は、接続部２６の第一面２６ａに沿って軸方向に延びる被溶接部４２１を有し、前記第２実施形態の金属ダイヤフラム２５と同様の形状を有している。電子ビーム溶接によって、第２環状部４１２の先端部と、被溶接部４２１の先端部と、接続部２６の先端部と、を溶融、固化させることにより、周方向に連続した環状の溶融固化部４３が形成される。このとき、第１環状部４１１の先端部も同時に溶融、固化されてもよい。 In the welded structure of the second modification, the metal diaphragm 4 has a first thin plate 41 on the upper side and a second thin plate 42 on the lower side. The first thin plate 41 has a first annular portion 411 extending in the axial direction along the first surface 26a of the connecting portion 26, and a second annular portion 412 extending in the radially inward direction from the tip of the first annular portion 411, and has a shape similar to that of the metal diaphragm 3 in the first modification. The second thin plate 42 has a welded portion 421 extending in the axial direction along the first surface 26a of the connecting portion 26, and has a shape similar to that of the metal diaphragm 25 of the second embodiment. The tip of the second annular portion 412, the tip of the welded portion 421, and the tip of the connecting portion 26 are melted and solidified by electron beam welding to form a ring-shaped melted and solidified portion 43 that is continuous in the circumferential direction. At this time, the tip of the first annular portion 411 may also be melted and solidified at the same time.

第３の変形例の溶接構造では、金属ダイヤフラム５が、上側の第１薄板５１と下側の第２薄板５２とを有する。第１薄板５１は、接続部２６の第一面２６ａに沿って軸方向に延びる第１環状部５１１と、第１環状部５１１の先端から径方向の内側方向に延びる第２環状部５１２と、を有し、第１の変形例における金属ダイヤフラム３と同様の形状を有している。第２薄板５２は、接続部２６の第一面２６ａに沿って軸方向に延びる第１環状部５２１と、第１環状部５２１の先端から径方向の内側方向に延びる第２環状部５２２と、を有し、第１の変形例における金属ダイヤフラム３と同様の形状を有している。電子ビーム溶接によって、第２環状部５１２の先端部と、第２環状部５２２の先端部と、接続部２６の先端部と、を溶融、固化させることにより、周方向に連続した環状の溶融固化部５３が形成される。このとき、第１環状部５１１、５２１の先端部も同時に溶融、固化されてもよい。 In the welding structure of the third modified example, the metal diaphragm 5 has a first thin plate 51 on the upper side and a second thin plate 52 on the lower side. The first thin plate 51 has a first annular portion 511 extending in the axial direction along the first surface 26a of the connection portion 26, and a second annular portion 512 extending in the radially inward direction from the tip of the first annular portion 511, and has a shape similar to that of the metal diaphragm 3 in the first modified example. The second thin plate 52 has a first annular portion 521 extending in the axial direction along the first surface 26a of the connection portion 26, and a second annular portion 522 extending in the radially inward direction from the tip of the first annular portion 521, and has a shape similar to that of the metal diaphragm 3 in the first modified example. The tip of the second annular portion 512, the tip of the second annular portion 522, and the tip of the connection portion 26 are melted and solidified by electron beam welding to form a ring-shaped melted and solidified portion 53 that is continuous in the circumferential direction. At this time, the tips of the first annular portions 511 and 521 may also be melted and solidified at the same time.

第４の変形例の溶接構造では、金属ダイヤフラム６が、上側の第１薄板６１と下側の第２薄板６２とを有する。第１薄板６１は、接続部２６の第一面２６ａに沿って軸方向に延びる被溶接部６１１を有し、前記第２実施形態の金属ダイヤフラム２５と同様の形状を有している。第２薄板６２は、接続部２６の第一面２６ａに沿って軸方向に延びる被溶接部６２１を有し、前記第２実施形態の金属ダイヤフラム２５と同様の形状を有している。電子ビーム溶接によって、被溶接部６１１の先端部と、被溶接部６２１の先端部と、接続部２６の先端部と、を溶融、固化させることにより、周方向に連続した環状の溶融固化部６３が形成される。 In the welded structure of the fourth modified example, the metal diaphragm 6 has a first thin plate 61 on the upper side and a second thin plate 62 on the lower side. The first thin plate 61 has a welded portion 611 extending in the axial direction along the first surface 26a of the connection portion 26, and has a shape similar to that of the metal diaphragm 25 of the second embodiment. The second thin plate 62 has a welded portion 621 extending in the axial direction along the first surface 26a of the connection portion 26, and has a shape similar to that of the metal diaphragm 25 of the second embodiment. The tip of the welded portion 611, the tip of the welded portion 621, and the tip of the connection portion 26 are melted and solidified by electron beam welding to form a ring-shaped melted and solidified portion 63 that is continuous in the circumferential direction.

尚、第２～第４の変形例においては、第１薄板および第２薄板の合計の厚み寸法は、前記実施形態における金属ダイヤフラム１５、２５の厚み方向寸法ｔと同程度であればよい。また、第１～第４の変形例の溶融固化部３３、４３、５３、６３は、前記実施形態における溶融固化部１７、２７と同程度の寸法を有していればよい。 In the second to fourth modified examples, the total thickness dimension of the first and second thin plates need only be approximately the same as the thickness dimension t of the metal diaphragms 15 and 25 in the above embodiment. Also, the melt-solidified portions 33, 43, 53, and 63 in the first to fourth modified examples need only have approximately the same dimensions as the melt-solidified portions 17 and 27 in the above embodiment.

以上、本発明の実施の形態について図面を参照して詳述してきたが、具体的な構成はこれらの実施の形態に限られるものではなく、本発明の要旨を逸脱しない範囲の設計の変更等があっても本発明に含まれる。 The above describes the embodiments of the present invention in detail with reference to the drawings, but the specific configuration is not limited to these embodiments, and the present invention also includes design changes that do not deviate from the gist of the present invention.

１０，２０ダイヤフラム弁（弁装置）
１１，２１弁室
１３，２３弁体
１３ｅ，２３ｅ軸部
１５，２５、３～６金属ダイヤフラム
１５ａ，２５ａ挿通孔
１５ｂ，２５ｂ、４２１、６１１、６２１被溶接部
１６，２６接続部
１６ａ，２６ａ第一面
１６ｂ，２６ｂ第二面
１７，２７、３３、４３、５３、６３溶融固化部
３１、４１１、５１１、５２１第１環状部
３２、４１２、５１２、５２２第２環状部 10, 20 Diaphragm valve (valve device)
11, 21 Valve chamber 13, 23 Valve body 13e, 23e Shaft portion 15, 25, 3 to 6 Metal diaphragm 15a, 25a Insertion hole 15b, 25b, 421, 611, 621 Welded portion 16, 26 Connection portion 16a, 26a First surface 16b, 26b Second surface 17, 27, 33, 43, 53, 63 Melted and solidified portion 31, 411, 511, 521 First annular portion 32, 412, 512, 522 Second annular portion

Claims

A welding structure for welding and joining a valve body and a diaphragm in a valve device including a valve body provided in a valve chamber and a diaphragm that seals the valve chamber, comprising:
The valve body has a cylindrical shaft portion,
The diaphragm is made of one or more thin plate materials and has an insertion hole through which the shaft portion is inserted,
The shaft portion is provided with an annular connection portion that has a first surface and a second surface opposite thereto, protrudes in the axial direction, and is continuous in the circumferential direction;
The insertion hole of the diaphragm is provided with an annular welded portion that extends in an axial direction along the first surface of the connection portion and is continuous in a circumferential direction,
A welded structure characterized in that the connecting portion and the welded portion have their respective tip portions welded to each other and joined by a molten and solidified portion having a circular cross section.

The welded structure described in claim 1, characterized in that the welded portion is formed by folding back and overlapping an end of a thin plate material that constitutes the diaphragm, and the end edge side of the thin plate material is provided along the first surface of the connection portion.

The welded structure according to claim 1 or 2, characterized in that the diameter of the molten and solidified portion is equal to or greater than the combined thickness of the tip side of the connection portion and the welded portion.

The welded structure according to any one of claims 1 to 3, characterized in that the thickness dimensions of the tip side of the connection part and the tip side of the welded part are approximately the same.

The welded structure described in any one of claims 1 to 4, characterized in that the stem of the valve body is mainly made of austenitic stainless steel, and the thin plate material of the diaphragm is mainly made of a nickel-based alloy.

The welded structure according to any one of claims 1 to 5, characterized in that the diameter of the molten solidified portion is 1.1 times or more and 1.6 times or less than the combined thickness dimension of the tip side of the connection portion and the welded portion.

The welded structure according to any one of claims 1 to 6, characterized in that the first surface and the second surface at the connection portion are provided at an intersection angle that narrows toward a tip of the connection portion, and the intersection angle is 40° or less.