Electromagnetic valve and manufacturing method thereof

Abstract

To provide an electromagnetic valve having a fixed structure of a case, an attraction element, and a holder suitable for reducing costs.SOLUTION: An electromagnetic valve 1 includes: a main valve element 40 for opening / closing a main valve port 15 in a valve body 10; a connection body 20 for integrally fixing a case 32 in which a plunger 33 is arranged inside and an electromagnetic coil 34 is mounted outside, a holder 21 connected to the valve body 10, and an attraction element 25 for attracting the plunger 33; and a pilot valve element 36 connected to the plunger 33 through a valve shaft 35 for opening / closing a pilot valve port 45 in the main valve element 40. In the connection body 20, the connection part of the holder 21 and the attraction element 25, and the connection part of the attraction element 25 and the case 32 are both brazed.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a solenoid valve and a method for manufacturing the same.

Background Art

[0002] Solenoid valves include a normally closed type (normally closed) that opens only when energized and a normally open type (normally open) that closes only when energized. Solenoid valves also include a direct-acting type that directly opens and closes a valve body by an electromagnetic coil and a pilot type that opens and closes a pilot valve by an electromagnetic coil and opens and closes a main valve in response to the opening and closing of the pilot valve. These solenoid valves are properly selected according to the intended use. The following patent documents disclose solenoid valves.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the solenoid valve described in Patent Document 1, a screw portion is integrally formed on the armature in order to screw the armature to the valve body. Since the armature is formed by machining a soft magnetic metal workpiece, such an armature has a large amount of machining waste of the workpiece, and there is a risk of increasing material costs and processing costs. In addition, since the armature is exposed to the atmosphere outside the case, the requirement for corrosion resistance of the armature has also made it difficult to reduce costs.

[0005] The solenoid valve described in Patent Document 2 processes a holder having a threaded portion screwed onto a valve body and an armature as separate members, and reduces the machining allowance of the workpiece by integrating the holder and the armature after machining. Further, by welding a case to the holder and arranging the armature inside the case, the armature can be manufactured from a material with low corrosion resistance.

[0006] However, since the case is welded to the holder, the shape of the holder has become complicated so that the torch (coupler part) of the welding machine does not buffer during welding. For this reason, further improvements have been desired in reducing the man-hours and material costs when machining the screw member.

[0007] An object of the present invention is to provide a solenoid valve and a method for manufacturing the same that can improve workability during solenoid valve manufacturing and contribute to cost reduction of the solenoid valve by using a fixing structure for a case, an armature, and a holder that can solve the above problems.

Means for Solving the Problems

[0008] In order to achieve the above object, the solenoid valve of the present invention includes a valve body having a valve port, a case in which a plunger is arranged inside and an electromagnetic coil is mounted outside, a holder connected to the valve body, and a connection body in which an armature that attracts the plunger is integrally fixed, and a valve body connected to the plunger via a valve shaft and opening and closing the valve port. The connection body has brazing at the connection portion between the holder and the armature and at the connection portion between the armature and the case.

[0009] Alternatively, in order to achieve the above object, the solenoid valve of the present invention includes a valve body, a main valve body that opens and closes a main valve port in the valve body, a case in which a plunger is arranged inside and an electromagnetic coil is mounted outside, a holder connected to the valve body, and a connection body in which an armature that attracts the plunger is integrally fixed, and a pilot valve body connected to the plunger via a valve shaft and opening and closing a pilot valve port in the main valve body. The connection body has brazing at the connection portion between the holder and the armature and at the connection portion between the armature and the case.

[0010] To achieve the above object, a method for manufacturing a solenoid valve according to the present invention includes a valve body having a valve port, a case in which a plunger is disposed inside and an electromagnetic coil is attached outside, a holder connected to the valve body, and a connecting body in which an attractor for attracting the plunger is integrally fixed, and a valve body connected to the plunger via a valve shaft and opening and closing the valve port. The method for manufacturing a solenoid valve includes a brazing step of manufacturing the connecting body by simultaneously brazing the holder and the attractor and brazing the attractor and the case.

[0011] Alternatively, to achieve the above object, a method for manufacturing a solenoid valve according to the present invention includes a valve body, a main valve body that opens and closes a main valve port in the valve body, a case in which a plunger is disposed inside and an electromagnetic coil is attached outside, a holder connected to the valve body, a connecting body in which an attractor for attracting the plunger is integrally fixed, and a pilot valve body connected to the plunger via a valve shaft and opening and closing a pilot valve port in the main valve body. The method for manufacturing a solenoid valve includes a brazing step of manufacturing the connecting body by simultaneously brazing the holder and the attractor and brazing the attractor and the case.

Advantages of the Invention

[0012] By using the fixing structure of the case, the attractor, and the holder part according to the present invention, it is possible to provide a solenoid valve that can reduce the processing man-hours and material costs during solenoid valve manufacturing and improve workability.

[0013] Other objects, features, and advantages of the present invention will be clarified by the following description of the embodiments of the present invention based on the drawings. In each figure, the same reference numerals indicate the same or corresponding parts.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Best Mode for Carrying Out the Invention

[0015] Hereinafter, a pilot-type solenoid valve according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

[0016] FIG. 1 is a cross-sectional view of the solenoid valve in the valve-open state according to an embodiment of the present invention. FIG. 2 is an explanatory view of the connector, which is shown as a cross-sectional view in accordance with FIG. 1. In the following description, the terms "up and down, left and right" indicate the relative positional relationship of the components shown in each figure.

[0017] As shown in FIG. 1, the solenoid valve 1 according to the present embodiment includes a valve body 10, a connector 20, a plunger 33, an electromagnetic coil 34, a valve shaft 35, a pilot valve body 36, and a main valve body 40. Here, the connector 20 is a sub-assembly in which an armature 25, a holder 21 having a threaded portion formed thereon, and a case 32 are integrally fixed. The electromagnetic coil 34 includes a coil 34a and a housing 34b, and is mounted on the outer peripheral portion of the case 32.

[0018] The valve body 10 has a substantially cylindrical shape. The valve body 10 includes an inlet 11, an outlet 12, a main valve chamber 14, a main valve port 15, and a main valve seat 16. The valve body 10 is made of, for example, an aluminum alloy. Further, a thread 10a is formed on the outer peripheral portion of the valve body 10. The solenoid valve 1 of the present embodiment is mounted and used on a housing (flow path block) (not shown) by the thread 10a. When the valve body 10 is inserted into the valve mounting hole of the housing, the outlet 12 on the bottom surface of the valve body 10 communicates with the outflow passage opened on the bottom surface of the valve mounting hole of the housing, whereby the refrigerant in the main valve chamber 14 can be made to flow out through the outflow passage.

[0019] On the one hand, the valve body 10 is provided with a plurality of (in this embodiment, a total of four, one each on the front, rear, left, and right) openings on its circumferential surface that can be used as flow paths for the refrigerant flowing into the valve chamber 14, and these openings serve as the above-mentioned inlet 11. When the valve body 10 is inserted into the valve mounting hole of the housing, the four openings (inlets 11) of the valve body 10 communicate with the inlet passage on the housing side. As a result, it becomes possible to allow the refrigerant to flow into the main valve chamber 14 through these openings.

[0020] In addition, the seal between the outside and the inlet passage side and the outlet passage side is achieved by the seal members (O-rings) 33 and 34 respectively mounted on the two groove portions formed on the outer peripheral surface of the valve body 13.

[0021] The holder 21 is coupled to the mounting portion 17 of the valve body 10. A male thread is formed on the outer peripheral surface of the holder 21, and a female thread is formed on the inner peripheral surface of the mounting portion 17. The holder 21 is screwed (threadedly connected) to the mounting portion 17 of the valve body 10. A coupling hole 24 is formed on the inner peripheral surface of the holder 21. Note that the material of the holder 21 is preferably a material with relatively good corrosion resistance and machinability such as stainless steel. Also, an O-ring 22 is disposed at the bottom of the mounting portion 17 to seal so that the refrigerant does not leak.

[0022] The attractor 25 has a cylindrical shape. The lower end portion 25a of the attractor 25 protrudes outward on the outer peripheral side in a flange shape, and the outer diameter of the lower end portion 25a is larger than the outer diameter of the upper end portion 25b. The lower end portion 25a is disposed and fixed inside the coupling hole 24 of the holder 21. Specifically, the lower end portion 25a is brazed to the coupling hole 24. The outer diameter of the upper end portion 25b is the same as or slightly smaller than (substantially the same as) the inner diameter of the case 32.

[0023] The attractor 25 of this embodiment is made of free-cutting steel having soft magnetism. As the material of the attractor 25, magnetic stainless steel may be used, but a material with high magnetic permeability and low coercive force is preferred.

[0024] The case 32 is made of non-magnetic stainless steel. The case 32 has a cylindrical shape, with an open lower part and an upper part closed by a plug-shaped member 48. The inner diameter of the case 32 is the same (substantially the same) as the outer diameter of the upper end portion 25b of the attractor 25. The plug-shaped member 48 is airtightly fixed to the case 32 by welding. The case 32 is inserted into the outer peripheral portion of the upper end portion 25b of the attractor 25 and brazed to the attractor 25 in a state of being placed on the upper surface (case receiving surface 26) of the lower end portion 25a. Note that both the fixing of the holder 21 to the attractor 25 and the fixing of the attractor 25 to the case 32 are performed by brazing. The fixing structure of the connector 20 will be described later.

[0025] The plug-shaped member 48 is made of a magnetic material and consists of a cylindrical head portion 48a with a large outer diameter that closes the upper surface opening of the case 32 and a cylindrical leg portion 48b with a small outer diameter that extends vertically downward from the lower surface of the head portion 48a. A female screw 50 is formed from the upper surface of the head portion 48a at the center of the head portion 48a. The female screw 50 is screwed with a bolt 51 that fixes the housing 34b of the electromagnetic coil 34 (described later). Further, the plug-shaped member 48 also functions as a stopper for stopping the plunger 33 that moves upward when the valve is opened. Note that in the present embodiment, in order to prevent the plug-shaped member 48 and the plunger 33 from coming into contact and not separating, a resin or metal ring member 49 is interposed between the plug-shaped member 48 and the plunger 33.

[0026] The plunger 33 has a cylindrical shape. The outer diameter of the plunger 33 is slightly smaller than the inner diameter of the case 32. The plunger 33 is arranged inside the case 32 so as to be movable in the vertical direction. A plunger spring 38 is arranged between the plunger 33 and the attractor 25. The plunger spring 38 is a compression coil spring. The plunger spring 38 presses the plunger 33 upward.

[0027] The electromagnetic coil 34 is configured by surrounding the bobbin around which the coil 34a is wound with a housing 34b formed of a magnetic material. The electromagnetic coil 34 is disposed outside the case 32, and the upper plate portion of the housing 34b is fixed to the plug-shaped member 48 via the bolt 51. The electromagnetic coil 34 magnetizes the attractor 25, the plunger 33, the plug-shaped member 48, and the housing 34b. Also, a wave washer 44 as an elastic member is shrink-fitted in the gap between the bottom of the electromagnetic coil 34 and the valve body side (specifically, the gap between the lower plate portion of the housing 34b and the case receiving surface 26 of the lower end portion 25a of the attractor 25).

[0028] Note that when the bolt 51 is tightened to fix the top plate portion of the housing 34b to the plug-shaped member 48, the wave washer 44 is compressed and elastically deformed so as to be in pressure contact (contacted in a pressed state) with both the lower plate portion of the housing 34b and the case receiving surface 26 of the lower end portion 25a of the attractor 25. Thereby, even if there are variations (tolerances) in the dimensions of the housing 34b and the fixing position of the electromagnetic coil 34 in the vertical direction due to the bolt 51, this is absorbed to prevent the generation of a gap, and the lower plate portion of the housing 34b, the wave washer 55, and the lower end portion 25a can be made to closely contact each other to form a good magnetic path. Also, a spring washer may be used instead of the wave washer 55.

[0029] The valve shaft 35 is shaft-shaped or rod-shaped. The upper end portion of the valve shaft 35 is fixed to the lower end portion of the plunger 33. The valve shaft 35 is disposed so as to penetrate the attractor 25. The valve shaft 35 is supported by the attractor 25 so as to be movable in the vertical direction. The valve shaft 35 has a fluid passage 35a, and the fluid passage 35a connects the inner space and the outer space of the plunger 33. The pilot valve body 36 is fixed to the lower end portion of the valve shaft 35. The pilot valve body 36 is a packing made of a disk-shaped synthetic resin.

[0030] The main valve body 40 is disposed inside the main valve chamber 14 so as to be movable in the vertical direction, and partitions the main valve chamber 14 and the pilot valve chamber 37. The main valve body 40 has a pilot valve port 45 penetrating in the vertical direction. The pilot valve port 45 connects the main valve port 15 and the pilot valve chamber 37. At the upper surface of the main valve body 40, the upper end of the pilot valve port 45 is open, and a pilot valve seat 46 surrounding the pilot valve port 45 is formed.

[0031] The main valve body 40 has a pressure equalizing passage 42a connecting the main valve chamber 14 and the pilot valve chamber 37. A groove is formed on the outer peripheral surface of the upper side of the main valve body 40 to accommodate the piston ring 42. A disk-shaped packing 43 is attached to the lower surface of the main valve body 40. The packing 43 is made of, for example, synthetic resin. An opening valve spring 39 is disposed between the main valve body 40 and the valve body 10. The opening valve spring 39 is a compression coil spring and presses the main valve body 40 upward.

[0032] In the solenoid valve 1, the inner spaces of the main valve chamber 14, the pilot valve chamber 37, and the case 32 are spaces into which the refrigerant is introduced, and are sealed from the atmosphere outside the case 32.

[0033] Next, an example of the operation of the solenoid valve 1 will be described.

[0034] In the solenoid valve 1 shown in FIG. 1, the electromagnetic coil 34 is in a non-energized state. In this state, the pilot valve body 36 is separated from the pilot valve seat 46, and the pilot valve port 45 is open. The refrigerant pressure in the main valve chamber 14 is greater than the refrigerant pressure in the pilot valve chamber 37, and the main valve body 40 is pushed upward by the differential pressure and separated from the main valve seat 16, and the main valve port 15 is open. The solenoid valve 1 is in an open valve state.

[0035] When the compressor (not shown) of the refrigeration cycle is stopped, the pressure difference between the refrigerant pressure in the main valve chamber 14 and the refrigerant pressure in the pilot valve chamber 37 disappears or becomes small. Therefore, the main valve body 40 is pushed upward by the opening valve spring 39 and separated from the main valve seat 16, and becomes an open valve state.

[0036] When the electromagnetic coil 34 is energized, the armature 25 and the plunger 33 are magnetized, and the plunger 33 approaches the armature 25 against the elastic force of the plunger spring 38. When the pilot valve body 36 moves together with the plunger 33 and closes the pilot valve port 45, refrigerant flows from the pressure equalizing passage 42a (accurately, the gap between the inner peripheral surface of the main valve chamber 14 and the outer peripheral surface of the main valve body 40 and the pressure equalizing passage 42a) into the pilot valve chamber 37, and the refrigerant pressure in the pilot valve chamber 37 becomes higher than the refrigerant pressure in the main valve chamber 14. Due to this differential pressure, the main valve body 40 is pushed toward the main valve port 15 side. Then, the main valve body 40 closes the main valve port 15, and the solenoid valve 1 enters a closed state.

[0037] When the electromagnetic coil 34 is de-energized again, the magnetization of the armature 25 and the plunger 33 is cancelled, and the plunger 33 is pushed by the plunger spring 38 and moves away from the armature 25. The pilot valve body 36 moves together with the plunger 33, and the pilot valve port 45 opens. Refrigerant flows from the pilot valve chamber 37 through the pilot valve port 45 to the main valve port 15, and since the refrigerant pressure in the main valve chamber 14 becomes higher than the refrigerant pressure in the pilot valve chamber 37, the main valve body 40 moves upward (in the opening direction), and the solenoid valve 1 enters an open state.

[0038] The connector 20, which is a characteristic configuration of the present invention, will be described.

[0039] FIG. 2 is an explanatory diagram of the connector 20. The connector 20 is connected at both connection points by brazing. In the brazing process, it is introduced into a brazing furnace in the assembled state shown in FIG. 2. FIG. 2 shows a state where the holder 21, the armature 25, and the case 32 are placed in this order. At this time, the brazing material 53a is placed in the gap between the holder 21 and the armature 25. The brazing material 53b is placed between the armature 25 and the case 32. Also, the case 32 is placed so as to be inserted into the outer peripheral portion of the armature 25. By performing brazing in this way, the holder 21, the armature 25, and the case 32 can be integrally fixed in a single brazing process. That is, the brazing process for manufacturing the connector 20 simultaneously performs brazing of the holder and the armature and brazing of the armature and the case.

[0040] Note that the brazing materials 53a and 53b are brazing materials formed in a ring shape (so-called ring brazing). The holder 21 supports the lower end portion 25a of the attractor 25 by the inner flange portion 24a of the coupling hole 24, and the attractor 25 supports the case 32 by the lower end portion 25a.

[0041] In the brazing process of the present embodiment, the brazing material 53a disposed in the gap between the holder 21 and the attractor 25 and the brazing material 53b disposed between the attractor 25 and the case 32 are in relatively close positions. The materials of the brazing materials 53a and 53b are the same, and both are in contact with the attractor 25. For this reason, even if there is some deviation in the temperature distribution of the brazing furnace, the brazing materials 53a and 53b will reach the same temperature, so it is difficult for brazing defects to occur in the brazing process.

[0042] A tapered portion 21b is formed on the upper end side of the coupling hole 24 of the holder 21 so as to widen the gap. The brazing material 53a is disposed in a recess formed between the tapered portion 21b and the attractor 25. The tapered portion 21b facilitates the arrangement of the brazing material 53a and makes it difficult for the melted brazing material (53a) to flow out, so that it easily penetrates between the holder 21 and the attractor 25. In the connector after brazing, the connection portion between the holder 21 and the attractor 25 and the connection portion between the attractor 25 and the case 32 are in a state having solidified brazing, and sufficient connection strength is ensured for the connection portion.

[0043] The attractor 25 has a recess 25c on the outer peripheral surface at a height continuous with the case receiving surface 26 which is the upper surface of the lower end portion 25a, facilitating the arrangement of the brazing material 53b and allowing the melted brazing material 53b in the brazing furnace to easily penetrate between the attractor 25 and the case 32. Since the melted brazing material (53b) penetrates into the gap between the outer peripheral portion of the attractor 25 and the case 32 and solidifies, sufficient connection strength can be ensured for the connection portion.

[0044] Since the solder material 53b is substantially disposed on the case receiving surface 26 of the lower end portion 25a, there is no concern about the positional deviation of the solder material 53b before melting. Even if a part of the melted solder material (53b) overflows outside the case 32, it only spreads on the case receiving surface 26 of the lower end portion 25a. Therefore, no solder material adheres to the outer peripheral portion of the case 32, and the attachment of the electromagnetic coil 34 is not hindered. Note that the recess 25c is not an essential configuration, and the solder material 53b may be arranged so as to be sandwiched between the lower end portion 25a and the lower end of the case 32.

[0045] According to the present invention, the amount of machining and the number of machining steps of the holder 21 and the armature 25 can be reduced, and a connecting body 20 in which the case, the armature, and the holder are integrally fixed can be manufactured in a single soldering process. Therefore, it can contribute to the improvement of workability during the manufacture of the solenoid valve and the cost reduction of the solenoid valve. Further, since there is no welding portion in the portion where the electromagnetic coil 34 is arranged, the attachment of the electromagnetic coil 34 becomes smooth.

[0046] As described above, one embodiment of the present invention has been described. However, the present invention is not limited to the above-described embodiment. Those obtained by appropriately adding, deleting, or changing the design of components to the above-described embodiment are also included in the scope of the present invention as long as they do not depart from the spirit of the present invention. For example, a locking structure using a clip or a pin instead of the bolt 51 in the above-described embodiment may be adopted.

[0047] In the description of the above embodiment, it has been described that a pilot valve 36 separate from the valve shaft 35 is provided and a main valve packing 43 is provided on the lower surface of the main valve body 40. However, the present invention is not limited to this, and a configuration in which the pilot valve 36 and / or the packing 43 is substituted with another configuration may be adopted as long as the pilot valve seat 46 and / or the main valve seat 16 can be closed well.

[0048] Furthermore, although the solenoid valve according to the above-described embodiment is a normally open type pilot solenoid valve, the present invention is not limited to such a pilot solenoid valve. The connector 20, which is a characteristic configuration of the present invention, can also be applied to a direct acting solenoid valve. For example, a direct acting solenoid valve does not include a main valve body as in the above-described embodiment, and has a configuration in which a valve portion attached to a plunger opens and closes a main valve seat. Such a direct acting solenoid valve can also employ a connection portion and the connector 20 attached to the case.

[0049] Furthermore, the solenoid valve according to the present invention can typically be preferably used in a refrigeration cycle apparatus equipped with a refrigerant circuit such as an air conditioner (air conditioner), a refrigerator, or a freezer, but is not limited thereto, and the solenoid valve according to the present invention can also be used in various other applications.

Explanation of Reference Numerals

[0050] 1... Solenoid valve, 10... Valve body, 11... Inlet port, 12... Outlet port, 14... Main valve chamber, 15... Main valve port, 16... Main valve seat, 17... Mounting portion, 20... Connector, 21... Holder, 24... Coupling hole, 24a... Flange portion, 25... Armature, 25a... Lower end portion, 25b... Upper end portion, 25c... Concave portion, 26... Case receiving surface, 32... Case, 33... Plunger, 34... Electromagnetic coil, 35... Valve shaft, 35a... Fluid passage, 36... Pilot valve body, 37... Pilot valve chamber, 38... Plunger spring, 39... Valve opening spring, 40... Main valve body, 42... Piston ring, 42a... Equalizing passage, 43... Packing, 44... Wave washer, 45... Pilot valve port, 46... Pilot valve seat, 48... Plug-shaped member, 49... Ring member, 51... Bolt, 53a, 53b... Brazing material

Claims

1. A valve body having a valve port, a case in which a plunger is disposed inside and an electromagnetic coil is attached outside, a holder connected to the valve body, and a connecting body integrally fixing an attractor that attracts the plunger, a valve body that is connected to the plunger via a valve shaft and opens and closes the valve port, and an electromagnetic valve having the same, wherein the connecting body has brazing at a connecting portion between the holder and the attractor and at a connecting portion between the attractor and the case. The electromagnetic valve is characterized by this.

2. A valve body, a main valve body that opens and closes a main valve port in the valve body, a case in which a plunger is disposed inside and an electromagnetic coil is attached outside, a holder connected to the valve body, and a connecting body integrally fixing an attractor that attracts the plunger, and a pilot valve body that is connected to the plunger via a valve shaft and opens and closes a pilot valve port in the main valve body, and an electromagnetic valve having the same, wherein the connecting body has brazing at a connecting portion between the holder and the attractor and at a connecting portion between the attractor and the case. The electromagnetic valve is characterized by this.

3. The electromagnetic valve according to claim 1 or 2, wherein an upper end portion of the attractor is disposed inside the case.

4. The holder has a coupling hole to which a lower end portion side of the attractor is fixed, The electromagnetic valve according to claim 1 or 2, wherein the attractor has a case receiving surface on which the case is placed.

5. The electromagnetic valve according to claim 4, wherein the coupling hole has a tapered portion on an upper end side.

6. The electromagnetic valve according to claim 4 or 5, further comprising an elastic member made of a magnetic material that is shrink-fitted in a gap between a bottom portion of the electromagnetic coil and the case receiving surface of the attractor.

7. The electromagnetic valve according to claim 6, wherein the elastic member is a wave washer or a spring washer.

8. A valve body having a valve port, a case in which a plunger is disposed inside and an electromagnetic coil is attached outside, a holder connected to the valve body, and a connecting body integrally fixing an attractor that attracts the plunger, a valve body that is connected to the plunger via a valve shaft and opens and closes the valve port, and a method for manufacturing an electromagnetic valve having the same, The method for manufacturing an electromagnetic valve is characterized by having a brazing step of manufacturing the connecting body by simultaneously performing brazing of the holder and the attractor and brazing of the attractor and the case.

9. A manufacturing method of a solenoid valve, comprising: a valve body; a main valve body that opens and closes a main valve port in the valve body; a case that disposes a plunger inside and mounts an electromagnetic coil outside; a holder connected to the valve body; and a connection body in which an attractor that attracts the plunger is integrally fixed; and a pilot valve body that is connected to the plunger via a valve shaft and opens and closes a pilot valve port in the main valve body. The manufacturing method of a solenoid valve is characterized by having a brazing step of manufacturing the connection body by simultaneously brazing the holder and the attractor and brazing the attractor and the case.

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