JP2017198373A - Expansion valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an expansion valve that can obtain both of large flow rate mode characteristics at start and steady flow rate mode characteristics during a steady operation.SOLUTION: An expansion valve includes: a valve body 11; a first valve member having a through hole at the center thereof and opened/closed by coming into contact with a valve seat 25; a second valve member 40 opened/closed by coming into contact with the through hole of the first valve member; a support member 42 for supporting the second valve member; a first coil spring 44 for supporting the support member; a second coil spring interposed between the first valve member and the support member; and a valve rod 60 mounted to a power element 12 to drive the first valve member and the second valve member.The valve rod is disposed so that an end on the valve chamber 24 side thereof is inserted into the through hole and an end surface of the valve rod comes into contact with the second valve member.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a temperature sensing mechanism built-in type expansion valve used in a refrigeration cycle, and more particularly to an expansion valve having a power element attached to a valve body.

Conventionally, for refrigeration cycles used in air conditioners installed in automobiles, a temperature expansion valve with a built-in temperature sensing mechanism that adjusts the refrigerant flow rate according to the temperature is used to save installation space and piping work. Has been. The valve body of such an expansion valve has an inlet port into which high-pressure refrigerant is introduced and a valve chamber communicating with the inlet port, and a valve member drive mechanism called a power element is provided on the top of the valve body. Is done.
A spherical valve member disposed in the valve chamber is opposed to the valve seat in the valve hole that opens to the valve chamber, and is operated by a valve rod driven by a power element to open a throttle passage between the valve seat and the valve seat. Control the degree.
Moreover, the refrigerant | coolant which passed the valve hole is sent to an evaporator side from an exit port. The refrigerant returning from the evaporator to the compressor side passes through a return passage provided in the valve body.

The power element is composed of an upper lid member that forms a pressure working chamber, a thin diaphragm that is elastically deformed under pressure, and a disk-shaped receiving member. The three members are overlapped and the circumference is joined by TIG welding means, etc. Formed. A stopper member is sandwiched between the diaphragm and the receiving member.
A working gas is sealed in a pressure working chamber formed by the upper lid member and the diaphragm. At this time, in order to enclose the working gas in the pressure working chamber, a hole is provided in the top of the upper lid member, and after filling the working gas from this hole, the hole is closed with a steel ball or the like, and the pressure working chamber is sealed by projection welding means or the like. Stop.

  As a conventional temperature expansion valve with a built-in temperature sensing mechanism as described above, a male screw and a female screw are formed on the opening formed at the top of the valve body of the expansion valve and the bottom of the power element, respectively, and these are tightened. Are known (for example, see Patent Document 1).

JP-A-2005-164208

When starting up a general air conditioner, it is necessary to supply as much refrigerant as possible to increase the amount of heat exchange. However, when shifting to steady operation, fine temperature control is required according to the temperature change in the room. The expansion valve is required to perform finer flow control than a large flow rate.
However, when trying to match the control characteristics at the time of startup, for example, in the expansion valve described in Patent Document 1, the flow rate of the expansion valve is increased by increasing the opening area of the valve seat formed in the valve hole. Can be bigger.
On the other hand, when the opening area of the valve seat is increased, the size of the valve body is also relatively increased, and the flow rate change amount with respect to the lift amount of the valve body is also increased. There is a problem that it is difficult to perform fine flow rate control.

  Accordingly, an object of the present invention is to provide an expansion valve that can achieve both a large flow rate mode characteristic during startup and a steady flow mode characteristic during steady operation.

  To achieve the above object, an expansion valve according to the present invention includes a power element including an upper lid member, a receiving member, and a diaphragm sandwiched between the upper lid member and the receiving member, an inlet port, and the inlet. A valve chamber communicating with the port; a valve hole communicating with the valve chamber; an outlet port communicating with the valve hole; a valve seat formed at an opening of the valve hole on the valve chamber side; and a power element mounting A valve body including a first portion, a first valve member having a through hole in a central portion thereof, opening and closing in contact with the valve seat, and opening and closing in contact with the through hole of the first valve member A second valve member; a support member that supports the second valve member; a first coil spring that supports the support member; and a first member interposed between the first valve member and the support member. 2 coil springs and attached to the power element And a valve rod that drives the first valve member and the second valve member, and the valve rod is disposed such that an end portion on the valve chamber side is inserted into the through hole. And the end surface contacts the said 2nd valve member, It is characterized by the above-mentioned.

In an example of the expansion valve according to the present invention, the first valve member is a cylindrical member, and a tapered surface toward the upper surface thereof is formed on the outer peripheral surface.
The first valve member has a stepped portion on the outer peripheral portion of the lower surface, and one end of the second coil spring is disposed on the stepped portion of the first valve member.

In another example of the expansion valve according to the present invention, the second valve member may be disposed inside the second coil spring.
Furthermore, a small-diameter portion and a step portion are formed at an end portion of the valve stem on the valve chamber side, and the step portion contacts the upper surface of the first valve member or faces the end surface. A tapered side surface having a reduced diameter may be formed, and the tapered side surface may be configured to contact an opening end of the through hole of the first valve member.

According to the expansion valve of the present invention, it is possible to provide an expansion valve that can achieve both a large flow rate mode characteristic during startup and a steady flow mode characteristic during steady operation.
In addition, since it is not necessary to increase the size of the second valve member, the conventional support member, the first coil spring, or the valve chamber that supports the second valve member can be used as it is. Cost increase due to accompanying specification changes can be suppressed.

It is a longitudinal section showing an expansion valve by a typical example of the present invention. It is a fragmentary sectional view which shows the detail of the valve structure of the expansion valve shown in FIG. FIGS. 3A and 3B are diagrams schematically illustrating a first valve member according to a typical example of the present invention, in which FIG. 3A is a top view and FIG. 3B is a cross-sectional view of a plane passing through the center. It is sectional drawing which shows the outline of the end of the valve stem by a typical example of this invention. It is a fragmentary sectional view which shows the steady flow mode state of the valve structure of the expansion valve shown in FIG. It is a fragmentary sectional view which shows the large flow rate mode state of the valve structure of the expansion valve shown in FIG. It is a graph which shows an example of the flow characteristic by the expansion valve of the present invention. It is a fragmentary sectional view which shows the detail of the modification of the valve structure in the expansion valve by this invention.

FIG. 1 is a longitudinal sectional view showing an expansion valve according to a typical example of the present invention.
As shown in FIG. 1, the expansion valve 10 includes a valve body 11, a power element 70, a valve structure 100, an adjustment screw 50, and a valve stem 60.

The valve body 11 of the expansion valve 10 is made of, for example, an aluminum alloy, and can be obtained by extruding an aluminum alloy or the like with the X direction shown in FIG.
The valve body 11 includes a power element mounting portion 12 formed on the upper surface portion and having an internal thread, an inlet port 20 into which a high-pressure refrigerant is introduced, a refrigerant outlet port 28, a refrigerant return passage 30, and the valve body 11. 1 and two holes (not shown) penetrating in the X direction of FIG. 1 and mounting holes (or female threads for mounting) 80 for mounting the valve body 11 to other components.

A female screw hole 11 a that opens to the lower end is formed in the lower part of the valve body 11, and the valve chamber 24 is formed by sealing the opening of the female screw hole 11 a with a plug 50. Further, the inlet port 20 communicates with the valve chamber 24 from the side through a small diameter hole 20a.
On the other hand, an outlet port 28 is formed above the valve chamber 24 in the valve body 11. The outlet port 28 communicates with the upper end portion of the valve chamber 24 through the valve hole 26, and a valve seat 25 is formed on the valve chamber 24 side of the valve hole 26.

The plug 50 is attached in such a manner that it is screwed into the female screw hole 11a opened at the lower end of the valve body 11, and a tool is inserted into the hexagonal hole 53 formed on the surface facing the concave portion 52 and rotated. The screwing amount can be adjusted.
Further, a seal member 54 is provided on the outer peripheral portion of the plug 50, thereby sealing the valve chamber 24.

A return passage 30 is formed further above the outlet port 28 in the valve body 11 so as to penetrate the valve body 11 in the X direction in FIG.
The refrigerant flowing through the expansion valve 10 of the present invention flows in from the inlet port 20, passes through the valve hole 26, is sent out from the outlet port 28, is sent to an evaporator (not shown), and then the refrigerant evaporates. Return from compressor to compressor (not shown).
The refrigerant returning from the evaporator to the compressor passes from the left side of the return passage 30 in FIG.

A power element attachment portion 12 for attaching a power element 70 described later is formed further above the return passage 30 in the valve body 11.
The power element attachment portion 12 is formed as a bottomed cylindrical hole having a circular opening on the upper surface of the valve body 11 at the upper end of the valve body 11 and having an internal thread on the inner wall surface thereof.
Further, a communication hole 31 reaching the return passage 30 is formed in the central portion of the power element mounting portion 12, and a later-described valve rod 60 is inserted therethrough.

The power element 70 includes an upper lid member 71 formed of, for example, stainless steel, a receiving member 72 having a through-hole in the center, a diaphragm 73 sandwiched between the upper lid member 71 and the receiving member 72, and the diaphragm 73 and a stopper member 90 disposed between the receiving member 72 and the receiving member 72.
And the end part which piled up the upper cover member 71, the diaphragm 73, and the receiving member 72 is circumferential-welded, and these are integrated.

A pressure working chamber 75 is formed between the upper lid member 71 and the diaphragm 73. After the working gas is sealed in the pressure working chamber 75, the pressure working chamber 75 is sealed with a sealing plug 76.
The lower portion of the receiving member 72 is cylindrical, and a male screw 72a is formed around the lower portion. The screw 72a is attached to the power element mounting portion 12 by being screwed with the female screw of the power element mounting portion 12 described above.
At this time, the packing 35 is interposed between the power element 70 and the valve body 11.

A through hole 29 is formed between the outlet port 28 and the return passage 30. And the valve hole 26, the through-hole 29, and the communication hole 31 are arrange | positioned so that a center may respectively be on the same straight line.
Further, a valve rod 60 is provided in such a manner as to be inserted into each of the valve hole 26, the through hole 29, and the communication hole 31.

The upper end side of the valve stem 60 is in contact with a receiving portion 92 formed on the lower surface of the stopper member 90 of the power element 70, and the lower end side thereof is in contact with the first valve member 110 and the second valve member 40. Placed in.
With such an arrangement, the expansion valve 10 shown in FIG. 1 receives the movement of the diaphragm 73 deformed according to the fluctuation of the internal pressure in the pressure working chamber 75 of the power element 70, and the stopper member 90 moves up and down. The movement of the stopper member 90 is transmitted to the first valve member 110 and the second valve member 40 of the valve structure 100 via the valve rod 60, and can serve as an expansion valve.
The through hole 29 is provided with a spring member 66 that adds sliding resistance to the outer peripheral surface of the valve stem 60, and vibrations between the valve stem 60 and the first valve member 110 and the second valve member 40. To prevent.

FIG. 2 is a partial cross-sectional view showing details of the valve structure of the expansion valve shown in FIG. FIG. 2 shows a case where the expansion valve is fully closed.
As shown in FIG. 2, a valve hole (orifice) 26 having a valve seat 25 is formed between the valve chamber 24 and the outlet port 28.

The valve chamber 24 houses a valve structure 100 that opens and closes the valve hole 26 through which the refrigerant flows by contacting or separating from the valve seat 25.
The valve structure 100 includes a first valve member 110 having a through hole at the center and opening and closing in contact with the valve seat 25, and a second valve opening and closing in contact with the through hole of the first valve member 110. The valve member 40, the support member 42 that supports the second valve member 40, the first coil spring 44 that supports the support member 42, and the first valve member 110 and the support member 42 that are interposed between the first valve member 110 and the support member 42. 2 coil springs 120.

The support member 42 includes an upper surface 42a having a conical recess for supporting the second valve member 40, and a flange portion 42b protruding to the side surface, and the lower surface of the flange portion 42b is the first coil. The structure is such that one end of the spring 44 is received.
The first coil spring 44 is accommodated between the lower surface of the flange portion 42b provided in the support member 42 and the recess 52 formed in the plug 50, whereby the second valve member 40 is supported by the support member. The valve seat 25 is biased toward the side where the valve seat 25 is located.

The first valve member 110 is a cylindrical member, and its outer peripheral surface is in contact with the valve seat 25 in a fully closed state, and an open end surface of a through hole formed in the center (see reference numeral 113 in FIG. 3). ) Is in contact with the second valve member 40.
Further, a second coil spring 120 is interposed between the lower surface of the first valve member 110 and the upper surface of the flange portion 42b of the support member 42, and the second coil spring 120 is connected to the first coil member 120 by the first coil member 120. The valve member 110 is biased toward the valve seat 25.
The spring force of the first coil spring 44 and the second coil spring 120 can be adjusted by changing the screwing amount of the plug 50 to adjust the distance between the valve seat 25 and the bottom surface of the recess 52. .

The second valve member 40 is a ball-shaped member, and is placed on the upper surface 42a of the support member 42 inside the second coil spring 120. When the second valve member 40 is fully closed, the second valve member 40 is formed in the through hole of the first valve member 110. Contact with the open end face 113.
The valve rod 60 is disposed so as to pass through the through hole of the first valve member 110 such that the end surface of the valve rod 60 on the valve chamber 24 side contacts the second valve member 40.
Here, as shown in FIG. 2, the height from the upper surface of the first valve member 110 to the second valve member 40 in a state where the first valve member 110 and the second valve member 40 are in contact with each other. If the distance in the direction is H1, the insertion depth (pushing depth) L of the valve stem 60 in the fully closed state is L = H1.

3A and 3B are views schematically showing a first valve member according to a typical example of the present invention, in which FIG. 3A is a top view and FIG. 3B is a cross-sectional view taken along a plane passing through the center. It is.
As above-mentioned, the 1st valve member 110 is a cylindrical member, Comprising: The taper surface 111 which goes to an upper surface is formed in the outer peripheral surface.

A through hole 112 serving as a refrigerant passage is formed in the central portion of the first valve member 110, and a diameter-expanded tapered opening that comes into contact with the second valve member 40 is formed at an end portion on the lower surface side thereof. An end face 113 is provided.
In addition, four notches 114 are formed at equal intervals at the upper end of the opening end face 113 having an enlarged diameter tapered shape.

On the lower surface side of the first valve member 110, a stepped portion 115 having a reduced diameter is formed over the entire circumference.
The step portion 115 serves as a receiving portion that receives the upper end of the second coil spring 120 shown in FIG.

FIG. 4 is a cross-sectional view schematically showing one end of a valve stem according to a typical example of the present invention.
As shown in FIG. 4, the valve rod 60 applied to the expansion valve according to the present invention includes a reduced diameter portion 62 at the end located on the valve chamber 24 side shown in FIG. 1.
As a result, the end surface 62a and the stepped portion 60a of the small diameter portion 62 are formed, and the small diameter portion 62 is inserted through the through hole 112 of the first valve member 110, and the end surface 62a contacts the second valve member 40. To do.

Here, when the inner diameter of the through hole 112 in the first valve member 110 shown in FIG. 3 is D1, the diameter of the small diameter portion 62 of the valve stem 60 is D2, and the diameter of the valve stem 60 itself is D3, the three Is formed so that the relationship of “D2 <D1 <D3” is established.
Further, the protruding length H2 of the small diameter portion 62 is formed to be sufficiently larger than the distance H1 shown in FIG.

In the expansion valve according to the present invention, when the valve rod 60 attached to the stopper member 90 is pushed down in accordance with the variation of the diaphragm 73 of the power element 70 shown in FIG. 1, the end of the valve rod 60 on the valve chamber 24 side. The part pushes down the first valve member 110 and the second valve member 40.
As a result, a part of the valve hole 26 is opened and the refrigerant flows out from the valve chamber 24 to the outlet port 28. The opening / closing operation | movement with the 1st valve member 110 and the 2nd valve member 40 at this time is demonstrated using the following FIG.5 and FIG.6.

FIG. 5 is a partial cross-sectional view showing a steady flow mode state of the valve structure of the expansion valve shown in FIG.
As shown in FIG. 5, in the steady flow mode state, the small diameter portion 62 at the tip of the valve rod 60 is inserted into the through hole 112 of the first valve member 110, and the end surface 62 a pushes down the second valve member 40. .
At this time, the insertion depth L of the small diameter portion 62 of the valve stem 60 is set to satisfy “H1 <L <H2”.

In the steady flow mode state, the valve rod 60 and the first valve member 110 are not in contact with each other, and the small diameter portion 62 pushes down only the second valve member 40.
For this reason, the contact between the tapered surface 111 of the first valve member 110 and the valve seat 25 is maintained, and the first valve member 110 has a first valve member 110 between the opening end surface 113 and the second valve member 40. 1 gap G1 is formed.

Accordingly, in the steady flow mode state shown in FIG. 5, the valve seat 25 and the first valve member 110 are closed, and the first valve member 110 and the second valve member 40 are opened. It will be in the state.
At this time, the first gap G1 can also be adjusted by adjusting the insertion depth L between “H1 <L <H2”, so that the flow rate can be finely adjusted by the movement of the valve stem 60. It becomes possible.
Further, since the notch 114 is formed at the upper end of the first valve member 110, the flow rate between the upper surface of the first valve member 110 and the stepped portion 60a of the valve stem 60 increases, and the through hole 112 is formed. The flow of refrigerant passing through becomes smooth.

FIG. 6 is a partial cross-sectional view showing a large flow mode state of the valve structure of the expansion valve shown in FIG.
As shown in FIG. 6, in the large flow rate mode state, the small diameter portion 62 at the tip of the valve stem 60 has the stepped portion 60a of the valve stem 60 in contact with the upper surface of the first valve member 110 from the position shown in FIG. Thus, the first valve member 110 is also driven to a position where it is pushed down.
At this time, the insertion depth L of the small diameter portion 62 of the valve stem 60 is set to satisfy “H2 <L”.

In the large flow rate mode state, in addition to the first gap G1 between the first valve member 110 and the second valve member 40, the second gap is also present between the valve seat 25 and the first valve member 110. A gap G2 is formed.
Thereby, in the large flow rate mode state shown in FIG. 6, both the valve seat 25 and the first valve member 110 and between the first valve member 110 and the second valve member 40 are opened. It becomes the state.
At this time, since the second gap G2 can be adjusted by adjusting the insertion depth L in the range of “H2 <L”, compared to opening and closing with a conventional ball-shaped valve body, It becomes possible to flow a refrigerant having a larger flow rate.

FIG. 7 is a graph showing an example of a flow rate characteristic by the expansion valve of the present invention. Here, in the graph of FIG. 7, the “lift amount”, that is, the push-down amount of the valve stem 60 based on the fully closed state shown in FIG. 2 is adopted on the horizontal axis.
In the graph of FIG. 7, the two-dot chain line indicates the relationship between the lift amount and the flow rate of the expansion valve according to the conventional small flow rate characteristic, and the broken line indicates the lift amount and the flow rate of the expansion valve according to the conventional large flow rate characteristic. Showing the relationship.

As shown in FIG. 7, the expansion valve according to the present invention adjusts the lift amount to the range of the region R2 where the lift amount becomes “H2 <L” when starting the air conditioner or the like, as shown in FIG. The characteristic of the “large flow rate mode” in which the valve member 110 and the second valve member 40 and the valve seat 25 and the first valve member 110 are both opened is obtained.
At this time, by appropriately selecting the outer diameter of the first valve member 110, the inclination angle of the tapered surface 111, etc., it becomes possible to increase the opening diameter of the valve seat 25 with which the tapered surface 111 abuts. Thus, it is possible to control a larger flow rate as compared with the case where a conventional ball-shaped valve member is used.

On the other hand, at the time of steady operation where the operation of the air conditioner or the like is stable, the lift amount is adjusted to the range of the region R1 where “H1 <L <H2”, so that the first valve member 110 of the first valve member 110 is adjusted as shown in FIG. The characteristic by the “steady flow mode” in which only the opening end surface 113 and the second valve member 40 are opened is obtained.
At this time, the contact between the first valve member 110 and the second valve member 40 is apparently equivalent to the relationship between the valve seat and the valve member of the conventional expansion valve. The same size as that of the conventional type can be used.

With the configuration shown above, according to the expansion valve of the present invention, the characteristics of the large flow rate mode mainly for opening and closing between the valve seat and the first valve member, the first valve member and the second valve member are provided. It is possible to switch and use the characteristic of the steady flow rate mode by opening and closing with the valve member by adjusting the lift amount according to the push-in depth of the valve rod.
In addition, since it is not necessary to increase the size of the second valve member, the conventional support member, the first coil spring, or the valve chamber that supports the second valve member can be used as it is. Cost increase due to accompanying specification changes can be suppressed.

FIG. 8 is a partial cross-sectional view showing details of a modification of the valve structure in the expansion valve according to the present invention.
FIG. 8 shows a state in which the expansion valve is used in the large flow rate mode. When the same configuration as that shown in FIGS. 1 to 6 is used, the same reference numeral is given. Will not be described again.

As shown in FIG. 8, in the expansion valve according to the modification of the present invention, a reduced diameter small diameter portion 62 and an inclined surface 60 c reaching the small diameter portion 62 are formed at the end of the valve rod 60 on the valve chamber 24 side. Has been.
Then, the end surface 62a of the small diameter portion 62 comes into contact with the second valve member 40 and is pushed down, and the inclined surface 60c comes into contact with the upper end of the through hole 112 of the first valve member 110 and pushes down.

With such a configuration, in addition to the above effect, the shape of the root of the small diameter portion 62 is continuously thickened, so that the strength of the tip of the valve stem 60 is improved and the small diameter portion 62 stands upright. Processing becomes easy.
In addition, since the inclined surface 60c is formed as a surface that smoothly expands in diameter, the refrigerant that passes through the through hole 112 of the first valve member 110 can flow smoothly without stagnation.

As described above, the expansion valve according to the present invention has been described based on typical examples thereof, but the present invention is not limited to the above specific examples, and various modifications can be made.
For example, the case where a ball-shaped member is used as the second valve member is illustrated, but if it can be closed by contacting a through hole formed in the first valve member, for example, a conical shape or a truncated cone shape Other shapes such as the above may be adopted.
Further, the second valve member and the support member may be formed as separate bodies, but may be formed as an integrated object.

Furthermore, in the above specific example, the case where the power element is attached to the upper end of the valve body by screwing is illustrated, but besides this, a cylindrical part is formed on the upper part of the valve body, and the power element is inserted inside this cylindrical part. In this state, a configuration in which the power element is attached may be used by caulking the cylindrical portion.
In addition, various modifications can be made to the above-described embodiment without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 10 Expansion valve 11 Valve main body 12 Power element attaching part 20 Inlet port 24 Valve chamber 25 Valve seat 26 Valve hole 28 Outlet port 29 Through hole 30 Return passage 31 Communication hole 40 2nd valve member 42 Support member 44 1st coil spring 50 Plug 54 Seal member 60 Valve rod 60a Step portion 62 Small diameter portion 62a End surface 70 Power element 71 Upper lid member 72 Receiving member 73 Diaphragm 75 Pressure operating chamber 90 Stopper member 100 Valve structure 110 First valve member 111 Tapered surface 112 Through hole 113 Open end face 114 Notch 115 Step part 120 Second coil spring

Claims (6)

A power element including an upper lid member, a receiving member, and a diaphragm sandwiched between the upper lid member and the receiving member;
An inlet port, a valve chamber communicating with the inlet port, a valve hole communicating with the valve chamber, an outlet port communicating with the valve hole, and a valve formed at an opening of the valve hole on the valve chamber side A valve body including a seat and a power element mounting portion;
A first valve member having a through hole in a central portion and opening and closing in contact with the valve seat;
A second valve member that opens and closes in contact with the through hole of the first valve member;
A support member for supporting the second valve member;
A first coil spring that supports the support member;
A second coil spring interposed between the first valve member and the support member;
A valve stem attached to the power element for driving the first valve member and the second valve member;
With
The said valve stem is arrange | positioned so that the edge part by the side of the said valve chamber may be inserted in the said through-hole, and the end surface contacts the said 2nd valve member, The expansion valve characterized by the above-mentioned. 2. The expansion valve according to claim 1, wherein the first valve member is a cylindrical member, and a tapered surface toward an upper surface thereof is formed on an outer peripheral surface. The first valve member has a step portion on the outer peripheral portion of the lower surface,
The expansion valve according to claim 1 or 2, wherein one end of the second coil spring is disposed in the step portion of the first valve member. The expansion valve according to any one of claims 1 to 3, wherein the second valve member is disposed inside the second coil spring. A small diameter portion and a step portion are formed at an end portion of the valve stem on the valve chamber side, and the step portion is in contact with the upper surface of the first valve member. The expansion valve according to any one of the above. A tapered side surface that is reduced in diameter toward the end surface is formed at an end of the valve stem on the valve chamber side, and the tapered side surface is an opening of the through hole of the first valve member. The expansion valve according to any one of claims 1 to 4, wherein the expansion valve is in contact with an end.

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