JP2022147972A - expansion valve - Google Patents

Abstract

To prevent corrosion of a working fluid sealing part.SOLUTION: In an expansion valve 51, a diaphragm device 61 that drives a valve body 8 includes: a lower casing 22; an upper casing 52 covering an upper face of the lower casing; a diaphragm 24 arranged between the lower casing and the upper casing so as to form, between the diaphragm and the lower casing, a refrigerant introduction chamber 26 communicating with a return passage 5, and also form, between the diaphragm and the upper casing, a working fluid sealing chamber 27 sealing working fluid; a fluid injection port 53 formed on a top part 52a of the upper casing so as to inject the working fluid to the working fluid sealing chamber; and a closing member 54 that closes the fluid injection port by being welded to the upper casing so as to cover the fluid injection port from the above. The top part of the upper casing has a bottomless and lidless truncated cone shape, and at least a portion of a top face of the top part on the outside of the welded part where it is joined with the closing member, is an inclined plane forming a descending graduation toward an outward direction.SELECTED DRAWING: Figure 1

Description

The present invention relates to an expansion valve used in a refrigeration cycle device such as an air conditioner, and more particularly to a structure for sealing an opening for charging a working fluid into a diaphragm device provided in the expansion valve.

A refrigerating cycle device such as a car air conditioner is provided with an expansion valve in order to fully draw out the performance of an evaporator. FIG. 17 shows such an expansion valve. As shown in the figure, the expansion valve 1 supplies refrigerant from a condenser 42 to the evaporator 44 in response to the temperature of the refrigerant in the outlet pipe of the evaporator 44. between the inflow path 3 into which the refrigerant sent from the condenser 42 via the receiver tank 43 flows and the outflow path 4 from which the refrigerant is delivered to the evaporator 44. A flow rate of the refrigerant is adjusted by the provided valve body 8 . The valve body 8 is supported so as to move forward and backward relative to a valve seat 7 formed in the valve chamber 6 and is driven by a diaphragm device 21 via an operating rod 9 .

The diaphragm device 21 that operates the valve body 8 includes a dish-shaped lower housing 22 that has an opening 10 in the center and is fixed to the upper surface of the valve body 2, and a lid-shaped upper housing that covers the upper surface of the lower housing 22. It has a body 23 and a diaphragm 24 sandwiched between the lower housing 22 and the upper housing 23 . The internal space on the upper side of the device with the diaphragm 24 interposed therebetween, that is, the space formed by the diaphragm 24 and the upper housing 23 is a working fluid enclosing chamber 27 that encloses a working fluid (for example, working gas). The upper end of the operating rod 9 is connected to the lower surface of the diaphragm 24 via the operating rod receiving member 25 , and the lower end of the operating rod 9 is in contact with the valve body 8 .

On the other hand, the inner space on the lower side of the device with the diaphragm 24 interposed therebetween, that is, the space formed by the diaphragm 24 and the lower housing 22 communicated with the return flow path 5 through the opening 10 at the center of the lower housing 22 described above. A refrigerant introduction chamber 26 is provided. The return flow path 5 is a flow path through which the refrigerant sent from the evaporator 44 to the compressor 41 passes. of the working fluid changes in pressure and volume.

When the pressure of the working fluid in the working fluid sealed chamber 27 decreases, the diaphragm 24 is pulled upward according to the pressure difference from the refrigerant introduction chamber 26, and the working rod 9 follows the diaphragm 24 and moves upward. As a result, the valve body 8 advances toward the valve seat 7 and the refrigerant flow rate is throttled. Conversely, when the pressure of the working fluid increases, the diaphragm 24 is pushed downward according to the difference from the pressure in the refrigerant introduction chamber 26, and the operating rod 9 follows the diaphragm 24 to move downward, causing the valve body 8 to move downward. retreats from the valve seat 7 and the refrigerant flow rate increases. In this manner, the expansion valve 1 adjusts the amount of refrigerant supplied from the expansion valve 1 to the evaporator 44 in accordance with the temperature and pressure of the refrigerant returning from the evaporator 44 to the expansion valve 1 .

In fabricating the diaphragm device 21, the lower housing 22 and the upper housing 23 are overlapped so as to sandwich the diaphragm 24, and the working fluid from the working fluid enclosure chamber 27 and the refrigerant from the refrigerant introduction chamber 26 are introduced to the outside. Both members (the lower housing 22 and the upper housing 23) are welded and joined so as not to leak. Furthermore, the fluid is charged into the working fluid enclosure 27 through an opening (fluid inlet) 28 provided in the top surface 23a of the upper housing 23. After the completion of the charging, a metal plug is inserted into the opening 28. A plug-shaped closing member 29 is inserted and welded to the upper housing 23 to close the opening 28 .

Further, Patent Document 1 below discloses an expansion valve provided with such a diaphragm device.

JP-A-8-226567

By the way, in the conventional expansion valve, as shown in FIG. 18 (which is an enlarged view of the portion C of FIG. 17), the groove between the plug 29 and the upper housing 23 is corroded by moisture (for example, condensed water). The factor 31 accumulates, causing corrosion of the welded portion 30 and leakage of the working fluid in the working fluid sealed chamber.

On the other hand, in order to prevent such corrosion, in the invention described in Patent Document 1, the periphery of the welded portion is filled with a corrosion-inhibiting material such as an adhesive to prevent water from accumulating in the groove portion (concave portion).

However, in the invention described in the document, the filling work of the corrosion inhibitor is required separately from the welding work, and there is a difficulty in increasing the number of manufacturing processes of the expansion valve (diaphragm device). In addition, corrosion inhibitors such as adhesives may deteriorate over time, and corrosive factors may enter through the deteriorated portions.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to obtain a new sealing structure capable of preventing corrosion of a working fluid sealing portion without increasing the number of manufacturing processes.

In order to solve the above problems and achieve the object, an expansion valve according to the present invention provides a valve body having a valve chamber communicating with an inflow passage for introducing refrigerant and an outflow passage for discharging refrigerant; A valve body that changes the flow rate of a refrigerant by moving back and forth with respect to a valve seat, a diaphragm device that drives the valve body, and a return passage that penetrates the valve body and allows passage of the refrigerant, The device comprises a lower housing, an upper housing that covers the upper surface of the lower housing, and a working fluid enclosing chamber that defines a refrigerant introduction chamber communicating with the return flow path between the lower housing and the lower housing and encloses the working fluid. A diaphragm disposed between the lower housing and the upper housing so as to be formed between the upper housing and a fluid injector formed at the top of the upper housing so as to inject the working fluid into the working fluid enclosure chamber. An expansion valve having an inlet and a closing member that is welded to the upper housing so as to cover the fluid inlet from above and closes the fluid inlet, wherein the top part has a truncated conical shape with no bottom and no lid. , and at least a portion of the top surface of the top portion outside the welded portion where joining with the closing member is performed is an inclined surface that slopes downward toward the outside.

In the expansion valve according to the present invention, the closing member is welded to the fluid inlet provided on the top surface of the upper housing to close the fluid inlet and seal the fluid-sealed chamber. The top of the lid member where Slope. In addition, "outside (outward, outside)" means a direction away from the central axis of the upper housing (fluid inlet) (the direction opposite to the direction toward the central axis).

Therefore, according to the present invention, corrosive factors such as water adhering to the outside of the welded portion flow outward (in a direction away from the welded portion) along the downwardly sloping inclined surface, and do not accumulate on the welded portion side. . This can prevent the welds from corroding.

Further, in the first aspect of the present invention, the closing member is configured by a cap-shaped member having a recess on the bottom surface in which the peripheral edge of the fluid inlet is accommodated.

Furthermore, in the first aspect, the steep slope portion is formed by raising the peripheral edge of the fluid inlet toward the center of the fluid inlet and is raised obliquely upward, or the steep slope portion is provided by raising the peripheral edge of the fluid inlet vertically upward. may be provided in the upper housing, and the steeply inclined portion may be fitted into the recess.

According to this aspect, when the cap-shaped closing member is placed over the top of the upper housing and joined, centering is performed by fitting the steeply inclined portion of the top of the upper housing into the concave portion of the closing member. In other words, it becomes easier to align the central axes of the blocking member and the upper housing (fluid inlet), preventing the blocking member from being displaced during joining, and enabling the blocking member to be attached to the upper housing quickly and accurately. becomes.

In a second aspect of the present invention, the closing member is a truncated conical cap-like member with a bottomless lid.

Furthermore, in this second aspect, the closing member may be configured by a conical cap-like member without a bottom. If the blocking member has such a shape without a flat top surface, the corrosive factors such as water droplets can be washed off along the peripheral surface (conical surface), so that the corrosive factors can be prevented from accumulating on the surface of the blocking member. It is also possible to prevent corrosion of the closing member itself.

Note that the above-mentioned "conical shape" does not mean only a strict cone with a pointed apex. Since it is possible, the "conical shape" referred to in the present application is a concept including such a shape.

Moreover, in the third aspect of the present invention, the closing member is configured by a flat plate member having at least a flat bottom surface.

Further, in the third aspect, a curved top surface portion that abuts on the bottom surface of the closing member by curving and protruding upward is formed on the peripheral edge portion of the fluid inlet, and the welded portion is positioned on this curved top surface portion. The upper housing and the closing member may be joined together.

This is to prevent dust and spatter generated during welding from entering the fluid-filled chamber. That is, if the welded portion has a sharp edge, dust and spatter are likely to be generated. Therefore, it is possible to avoid or suppress the generation of dust and spatter, and prevent foreign matter from entering the fluid sealed chamber.

Further, for the same reason, there is a steep slope in which the peripheral edge of the fluid inlet is raised obliquely upward toward the center of the fluid inlet, or a steep slope in which the peripheral edge of the fluid inlet is raised vertically upward. While either is provided in the upper housing, a groove for accommodating the steeply inclined portion is provided on the bottom side of the closing member, and the upper housing and the closing member are arranged so that the welded portion is positioned outside the groove and the steeply inclined portion. and may be joined together.

According to this aspect, since the steeply inclined portion is interposed between the fluid inlet and the welded portion, even if dust and spatter are generated (at the welded portion) during welding, The steep slope portion can prevent these from entering the fluid-sealed chamber from the fluid inlet.

Further, in the present invention, the planar shape of the closing member may be polygonal.

This is for facilitating attachment of the diaphragm device to the expansion valve. Specifically, as a structure for fixing the diaphragm device to the expansion valve, a male thread is formed on the outer peripheral surface of the lower end portion of the diaphragm device, and a female thread that engages with the male thread is formed on the upper surface of the valve body of the expansion valve to which the diaphragm device is attached. In some cases, a formed threaded structure is adopted, but in the case of such a mounting structure, if the blocking member fixed to the top of the top surface of the diaphragm device is polygonal (for example, six like a bolt head) square shape), and when screwing the diaphragm device into the valve body and tightening it, it is now possible to use a general-purpose tool (such as a general-purpose hexagon wrench) to tighten it. It is possible to save the trouble of preparing a machine (for example, a dedicated outer diameter gripping chuck).

Further, in the present invention, the blocking member can be a sphere (spherical member). As the sphere, a metal sphere having a diameter larger than that of the fluid inlet may be used.

Further, the diaphragm device according to the present invention has a characteristic working fluid sealing structure similar to the expansion valve according to the present invention.

Specifically, the diaphragm device includes a lower housing, an upper housing that covers the upper surface of the lower housing, and a lower housing that forms a working fluid enclosing chamber that encloses a working fluid between the upper housing and the upper housing. A diaphragm placed between the body and the upper housing, a fluid inlet formed at the top of the upper housing so that the working fluid can be injected into the working fluid chamber, and an upper part covering the fluid inlet from above. and a closing member that is welded to the housing and closes the fluid inlet, wherein the top portion has a truncated conical shape with no bottom and no lid, and the top surface of the top portion includes: At least the portion outside the welded portion where joining with the closing member is performed is made into an inclined surface that slopes downward toward the outside.

According to the present invention, corrosion of the working fluid sealing portion can be prevented without increasing the number of manufacturing steps.

Other objects, features and advantages of the present invention will become apparent from the following description of embodiments of the present invention based on the drawings. In addition, the same code|symbol shows the same or a corresponding part in each figure.

FIG. 1 is a vertical cross-sectional view showing an expansion valve (closed state) according to a first embodiment of the present invention. FIG. 2 is an enlarged longitudinal sectional view showing the top portion of the upper housing and the closing member (portion B in FIG. 1/before welding) of the expansion valve according to the first embodiment. FIG. 3 is an enlarged longitudinal sectional view showing the top portion of the upper housing and the closing member (portion B in FIG. 1/state after welding) of the expansion valve according to the first embodiment. FIG. 4 is a longitudinal sectional view similar to FIG. 2 showing a modification of the top portion of the upper housing of the expansion valve according to the first embodiment. FIG. 5 is a longitudinal sectional view similar to FIG. 2 showing a working fluid sealing structure according to a second embodiment of the present invention. FIG. 6 is a longitudinal sectional view showing an enlarged sealing structure (state after welding) according to the second embodiment. FIG. 7 is a vertical cross-sectional view similar to FIG. 5 showing a sealing structure according to a modification of the second embodiment. FIG. 8 is a longitudinal sectional view showing an enlarged sealing structure (before welding) according to a third embodiment of the present invention. FIG. 9 is a longitudinal sectional view showing an enlarged sealing structure (state after welding) according to the third embodiment. FIG. 10 is a vertical cross-sectional view similar to FIG. 8 showing a sealing structure (before welding) according to a modification of the third embodiment. FIG. 11 is a longitudinal sectional view similar to FIG. 8 showing a sealing structure (before welding) according to another modification of the third embodiment. FIG. 12 is a vertical cross-sectional view similar to FIG. 8 showing the sealing structure (before welding) according to the fourth embodiment of the present invention. FIG. 13 is a vertical cross-sectional view showing the sealing structure (state after welding) according to the fourth embodiment, similar to FIG. FIG. 14 is a plan view showing a closing member used in the sealing structure according to the fourth embodiment; FIG. 15 is a plan view showing a modification of the closing member used in the sealing structure according to the fourth embodiment. FIG. 16 is a vertical cross-sectional view similar to FIG. 9 showing the sealing structure (state after welding) according to the fifth embodiment of the present invention. FIG. 17 is a longitudinal sectional view showing an expansion valve (valve closed state) provided with a conventional working fluid sealing structure. FIG. 18 is a longitudinal sectional view showing an enlarged view of the conventional sealing structure (part C in FIG. 17).

[First embodiment]
An expansion valve according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 4. FIG. The feature of the present invention lies in the working fluid sealing structure, and the configuration and operation of each part of the diaphragm device and each part of the expansion valve other than the sealing structure are the same as those of the conventional diaphragm device and expansion valve. , the same reference numerals as those in FIG. 17 are attached, and detailed description thereof will be omitted, and the sealing structure unique to the present invention will be mainly described. Although FIG. 1 shows mutually orthogonal two-dimensional coordinates representing front-rear and left-right directions, the following description is based on these directions.

As shown in FIG. 1, an expansion valve 51 according to the first embodiment of the present invention includes a valve body 2 having a valve chamber 6 communicating with an inflow passage 3 for introducing refrigerant and an outflow passage 4 for discharging refrigerant. , the flow rate of the refrigerant is changed by moving back and forth (up and down) with respect to the valve seat 7 between a closed state in which the valve is seated on the valve seat 7 provided in the valve chamber 6 and an open state in which the valve is separated from the valve seat 7. a biasing member (compression coil spring) 12 that biases the valve body 8 toward the valve seat 7 via the valve body support member 11 and presses the valve body 8 against the lower end of the operating rod 9; An operating rod 9 that moves the valve body 8 in the valve opening direction (downward) against the biasing force of the biasing member 12 , and is fixed to the upper surface of the valve body 2 and drives the valve body 8 via the operating rod 9 . It has a diaphragm device 61 and a return flow path 5 that passes through the valve body 2 and allows passage of the refrigerant.

The operating rod 9 is disposed inside the valve body 2 so as to extend in the vertical direction (vertical direction). It is brought into contact with the valve body 8 . The return channel 5 penetrates the upper portion of the valve body 2 horizontally (in the left-right direction), and the refrigerant sent from the evaporator 44 to the compressor 41 passes through the channel 5 . Refrigerant sent from the condenser 42 flows into the inflow passage 3 via the receiver tank 43 , and this refrigerant passes through the valve chamber 6 and is delivered from the outflow passage 4 to the evaporator 44 .

The diaphragm device 61 has a dish-shaped lower housing 22 as a housing of the device 61, and a lid-shaped upper housing 52 covering the upper surface of the lower housing 22. The lower housing 22 and the upper housing 52 A diaphragm 24 is sandwiched between them. The internal space above the diaphragm 24 (between the diaphragm 24 and the upper housing 52) is used as a working fluid enclosing chamber 27 for enclosing the working fluid, and below the diaphragm 24 (between the diaphragm 24 and the lower housing 22). The internal space between the two is defined as a coolant introduction chamber 26 for introducing a coolant. An opening 10 that communicates the coolant introduction chamber 26 and the return flow path 5 is provided in the center of the bottom surface of the lower housing 22 .

The top portion 52a of the upper housing 52 has a truncated conical shape with no bottom and no lid, or in other words, a vertical cross-sectional shape of a V-shape, and the top surface of the top portion 52a is directed outward, that is, at the center. The surface is inclined downward in the direction away from the axis A.

A fluid injection port 53 is provided at the central axis of the top portion 52a. This fluid injection port 53 is an opening for injecting the working fluid into the working fluid sealed chamber 27 . The fluid injection port 53 is not a plug-shaped member 29 as in the conventional (FIG. 17), but is covered with the top portion 52a of the upper housing 52 having a concave portion 54a on the bottom and provided with the fluid injection port 53. It is closed by a cap-shaped closing member 54 that is attached in a manner as described above. The closing member 54 is joined to the upper housing 52 by covering the top portion 52a of the upper housing 52 with the closing member 54 so that the top surface of the top portion 52a is brought into contact with the inner peripheral surface of the concave portion 54a of the closing member 54. , the contact surfaces of both members 52 and 54 are melted and joined by projection welding. Reference numeral 30 in FIG. 3 indicates the welded portion (welded portion).

In this embodiment and each embodiment described later, projection welding is used as a method of joining the closing member to the upper housing 52, but the joining method is not necessarily limited to this method, and other welding methods or methods other than welding are used. A joining method is also possible.

Conventionally (see FIGS. 17 and 18), the top portion (particularly the portion near the fluid inlet 28) 23a of the upper housing 23 has an inverted truncated cone shape (vertical cross-sectional inverted V shape), but in the present embodiment, this is the case. is formed into a truncated cone shape (vertical cross-section shape) as described above, and the fluid injection port 53 is closed by a cap-like member 54 attached so as to cover the top portion 52a.

Therefore, in the present embodiment, the welded portion 30 is positioned above the gap 32 between the upper housing 52 and the closing member 54, contrary to the conventional technique (as shown in FIG. 32), but the gap 32 faces obliquely downward. Therefore, according to the present embodiment, corrosive factors are less likely to enter the welded portion 30, and the corrosive factors flow outward (in a direction away from the welded portion 30) along the downwardly sloped surface. Furthermore, the structure (the shape of the upper housing and the sealing member) itself according to the present embodiment does not deteriorate due to long-term use unlike corrosion inhibitors such as adhesives. Thus, according to this embodiment (the present invention and other embodiments are also applicable), corrosion of the welded portion 30 can be effectively prevented.

FIG. 4 shows a modification of the sealing structure of this embodiment. As shown in the figure, in this modification, the edge of the top portion 52a of the upper housing forming the fluid inlet 53 is provided with a steeply inclined portion 52b that is raised obliquely upward toward the central axis A. 52b is fitted into the bottom recessed portion 54a of the closing member 54. As shown in FIG.

According to such a structure, the steeply inclined portion 52b can provide a centering function, that is, a function of aligning the central axis A of the upper housing 52 with the central axis of the closing member 54. It is possible to prevent the closing member 54 from being displaced when it is joined to the upper housing 52, and to join the closing member 54 to the upper housing 52 quickly and accurately to more reliably block the fluid inlet 53. It becomes possible.

The working fluid sealing structure, that is, the top portion 52a (fluid inlet 53) of the upper housing 52 and the closing member 54 can take various forms other than the present embodiment. These will be described below as second to fifth embodiments of the present invention.

[Second embodiment]
5 to 6 show a sealing structure according to a second embodiment of the invention. As shown in the figure, the sealing structure according to the second embodiment of the present invention is provided with a truncated conical (shade-like) closing member 55 with a bottomless lid (without a bottom and with a top surface). . The top portion 52a of the upper housing 52 has a cap shape like the closing member 55, and has a fluid inlet 53 in the center.

Then, the closing member 55 is put on the top portion 52a so as to close the fluid inlet 53, and the closing member 55 and the upper housing top portion 52a are welded. Note that the joint (welded portion) is indicated by reference numeral 30 in FIG.

Moreover, although the closing member 55 of the present embodiment has the flat top surface portion 55a, it is possible to have a structure without the flat top surface portion 55a. Specifically, as shown in FIG. 7, the entire closing member 56 may have a mountain shape, in other words, a bottomless (bottomless) conical shape. With such a shape, the entire upper surface of the closing member 56 becomes a downwardly sloping surface. corrosion can also be prevented.

[Third embodiment]
As shown in FIGS. 8 and 9, the sealing structure according to the third embodiment of the present invention includes a flat plate (disk)-like blocking member 57, and the blocking member 57 is positioned above the fluid inlet 53 so as to cover the fluid inlet 53. The upper edge of the fluid injection port 53 (the edge of the upper housing 52 on the side of the fluid injection port 53) and the bottom surface of the closing member 57 are welded together (see welded portion 30). , the fluid inlet 53 may be closed by such a closing member 57 .

Furthermore, if the welded portion has a sharp edge, dust and spatter are likely to be generated during projection welding, and foreign matter enters the fluid-sealed chamber 27 (see FIG. 1) from the fluid inlet 53 when the closing member 57 is welded. There is a risk of 10 and 11 solves such a problem, in which the upper edge of the fluid injection port 53, which is brought into contact with the closing member 57 and joined, is rounded and angular. It has no sharp edges.

More specifically, in the example shown in FIG. 10 , the upper edge portion is shaved to form a curved surface (curved top surface portion according to the present invention) 52 c so that the curved surface 52 c contacts the bottom surface of the closing member 57 . In the example shown in FIG. 11, the edge 52d on the side of the fluid inlet of the upper housing 52 forming the fluid inlet 53 is bent downward to curve the upper surface. The surface portion 52c is brought into contact with the bottom surface of the closing member 57. As shown in FIG.

In any modification, the flat bottom surface of the closing member 57 contacts the curved top surface portion 52c of the upper housing 52, and this portion can be used as a welded portion. It is possible to prevent foreign matter from entering the fluid-sealed chamber 27 by suppressing it.

[Fourth embodiment]
As shown in FIGS. 12 to 14, in the sealing structure according to the fourth embodiment of the present invention, a disk-shaped blocking member 58 is placed on the top portion 52a of the upper housing 52 to block the fluid inlet 53. However, the top portion 52a of the upper housing 52 is provided with a steeply inclined portion 52e in which the periphery of the fluid injection port 53 is raised obliquely upward toward the center of the fluid injection port 53, and the bottom surface of the closing member 58 is provided with A groove portion 58a that accommodates the steeply inclined portion 52e is formed, and the upper housing 52 and the closing member 58 are joined together so that the welding portion 30 (see FIG. 13) is positioned outside the grooved portion 58a and the steeply inclined portion 52e. .

According to such a structure, since the steeply inclined portion 52e is interposed between the fluid inlet 53 and the welded portion 30, even if dust and spatter are generated at the welded portion 30, these can be prevented from entering the fluid-sealed chamber 27 from the fluid inlet 53 by the steeply inclined portion 52e.

FIG. 15 shows a closing member 59 according to a modification of the closing member 58 of this embodiment. You may make it have. As described above, a threaded structure may be employed as a method for fixing the diaphragm device 21 to the expansion valve 61 (valve body 2). This is because it is possible to perform the tightening operation with a general-purpose tool such as a hexagonal wrench without using it.

In the first embodiment and its modifications (FIGS. 1 to 4) and the third embodiment and its modifications (FIGS. 8 to 11), the blocking members 54 and 57 are also polygonal (for example, hexagonal). ).

[Fifth embodiment]
As shown in FIG. 16, the sealing structure according to the fifth embodiment of the present invention includes a spherical member 60 as a blocking member that blocks the fluid inlet 53 of the upper housing top portion 52a. As the spherical member 60, a metal ball having a diameter larger than that of the fluid inlet 53 is used, and the contact portion between the upper edge of the fluid inlet 53 and the spherical member 60 is melted by projection welding as indicated by reference numeral 30. should be joined together.

Even with such a structure, since the top surface of the top portion 52a outside the welded portion 30 is a sloped surface with a downward slope, corrosive factors do not accumulate and the welded portion 30 can be prevented from being corroded.

Although the embodiments of the present invention have been described above, it is obvious to those skilled in the art that the present invention is not limited to these, and that various modifications can be made within the scope of the claims. .

For example, since the feature of the present invention resides in the sealing structure for the working fluid, the configuration of each part of the diaphragm device and each part of the expansion valve other than the sealing structure is similar to that of the embodiment (FIG. 1) and the prior art (FIG. 17). may be different from those described in the description of the expansion valve.

A central axis B, C working fluid sealing part (top part of upper housing)
Reference Signs List 1, 51 expansion valve 2 valve body 3 inflow passage 4 outflow passage 5 return passage 6 valve chamber 7 valve seat 8 valve body 9 operating rod 10 opening 11 valve body supporting member 12 biasing member (compression coil spring)
21, 61 diaphragm device 22 lower housing 23, 52 upper housing 23a, 52a top portion of upper housing 24 diaphragm 25 operating rod receiving member 26 refrigerant introduction chamber 27 working fluid sealing chamber 28, 53 fluid inlet 29, 54, 55, 56, 57, 58, 59, 60 Closing member 30 Welded portion 31 Corrosion factor 32 Gap between upper housing and closing member 41 Compressor
42 Condenser (condenser)
43 receiver tank 44 evaporator (evaporator)
52b, 52e Steep slope 52c Curved surface 52d Fluid inlet side edge of upper housing 54a Recess 55a Top surface of closing member 58a Groove

Claims (11)

a valve body having a valve chamber that communicates with an inflow passage for introducing the refrigerant and an outflow passage for discharging the refrigerant;
a valve body that changes the flow rate of the refrigerant by moving back and forth with respect to a valve seat provided in the valve chamber;
a diaphragm device that drives the valve body;
a return passage that penetrates the valve body and allows passage of the refrigerant,
The diaphragm device
a lower housing;
an upper housing that covers the upper surface of the lower housing;
The lower housing and the upper housing form a coolant introduction chamber communicating with the return flow path between the lower housing and a working fluid enclosing chamber for enclosing a working fluid between the lower housing and the upper housing. a diaphragm arranged between the upper housing;
a fluid injection port formed at the top of the upper housing so as to inject the working fluid into the working fluid enclosure;
a closing member that is welded to the upper housing so as to cover the fluid inlet from above and closes the fluid inlet, wherein the expansion valve comprises:
The apex has a truncated conical shape with no bottom and no lid,
An expansion valve, wherein at least a portion of the top surface of the top portion outside a welded portion where joining with the closing member is performed is an inclined surface that slopes downward toward the outside. 2. The expansion valve according to claim 1, wherein the closing member is a cap-shaped member having a bottom surface with a recess in which the peripheral edge of the fluid inlet is accommodated. The upper housing is provided with a steeply inclined portion in which the peripheral edge of the fluid inlet is raised obliquely upward toward the center of the fluid inlet, or the peripheral edge of the fluid inlet is raised vertically upward,
3. The expansion valve according to claim 2, wherein said steeply inclined portion is fitted into said recess. 2. The expansion valve according to claim 1, wherein the closing member is a truncated conical cap-like member with a bottomless lid. 2. The expansion valve according to claim 1, wherein the closure member is a bottomless conical cap member. The expansion valve according to claim 1, wherein the closing member is a flat plate member having at least a flat bottom surface. forming a curved top surface portion on the periphery of the fluid inlet, the curved top surface portion being curved and projecting upward to abut on the bottom surface of the closing member;
7. The expansion valve according to claim 6, wherein the upper housing and the closing member are joined together so that the welded portion is positioned on the curved top surface portion. While the upper housing is provided with a steeply inclined portion in which the peripheral edge of the fluid inlet is raised obliquely upward toward the center of the fluid inlet, or the peripheral edge of the fluid inlet is raised vertically upward,
A groove portion for accommodating the steep slope portion is provided on the bottom surface side of the closing member,
7. The expansion valve according to claim 6, wherein the upper housing and the closing member are joined together so that the welded portion is located outside the groove and the steeply inclined portion. The expansion valve according to any one of claims 1 to 3 and 6 to 8, wherein the planar shape of the closing member is polygonal. The expansion valve according to claim 1, wherein the closing member is a sphere. a lower housing;
an upper housing that covers the upper surface of the lower housing;
a diaphragm disposed between the lower housing and the upper housing so as to form a working fluid sealing chamber that seals a working fluid between the upper housing and the lower housing;
a fluid injection port formed at the top of the upper housing so as to inject the working fluid into the working fluid enclosure;
a closing member that is welded to the upper housing so as to cover the fluid inlet from above and closes the fluid inlet, wherein
The apex has a truncated conical shape with no bottom and no lid,
A diaphragm device, wherein at least a portion of the top surface of the top portion outside a welded portion where joining with the closing member is performed is an inclined surface that slopes downward toward the outside.

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