JP2024068727A - Expansion valve - Google Patents

Abstract

To provide an expansion valve capable of suppressing local deformation of a diaphragm while suppressing a degree of increase of manufacturing costs.SOLUTION: An expansion valve includes: a valve body including a refrigerant flow passage and a recessed portion communicated to the refrigerant passage via a communication hole; a power element including a case, a diaphragm mounted on the case, and a stopper member kept into contact with the diaphragm in the case and mounted on the recessed portion; an operation rod kept into contact with the stopper member at one end and movable to the valve body; and a barrier member disposed between the stopper member and an opposite wall opposed to the stopper member in the recessed portion. The barrier member is formed into a hollow cylindrical shape with an elastically deformable material, disposed in a manner of surrounding the communication hole, and at least partially elastically deformed in a state of being assembled in the valve body, and the barrier member is closely kept into contact with the stopper member and the opposite wall by elastic force generated by the elastic deformation.SELECTED DRAWING: Figure 1

Description

The present invention relates to an expansion valve.

Conventionally, for example, in refrigeration cycles used in air conditioners installed in automobiles, a temperature-sensing thermal expansion valve is used to adjust the amount of refrigerant passing through depending on the temperature. Such thermal expansion valves use a power element that drives the valve body using the pressure of the enclosed working gas.

A typical power element includes a diaphragm, an upper cover member that forms a pressure actuated chamber in which a working gas is sealed between the diaphragm and the upper cover member, a receiving member that has a through hole in the center and is positioned on the opposite side of the diaphragm to the upper cover member, and a stopper member that is positioned in a fluid inflow chamber formed between the diaphragm and the receiving member and is connected to an actuating rod that drives the valve body. The diaphragm is formed from a thin, flexible metal plate.

If the temperature of the refrigerant flowing into the fluid inlet chamber is low, the refrigerant removes heat from the working gas in the pressure actuated chamber, causing the working gas to contract. If the temperature of the refrigerant is high, the refrigerant imparts heat to the working gas in the pressure actuated chamber, causing the working gas to expand. The actuating rod opens and closes the valve body depending on the amount of deformation of the diaphragm caused by the contraction/expansion of the working gas.

In general refrigeration cycles, a strainer is provided in the main flow path of the refrigeration cycle to capture foreign matter that has become mixed in with the refrigerant. However, minute foreign matter can pass through the strainer and enter the power element. In such cases, foreign matter may get between the receiving member and the diaphragm, which may cause local deformation of the diaphragm. One solution is to give the strainer the ability to capture even the smallest foreign matter, but this may increase pressure loss in the strainer and reduce the efficiency of transporting the refrigerant in the refrigeration cycle.

In response to this, Patent Document 1 discloses an expansion valve in which a filter is provided at the entrance of the fluid inlet chamber of the power element. The expansion valve disclosed in Patent Document 1 has a holder in which an actuating rod is disposed. The holder has a communication hole that connects the fluid inlet chamber with a flow path formed in the valve body, and a filter is provided in the communication hole. The filter is insert molded into the holder. In this way, by providing a filter at the entrance of the inlet flow path in addition to the filter provided in the main flow path, it is possible to prevent the pressure loss in the main flow path of the refrigeration cycle from increasing, even if the filter is given the ability to capture even the smallest foreign objects.

JP 2006-112749 A

However, the expansion valve disclosed in Patent Document 1 has a holder and is configured such that a filter is insert-molded into the holder, making the expansion valve structure complex and resulting in increased manufacturing costs for the expansion valve.

The present invention aims to provide an expansion valve that can suppress local deformation of the diaphragm while minimizing the increase in manufacturing costs.

In order to achieve the above object, the expansion valve according to the present invention comprises:
a valve body including a refrigerant flow path and a recess communicating with the refrigerant flow path via a communication hole;
a power element including a case, a diaphragm attached to the case, and a stopper member that abuts against the diaphragm inside the case, the power element being attached to the recess;
an actuating rod that is inserted into the communication hole and has one end in contact with the stopper member;
a barrier member disposed between the stopper member and an opposing wall facing the stopper member in the recess,
The barrier member is formed into a hollow cylindrical shape from an elastically deformable material and is arranged to surround the communicating hole, and at least a portion of the barrier member elastically deforms when assembled to the valve body, and the elastic force generated by the elastic deformation causes the barrier member to adhere closely to the stopper member and the opposing wall.

The present invention provides an expansion valve that can suppress local deformation of the diaphragm while minimizing the increase in manufacturing costs.

FIG. 1 is a schematic cross-sectional view showing an example in which an expansion valve according to a first embodiment is applied to a refrigerant circulation system. FIG. 2 is a schematic cross-sectional view showing the expansion valve according to the first embodiment. FIG. 3 is a perspective view of a barrier member. FIG. 4 is an enlarged cross-sectional view showing the periphery of a barrier member according to a first modified example. FIG. 5 is a perspective view of a barrier member according to a second modified example. FIG. 6 is a schematic cross-sectional view showing an expansion valve according to the second embodiment. FIG. 7 is a schematic cross-sectional view showing an expansion valve according to the second embodiment. FIG. 8 is a schematic cross-sectional view showing an expansion valve according to the third embodiment. FIG. 9 is a schematic cross-sectional view showing an expansion valve according to the fourth embodiment. FIG. 10 is a schematic cross-sectional view showing an expansion valve according to the fifth embodiment. FIG. 11 is a schematic cross-sectional view showing an expansion valve according to the sixth embodiment. FIG. 12 is a cross-sectional view of a barrier member according to the seventh embodiment.

The following describes an embodiment of the present invention with reference to the drawings.

(Direction definition)
In this specification, the direction from the valve disc 3 to the actuating rod 5 is defined as the "upward direction", and the direction from the actuating rod 5 to the valve disc 3 is defined as the "downward direction". Therefore, in this specification, the direction from the valve disc 3 to the actuating rod 5 is called the "upward direction", regardless of the attitude of the expansion valve 1. Also, "cylinder" includes hollow cylinders and solid cylinders.

First Embodiment
An overview of an expansion valve 1 including a power element in a first embodiment will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is a schematic cross-sectional view showing an example in which the expansion valve 1 in this embodiment is applied to a refrigerant circulation system 100. Fig. 1 shows the expansion valve 1 in a maximum valve open state among communication states described later. Fig. 2 is a schematic cross-sectional view showing the expansion valve 1 in a non-communication state described later. In this embodiment, the expansion valve 1 is fluidly connected to a compressor 101, a condenser 102, and an evaporator 104. The center line of the operating rod 5 of the expansion valve 1 is set as an axis L.

In Figures 1 and 2, the expansion valve 1 comprises a valve body 2 having a valve chamber VC, a valve body 3, a biasing device 4, an actuating rod 5, and a power element 8.

The valve body 2 includes a valve chamber VC, a first flow path 21, a second flow path 22, an intermediate chamber 221, and a return flow path (also called a refrigerant flow path) 23. The first flow path 21 is a supply side flow path, and refrigerant is supplied to the valve chamber VC via the supply side flow path. The second flow path 22 is a discharge side flow path, and the fluid in the valve chamber VC is discharged outside the expansion valve via the flow hole 27, the intermediate chamber 221, and the discharge side flow path.

The first flow path 21 and the valve chamber VC are connected by a connection path 21a that has a smaller diameter than the first flow path 21. The valve chamber VC and the intermediate chamber 221 are connected via the valve seat 20 and the flow hole 27.

The actuating rod insertion hole 28 formed above the intermediate chamber 221 has the function of guiding the actuating rod 5, and the annular recess 29 formed above the actuating rod insertion hole 28 has the function of accommodating the ring spring 6. The ring spring 6 applies a predetermined biasing force by abutting multiple spring pieces against the outer periphery of the actuating rod 5.

The valve element 3 is disposed in the valve chamber VC. As shown in FIG. 2, when the valve element 3 is seated on the valve seat 20 of the valve body 2, the flow of refrigerant through the flow hole 27 is restricted. This state is called a non-communicating state. However, even when the valve element 3 is seated on the valve seat 20, a restricted amount of refrigerant may flow. On the other hand, when the valve element 3 is separated from the valve seat 20, the flow of refrigerant passing through the flow hole 27 increases. This state is called a communicating state. The expansion valve 1 shown in FIG. 1 is in a maximum open state in which the valve element 3 is fully open in the communicating state.

The actuating rod 5 is inserted through the flow hole 27 with a specified gap. The lower end of the actuating rod 5 is in contact with the upper surface of the valve body 3. The upper end of the actuating rod 5 is fitted into the fitting hole 84c of the stopper member 84 described later.

The actuating rod 5 can press the valve body 3 in the valve opening direction against the biasing force of the biasing device 4. When the actuating rod 5 moves downward, the valve body 3 moves away from the valve seat 20, and the expansion valve 1 opens.

In Figures 1 and 2, the biasing device 4 has a coil spring 41 made of a wire material with a circular cross section wound in a spiral shape, a valve body support 42, and a spring receiving member 43.

The valve body support 42 is attached to the upper end of the coil spring 41, and the spherical valve body 3 is welded to its upper surface, so that the two are integrated.

The spring bearing member 43 that supports the lower end of the coil spring 41 can be screwed into the valve body 2 and has the functions of sealing the valve chamber VC and adjusting the biasing force of the coil spring 41.

Next, the power element 8 will be described. The power element 8 has a plug 81, an upper cover member 82, a diaphragm 83, a receiving member 86, and a stopper member 84. The upper cover member 82 and the receiving member 86 form a case. Again, the upper cover member 82 side is the upper side, and the receiving member 86 side is the lower side.

The top cover member 82 is formed, for example, by pressing a metal plate. The top cover member 82 has an annular outer flange portion 82a and a dome-shaped central portion 82b that is connected to the inner circumference of the outer flange portion 82a. An opening 82c is formed in the center of the central portion 82b, and can be sealed with a plug 81.

The receiving member 86 facing the upper cover member 82 is formed, for example, by pressing a metal plate. The receiving member 86 has a first flange portion 86a having an outer diameter substantially the same as the outer diameter of the outer flange portion 82a, a hollow first cylindrical portion 86b connected to the inner circumference of the first flange portion 86a and facing downward, an annular second flange portion 86c connected to the lower end of the first cylindrical portion 86b, and a hollow second cylindrical portion 86d connected to the inner circumference of the second flange portion 86c. A male thread 86e is formed on the outer circumference of the second cylindrical portion 86d.

At the upper end of the valve body 2, a cylindrical recess 2a is formed with a bottom wall (also called an opposing wall) 2d that faces the stopper member 84, and on the inner circumference of the recess 2a, a female thread 2c that can be screwed into the male thread 86e is formed.

The diaphragm 83, which is disposed between the top cover member 82 and the receiving member 86, is made of a thin, flexible metal (e.g., SUS) plate material and has an outer diameter approximately the same as the outer diameters of the top cover member 82 and the receiving member 86.

The stopper member 84 has a solid cylindrical body 84a, a disk portion 84b connected to the upper end of the body 84a and extending in the radial direction, and a blind hole-shaped fitting hole 84c formed in the center of the lower surface of the body 84a. The disk portion 84b is in contact with the lower surface of the center of the diaphragm 83.

A barrier member 87 is disposed between the underside of the stopper member 84 and the bottom wall 2d of the recess 2a, surrounding the communication hole 2b, which will be described later.

3 is a perspective view of the barrier member 87. The barrier member 87 is formed in a hollow cylindrical shape from an elastically deformable resin material, and is composed of an annular small diameter portion 87a, a hollow conical portion (also called a deformation portion, the same applies below) 87b that expands in diameter as it goes downward, and an annular large diameter portion 87c that is larger in diameter than the small diameter portion 87a. The small diameter portion 87a extends radially inward from the hollow conical portion 87b, and the large diameter portion 87c extends radially outward from the hollow conical portion 87b. It is preferable that the thickness of the barrier member 87 is uniform. The barrier member 87 may be formed from a material that does not allow foreign matter to pass through but allows liquefied refrigerant to pass through. This material is, for example, a mesh or sponge material that does not allow foreign matter to pass through but allows liquefied refrigerant to pass through. The upper end shape of the barrier member 87 does not have to match the lower end shape of the stopper member 84.

In this embodiment, the dimensions of the barrier member 87 are preferably set so that the inner diameter of the small diameter portion 87a is larger than the outer diameter of the actuation rod 5 in both the connected and disconnected states, thereby ensuring the elastic deformation function of the barrier member 87. Also, the dimensions of the barrier member 87 are preferably set so that the outer diameter of the large diameter portion 87c is equal to the inner diameter of the recess 2a in the disconnected state, thereby restricting the movement of the barrier member 87 in the direction intersecting the axis L within the recess 2a when the barrier member 87 is installed within the recess 2a.

When the expansion valve 1 is in a non-communicating state, the barrier member 87 is compressed between the stopper member 84 and the bottom wall 2d of the recess 2a. The barrier member 87 comes into contact with the lower end of the stopper member and the bottom wall 2d of the recess 2a due to the restoring force generated by this compression.

Furthermore, the barrier member 87 is compressed and deformed in the process in which the expansion valve 1 changes from the non-communicating state as shown in FIG. 2 to the maximum open state as shown in FIG. 1. In this embodiment, the barrier member 87 is deformed, for example, at the small diameter portion 87a and the hollow cone portion 87b. Specifically, the small diameter portion 87a is deformed so as to be displaced radially inward. Note that the deformation of the barrier member 87 occurring between FIG. 1 and FIG. 2 is exaggerated for ease of understanding. Also, the deformation of the barrier member 87 occurring between FIG. 1 and FIG. 2 is one example. The deformation of the barrier member occurring between the non-communicating state and the maximum open state of the expansion valve 1 occurs according to the dimensions of the barrier member 87, etc. For example, the barrier member 87 may be deformed at the hollow cone portion 87b and the large diameter portion 87c so that the large diameter portion 87c is displaced radially outward.

Next, the assembly procedure for the power element 8 will be described. While placing the stopper member 84 between the diaphragm 83 and the receiving member 86, the outer flange portion 82a of the upper cover member 82, the outer periphery of the diaphragm 83, and the first flange portion 86a of the receiving member 86 are overlapped in this order and pressed in the axial direction, while the outer periphery is welded by, for example, TIG welding, laser welding, plasma welding, etc., all around to weld them together.

Next, the working gas is injected into the space surrounded by the top cover member 82 and the diaphragm 83 (called the pressure actuated chamber PO) through the opening 82c formed in the top cover member 82, and then the opening 82c is sealed with the plug 81, and the plug 81 is fixed to the top cover member 82, for example, by projection welding.

At this time, the working gas sealed in the pressure actuated chamber PO pressurizes the center of the diaphragm 83 in such a way that it juts out toward the receiving member 86, so that the center of the diaphragm 83 abuts and is supported by the upper surface of the stopper member 84, which is located in the lower space (refrigerant inlet chamber) LS surrounded by the diaphragm 83 and the receiving member 86.

Before assembling the power element 8 assembled as described above to the valve body 2, the barrier member 87 is attached to the valve body 2. Specifically, the barrier member 87 is placed in the recess 2a with the large diameter portion 87c abutting the bottom wall 2d. At this time, the outer periphery of the large diameter portion 87c abuts the inner periphery of the side wall of the recess 2a, restricting the movement of the barrier member 87 in the direction perpendicular to the axis. The barrier member 87 can be easily installed by hand without using tools, and can be retrofitted to an existing expansion valve 1 without design changes. However, the barrier member 87 may also be fixed to the bottom wall 2d using adhesive, screws, etc.

Then, the male thread 86e formed on the outer periphery of the lower end of the second cylindrical portion 86d of the power element 8 is screwed into the female thread 2c formed on the inner periphery of the recess 2a of the valve body 2, and as the male thread 86e is threaded into the female thread 2c, the lower surface of the second flange portion 86c of the receiving member 86 abuts against the upper end surface of the valve body 2. This allows the power element 8 to be fixed to the valve body 2.

At this time, the upper surface of the small diameter portion 87a abuts against the lower surface of the stopper member 84, and the lower surface of the large diameter portion 87c abuts against the upper surface of the bottom wall 2d, so that the entire circumferences of the small diameter portion 87a and the large diameter portion 87c are in close contact with each other, and mainly the hollow cone portion 87b of the barrier member 87 elastically deforms. The elastic deformation force generated at this time urges the upper surface of the small diameter portion 87a toward the lower surface of the stopper member 84, and urges the lower surface of the large diameter portion 87c toward the upper surface of the bottom wall 2d. Note that, in the assembled state, the lower end of the second cylindrical portion 86d may press the upper end surface of the large diameter portion 87c of the barrier member 87.

As shown in FIG. 1, in the maximum open state, the barrier member 87 is pressed by the stopper member 84, and is deformed so that the upper end of the barrier member 87 moves radially inward. Alternatively, depending on the shape of the barrier member 87 and the dimensions of each part, in this embodiment, depending on the dimensions of the small diameter portion 87a, the hollow cone portion 87b, and the large diameter portion 87c, in the maximum open state, the small diameter portion 87a may be deformed so as to bend downward from the upper end of the hollow cone portion 87b by being pressed by the stopper member 84.

A packing PK is interposed between the assembled power element 8 and the valve body 2, sealing the space in the recess 2a that is connected to the lower space LS, preventing refrigerant leakage from the recess 2a. In this state, the lower space LS of the power element 8 is connected to the return flow path 23 through the communication hole 2b formed between the bottom wall 2d of the recess 2a and the return flow path 23. The operating rod 5 is then inserted from below the valve body 2, and its upper end passes through the communication hole 2b and the small diameter portion 87a of the barrier member 87 and is fitted into the fitting hole 84c of the stopper member 84. The expansion valve 1 is then completed by incorporating the valve body 3 and the biasing device 4.

(Expansion valve operation)
An example of the operation of the expansion valve 1 will be described with reference to Figures 1 and 2. The refrigerant pressurized by the compressor 101 is liquefied by the condenser 102 and sent to the expansion valve 1. The refrigerant adiabatically expanded by the expansion valve 1 is sent to the evaporator 104, where it is heat exchanged with the air flowing around the evaporator. The refrigerant returning from the evaporator 104 is returned to the compressor 101 side through the expansion valve 1 (more specifically, the return flow path 23). At this time, by passing through the evaporator 104, the fluid pressure in the second flow path 22 becomes greater than the fluid pressure in the return flow path 23.

The expansion valve 1 is supplied with high-pressure refrigerant from the condenser 102. More specifically, the high-pressure refrigerant from the condenser 102 is supplied to the valve chamber VC via the first flow path 21.

When the valve body 3 is seated on the valve seat 20 (in a non-communicating state) as shown in FIG. 2, the flow rate of the refrigerant sent from the valve chamber VC through the flow hole 27, the intermediate chamber 221, and the second flow path 22 to the evaporator 104 is restricted. On the other hand, when the valve body 3 is separated from the valve seat 20 (in a communicating state) as shown in FIG. 1, the flow rate of the refrigerant sent from the valve chamber VC through the flow hole 27, the intermediate chamber 221, and the second flow path 22 to the evaporator 104 increases. The expansion valve 1 is switched between the closed state and the open state by the operating rod 5 connected to the power element 8 via the stopper member 84.

1 and 2, the power element 8 has a pressure actuated chamber PO and a lower space LS separated by a diaphragm 83. When the working gas in the pressure actuated chamber PO is liquefied, the diaphragm 83 rises, and the stopper member 84 and the working rod 5 move upward in response to the biasing force of the coil spring 41. When the stopper member 84 rises, the elastic deformation of the barrier member 87 decreases, but the elastic deformation is not completely restored, so the upper surface of the small diameter portion 87a is biased toward the lower surface of the stopper member 84, and the lower surface of the large diameter portion 87c remains biased toward the upper surface of the bottom wall 2d. However, the vaporized refrigerant may be able to pass through the gap between the barrier member 87 and the stopper member 84 or the bottom wall 2d.

On the other hand, when the liquefied working gas vaporizes, the diaphragm 83 and the stopper member 84 are pressed downward, and the working rod 5 moves downward. As the stopper member 84 descends, the amount of elastic deformation of the barrier member 87 increases, so that the descent of the stopper member 84 is prevented from being impeded. The barrier member 87 has a hollow cone portion 87b, so that its reduced diameter end (here, the upper end) can elastically deform so as to further reduce in diameter. As is clear, the upper surface of the small diameter portion 87a is biased toward the lower surface of the stopper member 84, and the lower surface of the large diameter portion 87c remains biased toward the upper surface of the bottom wall 2d. In this way, the expansion valve 1 is switched between the open state and the closed state.

Furthermore, the vaporized refrigerant can pass from the inside of the barrier member 87 through the gap between the stopper member 84 or the bottom wall 2d to the lower space LS of the power element 8. Therefore, the volume of the working gas in the pressure actuated chamber PO changes depending on the temperature and pressure of the refrigerant flowing through the return flow path 23, and the actuating rod 5 is driven. In other words, in the expansion valve 1 shown in Figures 1 and 2, the amount of refrigerant supplied from the expansion valve 1 to the evaporator 104 is automatically adjusted depending on the temperature and pressure of the refrigerant returning from the evaporator 104 to the expansion valve 1. Note that even if the vaporized refrigerant is blocked by the barrier member 87, heat is transferred to the pressure actuated chamber PO via the stopper member 84, so the operation of the power element 8 is not hindered.

According to this embodiment, regardless of the axial position of the stopper member 84, the upper end of the barrier member 87 abuts against the stopper member 84, and the lower end of the barrier member 87 abuts against the bottom wall 2d. Therefore, even if foreign matter is mixed in the refrigerant, the foreign matter cannot pass from the inside to the outside of the barrier member 87. Therefore, the foreign matter in the refrigerant cannot reach the diaphragm 83, so that the foreign matter can be prevented from being caught in the diaphragm 83. As a result, local deformation of the diaphragm can be prevented. Furthermore, since the barrier member 87, which has a relatively simple shape, is arranged between the stopper member 84 and the bottom wall 2d, the degree of increase in the manufacturing cost of the expansion valve 1 can be reduced. It is preferable to make the diameter of the barrier member 87 as large as possible, since this has less effect on the operation of the power element 8.

(First Modification)
Fig. 4 is an enlarged cross-sectional view of the barrier member 87A and its periphery according to the first modified example. In this modified example, only the configurations of the valve body 2A and the barrier member 87A are different from those of the first embodiment. The other configurations are the same as those of the first embodiment, and therefore will not be described again. Fig. 4 shows the expansion valve 1 in the maximum valve open state.

In the valve body 2A, only the shape of the recess 2Aa differs from that of the first embodiment; the rest of the configuration is the same as in the first embodiment, so a duplicated description will be omitted. The recess 2Aa has a circumferential groove (also called a depression) 2Af that is flatly connected to the bottom wall 2Ad, which is formed by cutting the lower end of the side wall 2Ae radially outward. The circumferential groove 2Af is preferably located radially outward from the female thread 2Ac.

As in the first embodiment, the barrier member 87A is made up of a ring-shaped small diameter portion 87Aa, a hollow cone portion 87Ab that expands in diameter downward, and a ring-shaped large diameter portion 87Ac that is larger in diameter than the small diameter portion 87Aa, but the outer diameter of the large diameter portion 87Ac is larger than the inner diameter of the side wall 2e of the recess 2Aa. The rest of the configuration of the barrier member 87A is the same as in the first embodiment, so a repeated explanation will be omitted.

The outer diameter of the large diameter portion 87Ac is approximately equal to the inner diameter of the circumferential groove 2Af, and the thickness of the large diameter portion 87Ac is approximately equal to the axial width of the circumferential groove 2Af. When the barrier member 87A is assembled, the barrier member 87 is inserted into the recess 2Aa while the large diameter portion 87Ac is elastically deformed so as to reduce its diameter. When the large diameter portion 87Ac reaches the bottom wall 2Ad and is returned to its original state from the elastic deformation, the large diameter portion 87Ac expands in diameter and enters the circumferential groove 2Af and engages with the circumferential groove 2Af. This engagement fixes the barrier member 87A to the recess 2Aa in the axial direction and in the direction perpendicular to the axis. This modified example can be similarly applied to the embodiments described later.

(Second Modification)
5 is a perspective view of a barrier member 87B according to a second modified example. The barrier member 87B is composed only of a hollow cone portion 87Bb whose diameter increases toward the bottom. In other words, the barrier member 87B does not have a small diameter portion or a large diameter portion, and is therefore more easily elastically deformed than the first embodiment. However, it is also possible to provide either a small diameter portion or a large diameter portion. The rest of the configuration of the barrier member 87B is the same as that of the first embodiment, and therefore a duplicated description will be omitted. This modified example can be similarly applied to the embodiments described later.

Second Embodiment
Figures 6 and 7 are schematic cross-sectional views showing an expansion valve 1C in this embodiment. Figure 6 shows the expansion valve 1C in a non-communicating state. Figure 7 shows the expansion valve 1C in a communicating state. Figure 7 shows the maximum valve open state. In this embodiment, only the configuration of the barrier member 87C is different from that of the first embodiment, and the other configurations are the same as those of the first embodiment, so duplicated explanations will be omitted.

The barrier member 87C is made up of a ring-shaped large diameter portion 87Ca, a hollow cone portion 87Cb that tapers downward, and a ring-shaped small diameter portion 87Cc that is smaller in diameter than the large diameter portion 87Ca. The outer diameter of the large diameter portion 87Ca is approximately equal to the inner diameter of the second cylindrical portion 86d of the receiving member 86, and when the barrier member 87C is assembled, the outer periphery of the large diameter portion 87Ca abuts against the inner periphery of the second cylindrical portion 86d. In this embodiment, the receiving member 86 limits the movement of the barrier member 87C in the direction perpendicular to the axis.

The outer diameter of the small diameter portion 87Cc is larger than the inner diameter of the communication hole 2b and smaller than the inner diameter of the female thread 2c. The barrier member 87C is similar to the barrier member 87 of the first embodiment, but upside down. The rest of the configuration of the barrier member 87A is the same as in the first embodiment, so a duplicated description will be omitted.

In this embodiment, too, the barrier member 87C is compressed between the stopper member 84 and the bottom wall 2d of the recess 2a when the expansion valve 1 is in a non-communicating state. The barrier member 87C comes into contact with the lower end of the stopper member 84 and the bottom wall 2d of the recess 2a due to a restoring force generated by this compression.
Furthermore, the barrier member 87C is compressed and deformed in the process in which the expansion valve 1 changes from the non-communicating state as shown in FIG. 6 to the maximum open state as shown in FIG. 7. In this embodiment, for example, the small diameter portion 87Cc and the hollow cone portion 87Cb are deformed. Specifically, the small diameter portion 87Cc is deformed so as to be displaced radially inward. Note that the deformation of the barrier member 87C occurring between FIG. 6 and FIG. 7 is exaggerated for ease of understanding. The deformation of the barrier member 87C occurring between FIG. 6 and FIG. 7 is one example. The deformation of the barrier member 87C occurring between the non-communicating state and the maximum open state of the expansion valve 1 occurs according to the shape, dimensions, etc. of the barrier member 87. For example, the barrier member 87C may be formed such that the hollow cone portion 87Cb and the large diameter portion 87Ca are deformed, and the large diameter portion 87Ca is deformed so as to be displaced radially outward.

Third Embodiment
Fig. 8 is a schematic cross-sectional view showing an expansion valve 1D in this embodiment. Fig. 8 shows the expansion valve 1D in a communicating state. Fig. 8 shows the maximum valve open state. In this embodiment, only the configuration of the barrier member 87D is different from that of the first embodiment, and the other configurations are the same as those of the first embodiment, so duplicated explanations will be omitted.

The barrier member 87D is composed of an annular small diameter portion 87Da, a hollow cone portion 87Db that expands in diameter as it goes downward, and an annular large diameter portion 87Dc that is larger in diameter than the small diameter portion 87Da. The outer diameter of the large diameter portion 87Dc has a dimension that is larger than the inner diameter of the communication hole 2b and smaller than the inner diameter of the female thread 2c in both the communication state and the non-communication state. The inner diameter of the small diameter portion 87Da is slightly larger than the outer diameter of the working rod 5 that passes through it in the maximum open state, and a part of it can abut, and the refrigerant inside the barrier member 87D can reach the lower surface of the stopper member 84 through the gap between the small diameter portion 87Da and the working rod 5. The dimensions of the barrier member 87D are set so that the gap between the small diameter portion 87Da and the working rod 5 is secured regardless of whether the expansion valve 1 is in a non-communication state or a communication state. For example, even if the barrier member 87D is compressed and deformed when the expansion valve 1 is in communication, causing the small diameter portion 87Da to be displaced radially inward, the dimensions of the barrier member 87D are set so that a gap is secured between the small diameter portion 87Da and the actuation rod 5 through which the refrigerant can flow.

In this embodiment, the actuation rod 5 limits the movement of the barrier member 87D in a direction perpendicular to the axis. The rest of the configuration of the barrier member 87D is the same as in the first embodiment, so a duplicated description will be omitted.

Fourth Embodiment
Fig. 9 is a schematic cross-sectional view showing an expansion valve 1E in this embodiment. Fig. 9 shows the expansion valve 1E in a communicating state. Fig. 9 shows the maximum valve open state. In this embodiment, only the configuration of a barrier member 87E is different from that of the first embodiment, and the other configurations are the same as those of the first embodiment, so duplicated explanations will be omitted.

The barrier member 87E is formed by connecting an annular large diameter portion 87Ea, a hollow cone portion 87Eb that reduces in diameter as it approaches the bottom, and an annular small diameter portion 87Ec that is smaller in diameter than the large diameter portion 87Ea. In other words, the barrier member 87E is similar to the barrier member 87D of the third embodiment in an upside-down shape. The outer diameter of the small diameter portion 87Ec is larger than the inner diameter of the communication hole 2b in both the communication state and the non-communication state, and the outer diameter of the large diameter portion 87Ea is smaller than the inner diameter of the female thread 2c. The inner diameter of the small diameter portion 87Ec is slightly larger than the outer diameter of the working rod 5 that passes through it, so that a part of the small diameter portion 87E can abut against the working rod 5, and the refrigerant in the return flow path 23 can enter the inside of the barrier member 87E through the gap between the small diameter portion 87Ec and the working rod 5 and reach the underside of the stopper member 84.

The dimensions of the barrier member 87E are set so that a gap between the small diameter portion 87Ea and the actuating rod 5 is secured whether the expansion valve 1 is in a non-communicating state or a communicating state. For example, the dimensions of the barrier member 87E are set so that a gap through which the refrigerant can flow is secured between the small diameter portion 87Ea and the actuating rod 5 even when the barrier member 87E is compressed and deformed when the expansion valve 1 is in a communicating state, causing the small diameter portion 87Ea to deform so as to displace radially inward.

In this embodiment, the actuation rod 5 limits the movement of the barrier member 87E in a direction perpendicular to the axis. The rest of the configuration of the barrier member 87E is the same as in the first embodiment, so a duplicated description will be omitted.

Fifth Embodiment
Fig. 10 is a schematic cross-sectional view showing an expansion valve 1F in this embodiment. Fig. 10 shows the expansion valve 1F in a communication state. Fig. 10 shows the maximum valve open state. In this embodiment, only the configuration of the barrier member 87F is different from that of the first embodiment, and the other configurations are the same as those of the first embodiment, so duplicated explanations will be omitted.

The barrier member 87F is composed of an annular small diameter portion 87Fa, a hollow cone portion 87Fb that expands in diameter as it goes downward, and an annular large diameter portion 87Fc that is larger in diameter than the small diameter portion 87Fa. The dimensions of the barrier member 87F are set so that when the expansion valve 1 is in the maximum open state, the outer diameter of the large diameter portion 87Fc is approximately equal to the inner diameter of the side wall of the recess 2a, and the outer diameter of the small diameter portion 87Fa is larger than the outer diameter of the main body 84a of the stopper member 84 and smaller than the inner diameter of the second cylindrical portion 86d of the receiving member 86. The inner diameter of the small diameter portion 87Fa is slightly larger than the outer diameter of the operating rod 5 that passes through it, so that a part of the small diameter portion 87Fa can abut against the operating rod 5, and the refrigerant inside the barrier member 87F can reach the underside of the stopper member 84 through the gap between the small diameter portion 87Fa and the operating rod 5.

The dimensions of the barrier member 87F are set so that a gap between the small diameter portion 87Fa and the actuating rod 5 is secured whether the expansion valve 1 is in a non-communicating state or a communicating state. For example, the dimensions of the barrier member 87F are set so that a gap through which the refrigerant can flow is secured between the small diameter portion 87Fa and the actuating rod 5 even when the barrier member 87F is compressed and deformed when the expansion valve 1 is in a communicating state, causing the small diameter portion 87Fa to deform so as to displace radially inward.

In this embodiment, the side wall of the recess 2a limits the movement of the barrier member 87F in the direction perpendicular to the axis. The rest of the configuration of the barrier member 87F is the same as in the first embodiment, so a duplicated description will be omitted.

Sixth Embodiment
Fig. 11 is a schematic cross-sectional view showing an expansion valve 1G in this embodiment. Fig. 11 shows the expansion valve 1G in a communication state. Fig. 11 shows the maximum valve open state. In this embodiment, only the configuration of the barrier member 87G is different from that of the first embodiment, and the other configurations are the same as those of the first embodiment, so duplicated explanations will be omitted.

The barrier member 87G is made up of a ring-shaped large diameter portion 87Ga, a hollow cone portion 87Gb that tapers downward, and a ring-shaped small diameter portion 87Gc that is smaller in diameter than the large diameter portion 87Ga. The outer diameter of the large diameter portion 87Ga is approximately equal to the inner diameter of the second cylindrical portion 86d of the receiving member 86, and the outer periphery of the large diameter portion 87Ga abuts against the inner periphery of the second cylindrical portion 86d during assembly. In this embodiment, the receiving member 86 limits the movement of the barrier member 87G in the direction perpendicular to the axis.

The barrier member 87G is similar to the barrier member 87F of the fifth embodiment, but turned upside down. The outer diameter of the small diameter portion 87Gc is larger than the inner diameter of the communication hole 2b. The inner diameter of the small diameter portion 87Gc is slightly larger than the outer diameter of the actuation rod 5 that passes through it, allowing a part of the small diameter portion 87Gc to abut against the actuation rod 5, and the refrigerant in the return flow path 23 can enter the inside of the barrier member 87G through the gap between the small diameter portion 87Gc and the actuation rod 5 and reach the underside of the stopper member 84.

The dimensions of the barrier member 87G are set so that a gap between the small diameter portion 87Ga and the actuating rod 5 is secured whether the expansion valve 1 is in a non-communicating state or a communicating state. For example, the dimensions of the barrier member 87G are set so that a gap through which the refrigerant can flow is secured between the small diameter portion 87Ga and the actuating rod 5 even when the barrier member 87G is compressed and deformed when the expansion valve 1 is in a communicating state, causing the small diameter portion 87Ga to deform so as to be displaced radially inward.

Otherwise, the configuration of the barrier member 87G is the same as in the first embodiment, so a duplicated description will be omitted.

Seventh Embodiment
12 is a cross-sectional view of a barrier member 87H according to the seventh embodiment. In this embodiment, the barrier member 87H is made of an elastically deformable resin material, and is configured by connecting an upper end annular portion 87Ha, a bellows portion (also called a deformation portion) 87Hb having a bellows structure whose diameter changes periodically, and a lower end annular portion 87Hc having approximately the same diameter as the upper end annular portion 87Ha. The outer diameter of the upper end annular portion 87Ha is smaller than the outer diameter of the main body 84a of the stopper member 84, and the inner diameter of the lower end annular portion 87Hc is larger than the inner diameter of the communication hole 2b. The actuation rod 5 passes through the inside of the barrier member 87H.

Referring to FIG. 1, when the barrier member 87H is assembled to the expansion valve, the upper surface of the upper annular portion 87Ha abuts against the lower surface of the stopper member 84, and the lower surface of the lower annular portion 87Hc abuts against the upper surface of the bottom wall 2d, so that the entire circumferences of the respective portions are in close contact, and mainly the bellows portion 87Hb is elastically deformed. Due to the elastic deformation force generated at that time, the upper surface of the upper annular portion 87Ha is biased toward the lower surface of the stopper member 84, and the lower surface of the lower annular portion 87Hc is biased toward the upper surface of the bottom wall 2d. Therefore, even if foreign matter is mixed in the refrigerant, the foreign matter cannot pass from the inside to the outside of the barrier member 87H. This embodiment may be combined with the above-mentioned embodiment.

The present invention is not limited to the above-described embodiment. Any of the components of the above-described embodiment may be modified within the scope of the present invention. Any of the components of the above-described embodiment may be added or omitted.

This specification includes the disclosure of the following inventions.
(First aspect)
a valve body including a refrigerant flow path and a recess communicating with the refrigerant flow path via a communication hole;
a power element including a case, a diaphragm attached to the case, and a stopper member that abuts against the diaphragm inside the case, the power element being attached to the recess;
an actuating rod that is inserted into the communication hole and has one end in contact with the stopper member;
a barrier member disposed between the stopper member and an opposing wall facing the stopper member in the recess,
the barrier member is formed in a hollow cylindrical shape from an elastically deformable material and is disposed so as to surround the communication hole, and at least a portion of the barrier member is elastically deformed when assembled to the valve body, and the barrier member is brought into close contact with the stopper member and the opposing wall by an elastic force generated by the elastic deformation.
An expansion valve characterized by:

(Second Aspect)
The barrier member has a deformation portion that is elastically deformed when assembled to the valve body, and the deformation portion is a hollow cone portion whose diameter decreases toward one side in the axial direction of the expansion valve.
The expansion valve according to a first aspect,

(Third Aspect)
The hollow cone portion has a diameter on the stopper member side smaller than a diameter on the opposing wall side.
The expansion valve according to a second aspect,

(Fourth aspect)
The hollow cone portion has a diameter on the stopper member side larger than a diameter on the opposing wall side.
The expansion valve according to a second aspect,

(Fifth aspect)
The barrier member is restricted in movement in a direction perpendicular to the axis of the expansion valve by contacting a side wall of the recess or a case of the power element.
The expansion valve according to any one of the first to fourth aspects,

(Sixth Aspect)
a recess formed in the sidewall, a portion of the barrier member engaging the recess;
The expansion valve according to any one of the first to fifth aspects,

(Seventh aspect)
The barrier member abuts against the outer periphery of the working rod, thereby restricting movement in a direction perpendicular to the axis of the expansion valve.
The expansion valve according to any one of the first to fourth aspects,

(Eighth aspect)
The barrier member has a deformation portion that is elastically deformed when assembled to the valve body, and the deformation portion has a bellows structure.
The expansion valve according to any one of the first to seventh aspects,

Reference Signs List 1, 1C, 1D, 1E, 1F, 1G: Expansion valve 2, 2A: Valve body 3: Valve element 4: Biasing device 5: Actuating rod 6: Ring spring 8: Power element 87, 87A, 87B, 87C, 87D, 87E, 87F, 87G, 87H: Barrier member 20: Valve seat 21: First flow path 22: Second flow path 221: Intermediate chamber 23: Return flow path 27: Flow hole 28: Actuating rod insertion hole 29: Annular recess 41: Coil spring 42: Valve element support 43: Spring support member 81: Plug 82: Top cover member 83: Diaphragm 84: Stopper member 86: Support member 100: Refrigerant circulation system 101: Compressor 102: Condenser 104: Evaporator VC: Valve chamber

Claims (8)

a valve body including a refrigerant flow path and a recess communicating with the refrigerant flow path via a communication hole;
a power element including a case, a diaphragm attached to the case, and a stopper member that abuts against the diaphragm inside the case, the power element being attached to the recess;
an actuating rod having one end abutting against the stopper member and movable relative to the valve body;
a barrier member disposed between the stopper member and an opposing wall facing the stopper member in the recess,
the barrier member is formed in a hollow cylindrical shape from an elastically deformable material and is disposed so as to surround the communication hole, and at least a portion of the barrier member is elastically deformed when assembled to the valve body, and the barrier member is brought into close contact with the stopper member and the opposing wall by an elastic force generated by the elastic deformation.
An expansion valve characterized by: The barrier member has a deformation portion that is elastically deformed when assembled to the valve body, and the deformation portion is a hollow cone portion whose diameter decreases toward one side in the axial direction of the expansion valve.
2. The expansion valve according to claim 1 . The hollow cone portion has a diameter on the stopper member side smaller than a diameter on the opposing wall side.
3. The expansion valve according to claim 2. The hollow cone portion has a diameter on the stopper member side larger than a diameter on the opposing wall side.
3. The expansion valve according to claim 2. The barrier member is restricted in movement in a direction perpendicular to the axis of the expansion valve by contacting a side wall of the recess or a case of the power element.
The expansion valve according to any one of claims 1 to 4. a recess formed in the sidewall, a portion of the barrier member engaging the recess;
6. The expansion valve according to claim 5. The barrier member abuts against the outer periphery of the working rod, thereby restricting movement in a direction perpendicular to the axis of the expansion valve.
The expansion valve according to any one of claims 1 to 4. The barrier member has a deformation portion that is elastically deformed when assembled to the valve body, and the deformation portion has a bellows structure.
2. The expansion valve according to claim 1 .

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