JP7599211B2 - Power element and expansion valve equipped with same - Google Patents

Description

The present invention relates to a power element and an expansion valve equipped with the same.

Conventionally, refrigeration cycles used in air conditioners installed in automobiles use a temperature-sensing expansion valve that adjusts the amount of refrigerant passing through depending on the temperature.

In such an expansion valve, there is an inlet port through which high-pressure refrigerant is introduced and a valve chamber that communicates with the inlet port, and the top of the valve body is equipped with a valve member drive mechanism called a power element. The spherical valve body disposed in the valve chamber faces the valve seat that opens into the valve chamber, and is operated by an actuating rod driven by the power element to control the opening of the throttle passage between the valve seat.

The power element is composed of an upper cover member that forms a pressure actuated chamber, a thin diaphragm that elastically deforms when subjected to pressure, and a receiving member that is fixed to the valve body. The pressure actuated chamber formed by the upper cover member and the diaphragm is filled with a working gas. Furthermore, a stopper member is disposed in the lower space between the diaphragm and the receiving member.

In such a power element, heat is transferred between the refrigerant that flows from the valve body into the lower space of the power element and the working gas in the pressure actuated chamber. When the internal pressure of the pressure actuated chamber increases relatively, the diaphragm deforms so that the pressure actuated chamber expands, pushing the stopper member and pressing the working rod, separating the valve body from the valve seat. On the other hand, when the internal pressure of the pressure actuated chamber decreases relatively, the diaphragm returns to its original deformation, the pressing force of the working rod disappears, and the valve body seats on the valve seat.

Here, the internal pressure of the pressure actuated chamber changes depending on the gas or liquid phase of the working gas, such as an inert gas, sealed in the pressure actuated chamber. The pressure actuated chamber is a space sandwiched between the top cover member and the diaphragm, so that heat outside the expansion valve is transferred to the pressure actuated chamber via the top cover member, and heat in the pressure actuated chamber is transferred to the refrigerant via the diaphragm and stopper member. According to this heat balance, the gas in the pressure actuated chamber changes between gas and liquid phases, which causes the internal pressure of the pressure actuated chamber to change.

Therefore, when heat is transferred relatively quickly into the pressure chamber (the time constant is small), the working gas changes between gas and liquid phases too quickly, and the valve body repeatedly opens and closes, a phenomenon known as hunting, which is likely to occur, causing unstable control of the refrigeration cycle.

JP 2021-17961 A

In response to this, Patent Document 1 proposes a technique for increasing the time constant by forming part of the stopper member from a resin material. However, as mentioned above, the heat balance between the inside and outside of the pressure actuated chamber changes depending on various conditions such as the atmospheric temperature, so even if part of the stopper member is formed from a resin material, it is difficult to adequately prevent the hunting phenomenon under a wide range of conditions.

The present invention aims to provide a power element and an expansion valve equipped with the same that can effectively suppress the hunting phenomenon from a different perspective than conventional approaches.

In order to achieve the above object, the power element according to the present invention comprises:
a diaphragm, an upper cover member forming a pressure actuated chamber in which a working gas is sealed between the diaphragm and the upper cover member, a receiving member arranged on the opposite side of the diaphragm to the upper cover member, and a stopper member arranged in a lower space formed between the diaphragm and the receiving member ,
The upper cover member has a generally conical central portion and a peripheral portion extending from an outer edge of the central portion along the diaphragm,
the receiving member has a first annular flange portion, a cylindrical portion formed on an inner edge of the first annular flange portion, and a second annular flange portion extending inwardly from a lower end of the cylindrical portion that is opposite to the first annular flange portion,
the stopper member has a disk portion facing the diaphragm and an outer circumferential side of the disk portion being disposed between the diaphragm and the second annular flange portion, and a main body formed on the disk portion and disposed inside the second annular flange portion,
The stopper member is movable between a position where the disk portion abuts against the second annular flange portion and a position where the disk portion is separated from the second annular flange portion.
the disk portion abuts against the diaphragm in a state in which the disk portion abuts against the second annular flange portion,
The diaphragm is characterized in that, when the disk portion abuts the second annular flange portion, it has an uppermost point in a first range opposite the central portion of the diaphragm, and, when the disk portion abuts the second annular flange portion, it slopes downward from the uppermost point to a second range opposite the peripheral portion .

The present invention provides a power element and an expansion valve equipped with the same that can effectively suppress the hunting phenomenon from a different perspective than conventional approaches.

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 cross-sectional view showing the power element of the present embodiment. FIG. 3 is a cross-sectional view showing the power element of this embodiment in an exploded state. FIG. 4 is a cross-sectional view showing a power element of a comparative example. FIG. 5 is a cross-sectional view of a power element according to the second embodiment. FIG. 6 is a cross-sectional view showing the power element of this embodiment in an exploded state. FIG. 7 is a cross-sectional view of a power element according to the third embodiment. FIG. 8 is a cross-sectional view of a power element according to the fourth embodiment. FIG. 9 is a cross-sectional view of a power element according to the fifth embodiment. FIG. 10 is a cross-sectional view of a power element according to the sixth embodiment. FIG. 11 is a cross-sectional view showing the power element of this embodiment in an exploded state. FIG. 12 is a cross-sectional view of a power element according to the seventh embodiment. FIG. 13 is a cross-sectional view of a power element according to the eighth embodiment. FIG. 14 is a cross-sectional view of a power element according to the ninth embodiment. FIG. 15 is a cross-sectional view of a power element according to the tenth embodiment. FIG. 16 is a cross-sectional view of a power element according to the eleventh embodiment. FIG. 17 is a cross-sectional view of a power element according to the twelfth 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, regardless of the attitude of the expansion valve 1, the direction from the valve disc 3 to the actuating rod 5 is called the "upward direction."

First Embodiment
An overview of an expansion valve 1 according to the present embodiment will be described with reference to Fig. 1. Fig. 1 is a schematic cross-sectional view showing an example in which the expansion valve 1 according to the present embodiment is applied to a refrigerant circulation system 100. Fig. 2 is a cross-sectional view showing a power element according to the present embodiment. Fig. 3 is a cross-sectional view showing the power element according to the present embodiment in an exploded state.

In this embodiment, the expansion valve 1 is fluidly connected to the compressor 101, the condenser 102, and the evaporator 104. The axis of the expansion valve 1 is L.

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

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

The first flow path 21 and the valve chamber VS are connected by a connection path 21a having a smaller diameter than the first flow path 21. The valve chamber VS and the intermediate chamber 221 are connected via the valve seat 20 and the valve 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 disc 3 is disposed within the valve chamber VS. When the valve disc 3 is seated on the valve seat 20 of the valve body 2, the flow of refrigerant through the valve hole 27 is restricted. This state is called the non-communicating state. However, even when the valve disc 3 is seated on the valve seat 20, a restricted amount of refrigerant may flow. On the other hand, when the valve disc 3 is separated from the valve seat 20, the flow of refrigerant passing through the valve hole 27 increases. This state is called the communicating state.

The actuating rod 5 is inserted through the valve 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.

The biasing device 4 has a coil spring 41 made of a wire 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 VS and adjusting the biasing force of the coil spring 41.

(Power element configuration)
Next, a description will be given of the power element 8. As shown in FIG. 2, 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 top cover member 82 is formed by pressing a metal plate, and is made up of a central portion 82b that protrudes into a generally conical shape and a peripheral portion 82c that extends along the diaphragm 83. An opening 82a is formed at the top of the central portion 82b, and can be sealed with a plug 81.

The diaphragm 83 is made of a thin metal (e.g., SUS) plate material with multiple concentric circular projections and recesses, and has an outer diameter that is approximately the same as the outer diameters of the top cover member 82 and the receiving member 86. In this embodiment, the diaphragm 83 has a generally flat shape that is perpendicular to the axis.

The receiving member 86 is formed by press-molding a metal plate. Specifically, the receiving member 86 has a first annular flange portion 86a having an outer diameter approximately the same as the outer diameter of the upper cover member 82, a first cylindrical portion 86b connected to the inner circumference of the first annular flange portion 86a, a second annular flange portion 86c connected to the lower end of the first cylindrical portion 86b and facing radially inward, and a second cylindrical portion 86d connected to the inner circumference of the second annular flange portion 86c. A male thread portion 86e is formed on the outer circumference of the lower end side of the second cylindrical portion 86d.

The stopper member 84 has a disk portion 84a that faces the diaphragm 83, a cylindrical main body 84b that is connected to the lower side of the disk portion 84a, and a blind hole-like fitting hole 84c that is formed in the center of the lower surface of the main body 84b. The upper surface 84d of the stopper member 84 has a conical shape that decreases in diameter toward the center. In other words, the stopper member 84 has a convex shape that faces upward.

As shown in the cross section of Figure 3, the inclination angle θ of the upper surface 84d (the inclination angle with respect to a plane perpendicular to the axis, where the downward angle from the plane perpendicular to the axis is considered positive) is 5 degrees or more. Any inclination angle greater than 0 degrees is sufficient. It is preferable that the inclination angle is, for example, 30 degrees or less, since this reduces the height of the power element 8. In this embodiment, as shown in Figure 2, the lower surface of the diaphragm 83 is in close contact with at least the center side of the upper surface 84d (inside point P, described later). In addition, the outer periphery of the lower surface of the disk portion 84a is supported by the upper surface of the second annular flange portion 86c.

The assembly procedure for the power element 8 will be described with reference to Figure 3. While placing the stopper member 84 between the diaphragm 83 and the receiving member 86, the outer peripheries of the upper cover member 82, the diaphragm 83, and the receiving member 86 are overlapped, and the outer peripheries are integrated by peripheral welding, for example, by TIG welding, laser welding, plasma welding, etc.

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 82a formed in the top cover member 82, and the opening 82a is then sealed with a plug 81, which is then fixed to the top cover member 82 by projection welding or the like.

At this time, the diaphragm 83 is pressurized by the working gas sealed in the pressure actuated chamber PO in such a way that it juts out towards the receiving member 86, and is supported by contacting the upper surface 84d of the stopper member 84 disposed in the lower space LS surrounded by the diaphragm 83 and the receiving member 86. In addition, since the upper surface 84d of the stopper member 84 has a conical shape, the diaphragm 83 also deforms following that shape, and is inclined at an angle θ from the center to the periphery as shown in FIG. 2. In other words, the diaphragm 83 has an inclined surface that is monotonically inclined all around from the center to the periphery, or the diaphragm 83 is inclined downward from the top point of the diaphragm 83 to the periphery, and is inclined at an inclination angle exceeding 0 degrees over at least one path.

The "top point" refers to the point closest to the top cover member 82 in the direction of the axis L, and in this embodiment, it is the center of the diaphragm 83. The "top point" also includes a range around it that can be considered to have the same height as the top point.
In addition, in this specification, the term "path" refers to a continuous portion through which the liquefied working gas on the diaphragm flows due to gravity. Furthermore, the term "periphery" refers to a region that is at least half the maximum diameter of the stopper member, and preferably refers to the outermost edge (point P in FIG. 2) of the area where the diaphragm 83 abuts against the stopper member 84 or a region radially outward of the edge.

It is preferable that the diaphragm 83 has an upwardly convex shape on the inside from the outermost edge (point P) of the area where the diaphragm 83 and the stopper member 84 abut. Furthermore, in the assembled state, it is preferable that the line connecting the center of the underside of the diaphragm 83 (or a point on the underside of the diaphragm 83 directly below the uppermost point) and the outermost edge (point P) of the area where the diaphragm 83 and the stopper member 84 abut is inclined by 5 degrees or more with respect to a plane perpendicular to the axis of the power element 8.

When the power element 8 assembled as described above is attached to the valve body 2, the male threaded portion 86e provided on the outer periphery of the lower end of the second cylindrical portion 86d of the receiving member 86 is screwed into the female threaded portion 2b formed on the inner periphery of the recessed portion 2a that communicates with the return flow path 23 of the valve body 2. When the male threaded portion 86e is screwed into the female threaded portion 2b, the lower end 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 seal SL interposed between the power element 8 and the valve body 2 prevents refrigerant from leaking from the recess 2a when the power element 8 is attached to the valve body 2. In this state, the lower space LS of the power element 8 communicates with the return flow path 23, i.e., the internal pressure is the same.

(Expansion valve operation)
An example of the operation of the expansion valve 1 will be described with reference to Fig. 1. 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 VS via the first flow path 21.

When the valve body 3 is seated on the valve seat 20 (in a non-communicating state), the flow rate of the refrigerant sent from the valve chamber VS through the valve 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), the flow rate of the refrigerant sent from the valve chamber VS through the valve 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.

In FIG. 1, the power element 8 is provided with a pressure actuated chamber PO and a lower space LS separated by a diaphragm 83. Therefore, when the working gas in the pressure actuated chamber PO is liquefied, the diaphragm 83 and the stopper member 84 rise, and the working rod 5 moves upward in response to the biasing force of the coil spring 41. On the other hand, when the liquefied working gas is vaporized, the diaphragm 83 and the stopper member 84 are pressed downward, and the working rod 5 moves downward. In this way, the expansion valve 1 is switched between the open and closed states.

Furthermore, the lower space LS of the power element 8 is connected to the return flow path 23. 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 FIG. 1, 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.

(Power element for comparison)
4 is a cross-sectional view showing a power element 8' of a comparative example. The power element 8' has a different shape of a stopper member 84' from the above embodiment. Specifically, an upper surface 84d' of the stopper member 84' is a flat surface perpendicular to the axis. The rest of the configuration is the same as in the above embodiment, so the same reference numerals are used and repeated explanations are omitted.

During operation of the expansion valve, the outer surface of the power element 8' (particularly the top cover member 82) is exposed to the atmosphere. Therefore, heat is transferred from the atmosphere to the pressure actuated chamber PO via the top cover member 82. Meanwhile, since the pressure actuated chamber PO is in contact with the stopper member 84' and the diaphragm 83, heat is transferred from the pressure actuated chamber PO to the refrigerant via these.

The distance between the central portion 82b of the upper cover member 82 and the diaphragm 83 at the center of the pressure actuated chamber PO is smaller than the distance between the peripheral portion 82c and the diaphragm 83 at the peripheral side of the pressure actuated chamber PO. Therefore, the working gas at the center of the diaphragm 83 is more likely to liquefy and turn into liquid LQ because the heat that escapes to the refrigerant is greater than the heat that is transferred from the central portion 82b.

However, in the power element 8' of the comparative example, the upper surface 84d' of the stopper member 84' is maintained approximately horizontal, and the surface of the diaphragm 83 is provided with concentric irregularities, so that the liquid LQ formed by the liquefied working gas remains near the center of the upper surface of the diaphragm 83 (a relatively low temperature area) as shown by the dotted line in Figure 4, and remains in a liquefied state. In this way, if the liquefied state of the working gas is fixed locally within the pressure actuated chamber PO, there is a risk that the time constant will become small, which will lead to the hunting phenomenon of the valve body 3.

In contrast, according to this embodiment, the upper surface 84d of the stopper member 84 has a conical shape with an inclination angle of 5 degrees or more, so that, as shown in FIG. 2, when at least the disk portion 84a is in contact with the receiving member 86, the diaphragm 83 also deforms into a conical shape following that shape. Therefore, the working gas liquefied below the center portion 82b of the upper cover member 82 flows along the diaphragm 83 to the periphery (radially outward) due to gravity, as shown by the solid arrow.

The working gas that flows to the periphery reaches the lower part of the periphery 82c of the upper cover member 82, but because the distance between the periphery 82c and the diaphragm 83 is small, it is easily exposed to heat from the atmosphere from the periphery 82c, which promotes vaporization. The vaporized working gas leaves the diaphragm 83 and moves downward to the center part 82b as shown by the dotted arrow, where it is liquefied again. Since the heat transfer between the pressure actuated chamber PO and the refrigerant does not change, there is almost no influence from the ambient temperature, but the time constant is increased by the time difference for the working gas to vaporize around the diaphragm 83. In this way, by repeatedly circulating the working gas between the liquid phase and the gas phase in the pressure actuated chamber PO, an appropriate time constant can be obtained even under a wide range of conditions where the atmospheric temperature and the refrigerant temperature change, and the hunting phenomenon of the valve body 3 can be effectively suppressed.

Second Embodiment
Fig. 5 is a cross-sectional view of a power element 8A according to a second embodiment. Fig. 6 is a cross-sectional view showing the power element 8A of this embodiment in an exploded state. In this embodiment, only the shape of the stopper member 84A is different from that of the above-mentioned embodiment. Since the other configurations are the same as those of the above-mentioned embodiment, the same reference numerals are used and duplicated explanations are omitted.

The stopper member 84A has a circular upper surface 84Ad perpendicular to the axis and a conical surface 84Ae whose diameter increases as it moves away from the upper surface 84Ad in the axial direction. As shown in FIG. 6, the diaphragm 83 has a generally flat shape perpendicular to the axis, as in the above-described embodiment, but when the diaphragm 83 comes into contact with the stopper member 84A in the assembled power element 8A, it deforms so that the center rises.

More specifically, as shown in FIG. 5, with at least the disk portion 84Aa in contact with the receiving member 86, the lower surface of the diaphragm 83 abuts against the conical surface 84Ae of the stopper member 84A and is pressed upward. As a result, even though the upper surface 84Ad and the diaphragm 83 do not come into contact, the diaphragm 83 deforms so that the center rises, allowing the working gas liquefied near the center of the diaphragm 83 to flow to the periphery. In addition, a space is created between the center of the diaphragm 83 and the upper surface 84Ad of the stopper member 84A, which allows the time constant to be adjusted.

Third Embodiment
7 is a cross-sectional view of a power element 8B according to a third embodiment. In this embodiment, only the shape of a stopper member 84B is different from that of the above-described embodiment. Since the other configurations are the same as those of the above-described embodiment, the same reference numerals are used and a duplicated description will be omitted.

The stopper member 84B has a spherical upper surface 84Bd. In this embodiment, the diaphragm 83 also has a generally flat shape perpendicular to the axis, but when the diaphragm 83 comes into contact with the stopper member 84B in the assembled power element 8B, it deforms so that the center rises.

More specifically, as shown in FIG. 7, with at least the disk portion 84Ba in contact with the receiving member 86, the lower surface of the diaphragm 83 comes into contact with the upper surface 84Bd of the stopper member 84B and is pressed upward. As a result, the center of the diaphragm 83 deforms so that it rises into a spherical (convex) shape, allowing the working gas liquefied near the center of the diaphragm 83 to flow toward the periphery. According to this embodiment, because the upper surface 84Bd of the stopper member 84B that comes into contact with the diaphragm 83 is spherical, the stress generated in the diaphragm 83 during contact can be alleviated.

Fourth Embodiment
8 is a cross-sectional view of a power element 8C according to a fourth embodiment. In this embodiment, only the shape of a stopper member 84C is different from that of the above-described embodiment. Since the other configurations are the same as those of the above-described embodiment, the same reference numerals are used and the repeated description will be omitted.

The stopper member 84C has a conical central upper surface 84Cd that expands in diameter as it moves away from the diaphragm 83 in the axial direction, and a spherical surface 84Ce that expands in diameter as it moves away from the central upper surface 84Cd in the axial direction. In this embodiment, the diaphragm 83 also has a generally flat shape perpendicular to the axis, but when it comes into contact with the stopper member 84C in the assembled power element 8C, it deforms so that the center rises.

More specifically, as shown in FIG. 8, with at least the disk portion 84Aa in contact with the receiving member 86, the lower surface of the diaphragm 83 comes into contact with the central upper surface 84Cd and the spherical surface 84Ce of the stopper member 84A and is pressed upward. As a result, the diaphragm 83 deforms so that the center rises in accordance with the central upper surface 84Cd and the spherical surface 84Ce, allowing the working gas liquefied near the center of the diaphragm 83 to flow toward the periphery.

Fifth Embodiment
9 is a cross-sectional view of a power element 8D according to a fifth embodiment. In this embodiment, only the shape of a stopper member 84D is different from that of the above-described embodiment. Since the other configurations are the same as those of the above-described embodiment, the same reference numerals are used and the repeated description will be omitted.

The stopper member 84D has an uppermost point 84Df on the upper surface 84Dd at a position that does not overlap with the axis, and the upper surface 84Dd is inclined from the uppermost point 84Df toward the periphery. Therefore, the inclination angle of the upper surface 84Dd varies depending on the position, but it is preferable that the shallowest inclination angle is 5 degrees or more. Note that the uppermost point 84Df is located at a position other than the periphery of the stopper member 84D, and is preferably located radially inward from 1/2 of the maximum diameter, for example.
In this embodiment as well, the diaphragm 83 has a generally flat shape perpendicular to the axis, but when it comes into contact with the stopper member 84D in the assembled power element 8D, it deforms so as to rise most at the uppermost point 84Df.

More specifically, as shown in FIG. 9, with at least the disk portion 84Da in contact with the receiving member 86, the lower surface of the diaphragm 83 comes into contact with the upper surface 84Dd of the stopper member 84D and is pressed upward. As a result, the diaphragm 83 deforms so as to rise most at the uppermost point 84Df. In other words, the diaphragm 83 has an inclined surface that slopes monotonically from the point on the diaphragm 83 that is farthest from the stopper member 84D toward the periphery. This allows the working gas that has been liquefied near the uppermost point 84Df of the diaphragm 83 to flow toward the periphery.

Sixth Embodiment
Fig. 10 is a cross-sectional view of a power element 8F according to the sixth embodiment. Fig. 11 is a cross-sectional view showing the power element 8F of this embodiment in an exploded state. In this embodiment, only the shapes of a diaphragm 83F and a stopper member 84F are different from those of the above-mentioned embodiment. Since the other configurations are the same as those of the above-mentioned embodiment, the same reference numerals are used and duplicated explanations are omitted.

As shown in FIG. 11, the stopper member 84F has a flat upper surface 84Fd that is perpendicular to the axis, while the diaphragm 83F has a plate center portion 83Fa that is formed in a cone shape in a free state where it is not subjected to external force. Therefore, the diaphragm 83F has an upwardly convex shape in a free state, and the inclination angle θ of the plate center portion 83Fa is 5 degrees or more.

As shown in FIG. 10, with at least the disk portion 84Fa in contact with the receiving member 86, the outer periphery of the plate center portion 83Fa of the diaphragm 83F is supported by the upper surface 84Fd of the stopper member 84F. In this state, the plate center portion 83Fa of the diaphragm 83F rises in a conical shape, which allows the working gas liquefied near the plate center portion 83Fa to flow to the periphery. In addition, a space is created between the plate center portion 83Fa and the upper surface 84Ad of the stopper member 84A, which allows the time constant to be adjusted.

Seventh Embodiment
12 is a cross-sectional view of a power element 8G according to the seventh embodiment. In this embodiment, only the shape of a diaphragm 83G is different from that of the sixth embodiment. The other configurations, including the stopper member 84F, are the same as those in the above-mentioned embodiments, so the same reference numerals are used and the repeated description will be omitted.

The diaphragm 83G has a plate center portion 83Ga that is spherical around the axis when in a free state without being subjected to external forces.

As shown in FIG. 12, with at least the disk portion 84Fa in contact with the receiving member 86, the outer periphery of the plate center portion 83Ga of the diaphragm 83G is supported by the upper surface 84Fd of the stopper member 84F. Therefore, even though the upper surface 84Fd and the center of the plate center portion 83Ga do not come into contact, the center of the diaphragm 83G deforms so that it rises into a spherical shape, which allows the working gas liquefied near the center of the diaphragm 83G to flow toward the periphery.

Eighth embodiment
13 is a cross-sectional view of a power element 8H according to the eighth embodiment. In this embodiment, only the shape of a diaphragm 83H is different from that of the sixth embodiment. The other configurations, including the stopper member 84F, are the same as those in the above-mentioned embodiments, so the same reference numerals are used and the repeated description will be omitted.

In a free state where it is not subjected to external forces, the diaphragm 83H has a plate center portion 83Ha that is spherical about the axis, and a plate cone portion 83Hb that expands in diameter as it moves away from the plate center portion 83Ha along the axis.

As shown in FIG. 13, with at least the disk portion 84Fa in contact with the receiving member 86, the outer periphery of the plate cone portion 83Hb of the diaphragm 83H is supported by the upper surface 84Fd of the stopper member 84F. Therefore, even though the upper surface 84Fd does not contact the plate central portion 83Ha or the plate cone portion 83Hb, the diaphragm 83H deforms so that the center rises into a spherical and conical shape, which allows the working gas liquefied near the center of the diaphragm 83H to flow to the periphery.

Ninth embodiment
14 is a cross-sectional view of a power element 8I according to the ninth embodiment. In this embodiment, only the shape of the diaphragm 83I is different from that of the sixth embodiment. The other configurations, including the stopper member 84F, are the same as those in the above-mentioned embodiments, so the same reference numerals are used and the repeated description will be omitted.

In a free state where no external force is applied, the diaphragm 83I has an uppermost point 83Ic at a position that does not overlap with the axis, and the central portion 83Ia of the diaphragm 83I is inclined from the uppermost point 83Ic toward the periphery. For this reason, the inclination angle of the central portion 83Ia varies depending on the position, and it is preferable that the shallowest inclination angle is 5 degrees or more, but it is sufficient that the maximum inclination angle is 5 degrees or more.

As shown in FIG. 14, the diaphragm 83I is supported by the stopper member 84 with at least the disk portion 84Fa in contact with the receiving member 86, and the central portion 83Ia of the diaphragm 83I is inclined from the highest point 83Ic toward the periphery. Therefore, even though the upper surface 84Fd and the center of the diaphragm 83I do not contact each other, the diaphragm 83I deforms so that the highest point 83Ic rises to the highest point, thereby allowing the working gas liquefied near the center of the diaphragm 83I to flow toward the periphery. According to this embodiment, even if it is difficult to ensure the height of the highest point 83Ic, a maximum inclination angle of 5 degrees or more can be obtained.

Tenth embodiment
15 is a cross-sectional view of a power element 8J according to a tenth embodiment. In this embodiment, only the shape of a stopper member 84J is different from that of the first embodiment. The other configurations are the same as those of the above-mentioned embodiments, so the same reference numerals are used and repeated explanations are omitted.

The stopper member 84J has a metal body 84J1 and a resin heat insulator 84J2. The metal body 84J1 has a disk portion 84Ja facing the diaphragm 83, a cylindrical main body 84Jb connected below the disk portion 84Ja, a blind hole-shaped fitting hole 84Jc formed in the center of the bottom surface of the main body 84Jb, and a circular recess 84Jd formed in the center of the top surface of the disk portion 84Ja. The surrounding upper surface 84Je around the circular recess 84Jd is a conical surface whose diameter decreases as it moves upward along the axis.

The insulator 84J2 is cylindrical with an outer diameter equal to the inner diameter of the circular recess 84Jd, and its part top surface 84Jf is a conical surface that decreases in diameter as it moves upward along the axis. When the insulator 84J2 is fitted into the circular recess 84Jd and fixed by adhesive or the like, it is preferable that the peripheral top surface 84Je and the part top surface 84Jf are connected without any steps. In addition, it is preferable that the inclination angle between the peripheral top surface 84Je and the part top surface 84Jf is 5 degrees or more.

In this embodiment, the diaphragm 83 also has a generally flat shape perpendicular to the axis, but when it comes into contact with the metal body 84J1 and the heat insulator 84J2 of the stopper member 84J in the assembled power element 8J, it deforms to its highest point, forming a conical shape. This allows the working gas liquefied near the center of the diaphragm 83 to flow to the periphery.

In this embodiment, the heat insulator 84J2 is disposed between the diaphragm 83 and a part of the metal body 84J1, so the working gas is more easily vaporized than when the stopper member is made of metal only, and a large time constant can be ensured.

Eleventh Embodiment
16 is a cross-sectional view of a power element 8K according to an eleventh embodiment. In this embodiment, only the shape of a stopper member 84K is different from that of the first embodiment. Since the other configurations are the same as those of the above-mentioned embodiments, the same reference numerals are used and a duplicated description will be omitted.

The stopper member 84K has a metal body 84K1 and a resin insulator 84K2. The metal body 84K1 has a disk portion 84Ka facing the diaphragm 83, a cylindrical main body 84Kb connected to the lower side of the disk portion 84Ka, a blind hole-like fitting hole 84Kc formed in the center of the lower surface of the main body 84Kb, and an annular recess 84Kd formed near the outer periphery of the disk portion 84Ka. The central upper surface 84Ke formed on the radial inside of the annular recess 84Kd is a conical surface whose diameter decreases as it moves upward along the axis.

The insulator 84K2 is ring-shaped with inner and outer diameters equal to the outer and inner diameters of the annular recess 84Kd, and its part top surface 84Kf is a conical surface that tapers upward along the axis. When the insulator 84K2 is fitted into the circular recess 84Jd and fixed by adhesive or the like, it is preferable that the central top surface 84Ke and the part top surface 84Kf are connected without any steps. In addition, it is preferable that the inclination angle between the peripheral top surface 84Je and the part top surface 84Kf is 5 degrees or more.

In this embodiment, the diaphragm 83 also has a generally flat shape perpendicular to the axis, but when it comes into contact with the metal body 84K1 and the heat insulator 84K2 of the stopper member 84K in the assembled power element 8K, it deforms to its highest point, forming a conical shape. This allows the working gas liquefied near the center of the diaphragm 83 to flow to the periphery.

In this embodiment, the heat insulator 84K2 is disposed between the diaphragm 83 and a part of the metal body 84K1, so the working gas is more easily vaporized than when the stopper member is made of metal only, and a large time constant can be ensured.

Twelfth Embodiment
17 is a cross-sectional view of a power element 8L according to a twelfth embodiment. In this embodiment, only the shape of a stopper member 84L is different from that of the first embodiment. Since the other configurations are the same as those of the above-mentioned embodiments, the same reference numerals are used and a duplicated description will be omitted.

The stopper member 84L has a disk portion 84La facing the diaphragm 83, a cylindrical main body 84Lb connected to the lower side of the disk portion 84La, a blind hole-shaped fitting hole 84Lc formed in the center of the lower surface of the main body 84Lb, and a raised portion 84Ld formed in the center of the disk portion 84La. The central upper surface 84Le of the raised portion 84Ld is a conical surface whose diameter decreases as it moves upward along the axis, and the inclination angle is preferably 5 degrees or more.

In this embodiment, the diaphragm 83 also has a generally flat shape perpendicular to the axis, but when it comes into contact with the raised portion 84Ld of the stopper member 84L in the assembled power element 8L, it deforms to its highest point, forming a conical shape. This allows the working gas liquefied near the center of the diaphragm 83 to flow to the periphery.

In this embodiment, the diaphragm 83 only contacts the raised portion 84Ld, and does not contact the disk portion 84La other than the raised portion 84Ld. Therefore, the working gas is more easily vaporized than when the diaphragm 83 is in contact with the stopper member over a wide area, and a large time constant can be ensured.

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.

1: Expansion valve 2: Valve body 3: Valve element 4: Biasing device 5: Actuating rod 6: Ring spring 8-8L: Power element 20: Valve seat 21: First flow path 22: Second flow path 23: Return flow path 27: Valve hole 41: Coil spring 42: Valve element support 43: Spring receiving member 100: Refrigerant circulation system 101: Compressor 102: Condenser 104: Evaporator VS: Valve chamber

Claims (12)

a diaphragm, an upper cover member forming a pressure actuated chamber in which a working gas is sealed between the diaphragm and the upper cover member, a receiving member arranged on the opposite side of the diaphragm to the upper cover member, and a stopper member arranged in a lower space formed between the diaphragm and the receiving member ,
The upper cover member has a generally conical central portion and a peripheral portion extending from an outer edge of the central portion along the diaphragm,
the receiving member has a first annular flange portion, a cylindrical portion formed on an inner edge of the first annular flange portion, and a second annular flange portion extending inwardly from a lower end of the cylindrical portion that is opposite to the first annular flange portion,
the stopper member has a disk portion facing the diaphragm and an outer circumferential side thereof disposed between the diaphragm and the second annular flange portion, and a main body formed on the disk portion and disposed inside the second annular flange portion,
The stopper member is movable between a position where the disk portion abuts against the second annular flange portion and a position where the disk portion is separated from the second annular flange portion.
the disk portion abuts against the diaphragm in a state in which the disk portion abuts against the second annular flange portion,
the diaphragm has an uppermost point in a first range facing the central portion of the diaphragm when the disk portion is in contact with the second annular flange portion, and is inclined downward from the uppermost point to a second range facing the peripheral portion when the disk portion is in contact with the second annular flange portion .
A power element characterized by: The diaphragm has an upwardly convex shape on the inner side from the outermost peripheral edge of the range where the diaphragm and the stopper member are in contact with each other.
A power element according to claim 1 . The surface of the stopper member that comes into contact with the diaphragm has an upwardly convex shape.
A power element according to claim 2. The diaphragm and the stopper member are in close contact with each other from the outermost periphery of the area where the diaphragm and the stopper member are in contact with each other,
A power element according to claim 3. The diaphragm has an upwardly convex shape in a free state.
A power element according to claim 2 or 3. A space is formed between the center of the diaphragm and the stopper member.
A power element according to claim 4 or 5. the diaphragm is inclined at an inclination angle greater than 0 degrees over at least one path from the top of the diaphragm to the periphery;
A power element according to any one of claims 1 to 6. In a cross section passing through the axis of the power element, a line connecting a point corresponding to the uppermost point on a surface of the diaphragm facing the stopper member and an outermost peripheral edge of an area where the diaphragm and the stopper member are in contact is inclined by 5 degrees or more with respect to a plane perpendicular to the axis of the power element.
A power element according to any one of claims 1 to 7. The uppermost point of the diaphragm or the uppermost point of the stopper member is offset from the axis of the power element.
A power element according to any one of claims 1 to 8. A heat insulating material is disposed on a surface of the stopper member facing the diaphragm.
A power element according to any one of claims 1 to 9. A power element according to any one of claims 1 to 9, characterized in that only the center of the diaphragm abuts against the stopper member. An expansion valve having a power element according to any one of claims 1 to 11.

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