JP7390699B2 - expansion valve - Google Patents

Description

The present invention relates to an expansion valve.

2. Description of the Related Art Conventionally, in a refrigeration cycle used in an air conditioner installed in an automobile, a temperature-sensitive expansion valve is used to adjust the amount of refrigerant passing through depending on the temperature. One type of expansion valve includes an actuation rod disposed in the refrigerant path of low-pressure refrigerant from the evaporator to the compressor, and a power element that drives a valve body via the actuation rod. The sensitive chamber of the power element is filled with a working gas filled with a refrigerant gas that is the same as or different from the refrigerant flowing through the refrigeration cycle and an inert gas at an appropriate mixing ratio.

When heat transfer occurs between the low-pressure refrigerant passing through the refrigerant passage and the working gas in the sensitive chamber of the power element, the internal pressure of the working gas in the sensitive chamber changes due to the temperature change. Utilizing this internal pressure change, the valve body can be driven via the actuating rod to open or close the valve. The opening characteristics of an expansion valve depend on the temperature-pressure characteristics of the working gas, and the slope of the characteristic curve indicates the magnitude of the pressure fluctuation that occurs when the temperature changes, so it is an important factor that determines the valve opening characteristics. .

In Patent Document 1, a graph showing the opening characteristics of an expansion valve is shown as an example. As shown in Patent Document 1, the valve opening characteristics of an expansion valve are controlled by utilizing the fact that the valve opening pressure changes with respect to the temperature of the temperature sensing part by using a working gas made by adding an appropriate amount of inert gas to a single refrigerant. Can be changed.

JP2013-250020A

By the way, fixed capacity compressors and variable capacity compressors are known as compressors used in refrigeration cycles. A fixed capacity compressor has a fixed capacity for compressing refrigerant, and prevents overcooling by stopping the operation of the compressor when the target temperature is reached. On the other hand, variable capacity compressors prevent overcooling and save energy by varying the capacity of the compressor that compresses refrigerant, and have the characteristic that they do not stop operating even under low loads.

In a typical refrigeration cycle, a small amount of oil is mixed with the refrigerant and circulated through the cycle in order to reduce wear on the sliding parts, but variable displacement compressors are designed to continue operating even at low loads. , it is necessary to circulate the refrigerant for lubrication. Therefore, in a refrigeration cycle equipped with a variable capacity compressor, an expansion valve is often used that has a valve opening characteristic (cross charge) that allows the valve to open slightly even when the temperature of the temperature sensing part is low.

In such a cross-charge valve-opening characteristic, the composition of the working gas is changed to make the slope of the curve representing the valve-opening characteristic gentle so that the temperature-sensing part can easily open the valve even at a low temperature. However, according to such valve opening characteristics, when the temperature sensing portion becomes high temperature, the degree of superheat (compressor suction gas temperature - evaporation temperature) increases. If the degree of superheating increases during high loads, it becomes difficult for the valve to open in response to refrigerant pressure, which may cause the evaporator outlet temperature to become too high, leading to a decrease in efficiency. However, desired valve opening characteristics cannot be obtained simply by changing the composition of the working gas.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an expansion valve that can suppress the degree of superheating at high loads even when used in a refrigeration cycle using a variable capacity compressor, for example.

In order to achieve the above object, the power element according to the present invention includes:
a valve body disposed within a flow path through which fluid passes and having a valve seat;
a valve body that restricts or allows passage of the fluid through the valve seat by moving toward or away from the valve seat;
a coil spring that urges the valve body toward the valve seat;
an actuating rod having one end in contact with the valve body;
a power element that drives the actuating rod;
The power element includes an upper lid member, a diaphragm, a receiving member disposed on a side opposite to the upper lid member across the diaphragm, and a stopper member disposed between the diaphragm and the actuation rod. Prepare,
When the diaphragm presses the stopper member toward the valve body, driving force is transmitted from the stopper member to the valve body via the actuation rod,
A temperature-sensitive material having a larger coefficient of thermal expansion above the predetermined temperature than below the predetermined temperature is disposed in a component disposed in the driving force transmission path between the diaphragm and the valve body. It is characterized by

According to the present invention, it is possible to provide an expansion valve that can suppress the degree of superheating at high loads even when used in a refrigeration cycle using a variable capacity compressor, for example.

FIG. 1 is a schematic sectional view schematically showing an example in which the expansion valve according to the present embodiment is applied to a refrigerant circulation system. FIG. 2 is a sectional view of the power element 8. FIG. 3 is a graph showing the opening pressure characteristics of the expansion valve 1. FIG. 4 is an enlarged cross-sectional view showing a power element 8A according to a first modification example attached to the valve body 2. As shown in FIG. FIG. 5 is an enlarged sectional view showing a power element 8B according to a second modification example attached to the valve body 2. As shown in FIG.

Embodiments according to the present invention will be described below with reference to the drawings.

(Definition of direction)
In this specification, the direction from the valve body 3 toward the actuation rod 5 is defined as an "upward direction," and the direction from the actuation rod 5 toward the valve body 3 is defined as a "downward direction." Therefore, in this specification, the direction from the valve body 3 toward the actuating rod 5 is referred to as the "upward direction" regardless of the attitude of the expansion valve 1.

Referring to FIG. 1, an overview of an expansion valve 1 including a power element in this embodiment will be described. FIG. 1 is a schematic sectional view schematically showing an example in which the expansion valve 1 according to the present embodiment is applied to a refrigerant circulation system 100. In this example, expansion valve 1 is fluidly connected to compressor 101 , condenser 102 and evaporator 104 . Let L be the axis of the expansion valve 1.

In FIG. 1, an expansion valve 1 includes a valve body 2 including a valve chamber VS, a valve body 3, a biasing device 4, an actuation 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 referred to as 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 referred to as an outlet side flow path), and the fluid in the valve chamber VS is discharged to the outside of the expansion valve via the valve passage hole 27, the intermediate chamber 221, and the discharge side flow path. be done.

The first flow path 21 and the valve chamber VS communicate with each other through a connecting path 21a having a smaller diameter than the first flow path 21. The valve chamber VS and the intermediate chamber 221 communicate with each other via the valve seat 20 and the valve passage 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. has. The ring spring 6 has a plurality of spring pieces brought into contact with the outer periphery of the actuating rod 5 to apply a predetermined biasing force.

The valve body 3 is arranged within the valve chamber VS. When the valve body 3 is seated on the valve seat 20 of the valve body 2, the flow of refrigerant through the valve passage hole 27 is restricted. This state is called a non-communication state. However, even when the valve body 3 is seated on the valve seat 20, a limited amount of refrigerant may flow. On the other hand, when the valve body 3 is spaced apart from the valve seat 20, the flow of refrigerant passing through the valve passage hole 27 increases. This state is called a communication state.

The actuating rod 5 is inserted into the valve passage hole 27 with a predetermined 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 a fitting hole 84e of a stopper member 84, which will be described later.

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

In FIG. 1, the biasing device 4 includes a coil spring 41 made of a wire rod having a circular cross section wound helically, 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 the upper surface of the valve body support 42, so that the two are integrated.

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

Next, the power element 8 will be explained. FIG. 2 is a sectional view of the power element 8. The power element 8 includes a plug 81, a top cover member 82, a diaphragm 83, a receiving member 86, and a stopper member 84.

An opening 82 a is formed at the top of the substantially conical upper lid member 82 and can be sealed with a plug 81 .

The diaphragm 83 is made of a thin metal (for example, SUS) plate material with a plurality of concentric concave and convex shapes formed thereon, and has an outer diameter that is approximately the same as the outer diameter of the upper cover member 82 and the receiving member 86 .

The receiving member 86 is formed by press-forming a metal plate material, for example, and is connected to a flange portion 86a having an outer diameter that is approximately the same as the outer diameter of the flange portion 82b of the upper lid member 82, and to the center of the lower surface of the flange portion 86a. It has a hollow cylindrical portion 86b. A male thread 86c is formed on the outer periphery of the hollow cylindrical portion 86b.

The stopper member 84 has a circular upper plate 84a and a bottomed tub portion 84b, and the outer peripheral lower surface of the upper plate 84a and the upper surface of the upper end flange portion 84c of the tub portion 84b are connected by brazing, etc. It is joined by The thickness of the upper plate 84a is thinner than the side wall and bottom wall of the tub portion 84b, and the upper plate 84a is relatively easy to bend. The upper plate 84a is in contact with the center of the lower surface of the diaphragm 83 over a wide area, and its outer periphery extends above the flange portion 82b of the receiving member 86. A fitting hole 84e is formed in the center of the lower surface of the tub portion 84b.

A space formed between the upper plate 84a and the tub portion 84b is tightly filled with a temperature-sensitive material 84d (without air or the like coexisting inside). The temperature-sensitive material 84d changes from a solid phase to a liquid phase at the melting point, and has a characteristic that the coefficient of thermal expansion in the liquid state (above the melting point) is considerably larger than that in the solid state (below the melting point). have For example, an aliphatic compound whose melting point has been adjusted can be used as the temperature-sensitive material 84d. However, in order to lower the melting point, an alkane having less than 20 carbon atoms may be used as the temperature-sensitive material 84d, or the alkane may be added to paraffin having 20 or more carbon atoms. When a mixed material containing multiple types of aliphatic compounds is used as the temperature-sensitive material 84d, since the melting points of each compound are different, the coefficient of thermal expansion changes stepwise depending on the phase state of each compound in response to temperature changes. becomes.
The temperature-sensitive material 84d is adjusted so that the coefficient of thermal expansion above the predetermined temperature is greater than the coefficient of thermal expansion below the predetermined temperature. When the temperature-sensitive material 84d is composed of a single compound, the predetermined temperature coincides with the melting point of the compound. When the temperature-sensitive material 84d is a mixed material (composite material) as described above, the melting point of any one of the plurality of compounds constituting this mixed material coincides with the predetermined temperature, that is, one of the plurality of compounds It is preferable that the melting point changes between a solid state and a liquid state.

The procedure for assembling the power element 8 will be explained. The stopper member 84 is formed by assembling the upper plate 84a, the tub portion 84b, and the temperature-sensitive material 84d in advance. Further, the formed stopper member 84 is disposed between the diaphragm 83 and the receiving member 86, and the outer peripheral portions of the upper lid member 82, the diaphragm 83, and the receiving member 86 are overlapped. Then, the outer circumferential portion is circumferentially welded, for example, by TIG welding, laser welding, plasma welding, etc., and is integrated.

Subsequently, after sealing a working gas into a space (referred to as a sensitive chamber or pressure-operated chamber PO) surrounded by the upper lid member 82 and the diaphragm 83 through an opening 82a formed in the upper lid member 82, the opening 82a is closed with a stopper 81. After sealing, the plug 81 is fixed to the upper lid member 82 using projection welding or the like.

At this time, the diaphragm 83 receives pressure from the working gas sealed in the pressure working chamber PO in a manner that it protrudes toward the receiving member 86. Therefore, a stopper disposed in the lower space LS surrounded by the diaphragm 83 and the receiving member 86 The member 84 is supported by coming into contact with the upper surface of the upper plate 84a.

When assembling the power element 8 assembled as described above to the valve body 2, the male thread 86c on the outer periphery of the lower end of the hollow cylindrical portion 86b of the receiving member 86 is inserted into the recess 2a communicating with the return passage 23 of the valve body 2. It is screwed into the female thread 2b formed on the inner periphery. When the male thread 86c of the hollow cylindrical portion 86b is threaded toward the female thread 2b, the receiving member 86 comes into contact with 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, a packing PK is interposed between the power element 8 and the valve body 2 to prevent leakage of refrigerant 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, that is, has the same internal pressure.

(Operation of expansion valve)
An example of the operation of the expansion valve 1 will be described with reference to FIG. The refrigerant pressurized by the compressor 101 is liquefied by the condenser 102 and sent to the expansion valve 1. Further, the refrigerant that has been adiabatically expanded by the expansion valve 1 is sent to the evaporator 104, where it exchanges heat with the air flowing around the evaporator. The refrigerant returning from the evaporator 104 passes through the expansion valve 1 (more specifically, the return passage 23) and is returned to the compressor 101 side. 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.

High-pressure refrigerant is supplied to the expansion valve 1 from a 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), it is sent from the valve chamber VS to the evaporator 104 through the valve passage hole 27, the intermediate chamber 221, and the second flow path 22. Refrigerant flow is restricted. On the other hand, when the valve body 3 is separated from the valve seat 20 (in the communicating state), water flows from the valve chamber VS to the evaporator 104 through the valve passage hole 27, the intermediate chamber 221, and the second flow path 22. The flow rate of refrigerant delivered increases. Switching of the expansion valve 1 between the closed state and the open state is performed by the actuation 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 operating chamber PO and a lower space LS partitioned by a diaphragm 83. Therefore, when the working gas in the pressure working chamber PO is liquefied, the diaphragm 83 and the stopper member 84 rise, and the working rod 5 moves upward according 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, so the operating rod 5 moves downward. In this way, the expansion valve 1 is switched between the open state and the closed state.

Furthermore, the lower space LS of the power element 8 communicates with the return flow path 23. Therefore, the volume of the working gas in the pressure working chamber PO changes depending on the temperature and pressure of the refrigerant flowing through the return passage 23, and the working rod 5 is driven. In other words, in the expansion valve 1 shown in FIG. be adjusted.

FIG. 3 is a graph showing the opening pressure characteristics of the expansion valve 1, where the horizontal axis is the temperature of the power element, and the vertical axis is the refrigerant pressure in the lower space LS. In FIG. 3, the saturation curve of refrigerant gas is shown by a dotted line A, and the valve opening characteristic of the expansion valve 1 according to this embodiment is shown by a solid line B. Further, as a reference, the opening characteristic (straight charge) of an expansion valve (comparative example 1) used in a refrigeration cycle using a fixed capacity compressor is shown by a two-dot chain line C. Further, a chain line D indicates the opening characteristic (cross charge) of an expansion valve (Comparative Example 2) used in a refrigeration cycle using a variable capacity compressor. The upper part of each curve is the valve-closing region, and the lower part is the valve-opening region. Note that in a region lower than the cross point E (15° C.), the solid line B and the dashed-dotted line D overlap.

Here, when the evaporation pressure is 0.5 MPaG, the differences SH3deg, SH5deg, and SH10deg between the working gas saturation curve (dotted line A) and the curves of each valve opening characteristic are the static superheat degree (valve opening The degree of superheat required for

First, in the cross-charge valve opening characteristic shown by the dashed-dotted line D, the valve-opening region is expanded compared to the straight-charge valve opening characteristic shown by the double-dotted line C in the range where the refrigerant is at a low temperature (for example, below 17°C). In other words, the valve is easy to open even at low temperatures. Therefore, it can be seen that the cross-charge valve opening characteristic is suitable for the refrigeration cycle of a variable capacity compressor because the refrigerant can be circulated even in a low load region.

However, since the cross-charge valve opening characteristic shown by the dashed-dotted line D has a gentle slope, the valve-opening characteristic of the straight charge shown by the double-dashed line C does not change in the range where the refrigerant reaches a high temperature (for example, 17°C or higher). Compared to this, the valve opening area is narrower, which means the valve can be closed more easily. For this reason, it can be said that the compressor tends to overheat and reduce efficiency on the high temperature side.

On the other hand, the opening characteristic of the expansion valve 1 of this embodiment shown by the solid line B is the same as the opening characteristic of the cross charge shown by the dashed line D in the low temperature range below the cross point E (15°C). Has valve opening characteristics. On the other hand, according to the opening characteristic of the expansion valve 1 of the present embodiment, the static superheat degree is smaller than the opening characteristic of the cross charge shown by the dashed line D in the high temperature range above the cross point E (15° C.). (SH5deg), which is close to the valve opening characteristic of the straight charge shown by the two-dot chain line C. That is, the expansion valve 1 of this embodiment is suitable for the refrigeration cycle of a variable capacity compressor on the low load side, and can suppress overheating of the compressor on the high load side, thereby achieving improved efficiency.

A mechanism for realizing such a valve-opening characteristic of the expansion valve 1 of this embodiment will be described. The working gas pressure in the pressure working chamber PO of the power element 8 is _PE , the pressure receiving area (effective area) of the diaphragm 83 is A, the refrigerant pressure in the lower space LS is P _L , and the biasing force of the coil spring 41 is F. _S , the following equation (1) holds true when the expansion valve 1 is in a balanced state.
P _E ×A=P _L ×A+F _S (1)

Here, it is assumed that the working gas has cross-charge valve opening characteristics. Further, at a temperature below the cross point E, the temperature sensitive material 84d of the stopper member 84 is in a solid state. When the expansion valve 1 is in the closed state and refrigerant is sucked by the drive of the compressor 101, the refrigerant pressure P _L decreases and the degree of superheat increases at the outlet of the evaporator 104 to which refrigerant is not supplied. The working gas pressure _PE increases due to heat transfer. Then, since the value on the left side of equation (1) becomes larger than the value on the right side, the balanced state is disrupted and the valve is opened. Therefore, the same valve opening characteristics as cross charge can be obtained at a temperature below cross point E.

On the other hand, when the temperature-sensitive material 84d of the stopper member 84 melts into a liquid state at a temperature equal to or higher than the cross point E, the volume expands in accordance with the temperature. At this time, the upper plate 84a is deformed to swell upward (in the direction along the driving force transmission path) according to the expanded volume of the temperature-sensitive material 84d, thereby pushing up the diaphragm 83 and pushing down the actuating rod 5. . As a result, the total length of the parts arranged in the driving force transmission path between the diaphragm 83 and the valve body 3 changes, so as shown by the solid line B in FIG. It is possible to obtain a valve opening characteristic different from that of the above. That is, in this embodiment, the predetermined temperature at which the temperature-sensitive material 84d changes from a low expansion coefficient to a high expansion coefficient is adjusted to match the temperature of the cross point E or its vicinity.

(First modification)
FIG. 4 is an enlarged cross-sectional view showing a power element 8A according to a first modification example attached to the valve body 2. As shown in FIG. In this modification, an expandable component 85 containing a temperature-sensitive material is disposed between the stopper member 84A and the actuating rod 5. The stopper member 84A is formed by press-molding a metal plate material into a dish shape, and is arranged so that its outer periphery extends above the flange portion 82b of the receiving member 86.

The inflatable component 85 includes an upper tub member 85a, a lower tub member 85b, and a temperature sensitive material 85c. The temperature sensitive material 85c can be formed from the same material as the temperature sensitive material 84d of the embodiment described above. The upper tub member 85a and the lower tub member 85b can each be formed by press-molding metal plates. Further, a fitting hole 85f, into which the upper end of the actuating rod 5 engages, is formed at the center of the lower surface of the lower tub member 85b.

The expandable component 85 is joined by a method such as brazing by making the flange portion 85d of the upper tub member 85a and the flange portion 85e of the lower tub member 85b face each other so as to butt each other, with the temperature-sensitive material 85c interposed therebetween. be done. As a result, the temperature-sensitive material 85c is sealed in the space formed between the upper tub member 85a and the lower tub member 85b without air or the like coexisting therein. Since the other configurations are the same as those of the embodiment described above, the same reference numerals are given and redundant explanation will be omitted.

When assembling the power element 8A, the formed stopper member 84A and the expandable component 85 are placed in an overlapping manner between the diaphragm 83 and the receiving member 86. Then, the outer peripheral portions of the upper lid member 82, the diaphragm 83, and the receiving member 86 are overlapped, and the overlapping portions are circumferentially welded to be integrated.

In this modification, the upper tub member 85a and the lower tub member 85b each have a uniform wall thickness, but the joined flange portions 85d and 85e increase the rigidity of the side surface of the inflatable component 85. Therefore, when the temperature-sensitive material 85c expands, the upper wall of the upper tub member 85a and the lower wall of the lower tub member 85b are relatively largely deformed in the direction of the driving force transmission path, and the actuating rod 5 can be displaced downward. .

(Second modification)
FIG. 5 is an enlarged sectional view showing a power element 8B according to a second modification example attached to the valve body 2. As shown in FIG. In this modification, the stopper member 84B includes a circular flange portion 84Ba and a cylindrical main body 84Bb, and a fitting hole 84Bc into which the upper end of the actuating rod 5B fits is formed in the center lower surface of the main body 84Bb. ing.

A cylindrical blind hole 5Ba extending in the axial direction is formed at the upper end of the actuating rod 5B, and the temperature-sensitive material 52 is sealed inside the blind hole 5Ba in the absence of air or the like. The temperature-sensitive material 52 can be made of the same material as the temperature-sensitive material 84d of the embodiment described above. A cylindrical plug 51 is inserted into the upper end of the blind hole 5Ba. A circumferential groove 51a is formed in the central outer periphery of the plug 51, and an O-ring OR is disposed inside the circumferential groove 51a. The O-ring OR seals the gap between the plug 51 and the blind hole 5Ba. Since the other configurations are the same as those of the embodiment described above, the same reference numerals are given and redundant explanation will be omitted.

When the temperature-sensitive material 52 is in a solid state, the upper end surface of the plug 51 is at the same level as the upper end of the actuating rod 5B, or slightly protrudes, and is in contact with the lower surface of the stopper member 84B. On the other hand, when the temperature-sensitive material 52 becomes liquid and expands in volume, the O-ring OR seals liquid leakage, increasing the internal pressure in the blind hole 5Ba, pushing the plug 51 upward from the blind hole 5Ba. It begins to protrude. As a result, the entire length of the actuating rod 5B is extended, so that a pressing force is transmitted to the diaphragm 83 via the stopper member 84B, and the reaction force acts to push down the actuating rod 5B against the bias of the coil spring 41.

Note that the present invention is not limited to the above-described embodiments. Variations in any of the components of the embodiments described above are possible within the scope of the invention. Moreover, any component can be added or omitted in the embodiments described above. For example, any two or more of the present embodiment, the first modification, and the second modification may be used in combination.

1: Expansion valve 2: Valve body 3: Valve body 4: Biasing device 5, 5B: Operating rod 6: Ring spring 8, 8A, 8B: Power element 20: Valve seat 21: First flow path 22: Second flow Channel 221: Intermediate chamber 23: Return passage 27: Valve hole 28: Operating rod insertion hole 29: Annular recess 41: Coil spring 42: Valve body support 43: Spring receiving member 81: Plug 82: Top cover member 83: Diaphragm 84 , 84A, 84B: Stopper member 85: Expandable component 86: Receiving member 100: Refrigerant circulation system 101: Compressor 102: Condenser 104: Evaporator VS: Valve chamber

Claims (6)

a valve body disposed within a flow path through which fluid passes and having a valve seat;
a valve body that restricts or allows passage of the fluid through the valve seat by moving toward or away from the valve seat;
a coil spring that urges the valve body toward the valve seat;
an actuating rod having one end in contact with the valve body;
a power element that drives the actuating rod;
The power element includes an upper lid member, a diaphragm, a receiving member disposed on a side opposite to the upper lid member across the diaphragm, and a stopper member disposed between the diaphragm and the actuation rod. Prepare,
When the diaphragm presses the stopper member toward the valve body, driving force is transmitted from the stopper member to the valve body via the actuation rod,
A temperature-sensitive material having a larger coefficient of thermal expansion above the predetermined temperature than below the predetermined temperature is arranged in a component disposed in the driving force transmission path between the diaphragm and the valve body.
An expansion valve characterized by: The component is the stopper member that includes the temperature-sensitive material and is deformable according to expansion of the temperature-sensitive material.
The expansion valve according to claim 1, characterized in that: The component is the actuation rod that includes the temperature-sensitive material and is deformable according to expansion of the temperature-sensitive material.
The expansion valve according to claim 1, characterized in that: The component is disposed between the stopper member and the actuation rod, includes the temperature-sensitive material, and is deformable according to expansion of the temperature-sensitive material.
The expansion valve according to claim 1, characterized in that: The temperature-sensitive material changes between a solid state and a liquid state at the predetermined temperature.
The expansion valve according to any one of claims 1 to 4, characterized in that: The temperature-sensitive material is a composite material made of multiple types of compounds, and one of the multiple types of compounds changes between a solid state and a liquid state at the predetermined temperature.
The expansion valve according to claim 5, characterized in that:

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