EP4063766A1

EP4063766A1 - Expansion valve

Info

Publication number: EP4063766A1
Application number: EP22163145.0A
Authority: EP
Inventors: Junya Hayakawa; Ryo Matsuda
Original assignee: Fujikoki Corp
Current assignee: Fujikoki Corp
Priority date: 2021-03-25
Filing date: 2022-03-21
Publication date: 2022-09-28
Also published as: JP7403168B2; JP2022149022A; CN115127259A; JP2023153226A

Abstract

Provided is an expansion valve capable of realizing appropriate refrigeration cycle control while being capable of connecting to a double pipe. The expansion valve is capable of connecting to a double pipe in which a low-pressure refrigerant passes through an inner pipe and a high-pressure refrigerant passes between the inner pipe and an outer pipe disposed around the inner pipe. The expansion valve comprises a valve main body including a low-pressure flow path through which the low-pressure refrigerant flows and a high-pressure flow path through which the high-pressure refrigerant flows; a power element attached to the valve main body; and a heat transfer control portion that suppresses heat transfer between the power element and the high-pressure refrigerant flowing in the outer pipe by connecting the outer pipe to the valve main body eccentrically in a direction that separates from the power element further than the inner pipe.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to Japanese Patent Application No. 2021-050942, filed March 25, 2021 . The contents of this application are incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

The present invention relates to an expansion valve.

SUMMARY OF THE INVENTION

Conventionally, in the refrigeration cycles used in air conditioners or the like mounted in automobiles, temperature-sensitive expansion valves are used that adjust the amount of refrigerant passing through according to the temperature.
These expansion valves are equipped with a drive mechanism for a valve member, referred to as a power element, that encloses a pressure working chamber. A valve element disposed in the valve chamber and the power element are connected by an operation rod, the operation rod is driven by the pressure change of the gas sealed in the pressure working chamber, and thereby the opening and closing operations of the valve element are carried out. Since the gas pressure in the pressure working chamber changes according to the balance between the heat transferred from the outside of the power element and the heat transferred to the refrigerant, the valve element opens and closes autonomously, and the refrigeration cycle is automatically controlled.
Generally, a high-pressure pipe in which the refrigerant is sent from the condenser of the refrigeration cycle and a low-pressure pipe in which the refrigerant is sent from the evaporator are separately connected to an expansion valve. In contrast, in the expansion valve disclosed in Japanese Unexamined Patent Application Publication No. 2020-94793 (Patent Document 1), a system is disclosed in which a double pipe having a low-pressure pipe as an inner pipe and a high-pressure pipe as an outer pipe is connected to an expansion valve. According to such a system, it is possible to simplify the routing of the piping.
In the expansion valve disclosed in Patent Document 1, a relatively high temperature refrigerant sent from the condenser flows between the outer pipe and the inner pipe, but the outer pipe is disposed in the vicinity of the power element. Accordingly, in addition to the heat received by the power element from the atmosphere, the heat generated from the refrigerant flowing between the outer pipe and the inner pipe is also transferred to the power element, which increases the gas pressure in the pressure working chamber, and may cause premature valve opening or other improper control of the refrigeration cycle.
Accordingly, an object of the present invention is to provide an expansion valve capable of realizing appropriate refrigeration cycle control while being capable of connecting to a double pipe.
In order to achieve the above object, the expansion valve according to the present invention is an expansion valve capable of connecting to a double pipe in which a low-pressure refrigerant passes through an inner pipe and a high-pressure refrigerant passes between the inner pipe and an outer pipe disposed around the inner pipe, the expansion valve comprising: a valve main body including a low-pressure flow path through which the low-pressure refrigerant flows and a high-pressure flow path through which the high-pressure refrigerant flows; a power element attached to the valve main body; and a heat transfer control portion that suppresses heat transfer between the power element and the high-pressure refrigerant flowing in the outer pipe by connecting the outer pipe to the valve main body eccentrically in a direction that separates from the power element further than the inner pipe.
According to the present invention, it is possible to provide an expansion valve capable of realizing appropriate refrigeration cycle control while being capable of connecting to a double pipe.

BRIEF DESCRIPTION OF THE DRAWINGS

[Figure 1] FIG. 1 is a schematic cross-sectional view schematically illustrating an example in which the expansion valve according to the present embodiments is applied to a refrigerant circulation system.
[Figure 2] FIG. 2 is a perspective view illustrating the valve main body according to the present embodiments divided in half.
[Figure 3] FIG. 3 is a vertical cross-sectional view of the expansion valve according to a second embodiment.
[Figure 4] FIG. 4 is a vertical cross-sectional view of the expansion valve according to a third embodiment.
[Figure 5] FIG. 5 is a vertical cross-sectional view of the expansion valve according to a fourth embodiment.
[Figure 6] FIG. 6 is a vertical cross-sectional view of the expansion valve according to a fifth embodiment.
[Figure 7] FIG. 7 is a side view of a return flow path of the present embodiments from the right side of FIG. 6.
[Figure 8] FIG. 8 is a vertical cross-sectional view of the expansion valve according to a sixth embodiment.
[Figure 9] FIG. 9 is a side view of a return flow path of the present embodiments from the right side of FIG. 8.
[Figure 10] FIG. 10 is a vertical cross-sectional view of the expansion valve according to a seventh embodiment.
[Figure 11] FIG. 11 is a vertical cross-sectional view of an expansion valve according to an eighth embodiment.
[Figure 12] FIG. 12 is a perspective view illustrating the valve main body according to the present embodiments divided in half together with a ring member.

DETAILED DESCRIPTION

Hereinafter, the embodiments according to the present invention will be described with reference to the figures.

(Definition of Directions)

In the present specification, the direction extending from the valve element 3 toward the operation rod 5 is defined as the "upward direction," and the direction extending from the operation rod 5 toward the valve element 3 is defined as the "downward direction." Accordingly, in the present specification, the direction extending from the valve element 3 toward the operation rod 5 is referred to as the "upward direction" regardless of the orientation of the expansion valve 1.
Further, in the present specification, in addition to including relationships in which two or more axes completely align, "coaxial" includes relationships in which two or more axes do not completely align but generally align. Similarly, "eccentric" refers to a relationship in which one center or axis is biased (shifted) in a certain direction with respect to another center or axis. Neither "coaxial" or "eccentric," which both refer to the relationship between axes, nor the parallelism between axes is limited to a relationship that completely aligns.

(First Embodiment)

An overview of the expansion valve 1 according to the present embodiments will be described with reference to FIG. 1 and FIG. 2. FIG. 1 is a schematic cross-sectional view schematically illustrating an example in which the expansion valve 1 according to the present embodiments is applied to a refrigerant circulation system 100. FIG. 2 is a perspective view illustrating the valve main body 2 according to the present embodiments divided in half.
In the present embodiment, the expansion valve 1 is fluidly connected to a compressor 101, a condenser 102, and an evaporator 104. L is set as the axis of the expansion valve 1.
In FIG. 1, the expansion valve 1 includes a valve main body 2 having a valve chamber VS, a valve element 3, a biasing device 4, an operation rod 5, and a power element 8.
The valve main body 2 includes a first flow path 21 (also referred to as a high-pressure flow path), 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 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 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 through a valve through-hole 27, the intermediate chamber 221 and the discharge-side flow path. A pipe (not illustrated in the figure) connected to the inlet side of the evaporator 104 is connected to the second flow path 22.
The return flow path 23 extends orthogonally to the axis L and penetrates the valve main body 2. Let O be the axis of the return flow path 23. The return flow path 23 is formed by coaxially connecting an inlet path 23a to which a pipe (not illustrated in the figure) connected to the outlet side of the evaporator 104 is connected, an intermediate path (also referred to as a low-pressure flow path) 23b, a first enlarged diameter hole 23c having a diameter larger than that of the intermediate path 23b, a second enlarged diameter hole 23d having a diameter larger than that of the first enlarged diameter hole 23c, and a third enlarged diameter hole 23e having a diameter larger than that of the second enlarged diameter hole 23d. Although the details thereof will be described later, the intermediate path 23b communicates with the lower space LS of the power element 8 through the vertical hole 2a.
In the present embodiment, on the inner circumference of the intermediate path 23b, a plurality of (three in this case) circumferential grooves 2c are formed over the entire circumference between the vertical hole 2a and the first enlarged diameter hole 23c. The bottom diameter of the circumferential grooves 2c is preferably smaller than the inner diameter of the second enlarged diameter hole 23d. It is desirable that the inner pipe 51 and the circumferential grooves 2c do not interfere with each other. The circumferential groove 2c constitutes a heat transfer control portion.
A double pipe 50 is connected to the return flow path 23. The double pipe 50 includes an inner pipe 51 whose end portion fits with the intermediate path 23b, and an outer pipe 52 that includes the inner pipe 51 and whose end portion fits with the second enlarged diameter hole 23d. The inner pipe 51 has a flange portion 51a in the vicinity of its end portion that is formed by expanding a portion of the pipe and crushing it in the axial direction. An O-ring OR1 held by the flange portion 51a is disposed between the end portion of the inner pipe 51 and the flange portion 51a, thereby sealing the space between the first enlarged diameter hole 23c and the outer circumference of the inner pipe 51, and preventing refrigerant leakage.
In addition, the outer pipe 52 also has a flange portion 52a in the vicinity of its end portion that is formed by expanding a portion of the pipe and crushing it in the axial direction. The end portion of the outer pipe 52 does not have a bottom at the step portion of the second enlarged diameter hole 23d, and the flange portion 52a is in contact with the side surface of the valve main body 2. An O-ring OR2 held by the flange portion 52a is disposed between the end portion of the outer pipe 52 and the flange portion 52a, thereby sealing the space between the third enlarged diameter hole 23e and the outer circumference of the outer pipe 52, and preventing refrigerant leakage.
Inner pipe 51 is connected to the inlet of the compressor 101, and the annular space between the outer pipe 52 and the inner pipe 51 is connected to the outlet of the condenser 102.
The first flow path 21 has an axis in a plane including the axis L and the axis O, and is inclined with respect to the axis L and the axis O. In addition, the upper end of the first flow path 21 is open at the inner circumference of the second enlarged diameter hole 23d, and the lower end of the first flow path 21 is open at the inner circumference of the valve chamber VS below the valve seat 20. That is, the inside of the second enlarged diameter hole 23d and the valve chamber VS communicate with each other via the first flow path 21. In addition, the valve chamber VS and the intermediate chamber 221 communicate with each other via the valve seat 20 and the valve through-hole 27.
The operation rod insertion hole 28 formed above the intermediate chamber 221 has a function for guiding the operation rod 5, and the annular recess 29 formed above the operation rod insertion hole 28 has a function of accommodating a ring spring 6. The ring spring 6 applies a predetermined biasing force by coming into contact with a plurality of spring on the outer circumference of the operation rod 5.
The valve element 3 is arranged in the valve chamber VS. When the valve element 3 is seated on the valve seat 20 of the valve main body 2, the flow of the refrigerant through the valve through-hole 27 is restricted. This state is referred to as a non-communicating state. However, even in the case that the valve element 3 is seated on the valve seat 20, a limited amount of refrigerant may flow. On the other hand, when the valve element 3 is separated from the valve seat 20, the flow of the refrigerant passing through the valve through-hole 27 increases. This state is referred to as a communication state.
The operation rod 5 is inserted into the valve through-hole 27 with a predetermined gap. The lower end of the operation rod 5 is in contact with the upper surface of the valve element 3. The upper end of the operation rod 5 is fitted into a fitting hole 84c of the stopper member 84.
The operation rod 5 can press the valve element 3 in a valve opening direction against the biasing force of the biasing device 4. When the operation rod 5 moves downward, the valve element 3 is separated from the valve seat 20 and the expansion valve 1 is opened.
The biasing device 4 includes a coil spring 41 in which a wire member having a circular cross section is spirally wound, a valve element support 42, and a spring receiving member 43.
The valve element support 42 is attached to the upper end of the coil spring 41, a spherical valve element 3 is welded to the upper surface thereof, and both are integrated together.
The spring receiving member 43 that supports the lower end of the coil spring 41 can be screwed against the valve main body 2, and has a function of sealing the valve chamber VS and a function of adjusting the biasing force of the coil spring 41.
The power element 8 includes a plug 81, an upper lid member 82, a diaphragm 83, a receiving member 86, and a stopper member 84.
An opening is formed at the top of the substantially conical upper lid member 82, and can be sealed by the plug 81.
The diaphragm 83 is made of a thin metal (SUS, for example) plate material in which a plurality of concentric, uneven shapes are formed, and has an outer diameter substantially the same as the outer diameter of the upper lid member 82 and the receiving member 86.
The receiving member 86 is formed by, for example, press-molding a metal plate material, and is constituted by connecting the flange portion and the hollow cylindrical portion.
The stopper member 84 is disposed between the upper lid member 82 and the receiving member 86, and its upper surface is in contact with the center of the lower surface of the diaphragm 83.
In the assembly of the power element 8, while arranging the stopper member 84 between the diaphragm 83 and the receiving member 86, the outer circumferential portions of the upper lid member 82, the diaphragm 83, and the receiving member 86 are overlapped with each other, and the outer circumferential portions are circumferentially welded by, for example, TIG welding, laser welding, plasma welding, or the like to integrate them.
Subsequently, the working gas is sealed in the space (referred to as the pressure working chamber PO) surrounded by the upper lid member 82 and the diaphragm 83 from the opening formed in the upper lid member 82, and then the opening is sealed with the plug 81. Further, the plug 81 is fixed to the upper lid member 82 by projection welding or the like.
When the power element 8 assembled as described above is attached to the valve main body 2, the male screw 86a on the outer circumference of the lower end of the hollow cylindrical portion of the receiving member 86 is screwed into the female screw 2b formed on the inner circumference of the vertical hole 2a communicating with the return flow path 23 of the valve main body 2. As the male screw of the receiving member 86 is screwed into the female screw 2b, the lower surface of the flange portion of the receiving member 86 comes into contact with the upper end surface of the valve main body 2. As a result, the power element 8 can be fixed to the valve main body 2.
At this time, a packing PK is interposed between the power element 8 and the valve main body 2 to prevent the refrigerant from leaking when the power element 8 is attached to the valve main body 2. In such a state, the lower space LS of the power element 8 communicates with the return flow path 23 through the vertical hole 2a.

(Operation of Expansion Valve)

An example of the operation of the expansion valve 1 will be described with reference to FIG. 1. The high-pressure refrigerant pressurized by the compressor 101 is liquefied by the condenser 102 and sent to the expansion valve 1. Further, the refrigerant adiabatically expanded by the expansion valve 1 is sent to the evaporator 104, and the evaporator 104 exchanges heat with the air flowing around the evaporator. The refrigerant returning from the evaporator 104 enters the return flow path 23 of the expansion valve 1, and returns to the compressor 101 side through the inner pipe 51 of the double pipe 50. At this time, as the refrigerant passes through the evaporator 104, the fluid pressure in the return flow path 23 becomes lower than the fluid pressure in the second flow path 22. The refrigerant that has passed through the evaporator 104 is referred to as low-pressure refrigerant.
The low-pressure refrigerant is sent from the expansion valve 1 to the compressor 101, and the high-pressure refrigerant is sent from the condenser 102 to the expansion valve 1. More specifically, the high-pressure refrigerant from the condenser 102 is supplied to the valve chamber VS between the outer pipe 52 and the inner pipe 51 of the double pipe 50 and via the first flow path 21.
When the valve element 3 is seated on the valve seat 20 (when in the non-communicating state), the flow rate of the refrigerant sent from the valve chamber VS to the evaporator 104 through the valve through-hole 27, the intermediate chamber 221 and the second flow path 22 is limited. On the other hand, when the valve element 3 is separated from the valve seat 20 (when in the communicating state), the flow rate of the refrigerant sent from the valve chamber VS to the evaporator 104 through the valve through-hole 27, the intermediate chamber 221 and the second flow path 22 increases. Switching between the closed state and the open state of the expansion valve 1 is performed by the operation rod 5 connected to the power element 8 via the stopper member 84.
In FIG. 1, a pressure working chamber PO and a lower space LS partitioned by a diaphragm 83 are provided inside the power element 8. Accordingly, when the working gas in the pressure working chamber PO is liquefied, the diaphragm 83 and the stopper member 84 rise, such that the operation 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, such that the operation rod 5 moves downward. In this way, the expansion valve 1 is switched between an open state and a closed state.
Further, the lower space LS of the power element 8 communicates with the return flow path 23 via the vertical hole 2a. Accordingly, the volume of the working gas in the pressure working chamber PO changes according to the temperature and pressure of the refrigerant flowing through the return flow path 23, and the operation rod 5 is driven. In other words, in the expansion valve 1 illustrated in FIG. 1, the amount of the refrigerant supplied from the expansion valve 1 toward the evaporator 104 is automatically adjusted according to the temperature and pressure of the refrigerant returning from the evaporator 104 to the expansion valve 1.
As described above, the high-pressure refrigerant having a temperature higher than the atmospheric temperature is sent to the second enlarged diameter hole 23d between the outer pipe 52 and the inner pipe 51 of the double pipe 50. At this time, when the heat of the high-pressure refrigerant is transmitted from the inner wall of the second enlarged diameter hole 23d to the power element 8 through the inside of the valve main body 2, the working gas in the pressure working chamber PO is affected, and there is a risk that a pressure different from the case where only heat from the atmosphere is transferred to the power element 8 will be created in the pressure working chamber PO.
In contrast, according to the present embodiment, since the circumferential groove 2c is formed on the inner circumference of the intermediate path 23b between the vertical hole 2a and the second enlarged diameter hole 23d, the relatively low temperature refrigerant that has entered the intermediate path 23b enters the circumferential groove 2c. As a result, heat transfer from the bottom wall and side wall of the circumferential groove 2c to the refrigerant can be promoted, so that the amount of heat transferred from the second enlarged diameter hole 23d to the power element 8 can be reduced. That is, by arranging the circumferential groove 2c to expand the heat exchange area in the intermediate path 23b, it is possible to suppress the influence of the heat of the high-pressure refrigerant passing through the second enlarged diameter hole 23d, and to realize appropriate control operations of the power element 8.
The expansion valve according to the present invention is an expansion valve capable of connecting to a double pipe in which a low-pressure refrigerant passes through an inner pipe and a high-pressure refrigerant passes between the inner pipe and an outer pipe disposed around the inner pipe, the expansion valve including: a valve main body including a low-pressure flow path through which the low-pressure refrigerant flows and a high-pressure flow path through which the high-pressure refrigerant flows; a power element attached to the valve main body; and a heat transfer control portion that suppresses heat transfer between the power element and the high-pressure refrigerant flowing in the outer pipe by connecting the outer pipe to the valve main body eccentrically in a direction that separates from the power element further than the inner pipe, wherein the heat transfer control portion is a groove provided in the low-pressure flow path.

(Second Embodiment)

FIG. 3 is a vertical cross-sectional view of the expansion valve 1A according to the second embodiment. The present embodiment differs from the first embodiment only in the configuration of the valve main body 2A. The rest of the configuration is the same as that of the above-described embodiment, and therefore, the same reference numerals are assigned and a repetitive description thereof is omitted.
The valve main body 2A of the present embodiment has an annular wall 2Ac protruding inward in the radial direction instead of disposing a circumferential groove in the intermediate path 23b. When performing a cutting process on the return flow path 23a from both sides, the annular wall 2Ac can be formed integrally with the valve main body 2A by adjusting the driving amount of the tool to leave a portion of the valve main body 2A. However, an annular wall 2Ac having an outer diameter equal to the inner diameter of the intermediate path 23b may be formed by a separate member and further fitted and fixed to the intermediate path 23b by press fitting or the like. The annular wall 2Ac constitutes a heat transfer control portion.
According to the present embodiment, a portion of the refrigerant that enters the return flow path 23A passes through the inside of the annular wall 2Ac and flows into the inner pipe 51, and at that time, heat transfer to the refrigerant can be promoted through the surface of the annular wall 2Ac. On the other hand, the rest of the refrigerant comes into contact with the annular wall 2Ac and returns, enters the vertical hole 2a, and promotes heat transfer from the stopper member 84. That is, the heat exchange area in the intermediate path 23b can be expanded by disposing the annular wall 2Ac, and the amount of heat transferred from the second enlarged diameter hole 23d to the power element 8 can be reduced by changing the flow of the refrigerant. Accordingly, it is possible to suppress the influence of the heat of the high-pressure refrigerant passing through the second enlarged diameter hole 23d, and to realize appropriate control operations of the power element 8.
The expansion valve according to the present invention is an expansion valve capable of connecting to a double pipe in which a low-pressure refrigerant passes through an inner pipe and a high-pressure refrigerant passes between the inner pipe and an outer pipe disposed around the inner pipe, the expansion valve including: a valve main body including a low-pressure flow path through which the low-pressure refrigerant flows and a high-pressure flow path through which the high-pressure refrigerant flows; a power element attached to the valve main body; and a heat transfer control portion that suppresses heat transfer between the power element and the high-pressure refrigerant flowing in the outer pipe by connecting the outer pipe to the valve main body eccentrically in a direction that separates from the power element further than the inner pipe, wherein the heat transfer control portion is a wall provided in the low-pressure flow path.

(Third Embodiment)

FIG. 4 is a vertical cross-sectional view of the expansion valve 1B according to the third embodiment. The present embodiment differs from the first embodiment only in the configuration of the valve main body 2B. The rest of the configuration is the same as that of the above-described embodiment, and therefore, the same reference numerals are assigned and a repetitive description thereof is omitted.
The valve main body 2B of the present embodiment has a bag hole 2Bc inclined with respect to the axis O instead of disposing a circumferential groove in the intermediate path 23b. Since the axis of the bag hole 2Bc does not intersect the inner circumference of the return flow path 23B and passes outside in the axial direction of the inlet path 23a, the bag hole 2Bc can be formed by a cutting process using a tool such as a drill inserted diagonally into the return flow path 23B. However, the bag hole 2Bc may be formed by drilling from the upper surface of the valve main body 2B to the intermediate path 23b and further sealing the outer end of the exposed hole with a plug or the like. The bag hole 2Bc constitutes a heat transfer control portion.
According to the present embodiment, the bag hole 2Bc is formed between the vertical hole 2a and the second enlarged diameter hole 23d so as to extend from the inner circumference of the intermediate path 23b toward the outer side in the radial direction of the second enlarged diameter hole 23d. Accordingly, a portion of the refrigerant flowing from the left side to the right side in the return flow path 23B easily enters the bag hole 2Bc, and as a result, heat transfer from the inner circumferential wall surface of the bag hole 2Bc to the refrigerant is promoted. That is, by arranging the bag hole 2Bc to expand the heat exchange area in the intermediate path 23b, since the amount of heat transferred from the second enlarged diameter hole 23d to the power element 8 can be reduced, it is possible to suppress the influence of the heat of the high-pressure refrigerant passing through the second enlarged diameter hole 23d, and to realize appropriate control operations of the power element 8.
The expansion valve according to the present invention is an expansion valve capable of connecting to a double pipe in which a low-pressure refrigerant passes through an inner pipe and a high-pressure refrigerant passes between the inner pipe and an outer pipe disposed around the inner pipe, the expansion valve including: a valve main body including a low-pressure flow path through which the low-pressure refrigerant flows and a high-pressure flow path through which the high-pressure refrigerant flows; a power element attached to the valve main body; and a heat transfer control portion that suppresses heat transfer between the power element and the high-pressure refrigerant flowing in the outer pipe by connecting the outer pipe to the valve main body eccentrically in a direction that separates from the power element further than the inner pipe, wherein the heat transfer control portion is a hole formed in the valve main body between the power element and the double pipe connected to the valve main body.

(Fourth Embodiment)

FIG. 5 is a vertical cross-sectional view of the expansion valve 1C according to the fourth embodiment. The present embodiment differs from the first embodiment only in the configuration of the valve main body 2C. The rest of the configuration is the same as that of the above-described embodiment, and therefore, the same reference numerals are assigned and a repetitive description thereof is omitted.
The valve main body 2C of the present embodiment is not provided with circumferential grooves in the intermediate path 23b. Instead, an annular groove 2Cc is formed on the upper end surface of the valve main body 2C around the vertical hole 2a. A portion of the annular groove 2Cc is located on the radial outer side of the first enlarged diameter hole 23c. The annular groove 2Cc constitutes a heat transfer control portion.
According to the present embodiment, since the annular groove 2Cc is formed on the radial outer side of the first enlarged diameter hole 23c between the vertical hole 2a and the second enlarged diameter hole 23d, the heat transfer path from the refrigerant that has entered the second enlarged diameter hole 23d to the power element 8 is narrowed, whereby the amount of heat transferred to the power element 8 can be reduced. Accordingly, it is possible to suppress the influence of the heat of the high-pressure refrigerant passing through the second enlarged diameter hole 23d, and to realize appropriate control operations of the power element 8.
The expansion valve according to the present invention is an expansion valve capable of connecting to a double pipe in which a low-pressure refrigerant passes through an inner pipe and a high-pressure refrigerant passes between the inner pipe and an outer pipe disposed around the inner pipe, the expansion valve including: a valve main body including a low-pressure flow path through which the low-pressure refrigerant flows and a high-pressure flow path through which the high-pressure refrigerant flows; a power element attached to the valve main body; and a heat transfer control portion that suppresses heat transfer between the power element and the high-pressure refrigerant flowing in the outer pipe by connecting the outer pipe to the valve main body eccentrically in a direction that separates from the power element further than the inner pipe, wherein the heat transfer control portion is a groove formed in the valve main body between the power element and the double pipe connected to the valve main body.

(Fifth Embodiment)

FIG. 6 is a vertical cross-sectional view of the expansion valve 1D according to the fifth embodiment. FIG. 7 is a side view of the return flow path 23D of the present embodiment from the right side of FIG. 6. The present embodiment differs from the first embodiment only in the shape of the return flow path 23D of the valve main body 2D. The rest of the configuration is the same as that of the above-described embodiments, and therefore, the same reference numerals are assigned and a repetitive description thereof is omitted.
In the valve main body 2D of the present embodiment, the second enlarged diameter hole 23Dd is divided into an eccentric hole (here, the third hole portion) 23D1 on the first enlarged diameter hole (here, the first hole portion) 23c side and a coaxial hole (here, the second hole portion) 23D2 on the third enlarged diameter hole 23e side. As illustrated in FIG. 6, the eccentric hole 23D1 having a diameter larger than that of the first enlarged diameter hole 23c is eccentric downward with respect to the first enlarged diameter hole 23c, but the coaxial hole 23D2 having a diameter larger than that of the eccentric hole 23D1 is coaxial with the first enlarged diameter hole 23c. Assuming that the axis of the first enlarged diameter hole 23c is O1 and the axis of the eccentric hole 23D1 is O2, the distance between the axes is Δ1. It is preferable that the location of the upper end of the first enlarged diameter hole 23c and the location of the upper end of the eccentric hole 23D1 coincide, and it is preferable that the location of the lower end of the eccentric hole 23D1 and the location of the lower end of the coaxial hole 23D2 coincide. The end portion of the inner pipe 51 fits with the intermediate path 23b, and the end portion of the outer pipe 52 fits with the coaxial hole 23D2. The eccentric hole 23D1 constitutes a heat transfer control portion.
The refrigerant supplied between the outer pipe 52 and the inner pipe 51 passes through the eccentric hole 23D1 and then continues to the first flow path 21. According to the present embodiment, since the eccentric hole 23D1 is shifted in a direction away from the power element 8, the amount of heat transferred from the refrigerant that has entered the eccentric hole 23D1 to the power element 8 can be reduced. As a result, it is possible to suppress the influence of the heat of the high-pressure refrigerant, and to realize appropriate control operations of the power element 8.

(Sixth Embodiment)

FIG. 8 is a vertical cross-sectional view of the expansion valve 1E according to the sixth embodiment. FIG. 9 is a side view of the return flow path 23E of the present embodiment from the right side of FIG. 8. The present embodiment differs from the first embodiment only in the configuration of the return flow path 23E of the valve main body 2E. The rest of the configuration is the same as that of the above-described embodiment, and therefore, the same reference numerals are assigned and a repetitive description thereof is omitted.
In the valve main body 2E of the present embodiment, the second enlarged diameter hole (here, the second hole portion) 23Ed and the third enlarged diameter hole 23Ee are eccentric downward with respect to the first enlarged diameter hole (here, the first hole portion) 23c. Assuming that the axis of the first enlarged diameter hole 23c is O1 and the axis of the second enlarged diameter hole 23Ed and the third enlarged diameter hole 23Ee is O3, the distance between the axes is Δ2. The inter-axis distance Δ2 is larger than the inter-axis distance Δ1 of the fifth embodiment. It is preferable that the location of the upper end portion of the first enlarged diameter hole 23c and the location of the upper end of the second enlarged diameter hole 23Ed coincide. The end portion of the inner pipe 51 is fitted in the intermediate path 23b, and the end portion of the outer pipe 52 is fitted in the second enlarged diameter hole 23Ed. Accordingly, the outer pipe 52 of the double pipe 50 is also eccentric downward with respect to the inner pipe 51. The second enlarged diameter hole 23Ed constitutes a heat transfer control portion.
The refrigerant supplied between the outer pipe 52 and the inner pipe 51 passes through the second enlarged diameter hole 23Ed and then continues to the first flow path 21. According to the present embodiment, since the second enlarged diameter hole 23Ed is further shifted in a direction away from the power element 8, the amount of heat transferred from the refrigerant that has entered the second enlarged diameter hole 23Ed to the power element 8 can be reduced. As a result, it is possible to suppress the influence of the heat of the high-pressure refrigerant, and to realize appropriate control operations of the power element 8.

(Seventh Embodiment)

FIG. 10 is a vertical cross-sectional view of the expansion valve 1F according to the seventh embodiment. In this embodiment, the valve main body 2D of the fifth embodiment is combined with a double pipe 50F different from the above-described embodiment. The rest of the configuration is the same as that of the above-described embodiment, and therefore, the same reference numerals are assigned and a repetitive description thereof is omitted.
The double pipe 50F has an inner pipe 51F and an outer pipe 52F. The outer pipe 52F has the same configuration as that of the above-described embodiments. On the other hand, the inner pipe 51F is formed by connecting a circular pipe portion 51Fb and a spiral portion 51Fc in series. A spiral groove 51Fd is formed on the outer circumference of the spiral portion 51Fc, and the outer circumferential surfaces other than the spiral groove 51Fd are cylindrical surfaces. The double pipe 50F constitutes a heat transfer control portion.
When the inner pipe 51F is inserted into the outer pipe 52F, the outer circumferential surface of the spiral portion 51Fc comes into contact with the inner circumferential surface of the outer pipe 52F, such that a spiral passage is formed along the spiral groove 51Fd. The high-pressure refrigerant will flow along this passage.
When the double pipe 50F is attached to the return flow path 23D of the valve main body 2D, the end portion of the outer pipe 52F fits into the coaxial hole 23D2, and the end portion of the inner pipe 51F protruding from the outer pipe 52F fits into the intermediate path 23b. The axis of the spiral portion 51Fc coincides with the axis O1 of the return flow path 23D, but the axis of the circular pipe portion 51Fb is eccentric upward. Accordingly, in the state of being attached to the valve main body 2D, the upper portion of the circular pipe portion 51Fb is in contact with the inner circumferential surface of the eccentric hole 23D1.
The refrigerant supplied between the outer pipe 52F and the inner pipe 51F passes through the spiral groove 51Fd, enters the lower side of the eccentric hole 23D1, and continues to the first flow path 21. At that time, heat is transferred from the high-pressure refrigerant passing through the spiral groove 51Fd to the low-pressure refrigerant passing through the inner pipe 51F. However, since the heat transfer area is increased by disposing the spiral groove 51Fd, heat transfer from the high-pressure refrigerant to the low-pressure refrigerant is promoted while passing through the spiral groove 51Fd. In addition, since the upper outer circumferential surface of the circular pipe portion 51b of the inner pipe 51F is in contact with the eccentric hole 23D1, the periphery of the upper part of the eccentric hole 23D1 is cooled by the refrigerant passing through the inner pipe 51F. Due to the above-described synergistic effect, the influence of the heat of the high-pressure refrigerant passing through the second enlarged diameter hole 23Fd can be suppressed, and appropriate control operations of the power element 8 can be realized.
The expansion valve according to the present invention is an expansion valve capable of connecting to a double pipe in which a low-pressure refrigerant passes through an inner pipe and a high-pressure refrigerant passes between the inner pipe and an outer pipe disposed around the inner pipe, the expansion valve including: a valve main body including a low-pressure flow path through which the low-pressure refrigerant flows and a high-pressure flow path through which the high-pressure refrigerant flows; a power element attached to the valve main body; and a heat transfer control portion that suppresses heat transfer between the power element and the high-pressure refrigerant flowing in the outer pipe by connecting the outer pipe to the valve main body eccentrically in a direction that separates from the power element further than the inner pipe, wherein the heat transfer control portion is a spiral groove formed around the inner pipe.

(Eighth Embodiment)

FIG. 11 is a vertical cross-sectional view of an expansion valve 1G according to the eighth embodiment. FIG. 12 is a perspective view illustrating the valve main body 2G according to the present embodiment divided in half together with the ring member 60. The present embodiment differs from the first embodiment only in that a circumferential groove is not formed in the return flow path 23G of the valve main body 2G and that a ring member 60 is arranged. The rest of the configuration is the same as that of the above-described embodiment, and therefore, the same reference numerals are assigned and a repetitive description thereof is omitted.
In the present embodiment, a resin ring member 60 is disposed so as to fit into the inner circumference of the second enlarged diameter hole (here, the second hole portion) 23d. A notch 60a is formed in a part of the ring member 60 in the circumferential direction. The ring member 60 is disposed in the second enlarged diameter hole 23d such that the notch 60a is aligned with the first flow path (the high-pressure flow path) 21. As a result, the entire inlet of the first flow path 21 is opened, and the inside of the ring member 60 in the radial direction and the first flow path 21 can communicate with each other through the notch 60a. An opening that communicates with the inner and outer circumferences of the ring member 60 may be provided instead of the notch 60a.
The inner circumferential surface of the ring member 60 comes into contact with the outer circumferential surface of the flange portion 51a of the inner pipe 51. The left end portion of the ring member 60 comes into contact with a step portion between the first enlarged diameter hole (here, the first hole portion) 23c and the second enlarged diameter hole 23d. The right end portion of the ring member 60 comes into contact with the end portion of the outer pipe 52. The wall thickness of the ring member 60 is preferably equal to the wall thickness of the outer pipe 52. The ring member 60 constitutes a heat transfer control portion.
The refrigerant supplied between the outer pipe 52 and the inner pipe 51 enters the second enlarged diameter hole 23d and then continues to the first flow path 21 through the notch 60a. According to the present embodiment, since the ring member 60 having heat insulating properties is disposed between the refrigerant that has entered the second enlarged diameter hole 23d and the second enlarged diameter hole 23d, the amount of heat transferred from the refrigerant that has entered the second enlarged diameter hole 23Ed to the power element 8 can be reduced. As a result, it is possible to suppress the influence of the heat of the high-pressure refrigerant, and to realize appropriate control operations of the power element 8. The ring member 60 can be used in combination with the above-described embodiments.
The expansion valve according to the present invention is an expansion valve capable of connecting to a double pipe in which a low-pressure refrigerant passes through an inner pipe and a high-pressure refrigerant passes between the inner pipe and an outer pipe disposed around the inner pipe, the expansion valve including: a valve main body including a low-pressure flow path through which the low-pressure refrigerant flows and a high-pressure flow path through which the high-pressure refrigerant flows; a power element attached to the valve main body; and a heat transfer control portion that suppresses heat transfer between the power element and the high-pressure refrigerant flowing in the outer pipe by connecting the outer pipe to the valve main body eccentrically in a direction that separates from the power element further than the inner pipe, wherein the valve main body includes: a first hole portion that is coaxial with the low-pressure flow path to which the inner pipe fits, and a second hole portion that communicates with the high-pressure flow path, is coaxial with the first hole portion, and fits with the outer pipe; and a ring member having heat insulating properties is disposed in the second hole portion.
The ring member includes a notch or an opening; and the high-pressure flow path and the second hole portion communicate with each other through the notch or the opening.
It should be noted that the present invention is not limited to the above-described embodiments. Within the scope of the present invention, any component of the above-described embodiments can be modified. In addition, any component can be added or omitted in the above-described embodiments.

[Reference Signs List]

1-1G: Expansion valve
2-2E: Valve main body
3: Valve element
4: Biasing device
5: Operation rod
6: Ring spring
8, 8A: Power element
20: Valve seat
21: First flow path
22: Second flow path
23, 23A, 23B, 23D, 23E, 23G: Return flow path
27: Valve through-hole
41: Coil spring
42: Valve element support
43: Spring receiving member
50, 50F: Double pipe
100: Refrigerant circulation system
101: Compressor
102: Condenser
104: Evaporator
VS: Valve chamber

Claims

An expansion valve capable of connecting to a double pipe in which a low-pressure refrigerant passes through an inner pipe and a high-pressure refrigerant passes between the inner pipe and an outer pipe disposed around the inner pipe, the expansion valve comprising:
a valve main body including a low-pressure flow path through which the low-pressure refrigerant flows and a high-pressure flow path through which the high-pressure refrigerant flows;

a power element attached to the valve main body; and

a heat transfer control portion that suppresses heat transfer between the power element and the high-pressure refrigerant flowing in the outer pipe by connecting the outer pipe to the valve main body eccentrically in a direction that separates from the power element further than the inner pipe.
The expansion valve according to claim 1, wherein the heat transfer control portion includes:
a first hole portion that is coaxial with the low-pressure flow path to which the inner pipe fits;

a second hole portion that is coaxial with the first hole portion and that fits with the outer pipe; and

a third hole portion that communicates with the high-pressure flow path and is eccentric to a side away from the power element with respect to the first hole portion and the second hole portion.
The expansion valve according to claim 2, wherein:
at least a portion of an outer circumferential surface of the inner pipe is in contact with an inner circumferential surface of the third hole portion.
The expansion valve according to claim 2 or 3, wherein:
the inner pipe includes a spiral portion having a spiral groove formed on an outer circumferential surface thereof, and the outer circumferential surface of the spiral portion other than the spiral groove is in contact with an inner circumferential surface of the outer pipe.
The expansion valve according to any of claims 2 to 4, wherein:
an end location of the first hole portion and an end location of the third hole portion on a power element side coincide with each other.
The expansion valve according to claim 1, wherein:
the heat transfer control portion includes:
a first hole portion that is coaxial with the low-pressure flow path to which the inner pipe fits, and

a second hole portion that fits with the outer pipe; and

the second hole portion is eccentric to a side away from the power element with respect to the first hole portion.
The expansion valve according to claim 6, wherein:
an end location of the first hole portion and an end location of the second hole portion on a power element side coincide with each other.