JP7403168B2 - 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.

The expansion valve is equipped with a drive mechanism for a valve member called a power element that includes a pressure working chamber. The valve body disposed inside the valve chamber and the power element are connected by an actuating rod, and the actuating rod is driven by changes in the pressure of the gas sealed in the pressure working chamber, opening or closing the valve body accordingly. It is designed to perform valve operation. The gas pressure in the pressure operating chamber changes depending on the balance between the heat transferred from the outside of the power element and the heat transferred to the refrigerant, so the valve body opens and closes autonomously, causing the refrigeration cycle to operate automatically. Control is achieved.

A typical expansion valve is connected to a high-pressure pipe through which refrigerant is delivered from a condenser of a refrigeration cycle and a low-pressure pipe through which refrigerant is delivered from an evaporator, respectively. On the other hand, the expansion valve disclosed in Patent Document 1 discloses a system in which double piping, in which the low pressure piping is the inner piping and the high pressure piping is the outer piping, is connected to the expansion valve. According to such a system, the routing of piping can be simplified.

JP2020-94793A

In the expansion valve disclosed in Patent Document 1, relatively high temperature refrigerant sent from the condenser flows between the outer pipe and the inner pipe, but the outer pipe is disposed near the power element. Ru. Therefore, in addition to the heat that the power element receives from the atmosphere, the heat emitted from the refrigerant flowing between the outer and inner pipes is also transferred to the power element, which increases the gas pressure in the pressure operating chamber and opens the valve. There is a risk that the timing may be advanced and the control of the refrigeration cycle may become inappropriate.

Therefore, an object of the present invention is to provide an expansion valve that can realize appropriate refrigeration cycle control while being able to connect double piping.

In order to achieve the above object, the expansion valve according to the present invention provides two types of expansion valves, in which a low-pressure refrigerant passes through an inner pipe, and a high-pressure refrigerant passes between an outer pipe arranged around the inner pipe and the inner pipe. An expansion valve to which heavy piping can be connected,
a valve body comprising a low-pressure passage through which the low-pressure refrigerant flows and a high-pressure passage through which the high-pressure refrigerant flows;
a power element attached to the valve body;
By connecting the outer piping to the valve body eccentrically in a direction farther from the power element than the inner piping, heat transfer between the power element and the high-pressure refrigerant flowing in the outer piping is suppressed. A transmission control section.

According to the present invention, it is possible to provide an expansion valve that can realize appropriate refrigeration cycle control while being able to connect double piping.

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 perspective view showing the valve body of this embodiment cut in half. FIG. 3 is a longitudinal sectional view of the expansion valve according to the second embodiment. FIG. 4 is a longitudinal sectional view of an expansion valve according to a third embodiment. FIG. 5 is a longitudinal sectional view of the expansion valve according to the fourth embodiment. FIG. 6 is a longitudinal sectional view of the expansion valve according to the fifth embodiment. FIG. 7 is a side view of the return flow path of this embodiment from the right side of FIG. 6. FIG. 8 is a longitudinal sectional view of the expansion valve according to the sixth embodiment. FIG. 9 is a side view of the return flow path of this embodiment viewed from the right side of FIG. 8. FIG. 10 is a longitudinal sectional view of the expansion valve according to the seventh embodiment. FIG. 11 is a longitudinal sectional view of the expansion valve according to the eighth embodiment. FIG. 12 is a perspective view of the valve body of this embodiment cut in half and shown together with a ring member.

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.

(First embodiment)
An overview of the expansion valve 1 in this embodiment will be described with reference to FIGS. 1 and 2. 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. FIG. 2 is a perspective view showing the valve body 2 of this embodiment cut in half.

In this embodiment, the expansion valve 1 is fluidly connected to a compressor 101, a condenser 102, and an 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.

In addition to the valve chamber VS, the valve body 2 includes a first flow path (also referred to as a high pressure flow path) 21, a second flow path 22, an intermediate chamber 221, and a return flow path 23. 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. A pipe (not shown) connected to the inlet side of the evaporator 104 is connected to the second flow path 22 .

The return flow path 23 extends through the valve body 2 orthogonally to the axis L. Let O be the axis of the return flow path 23. The return passage 23 includes an inlet passage 23a to which a pipe (not shown) connected to the outlet side of the evaporator 104 is connected, an intermediate passage (also referred to as a low-pressure passage) 23b, and a first passage having a larger diameter than the intermediate passage 23b. An enlarged diameter hole 23c, a second enlarged diameter hole 23d with a larger diameter than the first enlarged diameter hole 23c, and a third enlarged diameter hole 23e with a larger diameter than the second enlarged diameter hole 23d are coaxially arranged in series. . Although details will be described later, the intermediate passage 23b communicates with the lower space LS of the power element 8 via the vertical hole 2a.

In this embodiment, a plurality (here, three) of circumferential grooves 2c are formed over the entire circumference between the vertical hole 2a and the first enlarged diameter hole 23c on the inner circumference of the intermediate passage 23b. The bottom diameter of the circumferential groove 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 groove 2c do not interfere with each other. The circumferential groove 2c constitutes a heat transfer control section.

A double pipe 50 is connected to the return flow path 23 . The double pipe 50 includes an inner pipe 51 whose end fits into the intermediate passage 23b, and an outer pipe 52 which encloses the inner pipe 51 and whose end fits into the second enlarged diameter hole 23d. The inner pipe 51 has a flange portion 51a near the end, which 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 arranged between the end of the inner pipe 51 and the flange portion 51a, thereby sealing between the first enlarged diameter hole 23c and the outer periphery of the inner pipe 51. This prevents refrigerant leakage.

Further, the outer pipe 52 also has a flange portion 52a near the end thereof, which is formed by expanding a portion of the pipe and crushing it in the axial direction. The end of the outer pipe 52 does not bottom out at the step of the second enlarged diameter hole 23d, and the flange portion 52a is in contact with the side surface of the valve body 2. An O-ring OR2 held by the flange portion 52a is arranged between the end of the outer pipe 52 and the flange portion 52a, thereby sealing between the third enlarged diameter hole 23e and the outer periphery of the outer pipe 52. This prevents refrigerant leakage.

The 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 within a plane including the axis L and the axis O, and is inclined with respect to the axis L and the axis O, and its upper end is open at the inner periphery of the second enlarged diameter hole 23d. However, its lower end is open at the inner periphery 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. Further, 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 fits into a fitting hole at the lower end of the stopper member 84 .

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.

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 onto the valve body 2, and has the function of sealing the valve chamber VS and the function of adjusting the biasing force of the coil spring 41. .

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.

The opening at the top of the substantially conical upper lid member 82 can be sealed with a stopper 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-molding a metal plate, for example, and is formed by connecting a flange portion and a 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 assembling the power element 8, while placing the stopper member 84 between the diaphragm 83 and the receiving member 86, the outer peripheral parts of the upper cover member 82, the diaphragm 83, and the receiving member 86 are overlapped, and the outer peripheral parts are, for example, They are integrated by circumferential welding using TIG welding, laser welding, plasma welding, etc.

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

When assembling the power element 8 assembled as described above to the valve body 2, the male thread 86a on the outer periphery of the lower end of the hollow cylindrical portion of the receiving member 86 is inserted into the vertical hole 2a communicating with the return passage 23 of the valve body 2. It is screwed into the female thread 2b formed around the periphery. When the male thread of the receiving member 86 is screwed into the female thread 2b, the lower surface of the flange of 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 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 via 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. 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 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 enters the return flow path 23 of the expansion valve 1, further passes through the inner pipe 51 of the double pipe 50, and is returned to the compressor 101 side. 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.

Low-pressure refrigerant is delivered from the expansion valve 1 to the compressor 101, and high-pressure refrigerant is delivered 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 through the first flow path 21 and between the outer pipe 52 and the inner pipe 51 of the double pipe 50.

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 passage 23 via the vertical hole 2a. 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.

As described above, the high-pressure refrigerant having a temperature higher than the atmospheric temperature is delivered to the second enlarged diameter hole 23d via 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 through the inside of the valve body 2 to the power element 8, the working gas in the pressure working chamber PO is affected, and the power element 8, a different pressure may be created in the pressure working chamber PO than if only heat from the atmosphere was transferred.

On the other hand, according to the present embodiment, since the circumferential groove 2c is formed on the inner periphery of the intermediate passage 23b between the vertical hole 2a and the second enlarged diameter hole 23d, the relative temperature that enters the intermediate passage 23b is The refrigerant having a low temperature enters the circumferential groove 2c. Thereby, 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 expanding the heat exchange area in the intermediate path 23b by providing the circumferential groove 2c, the influence of the heat of the high-pressure refrigerant passing through the second enlarged diameter hole 23d is suppressed, and the appropriate control operation of the power element 8 is achieved. realizable.

(Second embodiment)
FIG. 3 is a longitudinal cross-sectional view of an expansion valve 1A according to the second embodiment. This embodiment differs from the first embodiment only in the shape of the valve body 2A. 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.

The valve body 2A of this embodiment has an annular wall 2Ac that protrudes radially inward in the intermediate passage 23b instead of providing a circumferential groove. The annular wall 2Ac can be formed integrally with the valve body 2A by adjusting the cutting amount of the tool when cutting the return passage 23A from both sides, leaving a part of the valve body 2A. However, the annular wall 2Ac having an outer diameter equal to the inner diameter of the intermediate passage 23b may be formed as a separate member, and may be further fitted and fixed to the intermediate passage 23b by press-fitting or the like. The annular wall 2Ac constitutes a heat transfer control section.

According to this embodiment, a part of the refrigerant that has entered 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, the refrigerant passes through the surface of the annular wall 2Ac. can promote heat transfer to. 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, by providing the annular wall 2Ac, the heat exchange area in the intermediate path 23b is expanded, and by changing the flow of the refrigerant, the amount of heat transferred from the second enlarged diameter hole 23d to the power element 8 can be reduced. Therefore, the influence of the heat of the high-pressure refrigerant passing through the second enlarged diameter hole 23d can be suppressed, and an appropriate control operation of the power element 8 can be realized.

(Third embodiment)
FIG. 4 is a longitudinal cross-sectional view of an expansion valve 1B according to the third embodiment. This embodiment differs from the first embodiment only in the shape of the valve body 2B. 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.

The valve body 2B of this embodiment has a blind hole 2Bc inclined with respect to the axis O in the intermediate passage 23b instead of providing a circumferential groove. The axis of the blind hole 2Bc does not intersect with the inner periphery of the return passage 23B and passes outside the inlet passage 23a in the axial direction. 2Bc can be formed by cutting. However, the blind hole 2Bc may be formed by drilling from the upper surface of the valve body 2B to the intermediate passage 23b and further sealing the exposed outer end of the hole with a plug or the like. The blind hole 2Bc constitutes a heat transfer control section.

According to this embodiment, the blind hole 2Bc extends between the vertical hole 2a and the second enlarged diameter hole 23d from the inner periphery of the intermediate passage 23b toward the outside in the radial direction of the second enlarged diameter hole 23d. It is formed like this. Therefore, a part of the refrigerant flowing from the left to the right in the return flow path 23B easily enters the blind hole 2Bc, thereby reducing the transfer of heat from the inner peripheral wall surface of the blind hole 2Bc to the refrigerant. promoted. That is, by expanding the heat exchange area in the intermediate path 23b by arranging the blind hole 2Bc, the amount of heat transferred from the second enlarged diameter hole 23d to the power element 8 can be reduced. By suppressing the influence of the heat of the high-pressure refrigerant passing through, it is possible to realize an appropriate control operation of the power element 8.

(Fourth embodiment)
FIG. 5 is a longitudinal cross-sectional view of an expansion valve 1C according to the fourth embodiment. This embodiment differs from the first embodiment only in the shape of the valve body 2C. 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.

In the valve main body 2C of this embodiment, no circumferential groove is provided in the intermediate passage 23b. Instead, an annular groove 2Cc is formed in the upper end surface of the valve body 2B around the vertical hole 2a. A part of the annular groove 2Cc is located on the radially outer side of the first enlarged diameter hole 23c. The annular groove 2Cc constitutes a heat transfer control section.

According to this embodiment, since the annular groove 2Cc is formed on the radially outer side of the first enlarged diameter hole 23c between the vertical hole 2a and the second enlarged diameter hole 23d, the annular groove 2Cc is formed inside the second enlarged diameter hole 23d. The heat transfer path from the entered refrigerant to the power element 8 becomes narrower, thereby reducing the amount of heat transferred to the power element 8. Therefore, the influence of the heat of the high-pressure refrigerant passing through the second enlarged diameter hole 23d can be suppressed, and an appropriate control operation of the power element 8 can be realized.

(Fifth embodiment)
FIG. 6 is a longitudinal cross-sectional view of an expansion valve 1D according to the fifth embodiment. FIG. 7 is a side view of the return flow path 23D of this embodiment viewed from the right side of FIG. 6. This embodiment differs from the first embodiment only in the shape of the return passage 23D of the valve body 2D. 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.

In the valve body 2D of this embodiment, the second enlarged diameter hole 23Dd is connected to the eccentric hole (here, the third hole) 23D1 on the first enlarged diameter hole (here, the first hole) 23c side, and the third enlarged diameter hole 23D1. It is divided into a coaxial hole (here, a second hole portion) 23D2 on the diameter hole 23e side. As shown in FIG. 6, the eccentric hole 23D1, which has a larger diameter than the first enlarged diameter hole 23c, is eccentric downward with respect to the first enlarged diameter hole 23c, but the coaxial hole 23D2, which has a larger diameter than the eccentric hole 23D1, has a larger diameter than the first enlarged diameter hole 23c. It is coaxial with the first enlarged diameter hole 23c. When 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 upper end position of the first enlarged diameter hole 23c and the upper end position of the eccentric hole 23D1 match, and it is preferable that the lower end position of the eccentric hole 23D1 and the lower end position of the coaxial hole 23D2 match. The end of the inner pipe 51 fits into the intermediate path 23b, and the end of the outer pipe 52 fits into the coaxial hole 23D2. The eccentric hole 23D1 constitutes a heat transfer control section.

The refrigerant supplied between the outer pipe 52 and the inner pipe 51 heads to the first flow path 21 after passing through the eccentric hole 23D1. According to this embodiment, since the eccentric hole 23D1 is shifted in the direction away from the power element 8, the amount of heat transferred to the power element 8 from the refrigerant that has entered the eccentric hole 23D1 can be reduced. Thereby, the influence of the heat of the high-pressure refrigerant can be suppressed, and an appropriate control operation of the power element 8 can be realized.
stomach.

(Sixth embodiment)
FIG. 8 is a longitudinal sectional view of an expansion valve 1E according to the sixth embodiment. FIG. 9 is a side view of the return flow path 23E of this embodiment viewed from the right side of FIG. This embodiment differs from the first embodiment only in the shape of the return passage 23E of the valve body 2E. 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.

In the valve body 2E of this embodiment, the second enlarged diameter hole (here, the second hole portion) 23Ed and the third enlarged diameter hole 23Ee are relative to the first enlarged diameter hole (here, the first hole portion) 23c. Eccentric downwards. When 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 position of the upper end of the first enlarged diameter hole 23c and the position of the upper end of the second enlarged diameter hole 23Ed match. The end of the inner pipe 51 fits into the intermediate passage 23b, and the end of the outer pipe 52 fits into the second enlarged diameter hole 23Ed. Therefore, the outer pipe 52 of the double pipe 50 is also eccentrically downward with respect to the inner pipe 51. The second enlarged diameter hole 23Ed constitutes a heat transfer control section.

The refrigerant supplied between the outer pipe 52 and the inner pipe 51 heads to the first flow path 21 after passing through the second enlarged diameter hole 23Ed. According to this embodiment, since the second enlarged diameter hole 23Ed is shifted in a direction further away from the power element 8, the heat transferred from the refrigerant that has entered the second enlarged diameter hole 23Ed to the power element 8 is reduced. The amount can be reduced. Thereby, the influence of the heat of the high-pressure refrigerant can be suppressed, and an appropriate control operation of the power element 8 can be realized.

(Seventh embodiment)
FIG. 10 is a longitudinal sectional view of the expansion valve 1F according to the seventh embodiment. This embodiment combines the valve body 2D of the fifth embodiment with a double pipe 50F that is different from the above embodiment. 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.

The double pipe 50F has an inner pipe 51F and an outer pipe 52F. The outer pipe 52F has the same configuration as the embodiment described above. On the other hand, the inner pipe 51F is formed by connecting a circular pipe portion 51Fb and a spiral portion 51Fc. A spiral groove 51Fd is formed on the outer periphery of the spiral portion 51Fc, and the outer peripheral surface other than the spiral groove 51Fd is a cylindrical surface. The double pipe 50F constitutes a heat transfer control section.

When the inner pipe 51F is inserted into the outer pipe 52F, the outer peripheral surface of the spiral portion 51Fc contacts the inner peripheral surface of the outer pipe 52F, thereby forming a spiral passage along the spiral groove 51Fd. High pressure refrigerant will flow along this path.

When attaching the double piping 50F to the return passage 23D of the valve body 2D, the end of the outer piping 52F fits into the coaxial hole 23D2, and the end of the inner piping 51F protruding from the outer piping 52F connects to the intermediate passage 23b. to fit. The axis of the spiral portion 51Fc coincides with the axis O1 of the return flow path 23D, but the axis of the circular tube portion 51Fb is eccentric upward, so that when assembled to the valve body 2D, the axis of the circular tube portion 51Fb is The upper part contacts 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 heads toward 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, but by arranging the spiral groove 51Fd, the heat transfer area increases. 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 peripheral surface of the circular tube portion 51b of the inner pipe 51F is in contact with the eccentric hole 23D1, the upper circumference of the eccentric hole 23D1 is cooled by the refrigerant passing through the inner pipe 51F. Due to the above synergistic effect, the influence of the heat of the high-pressure refrigerant passing through the second enlarged diameter hole 23Fd can be suppressed, and an appropriate control operation of the power element 8 can be realized.

(Eighth embodiment)
FIG. 11 is a longitudinal sectional view of an expansion valve 1G according to the eighth embodiment. FIG. 12 is a perspective view of the valve body 2G of this embodiment cut in half and shown together with the ring member 60. This embodiment differs from the first embodiment only in that a circumferential groove is not formed in the return passage 23G of the valve body 2G, and a ring member 60 is provided. 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.

In this embodiment, a ring member 60 made of resin is disposed so as to fit into the inner periphery of the second enlarged diameter hole (second hole portion in this case) 23d. A notch 60a is formed in a part of the ring member 60 in the circumferential direction. The ring member 60 is arranged in the second enlarged diameter hole 23d such that the notch 60a is aligned with the first flow path (high pressure flow path) 21. As a result, the entire entrance of the first flow path 21 is opened, and the radially inner side of the ring member 60 and the first flow path 21 can be communicated via the notch 60a. Instead of the notch 60a, an opening communicating between the inner and outer peripheries of the ring member 60 may be provided.

The inner circumferential surface of the ring member 60 contacts the outer circumferential surface of the flange portion 51a of the inner pipe 51, and the left end of the ring member 60 contacts the stepped portion between the first enlarged diameter hole 23c and the second enlarged diameter hole 23d. The right end of the ring member 60 is in contact with the end 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 section.

The refrigerant supplied between the outer pipe 52 and the inner pipe 51 enters the second enlarged diameter hole 23d and then passes through the notch 60a toward the first flow path 21. According to this embodiment, since the ring member 60 having heat insulation properties is disposed between the refrigerant that has entered the second enlarged diameter hole 23d and the second enlarged diameter hole 23d, the second enlarged diameter hole 23d The amount of heat transferred to the power element 8 from the refrigerant that has entered the hole 23Ed can be reduced. Thereby, the influence of the heat of the high-pressure refrigerant can be suppressed, and an appropriate control operation of the power element 8 can be realized. Ring member 60 can be used in combination with the embodiments described above.

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.

1 to 1G: Expansion valve 2 to 2E: Valve body 3: Valve body 4: Biasing device 5: Operating rod 6: Ring spring 8: Power element 20: Valve seat 21: First flow path 22: Second flow path 23 , 23A, 23B, 23D, 23E, 23G: Return passage 27: Valve hole 41: Coil spring 42: Valve body support 43: Spring receiving member 50, 50F: Double piping 60: Ring member 100: Refrigerant circulation system 101 : Compressor 102 : Capacitor 104 : Evaporator VS : Valve chamber

Claims (3)

An expansion valve capable of connecting a double pipe in which a low-pressure refrigerant passes through an inner pipe, and a high-pressure refrigerant passes between an outer pipe arranged around the inner pipe and the inner pipe,
a valve body comprising a low-pressure passage through which the low-pressure refrigerant flows and a high-pressure passage through which the high-pressure refrigerant flows;
a power element attached to the valve body;
By connecting the outer piping to the valve body eccentrically in a direction farther from the power element than the inner piping, heat transfer between the power element and the high-pressure refrigerant flowing in the outer piping is suppressed. A transmission control unit;
An expansion valve characterized by: The heat transfer control unit has a first hole coaxial with the low-pressure flow path into which the inner pipe fits, and a second hole into which the outer pipe fits, and the second hole includes: eccentric with respect to the first hole on a side away from the power element;
The expansion valve according to claim 1 , characterized in that: an end position of the first hole and an end position of the second hole on the power element side match;
The expansion valve according to claim 2 , characterized in that:

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