Expansion valve

Abstract

An expansion valve is provided that can connect to a double-layer piping system and control an appropriate refrigeration cycle. The expansion valve, capable of connecting to a double-layer piping system in which low-pressure refrigerant flows through an inner piping system and high-pressure refrigerant flows through an outer piping system surrounding the inner piping system, comprises: a valve body having a low-pressure flow path for the low-pressure refrigerant and a high-pressure flow path for the high-pressure refrigerant; a power element mounted on the valve body; and a heat transfer control unit that, by connecting the outer piping system to the valve body in an eccentric manner relative to the inner piping system away from the power element, suppresses heat transfer between the power element and the high-pressure refrigerant flowing in the outer piping system.

Description

Technical Field

[0001] This invention relates to an expansion valve. Background Technology

[0002] Previously, in refrigeration cycle systems used in automobiles, such as air conditioning units, temperature-sensitive expansion valves were used to adjust the amount of refrigerant passing through based on temperature.

[0003] In an expansion valve, a drive mechanism for the valve components is provided; this drive mechanism is referred to as the power element containing the pressure chamber. The valve core, housed within the valve chamber, is connected to the power element by an actuating rod. The actuating rod is driven by pressure changes in the gas sealed within the pressure chamber, correspondingly opening or closing the valve core. Because the gas pressure within the pressure chamber changes according to the balance between heat transferred from the outside of the power element and heat transferred to the refrigerant, the valve core opens and closes autonomously, achieving automatic control of the refrigeration cycle.

[0004] The high-pressure piping supplying refrigerant from the condenser of the refrigeration cycle and the low-pressure piping supplying refrigerant from the evaporator are each connected to a conventional expansion valve. In contrast, Patent Document 1 discloses a system in which a double-layer piping system is connected to the expansion valve, with the low-pressure piping as the inner layer and the high-pressure piping as the outer layer. This system simplifies piping management.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2020-94793

[0008] The technical problem that the invention aims to solve

[0009] In the expansion valve disclosed in Patent Document 1, a relatively hot refrigerant from the condenser flows between an outer pipe and an inner pipe, but the outer pipe is located near the power element. Therefore, in addition to the heat received by the power element from the atmosphere, the heat emitted by the refrigerant flowing between the outer and inner pipes is also transferred to the power element. As a result, the pressure in the pressure chamber may increase, the valve opening time may be advanced, etc., making the control of the refrigeration cycle inappropriate. Summary of the Invention

[0010] Therefore, the object of the present invention is to provide an expansion valve that can connect double-layer piping and achieve appropriate control of the refrigeration cycle.

[0011] Technical means for solving technical problems

[0012] To achieve the above objectives, the expansion valve of the present invention is capable of connecting a double-layer piping system, wherein a low-pressure refrigerant passes through the inner piping, and a high-pressure refrigerant passes between the outer piping system disposed around the inner piping and the inner piping. The expansion valve has:

[0013] The valve body has a low-pressure flow path for the low-pressure refrigerant to flow and a high-pressure flow path for the high-pressure refrigerant to flow;

[0014] A power element, which is mounted on the valve body; and

[0015] A heat transfer control unit that connects the outer piping to the valve body in an eccentric manner relative to the inner piping in the direction away from the power element, thereby suppressing heat transfer between the power element and the high-pressure refrigerant flowing in the outer piping.

[0016] Invention Effects

[0017] According to the present invention, an expansion valve is provided that can connect double-layer piping and achieve appropriate control of the refrigeration cycle. Attached Figure Description

[0018] Figure 1 This is a schematic cross-sectional view illustrating an example of applying the expansion valve of this embodiment to a refrigerant circulation system.

[0019] Figure 2 This is a perspective view showing the valve body of this embodiment divided into two parts.

[0020] Figure 3 This is a longitudinal sectional view of the expansion valve according to the second embodiment.

[0021] Figure 4 This is a longitudinal sectional view of the expansion valve according to the third embodiment.

[0022] Figure 5 This is a longitudinal sectional view of the expansion valve according to the fourth embodiment.

[0023] Figure 6 This is a longitudinal sectional view of the expansion valve according to the fifth embodiment.

[0024] Figure 7 From Figure 6 A diagram showing the return flow path of this embodiment from the right side view.

[0025] Figure 8 This is a longitudinal sectional view of the expansion valve according to the sixth embodiment.

[0026] Figure 9 From Figure 8A diagram showing the return flow path of this embodiment from the right side view.

[0027] Figure 10 This is a longitudinal sectional view of the expansion valve according to the seventh embodiment.

[0028] Figure 11 This is a longitudinal sectional view of the expansion valve according to the eighth embodiment.

[0029] Figure 12 This is a perspective view showing the valve body of this embodiment divided into two parts and together with the annular component.

[0030] Symbol Explanation

[0031] 1~1G: Expansion valve

[0032] 2~2E: Valve body

[0033] 3: Valve core

[0034] 4: Force application device

[0035] 5: Action Stick

[0036] 6: Ring spring

[0037] 8: Power components

[0038] 20: Valve seat

[0039] 21: First flow path

[0040] 22: Second Flow Path

[0041] 23, 23A, 23B, 23D, 23E, 23G: Return Flow Path

[0042] 27: Valve through hole

[0043] 41: Coil spring

[0044] 42: Valve core support component

[0045] 43: Spring bracket component

[0046] 50, 50F: Double-layer piping

[0047] 60: Ring-shaped component

[0048] 100: Refrigerant Circulation System

[0049] 101: Compressor

[0050] 102: Condenser

[0051] 104: Evaporator

[0052] VS: Valve chamber Detailed Implementation

[0053] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0054] (Definition of direction)

[0055] In this specification, the direction from valve core 3 toward actuating rod 5 is defined as the "upward direction," and the direction from actuating rod 5 toward valve core 3 is defined as the "downward direction." Therefore, in this specification, regardless of the orientation of expansion valve 1, the direction from valve core 3 toward actuating rod 5 will be referred to as the "upward direction."

[0056] Furthermore, in this specification, "coaxial" refers not only to a relationship in which two or more axes are completely aligned, but also to a relationship that is not strictly aligned but approximately aligned. "Eccentric" refers to a relationship in which the center or axis of one axis is offset (misaligned) relative to the center or axis of another axis in a certain direction. Regarding the parallelism of axes, the terms "coaxial" and "eccentric" indicating the relationship between axes are not limited to a strictly aligned relationship.

[0057] (First Implementation)

[0058] Reference Figure 1 , 2 An overview of the expansion valve 1 in this embodiment will be provided. Figure 1 This is a schematic cross-sectional view illustrating an example of applying the expansion valve 1 of this embodiment to the refrigerant circulation system 100. Figure 2 This is a perspective view showing the valve body 2 of this embodiment divided into two parts.

[0059] In this embodiment, the expansion valve 1 is fluidly connected to the compressor 101, the condenser 102, and the evaporator 104. The axis of the expansion valve 1 is defined as L.

[0060] exist Figure 1 In the expansion valve 1, there are: valve body 2 with valve chamber VS, valve core 3, force application device 4, actuating rod 5 and power element 8.

[0061] In addition to the valve chamber VS, the valve body 2 also includes a first flow path 21 (also called a high-pressure flow path), 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, through which refrigerant (also called fluid) is supplied to the valve chamber VS. The second flow path 22 is a discharge-side flow path (also called an outlet-side flow path), through which the fluid in the valve chamber VS is discharged to the outside of the expansion valve via the valve through-hole 27, the intermediate chamber 221, and the discharge-side flow path. A piping (not shown) is connected to the inlet side of the evaporator 104 via the second flow path 22.

[0062] The return flow path 23 is orthogonal to the axis L and extends through the valve body 2. The axis of the return flow path 23 is set to O. The return flow path 23 continuously and coaxially connects the inlet path 23a (not shown) to the piping (not shown) for connection to the outlet side of the evaporator 104, the intermediate path (also called the low-pressure flow path) 23b, a first enlarged diameter orifice 23c (larger than the intermediate path 23b), a second enlarged diameter orifice 23d (larger than the first enlarged diameter orifice 23c), and a third enlarged diameter orifice 23e (larger than the second enlarged diameter orifice 23d). Details are described later, but the intermediate path 23b is connected to the lower space LS of the power element 8 via the longitudinal hole 2a.

[0063] In this embodiment, multiple (here, three) peripheral grooves 2c are formed around the entire circumference of the intermediate path 23b between the longitudinal hole 2a and the first enlarged diameter hole 23c. The bottom diameter of the peripheral grooves 2c is preferably smaller than the inner diameter of the second enlarged diameter hole 23d. It is desirable that the inner piping 51 does not interfere with the peripheral grooves 2c. The peripheral grooves 2c constitute a heat transfer control section.

[0064] The double-layer piping 50 is connected to the return flow path 23. The double-layer piping 50 has an inner piping 51 whose end is fitted into the intermediate path 23b and an outer piping 52 that encloses the inner piping 51 and whose end is fitted into the second enlarged diameter hole 23d. The inner piping 51 has a flange portion 51a near its end, formed by expanding a portion of the pipe's diameter and crushing the pipe along its axial direction. An O-ring OR1 held by the flange portion 51a is disposed between the end of the inner piping 51 and the flange portion 51a, thereby sealing the first enlarged diameter hole 23c and the outer periphery of the inner piping 51 to prevent refrigerant leakage.

[0065] Additionally, the outer pipe 52 also has a flange 52a near its end, formed by expanding a portion of the pipe's diameter and crushing the pipe along its axial direction. The end of the outer pipe 52 has no bottom at the stepped portion of the second enlarged bore 23d, and the flange 52a abuts against the side of the valve body 2. An O-ring OR2, held by the flange 52a, is disposed between the end of the outer pipe 52 and the outer pipe 52a, thereby sealing the third enlarged bore 23e and the outer periphery of the outer pipe 52 to prevent refrigerant leakage.

[0066] 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.

[0067] The first flow path 21 has an axis in a plane including axes L and O, and is inclined relative to axes L and O. The upper end of the first flow path 21 opens within the inner circumference of the second enlarged diameter hole 23d, and the lower end of the first flow path 21 opens below the valve seat 20 and within the inner circumference of the valve chamber VS. That is, the interior of the second enlarged diameter hole 23d communicates with the valve chamber VS via the first flow path 21. In addition, the valve chamber VS communicates with the intermediate chamber 221 via the valve seat 20 and the valve through hole 27.

[0068] The actuation rod insertion hole 28 formed above the intermediate chamber 221 functions to guide the actuation rod 5, and the annular recess 29 formed above the actuation rod insertion hole 28 functions to accommodate the annular spring 6. The annular spring 6 causes multiple spring plates to abut against the outer periphery of the actuation rod 5 and apply a specified force.

[0069] Valve core 3 is disposed within valve chamber VS. When valve core 3 is seated on valve seat 20 of valve body 2, the flow of refrigerant through valve orifice 27 is restricted. This state is referred to as the non-connected state. However, even when valve core 3 is seated on valve seat 20, there is a restricted amount of refrigerant flow. On the other hand, when valve core 3 leaves valve seat 20, the flow of refrigerant through valve orifice 27 increases. This state is referred to as the connected state.

[0070] The actuating rod 5 is inserted into the valve through hole 27 with a specified gap. The lower end of the actuating rod 5 contacts the upper surface of the valve core 3. The upper end of the actuating rod 5 is fitted into the fitting hole at the lower end of the stop member 84.

[0071] The actuating rod 5 can overcome the force generated by the force-applying device 4 and push the valve core 3 in the opening direction. When the actuating rod 5 moves downward, the valve core 3 leaves the valve seat 20, and the expansion valve 1 becomes open.

[0072] The force application device 4 includes a helical spring 41 formed by winding a circular cross-section wire into a spiral shape, a valve core support 42, and a spring bracket component 43.

[0073] The valve core support 42 is installed on the upper end of the helical spring 41. The upper surface of the valve core support 42 is used for welding the spherical valve core 3, and the two become one piece.

[0074] The spring bracket component 43 supporting the lower end of the helical spring 41 can be screwed relative to the valve body 2. The spring bracket component 43 has the function of sealing the valve chamber VS and adjusting the force of the helical spring 41.

[0075] The power element 8 has a bolt 81, a cover component 82, a diaphragm 83, a bearing component 86, and a stop component 84.

[0076] The opening at the top of the roughly conical top cover component 82 can be sealed by a bolt 81.

[0077] The diaphragm 83 is made of a sheet of thin metal (e.g., SUS) with a concave-convex shape forming multiple concentric circles, and the diaphragm 83 has an outer diameter that is approximately the same as the outer diameter of the cover member 82 and the support member 86.

[0078] The supporting component 86 is formed, for example, by stamping a sheet of metal and connecting a flange portion and a hollow cylindrical portion.

[0079] A stop member 84 is disposed between the upper cover member 82 and the bearing member 86, and the upper surface of the stop member 84 is in contact with the center of the lower surface of the diaphragm 83.

[0080] When assembling the power component 8, while placing the stop member 84 between the diaphragm 83 and the bearing member 86, the outer peripheries of the cover member 82, the diaphragm 83, and the bearing member 86 are overlapped, and these outer peripheries are integrated by peripheral welding, such as TIG welding, laser welding, or plasma welding.

[0081] Next, working gas is sealed into the space (referred to as the pressure chamber PO) surrounded by the upper cover component 82 and the diaphragm 83 through the opening formed in the upper cover component 82. Then, the opening is sealed by a bolt 81, and further, the bolt 81 is fixed to the upper cover component 82 by means of projection welding or the like.

[0082] When assembling the modular power element 8 as described above into the valve body 2, the external thread 86a of the lower outer periphery of the hollow cylindrical portion of the bearing member 86 engages with the internal thread 2b formed on the inner periphery of the longitudinal hole 2a communicating with the return flow path 23 of the valve body 2. When the external thread of the bearing member 86 is screwed into the internal thread 2b, the lower surface of the flange portion of the bearing member 86 abuts against the upper end face of the valve body 2. This allows the power element 8 to be fixed to the valve body 2.

[0083] At this time, a gasket PK is installed between the power element 8 and the valve body 2 to prevent refrigerant leakage when the power element 8 is installed onto the valve body 2. In this state, the lower space LS of the power element 8 is connected to the return flow path 23 via the longitudinal hole 2a.

[0084] (Action of the expansion valve)

[0085] Reference Figure 1The operation of expansion valve 1 will be explained using an example. High-pressure refrigerant, pressurized by compressor 101, is liquefied by condenser 102 and delivered to expansion valve 1. Furthermore, the refrigerant, after adiabatic expansion using expansion valve 1, is sent to evaporator 104, where it exchanges heat with the air flowing around it. Refrigerant returning from evaporator 104 enters the return flow path 23 of expansion valve 1, and then returns to compressor 101 via the inner pipe 51 of double-layer piping 50. At this time, the refrigerant passes through evaporator 104, thereby lowering the fluid pressure in return flow path 23 compared to the fluid pressure in second flow path 22. The refrigerant after passing through evaporator 104 is referred to as low-pressure refrigerant.

[0086] Low-pressure refrigerant is delivered from expansion valve 1 to compressor 101, and high-pressure refrigerant is delivered from condenser 102 to expansion valve 1. More specifically, high-pressure refrigerant from condenser 102 is supplied to valve chamber VS via the outer piping 52 and inner piping 51 of double piping 50 and the first flow path 21.

[0087] When the valve core 3 is seated on the valve seat 20 (in the non-connected state), the flow rate of refrigerant from the valve chamber VS through the valve through-hole 27, intermediate chamber 221, and second flow path 22 to the evaporator 104 is restricted. On the other hand, when the valve core 3 leaves the valve seat 20 (in the connected state), the flow rate of refrigerant from the valve chamber VS through the valve through-hole 27, intermediate chamber 221, and second flow path 22 to the evaporator 104 increases. The switching between the closed and open states of the expansion valve 1 is performed by the actuating rod 5 connected to the power element 8 via the stop member 84.

[0088] exist Figure 1 Within the power element 8, a pressure chamber PO and a lower space LS are separated by a diaphragm 83. Therefore, when the working gas in the pressure chamber PO is liquefied, the diaphragm 83 and the stop member 84 rise, causing the actuating rod 5 to move upward under the force of the coil spring 41. Conversely, when the liquefied working gas is vaporized, the diaphragm 83 and the stop member 84 are pushed downward, causing the actuating rod 5 to move downward. This switches the expansion valve 1 between its open and closed states.

[0089] Furthermore, the lower space LS of the power element 8 is connected to the return flow path 23 via the longitudinal hole 2a. Therefore, the volume of the working gas within the pressure chamber PO varies according to the temperature and pressure of the refrigerant flowing in the return flow path 23, thus driving the actuating rod 5. In other words, in Figure 1 In the expansion valve 1 described herein, the amount of refrigerant supplied from the expansion valve 1 to 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.

[0090] As described above, high-pressure refrigerant with a temperature higher than atmospheric temperature is delivered to the second expansion orifice 23d through the outer pipe 52 and inner pipe 51 of the double-layer piping 50. At this time, if the heat of the high-pressure refrigerant is transferred from the inner wall of the second expansion orifice 23d along the interior of the valve body 2 to the power element 8, the working gas in the pressure chamber PO will be affected, and a pressure different from the pressure generated in the pressure chamber PO when only heat from the atmosphere is transferred to the atmosphere of the power element 8 may be generated.

[0091] In this embodiment, a peripheral groove 2c is formed on the inner periphery of the intermediate path 23b between the longitudinal hole 2a and the second enlarged diameter hole 23d. The refrigerant, which has a relatively low temperature, enters the peripheral groove 2c after entering the intermediate path 23b. This promotes heat transfer from the bottom and side walls of the peripheral groove 2c to the refrigerant, thereby reducing the amount of heat transferred from the second enlarged diameter hole 23d to the power element 8. In other words, by increasing the heat exchange area in the intermediate path 23b through the arrangement of the peripheral groove 2c, the influence of heat generated by the high-pressure refrigerant passing through the second enlarged diameter hole 23d can be suppressed, enabling proper control of the power element 8.

[0092] The expansion valve of the present invention is capable of connecting a double-layer piping system, wherein a low-pressure refrigerant passes through the inner piping and a high-pressure refrigerant passes between the outer piping system disposed around the inner piping and the inner piping system. The expansion valve has:

[0093] The valve body has a low-pressure flow path for the low-pressure refrigerant to flow and a high-pressure flow path for the high-pressure refrigerant to flow;

[0094] A power element, which is mounted on the valve body; and

[0095] A heat transfer control unit that facilitates heat transfer between the power element and the low-pressure refrigerant flowing in the low-pressure flow path, or inhibits heat transfer between the power element and the high-pressure refrigerant flowing in the outer piping.

[0096] The heat transfer control unit is a slot disposed in the low-pressure flow path.

[0097] (Second Implementation)

[0098] Figure 3 This is a longitudinal sectional view of the expansion valve 1A according to the second embodiment. Compared to the first embodiment, this embodiment differs only in the shape of the valve body 2A. All other structures are the same as in the embodiments described above, therefore the same symbols are used and repeated descriptions are omitted.

[0099] In this embodiment, the valve body 2A has an annular wall 2Ac protruding radially inward within the intermediate passage 23b instead of a circumferential groove. By adjusting the tool feed rate during machining of the return flow path 23A from both sides, a portion of the valve body 2A is left untouched, thereby allowing the annular wall 2Ac to be integrally formed with the valve body 2A. However, it is also possible to form the annular wall 2Ac with an outer diameter equal to the inner diameter of the intermediate passage 23b using different components, and then fit and fix the annular wall 2Ac to the intermediate passage 23b by pressing or the like. The annular wall 2Ac constitutes a heat transfer control section.

[0100] According to this embodiment, a portion of the refrigerant entering the return flow path 23A flows into the inner piping 51 through the inner side of the annular wall 2Ac, which promotes heat transfer to the refrigerant via the surface of the annular wall 2Ac. On the other hand, the remaining refrigerant contacts the annular wall 2Ac and returns, entering the longitudinal hole 2a and promoting heat transfer from the stop member 84. That is, by providing the annular wall 2Ac to expand the heat exchange area in the intermediate path 23b and 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 generated by the high-pressure refrigerant passing through the second enlarged diameter hole 23d can be suppressed, and appropriate control operation of the power element 8 can be achieved.

[0101] The expansion valve of the present invention is capable of connecting a double-layer piping system, wherein a low-pressure refrigerant passes through the inner piping and a high-pressure refrigerant passes between the outer piping system disposed around the inner piping and the inner piping system. The expansion valve has:

[0102] The valve body has a low-pressure flow path for the low-pressure refrigerant to flow and a high-pressure flow path for the high-pressure refrigerant to flow;

[0103] A power element, which is mounted on the valve body; and

[0104] A heat transfer control unit that facilitates heat transfer between the power element and the low-pressure refrigerant flowing in the low-pressure flow path, or inhibits heat transfer between the power element and the high-pressure refrigerant flowing in the outer piping.

[0105] The heat transfer control unit is disposed on the wall of the low-pressure flow path.

[0106] (Third implementation method)

[0107] Figure 4 This is a longitudinal sectional view of the expansion valve 1B according to the third embodiment. Compared to the first embodiment, this embodiment differs only in the shape of the valve body 2B. All other structures are the same as in the embodiments described above; therefore, the same symbols are used and repeated descriptions are omitted.

[0108] In this embodiment, the valve body 2B has a pocket hole 2Bc inclined relative to the axis O within the intermediate passage 23b instead of a peripheral groove. Since the axis of the pocket hole 2Bc does not intersect the inner circumference of the return flow passage 23B but passes outside the axial direction of the inlet passage 23a, the pocket hole 2Bc can be formed by cutting with a tool such as a drill bit inserted obliquely into the return flow passage 23B. However, the pocket hole 2Bc can also be formed by perforating the upper surface of the valve body 2B down to the intermediate passage 23b and then sealing the exposed end of the hole with a plug or the like. The pocket hole 2Bc constitutes a heat transfer control section.

[0109] According to this embodiment, the bag hole 2Bc is formed between the longitudinal hole 2a and the second enlarged diameter hole 23d, extending radially outward from the inner periphery of the intermediate path 23b toward the second enlarged diameter hole 23d. Therefore, a portion of the refrigerant flowing from left to right in the return flow path 23B easily enters the bag hole 2Bc, thereby promoting heat transfer from the inner peripheral wall of the bag hole 2Bc toward the refrigerant. That is, by arranging the bag hole 2Bc, the heat exchange area in the intermediate path 23b is increased, thereby reducing the amount of heat transferred from the second enlarged diameter hole 23d to the power element 8. Therefore, the effects of heat from the high-pressure refrigerant passing through the second enlarged diameter hole 23d can be suppressed, enabling proper control of the power element 8.

[0110] The expansion valve of the present invention is capable of connecting a double-layer piping system, wherein a low-pressure refrigerant passes through the inner piping and a high-pressure refrigerant passes between the outer piping system disposed around the inner piping and the inner piping system. The expansion valve has:

[0111] The valve body has a low-pressure flow path for the low-pressure refrigerant to flow and a high-pressure flow path for the high-pressure refrigerant to flow;

[0112] A power element, which is mounted on the valve body; and

[0113] A heat transfer control unit that facilitates heat transfer between the power element and the low-pressure refrigerant flowing in the low-pressure flow path, or inhibits heat transfer between the power element and the high-pressure refrigerant flowing in the outer piping.

[0114] The heat transfer control unit is formed in a hole in the valve body between the power element and the double-layer piping connected to the valve body.

[0115] (Fourth Implementation)

[0116] Figure 5 This is a longitudinal sectional view of the expansion valve 1C according to the fourth embodiment. Compared to the first embodiment, this embodiment differs only in the shape of the valve body 2C. All other structures are the same as in the embodiments described above; therefore, the same symbols are used and repeated descriptions are omitted.

[0117] In this embodiment, the valve body 2C does not have a circumferential groove in the intermediate passage 23b. Instead, an annular groove 2Cc is formed on the upper end face of the valve body 2B around the longitudinal hole 2a. A portion of the annular groove 2Cc is located radially outside the first enlarged diameter hole 23c. The annular groove 2Cc constitutes a heat transfer control section.

[0118] According to this embodiment, since no annular groove 2Cc is formed radially outside the first enlarged diameter hole 23c between the longitudinal hole 2a and the second enlarged diameter hole 23d, the heat transfer path from the refrigerant entering the second enlarged diameter hole 23d to the power element 8 is narrowed, thereby reducing the amount of heat transferred to the power element 8. Therefore, the influence of heat generated by the high-pressure refrigerant passing through the second enlarged diameter hole 23d can be suppressed, and appropriate control operation of the power element 8 can be achieved.

[0119] The expansion valve of the present invention is capable of connecting a double-layer piping system, wherein a low-pressure refrigerant passes through the inner piping and a high-pressure refrigerant passes between the outer piping system disposed around the inner piping and the inner piping system. The expansion valve has:

[0120] The valve body has a low-pressure flow path for the low-pressure refrigerant to flow and a high-pressure flow path for the high-pressure refrigerant to flow;

[0121] A power element, which is mounted on the valve body; and

[0122] A heat transfer control unit that facilitates heat transfer between the power element and the low-pressure refrigerant flowing in the low-pressure flow path, or inhibits heat transfer between the power element and the high-pressure refrigerant flowing in the outer piping.

[0123] The heat transfer control unit is formed in a groove in the valve body between the power element and the double-layer piping connected to the valve body.

[0124] (Fifth Implementation)

[0125] Figure 6 This is a longitudinal sectional view of the expansion valve 1D according to the fifth embodiment. Figure 7 From Figure 6 The diagram shows the return flow path 23D of this embodiment viewed from the right side. Compared to the first embodiment, this embodiment differs only in the shape of the return flow path 23D of the valve body 2D. All other structures are the same as in the embodiments described above; therefore, the same symbols are used and repeated descriptions are omitted.

[0126] In the valve body 2D of this embodiment, the second enlarged bore 23Dd is divided into an eccentric bore (a third bore) 23D1 on the side of the first enlarged bore (a first bore portion) 23c and a coaxial bore (a second bore portion) 23D2 on the side of the third enlarged bore 23e. Figure 6 As shown, an eccentric hole 23D1 with a larger diameter than the first enlarged hole 23c is eccentrically positioned downwards relative to the first enlarged hole 23c, but a coaxial hole 23D2 with a larger diameter than the eccentric hole 23D1 is coaxial with the first enlarged hole 23c. When the axis of the first enlarged hole 23c is set to O1 and the axis of the eccentric hole 23D1 is set to O2, the distance between the axes is Δ1. Preferably, the upper end of the first enlarged hole 23c is at the same position as the upper end of the eccentric hole 23D1, and preferably, the lower end of the eccentric hole 23D1 is at the same position as the lower end of the coaxial hole 23D2. The end of the inner pipe 51 is fitted into the intermediate path 23b, and the end of the outer pipe 52 is fitted into the coaxial hole 23D2. The eccentric hole 23D1 constitutes a heat transfer control section.

[0127] The refrigerant supplied between the outer pipe 52 and the inner pipe 51 flows into the first flow path 21 after passing through the eccentric hole 23D1. According to this embodiment, since the eccentric hole 23D1 is offset away from the power element 8, the amount of heat transferred from the refrigerant entering the eccentric hole 23D1 to the power element 8 can be reduced. Therefore, the effects of heat generated by the high-pressure refrigerant can be suppressed, and proper control of the power element 8 can be achieved.

[0128] (Sixth Implementation Method)

[0129] Figure 8 This is a longitudinal sectional view of the expansion valve 1E according to the sixth embodiment. Figure 9 From Figure 8 The diagram shows the return flow path 23E of this embodiment viewed from the right side. Compared to the first embodiment, this embodiment differs only in the shape of the return flow path 23E of the valve body 2E. All other structures are the same as in the embodiments described above; therefore, the same symbols are used and repeated descriptions are omitted.

[0130] In the valve body 2E of this embodiment, the second enlarged bore (here, the second bore portion) 23Ed and the third enlarged bore 23Ee are eccentrically positioned downwards relative to the first enlarged bore (here, the first bore portion) 23c. When the axis of the first enlarged bore 23c is set to O1, and the axes of the second enlarged bore 23Ed and the third enlarged bore 23Ee are set to O3, the distance between the axes is Δ2. The distance between the axes Δ2 is larger than the distance between the axes Δ1 in the fifth embodiment. Preferably, the upper end of the first enlarged bore 23c is at the same position as the upper end of the second enlarged bore 23Ed. The end of the inner pipe 51 is fitted into the intermediate path 23b, and the end of the outer pipe 52 is fitted into the second enlarged bore 23Ed. Therefore, the outer pipe 52 of the double-layer pipe 50 is also eccentrically positioned downwards relative to the inner pipe 51. The second enlarged bore 23Ed constitutes a heat transfer control section.

[0131] The refrigerant supplied between the outer pipe 52 and the inner pipe 51 flows to the first flow path 21 after passing through the second enlarged orifice 23Ed. According to this embodiment, since the second enlarged orifice 23Ed is further offset away from the power element 8, the amount of heat transferred from the refrigerant entering the second enlarged orifice 23Ed to the power element 8 can be reduced. Therefore, the effects of heat generated by the high-pressure refrigerant can be suppressed, and appropriate control operation of the power element 8 can be achieved.

[0132] (Seventh Implementation)

[0133] Figure 10 This is a longitudinal sectional view of the expansion valve 1F according to the seventh embodiment. In this embodiment, a double-layer piping 50F, different from that in the embodiments described above, is incorporated into the valve body 2D of the fifth embodiment. Other than this, the structure is the same as in the embodiments described above; therefore, the same reference numerals are used and repeated descriptions are omitted.

[0134] The double-layer piping 50F has an inner piping 51F and an outer piping 52F. The outer piping 52F has the same structure as in the embodiment described above. On the other hand, the inner piping 51F is formed by continuously providing a circular tube 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-layer piping 50F constitutes a heat transfer control section.

[0135] When the inner pipe 51F is inserted into the outer pipe 52F, a spiral passage is formed along the spiral groove 51Fd by the contact between the outer peripheral surface of the spiral portion 51Fc and the inner peripheral surface of the outer pipe 52F. High-pressure refrigerant flows along this passage.

[0136] When the double-layer piping 50F is installed in the return flow path 23D of the valve body 2D, the end of the outer piping 52F is fitted into the coaxial hole 23D2, and the end of the inner piping 51F protruding from the outer piping 52F is fitted into the intermediate path 23b. The axis of the spiral portion 51Fc is aligned with the axis O1 of the return flow path 23D, but the axis of the circular tube portion 51Fb is eccentrically positioned upward relative to the axis O1 of the return flow path 23D. Therefore, when assembled in the valve body 2D, the upper part of the circular tube portion 51Fb contacts the inner circumferential surface of the eccentric hole 23D1.

[0137] The refrigerant supplied between the outer pipe 52F and the inner pipe 51F enters the lower side of the eccentric hole 23D1 through the spiral groove 51Fd and flows to the first flow path 21. At this time, heat transfer occurs from the high-pressure refrigerant passing through the spiral groove 51Fd to the low-pressure refrigerant passing through the inner pipe 51F. However, due to the increased heat transfer area caused by the spiral groove 51Fd, heat transfer from the high-pressure refrigerant to the low-pressure refrigerant is promoted during passage through the spiral groove 51Fd. Furthermore, since the upper outer circumferential surface of the circular tube portion 51b of the inner pipe 51F abuts against the eccentric hole 23D1, the upper periphery of the eccentric hole 23D1 is cooled by the refrigerant passing through the inner pipe 51F. Due to these combined effects, the influence of heat generated by the high-pressure refrigerant passing through the second enlarged diameter hole 23Fd can be suppressed, enabling appropriate control of the power element 8.

[0138] The expansion valve of the present invention is capable of connecting a double-layer piping system, wherein a low-pressure refrigerant passes through the inner piping and a high-pressure refrigerant passes between the outer piping system disposed around the inner piping and the inner piping system. The expansion valve has:

[0139] The valve body has a low-pressure flow path for the low-pressure refrigerant to flow and a high-pressure flow path for the high-pressure refrigerant to flow;

[0140] A power element, which is mounted on the valve body; and

[0141] A heat transfer control unit that facilitates heat transfer between the power element and the low-pressure refrigerant flowing in the low-pressure flow path, or inhibits heat transfer between the power element and the high-pressure refrigerant flowing in the outer piping.

[0142] The heat transfer control section is a spiral groove formed around the inner piping.

[0143] (Eighth Implementation)

[0144] Figure 11 This is a longitudinal sectional view of the expansion valve 1G according to the eighth embodiment. Figure 12This is a perspective view showing the valve body 2G of this embodiment divided into two parts and together with the annular component 60. Compared to the first embodiment, this embodiment differs only in the following point: a circumferential groove is not formed in the return flow path 23G of the valve body 2G, and the annular component 60 is provided. The structure otherwise is the same as the embodiment described above; therefore, the same reference numerals are used and repeated descriptions are omitted.

[0145] In this embodiment, the resin-made annular member 60 is disposed in a manner that fits into the inner circumference of the second enlarged diameter hole (in this case, the second hole portion) 23d. A cutout 60a is formed in a portion of the circumference of the annular member 60. The annular member 60 is disposed in the second enlarged diameter hole 23d such that the cutout 60a matches the first flow path (high-pressure flow path) 21. Thus, the inlet of the first flow path 21 is completely open, allowing the radially inner side of the annular member 60 to communicate with the first flow path 21 via the cutout 60a. Alternatively, an opening that connects the inner and outer circumferences of the annular member 60 may be provided instead of the cutout 60a.

[0146] The inner circumferential surface of the annular component 60 abuts against the outer circumferential surface of the flange portion 51a of the inner piping 51. Furthermore, the left end of the annular component 60 abuts against the stepped portion between the first enlarged diameter hole (here, the first hole portion) 23c and the second enlarged diameter hole 23d, and the right end of the annular component 60 abuts against the end of the outer piping 52. Preferably, the thickness of the annular component 60 is equal to the thickness of the outer piping 52. The annular component 60 constitutes a heat transfer control section.

[0147] The refrigerant supplied between the outer pipe 52 and the inner pipe 51 flows to the first flow path 21 through the cut 60a after entering the second expansion orifice 23d. According to this embodiment, a heat-insulating annular member 60 is disposed between the refrigerant entering the second expansion orifice 23d and the second expansion orifice 23d, thereby reducing the amount of heat transferred from the refrigerant entering the second expansion orifice 23d to the power element 8. This suppresses the effects of heat from the high-pressure refrigerant, enabling proper control of the power element 8. The annular member 60 can be used in conjunction with the embodiment described above.

[0148] The expansion valve of the present invention is capable of connecting a double-layer piping system, wherein a low-pressure refrigerant passes through the inner piping and a high-pressure refrigerant passes between the outer piping system disposed around the inner piping and the inner piping system. The expansion valve has:

[0149] The valve body has a low-pressure flow path for the low-pressure refrigerant to flow and a high-pressure flow path for the high-pressure refrigerant to flow;

[0150] A power element, which is mounted on the valve body; and

[0151] A heat transfer control unit that facilitates heat transfer between the power element and the low-pressure refrigerant flowing in the low-pressure flow path, or inhibits heat transfer between the power element and the high-pressure refrigerant flowing in the outer piping.

[0152] The valve body has a first hole and a second hole. The first hole is coaxial with the low-pressure flow path that is fitted into the inner piping. The second hole is connected to the high-pressure flow path and is coaxial with the first hole, and is fitted into the outer piping. A heat-insulating annular component is disposed in the second hole.

[0153] The annular component has a cut or opening, and the high-pressure flow path is connected to the second hole via the cut or opening.

[0154] Furthermore, the present invention is not limited to the embodiments described above. Within the scope of the present invention, any constituent elements of the above embodiments can be modified. Additionally, in the above embodiments, any constituent elements can be added or omitted.

Claims

1. An expansion valve capable of connecting a double-layer piping system, wherein a low-pressure refrigerant passes through an inner piping system and a high-pressure refrigerant passes between an outer piping system disposed around the inner piping system and the inner piping system, the expansion valve being characterized by having: The valve body has a low-pressure flow path for the low-pressure refrigerant to flow and a high-pressure flow path for the high-pressure refrigerant to flow; A power element, which is mounted on the valve body; and A heat transfer control unit that connects the outer piping to the valve body in an eccentric manner relative to the inner piping in the direction away from the power element, thereby suppressing heat transfer between the power element and the high-pressure refrigerant flowing in the outer piping.

2. The expansion valve according to claim 1, characterized in that, The heat transfer control unit has a first orifice and a second orifice. The first orifice is coaxial with the low-pressure flow path that is fitted into the inner piping, and the second orifice is fitted into the outer piping. The second orifice is eccentric to the side away from the power element relative to the first orifice.

3. The expansion valve according to claim 2, characterized in that, The end position of the first hole on the power element side is the same as the end position of the second hole.

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