Device and piping structure for use in vehicle refrigeration cycle

Abstract

To provide a vehicle refrigeration cycle that uses propane or carbon dioxide as a refrigerant, and improves the ability to prevent the refrigerant from leaking outside.SOLUTION: A device 1 comprises a first part 8 that has an attachment hole 22 communicating with a refrigerant passage 20, a second part 6 having an insertion portion 24 to be inserted into the attachment hole 22, and a double seal structure 30 including a first seal ring 31 and a second seal ring 33 that are respectively interposed on the opposing surfaces of the first part 8 and the second part 6, and forming a sealed space S1 between the first seal ring 31 and the second seal ring 33. The first seal ring 31 regulates communication between the refrigerant passage 20 and the sealed space S1, and the second seal ring 33 regulates communication between the sealed space S1 and the outside air. The second seal ring 33 is made of ethylene propylene diene rubber (EPDM), and the first seal ring 31 is made of a rubber having lower refrigerant permeability than the second seal ring 33.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a sealing structure for a device and a pipe used in a refrigeration cycle. [Background technology]

[0002] With the recent spread of electric vehicles, the development of their air conditioning systems is also progressing. Because electric vehicles do not have a heat source such as an internal combustion engine, they employ heat pump-type air conditioning systems that use a refrigerant for cycle operation for both cooling and heating (see Patent Document 1).

[0003] Such heating and cooling systems have a refrigeration cycle that includes devices such as a compressor, an outdoor heat exchanger, an expansion device, an evaporator, and an indoor heat exchanger, and the refrigerant circulation path is switched between heating and cooling operation. Because multiple refrigerant circulation paths are formed, the number of pipes for forming and connecting these refrigerant circulation paths and the number of devices such as control valves installed in the refrigerant circulation paths tend to increase. Therefore, it is important to take measures to prevent refrigerant leakage (also known as "external leakage") from each device and piping connection.

[0004] Meanwhile, in recent years, as part of measures to combat global warming, fluorinated refrigerants with low ozone depletion potential and global warming potential (such as HFO-1234yf) have been adopted, but a switch to natural refrigerants with a lower environmental impact is also being considered. For example, propane and carbon dioxide are known to be natural refrigerants with relatively high refrigeration effects. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-11578 Summary of the Invention [Problem to be solved by the invention]

[0006] However, refrigerants that are primarily composed of hydrocarbons, such as propane, are highly flammable (i.e., highly combustible), and therefore may ignite if they leak under high temperatures and pressures. Furthermore, carbon dioxide leaks can cause poisoning. For this reason, the selection of sealing materials (such as O-rings) used to prevent external leaks as mentioned above becomes even more important.

[0007] In this regard, if hydrogenated nitrile rubber (HNBR), a typical sealing material, is used, its sealing function will be sufficient under normal temperature conditions. However, when a vehicle is used in extremely cold regions and placed at extremely low temperatures (for example, below -30°C), the sealing function may be reduced. In other words, at extremely low temperatures, the saturation pressure of propane and carbon dioxide is maintained at a positive pressure, while the HNBR hardens, which reduces the sealing performance of the sealing material and creates gaps in the sealed area, potentially resulting in external leakage.

[0008] An object of the present invention is to improve the ability to prevent refrigerant from leaking outside in a vehicle refrigeration cycle that uses propane or carbon dioxide as a refrigerant. [Means for solving the problem]

[0009] One aspect of the present invention is a device applicable to a vehicle refrigeration cycle that uses propane or carbon dioxide as a refrigerant. The device includes: a first component having a refrigerant passage through which the refrigerant flows and a mounting hole communicating with the refrigerant passage; a second component having an insertion portion that is attached to be inserted into the mounting hole and that closes the mounting hole when the insertion portion is attached to the mounting hole; and a double seal structure including a first seal ring and a second seal ring that are respectively interposed on opposing surfaces of the first component and the second component, forming a sealed space between the first seal ring and the second seal ring. The first seal ring regulates communication between the refrigerant passage and the sealed space, and the second seal ring regulates communication between the sealed space and the outside air. The second seal ring is made of ethylene propylene diene rubber (EPDM), and the first seal ring is made of a rubber that has lower refrigerant permeability than the second seal ring.

[0010] According to this embodiment, a double-seal structure consisting of a first seal ring and a second seal ring is provided to prevent external leakage through the gap between the first and second components. The second seal ring is made of EPDM, which is permeable to propane and carbon dioxide, while the first seal ring is made of rubber, which is less permeable to propane and carbon dioxide. Therefore, the first seal ring can fully perform its sealing function as long as the vehicle is kept in a normal temperature environment. On the other hand, even if the vehicle is kept in an extremely low temperature environment and the first seal ring hardens and its sealing function is reduced, the second seal ring can still perform its sealing function because EPDM has excellent cold resistance. Because the pressure of propane and carbon dioxide is low at extremely low temperatures, the pressure difference between the refrigerant pressure and atmospheric pressure, i.e., the pressure pushing the refrigerant from the inside of the device to the outside, is small. Therefore, even though EPDM is refrigerant permeable, the sealing performance of the second seal ring can fully prevent external leakage.

[0011] Another aspect of the present invention is a piping structure applicable to a vehicle refrigeration cycle using propane or carbon dioxide as a refrigerant. This piping structure includes: a first pipe having a refrigerant passage through which the refrigerant flows; a second pipe having an insertion part attached to one end of the first pipe and forming a refrigerant circulation passage of the refrigeration cycle together with the first pipe by attaching the insertion part to the one end; and a double seal structure including a first seal ring and a second seal ring respectively interposed on opposing surfaces of the first pipe and the second pipe, forming a sealed space between the first seal ring and the second seal ring. The first seal ring regulates communication between the refrigerant passage and the sealed space, and the second seal ring regulates communication between the sealed space and the outside air. The second seal ring is made of ethylene propylene diene rubber (EPDM), and the first seal ring is made of a rubber with lower refrigerant permeability than the second seal ring.

[0012] According to this embodiment, a double-seal structure consisting of a first seal ring and a second seal ring is provided to prevent external leakage through the gap between the first and second pipes. The second seal ring is made of EPDM, which is permeable to propane and carbon dioxide, while the first seal ring is made of rubber, which is less permeable to propane and carbon dioxide. Therefore, the first seal ring can fully perform its sealing function as long as the vehicle is kept in a normal temperature environment. On the other hand, even if the vehicle is kept in an extremely low temperature environment and the first seal ring hardens and its sealing function is reduced, the second seal ring can still perform its sealing function because EPDM has excellent cold resistance. Because the pressure of propane and carbon dioxide is low at extremely low temperatures, the pressure difference between the refrigerant pressure and atmospheric pressure, i.e., the pressure pushing the refrigerant from the inside of the pipe to the outside, is small. Therefore, even though EPDM is refrigerant permeable, the sealing performance of the second seal ring can fully prevent external leakage. [Effects of the Invention]

[0013] According to the present invention, in a vehicle refrigeration cycle that uses propane or carbon dioxide as a refrigerant, the performance of preventing the refrigerant from leaking to the outside can be improved. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a cross-sectional view illustrating a motor-operated valve according to a first embodiment. [Figure 2] FIG. 2 is an enlarged view of part A in FIG. [Figure 3] FIG. 4 is a diagram illustrating the operation of the motor-operated valve. [Figure 4] FIG. 6 is a cross-sectional view showing a motor-operated valve according to a second embodiment. [Figure 5] FIG. 5 is an enlarged view of part A in FIG. 4. [Figure 6] FIG. 10 is a cross-sectional view showing a piping structure according to a third embodiment. [Figure 7] FIG. 10 is a cross-sectional view schematically illustrating a device according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. For convenience, the following description may refer to the positional relationship of each structure based on the illustrated state. In the following embodiments and their modifications, substantially identical components will be designated by the same reference numerals, and their description will be omitted where appropriate.

[0016] [First embodiment] FIG. 1 is a cross-sectional view showing the motor-operated valve according to the first embodiment. The motor-operated valve 1 is one of the devices applied to a vehicle refrigeration cycle (not shown). The refrigeration cycle is equipped with a compressor, an external heat exchanger, an expansion valve, an evaporator, etc., and the refrigerant circulation passage is switched depending on the operating state of the air conditioning system. The high-temperature, high-pressure refrigerant compressed by the compressor is cooled by passing through the external heat exchanger. The refrigerant then adiabatically expands as it passes through the expansion valve, becoming low-temperature and low-pressure, and is then guided to the evaporator where it evaporates. The latent heat of evaporation cools the air inside the vehicle cabin.

[0017] In this embodiment, with consideration for the global environment in mind, propane (R290) is used as the refrigerant, which has a relatively high refrigeration effect among natural refrigerants and a low global warming potential. As mentioned above, propane is highly flammable, so measures to prevent external leakage are necessary. Therefore, a double seal structure using two seal rings is provided in the motor-operated valve 1 at locations where external leakage is a concern. The details of this structure are described below.

[0018] The motor-operated valve 1 is a composite valve that has a large-diameter first valve 2 (large-diameter valve) and a small-diameter second valve 4 (small-diameter valve) arranged coaxially, and these valves are driven by a common motor. The first valve 2 functions as an on-off valve, and the second valve 4 functions as an expansion valve.

[0019] The motor-operated valve 1 is configured by assembling a valve unit 6 and a passage body 8. The passage body 8 functions as a "first component," and the valve unit 6 functions as a "second component." The valve unit 6 includes a rotor unit 10 and a stator unit 12. The rotor unit 10 and the stator unit 12 are each fixed to the passage body 8. The rotor unit 10 is fastened to the passage body 8 via a screw structure. The stator unit 12 is fixed to the passage body 8 via a connecting member 14. The connecting member 14 includes a metal plate fixed to the stator unit 12 and a screw for fixing the metal plate to the passage body 8.

[0020] The passage body 8 is made of a metal such as an aluminum alloy and has a generally rectangular columnar shape. An inlet port 16 opens at the bottom of one side of the passage body 8, and an outlet port 18 opens at the top of the opposite side. A refrigerant passage 20 is formed in the passage body 8, connecting the inlet port 16 and the outlet port 18. Refrigerant from the upstream side is introduced into the refrigerant passage 20 through the inlet port 16, passes through a valve portion, and is then discharged downstream from the outlet port 18. A stepped circular mounting hole 22 is formed in the center of the upper half of the passage body 8, and communicates with the refrigerant passage 20. A female thread 23 is formed in the mounting hole 22.

[0021] The rotor unit 10 has a valve body 24 that houses a valve portion. In this embodiment, the valve body 24 is made of stainless steel (hereinafter referred to as "SUS"). A valve seat member 26 is provided at the lower end of the valve body 24, and a seal ring 28 (O-ring) is attached to the outer peripheral surface of the valve seat member 26. A male thread 25 that can be threadedly engaged with the female thread 23 is formed on the outer peripheral surface of the valve body 24. When assembling the rotor unit 10 to the passage body 8, the valve body 24 is inserted into the mounting hole 22. The male thread 25 is threadedly engaged with the female thread 23, and the valve body 24 is fastened to the passage body 8.

[0022] The valve body 24 functions as an "insertion part" that is attached so that its tip side is inserted into the attachment hole 22, and when the valve body 24 is attached to the attachment hole 22, the valve unit 6 closes the attachment hole 22. The valve body 24 and the passage body 8 can also be interpreted together as the "body of the motor-operated valve 1."

[0023] A double seal structure 30 consisting of upper and lower seal rings 31 and 33 is provided on the upper outer peripheral surface of the valve body 24 (slightly above the male thread 25). The seal ring 31 functions as the "first seal ring," and the seal ring 33 functions as the "second seal ring." These seal rings 31 and 32 are interposed between the opposing surfaces of the mounting hole 22 and the valve body 24, more specifically, between the inner peripheral surface of the mounting hole 22 and the outer peripheral surface of the valve body 24, thereby preventing refrigerant leakage from the inside to the outside of the passage body 8 (external leakage). The materials of the two seal rings 31 and 33 are selected so that the double seal structure 30 is particularly effective when propane is used as the refrigerant, as in this embodiment (details will be described later).

[0024] A first valve element 32 is housed in the lower half of the valve body 24 and is supported so as to be slidable in the axial direction. A first valve hole 34 is formed inside the valve seat member 26 and is coaxial with the mounting hole 22. A first valve seat 36 is formed at the downstream open end of the first valve hole 34. The first valve element 32 is attached to and detached from the first valve seat 36 to open and close the first valve 2.

[0025] An internal passage is formed in the first valve element 32, and a second valve hole 38 is formed in the middle of the internal passage. A second valve seat 40 is formed at the upstream open end of the second valve hole 38. An actuation rod 42 extending from the rotor 60 of the rotor unit 10 is inserted into the interior of the valve body 24. The lower part of the actuation rod 42 is inserted coaxially into the first valve element 32. The actuation rod 42 is obtained by cutting a rod made of a non-magnetic metal, and a needle-shaped second valve element 44 is integrally formed at the lower part. The second valve element 44 opens and closes the second valve 4 by being attached to and detached from the second valve seat 40 from the upstream side. That is, the second valve element 44 is provided so as to be displaceable integrally with the actuation rod 42, and moves toward or away from the second valve hole 38 from the side opposite the first valve hole 34, and opens and closes the second valve 4 by being attached to and detached from the second valve seat 40.

[0026] A guide member 46 that slidably supports the operating rod 42 is erected at the center of the upper part of the valve body 24. The lower end of the guide member 46 has a large diameter, and a large-diameter portion 48 of this guide member 46 is press-fitted into the center of the upper part of the valve body 24 and fixed coaxially. An internal thread 50 is provided on the inner peripheral surface of the guide member 46 to rotatably and slidably support the operating rod 42.

[0027] The actuation rod 42 is a stepped cylindrical member, and a male thread 52 is formed on the outer peripheral surface of the upper half thereof, which meshes with a female thread 50 of the guide member 46. A screw feed mechanism 54 using these screws converts the rotational motion of the rotor 60 into translational motion (axial motion) of the actuation rod 42. This causes the second valve body 44 to move (raise and lower) in the axial direction, i.e., in the opening and closing direction of the valve portion.

[0028] Meanwhile, the rotor 60 of the rotor unit 10 and the stator 62 of the stator unit 12 constitute a two-phase stepping motor. The rotor unit 10 has a cylindrical can 64 with a bottom, and the rotor 60 is disposed inside the can 64. The stator 62 is disposed outside the can 64. The can 64 is a cylindrical member with a bottom that covers the space in which the second valve body 44 and its drive mechanism are disposed and that contains the rotor 60, and defines an inner pressure space (internal space) where the pressure of the refrigerant acts and an outer non-pressure space (external space) where the pressure of the refrigerant does not act.

[0029] The rotor 60 includes a stepped cylindrical rotor core 66 coaxially mounted on the upper part of the actuation rod 42, a rotor magnet 68 coaxially mounted on the outer circumferential surface of the rotor core 66, and a sensor magnet 70 provided on the upper end surface of the rotor core 66. The rotor magnet 68 is cylindrical, and its upper end is fixed so as to fit into the outer circumferential surface of the rotor core 66. With this configuration, a relatively large annular space S is formed between the inner circumferential surface of the rotor magnet 68 and the outer circumferential surface of the actuation rod 42.

[0030] The sensor magnet 70 has an annular shape and is coaxially attached to the rotor core 66. The rotor magnet 68 is magnetized (magnetized) with multiple poles in the circumferential direction. The sensor magnet 70 is also magnetized (magnetized) with multiple poles.

[0031] The stator 62 is configured by assembling a bobbin 74 around which the coil 72 is wound to a yoke 76 having a plurality of pole teeth. The stator 62 is provided integrally with a case 78 of the stator unit 12. That is, the case 78 is obtained by injection molding (also called "insert molding" or "mold molding") of a corrosion-resistant resin material. The stator 62 is covered with the molded resin obtained by the injection molding. The stator unit 12 is a molded product of the stator 62 and the case 78.

[0032] The stator unit 12 has a hollow structure and is assembled to the passage body 8 with the can 64 coaxially inserted therethrough. A seal ring 80 (O-ring) is fitted onto the outer peripheral surface of the upper part of the valve body 24. By interposing the seal ring 80 between the valve body 24 and the case 78, the external atmosphere (water, etc.) is prevented from entering the gap between the can 64 and the stator 62.

[0033] The stator unit 12 has a circuit board 82 on the outside of the can 64. The circuit board 82 is fixed inside the case 78. Various circuits that function as a control unit and a communication unit are mounted on the underside of the circuit board 82. Specifically, a drive circuit for driving the motor, a control circuit (microcomputer) that outputs control signals to the drive circuit, a communication circuit for the control circuit to communicate with an external device, a power supply circuit for supplying power to each circuit and the motor (coil 72), etc. are mounted on the circuit board 82. The upper end of the case 78 is closed by a lid 84. The circuit board 82 is disposed in the space below the lid 84 of the case 78.

[0034] A magnetic sensor 85 is provided on the surface of the circuit board 82 facing the sensor magnet 70. The magnetic sensor 85 faces the sensor magnet 70 in the axial direction via the bottom end wall of the can 64. The magnetic flux generated by the sensor magnet 70 changes as the rotor 60 rotates. The magnetic sensor 85 detects the amount of displacement of the rotor 60 (the rotation angle of the rotor 60 in this embodiment) by detecting this change in magnetic flux. The control unit calculates the axial position of the second valve body 44 and therefore the opening degree of the second valve 4 based on the amount of displacement of the rotor 60.

[0035] Terminals 86 connected to the coil 72 extend from the bobbin 74 and are connected to the circuit board 82. A power terminal, a ground terminal, and a communication terminal (collectively referred to as "connection terminals 88") extend from the circuit board 82 and are each drawn out to the outside through the side wall of the case 78. A connector portion 90 is integrally provided on the side of the case 78, and the connection terminals 88 are arranged inside the connector portion 90.

[0036] FIG. 2 is an enlarged view of part A in FIG. The valve body 24 is formed by coaxially assembling a valve housing 100, a guide member 102, and a valve seat member 26. The valve housing 100 is a stepped cylinder, and seal rings 31, 33, and 80 are fitted onto its outer circumferential surface. A male thread 25 is formed at the lower end of the valve housing 100. A guide member 46 is assembled to the center of the upper part of the valve housing 100.

[0037] The guide member 102 is obtained by applying lubrication plating to a stepped cylindrical member made of stainless steel. Known lubrication plating materials, such as nickel-phosphorus (Ni-P) containing polytetrafluoroethylene (hereinafter referred to as "PTFE"), can be used as the lubrication plating material. This type of surface treatment of the sliding surface also reduces sliding resistance.

[0038] The upper end of the guide member 102 is press-fitted into the lower end of the valve housing 100, and the upper end of the valve seat member 26 is press-fitted into the lower end of the guide member 102, thereby coaxially integrating the valve housing 100, guide member 102, and valve seat member 26. A communication hole 104 that communicates the inside and outside is provided in the side of the guide member 102. A guide hole 106 is formed by the inner circumferential surface of the upper part of the guide member 102. The guide hole 106 is provided coaxially with the first valve hole 34.

[0039] The first valve body 32 is cylindrical and has a bottom, and is slidably supported in the guide hole 106. The first valve body 32 is cylindrical and has a bottom with a sufficient thickness. A back pressure chamber 108 is formed above the first valve body 32. The back pressure chamber 108 is a space surrounded by the guide member 46, the valve housing 100, and the first valve body 32. A valve chamber 110 is formed inside the first valve body 32 (above the bottom). A stepped disc-shaped operating connecting member 112 is coaxially inserted and fixed to the top of the first valve body 32.

[0040] The actuation connecting member 112 has an insertion hole 114 in the center of its bottom. The actuation rod 42 passes coaxially through the insertion hole 114. The actuation connecting member 112 is provided with a plurality of communication holes 116 that communicate between the inside and outside of the first valve body 32. The communication holes 116 communicate between the valve chamber 110 and the back pressure chamber 108. The actuation connecting member 112 is fixed to the first valve body 32 by fitting its upper end opening into the upper end opening of the first valve body 32 and caulking the protrusion on the periphery of the upper end opening of the first valve body 32 inward.

[0041] An annular seal receiving portion 120 that opens radially inward is formed between the valve housing 100 and the guide member 102. Double seal rings 122, 124 are fitted into the seal receiving portion 120. The seal ring 122 is an O-ring with a circular cross section, and the seal ring 124 is a square ring with a rectangular cross section. The seal ring 124 is disposed so as to be inscribed within the seal ring 122. The outer peripheral surface of the seal ring 122 is in close contact with the inner peripheral surface of the valve housing 100 and the upper end surface of the guide member 102, and the inner peripheral surface of the seal ring 124 is in close contact with the outer peripheral surface of the first valve body 32.

[0042] The seal ring 124 is made of PTFE, has high lubrication performance and appropriate elasticity (flexibility), and slidably supports the first valve body 32. In this embodiment, the seal ring 124 has an inner diameter slightly smaller than that of the guide hole 106 and primarily supports the first valve body 32. The guide hole 106 has an inner diameter slightly larger than that of the first valve body 32 and suppresses axial wobble of the first valve body 32. The seal ring 124 prevents or suppresses refrigerant leakage through the clearance between the guide member 102 and the first valve body 32.

[0043] A spring 126 (functioning as a "first biasing member") that biases the first valve body 32 in the valve closing direction is interposed between the valve housing 100 and the first valve body 32. A spring 128 (functioning as a "second biasing member") that biases the second valve body 44 in the valve closing direction is interposed between the guide member 46 and the operating rod 42.

[0044] A radially protruding locking portion 129 is provided on the actuation rod 42 slightly above the second valve body 44. The locking portion 129 is formed, for example, of an E-ring. By hooking this locking portion 129 onto the first valve body 32 (the actuation connecting member 112), the first valve body 32 can be pulled up in the valve-opening direction against the biasing force of the spring 126. A mechanism that operatively connects the first valve body 32 and the actuation rod 42 (i.e., the second valve body 44) in this way so that they can be displaced together is called an "actuation connecting mechanism."

[0045] The operating connection member 112 also functions as a spring bearing that supports the spring 126. The biasing force of the spring 126 is transmitted to the first valve body 32 via the operating connection member 112. Furthermore, when the second valve body 44 is opened, the locking portion 129 is displaced relative to the first valve body 32 and comes into contact with the bottom surface of the operating connection member 112, pushing it up, thereby operating the first valve body 32 in the valve opening direction.

[0046] The can 64 is made of the same type of non-magnetic metal (SUS in this embodiment) as the valve housing 100, and is assembled coaxially with its lower part fitted onto the upper end of the valve housing 100. The valve body 24 and the can 64 are fixed and sealed together by applying a full-circumference weld (not shown) along the boundary between the lower end of the can 64 and the valve housing 100. The space surrounded by the valve body 24 and the can 64 forms the above-mentioned pressure space.

[0047] By making the guide member 102 a separate component from the valve housing 100, the welded part (valve housing 100) and the lubricant-coated part (guide member 102) can be produced separately. This simplifies the manufacturing process, as it is sufficient to simply immerse the entire guide member 102 material in a plating solution, without having to take the time to paint or vapor-deposit a plating film on the guide hole 106.

[0048] A plurality of communication holes 130 (small holes) are provided through the bottom of the first valve body 32 in a direction parallel to the axis (only one is shown in the figure). The lower end openings of these communication holes 130 serve as inlet ports 132. The communication holes 130 communicate between the upstream side of the first valve seat 36 in the first valve hole 34 and the valve chest 110. The communication holes 130, the valve chest 110, and the communication hole 116 form a "communication passage" that communicates between the upstream side of the first valve seat 36 and the back pressure chamber 108. This communication passage communicates between the valve chest 110 and the first valve hole 34 at a position different from that of the second valve hole 38.

[0049] A downstream passage 134 extending perpendicular to the axis is provided at the bottom of the first valve body 32. The downstream passage 134 has an outlet port 136 that opens toward the outlet port 18 side.

[0050] The second valve hole 38 communicates between the valve chamber 110 and the downstream passage 134. The communication hole 130 is disposed so as not to intersect with the downstream passage 134. The flow path cross section of the downstream passage 134 is sufficiently larger than the flow path cross section of the communication hole 130. The multiple communication holes 130, the valve chamber 110, the second valve hole 38, and the downstream passage 134 form an internal passage of the first valve body 32. The tip of the second valve body 44 passes through the second valve hole 38, and is attached to and detached from the second valve seat 40 by its tapered surface.

[0051] When the first valve 2 is closed or slightly opened as shown in the figure, the pressure on the upstream side of the first valve seat 36 (upstream pressure P1) is higher than the pressure on the downstream side of the first valve seat 36 (downstream pressure P2). Meanwhile, because the back pressure chamber 108 communicates with the upstream side of the first valve seat 36 via the valve chamber 110 and the communication hole 130, the pressure in the back pressure chamber 108 (also referred to as "back pressure") is approximately equal to the upstream pressure P1. As a result, the fluid pressure acting on the first valve body 32 is almost canceled out.

[0052] In this embodiment, to improve the valve closing performance of the first valve 2, the effective pressure-receiving diameter d1 of the sliding portion of the first valve element 32 is slightly larger than the seal portion diameter d2 of the detachable portion of the first valve element 32 (d1 > d2). The effective pressure-receiving diameter d1 is the outer diameter of the sliding portion of the first valve element 32 relative to the guide hole 106 or the seal ring 124. The seal portion diameter d2 is the outer diameter of the portion of the first valve element 32 where it is detachable from the first valve seat 36. However, because the difference in diameter is minimal, as described above, the fluid pressure acting on the first valve element 32 is almost canceled out. This reduces the resistance when the first valve element 32 is pulled in the valve opening direction, and reduces the rotational torque (rotational driving force) of the motor required to open the first valve 2. This pressure-receiving structure of the first valve element 32 is called a "back pressure cancellation structure."

[0053] Meanwhile, a pressure difference (P1-P2) between the upstream pressure P1 and the downstream pressure P2 occurs in the gap between the first valve body 32 and the guide hole 106. In this regard, in this embodiment, the seal rings 122 and 124 are provided to prevent refrigerant from leaking through the gap.

[0054] The upper portion of the actuation rod 42 is provided with a notch 140 (a so-called H-cut structure) having a pair of surfaces parallel to the axis. Meanwhile, an insertion hole of a shape complementary to the notch 140 is provided along the axis of the rotor core 66, and the notch 140 is inserted and fitted into the notch 140. A push nut 142 is press-fitted into the upper end of the actuation rod 42, preventing the actuation rod 42 from separating from the rotor core 66. In this manner, the actuation rod 42 and the rotor core 66 are coaxially assembled. The fitting structure between the notch 140 and the insertion hole provides a "restriction structure" that restricts rotation of the actuation rod 42 relative to the rotor 60. The actuation rod 42 functions as a rotation shaft of the rotor 60. While the embodiment employs an H-cut structure as the restriction structure, a D-cut structure or other anti-rotation structure may also be employed.

[0055] Next, the double seal structure 30 of this embodiment will be described in detail. The double seal structure 30 is a two-stage seal structure that includes a lower seal ring 31 and an upper seal ring 33, which are coaxially arranged. The seal rings 31 and 33 are O-rings of the same shape but are made of different materials. The seal ring 31 is made of hydrogenated nitrile rubber (HNBR), and the seal ring 33 is made of ethylene propylene diene rubber (EPDM).

[0056] HNBR is less permeable to the refrigerant propane than EPDM (its refrigerant permeability is low), but when placed in extremely low temperatures, such as -30°C or below, it hardens, resulting in a loss of sealing performance. On the other hand, EPDM is more permeable to propane than HNBR, but is less likely to harden even when placed in extremely low temperatures, meaning its sealing performance is less likely to be degraded. This embodiment utilizes these material properties to prevent external leakage of propane.

[0057] That is, the seal ring 31 is disposed closer to the tip of the valve body 24 than the seal ring 33, i.e., closer to the inside of the mounting hole 22. The seal ring 33 is disposed farther from the tip of the valve body 24 than the seal ring 31, i.e., closer to the open end of the mounting hole 22. As a result, a sealed space S1 is formed between the seal ring 31 and the seal ring 33 in the gap between the inner circumferential surface of the mounting hole 22 and the outer circumferential surface of the valve body 24.

[0058] With this configuration, the seal ring 31 restricts communication between the refrigerant passage 20 and the sealed space S1, and the seal ring 33 restricts communication between the sealed space S1 and the outside air (atmosphere). When a vehicle is placed in a normal temperature environment, the refrigerant pressure (i.e., the pressure of the propane) during operation of the refrigeration cycle is sufficiently greater than the atmospheric pressure. Therefore, a relatively large pressure difference acts across the double seal structure 30, but the HNBR does not harden, and the seal ring 31 fully demonstrates its sealing performance. Because HNBR has low refrigerant permeability, propane is also sufficiently prevented from permeating the seal ring 31 and leaking into the sealed space S1. Even if a small amount of propane permeates the seal ring 31 and leaks into the sealed space S1, the presence of the seal ring 33 prevents or sufficiently reduces external leakage.

[0059] On the other hand, when a vehicle is placed in an extremely low temperature (for example, -30°C or below), the HNBR hardens, which may reduce the sealing performance of the seal ring 31 and result in the formation of a gap. However, at extremely low temperatures, the pressure of the refrigerant circulating through the refrigeration cycle (i.e., the pressure of the propane) is low, and the differential pressure acting before and after the double seal structure 30 is small. Therefore, even if propane leaks into the sealed space S1, the amount can be kept small. Furthermore, the seal ring 33 is located beyond the sealed space S1. Even though the EPDM of the seal ring 33 is refrigerant permeable, the small differential pressure before and after the seal ring 33 sufficiently suppresses propane permeation.

[0060] Next, the operation of the motor-operated valve 1 will be described. 3A to 3C are diagrams illustrating the operation of the motor-operated valve 1. FIGS. 3A to 3C show the operation processes of the first valve 2 and the second valve 4.

[0061] When the motor is driven to rotate the rotor 60 in the forward direction and move the actuating rod 42 upward, the actuating rod 42 is displaced axially relative to the first valve body 32, the second valve body 44 is separated from the second valve seat 40, and the second valve 4 opens (FIGS. 3A and 3B). At this time, the communication hole 130, the valve chamber 110, the second valve hole 38, and the downstream passage 134 communicate with each other. Refrigerant from the upstream side flows through the internal passage of the first valve body 32 and is discharged downstream via the second valve 4. The second valve 4 can be made to function as an expansion valve by adjusting the opening of the second valve 4 to a predetermined degree.

[0062] When the actuation rod 42 is further actuated in the valve opening direction, and the displacement of the actuation rod 42 from the closed state of the second valve 4 reaches or exceeds a predetermined value, the locking portion 129 engages with the actuation connecting member 112, and the actuation rod 42 and the first valve body 32 are operatively connected (FIG. 3(C)). The actuation rod 42 then pulls up the first valve body 32 against the biasing force of the spring 126. This causes the first valve body 32 to separate from the first valve seat 36, and the first valve 2 opens. The refrigerant flows downstream via both the first valve 2 and the second valve 4. At this time, a large flow rate of refrigerant can be allowed to flow, but the flow rate can be adjusted by adjusting the opening of the first valve 2.

[0063] On the other hand, when the motor is driven to rotate the rotor 60 in the reverse direction, the actuating rod 42 moves downward. At this time, the first valve body 32 moves in the valve closing direction while maintaining the operative connection with the actuating rod 42 due to the biasing force of the spring 126. First, the first valve body 32 seats on the first valve seat 36, and the first valve 2 enters the valve closed state. When the actuating rod 42 is further actuated in the valve closing direction, the locking portion 129 disengages from the operative connection member 112, and the operative connection between the actuating rod 42 and the first valve body 32 is released. Thereafter, the second valve body 44 seats on the second valve seat 40, and the second valve 4 enters the valve closed state.

[0064] As described above, the motor-operated valve 1 of this embodiment is provided with a double seal structure 30 consisting of seal rings 31 and 33 to prevent external leakage of propane through the gap between the valve unit 6 and the passage body 8. While seal ring 33 is made of EPDM, which is permeable to propane, seal ring 31 is made of rubber, which is difficult for propane to permeate. Therefore, as long as the vehicle is kept in a normal temperature environment, seal ring 31 can fully perform its sealing function.

[0065] On the other hand, EPDM has excellent cold resistance, so even if the vehicle is placed in extremely low temperatures and seal ring 31 hardens, reducing its sealing function, seal ring 33 will still provide its sealing function. At extremely low temperatures, the pressure of propane itself is low, so the pressure difference between the refrigerant pressure and atmospheric pressure, i.e., the pressure that pushes the refrigerant out of the motor-operated valve 1, is small. For this reason, even though EPDM is refrigerant permeable, the sealing performance of seal ring 33 is sufficient to prevent external leakage.

[0066] [Second embodiment] FIG. 4 is a cross-sectional view showing the motor-operated valve according to the second embodiment. This embodiment differs from the first embodiment in that the motor-operated valve 201 is not a combined valve, but has only a small-diameter valve. The motor-operated valve 201 is configured by assembling a valve unit 206 and a passage body 208. The passage body 208 functions as the "first component," and the valve unit 206 functions as the "second component." The valve unit 206 includes a rotor unit 210 and a stator unit 12. The rotor unit 210 includes a valve element 44 provided at the tip of an actuation rod 242. The valve element 44 moves toward or away from the valve seat 40 to adjust the opening degree of the valve portion 204.

[0067] FIG. 5 is an enlarged view of part A in FIG. The rotor unit 210 includes a valve body 224 and a rotor 260. The valve body 224 is formed by coaxially assembling a valve housing 226 and a valve seat member 228. The valve seat member 228 is provided with a valve seat 40. The valve housing 226 has better weldability than the valve seat member 228, and the valve seat member 228 has better processability than the valve housing 226.

[0068] The valve housing 226 has an integral large-diameter portion 223 and a small-diameter portion 225, and is a stepped cylinder whose outer diameter decreases downward. A seal ring 80 is fitted onto the outer peripheral surface of the large-diameter portion 223, and a seal ring 28 is fitted onto the outer peripheral surface of the lower part of the valve seat member 228. A valve hole 38 is provided so as to axially pass through the bottom of the valve seat member 228, and a valve seat 40 is formed at the upper opening of the valve hole 38.

[0069] A circular hole-shaped recessed fitting portion 229 is provided in the lower part of the valve housing 226. The valve seat member 228 is cylindrical with a bottom, and its upper part is inserted into the recessed fitting portion 229. The lower end of the valve housing 226 is crimped radially inward, thereby fixing the valve seat member 228 to the valve housing 226. A male thread 25 is formed on the outer peripheral surface of the lower part of the valve housing 226.

[0070] A communication hole 104 that connects the inside and outside is provided in the side of the valve seat member 228. The communication hole 104 communicates with the outlet port 18 (see FIG. 4). A valve chamber 240 is formed inside the valve housing 226 and the valve seat member 228. An actuation rod 242 extending from the rotor 260 is inserted into the inside of the valve body 224. A valve element 44 is provided integrally with the lower part of the actuation rod 242. The valve element 44 is attached to and detached from the valve seat 40 from the valve chamber 240 side to open and close the valve portion 204. A cylindrical filter 248 is provided in the lower half of the mounting hole 22 so as to surround 104 and prevent foreign matter from entering the valve portion 204 from the upstream side.

[0071] A guide member 246 is erected at the top center of the valve housing 226. A male thread 52 is formed on the outer peripheral surface of the axial center of the guide member 246. Meanwhile, a cylindrical rotating shaft 262 with a bottom is provided inside the rotor 260. A female thread 50 is formed on the inner peripheral surface of the rotating shaft 262. The rotating shaft 262 is fitted onto the guide member 246 with its open end facing downward. The upper end of the rotating shaft 262 is press-fitted into the rotor core 266. That is, in this embodiment, the rotating shaft 262 is provided inside the rotor core 266, and the operating rod 242 is provided inside the rotating shaft 262.

[0072] The upper portion of the actuation rod 242 has a reduced diameter, and the reduced diameter portion 250 penetrates the bottom portion 252 of the rotary shaft 262. An annular stopper 254 (push nut) is fixed to the tip of the reduced diameter portion 250. Meanwhile, a spring 256 that urges the actuation rod 242 downward (i.e., in the valve closing direction) is interposed between the base end of the reduced diameter portion 250 and the bottom portion 252. With this configuration, when the valve is opened, the actuation rod 242 is displaced integrally with the rotor 260 with the stopper 254 engaged with the bottom portion 252. Meanwhile, when the valve is closed, the spring 256 is compressed by the reaction force that the valve element 44 receives from the valve seat 40. The elastic reaction force of the spring 256 at this time presses the valve element 44 against the valve seat 40, improving the seating performance (valve closing performance) of the valve element 44.

[0073] In this embodiment, too, a double seal structure 230 consisting of seal rings 31 and 33 is provided on the opposing surfaces of the passage body 208 and the valve unit 206, but the arrangement of these seal rings differs from that of the first embodiment. The seal ring 31 is interposed between the inner circumferential surface of the mounting hole 22 and the outer circumferential surface of the valve body 224. On the other hand, the seal ring 33 is interposed between the upper surface (first surface) of the passage body 208 and the lower surface (second surface) of the large diameter portion 223 of the valve housing 226. By fastening the rotor unit 210 to the passage body 208, the seal ring 33 is appropriately compressed in the axial direction of the mounting hole 22, thereby exerting its sealing function.

[0074] That is, in this embodiment, although the directions in which the crushed margins are formed are different between the seal ring 31 and the seal ring 33, a double seal structure 230 is realized. The seal ring 31 regulates communication between the refrigerant passage 20 and the sealed space S1, and the seal ring 33 regulates communication between the sealed space S1 and the outside air (atmosphere). As in the first embodiment, the seal ring 31 is made of HNBR and the seal ring 33 is made of EPDM. Therefore, the same effects as in the first embodiment can be obtained.

[0075] [Third embodiment] Figure 6 is a cross-sectional view showing a piping structure according to a third embodiment, in which Figure 6(A) shows a piping joint structure, and Figure 6(B) shows a piping connection structure. In this embodiment, a double seal structure similar to that of the first embodiment is provided at the connection portion of the pipes that constitute the refrigerant circulation passage of the refrigeration cycle.

[0076] As shown in FIG. 6(A), pipe 310 is cylindrical and has refrigerant passage 320 through which a refrigerant flows. One end of pipe 310 is provided with joint 314 for connection to another pipe 312 (see FIG. 6(B)) that constitutes a refrigeration cycle. Pipe 312 functions as the "first pipe," and pipe 310 functions as the "second pipe." Joint 314 integrally has large-diameter portion 316 and small-diameter portion 318, and is shaped like a stepped cylinder whose outer diameter decreases toward the tip. Two-stage seal rings 331, 333 are fitted onto the outer circumferential surface of small-diameter portion 318.

[0077] 6(B), double seal structure 330 is realized by interposing seal ring 331 and seal ring 333 between the outer peripheral surface of small diameter portion 318 of pipe 310 and the inner peripheral surface of pipe 312. Seal ring 331 functions as a "first seal ring," and seal ring 333 functions as a "second seal ring."

[0078] Small diameter portion 318 of pipe 310 functions as an "insertion portion" that is attached so as to be inserted into one end of pipe 312 from the tip side. By assembling pipe 310 and pipe 312 in this manner, a refrigerant circulation passage of the refrigeration cycle is formed, and refrigerant passage 320 is formed inside the refrigeration cycle. Seal ring 331 is arranged closer to the tip of small diameter portion 318 than seal ring 333, that is, inside pipe 312. Seal ring 333 is arranged farther from the tip of small diameter portion 318 than seal ring 331, that is, closer to the open end of pipe 312. As a result, a sealed space S1 is formed between seal ring 331 and seal ring 333 in the gap between the inner circumferential surface of pipe 312 and the outer circumferential surface of pipe 310.

[0079] With this configuration, the seal ring 331 regulates communication between the refrigerant passage 320 and the sealed space S1, and the seal ring 333 regulates communication between the sealed space S1 and the outside air (atmosphere). In this embodiment, the seal ring 331 is made of HNBR and the seal ring 333 is made of EPDM, similar to the first embodiment. Therefore, the same effect as the first embodiment can be obtained with respect to the sealing performance of the piping structure.

[0080] [Fourth embodiment] Figure 7 is a cross-sectional view schematically illustrating a device according to embodiment 4. Figure 7(A) shows the assembled structure of the device, and Figures 7(B) and (C) show the method of assembling the device. In this embodiment, a double seal structure is provided between multiple parts that make up the device.

[0081] As shown in FIG. 7(A), device 401 is configured by connecting and abutting part 410 and part 412. Parts 410 and 412 may be block-shaped parts provided with internal passages for forming refrigerant passages. Alternatively, one or both of parts 410 and 412 may be devices such as control valves, and their bodies or housings may be connected. Parts 410 and 412 are connected via coupling part 413. This allows internal passage 414 and internal passage 416 to communicate with each other, forming refrigerant passage 420. Coupling part 413 is assembled to fit into parts 410 and 412, respectively, and connects parts 410 and 412.

[0082] Seal rings 431 and 433 are fitted to the outer peripheral surface of joint part 413 with a gap between them in the axial direction. In addition, seal ring 432 is interposed between parts 410 and 412 at the contact surface so as to surround joint part 413. Seal rings 431 and 433, together with seal ring 432, form double seal structures 430. Seal rings 431 and 433 are made of HNBR and function as "first seal rings." Seal ring 432 is made of EPDM and functions as "second seal ring."

[0083] In the process of assembling device 401, first, seal ring 432 and joint part 413 are assembled to part 410 (FIG. 7(B)). An annular seal accommodating portion 418 is provided on the side of part 410 so as to surround the periphery of internal passage 414. Seal ring 432 is assembled so as to fit into seal accommodating portion 418.

[0084] One end side (the side of the surface that abuts against the component 412) of the internal passage 414 in the component 410 is slightly enlarged in diameter to form a mounting hole 422. One axial side of the coupling component 413 is inserted into the mounting hole 422, and the coupling component 413 is assembled to the component 410 (FIGS. 7(B) and (C)). At this time, a seal ring 431 is interposed between the inner peripheral surface of the mounting hole 422 and the outer peripheral surface of the coupling component 413.

[0085] Meanwhile, one end side (the side of the abutment surface with the part 410) of the internal passage 416 in the part 412 is slightly enlarged in diameter to form a mounting hole 434. The opposite axial end of the coupling part 413 is inserted into the mounting hole 434, and the parts 410 and 412 are fastened together with bolts or the like (not shown) (FIGS. 7(C) and (A)). At this time, a seal ring 433 is interposed between the inner circumferential surface of the mounting hole 434 and the outer circumferential surface of the coupling part 413, and a seal ring 432 is interposed on the opposing surfaces (abutment surfaces) of the parts 410 and 412.

[0086] In this embodiment, the part 412 functions as a "first part," and an assembly 440 of the part 410 and the joint part 413 functions as a "second part" (see FIG. 7(C)). In the assembly 440, the part of the joint part 413 that is exposed from the part 410 functions as an "insertion part."

[0087] 7(A), a sealed space S1 is formed that is surrounded by the part 410, the part 412, and the joint part 413. The seal rings 431 and 433 regulate communication between the refrigerant passage 420 and the sealed space S1, and the seal ring 432 regulates communication between the sealed space S1 and the outside air (atmosphere). In this embodiment, the seal rings 431 and 433 located on the inside of the device 401 are made of HNBR, and the seal ring 432 located on the outside is made of EPDM, so that the same effects as in the first embodiment can be obtained.

[0088] In this embodiment, the configuration has been exemplified in which the coupling part 413 is assembled to the part 410 to form the assembly 440, and then the assembly 440 is attached to the part 412. In a modified example, conversely, the coupling part 413 may be assembled to the part 412 to form an assembly, and then the assembly may be attached to the part 410. In this case, the part 410 functions as the "first part," and the assembly of the part 412 and the coupling part 413 functions as the "second part."

[0089] Although the preferred embodiment of the present invention has been described above, it goes without saying that the present invention is not limited to this specific embodiment, and various modifications are possible within the scope of the technical concept of the present invention.

[0090] [Variations] In the above embodiment, the first seal ring (seal ring 31, 331) is made of HNBR. In a modified example, other rubbers having lower propane permeability than the second seal ring (seal ring 33, 333), such as nitrile rubber (NBR), urethane rubber (U), or fluororubber (FKM), may be used.

[0091] In the above embodiment, propane (R290) is used as the refrigerant, but carbon dioxide (R744) may also be used. Carbon dioxide, like propane, has a relatively small molecular weight and similar refrigerant permeability to propane. In this regard, by using EPDM for the second seal ring and a rubber with lower refrigerant permeability than the second seal ring for the first seal ring, the same effects as those of the above embodiment can be achieved.

[0092] In the first embodiment described above, an example was shown in which both of the two seal rings constituting the double seal structure 30 are interposed between the outer peripheral surface of the valve body 24 and the inner peripheral surface of the mounting hole 22. In the second embodiment, an example was shown in which one of the two seal rings constituting the double seal structure 230 is interposed between the outer peripheral surface of the valve body 24 and the inner peripheral surface of the mounting hole 22, and the other is interposed between the upper surface of the passage body 208 and the lower surface (lower surface of the large diameter portion 223) of the valve body 224. In a modified example, both of the two seal rings constituting the double seal structure may be interposed between the upper surface (first surface) of the passage body and the lower surface (second surface) of the valve body.

[0093] In the first and second embodiments, a motor-operated valve is exemplified as one of the devices applied to the vehicle refrigeration cycle. In a modified example, the double seal structure may be employed in sealing locations of an accumulator, receiver, or other device installed in the refrigeration cycle. The double seal structure may also be employed in sealing locations of devices such as a compressor, outdoor heat exchanger, expansion device, evaporator, and indoor heat exchanger.

[0094] In the third embodiment, an example was shown in which both of the two seal rings constituting the double seal structure 330 are interposed between the outer peripheral surface of the joint 314 (the insertion portion of the second pipe) and the inner peripheral surface of the pipe 312 (the first pipe). In a modified example, at least the second seal ring may be provided on the axially opposing surfaces of the first pipe and the second pipe (joint).

[0095] Specifically, a first flange protruding radially outward may be provided at one end of the first pipe, and a second flange protruding radially outward may be provided at the base end of the insertion section of the second pipe, with the first flange and the second flange facing each other in the axial direction and abutting against each other. A first seal ring may be interposed between the outer peripheral surface of the insertion section of the second pipe and the inner peripheral surface of the first pipe, and a second seal ring may be interposed between the first flange and the second flange. Alternatively, both the first seal ring and the second seal ring may be interposed between the first flange and the second flange.

[0096] In the first embodiment, the passage body 8 to which a single second component (valve unit 6) is attached is exemplified as the "first component." In a modified example, the first component may be a passage body (a housing member such as a block) having multiple mounting holes to which multiple second components (valve units) are attached. The first component may also be a housing for a device other than a control valve, such as a compressor or an evaporator.

[0097] In the third embodiment, the cylindrical pipe 312 is exemplified as the "first pipe." In a modified example, a pipe-shaped portion (piping portion) provided in a housing or the like of a device may be the "first pipe."

[0098] In the first embodiment, the valve unit 6 constituting the motor-driven electric valve 1 is exemplified as the "second component." The rotor 60 and the stator 62 function as the "drive unit." In a modified example, the second component may be a valve unit constituting a solenoid valve (a control valve with a solenoid as a drive unit). Alternatively, the second component may be a valve unit constituting a control valve (mechanical control valve) driven by fluid pressure or the like.

[0099] In the first embodiment, an example has been shown in which the valve unit 6 is formed and the motor-operated valve 1 is assembled by assembling each of the rotor unit 10 and the stator unit 12 to the passage body 8. In a modified example, the rotor unit and the stator unit may be pre-assembled to form a valve unit (motor-operated valve), which may then be assembled to a first component such as the passage body.

[0100] In the above embodiment, O-rings with a circular cross section are used as the seal rings that make up the double seal structure, but square rings with a polygonal cross section or other seal rings (gaskets) may also be used. Alternatively, each seal ring may be made by baking rubber onto the surface of a metal ring.

[0101] In the above embodiment, a double seal structure using two seal rings has been exemplified. In a modified example, a triple or more seal structure using three or more seal rings may be used. Even in this case, the multiple seal rings include a double seal structure using a second seal ring made of EPDM and a first seal ring made of rubber that is less permeable to propane and carbon dioxide than the second seal ring.

[0102] In the first embodiment, a configuration in which lubricating plating is applied to the guide member 102 is exemplified. In a modified example, the material of the guide member 102 may not be stainless steel like the first valve body 32, but may be a different material such as brass. This can prevent wear caused by the material.

[0103] In the first embodiment, the stator includes a yoke having pole teeth. In a modified example, the stator may include a laminated core.

[0104] In the first embodiment, the stator unit 12 is a two-phase stepping motor, but it may also be configured as a three-phase stepping motor.

[0105] In the first embodiment, an example was shown in which the small-diameter second valve functions as an expansion valve. In the second embodiment, an example was shown in which the small-diameter valve unit 204 functions as an expansion valve. In a modified example, these small-diameter valves may function as on-off valves without an expansion function.

[0106] The present invention is not limited to the above-described embodiments and modifications, and the components can be modified without departing from the spirit of the invention. Various inventions can be formed by appropriately combining multiple components disclosed in the above-described embodiments and modifications. Furthermore, some components can be omitted from all the components shown in the above-described embodiments and modifications. [Explanation of symbols]

[0107] 1 motor-operated valve, 2 first valve, 4 second valve, 6 valve unit, 8 passage body, 10 rotor unit, 12 stator unit, 20 refrigerant passage, 22 mounting hole, 23 female thread, 24 valve body, 25 male thread, 26 valve seat member, 28 seal ring, 30 double seal structure, 31 seal ring, 32 first valve body, 33 seal ring, 36 first valve seat, 38 valve hole, 40 second valve seat, 42 operating rod, 44 second valve body, 54 screw feed mechanism, 60 rotor, 62 stator, 78 case, 80 seal ring, 108 back pressure chamber, 110 valve chamber, 112 operating connecting member, 122 seal ring, 124 seal ring, 130 communicating hole, 201 motor-operated valve, 204 valve portion, 206 valve unit, 208 passage body, 210 Rotor unit, 224 valve body, 230 double seal structure, 240 valve chamber, 242 operating rod, 260 rotor, 262 rotating shaft, 310 piping, 312 piping, 314 joint, 320 refrigerant passage, 330 double seal structure, 331 seal ring, 333 seal ring, 401 device, 410 parts, 412 parts, 413 joint parts, 414 internal passage, 416 internal passage, 418 seal accommodating portion, 420 refrigerant passage, 422 mounting hole, 430 double seal structure, 431 seal ring, 432 seal ring, 433 seal ring, 434 mounting hole, 440 assembly, S1 sealed space.

Claims

1. A device applied to a vehicle refrigeration cycle using propane or carbon dioxide as a refrigerant, a first component having a refrigerant passage through which the refrigerant flows and an attachment hole communicating with the refrigerant passage; a second component having an insertion portion attached to be inserted into the mounting hole, the insertion portion being attached to the mounting hole to close the mounting hole; a double seal structure including a first seal ring and a second seal ring respectively interposed on opposing surfaces of the first component and the second component, forming a sealed space between the first seal ring and the second seal ring; Equipped with the first seal ring restricts communication between the refrigerant passage and the sealed space, the second seal ring regulates communication between the sealed space and the outside air, the second seal ring is made of ethylene propylene diene rubber (EPDM), The device, wherein the first seal ring is made of rubber that is less permeable to the refrigerant than the second seal ring.

2. a control valve for controlling the flow of refrigerant in the refrigeration cycle; a passage body as the first component; a valve unit as the second component; Equipped with The valve unit includes: a valve body that is inserted into the mounting hole and assembled to the passage body; a valve element that opens and closes a valve portion provided in the valve body; a drive unit for driving the valve body in the opening and closing direction of the valve unit; The device of claim 1 , comprising:

3. It is configured as an electric valve, the valve unit includes a rotor unit and a stator unit, The rotor unit includes: the valve body; The valve body; a rotor constituting the drive unit; a can, which is a cylindrical member fixed coaxially to the valve body and enclosing the rotor, and which defines an internal space on which fluid pressure acts and an external space on which fluid pressure does not act; Including, The stator unit includes: a stator that is coaxially inserted around the can and that constitutes the driving unit; a case containing the stator; 3. The device of claim 2, comprising:

4. A device as described in any one of claims 1 to 3, characterized in that the first seal ring and the second seal ring are each interposed between the inner surface of the mounting hole in the first part and the outer surface of the insertion portion in the second part.

5. the first part has a first surface facing the second part in the axial direction of the mounting hole, while the second part has a second surface facing the first part in the axial direction of the mounting hole, the first seal ring is interposed between an inner peripheral surface of the mounting hole in the first component and an outer peripheral surface of the insertion portion in the second component, 4. The device according to claim 1, wherein the second seal ring is interposed between the first surface of the first component and the second surface of the second component.

6. A piping structure applied to a vehicle refrigeration cycle using propane or carbon dioxide as a refrigerant, a first pipe having a refrigerant passage through which the refrigerant flows; a second pipe having an insertion portion attached so as to be inserted into one end of the first pipe, the second pipe constituting a refrigerant circulation passage of the refrigeration cycle together with the first pipe by attaching the insertion portion to the one end; a double seal structure including a first seal ring and a second seal ring respectively interposed on opposing surfaces of the first pipe and the second pipe, forming a sealed space between the first seal ring and the second seal ring; Equipped with the first seal ring restricts communication between the refrigerant passage and the sealed space, the second seal ring regulates communication between the sealed space and the outside air, the second seal ring is made of ethylene propylene diene rubber (EPDM), 10. A piping structure, wherein the first seal ring is made of rubber having a lower refrigerant permeability than the second seal ring.

7. The piping structure described in claim 6, characterized in that the first seal ring and the second seal ring are each fitted onto the outer peripheral surface of the insertion portion and interposed between the inner peripheral surface of the first piping and the outer peripheral surface of the insertion portion.

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