Check valve and refrigeration cycle system

Abstract

The present invention provides a check valve and a refrigeration cycle system, which can make the opening and closing movement of the valve core smooth. The check valve (1) includes an outer pipe portion (2), a valve body (3), and a valve core (4). The valve body (3) has a cylindrical valve holder (5) for supporting the valve core (4), a valve seat portion (6), and a valve port (7). The valve core (4) is configured to be axially movable within the valve holder (5) between a closed valve position where it seats on the valve seat portion (6) and an open valve position (P1) where it leaves the valve seat portion (6). A communication hole (21) is provided in the valve holder (5), and the communication hole (21) penetrates the cylindrical peripheral surface to communicate the inside of the outer pipe portion (2) with the valve port (7). The outer peripheral surface of the valve core (4) and the inner peripheral surface of the valve holder (5) are configured to slidably contact via a contact portion that contacts each other and a non-contact portion that does not contact each other and is separated.

Description

Technical Field

[0001] The present invention relates to a check valve and a refrigeration cycle system. Background Art

[0002] Conventionally, as a check valve, the following technique is known: a valve body provided inside an outer pipe and a valve element provided inside the valve body, the valve body having a valve seat portion constituting a valve port and a cylindrical valve holder (valve housing) that movably accommodates the valve element (for example, refer to Patent Document 1). In this check valve, a communication hole that communicates the inside of the outer pipe with the valve port is provided in the valve holder.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Utility Model Laid-Open No. 2006-200552 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] Here, the conventional check valve as described in Patent Document 1 is used in the middle of the refrigerant flow path in a refrigeration cycle system. Most of such refrigerants contain refrigeration oil for lubrication, but if there is refrigeration oil between the outer peripheral surface of the valve element and the inner peripheral surface of the valve holder, there may be a case where the moving resistance of the valve element is generated due to its surface tension. At this time, the larger the contact area between the outer peripheral surface of the valve element and the inner peripheral surface of the valve holder, the greater the moving resistance, and there is a possibility of hindering the opening and closing of the valve element.

[0008] An object of the present invention is to provide a check valve and a refrigeration cycle system that can smoothly open and close the valve element.

[0009] Means for Solving the Problems

[0010] The check valve of the present invention includes: a cylindrical outer pipe portion extending in the axial direction; a valve body disposed inside the outer pipe portion; and a valve element provided on the valve body. The check valve is characterized in that the valve body has: a cylindrical valve holder that supports the valve element; a valve seat portion on which the valve element can be seated; and a valve port that is closed by the valve element seated on the valve seat portion. The valve element is configured to be axially movable between a closed valve position where it is seated on the valve seat portion and an open valve position where it is away from the valve seat portion inside the valve holder. A communication hole is provided in the valve holder, and the communication hole penetrates the cylindrical circumferential surface to communicate the inside of the outer pipe portion with the valve port. The outer peripheral surface of the valve element and the inner peripheral surface of the valve holder are configured to perform sliding contact via a contact portion that is in contact with each other and a non-contact portion that is separated and not in contact with each other.

[0011] According to such an aspect of the present invention, a non-contact portion is provided between the outer peripheral surface of the valve element and the inner peripheral surface of the valve holder, thereby suppressing the contact area of the contact portion to be relatively small. As a result, even when there is refrigerating machine oil between the outer peripheral surface of the valve element and the inner peripheral surface of the valve holder, it is possible to reduce the moving resistance caused by the surface tension of the refrigerating machine oil, the outer peripheral surface of the valve element does not stick to the inner peripheral surface of the valve holder, and the opening / closing movement of the valve element can be made smooth.

[0012] At this time, it is preferable that the non-contact portion is constituted by a plurality of grooves formed in at least one of the outer peripheral surface of the valve element and the inner peripheral surface of the valve holder, and the plurality of grooves are provided at positions that are line-symmetrical with respect to the central axis of the valve element. According to this structure, the non-contact portion is effectively constituted by the plurality of grooves, and the plurality of grooves are provided at positions that are line-symmetrical with respect to the central axis of the valve element, so that the moving resistance is uniformly dispersed around the central axis, and thus the opening / closing movement of the valve element can be made further smooth. In addition, as the non-contact portion, by providing grooves in the valve element, the valve element becomes lighter, and the pressure difference required for opening the valve becomes smaller, so that the valve can also be easily opened.

[0013] Moreover, it is preferable that the plurality of grooves are formed to have equal sizes to each other. According to this structure, the weight distribution around the central axis in the valve element is made uniform, and thus the opening / closing movement of the valve element can be made more smooth.

[0014] In addition, it is preferable that the plurality of grooves are each formed to extend in the valve element axial direction along the central axis of the valve element, and the cross-sectional shape of a cross-section intersecting with the valve element axial direction is constant in the valve element axial direction or gradually changes in the valve element axial direction. According to this structure, the grooves constituting the non-contact portion extend in the valve element axial direction, so that the remaining contact portion also extends in the valve element axial direction, and the opening / closing movement of the valve element along the valve element axial direction can be made more smooth. In addition, the cross-sectional shape of the cross-section of the groove intersecting with the valve element axial direction is constant or gradually changes in the valve element axial direction, so that the weight distribution in the valve element axial direction in the valve element is made uniform or changes gently, and in this respect, the opening / closing movement of the valve element can also be made further smooth.

[0015] In addition, it is preferable that the non-contact portion is a groove formed in the outer peripheral surface of the valve element, and when the valve is fully opened with the valve element moved away from the valve seat portion to the fully open position, the groove communicates with the communication hole. According to this structure, the portion where the groove communicates with the communication hole functions as a discharge hole for the refrigerating machine oil existing in the contact portion, and it is possible to prevent the refrigerating machine oil from accumulating in the groove, and thus it is possible to suppress the retention of the surface tension of the refrigerating machine oil in the contact portion and make the opening / closing movement of the valve element more smooth.

[0016] In addition, it is preferable that a valve limiter is provided on the valve body. The valve limiter is fixed to the valve holder to limit the opening degree of the valve element. The opening-side end surface of the valve element and the valve seat-side end surface of the valve limiter are configured to approach and separate via an axially contacting portion that contacts each other and an axially non-contacting portion that does not contact and is separated from each other. Generally, in a structure where positioning during valve opening is performed by abutting against a valve limiter as described above, there is a possibility that refrigeration oil also enters between the opening-side end surface of the valve element and the valve seat-side end surface of the valve limiter. At this time, the following situation may occur: The refrigeration oil that enters between the opening-side end surface of the valve element and the valve seat-side end surface of the valve limiter adheres the two surfaces to each other due to surface tension, generating a moving resistance when the valve element at the valve opening position that abuts against the valve limiter attempts to move toward the valve closing position. Also, the following situation may occur: The larger the contact area between the opening-side end surface of the valve element and the valve seat-side end surface of the valve limiter, the greater the above-mentioned moving resistance. If the opening-side end surface of the valve element adheres to the valve seat-side end surface of the valve limiter, the valve will not close. In response to this, according to the above-preferred structure, the opening-side end surface of the valve element and the valve seat-side end surface of the valve limiter contact via the axially contacting portion and the axially non-contacting portion. Therefore, the contact area between the opening-side end surface and the valve seat-side end surface is suppressed to be small. As a result, even if there is refrigeration oil between the two surfaces, the moving resistance caused by the surface tension of the refrigeration oil can be reduced, the opening-side end surface of the valve element will not adhere to the valve seat-side end surface of the valve limiter, and the opening and closing movement of the valve element can be made smooth.

[0017] In addition, the valve limiter is preferably a C-shaped snap ring. According to this structure, for example, compared with the case where the valve seat-side end surface is a circular surface, the area of the valve seat-side end surface of the valve limiter is suppressed to be small. That is, the contact area between the opening-side end surface and the valve seat-side end surface is also suppressed to be small on the valve limiter side. Therefore, the adhesion between the opening-side end surface of the valve element and the valve seat-side end surface of the valve limiter can be further suppressed, and the opening and closing movement of the valve element can be made more smooth. In addition, according to the above structure, a cheap and easily installed C-shaped snap ring is used as the valve limiter, so the manufacturing cost can also be reduced.

[0018] It is preferable that a weight-reducing hole is formed in the valve element. The weight-reducing hole extends axially in the valve element to a predetermined depth and does not penetrate. According to this structure, it is possible to suppress the generation of dents, air bubbles, etc. when the valve element is formed of resin. In addition, by forming the weight-reducing hole, the valve element is lightened, so the opening pressure difference also becomes smaller, making it easier to open the valve, and the opening and closing movement of the valve element can also be made more smooth.

[0019] In addition, the refrigeration cycle system of the present invention is characterized by including the check valve described in any one of the above.

[0020] According to such a present invention, since the above check valve is adopted in the refrigeration cycle system, the opening and closing movement of the valve element in the check valve can be made smooth.

[0021] Effect of the Invention

[0022] According to the check valve and the refrigeration cycle system of the present invention, the opening and closing movement of the valve element can be made smooth. Description of the Drawings

[0023] Figure 1 It is an overall cross-sectional view showing an axial cross-section of a check valve according to an embodiment.

[0024] Figure 2 It is an enlarged view showing Figure 1 An enlarged cross-sectional view of the main part of the check valve shown.

[0025] Figure 3 It is Figure 1 and Figure 2 A top view of the valve element shown, a cross-sectional view along line V0-V1 in the figure, and a cross-sectional view along line V0-V2 in the figure.

[0026] Figure 4 It is Figures 1 to 3 A top view and a side view of the valve element shown.

[0027] Figure 5 It is a diagram showing Figures 1 to 4 A refrigeration cycle system according to an embodiment including the check valve shown.

[0028] In the figure:

[0029] 1 - Check valve, 2 - Outer tube part, 3 - Valve body, 4 - Valve element, 4A - Central axis, 4B - Contact part, 4C - Non-contact part, 4D - Discharge hole, 4E - Axial contact part, 4F - Axial non-contact part, 5 - Valve holder, 6 - Valve seat part, 7 - Valve port, 21 - Communication hole, 22 - Valve limiter, 22A - Valve seat side end face, 41 - Blade-shaped rib, 41A - Front edge, 41B - Cross-shaped end face (valve opening side end face), 43 - Groove, 50 - Refrigeration cycle system. Detailed Description of the Embodiment

[0030] Hereinafter, based on Figures 1 to 4 A check valve according to an embodiment of the present invention will be described.

[0031] Figure 1 It is an overall cross-sectional view showing an axial cross-section of a check valve according to an embodiment, Figure 2 It is an enlarged view showing Figure 1 An enlarged cross-sectional view of the main part of the check valve shown.

[0032] The details of the check valve 1 of the present embodiment are as described later. It is used in the middle of the refrigerant flow path in the refrigeration cycle system, and the refrigerant containing lubricating refrigeration oil flows as a fluid. AsFigure 1 As shown, the check valve 1 is a valve device that allows fluid to flow from the primary side ( Figure 1 the lower side) to the secondary side ( Figure 1 the upper side) (forward flow), and prohibits the flow of fluid from the secondary side to the primary side (reverse flow). The check valve 1 includes: a cylindrical outer pipe portion 2 extending in the axial direction along the axis L; a valve body 3 disposed inside the outer pipe portion 2; and a valve core 4 provided on the valve body 3. The valve body 3 is a component made of brass or the like integrally formed with a cylindrical valve holder 5 that supports the valve core 4 and a valve seat portion 6 on which the valve core 4 can be seated. A valve port 7 that is closed by the seated valve core 4 is formed in the valve seat portion 6. As Figure 2 shown, the valve core 4 is provided in the valve holder 5 so as to be axially movable between a closed valve position P2 where it is seated on the valve seat portion 6 and an open valve position P1 where it is separated from the valve seat portion 6.

[0033] The outer pipe portion 2 is a copper integrally formed component, and includes: a primary connection portion 11 on the primary side; a secondary connection portion 12 on the secondary side; a first enlarged diameter portion 13 having a diameter larger than that of the primary connection portion 11; and a second enlarged diameter portion 14 having a diameter larger than that of the first enlarged diameter portion 13 and continuous with the secondary connection portion 12. The primary connection portion 11 has: a primary opening portion 11A connected to a primary pipe (not shown); a cylindrical primary cylindrical portion 11B continuous with the primary opening portion 11A; and a first connection portion 11C that expands in diameter from the primary cylindrical portion 11B toward the first enlarged diameter portion 13. In addition, the secondary connection portion 12 has: a secondary opening portion 12A connected to a secondary pipe (not shown); a cylindrical secondary cylindrical portion 12B continuous with the secondary opening portion 12A; and a second connection portion 12C that expands in diameter from the secondary cylindrical portion 12B toward the second enlarged diameter portion 14. The diameter of the secondary opening portion 12A is slightly larger than that of the secondary cylindrical portion 12B.

[0034] The first enlarged diameter portion 13 is a portion that holds the valve seat portion 6 press-fitted into its interior, and fixing portions 13A that deform radially inward to fix the valve seat portion 6 are formed at four positions on the circumferential surface. These fixing portions 13A are riveted and deformed by a punch of a stamping device and bite into an annular recess 25 of the valve seat portion 6, whereby the valve seat portion 6 is fixed to a predetermined position inside the outer pipe portion 2. The second enlarged diameter portion 14 is formed in a cylindrical shape such that its inner circumferential surface faces the outer circumferential surface of the valve holder 5 with a predetermined gap therebetween and has an inner diameter dimension that allows fluid to flow smoothly through the gap. A stepped portion 14A that contracts in diameter toward the first enlarged diameter portion 13 is provided at the boundary portion between the second enlarged diameter portion 14 and the first enlarged diameter portion 13.

[0035] The valve frame 5 of the valve body 3 is provided with connecting holes 21 that penetrate the cylindrical peripheral surface in the radial direction at four locations. Through these connecting holes 21, the interior of the valve frame 5 is connected to the interior of the second expanded diameter portion 14 of the outer tube portion 2. The connecting holes 21 are formed in a circular shape when viewed from the side. That is, the connecting holes 21 are formed by drilling with respect to the valve frame 5 in a direction perpendicular to the axis using a drill or the like. A valve stopper 22 made of SUS and in a roughly annular shape is installed on the inner surface near the secondary side end of the valve frame 5. By moving to Figure 1 as well as Figure 2 The valve core 4 at the valve opening position P1 shown abuts against the valve stopper 22, thereby limiting the movement of the valve core 4 to the secondary side more than the valve opening position P1. Specifically, a C-type retaining ring is used as the valve stopper 22. That is, the valve opening position P1 is the position after the valve core 4 leaves the valve seat portion 6, and further, the valve core 4 abuts against the valve stopper 22, thereby limiting the position of the valve core 4 moving more to the secondary side than the valve stopper 22 (the maximum position in the secondary side direction in the valve stroke). Figure 2 In the figure, the upper stage shows the valve core 4 located at the valve opening position P1 in the valve frame 5.

[0036] The valve seat portion 6 has a cylindrical portion 23 extending toward the primary side, and a stepped valve seat surface 24 is provided on the inner surface of the secondary side (valve frame 5 side) end of the cylindrical portion 23. Figure 2 The valve core 4 at the closed valve position P2 shown in the lower section of the figure is seated on the valve seat surface 24. An annular recess 25 is formed on the outer surface near the primary end of the cylindrical portion 23, into which the fixing portion 13A of the outer tube portion 2 bites. In addition, an annular convex portion 26 protruding in the radial direction is formed on the outer surface of the secondary end of the valve seat portion 6, and the annular convex portion 26 abuts against the inner surface of the step portion 14A of the outer tube portion 2, so that the valve body 3 is positioned relative to the outer tube portion 2. When CO2 refrigerant is used at ultra-high pressure, the inner surface of the step portion 14A can bear the force applied to the valve seat portion 6 in the closing direction when the valve is closed, which has the effect of preventing the valve seat portion 6 from being pressed into and offset. A D-shaped cut portion 27 in which a part of the circumference is cut off is formed on the annular convex portion 26. Here, although the annular convex portion 26 of the valve seat portion 6 abuts against the inner surface of the step portion 14A of the outer tube portion 2, a liquid seal portion as a tiny gap is formed between them. The refrigerant as a fluid enters and accumulates in the liquid seal portion, and is rapidly exposed to high temperature in a state where the refrigerant is cooled and liquefied. In this case, the liquid refrigerant rapidly expands in volume, but is connected to the liquid seal portion through the D-shaped cut portion 27, so that the expanded refrigerant is led out to the inside of the outer tube portion 2. Therefore, it is possible to prevent the outer tube portion 2 and the valve seat portion 6 from being damaged or deformed due to the expansion pressure of the refrigerant.

[0037] Figure 3 yes Figure 1 as well as Figure 2The top view of the spool shown, the cross-sectional view along the line V0-V1 in the figure, and the cross-sectional view along the line V0-V2 in the figure. Additionally, Figure 4 is Figures 1 to 3 the top view of the spool shown, and the side view. Furthermore, the slanted portion in the top view of the spool 4 indicates the contact portion that contacts the valve limiter 22, and the slanted portion in the side view indicates the contact portion above the transverse hole 21 that contacts the inner peripheral surface of the valve holder 5.

[0038] As Figures 2 to 4 shown, the spool 4 is a resin component with four grooves 43 in the axial direction D11 of the spool on the outer peripheral surface of the cylinder, and the cross-sectional shape intersecting the axial direction D11 of the spool is formed in a substantially cross shape. Its outer diameter is set slightly smaller than the inner diameter of the valve holder 5, and it can move axially within the valve holder 5 along the inner peripheral surface of the valve holder 5. The spool 4 is formed with four grooves 43 on the outer peripheral surface of the cylinder in such a way that four leaf-shaped ribs 41 around the central axis 4A and the bottom plate portion 42 on the primary side that abuts against the valve seat surface 24 are retained.

[0039] The four grooves 43 are provided at positions that are line-symmetric with respect to the central axis 4A of the spool 4, specifically, at four positions arranged at 90° intervals around the central axis 4A. Additionally, the four grooves 43 are each formed to extend in the axial direction D11 of the spool along the central axis 4A of the spool 4. And in each groove 43, the cross-sectional shape of the cross-section intersecting the axial direction D11 of the spool becomes a fan shape with a central angle of approximately 90° and a constant cross-section constant portion 43A up to the middle of the secondary side in the axial direction D11 of the spool. Additionally, from the primary side end of the cross-section constant portion 43A to the bottom plate portion 42 in the groove 43 becomes a cross-section changing portion 43B, and the cross-sectional shape of this cross-section changing portion 43B gradually changes in the axial direction D11 of the spool in such a way that it depicts an arc with a central angle of approximately 90° and the groove depth becomes shallower. The four grooves 43 each have a cross-section constant portion 43A and a cross-section changing portion 43B and are formed in the same shape with equal sizes to each other.

[0040] The bottom plate portion 42 of the spool 4 has a flat conical shape that connects the bottom surfaces of the cross-section changing portions 43B in the grooves 43 in the circumferential direction. An umbrella-shaped recess 42A is formed on the primary side of this bottom plate portion 42, and in Figure 2 the closed valve position P2 shown, the periphery of this recess 42A is seated in contact with the valve seat surface 24. The spool 4 is seated in this way in the closed valve position P2, thereby closing the valve port 7 and preventing the reverse flow of fluid from the secondary side to the primary side.

[0041] In addition, when the valve is opened, the fluid flowing in the forward direction flows out from the valve port 7, and the recessed portion 42A of the bottom plate portion 42 effectively receives the fluid. The valve core 4 moves in a manner of lifting toward the secondary side to open the valve. The end portion on the secondary side (i.e., the valve-opening side end face) of the valve core 4 forms a cross-shaped end face 41B constituted by the end edges of the four blade-shaped ribs 41 on the secondary side. In Figure 2 the shown valve-opening position P1, the four end portions 41B-1 in the radially outer direction of the cross-shaped end face 41B, that is, the portions shown by oblique lines in the upper part of the figure in Figure 4 abut against the valve seat side end face 22A in the valve limiter 22 to limit the movement. At this time, the cross-shaped end face 41B (valve-opening side end face) of the valve core 4 and the valve seat side end face 22A of the valve limiter 22 approach and separate via the following axial contact portion 4E and axial non-contact portion 4F as the valve core 4 moves. The axial contact portion 4E is a portion of the valve core 4 constituted by the four end portions 41B-1 of the cross-shaped end face 41B. In addition, the axial non-contact portion 4F is a portion constituted by the end portions 43C on the valve-opening side of the four grooves 43 between the four end portions 41B-1.

[0042] In addition, in the present embodiment, a weight-reducing hole 44 is formed in the valve core 4. The weight-reducing hole 44 extends from the end face on the valve-opening position P1 side, that is, the central portion of the above-mentioned cross-shaped end face 41B, along the valve core axial direction D11 to a predetermined depth and does not penetrate. In addition, different from the weight-reducing hole 44 of the present embodiment, a non-penetrating weight-reducing hole may be provided that opens from the central portion of the recessed portion 42A of the bottom plate portion 42 along the valve core axial direction D11 in the opposite direction.

[0043] Here, the valve core 4 formed with four grooves 43 and retaining the four blade-shaped ribs 41 and the primary side bottom plate portion 42 constitutes a contact portion 4B where the front edge 41A of the four blade-shaped ribs 41 contacts the inner peripheral surface 5A of the valve holder 5. In addition, the four grooves 43 constitute a non-contact portion 4C that is separated from and does not contact the inner peripheral surface 5A of the valve holder 5. The valve core 4 is configured to be in sliding contact with the inner peripheral surface 5A of the valve holder 5 via the contact portion 4B and the non-contact portion 4C.

[0044] In addition, as shown in Figure 2 each of the four grooves 43 constituting the non-contact portion 4C is configured such that when the valve core 4 moves from the valve seat portion 6 to the fully opened valve position P1 where the valve is fully opened, the primary side end portions of the four grooves 43 communicate with the four communication holes 21 in the valve holder 5 respectively. As a result, at the valve-opening position P1, a passage is formed between the non-contact portion 4C (i.e., the four grooves 43) of the valve core 4 and the outer space of the valve holder 5. In the present embodiment, when there is refrigerating machine oil in the contact portion 4B, this passage functions as a discharge hole 4D for discharging the refrigerating machine oil.

[0045] When used in the vertical state shown in Figure 1 , referring to Figures 1 to 4The described check valve 1 operates as follows. First, when the valve element 4 is seated and in the closed valve position P2, if the fluid flows from the primary side to the secondary side in the forward flow, the valve element 4, which is pushed by the fluid flowing out from the valve port 7, moves to the open valve position P1 where it abuts against the valve limiter 22. If the forward flow stops, the valve element 4 drops due to its own weight and moves to the closed valve position P2 where it is seated on the valve seat portion 6.

[0046] In addition, the check valve 1 operates as follows when used in a horizontally placed state or a vertically placed state with the up and down directions reversed. Figure 1 First, in the closed valve position P2, it is set that the pressure on the secondary side is higher than that on the primary side. Due to the differential pressure at this time, the valve element 4 is pressed against the valve seat portion 6 and maintains the seated state. In this state, if the fluid flows from the primary side to the secondary side in the forward flow, the valve element 4, which is pushed by the fluid flowing out from the valve port 7, moves to the open valve position P1, which is the farthest from the valve seat and abuts against the valve limiter 22. Also, when closing the valve, by setting the pressure on the secondary side to be higher than that on the primary side, the valve element 4 moves to the closed valve position P2 where it is seated on the valve seat portion 6 due to this differential pressure.

[0047] As described below, this check valve 1 is used in the middle of the refrigerant flow path in a refrigeration cycle system.

[0048] Figure 5 It shows a refrigeration cycle system related to one embodiment including Figures 1 to 4 the shown check valve.

[0049] This Figure 5 shown refrigeration cycle system 50 uses, for example, an air conditioner such as a commercial air conditioner. This refrigeration cycle system 50 is formed by connecting an indoor heat exchanger 51, an outdoor heat exchanger 52, an expansion valve 53, a four-way valve 54, and three compressors 55 connected in parallel using pipes. To prevent the reverse flow of the refrigerant to each compressor 55, the check valve 1 is connected between the discharge (high-pressure output) side of each compressor 55 and the four-way valve 54 with the compressor 55 as the primary side and the four-way valve 54 as the secondary side.

[0050] During the refrigeration operation, as shown by the solid-line arrow D51, the refrigerant that has absorbed heat from the indoor heat exchanger 51 flows through the four-way valve 54 to the compressor 55. After being compressed by the compressor 55, it reaches the outdoor heat exchanger 52 via the check valve 1 and the four-way valve 54. Then, after releasing heat from the outdoor heat exchanger 52, it returns to the indoor heat exchanger 51 via the expansion valve 53. During the heating operation, as shown by the dotted-line arrow D52, the refrigerant that has released heat from the indoor heat exchanger 51 reaches the outdoor heat exchanger 52 via the expansion valve 53. After absorbing heat from the outdoor heat exchanger 52, it flows through the four-way valve 54 to the compressor 55. After being compressed by the compressor 55, it returns to the indoor heat exchanger 51 via the check valve 1 and the four-way valve 54. The refrigeration cycle system 50 repeats the above cycle to perform indoor refrigeration or heating.

[0051] Here, for example, under the condition of a large cooling load, since three compressors 55 are operating simultaneously, the check valves 1 of the three compressors are all in the fully open state. Additionally, under the condition of a small cooling load, since it is sufficient to operate only one compressor 55, the other two compressors 55 do not operate. At this time, the secondary-side pressure of the check valves 1 of the two compressors is higher than the primary-side pressure, resulting in a reverse flow from the secondary side, and the check valves 1 of the two compressors are in the closed state.

[0052] According to the check valve 1 and the refrigeration cycle system 50 of the embodiment described above, by providing a non-contact portion 4C between the outer peripheral surface of the valve core 4 and the inner peripheral surface 5A of the valve holder 5, the contact area in the contact portion 4B is suppressed to be relatively small. Thereby, even if there is refrigeration oil between the outer peripheral surface of the valve core 4 and the inner peripheral surface 5A of the valve holder 5, the moving resistance caused by the surface tension of the refrigeration oil can be reduced, the outer peripheral surface of the valve core 4 will not stick to the inner peripheral surface 5A of the valve holder 5, and the opening and closing movement of the valve core 4 can be made smooth.

[0053] Here, in the present embodiment, the non-contact portion 4C is composed of four grooves 43 formed on the outer peripheral surface of the valve core 4, and these four grooves 43 are arranged at positions that are line-symmetrical with respect to the central axis 4A of the valve core 4. According to this structure, the non-contact portion 4C is effectively composed of four grooves 43, and these four grooves 43 are arranged at positions that are line-symmetrical with respect to the central axis 4A of the valve core 4, so that the moving resistance is evenly dispersed around the central axis 4A, and thus the opening and closing movement of the valve core 4 can be made further smooth. Additionally, as the non-contact portion 4C, by providing the grooves 43 on the valve core 4, the valve core 4 becomes lighter, and the pressure difference required for opening the valve becomes smaller, so the valve can also be easily opened.

[0054] Moreover, in the present embodiment, the four grooves 43 are formed to be of equal size. According to this structure, the weight distribution of the valve core 4 around the central axis 4A is homogenized, and the opening and closing movement of the valve core 4 can be made more smooth.

[0055] Further, in the present embodiment, the four grooves 43 are each formed to extend in the valve element axial direction D11 along the central axis 4A of the valve element 4. Moreover, each groove 43 has a constant cross-section portion 43A where the cross-sectional shape of the cross-section intersecting the valve element axial direction D11 is constant in the valve element axial direction D11 and a gradually changing cross-section changing portion 43B. According to this structure, the grooves 43 constituting the non-contact portion 4C extend in the valve element axial direction D11, whereby the remaining contact portion 4B also extends in the valve element axial direction D11, enabling the opening and closing movement of the valve element 4 along the valve element axial direction D11 to be smoother. Further, the cross-sectional shape of the cross-section of the groove 43 intersecting the valve element axial direction D11 is constant or gradually changes in the valve element axial direction D11, so that the weight distribution in the valve element axial direction D11 in the valve element 4 is made uniform or changes smoothly. According to the above structure, the opening and closing movement of the valve element 4 can be further smoothed in this regard.

[0056] Further, in the present embodiment, when the valve element 4 is fully opened from the valve seat portion 6 to the fully open valve position P1, the groove 43 communicates with the communication hole 21 of the valve holder 5. According to this structure, the portion where the groove 43 communicates with the communication hole 21 functions as a discharge hole 4D for the refrigerating oil existing in the contact portion 4B, preventing the refrigerating oil from accumulating in the groove 43. Thereby, the retention of the surface tension of the refrigerating oil in the contact portion 4B is suppressed, and the outer peripheral surface of the valve element 4 does not stick to the inner peripheral surface 5A of the valve holder 5, enabling the opening and closing movement of the valve element 4 to be smoother.

[0057] Further, in the present embodiment, the cross-shaped end face 41B (fully open valve side end face) of the valve element is configured to approach and separate from the valve seat side end face 22A of the valve limiter 22 via the axial contact portion 4E and the axial non-contact portion 4F. Generally, in a structure in which the opening of the valve is positioned by abutting against the valve limiter 22 as described above, there is also a possibility that refrigerating oil enters between the cross-shaped end face 41B of the valve element 4 and the valve seat side end face 22A of the valve limiter 22. At this time, the refrigerating oil that has entered between the cross-shaped end face 41B of the valve element 4 and the valve seat side end face 22A of the valve limiter 22 acts to stick these two faces to each other due to surface tension. This action sometimes generates a moving resistance when the valve element 4 at the fully open valve position P1 that abuts against the valve limiter 22 moves away from the valve limiter 22 and attempts to move to the fully closed valve position P2.

[0058] Here, different from the present embodiment, consider the following structure: for example, the valve element is formed in a simple cylindrical shape, and the contact area between the fully open valve side end face of the valve element 4, which faces the valve limiter 22 through the circular face on the fully open valve side, and the valve seat side end face 22A of the valve limiter 22 becomes larger. In such a structure, there is also a case where the moving resistance caused by the sticking as described above becomes larger, and the fully open valve side end face of the cylindrical valve element sticks to the valve seat side end face 22A of the valve limiter 22 and does not separate, and the valve does not close.

[0059] In view of this, according to the present embodiment, since the cross-shaped end face 41B (valve-opening side end face) of the valve element 4 and the valve seat side end face 22A of the valve limiter 22 approach and separate via the axial contact portion 4E and the axial non-contact portion 4F, the contact area between the cross-shaped end face 41B and the valve seat side end face 22A is suppressed to be small. Thus, even if there is refrigerating machine oil between these two faces, the movement resistance caused by the surface tension of the refrigerating machine oil can be reduced, and the cross-shaped end face 41B of the valve element 4 will not stick to the valve seat side end face 22A of the valve limiter 22, and the opening and closing movement of the valve element 4 can be made smooth.

[0060] In addition, in the present embodiment, when the valve element 4 is in the valve-opening position P1, as described above, the groove 43 communicates with the communication hole 21 of the valve bracket 5 to form the discharge hole 4D. Therefore, the refrigerating machine oil between the cross-shaped end face 41B of the valve element 4 and the valve seat side end face 22A of the valve limiter 22 can also be discharged to the outside of the valve bracket 5 via the groove 43 and the discharge hole 4D, and in this respect, the opening and closing movement of the valve element 4 can also be made smooth.

[0061] In addition, in the present embodiment, as the valve limiter 22, a C-shaped retaining ring is adopted. According to this structure, different from the present embodiment, for example, compared with the case where the valve seat side end face is a circular face, the area of the valve seat side end face 22A of the valve limiter 22 is suppressed to be small. That is, the contact area between the cross-shaped end face 41B of the valve element 4 and the valve seat side end face 22A of the valve limiter 22 is also suppressed to be small on the valve limiter 22 side. As a result, the adhesion between the cross-shaped end face 41B of the valve element 4 and the valve seat side end face 22A of the valve limiter 22 can be further suppressed, and the opening and closing movement of the valve element 4 can be made more smooth. In addition, according to the above structure, the inexpensive and easily installed C-shaped retaining ring is used as the valve limiter 22, so the manufacturing cost can be reduced.

[0062] In addition, in the present embodiment, a weight-reducing hole 44 is formed in the valve element 4, and the weight-reducing hole 44 extends from the end face on the valve-opening position P1 side along the axial direction D11 of the valve element to a predetermined depth and does not penetrate. According to this structure, the generation of dents, air bubbles, etc. when the valve element 4 is formed of resin can be suppressed. In addition, by forming the weight-reducing hole 44, the valve element 4 is lightened, and thus the valve-opening pressure difference is also reduced, so the valve-opening is easy, and the opening and closing movement of the valve element 4 can also be made more smooth.

[0063] In addition, the above-described embodiments and modification examples are merely representative forms showing the present invention, and the present invention is not limited thereto. That is, various modifications can be made and implemented within the scope not departing from the gist of the present invention. As long as the check valve and the structure of the refrigeration cycle system of the present invention are also provided by this modification, it goes without saying that it is also included in the scope of the present invention.

[0064] For example, in the above-described embodiment, the check valve 1 used in an air conditioner for business use or the like is illustrated. However, the check valve is not limited to an air conditioner for business use, and can also be used in a home air conditioner. It is not limited to an air conditioner, and can also be applied to various refrigerators, freezers, etc. In addition, in the above various refrigeration cycle systems, it is not limited to being installed on the discharge side of the compressor as in the example of the installation of the check valve in the refrigeration cycle system 50 as shown in Figure 5 and can be used as a means for preventing backflow in various places in various refrigeration cycle systems. In addition, as the refrigerant for each refrigeration cycle system, there are various refrigerants (for example, various fluorocarbon refrigerants, hydrocarbon refrigerants, natural refrigerants such as CO2, ammonia, etc.). The check valve of the present invention can be applied to a refrigeration cycle system corresponding to any of the above refrigerants.

[0065] In addition, in the description of the above embodiment, regarding the communication holes 21, the structure provided at four positions penetrating the cylindrical peripheral surface of the valve holder 5 in the radial direction is described. However, it is not limited to four positions, and can also be one position, or two or more positions. In addition, it is described that the communication holes 21 are circular holes when viewed from the side, but it is not limited to being circular when viewed from the side, and can also be elliptical or the like. In addition, in the above embodiment, the check valve having a structure in which the outer pipe portion 2 (joint member and main body member) is an integrally formed member made of copper is described. However, the copper pipe joint members for the inlet and outlet and the main body member for accommodating the valve element can also be applied to a check valve having an independent structure.

[0066] In addition, in the above embodiment, as an example of the non-contact portion, the non-contact portion 4C constituted by four grooves 43 formed on the outer peripheral surface of the valve element 4 is illustrated. However, the non-contact portion is not limited to this, and can also be constituted by a plurality of grooves formed on the inner peripheral surface of the valve holder, or can also be constituted by a plurality of grooves formed on both the outer peripheral surface of the valve element and the inner peripheral surface of the valve holder. In addition, the non-contact portion is not limited to being constituted by such grooves. For example, it can also be a plurality of recessed portions formed on at least one of the outer peripheral surface of the valve element and the inner peripheral surface of the above valve holder. In addition, the groove can also be a spiral groove facing the axial direction.

[0067] In addition, in the above embodiment, as an example of the non-contact portion constituted by a plurality of grooves, the non-contact portion 4C constituted by four grooves 43 provided at positions that are line-symmetric with respect to the central axis 4A of the valve element 4 is illustrated. However, the non-contact portion is not limited to this, and the number and position of the grooves can be appropriately set. Therefore, the number of grooves can also be one or a plurality other than four. However, by constituting the non-contact portion 4C with four grooves 43 provided at positions that are line-symmetric with respect to the central axis 4A of the valve element 4, the opening and closing movement of the valve element 4 can be made smoother, as described above.

[0068] In addition, in the above-described embodiment, as an example of the plurality of grooves constituting the non-contact portion, four grooves 43 having the same size as each other are illustrated. However, the plurality of grooves constituting the non-contact portion is not limited to this, and they may have different sizes from each other. However, by configuring the non-contact portion 4C with four grooves 43 having the same size as each other, the opening and closing movement of the valve element 4 can be made smoother, as described above.

[0069] In addition, in the above-described embodiment, as an example of the groove constituting the non-contact portion, a groove 43 having both a cross-sectional constant portion 43A with a cross-sectional shape that intersects the valve element axial direction D11 and is constant in the valve element axial direction D11 and a cross-sectional varying portion 43B with a gradually changing cross-sectional shape is illustrated. However, the groove constituting the non-contact portion is not limited to this, and the cross-sectional shape of the groove can be set to any shape. However, by configuring the non-contact portion 4C with a groove 43 having a cross-sectional shape that is constant in the valve element axial direction D11 or a cross-sectional shape that gradually changes in the valve element axial direction D11, the opening and closing movement of the valve element 4 can be made smoother, as described above. In addition, the groove may be formed only by the cross-sectional constant portion with a cross-sectional shape that is constant in the valve element axial direction, or may be formed only by the cross-sectional varying portion with a cross-sectional shape that gradually changes in the valve element axial direction.

[0070] In addition, in the above-described embodiment, as an example of the non-contact portion constituted by grooves, a non-contact portion 4C constituted by grooves 43 that communicate with the communication hole 21 of the valve holder 5 when the valve is fully open is illustrated. However, the non-contact portion is not limited to this, and it may also be a non-contact portion where the communication portion is cut off from the communication hole when the valve is fully open. However, by configuring the non-contact portion 4C with grooves 43 that communicate with the communication hole 21 of the valve holder 5 when the valve is fully open, accumulation of refrigeration oil in the grooves 43 can be prevented, and thus the opening and closing movement of the valve element 4 can be made smoother, as described above.

[0071] In addition, in the above-described embodiment, as an example of the valve element, a valve element 4 is illustrated in which the opening-side end face is a cross-shaped end face 41B, and which approaches and separates from the valve seat-side end face 22A of the valve limiter 22 via the axial contact portion 4E and the axial non-contact portion 4F. However, the valve element is not limited to this. For example, it may also be a valve element in which the opening-side end face is a circular flat surface and which abuts against the valve limiter through this circular flat surface. However, according to the valve element 4 that approaches and separates from the valve seat-side end face 22A of the valve limiter 22 via the axial contact portion 4E and the axial non-contact portion 4F, the valve element 4 is likely to separate from the valve limiter 22, and the opening and closing movement of the valve element 4 can be made smoother, as described above. In addition, the opening-side end face is not limited to the above shape, and as long as the axial contact area is small, it may also be a shape other than a cross shape or a circular flat surface. In addition, the surface roughness of the axial contact portion may be made coarser to obtain the same effect.

[0072] In addition, in the above-described embodiment, as an example of the valve limiter, the valve limiter 22 of the C-ring was illustrated. However, as long as the valve limiter is fixed to the valve holder and limits the opening degree of the valve element, it may be, for example, a disc-shaped member or the like, regardless of its specific component form. However, by using the valve limiter 22 of the C-ring, the opening and closing movement of the valve element 4 can be made smoother, and in addition, the manufacturing cost can be reduced, as described above.

[0073] In addition, in the above-described embodiment, as an example of the valve element, the valve element 4 formed with the weight-reducing holes 44 was illustrated. However, the valve element is not limited to this, and it may be a valve element having a solid structure without the weight-reducing holes. However, by providing the weight-reducing holes 44 in the valve element 4, the generation of dents, bubbles, etc. during resin formation can be suppressed, and the opening and closing movement of the valve element 4 can be made smoother by weight reduction, as described above.

[0074] As described above, the embodiments of the present invention have been described in detail with reference to the drawings, but the specific structure is not limited to these embodiments, and design changes and the like within the scope not departing from the gist of the present invention are also included in the present invention.

Claims

1. A check valve, comprising: a cylindrical outer pipe portion extending along an axial direction; a valve body disposed inside the outer pipe portion; and a valve core disposed on the valve body, The check valve is characterized in that, The valve body has: a cylindrical valve holder that supports the valve core; a valve seat portion on which the valve core can be seated; and a valve port that is closed by the valve core seated on the valve seat portion, The valve core is configured to be axially movable within the valve holder between a closed valve position where it is seated on the valve seat portion and an open valve position where it is away from the valve seat portion, A communication hole is provided in the valve holder, and the communication hole penetrates the cylindrical circumferential surface to communicate the inside of the outer pipe portion with the valve port, The outer circumferential surface of the valve core and the inner circumferential surface of the valve holder are configured to perform sliding contact via a contact portion that is in contact with each other and a non-contact portion that is not in contact with each other and is separated, A bottom plate portion having a cylindrical outer circumferential surface is provided at an end portion of the valve core on the valve port side, At least in the closed valve position, the outer circumferential surface of the bottom plate portion and the entire circumference of the inner circumferential surface of the valve holder continuously form the contact portion.

2. The check valve according to claim 1, characterized in that, The non-contact portion is composed of a plurality of grooves formed on at least one of the outer circumferential surface of the valve core and the inner circumferential surface of the valve holder, and the plurality of grooves are provided at positions that are line-symmetric with respect to the central axis of the valve core.

3. The check valve according to claim 2, characterized in that, The plurality of grooves are formed to have equal sizes.

4. The check valve according to claim 2, characterized in that, The plurality of grooves are each formed to extend in the valve core axial direction along the central axis of the valve core, and the cross-sectional shape of a cross-section that intersects the valve core axial direction is constant in the valve core axial direction, or the cross-sectional shape gradually changes in the valve core axial direction.

5. The check valve according to claim 1, characterized in that, The non-contact portion is a groove formed on the outer circumferential surface of the valve core, and when the valve is fully open with the valve core moving away from the valve seat portion to the open valve position, the groove communicates with the communication hole.

6. The check valve according to claim 1, characterized in that, A valve limiter is provided on the valve body, and the valve limiter is fixed to the valve holder to limit the opening degree of the valve core, The end face on the open valve side of the valve core and the end face on the valve seat side of the valve limiter are configured to approach and separate via an axial contact portion that is in contact with each other and an axial non-contact portion that is not in contact with each other and is separated.

7. The check valve according to claim 6, characterized in that, The valve limiter is a C-shaped retaining ring.

8. The check valve according to claim 1, characterized in that, A weight-reducing hole is formed in the valve core, and the weight-reducing hole extends to a predetermined depth in the valve core axial direction and does not penetrate.

9. A freeze cycle system, characterized in that, It includes the check valve according to any one of claims 1 to 8.

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