Check valve and refrigeration cycle system

Abstract

To provide a check valve capable of smoothing the opening / closing movement of a valve body, and a refrigeration cycle system.SOLUTION: A check valve 1 comprises an outer pipe part 2, a valve body 3, and a valve element 4. The valve body 3 has a cylindrical valve holder 5 that supports the valve element 4, a valve seat part 6, and a valve port 7. The valve element 4 is provided in the valve holder 5 so as to be axially movable between a valve closed position where it is seated on the valve seat part 6 and a valve open position P1 away from the valve seat part 6. The valve holder 5 is provided with a communication hole 21 that penetrates a cylindrical peripheral surface and communicates the inside of the outer pipe part 2 with the valve port 7. The outer peripheral surface of the valve element 4 and the inner peripheral surface of the valve holder 5 are configured to be in slide contact via contact parts that are in contact with each other and non-contact parts that are separated without contact with each other.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] A conventional check valve is known that includes a valve body provided inside an outer tube and a valve element provided inside the valve body, the valve body having a valve seat portion that forms a valve port, and a cylindrical valve holder (valve case) that movably houses the valve element (see, for example, Patent Document 1). In this check valve, the valve holder is provided with a communication hole that communicates between the inside of the outer tube and the valve port. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-200552 A Summary of the Invention [Problem to be solved by the invention]

[0004] Here, a conventional check valve as described in Patent Document 1 is installed in the middle of a refrigerant flow path in a refrigeration cycle system. Many of these refrigerants contain refrigeration oil for lubrication, and if refrigeration oil is present between the outer circumferential surface of the valve body and the inner circumferential surface of the valve holder, the surface tension of the refrigeration oil may cause resistance to the movement of the valve body. In this case, the larger the contact area between the outer circumferential surface of the valve body and the inner circumferential surface of the valve holder, the larger the resistance to movement, which may cause problems in opening and closing the valve body.

[0005] An object of the present invention is to provide a check valve and a refrigeration cycle system that can smooth the opening and closing movement of a valve body. [Means for solving the problem]

[0006] The check valve of the present invention is a check valve comprising a cylindrical outer tube portion extending in the axial direction, a valve body built into the outer tube portion, and a valve element provided in the valve body, the valve body having a cylindrical valve holder supporting 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, and the valve element is movable in the axial direction within the valve holder between a valve closed position where it sits on the valve seat portion and a valve open position away from the valve seat portion. a valve body flat surface provided at a primary side end of the valve body abuts against the flat surface of the valve seat portion to close the valve, the valve holder is provided with a communication hole penetrating the cylindrical peripheral surface to communicate between the inside of the outer tube portion and the valve port, the outer peripheral surface of the valve body and the inner peripheral surface of the valve holder are configured to be in sliding contact with each other via a contact portion where they come into contact with each other and a non-contact portion where they are separated and do not come into contact with each other, and a bottom plate portion having the valve body flat surface is provided on the primary side of the valve body, At least when the valve is closed, The outer peripheral surface of the bottom plate The entire inner circumferential surface of the valve holder is continuous. The contact portion is characterized in that the contact portion is a contact portion.

[0007] According to the present invention, the contact area of ​​the contact portion is kept small by providing a non-contact portion between the outer peripheral surface of the valve disc and the inner peripheral surface of the valve holder, so that even if refrigeration oil is present between the outer peripheral surface of the valve disc and the inner peripheral surface of the valve holder, the movement resistance due to the surface tension of the refrigeration oil is reduced and the outer peripheral surface of the valve disc does not stick to the inner peripheral surface of the valve holder, thereby facilitating the opening and closing movement of the valve disc.

[0008] In this case, the non-contact portion is preferably formed of a plurality of grooves formed on at least one of the outer peripheral surface of the valve body and the inner peripheral surface of the valve holder, and the plurality of grooves are preferably provided at positions that are linearly symmetrical with respect to the central axis of the valve body. With this configuration, the non-contact portion is effectively formed by the plurality of grooves, and the plurality of grooves are provided at positions that are linearly symmetrical with respect to the central axis of the valve body, so that the movement resistance is uniformly distributed around the central axis, and therefore the opening and closing movement of the valve body can be made smoother. In addition, by providing grooves on the valve body as the non-contact portion, the valve body becomes lighter and the pressure difference required to open the valve is reduced, making it easier to open the valve.

[0009] Furthermore, it is preferable that the plurality of grooves are formed to be equal in size to each other. With this configuration, the weight distribution around the central axis of the valve body is made uniform, thereby making the opening and closing movement of the valve body even smoother.

[0010] In addition, it is preferable that each of the grooves is formed to extend in the valve body axial direction along the central axis of the valve body, and the cross-sectional shape of the cross section intersecting the valve body axial direction is constant in the valve body axial direction or the cross-sectional shape gradually changes in the valve body axial direction. With this configuration, the grooves constituting the non-contact portion extend in the valve body axial direction, so that the remaining contact portion also extends in the valve body axial direction, and the opening and closing movement of the valve body along the valve body axial direction can be further smoothed. In addition, since the cross-sectional shape of the grooves intersecting the valve body axial direction is constant or gradually changes in the valve body axial direction, the weight distribution in the valve body in the valve body axial direction is uniform or changes gradually, so that the opening and closing movement of the valve body can be further smoothed in this respect as well.

[0011] In addition, it is preferable that the non-contact portion is a groove formed on the outer peripheral surface of the valve body, and that the groove and the communication hole communicate with each other when the valve body is fully open and the valve body is separated from the valve seat to the valve open position. With this configuration, the portion where the groove and the communication hole communicate with each other functions as a relief hole for the refrigeration oil present in the contact portion, and the accumulation of the refrigeration oil in the groove is prevented, so that the retention of the surface tension of the refrigeration oil in the contact portion is suppressed, and the opening and closing movement of the valve body can be further smoothed.

[0012] In addition, the valve body is preferably provided with a valve stopper fixed to the valve holder to regulate the opening degree of the valve disc, and the valve opening side end face of the valve disc and the valve seat side end face of the valve stopper are configured to contact and separate via an axial contact portion where they contact each other and an axial non-contact portion where they are separated and do not contact each other. Generally, in a structure in which the valve is positioned when the valve is opened by abutting against the valve stopper as described above, refrigeration oil may also enter between the valve opening side end face of the valve disc and the valve seat side end face of the valve stopper. In this case, the refrigeration oil that has entered between the valve opening side end face of the valve disc and the valve seat side end face of the valve stopper may stick these two faces together due to surface tension, causing movement resistance when the valve disc in the valve open position abutting against the valve stopper tries to move to the valve closed position. The larger the contact area between the valve opening end face of the valve disc and the valve seat end face of the valve stopper, the larger the movement resistance, and if the valve opening end face of the valve disc remains stuck to the valve seat end face of the valve stopper, the valve may not close. In contrast, according to the above-mentioned preferred configuration, the valve opening end face of the valve disc and the valve seat end face of the valve stopper contact each other via the axial contact portion and the axial non-contact portion, so that the contact area between the valve opening end face and the valve seat end face is kept small. As a result, even if refrigeration oil is present between these two faces, the movement resistance due to the surface tension of the refrigeration oil is reduced, and the valve opening end face of the valve disc will not stick to the valve seat end face of the valve stopper, making it possible to smooth the opening and closing movement of the valve disc.

[0013] Moreover, the valve stopper is preferably a C-shaped retaining ring. With this configuration, the area of ​​the valve seat side end face of the valve stopper is kept small compared to, for example, a case where the valve seat side end face is a circular surface. In other words, the contact area between the valve opening side end face and the valve seat side end face is kept small even on the valve stopper side, so that sticking between the valve opening side end face of the valve body and the valve seat side end face of the valve stopper is further suppressed, and the opening and closing movement of the valve body can be further smoothed. Furthermore, with the above configuration, a C-shaped retaining ring, which is inexpensive and easy to install, is used as the valve stopper, so that the manufacturing cost can be reduced.

[0014] The valve body includes a valve body InsideIt is preferable that a non-through hole is formed extending to a predetermined depth in the axial direction of the valve body along the core axis. With this configuration, it is possible to suppress the occurrence of sink marks, air bubbles, etc. when forming the valve body from resin. In addition, since the valve body is lightened by forming the hole, the valve opening pressure difference is also reduced, making it easier to open the valve, and further facilitating the opening and closing movement of the valve body.

[0015] In addition, it is preferable that the valve body is formed of a resin material that does not contain reinforcing fibers. According to this configuration, since the valve body is formed of a resin material that does not contain reinforcing fibers and has a low elastic modulus and is easily deformed, even if the flatness of the sealing surface is low, the sealing surface can deform and come into close contact with the valve port, thereby suppressing valve leakage.

[0016] It is further preferable that the resin material is a PEEK material. According to this configuration, the valve body is formed of a PEEK material that has little plastic deformation and has excellent resistance to harsh operating environments such as high temperature and high pressure. By using such a PEEK material as the resin for forming the valve body, it is possible to obtain good shape recovery by suppressing plastic deformation after the back pressure is removed. In addition, it is possible to impart excellent resistance to the above-mentioned harsh operating environment to the valve body.

[0017] The refrigeration cycle system of the present invention is characterized by including any one of the check valves described above.

[0018] According to the present invention, the above-mentioned check valve is employed in a refrigeration cycle system, so that the opening and closing movement of the valve element in the check valve can be made smooth. Effect of the Invention

[0019] According to the check valve and the refrigeration cycle system of the present invention, the opening and closing movement of the valve body can be made smoother. [Brief description of the drawings]

[0020] [Figure 1]1 is an overall cross-sectional view showing a cross section along an axial direction of a check valve according to a first embodiment. [Diagram 2] 2 is an enlarged cross-sectional view showing a main part of the check valve shown in FIG. 1. [Diagram 3] 3A and 3B are a top view of the valve body shown in FIG. 1 and FIG. 2, a cross-sectional view taken along line V0-V1 in the figure, and a cross-sectional view taken along line V0-V2 in the figure. [Figure 4] 4A and 4B are a top view and a side view of the valve body shown in FIGS. 1 to 3. [Diagram 5] FIG. 5 is a diagram showing a refrigeration cycle system according to a first embodiment, which is provided with the check valve shown in FIGS. 1 to 4. [Figure 6] FIG. 6 is an overall cross-sectional view showing a cross section along an axial direction of a check valve according to a second embodiment. [Figure 7] 7A and 7B are a top view and a cross-sectional view of the valve body shown in FIG. 6 along line V14-V14 in the figure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, a check valve according to a first embodiment of the present invention will be described with reference to Figs. 1 to 4.

[0022] FIG. 1 is an overall cross-sectional view showing a cross section along an axial direction of a check valve according to a first embodiment, and FIG. 2 is an enlarged cross-sectional view showing a main part of the check valve shown in FIG. 1.

[0023] The check valve 1 of the first embodiment is used by being installed in the middle of a refrigerant flow path in a refrigeration cycle system, as described in detail later, and a refrigerant containing a lubricating refrigeration oil flows as a fluid. As shown in FIG. 1, the check valve 1 is a valve device that allows a fluid flow (forward flow) from the primary side (lower side in FIG. 1) to the secondary side (upper side in FIG. 1) and prohibits a fluid flow (backflow) from the secondary side to the primary side. The check valve 1 includes a cylindrical outer tube portion 2 extending in the axial direction along the axis L, a valve body 3 built in the outer tube portion 2, and a valve element 4 provided in the valve body 3. The valve body 3 is a member made of brass or the like, in which a cylindrical valve holder 5 that supports the valve element 4 and a valve seat portion 6 on which the valve element 4 can be seated are integrally formed, and the valve seat portion 6 is formed with a valve port 7 that is closed by the seated valve element 4. As shown in FIG. 2, the valve body 4 is disposed within the valve holder 5 so as to be freely movable in the axial direction between a valve closed position P2 in which the valve body 4 sits on the valve seat portion 6 and a valve open position P1 in which the valve body 4 is spaced apart from the valve seat portion 6.

[0024] The outer pipe portion 2 is an integrally molded member made of copper, and includes a primary joint portion 11 on the primary side, a secondary joint portion 12 on the secondary side, a first enlarged diameter portion 13 having a larger diameter than the primary joint portion 11, and a second enlarged diameter portion 14 having a larger diameter than the first enlarged diameter portion 13 and continuing to the secondary joint portion 12. The primary joint portion 11 has a primary opening portion 11A connected to a primary pipe (not shown), a cylindrical primary cylindrical portion 11B continuing to the primary opening portion 11A, and a first connecting portion 11C whose diameter is enlarged from the primary cylindrical portion 11B toward the first enlarged diameter portion 13. The secondary joint portion 12 has a secondary opening portion 12A connected to a secondary pipe (not shown), a cylindrical secondary cylindrical portion 12B continuing to the secondary opening portion 12A, and a second connecting portion 12C whose diameter is enlarged from the secondary cylindrical portion 12B toward the second enlarged diameter portion 14. The secondary opening portion 12A has a slightly larger diameter than the secondary cylindrical portion 12B.

[0025] The first enlarged diameter portion 13 is a portion that holds the valve seat portion 6 that is pressed into the inside thereof, and four fixing portions 13A that deform radially inward to fix the valve seat portion 6 are formed on the circumferential surface. These fixing portions 13A are crimped and deformed by a punch of a press machine, and bite into the annular recess 25 of the valve seat portion 6, so that the valve seat portion 6 is fixed at a predetermined position inside the outer tube portion 2. The second enlarged diameter portion 14 is formed in a cylindrical shape with an inner circumferential surface facing the outer circumferential surface of the valve holder 5 with a predetermined gap therebetween, and has an inner diameter dimension that allows the fluid to flow smoothly through the gap. At the boundary between the second enlarged diameter portion 14 and the first enlarged diameter portion 13, a step portion 14A that is reduced in diameter toward the first enlarged diameter portion 13 is provided.

[0026] The valve holder 5 of the valve body 3 has four communication holes 21 that penetrate the cylindrical peripheral surface in the radial direction, and these communication holes 21 communicate the inside of the valve holder 5 with the inside of the second enlarged diameter portion 14 of the outer tube portion 2. The communication holes 21 are circular in side view. That is, the communication holes 21 are formed by drilling a hole from a direction perpendicular to the axis of the valve holder 5. A valve stopper 22 made of SUS and having a substantially circular ring shape is attached to the inner surface near the secondary end of the valve holder 5. When the valve body 4 moves to the valve open position P1 shown in Figs. 1 and 2, it abuts against the valve stopper 22, thereby restricting the movement of the valve body 4 to the secondary side beyond the valve open position P1. Specifically, a C-shaped retaining ring is used as the valve stopper 22. That is, the valve open position P1 is a position where the valve disc 4 is separated from the valve seat 6 and where the valve disc 4 abuts against the valve stopper 22, restricting the movement of the valve disc 4 to the secondary side beyond the valve stopper 22 (the maximum position in the secondary side direction in the valve stroke). In Fig. 2, the valve disc 4 located at the valve open position P1 within the valve holder 5 is shown in the upper part of the drawing.

[0027] The valve seat 6 has a cylindrical portion 23 extending to the primary side, and a stepped valve seat surface 24 is provided on the inner surface of the secondary side (valve holder 5 side) end of the cylindrical portion 23, so that the valve body 4 that has moved to the valve closing position P2 shown in the lower part of FIG. 2 is seated on the valve seat surface 24. An annular recess 25 into which the fixing portion 13A of the outer tube portion 2 is engaged is formed on the outer surface of the primary side end of the cylindrical portion 23. In addition, an annular protrusion 26 protruding in the radial direction is formed on the outer surface of the secondary side end of the valve seat 6, and this annular protrusion 26 abuts against the inner surface of the stepped portion 14A of the outer tube portion 2, thereby positioning the valve body 3 relative to the outer tube portion 2. When used with ultra-high pressure such as CO2 refrigerant, the force that the valve seat 6 receives in the valve closing direction when the valve is closed can be received by the inner surface of the stepped portion 14A, which has the effect of preventing the valve seat 6 from being pressed out of position. The annular protrusion 26 is formed with a D-cut portion 27 in which a part of its circumferential direction is cut out. Here, the annular protrusion 26 of the valve seat 6 abuts against the inner surface of the step portion 14A of the outer tube portion 2, and a liquid seal portion, which is a minute gap, is formed between them. If the refrigerant, which is a fluid, enters and accumulates in this liquid seal portion and is suddenly exposed to high temperatures when it cools and liquefies, the liquid refrigerant will suddenly expand in volume, but since the D-cut portion 27 is connected to the liquid seal portion, the expanded refrigerant will escape into the outer tube portion 2. Therefore, damage and deformation of the outer tube portion 2 and the valve seat 6 due to the expansion pressure of the refrigerant can be prevented.

[0028] Fig. 3 is a top view of the valve disc shown in Fig. 1 and Fig. 2, a cross-sectional view along line V0-V1 in the figure, and a cross-sectional view along line V0-V2 in the figure. Fig. 4 is a top view and a side view of the valve disc shown in Fig. 1 to Fig. 3. The shaded area in the top view of the valve disc 4 indicates the contact portion with the valve stopper 22, and the shaded area in the side view indicates the contact portion with the inner peripheral surface of the valve holder 5 above the lateral hole 21.

[0029] 2 to 4, the valve body 4 is a resin member formed such that four grooves 43 are provided on the outer peripheral surface of a cylinder in the valve body axial direction D11, and the cross section intersecting the valve body axial direction D11 is substantially cross-shaped. The outer diameter of the valve body 4 is slightly smaller than the inner diameter of the valve holder 5, and the valve body 4 is provided along the inner peripheral surface of the valve holder 5 so as to be movable in the axial direction within the valve holder 5. The valve body 4 has the four grooves 43 formed on the outer peripheral surface of the cylinder so as to leave four feather-shaped ribs 41 around the central axis 4A and a bottom plate portion 42 on the primary side that abuts against the valve seat surface 24.

[0030] The four grooves 43 are provided at positions that are symmetrical with respect to the central axis 4A of the valve body 4, specifically, at four positions arranged at 90° intervals around the central axis 4A. The four grooves 43 are each formed to extend in the valve body axial direction D11 along the central axis 4A of the valve body 4. The cross-sectional shape of each groove 43 intersecting the valve body axial direction D11 is a constant cross-sectional portion 43A that is a sector shape with a central angle of approximately 90° up to the middle of the secondary side with respect to the valve body axial direction D11. The groove 43 is formed as a cross-sectional change portion 43B whose cross-sectional shape gradually changes in the valve body axial direction D11 so that the groove depth becomes shallow while drawing an arc with a central angle of approximately 90° from the primary side end of the constant cross-sectional portion 43A to the bottom plate portion 42. The four grooves 43 each have a constant cross-sectional portion 43A and a cross-sectional change portion 43B, and are formed to be equal in size and shape to each other.

[0031] The bottom plate portion 42 of the valve element 4 has a flattened conical shape formed by connecting the groove bottom surfaces of the cross-sectionally changing portions 43B of the groove 43 in the circumferential direction. An umbrella-shaped recess 42A is formed on the primary side of this bottom plate portion 42, and in the valve closed position P2 shown in Fig. 2, the peripheral edge of this recess 42A is seated so as to abut against the valve seat surface 24. The valve element 4 is seated in this manner in the valve closed position P2, thereby closing the valve port 7 and preventing backflow of fluid from the secondary side to the primary side.

[0032] When the valve is opened, the normal flow of fluid flows out of the valve port 7, and the recess 42A in the bottom plate portion 42 effectively receives the fluid, and the valve body 4 moves so as to be pushed up toward the secondary side, thereby opening the valve. The secondary side end of the valve body 4 (i.e., the valve opening side end face) is a cross-shaped end face 41B formed by the secondary side edges of the four feather-like ribs 41. At the valve opening position P1 shown in FIG. 2, the four radially outer ends 41B-1 of this cross-shaped end face 41B, i.e., the parts shown with diagonal lines in the upper drawing of FIG. 4, come into contact with the valve seat side end face 22A of the valve stopper 22, and the movement is restricted. At this time, the cross-shaped end face 41B (valve opening side end face) of the valve body 4 and the valve seat side end face 22A of the valve stopper 22 come into contact with and separate from each other via the axial contact portion 4E and the axial non-contact portion 4F as described below, as the valve body 4 moves. The axial contact portion 4E is a portion formed by the four ends 41B-1 of the cross-shaped end face 41B of the valve body 4. The axial non-contact portion 4F is a portion formed by the valve opening side ends 43C of the four grooves 43 between the four ends 41B-1.

[0033] In the present embodiment, the valve body 4 is formed with a non-through hole 44 that extends from the center of the end face on the valve open position P1 side, i.e., the cross-shaped end face 41B, to a predetermined depth in the valve body axial direction D11. Note that, unlike the hole 44 in the present embodiment, a non-through hole may be provided that opens in the valve body axial direction D11 from the center of the recess 42A in the bottom plate portion 42, which is in the opposite direction.

[0034] Here, in the valve body 4 in which the four grooves 43 are formed and the four feather-shaped ribs 41 and the primary side bottom plate portion 42 remain, the tip edges 41A of the four feather-shaped ribs 41 form contact portions 4B that come into contact with the inner circumferential surface 5A of the valve holder 5. In addition, the four grooves 43 form non-contact portions 4C that are separated from the inner circumferential surface 5A of the valve holder 5 without coming into contact with it. The valve body 4 is configured to come into sliding contact with the inner circumferential surface 5A of the valve holder 5 via the contact portions 4B and non-contact portions 4C.

[0035] 2, the four grooves 43 constituting the non-contact portion 4C are configured so that the primary side end of each of the four grooves 43 communicates with the four communication holes 21 in the valve holder 5 when the valve is fully open and the valve element 4 is separated from the valve seat portion 6 to the valve open position P1. As a result, at the valve open position P1, a passage is formed between the non-contact portion 4C of the valve element 4 (i.e., the four grooves 43) and the outer space of the valve holder 5. In this embodiment, this passage functions as a relief hole 4D for discharging refrigeration oil when the refrigeration oil is present in the contact portion 4B.

[0036] The check valve 1 described with reference to Figures 1 to 4 operates as follows when used in the vertically placed state shown in Figure 1. First, when the valve disc 4 is seated and in the valve closed position P2 and a fluid flows in the normal flow from the primary side to the secondary side, the valve disc 4 is pushed by the fluid flowing out of the valve port 7 and moves to the valve open position P1 where it abuts against the valve stopper 22. When the normal flow stops, the valve disc 4 falls under its own weight and moves to the valve closed position P2 where it sits on the valve seat portion 6.

[0037] When the check valve 1 is used in a horizontal position or in a vertical position that is upside down from that in Fig. 1, it operates as follows. First, in the valve closed position P2, the pressure on the secondary side is set higher than that on the primary side, and the valve element 4 is pressed against the valve seat 6 by the pressure difference at this time to maintain the seated state. When a fluid flows in a normal flow from the primary side to the secondary side in this state, the valve element 4 is pressed by the fluid flowing out of the valve port 7 and moves to the valve open position P1, which is the farthest from the valve seat that abuts against the valve stopper 22. Then, when the valve is closed, the pressure on the secondary side is made higher than that on the primary side, and the valve element 4 moves to the valve closed position P2 where it seats on the valve seat 6 by the pressure difference.

[0038] This check valve 1 is used by being installed midway along a refrigerant flow path in a refrigeration cycle system, as will be described below.

[0039] FIG. 5 is a diagram showing a refrigeration cycle system according to a first embodiment, which is provided with the check valve shown in FIGS.

[0040] 5 is used in an air conditioner such as a commercial air conditioner. The refrigeration cycle system 50 includes 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, all connected by piping. In order to prevent the refrigerant from flowing back into each compressor 55, a 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.

[0041] During cooling operation, as shown by solid arrow D51, the refrigerant that absorbs heat in the indoor heat exchanger 51 flows to the compressor 55 through the four-way valve 54, is compressed by the compressor 55, and then passes through the check valve 1 and the four-way valve 54 to the outdoor heat exchanger 52. Then, after discharging heat in the outdoor heat exchanger 52, the refrigerant returns to the indoor heat exchanger 51 through the expansion valve 53. During heating operation, as shown by dotted arrow D52, the refrigerant that discharges heat in the indoor heat exchanger 51 passes through the expansion valve 53 to the outdoor heat exchanger 52. Then, after absorbing heat in the outdoor heat exchanger 52, the refrigerant flows to the compressor 55 through the four-way valve 54, is compressed by the compressor 55, and then passes through the check valve 1 and the four-way valve 54 to return to the indoor heat exchanger 51. The refrigeration cycle system 50 repeats these cycles to cool or heat the room.

[0042] Here, for example, under conditions of high cooling load, the three compressors 55 are operated simultaneously, and each of the three check valves 1 is in a fully open state. On the other hand, under conditions of low cooling load, operation of only one compressor 55 is sufficient, and the other two compressors 55 are not operated. At this time, the secondary pressure of the two check valves 1 becomes higher than the primary pressure, causing a backflow from the secondary side, and the two check valves 1 are in a closed state.

[0043] According to the check valve 1 and refrigeration cycle system 50 of the first embodiment described above, the contact area at the contact portion 4B is kept small by providing the non-contact portion 4C between the outer circumferential surface of the valve body 4 and the inner circumferential surface 5A of the valve holder 5. As a result, even if refrigeration oil is present between the outer circumferential surface of the valve body 4 and the inner circumferential surface 5A of the valve holder 5, the movement resistance due to the surface tension of the refrigeration oil is reduced, and the outer circumferential surface of the valve body 4 does not stick to the inner circumferential surface 5A of the valve holder 5, making it possible to smooth the opening and closing movement of the valve body 4.

[0044] Here, in this embodiment, the non-contact portion 4C is configured by four grooves 43 formed on the outer peripheral surface of the valve body 4, and these four grooves 43 are provided at positions that are line-symmetrical with respect to the central axis 4A of the valve body 4. With this configuration, the non-contact portion 4C is effectively configured by the four grooves 43, and the four grooves 43 are provided at positions that are line-symmetrical with respect to the central axis 4A of the valve body 4, so that the movement resistance is uniformly distributed around the central axis 4A, which further facilitates the opening and closing movement of the valve body 4. Furthermore, by providing the grooves 43 in the valve body 4 as the non-contact portion 4C, the valve body 4 becomes lighter and the pressure difference required to open the valve becomes smaller, which makes it easier to open the valve.

[0045] Furthermore, in this embodiment, the four grooves 43 are formed to be equal in size to one another. With this configuration, the weight distribution around the central axis 4A of the valve body 4 is made uniform, so that the opening and closing movement of the valve body 4 can be made even smoother.

[0046] In this embodiment, the four grooves 43 are formed to extend in the valve body axial direction D11 along the central axis 4A of the valve body 4. Each groove 43 has a constant cross-sectional portion 43A whose cross-sectional shape intersecting the valve body axial direction D11 is constant in the valve body axial direction D11 and a gradually changing cross-sectional portion 43B whose cross-sectional shape gradually changes. With this configuration, the grooves 43 constituting the non-contact portion 4C extend in the valve body axial direction D11, so that the remaining contact portion 4B also extends in the valve body axial direction D11, and the opening and closing movement of the valve body 4 along the valve body axial direction D11 can be further smoothed. In addition, the cross-sectional shape of the grooves 43 intersecting the valve body axial direction D11 is constant or gradually changes in the valve body axial direction D11, so that the weight distribution in the valve body axial direction D11 in the valve body 4 is uniform or changes gradually. With the above configuration, the opening and closing movement of the valve body 4 can be further smoothed in this respect as well.

[0047] Furthermore, in this embodiment, when the valve is fully open and the valve element 4 is separated from the valve seat 6 to the valve open position P1, the groove 43 communicates with the communication hole 21 of the valve holder 5. With this configuration, the portion where the groove 43 communicates with the communication hole 21 functions as a relief hole 4D for the refrigeration oil present in the contact portion 4B, preventing the refrigeration oil from accumulating in the groove 43. This suppresses the retention of surface tension of the refrigeration oil in the contact portion 4B, and prevents the outer circumferential surface of the valve element 4 from sticking to the inner circumferential surface 5A of the valve holder 5, further facilitating the opening and closing movement of the valve element 4.

[0048] In this embodiment, the cross-shaped end face 41B (valve opening end face) and the valve seat side end face 22A of the valve stopper 22 are configured to come into contact with and separate from each other via the axial contact portion 4E and the axial non-contact portion 4F. In general, in a structure in which the valve is positioned when the valve is opened by abutting against the valve stopper 22 as described above, there is a possibility that refrigeration oil may also enter between the cross-shaped end face 41B of the valve body 4 and the valve seat side end face 22A of the valve stopper 22. At this time, the refrigeration oil that has entered between the cross-shaped end face 41B of the valve body 4 and the valve seat side end face 22A of the valve stopper 22 acts to stick these two faces together due to surface tension. Such an action may cause a movement resistance when the valve body 4 in the valve opening position P1 abutting against the valve stopper 22 tries to move away from the valve stopper 22 to the valve closing position P2.

[0049] Here, we consider a structure that is different from this embodiment and has a large contact area between the valve opening side end face of the valve disc 4 and the valve seat side end face 22A of the valve stopper 22, for example, where the valve disc is formed into a simple cylindrical shape and the circular surface on the valve opening side comes into contact with the valve stopper 22. In such a structure, the movement resistance due to the above-mentioned sticking increases, and there are cases where the valve opening side end face of the cylindrical valve disc sticks to the valve seat side end face 22A of the valve stopper 22 and cannot be released, preventing the valve from closing.

[0050] In contrast, according to this embodiment, the cross-shaped end face 41B (valve opening end face) of the valve body 4 and the valve seat side end face 22A of the valve stopper 22 come into contact with and separate from each other via the axial contact portion 4E and the axial non-contact portion 4F, thereby keeping the contact area between the cross-shaped end face 41B and the valve seat side end face 22A small. As a result, even if refrigeration oil is present between these two faces, the movement resistance due to the surface tension of the refrigeration oil is reduced, and the cross-shaped end face 41B of the valve body 4 does not stick to the valve seat side end face 22A of the valve stopper 22, making it possible to smooth the opening and closing movement of the valve body 4.

[0051] Furthermore, in this embodiment, when the valve element 4 is in the valve open position P1, the groove 43 communicates with the communication hole 21 of the valve holder 5 to form the relief hole 4D as described above. Therefore, refrigeration oil between the cross-shaped end face 41B of the valve element 4 and the valve seat side end face 22A of the valve stopper 22 can also be released to the outside of the valve holder 5 via the groove 43 and the relief hole 4D, and in this respect as well, the opening and closing movement of the valve element 4 can be made smoother.

[0052] In addition, in this embodiment, a C-shaped retaining ring is used as the valve stopper 22. According to this configuration, the area of ​​the valve seat side end face 22A of the valve stopper 22 is kept small compared to the case where the valve seat side end face is a circular surface, unlike the present embodiment. In other words, the contact area between the cross-shaped end face 41B of the valve body 4 and the valve seat side end face 22A of the valve stopper 22 is also kept small on the valve stopper 22 side. As a result, the sticking between the cross-shaped end face 41B of the valve body 4 and the valve seat side end face 22A of the valve stopper 22 is further suppressed, and the opening and closing movement of the valve body 4 can be further smoothed. In addition, according to the above configuration, a C-shaped retaining ring, which is inexpensive and easy to install, is used as the valve stopper 22, so that the manufacturing cost can be reduced.

[0053] In this embodiment, the valve body 4 is formed with a non-through hole 44 that extends from the end face on the valve open position P1 side to a predetermined depth in the valve body axial direction D11. This configuration makes it possible to prevent the occurrence of sink marks, air bubbles, etc. when forming the valve body 4 from resin. Furthermore, the formation of the hole 44 reduces the weight of the valve body 4, which in turn reduces the valve opening pressure difference, making it easier to open the valve and further facilitating the opening and closing movement of the valve body 4.

[0054] Next, a second embodiment will be described. In this second embodiment, the shape of the valve body of the check valve is different from that of the first embodiment. In the following, the check valve according to the second embodiment will be described with reference to Figs. 6 and 7, focusing on the differences from the first embodiment. On the other hand, the refrigeration cycle system is the same as that of the first embodiment, so illustrations and descriptions thereof will be omitted.

[0055] Fig. 6 is an overall cross-sectional view showing a cross section along the axial direction of the check valve according to the second embodiment, and Fig. 7 is a top view of the valve body shown in Fig. 6 and a cross-sectional view along the V14-V14 line in the figure. In Fig. 6, components equivalent to those of the check valve 1 of the first embodiment shown in Fig. 1 are given the same reference numerals as in Fig. 1, and hereinafter, redundant explanations of those equivalent components will be omitted.

[0056] The check valve 100 of the second embodiment is a valve device similar to the check valve 1 of the first embodiment, in which a valve body 3 is built into an outer tube portion 2 along an axis L, and a valve element 140 is provided in the valve body 3 while being supported by a cylindrical valve holder 5. The valve element 140 is provided so as to be movable in the axial direction between a valve closed position P2 where it seats on a valve seat portion 6 to close the valve port 7, and a valve open position P1 where it is spaced apart from the valve seat portion 6.

[0057] In this embodiment, the tip edges 141A of the four feather-like ribs 141 in the valve body 140 constitute the contact portion 140B, and the four grooves 143 constitute the non-contact portion 140C, which is the same as in the first embodiment described above. Also in this embodiment, the cross-shaped end face 141B (valve opening side end face) and the valve seat side end face 22A of the valve stopper 22 are configured to come into contact with and separate from each other via the axial contact portion 140E and the axial non-contact portion 140F. The axial contact portion 140E is configured by the four ends 141B-1 of the cross-shaped end face 141B, and the axial non-contact portion 140F is configured by the valve opening side ends 143C of the four grooves 143. On the other hand, in each groove 143, unlike the first embodiment, a cross-sectional change portion 143B is formed by rising obliquely from the bottom plate portion 142 without passing through a flat end portion. Also, the inclination is steeper than the cross-sectional change portion 43B of the first embodiment shown in FIG. 3. As a result, in this embodiment, the constant cross section portion 143A on the cross-shaped end face 141B side of the groove 143 has a length in the valve body axial direction D141 along the central axis 140A that is shorter than that of the constant cross section portion 43A of the first embodiment. Furthermore, in this embodiment, as shown in the cross-sectional view of Figure 7, the lightening hole 144 is a tapered hole with a round bottom that tapers in the valve body axial direction D141. Also, in the cross-shaped end face 141B, one ejector pin hole 141C is provided in each end face portion of the four feather-like ribs 141 to hold the valve body 140 when the valve body 140 is attached or detached.

[0058] In this embodiment, the valve body 140 is formed of a resin material that does not contain reinforcing fibers. Examples of this resin material include high-strength materials such as PEEK (polyether ether ketone), PI (polyimide), and PPS (polyphenylene sulfide). These high-strength materials are resin materials that are less prone to plastic deformation and have excellent resistance to harsh environments such as high temperature and high pressure. In this embodiment, among these high-strength materials, the particularly high-strength PEEK material is used. The valve body 140 is formed using PEEK material without containing reinforcing fibers such as CF (carbon fiber) and GF (glass fiber), and thus the valve body 140 has a wide elastic deformation range and is easily deformed (easily stretched) within the elastic range due to its low elastic modulus while having little plastic deformation and high resistance. In the above-mentioned first embodiment, the valve body 4 is merely described as a resin member, but the valve body 4 may also be formed of PEEK material that does not contain reinforcing fibers, as in the second embodiment.

[0059] It goes without saying that the second embodiment described above can also facilitate smooth opening and closing movement of the valve body 140, similar to the first embodiment described above.

[0060] In this embodiment, the valve body 140 is formed of a resin material that does not contain reinforcing fibers. According to this configuration, as described above, the valve body 140 is formed of a resin material that does not contain reinforcing fibers and has a low elastic modulus and is easily deformed. Here, in the valve body 140 that operates under the above-mentioned severe usage environment, the flatness of the sealing surface may be reduced. In the valve body 140, it is desirable that valve leakage during back pressure is suppressed even in such a case. At this time, according to this embodiment, since the valve body 140 is given the property of having a low elastic modulus and being easily deformed, even if the flatness of the sealing surface is low, the sealing surface deforms and comes into close contact with the valve port 7, thereby suppressing valve leakage.

[0061] In this embodiment, PEEK material, which has little plastic deformation and excellent resistance to harsh operating environments such as high temperature and high pressure, is used as the resin material forming the valve body 140. With this configuration, it is possible to achieve effects such as good shape recovery after the back pressure is removed and excellent resistance to the operating environment for the valve body 140, which has a low elastic modulus and is easily deformed as described above.

[0062] The first and second embodiments described above are merely representative forms of the present invention, and the present invention is not limited thereto. In other words, the present invention can be embodied in various modifications without departing from the gist of the present invention. As long as the check valve and refrigeration cycle system of the present invention are still provided, such modifications are of course included in the scope of the present invention.

[0063] For example, in the above-mentioned first and second embodiments, the check valve 1,100 used in an air conditioner such as a commercial air conditioner is exemplified, but the check valve may be used not only in a commercial air conditioner but also in a home air conditioner, and not only in an air conditioner but also in various freezers, refrigerators, etc. In addition, in the above-mentioned various refrigeration cycle systems, the check valve is not limited to being attached to the discharge side of the compressor as in the refrigeration cycle system 50 of FIG. 5, but can be applied to prevent backflow at various locations in various refrigeration cycle systems. In addition, there are a wide variety of refrigerants (for example, various fluorocarbon-based refrigerants, hydrocarbon-based refrigerants, natural refrigerants such as CO2 and ammonia, etc.) as refrigerants for each refrigeration cycle system. The check valve of the present invention can be applied to any of these refrigerants.

[0064] In the above description of the first and second embodiments, the communication holes 21 are provided at four locations that penetrate the cylindrical circumferential surface of the valve holder 5 in the radial direction, but the number of locations is not limited to four, and the communication holes 21 may be provided at one location or at two or more locations. In addition, the communication holes 21 are described as holes that are formed in a circular shape in side view, but the communication holes 21 are not limited to a circular shape in side view, and may be elliptical or the like. In addition, in the above description of the first and second embodiments, the check valve is described as having an outer tube portion 2 (joint member and main body member) that is an integrally formed member made of copper, but the present invention can also be applied to a check valve having a structure in which the copper pipe joint members at the inlet and outlet and the main body member that houses the valve body are separate.

[0065] In the above-described first and second embodiments, the non-contact portion 4C, 140C constituted by four grooves 43, 143 formed on the outer peripheral surface of the valve body 4, 140 is exemplified as an example of the non-contact portion. However, the non-contact portion is not limited to this, and may be constituted by a plurality of grooves formed on the inner peripheral surface of the valve holder, or may be constituted by a plurality of grooves formed on both the outer peripheral surface of the valve body and the inner peripheral surface of the valve holder. The non-contact portion is not limited to being constituted by such grooves, and may be, for example, a plurality of recesses formed on at least one of the outer peripheral surface of the valve body and the inner peripheral surface of the valve holder. The groove may be a spiral groove oriented in the axial direction.

[0066] In the above-described first and second embodiments, as an example of a non-contact portion composed of a plurality of grooves, the non-contact portion 4C, 140C composed of four grooves 43, 143 arranged at positions that are line-symmetrical with respect to the central axis 4A, 140A of the valve body 4, 140 is exemplified. However, the non-contact portion is not limited to this, and the number and positions of the grooves can be set appropriately. Therefore, the number of grooves may be a number other than one or four. However, as described above, by forming the non-contact portion 4C, 140C with four grooves 43, 143 arranged at positions that are line-symmetrical with respect to the central axis 4A, 140A of the valve body 4, 140, the opening and closing movement of the valve body 4, 140 can be further smoothened.

[0067] In the first and second embodiments described above, four grooves 43, 143 formed to be equal in size are illustrated as an example of the plurality of grooves constituting the non-contact portion. However, the plurality of grooves constituting the non-contact portion is not limited to this, and may be formed to be different in size. However, as described above, by forming the non-contact portion 4C, 140C with four grooves 43, 143 formed to be equal in size, the opening and closing movement of the valve body 4, 140 can be further smoothed.

[0068] In the above-mentioned first and second embodiments, the groove 43, 143 is exemplified as an example of the groove constituting the non-contact portion, in which the cross-sectional shape of the cross section intersecting the valve body axial direction D11, D141 has both a constant cross-sectional portion 43A, 143A and a gradually changing cross-sectional portion 43B, 143B. 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, as described above, the opening and closing movement of the valve body 4, 140 can be further smoothed by forming the non-contact portion 4C, 140C with the groove 43, 143 whose cross-sectional shape is constant in the valve body axial direction D11, D141 or whose cross-sectional shape gradually changes in the valve body axial direction D11, D141. The groove may be formed only with a constant cross-sectional portion whose cross-sectional shape is constant in the valve body axial direction, or may be formed only with a cross-sectional changing portion whose cross-sectional shape gradually changes in the valve body axial direction.

[0069] In the first and second embodiments described above, the non-contact parts 4C, 140C formed of the grooves 43, 143 that communicate with the communication hole 21 of the valve holder 5 when the valve is fully open are exemplified as an example of a non-contact part formed of a groove. However, the non-contact part is not limited to this, and the communication part may be blocked from the communication hole when the valve is fully open. However, as described above, by forming the non-contact parts 4C, 140C with the grooves 43, 143 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, 143 can be prevented, and the opening and closing movement of the valve body 4, 140 can be further smoothed.

[0070] In the first and second embodiments described above, the valve body 4, 140 is exemplified as an example of the valve body, in which the valve opening end face is a cross-shaped end face 41B, 141B and the valve seat side end face 22A of the valve stopper 22 is brought into contact with and separated from the valve seat side end face 22A of the valve stopper 22 via the axial contact portion 4E, 140E and the axial non-contact portion 4F, 140F. However, the valve body is not limited to this, and may be, for example, a valve opening end face that is a circular plane and abuts against the valve stopper at the circular plane. However, according to the valve body 4, 140 that is brought into contact with and separated from the valve seat side end face 22A of the valve stopper 22 via the axial contact portion 4E, 140E and the axial non-contact portion 4F, 140F, the valve body 4, 140 is easily separated from the valve stopper 22, and the opening and closing movement of the valve body 4, 140 can be smoothed, as described above. Furthermore, the shape of the valve opening end face is not limited to the above-mentioned shape, and as long as the axial contact area is small, it may be a cross shape or a shape other than a circular flat surface, and the surface roughness of the axial contact portion may be made rough, with the same effect being obtained.

[0071] In the above-mentioned first and second embodiments, the valve stopper 22 of a C-shaped retaining ring is exemplified as an example of the valve stopper. However, the valve stopper may be, for example, a disk-shaped member, etc., as long as it is fixed to the valve holder and regulates the opening degree of the valve body, and the specific member form is not important. However, as described above, by using the valve stopper 22 of a C-shaped retaining ring, the opening and closing movement of the valve body 4, 140 can be made smoother, and the manufacturing cost can also be reduced.

[0072] In the above-described first and second embodiments, the valve body 4, 140 having the lightening holes 44, 144 formed therein is exemplified as an example of the valve body. However, the valve body is not limited to this, and may be a solid structure without the lightening holes formed therein. However, by providing the lightening holes 44, 144 in the valve body 4, 140, the occurrence of sink marks, air bubbles, etc. during resin molding can be suppressed, and the opening and closing movement of the valve body 4, 140 can be further smoothened by the weight reduction, as described above.

[0073] In the above-described second embodiment, the valve body 140 formed of a resin material containing no reinforcing fibers is illustrated as an example of the valve body. However, the valve body is not limited to this, and may be formed of a resin material containing reinforcing fibers or other materials. However, as described above, by forming the valve body 140 from a resin material containing no reinforcing fibers, valve leakage during back pressure can be suppressed.

[0074] In the above-mentioned second embodiment, a PEEK material containing no reinforcing fibers is exemplified as an example of a resin material containing no reinforcing fibers forming the valve body. However, the resin material containing no reinforcing fibers forming the valve body is not limited to this, and other resins such as the above-mentioned PI material, PPS material, or PA (polyamide) material may be used as long as they do not contain reinforcing fibers. However, as described above, the use of a PEEK material containing no reinforcing fibers can provide particularly excellent effects in terms of shape recovery after the back pressure is eliminated and resistance to the usage environment.

[0075] Although the embodiments of the present invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention also includes design changes and the like that do not deviate from the gist of the present invention. [Explanation of symbols]

[0076] 1,100 Check valve 2 Outer tube part 3 Valve body 4,140 Valve body 4A,140A center axis 4B,140B Contact part 4C,140C Non-contact part 4D Relief hole 4E,140E Axial contact part 4F,140F Axial non-contact part 5 Valve holder 6 Valve seat 7. Valve Orifice 21 Communication hole 22 Valve stopper 22A Valve seat side end surface 41,141 Pinnate ribs 41A,141A Tip edge 41B, 141B Cross-shaped end face (valve opening side end face) 43,143 grooves 50 Refrigeration cycle system

Claims

1. A check valve comprising a cylindrical outer tube portion extending in an axial direction, a valve body contained in the outer tube portion, and a valve element provided in the valve body, The valve body includes 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 body is provided in the valve holder so as to be movable in the axial direction between a valve closed position in which the valve body is seated on the valve seat portion and a valve open position in which the valve body is spaced from the valve seat portion, The valve is closed by a flat surface of the valve body provided at the primary end of the valve body coming into contact with the flat surface of the valve seat portion, The valve holder is provided with a communication hole penetrating a cylindrical peripheral surface thereof to communicate the inside of the outer tube portion with the valve port, an outer circumferential surface of the valve body and an inner circumferential surface of the valve holder are configured to be in sliding contact with each other via a contact portion where the outer circumferential surface of the valve body and an inner circumferential surface of the valve holder are in sliding contact with each other and a non-contact portion where the outer circumferential surface of the valve body and the inner circumferential surface of the valve holder are spaced apart from each other without contacting each other, A check valve characterized in that there is a bottom plate portion having the flat surface of the valve body on the primary side of the valve body, and at least when the valve is closed, the entire circumference of the outer circumferential surface of the bottom plate portion and the inner circumferential surface of the valve holder form the contact portion without interruption.

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 peripheral surface of the valve body and the inner peripheral surface of the valve holder, and the plurality of grooves are provided at positions that are linearly symmetrical with respect to a central axis of the valve body.

3. 3. The check valve according to claim 2, wherein the plurality of grooves are formed to be equal in size to one another.

4. The check valve according to claim 2 or 3, characterized in that each of the plurality of grooves is formed to extend in a valve body axial direction along the central axis of the valve body, and a cross-sectional shape of a cross section intersecting the valve body axial direction is constant in the valve body axial direction, or the cross-sectional shape gradually changes in the valve body axial direction.

5. 5. The check valve according to claim 1, wherein the non-contact portion is a groove formed in an outer peripheral surface of the valve body, and the groove and the communication hole communicate with each other when the valve body is fully open and away from the valve seat to the valve open position.

6. A check valve as described in any one of claims 1 to 5, characterized in that the valve body is provided with a valve stopper fixed to the valve holder to regulate the opening degree of the valve body, and the valve opening side end face of the valve body and the valve seat side end face of the valve stopper are configured to come into contact with and separate from each other via an axial contact portion in which they come into contact with each other and an axial non-contact portion in which they are separated from each other without coming into contact with each other.

7. 7. The check valve according to claim 6, wherein the valve stopper is a C-shaped retaining ring.

8. The check valve according to any one of claims 1 to 7, characterized in that the valve body is formed with a non-through hole extending to a predetermined depth in the valve body axial direction along the central axis of the valve body.

9. 9. The check valve according to claim 1, wherein the valve body is made of a resin material that does not contain reinforcing fibers.

10. 10. The check valve according to claim 9, wherein the resin material is a PEEK material.

11. A refrigeration cycle system comprising the check valve according to any one of claims 1 to 10.

Images