Manufacturing method of three-way pipe unit, three-way pipe unit, and check valve bridge refrigerant circuit module

Abstract

To promote space saving by simplifying piping in a refrigerant cycle system.SOLUTION: In a method for manufacturing a three-way pipe unit 11 having a three-way pipe 12 having a main pipe part 13 having a first opening A1 at one end, and a second opening A2 at the other end, and a branch part 14 branched from an intermediate part 13a of the main pipe, and a first check valve V1 and a second check valve V2 which are arranged at both sides of the intermediate part so that forward directions C1, C2 become the same directions, the method includes: (1) a center-side diameter-contracted part forming process for forming a first diameter-contracted part and a second diameter-contracted part 15a which are formed by confining a peripheral wall of the main pipe part; after that, (2) a check valve installation process for inserting the first check valve from a first opening, and making it abut on the first diameter-contracted part, and inserting the second check valve from a second opening, and making it abut on the second diameter-contracted part; and (3) an end-part side diameter-contracted part forming process for forming a third diameter-contracted part 16 for preventing a positional displacement of the first check valve to the first opening side, and forming a fourth diameter-contracted part 16a for preventing a positional displacement of the second check valve to the second opening side.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a manufacturing method of a three-way pipe unit, a three-way pipe unit, and a check valve bridge refrigerant circuit module, and more particularly to a refrigerant piping unit equipped with a plurality of check valves that can be used in heating and cooling systems such as air conditioners. [Background technology]

[0002] Refrigeration and freezing equipment and air conditioners that utilize the refrigeration cycle are widely used today. For example, heat pump air conditioning systems that can perform both heating and cooling are used in air conditioners for transportation equipment such as car air conditioners, room air conditioners for homes and stores, and central air conditioning equipment for large buildings.

[0003] Further, the following patent documents disclose inventions relating to check valves and refrigerant circuits used in such refrigeration cycles. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-44418 A (Patent No. 5774943 A) [Patent Document 2] JP 2001-304442 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, such a heating and cooling air conditioning system is equipped with many valve devices such as four-way valves and check valves to switch the refrigerant flow paths, and the piping that connects these is complicated and intricate. This causes a problem in that it is difficult to secure working space when connecting the piping to build a system, or when maintenance or repair is required, and therefore simplification of the refrigerant piping and space saving are desired.

[0006] However, it is not always easy to reduce the space required for refrigerant piping (reducing the size). For example, a bridge refrigerant circuit using a check valve is sometimes used in a heat pump type heating and cooling air conditioning system, but if a bridge circuit is constructed using the check valve device according to the invention described in Patent Document 1, the resulting piping unit will be relatively long (see symbol L) as shown in Figure 37.

[0007] To save space in this piping unit, it is conceivable to first shorten the inlet port 2f and outlet port 2g of each check valve device 1 (the small diameter portions 2b, 2c and the tapered portions 2d, 2e on both sides of the valve assembly 7) in order to shorten the length L1 of each check valve device 1. However, these portions cannot be shortened easily. This is because the valve body 3, valve seat member 5, and seal member 6 included in the valve assembly 7 are made of resin or rubber, and it is necessary to prevent these members from being deformed by the heat of welding when connecting piping to each port 2f, 2g, so each port 2f, 2g needs to have a certain distance (length).

[0008] Furthermore, if the valve assembly 7 can be made smaller (shorter in size or smaller in diameter), it will be possible to shorten the large diameter portion 2a and thereby shorten the length L1 of the check valve device 1. However, in order to shorten the size of the valve assembly 7, it is necessary to also shorten the length (length in the operating direction) of the valve element 3 that slides in the axial direction along the guide member 4, which makes the valve element 3 more likely to tilt, which may cause malfunction. Furthermore, reducing the diameter of the valve assembly 7 is undesirable because it leads to a reduction in the cross-sectional area of ​​the refrigerant flow path (refrigerant flow rate).

[0009] On the other hand, the invention described in Patent Document 2 has the objective of saving space, and forms a bridge circuit by combining two bridge side components F, each of which has a pair of check valve elements E, E pressed into a straight pipe P sandwiching an intermediate piping M of a three-way pipe T (see Figures 7 to 9 in the same document).

[0010] However, high dimensional accuracy is required to fix a check valve into a pipe by pressing it in, and if there is variation (manufacturing error) in the outer diameter of the check valve element M and the inner diameter of the straight pipe P, it may become difficult to press in the check valve element M, or conversely, a gap may occur between the outer surface of the check valve element M and the inner surface of the straight pipe P, resulting in valve leakage.

[0011] Furthermore, when the three-way pipe T is formed by bulging or burring, which are suitable for mass production, the inner peripheral surface of the straight pipe P is likely to become rough near the intermediate pipe M. For this reason, when a check valve element M is disposed near the intermediate pipe M as described in Patent Document 2 (see Figures 8 and 9 in the same document), a gap is likely to occur between the outer peripheral surface of the check valve element and the inner peripheral surface of the straight pipe, making valve leakage more likely to occur.

[0012] On the other hand, if the inner peripheral surface of the straight pipe P is polished after the intermediate piping M is formed in order to prevent valve leakage, this will result in an increase in the number of manufacturing steps.

[0013] Therefore, an object of the present invention is to provide a new refrigerant piping unit, in particular a three-way pipe unit equipped with a check valve and a bridge refrigerant circuit module, which can simplify the piping within a refrigeration cycle system and achieve space saving. [Means for solving the problem]

[0014] In order to solve the above problems and achieve the object, all of the manufacturing methods for the three-way pipe unit according to the present invention (first to fourth inventions) integrate the three-way pipe and the check valve by fixing the check valve inside the three-way pipe, and the three-way pipe units according to the present invention (fifth to eighth inventions described later) also have similar characteristics. Each invention will be described below.

[0015] [First Invention] The manufacturing method of a three-way pipe unit according to a first invention of the present application is a method for manufacturing a three-way pipe unit including a three-way pipe having a main pipe section having a first opening at one end and a second opening at the other end and a branch section branching from an intermediate section of the main pipe section and having a third opening, a first check valve disposed between the first opening and the intermediate section such that the direction from the first opening toward the intermediate section is the forward direction, and a second check valve disposed between the intermediate section and the second opening such that the direction from the intermediate section toward the second opening is the forward direction. Note that the above-mentioned "forward direction" refers to a direction that allows the passage of a refrigerant, and the passage of a refrigerant in a direction opposite to the forward direction is prevented.

[0016] The manufacturing method includes: (1) a step of preparing the above-mentioned three-way pipe; (2) a central side reduced diameter portion forming step of constricting a peripheral wall of a main pipe portion of the prepared three-way pipe to form a first reduced diameter portion that regulates positional displacement of the first check valve toward the intermediate portion side, and constricting a peripheral wall of the main pipe portion to form a second reduced diameter portion that regulates positional displacement of the second check valve toward the intermediate portion side; and (3) after the central side reduced diameter portion forming step, fitting the first check valve into the main pipe portion from one end side (inserting it so as to fit it in) to form the first reduced diameter portion. and (4) an end-side reduced diameter portion forming step of constricting the peripheral wall of the main pipe to form a third reduced diameter portion that regulates misalignment of the first check valve towards the one end, and a fourth reduced diameter portion that regulates misalignment of the second check valve towards the other end, by constricting the peripheral wall of the main pipe to form a fourth reduced diameter portion that regulates misalignment of the second check valve towards the other end.

[0017] In the manufacturing method according to the first invention, a pair of reduced diameter portions are formed before and after the check valve (the portion where the check valve is located) (the end side close to the first opening or the second opening and the center side close to the intermediate portion), and each check valve (the first check valve and the second check valve) is fixed so as to be sandwiched within the main pipe by this pair of reduced diameter portions. The reduced diameter portions may be formed, for example, by constricting the pipe wall of the main pipe by press working as described later in the embodiment (the same applies to the second and subsequent inventions described later).

[0018] The check valves (first check valve and second check valve) can be, for example, the valve assembly included in the check valve device described in Patent Document 1. This valve assembly includes a cylindrical guide member having a bent portion where one end is bent inward, a valve body that is housed in the guide member and has a valve opening limit regulated by the bent portion (the limit position of the movement of the valve body in the valve opening direction is defined), and a valve seat member that is attached to the other end of the guide member and has a valve seat that moves in contact with and away from the valve body.

[0019] Moreover, the check valve preferably includes a seal member that seals between the outer circumferential surface of the check valve and the inner circumferential surface of the main pipe (the same applies to the second and subsequent inventions described below). For example, when using the valve assembly, the valve assembly may be provided with a groove formed in the outer circumferential surface of the valve seat member, and the groove may be provided with a seal member that seals between the inner circumferential surface of the main pipe and the outer circumferential surface of the valve seat member. The seal member may be, for example, an O-ring made of rubber or resin.

[0020] Furthermore, in one aspect of the first invention, either one or both of the first check valve and the second check valve may include a resin or rubber component, and the method may include a tubular member joining step of brazing or welding the tubular member to the third opening of the branching section. In this case, the tubular member joining step is preferably performed between the three-way pipe preparing step and the check valve installing step. This is to prevent the resin or rubber member included in the check valve from being deformed or altered due to heat generated when joining the tubular members, resulting in deterioration of the characteristics. Also, by performing the tubular member joining step before installing the check valve in this way, it is possible to place the check valve closer to the branching section, and the three-way pipe unit can be made smaller (shorter in size).

[0021] [Second Invention] The manufacturing method of a three-way pipe unit according to the second invention of the present application is, like the first invention, a method for manufacturing a three-way pipe unit including a three-way pipe having a main pipe section having a first opening at one end and a second opening at the other end and a branch section branching off from an intermediate section of the main pipe section and having a third opening, a first check valve arranged between the first opening and the intermediate section such that the direction from the first opening toward the intermediate section is the forward direction, and a second check valve arranged between the intermediate section and the second opening such that the direction from the intermediate section toward the second opening is the forward direction, and includes the following steps (1) to (6).

[0022] That is, the manufacturing method includes the steps of: (1) preparing a short three-way pipe having a short pipe section having a first connection port at one end and a second connection port at the other end, the branched section being branched off from an intermediate section of the short pipe section; (2) preparing a first extension pipe having a first small diameter end portion at one end, the first small diameter end portion having an outer diameter reduced so that the short pipe section can be inserted into the first connection port and an inner diameter reduced so that the first check valve can be abutted against the first small diameter end portion; (3) preparing a second extension pipe having a second small diameter end portion at one end, the second small diameter end portion having an outer diameter reduced so that the short pipe section can be inserted into the second connection port and an inner diameter reduced so that the second check valve can be abutted against the second small diameter end portion; and (4) connecting the first extension pipe and the second extension pipe to the short three-way pipe by inserting the first small diameter end portion into the first connection port and the second small diameter end portion into the second connection port, and connecting the other end of the first extension pipe to the first small diameter end portion. the other end of the second extension pipe being the second opening, and a three-way pipe is formed by the short three-way pipe, the first extension pipe, and the second extension pipe; (5) after the three-way pipe forming step, a check valve installation step of inserting the first check valve into the first extension pipe from the first opening at the other end of the first extension pipe so as to abut against the first small diameter end, thereby positioning the first check valve, and inserting the second check valve into the second extension pipe from the second opening at the other end of the second extension pipe so as to abut against the second small diameter end, thereby positioning the second check valve; and (6) a reduced diameter portion forming step of constricting a peripheral wall of the first extension pipe to form a first reduced diameter portion that restricts displacement of the first check valve towards the other end, and constricting a peripheral wall of the second extension pipe to form a second reduced diameter portion that restricts displacement of the second check valve towards the other end.

[0023] In the first invention, the check valve is sandwiched by forming a pair of reduced diameter parts in front and behind the check valve, but in this second invention and the third and fourth inventions described below, the support structure for the center side (side closer to the middle part) of each check valve is different. Note that the support structure for the end side (side closer to the first opening or second opening) is the same as in the first invention, and is performed by reduced diameter parts.

[0024] Specifically, in the second invention, the three-way pipe is composed of a short three-way pipe and extension pipes (first extension pipe and second extension pipe) connected to both ends of the short three-way pipe. Each extension pipe has a small diameter end portion with a small outer diameter so that it can be inserted into and connected to the end portion of the short three-way pipe and a small inner diameter so that the check valve can be abutted against it, and the central end portion of the check valve is abutted against this small diameter end portion to support the central end portion of the check valve.

[0025] [Modification of the second aspect of the invention] Furthermore, as a variation of the second invention, the connection structure of the short three-way pipe and the extension pipe may be reversed, that is, the small diameter end portion may be provided on the short three-way pipe side rather than on the extension pipe side. In this manner, the central end portion of the check valve can be supported by the small diameter end portion (the small diameter end portion provided on the short three-way pipe side), just like in the second invention.

[0026] More specifically, the manufacturing method of the three-way pipe unit according to the modified example is a method of manufacturing a three-way pipe unit having a three-way pipe including a main pipe portion having a first opening at one end and a second opening at the other end, and a branch portion branching off from an intermediate portion of the main pipe portion and having a third opening, a first check valve disposed between the first opening and the intermediate portion such that the direction from the first opening toward the intermediate portion is the forward direction, and a second check valve disposed between the intermediate portion and the second opening such that the direction from the intermediate portion toward the second opening is the forward direction, the method comprising the steps of: (1) preparing a short three-way pipe including a short pipe portion having a first small diameter end portion having a reduced outer diameter at one end and a second small diameter end portion having a reduced outer diameter at the other end, the branch portion branching off from an intermediate portion of the short pipe portion; (2) preparing a first extension pipe capable of being connected to the short pipe portion by inserting the first small diameter end portion; and (3) preparing a second check valve. Small diameter end (4) a three-way pipe forming step of connecting the first extension pipe and the second extension pipe to a short three-way pipe by fitting and inserting the first small diameter end portion into one end of the first extension pipe and the second small diameter end portion into one end of the second extension pipe, making the other end of the first extension pipe the first opening and the other end of the second extension pipe the second opening, thereby forming the three-way pipe with the short three-way pipe, the first extension pipe, and the second extension pipe; and (5) after the three-way pipe forming step, inserting a first check valve into the first extension pipe from the first opening at the other end of the first extension pipe. The method includes a check valve installation process for positioning the first check valve by inserting the first check valve into the pipe and abutting it against the first small diameter end of the short three-way pipe, and for positioning the second check valve by inserting the second check valve into the second extension pipe from a second opening at the other end of the second extension pipe and abutting it against the second small diameter end of the short three-way pipe; and (6) a reduced diameter portion forming process for constricting a peripheral wall of the first extension pipe to form a first reduced diameter portion that regulates misalignment of the first check valve toward the other end, and for constricting a peripheral wall of the second extension pipe to form a second reduced diameter portion that regulates misalignment of the second check valve toward the other end.

[0027] In the second invention and its modified examples, either one or both of the first check valve and the second check valve may include a resin or rubber component, and a tubular member joining step may be included in which a tubular member is brazed or welded to the third opening of the branch portion, as in the first invention. In this case, for the same reason as in the first invention, it is preferable to carry out the tubular member joining step between the three-way pipe forming step and the check valve installing step.

[0028] [Third Invention] The manufacturing method of a three-way pipe unit according to the third invention of the present application is a method for manufacturing a three-way pipe unit including a main pipe portion having a first opening at one end and a second opening at the other end, a branch portion branching from an intermediate portion of the main pipe portion and having a third opening, a first check valve disposed between the first opening and the intermediate portion so that the direction from the first opening toward the intermediate portion is the forward direction, and a second check valve disposed between the intermediate portion and the second opening so that the direction from the intermediate portion toward the second opening is the forward direction, similar to the first and second inventions, but the center side of the check valve is supported by a spacer pipe inserted into the main pipe portion and disposed in the intermediate portion of the main pipe portion. Specifically, the method includes the following steps (1) to (5).

[0029] That is, the manufacturing method includes: (1) a step of preparing the three-way pipe; (2) a step of preparing a spacer pipe having openings at both ends and having a peripheral opening on its peripheral surface that can communicate with the branch portion, and that can be fitted and inserted into the main pipe portion; (3) a spacer pipe arranging step of arranging the spacer pipe in an intermediate portion of the main pipe portion; (4) after the spacer pipe arranging step, a check valve installation step of inserting a first check valve into the main pipe portion from one end side of the main pipe portion so as to abut against the spacer pipe, thereby positioning the first check valve, and inserting a second check valve into the main pipe portion from the other end side of the main pipe portion so as to abut against the spacer pipe, thereby positioning the second check valve; and (5) a reduced diameter portion forming step of constricting the peripheral wall of the main pipe portion to form a first reduced diameter portion that restricts misalignment of the first check valve toward the one end side, and constricting the peripheral wall of the main pipe portion to form a second reduced diameter portion that restricts misalignment of the second check valve toward the other end side.

[0030] In the third invention, either one or both of the first check valve and the second check valve may include a resin or rubber component, and a tubular member joining step may be included in which a tubular member is brazed or welded to the third opening of the branch portion, as in the first invention. In this case, for the same reason as in the first invention, the tubular member joining step may be included in the step of preparing a three-way pipe. Spacer tube placement process It is preferable to carry out the test between 100 and 200.

[0031] [Fourth Invention] The manufacturing method of a three-way pipe unit according to the fourth invention of the present application is a method for manufacturing a three-way pipe unit including a main pipe portion having a first opening at one end and a second opening at the other end, a branch portion branching from an intermediate portion of the main pipe portion and having a third opening, a first check valve disposed between the first opening and the intermediate portion so that the direction from the first opening toward the intermediate portion is the forward direction, and a second check valve disposed between the intermediate portion and the second opening so that the direction from the intermediate portion toward the second opening is the forward direction, similar to the first to third inventions, in which a check valve device integrally including the first and second check valves is manufactured in advance, and this check valve device is inserted into the three-way pipe and fixed by a reduced diameter portion. Specifically, the method includes the following steps (1) to (4).

[0032] That is, the manufacturing method includes the steps of: (1) preparing the three-way pipe; and (2) providing a check valve device that can be housed in a main pipe, the check valve device being configured by integrating a first check valve, a cylindrical spacer pipe portion that has a circumferential opening communicating with a branch portion and can be placed in an intermediate portion of the main pipe, and a second check valve, the first check valve, the spacer pipe portion, and the second check valve, so that the first check valve, the spacer pipe portion, and the second check valve are arranged in that order, and the first check valve and the second check valve are arranged so that the direction from the first check valve to the second check valve is the forward direction. (3) a check valve device installation step of disposing the check valve device in a main pipe portion of the three-way pipe so that the peripheral opening communicates with the branch portion; and (4) after the check valve device installation step, a reduced diameter portion formation step of constricting the peripheral wall of the main pipe portion to form a first reduced diameter portion that regulates misalignment of the check valve device toward the first opening side, and constricting the peripheral wall of the main pipe portion to form a second reduced diameter portion that regulates misalignment of the check valve device toward the second opening side.

[0033] In addition, the check valve device manufacturing process may include: (5) a process for preparing a cylindrical tubular casing having a check valve installation section in which a first check valve can be installed and a spacer tube section; (6) a process for forming a reduced diameter section between the check valve installation section and the spacer tube section by constricting the tubular casing to regulate the opening operating limit of the valve body of the first check valve; (7) a process for installing the first check valve in the check valve installation section; and (8) a process for installing a second check valve at the end of the spacer tube section opposite the check valve installation section.

[0034] Furthermore, in the fourth invention, either one or both of the first check valve and the second check valve may include a resin or rubber component, and a tubular member joining step may be included in which a tubular member is brazed or welded to the third opening of the branch portion, as in the first invention. In this case, for the same reason as in the first invention, it is preferable to carry out the tubular member joining step between the three-way pipe preparing step and the check valve device installing step.

[0035] In addition, in the first to fourth inventions (including the modified example of the second invention), the step of preparing a three-way pipe may include a branch portion forming step of forming the branch portion by bulging or burring.

[0036] [Fifth Invention] The fifth invention of the present application relates to a three-way pipe unit equipped with a check valve, which has the same characteristics as the three-way pipe unit manufactured by the manufacturing method of the first invention.

[0037] Specifically, the three-way pipe unit includes a three-way pipe having a main pipe portion having a first opening at one end and a second opening at the other end, and a branch portion branching off from an intermediate portion of the main pipe portion and having a third opening; a first check valve that is inserted into the main pipe portion and disposed between the first opening and the intermediate portion so that the direction from the first opening toward the intermediate portion is the forward direction; and a second check valve that is inserted into the main pipe portion and disposed between the intermediate portion and the second opening so that the direction from the intermediate portion toward the second opening is the forward direction. and two check valves, wherein the main pipe has a pair of reduced diameter sections consisting of a first reduced diameter section and a second reduced diameter section formed by constricting the peripheral wall of the main pipe between the first opening and the intermediate section, and a pair of reduced diameter sections consisting of a third reduced diameter section and a fourth reduced diameter section formed by constricting the peripheral wall of the main pipe between the intermediate section and the second opening, the first reduced diameter section and the second reduced diameter section sandwiching the first check valve, and the third reduced diameter section and the fourth reduced diameter section sandwiching the second check valve.

[0038] [Sixth Invention] The sixth invention of the present application relates to a three-way pipe unit equipped with a check valve, which has the same characteristics as the three-way pipe unit manufactured by the manufacturing method according to the second invention.

[0039] Specifically, the three-way pipe unit includes a three-way pipe having a main pipe section having a first opening at one end and a second opening at the other end, and a branch section branching off from an intermediate section of the main pipe section and having a third opening, a first check valve inserted into the main pipe section and disposed between the first opening and the intermediate section so that the direction from the first opening toward the intermediate section is the forward direction, and a second check valve inserted into the main pipe section and disposed between the intermediate section and the second opening so that the direction from the intermediate section toward the second opening is the forward direction, and the three-way pipe includes a short pipe section having a first connection port at one end and a second connection port at the other end, and the branch section is branched off from the intermediate section of the short pipe section. the first extension pipe has a first small diameter end portion at one end having a reduced outer diameter and inner diameter so that the first small diameter end portion can be inserted into the first connection port and a first opening at the other end, the first small diameter end portion being connected to the first connection port, and a second extension pipe has a second small diameter end portion at one end having a reduced outer diameter and inner diameter so that the second connection port can be inserted into the second connection port and a second opening at the other end, the second small diameter end portion being connected to the second connection port, the first extension pipe has a first reduced diameter portion formed by constricting a peripheral wall of the first extension pipe, the second extension pipe has a second reduced diameter portion formed by constricting a peripheral wall of the second extension pipe, the first check valve is sandwiched between the first small diameter end portion and the first reduced diameter portion, and the second check valve is sandwiched between the second small diameter end portion and the second reduced diameter portion.

[0040] [Modification of the sixth aspect of the invention] The sixth invention of the present application relates to a three-way pipe unit equipped with a check valve, which has the same characteristics as a three-way pipe unit manufactured by the manufacturing method relating to the modified example of the second invention.

[0041] Specifically, the three-way pipe unit includes a three-way pipe including a main pipe portion having a first opening at one end and a second opening at the other end, and a branch portion branching off from an intermediate portion of the main pipe portion and having a third opening, a first check valve that is fitted into the main pipe portion and disposed between the first opening and the intermediate portion so that the direction from the first opening toward the intermediate portion is the forward direction, and a second check valve that is fitted into the main pipe portion and disposed between the intermediate portion and the second opening so that the direction from the intermediate portion toward the second opening is the forward direction, and the three-way pipe includes a short pipe portion having a first small diameter end portion having a reduced outer diameter at one end and a second small diameter end portion having a reduced outer diameter at the other end, and the branch portion is provided so as to branch off from the intermediate portion of the short pipe portion. the first extension pipe has a first connection port at one end that can be connected to the short pipe section by inserting a first small diameter end therein and a first opening at the other end, the first small diameter end being connected to the first connection port; and a second extension pipe has a second connection port at one end that can be connected to the short pipe section by inserting a second small diameter end therein and a second opening at the other end, the second small diameter end being connected to the second connection port, the first extension pipe has a first reduced diameter portion formed by constricting a peripheral wall of the first extension pipe, the second extension pipe has a second reduced diameter portion formed by constricting a peripheral wall of the second extension pipe, the first check valve is sandwiched between the first small diameter end and the first reduced diameter portion, and the second check valve is sandwiched between the second small diameter end and the second reduced diameter portion.

[0042] [Seventh Invention] The seventh invention of the present application relates to a three-way pipe unit equipped with a check valve, which has the same characteristics as the three-way pipe unit manufactured by the manufacturing method according to the third invention.

[0043] Specifically, the three-way pipe unit includes a three-way pipe having a main pipe section having a first opening at one end and a second opening at the other end, and a branch section branching off from an intermediate section of the main pipe section and having a third opening; a first check valve that is fitted into the main pipe section and disposed between the first opening and the intermediate section so that the direction from the first opening toward the intermediate section is the forward direction; and a second check valve that is fitted into the main pipe section and disposed between the intermediate section and the second opening so that the direction from the intermediate section toward the second opening is the forward direction. a spacer tube having openings at both ends and a peripheral opening on its peripheral surface that can communicate with the branching portion, the spacer tube being fitted into an intermediate portion of a main pipe so that the peripheral opening communicates with the branching portion, the main pipe having a first reduced diameter portion and a second reduced diameter portion that narrow a peripheral wall of the main pipe, the first check valve being sandwiched between the first reduced diameter portion and one end of the spacer tube, and the second check valve being sandwiched between the second reduced diameter portion and the other end of the spacer tube.

[0044] [Eighth Invention] The eighth invention of the present application relates to a three-way pipe unit equipped with a check valve, which has the same characteristics as the three-way pipe unit manufactured by the manufacturing method according to the fourth invention.

[0045] Specifically, the three-way pipe unit is a three-way pipe having a main pipe portion having a first opening at one end and a second opening at the other end, and a branch portion branching off from the middle of the main pipe portion and having a third opening, and a check valve device inserted into the main pipe portion.

[0046] Furthermore, the above-mentioned check valve device is formed by integrating the first check valve, spacer pipe portion, and second check valve so that the first check valve, spacer pipe portion, and second check valve are arranged in order, the first check valve is arranged between the first opening and the intermediate portion so that the direction from the first opening to the intermediate portion is the forward direction, the spacer pipe portion has a circumferential opening communicating with the branch portion and is arranged in the intermediate portion of the main pipe portion so that the circumferential opening communicates with the branch portion, the second check valve is arranged between the intermediate portion and the second opening so that the direction from the intermediate portion to the second opening is the forward direction, and the main pipe portion has a pair of reduced diameter portions formed by constricting the peripheral wall of the main pipe portion, and the check valve device is sandwiched within the main pipe portion by this pair of reduced diameter portions.

[0047] In the three-way pipe units according to the fifth to eighth aspects of the invention (including the modified example of the sixth aspect), it is preferable that the first check valve is provided with a seal member that seals between the outer circumferential surface of the first check valve and the inner circumferential surface of the main pipe, and the second check valve is provided with a seal member that seals between the outer circumferential surface of the second check valve and the inner circumferential surface of the main pipe, in order to prevent valve leakage.

[0048] [Ninth Invention] The ninth invention of the present application relates to a bridge refrigerant circuit module constructed using a three-way pipe unit according to the fifth to eighth inventions (including a modified example of the sixth invention). According to this invention, it is possible to provide a check valve bridge refrigerant circuit module having a small length dimension, which contributes to space saving of refrigerant piping.

[0049] Specifically, the bridge refrigerant circuit module is a check valve bridge refrigerant circuit module in which four check valves are connected in a bridge shape and have a first port, a second port, a third port and a fourth port as four ports for introducing or discharging refrigerant, and is equipped with a first circuit element consisting of a three-way pipe unit of any of the fifth to eighth inventions (including a modified example of the sixth invention), a second circuit element consisting of a three-way pipe unit of any of the fifth to eighth inventions (including a modified example of the sixth invention), a first three-way connecting pipe connecting the first circuit element and the second circuit element, and a second three-way connecting pipe connecting the first circuit element and the second circuit element.

[0050] The first three-way connecting pipe has a first connecting pipe that connects the first opening of the first circuit element and the first opening of the second circuit element, and a first branch pipe that branches off from the first connecting pipe and has a first end opening that communicates with the first opening of the first circuit element and the first opening of the second circuit element, and the second three-way connecting pipe has a second connecting pipe that connects the second opening of the first circuit element and the second opening of the second circuit element, and a first branch pipe that branches off from the second connecting pipe and has a first end opening that communicates with the first opening of the first circuit element and the first opening of the second circuit element. 1st circuit element and a second branch conduit having a second end opening communicating with the second opening of the second circuit element and the second opening of the second circuit element, the first end opening being the first port, the second end opening being the second port, the third opening of the first circuit element being the third port, and the third opening of the second circuit element being the fourth port. Effect of the Invention

[0051] According to the present invention, the piping in the refrigeration cycle system can be simplified, and space can be saved.

[0052] Other objects, features and advantages of the present invention will become apparent from the following detailed description of the preferred embodiments of the present invention, taken in conjunction with the accompanying drawings. In the drawings, the same reference numerals indicate the same or corresponding parts. [Brief description of the drawings]

[0053] [Figure 1] FIG. 1 is a vertical cross-sectional view showing a three-way pipe unit according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is an enlarged vertical cross-sectional view showing a check valve (closed state) provided in the three-way pipe unit of the first embodiment. [Diagram 3] FIG. 3 is an enlarged vertical cross-sectional view showing a check valve (open state) provided in the three-way pipe unit of the first embodiment. [Figure 4] FIG. 4 is a vertical cross-sectional view showing a step (a central reduced diameter portion forming step) of the manufacturing method of the three-way pipe unit according to the first embodiment. [Diagram 5]FIG. 5 is a vertical cross-sectional view showing a step of the manufacturing method of the three-way pipe unit according to the first embodiment (a state in which a central reduced diameter portion forming step is completed). [Figure 6] FIG. 6 is a vertical cross-sectional view showing a step (after a tubular member joining step has been completed) of the method for manufacturing the three-way pipe unit according to the first embodiment. [Figure 7] FIG. 7 is a vertical cross-sectional view showing one step (after the check valve installation step is completed) of the method for manufacturing the three-way pipe unit according to the first embodiment. [Figure 8] FIG. 8 is a vertical cross-sectional view showing a step (end-side reduced diameter portion forming step) of the manufacturing method of the three-way pipe unit according to the first embodiment. [Figure 9] FIG. 9 is a vertical cross-sectional view showing a step of the manufacturing method of the three-way pipe unit according to the first embodiment (a state in which an end-side reduced diameter portion for fixing a first check valve is formed in an end-side reduced diameter portion forming step). [Figure 10] FIG. 10 is a vertical cross-sectional view showing a step of the manufacturing method of the three-way pipe unit according to the first embodiment (a state in which the end-side reduced diameter portion forming step is completed). [Figure 11] FIG. 11 is a vertical cross-sectional view showing a step (a step of forming a joint portion on the first check valve side) of a manufacturing method of the three-way pipe unit according to the first embodiment. [Figure 12] FIG. 12 is a vertical cross-sectional view showing a three-way pipe unit according to a second embodiment of the present invention. [Figure 13] FIG. 13 is a vertical cross-sectional view showing a step (three-way pipe forming step) of the manufacturing method of the three-way pipe unit according to the second embodiment. [Figure 14] FIG. 14 is a vertical cross-sectional view showing a step (after a tubular member joining step has been completed) of the manufacturing method of the three-way pipe unit according to the second embodiment. [Figure 15] FIG. 15 is a vertical cross-sectional view showing one step (after the check valve installation step is completed) of the manufacturing method of the three-way pipe unit according to the second embodiment. [Figure 16] FIG. 16 is a vertical cross-sectional view showing a step of the manufacturing method of the three-way pipe unit according to the second embodiment (a state in which the first check valve is fixed in a reduced diameter portion forming step). [Figure 17] FIG. 17 is a vertical cross-sectional view showing a three-way pipe unit according to a third embodiment of the present invention. [Figure 18] FIG. 18 is a vertical cross-sectional view showing a step (a step of forming a three-way pipe) of the manufacturing method of the three-way pipe unit according to the third embodiment. [Figure 19] FIG. 19 is a vertical cross-sectional view showing a step (after a tubular member joining step has been completed) of the manufacturing method of the three-way pipe unit according to the third embodiment. [Figure 20] FIG. 20 is a vertical cross-sectional view showing one step (after the check valve installation step is completed) of the manufacturing method of the three-way pipe unit according to the third embodiment. [Figure 21] FIG. 21 is a vertical cross-sectional view showing a three-way pipe unit according to a fourth embodiment of the present invention. [Figure 22] FIG. 22 is a vertical cross-sectional view showing a step (after a tubular member joining step has been completed) of the manufacturing method of the three-way pipe unit according to the fourth embodiment. [Figure 23] FIG. 23 is an enlarged vertical cross-sectional view showing a step (a first check valve, a spacer tube, and a second check valve) of a method for manufacturing the three-way pipe unit according to the fourth embodiment. [Figure 24] FIG. 24 is a vertical cross-sectional view showing a step of the manufacturing method of the three-way pipe unit according to the fourth embodiment (a state in which a spacer pipe arranging step and a check valve installation step are completed). [Diagram 25] FIG. 25 is a vertical cross-sectional view showing a step (after the step of forming a reduced diameter portion is completed) of the manufacturing method of the three-way pipe unit according to the fourth embodiment. [Figure 26] FIG. 26 is a vertical cross-sectional view showing a three-way pipe unit according to the fifth embodiment of the present invention. [Figure 27] FIG. 27 is an enlarged vertical cross-sectional view showing a step (a check valve device manufacturing step) of the manufacturing method of the three-way pipe unit according to the fifth embodiment. [Figure 28] FIG. 28 is an enlarged vertical sectional view showing a check valve device used in the three-way pipe unit according to the fifth embodiment. [Figure 29]FIG. 29 is a vertical cross-sectional view showing a step (after a tubular member joining step has been completed) of the manufacturing method of the three-way pipe unit according to the fifth embodiment. [Diagram 30] FIG. 30 is a vertical cross-sectional view showing one step (a state in which a check valve device installation step is completed) of the manufacturing method of the three-way pipe unit according to the fifth embodiment. [Diagram 31] FIG. 31 is a vertical cross-sectional view showing a step (after the step of forming a reduced diameter portion is completed) of the manufacturing method of the three-way pipe unit according to the fifth embodiment. [Diagram 32] FIG. 32 is a vertical cross-sectional view showing a check valve bridge refrigerant circuit module according to the sixth embodiment of the present invention. [Diagram 33] FIG. 33 is a diagram showing an example (cooling operation state) of a heat pump type cooling and heating system using the check valve bridge refrigerant circuit module according to the sixth embodiment. [Diagram 34] FIG. 34 is a diagram showing an example (heating operation state) of a heat pump type cooling and heating system using the check valve bridge refrigerant circuit module according to the sixth embodiment. [Diagram 35] FIG. 35 is a diagram showing the flow of refrigerant in the check valve bridge refrigerant circuit module of the cooling and heating system (in cooling operation state). [Diagram 36] FIG. 36 is a diagram showing the flow of refrigerant in the check valve bridge refrigerant circuit module (heating operation state) of the cooling and heating system. [Figure 37] FIG. 37 is a vertical cross-sectional view showing a check valve bridge refrigerant circuit module formed using the check valve device described in Patent Document 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0054] [First embodiment] 1 to 9 show a three-way pipe unit 11 according to a first embodiment of the present invention. As shown in these figures, the three-way pipe unit 11 is provided with two check valves V1 and V2 inside a three-way pipe 12. The three-way pipe 12 has a main pipe section 13 extending in a straight line and a branch section 14 branching from a central section (intermediate section in the present invention) 13a of the main pipe section 13. The main pipe section 13 has a first opening A1 at one end through which the refrigerant flows in, and a second opening A2 at the other end through which the refrigerant flows out. The branch section 14 has a third opening A3 at its tip (the end opposite to the end communicating with the main pipe section 13) through which the refrigerant flows in or out, and a joint pipe (a tubular member in the present invention) 18 is further joined to the third opening A3.

[0055] As the tubular member to be joined to the third opening A3, various pipes other than a straight pipe, for example, an elbow pipe (a pipe bent into an L-shape), a pipe having a branch, or other deformed pipes of various shapes may be connected depending on the refrigeration cycle system to be used (the same applies to other embodiments described later). In addition, one end of the main pipe section 13 including the first opening A1 and the other end of the main pipe section 13 including the second opening A2 are formed with joint sections 17, 17a having a small pipe diameter, respectively, so that other joints or pipes can be connected.

[0056] Of the two check valves V1 and V2, the first check valve V1 is disposed between the first opening A1 and the central portion 13a, and the second check valve V2 is disposed between the central portion 13a and the second opening A2. The check valves V1 and V2 are installed so that the forward directions C1 and C2 that allow the refrigerant to pass are aligned, that is, the forward direction C1 of the first check valve V1 and the forward direction C2 of the second check valve V2 are in the same direction (from left to right in FIG. 1).

[0057] In order to prevent the main pipe 13 from being displaced in the pipe axis direction and to fix the check valves V1, V2 in the main pipe 13, a pair of reduced diameter portions 15, 16; 15a, 16a is formed at both ends of each check valve V1, V2 by constricting the pipe wall (circumferential wall) of the main pipe 13 into a ring shape (in other words, the main pipe 13 is recessed into a ring shape so that the inner diameter of the main pipe 13 is reduced), and the check valves are sandwiched between each pair of reduced diameter portions. That is, the first check valve V1 is sandwiched between a pair of reduced diameter portions formed on the left side of the main pipe 13, the central reduced diameter portion 15 close to the central portion 13a and the end side reduced diameter portion 16 close to the end of the main pipe 13, and the second check valve V2 is sandwiched between a pair of reduced diameter portions formed on the right side of the main pipe 13, the central reduced diameter portion 15a close to the central portion 13a and the end side reduced diameter portion 16a close to the end of the main pipe 13. Each of the check valves V1, V2 has an outer diameter approximately equal to the inner diameter of the main pipe portion 13 so that it can be inserted into the main pipe portion 13 without any gaps.

[0058] In this embodiment, as each check valve (first check valve V1 and second check valve V2), a valve assembly included in the check valve device described in Patent Document 1 is used (the same applies to other embodiments described later), but this is not limited to this, and other structures may be used as long as they have the function of a check valve (allowing the refrigerant to pass in the forward direction and preventing the flow of refrigerant in the reverse direction).

[0059] As shown enlarged in Figures 2 and 3, the valve assembly comprises a cylindrical guide member 4 having one end bent inwardly at a bent portion 4b, a valve element 3 housed in this guide member 4 and whose valve opening limit is regulated by the bent portion 4b (the limit position of the movement of the valve element 3 in the valve opening direction is defined), a valve seat member 5 attached to the other end of the guide member 4 and provided with a valve seat 5a against which the valve element 3 comes into contact and separates, and a seal member 6 for sealing between the outer peripheral surface of the valve seat member 5 and the inner peripheral surface of the main pipe portion 13.

[0060] The seal member 6 is, for example, a rubber O-ring, and is fixed by being fitted into a groove 5b formed on the outer circumferential surface of the valve seat member 5. The valve body 3 has four wing-shaped portions 3b extending in the axial direction (the direction in which the valve body 3 moves) on the back side (the side closer to the bent portion 4b) of the valve portion 3a. The valve seat member 5 is made of a metal such as brass, the valve body 3 is made of, for example, a resin material, and the three-way pipe 12 is made of a metal material such as copper or stainless steel.

[0061] As shown in FIG. 2, in this valve assembly (first check valve V1 and second check valve V2), when the pressure on the bent portion 4b side (the right side in FIG. 2 / also referred to as the "outlet side") is higher than the pressure on the valve seat member 5 side (the left side in FIG. 2 / also referred to as the "inlet side"), the valve portion 3a of the valve body 3 abuts against the valve seat 5a of the valve seat member 5, closing the valve orifice and blocking the flow of refrigerant.

[0062] On the other hand, when the pressure on the valve seat member 5 side (inlet side) becomes higher than the pressure on the bent portion 4b side (outlet side), the valve element 3 moves toward the bent portion 4b side (rightward) along the inner surface of the guide member 4 (cylindrical base portion 4a) as shown in Fig. 3, causing the valve portion 3a to separate from the valve seat 5a and opening the valve port, and the refrigerant flows through the gaps between the four vane portions 3b and passes through the valve assemblies V1 and V2 (see arrow F in Fig. 3).Then, the valve element 3 stops by abutting against the bent portion 4b, and the open valve state is maintained.

[0063] A method of manufacturing the three-way pipe unit 11 will be described with reference to FIGS.

[0064] First, a three-way pipe 12 having a main pipe section 13 and a branch section 14 is prepared (three-way pipe preparation process). This three-way pipe 12 can be made by plastically deforming the central section of a straight pipe by bulging processing (or burring processing) to form the branch section 14 branching off from the straight pipe (main pipe section 13) (the same applies to the short three-way pipes 32, 42 of the second and third embodiments described below).

[0065] Next, the central reduced diameter portions 15, 15a are formed on both sides of the branched portion 14 (the central portion 13a of the main pipe portion 13) of the prepared three-way pipe 12 (central reduced diameter portion forming process). Specifically, as shown in FIG. 4, a cylindrical jig (cylindrical metal mold) 22 that can be fitted into the main pipe portion 13 is inserted into the main pipe portion 13 from its left end until it is inserted near the formation position of the central reduced diameter portion 15 on the left side, and then the main pipe portion 13 is pressed from above and below with an upper mold 21a and a lower mold 21b of a split mold press 21 (see arrow S) to form a ring-shaped reduced diameter portion 15. The upper mold 21a and the lower mold 21b are arranged to form a ring-shaped opening smaller than the outer diameter of the main pipe portion 13 when they are put together, and the inner peripheral surface of this opening squeezes (depresses) the peripheral wall of the main pipe portion 13 to form the reduced diameter portion 15.

[0066] During press processing, the jig 22 is placed only on one side of the reduced diameter section 15 (the end side of the main pipe section 13), and not on the central section 13a side. However, since no check valve (or any other components or parts, etc.) is installed on the central section 13a side, even if some irregular deformation occurs, it is acceptable (it will not impair the function of the three-way pipe unit 11).

[0067] The right-side central reduced diameter portion 15a is formed in the same manner as the left-side portion. The state after both central reduced diameter portions 15, 15a are formed is shown in Fig. 5. Note that this central reduced diameter portion forming step may be performed after the tubular member joining step described next and before the check valve installation step described below.

[0068] After the central reduced diameter portions 15, 15a are formed, the joint pipe 18 is brazed and joined to the branch pipe 14 as shown in FIG. 6 (tubular member joining process). By joining the joint pipe 18 before arranging the check valves V1, V2, the metallic valve seat member 5, the resin valve body 3, and the rubber seal member 6 included in the check valves V1, V2 are prevented from being deformed or altered by heating during joining. Therefore, according to this embodiment (the same applies to the second to fifth embodiments described later), the check valves V1, V2 can be arranged in a position close to the branch portion 14 (the central portion 13a of the main pipe portion), and the overall length of the three-way pipe unit 11 can be shortened. As already mentioned, the tubular member joined to the branch pipe 14 may be not only a straight pipe, but also an irregular pipe having another shape such as an elbow pipe.

[0069] After joining the coupling pipe 18, the first check valve V1 is inserted from the left end of the main pipe section 13 and pushed in until it abuts against the left-side central reduced diameter section 15 as shown in FIG. 7, and the second check valve V2 is pushed in from the right side of the main pipe section 13 until it abuts against the right-side central reduced diameter section 15a (check valve installation process).

[0070] Then, as shown in Fig. 8, a cylindrical jig 22 is inserted to a position near the first check valve V1 (a position where a gap is formed between the first check valve V1 and the reduced diameter portion 16 to be formed), and a reduced diameter portion (end side reduced diameter portion) 16 is formed by a split die press 21 in the same manner as the central side reduced diameter portion 15 (see Fig. 9). As a result, the first check valve V1 is sandwiched between the central side reduced diameter portion 15 and the end side reduced diameter portion 16, and is fixed in the main pipe portion 13 without shifting to the left or right. Also, the end side reduced diameter portion 16a is formed by pressing in the same manner as the first check valve V1, and the second check valve V2 is sandwiched between the both reduced diameter portions 15a, 16a and fixed in the main pipe portion 13 (see Fig. 10) (end side reduced diameter portion forming process).

[0071] In the above description, the central reduced diameter portions 15, 15a and the end reduced diameter portions 16, 16a are press-formed, but roll swaging may be performed using a roll die. In this embodiment, both check valves (first check valve V1 and second check valve V2) are disposed in the main pipe portion 13, and then the end reduced diameter portions 16, 16a for fixing the ends of both check valves V1, V2 are formed, but the first check valve V1 may be disposed in the main pipe portion 13, the end reduced diameter portion 16 for fixing the first check valve V1 is formed, and then the second check valve V2 may be disposed in the main pipe portion 13, and the end reduced diameter portion 16a for fixing the second check valve V2 may be formed (the same applies to the second and third embodiments described later).

[0072] 11, a cylindrical jig (cylindrical metal mold) 24 is inserted into the left end of the main pipe portion 13, and a rotating die 23 (23a, 23b) is used to draw it by spinning to form a joint portion 17 with a small pipe diameter. If a joint portion 17a is similarly formed at the right end of the main pipe portion 13, the three-way pipe unit 11 of this embodiment shown in FIG. 1 is completed.

[0073] Second Embodiment 12 shows a three-way pipe unit 31 according to a second embodiment of the present invention. As shown in the figure, this three-way pipe unit 31, like the three-way pipe unit 11 according to the first embodiment, is provided with check valves V1 and V2 on both the left and right sides of a branching portion 34 of the three-way pipe, but the support structure on the center side of each check valve V1 and V2 is different from that of the first embodiment. Hereinafter, the same reference numerals are used for configurations similar to those of the first embodiment, and duplicated explanations are omitted, and differences are mainly described (the same applies to the third and subsequent embodiments described later).

[0074] In this embodiment, the three-way pipe (main pipe portion) is composed of three members, and the connection portion of these members is used as a support means for the center side of the check valves V1 and V2. Specifically, the three-way pipe 31 in this embodiment is composed of a short three-way pipe 32 having a shorter main pipe portion than that in the first embodiment (this short main pipe portion is referred to as the "short pipe portion"), a first extension pipe 35 which is a straight tubular member connected to an opening 33a on one end side of the short pipe portion 33, and a second extension pipe 36 which is a straight tubular member connected to an opening 33b on the other end side of the short pipe portion 33.

[0075] Each extension pipe (first extension pipe 35 and second extension pipe 36) has an inner diameter into which the check valves V1, V2 can be inserted (inserted so as to fit just right) similar to the main pipe portion 13 of the first embodiment. Also, each extension pipe 35, 36 has small-diameter end portions 35a, 36a at one end (the end portion connected to the short three-way pipe 32) formed with an outer diameter small enough to be inserted into the short three-way pipe 32 and an inner diameter small enough to abut and support the check valves V1, V2 inserted into the extension pipes 35, 36.

[0076] To manufacture the three-way pipe unit 31 of this embodiment, a short three-way pipe 32, a first extension pipe 35, and a second extension pipe 36 are prepared as shown in Fig. 13, and the first extension pipe 35 is joined to the short three-way pipe 32 by inserting and brazing the small diameter end 35a into one end opening 33a of the short pipe section 33 of the short three-way pipe 32 as shown in Fig. 14, and the second extension pipe 36 is joined to the short three-way pipe 32 by inserting and brazing the small diameter end 36a into the other end opening 33b of the short pipe section 32, thereby forming a three-way pipe (three-way pipe forming process). Also, the joint pipe 18 is brazed and joined to the third opening A3 of the short three-way pipe 32 (tubular member joining process).

[0077] Then, as shown in Figure 15, the first check valve V1 is inserted into the first extension pipe 35 from the other end (the end opposite the connection side end with the short three-way pipe 32) of the first extension pipe 35 and pushed in until it hits the small diameter end 35a, and the second check valve V2 is inserted into the second extension pipe 36 from the other end (the end opposite the connection side end with the short three-way pipe 32) of the second extension pipe 36 and pushed in until it hits the small diameter end 36a (check valve installation process).

[0078] 16, by forming the end side reduced diameter portion 16 in the same manner as in the first embodiment, the first check valve V1 can be sandwiched between the small diameter end portion 35a and the end side reduced diameter portion 16 and fixed within the first extension pipe 35. Similarly, the second check valve V2 can be fixed within the second extension pipe 36 by forming the end side reduced diameter portion 16a (see FIG. 17) (reduced diameter portion forming step). Note that, in this embodiment as well, the check valves (first check valve V1 and second check valve V2) are installed so that the forward direction is the same.

[0079] Third Embodiment 17 shows a three-way pipe unit 41 according to a third embodiment of the present invention. Similar to the three-way pipe unit 31 of the second embodiment, this three-way pipe unit 41 is configured with a short three-way pipe 42 and two extension pipes 45, 46, but the small diameter ends 43a, 43b are provided on the short three-way pipe 42 side, not on the extension pipes 45, 46 side.

[0080] During manufacturing, as shown in Figures 18 and 19, the small diameter ends 43a, 43b at both ends of the short pipe section 43 of the short three-way pipe 42 are inserted into the first extension pipe 45 and the second extension pipe 46, respectively, and brazed to form a three-way pipe (three-way pipe forming process), and the joint pipe 18 is brazed and joined to the branch section 44 of the short three-way pipe 42 (tubular member joining process).

[0081] Then, as shown in Figure 20, the first check valve V1 is inserted into the first extension pipe 45 and pushed in until it hits the small diameter end 43a of the short three-way pipe 42, and the second check valve V2 is inserted into the second extension pipe 46 and pushed in until it hits the small diameter end 43b of the short three-way pipe 42 (check valve installation process).

[0082] 16, by forming the end side reduced diameter portion 16, the first check valve V1 can be fixed in the first extension pipe 45, and by forming the end side reduced diameter portion 16a, the second check valve V2 can be fixed in the second extension pipe 46 (reduced diameter portion forming process). Even in this embodiment, the check valves V1, V2 can be fixed in the three-way pipe by the small diameter end portions 43a, 43b and the end side reduced diameter portions 16, 16a.

[0083] [Fourth embodiment] FIG. 21 shows a three-way pipe unit 51 according to the fourth embodiment of the present invention. In this embodiment, a spacer pipe is interposed between the first check valve V1 and the second check valve V2 to support the central sides of both check valves V1, V2.

[0084] To explain the manufacturing process in more detail, a three-way pipe 12 similar to that of the first embodiment is prepared as shown in Fig. 22, and a joint pipe 18 is brazed to the branch section 14 in advance (tubular member joining process), and a first check valve V1, a spacer pipe 52, and a second check valve V2 are prepared as shown in Fig. 23. The spacer pipe 52 is a short, straight tubular member with both ends open, and has the same outer diameter as the check valves V1, V2 so that it can be inserted into the main pipe section 13 of the three-way pipe 12. The spacer pipe 52 also has a peripheral opening 53 on its peripheral surface that communicates between the inside of the spacer pipe 52 and the branch section 14.

[0085] As shown in Figure 24, the spacer pipe 52 is inserted into the central portion 13a of the main pipe portion 13 of the three-way pipe 12 so that the peripheral opening 53 faces the branch portion 14 (third opening A3) (spacer pipe arrangement process), and the first check valve V1 is inserted into one end of the main pipe portion 13 and the second check valve V2 is inserted into the other end of the main pipe portion 13 and brought into close contact with the spacer pipe 52 (check valve installation process).

[0086] 25, by forming a pair of end-side reduced diameter portions 16, 16a in the main pipe portion 13 of the three-way pipe 12 so as to sandwich the first check valve V1, spacer pipe 52, and second check valve V2 in their entirety (reduced diameter portion forming step), the first check valve V1, spacer pipe 52, and second check valve V2 can be fixed as a whole in the main pipe portion 13. Note that in the spacer pipe arrangement step, a recess for fixing the spacer pipe 52 in the main pipe portion 13 may be formed by punching. Also, the spacer pipe 52 may be joined at the same time in the tubular member joining step.

[0087] Fifth embodiment 26 shows a three-way pipe unit 61 according to a fifth embodiment of the present invention. As shown in the figure, this three-way pipe unit 61 is constructed by integrating the first check valve V1, the spacer pipe 52 (the spacer portion 62 in this embodiment), and the second check valve V2 of the fourth embodiment into a check valve device 66, which is fabricated in advance and then installed in the three-way pipe 12.

[0088] That is, as shown in Figures 27 and 28, the check valve device 66 is formed by integrating the guide member 4 of the first check valve V1 with the spacer tube 52 by extending the guide member 4 to the outflow side, and forming a guide portion 63 having the same function as the guide member 4 (guiding the axial movement of the valve body 3), and a spacer portion 62 having a peripheral opening 53 like the spacer tube 52 and having the same function.

[0089] Also, instead of the bent portion 4b, a reduced diameter portion 64, which has a narrowed peripheral wall, is formed between the guide portion 63 and the spacer portion 62. This reduced diameter portion 64 has the same function as the bent portion 4b, and when the valve body 3 moves toward the spacer portion 62 when the valve is opened from the closed state shown in Fig. 28, it stops when it comes into contact with the reduced diameter portion 64, and the first check valve V1 is fully opened. The reduced diameter portion 64 may be formed in the same manner as the central reduced diameter portion 15 of the first embodiment (Figs. 4 and 5) before the valve body 3 and the valve seat member 5 are installed in the guide portion 63.

[0090] The inlet side (valve seat member 5) of the second check valve V2 is fixed to the end portion (the end portion opposite to the reduced diameter portion 64) of the spacer portion 62. The valve seat member 5 of the second check valve V2 is formed with a step portion 65 (see FIG. 27) that can be fitted into the spacer portion 62.

[0091] In the manufacturing process, the check valve device 66 is manufactured (check valve device manufacturing process), and the three-way pipe 12 is prepared as shown in Fig. 29, and the joint pipe 18 is brazed and joined to the branching section 14 (tubular member joining process). Then, as shown in Fig. 30, the check valve device 66 is inserted into the main pipe section 13 of the three-way pipe 12, and the check valve device 66 is arranged in the center of the main pipe section 13 so that the peripheral opening 53 of the spacer section 62 faces the branching section 14 (third opening A3) (check valve device arrangement process). Note that in the check valve device arrangement process, only the first check valve V1 with the spacer section 62 may be inserted into the main pipe section 13, and in this state, a recess for fixing the spacer section 62 to the main pipe section 13 may be formed by punching, and then the second check valve V2 may be inserted into the main pipe section 13 from the second opening A2 and arranged so as to abut against the spacer section 62.

[0092] Then, similarly to the fourth embodiment, by forming a pair of end-side reduced diameter portions 16, 16a on the peripheral wall of the main pipe portion 13, the check valve device 66 can be fixed inside the main pipe portion 13. That is, it is sufficient to form reduced diameter portions 16, 16a on both the left and right sides of the check valve device 66 so as to sandwich the check valve device 66, as shown in Fig. 31 (reduced diameter portion forming step).

[0093] Sixth Embodiment 32 shows a check valve bridge refrigerant circuit module 71 according to a sixth embodiment of the present invention. As shown in the figure, this refrigerant circuit module 71 combines two three-way pipe units 11 according to the present invention to form a bridge circuit having four ports P1, P2, P3, and P4 through which the refrigerant flows in and out.

[0094] Specifically, the module 71 has a first circuit element 72 consisting of a three-way pipe unit 11 according to the first embodiment, a second circuit element 73 also consisting of a three-way pipe unit 11 according to the first embodiment, and a first three-way connecting pipe 74 and a second three-way connecting pipe 77 that connect the first circuit element 72 and the second circuit element 73.

[0095] The first three-way connecting pipe 74 has a first connecting pipe 75 connecting the first opening A1 of the first circuit element 72 and the first opening A1 of the second circuit element 73, and a first branch pipe 76 branching from an intermediate portion of the first connecting pipe 75 and having a first end opening 76a at its end communicating with the first opening A1 of the first circuit element 72 and the first opening A1 of the second circuit element 73. The second three-way connecting pipe 77 has a second connecting pipe 78 connecting the second opening A2 of the first circuit element 72 and the second opening A2 of the second circuit element 73, and a second branch pipe 79 branching from an intermediate portion of the second connecting pipe 78 and having a second end opening 79a at its end communicating with the second opening A2 of the first circuit element 72 and the second opening A2 of the second circuit element 73.

[0096] The first end opening 76a is the first port P1, the second end opening 79a is the second port P2, the tip opening of the coupling tube 18 joined to the third opening A3 of the first circuit element 72 is the third port P3, and the tip opening of the coupling tube 18 joined to the third opening A3 of the second circuit element 73 is the fourth port P4.

[0097] In this embodiment, the three-way pipe unit 11 according to the first embodiment is used as the first circuit element 72 and the second circuit element 73, but instead of these, any of the three-way pipe units 31, 41, 51, 61 according to the second to fifth embodiments may be used, or other three-way pipe units configured based on the present invention may be used. In addition, hereinafter, the first check valve V3 of the second circuit element 73 will be referred to as the "third check valve" and the second check valve V4 of the second circuit element 73 will be referred to as the "fourth check valve" to distinguish them from the first check valve V1 and second check valve V2 of the first circuit element 72.

[0098] The module according to this embodiment can be used, for example, in the following heat pump type heating and cooling system.

[0099] [Heating and cooling system] As shown in Figures 33 and 34, this heating and cooling system includes an outdoor unit 81, an indoor unit 91, and a bridge refrigerant circuit 71 provided between the outdoor unit 81 and the indoor unit 91. The outdoor unit 81 includes a compressor 82, a four-way valve 83 that switches the refrigerant flow path, an outdoor heat exchanger 84 which is a heat source side heat exchanger, an outdoor fan 85, an outdoor expansion valve 86, and an accumulator 87. The indoor unit 91 includes an indoor heat exchanger 92 which is a user side heat exchanger, an indoor fan 93, and an indoor expansion valve 94.

[0100] The bridge refrigerant circuit 71 is configured by the module 71 according to this embodiment, and has a first port P1 connected to an outlet piping of an indoor heat exchanger 92 and a second port P2 connected to an inlet piping of the indoor heat exchanger 92 via an indoor expansion valve 94. In addition, a third port P3 is connected to an outdoor heat exchanger 84 via a four-way valve 83, and a fourth port P4 is connected to the outdoor heat exchanger 84 via an outdoor expansion valve 86.

[0101] [Cooling operation] 33 and 35 show the flow of refrigerant during cooling operation. As shown in these figures, during cooling operation, the four-way valve 83 forms an internal flow path shown by a solid line in FIG. 33, and the high-temperature, high-pressure refrigerant discharged from the compressor 82 flows into the outdoor heat exchanger 84 through the four-way valve 83. The refrigerant that has been heat exchanged with the outdoor air and condensed in the outdoor heat exchanger 84 flows into the bridge circuit 71 from the fourth port P4, passes through the fourth check valve V4, flows out of the bridge circuit 71 through the second port P2, and flows into the indoor unit 91. In the indoor unit 91, the refrigerant is rapidly decompressed by the indoor expansion valve 94 and its temperature is reduced. The refrigerant that has been heat exchanged with the indoor air and evaporated in the indoor heat exchanger 92 flows into the bridge circuit 71 from the first port P1, passes through the first check valve V1, flows out of the bridge circuit 71 through the third port P3, and is returned to the outdoor unit 81. In the outdoor unit 81 , the refrigerant passes through a four-way valve 83 and an accumulator 87 in this order, is compressed again by the compressor 82 , and is sent to the outdoor heat exchanger 84 .

[0102] Here, the solid line with an arrow in Fig. 35 indicates the flow of high-pressure refrigerant, and the dashed line with an arrow indicates the flow of low-pressure refrigerant. In the bridge circuit module 71 of this embodiment, during cooling, high-pressure refrigerant flows in from the fourth port P4, passes through the fourth check valve V4, and flows out from the second port P2, so that the pressure of the outflow side of the second check valve V2 and the third check valve V3 is higher than that of the inflow side, and these second check valve V2 and third check valve V3 are in a closed state. Therefore, the low-pressure refrigerant that flows in from the first port P1 passes through the first check valve V1 without passing through the third check valve V3, and flows out of the bridge circuit 71 from the third port P3 without passing through the second check valve V2.

[0103] [Heating operation] Figures 34 and 36 show the flow of refrigerant during heating operation. As shown in these figures, during heating operation, the four-way valve 83 forms an internal flow path shown by a solid line in Figure 34, and the high-temperature, high-pressure refrigerant discharged from the compressor 82 is sent to the bridge circuit 71 via the four-way valve 83, flows into the bridge circuit 71 from the third port P3, passes through the second check valve V2, and flows out from the second port P2 to be sent to the indoor unit 91. Then, the refrigerant that has been heat exchanged with the indoor air and condensed in the indoor heat exchanger 92 flows into the bridge circuit 71 from the first port P1, passes through the third check valve V3, flows out of the bridge circuit 71 through the fourth port P4, and is returned to the outdoor unit 81. In the outdoor unit 81, the refrigerant is suddenly decompressed by the outdoor expansion valve 86, and the temperature drops. The refrigerant then exchanges heat with the outside air in the outdoor heat exchanger 84 and evaporates. The refrigerant passes through the four-way valve 83 and the accumulator 87 in that order, and is compressed again in the compressor 82 and sent to the indoor unit 91.

[0104] Here, as in Fig. 35, the solid line with arrows in Fig. 36 indicates the flow of high-pressure refrigerant, and the dashed line with arrows indicates the flow of low-pressure refrigerant. In the bridge circuit module 71 of this embodiment, during heating, high-pressure refrigerant flows in from the third port P3, passes through the second check valve V2, and flows out from the second port P2, so that the pressure of the outflow side of the first check valve V1 and the fourth check valve V4 is higher than that of the inflow side, and these first check valve V1 and the fourth check valve V4 are in a closed state. Therefore, the low-pressure refrigerant that flows in from the first port P1 passes through the third check valve V3 without passing through the first check valve V1, and flows out of the bridge circuit 71 from the fourth port P4 without passing through the fourth check valve V4.

[0105] Although the embodiments of the present invention have been described above, the present invention is not limited to these, and it will be apparent to those skilled in the art that various modifications can be made within the scope of the claims.

[0106] For example, the heating and cooling system equipped with the module 71 of the sixth embodiment is shown as one example, and the three-way pipe unit and check valve bridge refrigerant circuit module of the present invention can be used in heating and cooling systems having various refrigerant circuit configurations different from those of the above embodiment, such as systems equipped with multiple outdoor units 81 and multiple indoor units 91, or systems equipped with various other devices such as piping, flow path switching means, and flow path switches to enable defrost operation, and other refrigeration cycle systems. [Explanation of symbols]

[0107] 1,66 Check valve device 2a Large diameter section 2b,2c Small diameter part 2d, 2e Tapered section 2f Inlet port 2g Exit Port 3 Valve body 3a Valve part 3b vane 4 Guide member 4a Cylindrical base 4b Bend section 5 Valve seat material 5a Valve seat 5b Groove 6 Sealing material 7 Valve Assembly 11,31,41,51,61 Three-way pipe unit 12 Three-way tube 13 Main pipe section 13a Center of main pipe 14,34,44 Branch 15,15a Center side reduced diameter part 16,16a End side reduced diameter section 17,17a Joint 18 Joint pipe 21 Split press 21a upper mold 21b Lower mold 22,24 Jig 23, 23a, 23b Rotational mold 32,42 Short three-way pipe 33,43 Short pipe section 33a One end opening of the short pipe section 33b Other end opening of short pipe section 35,45 1st extension pipe 35a,36a,43a,43b Small diameter end 36,46 2nd extension pipe 52 Spacer tube 53 Peripheral opening 62 Spacer part 63 Information Department 64 Reduced diameter part 65 Step 71 Bridge refrigerant circuit (check valve bridge refrigerant circuit module) 72 1st circuit element 73 Second circuit element 74 1st three-way connecting pipe 75 First connecting pipe 76 First Branch Pipe 76a 1st end opening 77 2nd three-way connecting pipe 78 Second connecting pipe 79 Second Branch Pipe 79a 2nd end opening 81 Outdoor unit 82 Compressor 83 Four-way valve 84 Outdoor heat exchanger 85 Outdoor fan 86 Outdoor expansion valve 87 Accumulator 91 Indoor unit 92 Indoor heat exchanger 93 Indoor Fan 94 Indoor expansion valve A1 1st opening A2 2nd opening A3 3rd opening C1,C2 forward direction F Refrigerant flow P1 First port P2 2nd port P3 3rd port P4 4th port V1 First check valve V2 Second check valve V3 3rd check valve V4 4th check valve

Claims

1. a three-way pipe including a main pipe portion having a first opening at one end and a second opening at the other end, and a branch portion branching off from an intermediate portion of the main pipe portion and having a third opening; a first check valve disposed between the first opening and the intermediate portion such that a direction from the first opening toward the intermediate portion is a forward direction; a second check valve disposed between the intermediate portion and the second opening such that a direction from the intermediate portion toward the second opening is a forward direction; Three-way pipe unit with A method for producing preparing a short three-way pipe having a short pipe section with a first small diameter end portion at one end and a second small diameter end portion at the other end, the short pipe section having a branching portion branching off from a middle portion of the short pipe section; preparing a first extension pipe capable of being connected to the short pipe portion by inserting the first small diameter end portion; preparing a second extension pipe capable of being connected to the short pipe portion by inserting the second small diameter end portion; a three-way pipe forming process for connecting the first extension pipe and the second extension pipe to the short three-way pipe by fitting and inserting the first small diameter end portion into one end of the first extension pipe and fitting and inserting the second small diameter end portion into one end of the second extension pipe, making the other end of the first extension pipe the first opening and the other end of the second extension pipe the second opening, and forming the three-way pipe by the short three-way pipe, the first extension pipe, and the second extension pipe; a check valve installation process, which is performed after the three-way pipe forming process, includes inserting the first check valve into the first extension pipe from the first opening at the other end of the first extension pipe and abutting the first small diameter end of the short three-way pipe to position the first check valve, and inserting the second check valve into the second extension pipe from the second opening at the other end of the second extension pipe and abutting the second small diameter end of the short three-way pipe to position the second check valve; a reduced diameter portion forming process, in which a peripheral wall of the first extension pipe is narrowed to form a first reduced diameter portion that restricts displacement of the first check valve toward the other end side, and a peripheral wall of the second extension pipe is narrowed to form a second reduced diameter portion that restricts displacement of the second check valve toward the other end side; Characterized in that it comprises A method for manufacturing a three-way pipe unit.

2. one or both of the first check valve and the second check valve include a component made of resin or rubber, The manufacturing method of the three-way pipe unit includes a tubular member joining step of brazing or welding a tubular member to the third opening, The tubular member joining step is carried out between the three-way pipe forming step and the check valve installation step. A method for manufacturing the three-way pipe unit according to claim 1.

3. a three-way pipe including a main pipe portion having a first opening at one end and a second opening at the other end, and a branch portion branching off from an intermediate portion of the main pipe portion and having a third opening; a first check valve disposed between the first opening and the intermediate portion such that a direction from the first opening toward the intermediate portion is a forward direction; a second check valve disposed between the intermediate portion and the second opening such that a direction from the intermediate portion toward the second opening is a forward direction; Three-way pipe unit with A method for producing providing the three-way pipe; preparing a spacer tube having openings at both ends, a peripheral opening on a peripheral surface that can communicate with the branch portion, and that can be fitted into the main pipe portion; a spacer tube arrangement step of arranging the spacer tube in the intermediate portion of the main pipe portion; a check valve installation step, which is performed after the spacer pipe arrangement step, of inserting the first check valve into the main pipe from one end side thereof and abutting it against the spacer pipe to position the first check valve, and inserting the second check valve into the main pipe from the other end side thereof and abutting it against the spacer pipe to position the second check valve; a reduced diameter portion forming step of constricting a peripheral wall of the main pipe portion to form a first reduced diameter portion that restricts positional displacement of the first check valve toward the one end side, and constricting a peripheral wall of the main pipe portion to form a second reduced diameter portion that restricts positional displacement of the second check valve toward the other end side; Characterized in that it comprises A method for manufacturing a three-way pipe unit.

4. one or both of the first check valve and the second check valve include a component made of resin or rubber, The manufacturing method of the three-way pipe unit includes a tubular member joining step of brazing or welding a tubular member to the third opening, The tubular member joining step is carried out between the three-way pipe preparing step and the spacer pipe arranging step. A method for manufacturing the three-way pipe unit according to claim 3.

5. a three-way pipe including a main pipe portion having a first opening at one end and a second opening at the other end, and a branch portion branching off from an intermediate portion of the main pipe portion and having a third opening; a first check valve disposed between the first opening and the intermediate portion such that a direction from the first opening toward the intermediate portion is a forward direction; a second check valve disposed between the intermediate portion and the second opening such that a direction from the intermediate portion toward the second opening is a forward direction; Three-way pipe unit with A method for producing providing the three-way pipe; a check valve device fabrication process for fabricating a check valve device that can be housed in the main pipe portion, the check valve device comprising the first check valve, a cylindrical spacer pipe portion that has a circumferential opening communicating with the branch portion and that can be disposed in the intermediate portion of the main pipe portion, and the second check valve, the first check valve, the spacer pipe portion, and the second check valve being integrated together so that the first check valve, the spacer pipe portion, and the second check valve are arranged in order, and the first check valve and the second check valve are arranged so that the direction from the first check valve to the second check valve is a forward direction; a check valve device installation step of disposing the check valve device in the main pipe portion of the three-way pipe so that the peripheral opening communicates with the branch portion; a reduced diameter portion forming step of constricting a peripheral wall of the main pipe portion to form a first reduced diameter portion that restricts positional displacement of the check valve device toward the first opening side, and a reduced diameter portion forming step of constricting a peripheral wall of the main pipe portion to restrict positional displacement of the check valve device toward the second opening side, after the check valve device installation step; Characterized in that it comprises A method for manufacturing a three-way pipe unit.

6. The check valve device manufacturing process includes: preparing a cylindrical tubular housing including a check valve installation portion in which the first check valve can be installed and the spacer tube portion; a reduced diameter portion forming step of forming a reduced diameter portion between the check valve installation portion and the spacer tube portion by constricting the tubular housing so as to regulate an opening operation limit of the valve body of the first check valve; installing the first check valve in the check valve installation section; installing the second check valve at an end of the spacer pipe portion opposite to the check valve installation portion; Includes A method for manufacturing the three-way pipe unit according to claim 5.

7. one or both of the first check valve and the second check valve include a component made of resin or rubber, The manufacturing method of the three-way pipe unit includes a tubular member joining step of brazing or welding a tubular member to the third opening, The tubular member joining step is carried out between the step of preparing the three-way pipe and the step of installing the check valve device. A method for manufacturing the three-way pipe unit according to claim 5 or 6.

8. The step of preparing a three-way pipe includes: A branched portion forming step of forming the branched portion by bulging or burring. Includes A method for manufacturing the three-way pipe unit according to any one of claims 1 to 7.

9. a three-way pipe including a main pipe portion having a first opening at one end and a second opening at the other end, and a branch portion branching off from an intermediate portion of the main pipe portion and having a third opening; a first check valve that is inserted into the main pipe portion and disposed between the first opening and the intermediate portion such that a direction from the first opening toward the intermediate portion is a forward direction; a second check valve that is inserted into the main pipe portion and disposed between the intermediate portion and the second opening such that a direction from the intermediate portion toward the second opening is a forward direction; A three-way pipe unit having The three-way pipe is a short three-way pipe having a short pipe section with a first small diameter end section at one end and a second small diameter end section at the other end, the short pipe section being branched from a middle section of the short pipe section; a first extension pipe having a first connection port at one end and the first opening at the other end, the first small diameter end of which is connected to the first connection port; a second extension pipe having a second connection port at one end thereof into which the second small diameter end portion is inserted to be connected to the short pipe portion, and having the second opening at the other end thereof, the second extension pipe having the second small diameter end portion connected to the second connection port; It consists of: The first extension pipe has a first reduced diameter portion formed by constricting a peripheral wall of the first extension pipe, The second extension pipe has a second reduced diameter portion formed by constricting a peripheral wall of the second extension pipe, the first check valve is sandwiched between the first small diameter end portion and the first reduced diameter portion, The second check valve is sandwiched between the second small diameter end portion and the second reduced diameter portion. A three-way pipe unit characterized by:

10. a three-way pipe including a main pipe portion having a first opening at one end and a second opening at the other end, and a branch portion branching off from an intermediate portion of the main pipe portion and having a third opening; a first check valve that is inserted into the main pipe portion and disposed between the first opening and the intermediate portion such that a direction from the first opening toward the intermediate portion is a forward direction; a second check valve that is inserted into the main pipe portion and disposed between the intermediate portion and the second opening such that a direction from the intermediate portion toward the second opening is a forward direction; A three-way pipe unit having the three-way pipe unit further includes a spacer pipe having openings at both ends, a peripheral opening on a peripheral surface that can communicate with the branching portion, and the spacer pipe is inserted into the intermediate portion of the main pipe portion so that the peripheral opening communicates with the branching portion, The main pipe portion has a first reduced diameter portion and a second reduced diameter portion formed by constricting a peripheral wall of the main pipe portion, the first check valve is sandwiched between the first reduced diameter portion and one end of the spacer tube, The second check valve is sandwiched between the second reduced diameter portion and the other end of the spacer tube. A three-way pipe unit characterized by:

11. a three-way pipe including a main pipe portion having a first opening at one end and a second opening at the other end, and a branch portion branching off from an intermediate portion of the main pipe portion and having a third opening; A check valve device inserted into the main pipe portion; A three-way pipe unit having the check valve device is configured by integrating the first check valve, the spacer pipe portion, and the second check valve such that the first check valve, the spacer pipe portion, and the second check valve are arranged in order, the first check valve is disposed between the first opening and the intermediate portion such that a direction from the first opening toward the intermediate portion is a forward direction; the spacer pipe portion has a peripheral opening communicating with the branch portion, and is disposed in the intermediate portion of the main pipe portion such that the peripheral opening communicates with the branch portion; the second check valve is disposed between the intermediate portion and the second opening such that a direction from the intermediate portion toward the second opening is a forward direction; The main pipe portion has a pair of reduced diameter portions formed by constricting a peripheral wall of the main pipe portion, The check valve device is sandwiched within the main pipe by the pair of reduced diameter portions. A three-way pipe unit characterized by:

12. the first check valve includes a seal member that seals between an outer circumferential surface of the first check valve and an inner circumferential surface of the main pipe portion, The second check valve includes a seal member that seals between an outer circumferential surface of the second check valve and an inner circumferential surface of the main pipe portion. A three-way pipe unit according to any one of claims 9 to 11.

13. A check valve bridge refrigerant circuit module including four check valves connected in a bridge shape and including a first port, a second port, a third port, and a fourth port as four ports for introducing or discharging a refrigerant, A first circuit element comprising the three-way pipe unit according to any one of claims 9 to 12; A second circuit element comprising the three-way pipe unit according to any one of claims 9 to 12; a first three-way connecting pipe connecting the first circuit element and the second circuit element; a second three-way connecting pipe connecting the first circuit element and the second circuit element; Equipped with The first three-way connecting pipe is a first connection pipe connecting a first opening of the first circuit element and a first opening of the second circuit element; a first branch conduit branching off from the first connecting conduit and having a first end opening communicating with the first opening of the first circuit element and the first opening of the second circuit element; having The second three-way connecting pipe is a second connection pipe connecting the second opening of the first circuit element and the second opening of the second circuit element; a second branch conduit branching off from the second connecting conduit and having a second end opening communicating with the second opening of the first circuit element and the second opening of the second circuit element; having The first end opening is designated as the first port, the second end opening is designated as the second port, the third opening of the first circuit element is designated as the third port, and the third opening of the second circuit element is designated as the fourth port. A check valve bridge refrigerant circuit module.

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