Method for manufacturing piping structure, piping structure, heat exchanger, and indoor unit for air conditioning device

Abstract

This method for manufacturing a piping structure includes a preparation step for preparing a pipe retention member (110) having a second surface (112) in which a recess (114) communicating with a through-hole (113) is formed. The recess (114) defines a circumferential groove (114a) that surrounds a pipe (160) between the recess and the outer peripheral surface of the pipe (160) inserted through the through-hole (113). In a brazing step, brazing material (180) is supplied to the circumferential groove (114a), and the supplied brazing material (180) is melted to braze the outer peripheral surface of the piping (160) to the pipe retention member (110). In a connecting step, a facing member is connected to the pipe retention member (110) to which the pipe (160) has been brazed, with an elastic sealing member interposed therebetween, the sealing member being elastically compressed by a first surface (111) and the facing member in a state of surrounding the pipe (160).

Description

Piping structure manufacturing method, piping structure, heat exchanger, and indoor unit for air conditioner

[0001] The present disclosure relates to a piping structure manufacturing method, a piping structure, a heat exchanger, and an indoor unit for an air conditioner.

[0002] A piping structure constituting a heat exchanger is known, as disclosed in Patent Document 1. This piping structure includes a metal piping holding member having a plate-shaped portion, a metal piping having an end portion penetrating the plate-shaped portion, and an opposing member connected to the piping holding member in a state facing the end portion of the piping and the plate-shaped portion.

[0003] The piping structure also includes an elastic seal member interposed between the opposing member and a first surface of the plate-like portion, the first surface being a surface of the plate-like portion facing the opposing member. The elastic seal member surrounds the piping while being elastically compressed by the first surface and the opposing member.

[0004] Japanese Utility Model Application Laid-Open Publication No. 02-140182

[0005] The above-mentioned piping structure can be obtained by a manufacturing method that involves a soldering process in which the portion of the outer surface of the piping that penetrates the plate-shaped portion is soldered to the plate-shaped portion, and a connecting process in which the opposing member is connected to the piping holding member via an elastic sealing member pressed against the first surface of the plate-shaped portion.

[0006] The pipe is inserted into a through hole formed in the plate-shaped portion. In the brazing process, a brazing material is placed around the pipe on the first surface of the plate-shaped portion and melted. The molten brazing material flows into the gap between the pipe and the inner surface of the through hole. The brazing is completed when the flowed brazing material solidifies.

[0007] However, with the above manufacturing method, there is a concern that the molten brazing material may flow and spread to the area of ​​the first surface where the elastic sealing member is pressed (hereinafter referred to as the "sealed area"). The brazing material that flows and spreads to the sealed area increases the surface roughness of the sealed area. The greater the surface roughness, the worse the sealing performance at the sealed area.

[0008] Here, "sealing performance" refers to the performance against the fluid flowing through the piping. Specifically, "sealing performance" refers to the ability to prevent fluid from leaking outward from the tight contact area between the elastic seal member and the sealed portion of the first surface.

[0009] Although the possibility of the brazing material flowing and spreading to the sealing location can be reduced by moving the sealing location away from the piping, moving the sealing location away from the piping increases the diameter of the elastic sealing member surrounding the piping, which in turn increases the size of the piping structure.

[0010] An object of the present disclosure is to provide a piping structure manufacturing method that is less likely to impair sealing performance at the point where the elastic sealing member is pressed and that prevents the piping structure from becoming larger, a piping structure that can be obtained by the piping structure manufacturing method, and a heat exchanger and an indoor unit for an air conditioner that include the piping structure.

[0011] A piping structure manufacturing method according to the present disclosure includes a preparation step, a brazing step, and a connection step. In the preparation step, a metal pipe holding member is prepared. The pipe holding member has a plate-shaped portion formed in a plate shape having a first surface and a second surface opposite the first surface in a thickness direction. A through hole penetrating the thickness direction and opening to the first and second surfaces is formed in the plate-shaped portion. In the brazing step, a metal pipe is inserted into the through hole of the pipe holding member and brazed to the inner surface of the through hole. In the connection step, a counter member facing the first surface is connected to the pipe holding member. In the preparation step, a pipe holding member is prepared, the second surface of which has a recess communicating with the through hole, the recess defining a circumferential groove surrounding the pipe between the second surface and the outer peripheral surface of the pipe inserted into the through hole. In the brazing step, a brazing material is supplied into the circumferential groove of the plate-shaped portion through which the pipe is inserted into the through hole, and the supplied brazing material is melted to braze the outer peripheral surface of the pipe to the plate-shaped portion. In the above-mentioned connecting process, the pipe holding member, having the pipe soldered to the plate-shaped portion, is connected to the opposing member by sandwiching an elastic sealing member that is elastically compressed by the first surface of the pipe holding member and the opposing member while surrounding the pipe.

[0012] In the piping structure manufacturing method according to the present disclosure, brazing material is supplied to the circumferential groove of the plate-shaped portion through which the piping is inserted into the through hole, and the outer surface of the piping is brazed to the plate-shaped portion by melting the brazing material.

[0013] Therefore, compared to a manufacturing method in which the brazing filler metal is placed on the first surface, the molten brazing filler metal is less likely to flow and spread onto the first surface. The fact that excess brazing filler metal can accumulate in the circumferential groove on the second surface also contributes to suppressing the flow and spreading of the brazing filler metal onto the first surface. Therefore, the brazing filler metal is less likely to adhere to the area on the first surface where the elastic sealing member is pressed, and therefore the sealing performance at the area where the elastic sealing member is pressed is less likely to be impaired.

[0014] Furthermore, since the brazing material is prevented from flowing and spreading onto the first surface, it is not necessary to place the portion of the first surface against which the elastic seal member is pressed away from the piping, which prevents the piping structure from becoming large.

[0015] FIG. 1 is a conceptual diagram showing the configuration of an air conditioning device according to the first embodiment; FIG. 2 is a perspective view showing a main part of a piping structure constituting an indoor heat exchanger according to the first embodiment; FIG. 3 is a partial cross-sectional view showing a part of a piping structure according to the first embodiment; FIG. 4 is an exploded view showing the relationship between a piping retaining plate and an opposing member according to the first embodiment; FIG. 5 is a conceptual diagram for explaining a piping structure manufacturing method according to a comparative embodiment; FIG. 6 is a flow chart of a piping structure manufacturing method according to the first embodiment;

[0016] Hereinafter, an air conditioner according to an embodiment will be described with reference to the drawings, in which the same or corresponding parts are designated by the same reference numerals.

[0017] 1, an air conditioner 300 according to this embodiment includes a refrigerant closed circuit 310 through which a refrigerant circulates. The refrigerant closed circuit 310 forms a refrigeration cycle using the refrigerant.

[0018] Specifically, the refrigerant closed circuit 310 has a compressor 311 that compresses the refrigerant, an outdoor heat exchanger 312 that functions as a condenser that condenses the compressed refrigerant, an expander 313 that expands the condensed refrigerant, a relay heat exchanger 314 that functions as an evaporator that evaporates the expanded refrigerant, and a gas-liquid separator 315 that allows the evaporated refrigerant to return to the compressor 311 while capturing the liquid refrigerant that has not completely evaporated.

[0019] The refrigerant closed circuit 310 also has a four-way valve 316 that reverses the direction of refrigerant flow in the refrigeration cycle. Fig. 1 illustrates a state in which the outdoor heat exchanger 312 functions as a condenser and the relay heat exchanger 314 functions as an evaporator. Because the four-way valve 316 can reverse the direction of refrigerant flow, the outdoor heat exchanger 312 also functions as an evaporator, and the relay heat exchanger 314 also functions as a condenser.

[0020] The air conditioning system 300 also includes a heat medium closed circuit 320 that is independent of the refrigerant closed circuit 310. A heat medium circulates in the heat medium closed circuit 320. The heat medium is a fluid different from the refrigerant circulating in the refrigerant closed circuit 310. In this embodiment, water is used as the heat medium.

[0021] The heat medium closed circuit 320 has a temperature adjustment section 321 passing through the inside of the relay heat exchanger 314. In other words, the relay heat exchanger 314 is shared by the refrigerant closed circuit 310 and the heat medium closed circuit 320.

[0022] The heat medium closed circuit 320 also has an indoor heat exchanger 200 that exchanges heat with the air in the space to be air-conditioned (hereinafter referred to as indoor air), a relay pipe 322 that is a flow path connecting the indoor heat exchanger 200 to the temperature adjustment unit 321, and a pump 323 that circulates the heat medium between the indoor heat exchanger 200 and the temperature adjustment unit 321 through the relay pipe 322.

[0023] The air conditioner 300 also has an outdoor fan 330 that promotes heat exchange between the refrigerant and outdoor air (hereinafter referred to as outside air) in the outdoor heat exchanger 312. The outdoor fan 330 forms an airflow of outside air that passes through the outdoor heat exchanger 312.

[0024] The air conditioner 300 also has an indoor fan 340 that promotes heat exchange between the heat medium and the indoor air in the indoor heat exchanger 200. The indoor fan 340 forms an airflow of the indoor air that passes through the indoor heat exchanger 200.

[0025] The relay heat exchanger 314 exchanges heat between the refrigerant circulating through the refrigerant closed circuit 310 and the heat medium circulating through the heat medium closed circuit 320 .

[0026] Specifically, when the relay heat exchanger 314 functions as an evaporator in the refrigerant closed circuit 310, the heat medium circulating in the heat medium closed circuit 320 is cooled in the temperature adjustment unit 321. As a result, the cooled heat medium flows through the indoor heat exchanger 200, and the space to be air-conditioned is cooled.

[0027] On the other hand, when the relay heat exchanger 314 functions as a condenser in the refrigerant closed circuit 310, the heat medium circulating in the heat medium closed circuit 320 is heated in the temperature adjustment unit 321. As a result, the heated heat medium flows through the indoor heat exchanger 200, and the space to be air-conditioned is heated.

[0028] In this way, the refrigerant closed circuit 310 serves as a collaborative device that adjusts the temperature of the heat medium flowing through the indoor heat exchanger 200 using a refrigeration cycle.

[0029] Of the components of the air conditioner 300 described above, the indoor heat exchanger 200 and the indoor fan 340 constitute an indoor unit 300a for the air conditioner that is placed indoors, which is the space to be air-conditioned.

[0030] The compressor 311, the outdoor heat exchanger 312, the gas-liquid separator 315, the outdoor fan 330, and the four-way valve 316 constitute an outdoor unit 300b for an air conditioner that is placed outdoors.

[0031] The expander 313, the relay heat exchanger 314 including the temperature adjustment unit 321, and the pump 323 constitute an air conditioning relay unit 300c. The air conditioning relay unit 300c is installed indoors in a location isolated from the space to be air-conditioned.

[0032] The greatest feature of the air conditioning device 300 according to this embodiment is the manufacturing method and configuration of the indoor heat exchanger 200. Therefore, the following describes the indoor heat exchanger 200. The indoor heat exchanger 200 is an example of a heat exchanger according to the present disclosure.

[0033] 2 shows the external appearance of the indoor heat exchanger 200. The main part of the indoor heat exchanger 200 is composed of a piping structure 100. The piping structure 100 includes fins 170 through which the above-mentioned indoor air passes, a plurality of pipes 160 inserted through the fins 170, and headers 150 fixed to the ends of the plurality of pipes 160.

[0034] The pipes 160 are formed of a metal, specifically, copper or an alloy containing copper. The heat medium described above flows through each of the multiple pipes 160. The pipes 160 are thermally coupled to the fins 170. Heat exchange occurs between the heat medium flowing through the pipes 160 and the inside air passing through the fins 170 through the pipes 160 and the fins 170.

[0035] The header 150 has an inlet 151 and an outlet 152. The inlet 151 and the outlet 152 are each connected to the relay pipe 322 shown in FIG. 1. That is, the heat medium whose temperature has been adjusted by the temperature adjustment unit 321 shown in FIG. 1 flows into the header 150 through the inlet 151. In addition, the heat medium that has exchanged heat with the inside air described above through the pipe 160 and the fins 170 flows out from the outlet 152 toward the temperature adjustment unit 321 shown in FIG. 1.

[0036] The header 150 has (i) a distribution function for distributing the heat medium flowing in through the inlet 151 to multiple pipes 160, (ii) a confluence function for converging the heat medium flowing through the multiple pipes 160 and guiding it to the outlet 152, and (iii) a return function for introducing the heat medium flowing out from the end of one pipe 160 into the end of another pipe 160.

[0037] The header 150 has a shape with one direction as its longitudinal direction when viewed from a line of sight parallel to the longitudinal direction of the ends of the multiple pipes 160 to which the header 150 is fixed. To facilitate the following explanation, a virtual right-handed XYZ Cartesian coordinate system is defined in which the direction parallel to the longitudinal direction of the header 150 is the Z-axis direction and the direction parallel to the longitudinal direction of the ends of the multiple pipes 160 is the X-axis direction.

[0038] With respect to the X-axis direction, the direction from the header 150 toward the fins 170 is the positive direction of the X-axis, and the direction from the fins 170 toward the header 150 is the negative direction of the X-axis.

[0039] The detailed configuration of the piping structure 100 will be described below. The drawings referred to below also include an XYZ Cartesian coordinate system. For ease of understanding, the drawings referred to below will show only two or one of the multiple pipes 160 shown in FIG. 2 as a representative.

[0040] As shown in Figure 3, the header 150 has a pipe holding plate 110 that holds a plurality of pipes 160, an opposing member 120 that is arranged opposite the pipe holding plate 110, an elastic sealing member 130 that is interposed between the opposing member 120 and the pipe holding plate 110, and screws 140 that fix the opposing member 120 to the pipe holding plate 110.

[0041] 4, the pipe holding plate 110 is formed in a plate shape. The plate-shaped pipe holding plate 110 has a first surface 111 which is a front surface, and a second surface 112 which is a back surface opposite to the first surface in the thickness direction of the pipe holding plate 110.

[0042] The thickness direction of the pipe holding plate 110 coincides with the X-axis direction. The second surface 112 faces the fin 170 shown in Fig. 3 in the X-axis direction. The pipe holding plate 110 is an example of a pipe holding member and a plate-shaped portion according to the present disclosure.

[0043] A through hole 113 is formed in the pipe holding plate 110 for each pipe 160. The through hole 113 penetrates the pipe holding plate 110 in the thickness direction. The through hole 113 is open to the first surface 111 and the second surface 112.

[0044] Each of the pipes 160 is inserted through a through hole 113. As described above, the pipes 160 are made of metal. The pipe holding plate 110 is also made of metal, specifically, copper or an alloy containing copper.

[0045] Each pipe 160 is inserted into the through hole 113 and brazed to the inner surface of the through hole 113. Specifically, a brazing material 181 that brazes the pipe 160 to the pipe holding plate 110 is interposed in the gap between the outer surface of the pipe 160 and the inner surface of the through hole 113.

[0046] The facing member 120 is disposed opposite the first surface 111 of the pipe holding plate 110. An elastic seal member 130 provided for each pipe 160 is interposed between the facing member 120 and the first surface 111.

[0047] The facing member 120 is made of resin, and the elastic seal member 130 is made of an elastic body, specifically, an O-ring made of rubber.

[0048] 3 , opposing member 120 is pressed against first surface 111 in the thickness direction of pipe holding plate 110 by screws 140. Elastic seal member 130 provided for each pipe 160 surrounds the end of that pipe 160 in a state where it is elastically compressed by opposing member 120 and first surface 111.

[0049] That is, the ends of the multiple pipes 160 that each pass through the pipe holding plate 110 are surrounded by the elastic seal member 130 and are disposed inside the opposing member 120. The opposing member 120 defines a flow path for the heat medium therein to achieve the above-mentioned (i) distribution function, (ii) confluence function, and (iii) turnback function. Note that only a portion of the heat medium flow path is shown in Figures 3, 4, etc.

[0050] The above-described piping structure 100 can be obtained by a manufacturing method including a brazing step and a connecting step. In the brazing step, the plurality of pipes 160 are brazed to the pipe holding plate 110. In the connecting step, the opposing member 120 is connected to the pipe holding plate 110 to which the plurality of pipes 160 are brazed via the elastic seal member 130.

[0051] Clad materials, in which a metal layer made of metal is covered with a brazing material layer made of brazing material, are known as components used for brazing. Because the surface layer of the clad material is made of brazing material, supplying brazing material for brazing can be omitted when using a clad material. However, the pipe holding plate 110 according to this embodiment does not have a brazing material layer. In other words, the pipe holding plate 110 is not a clad material. Therefore, a process of supplying brazing material to necessary locations is required to braze the pipe 160 to the pipe holding plate 110.

[0052] In the following, a manufacturing method according to a comparative embodiment will be described in order to illustrate the problem to be solved by this embodiment.

[0053] 5 , in the connecting step according to the comparative embodiment, the pipe holding plate 110 to which the plurality of pipes 160 are brazed is held in a position in which the first surface 111 is positioned higher in the direction of gravity than the second surface 112. Fins 170 have already been attached to the pipes 160. With this position maintained, the opposing member 120 is connected to the pipe holding plate 110.

[0054] The reason for positioning the first surface 111 higher in the direction of gravity than the second surface 112 is to position the fins 170 and piping 160, which are heavy objects, lower in the direction of gravity than the piping holding plate 110.

[0055] In addition, in order to eliminate the need to change the position of the pipe holding plate 110 between the soldering process and the connecting process, soldering in the soldering process is also performed by maintaining the pipe holding plate 110 in a position in which the first surface 111 is positioned higher in the direction of gravity than the second surface 112.

[0056] Specifically, in the brazing process, a solid brazing material to be melted (hereinafter referred to as the "melting brazing material") is supplied to the first surface 111 of the pipe holding plate 110. Specifically, the melting brazing material is formed in a ring shape. The melting brazing material is placed in a manner that surrounds the end of the pipe 160 that protrudes from the first surface 111 in the negative X-axis direction.

[0057] The molten brazing material is then melted by heating. The liquefied molten brazing material then flows down into the gap between the outer peripheral surface of the pipe 160 and the inner surface of the through-hole 113. The molten brazing material that has flowed down solidifies and becomes a solid brazing material 181, thereby completing the brazing process. Note that the brazing material 181 shown in Figures 3 and 4 is also solid, and is a re-solidified molten brazing material. Here, "re-solidification" means that the solid molten brazing material melts by heating and then returns to a solid state.

[0058] However, in the manufacturing method according to this comparative example, there is a concern that the liquefied molten brazing material may flow and spread to the sealing area 111a on the first surface 111 where the elastic sealing member 130 is pressed. When the molten brazing material that has flowed and spread to the sealing area 111a re-solidifies and becomes the brazing material 181, it may cause the surface roughness of the sealing area 111a to increase.

[0059] The greater the surface roughness of the sealed portion 111a, the more likely it is that a minute gap will be formed between the sealed portion 111a and the elastic seal member 130, thereby deteriorating the sealing performance at the sealed portion 111a.

[0060] Note that the possibility of the molten brazing material flowing and spreading to the sealing point 111a is reduced if the sealing point 111a is located away from the piping 160. However, the location of the sealing point 111a away from the piping 160 increases the diameter of the elastic sealing member 130 surrounding the piping 160, which in turn increases the size of the piping structure 100.

[0061] The comparative example has been described above. Now, we return to the description of this embodiment, which solves the above-mentioned problems.

[0062] A piping structure manufacturing method according to this embodiment will be described with reference to Fig. 6. Fins 170 are attached to a plurality of pipes 160 in advance (fin attachment step S10). Meanwhile, in this embodiment, prior to brazing the pipes 160 to the pipe holding plate 110, the pipe holding plate 110 is prepared with a recess formed therein for storing liquefied molten brazing material (preparation step S20).

[0063] 7 , recessed portion 114 is formed in second surface 112 of pipe holding plate 110 at the position of through hole 113. Recessed portion 114 is recessed in the negative X-axis direction relative to the region of second surface 112 other than recessed portion 114, and is connected to through hole 113. Recessed portion 114 defines, between itself and the outer peripheral surface of pipe 160 inserted through through hole 113, a circumferential groove 114a that surrounds pipe 160 all around.

[0064] 6 will be continued with reference to Fig. 7. Next, the outer peripheral surface of pipe 160 is brazed to pipe holding plate 110 having recessed portion 114 formed therein (brazing step S30). Brazing step S30 will be specifically described below.

[0065] First, as shown by the dashed line in Fig. 7, the molten brazing material 180 is supplied to the circumferential groove 114a defined by the recess 114 and the outer peripheral surface of the pipe 160. Specifically, the ring-shaped molten brazing material 180, which is shaped to fit into the circumferential groove 114a, is placed in the circumferential groove 114a. Flux is applied to the molten brazing material 180 as needed.

[0066] Next, the end of the pipe 160 to which the fin 170 has been attached in the fin attachment step S10 described above is passed through the ring-shaped molten brazing material 180 and the through-hole 113. This results in a state in which the molten brazing material 180 is placed in the circumferential groove 114a surrounding the pipe 160.

[0067] Next, the molten brazing filler metal 180 is melted by heating. For heating, it is preferable to use a means capable of locally heating the area where the molten brazing filler metal 180 is placed, specifically, infrared rays, a burner flame, etc. However, the pipe holding plate 110 with the pipe 160 inserted therethrough may be placed in a heating furnace, and the molten brazing filler metal 180 may be melted by heating with the heating furnace.

[0068] Regardless of which heating method is adopted, in this embodiment, the melting brazing material 180 is melted while the pipe holding plate 110 is held in a position in which the second surface 112 is positioned higher in the direction of gravity than the first surface 111.

[0069] Since the molten brazing material 180 is disposed in the peripheral groove 114a, the molten brazing material 180 that has been liquefied by heating can accumulate in the peripheral groove 114a.

[0070] The liquefied molten brazing material 180 flows down from the bottom of the circumferential groove 114a into the gap between the outer circumferential surface of the pipe 160 and the inner surface of the through-hole 113. The liquefied molten brazing material 180 re-solidifies, thereby completing the brazing process.

[0071] By the above brazing process, the gap between the outer peripheral surface of the pipe 160 and the inner surface of the through hole 113 is filled with the brazing material 181. As described above, the brazing material 181 is solid, and is the molten brazing material 180 that has been re-solidified.

[0072] Note that after the brazing process, the brazing material 181 may remain in the circumferential groove 114a. While Fig. 7 illustrates a configuration in which the brazing material 181 is filled in the circumferential groove 114a, the brazing material 181 may be attached in the form of a layer to the inner surface of the circumferential groove 114a. In other words, the brazing material 181 may remain in at least a portion of the interior of the circumferential groove 114a. Furthermore, after the brazing process, the brazing material 181 may not remain in the circumferential groove 114a.

[0073] Next, the opposing member 120 shown in Fig. 4 is connected to the piping holding plate 110 to which the piping 160 is brazed via the elastic sealing member 130 shown in Fig. 4 (connecting step S40). As described above, the elastic sealing member 130 is interposed between the first surface 111 and the opposing member 120 in a manner such that the elastic sealing member 130 is pressed against the sealing location 111a of the first surface 111. In other words, the elastic sealing member 130 is sandwiched between the first surface 111 and the opposing member 120. In this manner, the piping structure 100 according to this embodiment is completed.

[0074] As described above, in the piping structure manufacturing method according to this embodiment, molten brazing material 180 is supplied to the circumferential groove 114a of the piping holding plate 110 in which the piping 160 is inserted into the through hole 113, and the supplied molten brazing material 180 is melted to solder the outer surface of the piping 160 to the piping holding plate 110.

[0075] Therefore, compared to a comparative example in which the molten brazing material 180 is disposed on the first surface 111, the liquefied molten brazing material 180 is less likely to flow and spread onto the first surface 111. The fact that excess molten brazing material 180 can accumulate in the circumferential groove 114a also contributes to suppressing the flow and spread of the molten brazing material 180 onto the first surface 111. Even if the liquefied molten brazing material 180 overflows from the circumferential groove 114a, the overflowed molten brazing material 180 can flow and spread onto the second surface 112, but it does not flow and spread onto the first surface 111.

[0076] Therefore, the liquefied molten brazing material 180 is unlikely to adhere to the sealing portion 111a of the first surface 111, and the sealing performance at the sealing portion 111a is unlikely to be impaired.

[0077] Furthermore, since the flow of the molten brazing filler metal 180 onto the first surface 111 is suppressed from spreading, it is not necessary to place the sealing portion 111a on the first surface 111 away from the piping 160. As a result, the size of the piping structure 100 is prevented from increasing. This will be described in detail below.

[0078] 7, when the piping structure 100 is viewed from a line of sight parallel to the X-axis, the area surrounded by the sealed portion 111a has a portion that contains only one end of the piping 160. In this portion, the connection between the end of the piping 160 and a hole that leads to a flow path in the opposing member 120 to achieve the above-described (i) distribution function or (ii) confluence function can be configured in a space-saving manner.

[0079] Furthermore, although not shown, when viewed from a line of sight parallel to the X-axis, the piping structure 100 has a portion in which the area surrounded by the sealed portion 111a includes the ends of the multiple pipes 160. In such a portion, the connections between the ends of the multiple pipes 160 and holes leading to the flow paths for realizing the aforementioned (iii) turning-back function in the opposing member 120 can be configured in a space-saving manner. Furthermore, bringing the sealed portion 111a close to the ends of the multiple pipes 160 also contributes to saving space in the flow paths themselves for realizing the aforementioned (iii) turning-back function in the opposing member 120.

[0080] 7 illustrates a configuration in which the sealing portion 111a is disposed at a position farther from the piping 160 than a virtual projection area obtained by projecting the circumferential groove 114a onto the first surface 111 in the X-axis direction. According to this embodiment, the flow of the molten brazing material 180 is suppressed from spreading to the first surface 111, so the sealing portion 111a may be disposed at a position overlapping at least a portion of the virtual projection area. That is, the sealing portion 111a may be disposed closer to the piping 160. This contributes to further miniaturization of the piping structure 100.

[0081] Second Embodiment A configuration that can further reduce the possibility of the molten brazing material 180 adhering to the sealing portion 111a will be described below.

[0082] As shown in FIG. 8, the pipe holding plate 110 according to this embodiment is formed with a peripheral bank 115 in addition to the recessed portion 114 described above.

[0083] The circumferential bank 115 is formed on the first surface 111 of the pipe holding plate 110 at the position of the through hole 113. The circumferential bank 115 protrudes in the negative X-axis direction beyond the area of ​​the first surface 111 other than the circumferential bank 115. The circumferential bank 115 is formed in a shape that surrounds the entire periphery of the pipe 160 that is inserted through the through hole 113.

[0084] The circumferential bank 115 has an apex 115a that is farthest in the X-axis direction from the area of ​​the first surface 111 other than the circumferential bank 115, and an outer peripheral surface 115b that connects the apex 115a and the first surface 111. The apex 115a in this embodiment extends in a planar shape parallel to the first surface 111.

[0085] The outer peripheral surface 115b rises from an area of ​​the first surface 111 other than the peripheral bank 115. The outer peripheral surface 115b is located closer to the pipe 160 than the sealing point 111a that surrounds the pipe 160, i.e., is located radially inward of the sealing point 111a.

[0086] Here, the "radial direction" refers to an imaginary line parallel to the X-axis and perpendicular to the imaginary line representing the central axis of through-hole 113. The radial direction is also the direction of the radius of the portion of pipe 160 inserted into through-hole 113. With regard to the radial direction, the direction approaching pipe 160 is referred to as the "radially inward direction."

[0087] The dimension of the outer peripheral surface 115b in the X-axis direction, i.e., the height of the circumferential bank 115 protruding from the region of the first surface 111 other than the circumferential bank 115, is smaller than the entire length in the X-axis direction of the through-hole 113. In other words, the circumferential bank 115 in this embodiment defines a part of the through-hole 113 in the X-axis direction.

[0088] The circumferential bank 115 can be formed by press working. As the press working, doweling, which forms the circumferential bank 115 as a dowel, is preferred. With doweling, the first surface 111 is protruded by an amount corresponding to the depression of the second surface 112, thereby forming the depression 114 and the circumferential bank 115 together.

[0089] However, the circumferential bank 115 may also be formed by welding another member to the first surface 111, by building up, or the like. Alternatively, the circumferential bank 115 may be formed indirectly by pressing a portion of the plate material that is the material of the pipe holding plate 110 that will become the first surface 111, thereby forming the first surface 111 that is set back in the positive direction of the X-axis from the circumferential bank 115.

[0090] In this embodiment, the above-described pipe holding plate 110 is prepared in a preparation step S20 shown in Fig. 6. In a brazing step S30 shown in Fig. 6, similarly to the first embodiment, the molten brazing material 180 is melted in a state in which the pipe holding plate 110 is held in an orientation in which the second surface 112 is positioned higher than the first surface 111 in the direction of gravity.

[0091] A portion of the molten brazing material 180 that has been liquefied by heating accumulates in the peripheral groove 114a, and the remainder flows down from the bottom of the peripheral groove 114a into the gap between the outer circumferential surface of the pipe 160 and the inner surface of the through-hole 113. The molten brazing material 180 that has further flowed down can accumulate at the top 115a of the peripheral bank 115 and at the corner defined by the top 115a and the outer circumferential surface of the pipe 160. The liquefied molten brazing material 180 re-solidifies, completing the brazing process.

[0092] Thereafter, in a connecting step S40 shown in FIG. 6, the opposing member 120 is connected to the pipe holding plate 110 via the elastic seal member 130 that surrounds the circumferential bank 115.

[0093] According to this embodiment, in the brazing step S30, the top 115a of the circumferential bank 115 is located lower in the direction of gravity than the area of ​​the first surface 111 other than the circumferential bank 115. Therefore, it is unlikely that the molten brazing material 180 accumulated at the top 115a will flow along the outer peripheral surface 115b of the circumferential bank 115 and reach the first surface 111. In other words, the molten brazing material 180 is prevented from flowing and spreading radially outward from the top 115a. Therefore, the possibility of the molten brazing material 180 adhering to the sealing portion 111a can be further reduced. Note that "radially outward" here means a direction away from the pipe 160 in the radial direction.

[0094] Furthermore, by adopting a configuration in which the sealed portion 111a is located close to the outer peripheral surface 115b of the surrounding bank 115, it is possible to reduce the size of the piping structure 100. The other configurations and processes are the same as those in the first embodiment.

[0095] 8 illustrates an example of a circumferential bank 115 that defines a portion of the through-hole 113 in the X-axis direction. The circumferential bank 115 may define the entire through-hole 113 in the X-axis direction. A specific example of this will be described below.

[0096] 9 , in the pipe holding plate 110 according to this embodiment, the height of the peripheral bank 115 protruding from the region of the first surface 111 other than the peripheral bank 115 is equal to or greater than the total length in the X-axis direction of the through-hole 113. In other words, in this embodiment, the entire length of the through-hole 113 in the X-axis direction is defined by the peripheral bank 115.

[0097] In this embodiment, such a pipe holding plate 110 is prepared in a preparation step S20 shown in Fig. 6. The other configurations and steps are the same as those in embodiment 2. This embodiment also provides the same effects as those in embodiment 2.

[0098] 3 may be divided into a portion brazed to the pipe holding plate 110 (hereinafter referred to as the short pipe) and a portion to which the fins 170 are attached (hereinafter referred to as the long pipe). After the short pipe is brazed to the pipe holding plate 110, the long pipe may be joined to the short pipe via a joint. A specific example of this is described below.

[0099] 10 shows a flowchart of the piping structure manufacturing method according to the present embodiment. The preparation step S20 and the connection step S40 are the same as those in any of the first to third embodiments. In this embodiment, the brazing step S30, the fin attachment step S10, and the piping connection step S50 are different from those in the first embodiment.

[0100] 11 is a conceptual diagram for explaining the piping structure manufacturing method according to the present embodiment. Hereinafter, the explanation will be continued along with FIG. 10 while still referring to FIG.

[0101] In the brazing step S30 according to the present embodiment, short pipes 161 not including fins 170 are brazed to pipe holding plate 110. Note that short pipes 161 are an example of pipes brazed to pipe holding plate 110.

[0102] That is, the configuration of the pipe holding plate 110 is the same as that shown in FIGS. 7 to 9, but the pipes 160 shown in FIGS. 7 to 9 are replaced with short pipes 161 that do not have fins 170.

[0103] On the other hand, in the fin attachment process S10 according to the present embodiment, the fins 170 are attached to the long pipe 162 that is longer than the short pipe 161. The long pipe 162 has an end formed with a joint 162a that is connected to the end of the short pipe 161.

[0104] Next, in this embodiment, after the above-mentioned brazing process S30 and fin attachment process S10, a long pipe 162 with fins 170 attached is joined to the short pipe 161 brazed to the pipe holding plate 110 (pipe connection process S50).

[0105] In the pipe connecting step S50, the end of the portion of the short pipe 161 that extends from the second surface 112 in a direction from the first surface 111 toward the second surface 112 is fitted into the joint portion 162a of the long pipe 162. Then, the end of the short pipe 161 and the joint portion 162a of the long pipe 162 are connected. Note that this connection is realized by a known method, specifically, brazing.

[0106] As described above, the piping 160 in this embodiment has a short piping 161 soldered to the inner surface of the through hole 113 of the piping holding plate 110, a long piping 162 that is longer than the short piping 161, and a joint portion 162a that connects the long piping 162 to the end of the portion of the short piping 161 that extends from the second surface 112.

[0107] Furthermore, fins 170 are not attached to short pipes 161. Therefore, even when a method of heating pipe holding plate 110 and short pipes 161 in a heating furnace to melt brazing filler metal 180 (hereinafter referred to as a furnace brazing method) is employed in brazing step S30, fins 170 do not need to be arranged in the heating furnace.

[0108] That is, in the case of the first embodiment, since the fins 170 are attached to the pipes 160, when the furnace brazing method is employed, the fins 170 must also be placed in the heating furnace. In this case, it is necessary to limit the environment inside the heating furnace to a temperature and atmosphere that will not adversely affect the thin fins 170.

[0109] In contrast, in the present embodiment, since it is not necessary to place fins 170 in the heating furnace, the environment inside the heating furnace can be set without considering adverse effects on the fins 170. Specifically, the temperature inside the heating furnace can be set higher than when the fins 170 are also placed in the heating furnace. Furthermore, nitrogen, which suppresses oxidation of the pipe holding plate 110 and the short pipes 161, can be used as the gas filling the inside of the heating furnace.

[0110] Furthermore, as a method for heating the brazing filler metal 180, a method for locally heating the brazing filler metal 180 (hereinafter referred to as a local brazing method) may be employed by applying a burner flame, infrared rays, or the like to the brazing filler metal 180. Even when the local brazing method is employed, according to this embodiment, the fins 170 do not get in the way, so that the local heating of the brazing filler metal 180 can be easily performed.

[0111] Furthermore, in the brazing step S30, each short pipe 161 is independent and not connected to other short pipes 161, so that the short pipes 161 can be easily inserted into the through holes 113. That is, in the case of the first embodiment, the multiple pipes 160 are grouped together by the fins 170, so that the multiple pipes 160 need to be aligned with the multiple through holes 113 all at once. On the other hand, in the present embodiment, the short pipes 161 are independent, so that the alignment with the through holes 113 and the insertion into the through holes 113 can be performed for each short pipe 161.

[0112] Furthermore, since no fins 170 are attached to each of the short pipes 161, the order of inserting the short pipes 161 into the through holes 113 and arranging the ring-shaped molten brazing filler metal 180 can be set arbitrarily. That is, unlike the first embodiment, the ring-shaped molten brazing filler metal 180 can be arranged in the circumferential groove 114a after inserting the short pipes 161 into the through holes 113. As described above, according to this embodiment, the work required in the brazing step S30 can be simplified.

[0113] In this embodiment, as in the first embodiment, brazing is performed with pipe holding plate 110 held in an orientation in which second surface 112 is positioned higher in the direction of gravity than first surface 111. However, because short pipes 161 are lighter and shorter than long pipes 162, after brazing, pipe holding plate 110 to which short pipes 161 are brazed can be easily turned upside down.

[0114] Therefore, in the pipe connection process S50, the short pipe 161 and the long pipe 162 can be connected in a state in which the heavy fin 170 and the long pipe 162 are positioned lower in the direction of gravity than the short pipe 161, i.e., in a state in which their posture is stabilized.

[0115] 10 illustrates a configuration in which the pipe connecting step S50 is performed before the connecting step S40, but the order of the connecting step S40 and the pipe connecting step S50 is arbitrary. That is, the pipe connecting step S50 may be performed after the connecting step S40.

[0116] 6 illustrates an example of a procedure in which the fin attachment step S10 is performed before the brazing step S30. The fin attachment step S10 may be performed after the brazing step S30. A specific example of this procedure will be described below.

[0117] 12 shows a flowchart of the piping structure manufacturing method according to the present embodiment. The preparation step S20 and the connection step S40 are the same as those in any of the first to third embodiments. This embodiment differs from the first embodiment in that a fin attachment step S10 is provided after the brazing step S30.

[0118] 13 is a conceptual diagram for explaining the piping structure manufacturing method according to the present embodiment. Hereinafter, the explanation will be continued along with FIG. 12 while still referring to FIG.

[0119] In brazing step S30 according to the present embodiment, long pipe 163 is brazed to pipe holding plate 110. Long pipe 163 according to the present embodiment is formed straight and has a length sufficient to allow fin 170 to be attached. Note that long pipe 163 is an example of a pipe brazed to pipe holding plate 110.

[0120] That is, the configuration of the pipe holding plate 110 is the same as that shown in FIGS. 7 to 9, but the pipe 160 shown in FIGS.

[0121] Next, in the fin attachment process S10 according to this embodiment, a fin 170 is attached to the portion of the long pipe 163 extending from the second surface 112 in a direction from the first surface 111 toward the second surface 112 (hereinafter referred to as the fin attachment portion).

[0122] The fins 170 can be attached by a known method, specifically, by inserting the fin attachment portion of the long pipe 163 into the fins 170 and then performing pipe expansion processing to expand the outer diameter of the cross section of the fin attachment portion.

[0123] The fin mounting step S10 according to this embodiment also includes a step of connecting other piping to the ends of the fin mounting portions to which the fins 170 are fixed. Specifically, the fin mounting step S10 according to this embodiment includes a step of connecting U-shaped bend piping 164 to the ends of a pair of fin mounting portions to which the fins 170 are respectively fixed.

[0124] One end of the bend pipe 164 is connected to an end of one of the fin mounting portions, and the other end of the bend pipe 164 is connected to an end of the other fin mounting portion. The connection between the bend pipe 164 and the pair of fin mounting portions can be realized by a known method, specifically, brazing.

[0125] Thereafter, in a connecting step S40, the opposing member 120 is connected to the pipe holding plate 110 to which the long pipe 163 is brazed, via the elastic seal member 130.

[0126] As described above, in this embodiment, as in the fourth embodiment, when brazing is performed in the brazing step S30, the fins 170 are not attached to the long pipe 163. Therefore, even when a furnace brazing method is used, it is not necessary to place the fins 170 in the heating furnace. Furthermore, even when a local brazing method is used, the fins 170 do not get in the way. Furthermore, the order of inserting the long pipe 163 into the through hole 113 and placing the ring-shaped molten brazing material 180 can be set arbitrarily.

[0127] Furthermore, in the brazing step S30, each long pipe 163 is independent from the other long pipes 163, so that the long pipes 163 can be easily inserted into the through holes 113. Other configurations and effects are the same as those of the first to third embodiments.

[0128] 14 , protrusions 169 that protrude radially outward may be formed on the outer peripheral surface of pipe 160. Protrusions 169 are formed on the outer peripheral surface of a portion of pipe 160 that extends from first surface 111 in a direction from second surface 112 toward first surface 111. A plurality of protrusions 169 are distributed discretely in the circumferential direction on the outer peripheral surface of pipe 160. Each of protrusions 169 abuts against the edge of the opening of through hole 113 in first surface 111.

[0129] When such a protrusion 169 is formed on the pipe 160, in the soldering process S30 shown in Figure 6, the load of the pipe holding plate 110 acts on the protrusion 169, so that the melting brazing material 180 can be melted while the pipe holding plate 110 is supported by the pipe 160.

[0130] Pipe holding plate 110 is supported by pipe 160 in an orientation in which second surface 112 is positioned higher in the direction of gravity than first surface 111. Therefore, a support jig for maintaining the orientation of pipe holding plate 110 during brazing is not required.

[0131] As shown in Figure 15, when pipe holding plate 110 has peripheral banks 115, each protrusion 169 comes into contact with the edge of the opening of through hole 113 at top 115a of peripheral bank 115. Even in this case, pipe holding plate 110 can be supported by pipe 160 in brazing step S30 shown in Figure 6, so a supporting jig is not required. Note that protrusions 169 shown in Figures 14 and 15 remain as they are after brazing.

[0132] The above-described configuration in which protrusions 169 are provided can also be applied to embodiment 4. That is, pipe 160 shown in Figures 14 and 15 may be short pipe 161 shown in Figure 11. In this case, too, pipe holding plate 110 can be supported by short pipe 161 having protrusions 169 in brazing step S30 shown in Figure 10, eliminating the need for a support jig.

[0133] The configuration in which protrusions 169 are provided can also be applied to embodiment 5. That is, pipe 160 shown in Figures 14 and 15 may be long pipe 163 shown in Figure 13. In this case, too, pipe holding plate 110 can be supported by long pipe 163 having protrusions 169 in brazing step S30 shown in Figure 12, so that a support jig is not required.

[0134] The embodiment has been described above, but the following modifications are also possible.

[0135] 7, 8, 9, 14, and 15 show an example of a configuration in which a ring-shaped molten brazing filler metal 180 is arranged in the circumferential groove 114a. However, the shape of the molten brazing filler metal 180 arranged in the circumferential groove 114a is not particularly limited to a ring shape as long as it fits into the circumferential groove 114a. As an example, the molten brazing filler metal 180 may be formed in an arc shape that fits into the circumferential groove 114a.

[0136] Furthermore, in the brazing step S30, the manner in which the molten brazing material 180 is supplied to the circumferential groove 114a is not limited to the method of placing the molten brazing material 180 in the circumferential groove 114a. As another manner in which the molten brazing material 180 is supplied to the circumferential groove 114a, an operator may melt the tip of a rod-shaped molten brazing material 180 held by hand while bringing the tip close to the circumferential groove 114a.

[0137] 7 to 9, 14, and 15 show examples of the pipe holding plate 110 in which the second surface 112 is located higher in the direction of gravity than the first surface 111 and the second surface 112 and the first surface 111 are held in a horizontal position. Brazing may be performed in a position in which the second surface 112 is located higher in the direction of gravity than the first surface 111 and the second surface 112 and the first surface 111 are inclined with respect to the horizontal plane. Brazing may also be performed in a position in which the second surface 112 and the first surface 111 are held vertically.

[0138] FIG. 2 illustrates a piping structure 100 including fins 170. In embodiments 1-6, the term "fin 170" refers to an assembly of metal plates (hereinafter referred to as "fin plates"). That is, as shown in FIGS. 3, 5, 11, and 13, the fin 170 is configured by arranging multiple fin plates parallel to one another. Each of the multiple pipes 160 shown in FIG. 5, the multiple long pipes 162 shown in FIG. 11, and the multiple long pipes 163 shown in FIG. 13 penetrates multiple fin plates that constitute the fin 170. The internal air described above passes between the fin plates. However, the fin 170 is not limited to an assembly of fin plates. The fin 170 may be configured by one or multiple corrugated fins.

[0139] Furthermore, the fins 170 are not essential. That is, the piping structure 100 may have a configuration without the fins 170. In that case, the fin attachment step S10 shown in Fig. 6 and Fig. 10 is omitted. Also, in the fin attachment step S10 shown in Fig. 12, the attachment of the fins 170 is omitted, and the bent pipes 164 are attached to the pair of long pipes 163.

[0140] The present disclosure allows various embodiments and modifications without departing from the broad spirit and scope of the present disclosure. The above-described embodiments are intended to explain the present disclosure and do not limit the scope of the present disclosure. The scope of the present disclosure is defined by the claims, not the embodiments. Various modifications made within the scope of the claims and the meaning of the disclosure equivalent thereto are considered to be within the scope of the present disclosure.

[0141] This application is based on Japanese Patent Application No. 2024-016973, filed on February 7, 2024. The entire specification, claims, and drawings of Japanese Patent Application No. 2024-016973 are incorporated herein by reference.

[0142] 100 Piping structure, 110 Piping holding plate (plate-shaped portion, pipe holding member), 111 First surface, 111a Sealing location, 112 Second surface, 113 Through hole, 114 Depression portion, 114a Circumferential groove, 115 Circumferential bank, 115a Top portion, 115b Outer circumferential surface, 120 Opposing member, 130 Elastic sealing member, 140 Screw, 150 Header, 151 Inlet, 152 Outlet, 160 Piping, 161 Short pipe (piping), 162 Long pipe, 162a Joint portion, 163 Long pipe (piping), 164 Bend pipe, 169 Protrusion, 170 Fin, 180 Melting brazing filler metal (brazing filler metal), 181 Brazing filler metal, 200 Indoor heat exchanger (heat exchanger), 300 Air conditioning device, 300a Indoor unit for air conditioner, 300b outdoor unit for air conditioner, 300c relay unit for air conditioner, 310 refrigerant closed circuit, 311 compressor, 312 outdoor heat exchanger, 313 expander, 314 relay heat exchanger, 315 gas-liquid separator, 316 four-way valve, 320 heat medium closed circuit, 321 temperature adjustment unit, 322 relay piping, 323 pump, 330 outdoor fan, 340 indoor fan.

Claims

1. A method for manufacturing a metal pipe holding member, comprising: a preparation step of preparing a metal pipe holding member having a plate-shaped portion formed in a plate shape with a first surface and a second surface opposite the first surface in a thickness direction, the plate-shaped portion having a through hole formed in the plate-shaped portion that penetrates the thickness direction and opens to the first surface and the second surface; a brazing step of brazing a metal pipe to an inner surface of the through hole in a state where the metal pipe is inserted into the through hole of the pipe holding member; and a connecting step of connecting an opposing member that is opposed to the first surface to the pipe holding member, wherein the preparation step includes preparing the pipe holding member having a recess formed in the second surface that communicates with the through hole, the recess defining a circumferential groove surrounding the pipe between the second surface and the outer peripheral surface of the pipe inserted into the through hole; and the brazing step includes supplying brazing material to the circumferential groove of the plate-shaped portion with the pipe inserted into the through hole, and melting the supplied brazing material to braze the outer peripheral surface of the pipe to the plate-shaped portion, In the connecting step, the opposing member is connected to the piping holding member having the piping brazed to the plate-like portion by sandwiching an elastic seal member that is elastically compressed by the first surface of the piping holding member and the opposing member while surrounding the piping.

2. A piping structure manufacturing method as described in claim 1, wherein in the preparation step, the piping holding member is prepared, the piping holding member having a circumferential bank formed on the first surface, the circumferential bank protruding in a direction from the second surface toward the first surface in the thickness direction, the circumferential bank defining at least a portion of the through hole in the thickness direction, and surrounding the piping inserted into the through hole, and in the connecting step, the opposing member is connected to the piping holding member by sandwiching the elastic sealing member surrounding the circumferential bank.

3. A piping structure manufacturing method according to claim 1 or 2, wherein in the brazing step, the brazing material having a shape that fits into the circumferential groove is placed in the circumferential groove, and the brazing material is melted in the circumferential groove.

4. A piping structure manufacturing method according to any one of claims 1 to 3, wherein in the brazing process, the brazing material is melted while the piping holding member is held in an orientation in which the second surface is positioned higher in the direction of gravity than the first surface.

5. A piping structure manufacturing method as described in claim 4, wherein a protrusion is formed on the outer peripheral surface of a portion of the piping that extends from the first surface in a direction from the second surface toward the first surface, and in the brazing process, the load of the piping holding member acts on the protrusion that is in contact with the edge of the opening of the through hole, thereby melting the brazing material while the piping holding member is supported by the piping.

6. A piping structure manufacturing method according to any one of claims 1 to 5, further comprising a piping connection step, after the brazing step and before or after the connecting step, of joining a long piping longer than the piping and having fins attached thereto to an end of the portion of the piping extending from the second surface in a direction from the first surface towards the second surface.

7. A piping structure manufacturing method according to any one of claims 1 to 5, further comprising a fin attachment step, after the brazing step and before or after the connecting step, of attaching fins to a portion of the piping extending from the second surface in a direction from the first surface towards the second surface.

8. A piping structure comprising: a metal pipe holding member having a plate-like portion formed in a plate shape having a first surface and a second surface opposite the first surface in a thickness direction, the plate-like portion having a through hole formed in the plate-like portion that penetrates in the thickness direction and opens to the first surface and the second surface; a metal pipe being inserted into the through hole and brazed to the inner surface of the through hole; and an opposing member connected to the pipe holding member in a state facing the first surface, wherein the second surface has a recessed portion that communicates with the through hole and defines a circumferential groove surrounding the pipe between it and the outer peripheral surface of the pipe inserted into the through hole, and an elastic sealing member is interposed between the opposing member and the first surface and surrounds the pipe in a state where it is elastically compressed by the opposing member and the first surface.

9. A piping structure as described in claim 8, wherein a peripheral bank is formed on the first surface, protruding in a direction from the second surface toward the first surface in the thickness direction, the peripheral bank defining at least a portion of the through hole in the thickness direction and surrounding the piping inserted into the through hole, and the elastic sealing member surrounding the peripheral bank.

10. A piping structure as described in claim 8 or 9, wherein the piping comprises: a short pipe brazed to the inner surface of the through hole of the plate-shaped portion; a long pipe longer than the short pipe; and a joint portion connecting the long pipe to the end of the short pipe that extends from the second surface in a direction from the first surface toward the second surface.

11. A piping structure according to any one of claims 8 to 10, wherein a protrusion that abuts against the edge of the opening of the through hole is formed on the outer peripheral surface of the portion of the piping that extends from the first surface in a direction from the second surface toward the first surface.

12. A heat exchanger comprising the piping structure according to any one of claims 8 to 11, wherein a heat medium fluid flows through the piping.

13. The heat exchanger according to claim 12, further comprising: fins attached to a portion of the piping extending from the second surface in a direction from the first surface toward the second surface.

14. An indoor unit for an air conditioner, comprising: an indoor heat exchanger constructed using the heat exchanger according to claim 12 or 13; and an indoor fan for passing air from a space to be air-conditioned through the indoor heat exchanger.

Images