Heat exchanger

Abstract

To fix a plurality of heat transfer pipes to a plate laminated body while restraining remelting of brazed parts included in the plate laminated body.SOLUTION: A heat exchanger comprises: a heat exchange part (40A) comprising fins (41) and a plurality of heat transfer pipes (42); and a plate laminated body (50) constituted in such a manner that a plurality of plates (521-525) are laminated in a lamination direction and brazed to one another, internally comprising refrigerant flow passages (51) communicating with the heat transfer pipes (42), and connected to the heat transfer pipes (42). The heat transfer pipes (42) are connected to the plate laminated body (50) via fixing parts (70, 270, 370, and 470) for fixing the heat transfer pipes (42) to the plate laminated body (50) so as to restrain movement in a first direction that is an axial direction of the heat transfer pipes (42). The fixing parts (70, 270, 370, and 470) are not melted and solidified parts.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present disclosure relates to a heat exchanger. [Background technology]

[0002] Patent Document 1 discloses a refrigerant flow divider for use in an air conditioner. The refrigerant flow divider includes an underplate having a plurality of flow paths formed therein and an overplate laminated on the underplate. The overplate has burring holes to which connecting pipes are connected. It is disclosed that brazing the underplate and the overplate and brazing the connecting pipes to the burring holes are performed simultaneously in a heat treatment furnace. In Patent Document 1, the connecting pipes are connected to heat transfer pipes of a heat exchanger.

[0003] Patent Document 2 discloses a plate heat exchanger. The plate heat exchanger includes a set of frames that sandwich a plurality of heat exchange plates, a fluid nozzle attached to the fluid inlet / outlet portion of the frame, and a connection pipe connected to the fluid nozzle. A male thread is machined on the outer periphery of the connection pipe. A female thread is machined on the inner periphery of the fluid nozzle to be connected to the male thread of the connection pipe. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-220914 [Patent Document 2] Japanese Utility Model Application Publication No. 4-115287 Summary of the Invention [Problem to be solved by the invention]

[0005] The plate stack described in Patent Document 1 and the heat transfer tubes of the heat exchanger are generally connected by brazing. Brazing of the plate stack and the heat transfer tubes can be performed in a heat treatment furnace, as described in Patent Document 1. When brazing the plate stack and the heat transfer tubes in a heat treatment furnace, the heat exchanger including the fins and the plate stack are placed together in the heat treatment furnace.

[0006] Generally, the fins of a heat exchanger are subjected to various surface treatments, and if the fins are exposed to high temperatures in a heat treatment furnace, the surface treatments applied to the fins may be adversely affected.

[0007] To minimize the impact on the surface treatment of the fins, it is conceivable to braze the plate stack and the heat transfer tubes using burner brazing. However, there is a risk that the heat from the burner will also heat the plates. If the plates are heated, there is a risk that the brazing material that joins the plates together will remelt. If the brazing material remelts, there is a risk that the plates will become misaligned or that the remelted brazing material will narrow the refrigerant flow path.

[0008] A method of screwing the heat transfer tubes, as described in Patent Document 2, is also conceivable. However, when screwing the heat transfer tubes, it is not possible to connect multiple heat transfer tubes together to the plate stack. This method cannot be used for heat exchangers that have a heat exchange section that includes fins and multiple heat transfer tubes.

[0009] An object of the present disclosure is to fix a plurality of heat transfer tubes to a plate stack while suppressing remelting of the brazing material between the plates. [Means for solving the problem]

[0010] The first aspect relates to a heat exchanger, and the heat exchanger (40) includes a heat exchange section (40A) having fins (41) and a plurality of heat transfer tubes (42), and a plate stack (50) configured by stacking a plurality of plates (521 to 525) in a stacking direction and brazing them to each other, the plate stack (50) having refrigerant flow paths (51, 61) communicating with the heat transfer tubes (42) therein, the heat transfer tubes (42) being connected to the plate stack (50) via fixing parts (70, 270, 370, 470) that fix the heat transfer tubes (42) to the plate stack (50) so as to suppress movement of the heat transfer tubes (42) in a first direction that is an axial direction of the heat transfer tubes (42), and the fixing parts (70, 270, 370, 470) are not melt-solidified parts.

[0011] In the first aspect, since the multiple plates (521-525) are brazed together, if the fixing portions (70, 270, 370, 470) are melt-solidified portions made of brazing material or the like, there is a risk that the brazing material between the plates (521-525) will re-melt when connecting the plate stack (50) and the heat transfer tubes (42). In the first aspect, since the fixing portions (70, 270, 370, 470) are not melt-solidified portions, the multiple heat transfer tubes (42) can be fixed to the plate stack (50) while suppressing re-melting of the brazing material between the plates (521-525).

[0012] In the second aspect, in the first aspect, the fixing portion (70, 270) includes a radial pressing member (71, 271) that presses the heat transfer tube (42) from the radial outside toward the radial inside, and a holding member (72) that is attached to the plate (521) and sandwiches the radial pressing member (71, 271) in the stacking direction.

[0013] In the second aspect, by pressing the heat transfer tube (42) in the radial direction, it is possible to suppress the movement of the heat transfer tube (42) in the first direction and to suppress the wobbling of the heat transfer tube (42) in the radial direction.

[0014] In a third aspect, in the second aspect, the radial pressing member (71) is an annular elastic member disposed around the heat transfer tube (42).

[0015] In the third aspect, the radial pressing member (71) can radially press the heat transfer tube (42) by its own elastic force, thereby fixing the heat transfer tube (42) to the plate stack (50) with a simple structure.

[0016] The fourth aspect is the third aspect, wherein at least one of the plate (521) or the retaining member (72) has a ring-shaped accommodating portion (53a) in which the elastic member is accommodated, and the maximum width of the accommodating portion (53a) as viewed from the first direction is smaller than the outer diameter of the elastic member before it is accommodated in the accommodating portion (53a).

[0017] In the fourth aspect, when the elastic member is accommodated in the accommodation portion (53a), the elastic member is compressed radially inward, so that the inner circumferential surface of the accommodation portion (53a) and the elastic member are securely in contact with each other. Friction is generated between the heat transfer tube (42) and the elastic member, and friction is also generated between the inner circumferential surface of the accommodation portion (53a) and the elastic member, so that movement of the heat transfer tube (42) in the first direction (D1) can be suppressed. Furthermore, the radial pressing member (71) fills the gap between the inner circumferential surface of the accommodation portion (53a) and the heat transfer tube (42), so that wobbling of the heat transfer tube (42) in the radial direction can be suppressed.

[0018] In a fifth aspect, in the second aspect, the radial pressing member (271) is a ring member (271) having a leaf spring (271a) biased radially inward and toward the heat exchange unit (40A) in the first direction.

[0019] In the fifth aspect, when an attempt is made to move the heat transfer tube (42) toward the heat exchange section (40A), the plate spring (271a) catches the heat transfer tube (42) and prevents the tube from moving. This makes it possible to fix the heat transfer tube (42) to the plate stack (50) with a simple structure.

[0020] In a sixth aspect, in the fifth aspect, a seal member (280) is disposed between the plate (521) and the ring member (271).

[0021] In the sixth aspect, the movement of the heat transfer tube (42) in the first direction (D1) can be suppressed, and the sealing performance of the refrigerant flow path (51) can be ensured.

[0022] In the seventh aspect, in the first aspect, the fixing portion (370) has a protrusion (371) protruding radially outward from the side portion of the heat transfer tube (42), and a holding member (72) attached to the plate (521) and sandwiching the protrusion (371) in the stacking direction.

[0023] In the seventh aspect, when the heat transfer tube (42) is moved in the first direction (D1), the protrusions (371) are caught on the holding member (72) and the plate (521), thereby suppressing the movement of the heat transfer tube (42). The heat transfer tube (42) can be fixed to the plate stack (50) with a simple configuration.

[0024] In an eighth aspect, in the seventh aspect, the protrusion (371) is an expanded diameter portion (42a) formed by expanding the diameter of a part of the heat transfer tube (42) radially outward.

[0025] In the eighth aspect, the heat transfer tubes (42) can be fixed to the plate stack (50) without using any other members.

[0026] A ninth aspect is the seventh or eighth aspect, wherein the protrusion (371) has a flat surface (371a) that comes into contact with the plate (521).

[0027] In the ninth aspect, the projection (371) and the plate (521) come into surface contact with each other, and therefore, the movement of the heat transfer tube (42) in the first direction (D1) can be effectively suppressed.

[0028] A tenth aspect is any one of the seventh to ninth aspects, wherein a seal member (380) is disposed between the protrusion (371) and the plate (521).

[0029] In the tenth aspect, the movement of the heat transfer tube (42) in the first direction (D1) can be suppressed, and the sealing performance of the refrigerant flow path (51) can be ensured.

[0030] An eleventh aspect is any one of the second to tenth aspects, wherein the holding member (72) is a plate-like member.

[0031] In the eleventh aspect, even when a plurality of heat transfer tubes (42) are provided, the heat transfer tubes (42) can be collectively fixed to the plate stack (50) by one holding member (72).

[0032] In a twelfth aspect, in the eleventh aspect, the holding member (72) is made of the same material as the plate (521).

[0033] In the twelfth aspect, even if the holding member (72) and the plate (521) come into contact with each other, electrolytic corrosion is unlikely to occur between the holding member (72) and the plate (521), and therefore the heat transfer tube (42) can be maintained fixed to the plate stack (50) for a long period of time.

[0034] A thirteenth aspect is the eleventh or twelfth aspect, wherein the thickness of the holding member (72) in the first direction is thinner than the thickness of the plate (521).

[0035] In the thirteenth aspect, even if the holding member (72) is provided, the length of the heat exchanger (40) can be prevented from increasing. Therefore, the heat exchanger (40) can be made compact while the heat transfer tubes (42) are fixed to the plate stack (50).

[0036] A fourteenth aspect is any one of the eleventh to thirteenth aspects, wherein the holding member (72) is fixed to the plate (521) with screws.

[0037] In the fourteenth aspect, the fixed state between the holding member (72) and the plate (521) can be easily maintained with a simple configuration, and therefore the fixed state of the heat transfer tube (42) can be maintained for a long period of time.

[0038] A fifteenth aspect is any one of the eleventh to thirteenth aspects, wherein the holding member (72) is adhered to the plate (521) with an adhesive.

[0039] In the fifteenth aspect, the holding member (72) and the plate (521) are not in direct contact with each other, which makes it difficult for electrolytic corrosion to occur, and therefore the heat transfer tube (42) can be kept fixed for a long period of time.

[0040] A sixteenth aspect is any one of the second to fifteenth aspects, wherein the shortest distance (L) between the fin (41) and the holding member (72) is 30 mm or less.

[0041] In the sixteenth aspect, even if the holding member (72) is provided, the length of the heat exchanger (40) can be prevented from increasing. Therefore, the heat exchanger (40) can be made compact while the heat transfer tubes (42) are fixed to the plate stack (50).

[0042] In a seventeenth aspect, in the first aspect, the fixing portion (470) is an adhesive.

[0043] In the seventeenth embodiment, the heat transfer tube (42) can be easily fixed to the plate (521).

[0044] In an 18th aspect, in any one of the 1st to 17th aspects, an end of the heat transfer tube (42) on the plate stack (50) side in the first direction penetrates a first plate (521) of the plurality of plates (521 to 525) that is located closest to the heat exchange unit (40A), and abuts against the plate (522) that is located farther from the heat exchange unit (40A) than the first plate (521).

[0045] In the eighteenth aspect, when connecting the plate stack (50) and the heat transfer tubes (42), it is easy to determine whether the connection is complete. The structure for fixing the heat transfer tubes (42) to the plate stack (50) can be configured with high precision.

[0046] In a nineteenth aspect, in the eighteenth aspect, when the inside of the heat transfer tube (42) is viewed from the heat exchange section (40A) side in the first direction, the inside of the heat transfer tube (42) partially overlaps with the refrigerant flow path (51).

[0047] In the nineteenth aspect, the heat transfer tubes (42) can be fixed to the plate stack (50) without narrowing the refrigerant flow path (51). [Brief explanation of the drawings]

[0048] [Figure 1] FIG. 1 is a piping diagram of an air conditioner having a heat exchanger according to the first embodiment. [Figure 2] FIG. 2 is a front view of the air conditioning indoor unit. [Figure 3] FIG. 3 is a cross-sectional view of the air conditioning indoor unit taken along line II-II. [Figure 4] FIG. 4 is a front view showing the internal structure of the air conditioning indoor unit. [Figure 5] FIG. 5 is a plan view showing the heat exchanger. [Figure 6] FIG. 6 is a view of the plate stack from the left side. [Figure 7] FIG. 7 is a cross-sectional view illustrating a coolant flow path of the plate stack. [Figure 8] FIG. 8 is a cross-sectional view showing a state in which the heat transfer tube and the first front plate are connected to each other. [Figure 9] FIG. 9 is a cross-sectional view corresponding to line IX-IX in FIG. [Figure 10] FIG. 10 is a cross-sectional view showing the process of connecting the heat transfer tube and the first front plate, showing the state before the O-ring is inserted into the receiving portion. [Figure 11]FIG. 11 is a cross-sectional view showing the process of connecting the heat transfer tube and the first front plate, showing a state in which the O-ring has been inserted into the receiving portion. [Figure 12] FIG. 12 is a cross-sectional view showing a process of connecting the heat transfer tube and the first front plate, showing a state in which the holding member is disposed on the first front plate. [Figure 13] FIG. 13 is a cross-sectional view showing a connection state between a heat transfer tube and a front connection portion in a heat exchanger according to the second embodiment. [Figure 14] FIG. 14 is an enlarged view of a portion XIV in FIG. [Figure 15] FIG. 15 is a cross-sectional view taken along line XV-XV in FIG. [Figure 16] FIG. 16 is a cross-sectional view showing a connection state between a heat transfer tube and a front connection part in a heat exchanger according to the third embodiment. [Figure 17] FIG. 17 is an enlarged view of part XVII in FIG. [Figure 18] FIG. 18 is a cross-sectional view taken along line XVIII-XVIII in FIG. [Figure 19] FIG. 19 is a cross-sectional view showing a connection state between a heat transfer tube and a front connection portion in a heat exchanger according to the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0049] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the embodiments shown below, and various modifications are possible within the scope of the technical concept of the present disclosure. Since the drawings are intended to conceptually explain the present disclosure, dimensions, ratios, or numbers may be exaggerated or simplified as necessary to facilitate understanding.

[0050] First Embodiment (1) Overall configuration of the air conditioning unit The first embodiment is an air conditioner (10) equipped with a heat exchanger. The air conditioner (10) adjusts the temperature of air in an indoor space (I) which is a target space.

[0051] As shown in Fig. 1, the air conditioner (10) is an example of a refrigeration cycle device including a refrigerant circuit (11). The refrigerant circuit (11) is filled with a refrigerant. The refrigerant circuit (11) performs a refrigeration cycle by circulating the refrigerant.

[0052] The air conditioner (10) includes an outdoor unit (20), an indoor unit (30), a first connecting pipe (12), and a second connecting pipe (13). The air conditioner (10) is a pair type having one outdoor unit (20) and one indoor unit (30). The first connecting pipe (12) is a gas connecting pipe, and the second connecting pipe (13) is a liquid connecting pipe.

[0053] The outdoor unit (20) is installed outdoors and includes an outdoor casing (20a), and a compressor (21), an outdoor heat exchanger (22), an outdoor expansion valve (23), a four-way selector valve (24), and an outdoor fan (25) housed in the outdoor casing (20a).

[0054] The compressor (21) is a rotary compressor such as a swing piston type, rotary type, or scroll type. The outdoor heat exchanger (22) exchanges heat between the refrigerant and outdoor air. The outdoor heat exchanger (22) is a fin-and-tube type. The outdoor expansion valve (23) reduces the pressure of the refrigerant. The outdoor expansion valve (23) is an electronic expansion valve. The four-way selector valve (24) switches between a first state (a state indicated by a solid line in FIG. 1 ) and a second state (a state indicated by a dashed line in FIG. 1 ). In the first state, the four-way selector valve (24) connects the discharge port of the compressor (21) to the gas end of the outdoor heat exchanger (22) and connects the suction port of the compressor (21) to the first connecting pipe (12). The four-way selector valve (24) in the second state communicates the discharge port of the compressor (21) with the first connecting pipe (12) and also communicates the suction port of the compressor (21) with the gas end of the outdoor heat exchanger (22). The outdoor fan (25) transports the air flowing through the outdoor heat exchanger (22). The outdoor fan (25) is a propeller fan.

[0055] The indoor unit (30) includes a casing (31), and a heat exchanger unit (U) and an indoor fan (32) housed in the casing (31).

[0056] (2) Air conditioning indoor unit The indoor unit (30) serving as an indoor air conditioner will be described in detail with reference to Figures 2 to 4. The indoor unit (30) of the first embodiment is a wall-mounted type installed on a wall of the indoor space (I). In the following description, the terms "upper," "lower," "right," "left," "front," and "rear" correspond to the directions of the arrows shown in Figures 2 and 3, and the left-right direction is based on the case where the indoor casing (31) is viewed from the front.

[0057] (2-1) Casing 2 and 3, the casing (31) is formed in the shape of a horizontally long box and includes a front plate (31a), a rear plate (31b), an upper plate (31c), a lower plate (31d), a first side plate (31e), and a second side plate (31f).

[0058] The front plate (31a) is formed on the front side of the casing (31) and constitutes the front surface of the casing (31). The rear plate (31b) is formed on the rear side of the casing (31) and constitutes the rear surface of the casing (31). The upper plate (31c) is formed on the upper side of the casing (31) and constitutes the upper surface of the casing (31). The lower plate (31d) is formed on the lower side of the casing (31) and constitutes the lower surface of the casing (31). The first side plate (31e) is formed on the right side of the casing (31) and constitutes the right surface of the casing (31). The second side plate (31f) is formed on the left side of the casing (31) and constitutes the left surface of the casing (31).

[0059] An air inlet (33) is formed in the upper plate (31c), and an air outlet (34) is formed in the lower plate (31d). An air passage (P) is formed inside the casing (31) from the air inlet (33) to the air outlet (34). The air inlet (33) extends in the longitudinal direction of the casing (31). The air inlet (33) is an opening for taking air from the indoor space (I) into the air passage (P). An air outlet (34) is formed in the lower plate (31d). The air outlet (34) extends in the longitudinal direction of the casing (31). The air outlet (34) is an opening for blowing air from the air passage (P) into the indoor space (I).

[0060] (2-2) Filter The indoor unit (30) includes a filter (35). The filter (35) is located at the back of the air inlet (33) and upstream of the heat exchanger unit (U). The filter (35) collects dust in the air sent from the air inlet (33) to the heat exchanger unit (U). The indoor unit (30) may include a dust removal mechanism that removes the dust collected by the filter (35).

[0061] (2-3) Heat exchanger unit The heat exchanger unit (U) includes one indoor heat exchanger (40) and one indoor expansion valve (37). The indoor heat exchanger (40) includes one heat exchanger body (B) and two plate stacks (50, 60). The heat exchanger body (B) of the indoor heat exchanger (40) is disposed so as to cross the air passage (P). The air passage (P) is divided into an upstream side and a downstream side of the heat exchanger body (B).

[0062] (2-4) Indoor fan The indoor fan (32) is disposed in the air passage (P). The indoor fan (32) is disposed in the air passage (P) downstream of the indoor heat exchanger (40). The indoor fan (32) is a cross-flow fan. The fan rotor of the indoor fan (32) extends in the longitudinal direction of the casing (31).

[0063] (2-5) Flap The indoor unit (30) has a flap (36) that adjusts the direction of air blown out from the air outlet (34). The flap (36) adjusts the air direction in the vertical direction. The indoor unit (30) may have multiple flaps (36). The flap (36) may adjust the air direction in the horizontal direction.

[0064] (3) Indoor heat exchanger As described above, the indoor heat exchanger (40) includes the heat exchanger body (B), the plate stack (50, 60), the indoor expansion valve (37), the gas relay pipe (12a), and the liquid relay pipe (13a).

[0065] (3-1) Heat exchanger body The heat exchanger body (B) shown in Figures 3 to 7 is a fin-and-tube heat exchanger having fins (41) and heat transfer tubes (42). The heat exchanger body (B) has a plurality of fins (41) arranged in the longitudinal direction of the casing (31) and a plurality of heat transfer tubes (42) extending in the direction of arrangement of the fins (41). The heat exchanger body (B) exchanges heat between air and a refrigerant.

[0066] The arrangement direction of the fins (41) corresponds to the longitudinal direction (here, the left-right direction) of the casing (31). The fins (41) are rectangular plate-shaped with long and short sides. The thickness direction of the fins (41) corresponds to the arrangement direction of the fins (41). The multiple fins (41) are arranged at predetermined intervals in the thickness direction. This interval defines an air flow path. The fins (41) are made of an aluminum alloy.

[0067] The fins 41 are subjected to a surface treatment to improve surface tension before the heat transfer tubes 42 are inserted through the fins 41.

[0068] The heat transfer tubes (42) are straight tubes. The heat transfer tubes (42) are made of an aluminum alloy. Alternatively, the heat transfer tubes (42) may be made of a copper alloy. A refrigerant flow path is formed inside the heat transfer tubes (42). The heat transfer tubes (42) extend parallel to one another and penetrate the fins (41). One end of each of the heat transfer tubes (42), i.e., a right end, protrudes to the right of the fins (41). One end of each of the heat transfer tubes is connected to the plate stack (50, 60). Of the other ends of the heat transfer tubes (42), i.e., left end portions, of two adjacent heat transfer tubes (42) are connected to each other by a U-shaped tube (48). The two adjacent heat transfer tubes (42) and the U-shaped tube (48) connecting them are formed seamlessly and integrally.

[0069] The heat exchanger body (B) of the first embodiment has a front heat exchange section (40A) which is a first heat exchange section, and a rear heat exchange section (40B) which is a second heat exchange section. The front heat exchange section (40A) is located toward the front of the casing (31), and the rear heat exchange section (40B) is located toward the rear of the casing (31). The front heat exchange section (40A) and the rear heat exchange section (40B) are aligned in a direction perpendicular to both the up-down direction and the first direction (D1) which is the axial direction of the heat transfer tubes (42), i.e., in the front-rear direction, with the indoor fan (32) between them.

[0070] The front heat exchange section (40A) includes a front main heat exchange section (43), a first auxiliary heat exchange section (44), and a second auxiliary heat exchange section (45).

[0071] The front main heat exchange section (43) is disposed in the front heat exchange section (40A) closer to the indoor fan (32). The front main heat exchange section (43) has a V-shaped outer shape when viewed in the longitudinal direction of the heat transfer tubes (42). The tip of the V faces forward.

[0072] The front main heat exchange section (43) is composed of a first front main heat exchange section (43a) extending obliquely upward toward the rear side and a second front main heat exchange section (43b) extending obliquely downward toward the rear side. The first front main heat exchange section (43a) is located at an upper part of the front main heat exchange section (43), and the second front main heat exchange section (43b) is located at a lower part of the front main heat exchange section (43). The lower ends of the first front main heat exchange section (43a), i.e., the lower short sides of the fins (41), are in contact with the long sides of the fins (41) of the second front main heat exchange section (43b) (strictly speaking, the upper end portions of the long sides of the fins (41)). The angle between the rear long side of the first front main heat exchange section (43a) and the upper long side (the side closer to the first front main heat exchange section (43a)) of the second front main heat exchange section (43b) is approximately 90° to 110°. The fins (41) constituting the first front main heat exchange section (43a) and the fins (41) constituting the second front main heat exchange section (43b) may be integrally formed or may be separate.

[0073] The first auxiliary heat exchange section (44) is provided on the inlet side (front side) of the first front main heat exchange section (43a). The lengths of the long and short sides of the fins (41) of the first auxiliary heat exchange section (44) are shorter than the lengths of the long and short sides of the fins (41) of the first front main heat exchange section (43a).

[0074] The second auxiliary heat exchange section (45) is provided on the inlet side (front side) of the second front main heat exchange section (43b). The lengths of the long and short sides of the fins (41) of the second auxiliary heat exchange section (45) are shorter than the lengths of the long and short sides of the fins (41) of the second front main heat exchange section (43b).

[0075] The rear heat exchange section (40B) has a rear main heat exchange section (46) and a third auxiliary heat exchange section (47). The rear main heat exchange section (46) is disposed closer to the indoor fan (32) in the rear heat exchange section (40B).

[0076] The third auxiliary heat exchange section (47) is provided on the inlet side (rear side) of the rear main heat exchange section (46). The lengths of the long sides and short sides of the fins (41) of the third auxiliary heat exchange section (47) are shorter than the lengths of the long sides and short sides of the fins (41) of the rear main heat exchange section (46). The number of rows and columns of the heat transfer tubes (42) of the third auxiliary heat exchange section (47) is fewer than the number of rows and columns of the heat transfer tubes (42) of the rear main heat exchange section (46).

[0077] The plate stack (50, 60) is disposed to the right of the rightmost fin (41) and parallel to the fin (41). The plate stack (50, 60) is connected to one end of the heat transfer tube (42). As shown in FIG. 5, the plate stack (50, 60) includes a front plate stack (50) connected to the heat transfer tube (42) of the front heat exchange section (40A) and a rear plate stack (60) connected to the heat transfer tube (42) of the rear heat exchange section (40B). The front plate stack (50) is disposed so as to overlap the front heat exchange section (40A) in the first direction (D1). The rear plate stack (60) is disposed so as to overlap the rear heat exchange section (40B) in the first direction (D1). The plate stacks (50, 60) have therein refrigerant flow paths (51, 61) that communicate with the heat transfer tubes (42). The front plate stack (50), the rear plate stack (60), and the connection structure between the heat transfer tubes (42) and the plate stacks (50, 60) will be described in detail later.

[0078] (3-2) Indoor expansion valve, gas relay pipe, liquid relay pipe The indoor expansion valve (37) is an electronic expansion valve with a variable opening. As shown in Fig. 5, the indoor expansion valve (37) is disposed on the right side of the plate stacks (50, 60). The indoor expansion valve (37) is connected to the front plate stack (50) via a first internal pipe (38) and to the rear plate stack (60) via a second internal pipe (39). The first internal pipe (38) and the second internal pipe (39) are examples of refrigerant pipes that connect the refrigerant flow path (51) of the front plate stack (50) and the refrigerant flow path (61) of the rear plate stack (60).

[0079] One end of the gas relay pipe (12a) is connected to the rear plate stack (60). The other end of the gas relay pipe (12a) is connected to the first connecting pipe (12) via a joint. One end of the liquid relay pipe (13a) is connected to the front plate stack (50). The other end of the liquid relay pipe (13a) is connected to the second connecting pipe (13) via a joint.

[0080] (4) Plate stack The plate stack (50, 60) will be described in detail with reference to FIGS.

[0081] (4-1) Front plate stack The front plate stack (50) includes a front main body portion (52) having a refrigerant flow path (51) therein, a plurality of front insertion portions (53) that communicate with the refrigerant flow path (51) and into which a plurality of heat transfer tubes (42) of the front heat exchange portion (40A) are inserted, a front relay portion (54) to which the first internal piping (38) is connected, and a liquid end portion (55) that communicates with the second connection piping (13) via a liquid relay pipe (13a).

[0082] (4-1-1) Front main body part As shown in FIG. 5 , the front main body portion (52) is a thick plate-like member formed by stacking five front plates. The stacking direction of the front plates is the same as the first direction (D1). In the front plate stack (50), a first front plate (521), a second front plate (522), a third front plate (523), a fourth front plate (524), and a fifth front plate (525) are stacked in order from the front heat exchange section (40A). The second front plate (522), the third front plate (523), and the fourth front plate (524) are intermediate plates sandwiched between the first front plate (521) and the fifth front plate (525). The five front plates are flat plate-like members having the same outer edge shape. In the first embodiment, the front plates are made of an aluminum alloy. The material of each of the front plates (521-525) is not limited to aluminum alloy, and may be, for example, copper alloy or stainless steel. The thickness of the first front plate (521), second front plate (522), third front plate (523), fourth front plate (524), and fifth front plate (525) is, for example, 3.0 mm. The front plates are joined to each other by furnace brazing. Note that the number of front plates is just an example, and the number of front plates may be four or less, or six or more. Hereinafter, when there is no need to distinguish between the front plates, they will simply be referred to as front plates.

[0083] The front main body portion (52) has a first left side surface (52a) which is the surface on the front heat exchange section (40A) side (here, the left side) in the stacking direction, a first right side surface (52b) which is the surface opposite the first left side surface (52a) in the stacking direction, and a first peripheral surface (52c) which is the peripheral surface extending across the first left side surface (52a) and the first right side surface (52b). The first left side surface (52a) is the surface of the first front plate (521) which faces the front heat exchange section (40A). The first right side surface (52b) is the surface of the fifth front plate (525) which is opposite the fourth front plate (524). The first peripheral surface (52c) is a surface formed by the side surfaces of the front plates (521-525).

[0084] (4-1-2) Front insertion section 7, the front insertion portion 53 is a round hole that penetrates the first front plate 521 in the stacking direction. The inner diameter of the front insertion portion 53 is the same as or slightly larger than the outer diameter of the heat transfer tube 42.

[0085] No material that melts and solidifies due to heat, such as brazing material, is disposed between the front insertion portion (53) and the heat transfer tube (42).

[0086] (4-1-3) Front relay section, liquid end As shown in Fig. 6, the front relay portion (54) is a circular pipe. The front relay portion (54) is provided on the fifth front plate (525) and disposed on the first right side surface (52b) of the front main body portion (52). In the front plate stack (50), the first internal pipe (38) is connected to the first right side surface (52b) of the front plate stack (50). The front relay portion (54) is joined to an end of the front first internal pipe (38) by brazing.

[0087] The liquid end portion (55) is a circular pipe. The liquid end portion (55) is provided on the fifth front plate (525) and disposed on the first right side surface (52b) of the front main body portion (52). The liquid end portion (55) is joined to the end portion of the liquid relay pipe (13a) by brazing.

[0088] At the position of the liquid end portion 55, the refrigerant flow path 51 of the front plate assembly 50 extends straight in the stacking direction of the front plates without being connected to other refrigerant flow paths 51. The refrigerant flow path 51 at the position of the liquid end portion 55 communicates with the heat transfer tube 42 located lowest in the second auxiliary heat exchange section 45.

[0089] The front relay portion (54) and the liquid end portion (55) are molded seamlessly and integrally with the fifth front plate (525). More specifically, the front relay portion (54), the liquid end portion (55), and the fifth front plate (525) are configured from a single member. The front relay portion (54) and the liquid end portion (55) are molded integrally with the fifth front plate (525) by burring the fifth front plate (525). The front relay portion (54) and the liquid end portion (55) may also be molded integrally with the fifth front plate (525) by casting or sintering metal powder using a 3D printer.

[0090] (4-2) Rear plate laminate The rear plate stack (60) includes a rear main body portion (62) having a refrigerant flow path (61) therein, a plurality of rear insertion portions (63) that communicate with the refrigerant flow path (61) and into which a plurality of heat transfer tubes (42) of the rear heat exchange portion (40B) are inserted, a rear relay portion (64) to which the second internal piping (39) is connected, and a gas end portion (65) that communicates with the first connection piping (12) via the gas relay pipe (12a).

[0091] (4-2-1) Rear body The rear main body portion (62) has basically the same configuration as the front main body portion (52), except for the shape of the outer edges of the plates as viewed in the axial direction of the heat transfer tubes (42) and the internal refrigerant flow paths (61). As shown in FIG. 5, the rear main body portion (62) is a thick plate-like member formed by stacking five rear plates. The stacking direction of the rear plates is the same as the axial direction of the heat transfer tubes (42). In the rear plate stack (60), a first rear plate (621), a second rear plate (622), a third rear plate (623), a fourth rear plate (624), and a fifth rear plate (625) are stacked in order from the side closest to the rear heat exchange section (40B). The second rear plate (622), the third rear plate (623), and the fourth rear plate (624) are intermediate plates sandwiched between the first rear plate (621) and the fifth rear plate (625). In the first embodiment, the rear plates are made of an aluminum alloy. The material of each of the rear plates (621-625) is not limited to an aluminum alloy and may be, for example, a copper alloy or stainless steel. The thickness of the first rear plate (621), the second rear plate (622), the third rear plate (623), the fourth rear plate (624), and the fifth rear plate (625) is, for example, 3.0 mm. The five rear plates are joined to each other by furnace brazing. Note that the number of rear plates is merely an example, and the number may be four or less or six or more. The number of front plates and the number of rear plates may be different. Hereinafter, when there is no need to distinguish between the rear plates, they will simply be referred to as rear plates.

[0092] The rear main body portion (62) has a second left side surface (62a) that is a surface facing the rear heat exchange unit (40B) in the axial direction of the heat transfer tube (42), a second right side surface (62b) that is a surface opposite the second left side surface (62a) in the axial direction, and a second circumferential surface (62c) that is a circumferential surface extending across the second left side surface (62a) and the second right side surface (62b). The second left side surface (62a) is a surface of the first rear plate (621) that faces the rear heat exchange unit (40B). The second left side surface (62a) is a surface of the fifth rear plate (625) that is opposite the fourth rear plate (624). The second circumferential surface (62c) is a surface formed by the side surfaces of the rear plates (621-625).

[0093] (4-2-2) Rear insertion section 7, the rear insertion portion 63 is a round hole that penetrates the first rear plate 621 in the stacking direction. The inner diameter of the rear insertion portion 63 is the same as or slightly larger than the outer diameter of the heat transfer tube 42.

[0094] No material that melts and solidifies due to heat, such as brazing material, is disposed between the rear insertion portion 63 and the heat transfer tube 42 .

[0095] (4-2-3) Rear relay section, gas end The rear relay portion (64) is a circular pipe. As shown in Fig. 6, the rear relay portion (64) is provided on the fifth rear plate (625) and arranged on the second right side surface (62b) of the rear main body portion (62). That is, in the rear plate stack (60), the second internal pipe (39) connecting the refrigerant flow path (51) of the front plate stack (50) and the refrigerant flow path (61) of the rear plate stack (60) is connected to the second right side surface (62b) of the rear plate stack (60).

[0096] The gas end portion (65) is a circular pipe and is provided on the fifth rear plate (625) and disposed on the second right side surface (62b) of the rear main body portion (62).

[0097] The rear relay portion (64) and the gas end portion (65) are molded seamlessly and integrally with the fifth rear plate (625). More specifically, the rear relay portion (64), the gas end portion (65), and the fifth rear plate (625) are configured as a single member. The rear relay portion (64) and the gas end portion (65) are molded integrally with the fifth rear plate (625) by burring the fifth rear plate (625). The rear relay portion (64) and the gas end portion (65) may also be molded integrally with the fifth rear plate (625) by casting or sintering metal powder using a 3D printer.

[0098] (5) Fixed part The heat transfer tubes (42) and the plate stack (50, 60) are connected via fixing portions (70). The fixing portions (70) fix the heat transfer tubes (42) to the plate stack (50, 60) so as to prevent movement in the first direction (D1). The fixing portions (70) are not melt-solidified portions that melt and solidify due to heat. The fixing portions (70) between the heat transfer tubes (42) and the front plate stack (50) will be described in detail below. The fixing portions between the heat transfer tubes (42) and the rear plate stack (60) have the same configuration as the fixing portions (70) between the heat transfer tubes (42) and the front plate stack (50), and therefore will not be described in detail.

[0099] As shown in FIG. 8, the fixing portion (70) includes an O-ring (71) and a holding member (72) attached to the first front plate (521) with the O-ring (71) sandwiched therebetween in the stacking direction.

[0100] The O-ring (71) is an annular elastic member made of rubber or the like. The O-ring (71) is disposed in close contact with the outer periphery of the heat transfer tube (42). In other words, the heat transfer tube (42) is inserted inside the O-ring (71). The inner diameter of the O-ring (71) is smaller than the outer diameter of the heat transfer tube (42) before the heat transfer tube (42) is inserted (see FIG. 10 ), and is equal to the outer diameter of the heat transfer tube (42) after the heat transfer tube (42) is inserted. The O-ring (71) presses the heat transfer tube (42) in the radial direction of the heat transfer tube (42) by its own elastic force. The O-ring (71) is an example of a radial pressing member.

[0101] The O-ring (71) is accommodated in a accommodating portion (53a) formed at the end of the front insertion portion (53) on the heat exchanger body (B) side. As shown in FIG. 9, the accommodating portion (53a) is annular when viewed from the first direction (D1). As shown in FIG. 10, the maximum width of the accommodating portion (53a), i.e., the inner diameter of the accommodating portion (53a), is smaller than the outer diameter of the O-ring (71) before it is accommodated in the accommodating portion (53a). The thickness of the O-ring (71) is greater than the depth of the accommodating portion (53a) from the first left side surface (52a) before the holding member (72) is fixed to the first front plate (521).

[0102] The holding member (72) is a plate member extending parallel to the first front plate (521). The thickness of the holding member (72) in the first direction (D1) is thinner than the thickness of the front plates (521-525) in the first direction (D1). The thickness of the holding member (72) is, for example, 1.5 mm. The holding member (72) is made of the same material as the first front plate (521). The holding member (72) is made of, for example, an aluminum alloy. The material of the holding member (72) may be the same as that of the first front plate (521). When the first front plate (521) is made of a copper alloy, the holding member (72) is made of a copper alloy. The shortest distance (L) in the first direction (D1) between the holding member (72) and the fin (41) closest to the front plate stack (50) is 30 mm or less.

[0103] The holding member 72 has insertion holes 72a through which the heat transfer tubes 42 are inserted. The insertion holes 72a are formed to correspond to the number and arrangement of the heat transfer tubes 42. The inner diameter of the insertion holes 72a is the same as the inner diameter of the front insertion portion 53 and is the same as or slightly larger than the outer diameter of the heat transfer tubes 42.

[0104] The holding member (72) is fixed to the first front plate (521) with screws. The holding member (72) has holes (72b) through which the screws (73) pass, and the first front plate (521) has screw holes (521a) at positions corresponding to the holes (72b). The screw holes (521a) are provided in a plurality of locations on the first front plate (521). The screw holes (521a) do not penetrate the first front plate (521). When fixed to the first front plate (521) with screws, the holding member (72) comes into contact with the first left side surface (52a).

[0105] When the heat transfer tubes (42) are fixed to the front plate assembly (50) by the fixing portions (70), the ends of the heat transfer tubes (42) abut against the second front plate (522). As shown in Fig. 9, the insides of the heat transfer tubes (42) partially overlap the refrigerant flow paths (51) when viewed from the heat exchanger body (B) side in the first direction (D1).

[0106] Next, a method for connecting the heat transfer tubes 42 to the front plate assembly 50 will be described.

[0107] First, as shown in FIG. 10, the container (53a), the O-ring (71), and the heat transfer tube (42) are arranged so as to be aligned in the first direction (D1).

[0108] Next, as shown in Fig. 11, the O-ring (71) is placed in the receiving portion (53a). The O-ring (71) is deformed so as to fit closely to the inner circumferential surface of the receiving portion (53a). The inner diameter of the O-ring (71) is reduced compared to before the O-ring (71) was placed in the receiving portion (53a).

[0109] After the O-ring (71) is accommodated in the accommodation portion (53a), the heat transfer tube (42) is inserted into the insertion hole (72a) of the holding member (72).

[0110] Next, as shown in FIG. 12 , the heat transfer tube (42) is inserted into the front insertion portion (53). The heat transfer tube (42) is inserted until it abuts against the second front plate (522). The inner portion of the O-ring (71) is pushed open by the heat transfer tube (42). On the other hand, the outer portion of the O-ring (71) is prevented from expanding by the housing portion (53a). Therefore, the elastic force of the O-ring (71) pushes the heat transfer tube (42) radially inward.

[0111] After the heat transfer tube (42) is inserted into the front insertion portion (53), the holding member (72) is screwed to the first front plate (521). At this time, the O-ring (71) is crushed by the holding member (72). As the O-ring (71) is crushed, the heat transfer tube (42) is pressed by the O-ring (71) with a force greater than that before the holding member (72) was fixed to the first front plate (521).

[0112] In this manner, the heat transfer tubes 42 are connected to the front plate assembly 50. Because the heat transfer tubes 42 are pressed radially inward by the O-rings 71, a frictional force acts between the outer circumferential surfaces of the heat transfer tubes 42 and the O-rings 71. This frictional force suppresses movement of the heat transfer tubes 42 in the first direction D1. In this manner, the fixing portion 70, which does not have a melt-solidified portion, suppresses movement of the heat transfer tubes 42 in the first direction D1.

[0113] In the above example, the heat transfer tube (42) is inserted into the insertion hole (72a) of the holding member (72) after the O-ring (71) is accommodated in the accommodation portion (53a), but the heat transfer tube (42) may be inserted into the insertion hole (72a) of the holding member (72) before the O-ring (71) is accommodated in the accommodation portion (53a). In the above example, the heat transfer tube (42) is inserted into the front insertion portion (53) and then the holding member (72) is screwed to the first front plate (521). However, the heat transfer tube (42) may be inserted into the front insertion portion (53) after the holding member (72) is screwed to the first front plate (521). In the above-described example, the O-ring (71) is accommodated in the accommodation portion (53a) and then the heat transfer tube (42) is inserted into the front insertion portion (53). However, the O-ring (71) may be attached to the heat transfer tube (42) in advance, and the O-ring (71) may be accommodated in the accommodation portion (53a) together with the heat transfer tube (42).

[0114] (6) Driving behavior The air conditioner (10) performs cooling operation, heating operation, and dehumidifying operation.

[0115] (6-1) Cooling operation In the cooling operation, the controller of the air conditioner (10) operates the compressor (21), the outdoor fan (25), and the indoor fan (32), sets the four-way switching valve (24) to the first state (the state shown by the solid line in FIG. 1), appropriately adjusts the opening of the outdoor expansion valve (23), and fully opens the indoor expansion valve (37).

[0116] During the cooling operation, the refrigerant circuit (11) performs a refrigeration cycle in which the outdoor heat exchanger (22) functions as a condenser (heat radiator) and the indoor heat exchanger (40) functions as an evaporator.

[0117] The indoor unit (30) draws indoor air from the indoor space (I) into the air passage (P) through the inlet (33). The air in the air passage (P) is cooled by the indoor heat exchanger (40). The cooled air is supplied to the indoor space (I) through the outlet (34).

[0118] (6-2) Heating operation In the heating operation, the controller of the air conditioner (10) operates the compressor (21), the outdoor fan (25), and the indoor fan (32), sets the four-way switching valve (24) to the second state (the state indicated by the dashed line in FIG. 1 ), adjusts the opening of the outdoor expansion valve (23) to a predetermined opening, and fully opens the indoor expansion valve (37).

[0119] During the heating operation, the refrigerant circuit (11) performs a refrigeration cycle in which the indoor heat exchanger (40) functions as a condenser (heat radiator) and the outdoor heat exchanger (22) functions as an evaporator.

[0120] The indoor unit (30) draws indoor air from the indoor space (I) into the air passage (P) through the inlet (33). The air in the air passage (P) is heated by the indoor heat exchanger (40). The heated air is supplied to the indoor space (I) through the outlet (34).

[0121] (6-3) Dehumidification operation In the dehumidifying operation, the controller of the air conditioner (10) operates the compressor (21), the outdoor fan (25), and the indoor fan (32), sets the four-way switching valve (24) to the first state (the state shown by the solid line in Figure 1), and appropriately adjusts the openings of the outdoor expansion valve (23) and the indoor expansion valve (37).

[0122] During the dehumidifying operation, the refrigerant circuit (11) performs a refrigeration cycle in which the outdoor heat exchanger (22) and the front heat exchange section (40A) of the indoor heat exchanger (40) function as condensers (radiators), and the rear heat exchange section (40B) of the indoor heat exchanger (40) functions as an evaporator.

[0123] The indoor unit (30) draws room air from the indoor space (I) into the air passage (P) through the inlet (33). The rear heat exchanger (40B) cools the air in the air passage (P) to a temperature below the dew point. The front heat exchanger (40A) heats the air in the air passage (P). The air passing through both the rear heat exchanger and the front heat exchanger mixes in the air passage (P) to produce low-humidity air. The dehumidified air is supplied to the indoor space (I) through the outlet (34).

[0124] (7) Effects of the First Embodiment In the first embodiment, the fins 41 are surface-treated. If the front plate assembly 50 and the heat transfer tubes 42 are brazed together in a heat treatment furnace, the effect of the surface treatment on the fins 41 may be reduced. While it is conceivable to locally braze the front plate assembly 50 and the heat transfer tubes 42 together using a burner, the front plates 521 to 525 may be heated by thermal convection during brazing using the burner, which may re-melt the brazing material joining the front plates together.

[0125] In contrast, in the first embodiment, the heat transfer tubes (42) are fixed to the front plate stack (50) by the fixing portions (70) that are not melt-solidified portions that melt and solidify by heat, so as to suppress movement in the first direction (D1). Fixing the heat transfer tubes (42) to the front plate stack (50) without using a member that melts and solidifies by heat, such as brazing material, suppresses remelting of the brazing material between the front plates (521-525) when connecting the heat transfer tubes (42) to the front plate stack (50). Therefore, it is possible to fix the plurality of heat transfer tubes (42) to the front plate stack (50) while suppressing remelting of the brazing material between the front plates (521-525).

[0126] In the first embodiment, the fixing portion (70) includes an O-ring (71) that presses the heat transfer tube (42) from the radially outer side toward the radially inner side, and a holding member (72) that sandwiches the O-ring (71) in the stacking direction and is attached to the first front plate (521). Pressing the heat transfer tube (42) in the radial direction with the O-ring (71) suppresses movement of the heat transfer tube (42) in the first direction and also suppresses wobbling of the heat transfer tube (42) in the radial direction.

[0127] In the first embodiment, the O-ring (71) is an elastic member. The O-ring (71) can radially press the heat transfer tube (42) by its own elastic force. This allows the heat transfer tube (42) to be fixed to the front plate assembly (50) with a simple structure.

[0128] In the first embodiment, before the heat transfer tube (42) is inserted into the O-ring (71), the inner diameter of the O-ring (71) is smaller than the outer diameter of the heat transfer tube (42). When the heat transfer tube (42) is inserted into the O-ring (71), the elastic force of the O-ring (71) can press the heat transfer tube (42) in the radial direction. This allows the heat transfer tube (42) to be fixed to the front plate assembly (50) with a simple configuration.

[0129] In the first embodiment, the first front plate (521) has an annular housing portion (53a) for housing the O-ring (71), and the maximum width of the housing portion (53a) as viewed in the first direction (D1) is smaller than the outer diameter of the O-ring (71) before it is housed in the housing portion (53a). When the O-ring (71) is housed in the housing portion (53a), the O-ring (71) is compressed radially inward, thereby ensuring contact between the inner circumferential surface of the housing portion (53a) and the O-ring (71). Friction occurs between the heat transfer tube (42) and the O-ring (71), and friction also occurs between the inner circumferential surface of the housing portion (53a) and the O-ring (71), thereby restricting movement of the heat transfer tube (42) in the first direction (D1). Furthermore, since the gap between the inner circumferential surface of the receiving portion (53a) and the heat transfer tube (42) is filled with the O-ring (71), it is possible to prevent the heat transfer tube (42) from wobbling in the radial direction.

[0130] In the first embodiment, the thickness of the O-ring (71) is greater than the depth of the accommodation portion (53a) from the first left side surface (52a) before the holding member (72) is fixed to the first front plate (521). When the holding member (72) is fixed to the first front plate (521), the O-ring (71) is crushed by the holding member (72). The O-ring (71) contracts in diameter and presses against the heat transfer tube (42). The O-ring (71) fills the accommodation portion (53a) over the entire depth direction of the accommodation portion (53a). This prevents the O-ring (71) from moving in the first direction (D1) within the accommodation portion (53a). This prevents the heat transfer tube (42) from moving in the first direction (D1).

[0131] In the first embodiment, the holding member (72) is a plate-like member. Even when a plurality of heat transfer tubes (42) are provided, the heat transfer tubes (42) can be collectively fixed to the front plate assembly (50) by one holding member (72).

[0132] In the first embodiment, the holding member 72 is made of the same material as the front plates 521 to 525. Even if the holding member 72 comes into contact with the front plates 521 to 525, electrolytic corrosion is unlikely to occur between the holding member 72 and the front plates 521 to 525. Therefore, the heat transfer tube 42 can be maintained fixed to the front plate assembly 50 for a long period of time.

[0133] In the first embodiment, the thickness of the retaining member (72) in the first direction (D1) is smaller than the thickness of the front plates (521-525). Even if the retaining member (72) is provided, the indoor heat exchanger (40) is prevented from becoming longer in the first direction (D1). Therefore, the indoor heat exchanger (40) can be made compact while the heat transfer tubes (42) are fixed to the front plate stack (50).

[0134] In the first embodiment, the shortest distance (L) between the fin (41) closest to the front plate stack (50) and the retaining member (72) is 30 mm or less. Even if the retaining member (72) is provided, the indoor heat exchanger (40) is prevented from becoming longer in the first direction (D1). Therefore, the indoor heat exchanger (40) can be made compact while the heat transfer tubes (42) are fixed to the front plate stack (50).

[0135] In the first embodiment, the holding member (72) is fixed to the first front plate (521) with screws. The fixed state between the holding member (72) and the first front plate (521) can be easily maintained with a simple configuration, and therefore the fixed state of the heat transfer tube (42) can be maintained for a long period of time. Furthermore, even if a repulsive load is applied to the holding member (72) when the O-ring (71) is crushed by the holding member (72), the fastening force of the screws (73) can maintain the crushed state of the O-ring (71).

[0136] Second Embodiment The embodiments of the present disclosure will be described in detail with reference to the drawings. In the following description, parts common to the first embodiment will be denoted by the same reference numerals, and detailed description thereof will be omitted.

[0137] (8) Fixed part As shown in Fig. 13, in the second embodiment, the fixing portion (270) includes a ring member (271) and holding members (72) attached to the first front plate (521) and sandwiching the ring member (271) in the stacking direction. In the second embodiment, the fixing portion (270) is not a melt-solidified portion that melts and solidifies by heat. The fixing portion (270) between the heat transfer tube (42) and the front plate assembly (50) will be described in detail below. The fixing portion between the heat transfer tube (42) and the rear plate assembly (60) has the same configuration as the fixing portion (270) between the heat transfer tube (42) and the front plate assembly (50), and therefore a detailed description thereof will be omitted.

[0138] As shown in Fig. 14, two ring members (271) are provided side by side in the first direction (D1). The ring members (271) are housed in housing portions (53a) formed in the first front plate (521). The ring members (271) include leaf springs (271a), connecting portions (271b) that connect the leaf springs (271a), and supporting portions (271c) that support the leaf springs (271a). The number of ring members (271) may be one, or three or more.

[0139] The leaf spring (271a) is inclined radially inward of the heat transfer tube (42) and toward the front plate stack (50) in the first direction (D1). The leaf spring (271a) is biased radially inward and toward the heat exchanger body (B) in the first direction (D1). The biasing force of the leaf spring (271a) presses the heat transfer tube (42) radially inward and toward the heat exchanger body (B) in the first direction (D1).

[0140] 15, a plurality of leaf springs (271a) are provided. The leaf springs (271a) are arranged side by side in the circumferential direction of the heat transfer tube (42). The number of leaf springs (271a) is not limited to a specific number.

[0141] The connecting portion (271b) connects the plurality of leaf springs (271a) to one another, is integral with radially outer ends of the leaf springs (271a), and has an annular shape that extends along the circumferential direction of the heat transfer tube (42).

[0142] The support portion (271c) is a metal ring extending in the circumferential direction of the heat transfer tube (42). A radially inner portion of the support portion (271c) is an inclined surface (271d) that inclines radially inward toward the front plate stack (50) in the first direction (D1). A gap is formed between the inclined surface (271d) and the leaf spring (271a).

[0143] A seal member (280) is disposed between the first front plate (521) and the ring member (271). The seal member (280) is, for example, an O-ring made of an elastic material such as rubber.

[0144] In the second embodiment, the heat transfer tube (42) is connected to the front plate assembly (50) with the seal member (280) and the ring member (271) housed in the housing portion (53a). A gap is formed between the inclined surface (271d) of the support portion (271c) and the leaf spring (271a). Therefore, the leaf spring (271a) can rotate radially outward and in the first direction (D1) toward the front plate assembly (50) around the connecting portion (271b). When the heat transfer tube (42) is inserted into the front insertion portion (53), the leaf spring (271a) rotates radially outward and in the first direction (D1) toward the front plate assembly (50) against the biasing force. This allows the heat transfer tube (42) to be inserted into the front insertion portion (53). As shown in FIG. 13, the heat transfer tube (42) is inserted until it abuts against the second front plate (522).

[0145] After the heat transfer tube (42) is inserted into the front insertion portion (53), when an attempt is made to pull the heat transfer tube (42) in the first direction (D1) to remove it from the front insertion portion (53), friction occurs between the leaf spring (271a) and the heat transfer tube (42). The friction causes the leaf spring (271a) to rotate radially inward in the first direction (D1) toward the heat exchanger body (B) around the connecting portion (271b) as a fulcrum, but the rotation is prevented by the heat transfer tube (42). As a result, the leaf spring (271a) becomes caught on the heat transfer tube (42), and movement of the heat transfer tube (42) in the first direction (D1) is suppressed.

[0146] (9) Effects of the Second Embodiment In the second embodiment, the heat transfer tubes (42) are fixed to the front plate stack (50) by the fixing portions (270) that are not melt-solidified portions that melt and solidify by heat, so as to suppress movement in the first direction (D1). Fixing the heat transfer tubes (42) to the front plate stack (50) without using a member that melts and solidifies by heat, such as brazing material, suppresses remelting of the brazing material between the front plates (521-525) when connecting the heat transfer tubes (42) to the front plate stack (50). Therefore, it is possible to fix the plurality of heat transfer tubes (42) to the front plate stack (50) while suppressing remelting of the brazing material between the front plates (521-525).

[0147] In the second embodiment, the fixing portion (270) includes a ring member (271) having a leaf spring (271a) biased radially inward and toward the heat exchanger body (B) in the first direction (D1), and a holding member (72) attached to the first front plate (521) and sandwiching the ring member (271) in the stacking direction. When an attempt is made to move the heat transfer tube (42) toward the heat exchanger body (B), the leaf spring (271a) catches on the heat transfer tube (42), thereby preventing the heat transfer tube (42) from moving toward the heat exchanger body (B). Therefore, the heat transfer tube (42) can be fixed to the front plate stack (50) with a simple configuration.

[0148] In the second embodiment, a gap is formed between the leaf spring (271a) and a radially inner portion of the support portion (271c) that supports the leaf spring (271a). The gap allows the leaf spring (271a) to rotate radially outward and in the first direction (D1) toward the front plate stack (50) around the connecting portion (271b). This allows the heat transfer tube (42) to be smoothly inserted into the front insertion portion (53). However, as described above, after the heat transfer tube (42) is inserted into the front insertion portion (53), the leaf spring (271a) prevents the heat transfer tube (42) from moving in the first direction (D1) toward the front heat exchange portion (40A).

[0149] In the second embodiment, a seal member (280) is disposed between the first front plate (521) and the ring member (271). The seal member (280) can suppress movement of the heat transfer tube (42) in the first direction (D1) and ensure sealing of the refrigerant channel (51).

[0150] Third Embodiment A third embodiment of the present disclosure will be described in detail with reference to the drawings. In the following description, parts common to the first to third embodiments will be given the same reference numerals, and detailed description thereof will be omitted.

[0151] (10) Fixed part As shown in Fig. 16, in the third embodiment, the fixing portion (370) includes a protruding portion (371) protruding radially outward from a side surface of the heat transfer tube (42), and a holding member (72) attached to the first front plate (521) across the protruding portion (371) in the stacking direction. In the third embodiment, the fixing portion (370) is not a melt-solidified portion that melts and solidifies by heat. The fixing portion (370) between the heat transfer tube (42) and the front plate stack (50) will be described in detail below. The fixing portion between the heat transfer tube (42) and the rear plate stack (60) has the same configuration as the fixing portion (370) between the heat transfer tube (42) and the front plate stack (50), and therefore a detailed description thereof will be omitted.

[0152] 17, the protrusion (371) is an expanded diameter portion (42a) formed by expanding the diameter of a part of the heat transfer tube (42) radially outward. The expanded diameter portion (42a) is formed by beading the heat transfer tube (42). The protrusion (371) is accommodated in an accommodation portion (53a) formed in the first front plate (521).

[0153] The protrusion (371) has flat surfaces (371a) extending in the radial direction. The flat surfaces (371a) are provided on the front plate stack (50) side and the front heat exchange section (40A) side in the first direction (D1). One of the flat surfaces (371a) is in surface contact with the first front plate (521). The other flat surface (371a) is in surface contact with the holding member (72).

[0154] 18, the protrusion (371) is provided over the entire circumferential direction of the heat transfer tube (42). The protrusion (371) has a circular shape when viewed from the first direction (D1).

[0155] A seal member (380) is disposed between the radially outer end of the protrusion (371) and the side surface of the storage portion (53a). The seal member (380) is, for example, an O-ring made of an elastic material such as rubber. The inner diameter of the seal member (380) is slightly smaller than the outer diameter of the protrusion (371).

[0156] In the third embodiment, the heat transfer tubes (42) are connected to the front plate assembly (50) with the sealing members (380) accommodated in the accommodation portions (53a) and the holding members (72) disposed in advance between the protrusions (371) and the fins (41). When the holding members (72) are fixed to the first front plate (521), even if the heat transfer tubes (42) are moved in the first direction (D1), the protrusions (371) are caught by the holding members (72) and the first front plate (521). This prevents the heat transfer tubes (42) from moving in the first direction (D1).

[0157] (11) Effects of the Third Embodiment In the third embodiment, the heat transfer tubes (42) are fixed to the front plate stack (50) by fixing portions (370) that are not melt-solidified portions that melt and solidify by heat, so as to suppress movement in the first direction (D1). Fixing the heat transfer tubes (42) to the front plate stack (50) without using a member that melts and solidifies by heat, such as brazing material, suppresses remelting of the brazing material between the front plates (521-525) when connecting the heat transfer tubes (42) to the front plate stack (50). Therefore, it is possible to fix the plurality of heat transfer tubes (42) to the front plate stack (50) while suppressing remelting of the brazing material between the front plates (521-525).

[0158] In the third embodiment, the fixing portion (370) includes a protrusion (371) that protrudes radially outward from a side surface of the heat transfer tube (42), and a holding member (72) that is attached to the first front plate (521) and sandwiches the protrusion (371) in the stacking direction. When an attempt is made to move the heat transfer tube (42) in the first direction, the protrusion (371) is caught by the holding member (72) and the first front plate (521), thereby suppressing movement of the heat transfer tube (42). The heat transfer tube (42) can be fixed to the front plate stack (50) with a simple configuration.

[0159] In the third embodiment, the protrusion (371) is an expanded diameter portion (42a) formed by expanding the diameter of a part of the heat transfer tube (42) radially outward. The heat transfer tube (42) can be fixed to the front plate assembly (50) without using any other member.

[0160] In the third embodiment, the protrusion (371) has a flat surface (371a) that comes into contact with the first front plate (521). Since the protrusion (371) and the first front plate (521) are in surface contact with each other, movement of the heat transfer tube (42) in the first direction (D1) can be effectively suppressed. Furthermore, since relatively large friction acts between the flat surface (371a) and the first front plate (521), movement of the heat transfer tube (42) in the radial direction can be suppressed.

[0161] In the third embodiment, a seal member (380) is arranged between the protrusion (371) and the first front plate (521), which can suppress movement of the heat transfer tube (42) in the first direction and ensure sealing of the refrigerant channel (51).

[0162] In the third embodiment, the seal member (380) is disposed between the radially outer end of the protrusion (371) and the side surface of the housing portion (53a), thereby preventing the heat transfer tube (42) from moving radially.

[0163] Fourth Embodiment A fourth embodiment of the present disclosure will be described in detail with reference to the drawings. In the following description, parts common to the first to fourth embodiments will be given the same reference numerals, and detailed description thereof will be omitted.

[0164] (12) Fixed part 19, in the fourth embodiment, the fixing portion 470 is made of adhesive. In the fourth embodiment, too, the fixing portion 470 is not a melt-solidified portion that melts and solidifies due to heat.

[0165] The first front plate (521) has a burring portion (53b) formed by burring the periphery of the front insertion portion (53). The burring portion (53b) protrudes from the first left side surface (52a) toward the front heat exchange portion (40A).

[0166] The fixing portion 470 is formed from the front insertion portion 53 to the burring portion 53b.

[0167] The fixing portion between the heat transfer tube (42) and the rear plate stack (60) has the same configuration as the fixing portion (470) between the heat transfer tube (42) and the front plate stack (50), and therefore a detailed description thereof will be omitted.

[0168] (14) Effects of the fourth embodiment In the fourth embodiment, the heat transfer tubes (42) are fixed to the front plate stack (50) by fixing portions (470) that are not melt-solidified portions that melt and solidify by heat, so as to suppress movement in the first direction (D1). Fixing the heat transfer tubes (42) to the front plate stack (50) without using a member that melts and solidifies by heat, such as brazing material, suppresses remelting of the brazing material between the front plates (521-525) when connecting the heat transfer tubes (42) to the front plate stack (50). Therefore, it is possible to fix the plurality of heat transfer tubes (42) to the front plate stack (50) while suppressing remelting of the brazing material between the front plates (521-525).

[0169] In the fourth embodiment, the fixing portion (470) is an adhesive. The heat transfer tube (42) can be easily fixed to the first front plate (521). Furthermore, the contact area between the heat transfer tube (42) and the front plates (521-525) can be reduced, thereby minimizing electrolytic corrosion between the heat transfer tube (42) and the front plates (521-525). This makes it easier to maintain the fixed structure between the heat transfer tube (42) and the front plate assembly (50).

[0170] In the fourth embodiment, the first front plate (521) has a burring portion (53b). The burring portion (53b) can make the fixing portion (470) as wide as possible, thereby effectively suppressing the movement of the heat transfer tube (42) in the first direction.

[0171] (15) Variations Although the container portion (53a) has an annular shape when viewed in the first direction (D1), it may have a rectangular shape when viewed in the first direction (D1).

[0172] Although the receiving portion (53a) is provided in the first front plate (521), it may be provided in the holding member (72).

[0173] The holding member (72) may be fixed to the first front plate (521) with an adhesive instead of being screwed to the first front plate (521).

[0174] In embodiment 1, the inner diameter of the O-ring (71) only needs to be smaller than the outer diameter of the heat transfer tube (42) when the O-ring (71) is accommodated in the accommodation portion (53a), and does not need to be smaller than the outer diameter of the heat transfer tube (42) before the O-ring (71) is accommodated in the accommodation portion (53a).

[0175] In the third embodiment, the protrusion 371 does not necessarily have to have a flat surface 371a that comes into contact with the holding member 72. Furthermore, the protrusion 371 does not necessarily have to have any flat surface 371a.

[0176] In the third embodiment, the sealing member (380) may be disposed between the bottom surface of the storage section (53a) and the protruding portion (371). In this case, the protruding portion (371) may extend to a position where it abuts against the side surface of the storage section (53a).

[0177] In the third embodiment, the protrusion (371) is circular when viewed from the first direction (D1), but it may be C-shaped when viewed from the first direction (D1). In this case, it is preferable to provide a sealing member (380) between the bottom surface of the storage section (53a) and the protrusion (371) or between the holding member (72) and the protrusion (371).

[0178] In the third embodiment, the protrusion (371) may be formed by welding another member to the outer periphery of the heat transfer tube (42) instead of the expanded diameter portion (42a) of the heat transfer tube (42).

[0179] (16) Other embodiments The above-described structure for connecting the heat transfer tube (42) and the plate stack (50) may be employed for the outdoor heat exchanger (22).

[0180] The heat exchanger body (B) does not have to be of the fin-and-tube type, and may be, for example, of a corrugated type in which corrugated fins are arranged between adjacent heat transfer tubes.

[0181] The heat exchanger body (B) may have a single heat exchange section, without including the front heat exchange section (40A) and the rear heat exchange section (40B). In this case, the first internal pipe (38), the second internal pipe (39), and the indoor expansion valve (37) are omitted.

[0182] The heat transfer tube (42) may be a flat tube. The cross-sectional shape of the flat tube, taken perpendicular to the axial direction, is an ellipse, an oval, or a substantially rectangular shape extending along the air flow direction. Strictly speaking, the flat tube is a flat multi-hole tube having a plurality of flow paths through which the refrigerant flows. When the heat transfer tube (42) is a flat tube, the shapes of the accommodation portion (53a), the O-ring (71), the ring member (271), and the protrusion (371) are changed depending on the shape of the heat transfer tube (42).

[0183] A header collecting pipe connected to the heat transfer tubes (42) may be provided at the other end of the heat exchanger (40) in the first direction. In this case, the header collecting pipe is provided instead of the U-shaped pipes (48) of the above-described embodiment. The header collecting pipe has a refrigerant flow path formed therein that communicates with the heat transfer tubes (42). The header collecting pipe is formed in a tubular shape with both axial ends closed. The header collecting pipe is formed in a cylindrical or rectangular tubular shape.

[0184] Although the embodiments and modifications have been described above, it will be understood that various modifications in form and details are possible without departing from the spirit and scope of the claims. Furthermore, the above embodiments, modifications, and other embodiments may be combined or substituted as appropriate as long as the functionality of the subject matter of the present disclosure is not impaired.

[0185] The terms "first," "second," "third," etc. mentioned above are used to distinguish the terms to which these terms are attached, and do not limit the number or order of the terms. [Industrial Applicability]

[0186] As described above, the present disclosure is useful for heat exchangers. [Explanation of symbols]

[0187] 40 Indoor heat exchanger 40A Front heat exchanger 41 Finn 42 Heat transfer tube 42a Expanded diameter part 50 Front plate stack 51 refrigerant flow path 53a Storage section 70 Fixed part 71 O-ring 72 Retaining member 270 Fixed part 271 Ring member 271a Leaf spring 280 Sealing material 370 Fixed part 371 Protrusion 371a Plane part 380 Sealing material 470 Fixed part D1 1st direction L Shortest distance

Claims

1. a heat exchange section (40A) having fins (41) and a plurality of heat transfer tubes (42); a plate stack (50) configured by stacking a plurality of plates (521-525) in a stacking direction and brazing them to one another, the plate stack (50) having a refrigerant flow path (51) therein that communicates with the heat transfer tube (42), and the plate stack (50) is connected to the heat transfer tube (42); the heat transfer tube (42) is connected to the plate stack (50) via a fixing portion (70, 270, 370, 470) that fixes the heat transfer tube (42) to the plate stack (50) so as to suppress movement of the heat transfer tube (42) in a first direction that is an axial direction of the heat transfer tube (42); The fixed portion (70, 270, 370, 470) is a heat exchanger that is not a melt-solidification portion.

2. 2. The heat exchanger according to claim 1, The fixing portion (70, 270) a radial pressing member (71, 271) that presses the heat transfer tube (42) from the radially outer side toward the radially inner side; a holding member (72) attached to the plate (521) and sandwiching the radial pressing member (71, 271) in the stacking direction; A heat exchanger having:

3. 3. The heat exchanger according to claim 2, The radial pressing member (71) is an annular elastic member disposed around the heat transfer tube (42).

4. 4. The heat exchanger according to claim 3, At least one of the plate (521) and the holding member (72) has an annular receiving portion (53a) in which the elastic member is received, A heat exchanger in which the maximum width of the accommodation portion (53a), as viewed from the first direction, is smaller than the outer diameter of the elastic member before being accommodated in the accommodation portion (53a).

5. 3. The heat exchanger according to claim 2, The radial pressing member (271) is a ring member (271) having a leaf spring (271a) biased radially inward and toward the heat exchange portion (40A) in the first direction.

6. 6. The heat exchanger according to claim 5, A heat exchanger, wherein a seal member (280) is disposed between the plate (521) and the ring member (271).

7. 2. The heat exchanger according to claim 1, The fixing portion (370) a protrusion (371) protruding radially outward from a side surface of the heat transfer tube (42); a holding member (72) attached to the plate (521) so as to sandwich the protrusion (371) in the stacking direction; A heat exchanger having:

8. 8. The heat exchanger according to claim 7, The heat exchanger, wherein the protrusion (371) is an expanded diameter portion (42a) formed by expanding the diameter of a part of the heat transfer tube (42) radially outward.

9. 8. The heat exchanger according to claim 7, The protrusion (371) has a flat surface (371a) that comes into contact with the plate (521).

10. 8. The heat exchanger according to claim 7, A heat exchanger, wherein a seal member (380) is disposed between the protrusion (371) and the plate (521).

11. The heat exchanger according to any one of claims 2 to 10, The holding member (72) is a plate-shaped member of the heat exchanger.

12. 12. The heat exchanger according to claim 11, A heat exchanger in which the holding member (72) is made of the same material as the plate (521).

13. 12. The heat exchanger according to claim 11, A heat exchanger in which the thickness of the holding member (72) in the first direction is smaller than the thickness of the plate (521).

14. 13. The heat exchanger of claim 12, The holding member (72) is fixed to the plate (521) by screws.

15. 12. The heat exchanger according to claim 11, The holding member (72) is adhered to the plate (521) with an adhesive.

16. The heat exchanger according to any one of claims 2 to 10, The heat exchanger, wherein the shortest distance (L) between the fin (41) and the holding member (72) is 30 mm or less.

17. 2. The heat exchanger according to claim 1, The fixing portion (470) is an adhesive.

18. The heat exchanger according to any one of claims 1 to 10 and 17, The end of the heat transfer tube (42) on the plate stack (50) side in the first direction penetrates the first plate (521) of the plurality of plates (521-525) that is located closest to the heat exchange section (40A), and abuts against the plate (522) that is located farther from the heat exchange section (40A) than the first plate (521).

19. 20. The heat exchanger of claim 18, A heat exchanger in which the inside of the heat transfer pipe (42) partially overlaps with the refrigerant flow path (51) when viewed from the heat exchange section (40A) side in the first direction.

Images