Heat exchanger unit, air conditioning indoor unit, refrigeration cycle device, and method for manufacturing heat exchanger unit

Abstract

A heat exchanger unit (150) comprises a first heat exchanging unit (50), a second heat exchanging unit (55), and a plate structure (100). The first heat exchanging unit (50) has a plurality of first fins (52) and a plurality of first heat transfer pipes (51). The second heat exchange unit (55) has a plurality of second fins (57) and a plurality of second heat transfer pipes (56). The plate structure (100) is joined to the first heat transfer pipes (51) and the second heat transfer pipes (56). First flow passages (121) for connecting the first heat transfer pipes (51) together and second flow passages (122) for connecting the second heat transfer pipes (56) together are formed inside the plate structure (100).

Description

Heat exchanger unit, air conditioning indoor unit, refrigeration cycle device, and method for manufacturing heat exchanger unit

[0001] The present disclosure relates to a heat exchanger unit, an air conditioning indoor unit, a refrigeration cycle device, and a method for manufacturing a heat exchanger unit.

[0002] Patent Document 1 discloses a heat exchanger including a heat exchanger body composed of fins and heat transfer tubes, and a plate stack. A refrigerant flow path is formed inside the plate stack, connecting the heat transfer tubes of the heat exchanger body. The plate stack is formed by stacking a plurality of plate members.

[0003] Japanese Patent Application Laid-Open No. 2006-125652

[0004] The heat exchanger body of the heat exchanger may have a plurality of heat exchange sections, each having fins and heat transfer tubes, and in this case, it is conceivable to join one heat exchange section to one plate stack.

[0005] When joining the heat exchange unit and the plate stack, all of the heat transfer tubes of the heat exchange unit need to be assembled to the plate stack at once. Therefore, if the heat exchange unit has a relatively large number of heat transfer tubes, it can be difficult to align each heat transfer tube of the heat exchange unit with the plate stack, which can increase the time required to assemble the heat exchange unit and the plate stack.

[0006] An object of the present disclosure is to reduce the time required for assembling a heat exchange section and a plate stack.

[0007] A first aspect of the present disclosure is a heat exchanger unit (150) that exchanges heat between air and a refrigerant, the heat exchanger unit (150) including a first heat exchange section (50) having a plurality of first fins (52) and a plurality of first heat transfer tubes (51), a second heat exchange section (55) having a plurality of second fins (57) and a plurality of second heat transfer tubes (56), and a plate structure (100) joined to the first heat transfer tubes (51) and the second heat transfer tubes (56), and having formed therein a first flow path (121) that connects the first heat transfer tubes (51) to each other, and a second flow path (122) that connects the second heat transfer tubes (56) to each other.

[0008] In the first embodiment, both the first heat exchange section (50) and the second heat exchange section (55) are joined to the plate structure (100). In the process of combining the first heat exchange section (50) and the second heat exchange section (55) with the plate structure (100), the relative position of the plate structure (100) with respect to the first heat transfer tube (51) of the first heat exchange section (50) and the relative position of the plate structure (100) with respect to the second heat transfer tube (56) of the second heat exchange section (55) can be adjusted individually. Therefore, compared to the case where "one large heat exchanger section that exhibits a heat exchange capacity equivalent to the sum of the heat exchange capacities of the first heat exchanger section (50) and the second heat exchanger section (55)" is combined with the plate structure (100), it is easier to adjust the relative positions of the first heat transfer tube (51) of the first heat exchanger section (50) and the second heat transfer tube (56) of the second heat exchanger section (55) with the plate structure (100). Therefore, according to this embodiment, the time required for the work of combining the first heat exchanger section (50) and the second heat exchanger section (55) with the plate structure (100) can be shortened, and the time required for manufacturing the heat exchanger unit (150) can be shortened.

[0009] A second aspect of the present disclosure is the first aspect, wherein a connecting flow path (131) connecting the first heat transfer pipe (51) and the second heat transfer pipe (56) is formed inside the plate structure (100).

[0010] In the second embodiment, a first flow path (121), a second flow path (122), and a connecting flow path (131) are formed inside the plate structure (100).

[0011] A third aspect of the present disclosure is such that, in the first or second aspect, each of the plurality of first fins (52) is formed in a plate shape having a pair of linear long sides (52a, 52b) that are parallel to each other, and each of the plurality of first heat transfer tubes (51) penetrates the plurality of first fins (52) that are arranged in a row, while each of the plurality of second fins (57) is formed in a plate shape having a pair of linear long sides (57a, 57b) that are parallel to each other, and each of the plurality of second heat transfer tubes (56) penetrates the plurality of second fins (57) that are arranged in a row.

[0012] In the first heat exchange section (50) of the third embodiment, a plurality of plate-like first fins (52) are arranged in a row, and the first heat transfer tube (51) penetrates through the plurality of first fins (52) arranged in a row. In the second heat exchange section (55) of this embodiment, a plurality of plate-like second fins (57) are arranged in a row, and the second heat transfer tube (56) penetrates through the plurality of second fins (57) arranged in a row.

[0013] A fourth aspect of the present disclosure is any one of the first to third aspects, further comprising a third heat exchange section (60) having a plurality of third fins (62) and a plurality of third heat transfer tubes (61), the plate structure (100) is connected to the third heat transfer tubes (61), and a third flow path (123) connecting the third heat transfer tubes (61) to each other is formed inside the plate structure (100).

[0014] In the fourth aspect, the heat exchanger unit (150) includes a first heat exchange section (50), a second heat exchange section (55), and a third heat exchange section (60). A third flow path (123) formed in the plate structure (100) connects the third heat transfer tubes (61) of the third heat exchange section (60) to each other.

[0015] A fifth aspect of the present disclosure is any one of the first to fourth aspects, wherein the plate structure (100) comprises a plate-shaped main body (106) having the first flow path (121) and the second flow path (122) formed therein, and a plurality of connecting pipe parts (135) protruding from the main body part (106), each having a base end connected to the first flow path (121) or the second flow path (122), and each having a tip connected to the first heat transfer pipe (51) or the second heat transfer pipe (56), and the diameter of the tip of each of the plurality of connecting pipe parts (135) is smaller than the diameter of the base end.

[0016] In a fifth aspect, the diameter of each connecting pipe portion (135) at its tip end connected to the first heat transfer pipe (51) or the second heat transfer pipe (56) is smaller than the diameter of its base end connected to the main body portion (106) of the plate structure (100). The refrigerant flowing from the first heat transfer pipe (51) or the second heat transfer pipe (56) into the connecting pipe portion (135) flows from the relatively small-diameter tip end to the relatively large-diameter base end and then flows into the first flow path (121) or the second flow path (122) of the main body portion (106). This reduces the pressure loss of the refrigerant flowing out of the first heat transfer pipe (51) or the second heat transfer pipe (56) and into the first flow path (121) or the second flow path (122).

[0017] A sixth aspect of the present disclosure is any one of the first to fifth aspects, wherein in the first heat exchange section (50), a plurality of the first fins (52) arranged in a line form a first fin group (53), and in the second heat exchange section (55), a plurality of the second fins (57) arranged in a line form a second fin group (58), and the plate structure (100) is arranged on one end side of the first fin group (53) in the arrangement direction of the first fins (52). and one end side of the second fin group (58) in the arrangement direction of the second fins (57), and the heat exchanger unit (150) includes a holding member (155) that is provided at the other end side of the first fin group (53) in the arrangement direction of the first fins (52) and the other end side of the second fin group (58) in the arrangement direction of the second fins (57), and that holds the first heat exchange section (50) and the second heat exchange section (55).

[0018] In a heat exchanger unit (150) of the sixth aspect, a plate structure (100) is arranged on one end side of the first fin group (53) and the second fin group (58). At one end side of the first fin group (53) and the second fin group (58), the relative positions of the first heat exchange section (50) and the second heat exchange section (55) are maintained by the plate structure (100) joined to the first heat transfer tube (51) and the second heat transfer tube (56). In addition, in the heat exchanger unit (150), a holding member (155) is arranged on the other end side of the first fin group (53) and the second fin group (58). At the other end side of the first fin group (53) and the second fin group (58), the relative positions of the first heat exchange section (50) and the second heat exchange section (55) are maintained by the holding member (155).

[0019] A seventh aspect of the present disclosure is directed to an air conditioning indoor unit (30), and comprises the heat exchanger unit (150) of the third aspect and a casing (31) that houses the heat exchanger unit (150), and the first heat exchange section (50) is arranged above the second heat exchange section (55) in an orientation in which the angle formed between the long sides (52a, 52b) of the first fin (52) and the long sides (57a, 57b) of the second fin (57) is less than 180°.

[0020] In the air conditioner indoor unit (30) of the seventh aspect, a heat exchanger unit (150) is housed in a casing (31). Within the casing (31), the first heat exchange section (50) is located above the second heat exchange section (55). The angle formed between the long sides (52a, 52b) of the first fin (52) and the long sides (57a, 57b) of the second fin (57) is less than 180°.

[0021] An eighth aspect of the present disclosure is the seventh aspect, wherein the first heat exchange section (50) is arranged in an orientation where the long side (52a) on the air inlet side of the first fin (52) faces upward, and the second heat exchange section (55) is arranged in an orientation where the long side (57a) on the air inlet side of the second fin (57) faces downward.

[0022] In the eighth aspect, the long side (52a) on the air inlet side of each first fin (52) of the first heat exchange section (50) faces upward, and the long side (57a) on the air inlet side of each second fin (57) of the second heat exchange section (55) faces downward.

[0023] A ninth aspect of the present disclosure is the eighth aspect, wherein the lower end of the first fin (52) of the first heat exchange section (50) is aligned with the long side (57b) on the air outlet side of the second fin (57) of the second heat exchange section (55).

[0024] In the ninth aspect, the condensed water generated in the first heat exchange section (50) flows down from the lower ends of the first fins (52) to the second heat exchange section (55) and flows along the second fins (57) of the second heat exchange section (55). Therefore, scattering of the condensed water from the first heat exchange section (50) is suppressed.

[0025] A tenth aspect of the present disclosure is the ninth aspect, wherein a connection flow path (131a) connecting the first heat transfer pipe (51) and the second heat transfer pipe (56) is formed inside the plate structure (100), the first heat transfer pipe (51) communicating with the connection flow path (131a) is one of the plurality of first heat transfer pipes (51) arranged in a row along the long side (52a) on the air inflow side of the first fin (52), and the second heat transfer pipe (56) communicating with the connection flow path (131a) is one of the plurality of second heat transfer pipes (56) arranged in a row along the long side (57b) on the air outflow side of the second fin (57).

[0026] In the tenth aspect, a connecting flow path (131a) formed in the plate structure (100) connects the first heat transfer tube (51) closest to the long side (52a) on the air inlet side of the first fin (52) and the second heat transfer tube (56) closest to the long side (57b) on the air outlet side of the second fin (57).

[0027] An eleventh aspect of the present disclosure is the ninth or tenth aspect, wherein the distance between the respective central axes of the two first heat transfer tubes (51) that are closest to each other is a first distance, the distance between the respective central axes of the two second heat transfer tubes (56) that are closest to each other is a second distance, the distance between the respective central axes of the first heat transfer tube (51) and the second heat transfer tube (56) that are closest to each other is a third distance, and the third distance is less than or equal to the first distance and less than or equal to the second distance.

[0028] In the eleventh aspect, the first heat exchange section (50) and the second heat exchange section (55) are provided at positions where the third distance is not more than the first distance and is not more than the second distance.

[0029] A twelfth aspect of the present disclosure is any one of the eighth to eleventh aspects, wherein the number of the first heat transfer tubes (51) in the first heat exchange section (50) is greater than the number of the second heat transfer tubes (56) in the second heat exchange section (55).

[0030] In the twelfth aspect, the number of first heat transfer pipes (51) in the first heat exchange section (50) is greater than the number of second heat transfer pipes (56) in the second heat exchange section (55). Therefore, the heat exchange capacity of the first heat exchange section (50) is greater than the heat exchange capacity of the second heat exchange section (55).

[0031] A thirteenth aspect of the present disclosure is any one of the eighth to twelfth aspects, wherein the angle formed between the long sides (52a, 52b) of the first fin (52) of the first heat exchange section (50) and the vertical direction is 30° or more.

[0032] In the thirteenth aspect, the first heat exchange section (50) is provided in the casing (31) in an orientation such that the angle between the long sides (52a, 52b) of the upwardly disposed first fins (52) and the vertical direction is 30° or more. This allows the first heat exchange section (50) to be increased in size without increasing the height of the casing (31). As a result, the heat exchange capacity of the entire heat exchanger unit (150) can be improved without increasing the size of the casing (31).

[0033] A fourteenth aspect of the present disclosure is any one of the eighth to thirteenth aspects, wherein the angle formed between the long sides (52a, 52b) of the first fin (52) of the first heat exchange section (50) and the vertical direction is 60° or less.

[0034] In the fourteenth aspect, the first heat exchange section (50) is provided in the casing (31) in an orientation such that the angle formed between the long sides (52a, 52b) of the upwardly facing first fins (52) and the vertical direction is 60° or less. Therefore, condensed water generated on the surfaces of the first fins (52) flows down along the surfaces of the first fins (52) to the lower ends of the first fins (52). As a result, scattering of the condensed water generated on the surfaces of the first fins (52) is suppressed.

[0035] A fifteenth aspect of the present disclosure is any one of the eighth to fourteenth aspects, wherein the spacing between the plurality of first fins (52) in the first heat exchange section (50) is equal to the spacing between the plurality of second fins (57) in the second heat exchange section (55).

[0036] In the fifteenth aspect, the spacing between the second fins (57) of the second heat exchange section (55) matches the spacing between the first fins (52) of the first heat exchange section (50). Therefore, the second fin (57) is disposed below each of the first fins (52) of the first heat exchange section (50). Condensed water generated on the surfaces of the first fins (52) flows down from the lower end of the first fin (52) to the corresponding second fin (57) and further flows down along the second fin (57). Therefore, scattering of the condensed water generated on the surfaces of the first fins (52) is suppressed.

[0037] A sixteenth aspect of the present disclosure is any one of the eighth to fifteenth aspects, wherein the distance from the first fin (52) located at one end in the arrangement direction of the plurality of first fins (52) to the first fin (52) located at the other end is the effective length of the first heat exchange section (50), the distance from the second fin (57) located at one end in the arrangement direction of the plurality of second fins (57) to the second fin (57) located at the other end is the effective length of the second heat exchange section (55), and the effective length of the first heat exchange section (50) is less than or equal to the effective length of the second heat exchange section (55).

[0038] In the sixteenth aspect, the effective length of the first heat exchange section (50) located above the second heat exchange section (55) is equal to or less than the effective length of the second heat exchange section (55). Therefore, all of the condensed water flowing down from the first heat exchange section (50) is received by the second heat exchange section (55).

[0039] A seventeenth aspect of the present disclosure is any one of the seventh to sixteenth aspects, wherein the heat exchanger unit (150) is arranged in an orientation in which the air inlet surfaces (54, 59) of the first heat exchange section (50) and the second heat exchange section (55) face the front or rear side of the casing (31).

[0040] In the seventeenth aspect, inside the casing of the air conditioning indoor unit, the air inlet faces (54, 59) of the first heat exchange section (50) and the second heat exchange section (55) face the front or rear of the casing (31).

[0041] An eighteenth aspect of the present disclosure is directed to a refrigeration cycle apparatus (10), which includes a refrigerant circuit (11) connected to any one of the first to sixth heat exchanger units (150).

[0042] In the eighteenth aspect, a heat exchanger unit (150) is provided in a refrigerant circuit (11) of a refrigeration cycle apparatus (10).

[0043] A nineteenth aspect of the present disclosure is a method for manufacturing a heat exchanger unit (150) that exchanges heat between air and a refrigerant, the heat exchanger unit (150) including a plurality of heat exchange sections, each having fins and heat transfer tubes, and a plate structure (100) joined to the heat transfer tubes of the plurality of heat exchange sections. The plurality of heat exchange sections include first heat exchange sections (50) each having a plurality of first fins (52) and first heat transfer tubes (51), and second heat exchange sections (55) each having a plurality of second fins (57) and second heat transfer tubes (56). Refrigerant flow paths formed inside the plate structure (100) include first flow paths (121) connecting the first heat transfer tubes (51) to each other and second flow paths (122) connecting the second heat transfer tubes (56) to each other. The manufacturing method of this aspect includes a holding step of holding the plurality of heat exchange sections so that the relative positions of the plurality of heat exchange sections are the same as the relative positions of the plurality of heat exchange sections in the heat exchanger unit (150) which is the finished product; an assembling step of combining the plate structure (100) with the plurality of heat exchange sections held in predetermined positions in the holding step; and a joining step of joining the heat transfer tubes of the plurality of heat exchange sections combined in the assembling step to the plate structure (100) by brazing.

[0044] In the nineteenth aspect, a holding step, an assembling step, and a joining step are performed. In the holding step, a plurality of heat exchange sections, including a first heat exchange section (50) and a second heat exchange section (55), are held so that their relative positions are the same as the "relative positions of the plurality of heat exchange sections in the heat exchanger unit (150) that is the finished product." In the assembling step, a plate structure (100) is combined with the plurality of heat exchange sections held in predetermined positions in the holding step. In the assembling step, the relative positions of each heat exchange section and the plate structure (100) can be individually fine-tuned. In the joining step, the heat transfer tubes of the plurality of heat exchange sections combined in the assembling step are joined to the plate structure (100) by brazing.

[0045] A twentieth aspect of the present disclosure is a method for manufacturing a heat exchanger unit (150) that exchanges heat between air and a refrigerant, the heat exchanger unit (150) including a plurality of heat exchange sections, each having fins and heat transfer tubes, and a plate structure (100) joined to the heat transfer tubes of the plurality of heat exchange sections. The plurality of heat exchange sections include first heat exchange sections (50) each having a plurality of first fins (52) and first heat transfer tubes (51), and second heat exchange sections (55) each having a plurality of second fins (57) and second heat transfer tubes (56). Refrigerant flow paths formed inside the plate structure (100) include first flow paths (121) connecting the first heat transfer tubes (51) to each other and second flow paths (122) connecting the second heat transfer tubes (56) to each other. The manufacturing method of this aspect includes an assembling step of assembling a plurality of the heat exchange units one by one in order to the plate structure (100), and a joining step of joining the heat transfer tubes of the plurality of heat exchange units assembled in the assembling step to the plate structure (100) by brazing.

[0046] In the twentieth aspect, an assembling step and a joining step are performed. In the assembling step, a plurality of heat exchange units are assembled one by one in order to the plate structure (100). Therefore, in the assembling step, the operation of assembling the first heat exchange unit (50) to the plate structure (100) and the operation of assembling the second heat exchange unit (55) to the plate structure (100) are performed separately. In the joining step, the heat transfer tubes of the plurality of heat exchange units assembled in the assembling step are joined to the plate structure (100) by brazing.

[0047] FIG. 1 is a piping diagram of an air conditioning apparatus according to an embodiment. FIG. 2 is a front view of an air conditioning indoor unit. FIG. 3 is a cross-sectional view of the air conditioning indoor unit. FIG. 4 is a front view of a heat exchanger unit. FIG. 5 is an enlarged view of a portion of FIG. 4. FIG. 6 is a cross-sectional view of the heat exchanger unit taken along the line VI-VI in FIG. 5. FIG. 7 is a right side view of the heat exchanger unit. FIG. 8 is a cross-sectional view of the heat exchanger unit taken along the line VIII-VIII in FIG. 5. FIG. 9 is a cross-sectional view of the heat exchanger unit taken along the line IX-IX in FIG. 5. FIG. 10 is a cross-sectional view of the heat exchanger unit taken along the line XX in FIG. 5. FIG. 11 is a cross-sectional view of a main portion of a first heat exchange section and a front plate laminate showing the joining state of a first heat transfer tube and a connecting pipe portion. FIG. 12 is a cross-sectional view of a heat exchanger unit according to a first modified example, corresponding to FIG. 6. FIG. 13 is a cross-sectional view of a heat exchanger unit according to a second modified example, corresponding to FIG. 6. FIG. 14 is a cross-sectional view of a heat exchanger unit according to a third modified example, corresponding to FIG. 6. FIG. 15 is an enlarged view showing a part of the first heat exchange section of FIG.

[0048] 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.

[0049] (1) Overall Configuration of Air Conditioner This embodiment is an air conditioner (10) including a heat exchanger unit (150). The air conditioner (10) adjusts the temperature of air in an indoor space (I) which is a target space.

[0050] As shown in Fig. 1, the air conditioner (10) is an example of a refrigeration cycle apparatus 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.

[0051] 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. In the air conditioner (10), a refrigerant circuit (11) is formed by connecting the outdoor unit (20) and the indoor unit (30) with the first connecting pipe (12) and the second connecting pipe (13).

[0052] 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 switching valve (24), and an outdoor fan (25) housed in the outdoor casing (20a).

[0053] The compressor (21) is a rotary compressor such as a swing piston type, rotary type, or scroll type. The outdoor heat exchanger (22) is a fin-and-tube air heat exchanger. The outdoor heat exchanger (22) exchanges heat between the refrigerant and outdoor air. The outdoor expansion valve (23) is an electronic expansion valve with a variable opening. The four-way selector valve (24) switches between a first state (shown by the solid line in FIG. 1 ) and a second state (shown by the 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) is a propeller fan.

[0054] The indoor unit (30) includes a casing (31), and a heat exchanger unit (150) and an indoor fan (32) housed in the casing (31).

[0055] (2) Indoor Unit The indoor unit (30), which is an indoor air conditioner, will be described in detail with reference to Figures 2 to 4. The indoor unit (30) of this embodiment is a wall-mounted type that is installed on a wall of the indoor space (I). Note that the terms "upper," "lower," "right," "left," "front," and "rear" described below correspond to the directions of the arrows shown in Figures 2 and 3 and indicate directions when the indoor unit (30) is viewed from the front.

[0056] (2-1) Casing 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).

[0057] 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).

[0058] 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 (left-right 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).

[0059] (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 indoor heat exchanger (40). The filter (35) collects dust in the air sent from the air inlet (33) to the indoor heat exchanger (40). The indoor unit (30) may include a dust removal mechanism that removes the dust collected by the filter (35).

[0060] (2-3) Heat Exchanger Unit The heat exchanger unit (150) includes one indoor heat exchanger (40) and one indoor expansion valve (160). The indoor heat exchanger (40) includes one heat exchanger body (45) and two plate stacks (100, 110). The heat exchanger body (45) 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 (45).

[0061] (2-4) Indoor Fan The indoor fan (32) is arranged in the air passage (P). The indoor fan (32) is arranged 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).

[0062] (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 a plurality of flaps (36). The flap (36) may adjust the air direction in the horizontal direction.

[0063] (3) Heat Exchanger Unit As described above, the heat exchanger unit (150) includes the indoor heat exchanger (40), the indoor expansion valve (160), the gas relay pipe (163), the liquid relay pipe (164), and the retaining member (155).

[0064] (3-1) Indoor Heat Exchanger As described above, the indoor heat exchanger (40) includes one heat exchanger body (45) and two plate stacks (100, 110). The indoor heat exchanger (40) is a fin-and-tube air heat exchanger. The indoor heat exchanger (40) exchanges heat between the refrigerant and the indoor air. Each plate stack (100, 110) is a plate structure. The number of plate stacks (100, 110) included in the indoor heat exchanger (40) is merely an example.

[0065] (3-2) Heat Exchanger Body As shown in Figures 3 and 6, the heat exchanger body (45) has a front heat exchange section (40A) and a rear heat exchange section (40B). The front heat exchange section (40A) is located closer to the front plate (31a) of the casing (31). The rear heat exchange section (40B) is located closer to the rear plate (31b) of the casing (31). The heat exchanger body (45) is disposed so as to surround the front, upper, and rear sides of the indoor fan (32).

[0066] (3-3) Front Plate Stack and Rear Plate Stack In the indoor heat exchanger (40), the front plate stack (100) and the rear plate stack (110) are disposed on the right side of the heat exchanger body (45) in Fig. 4. The front plate stack (100) is attached to the front heat exchange section (40A), and the rear plate stack (110) is attached to the rear heat exchange section (40B).

[0067] (3-4) Indoor Expansion Valve, Gas Relay Pipe, and Liquid Relay Pipe The indoor expansion valve (160) is an electronic expansion valve with a variable opening. The indoor expansion valve (160) is connected to the front plate stack (100) via a first internal pipe (161) and to the rear plate stack (110) via a second internal pipe (162).

[0068] One end of the gas relay pipe (163) is connected to the rear plate stack (110). The other end of the gas relay pipe (163) is connected to the first interconnecting pipe (12) via a joint. One end of the liquid relay pipe (164) is connected to the front plate stack (100). The other end of the liquid relay pipe (164) is connected to the second interconnecting pipe (13) via a joint.

[0069] (3-5) Holding Member The holding member (155) is disposed on the left side of the indoor heat exchanger (40) in FIG. 4 . The holding member (155) is disposed on the opposite side of the indoor heat exchanger (40) from the front plate stack (100) and the rear plate stack (110). The holding member (155) is a resin member shaped to cover the left end of the indoor heat exchanger (40). The holding member (155) is attached to the front heat exchange section (40A) and the rear heat exchange section (40B) constituting the indoor heat exchanger (40), and holds the relative positions of the front heat exchange section (40A) and the rear heat exchange section (40B).

[0070] (4) Front Heat Exchange Section of Heat Exchanger Body As shown in FIG. 6, the front heat exchange section (40A) includes a first heat exchange section (50), a second heat exchange section (55), a third heat exchange section (60), and a fourth heat exchange section (65).

[0071] (4-1) First Heat Exchange Section The first heat exchange section (50) includes a plurality of first fins (52) and a plurality of first heat transfer tubes (51). The first fins (52) and the first heat transfer tubes (51) are made of an aluminum alloy. The first heat transfer tubes (51) may be made of a copper alloy. The number of first heat transfer tubes (51) provided in the first heat exchange section (50) is greater than the number of second heat transfer tubes (56) provided in the second heat exchange section (55) described later.

[0072] Each first fin (52) is a thin plate-like member having a pair of long sides (52a, 52b) that are substantially parallel to each other and a pair of short sides (52c, 52d) that are substantially parallel to each other. The first fins (52) are arranged in a line in the left-right direction in FIG. 4 and face each other. The first fins (52) arranged in a line constitute a first fin group (53). In the first fin group (53), the interval between adjacent first fins (52) (fin pitch FP1) is constant (see FIG. 5).

[0073] As shown in Figure 6, of the pair of long sides of each first fin (52), one long side located on the opposite side from the indoor fan (32) is the long side (52a) on the air inlet side, and the other long side located on the indoor fan (32) side is the long side (52b) on the air outlet side.

[0074] The first heat exchange section (50) is disposed in such a position that the long sides (52a) of the first fins (52) on the air inlet side face upward and the long sides (52b) of the first fins (52) on the air outlet side face downward. The angle θ formed by each of the long sides (52a, 52b) of the first fins (52) and the vertical direction is in the range of 30° to 60° (30°≦θ≦60°).

[0075] In the first fin group (53), the long side (52a) on the air inlet side of each first fin (52) forms a virtual first air inlet surface (54). The first air inlet surface (54) faces the front side of the indoor unit (30) and also faces diagonally upward from the indoor unit (30). The distance from the first fin (52) located at one end of the first fin group (53) to the first fin (52) located at the other end in the arrangement direction of the first fins (52) is the effective length EL1 of the first heat exchange section (50) (see FIG. 4 ).

[0076] Each first heat transfer tube (51) is a straight circular tube. The multiple first heat transfer tubes (51) are arranged substantially parallel to one another. Each first heat transfer tube (51) penetrates all of the first fins (52) constituting the first fin group (53) and extends in the left-right direction in FIG. 4. The right end of each first heat transfer tube (51) in FIG. 4 is an open end. Two adjacent first heat transfer tubes (51) are connected at their left ends in FIG. 4 by a U-shaped tube. The two first heat transfer tubes (51) and the U-shaped tube connecting them are seamlessly formed integrally.

[0077] The first heat exchange section (50) is formed with three tube rows (51a to 51c). Each tube row (51a to 51c) is composed of a plurality of first heat transfer tubes (51) arranged in a row in the extension direction of the long sides (52a, 52b) of the first fins (52). In each tube row (51a to 51c), the plurality of first heat transfer tubes (51) are arranged at regular intervals from one another. In the first heat exchange section (50), the tube row extending along the long side (52a) of the first fins (52) on the air inlet side is the first tube row (51a), the tube row extending along the long side (52b) of the first fins (52) on the air outlet side is the third tube row (51c), and the tube row located between the first tube row (51a) and the third tube row (51c) is the second tube row (51b).

[0078] (4-2) Second Heat Exchange Section The second heat exchange section (55) includes a plurality of second fins (57) and a plurality of second heat transfer tubes (56). The second fins (57) and the second heat transfer tubes (56) are made of an aluminum alloy. The second heat transfer tubes (56) may be made of a copper alloy.

[0079] Each second fin (57) is a thin plate-like member having a pair of long sides (57a, 57b) that are substantially parallel to each other and a pair of short sides (57c, 57d) that are substantially parallel to each other. The second fins (57) are aligned in a line in the left-right direction in FIG. 4 , facing each other. The second fins (57) aligned in a line constitute a second fin group (58). In the second fin group (58), the interval (FP2) between adjacent second fins (57) is constant (see FIG. 5 ). In this embodiment, the interval (FP2) between adjacent second fins (57) is equal to the interval (FP1) between adjacent first fins (52) (FP2=FP1).

[0080] As shown in Figure 6, of the pair of long sides of each second fin (57), one long side located on the side opposite the indoor fan (32) is the long side (57a) on the air inlet side, and the other long side located on the side closer to the indoor fan (32) is the long side (57b) on the air outlet side.

[0081] The second heat exchange section (55) is disposed such that the long sides (57a) of the second fins (57) on the air inlet side face downward and the long sides (57b) of the second fins (57) on the air outlet side face upward. The second heat exchange section (55) is disposed below the first heat exchange section (50). The angle ψ formed between the long sides (57b) of the second fins (57) on the air outlet side and the long sides (52b) of the first fins (52) on the air outlet side is less than 180°. The angle ψ in the front heat exchange section (40A) of this embodiment is approximately 90° to 110°.

[0082] The long side (57b) on the air outlet side of the second fin (57) has a portion including its upper end in contact with the lower short side (52d) of the first fin (52) constituting the first heat exchange section (50). The lower short side (52d) of the first fin (52) is the lower end of the first fin (52). Therefore, the lower end of the first fin (52) is along the long side (57b) on the air outlet side of the second fin (57).

[0083] In the second fin group (58), the long side (57a) on the air inlet side of each second fin (57) forms a virtual second air inlet surface (59). The second air inlet surface (59) faces the front side of the indoor unit (30) and also faces diagonally downward from the indoor unit (30).

[0084] The distance from the second fin (57) located at one end of the second fin group (58) in the arrangement direction of the second fins (57) to the second fin (57) located at the other end thereof is the effective length EL2 of the second heat exchange section (55) (see FIG. 4 ). The effective length EL2 of the second heat exchange section (55) is equal to the effective length EL1 of the first heat exchange section (50). The effective length EL2 of the second heat exchange section (55) may be longer than the effective length EL1 of the first heat exchange section (50).

[0085] Each second heat transfer tube (56) is a straight circular tube. The second heat transfer tubes (56) are arranged substantially parallel to one another. Each second heat transfer tube (56) penetrates all of the second fins (57) constituting the second fin group (58) and extends in the left-right direction in FIG. 4. The right end of each second heat transfer tube (56) in FIG. 4 is an open end. Two adjacent second heat transfer tubes (56) are connected at their left ends in FIG. 4 by a U-shaped tube. The two second heat transfer tubes (56) and the U-shaped tube connecting them are formed seamlessly and integrally.

[0086] The second heat exchange section (55) is formed with three tube rows (56a to 56c). Each tube row (56a to 56c) is composed of a plurality of second heat transfer tubes (56) arranged in a row in the extension direction of the long sides (57a, 57b) of the second fins (57). In each tube row (56a to 56c), the plurality of second heat transfer tubes (56) are arranged at regular intervals from one another. In the second heat exchange section (55), the tube row extending along the long side (57a) of the second fins (57) on the air inlet side is the first tube row (56a), the tube row extending along the long side (57b) of the second fins (57) on the air outlet side is the third tube row (56c), and the tube row located between the first tube row (56a) and the third tube row (56c) is the second tube row (56b).

[0087] In the front heat exchange section (40A) of the heat exchanger unit (150) of this embodiment, the shapes and relative positions of the first heat exchange section (50) and the second heat exchange section (55) are set so that the third distance D3 is shorter than the first distance D1 and is shorter than the second distance D2. However, in the front heat exchange section (40A), the shapes and relative positions of the first heat exchange section (50) and the second heat exchange section (55) may be set so that the third distance D3 is equal to the first distance D1 and is equal to the second distance D2.

[0088] The first distance D1 is the distance between the central axes of the two closest first heat transfer tubes (51). The second distance D2 is the distance between the central axes of the two closest second heat transfer tubes (56). The third distance D3 is the distance between the central axes of the closest first heat transfer tube (51) and second heat transfer tube (56).

[0089] (4-3) Third Heat Exchange Section The third heat exchange section (60) includes a plurality of third fins (62) and a plurality of third heat transfer tubes (61). The third fins (62) and the third heat transfer tubes (61) are made of an aluminum alloy. The third heat transfer tube (61) may be made of a copper alloy.

[0090] Each third fin (62) is a thin, pentagonal member formed by cutting off one corner of a rectangle. Each third fin (62) has a pair of long sides (62a, 62b) that are substantially parallel to each other. The third fins (62) are arranged in a line in the left-right direction in FIG. 4 and face each other. The third fins (62) arranged in a line constitute a third fin group (63). In the third fin group (63), the interval between adjacent third fins (62) is constant.

[0091] 6, the third heat exchange section (60) is disposed along the first air inlet surface (54) of the first heat exchange section (50). One long side (62b) of the third fin (62) constituting the third heat exchange section (60) is in contact with the long side (52a) on the air inlet side of the first fin (52) constituting the first heat exchange section (50).

[0092] Each third heat transfer tube (61) is a straight circular tube. The multiple third heat transfer tubes (61) are arranged substantially parallel to one another. Each third heat transfer tube (61) penetrates all of the third fins (62) constituting the third fin group (63) and extends in the left-right direction in FIG. 4. The right end of each third heat transfer tube (61) in FIG. 4 is an open end. Two adjacent third heat transfer tubes (61) are connected at their left ends in FIG. 4 by a U-shaped tube. The two third heat transfer tubes (61) and the U-shaped tube connecting them are formed seamlessly and integrally.

[0093] In the third heat exchange section (60), all the third heat transfer tubes (61) are arranged in a row along the long sides (62a, 62b) of the third fins (62). The third heat transfer tubes (61) are arranged at regular intervals from one another.

[0094] (4-4) Fourth Heat Exchange Section The fourth heat exchange section (65) includes a plurality of fourth fins (67) and a plurality of fourth heat transfer tubes (66). The fourth fins (67) and the fourth heat transfer tubes (66) are made of an aluminum alloy. The fourth heat transfer tubes (66) may be made of a copper alloy.

[0095] Each fourth fin (67) is a rectangular, thin plate-like member. Each fourth fin (67) has a pair of long sides (67a, 67b) that are substantially parallel to each other. The multiple fourth fins (67) are arranged in a line in the left-right direction in FIG. 4 and face each other. The multiple fourth fins (67) arranged in a line constitute a fourth fin group (68). In the fourth fin group (68), the interval between adjacent fourth fins (67) is constant.

[0096] 6, the fourth heat exchange section (65) is disposed along the second air inlet surface (59) of the second heat exchange section (55). One long side (67b) of the fourth fin (67) constituting the fourth heat exchange section (65) is in contact with the long side (57a) on the air inlet side of the second fin (57) constituting the second heat exchange section (55).

[0097] Each fourth heat transfer tube (66) is a straight circular tube. The plurality of fourth heat transfer tubes (66) are arranged substantially parallel to one another. Each fourth heat transfer tube (66) penetrates all of the fourth fins (67) constituting the fourth fin group (68) and extends in the left-right direction in FIG. 4 . The right end of each fourth heat transfer tube (66) in FIG. 4 is an open end. Two adjacent fourth heat transfer tubes (66) are connected at their left ends in FIG. 4 by a U-shaped tube. The two fourth heat transfer tubes (66) and the U-shaped tube connecting them are seamlessly formed integrally.

[0098] In the fourth heat exchange section (65), all of the fourth heat transfer tubes (66) are arranged in a row along the long sides (67a, 67b) of the fourth fins (67). The plurality of fourth heat transfer tubes (66) are arranged at regular intervals from one another.

[0099] (5) Rear Heat Exchange Section of Heat Exchanger Body As shown in FIG. 6, the rear heat exchange section (40B) includes a fifth heat exchange section (70) and a sixth heat exchange section (75).

[0100] (5-1) Fifth Heat Exchange Section The fifth heat exchange section (70) includes a plurality of fifth fins (72) and a plurality of fifth heat transfer tubes (71). The fifth fins (72) and the fifth heat transfer tubes (71) are made of an aluminum alloy. The fifth heat transfer tubes (71) may be made of a copper alloy.

[0101] Each fifth fin (72) is a thin plate-like member having a pair of long sides (72a, 72b) that are substantially parallel to each other and a pair of short sides (72c, 72d) that are substantially parallel to each other. The plurality of fifth fins (72) are arranged in a line in the left-right direction in FIG. 4 and facing each other. The plurality of fifth fins (72) arranged in a line constitute a fifth fin group (73). In the fifth fin group (73), the interval between adjacent fifth fins (72) is constant.

[0102] As shown in Figure 6, of the pair of long sides of each fifth fin (72), one long side located on the side opposite the indoor fan (32) is the long side (72a) on the air inlet side, and the other long side located on the indoor fan (32) side is the long side (72b) on the air outlet side.

[0103] The fifth heat exchange section (70) is disposed in an orientation in which the long sides (72a) of the fifth fins (72) on the air inlet side face upward and the long sides (72b) of the fifth fins (72) on the air outlet side face downward. The angles formed by the long sides (72a, 72b) of the fifth fins (72) and the vertical direction are equal to or greater than 30° and equal to or less than 60°.

[0104] In the fifth fin group (73), the long side (52a) on the air inlet side of each fifth fin (72) forms a virtual fifth air inlet surface (74). The fifth air inlet surface (74) faces the rear side of the indoor unit (30) and also faces diagonally upward from the indoor unit (30).

[0105] Each fifth heat transfer tube (71) is a straight circular tube. The plurality of fifth heat transfer tubes (71) are arranged substantially parallel to one another. Each fifth heat transfer tube (71) penetrates all of the fifth fins (72) constituting the fifth fin group (73) and extends in the left-right direction in FIG. 4. The right end of each fifth heat transfer tube (71) in FIG. 4 is an open end. Two adjacent fifth heat transfer tubes (71) are connected at their left ends in FIG. 4 by a U-shaped tube. The two fifth heat transfer tubes (71) and the U-shaped tube connecting them are seamlessly formed integrally.

[0106] The fifth heat exchange section (70) is formed with two tube rows (71a, 71b). Each tube row (71a, 71b) is composed of a plurality of fifth heat transfer tubes (71) arranged in a row in the extension direction of the long sides (72a, 72b) of the fifth fin group (73). In each tube row (71a, 71b), the plurality of fifth heat transfer tubes (71) are arranged at regular intervals from one another. In the fifth heat exchange section (70), the tube row extending along the long sides (72a) of the fifth fins (72) on the air inlet side is the first tube row (71a), and the tube row extending along the long sides (72b) of the fifth fins (72) on the air outlet side is the second tube row (71b).

[0107] (5-2) Sixth Heat Exchange Section The sixth heat exchange section (75) includes a plurality of sixth fins (77) and a plurality of sixth heat transfer tubes (76). The sixth fins (77) and the sixth heat transfer tubes (76) are made of an aluminum alloy. The sixth heat transfer tubes (76) may be made of a copper alloy.

[0108] Each sixth fin (77) is a rectangular, thin plate-like member. Each sixth fin (77) has a pair of long sides (77a, 77b) that are substantially parallel to each other. The sixth fins (77) are arranged in a line in the left-right direction in FIG. 4 and face each other. The sixth fins (77) arranged in a line constitute a sixth fin group (78). In the sixth fin group (78), the interval between adjacent sixth fins (77) (=fin pitch FP6) is constant.

[0109] 6, the sixth heat exchange section (75) is disposed along the fifth air inlet surface (74) of the fifth heat exchange section (70). One long side (77b) of the sixth fin (77) constituting the sixth heat exchange section (75) is in contact with the air inlet-side long side (72a) of the fifth fin (72) constituting the fifth heat exchange section (70).

[0110] Each sixth heat transfer tube (76) is a straight circular tube. The sixth heat transfer tubes (76) are arranged substantially parallel to one another. Each sixth heat transfer tube (76) penetrates all of the sixth fins (77) constituting the sixth fin group (78) and extends in the left-right direction in FIG. 4. The right end of each sixth heat transfer tube (76) in FIG. 4 is an open end. Two adjacent sixth heat transfer tubes (76) are connected at their left ends in FIG. 4 by a U-shaped tube. The two sixth heat transfer tubes (76) and the U-shaped tube connecting them are formed seamlessly and integrally.

[0111] In the sixth heat exchange section (75), all the sixth heat transfer tubes (76) are arranged in a row along the long sides (77a, 77b) of the sixth fins (77). The sixth heat transfer tubes (76) are arranged at regular intervals from one another.

[0112] (6) Front Plate Stack As shown in Figures 7 to 10, the front plate stack (100) is attached to the front heat exchange section (40A). The front plate stack (100) is arranged to cover the end (the right end in Figure 4) of the front heat exchange section (40A).

[0113] 5, the front plate stack (100) includes five front plates (101-105) and a plurality of connecting pipe portions (135). The five front plates (101-105) form a main body portion (106) of the front plate stack (100). Note that the number of front plates (101-105) forming the front plate stack (100) is merely an example.

[0114] The main body (106) of the front plate stack (100) is a thick plate-like member formed by stacking five front plates (101-105). The front plate stack (100) includes a first front plate (101), a second front plate (102), a third front plate (103), a fourth front plate (104), and a fifth front plate (105) stacked together in order from the front heat exchange section (40A). The five front plates (101-105) are joined to one another by furnace brazing.

[0115] The five front plates (101-105) are flat members with a common outer edge shape. Each of the front plates (101-105) is made of an aluminum alloy. The material of each of the front plates (101-105) is not limited to an aluminum alloy and may be, for example, a copper alloy or stainless steel. The first front plate (101) and the fifth front plate (105) have a thickness of, for example, 1.5 mm. The second front plate (102), the third front plate (103), and the fourth front plate (104) have a thickness of, for example, 3.0 mm.

[0116] (6-1) First Front Plate, Connecting Pipe Portion As shown in Fig. 5, the first front plate (101) is connected to the first heat exchange section (50), the second heat exchange section (55), the third heat exchange section (60), and the fourth heat exchange section (65). The first front plate (101) is connected to each of the first heat transfer tubes (51) of the first heat exchange section (50), each of the second heat transfer tubes (56) of the second heat exchange section (55), each of the third heat transfer tubes (61) of the third heat exchange section (60), and each of the fourth heat transfer tubes (66) of the fourth heat exchange section (65) via connecting pipe portions (135). One connecting pipe portion (135) is provided corresponding to each of the first heat transfer tubes (51), all of the second heat transfer tubes (56), all of the third heat transfer tubes (61), and all of the fourth heat transfer tubes (66).

[0117] The connecting pipe portion (135) is a short, cylindrical member. The connecting pipe portion (135) is made of an aluminum alloy. The material of the connecting pipe portion (135) is not limited to an aluminum alloy and may be, for example, a copper alloy or stainless steel. One end of each connecting pipe portion (135) is inserted into an open end of the corresponding heat transfer tube (51, 56, 61, 66) and joined to the corresponding heat transfer tube (51, 56, 61, 66) by brazing. The other end of each connecting pipe portion (135) is inserted into a through-hole formed in the first front plate (101) and joined to the first front plate (101) by brazing. The connecting pipe portion (135) may be formed seamlessly and integrally with the first front plate (101).

[0118] (6-2) Second Front Plate As shown in Fig. 8, the second front plate (102) is formed with a plurality of first flow paths (121), a plurality of second flow paths (122), and a plurality of first connecting flow paths (131). Each of the first flow paths (121), each of the second flow paths (122), and each of the first connecting flow paths (131) is an elongated hole that penetrates the second front plate (102) in the thickness direction.

[0119] The first flow path (121) connects the first heat transfer tubes (51) of the first heat exchange section (50) to each other. The first flow path (121) communicates with the corresponding two first heat transfer tubes (51) via the connecting pipe portion (135). The first flow path (121) is a flow path through which the refrigerant flows between the corresponding two first heat transfer tubes (51).

[0120] The second flow path (122) connects the second heat transfer tubes (56) of the second heat exchange section (55) to each other. The second flow path (122) communicates with the corresponding two second heat transfer tubes (56) via the connecting pipe portion (135). The second flow path (122) is a flow path through which the refrigerant flows between the corresponding two second heat transfer tubes (56).

[0121] The first connection flow path (131) connects the first heat transfer pipe (51) of the first heat exchange section (50) and the second heat transfer pipe (56) of the second heat exchange section (55). The first connection flow path (131) communicates with the corresponding first heat transfer pipe (51) and second heat transfer pipe (56) via a connection pipe portion (135). The first connection flow path (131) is a flow path through which the refrigerant flows between the corresponding first heat transfer pipe (51) and second heat transfer pipe (56).

[0122] The second front plate (102) is formed with circular through holes corresponding to the first heat transfer tube (51) of the first heat exchange section (50), the second heat transfer tube (56) of the second heat exchange section (55), the third heat transfer tube (61) of the third heat exchange section (60), and the fourth heat transfer tube (66) of the fourth heat exchange section (65).

[0123] 9 , the third front plate (103) has formed therein flow paths that communicate with the first heat transfer tube (51) of the first heat exchange section (50) or the second heat transfer tube (56) of the second heat exchange section (55). Furthermore, the third front plate (103) has formed therein circular through-holes that correspond to the first heat transfer tube (51) of the first heat exchange section (50), the second heat transfer tube (56) of the second heat exchange section (55), the third heat transfer tube (61) of the third heat exchange section (60), and the fourth heat transfer tube (66) of the fourth heat exchange section (65), respectively.

[0124] (6-4) Fourth Front Plate As shown in Fig. 10, the fourth front plate (104) is formed with a plurality of first flow paths (121), a plurality of second flow paths (122), and a plurality of first connecting flow paths (131). Each of the first flow paths (121), each of the second flow paths (122), and each of the first connecting flow paths (131) is an elongated hole that penetrates the fourth front plate (104) in the thickness direction.

[0125] The first flow paths (121), like the first flow paths (121) of the second front plate (102), communicate with two corresponding first heat transfer tubes (51) and allow the refrigerant to flow between the two corresponding first heat transfer tubes (51). The second flow paths (122), like the second flow paths (122) of the second front plate (102), communicate with two corresponding second heat transfer tubes (56) and allow the refrigerant to flow between the two corresponding second heat transfer tubes (56). The first connecting flow paths (131), like the first connecting flow paths (131) of the second front plate (102), communicate with the corresponding first heat transfer tubes (51) and second heat transfer tubes (56) and allow the refrigerant to flow between the corresponding first heat transfer tubes (51) and second heat transfer tubes (56).

[0126] In the fourth front plate (104), one first connection flow path (131a) of the plurality of first connection flow paths (131) connects one of the first heat transfer tubes (51) constituting the first tube row (51a) of the first heat exchange section (50) to one of the second heat transfer tubes (56) constituting the third tube row (56c) of the second heat exchange section (55). Thus, this first connection flow path (131a) connects one of the first heat transfer tubes (51) arranged in a row along the long side (52a) on the air inlet side of the first fin (52) to one of the second heat transfer tubes (56) arranged in a row along the long side (57b) on the air outlet side of the second fin (57).

[0127] The fourth front plate (104) is formed with two third flow paths (123), one fourth flow path (124), and one second connecting flow path (132).

[0128] The third flow path (123) connects the third heat transfer tubes (61) of the third heat exchange section (60) to each other. The third flow path (123) communicates with the corresponding two third heat transfer tubes (61) via the connecting pipe portion (135). The third flow path (123) is a flow path through which the refrigerant flows between the corresponding two third heat transfer tubes (61).

[0129] The fourth flow path (124) connects the fourth heat transfer tubes (66) of the fourth heat exchange section (65) to each other. The fourth flow path (124) communicates with the corresponding two fourth heat transfer tubes (66) via the connecting pipe portion (135). The fourth flow path (124) is a flow path through which the refrigerant flows between the corresponding two fourth heat transfer tubes (66).

[0130] The second connection flow path (132) connects the third heat transfer pipe (61) of the third heat exchange section (60) and the fourth heat transfer pipe (66) of the fourth heat exchange section (65). The second connection flow path (132) communicates with the corresponding third heat transfer pipe (61) and fourth heat transfer pipe (66) via the connection pipe portion (135). The second connection flow path (132) is a flow path through which the refrigerant flows between the corresponding third heat transfer pipe (61) and fourth heat transfer pipe (66).

[0131] (6-5) Fifth Front Plate The fifth front plate (105) covers the flow passages formed inside the front plate stack (100). As shown in FIG. 7 , one end of the first internal pipe (161) and one end of the liquid relay pipe (164) are connected to the fifth front plate (105). The first internal pipe (161) and the liquid relay pipe (164) are joined to the fifth front plate (105) by brazing. The first internal pipe (161) and the liquid relay pipe (164) are in communication with the flow passages formed inside the front plate stack (100).

[0132] (7) Rear Plate Stack As shown in Figures 7 to 10, the rear plate stack (110) is attached to the rear heat exchange section (40B). The rear plate stack (110) is arranged to cover the end (the right end in Figure 4) of the rear heat exchange section (40B).

[0133] 5, the rear plate stack (110) includes five rear plates (111-115) and a plurality of connecting pipe portions (135). The five rear plates (111-115) form a main body portion (116) of the rear plate stack (110). Note that the number of rear plates (111-115) forming the rear plate stack (110) is merely an example.

[0134] The main body (116) of the rear plate stack (110) is a thick plate-like member formed by stacking five rear plates (111-115). The rear plate stack (110) includes a first rear plate (111), a second rear plate (112), a third rear plate (113), a fourth rear plate (114), and a fifth rear plate (115) stacked together in order from the rear heat exchange section (40B). The five rear plates (111-115) are joined to one another by furnace brazing.

[0135] The five rear plates (111-115) are flat members having a common outer edge shape. The rear plates (111-115) are made of an aluminum alloy. The material of the rear plates (111-115) is not limited to an aluminum alloy and may be, for example, a copper alloy or stainless steel. The first rear plate (111) and the fifth rear plate (115) have a thickness of, for example, 1.5 mm. The second rear plate (112), the third rear plate (113), and the fourth rear plate (114) have a thickness of, for example, 3.0 mm.

[0136] (7-1) First Rear Plate, Connecting Pipe Portion The first rear plate (111) is connected to the fifth heat exchange section (70) and the sixth heat exchange section (75). The first rear plate (111) is connected to each of the fifth heat transfer tubes (71) of the fifth heat exchange section (70) and each of the sixth heat transfer tubes (76) of the sixth heat exchange section (75) via connecting pipe portions (135). One connecting pipe portion (135) is provided corresponding to each of the fifth heat transfer tubes (71) and each of the sixth heat transfer tubes (76).

[0137] The connecting pipe portion (135) is a short, cylindrical member made of aluminum alloy, similar to the connecting pipe portion (135) provided in the front plate stack (100). One end of each connecting pipe portion (135) is inserted into an open end of the corresponding heat transfer tube (71, 76) and joined to the corresponding heat transfer tube (71, 76) by brazing. The other end of each connecting pipe portion (135) is inserted into a through-hole formed in the first rear plate (111) and joined to the first rear plate (111) by brazing. The connecting pipe portion (135) may be formed seamlessly and integrally with the first rear plate (111).

[0138] (7-2) Second Rear Plate As shown in Fig. 8, the second rear plate (112) is formed with one fifth flow path (125) and two third connecting flow paths (133). The fifth flow path (125) and each of the third connecting flow paths (133) are elongated holes that penetrate the second rear plate (112) in the thickness direction.

[0139] The fifth flow path (125) connects the fifth heat transfer tubes (71) of the fifth heat exchange section (70) to each other. The fifth flow path (125) communicates with the corresponding two fifth heat transfer tubes (71) via the connecting pipe portion (135). The fifth flow path (125) is a flow path through which the refrigerant flows between the corresponding two fifth heat transfer tubes (71).

[0140] The third connection flow path (133) connects the fifth heat transfer tube (71) of the fifth heat exchange section (70) and the sixth heat transfer tube (76) of the sixth heat exchange section (75). The third connection flow path (133) communicates with the corresponding fifth heat transfer tube (71) and sixth heat transfer tube (76) via the connection pipe portion (135). The third connection flow path (133) is a flow path through which the refrigerant flows between the corresponding fifth heat transfer tube (71) and sixth heat transfer tube (76).

[0141] The second rear plate (112) is formed with circular through holes corresponding to the fifth heat transfer tube (71) of the fifth heat exchange section (70) and the sixth heat transfer tube (76) of the sixth heat exchange section (75).

[0142] (7-3) Third Rear Plate As shown in Fig. 9, the third rear plate (113) is formed with one fifth flow path (125). Like the fifth flow path (125) of the second rear plate (112), the fifth flow path (125) is a flow path that communicates with the corresponding two fifth heat transfer tubes (71) and allows the refrigerant to flow between the corresponding two fifth heat transfer tubes (71).

[0143] The third rear plate (113) is provided with a flow path communicating with the fifth heat transfer tube (71) of the fifth heat exchange section (70) or the sixth heat transfer tube (76) of the sixth heat exchange section (75). The third rear plate (113) is also provided with circular through-holes corresponding to the fifth heat transfer tube (71) of the fifth heat exchange section (70) and the sixth heat transfer tube (76) of the sixth heat exchange section (75).

[0144] (7-4) Fourth Rear Plate As shown in Fig. 10 , the fourth rear plate (114) is formed with a plurality of fifth flow paths (125) and one third connecting flow path (133). Like the fifth flow paths (125) of the second rear plate (112), the fifth flow paths (125) are in communication with the corresponding two fifth heat transfer tubes (71) and allow the refrigerant to flow between the corresponding two fifth heat transfer tubes (71). Like the third connecting flow path (133) of the second rear plate (112), the third connecting flow path (133) is in communication with the corresponding fifth heat transfer tube (71) and sixth heat transfer tube (76) and allows the refrigerant to flow between the corresponding fifth heat transfer tube (71) and sixth heat transfer tube (76).

[0145] The fourth rear plate (114) is formed with a flow path communicating with the fifth heat transfer tube (71) of the fifth heat exchange section (70) or the sixth heat transfer tube (76) of the sixth heat exchange section (75).

[0146] (7-5) Fifth Rear Plate The fifth rear plate (115) covers the flow passages formed inside the rear plate stack (110). As shown in FIG. 7 , one end of the second internal pipe (162) and one end of the gas relay pipe (163) are connected to the fifth rear plate (115). The second internal pipe (162) and the gas relay pipe (163) are joined to the fifth rear plate (115) by brazing. The second internal pipe (162) and the gas relay pipe (163) are in communication with the flow passages formed inside the rear plate stack (110).

[0147] (8) Connecting Pipe Section As described above, the connecting pipe section (135) is provided on the first front plate (101) of the front plate stack (100) and the first rear plate (111) of the rear plate stack (110). Here, the structure of the connecting pipe section (135) provided on the first front plate (101) will be described. The structure of the connecting pipe section (135) provided on the first rear plate (111) is the same as the structure of the connecting pipe section (135) provided on the first front plate (101), and therefore, description thereof will be omitted.

[0148] The connecting pipe portion (135) joined to the first heat transfer pipe (51) will be described with reference to Fig. 11. The structures of the connecting pipe portions (135) joined to the second heat transfer pipe (56), the third heat transfer pipe (61), and the fourth heat transfer pipe (66) are the same as the structure of the connecting pipe portion (135) joined to the first heat transfer pipe (51), and therefore, description thereof will be omitted.

[0149] As described above, the connecting pipe portion (135) is a short, circular tubular member. The connecting pipe portion (135) has one end portion which is a large-diameter end portion (135a) and the other end portion which is a small-diameter end portion (135b). The large-diameter end portion (135a) is a portion including the base end of the connecting pipe portion (135). The small-diameter end portion (135b) is a portion including the protruding end of the connecting pipe portion (135). The outer diameter of the small-diameter end portion (135b) is smaller than the outer diameter of the large-diameter end portion (135a). The inner diameter of the small-diameter end portion (135b) is smaller than the inner diameter of the large-diameter end portion (135a).

[0150] The open end of the first heat transfer tube (51) is flared. The inner diameter of the open end of the first heat transfer tube (51) is larger than the inner diameter of a portion of the first heat transfer tube (51) that passes through the first fin (52). The open ends of the second heat transfer tube (56), the third heat transfer tube (61), the fourth heat transfer tube (66), the fifth heat transfer tube (71), and the sixth heat transfer tube (76) are also flared.

[0151] The small diameter end (135b) of the connecting pipe portion (135) is inserted into the open end of the first heat transfer pipe (51). The connecting pipe portion (135) is joined to the first heat transfer pipe (51) by brazing. The large diameter end (135a) of the connecting pipe portion (135) is inserted into a through-hole formed in the first front plate (101). The connecting pipe portion (135) is joined to the first front plate (101) by brazing. As described above, the connecting pipe portion (135) may be formed seamlessly and integrally with the first front plate (101). The flow paths (121, 131) formed inside the front plate stack (100) communicate with the first heat transfer pipe (51) via the connecting pipe portion (135).

[0152] (9) Operation The air conditioner (10) performs cooling operation, heating operation, and dehumidifying operation.

[0153] (9-1) Cooling Operation In 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 Figure 1), appropriately adjusts the opening of the outdoor expansion valve (23), and fully opens the indoor expansion valve (160).

[0154] 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.

[0155] 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).

[0156] In the heat exchanger unit (150), the refrigerant that has flowed into the liquid relay pipe (164) flows into the front plate stack (100) of the front heat exchange section (40A). In the front heat exchange section (40A), the refrigerant absorbs heat from indoor air while passing through the heat transfer tubes (51, 56, 61, 66) of the heat exchange sections (50, 55, 60, 65). Thereafter, the refrigerant passes through the front plate stack (100) and flows into the first internal pipe (161), and then passes through the indoor expansion valve (160) and the second internal pipe (162) to flow into the rear plate stack (110) of the rear heat exchange section (40B). In the rear heat exchange section (40B), the refrigerant absorbs heat from indoor air while passing through the heat transfer tubes (71, 76) of the heat exchange sections (70, 75). Thereafter, the refrigerant passes through the rear plate stack (110), flows into the gas relay pipe (163), and then flows out of the heat exchanger unit (150).

[0157] (9-2) Heating Operation In 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 shown by the dashed line in Figure 1), adjusts the opening of the outdoor expansion valve (23) to a predetermined opening, and fully opens the indoor expansion valve (160).

[0158] 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.

[0159] 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).

[0160] In the heat exchanger unit (150), the refrigerant that has flowed into the gas relay pipe (163) flows into the rear plate stack (110) of the rear heat exchange section (40B). In the rear heat exchange section (40B), the refrigerant dissipates heat to the room air while passing through the heat transfer tubes (71, 76) of the heat exchange sections (70, 75). Thereafter, the refrigerant passes through the rear plate stack (110) and flows into the second internal pipe (162), and then passes through the indoor expansion valve (160) and the first internal pipe (161) to flow into the front plate stack (100) of the front heat exchange section (40A). In the front heat exchange section (40A), the refrigerant dissipates heat to the room air while passing through the heat transfer tubes (51, 56, 61, 66) of the heat exchange sections (50, 55, 60, 65). Thereafter, the refrigerant passes through the front plate stack (100), flows into the liquid relay pipe (164), and then flows out of the heat exchanger unit (150).

[0161] (9-3) Dehumidifying 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 apertures of the outdoor expansion valve (23) and the indoor expansion valve (160).

[0162] During dehumidification 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.

[0163] The indoor unit (30) draws room air from the indoor space (I) into the air passage (P) through the air 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 air dehumidified in this manner is supplied to the indoor space (I) through the air outlet (34).

[0164] In the heat exchanger unit (150), the refrigerant that has flowed into the liquid relay pipe (164) flows into the front plate stack (100) of the front heat exchange section (40A). In the front heat exchange section (40A), the refrigerant dissipates heat to the indoor air while passing through the heat transfer tubes (51, 56, 61, 66) of the heat exchange sections (50, 55, 60, 65). Thereafter, the refrigerant passes through the front plate stack (100) and flows into the first internal pipe (161). After being reduced in pressure while passing through the indoor expansion valve (160), the refrigerant flows through the second internal pipe (162) and then flows into the rear plate stack (110) of the rear heat exchange section (40B). In the rear heat exchange section (40B), the refrigerant absorbs heat from the indoor air while passing through the heat transfer tubes (71, 76) of the heat exchange sections (70, 75). Thereafter, the refrigerant passes through the rear plate stack (110), flows into the gas relay pipe (163), and then flows out of the heat exchanger unit (150).

[0165] (10) Method for Manufacturing a Heat Exchanger Unit A method for manufacturing a heat exchanger unit will now be described. This manufacturing method includes a first step, a second step, and a third step.

[0166] (10-1) First Step The first step is a step of assembling the front heat exchange section (40A) and the front plate stack (100) together, and includes a holding step, an assembling step, and a joining step.

[0167] In the holding step, the first heat exchange section (50), the second heat exchange section (55), the third heat exchange section (60), and the fourth heat exchange section (65) constituting the front heat exchange section (40A) are held by a jig. The relative positions of the first to fourth heat exchange sections (50, 55, 60, 65) held by the jig are substantially the same as the relative positions of the first to fourth heat exchange sections (50, 55, 60, 65) in the heat exchanger unit (150) which is a completed product.

[0168] In the assembling step, the front plate stack (100) is assembled to the first to fourth heat exchange units (50, 55, 60, 65) held by the jig in the holding step. Specifically, the small diameter ends (135b) of the connecting pipe portions (135) of the front plate stack (100) are inserted into the open ends of the heat transfer tubes (51, 56, 61, 66) of the corresponding heat exchange units (50, 55, 60, 65) (see FIG. 11 ). In the assembling step, the relative positions of the first to fourth heat exchange units (50, 55, 60, 65) and the front plate stack (100) are individually fine-adjusted as necessary.

[0169] In the joining step, the first to fourth heat exchange units (50, 55, 60, 65) combined in the assembling step are joined to the front plate stack (100) by brazing. Specifically, the heat transfer tubes (51, 56, 61, 66) of the first to fourth heat exchange units (50, 55, 60, 65) are joined to the connecting pipe portion (135) of the front plate stack (100) by brazing.

[0170] (10-2) Second Step The second step is a step of assembling the rear heat exchange section (40B) and the rear plate stack (110) together, and includes a holding step, an assembling step, and a joining step.

[0171] In the holding step, the fifth heat exchange section (70) and the sixth heat exchange section (75) constituting the rear heat exchange section (40B) are held by a jig. The relative positions of the fifth and sixth heat exchange sections (70, 75) held by the jig are substantially the same as the relative positions of the fifth and sixth heat exchange sections (70, 75) in the heat exchanger unit (150) which is a completed product.

[0172] In the assembling step, the rear plate stack (110) is assembled to the fifth and sixth heat exchange sections (70, 75) held by the jigs in the holding step. Specifically, the small diameter ends (135b) of the connecting pipe sections (135) of the rear plate stack (110) are inserted into the open ends of the heat transfer tubes (71, 76) of the corresponding heat exchange sections (70, 75). In the assembling step, the relative positions of the fifth and sixth heat exchange sections (70, 75) and the rear plate stack (110) are individually fine-adjusted as necessary.

[0173] In the joining step, the fifth and sixth heat exchange units (70, 75) and the rear plate stack (110) combined in the assembling step are joined by brazing. Specifically, the heat transfer tubes (71, 76) of the fifth and sixth heat exchange units (70, 75) and the connecting pipe portion (135) of the rear plate stack (110) are joined by brazing.

[0174] (10-3) Third Step The third step is a step of attaching an indoor expansion valve (160), a gas relay pipe (163), a liquid relay pipe (164), and a retaining member (155) to the front heat exchange section (40A) and the front plate stack (100) assembled in the first step, and the rear heat exchange section (40B) and the rear plate stack (110) assembled in the second step.

[0175] The indoor expansion valve (160) is attached to the front plate stack (100) via a first internal pipe (161) and to the rear plate stack (110) via a second internal pipe (162) (see FIG. 7 ). One end of the first internal pipe (161) is joined to the indoor expansion valve (160) and the other end is joined to the front plate stack (100) by brazing. One end of the second internal pipe (162) is joined to the indoor expansion valve (160) and the other end is joined to the rear plate stack (110) by brazing.

[0176] The gas relay pipe (163) is joined to the rear plate stack (110) by brazing. The liquid relay pipe (164) is joined to the front plate stack (100) by brazing. The holding member (155) is attached to the front heat exchange section (40A) and the rear heat exchange section (40B) by fasteners such as screws.

[0177] (11) Features of the Embodiment (11-1) First Feature In the heat exchanger unit (150) of the present embodiment, both the first heat exchange section (50) and the second heat exchange section (55) are joined to the front plate stack (100).

[0178] When the first heat exchange section (50) and the second heat exchange section (55) are combined with the front plate stack (100), the relative position of the front plate stack (100) with respect to the first heat transfer tube (51) of the first heat exchange section (50) and the relative position of the front plate stack (100) with respect to the second heat transfer tube (56) of the second heat exchange section (55) can be adjusted individually. Therefore, compared to the case where "one large heat exchange section that exhibits a heat exchange capacity equivalent to the total heat exchange capacity of the first heat exchange section (50) and the second heat exchange section (55)" is combined with the front plate stack (100), it is easier to adjust the relative positions of the first heat transfer tube (51) of the first heat exchange section (50) and the second heat transfer tube (56) of the second heat exchange section (55) with the front plate stack (100).

[0179] Therefore, according to this embodiment, the time required to combine the first heat exchange section (50) and the second heat exchange section (55) with the front plate stack (100) can be shortened, and the time required to manufacture the heat exchanger unit (150) can be shortened.

[0180] (11-2) Second Feature In the heat exchanger unit (150) of this embodiment, a first flow path (121), a second flow path (122), and a connecting flow path (131) are formed inside the front plate stack (100). Therefore, the connection between the first heat transfer tubes (51), the connection between the second heat transfer tubes (56), and the connection between the first heat transfer tubes (51) and the second heat transfer tubes (56) are realized by the single front plate stack (100).

[0181] (11-3) Third Feature In the heat exchanger unit (150) of this embodiment, a first flow path (121), a second flow path (122), and a third flow path (123) are formed inside the front plate stack (100). Therefore, the connection between the first heat transfer tubes (51), the connection between the second heat transfer tubes (56), and the connection between the third heat transfer tubes (61) are realized by the single front plate stack (100).

[0182] (11-4) Fourth Feature In the heat exchanger unit (150) of the present embodiment, a large diameter end (135a) and a small diameter end (135b) are formed in each connecting pipe portion (135). The large diameter end (135a) having a relatively large diameter is joined to the first front plate (101) or the first rear plate (111), and the small diameter end (135b) having a relatively small diameter is joined to the corresponding heat transfer tube (51, 56, 61, 66, 71, 76).

[0183] The refrigerant flowing from the heat transfer tubes (51, 56, 61, 66, 71, 76) into the connecting pipe portion (135) flows from the small diameter end (135b) toward the large diameter end (135a) and then flows into the flow paths (121-126, 131-133) formed in the main body portion (106, 116) of the plate stack (100, 110). This reduces pressure loss of the refrigerant while it flows out of the heat transfer tubes (51, 56, 61, 66, 71, 76) and into the flow paths (121-126, 131-133) in the main body portion (106, 116).

[0184] (11-5) Fifth Feature In the front heat exchange section (40A) of this embodiment, one end of each of the first heat exchange section (50), the second heat exchange section (55), the third heat exchange section (60), and the fourth heat exchange section (65) is held by the front plate stack (100), and the other end of each of the first heat exchange section (50), the second heat exchange section (55), the third heat exchange section (60), and the fourth heat exchange section (65) is held by the holding member (155). In the rear heat exchange section (40B) of this embodiment, one end of each of the fifth heat exchange section (70) and the sixth heat exchange section (75) is held by the rear plate stack (110), and the other end of each of the fifth heat exchange section (70) and the sixth heat exchange section (75) is held by the holding member (155). Therefore, according to this embodiment, the relative positions of the heat exchange sections (50, 55, 60, 65, 70, 75) constituting the heat exchanger unit (150) can be reliably maintained.

[0185] (11-6) Sixth Feature In the indoor unit (30) of this embodiment, the heat exchanger unit (150) is disposed in the casing (31) with the first air inlet surface (54) of the first heat exchange section (50) facing upward and the second air inlet surface (59) of the second heat exchange section (55) facing downward. Furthermore, in the front heat exchange section (40A) of this embodiment, the lower ends of the first fins (52) of the first heat exchange section (50) are aligned along the long sides (57b) of the second fins (57) on the air outlet side of the second fins (57) of the second heat exchange section (55). Therefore, condensed water generated on the surfaces of the first fins (52) can be reliably transferred to the second fins (57). As a result, scattering of the condensed water generated on the surfaces of the first fins (52) can be suppressed.

[0186] (11-7) Seventh Feature In the front heat exchange section (40A) of the heat exchanger unit (150) of this embodiment, the shapes and relative positions of the first heat exchange section (50) and the second heat exchange section (55) are set so that the third distance D3 is equal to or less than the first distance D1 and the third distance D3 is equal to or less than the second distance D2. This allows the front heat exchange section (40A) to have a low vertical height, thereby enabling the size of the casing (31) that houses the heat exchanger unit (150).

[0187] (11-8) Eighth Feature In the indoor unit (30) of this embodiment, the air inlet (33) is formed in an upper part of the casing (31). Therefore, in the front heat exchange section (40A) of the indoor heat exchanger (40), the flow rate of air passing through the first heat exchange section (50) relatively close to the air inlet (33) is greater than the flow rate of air passing through the second heat exchange section (55) relatively far from the air inlet (33).

[0188] On the other hand, in the heat exchanger unit (150) of this embodiment, the number of first heat transfer pipes (51) included in the first heat exchange section (50) is greater than the number of second heat transfer pipes (56) included in the second heat exchange section (55). Therefore, the heat exchange capacity of the first heat exchange section (50), through which the flow rate of air passing therethrough is relatively high, is greater than the heat exchange capacity of the second heat exchange section (55), through which the flow rate of air passing therethrough is relatively low.

[0189] Therefore, according to this embodiment, by increasing the heat exchange capacity of the first heat exchange section (50), through which the flow rate of air passing through is relatively large, the heat exchange capacity of the entire heat exchanger unit (150) can be improved.

[0190] (11-9) Ninth Feature In the indoor unit (30) of this embodiment, the first heat exchange section (50) of the front heat exchange section (40A) is disposed in the casing (31) in an orientation such that the angle between the long sides (52a, 52b) of the upwardly facing first fins (52) and the vertical direction is 30° or more. This allows the first heat exchange section (50) to be increased in size without increasing the height of the casing (31). As a result, the heat exchange capacity of the entire heat exchanger unit (150) can be improved without increasing the size of the casing (31) of the indoor unit (30).

[0191] (11-10) Tenth Feature In the indoor unit (30) of the present embodiment, the first heat exchange section (50) of the front heat exchange section (40A) is provided in the casing (31) in an orientation such that the angle formed between the long sides (52a, 52b) of the upwardly facing first fins (52) and the vertical direction is 60° or less. Therefore, condensed water generated on the surfaces of the first fins (52) can flow along the surfaces of the first fins (52) to reach the lower ends of the first fins (52), thereby preventing the condensed water generated on the surfaces of the first fins (52) from scattering.

[0192] (11-11) Eleventh Feature In the heat exchanger unit (150) of this embodiment, the fin pitch FP1 of the first fins (52) in the first heat exchange section (50) is equal to the fin pitch FP2 of the second fins (57) in the second heat exchange section (55) (FP1=FP2). Therefore, a corresponding second fin (57) is disposed below each first fin (52) in the first heat exchange section (50). Condensed water generated on the surface of the first fin (52) flows down from the lower end of the first fin (52) to the corresponding second fin (57) and then further flows down along the second fin (57). Therefore, this embodiment can suppress scattering of condensed water generated on the surface of the first fin (52).

[0193] (11-12) Twelfth Feature In the heat exchanger unit (150) of this embodiment, the effective length EL1 of the first heat exchange section (50) is equal to the effective length EL2 of the second heat exchange section (55) (EL1=EL2). Therefore, all of the condensed water flowing down from the first heat exchange section (50) is received by the second heat exchange section (55). Therefore, this embodiment can prevent the condensed water generated on the surfaces of the first fins (52) from scattering.

[0194] (12) Modifications of the Embodiment The heat exchanger unit (150) of the present embodiment can be modified as described below.

[0195] (12-1) First Modification In the front heat exchange section (40A) of the heat exchanger unit (150) of this embodiment, the first heat exchange section (50) and the second heat exchange section (55) may be arranged as shown in FIG. 12.

[0196] 12 , the upper short side (57c) of the second fin (57) of the second heat exchange section (55) is aligned along the long side (52b) on the air outlet side of the first fin (52) of the first heat exchange section (50). In addition, in this heat exchanger unit (150), the air outlet side long side (67b) of the fourth fin (67) of the fourth heat exchange section (65) is aligned along both the lower short side (52d) of the first fin (52) of the first heat exchange section (50) and the air inlet side long side (57a) of the second fin (57) of the second heat exchange section (55).

[0197] In the heat exchanger unit (150) of this modified example, the condensed water flowing down from the first fins (52) of the first heat exchange section (50) is received by the fourth fins (67) of the fourth heat exchange section (65).

[0198] (12-2) Second Modification As shown in FIG. 13, in the front heat exchange section (40A) of the heat exchanger unit (150) of this embodiment, the shapes and relative positions of the first heat exchange section (50) and the second heat exchange section (55) may be set so that the third distance D3 is equal to or greater than the first distance D1 and the third distance D3 is equal to or greater than the second distance D2.

[0199] The first distance D1 is the distance between the central axes of the two closest first heat transfer tubes (51). The second distance D2 is the distance between the central axes of the two closest second heat transfer tubes (56). The third distance D3 is the distance between the central axes of the closest first heat transfer tube (51) and second heat transfer tube (56).

[0200] In this modification, the shortest distance from the first heat transfer tube (51) of the first heat exchange section (50) to the second heat transfer tube (56) of the second heat exchange section (55) is equal to or greater than the shortest distance between the first heat transfer tubes (51) in the first heat exchange section (50) and equal to or greater than the shortest distance between the second heat transfer tubes (56) in the second heat exchange section (55). Therefore, when the first heat exchange section (50) and the second heat exchange section (55) are combined with the front plate stack (100), sufficient space is ensured for brazing the first heat transfer tube (51) to the connecting pipe section (135) and brazing the second heat transfer tube (56) to the connecting pipe section (135). Therefore, this modification reduces the possibility of poor bonding between the first heat transfer tube (51) or the second heat transfer tube (56) and the connecting pipe section (135).

[0201] (12-3) Third Modification As shown in FIG. 14, in the heat exchanger unit (150) of this embodiment, the heat transfer tubes (51, 56, 61, 66, 71, 78) forming the heat exchange sections (50, 55, 60, 65, 70, 75) may be so-called flat tubes.

[0202] As shown in FIG. 15 , the flat tubes constituting the heat transfer tubes (51, 56, 61, 66, 71, 78) of this modified example have an oval or elliptical cross-sectional shape. The flat tubes constituting the heat transfer tubes (51, 56, 61, 66, 71, 78) of this modified example are formed in a straight pipe shape. The flat tubes constituting the heat transfer tubes (51, 56, 61, 66, 71, 78) of this modified example have a plurality of refrigerant flow paths formed therein. Each refrigerant flow path is a straight flow path extending from one end of the flat tube to the other end. Each refrigerant flow path opens at one end face and the other end face of the flat tube. The flat tubes constituting the heat transfer tubes (51, 56, 61, 66, 71, 78) of this modified example are made of aluminum or an aluminum alloy.

[0203] The heat transfer tubes (51, 56, 61, 66) of the first to fourth heat exchange sections (50, 55, 60, 65) constituting the front heat exchange section (40A) have one end joined to the front plate stack (100) and the other end joined to a header collecting pipe. In each of the first to fourth heat exchange sections (50, 55, 60, 65), the heat transfer tubes (51, 56, 61, 66) communicate with the other heat transfer tubes (51, 56, 61, 66) via the internal space of the header collecting pipe.

[0204] The heat transfer tubes (71, 76) of the fifth and sixth heat exchange sections (70, 75) constituting the rear heat exchange section (40B) are joined at one end to the rear plate stack (110) and at the other end to a header collecting pipe. In each of the fifth and sixth heat exchange sections (70, 75), the heat transfer tubes (71, 76) communicate with each other through the internal space of the header collecting pipe.

[0205] A method for manufacturing the heat exchanger unit (150) of this modified example will be described. This manufacturing method includes a first step, a second step, and a third step. Note that the manufacturing method described below can also be applied to the "heat exchanger unit (150) having heat transfer tubes (51, 56, 61, 66, 71, 76) with circular cross sections" shown in Figures 6, 12, and 13.

[0206] (12-3-1) First Step The first step is a step of assembling the front heat exchange section (40A) and the front plate stack (100) together, and includes a combining step and a joining step.

[0207] In the assembling step, the first to fourth heat exchange sections (50, 55, 60, 65) constituting the front heat exchange section (40A) are sequentially assembled to the front plate stack (100) one by one. In this assembling step, the front plate stack (100) is held by a holder or the like. Then, for example, the first heat exchange section (50), the second heat exchange section (55), the third heat exchange section (60), and the fourth heat exchange section (65) are sequentially assembled to the held front plate stack (100).

[0208] Specifically, in this example, the end of the first heat transfer tube (51) of the first heat exchange section (50) is first inserted into the front plate stack (100), then the end of the second heat transfer tube (56) of the second heat exchange section (55) is inserted, then the end of the third heat transfer tube (61) of the third heat exchange section (60) is inserted, and then the end of the fourth heat transfer tube (66) of the fourth heat exchange section (65) is inserted. In the process of assembling each of the first to fourth heat exchange sections (50, 55, 60, 65) with the front plate stack (100), the relative positions of the first to fourth heat exchange sections (50, 55, 60, 65) and the front plate stack (100) are individually fine-adjusted as necessary.

[0209] The order in which the first to fourth heat exchange sections (50, 55, 60, 65) are combined with the front plate stack (100) is not limited to the above example. Therefore, for example, the front plate stack (100) may be combined with the first heat exchange section (50), the third heat exchange section (60), the second heat exchange section (55), and the fourth heat exchange section (65) in this order, or the front plate stack (100) may be combined with the second heat exchange section (55), the first heat exchange section (50), the fourth heat exchange section (65), and the third heat exchange section (60) in this order.

[0210] In the joining step, the first to fourth heat exchange units (50, 55, 60, 65) combined in the assembling step are joined to the front plate stack (100) by brazing. Specifically, the heat transfer tubes (51, 56, 61, 66) of the first to fourth heat exchange units (50, 55, 60, 65) are joined to the front plate stack (100) by brazing.

[0211] (12-3-2) Second Step The second step is a step of assembling the rear heat exchange section (40B) and the rear plate stack (110) together, and includes a combining step and a joining step.

[0212] In the assembling step, the fifth and sixth heat exchange sections (70, 75) constituting the rear heat exchange section (40B) are sequentially assembled to the rear plate stack (110). In this assembling step, the rear plate stack (110) is held by a holder or the like. Then, for example, the fifth heat exchange section (70) and the sixth heat exchange section (75) are sequentially assembled to the held rear plate stack (110).

[0213] Specifically, in this example, the end of the fifth heat transfer tube (71) of the fifth heat exchange section (70) is first inserted into the rear plate stack (110), and then the end of the sixth heat transfer tube (76) of the sixth heat exchange section (75) is inserted into the rear plate stack (110). In the process of assembling each of the fifth and sixth heat exchange sections (70, 75) with the rear plate stack (110), the relative positions of the fifth and sixth heat exchange sections (70, 75) and the rear plate stack (110) are individually fine-adjusted as necessary.

[0214] The order in which the fifth and sixth heat exchange units (70, 75) are combined with the rear plate stack (110) is not limited to the above example, and therefore the sixth heat exchange unit (75) and the fifth heat exchange unit (70) may be combined with the rear plate stack (110) in this order.

[0215] In the joining step, the fifth and sixth heat exchange units (70, 75) and the rear plate stack (110) combined in the assembling step are joined by brazing. Specifically, the heat transfer tubes (71, 76) of the fifth and sixth heat exchange units (70, 75) and the rear plate stack (110) are joined by brazing.

[0216] (12-3-3) Third Step The third step is a step of attaching an indoor expansion valve (160), a gas relay pipe (163), a liquid relay pipe (164), and a retaining member (155) to the front heat exchange section (40A) and the front plate stack (100) assembled in the first step, and the rear heat exchange section (40B) and the rear plate stack (110) assembled in the second step.

[0217] The indoor expansion valve (160) is attached to the front plate stack (100) via a first internal pipe (161) and to the rear plate stack (110) via a second internal pipe (162) (see FIG. 7 ). One end of the first internal pipe (161) is joined to the indoor expansion valve (160) and the other end is joined to the front plate stack (100) by brazing. One end of the second internal pipe (162) is joined to the indoor expansion valve (160) and the other end is joined to the rear plate stack (110) by brazing.

[0218] The gas relay pipe (163) is joined to the rear plate stack (110) by brazing. The liquid relay pipe (164) is joined to the front plate stack (100) by brazing. The holding member (155) is attached to the front heat exchange section (40A) and the rear heat exchange section (40B) by fasteners such as screws.

[0219] (12-4) Fourth Modification In the heat exchanger unit (150) of the above embodiment, a plate stack (100, 110) formed by stacking a plurality of plates (101-105, 111-115) is provided as a plate structure having flow paths (121, 122, ...) formed therein. This plate structure may be a single thick plate-like member having the flow paths (121, 122, ...) formed therein. The plate structure of this modification, which is a single thick plate-like member, is manufactured by sintering metal powder using, for example, a 3D printer.

[0220] (12-5) Fifth Modification In the indoor unit (30) of the above embodiment, the heat exchanger unit (150) may be installed inside the casing in an orientation in which the first air inlet surface (54) of the first heat exchange section (50) and the second air inlet surface (59) of the second heat exchange section (55) face the rear side of the casing (31), and the fifth air inlet surface (74) of the fifth heat exchange section (70) faces the front side of the casing (31).

[0221] (12-6) Sixth Modification In the air conditioner (10) of the above embodiment, the outdoor heat exchanger (22) provided in the outdoor unit (20) may be configured by the heat exchanger unit (150) of this embodiment.

[0222] Although the embodiments and modifications have been described above, it will be understood that various modifications in form and detail are possible without departing from the spirit and scope of the claims. Furthermore, elements of the above embodiments, modifications, and other embodiments may be combined or substituted as appropriate. Furthermore, the terms "first," "second," "third," etc. in the specification and claims are used to distinguish between terms to which these terms are attached, and do not limit the number or order of those terms.

[0223] INDUSTRIAL APPLICABILITY As described above, the present disclosure is useful for a heat exchanger unit, an air conditioning indoor unit, a refrigeration cycle device, and a method for manufacturing a heat exchanger unit.

[0224] 10 air conditioner (refrigeration cycle device) 11 refrigerant circuit 30 indoor unit (air conditioning indoor unit) 31 casing 50 first heat exchange section 51 first heat transfer tube 52 first fin 52a long side (air inlet side) 52b long side (air outlet side) 53 first fin group 54 first air inlet surface (air inlet surface) 55 second heat exchange section 56 second heat transfer tube 57 second fin 57a ​​long side (air inlet side) 57b long side (air outlet side) 58 second fin group 59 second air inlet surface (air inlet surface) 60 third heat exchange section 61 third heat transfer tube 62 third fin 100 front plate stack (plate structure) 106 main body 121 first flow path 122 second flow path 123 third flow path 131 first connecting flow path (connecting flow path) 135 connecting pipe portion 150 heat exchanger unit 155 holding member

Claims

1. A heat exchanger unit (150) for exchanging heat between air and a refrigerant, comprising: a first heat exchange section (50) having a plurality of first fins (52) and a plurality of first heat transfer tubes (51); a second heat exchange section (55) having a plurality of second fins (57) and a plurality of second heat transfer tubes (56); and a plate structure (100) joined to the first heat transfer tubes (51) and the second heat transfer tubes (56), and having formed therein a first flow path (121) connecting the first heat transfer tubes (51) to each other, and a second flow path (122) connecting the second heat transfer tubes (56) to each other.

2. The heat exchanger unit according to claim 1, wherein a connecting passage (131) connecting the first heat transfer pipe (51) and the second heat transfer pipe (56) is formed inside the plate structure (100).

3. The heat exchanger unit according to claim 1 or 2, wherein each of the plurality of first fins (52) is formed in a plate shape having a pair of linear long sides (52a, 52b) parallel to each other, and each of the plurality of first heat transfer tubes (51) penetrates the plurality of first fins (52) arranged in a row, while each of the plurality of second fins (57) is formed in a plate shape having a pair of linear long sides (57a, 57b) parallel to each other, and each of the plurality of second heat transfer tubes (56) penetrates the plurality of second fins (57) arranged in a row.

4. The heat exchanger unit according to any one of claims 1 to 3, further comprising a third heat exchange section (60) having a plurality of third fins (62) and a plurality of third heat transfer tubes (61), the plate structure (100) is connected to the third heat transfer tubes (61), and a third flow path (123) connecting the third heat transfer tubes (61) to each other is formed inside the plate structure (100).

5. A heat exchanger unit as claimed in any one of claims 1 to 4, wherein the plate structure (100) comprises: a plate-shaped main body portion (106) having the first flow path (121) and the second flow path (122) formed therein; and a plurality of connecting pipe portions (135) protruding from the main body portion (106), each having a base end connected to the first flow path (121) or the second flow path (122) and each having a tip end connected to the first heat transfer tube (51) or the second heat transfer tube (56), wherein the diameter of the tip of each of the plurality of connecting pipe portions (135) is smaller than the diameter of the base end.

6. In the first heat exchange section (50), a plurality of the first fins (52) arranged in a row form a first fin group (53), and in the second heat exchange section (55), a plurality of the second fins (57) arranged in a row form a second fin group (58), the plate structure (100) is provided on one end side of the first fin group (53) in the arrangement direction of the first fins (52) and on one end side of the second fin group (58) in the arrangement direction of the second fins (57), and the heat exchanger unit (150) is provided on the other end side of the first fin group (53) in the arrangement direction of the first fins (52) and on the other end side of the second fin group (58) in the arrangement direction of the second fins (57), and includes a holding member (155) that holds the first heat exchange section (50) and the second heat exchange section (55). A heat exchanger unit according to any one of the preceding claims.

7. An air-conditioning indoor unit comprising: a heat exchanger unit (150) according to claim 3; and a casing (31) housing the heat exchanger unit (150), wherein the first heat exchange section (50) is disposed above the second heat exchange section (55) in an orientation in which an angle formed between the long sides (52a, 52b) of the first fin (52) and the long sides (57a, 57b) of the second fin (57) is less than 180°.

8. The air conditioning indoor unit according to claim 7, wherein the first heat exchange section (50) is provided with a long side (52a) of the air inlet side of the first fin (52) facing upward, and the second heat exchange section (55) is provided with a long side (57a) of the air inlet side of the second fin (57) facing downward.

9. The air conditioning indoor unit according to claim 8, wherein a lower end of the first fin (52) of the first heat exchange section (50) is aligned along a long side (57b) on the air outlet side of the second fin (57) of the second heat exchange section (55).

10. The air conditioning indoor unit according to claim 9, wherein a connecting flow path (131a) connecting the first heat transfer tube (51) and the second heat transfer tube (56) is formed inside the plate structure (100), the first heat transfer tube (51) communicating with the connecting flow path (131a) is one of the plurality of first heat transfer tubes (51) aligned in a row along the long side (52a) of the air inflow side of the first fin (52), and the second heat transfer tube (56) communicating with the connecting flow path (131a) is one of the plurality of second heat transfer tubes (56) aligned in a row along the long side (57b) of the air outflow side of the second fin (57).

11. The air conditioning indoor unit according to claim 9 or 10, wherein a distance between the respective central axes of two of the first heat transfer tubes (51) that are closest to each other is a first distance, a distance between the respective central axes of two of the second heat transfer tubes (56) that are closest to each other is a second distance, and a distance between the respective central axes of the first heat transfer tube (51) and the second heat transfer tube (56) that are closest to each other is a third distance, and the third distance is not more than the first distance and not more than the second distance.

12. The air conditioning indoor unit according to any one of claims 8 to 11, wherein the number of the first heat transfer tubes (51) in the first heat exchange section (50) is greater than the number of the second heat transfer tubes (56) in the second heat exchange section (55).

13. The air conditioning indoor unit according to any one of claims 8 to 12, wherein an angle between the long sides (52a, 52b) of the first fin (52) of the first heat exchange section (50) and the vertical direction is equal to or greater than 30°.

14. The air conditioning indoor unit according to any one of claims 8 to 13, wherein an angle between a long side (52a, 52b) of the first fin (52) of the first heat exchange section (50) and the vertical direction is equal to or less than 60°.

15. The air conditioning indoor unit according to any one of claims 8 to 14, wherein the spacing between the multiple first fins (52) in the first heat exchange section (50) is equal to the spacing between the multiple second fins (57) in the second heat exchange section (55).

16. The air conditioning indoor unit according to any one of claims 8 to 15, wherein the distance from the first fin (52) located at one end in the arrangement direction of the plurality of first fins (52) to the first fin (52) located at the other end is the effective length of the first heat exchange section (50), the distance from the second fin (57) located at one end in the arrangement direction of the plurality of second fins (57) to the second fin (57) located at the other end is the effective length of the second heat exchange section (55), and the effective length of the first heat exchange section (50) is equal to or less than the effective length of the second heat exchange section (55).

17. An air conditioning indoor unit as described in any one of claims 7 to 16, wherein the heat exchanger unit (150) is arranged in a position such that air inlet surfaces (54, 59) of the first heat exchange section (50) and the second heat exchange section (55) face toward the front or rear of the casing (31).

18. A refrigeration cycle device comprising a refrigerant circuit (11) to which the heat exchanger unit (150) according to any one of claims 1 to 6 is connected.

19. A method for manufacturing a heat exchanger unit (150) for exchanging heat between air and a refrigerant, comprising a plurality of heat exchange sections each having fins and heat transfer tubes, and a plate structure (100) joined to the heat transfer tubes of the plurality of heat exchange sections, the plurality of heat exchange sections including a first heat exchange section (50) having a plurality of first fins (52) and first heat transfer tubes (51) and a second heat exchange section (55) having a plurality of second fins (57) and second heat transfer tubes (56), a refrigerant flow path formed inside the plate structure (100) including a first flow path (121) connecting the first heat transfer tubes (51) and a second flow path (122) connecting the second heat transfer tubes (56), a holding step of holding the plurality of heat exchange sections such that the relative positions of the plurality of heat exchange sections are the same as the relative positions of the plurality of heat exchange sections in the heat exchanger unit (150) which is a finished product, a joining step of joining the heat transfer tubes of the heat exchange units combined in the combining step to the plate structure (100) by brazing.

20. A method for manufacturing a heat exchanger unit (150) for exchanging heat between air and a refrigerant, comprising a plurality of heat exchange sections each having fins and a heat transfer tube, and a plate structure (100) joined to the heat transfer tubes of the plurality of heat exchange sections, the plurality of heat exchange sections including a first heat exchange section (50) having a plurality of first fins (52) and first heat transfer tubes (51) and a second heat exchange section (55) having a plurality of second fins (57) and second heat transfer tubes (56), a refrigerant flow path formed inside the plate structure (100) including a first flow path (121) connecting the first heat transfer tubes (51) and a second flow path (122) connecting the second heat transfer tubes (56), and a combination step of combining the plurality of heat exchange sections one by one with the plate structure (100); a joining step of joining the heat transfer tubes of the plurality of heat exchange sections combined in the combining step to the plate structure (100) by brazing.

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