Method for manufacturing indoor units and heat exchangers for air conditioners

Abstract

This suppresses the water splashing phenomenon caused by condensed water being scattered from the indoor unit. [Solution] The indoor unit (120) is divided into a first part (120a), a second part (120b), and a third part (120c). The third part (120c) includes the entire outlet (123). The fin group (20) of the heat exchanger (10) is provided across the first part (120a), the third part (120c), and the second part (120b) of the indoor unit (120). The part of the fin group (20) located in the third part (120c) is the intermediate part (23). A hydrophilic layer (40) is formed on the entire surface of the intermediate part (23).

Description

[Technical Field]

[0001] The present disclosure relates to an indoor unit of an air conditioner and a method for manufacturing a heat exchanger. [Background Art]

[0002] Patent Document 1 discloses an indoor unit for an air conditioner. An indoor heat exchanger is accommodated in the indoor unit. During a cooling operation of the air conditioner, the indoor heat exchanger functions as an evaporator, and water vapor in the air condenses on the fins of the indoor heat exchanger. Condensed water generated on the fins flows down along the surfaces of the fins and is discharged to the outside of the outdoor unit.

[0003] During a cooling operation, a phenomenon (a so-called water splash phenomenon) may occur in which part of the condensed water generated in the indoor heat exchanger peels off from the fins and is blown out into the indoor space together with the air. To prevent the water splash phenomenon, a countermeasure of forming a hydrophilic layer on the surfaces of the fins is taken. [Prior Art Literature] [Patent Literature]

[0004] [Patent Document 1] Japanese Unexamined Patent Publication No. 2008-224200 [Summary of the Invention] [Problem to be Solved by the Invention]

[0005] When manufacturing heat exchangers with a hydrophilic layer, fins are often formed by pressing metal sheets with a pre-formed hydrophilic layer, and then these fins are combined with heat transfer tubes. After that, refrigerant tubes are joined to the heat transfer tubes by brazing. When manufacturing heat exchangers using this process, the joint between the heat transfer tubes and refrigerant tubes is heated during the brazing process. As a result, the hydrophilic layer on fins located near the joint between the heat transfer tubes and refrigerant tubes may carbonize and disappear. Consequently, condensed water may be scattered from the parts of the indoor heat exchanger where the hydrophilic layer has disappeared and blown into the room with the air, making it impossible to prevent water splashing.

[0006] The purpose of this disclosure is to suppress the water splashing phenomenon in which condensed water is scattered from the indoor unit. [Means for solving the problem]

[0007] A first aspect of the present disclosure is an indoor unit (120) of an air conditioner comprising a heat exchanger (10) for exchanging heat between air and a refrigerant, a fan (125), and a casing (121) housing the heat exchanger (10) and the fan (125), wherein the left-right direction when the indoor unit (120) is viewed from the front is the reference direction, and the casing (121) has an outlet (123) extending in the reference direction, and the heat exchanger (10) comprises a fin group (20) consisting of a plurality of fins (30) arranged in the reference direction, a heat transfer tube (50), and a refrigerant pipe (55) connected to the heat transfer tube (50). Of the indoor unit (120), the portion to the right of the air outlet (123) when the indoor unit (120) is viewed from the front is the first portion (120a), and the portion to the left of the air outlet (123) when the indoor unit (120) is viewed from the front is the second portion (120b), and the portion of the indoor unit (120) located between the first portion (120a) and the second portion (120b) is the air outlet (1 The portion including the entirety of 23) is the third portion (120c), and the fin group (20) is provided across the first portion (120a), the third portion (120c), and the second portion (120b) of the indoor unit (120). The portion of the fin group (20) located in the third portion (120c) of the indoor unit (120) is the intermediate portion (23), and a hydrophilic layer (40) made of a hydrophilic material is formed on the entire surface of the intermediate portion (23).

[0008] In the first embodiment, the intermediate portion (23) of the fin group (20) is located in the third portion (120c) of the indoor unit (120). The third portion (120c) of the indoor unit (120) includes the entire outlet (123). Therefore, if condensed water is scattered from the intermediate portion (23) of the fin group (20), there is a high possibility that the scattered condensed water will be blown out of the outlet (123) along with the air. On the other hand, in the heat exchanger (10) of this embodiment, a hydrophilic layer (40) is formed on the entire surface of the intermediate portion (23) of the fin group (20). Therefore, the scattering of condensed water from the intermediate portion (23) of the fin group (20) is suppressed, and the "water splashing phenomenon" in which condensed water is scattered from the indoor unit (120) is suppressed.

[0009] A second aspect of this disclosure is that, in the first aspect, the hydrophilic layer (40) is formed on the entire surface of the fin group (20).

[0010] In the second embodiment, a hydrophilic layer (40) is formed over the entire fin group (20), including the intermediate portion (23).

[0011] A third aspect of this disclosure is that, in the first aspect described above, the portion of the fin group (20) located in the first portion (120a) of the indoor unit (120) is the right portion (21), Of the fin group (20) described above, the portion located in the second part (120b) of the indoor unit (120) described above is the left part (22), and part or all of the right part (21) and part or all of the left part (22) are non-hydrophilic regions (25) on which the hydrophilic layer (40) does not exist on the surface.

[0012] In a third embodiment, the right portion (21) and the left portion (22), which are parts of the fin group (20) other than the middle portion (23), do not have a hydrophilic layer (40) on part or all of their surfaces.

[0013] A fourth aspect of this disclosure is that, in any one of the first to third aspects described above, the material of the heat transfer tube (50) and the refrigerant tube (55) is aluminum or an aluminum alloy.

[0014] In the fourth embodiment, the material of the heat transfer tube (50) and the refrigerant tube (55) is aluminum or an aluminum alloy.

[0015] A fifth aspect of the present disclosure is, in any one of the first to fourth aspects described above, each of the plurality of fins (30) constituting the fin group (20) is formed in a plate shape having a pair of parallel long sides (31, 32), and the inclination angle of the long sides (31, 32) of the fin (30) with respect to the vertical is 30° or more and 50° or less.

[0016] In a fifth embodiment, the heat exchanger (10) is installed inside the indoor unit (120) in a position such that the inclination angle of the long sides (31,32) of the fins (30) with respect to the vertical is 30° or more and 50° or less.

[0017] A sixth aspect of this disclosure is that, in any one of the first to fifth aspects described above, the arrangement pitch of the plurality of fins (30) in the fin group (20) is 1.5 mm or less.

[0018] In the sixth embodiment, the arrangement pitch of the multiple fins (30) is set to 1.5 mm or less.

[0019] A seventh aspect of the present disclosure is, in any one of the first to sixth aspects, the heat exchanger (10) comprises auxiliary heat exchange sections (11b, 12b, 13b) for exchanging heat between air and a refrigerant, the auxiliary heat exchange sections (11b, 12b, 13b) being positioned upstream of the fin group (20) in the direction of airflow through the heat exchanger (10), and the entirety of the auxiliary heat exchange sections (11b, 12b, 13b) being a non-hydrophilic region (25) on which the hydrophilic layer (40) is not present on the surface.

[0020] In the seventh embodiment, the auxiliary heat exchange sections (11b, 12b, 13b) are positioned upstream of the fin group (20) in the direction of airflow through the heat exchanger (10). The entirety of the auxiliary heat exchange sections (11b, 12b, 13b) is a non-hydrophilic region (25). Therefore, condensed water may be scattered from the auxiliary heat exchange sections (11b, 12b, 13b). The condensed water scattered from the auxiliary heat exchange sections (11b, 12b, 13b) adheres to the fin group (20) located downstream of the auxiliary heat exchange sections (11b, 12b, 13b). Therefore, the condensed water scattered from the auxiliary heat exchange sections (11b, 12b, 13b) does not reach the outlet (123) of the indoor unit (120), and is therefore not blown into the room with the air from the outlet (123).

[0021] An eighth aspect of the present disclosure is a method for manufacturing the heat exchanger (10) included in the indoor unit (120) according to the first aspect described above, the method comprising: a first step of processing a metal plate material to form the fins (30); a second step of combining the fin group (20) consisting of the plurality of fins (30) formed in the first step with the heat transfer tubes (50); a third step of joining the refrigerant tubes (55) to the heat transfer tubes (50) combined with the fin group (20) in the second step by brazing; a fourth step of applying a raw material liquid containing a hydrophilic material to the entire intermediate portion (23) of the fin group (20) that has undergone the third step; and a fifth step of forming the hydrophilic layer (40) on the surface of the intermediate portion (23) of the fin group (20) by drying the raw material liquid applied to the fin group (20) in the fourth step.

[0022] In the eighth aspect, after the third step of performing the brazing operation, the fourth step and the fifth step for forming the hydrophilic layer (40) are performed. Therefore, even when the refrigerant tubes (55) are joined to the heat transfer tubes (50) by brazing, the hydrophilic layer (40) is formed on the entire intermediate portion (23) of the fin group (20).

[0023] A ninth aspect of the present disclosure is, according to the eighth aspect described above, in the fourth step, the raw material liquid is applied to the entire fin group (20).

[0024] In the ninth aspect, the hydrophilic layer (40) is formed on the entire fin group (20).

[0025] A tenth aspect of the present disclosure is a method for manufacturing the heat exchanger (10) included in the indoor unit (120) of the first aspect described above, comprising: a first step of processing a metal plate material having the hydrophilic layer (40) formed on a surface thereof to form the fins (30); a second step of combining the fin group (20) consisting of the plurality of fins (30) formed in the first step with the heat transfer tubes (50); and a third step of joining the refrigerant pipes (55) to the heat transfer tubes (50) combined with the fin group (20) in the second step, wherein in the third step, the heat transfer tubes (50) and the refrigerant pipes (55) are joined using a joining material that has fluidity at 200°C or lower.

[0026] In the third step of the tenth aspect, the heat transfer tubes (50) and the refrigerant pipes (55) are joined using a joining material that has fluidity at 200°C or lower. Therefore, even when the joining material is heated to allow it to flow into the joint between the heat transfer tubes (50) and the refrigerant pipes (55), the temperature of the assembly (15) is maintained at 200°C or lower. Accordingly, in the third step, the temperature of the fin group (20) is maintained at 200°C or lower even in portions of the fin group (20) located near the joint between the heat transfer tubes (50) and the refrigerant pipes (55). Therefore, the hydrophilic layer (40) formed on the surfaces of the fins (30) does not disappear in the third step. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] [Figure 1] Figure 1 is a piping diagram of a refrigerant circuit showing the configuration of an air conditioner according to Embodiment 1. [Figure 2] Figure 2 is a front view of an indoor unit according to Embodiment 1. [Figure 3] Figure 3 is a cross-sectional view of the indoor unit taken along line III-III in Figure 2. [Figure 4] Figure 4 is a perspective view of an indoor heat exchanger according to Embodiment 1. [Figure 5] Figure 5 is a front view of the indoor heat exchanger according to Embodiment 1. [Figure 6] Figure 6 is a front view of a main heat exchange section that constitutes the indoor heat exchanger. [Figure 7]Figure 7 is a cross-sectional view of the indoor heat exchanger showing the VII-VII section in Figure 6. [Figure 8] Figure 8 is a cross-sectional view of the indoor heat exchanger showing the VIII-VIII section in Figure 7. [Figure 9] Figure 9 is a front view of the heat exchange section showing the state of the heat exchange section in the manufacturing method of the indoor heat exchanger of Embodiment 1. [Figure 10] Figure 10 is a front view of the indoor heat exchanger showing the state of the indoor heat exchanger in the manufacturing method of the indoor heat exchanger according to Embodiment 1. [Figure 11] Figure 11 is a front view of an indoor heat exchanger, a modified example of Embodiment 1. [Figure 12] Figure 12 is a front view of the indoor heat exchanger of Embodiment 2. [Figure 13] Figure 13 is a front view of the heat exchange section showing the state of the heat exchange section in the manufacturing method of the indoor heat exchanger of Embodiment 2. [Figure 14] Figure 14 is a front view of the heat exchange section showing the state of the heat exchange section in the manufacturing method of the indoor heat exchanger of Embodiment 3. [Figure 15] Figure 15 is a cross-sectional view showing a cross-section of an indoor unit of another embodiment, corresponding to Figure 3. [Modes for carrying out the invention]

[0028] Embodiment 1 Embodiment 1 will now be described. This embodiment is an air conditioner (100).

[0029] -Air conditioner- As shown in Figure 1, the air conditioner (100) comprises an outdoor unit (110) and an indoor unit (120). The outdoor unit (110) is installed in an outdoor space. The indoor unit (120) is installed in an indoor space of a building (such as a house).

[0030] The air conditioner (100) is equipped with a refrigerant circuit (130). The refrigerant circuit (130) includes a compressor (131), an outdoor heat exchanger (132), an expansion valve (133), an indoor heat exchanger (10), and a four-way switching valve (134).

[0031] The outdoor unit (110) houses a compressor (131), an outdoor heat exchanger (132), an expansion valve (133), and a four-way switching valve (134). The outdoor unit (110) is also equipped with an outdoor fan (111). The indoor unit (120) houses an indoor heat exchanger (10). The indoor unit (120) is also equipped with an indoor fan (125).

[0032] The refrigerant circuit (130) is constructed by connecting a compressor (131), an outdoor heat exchanger (132), an expansion valve (133), an indoor heat exchanger (10), and a four-way directional control valve (134) with piping. The discharge pipe of the compressor (131) is connected to the first port of the four-way directional control valve (134). The suction pipe of the compressor (131) is connected to the second port of the four-way directional control valve (134). In the refrigerant circuit (130), the outdoor heat exchanger (132), the expansion valve (133), and the indoor heat exchanger (10) are arranged in order from the third port to the fourth port of the four-way directional control valve (134).

[0033] The four-way switching valve (134) switches between a first state, shown by a solid line in Figure 1, and a second state, shown by a dashed line in Figure 1. In the first state, the four-way switching valve (134) communicates with the third port and the second port communicates with the fourth port. In the second state, the four-way switching valve (134) communicates with the fourth port and the second port communicates with the third port.

[0034] -Indoor Unit- As shown in Figures 2 and 3, the indoor unit (120) is wall-mounted. The indoor unit (120) is installed on the wall of the room.

[0035] The indoor unit (120) includes a casing (121). The casing (121) is formed in a horizontally elongated box shape. An intake port (122) is formed at the top of the casing (121). An outlet port (123) is formed at the bottom of the casing (121). The outlet port (123) is a long, narrow opening extending in the reference direction. The reference direction is the left-right direction when the indoor unit (120) is viewed from the front.

[0036] The indoor unit (120) is divided into a first part (120a), a second part (120b), and a third part (120c). The first part (120a) is the part to the right of the air outlet (123) when the indoor unit (120) is viewed from the front. The second part (120b) is the part to the left of the air outlet (123) when the indoor unit (120) is viewed from the front. The third part (120c) is the part between the first part (120a) and the second part (120b) when the indoor unit (120) is viewed from the front. The third part (120c) includes the entire air outlet (123).

[0037] A flap (124) is provided at the outlet (123) of the casing (121). The flap (124) is formed in the shape of an elongated plate. The flap (124) is a component for adjusting the direction of the air blown out from the outlet (123). The flap (124) can be displaced between a closed position that covers the outlet (123) and an open position that opens the outlet (123).

[0038] As shown in Figure 3, the casing (121) houses an indoor heat exchanger (10), an indoor fan (125), and an air filter (126). The indoor fan (125) is a so-called cross-flow fan. The indoor heat exchanger (10) is installed from the front to the top of the indoor fan (125). The air filter (126) is installed from the front to the top of the indoor heat exchanger (10).

[0039] As shown in Figures 3 and 4, the indoor heat exchanger (10) comprises a first heat exchange section (11), a second heat exchange section (12), and a third heat exchange section (13). The first heat exchange section (11) is located on the upper side towards the front of the indoor fan (125). The second heat exchange section (12) is located on the lower side towards the front of the indoor fan (125). The third heat exchange section (13) is located on the upper side towards the rear of the indoor fan (125).

[0040] Each of the first heat exchange section (11), the second heat exchange section (12), and the third heat exchange section (13) comprises a main heat exchange section (11a, 12a, 13a) and a secondary heat exchange section (11b, 12b, 13b). In each heat exchange section (11, 12, 13), the main heat exchange section (11a, 12a, 13a) is located downstream of the airflow (in other words, on the side of the indoor fan (125)), and the secondary heat exchange section (11b, 12b, 13b) is located upstream of the airflow (in other words, on the side of the air filter (126)). The secondary heat exchange section (11b, 12b, 13b) is an auxiliary heat exchange section located upstream of the main heat exchange section (11a, 12a, 13a).

[0041] As shown in Figure 3, in the indoor heat exchanger (10) installed in the indoor unit (120), the long sides (31,32) of the fins (30) of the first heat exchange section (11), the long sides (31,32) of the fins (30) of the second heat exchange section (12), and the long sides (31,32) of the fins (30) of the third heat exchange section (13) are each inclined with respect to the vertical. The inclination angle α, which is the angle of the long sides (31,32) of the fins (30) of the first heat exchange section (11) with respect to the vertical, and the inclination angle γ, which is the angle of the long sides (31,32) of the fins (30) of the third heat exchange section (13) with respect to the vertical, are both between 30° and 50° (30°≦α≦50°, 30°≦γ≦50°). On the other hand, the inclination angle β, which is the angle of the long sides (31,32) of the fins (30) of the second heat exchange section (12) with respect to the vertical, may be 50° or more.

[0042] -Air conditioner operation- The air conditioner (100) performs both cooling and heating operations.

[0043] <Cooling operation> The cooling operation is an operation in which the indoor heat exchanger (10) of the indoor unit (120) cools the air. This cooling operation includes both cooling operation and dehumidification operation.

[0044] During cooling operation, the four-way switching valve (134) is set to the first state and the compressor (131) operates. In the refrigerant circuit (130), the refrigerant circulates and the refrigeration cycle is performed. In the refrigerant circuit (130), the outdoor heat exchanger (132) functions as a heat radiator and the indoor heat exchanger (10) functions as an evaporator. The indoor unit (120) cools the air drawn in from the indoor space by the indoor heat exchanger (10) and blows the cooled air back into the indoor space.

[0045] <Heating operation> The heating operation is an operation in which the indoor heat exchanger (10) of the indoor unit (120) heats the air. This heating operation is a heating operation.

[0046] During heating operation, the four-way switching valve (134) is set to the second state and the compressor (131) operates. In the refrigerant circuit (130), the refrigerant circulates and the refrigeration cycle is performed. In the refrigerant circuit (130), the indoor heat exchanger (10) functions as a heat radiator and the outdoor heat exchanger (132) functions as an evaporator. The indoor unit (120) heats the air drawn in from the indoor space using the indoor heat exchanger (10) and blows the heated air back into the indoor space.

[0047] -Indoor heat exchanger- The indoor heat exchanger (10) is a cross-fin type heat exchanger. The indoor heat exchanger (10) is installed across the first part (120a), the third part (120c), and the second part (120b) of the indoor unit (120) (see Figure 2).

[0048] As described above, the indoor heat exchanger (10) comprises a first heat exchange section (11), a second heat exchange section (12), and a third heat exchange section (13). Each of the main heat exchange sections (11a, 12a, 13a) and secondary heat exchange sections (11b, 12b, 13b) of each heat exchange section (11, 12, 13) is equipped with multiple fins (30) and heat transfer tubes (50), and the air flowing between the fins (30) is used to exchange heat with the refrigerant flowing through the heat transfer tubes (50).

[0049] In each of the main heat exchange sections (11a, 12a, 13a) and secondary heat exchange sections (11b, 12b, 13b) of each heat exchange section (11, 12, 13), a plurality of fins (30) are arranged in a line in the reference direction (left-right direction as shown in Figure 2) to form a fin group (20). The fin group (20) of each heat exchange section (11, 12, 13) is provided across the first part (120a), the third part (120c), and the second part (120b) of the indoor unit (120) (see Figure 2).

[0050] As shown in Figure 5, the fin group (20) of each heat exchange section (11, 12, 13) is divided into a right portion (21), a left portion (22), and an intermediate portion (23). The right portion (21) is the part of the fin group (20) located in the first portion (120a) of the indoor unit (120). The left portion (22) is the part of the fin group (20) located in the second portion (120b) of the indoor unit (120). The intermediate portion (23) is the part of the fin group (20) located in the third portion (120c) of the indoor unit (120).

[0051] The structure of the indoor heat exchanger (10) will be explained using the main heat exchange section (11a) of the first heat exchange section (11) as an example. Note that the structure of the main heat exchange section (12a) of the second heat exchange section (12) and the structure of the main heat exchange section (13a) of the third heat exchange section (13) are substantially the same as the structure of the main heat exchange section (11a) of the first heat exchange section (11). Furthermore, the structure of the secondary heat exchange sections (11b, 12b, 13b) of each heat exchange section (11, 12, 13) is substantially the same as the structure of the main heat exchange section (11a) of the first heat exchange section (11), except that multiple heat transfer tubes (50) are arranged in a single line.

[0052] As shown in Figure 6, the main heat exchange section (11a) of the first heat exchange section (11) is equipped with multiple fins (30), multiple heat transfer tubes (50), and multiple U-shaped tubes (56).

[0053] <fin> The fins (30) are rectangular plate-shaped members. The material of the fins (30) is aluminum or an aluminum alloy. The fins (30) are formed by press-forming a metal plate. Multiple fins (30) are arranged in a row in the reference direction (left-right direction in Figure 2). As described above, multiple fins (30) arranged in a row from left to right constitute a fin group (20).

[0054] As shown in Figure 7, the fin (30) has a pair of long sides. The windward long side of the fin (30) is the leading edge (31). The leeward long side of the fin (30) is the trailing edge (32).

[0055] As shown in Figures 7 and 8, the fin (30) comprises a main body (35) and a plurality of collar parts (36). The collar parts (36) are cylindrical portions that protrude from the main body (35). The plurality of collar parts (36) are arranged in two rows along the long sides (31, 32) of the fin (30).

[0056] Multiple cut-out sections (37) are formed on the main body (35). The cut-out sections (37) are raised portions in the direction of protrusion of the collar section (36). The cut-out sections (37) have cut edges (37a) that extend along the long sides (31, 32) of the fin (30). The cut-out sections (37) are formed on the fin (30) to promote heat transfer between the fin (30) and the air.

[0057] As shown in Figure 8, in the fin group (20), the tip of the collar portion (36) of the fin (30) touches the adjacent fin (30), thereby maintaining a constant arrangement pitch of the body portions (35) of adjacent fins (30). The arrangement pitch of the body portions (35) of the fins (30) is the arrangement pitch FP of the fins (30). The arrangement pitch FP of the fins (30) in the fin group (20) is 1.3 mm. It is desirable that the arrangement pitch FP of the fins (30) in the fin group (20) be 1.5 mm or less (FP ≤ 1.5).

[0058] A hydrophilic layer (40) is formed on the surface of the fins (30). In the indoor heat exchanger (10) of this embodiment, a hydrophilic layer (40) is formed on the surface of all the fins (30) that make up the fin group (20). Therefore, in the indoor heat exchanger (10) of this embodiment, a hydrophilic layer (40) is formed over the entire fin group (20). The hydrophilic layer (40) is a film made of a hydrophilic material. Examples of hydrophilic materials that make up the hydrophilic layer (40) include polyvinyl resin, polyacrylic resin, or mixtures thereof.

[0059] <Heat transfer tube> As shown in Figure 6, the heat transfer tube (50) is a circular tube formed in a hairpin shape. The material of the heat transfer tube (50) is aluminum or an aluminum alloy. The material of the heat transfer tube (50) may also be copper or a copper alloy. The heat transfer tube (50) comprises a pair of straight pipe sections (51) and a curved pipe section (52) that is continuous with one end (the left end in Figure 6) of each straight pipe section (51).

[0060] The straight section (51) of the heat transfer tube (50) penetrates the fins (30) which are arranged in the left-right direction. As shown in Figure 8, the straight section (51) of the heat transfer tube (50) is inserted through the collar section (36) of each fin (30) that makes up the fin group (20).

[0061] <U-shaped tube> The U-shaped tube (56) is a circular tube formed in a U-shape. The U-shaped tube (56) is joined to the other end (right end in Figure 5) of the straight section (51) of the heat transfer tube (50). The U-shaped tube (56) connects adjacent heat transfer tubes (50).

[0062] The U-shaped pipe (56) is a type of refrigerant pipe (55) connected to the heat transfer tube (50). In addition to the U-shaped pipe (56), the indoor heat exchanger (10) includes refrigerant pipes (55) that connect the heat exchange sections (11, 12, 13) to each other, and refrigerant pipes (55) that connect the indoor heat exchanger (10) to the piping outside the indoor unit (120).

[0063] -Manufacturing method for indoor heat exchangers- A method for manufacturing an indoor heat exchanger will be described with reference to Figures 9 and 10. This manufacturing method comprises a first step, a second step, a third step, a fourth step, and a fifth step.

[0064] <1st process> The first step is to process a metal sheet to form fins (30). In the first step, fins (30) are formed by press working on a metal sheet that does not have a hydrophilic layer formed on its surface.

[0065] <2nd process> The second step is to combine the fins (30) formed in the first step with the heat transfer tubes (50). The second step is performed individually for each of the main heat exchange sections (11a, 12a, 13a) and secondary heat exchange sections (11b, 12b, 13b) of each heat exchange section (11, 12, 13).

[0066] First, a fin group (20) is formed by arranging multiple fins (30) in a line (see Figure 9(a)). In the fin group (20), the corresponding collar portions (36) of each fin (30) are arranged in a substantially straight line.

[0067] Next, the heat transfer tubes (50) are inserted through the fin group (20) (see Figure 9(b)). Specifically, the straight section (51) of the hairpin-shaped heat transfer tube (50) is inserted through the collar section (36) of each fin (30) that makes up the fin group (20).

[0068] Next, the heat transfer tube (50) is expanded. The expansion process involves increasing the outer diameter of the straight section (51) of the heat transfer tube (50). In the expansion process, an expansion head with an outer diameter larger than the inner diameter of the straight section (51) is used. In the expansion process, the outer diameter of the straight section (51) is increased by inserting the expansion head into the straight section (51). As a result, the outer surface of the straight section (51) comes into close contact with the inner surface of the collar section (36) of the fin (30), and the heat transfer tube (50) is fixed to the fin group (20).

[0069] <3rd process> The third step is to join the refrigerant pipe (55) to the heat transfer tube (50) which was combined with the fin group (20) in the second step. In the third step, the refrigerant pipe (55) is joined to the heat transfer tube (50) by brazing.

[0070] First, a U-shaped pipe (56), which is a type of refrigerant pipe (55), is joined to the open end (right end in Figure 9) of the straight section (51) of the heat transfer tube (50) (Figure 9(c)). This operation is performed individually for each of the main heat exchange sections (11a, 12a, 13a) and secondary heat exchange sections (11b, 12b, 13b) of each heat exchange section (11, 12, 13).

[0071] The U-shaped tube (56) is joined to the straight tube section (51) by brazing. Brazing is a joining method that uses a metal brazing material as the joining material. Generally, brazing material melts when heated to 450°C or higher. In the process of joining the U-shaped tube (56) to the straight tube section (51), the joint between the U-shaped tube (56) and the straight tube section (51) is heated to 450°C or higher with a burner or the like, and the molten brazing material is allowed to enter the gap between the U-shaped tube (56) and the straight tube section (51). Once the brazing material that has entered the gap between the U-shaped tube (56) and the straight tube section (51) solidifies, the U-shaped tube (56) is fixed to the straight tube section (51).

[0072] Next, an assembly (15) is formed by combining the main heat exchange sections (11a, 12a, 13a) and secondary heat exchange sections (11b, 12b, 13b) of each heat exchange section (11, 12, 13). In the assembly (15), the main heat exchange sections (11a, 12a, 13a) and secondary heat exchange sections (11b, 12b, 13b) of each heat exchange section (11, 12, 13) are relatively fixed.

[0073] The refrigerant pipes (55), other than the U-shaped pipes (56), are joined to the straight pipe section (51) of the heat transfer tube (50) provided in the assembly (15) by brazing. In this process, similar to when the U-shaped pipe (56) is joined to the straight pipe section (51), the joint between the straight pipe section (51) and the refrigerant pipe (55) is heated to 450°C or higher using a burner or the like.

[0074] <4th process> The fourth step is to apply the raw material liquid (45) to the fin group (20) of the assembly (15). The raw material liquid (45) is a mixture of a hydrophilic material that constitutes the hydrophilic layer (40) and a solvent such as water.

[0075] In the fourth step, the assembly (15) is immersed in the raw material liquid (45) stored in the liquid tank (see Figure 10(d)). When the assembly (15) is removed from the raw material liquid (45), the raw material liquid (45) is applied to the entire fin group (20). Thus, in the fourth step of this embodiment, the raw material liquid (45) is applied to the entire fin group (20), including the intermediate portion (23).

[0076] <5th process> The fifth step involves drying the raw material liquid (45) applied to the fin group (20) of the assembly (15) to form a hydrophilic layer (40).

[0077] In the fifth step, the assembly (15) to which the raw material liquid (45) was applied in the fourth step is heated to, for example, about 40°C to evaporate the solvent contained in the raw material liquid (45). Once the solvent has evaporated, a hydrophilic layer (40) is formed by the hydrophilic material remaining on the surface of the fin group (20) (see Figure 10(e)). In the fifth step of this embodiment, a hydrophilic layer (40) is formed over the entire fin group (20), including the intermediate portion (23).

[0078] -Features of Embodiment 1 (1)- The middle section (23) of the fin group (20) of the indoor heat exchanger (10) is located in the third section (120c) of the indoor unit (120). The third section (120c) of the indoor unit (120) includes the entire outlet (123). Therefore, if condensate is scattered from the middle section (23) of the fin group (20), there is a high probability that the scattered condensate will be blown out of the outlet (123) along with the air.

[0079] On the other hand, in the indoor heat exchanger (10) of this embodiment, a hydrophilic layer (40) is formed on the entire surface of the fin group (20), including the intermediate portion (23). When a hydrophilic layer (40) is present on the surface of the fin group (20), the condensed water generated on the surface of the fin group (20) is less likely to peel off from the surface of the fin group (20). Therefore, according to this embodiment, the scattering of condensed water from the intermediate portion (23) of the fin group (20) is suppressed, and the "water splashing phenomenon" in which condensed water is scattered from the indoor unit (120) is suppressed.

[0080] -Features of Embodiment 1 (2)- In the indoor heat exchanger (10) of this embodiment, the heat transfer tubes (50) and refrigerant tubes (55) are made of aluminum or an aluminum alloy. When joining aluminum or aluminum alloy heat transfer tubes (50) and refrigerant tubes (55) by brazing, the heating time at the joint tends to be longer compared to when joining copper or copper alloy heat transfer tubes and refrigerant tubes by brazing.

[0081] If the heating time at the joint is prolonged, the temperature of the part of the fin group (20) located near the joint between the heat transfer tube (50) and the refrigerant tube (55) may become relatively high (for example, 300°C or higher). If a hydrophilic layer is formed on the fin group before the brazing work, the rise in temperature during the brazing work may cause a portion of the hydrophilic layer to carbonize, and the hydrophilicity of the carbonized portion will be lost.

[0082] On the other hand, in the manufacturing method of the indoor heat exchanger (10) of this embodiment, the fourth and fifth steps for forming the hydrophilic layer (40) are performed after the third step of brazing. Therefore, in the indoor heat exchanger (10) of this embodiment, a hydrophilic layer (40) can be formed over the entire fin group (20) while using heat transfer tubes (50) and refrigerant tubes (55) made of aluminum or aluminum alloy.

[0083] -Features of Embodiment 1 (3)- In the indoor heat exchanger (10) of this embodiment, the inclination angle α of the first heat exchange section (11), the inclination angle β of the second heat exchange section (12), and the inclination angle γ of the third heat exchange section (13) are all between 30° and 45°. Therefore, the condensed water generated on the surface of the fins (30) of each heat exchange section (11, 12, 13) does not fall from the trailing edge (32) of the fins (30), but flows down along the surface of the fins (30). As a result, the scattering of condensed water from the fin group (20) is suppressed, and the "water splashing phenomenon" in which condensed water is scattered from the indoor unit (120) is suppressed.

[0084] -Variation 1 of Embodiment 1- As shown in Figure 11, in the fin group (20) of the indoor heat exchanger (10) of this embodiment, a hydrophilic layer (40) may be formed only on the intermediate portion (23). In the fin group (20) of this modified example, the entire right portion (21) and the left portion (22) are non-hydrophilic regions (25) where no hydrophilic layer (40) exists on the surface. In addition, in the fin group (20) of this modified example, a portion of the right portion (21) and the left portion (22) may be non-hydrophilic regions.

[0085] In the fourth step of the manufacturing method for the indoor heat exchanger (10) of this modified example, the raw material liquid is applied only to the intermediate portion (23) of the fin group (20) of the assembly (15). In this fourth step, the raw material liquid is applied to the intermediate portion (23) of the fin group (20) by spraying it using a spray nozzle or the like.

[0086] -Modification 2 of Embodiment 1- In the indoor heat exchanger (10) of this embodiment, the fin group (20) and the heat transfer tubes (50) may be joined by brazing.

[0087] In the second step of the manufacturing method for the indoor heat exchanger (10) of this modified example, furnace brazing is performed instead of tube expansion. Specifically, in this second step, the fin group (20) and the heat transfer tube (50) are assembled, and brazing material is placed between the fin group (20) and the heat transfer tube (50). Subsequently, the assembled fin group (20) and heat transfer tube (50) are heated in a heating furnace, and the brazing material melts, joining the fin group (20) and the heat transfer tube (50).

[0088] In addition, in the second step of this modified example, the brazing operation in the furnace may be performed along with the brazing of the fin group (20) and the heat transfer tube (50), as well as the brazing of the heat transfer tube (50) and the refrigerant tube (55). In this case, the brazing operation in the second step and the third step are performed simultaneously and in parallel.

[0089] Embodiment 2 Embodiment 2 will now be described.

[0090] In the air conditioner (100) of this embodiment, the configuration of the indoor heat exchanger (10) of the indoor unit (120) differs from that of the indoor heat exchanger (10) of Embodiment 1. Furthermore, the manufacturing method of the indoor heat exchanger (10) of this embodiment differs from that of the indoor heat exchanger (10) of Embodiment 1.

[0091] -Indoor heat exchanger configuration- As shown in Figure 12, in the fin group (20) of the indoor heat exchanger (10) of this embodiment, a hydrophilic layer (40) is formed in the entirety of the intermediate portion (23) and the left portion (22), and in a portion of the right portion (21). In the right portion (21), a hydrophilic layer (40) is formed in the region along the boundary with the intermediate portion (23). The remaining region of the right portion (21) is a non-hydrophilic region (25) where the hydrophilic layer (40) is not formed. In all other respects, the configuration of the indoor heat exchanger (10) of this embodiment is the same as the configuration of the indoor heat exchanger (10) of Embodiment 1.

[0092] -Manufacturing method for indoor heat exchangers- The manufacturing method for the indoor heat exchanger (10) of this embodiment will be described with reference to Figure 13. This manufacturing method comprises a first step, a second step, and a third step.

[0093] <1st process> The first step is to process a metal sheet to form fins (30). In the first step, fins (30) are formed by press working on a metal sheet that has a hydrophilic layer (40) already formed on its surface. The first step of this embodiment differs from the first step of Embodiment 1 in that the hydrophilic layer (40) is formed on the metal sheet before press working.

[0094] <2nd process> The second step is to combine the fins (30) formed in the first step with the heat transfer tubes (50). The second step is performed individually for each of the main heat exchange sections (11a, 12a, 13a) and secondary heat exchange sections (11b, 12b, 13b) of each heat exchange section (11, 12, 13).

[0095] The second step of this embodiment is the same as the second step of Embodiment 1. However, in the first step of this embodiment, fins (30) are formed by processing a metal plate material that has a hydrophilic layer (40) pre-formed on its surface. Therefore, in the fin group (20) formed in the second step, the hydrophilic layer (40) is formed over its entire surface (see Figure 13(a)). In the second step, the straight pipe section (51) of the heat transfer tube (50) is inserted through this fin group (20), and the heat transfer tube (50) is fixed to the fin group (20) by an expansion operation (see Figure 13(b)).

[0096] <3rd process> The third step is to join the refrigerant pipe (55) to the heat transfer tube (50) which was combined with the fin group (20) in the second step. In the third step, the refrigerant pipe (55) is joined to the heat transfer tube (50) by brazing. The third step in this embodiment is the same as the third step in Embodiment 1.

[0097] In the third step, the joint between the straight pipe section (51) and the refrigerant pipe (55) is heated to over 450°C by a burner or the like. At this time, the region of the fin group (20) that is close to the joint between the straight pipe section (51) and the refrigerant pipe (55) also becomes relatively hot (for example, over 300°C). In the region of the fin group (20) that has become relatively hot, the hydrophilic layer (40) formed on the fin group (20) carbonizes and disappears. As a result, the region of the fin group (20) that is close to the joint between the straight pipe section (51) and the refrigerant pipe (55) becomes a non-hydrophilic region (25) where the hydrophilic layer (40) does not exist on the surface (see Figure 13(c)).

[0098] In the third step of this embodiment, similar to the third step of Embodiment 1, an assembly (15) is formed by combining the main heat exchange sections (11a, 12a, 13a) and secondary heat exchange sections (11b, 12b, 13b) of each heat exchange section (11, 12, 13). In the assembly (15), the main heat exchange sections (11a, 12a, 13a) and secondary heat exchange sections (11b, 12b, 13b) of each heat exchange section (11, 12, 13) are relatively fixed.

[0099] The refrigerant pipes (55), other than the U-shaped pipes (56), are joined to the straight pipe sections (51) of the heat transfer tubes (50) provided in the assembly (15) by brazing. In this process, similar to when the U-shaped pipes (56) are joined to the straight pipe sections (51), the joint between the straight pipe sections (51) and the refrigerant pipes (55) is heated to over 450°C by a burner or the like. During this process, the hydrophilic layer (40) formed on the fin group (20) carbonizes and disappears.

[0100] -Features of Embodiment 2- In the indoor heat exchanger (10) of this embodiment, a portion of the hydrophilic layer (40) formed on the fin group (20) disappears in the third step of its manufacturing method. However, in the fin group (20) of the indoor heat exchanger (10) of this embodiment, the entire non-hydrophilic region (25) is included in the right portion (21) of the fin group (20), and the hydrophilic layer (40) is present throughout the intermediate portion (23). Therefore, according to this embodiment, the scattering of condensed water from the intermediate portion (23) of the fin group (20) is suppressed, and the "water splashing phenomenon" in which condensed water is scattered from the indoor unit (120) is suppressed.

[0101] Embodiment 3 Embodiment 3 will now be described.

[0102] In the air conditioner (100) of this embodiment, the configuration of the indoor heat exchanger (10) of the indoor unit (120) is the same as that of the indoor heat exchanger (10) of Embodiment 1. Therefore, in the indoor heat exchanger (10) of this embodiment, a hydrophilic layer (40) is formed over the entire fin group (20), similar to the indoor heat exchanger (10) of Embodiment 1.

[0103] On the other hand, the manufacturing method of the indoor heat exchanger (10) in this embodiment differs from the manufacturing method of the indoor heat exchanger (10) in Embodiment 2. In the manufacturing method of the indoor heat exchanger (10) in this embodiment, the first and second steps are the same as those of the manufacturing method of the indoor heat exchanger (10) in Embodiment 2, but the third step differs from that of the manufacturing method of the indoor heat exchanger (10) in Embodiment 2.

[0104] In the third step of this embodiment, the straight section (51) of the heat transfer tube (50) and the refrigerant tube (55) are joined using an adhesive. In the third step, for example, the adhesive is applied to the end of the refrigerant tube (55), and the adhesive-coated end is inserted into the open end of the straight section (51). The refrigerant tube (55) is then joined to the straight section (51) as the adhesive hardens.

[0105] Adhesives are an example of bonding materials that are fluid at temperatures below 200°C. For example, adhesives primarily composed of epoxy resin can be used.

[0106] Other embodiments The following modifications may be applied to the indoor heat exchanger (10) of Embodiments 1 to 3.

[0107] As shown in Figure 15, in each heat exchange section (11, 12, 13) of the indoor heat exchanger (10) of Embodiments 1 to 3, a hydrophilic layer (40) is formed on the fin group (20) of the main heat exchange section (11a, 12a, 13a), while the entire fin group (20) of the secondary heat exchange section (11b, 12b, 13b) may be a non-hydrophilic region (25) where the hydrophilic layer (40) does not exist. In this case, condensed water may be scattered from the secondary heat exchange section (11b, 12b, 13b). The condensed water scattered from the secondary heat exchange section (11b, 12b, 13b) adheres to the fin group (20) of the main heat exchange section (11a, 12a, 13a) located downstream of the secondary heat exchange section (11b, 12b, 13b). Therefore, the condensed water scattered from the auxiliary heat exchange section (11b, 12b, 13b) does not reach the outlet (123) of the indoor unit (120), and consequently is not blown into the room along with the air from the outlet (123).

[0108] The heat transfer tubes (50) in the indoor heat exchanger (10) of Embodiments 1 to 3 are not limited to heat transfer tubes with a circular cross-section. The heat transfer tubes (50) constituting the indoor heat exchanger (10) may be so-called flattened tubes. A flattened tube is a tube with a flattened cross-sectional shape in which the width is greater than the thickness.

[0109] While embodiments and modifications have been described above, it will be understood that various changes in form and details are possible without departing from the spirit and scope of the claims. Furthermore, elements of the embodiments, modifications, and other embodiments described above may be combined or substituted as appropriate. In addition, the designations "first," "second," "third," etc. in the specification and claims are used to distinguish the phrases to which these designations are given, and do not limit the number or order of such phrases. [Industrial applicability]

[0110] As described above, this disclosure is useful for manufacturing indoor units and heat exchangers for air conditioners. [Explanation of Symbols]

[0111] 10 Indoor heat exchanger (heat exchanger) 11b 1st auxiliary heat exchange section (auxiliary heat exchange section) 12b Second auxiliary heat exchange section (auxiliary heat exchange section) 13b 3rd auxiliary heat exchange section (auxiliary heat exchange section) 20 fin group 21 Right side part 22 Left side part 23 Middle part 25 Non-hydrophilic region 30 fins 31 Front edge (long side) 32. Trailing edge (long side) 40 Hydrophilic layer 50 heat transfer tubes 55 Refrigerant pipes 100 Air conditioners 120 Indoor Unit 120a Part 1 120b 2nd part 120c 3rd part 121 Casing 123 Air outlet 125 Indoor Fan (Fan)

Claims

1. An indoor unit (120) of an air conditioner comprising a heat exchanger (10) for exchanging heat between air and a refrigerant, a fan (125), and a casing (121) housing the heat exchanger (10) and the fan (125), The left-right direction when viewing the above indoor unit (120) from the front is the reference direction. The casing (121) has an outlet (123) extending in the reference direction. The heat exchanger (10) comprises a fin group (20) consisting of a plurality of fins (30) arranged in the reference direction, a heat transfer tube (50), and a refrigerant pipe (55) connected to the heat transfer tube (50). Of the indoor unit (120) described above, the portion to the right of the air outlet (123) when the indoor unit (120) is viewed from the front is the first portion (120a). Of the indoor unit (120) described above, the part to the left of the air outlet (123) when the indoor unit (120) is viewed from the front is the second part (120b). Of the indoor unit (120) described above, the third part (120c) is located between the first part (120a) and the second part (120b) and includes the entire air outlet (123). The above-mentioned fin group (20) is provided across the first portion (120a), the third portion (120c), and the second portion (120b) of the indoor unit (120). Of the above fin group (20), the part located in the third part (120c) of the above indoor unit (120) is the intermediate part (23). A hydrophilic layer (40) made of a hydrophilic material is formed on the entire surface of the intermediate portion (23) described above. Indoor unit of an air conditioner.

2. The hydrophilic layer (40) is formed on the entire surface of the fin group (20). An indoor unit for an air conditioner according to claim 1.

3. Of the fin group (20) described above, the portion located in the first part (120a) of the indoor unit (120) is the right-side portion (21). Of the fin group (20) described above, the part located in the second part (120b) of the indoor unit (120) described above is the left part (22). A part or all of the right-hand portion (21) and a part or all of the left-hand portion (22) are non-hydrophilic regions (25) on which the hydrophilic layer (40) does not exist on the surface. An indoor unit for an air conditioner according to claim 1.

4. The material of the heat transfer tube (50) and the refrigerant tube (55) is aluminum or an aluminum alloy. An indoor unit for an air conditioner according to any one of claims 1 to 3.

5. Each of the multiple fins (30) constituting the fin group (20) is formed in a plate shape having a pair of parallel long sides (31, 32), The inclination angle of the long sides (31, 32) of the fin (30) with respect to the vertical is 30° or more and 50° or less. An indoor unit for an air conditioner according to any one of claims 1 to 3.

6. The arrangement pitch of the multiple fins (30) in the fin group (20) is 1.5 mm or less. An indoor unit for an air conditioner according to any one of claims 1 to 3.

7. The above heat exchanger (10) is equipped with auxiliary heat exchange sections (11b, 12b, 13b) that exchange heat between air and a refrigerant. The above auxiliary heat exchange sections (11b, 12b, 13b) are positioned upstream of the fin group (20) in the direction of airflow passing through the heat exchanger (10). The entirety of the above auxiliary heat exchange section (11b, 12b, 13b) is a non-hydrophilic region (25) where the above hydrophilic layer (40) does not exist on the surface. An indoor unit for an air conditioner according to any one of claims 1 to 3.

8. A method for manufacturing the heat exchanger (10) provided in the indoor unit (120) described in claim 1, A first step involves processing a metal sheet to form the fins (30), A second step involves combining the fin group (20), which consists of the multiple fins (30) formed in the first step, with the heat transfer tube (50), A third step involves joining the refrigerant pipe (55) to the heat transfer tube (50) which is combined with the fin group (20) in the second step above by brazing, A fourth step involves applying a raw material solution containing a hydrophilic material to the entire intermediate portion (23) of the fin group (20) that has undergone the third step, The fourth step involves drying the raw material liquid applied to the fin group (20) in the fourth step, thereby forming the hydrophilic layer (40) on the surface of the intermediate portion (23) of the fin group (20). A method for manufacturing a heat exchanger.

9. In the fourth step described above, the raw material liquid is applied to the entire fin group (20). A method for manufacturing a heat exchanger according to claim 8.

10. A method for manufacturing the heat exchanger (10) provided in the indoor unit (120) described in claim 1, A first step is to process a metal plate material having the hydrophilic layer (40) formed on its surface to form the fin (30), A second step involves combining the fin group (20), which consists of the multiple fins (30) formed in the first step, with the heat transfer tube (50), The process further includes a third step of joining the refrigerant pipe (55) to the heat transfer tube (50) which is combined with the fin group (20) in the second step described above, In the third step described above, the heat transfer tube (50) and the refrigerant tube (55) are joined using a joining material that is fluid at 200°C or below. A method for manufacturing a heat exchanger.

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