Air conditioner

Abstract

To suppress generation of refrigerant noise in an indoor unit.SOLUTION: An air conditioner comprises a downstream connection pipe located at a downstream side of a flow of refrigerant R with respect to a heat transfer pipe 22 during cooling operation. The downstream connection pipe comprises: gas piping 30a (first piping) having a first main pipe part 30a1 with an inner diameter D11, and a first small-diameter part 30a2 with an inner diameter D12, at least a part of which is located inside the heat transfer pipe 22, the first piping being formed of an aluminum alloy; and a gas piping 30b (a second pipe) having a second main pipe part 30b1 with an inner diameter D21, and a second small-diameter part 30b2 with an inner diameter D22, at least a part of which is located inside the gas piping 30a (the first piping), the second pipe is formed of a copper alloy. The inner diameter D12 is equal to or smaller than the inner diameter D11, the inner diameter D22 is smaller than the inner diameter D21, and a ratio of the inner diameter D11 to the inner diameter D12 is smaller than a ratio of the inner diameter D21 to the inner diameter D22.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an air conditioner. [Background technology]

[0002] Recently, air conditioners have become known that use aluminum pipes in their outdoor heat exchangers (see, for example, Patent Document 1). According to this air conditioner, the manufacturing cost of the air conditioner can be reduced by using aluminum pipes, which are cheaper than copper pipes, in the outdoor unit, where copper pipes have mainly been used in the past. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-013765 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, it is conceivable that the manufacturing costs of air conditioners can be further reduced by using aluminum pipes in the indoor units as well. However, it was discovered that using aluminum pipes in the indoor unit creates a new problem: the refrigerant noise generated by the flowing refrigerant increases. This type of air conditioner may disrupt the quietness of the room.

[0005] An object of the present invention is to provide an air conditioner that can suppress the generation of refrigerant noise in the indoor unit. [Means for solving the problem]

[0006] The air conditioner of the present invention comprises a heat transfer tube made of aluminum or an aluminum alloy, which constitutes at least a part of a refrigerant flow path of an indoor heat exchanger, and a downstream connecting pipe located downstream of the heat transfer tube in the refrigerant flow direction during cooling operation, the downstream connecting pipe having an inner diameter D 11 and a first main pipe portion at least partially located inside the heat transfer tube and having an inner diameter D 12 a first pipe having a first small diameter portion formed of aluminum or an aluminum alloy and an inner diameter D 21 a second main pipe portion at least partially located inside the first pipe and having an inner diameter D 22 and a second pipe formed of copper or a copper alloy, the second pipe having an inner diameter D 12 is the inner diameter D 11 is less than or equal to the inner diameter D 22 is the inner diameter D 21 Smaller and inner diameter D 11 / Inner diameter D 12 The value of the inner diameter D 21 / Inner diameter D 22 is smaller than the value of

[0007] The air conditioner of the present invention also includes a heat transfer tube that constitutes at least a part of a refrigerant flow path of an indoor heat exchanger and is made of aluminum or an aluminum alloy, and an upstream connecting pipe that is located upstream of the refrigerant flow relative to the heat transfer tube during cooling operation, and the upstream connecting pipe has an inner diameter D 31 a third main pipe portion at least partially located inside the heat transfer tube and having an inner diameter D 32 a third pipe made of aluminum or an aluminum alloy and having an inner diameter D 41 a fourth main pipe section at least partially located inside the third pipe and having an inner diameter D 42 and a fourth pipe formed of copper or a copper alloy, and having an inner diameter D 32 is the inner diameter D 31 is less than or equal to the inner diameter D 42 is the inner diameter D 41 Smaller and inner diameter D 31 / Inner diameter D 32 The value of the inner diameter D 41 / Inner diameter D42 is smaller than the value of [Effects of the Invention]

[0008] According to the present invention, it is possible to suppress the generation of refrigerant noise in the indoor unit. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a configuration explanatory diagram of an air conditioner according to an embodiment of the present invention; [Figure 2] 4 is a partially enlarged cross-sectional view schematically illustrating a connection between an indoor heat exchanger in an indoor unit of an air conditioner and a downstream connecting pipe connected to the indoor heat exchanger on the downstream side of the refrigerant. FIG. [Figure 3] 4 is a partially enlarged cross-sectional view schematically illustrating a connection between an indoor heat exchanger in an indoor unit of an air conditioner and an upstream connecting pipe connected to the indoor heat exchanger on the upstream side of the refrigerant. FIG. [Figure 4] FIG. 10 is a partially enlarged cross-sectional view schematically showing a connecting pipe in an air conditioner according to another embodiment of the present invention. [Figure 5] 3 is a partially enlarged cross-sectional view schematically showing a modified example of the downstream connecting pipe shown in FIG. 2. FIG. [Figure 6] 4 is a partially enlarged cross-sectional view schematically showing a modified example of the upstream connecting pipe shown in FIG. 3. FIG. [Figure 7] 10 is a partially enlarged cross-sectional view schematically showing another embodiment of the connection between the heat transfer pipe of the indoor heat exchanger and the connecting pipe. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, a mode (embodiment) for carrying out an air conditioner of the present invention will be described in detail with reference to the drawings as appropriate. First, the overall configuration of the air conditioner will be described, and then the piping in the indoor unit will be described in more detail.

[0011] <Air conditioner> FIG. 1 is a configuration diagram of an air conditioner 100 according to this embodiment. In FIG. 1, the flow of refrigerant in the heating cycle is indicated by solid arrows, and the flow of refrigerant in the cooling cycle is indicated by dashed arrows. As shown in FIG. 1, the air conditioner 100 includes an outdoor unit 101 installed outdoors and an indoor unit 102 installed indoors.

[0012] During cooling operation, the air conditioner 100 takes in liquid refrigerant (including gas-liquid two-phase refrigerant) from the outdoor unit 101 via the liquid piping 20, which has an expansion valve 6 midway along its length, to flow through heat transfer pipes 22 (see FIG. 2 ) of the indoor heat exchanger 4 in the indoor unit 102. At this time, the indoor heat exchanger 4 functions as an evaporator to cool the surrounding air. The gas refrigerant vaporized in the indoor heat exchanger 4 is then sent to the outdoor unit 101 via the gas piping 30.

[0013] The gas refrigerant sent to the outdoor unit 101 becomes liquid refrigerant (including gas-liquid two-phase refrigerant) after passing through the compressor 7 of the outdoor unit 101 and the outdoor heat exchanger 3 that functions as a condenser. This liquid refrigerant is sent again to the indoor unit 102 via the liquid piping 20. In FIG. 1, reference numeral 9 denotes an outdoor fan that draws outdoor air into the outdoor unit 101 and discharges the outdoor air to the outside of the outdoor unit 101 after heat exchange by the outdoor heat exchanger 3.

[0014] Furthermore, during heating operation, the air conditioner 100 sends high-temperature, high-pressure gas refrigerant from the compressor 7 to the indoor unit 102 via the gas piping 30 by switching the refrigerant flow path with the four-way valve 8 of the outdoor unit 101. At this time, the indoor heat exchanger 4 functions as a condenser to heat the surrounding air. Then, the liquid refrigerant (including gas-liquid two-phase refrigerant) condensed in the heat transfer tube (not shown) of the indoor heat exchanger 4 is sent to the outdoor unit 101 via the liquid piping 20. The liquid refrigerant sent to the outdoor unit 101 passes through the outdoor heat exchanger 3, which functions as an evaporator of the outdoor unit 101, and the compressor 7, and becomes high-temperature, high-pressure gas refrigerant again, and is sent to the indoor unit 102.

[0015] The liquid pipe 20 is composed of a liquid pipe 20b made of copper or a copper alloy and liquid pipes 20a made of aluminum or an aluminum alloy and arranged at both ends of the liquid pipe 20b. The gas pipe 30 is composed of a gas pipe 30b made of copper or a copper alloy and gas pipes 30a made of aluminum or an aluminum alloy and arranged at both ends of the gas pipe 30b.

[0016] <Indoor unit> Next, the indoor unit 102 (see FIG. 1) will be described. As shown in FIG. 1, the indoor heat exchanger 4 of the indoor unit 102 is formed in a substantially U-shape in cross section so as to cover the front and top surfaces of the cross-flow fan 2 which is a blower. The driven cross-flow fan 2 draws indoor air from an inlet (not shown) formed at the top of the housing 1 of the indoor unit 102, passes the air through the indoor heat exchanger 4, and blows it out into the room from the outlet 5 of the housing 1. At this time, the indoor air is cooled or heated by the indoor heat exchanger 4 depending on whether it is heating or cooling. The indoor unit 102 blows out such conditioned air from the outlet 5.

[0017] Fig. 2 is a partially enlarged cross-sectional view schematically showing the state of the connection portion between the indoor heat exchanger 4 and the gas pipe 30. In Fig. 2, the outline arrows marked with the symbol R indicate the direction of refrigerant flow during cooling operation. As shown in FIG. 2, the indoor heat exchanger 4 includes plate-shaped fins 21 and heat transfer tubes 22. A plurality of plate-shaped fins 21 are stacked at predetermined intervals in the thickness direction. In this embodiment, the fins 21 are made of aluminum or an aluminum alloy.

[0018] 2, the heat transfer tubes 22 are formed so as to penetrate the plurality of fins 21 in the stacking direction. In this embodiment, the heat transfer tubes 22 are made of aluminum or an aluminum alloy.

[0019] 2, the gas pipe 30 is a pipe through which the refrigerant R flowing out from the heat transfer tube 22 passes during cooling operation. This gas pipe 30 corresponds to a downstream connecting pipe located downstream of the heat transfer tube 22 in the flow direction of the refrigerant R. As described above, the gas pipe 30 is composed of the gas pipe 30a made of aluminum or an aluminum alloy, and the gas pipe 30b made of copper or a copper alloy.

[0020] The gas pipe 30a is an element pipe whose one end is partially reduced in diameter, and is fitted into the heat transfer tube 22 so that the outer surface of the gas pipe 30a is in contact with the inner surface of the heat transfer tube 22. Specifically, the gas pipe 30a has an inner diameter D 11 The first main pipe portion 30a1 has an inner diameter D 11 The inner diameter D is smaller than 12 The first thin-diameter portion 30a2 has a first thin-diameter portion 30a3. The gas pipe 30a corresponds to the "first pipe." The first main pipe portion 30a1 may have a larger diameter than the base pipe.

[0021] In this embodiment, the first main pipe portion 30a1 has an inner diameter D 11 In this case, a circular pipe with an inner diameter D 11 However, this does not exclude a gas pipe 30a having a first main pipe portion 30a1 that varies somewhat in the extending direction of the pipe. The inner diameter D of the first main pipe portion 30a1 is 11 is a value measured at a position closest to the first small diameter portion 30a2. 11 is the inner diameter of the end of the first main pipe portion 30a1 on the first small diameter portion 30a2 side.

[0022] In addition, the first small diameter portion 30a2 in this embodiment has an inner diameter D 12 In this case, a circular pipe with an inner diameter D 12 However, this does not exclude the gas pipe 30a having the first small diameter portion 30a2 which varies somewhat in the extending direction of the pipe. The inner diameter D of the first small diameter portion 30a2 is 12is the inner diameter D that varies in the extending direction of the first small diameter portion 30a2. 12 It is determined by the smallest value of

[0023] As shown in FIG. 2, the gas pipe 30b has one end of a base pipe that is partially reduced in diameter, and is fitted into the inner surface of the gas pipe 30a (first main pipe portion 30a1) so that the outer surface of the gas pipe 30b is in contact with the inner surface of the gas pipe 30a. Specifically, the gas pipe 30b has an inner diameter D 21 The second main pipe portion 30b1 has an inner diameter D 21 The inner diameter D is smaller than 22 The second thin-diameter portion 30b2 is also provided. The gas pipe 30b corresponds to the "second pipe." The second main pipe portion 30b1 may have a larger diameter than the base pipe.

[0024] In this embodiment, the second main pipe portion 30b1 has an inner diameter D 21 In this case, a circular pipe with an inner diameter D 21 However, this does not exclude the gas pipe 30b having the second main pipe portion 30b1 which varies somewhat in the extending direction of the pipe. The inner diameter D of the second main pipe portion 30b1 is 21 is a value measured at a position closest to the second thin diameter portion 30b2. 21 is the inner diameter of the end of the second main pipe portion 30b1 on the second small diameter portion 30b2 side.

[0025] In addition, the second small diameter portion 30b2 in this embodiment has an inner diameter D 22 In this case, a circular pipe with an inner diameter D 22 However, this does not exclude the gas pipe 30b having the second small diameter portion 30b2 which varies somewhat in the extending direction of the pipe. The inner diameter D of the second small diameter portion 30b2 is 22 is the inner diameter D that varies in the extending direction of the second thin diameter portion 30b2. 22 It is determined by the smallest value of

[0026] In the gas pipe 30 (downstream connection pipe) as described above, the inner diameter D of the first main pipe section 30a1 of the gas pipe 30a (first pipe) 11 The inner diameter D of the first small diameter portion 30a2 12 Divided by (inner diameter D 11 / Inner diameter D 12 The value of the inner diameter D of the second main pipe portion 30b1 of the gas pipe 30b (second pipe) 21 The inner diameter D of the second small diameter portion 30b2 22 Divided by (inner diameter D 21 / Inner diameter D 22 That is, the gas pipe 30a (first pipe) and the gas pipe 30b (second pipe) have an inner diameter D 11 / Inner diameter D 12 <Inner diameter D 21 / Inner diameter D 22 The following relation is satisfied.

[0027] In addition, in the gas pipe 30 (downstream connection pipe), the inner diameter D of the first main pipe portion 30a1 in the gas pipe 30a (first pipe) 11 The inner diameter D of the second small diameter portion 30b2 of the gas pipe 30b (second pipe) 22 Divided by (inner diameter D 11 / Inner diameter D 22 The value of the inner diameter D of the second main pipe portion 30b1 of the gas pipe 30b (second pipe) 21 The inner diameter D of the second small diameter portion 30b2 22 Divided by (inner diameter D 21 / Inner diameter D 22 That is, the gas pipe 30a (first pipe) and the gas pipe 30b (second pipe) have an inner diameter D 11 / Inner diameter D 22 <Inner diameter D 21 / Inner diameter D 22 The following relation is satisfied. In addition, in the gas pipe 30 (downstream connection pipe), the wall thickness T 21 However, the thickness T of the first main pipe portion 30a1 of the gas pipe 30a (first pipe) 11 It is more than one-third of the

[0028] Next, the liquid piping 20 (see FIG. 1) in this embodiment will be described in more detail. 3 is a partially enlarged cross-sectional view schematically illustrating the connection between the indoor heat exchanger 4 (see FIG. 1) and the liquid piping 20 (see FIG. 1). In FIG. 3, the outline arrows labeled R indicate the direction of refrigerant flow during cooling operation.

[0029] 3, the liquid piping 20 is a piping through which the refrigerant R flows into the heat transfer tubes 22 during cooling operation. The liquid piping 20 corresponds to an upstream connecting piping located upstream of the heat transfer tubes 22 in the flow direction of the refrigerant R. As described above, the liquid pipe 20 is composed of the liquid pipe 20a made of aluminum or an aluminum alloy, and the liquid pipe 20b made of copper or a copper alloy.

[0030] The liquid pipe 20a has one end of a base pipe that is partially reduced in diameter, and is fitted into the heat transfer tube 22 so that the outer surface of the liquid pipe 20a comes into contact with the inner surface of the heat transfer tube 22. Specifically, the liquid pipe 20a has an inner diameter D 31 The third main pipe portion 20a1 has an inner diameter D 31 The inner diameter D is smaller than 32 The third thin-diameter portion 20a2 is also included. The liquid pipe 20a corresponds to the "third pipe." The third main pipe portion 20a1 may have a larger diameter than the base pipe.

[0031] In this embodiment, the third main pipe portion 20a1 has an inner diameter D 31 In this case, a circular pipe with an inner diameter D 31 However, this does not exclude the liquid pipe 20a having a third main pipe portion 20a1 that varies somewhat in the extending direction of the pipe. The inner diameter D of the third main pipe portion 20a1 is 31 is a value measured at a position closest to the third thin diameter portion 20a2. 31 is the inner diameter of the end of the third main pipe portion 20a1 on the third small diameter portion 20a2 side.

[0032] In addition, the third small diameter portion 20a2 in this embodiment has an inner diameter D 32 In this case, a circular pipe with an inner diameter D 32 However, this does not exclude the liquid pipe 20a having the third small diameter portion 20a2 which varies somewhat in the extending direction of the pipe. The inner diameter D of the third small diameter portion 20a2 is 32 is the inner diameter D that varies in the extending direction of the third thin diameter portion 20a2. 32 It is determined by the smallest value of

[0033] As shown in Figure 3, one end of the liquid pipe 20b is a bare pipe whose diameter is partially reduced, and the liquid pipe 20b is fitted into the inner surface of the liquid pipe 20a (third main pipe section 20a1) so that the outer surface of the liquid pipe 20b is in contact with the inner surface of the liquid pipe 20a. Specifically, the liquid pipe 20b has an inner diameter D 41 The fourth main pipe portion 20b1 and the inner diameter D 41 The inner diameter D is smaller than 42 The fourth thin-diameter portion 20b2 is also included. The liquid pipe 20b corresponds to the "fourth pipe." The fourth main pipe portion 20b1 may have a larger diameter than the base pipe.

[0034] In this embodiment, the fourth main pipe portion 20b1 has an inner diameter D 41 In this case, a circular pipe with an inner diameter D 41 However, this does not exclude the liquid pipe 20b having a fourth main pipe portion 20b1 that varies somewhat in the extending direction of the pipe. The inner diameter D of the fourth main pipe portion 20b1 is 41 is a value measured at a position closest to the fourth small diameter portion 20b2. 41 is the inner diameter of the end of the fourth main pipe portion 20b1 on the side of the fourth small diameter portion 20b2.

[0035] In addition, the fourth small diameter portion 20b2 in this embodiment has an inner diameter D 42 In this case, a circular pipe with an inner diameter D 42However, this does not exclude the liquid pipe 20b having a fourth small diameter portion 20b2 that varies somewhat in the extending direction of the pipe. The inner diameter D of the fourth small diameter portion 20b2 is 42 is the inner diameter D that varies in the extending direction of the fourth thin diameter portion 20b2. 22 It is determined by the smallest value of

[0036] In the liquid piping 20 (upstream connecting piping) as described above, the inner diameter D of the third main pipe portion 20a1 of the liquid piping 20a (third piping) 31 The inner diameter D of the third small diameter portion 20a2 32 Divided by (inner diameter D 31 / Inner diameter D 32 The value of the inner diameter D of the fourth main pipe portion 20b1 of the liquid pipe 20b (fourth pipe) 41 The inner diameter D of the fourth small diameter portion 20b2 42 Divided by (inner diameter D 41 / Inner diameter D 42 That is, the liquid pipe 20a (third pipe) and the liquid pipe 20b (fourth pipe) have an inner diameter D 31 / Inner diameter D 32 <Inner diameter D 41 / Inner diameter D 42 The following relation is satisfied.

[0037] In addition, in the liquid piping 20 (upstream side connecting piping), the inner diameter D of the third main pipe portion 20a1 in the liquid piping 20a (third piping) 31 The inner diameter D of the fourth small diameter portion 20b2 of the liquid pipe 20b (fourth pipe) 42 Divided by (inner diameter D 31 / Inner diameter D 42 The value of the inner diameter D of the fourth main pipe portion 20b1 of the liquid pipe 20b (fourth pipe) 41 The inner diameter D of the fourth small diameter portion 20b2 42 Divided by (inner diameter D 41 / Inner diameter D 42 That is, the liquid pipe 20a (third pipe) and the liquid pipe 20b (fourth pipe) have an inner diameter D 31 / Inner diameter D 42 <Inner diameter D 41 / Inner diameter D 42 The following relation is satisfied.

[0038] In addition, in the liquid piping 20 (upstream side connecting piping), the thickness T 41 However, the thickness T of the third main pipe portion 20a1 of the liquid pipe 20a (third pipe) 31 It is more than one-third of the

[0039] <Action and effect> Next, the effects and advantages achieved by the air conditioner 100 of this embodiment will be described. As mentioned above, when aluminum pipes are used in indoor units, the refrigerant noise generated by the flowing refrigerant increases. Generally, when connecting dissimilar materials, such as aluminum and copper pipes, one pipe is inserted inside the other pipe to connect them. Therefore, in such a connecting pipe, the cross-sectional area of ​​one pipe differs from that of the other pipe. When such a change in cross-sectional area occurs in the connecting pipe, so-called refrigerant noise occurs due to energy loss of the refrigerant flowing inside the connecting pipe. The inventors arrived at the air conditioner 100 of this embodiment based on the finding that piping made of aluminum, which has a lower density than copper, is more likely to produce refrigerant noise than copper pipes.

[0040] The air conditioner 100 of this embodiment comprises a heat transfer tube 22 made of aluminum or an aluminum alloy and constituting at least a part of the flow path of the refrigerant R in the indoor heat exchanger 4, and a gas pipe 30 (downstream connecting pipe) located downstream of the flow of the refrigerant R with respect to the heat transfer tube 22 during cooling operation. The gas pipe 30 (downstream connecting pipe) has an inner diameter D 11 and a first main pipe portion 30a1, at least a portion of which is located inside the heat transfer pipe 22, and has an inner diameter D 12 a gas pipe 30a (first pipe) made of aluminum or an aluminum alloy and having an inner diameter D 21 and a second main pipe portion 30b1, at least a part of which is located inside the gas pipe 30a (first pipe), and has an inner diameter D 22and a gas pipe 30b (second pipe) formed of copper or a copper alloy, and having an inner diameter D 12 is the inner diameter D 11 is less than or equal to the inner diameter D 22 is the inner diameter D 21 Smaller and inner diameter D 11 / Inner diameter D 12 The value of the inner diameter D 21 / Inner diameter D 22 For convenience, the term "thin diameter portion" is used, but the inner diameter D of the first thin diameter portion 30a2 is smaller than the value 12 is the inner diameter D of the first main pipe portion 30a1 11 In this case, the gas pipe 30 located inside the heat transfer tube 22 is the first small diameter portion 30a2, and the gas pipe 30 not located inside the heat transfer tube 22 is the first main pipe portion 30a1. On the other hand, in this embodiment, the inner diameter D of the second small diameter portion 30b2 22 The inner diameter D of the second main pipe portion 30b1 21 does not include those with the same value.

[0041] According to this air conditioner 100, by making the change in the cross-sectional area of ​​the gas pipe 30a (first pipe) made of aluminum or aluminum alloy, which is more likely to emit refrigerant noise, smaller than the change in the cross-sectional area of ​​the gas pipe 30b (second pipe) made of copper or copper alloy, it is possible to suppress the generation of refrigerant noise in the indoor unit 102. Specifically, it is possible to suppress the generation of refrigerant noise in the gas pipe 30 (downstream connecting pipe) located downstream of the indoor heat exchanger 4 in the flow of the refrigerant R.

[0042] Furthermore, in the gas pipe 30a (first pipe) of such an air conditioner 100, energy loss occurs in the refrigerant flowing not only when the cross-sectional area increases from the connection side with the heat transfer pipe 22 to the first main pipe portion 30a1 side, but also when the cross-sectional area decreases. This energy loss then causes refrigerant noise. The air conditioner 100 of this embodiment has an inner diameter D 11 / Inner diameter D 22 The value of the inner diameter D 21 / Inner diameter D 222. The air conditioner according to claim 1, wherein the value is smaller than the value of According to this air conditioner 100, it is possible to more reliably suppress the generation of refrigerant noise in the gas pipe 30 (downstream connecting pipe).

[0043] The air conditioner 100 of this embodiment comprises a heat transfer tube 22 made of aluminum or an aluminum alloy and constituting at least a part of the flow path of the refrigerant R in the indoor heat exchanger 4, and a liquid pipe 20 (upstream connecting pipe) located upstream of the flow of the refrigerant R with respect to the heat transfer tube 22 during cooling operation. The liquid pipe 20 (upstream connecting pipe) has an inner diameter D 31 and a third main pipe portion 20a1, at least a portion of which is located inside the heat transfer pipe 22 and has an inner diameter D 32 and a third small diameter portion 20a2, which is a liquid pipe 20a (third pipe) made of aluminum or an aluminum alloy, and an inner diameter D 41 and a fourth main pipe portion 20b1, at least a part of which is located inside the liquid pipe 20a (third pipe), and has an inner diameter D 42 and a fourth small diameter portion 20b2, which is a liquid pipe 20b (fourth pipe) made of copper or a copper alloy, and has an inner diameter D 32 is the inner diameter D 31 is less than or equal to the inner diameter D 42 is the inner diameter D 41 Smaller and inner diameter D 31 / Inner diameter D 32 The value of the inner diameter D 41 / Inner diameter D 42 For convenience, the term "thin diameter portion" is used, but the inner diameter D of the third thin diameter portion 20a2 is smaller than the value 32 is the inner diameter D of the third main pipe portion 20a1 31 In this case, the liquid pipe 20 located inside the heat transfer tube 22 is the third small diameter section 20a2, and the liquid pipe 20 not located inside the heat transfer tube 22 is the third main pipe section 20a1. On the other hand, in this embodiment, the inner diameter D 42 The inner diameter D of the fourth main pipe portion 20b1 41 does not include those with the same value. According to this air conditioner 100, the generation of refrigerant noise in the liquid piping 20 (upstream connecting piping) located upstream of the indoor heat exchanger 4 in the flow of the refrigerant R can be suppressed.

[0044] In addition, such an air conditioner 100 has an inner diameter D 31 / Inner diameter D 42 The value of the inner diameter D 41 / Inner diameter D 42 is smaller than the value of According to this air conditioner 100, it is possible to more reliably suppress the generation of refrigerant noise in the liquid piping 20 (upstream connecting piping).

[0045] Furthermore, in the air conditioner 100 of this embodiment, the surface density [density x pipe wall thickness] of the second main pipe portion 30b1 is greater than the surface density [density x pipe wall thickness] of the first main pipe portion 30a1. In this air conditioner 100, if the surface density of the gas pipe 30b (second pipe) made of copper or copper alloy is greater than that of the gas pipe 30a (first pipe) made of aluminum or aluminum alloy, the refrigerant noise in the gas pipe 30a (first pipe) is more likely to resonate. Note that the density of aluminum is about one-third of the density of copper. In addition, in the air conditioner 100 of this embodiment, the wall thickness T 21 However, the thickness T of the first main pipe portion 30a1 of the gas pipe 30a (first pipe) 11 It is more than one-third of the According to this air conditioner 100, the generation of refrigerant noise in the gas piping 30 (downstream connecting piping) can be more reliably suppressed.

[0046] Furthermore, in the air conditioner 100 of this embodiment, the surface density [density × pipe wall thickness] of the fourth main pipe portion 20b1 is greater than the surface density [density × pipe wall thickness] of the third main pipe portion 20a1. In this air conditioner 100, if the surface density [density × pipe wall thickness] of liquid pipe 20b (fourth pipe) made of copper or copper alloy is greater than that of liquid pipe 20a (third pipe) made of aluminum or aluminum alloy, the refrigerant noise in liquid pipe 20a (third pipe) is more likely to resonate. Note that the density of aluminum is about one-third the density of copper.

[0047] In addition, in the air conditioner 100, the thickness T 41 However, the thickness T of the third main pipe portion 20a1 of the liquid pipe 20a (third pipe) 31 It is more than one-third of the According to this air conditioner 100, the generation of refrigerant noise in the liquid piping 20 (upstream connecting piping) can be more reliably suppressed.

[0048] In addition, in such an air conditioner 100, the inner diameter D of the first main pipe portion 30a1 11 is the inner diameter D of the second main pipe portion 30b1 21 The inner diameter D of the second main pipe portion 30b1 is smaller than the inner diameter D of the second main pipe portion 30b1. 21 is smaller than the inner diameter of the heat transfer tube 22.

[0049] According to this air conditioner 100, the inner diameter of the gas pipe 30a (first pipe) arranged between the heat transfer pipe 22 and the gas pipe 30b (second pipe) gradually changes when set between the inner diameter of the heat transfer pipe 22 and the inner diameter of the gas pipe 30b (second pipe). This may be thought to reduce the pressure loss of the air conditioner 100. However, in reality, the refrigerant noise increased due to the increase in the reduction ratio of the gas pipe 30a (first pipe). For this reason, the inner diameter D of the first main pipe section 30a1 is deliberately set to 11 By reducing the diameter of the gas pipe 30a (first pipe), the contraction rate of the gas pipe 30a (first pipe) was reduced.

[0050] In addition, in such an air conditioner 100, the inner diameter D of the third main pipe portion 20a1 31 is the inner diameter D of the fourth main pipe portion 20b1 41 The inner diameter D of the fourth main pipe portion 20b1 is smaller than the inner diameter D of the fourth main pipe portion 20b1. 41is smaller than the inner diameter of the heat transfer tube 22.

[0051] According to this air conditioner 100, the inner diameter of the liquid pipe 20a (third pipe) arranged between the heat transfer pipe 22 and the liquid pipe 20b (fourth pipe) gradually changes when set between the inner diameter of the heat transfer pipe 22 and the inner diameter of the liquid pipe 20b (fourth pipe). This may be thought to reduce the pressure loss of the air conditioner 100. However, in reality, the refrigerant noise increased due to the increase in the reduction ratio of the liquid pipe 20a (third pipe). For this reason, the inner diameter D of the third main pipe section 20a1 was deliberately set to 31 By reducing the diameter, the contraction rate of the liquid pipe 20a (third pipe) was reduced.

[0052] In addition, in such an air conditioner 100, the inner diameter D of the first small diameter portion 30a2 12 is the inner diameter D of the second small diameter portion 30b2 22 Greater than. According to this air conditioner 100, in addition to the reduction ratio of the first small diameter portion 30a2 in the gas pipe 30a (first pipe), the inner diameter D 12 By increasing the value itself, the generation of refrigerant noise can be suppressed.

[0053] In addition, in such an air conditioner 100, the inner diameter D of the third small diameter portion 20a2 32 is the inner diameter D of the fourth small diameter portion 20b2 42 Greater than. According to this air conditioner 100, in addition to the reduction ratio of the third small diameter portion 20a2 in the liquid pipe 20a (third pipe), the inner diameter D 32 By increasing the value itself, the generation of refrigerant noise can be suppressed.

[0054] In addition, in such an air conditioner 100, the inner diameter D 11 is the inner diameter of the end of the first main pipe portion 30a1 on the first small diameter portion 30a2 side, and the inner diameter D 12 is the smallest inner diameter of the first small diameter portion 30a2, and the inner diameter D 21is the inner diameter of the end of the second main pipe portion 30b1 on the second small diameter portion 30b2 side, and the inner diameter D 22 is the smallest inner diameter of the second small diameter portion 30b2. According to this air conditioner 100, the generation of refrigerant noise can be more reliably suppressed.

[0055] In addition, in such an air conditioner 100, the inner diameter D 31 is the inner diameter of the end of the third main pipe portion 20a1 on the third small diameter portion 20a2 side, and the inner diameter D 32 is the smallest inner diameter of the third thin-diameter portion 20a2, and the inner diameter D 41 is the inner diameter of the end of the fourth main pipe portion 20b1 on the side of the fourth small diameter portion 20b2, and the inner diameter D 42 is the smallest inner diameter of the fourth small diameter portion 20b2. According to this air conditioner 100, the generation of refrigerant noise can be more reliably suppressed.

[0056] Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and can be embodied in various forms. In the embodiment, as shown in FIG. 2, the inner diameter D of the first small diameter portion 30a2 of the gas pipe 30 (downstream side connection pipe) 12 It is assumed that the inner diameter D of the second small diameter portion 30b2 is constant in the longitudinal direction of this piping portion. 22 It is also assumed that the length is constant. However, at least one of the first thin diameter portion 30a2 and the second thin diameter portion 30b2 can be formed in a tapered shape. In the above embodiment, the inner diameter D of the first small diameter portion 30a2 12 is the inner diameter D of the first main pipe portion 30a1 11 The inner diameter D of the first small diameter portion 30a2 is as follows: 12 is the inner diameter D of the first main pipe portion 30a1 11 Smaller configurations are also possible. In the above embodiment, the inner diameter D of the third small diameter portion 20a2 32is the inner diameter D of the third main pipe portion 20a1 11 The third small diameter portion 20a2 has the following inner diameter D 32 is the inner diameter D of the third main pipe portion 20a1 31 Smaller configurations are also possible.

[0057] Fig. 4 is a partially enlarged cross-sectional view schematically showing a connection pipe structure in another embodiment, in which the reduced diameter portion Pb2 of the second pipe Pb is fitted into the inside of the bare pipe portion Pa1 of the first pipe Pa. The reduced diameter portion Pb2 of the second pipe Pb is formed in a tapered shape so that the diameter gradually decreases as it extends from the base pipe portion Pb1 of the second pipe Pb to the tip. The second pipe Pb in Fig. 4 corresponds to the first main pipe section 30a1 of the gas pipe 30a (first pipe) shown in Fig. 2. The first pipe Pa in Fig. 4 corresponds to the heat transfer tube 22 shown in Fig. 2. The inner diameter D of the first small diameter portion 30a2 shown in FIG. 12 corresponds to the smallest inner diameter D2 at the tip of the tapered reduced diameter portion Pb2 shown in FIG. 4, and is the smallest inner diameter D of the first main pipe portion 30a1 shown in FIG. 11 corresponds to the inner diameter D1 at the mother tube portion Pb1 that is closest to the tapered diameter-reduced portion Pb2 shown in FIG.

[0058] 4 corresponds to the second main pipe section 30b1 of the gas pipe 30b (second pipe) shown in Fig. 2. The first pipe Pa in Fig. 4 corresponds to the first main pipe section 30a1 of the gas pipe 30a (first pipe) shown in Fig. 2. The inner diameter D of the second small diameter portion 30b2 shown in FIG. 22 corresponds to the smallest inner diameter D2 at the tip of the tapered reduced diameter portion Pb2 shown in FIG. 4, and is the smallest inner diameter D of the second main pipe portion 30b1 shown in FIG. 21 corresponds to the inner diameter D1 at the mother tube portion Pb1 that is closest to the tapered diameter-reduced portion Pb2 shown in FIG.

[0059] The tapered connection pipe structure shown in FIG. 4 can also be applied to the liquid pipe 20 (upstream connection pipe) shown in FIG. That is, the second pipe Pb in Fig. 4 corresponds to the third main pipe section 20a1 of the liquid pipe 20a (third pipe) shown in Fig. 3. The first pipe Pa in Fig. 4 corresponds to the heat transfer pipe 22 shown in Fig. 3. The inner diameter D of the third small diameter portion 20a2 shown in FIG. 32 corresponds to the smallest inner diameter D2 at the tip of the tapered reduced diameter portion Pb2 shown in FIG. 4, and is the smallest inner diameter D of the third main pipe portion 20a1 shown in FIG. 31 corresponds to the inner diameter D1 at the mother tube portion Pb1 that is closest to the tapered diameter-reduced portion Pb2 shown in FIG.

[0060] Also, the second pipe Pb in Fig. 4 corresponds to the fourth main pipe section 20b1 of the liquid pipe 20b (fourth pipe) shown in Fig. 3. The first pipe Pa in Fig. 4 corresponds to the third main pipe section 20a1 of the liquid pipe 20a (third pipe) shown in Fig. 3. The inner diameter D of the fourth small diameter portion 20b2 shown in FIG. 42 corresponds to the smallest inner diameter D2 at the tip of the tapered reduced diameter portion Pb2 shown in FIG. 4, and is the smallest inner diameter D of the fourth main pipe portion 20b1 shown in FIG. 41 corresponds to the inner diameter D1 at the mother tube portion Pb1 that is closest to the tapered diameter-reduced portion Pb2 shown in FIG.

[0061] In the embodiment, in the joint structure between the heat transfer tube 22 and the gas pipe 30 (downstream connection pipe), as shown in FIG. 11 / Inner diameter D 12 The value of exceeds 1 (inner diameter D 11 / Inner diameter D 12 >1), but the present invention assumes an inner diameter D 11 and inner diameter D 12 and are equal (inner diameter D 11 / Inner diameter D 12 =1) is not excluded. In addition, in the joint structure between the heat transfer tube 22 and the liquid pipe 20 (downstream connecting pipe), as shown in FIG. 31 / Inner diameter D 32 The value of exceeds 1 (inner diameter D 31 / Inner diameter D 32 >1), but the present invention assumes an inner diameter D 31and inner diameter D 32 and are equal (inner diameter D 31 / Inner diameter D 32 =1) is not excluded.

[0062] In the above embodiment, the inlet and outlet of the indoor heat exchanger 4 are configured with one path as shown in Figures 2 and 3, but the inlet and outlet of the indoor heat exchanger may be configured with multiple paths. For example, a piping structure may be adopted in which the gas piping 30a (first piping) shown in Figure 2 and the liquid piping 20a (third piping) shown in Figure 3 have a junction / branch pipe.

[0063] Fig. 5 is a partially enlarged cross-sectional view schematically showing a modified example of the gas pipe 30a (see Fig. 2) as the first pipe constituting the downstream connecting pipe. In Fig. 5, reference numeral 21 denotes fins of the indoor heat exchanger 4, reference numeral 22 denotes heat transfer tubes made of aluminum or an aluminum alloy, and reference numeral R denotes a refrigerant.

[0064] 5, the gas piping 30a (first piping) according to the modified example includes a first main pipe section 30a1 which is a two-path outlet pipe from the indoor heat exchanger 4, and a first main pipe section 30a1 which is a junction pipe where these outlet pipes join together. Each of the first main pipe sections 30a1 which are two-path outlet pipes is connected to the heat transfer pipes 22 of the indoor heat exchanger 4 via a first small diameter section 30a2. That is, at least a portion of the first small diameter section 30a2 is located inside the heat transfer pipe 22. Such gas pipe 30a (first pipe) is made of aluminum or an aluminum alloy.

[0065] The gas pipe 30b (second pipe) is formed of copper or a copper alloy and has a second main pipe portion 30b1 and a second narrow diameter portion 30b2, at least a portion of which is located inside the first main pipe portion 30a1, which is a junction pipe. As shown in FIG. 5, the inner diameter D 11 is determined by the inner diameter of the end of the first main pipe portion 30a1, which is the outlet pipe, on the side of the first small diameter portion 30a2. 12is determined by the smallest inner diameter of the first small diameter portion 30a2. 21 is determined by the inner diameter of the end of the second main pipe portion 30b1 on the second small diameter portion 30b2 side. 22 is determined by the smallest inner diameter of the second thin diameter portion 30b2.

[0066] And the inner diameter D 12 is the inner diameter D 11 is less than or equal to the inner diameter D 22 is the inner diameter D 21 Smaller and inner diameter D 11 / Inner diameter D 12 The value of the inner diameter D 21 / Inner diameter D 22 Also, the inner diameter D 11 is the inner diameter D 21 Smaller and inner diameter D 21 is smaller than the inner diameter of the heat transfer tube. 12 is the inner diameter D 22 Greater than. According to such a modified example, it is possible to diversify the downstream connecting piping structure that suppresses the generation of refrigerant noise.

[0067] Fig. 6 is a partially enlarged cross-sectional view schematically showing a modified example of the liquid pipe 20a (see Fig. 3) as the third pipe constituting the upstream connecting pipe. In Fig. 6, reference numeral 21 denotes a fin of the indoor heat exchanger 4, reference numeral 22 denotes a heat transfer tube made of aluminum or an aluminum alloy, and reference numeral R denotes a refrigerant.

[0068] 6, the liquid piping 20a (third piping) according to the modified example has a third main pipe section 20a1 which is a two-path inlet pipe (branch pipe) to the indoor heat exchanger 4, and a third main pipe section 20a1 which is the branching source of these inlet pipes. Each of the third main pipe sections 20a1 which are two-path inlet pipes is connected to a heat transfer pipe 22 of the indoor heat exchanger 4 via a third small diameter section 20a2. That is, at least a portion of the third small diameter section 20a2 is located inside the heat transfer pipe 22. Such liquid pipe 20a (third pipe) is made of aluminum or an aluminum alloy.

[0069] The liquid pipe 20b (fourth pipe) is formed of copper or a copper alloy and has a fourth main pipe section 20b1 and a fourth narrow diameter section 20b2, at least a portion of which is located inside the third main pipe section 20a1 from which it branches. As shown in FIG. 6, the inner diameter D 31 is determined by the inner diameter of the end of the third main pipe portion 20a1, which is the inlet pipe (branch pipe), on the third small diameter portion 20a2 side. 32 is determined by the smallest inner diameter of the third small diameter portion 20a2. 41 is determined by the inner diameter of the end of the fourth main pipe portion 20b1 on the side of the fourth small diameter portion 20b2. 42 is determined by the smallest inner diameter of the fourth thin diameter portion 20b2.

[0070] And the inner diameter D 32 is the inner diameter D 31 is less than or equal to the inner diameter D 42 is the inner diameter D 41 Smaller and inner diameter D 31 / Inner diameter D 32 The value of the inner diameter D 41 / Inner diameter D 42 Also, the inner diameter D 31 is the inner diameter D 41 Smaller and inner diameter D 41 is smaller than the inner diameter of the heat transfer tube. 32 is the inner diameter D 42 Greater than. According to such a modified example, it is possible to diversify the upstream connecting piping structure that suppresses the generation of refrigerant noise.

[0071] 2 and 5, the connection between the heat transfer tube 22 and the gas pipe 30a (first pipe) is configured such that a part of the first small diameter portion 30a2 is located inside the heat transfer tube 22. In the example shown in FIG. However, in the air conditioner 100 of the present invention, although not shown in the drawings, the first small diameter portion 30a2 may be configured to be entirely located inside the heat transfer tube 22. Furthermore, as shown in Figure 7, which shows another connection mode between the heat transfer tube 22 and the gas pipe 30a (first pipe), the tip of the first main pipe section 30a1 can be positioned inside the heat transfer tube 22, so that the entire first narrow diameter section 30a2 can be positioned inside the heat transfer tube 22.

[0072] 3 and 6, the connection between the heat transfer tube 22 and the liquid piping 20a (third piping) is configured such that a part of the third small diameter portion 20a2 is located inside the heat transfer tube 22. However, although not shown in the drawings, the air conditioner 100 of the present invention may also be configured so that the entire third small diameter portion 20a2 is located inside the heat transfer pipe 22. Furthermore, although not shown in the drawings, the tip of the third main pipe portion 20a1 may be located inside the heat transfer pipe 22, so that the entire third small diameter portion 20a2 is located inside the heat transfer pipe 22. [Explanation of symbols]

[0073] 3 Outdoor heat exchanger 4 Indoor heat exchanger 20 Liquid piping (upstream connecting piping) 20a Liquid piping (third piping) 20b Liquid piping (fourth piping) 20a1 Third Main Division 20a2 Third narrow diameter section 20b1 Fourth Main Division 20b2 Fourth narrow diameter portion 21 Finn 22 Heat transfer tube 30 Gas piping (downstream connection piping) 30a Gas piping (first piping) 30b Gas piping (second piping) 30a1 First Main Section 30a2 first narrow diameter portion 30b1 Second Main Division 30b2 second narrow diameter portion 100 Air conditioner 101 Outdoor Unit 102 indoor units R refrigerant

Claims

1. a heat transfer tube that forms at least a part of a refrigerant flow path of the indoor heat exchanger and is made of aluminum or an aluminum alloy; a downstream connection pipe located downstream of the heat transfer pipe in the refrigerant flow direction during cooling operation, The downstream connecting pipe is Inner diameter D １１ a first main pipe portion at least partially located inside the heat transfer tube and having an inner diameter D １２ a first pipe formed of aluminum or an aluminum alloy and having a first narrow diameter portion which is Inner diameter D ２１ a second main pipe portion at least partially located inside the first pipe and having an inner diameter D ２２ a second pipe formed of copper or a copper alloy and having a second thin diameter portion, Equipped with Inner diameter D １２ is the inner diameter D １１ and the inner diameter D ２２ is the inner diameter D ２１ smaller and the inner diameter D １１ / Inner diameter D １２ The value of the inner diameter D ２１ / Inner diameter D ２２ Air conditioners with values ​​smaller than this.

2. Inner diameter D １１ / Inner diameter D ２２ The value of the inner diameter D ２１ / Inner diameter D ２２ 2. The air conditioner according to claim 1, wherein the value of the temperature is smaller than the value of the temperature.

3. a heat transfer tube that forms at least a part of a refrigerant flow path of the indoor heat exchanger and is made of aluminum or an aluminum alloy; an upstream connection pipe located upstream of the heat transfer pipe in the refrigerant flow direction during cooling operation, The upstream connecting pipe is Inner diameter D ３１ a third main pipe portion at least partially located inside the heat transfer tube and having an inner diameter D ３２ a third pipe having a third narrow diameter portion formed of aluminum or an aluminum alloy; Inner diameter D ４１ a fourth main pipe portion at least partly located inside the third pipe and having an inner diameter D ４２ a fourth pipe formed of copper or a copper alloy and having a fourth thin diameter portion, Equipped with Inner diameter D ３２ is the inner diameter D ３１ and the inner diameter D ４２ is the inner diameter D ４１ smaller and the inner diameter D ３１ / Inner diameter D ３２ The value of the inner diameter D ４１ / Inner diameter D ４２ Air conditioners with values ​​smaller than this.

4. Inner diameter D ３１ / Inner diameter D ４２ The value of the inner diameter D ４１ / Inner diameter D ４２ 4. The air conditioner according to claim 3, wherein the value of

5. The wall thickness T of the second main pipe portion ２１ The thickness T of the first main pipe portion １１ 3. The air conditioner according to claim 1, wherein the temperature is 1 / 3 or more of the above.

6. 3. The air conditioner according to claim 1, wherein the surface density of the second main pipe portion is greater than the surface density of the first main pipe portion.

7. The thickness T of the fourth main pipe portion ４１ The thickness T of the third main pipe portion ３１ 4. The air conditioner according to claim 3, wherein the temperature is at least one-third of the above.

8. 4. The air conditioner according to claim 3, wherein the surface density of the fourth main pipe portion is greater than the surface density of the third main pipe portion.

9. The inner diameter D of the first main pipe portion １１ is the inner diameter D of the second main pipe portion ２１ and the inner diameter D of the second main pipe section is smaller than ２１ 3. The air conditioner according to claim 1, wherein the inner diameter of the heat transfer tube is smaller than the inner diameter of the heat transfer tube.

10. The inner diameter D of the third main pipe portion ３１ is the inner diameter D of the fourth main pipe portion ４１ and the inner diameter D of the fourth main pipe section is smaller than ４１ 4. The air conditioner according to claim 3, wherein the inner diameter of the heat transfer tube is smaller than the inner diameter of the heat transfer tube.

11. The inner diameter D of the first narrow diameter portion １２ is the inner diameter D of the second narrow diameter portion ２２ 3. The air conditioner according to claim 1, wherein the air conditioner is larger than the air conditioner in claim 1.

12. The inner diameter D of the third narrow diameter portion ３２ is the inner diameter D of the fourth narrow diameter portion ４２ 4. The air conditioner according to claim 3, wherein the air conditioner is larger than the air conditioner.

13. Inner diameter D １１ is the inner diameter of the end of the first main pipe portion on the side of the first small diameter portion, and the inner diameter D １２ is the inner diameter of the first narrow diameter portion at a location where the inner diameter is smallest, Inner diameter D ２１ is the inner diameter of the end of the second main pipe portion on the second small diameter portion side, and the inner diameter D ２２ 3. The air conditioner according to claim 1, wherein the inner diameter of the second small diameter portion is the smallest.

14. Inner diameter D ３１ is the inner diameter of the end of the third main pipe portion on the third small diameter portion side, and the inner diameter D ３２ is the inner diameter of the third thin diameter portion at a location where the inner diameter is smallest, Inner diameter D ４１ is the inner diameter of the end of the fourth main pipe portion on the side of the fourth small diameter portion, and the inner diameter D ４２ 5. The air conditioner according to claim 4, wherein the inner diameter of the fourth narrow diameter portion is the smallest.

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