Air conditioner

Abstract

The invention provides an air conditioner which suppresses generation of refrigerant sound in an indoor unit. This air conditioner is provided with downstream-side connection piping that is located downstream of the flow of a refrigerant (R) with respect to a heat transfer pipe (22) during cooling operation. The downstream-side connection piping is provided with: a gas piping (30a) (first piping) that is formed from an aluminum alloy and that has a first main pipe section (30a1) having an inner diameter D11 and a first small-diameter section (30a2) having an inner diameter D12 and at least a part of which is positioned inside the heat transfer pipe (22); and a gas pipe (30b) (second pipe) formed from a copper alloy, the gas pipe (30b) having a second main pipe section (30b1) having an inner diameter D21 and a second small-diameter section (30b2) having an inner diameter D22 and at least a part of which is positioned on the inside of the gas pipe (30a) (first pipe). The inner diameter D12 is equal to or less than the inner diameter D11, the inner diameter D22 is smaller than the inner diameter D21, and the value of the inner diameter D11 / the inner diameter D12 is smaller than the value of the inner diameter D21 / the inner diameter D22.

Description

Technical Field

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

[0002] Recently, an air conditioner using aluminum tubes in an outdoor heat exchanger is known (for example, see Patent Document 1).

[0003] According to this air conditioner, in an outdoor unit that has conventionally mainly used copper tubes, aluminum tubes that are cheaper than copper tubes are used, thereby reducing the manufacturing cost of the air conditioner.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2023-013765 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] However, it is also considered to achieve further reduction in manufacturing cost by also using aluminum tubes in the indoor unit of the air conditioner.

[0009] However, it has been found that using aluminum tubes in indoor units creates a new problem: the refrigerant noise generated in the indoor unit due to the flowing refrigerant increases. Such air conditioners may suffer from the quietness and stability of the room due to the refrigerant noise generated.

[0010] An object of the present invention is to provide an air conditioner capable of suppressing the occurrence of refrigerant noise in an indoor unit.

[0011] Solutions to Problems

[0012] The air conditioner of the present invention comprises: a heat transfer pipe constituting at least a portion of a refrigerant flow path of an indoor heat exchanger and formed of aluminum or an aluminum alloy; and a downstream connecting pipe located downstream of the refrigerant flow relative to the heat transfer pipe during cooling operation, the downstream connecting pipe comprising: a first pipe having an inner diameter D 11 The first main pipe portion and at least a portion thereof are located inside the heat conducting pipe and have an inner diameter of D 12 The first thin-diameter portion is formed of aluminum or an aluminum alloy; and a second pipe having an inner diameter of D 21 The second main pipe portion and at least a portion thereof are located inside the first pipe and have an inner diameter of D 22 The second thin diameter portion is formed of copper or copper alloy, and has an inner diameter D 12 is the inner diameter D 11 Below, inner diameter D 22 Specific inner diameter D 21 Small, inner diameter D11 / Inner diameter D 12 The value is greater than the inner diameter D 21 / Inner diameter D 22 The value of is small.

[0013] The air conditioner of the present invention comprises: a heat transfer pipe constituting at least a portion of a refrigerant flow path of an indoor heat exchanger and formed of aluminum or an aluminum alloy; and an upstream connecting pipe located upstream of the refrigerant flow relative to the heat transfer pipe during cooling operation, the upstream connecting pipe comprising: a third pipe having an inner diameter D 31 The third main pipe portion and at least a portion of the third main pipe portion are located inside the heat pipe and have an inner diameter of D 32 A third thin-diameter portion formed of aluminum or an aluminum alloy; and a fourth pipe having an inner diameter of D 41 The fourth main pipe portion and at least a portion thereof are located inside the third pipe and have an inner diameter of D 42 The fourth thin diameter portion is formed of copper or copper alloy, and the inner diameter D 32 is the inner diameter D 31 Below, inner diameter D 42 Specific inner diameter D 41 Small, inner diameter D 31 / Inner diameter D 32 The value is greater than the inner diameter D 41 / Inner diameter D 42 The value of is small.

[0014] Effects of the Invention

[0015] According to the present invention, it is possible to suppress the occurrence of refrigerant noise in the indoor unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a diagram for explaining the structure of an air conditioner according to an embodiment of the present invention.

[0017] Figure 2 This is a partially enlarged cross-sectional view schematically showing a connection portion 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.

[0018] Figure 3 This is a partially enlarged cross-sectional view schematically showing a connection portion 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.

[0019] Figure 4 It is a partially enlarged cross-sectional view schematically showing connecting pipes in an air conditioner according to another embodiment of the present invention.

[0020] Figure 5 It is schematically represented Figure 2 A partially enlarged cross-sectional view of a modified example of the downstream connecting pipe shown.

[0021] Figure 6 It is schematically represented Figure 3 A partially enlarged cross-sectional view of a modified example of the upstream connecting pipe shown.

[0022] Figure 7 This is a partially enlarged cross-sectional view schematically showing another connection method between the heat transfer pipe and the connecting pipe of the indoor heat exchanger. DETAILED DESCRIPTION

[0023] Hereinafter, the mode (embodiment) for implementing the air conditioner of the present invention will be described in detail with reference to the accompanying drawings as appropriate. First, the overall structure of the air conditioner will be described, and then the piping in the indoor unit will be described in further detail.

[0024] <Air Conditioner>

[0025] Figure 1 It is a structural diagram of the air conditioner 100 according to this embodiment.

[0026] In addition, Figure 1 In FIG. 1 , the flow of the refrigerant in the heating cycle is indicated by solid arrows, and the flow of the refrigerant in the refrigeration cycle is indicated by dotted arrows.

[0027] like Figure 1 As shown, the air conditioner 100 includes an outdoor unit 101 installed outdoors and an indoor unit 102 installed indoors.

[0028] During cooling operation, the air conditioner 100 receives liquid from the outdoor unit 101 via a liquid pipe 20 having an expansion valve 6 extending midway, and then enters the heat transfer pipe 22 (see FIG. 1 ) of the indoor heat exchanger 4 in the indoor unit 102. Figure 2 ) flows through the indoor heat exchanger 4. At this time, the indoor heat exchanger 4 functions as an evaporator, thereby cooling the surrounding air. The gas refrigerant vaporized in the indoor heat exchanger 4 is then delivered to the outdoor unit 101 via the gas piping 30.

[0029] The gas refrigerant sent to the outdoor unit 101 becomes liquid refrigerant (including gas-liquid two-phase refrigerant) through the compressor 7 of the outdoor unit 101 and the outdoor heat exchanger 3 functioning as a condenser. The liquid refrigerant is sent to the indoor unit 102 again through the liquid pipe 20 .

[0030] In addition, Figure 1 In the figure, reference numeral 9 denotes an outdoor fan that draws outdoor air into the outdoor unit 101 and discharges the outdoor air, which has undergone heat exchange in the outdoor heat exchanger 3 , to the outside of the outdoor unit 101 .

[0031] During heating operation, the air conditioner 100 switches the refrigerant flow path via the four-way valve 8 of the outdoor unit 101, delivering high-temperature, high-pressure gas refrigerant from the compressor 7 to the indoor unit 102 via the gas piping 30. At this time, the indoor heat exchanger 4 functions as a condenser, heating the surrounding air. Furthermore, the liquid refrigerant (including a gas-liquid two-phase refrigerant) condensed within the heat transfer tube (not shown) of the indoor heat exchanger 4 is delivered to the outdoor unit 101 via the liquid piping 20. The liquid refrigerant delivered to the outdoor unit 101 is converted back into high-temperature, high-pressure gas refrigerant via the outdoor heat exchanger 3, which functions as the outdoor unit 101's evaporator, and the compressor 7, and is then delivered to the indoor unit 102.

[0032] The liquid piping 20 includes a liquid piping 20b made of copper or a copper alloy, and liquid piping 20a made of aluminum or an aluminum alloy disposed at both ends of the liquid piping 20b. Furthermore, the gas piping 30 includes a gas piping 30b made of copper or a copper alloy, and gas piping 30a made of aluminum or an aluminum alloy disposed at both ends of the gas piping 30b.

[0033] <Indoor Unit>

[0034] Next, the indoor unit 102 (see Figure 1 ) for explanation.

[0035] like Figure 1 As shown, 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 surface and the upper surface of the cross-flow fan 2 serving as the blower.

[0036] The driven crossflow fan 2 causes indoor air, drawn in through an intake port (not shown) formed in the upper portion of the housing 1 of the indoor unit 102, to pass through the indoor heat exchanger 4 and be blown into the room from the outlet 5 of the housing 1. At this time, the indoor air is cooled or heated, respectively, depending on the cooling or heating operation of the indoor heat exchanger 4. The indoor unit 102 blows out this conditioned air from the outlet 5.

[0037] Figure 2 : is a partially enlarged cross-sectional view schematically showing the connection portion between the indoor heat exchanger 4 and the gas pipe 30. Figure 2 In FIG. 1 , the outline arrows denoted by the symbol R indicate the flow direction of the refrigerant during cooling operation.

[0038] like Figure 2 As shown, the indoor heat exchanger 4 includes plate-shaped fins 21 and heat transfer pipes 22 .

[0039] A plurality of plate-shaped fins 21 are stacked at predetermined intervals in the plate thickness direction. The fins 21 in this embodiment are formed of aluminum or an aluminum alloy.

[0040] like Figure 2 As shown in FIG. 1 , the heat transfer pipe 22 is formed so as to penetrate the plurality of fins 21 in the stacking direction. The heat transfer pipe 22 in this embodiment is formed of aluminum or an aluminum alloy.

[0041] like Figure 2 As shown, the gas pipe 30 is a pipe through which the refrigerant R flowing out of the heat transfer pipe 22 during cooling operation passes. The gas pipe 30 corresponds to a downstream connecting pipe located downstream of the heat transfer pipe 22 in the direction in which the refrigerant R flows.

[0042] As described above, the gas pipe 30 includes the gas pipe 30 a made of aluminum or an aluminum alloy, and the gas pipe 30 b made of copper or a copper alloy.

[0043] One end portion of the base tube of the gas pipe 30 a is partially reduced in diameter, and the outer surface of the gas pipe 30 a is fitted so as to come into contact with the inner surface of the heat transfer tube 22 .

[0044] Specifically, the gas pipe 30a has an inner diameter D 11 The first main pipe portion 30a1 and the inner diameter D 11 Reduced inner diameter D 12 The first thin-diameter portion 30a2.

[0045] The gas pipe 30a corresponds to the "first pipe".

[0046] In addition, the diameter of the first main pipe portion 30a1 may also be larger than the diameter of the tube blank.

[0047] In addition, in this embodiment, the first main pipe portion 30a1 is assumed to have an inner diameter D 11 The circular tube is constant in the extending direction of the pipe, but the present invention does not exclude the tube having an inner diameter D 11 The gas pipe 30a of the first main pipe portion 30a1 slightly changes in the pipe extending direction.

[0048] The inner diameter D of the first main pipe portion 30a1 is 11 The inner diameter D is the value measured at the position closest to the first small diameter portion 30a2. 11 It is the inner diameter of the end portion of the first main pipe portion 30a1 on the first small diameter portion 30a2 side.

[0049] In addition, in this embodiment, the first small diameter portion 30a2 is assumed to have an inner diameter D 12 The circular tube is constant in the extending direction of the pipe, but the present invention does not exclude the tube having an inner diameter D 12 The gas pipe 30a has a first small diameter portion 30a2 that slightly changes in the pipe extending direction.

[0050] The inner diameter D of the first small diameter portion 30a2 is12 The inner diameter D varies in the extending direction of the first thin-diameter portion 30a2. 12 The minimum value in is determined.

[0051] like Figure 2 As shown, one end portion of the tube of the gas pipe 30b is partially reduced in diameter, and the outer surface of the gas pipe 30b is fitted so as to contact the inner surface of the gas pipe 30a (first main pipe portion 30a1).

[0052] Specifically, the gas pipe 30b has an inner diameter D 21 The second main pipe portion 30b1 and the inner diameter D 21 Reduced inner diameter D 22 The second thin-diameter portion 30b2.

[0053] The gas pipe 30b corresponds to the "second pipe".

[0054] Furthermore, the second main pipe portion 30b1 may have a larger diameter than the base pipe.

[0055] In addition, in this embodiment, the second main pipe portion 30b1 is assumed to have an inner diameter D 21 The circular tube is constant in the extending direction of the pipe, but the present invention does not exclude the tube having an inner diameter D 21 The gas pipe 30b has a second main pipe portion 30b1 that slightly changes in the pipe extending direction.

[0056] The inner diameter D of the second main pipe portion 30b1 is 21 The inner diameter D is the value measured at the position closest to the second small diameter portion 30b2. 21 It is the inner diameter of the end portion of the second main pipe portion 30b1 on the second small diameter portion 30b2 side.

[0057] In addition, in this embodiment, the second small diameter portion 30b2 is assumed to have an inner diameter D 22 The circular tube is constant in the extending direction of the pipe, but the present invention does not exclude the tube having an inner diameter D 22 The gas pipe 30b has a second small diameter portion 30b2 that slightly changes in the pipe extending direction.

[0058] The inner diameter D of the second narrow portion 30b2 is 22 The inner diameter D varies in the extending direction of the second thin-diameter portion 30b2. 22 The minimum value in is determined.

[0059] In the gas pipe 30 (downstream connecting pipe) as described above, the inner diameter D of the first main pipe portion 30a1 in the gas pipe 30a (first pipe) is 11 Divide by the inner diameter D of the first thin-diameter portion 30a2 12 The obtained value (inner diameter D11 / Inner diameter D 12 The value of ) is greater than the inner diameter D of the second main pipe portion 30b1 in the gas pipe 30b (second pipe). 21 Divide by the inner diameter D of the second thin-diameter portion 30b2 22 The obtained value (inner diameter D 21 / Inner diameter D 22 That is, the gas pipe 30a (first pipe) and the gas pipe 30b (second pipe) satisfy the inner diameter D 11 / Inner diameter D 12 <Inner diameter D 21 / Inner diameter D 22 The relationship formula.

[0060] In the gas pipe 30 (downstream connecting pipe), the inner diameter D of the first main pipe portion 30a1 in the gas pipe 30a (first pipe) is 11 Divide by the inner diameter D of the second narrow portion 30b2 of the gas pipe 30b (second pipe) 22 The value of inner diameter D 11 / Inner diameter D 22 The value of ) is greater than the inner diameter D of the second main pipe portion 30b1 in the gas pipe 30b (second pipe). 21 Divide by the inner diameter D of the second thin-diameter portion 30b2 22 The value of inner diameter D 21 / Inner diameter D 22 That is, the gas pipe 30a (first pipe) and the gas pipe 30b (second pipe) satisfy the inner diameter D 11 / Inner diameter D 22 <Inner diameter D 21 / Inner diameter D 22 The relationship formula.

[0061] In the gas pipe 30 (downstream connecting pipe), the wall thickness T of the second main pipe portion 30b1 in the gas pipe 30b (second pipe) is 21 is the wall thickness T of the first main pipe portion 30a1 in the gas pipe 30a (first pipe). 11 More than 1 / 3 of the total.

[0062] Next, the liquid piping 20 in this embodiment (see Figure 1 ) for more detailed explanation.

[0063] Figure 3 The indoor heat exchanger 4 is schematically shown (see Figure 1 ) and liquid piping 20 (refer to Figure 1 ) is a partially enlarged cross-sectional view of the connection portion. Figure 3 In FIG. 1 , the outline arrows denoted by the symbol R indicate the flow direction of the refrigerant during cooling operation.

[0064] like Figure 3 As shown, the liquid pipe 20 is a pipe through which the refrigerant R flowing into the heat transfer pipe 22 during cooling operation passes. The liquid pipe 20 corresponds to an upstream connecting pipe located upstream of the heat transfer pipe 22 in the direction in which the refrigerant R flows.

[0065] As described above, the liquid pipe 20 includes the liquid pipe 20 a made of aluminum or an aluminum alloy, and the liquid pipe 20 b made of copper or a copper alloy.

[0066] One end portion of the base tube of the liquid pipe 20 a is partially reduced in diameter, and the outer surface of the liquid pipe 20 a is fitted so as to come into contact with the inner surface of the heat transfer pipe 22 .

[0067] Specifically, the liquid pipe 20a has an inner diameter D 31 The third main pipe portion 20a1 and the inner diameter D 31 Reduced inner diameter D 32 The third thin-diameter portion 20a2.

[0068] The liquid pipe 20a corresponds to the "third pipe".

[0069] In addition, the diameter of the third main pipe portion 20a1 may be larger than the diameter of the base pipe.

[0070] In addition, the third main pipe portion 20a1 in this embodiment is assumed to have an inner diameter D 31 The circular tube is constant in the extending direction of the pipe, but the present invention does not exclude the tube having an inner diameter D 31 The liquid pipe 20a of the third main pipe portion 20a1 slightly changes in the pipe extending direction.

[0071] The inner diameter D of the third main pipe portion 20a1 is 31 The inner diameter D is the value measured at the position closest to the third thin-diameter portion 20a2. 31 It is the inner diameter of the end portion of the third main pipe portion 20a1 on the third small diameter portion 20a2 side.

[0072] In addition, the third small diameter portion 20a2 in this embodiment is assumed to have an inner diameter D 32 The circular tube is constant in the extending direction of the pipe, but the present invention does not exclude the tube having an inner diameter D 32 The liquid pipe 20a has a third narrow portion 20a2 that slightly changes in the pipe extending direction.

[0073] The inner diameter D of the third narrow portion 20a2 is 32 The inner diameter D varies in the extending direction of the third thin-diameter portion 20a2. 32 Determine the minimum value in .

[0074] like Figure 3 As shown, one end portion of the tube of the liquid pipe 20b is partially reduced in diameter, and the outer surface of the liquid pipe 20b is fitted so as to contact the inner surface of the liquid pipe 20a (third main pipe portion 20a1).

[0075] Specifically, the liquid pipe 20b has an inner diameter D 41 The fourth main pipe portion 20b1 and the inner diameter D 41 Reduced inner diameter D 42 The fourth thin-diameter portion 20b2.

[0076] The liquid pipe 20b corresponds to the "fourth pipe".

[0077] Furthermore, the fourth main pipe portion 20b1 may have a larger diameter than the base pipe.

[0078] In addition, the fourth main pipe portion 20b1 in this embodiment is assumed to have an inner diameter D 41 The circular tube is constant in the extending direction of the pipe, but the present invention does not exclude the tube having an inner diameter D 41 The liquid pipe 20b of the fourth main pipe portion 20b1 slightly changes in the pipe extending direction.

[0079] The inner diameter D of the fourth main pipe portion 20b1 is 41 The inner diameter D is the value measured at the position closest to the fourth thin-diameter portion 20b2. 41 It is the inner diameter of the end portion of the fourth main pipe portion 20b1 on the fourth small-diameter portion 20b2 side.

[0080] In addition, the fourth small diameter portion 20b2 in this embodiment is assumed to have an inner diameter D 42 The circular tube is constant in the extending direction of the pipe, but the present invention does not exclude the tube having an inner diameter D 42 The liquid pipe 20b has a fourth narrow portion 20b2 that slightly changes in the pipe extending direction.

[0081] The inner diameter D of the fourth thin-diameter portion 20b2 is 42 The inner diameter D varies in the extending direction of the fourth thin-diameter portion 20b2. 22 Determine the minimum value in .

[0082] In the liquid pipe 20 (upstream connecting pipe) as described above, the inner diameter D of the third main pipe portion 20a1 in the liquid pipe 20a (third pipe) is 31 Divide by the inner diameter D of the third thin-diameter portion 20a2 32 The obtained value (inner diameter D 31 / Inner diameter D 32 The value of ) is greater than the inner diameter D of the fourth main pipe portion 20b1 in the liquid pipe 20b (fourth pipe). 41Divide by the inner diameter D of the fourth thin-diameter portion 20b2 42 The obtained value (inner diameter D 41 / Inner diameter D 42 That is, the liquid pipe 20a (third pipe) and the liquid pipe 20b (fourth pipe) satisfy the inner diameter D 31 / Inner diameter D 32 <Inner diameter D 41 / Inner diameter D 42 The relationship formula.

[0083] In addition, in the liquid pipe 20 (upstream connecting pipe), the inner diameter D of the third main pipe portion 20a1 in the liquid pipe 20a (third pipe) is 31 Divide by the inner diameter D of the fourth narrow portion 20b2 of the liquid pipe 20b (fourth pipe) 42 The obtained value (inner diameter D 31 / Inner diameter D 42 The value of ) is greater than the inner diameter D of the fourth main pipe portion 20b1 in the liquid pipe 20b (fourth pipe). 41 Divide by the inner diameter D of the fourth thin-diameter portion 20b2 42 The obtained value (inner diameter D 41 / Inner diameter D 42 That is, the liquid pipe 20a (third pipe) and the liquid pipe 20b (fourth pipe) satisfy the inner diameter D 31 / Inner diameter D 42 <Inner diameter D 41 / Inner diameter D 42 The relationship formula.

[0084] In addition, in the liquid pipe 20 (upstream connecting pipe), the wall thickness T of the fourth main pipe portion 20b1 in the liquid pipe 20b (fourth pipe) is 41 is the wall thickness T of the third main pipe portion 20a1 in the liquid pipe 20a (third pipe). 31 More than 1 / 3 of the total.

[0085] <Effects>

[0086] Next, the effects achieved by the air conditioner 100 according to this embodiment will be described.

[0087] As mentioned above, using aluminum tubes in indoor units increases the refrigerant noise generated by the flowing refrigerant. Typically, the joint in dissimilar-material jointed tubes, such as aluminum and copper tubes, is achieved by inserting one tube inside the other. Consequently, the cross-sectional area of ​​one tube in such a jointed tube varies from the cross-sectional area of ​​the other tube.

[0088] When such a change in the cross-sectional area occurs in the joined pipe, so-called refrigerant noise is generated due to energy loss of the refrigerant flowing inside the joined pipe.

[0089] The present inventors have achieved the air conditioner 100 of this embodiment based on the finding that pipes made of aluminum, which has a lower density than copper, are more likely to make refrigerant noise than copper pipes.

[0090] The air conditioner 100 of this embodiment includes: a heat transfer pipe 22, which constitutes at least a portion of the flow path of the refrigerant R in the indoor heat exchanger 4 and is formed of aluminum or an aluminum alloy; and a gas piping 30 (downstream connecting piping) which is located downstream of the flow of the refrigerant R relative to the heat transfer pipe 22 during cooling operation. The gas piping 30 (downstream connecting piping) includes: a gas piping 30a (first piping) having an inner diameter D 11 The first main pipe portion 30a1 and at least a portion thereof are located inside the heat pipe 22 and have an inner diameter of D 12 The first small diameter portion 30a2 is formed of aluminum or an aluminum alloy; and a gas pipe 30b (second pipe) having an inner diameter of D 21 The second main pipe section 30b1 and at least a portion thereof are located inside the gas pipe 30a (first pipe) and have an inner diameter of D 22 The second thin-diameter portion 30b2 is formed of copper or copper alloy, and has an inner diameter D 12 is the inner diameter D 11 Below, inner diameter D 22 Specific inner diameter D 21 Small, and inner diameter D 11 / Inner diameter D 12 The value is greater than the inner diameter D 21 / Inner diameter D 22 For convenience, the term "small diameter portion" is used, but the inner diameter D of the first small diameter portion 30a2 is 12 It may also be the same as the inner diameter D of the first main pipe portion 30a1. 11 In this case, the gas pipe 30 located inside the heat pipe 22 is the first small diameter portion 30a2, and the gas pipe 30 not located inside the heat pipe 22 is the first main pipe portion 30a1. On the other hand, in this embodiment, the inner diameter D excluding the second small diameter portion 30b2 is 22 The inner diameter D of the second main pipe portion 30b1 is 21 For the same value.

[0091] According to the air conditioner 100, the change in the cross-sectional area of ​​the gas pipe 30a (first pipe) formed of aluminum or an aluminum alloy, which is prone to refrigerant noise, is reduced compared to the change in the cross-sectional area of ​​the gas pipe 30b (second pipe) formed of copper or a copper alloy. This can suppress the generation of refrigerant noise in the indoor unit 102. Specifically, the generation of refrigerant noise in the gas pipe 30 (downstream connecting pipe) located downstream of the flow of the refrigerant R relative to the indoor heat exchanger 4 can be suppressed.

[0092] Furthermore, in the gas pipe 30a (first pipe) of the air conditioner 100, energy loss occurs in the circulating refrigerant not only when the cross-sectional area increases from the connection side with the heat transfer pipe 22 toward the first main pipe portion 30a1, but also when the cross-sectional area decreases. This energy loss also generates refrigerant noise.

[0093] The inner diameter D of the air conditioner 100 of this embodiment 11 / Inner diameter D 22 The value is greater than the inner diameter D 21 / Inner diameter D 22 The value of is small.

[0094] According to the air conditioner 100 , it is possible to more reliably suppress the occurrence of refrigerant noise in the gas pipe 30 (downstream connecting pipe).

[0095] The air conditioner 100 of this embodiment includes: a heat transfer pipe 22, which constitutes at least a portion of the flow path of the refrigerant R of the indoor heat exchanger 4 and is formed of aluminum or an aluminum alloy; and a liquid piping 20 (upstream connecting piping) which is located upstream of the flow of the refrigerant R relative to the heat transfer pipe 22 during cooling operation. The liquid piping 20 (upstream connecting piping) includes: a liquid piping 20a (third piping) having an inner diameter D 31 The third main pipe portion 20a1 and at least a portion thereof are located inside the heat pipe 22 and have an inner diameter of D 32 The third thin-diameter portion 20a2 is formed of aluminum or an aluminum alloy; and a liquid piping 20b (fourth piping) having an inner diameter of D 41 The fourth main pipe portion 20b1 and at least a portion thereof are located inside the liquid pipe 20a (third pipe) and have an inner diameter of D 42 The fourth thin-diameter portion 20b2 is formed of copper or copper alloy, and has an inner diameter D 32 is the inner diameter D 31 Below, inner diameter D 42 Specific inner diameter D 41 Small, and inner diameter D 31 / Inner diameter D 32 The value is greater than the inner diameter D 41 / Inner diameter D 42For convenience, the term "small diameter portion" is used, but the inner diameter D of the third small diameter portion 20a2 is 32 It can also be the same as the inner diameter D of the third main pipe part 20a1. 31 In this case, the liquid pipe 20 located inside the heat pipe 22 is the third small diameter portion 20a2, and the liquid pipe 20 not located inside the heat pipe 22 is the third main pipe portion 20a1. On the other hand, in this embodiment, the inner diameter D excluding the fourth small diameter portion 20b2 is 42 The inner diameter D of the fourth main pipe portion 20b1 is 41 For the same value.

[0096] According to the air conditioner 100 , the generation of refrigerant noise in the liquid pipe 20 (upstream connecting pipe) located upstream of the flow of the refrigerant R with respect to the indoor heat exchanger 4 can be suppressed.

[0097] In addition, the inner diameter D of the air conditioner 100 is 31 / Inner diameter D 42 The value is greater than the inner diameter D 41 / Inner diameter D 42 The value of is small.

[0098] According to the air conditioner 100 , the generation of refrigerant noise in the liquid pipe 20 (upstream connecting pipe) can be more reliably suppressed.

[0099] In the air conditioner 100 of the present embodiment, the surface density [density×pipe wall thickness] of the second main pipe portion 30b1 is greater than the surface density [density×pipe wall thickness] of the first main pipe portion 30a1.

[0100] According to the air conditioner 100, if the surface density of the gas pipe 30b (second pipe) formed of copper or a copper alloy is greater than the surface density of the gas pipe 30a (first pipe) formed of aluminum or an aluminum alloy, refrigerant noise in the gas pipe 30a (first pipe) is more likely to be heard. Furthermore, the density of aluminum is approximately one-third of that of copper.

[0101] In the air conditioner 100 of this embodiment, the wall thickness T of the second main pipe portion 30b1 in the gas pipe 30b (second pipe) is 21 is the wall thickness T of the first main pipe portion 30a1 in the gas pipe 30a (first pipe). 11 More than 1 / 3 of the total.

[0102] According to the air conditioner 100 , the generation of refrigerant noise in the gas pipe 30 (downstream connecting pipe) can be more reliably suppressed.

[0103] In the air conditioner 100 of the present 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.

[0104] In this air conditioner 100, if the surface density [density x pipe wall thickness] of the liquid pipe 20b (fourth pipe) formed of copper or a copper alloy is greater than that of the liquid pipe 20a (third pipe) formed of aluminum or an aluminum alloy, refrigerant noise in the liquid pipe 20a (third pipe) is more likely to be heard. Furthermore, the density of aluminum is approximately one-third of that of copper.

[0105] In the air conditioner 100, the wall thickness T of the fourth main pipe portion 20b1 in the liquid pipe 20b (fourth pipe) is 41 is the wall thickness T of the third main pipe portion 20a1 in the liquid pipe 20a (third pipe). 31 More than 1 / 3 of the total.

[0106] According to the air conditioner 100 , the generation of refrigerant noise in the liquid pipe 20 (upstream connecting pipe) can be more reliably suppressed.

[0107] In the air conditioner 100, the inner diameter D of the first main pipe portion 30a1 is 11 than the inner diameter D of the second main pipe portion 30b1 21 The inner diameter D of the second main pipe portion 30b1 is small. 21 It is smaller than the inner diameter of the heat transfer pipe 22 .

[0108] According to the air conditioner 100, the inner diameter of the gas pipe 30a (first pipe) disposed between the heat pipe 22 and the gas pipe 30b (second pipe) is set to be between the inner diameter of the heat pipe 22 and the inner diameter of the gas pipe 30b (second pipe), and the inner diameter gradually changes. As a result, it is believed that the pressure loss of the air conditioner 100 is small. However, in reality, the refrigerant noise increases due to the increased pipe contraction rate of the gas pipe 30a (first pipe). Therefore, by intentionally reducing the inner diameter D of the first main pipe portion 30a1, the refrigerant noise is increased. 11 , suppressing the shrinkage rate of the gas piping 30a (first piping).

[0109] In the air conditioner 100, the inner diameter D of the third main pipe portion 20a1 is 31 than the inner diameter D of the fourth main pipe portion 20b1 41 The inner diameter D of the fourth main pipe portion 20b1 is small. 41 It is smaller than the inner diameter of the heat transfer pipe 22 .

[0110] According to the air conditioner 100, the inner diameter of the liquid pipe 20a (third pipe) disposed between the heat transfer pipe 22 and the liquid pipe 20b (fourth pipe) is set to be between the inner diameter of the heat transfer pipe 22 and the inner diameter of the liquid pipe 20b (fourth pipe), and the inner diameter gradually changes. As a result, it is believed that the pressure loss of the air conditioner 100 is small. However, in reality, the refrigerant noise increases due to the increased pipe contraction rate of the liquid pipe 20a (third pipe). Therefore, by intentionally reducing the inner diameter D of the third main pipe portion 20a1, the refrigerant noise is increased. 31 , suppressing the tube shrinkage rate of the liquid piping 20a (third piping).

[0111] In the air conditioner 100, the inner diameter D of the first narrow portion 30a2 is 12 than the inner diameter D of the second thin-diameter portion 30b2 22 big.

[0112] According to the air conditioner 100, in addition to the tube reduction rate of the first small diameter portion 30a2 in the gas pipe 30a (first pipe), the inner diameter D of the first small diameter portion 30a2 is increased. 12 The value itself can suppress the generation of refrigerant noise.

[0113] In the air conditioner 100, the inner diameter D of the third narrow portion 20a2 is 32 than the inner diameter D of the fourth thin-diameter portion 20b2 42 big.

[0114] According to the air conditioner 100, in addition to the tube reduction rate of the third narrow portion 20a2 in the liquid pipe 20a (third pipe), the inner diameter D of the third narrow portion 20a2 is increased. 32 The value itself can suppress the generation of refrigerant noise.

[0115] In addition, in such an air conditioner 100, the inner diameter D 11 The inner diameter D is the inner diameter of the end portion of the first main pipe portion 30a1 on the first small diameter portion 30a2 side. 12 The inner diameter D is the smallest inner diameter portion of the first narrow diameter portion 30a2. 21 The inner diameter D is the inner diameter of the end portion of the second main pipe portion 30b1 on the second small diameter portion 30b2 side. 22 It is the inner diameter of the portion with the smallest inner diameter in the second narrow-diameter portion 30b2.

[0116] According to the air conditioner 100 , the occurrence of refrigerant noise can be more reliably suppressed.

[0117] In addition, in this air conditioner 100, the inner diameter D 31 The inner diameter D is the inner diameter of the end portion of the third main pipe portion 20a1 on the third small diameter portion 20a2 side. 32The inner diameter D is the smallest inner diameter portion of the third narrow-diameter portion 20a2. 41 The inner diameter D is the inner diameter of the end portion of the fourth main pipe portion 20b1 on the fourth thin-diameter portion 20b2 side. 42 It is the inner diameter of the portion with the smallest inner diameter in the fourth narrow-diameter portion 20b2.

[0118] According to the air conditioner 100 , the occurrence of refrigerant noise can be more reliably suppressed.

[0119] As mentioned above, although embodiment of this invention was described, this invention is not limited to this embodiment, and can be implemented in various forms.

[0120] In the embodiment, Figure 2 As shown in FIG. 1 , it is assumed that the inner diameter D of the first narrow portion 30a2 of the gas pipe 30 (downstream connecting pipe) is 12 The inner diameter D of the second narrow diameter portion 30b2 is constant in the longitudinal direction of the pipe portion. 22 , is also assumed to be constant in the length direction.

[0121] However, at least one of the first small diameter portion 30a2 and the second small diameter portion 30b2 may be formed in a tapered shape.

[0122] In the above embodiment, the inner diameter D of the first small diameter portion 30a2 is configured to be 12 is the inner diameter D of the first main pipe portion 30a1 11 However, the inner diameter D of the first small diameter portion 30a2 may be configured as follows: 12 than the inner diameter D of the first main pipe portion 30a1 11 Small.

[0123] In the above embodiment, the inner diameter D of the third small diameter portion 20a2 is configured to be 32 is the inner diameter D of the third main pipe portion 20a1 11 However, the inner diameter D of the third small diameter portion 20a2 may be configured as follows: 32 smaller than the inner diameter D of the third main pipe portion 20a1 31 .

[0124] Figure 4 It is a partially enlarged cross-sectional view schematically showing a connecting pipe structure in another embodiment. Figure 4 1 and 2. The diagram shows a state where the diameter-reduced portion Pb2 of the second pipe Pb is fitted inside the base pipe portion Pa1 of the first pipe Pa.

[0125] 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 toward the front end.

[0126] Figure 4 The second pipe Pb corresponds to Figure 2 The gas pipe 30a (first pipe) shown is a first main pipe portion 30a1. Figure 4 The first pipe Pa and Figure 2 The heat pipe 22 shown corresponds to .

[0127] and, Figure 2 The inner diameter D of the first thin-diameter portion 30a2 is shown as 12 Corresponding to Figure 4 The front end portion D2 with the smallest inner diameter in the tapered reduced diameter portion Pb2 shown, Figure 2 The inner diameter D of the first main pipe portion 30a1 is shown as 11 Corresponding to Figure 4 The inner diameter D1 of the tube portion Pb1 closest to the tapered reduced diameter portion Pb2 is shown.

[0128] in addition, Figure 4 The second pipe Pb corresponds to Figure 2 The second main pipe portion 30b1 of the gas pipe 30b (second pipe) is shown. Figure 4 The first pipe Pa corresponds to Figure 2 The gas pipe 30a (first pipe) shown is a first main pipe portion 30a1.

[0129] and, Figure 2 The inner diameter D of the second thin-diameter portion 30b2 is shown as 22 Corresponding to Figure 4 The front end portion D2 with the smallest inner diameter in the tapered reduced diameter portion Pb2 shown, Figure 2 The inner diameter D of the second main pipe portion 30b1 is shown as 21 Corresponding to Figure 4 The inner diameter D1 of the tube portion Pb1 closest to the tapered reduced diameter portion Pb2 is shown.

[0130] in addition, Figure 4 The tapered connecting pipe structure shown can also be applied to Figure 3 The liquid piping 20 (upstream side connecting piping) is shown.

[0131] Right now, Figure 4 The second pipe Pb corresponds to Figure 3 The third main pipe portion 20a1 of the liquid pipe 20a (third pipe) is shown. Figure 4 The first pipe Pa corresponds to Figure 3 The heat pipe 22 is shown.

[0132] and, Figure 3 The inner diameter D of the third thin-diameter portion 20a2 is shown as 32 Corresponding to Figure 4The front end portion D2 with the smallest inner diameter in the tapered reduced diameter portion Pb2 shown, Figure 3 The inner diameter D of the third main pipe portion 20a1 is shown as 31 Corresponding to Figure 4 The inner diameter D1 of the tube portion Pb1 closest to the tapered reduced diameter portion Pb2 is shown.

[0133] in addition, Figure 4 The second pipe Pb corresponds to Figure 3 The fourth main pipe portion 20b1 of the liquid pipe 20b (fourth pipe) is shown. Figure 4 The first pipe Pa corresponds to Figure 3 The third main pipe portion 20a1 of the liquid pipe 20a (third pipe) is shown.

[0134] and, Figure 2 The inner diameter D of the fourth thin-diameter portion 20b2 is shown as 42 Corresponding to Figure 4 The front end portion D2 with the smallest inner diameter in the tapered reduced diameter portion Pb2 shown, Figure 3 The inner diameter D of the fourth main pipe portion 20b1 is shown as 41 Corresponding to Figure 4 The inner diameter D1 of the tube portion Pb1 closest to the tapered reduced diameter portion Pb2 is shown.

[0135] In addition, in the above-described embodiment, in the joint structure between the heat transfer pipe 22 and the gas pipe 30 (downstream connecting pipe), as shown in FIG. Figure 2 As shown, assuming the inner diameter D 11 / Inner diameter D 12 The value exceeds 1 (inner diameter D 11 / Inner diameter D 12 >1), but the present invention does not exclude the inner diameter D 11 With inner diameter D 12 Equal case (inner diameter D 11 / Inner diameter D 12 =1).

[0136] In addition, in the joint structure between the heat transfer pipe 22 and the liquid pipe 20 (downstream connecting pipe), as shown in FIG. Figure 3 As shown, it is also assumed that the inner diameter D 31 / Inner diameter D 32 The value exceeds 1 (inner diameter D 31 / Inner diameter D 32 >1), but the present invention does not exclude the inner diameter D 31 With inner diameter D 32 Equal case (inner diameter D 31 / Inner diameter D 32 =1).

[0137] In addition, in the embodiment, Figure 2 as well as Figure 3 As shown, the inlet and outlet of the indoor heat exchanger 4 is composed of one passage, but the inlet and outlet of the indoor heat exchanger can also be composed of multiple passages. Figure 2 The gas piping 30a (first piping) shown is connected to Figure 3 The liquid pipe 20a (third pipe) shown has a pipe structure of a converging / branching pipe.

[0138] Figure 5 The gas pipe 30a (see FIG. Figure 2 ) is a partially enlarged cross-sectional view of a modified example. Figure 5 In the figure, reference numeral 21 denotes a fin of the indoor heat exchanger 4, reference numeral 22 denotes a heat transfer pipe made of aluminum or an aluminum alloy, and reference numeral R denotes a refrigerant.

[0139] like Figure 5 As shown, the gas piping 30a (first piping) according to the modified example includes a first main pipe section 30a1 serving as the outlet pipes for two passages from the indoor heat exchanger 4, and a first main pipe section 30a1 serving as a converging pipe where these outlet pipes merge. Furthermore, the first main pipe section 30a1, serving as the outlet pipes for the two passages, is connected to the heat transfer pipe 22 of the indoor heat exchanger 4 via a first narrow-diameter section 30a2. Specifically, at least a portion of the first narrow-diameter section 30a2 is located inside the heat transfer pipe 22.

[0140] Such a gas pipe 30a (first pipe) is formed of aluminum or an aluminum alloy.

[0141] The gas pipe 30b (second pipe) is formed of copper or a copper alloy and includes a second main pipe portion 30b1 and a second small diameter portion 30b2 at least partially located inside the first main pipe portion 30a1 which is a converging pipe.

[0142] And, as Figure 5 As shown, the inner diameter D of the first main pipe portion 30a1 is 11 The inner diameter D of the first small diameter portion 30a2 is determined by the inner diameter of the end portion of the outlet pipe, namely the first main pipe portion 30a1, which is located on the first small diameter portion 30a2 side. 12 The inner diameter D of the second main pipe section 30b1 is determined by the inner diameter of the smallest portion of the first small diameter section 30a2. 21 The inner diameter D of the second small diameter portion 30b2 is determined by the inner diameter of the end portion of the second main pipe portion 30b1 on the second small diameter portion 30b2 side. 22 It is determined by the inner diameter of the portion with the smallest inner diameter in the second narrow-diameter portion 30b2.

[0143] And, the inner diameter D 12 is the inner diameter D 11 Below, inner diameter D22 Specific inner diameter D 21 Small, and inner diameter D 11 / Inner diameter D 12 The value is greater than the inner diameter D 21 / Inner diameter D 22 In addition, the inner diameter D 11 Specific inner diameter D 21 Small, and inner diameter D 21 Smaller than the inner diameter of the heat pipe. In addition, the inner diameter D 12 Specific inner diameter D 22 big.

[0144] According to such a modification, it is possible to diversify the downstream connecting pipe structure that suppresses the generation of refrigerant noise.

[0145] Figure 6 The figure schematically shows the liquid pipe 20a (see FIG. Figure 3 ) is a partially enlarged cross-sectional view of a modified example. Figure 6 In the figure, reference numeral 21 denotes a fin of the indoor heat exchanger 4, reference numeral 22 denotes a heat transfer pipe made of aluminum or an aluminum alloy, and reference numeral R denotes a refrigerant.

[0146] like Figure 6 As shown, the liquid piping 20a (third piping) according to the modified example includes a third main pipe section 20a1 serving as the inlet pipes (branch pipes) for two passages leading to the indoor heat exchanger 4, and a third main pipe section 20a1 serving as a branching source from these inlet pipes. Furthermore, the third main pipe section 20a1, serving as the inlet pipes for the two passages, is connected to the heat transfer pipe 22 of the indoor heat exchanger 4 via a third narrow-diameter portion 20a2. Specifically, at least a portion of the third narrow-diameter portion 20a2 is located inside the heat transfer pipe 22.

[0147] Such liquid pipe 20a (third pipe) is formed of aluminum or an aluminum alloy.

[0148] The liquid pipe 20b (fourth pipe) is formed of copper or a copper alloy and includes a fourth main pipe portion 20b1 and a fourth narrow-diameter portion 20b2 at least partially located inside the third main pipe portion 20a1 serving as a branch source.

[0149] And, as Figure 6 As shown, the inner diameter D of the third main pipe portion 20a1 is 31 The inner diameter D of the third small diameter portion 20a2 is determined by the inner diameter of the end portion of the third main pipe 20a1, which is the inlet pipe (branch pipe). 32 The inner diameter D of the fourth main pipe section 20b1 is determined by the inner diameter of the smallest portion of the third small diameter section 20a2. 41The inner diameter D of the fourth main pipe portion 20b1 is determined by the inner diameter of the end portion on the fourth small diameter portion 20b2 side. 42 It is determined by the inner diameter of the portion with the smallest inner diameter in the fourth thin-diameter portion 20b2.

[0150] And, the inner diameter D 32 is the inner diameter D 31 Below, inner diameter D 42 Specific inner diameter D 41 Small, and inner diameter D 31 / Inner diameter D 32 The value is greater than the inner diameter D 41 / Inner diameter D 42 In addition, the inner diameter D 31 Specific inner diameter D 41 Small, and inner diameter D 41 Smaller than the inner diameter of the heat pipe. In addition, the inner diameter D 32 Specific inner diameter D 42 big.

[0151] According to such a modification, it is possible to diversify the upstream connecting pipe structure that suppresses the generation of refrigerant noise.

[0152] in addition, Figure 2 as well as Figure 5 The connection between the heat transfer pipe 22 and the gas pipe 30 a (first pipe) shown is configured such that a portion of the first small diameter portion 30 a 2 is located inside the heat transfer pipe 22 .

[0153] However, in the air conditioner 100 of the present invention, although not shown in the drawings, the first small diameter portion 30 a 2 may be entirely located inside the heat transfer pipe 22 .

[0154] In addition, as shown in FIG. 1 , another connection method between the heat transfer pipe 22 and the gas pipe 30a (first pipe) is shown. Figure 7 As shown, the front end portion of the first main pipe portion 30 a 1 may be positioned inside the heat transfer pipe 22 , thereby positioning the entire first small diameter portion 30 a 2 inside the heat transfer pipe 22 .

[0155] in addition, Figure 3 as well as Figure 6 The connection between the heat transfer pipe 22 and the liquid pipe 20 a (third pipe) shown is configured such that a portion of the third small diameter portion 20 a 2 is located inside the heat transfer pipe 22 .

[0156] However, although not shown in the figure, the air conditioner 100 of the present invention may be configured such that the entire third narrow-diameter portion 20a2 is located inside the heat transfer tube 22. Furthermore, although not shown in the figure, the front end portion of the third main pipe portion 20a1 may be located inside the heat transfer tube 22, thereby allowing the entire third narrow-diameter portion 20a2 to be located inside the heat transfer tube 22.

[0157] Explanation of symbols

[0158] 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 pipe section; 20a2—Third narrow section; 20b1—Fourth main pipe section; 20b2—Fourth narrow section; 21—Fin; 22—Heat transfer pipe; 30—Gas piping (downstream connecting piping); 30a—Gas piping (first piping); 30b—Gas piping (second piping); 30a1—First main pipe section; 30a2—First narrow section; 30b1—Second main pipe section; 30b2—Second narrow section; 100—Air conditioner; 101—Outdoor unit; 102—Indoor unit; R—Refrigerant.

Claims

1. An air conditioner, characterized in that: have: a heat transfer pipe constituting at least a portion of a refrigerant flow path of the indoor heat exchanger and formed of aluminum or an aluminum alloy; and The downstream connecting pipe is located on the downstream side of the refrigerant flow relative to the heat transfer pipe during cooling operation. The downstream connecting pipe includes: The first pipe has an inner diameter D 11 The first main pipe portion and at least a portion thereof are located inside the heat conducting pipe and have an inner diameter of D 12 The first thin-diameter portion is formed of aluminum or an aluminum alloy; as well as The second pipe has an inner diameter D 21 The second main pipe portion and at least a portion thereof are located inside the first pipe and have an inner diameter of D 22 The second thin diameter portion is formed of copper or a copper alloy, Inner diameter D 12 is the inner diameter D 11 Below, inner diameter D 22 Specific inner diameter D 21 Small, inner diameter D 11 / Inner diameter D 12 The value is greater than the inner diameter D 21 / Inner diameter D 22 The value of is small.

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

3. An air conditioner, characterized in that: have: a heat transfer pipe constituting at least a portion of a refrigerant flow path of the indoor heat exchanger and formed of aluminum or an aluminum alloy; and The upstream connecting pipe is located upstream of the refrigerant flow relative to the heat transfer pipe during cooling operation. The upstream connecting pipe includes: The third pipe has an inner diameter D 31 The third main pipe portion and at least a portion thereof are located inside the heat conducting pipe and have an inner diameter of D 32 The third thin diameter portion is formed of aluminum or an aluminum alloy; as well as The fourth pipe has an inner diameter D 41 The fourth main pipe portion and at least a portion thereof are located inside the third pipe and have an inner diameter of D 42 The fourth thin diameter portion is formed of copper or a copper alloy, Inner diameter D 32 is the inner diameter D 31 Below, inner diameter D 42 Specific inner diameter D 41 Small, inner diameter D 31 / Inner diameter D 32 The value is greater than the inner diameter D 41 / Inner diameter D 42 The value of is small.

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

5. The air conditioner according to claim 1 or 2, characterized in that: The wall thickness T of the second main pipe portion 21 is the wall thickness T of the first main pipe portion 11 More than 1 / 3 of the total.

6. The air conditioner according to claim 1 or 2, characterized in that: The area density of the second main pipe portion is greater than the area density of the first main pipe portion.

7. The air conditioner according to claim 3, wherein The wall thickness T of the fourth main pipe portion 41 is the wall thickness T of the third main pipe portion 31 More than 1 / 3 of the total.

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

9. The air conditioner according to claim 1 or 2, characterized in that: The inner diameter D of the first main pipe portion 11 than the inner diameter D of the second main pipe portion 21 small, and the inner diameter D of the second main pipe portion 21 Smaller than the inner diameter of the heat pipe.

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

11. The air conditioner according to claim 1 or 2, characterized in that: The inner diameter D of the first thin-diameter portion 12 than the inner diameter D of the second thinner portion 22 big.

12. The air conditioner according to claim 3, wherein The inner diameter D of the third thin-diameter portion 32 than the inner diameter D of the fourth thinner portion 42 big.

13. The air conditioner according to claim 1 or 2, characterized in that: Inner diameter D 11 The inner diameter D is the inner diameter of the end portion of the first main pipe portion on the first small diameter portion side. 12 is the inner diameter of the smallest portion of the first thin-diameter portion, Inner diameter D 21 The inner diameter D is the inner diameter of the end portion of the second main pipe portion on the second small diameter portion side. 22 It is the inner diameter of the part with the smallest inner diameter in the second thin-diameter portion.

14. The air conditioner according to claim 4, wherein Inner diameter D 31 The inner diameter D is the inner diameter of the end portion of the third main pipe portion on the side of the third small diameter portion. 32 is the inner diameter of the smallest portion of the third thin-diameter portion, Inner diameter D 41 is the inner diameter of the end portion of the fourth main pipe portion on the fourth thin-diameter portion side, and the inner diameter D 42 It is the inner diameter of the smallest portion in the fourth thin-diameter portion.

Images