Refrigeration Cycle Equipment

Abstract

A refrigeration cycle device having high resistance to vibration of refrigerant piping and capable of reducing manufacturing costs. [Solution] An outdoor unit 100 of a refrigeration cycle device equipped with a compressor 2, a heat source side heat exchanger 4, a pressure reducer 5a, a gas side stop valve 18 and a liquid side stop valve 19, comprising a first metal member 11 arranged in a gas side refrigerant circuit 10A connecting the gas side stop valve 18 and the heat source side heat exchanger 4 at least via the compressor 2, a second metal member 12 arranged in a liquid side refrigerant circuit 10B connecting the heat source side heat exchanger 4 and the liquid side stop valve 19 at least via the pressure reducer 5a, a first copper tube 13 joined to the first metal member 11, and a second copper tube 14 joined to the second metal member 12, the first metal member 11 and the second metal member 12 being made of iron, an iron alloy or stainless steel, the first copper tube 13 being made of a copper alloy containing alloy elements, and the second copper tube 14 being made of copper not containing alloy elements or a copper alloy having a lower content of alloy elements than the first copper tube 13.

Description

[Technical field]

[0001] The present invention relates to a refrigeration cycle apparatus including a refrigerant piping assembly in which a copper-based refrigerant piping is joined to an iron-based refrigerant piping made of stainless steel or the like, and in particular to an outdoor unit of a refrigeration cycle apparatus. [Background technology]

[0002] Refrigeration and air conditioning equipment, such as air conditioners, freezers, and refrigeration equipment, includes a refrigerant circuit that circulates a refrigerant to perform a refrigeration cycle. Devices such as a compressor, a condenser, a pressure reducer, and an evaporator are connected to the refrigerant circuit via refrigerant piping. Conventionally, the refrigerant piping is made of copper, such as phosphorus-deoxidized copper. In addition, devices such as heat transfer tubes of heat exchangers, oil separators, and valves are often made of copper as well.

[0003] Patent Document 1 describes a copper alloy tube for heat exchangers that has better bending workability and heat resistance than conventional phosphorus deoxidized copper. Co, Sn, Zn, Ni, P, etc. are actively added to this copper alloy tube for heat exchangers. The mechanical properties of this copper alloy tube for heat exchangers are improved by precipitation strengthening and solid solution strengthening due to the addition of alloy elements. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5111922 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, the price of copper has been rising, and the material costs of the refrigerant piping and equipment that form the refrigerant circuit are increasing. Therefore, costs can be reduced by changing the materials of the refrigerant piping and equipment that form the refrigerant circuit from copper-based materials such as phosphorus deoxidized copper to iron-based materials such as stainless steel.

[0006] However, there are several obstacles in terms of performance and construction to completely convert the materials of the refrigerant piping and equipment that make up the refrigerant circuit to iron-based metals. Therefore, for the time being, it is expected that the conventional copper-based refrigerant piping and equipment will coexist with iron-based refrigerant piping and equipment made of stainless steel or other materials.

[0007] When ferrous refrigerant piping and equipment such as stainless steel coexist, it is necessary to properly join these dissimilar metals. However, it is known that joining copper to stainless steel and the like is not easy due to differences in physical properties and the presence of oxide films. It is desirable to perform these joining operations in a furnace with a controlled atmosphere, rather than in the air. On the other hand, it is desirable to be able to easily join copper to copper using conventional equipment or on-site.

[0008] In response to such problems, a solution has been devised in which devices forming a refrigerant circuit of a refrigeration cycle device are connected to each other by a refrigerant piping assembly. A refrigerant piping assembly is a component in which a copper tube made of copper or a copper alloy is joined to an iron-based refrigerant piping. The refrigerant piping assembly is obtained by joining an end of a copper tube to an end of an iron-based refrigerant piping by furnace brazing. If the refrigerant piping assembly is manufactured in advance in an appropriate atmosphere and then connected to devices using existing facilities, a low-cost refrigerant circuit in which the iron-based refrigerant piping is appropriately joined can be easily formed.

[0009] However, even when such measures are taken, there remains a problem regarding the strength of the copper tubes of the refrigerant piping assembly. In a refrigeration cycle device, vibrations during operation of the equipment near the compressor and valves that perform switching operations affect the copper tubes. If the strength of the copper tubes is low, there is a risk of fatigue failure. Repeated stress from vibrations can cause the refrigerant piping assembly connected to the equipment to fall off, or the copper tubes to break.

[0010] In particular, since the refrigerant piping assembly is formed by furnace brazing at high temperatures of about 800 to 1200°C for a long period of time of about 20 to 30 minutes, the copper tubes are significantly affected by heat. The crystal grains tend to become coarse, and the tensile strength and fatigue strength tend to decrease. If conventional phosphorus-deoxidized copper brazed in a furnace is used near compressors that generate continuous vibrations or valves that generate intermittent vibrations when switching, the risk of fatigue failure increases.

[0011] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide a refrigeration cycle device that has high resistance to vibration of refrigerant piping and can be manufactured at reduced costs. [Means for solving the problem]

[0012] In order to solve the above problems, the outdoor unit of a refrigeration cycle device of the present invention is an outdoor unit of a refrigeration cycle device equipped with a compressor, a heat source side heat exchanger, a pressure reducer, a gas side stop valve, and a liquid side stop valve, and comprises a first metal member arranged in a gas side refrigerant circuit connecting the gas side stop valve and the heat source side heat exchanger at least via the compressor, a second metal member arranged in a liquid side refrigerant circuit connecting the heat source side heat exchanger and the liquid side stop valve at least via the pressure reducer, a first copper tube joined to the first metal member, and a second copper tube joined to the second metal member, wherein the first metal member and the second metal member are made of iron, an iron alloy, or stainless steel, the first copper tube is made of a copper alloy containing alloy elements, and the second copper tube is made of copper not containing the alloy elements or a copper alloy having a lower content of the alloy elements than the first copper tube. Effect of the Invention

[0013] According to the present invention, it is possible to provide a refrigeration cycle apparatus in which the resistance to vibration of the refrigerant piping is high and the manufacturing costs are reduced. [Brief description of the drawings]

[0014] [Figure 1] 1 is a diagram showing a refrigerant circuit provided in a refrigeration cycle device according to a first embodiment. [Diagram 2] FIG. 6 is a diagram showing a refrigerant circuit provided in a refrigeration cycle device according to a second embodiment. [Diagram 3] FIG. 11 is a diagram showing a refrigerant circuit provided in a refrigeration cycle device according to a third embodiment. [Figure 4] FIG. 13 is a diagram showing a refrigerant circuit provided in a refrigeration cycle device according to a fourth embodiment. [Diagram 5] FIG. 13 is a diagram showing a refrigerant circuit provided in a refrigeration cycle device according to a fifth embodiment. [Figure 6] FIG. 13 is a diagram showing a refrigerant circuit provided in a refrigeration cycle device according to a sixth embodiment. [Figure 7] FIG. 13 is a diagram showing a refrigerant circuit provided in a refrigeration cycle device according to a seventh embodiment. [Figure 8] FIG. 13 is a diagram showing a refrigerant circuit provided in a refrigeration cycle device according to an eighth embodiment. [Figure 9] FIG. 13 is a graph showing the results of measuring the fatigue characteristics of copper-based refrigerant piping. [Figure 10] FIG. 2 is a diagram showing an example of a joint between an iron-based refrigerant pipe and a copper pipe. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, a refrigeration cycle device according to an embodiment of the present invention will be described. Note that the same reference numerals are used to designate the same components in the following drawings, and duplicated explanations will be omitted.

[0016] First Embodiment Fig. 1 is a diagram showing a refrigerant circuit provided in a refrigeration cycle apparatus according to a first embodiment of the present invention. Fig. 1 shows an example of a refrigerant circuit provided in an air conditioner, which is an example of a refrigeration cycle apparatus. As shown in Fig. 1, the air conditioner 1 includes an outdoor unit 100 installed outdoors, and an indoor unit 200 installed on a wall or the like inside the room.

[0017] The air conditioner 1 is a device that adjusts the temperature and humidity of a space by blowing out heated air, cooled air, dehumidified air, etc. A refrigerant circulates between the outdoor unit 100 and the indoor unit 200 through a refrigerant pipe. In the outdoor unit 100, heat exchange occurs between the refrigerant and outside air. In the indoor unit 200, heat exchange occurs between the refrigerant and indoor air. The indoor unit 200 adjusts the temperature and humidity in the room by exchanging heat between the air drawn in from inside the room and the refrigerant and then blowing the air out into the room.

[0018] As shown in Fig. 1, the air conditioner 1 includes a refrigerant circuit 10 that constitutes a heat pump. The refrigerant circuit 10 executes a refrigeration cycle for cooling operation, heating operation, dehumidification operation, etc. The refrigerant circuit 10 includes devices such as a compressor 2, a four-way valve 3, an outdoor heat exchanger 4, an outdoor expansion valve 5a, an indoor expansion valve 5b, an indoor heat exchanger 6, an accumulator 7, and an oil separator 8.

[0019] These devices are connected to each other via refrigerant piping that allows the refrigerant to flow. A gas pipe, which is the refrigerant piping, is connected to the outdoor unit 100 and the indoor unit 200 via a gas side check valve 18, and a liquid pipe, which is the refrigerant piping, is connected to the outdoor unit 100 and the indoor unit 200 via a liquid side check valve 19. A refrigerant circuit 10, which is a closed circuit in which the refrigerant circulates, is formed between the outdoor unit 100 and the indoor unit 200 by these devices and refrigerant piping.

[0020] A refrigerant is sealed in the refrigerant circuit 10. The refrigerant circulates through the refrigerant circuit 10 and exchanges heat with indoor air and outdoor air for cooling operation, heating operation, dehumidification operation, etc. The outdoor unit 100 houses a compressor 2, a four-way valve 3, an outdoor heat exchanger 4, an outdoor expansion valve 5a, an accumulator 7, an oil separator 8, an outdoor blower fan 16, etc. The indoor unit 200 houses an indoor expansion valve 5b, an indoor heat exchanger 6, an indoor blower fan 17, etc.

[0021] The compressor 2 is a device that compresses a refrigerant, sucking in a low-pressure gas refrigerant, adiabatically compressing the gas refrigerant, and discharging a high-pressure gas refrigerant. The compressor 2 may be configured to variably control the amount of refrigerant circulated by inverter control. The compressor 2 may be a suitable type of hermetic electric compressor, such as a scroll type, single rotary type, twin rotary type, swing type, piston type, screw type, centrifugal type, etc. However, the scroll type or twin rotary type is preferable in terms of less vibration during operation.

[0022] The four-way valve 3 has four ports and a valve body that switches the connection of the flow paths between the ports, and the connection of the flow paths between the ports is changed depending on the operation mode, such as cooling operation or heating operation. The four-way valve 3 switches the circulation direction in the refrigerant circuit 10 of the refrigerant discharged from the compressor 2. In Fig. 2, the solid arrow indicates the circulation direction of the refrigerant during cooling operation. The dashed arrow indicates the circulation direction of the refrigerant during heating operation.

[0023] The outdoor heat exchanger 4 is a heat exchanger that exchanges heat between the refrigerant and the outside air, and functions as a condenser during cooling operation and as an evaporator during heating operation. The outdoor blower fan 16 blows outside air to the outdoor heat exchanger 4 to promote heat exchange. The outdoor blower fan 16 is, for example, a propeller fan. The outdoor expansion valve 5a is an electronically controlled valve whose opening is adjustable, and functions as a pressure reducer that expands the refrigerant during heating operation. In addition, if the indoor expansion valve 5b is not provided, the outdoor expansion valve 5a also functions as a pressure reducer that expands the refrigerant during cooling operation.

[0024] In Fig. 1, the outdoor heat exchanger 4 includes a main body 4a and a header pipe 4b. A distributor 4c is connected to the outdoor expansion valve 5a side of the main body 4a via a refrigerant piping. The main body 4a is a cross fin tube type heat exchanger that exchanges heat between parallel flows, and includes a plurality of heat transfer tubes through which the refrigerant flows, and a plurality of fins joined to the heat transfer tubes. The heat transfer tubes and fins are made of, for example, copper, copper alloy, aluminum alloy, or the like.

[0025] The header pipe 4b is a device that splits one flow path into multiple flow paths or merges multiple flow paths into one flow path depending on the refrigerant flow direction. The header pipe 4b has an opening on the four-way valve 3 side that forms one flow path, and refrigerant piping is connected between the header pipe 4b and the four-way valve 3. The header pipe 4b has an opening on the main body 4a side that forms multiple flow paths, and a heat transfer tube of the main body 4a is connected to the opening.

[0026] The distributor 4c is a device that merges multiple flow paths into one flow path or splits one flow path into multiple flow paths depending on the refrigerant flow direction. The distributor 4c has an opening on the main body 4a side that forms multiple flow paths, and refrigerant piping is connected between the opening and the heat transfer tube of the main body 4a. The distributor 4c has an opening on the outdoor expansion valve 5a side that forms multiple flow paths, and refrigerant piping is connected between the opening and the outdoor expansion valve 5a.

[0027] The indoor expansion valve 5b acts as a pressure reducer that expands the refrigerant during cooling operation. The indoor heat exchanger 6 is a heat exchanger that exchanges heat between the refrigerant and the indoor air, and acts as an evaporator during cooling operation and as a condenser during heating operation. The indoor blower fan 17 blows air to the indoor heat exchanger 6 to promote heat exchange, and blows the air that has exchanged heat with the refrigerant into the room. The indoor blower fan 17 is, for example, a cylindrical cross-flow fan.

[0028] The accumulator 7 is a tank-shaped device that separates gas refrigerant from liquid refrigerant, and separates and stores the liquid refrigerant contained in the gas refrigerant. The accumulator 7 removes liquid refrigerant that has not been completely evaporated from the gas refrigerant on the suction side of the compressor 2. By removing the liquid refrigerant, liquid compression in the compressor 2, which can cause abnormal noise and breakdowns, is prevented.

[0029] The oil separator 8 is a device that separates the refrigerant from the refrigerating machine oil. The oil separator 8 separates the refrigerating machine oil discharged together with the refrigerant from the compressor 2 from the refrigerant. The refrigerating machine oil separated by the oil separator 8 is refluxed to the compressor 2 without circulating through the refrigerant circuit 10. By separating and refluxing the refrigerating machine oil, oil shortage in the compressor 2 and performance degradation due to mixing into the refrigerant circulating through the refrigerant circuit 10 are prevented.

[0030] The cooling operation of the air conditioner 1 is performed as follows. The high-temperature and high-pressure gas refrigerant adiabatically compressed by the compressor 2 is sent to the outdoor heat exchanger 4 through the four-way valve 3. The high-temperature and high-pressure gas refrigerant is condensed into a liquid refrigerant by heat exchange with the outside air in the outdoor heat exchanger 4 acting as a condenser. The liquid refrigerant is decompressed and expanded by the indoor expansion valve 5b to become a low-temperature and low-pressure gas-liquid two-phase refrigerant containing a small amount of gas refrigerant.

[0031] The low-temperature and low-pressure gas-liquid two-phase refrigerant is sent to the indoor heat exchanger 6. The gas-liquid two-phase refrigerant evaporates by heat exchange with the indoor air in the indoor heat exchanger 6 acting as an evaporator to become a low-temperature and low-pressure gas refrigerant. The low-temperature and low-pressure gas refrigerant passes through the four-way valve 3 and returns to the compressor 2 after the liquid refrigerant is separated by the accumulator 7. The indoor air has its heat taken away by heat exchange with the refrigerant in the indoor heat exchanger 6 acting as an evaporator. Such a cycle is repeated, and the room is cooled.

[0032] The heating operation of the air conditioner 1 is performed in a cycle opposite to the cooling operation. The high-temperature and high-pressure gas refrigerant adiabatically compressed and discharged by the compressor 2 is sent to the indoor heat exchanger 6 by switching the four-way valve 3. The high-temperature and high-pressure gas refrigerant is cooled by heat exchange with the indoor air in the indoor heat exchanger 6 acting as a condenser to become a liquid refrigerant. The liquid refrigerant is decompressed by the outdoor expansion valve 5a to become a low-temperature and low-pressure liquid refrigerant.

[0033] The low-temperature, low-pressure liquid refrigerant is sent to the outdoor heat exchanger 4. The low-temperature, low-pressure liquid refrigerant evaporates through heat exchange with the outside air in the outdoor heat exchanger 4, which functions as an evaporator, and becomes a low-temperature, low-pressure gas refrigerant. The low-temperature, low-pressure gas refrigerant passes through the four-way valve 3, and after the liquid refrigerant is separated in the accumulator 7, it returns to the compressor 2. The indoor air is given heat through heat exchange with the refrigerant in the indoor heat exchanger 6, which functions as a condenser. This cycle is repeated to heat the room.

[0034] In the air conditioner 1 according to this embodiment, the refrigerant circuit 10 may contain a single refrigerant consisting of a single refrigerant component, or a mixed refrigerant consisting of a plurality of refrigerant components. As the mixed refrigerant, an azeotropic mixed refrigerant or a non-azeotropic mixed refrigerant may be used. As the refrigerant, hydrofluorocarbons (HFCs), hydrofluoroolefins (HFOs), CO 2 The refrigerant may be one or more of a refrigerant, a hydrocarbon, an ether, a fluoroether, a fluoroalkene, etc. The refrigerant may contain additives such as a stabilizer that suppresses decomposition of the refrigerant components, and a polymerization inhibitor that suppresses polymerization of the refrigerant components.

[0035] In the air conditioner 1 according to this embodiment, a predetermined refrigeration oil is injected into the compressor 2. The refrigeration oil is sucked from an oil reservoir during operation of the compressor 2 and supplied to sliding parts such as the compression mechanism and bearings. The refrigeration oil lubricates, cools, and seals the sliding parts. As the refrigeration oil, polyol ester oil, polyvinyl ether oil, polyalkylene glycol oil, and the like can be used. The refrigeration oil may contain additives such as an acid scavenger, an antioxidant, an extreme pressure agent, a stabilizer, an antifoaming agent, and a metal deactivator.

[0036] As shown in Fig. 1, in the air conditioner 1 according to this embodiment, at least some sections of the refrigerant circuit 10 are formed by an assembly. The assembly is a component in which a copper pipe is joined to an iron-based metal member. The metal member is a metal member that forms part of the refrigerant circuit 10, and is composed of refrigerant piping that forms the refrigerant circuit 10, parts of equipment that executes the refrigeration cycle, for example, the main body of the equipment, piping joined to a connection part of the equipment, and other members.

[0037] The assembly can be connected to one or more of the metal members that form the refrigerant circuit 10. In FIG. 1, the connection parts of the devices that form the refrigerant circuit 10, such as the compressor 2 and the accumulator 7, are made of a copper member 20. The copper member 20 is a member that is joined to the main body of the device or to the connection parts of the device, and is provided integrally with the device. The copper member 20 is made of, for example, copper or a copper alloy, such as phosphorus-deoxidized copper. The assembly is joined to such a metal member by homogeneous metal joining.

[0038] 1, refrigerant piping assemblies 10a and 10b are provided as assemblies. The refrigerant piping assemblies 10a and 10b are refrigerant piping in which copper pipes 13 and 14 are joined to iron-based refrigerant piping 11 and 12 constituting an iron-based metal member. The refrigerant piping assemblies 10a and 10b function as refrigerant piping, and can be connected to refrigerant piping that forms the refrigerant circuit 10 and to devices that form the refrigerant circuit 10.

[0039] The refrigerant pipe assemblies 10a, 10b are pre-assembled parts of refrigerant pipes, and are formed from iron-based refrigerant pipes 11, 12 and copper pipes 13, 14. The iron-based refrigerant pipes 11, 12 and the copper pipes 13, 14 are joined to each other by furnace brazing. The furnace brazing can be performed in an atmosphere where the oxygen concentration, moisture content, hydrogen concentration, etc. are controlled, for example.

[0040] As the iron-based refrigerant pipes 11 and 12, iron pipes, iron alloy pipes, or stainless steel pipes can be used. Examples of iron and iron alloys include steel, carbon steel, and alloy steel. Examples of stainless steel include austenitic stainless steel such as SUS304. When the iron-based refrigerant pipes 11 and 12 are used, the raw material cost can be reduced in some cases compared to the copper-based case.

[0041] The copper tubes 13 and 14 may be copper tubes or copper alloy tubes. Examples of copper include phosphorus deoxidized copper, oxygen-free copper, and tough pitch copper. Examples of copper alloys include alloys containing copper as the main component and at least one of phosphorus (P), cobalt (Co), tin (Sn), zinc (Zn), nickel (Ni), zirconium (Zr), and iron (Fe) as alloying elements. The use of the copper tubes 13 and 14 facilitates connection to existing copper-based refrigerant piping and equipment that form the refrigerant circuit 10. In addition, galvanic corrosion caused by joining dissimilar metals together is suppressed.

[0042] The copper alloy may be a copper-based alloy containing Co, Sn, Zn, Ni, Zr, and Fe at a content of, for example, 0.01% by mass or more. The copper alloy may be a copper-based alloy containing phosphorus (P) at a content of more than 0.040% by mass. The copper alloy may be a solid-solution strengthened copper alloy in which alloy elements are dissolved in solid solution, or a precipitation strengthened copper alloy in which alloy elements at or above the solid solubility limit are precipitated. The use of such a copper alloy improves mechanical properties such as tensile strength and fatigue strength, so that fatigue failure of the copper tube can be reduced even if vibration occurs during operation of the equipment.

[0043] The refrigerant piping assemblies 10a, 10b can be joined to other refrigerant piping and devices forming the refrigerant circuit 10 by, for example, air brazing, flare connection, welding, etc. When assembling the refrigerant circuit 10, the copper tubes 13, 14 on the end sides of the refrigerant piping assemblies 10a, 10b formed by furnace brazing can be easily joined to existing copper-based refrigerant piping and devices using conventionally used equipment, etc. In addition, since it is possible to avoid heating the copper tubes 13, 14 in the furnace, it is possible to suppress a decrease in strength due to coarsening of crystal grains.

[0044] The refrigerant piping assemblies 10a, 10b may be formed by joining the copper pipes 13, 14 to one end of the iron-based refrigerant pipes 11, 12, or may be formed by joining the copper pipes 13, 14 to both ends of the iron-based refrigerant pipes 11, 12. However, when the refrigerant piping assemblies 10a, 10b are to be connected to copper-based refrigerant pipes or equipment, it is preferable that the copper pipes 13, 14 are previously joined to the corresponding ends of the refrigerant piping assemblies 10a, 10b.

[0045] In FIG. 1, as the refrigerant piping assemblies 10a, 10b, a first refrigerant piping assembly 10a and a second refrigerant piping assembly 10b are connected between devices on a refrigerant circuit 10.

[0046] The first refrigerant piping assembly 10a is formed by joining a first copper tube 13 made of a copper alloy to an iron-based first refrigerant piping 11 made of iron, an iron alloy, or stainless steel. The first copper tube 13 is formed of a copper alloy containing one or more alloy elements selected from Co, Sn, Zn, Ni, Zr, and Fe, and more than 0.040 mass% P. The first copper tube 13 is a refrigerant piping made of a copper alloy whose mechanical properties, such as tensile strength and fatigue strength, have been improved by solid solution strengthening and precipitation strengthening due to the addition of alloy elements.

[0047] The first copper tube 13 may contain, for example, Co at a content rate of more than 0.01 mass% and not more than 0.5 mass%, preferably 0.04 mass% or more and not more than 0.2 mass%. The first copper tube 13 may contain Sn at a content rate of more than 0.01 mass% and not more than 1.0 mass%, preferably 0.05 mass% or more and not more than 0.8 mass%. The first copper tube 13 may contain Zn at a content rate of more than 0.01 mass% and not more than 0.5 mass%, preferably 0.02 mass% or more and not more than 0.2 mass%. The first copper tube 13 may contain Ni at a content rate of more than 0.01 mass% and not more than 1.0 mass%, preferably 0.02 mass% or more and not more than 0.5 mass%. The first copper tube 13 may contain Zr at a content rate of more than 0.01 mass% and not more than 0.5 mass%, preferably 0.04 mass% or more and not more than 0.1 mass%. The first copper tube 13 may contain Fe at a content rate of more than 0.01 mass% and not more than 5.0 mass%, preferably 1. mass% or more and not more than 3.0 mass%.

[0048] The Cu content of the first copper tube 13 is preferably 95 mass% or more, more preferably 97 mass% or more, and even more preferably 99 mass% or more. The P content may be 0.015 mass% or more and 0.040 mass% or less, or may be more than 0.040 mass%. The content of the alloy elements of the first copper tube 13 relative to the base metal, which is the main component of the alloy elements, is preferably lower than the content of the alloy elements of the iron-based first refrigerant pipe 11 relative to the base metal, which is the main component of the alloy elements.

[0049] The second refrigerant piping assembly 10b is formed by joining a second copper tube 14 made of copper or a copper alloy to an iron-based second refrigerant piping 12 made of iron, an iron alloy, or stainless steel. The second copper tube 14 is formed from copper that is substantially free of one or more alloying elements selected from the group consisting of Co, Sn, Zn, Ni, Zr, and Fe, which have been actively added thereto, or a copper alloy in which the content of these alloying elements relative to the base metal, which is the main component, is lower than that of the first copper tube 13. The second copper tube 14 can be formed from phosphorus-deoxidized copper, low-cost low-alloy copper containing fewer alloying elements, or the like.

[0050] 1, a refrigerant circuit 10 is formed by connecting, via refrigerant piping, a compressor 2, a four-way valve 3, an outdoor heat exchanger 4 which is a heat source side heat exchanger, an outdoor expansion valve 5a which is a pressure reducer, an indoor expansion valve 5b, an indoor heat exchanger 6 which is a utilization side heat exchanger, an accumulator 7, an oil separator 8, a gas side stop valve 18, and a liquid side stop valve 19. The refrigerant circuit 10 is made up of at least a gas side refrigerant circuit 10A, a liquid side refrigerant circuit 10B, and a utilization side refrigerant circuit 10C.

[0051] The gas side refrigerant circuit 10A connects the compressor 2 and the outdoor heat exchanger 4, which is a heat source side heat exchanger, in the refrigerant circuit 10 without passing through the outdoor expansion valve 5a, which is a pressure reducer. The gas side refrigerant circuit 10A connects the gas side stop valve 18 and the outdoor heat exchanger 4 via the compressor 2 etc. A first metal member to which a first copper tube 13 is joined is disposed in at least a portion of the gas side refrigerant circuit 10A.

[0052] The liquid side refrigerant circuit 10B connects the outdoor heat exchanger 4 and the liquid side stop valve 19 via the outdoor expansion valve 5a etc. A second metal member to which a second copper tube 14 is joined is disposed in at least a portion of the liquid side refrigerant circuit 10B.

[0053] The utilization side refrigerant circuit 10C connects the indoor end of the gas side refrigerant circuit 10A and the indoor end of the liquid side refrigerant circuit 10B via a utilization side heat exchanger such as the indoor heat exchanger 6. The utilization side refrigerant circuit 10C is a refrigerant circuit built into the indoor unit 200. A first metal member to which a first copper tube 13 is joined and a second metal member to which a second copper tube 14 is joined can be disposed in at least a portion of the utilization side refrigerant circuit 10C, as required.

[0054] As shown in FIG. 1, the first refrigerant piping assembly 10a is a gas side refrigerant circuit 10A, and can be connected to one or more sections between the accumulator 7 and the compressor 2, between the compressor 2 and the oil separator 8, between the oil separator 8 and the four-way valve 3, between the four-way valve 3 and the gas side stop valve 18, between the four-way valve 3 and the accumulator 7, and between the four-way valve 3 and the outdoor heat exchanger 4.

[0055] That is, the iron-based first refrigerant piping 11, which is an iron-based first metal member, can be disposed between the accumulator 7 and the compressor 2, between the compressor 2 and the oil separator 8, between the oil separator 8 and the four-way valve 3, between the four-way valve 3 and the gas side check valve 18, between the four-way valve 3 and the accumulator 7, or between the four-way valve 3 and the outdoor heat exchanger 4 by incorporating the first refrigerant piping assembly 10a. The first copper tube 13 is joined in advance to an end of such iron-based first refrigerant piping 11. With respect to the outdoor heat exchanger 4, the first copper tube 13 can be connected to the four-way valve 3 side of the header pipe 4b, or the like.

[0056] These sections are close to the compressor 2, which generates continuous vibrations during operation, and the four-way valve 3, which generates intermittent vibrations during switching. If unreinforced refrigerant piping made of phosphorus-deoxidized copper or the like is connected to such sections, there is a risk of fatigue failure due to repeated stress caused by vibrations during operation of the equipment. In contrast, the first refrigerant piping assembly 10a can suppress fatigue failure due to vibration because the first copper tube 13 constituting the end portion is reinforced with alloy elements. This reduces the risk of the first refrigerant piping assembly 10a falling off and the breakage of the portion made of copper-based metal.

[0057] On the other hand, the second refrigerant piping assembly 10b is a liquid side refrigerant circuit 10B, and can be connected to one or more sections between the outdoor heat exchanger 4 and the outdoor expansion valve 5a, and between the outdoor expansion valve 5a and the liquid side stop valve 19.

[0058] That is, the iron-based second refrigerant piping 12, which is an iron-based second metal member, can be disposed between the outdoor heat exchanger 4 and the outdoor expansion valve 5a, or between the outdoor expansion valve 5a and the liquid side check valve 19, by incorporating the second refrigerant piping assembly 10b. The second copper tube 14 is joined in advance to an end of such iron-based second refrigerant piping 12. With respect to the outdoor heat exchanger 4, the second copper tube 14 can be connected to the distributor 4c side of the main body 4a, the main body 4a side of the distributor 4c, the outdoor expansion valve 5a side, or the like.

[0059] These sections are not close to the compressor 2, which generates continuous vibrations during operation, or the four-way valve 3, which generates intermittent vibrations during switching. Because the outdoor heat exchanger 4 is interposed between these sections and the compressor 2 or the four-way valve 3, the vibrations during operation of the equipment are unlikely to reach them. For these sections, phosphorus-deoxidized copper tubes that have been used conventionally, low-alloy copper tubes that contain fewer alloy elements and therefore reduce raw material costs, and the like can be used as the ends of the refrigerant piping assembly 10b. By using such refrigerant piping, the refrigerant circuit 10 can be formed at low cost without fatigue failure due to vibration.

[0060] Furthermore, the first refrigerant piping assembly 10a and the second refrigerant piping assembly 10b can also be connected to one or more sections of the user-side refrigerant circuit 10C between the indoor heat exchanger 6 and the indoor expansion valve 5b, between the indoor expansion valve 5b and the liquid-side check valve 19, and between the indoor heat exchanger 6 and the gas-side check valve 18. In FIG. 1, the second refrigerant piping assembly 10b is connected to these sections, but in cases where vibration or strength of the indoor unit 200 is a problem, the first refrigerant piping assembly 10a may be connected to these sections.

[0061] In the refrigerant circuit 10, the length along the center line of the first copper tube 13 is preferably shorter than the length along the center line of the iron-based first refrigerant pipe 11. In addition, the length along the center line of the second copper tube is preferably shorter than the length along the center line of the iron-based second refrigerant pipe 12.

[0062] With such a length relationship, the length ratio of the iron-based refrigerant piping in the first refrigerant piping assembly 10a and the second refrigerant piping assembly 10b is larger than that of the copper pipes, so that the first refrigerant piping assembly 10a and the second refrigerant piping assembly 10b can be made more cost-effective.

[0063] However, in the section connecting the oil outlet of the oil separator 8 and the compressor 2, the length along the center line of the iron-based first refrigerant piping 11 is preferably set shorter than the length along the center line of the first copper tube 13 joined to the iron-based first refrigerant piping 11. In the section connecting the oil outlet of the oil separator 8 and the compressor 2, the first refrigerant piping assembly 10a may not be provided, and a copper-based refrigerant piping made of copper or a copper alloy may be connected.

[0064] The section connecting the oil outlet of the oil separator 8 and the compressor 2 is a section where the refrigeration oil is returned to the compressor 2, and is generally provided to be short. Therefore, this section is a section where there is little need to convert the copper-based refrigerant piping to an iron-based refrigerant piping. Such a length relationship can improve the degree of freedom in designing the refrigerant circuit 10 and reduce the overall cost.

[0065] In the refrigerant circuit 10, the pipe wall thickness of the iron-based first refrigerant pipe 11 is preferably set to be thicker than the pipe wall thickness of the iron-based second refrigerant pipe 12. In addition, the pipe wall thickness of the first copper pipe 13 is preferably set to be thicker than the pipe wall thickness of the iron-based first refrigerant pipe 11 and the pipe wall thickness of the iron-based second refrigerant pipe 12. In addition, the pipe wall thickness of the second copper pipe 14 is preferably set to be thicker than the pipe wall thickness of the iron-based first refrigerant pipe 11 and the pipe wall thickness of the iron-based second refrigerant pipe 12.

[0066] With such a thickness relationship, the thickness of the refrigerant pipe is set relatively thick in the section where the gas refrigerant mainly flows, so that the pressure resistance of the refrigerant pipe can be appropriately ensured. Also, in the first refrigerant piping assembly 10a and the second refrigerant piping assembly 10b, the thickness ratio of the iron-based refrigerant pipe is larger than that of the copper pipe, so that the first refrigerant piping assembly 10a and the second refrigerant piping assembly 10b can be further reduced in cost.

[0067] When the first refrigerant piping assembly 10a is connected to the compressor 2, that is, when the iron-based first refrigerant piping 11 forms a piping connected between the compressor 2 and the accumulator 7, between the compressor 2 and the oil separator 8, or between the compressor 2 and the four-way valve 3, and the first copper tube 13 is joined to the discharge side or suction side of the compressor 2, it is preferable that the compressor 2 is a scroll compressor or a twin rotary compressor.

[0068] With this type of compressor 2, vibrations generated during operation of the compressor 2 are smaller than those of a single rotary type, a swing type, etc. Therefore, even when the first copper tube 13 constituting the first refrigerant piping assembly 10a is strengthened by adding an alloy element, fatigue failure of the first refrigerant piping assembly 10a and the first copper tube 13 constituting the first refrigerant piping assembly 10a can be further reduced.

[0069] According to such an air conditioner 1, the refrigerant circuit 10 is formed using the refrigerant piping assemblies 10a, 10b, so that the copper pipe and the iron-based refrigerant pipe are previously joined by furnace brazing in a controlled atmosphere, and then the end of the copper pipe joined to the iron-based refrigerant pipe can be connected to existing copper-based refrigerant pipes and equipment in any atmosphere such as air. Since a part of the refrigerant circuit 10 is replaced with the iron-based refrigerant pipe, it is possible to connect to existing copper-based refrigerant pipes and equipment using conventional equipment and methods, while reducing material costs. Therefore, despite the presence of joints between dissimilar metals, the iron-based refrigerant pipes are appropriately joined to the copper-based refrigerant pipes and equipment, and a refrigeration cycle device with reduced manufacturing costs can be provided.

[0070] Furthermore, the refrigerant pipe assemblies 10a, 10b use different chemical compositions for the copper pipes that make up the ends depending on the positional relationship with the equipment that generates vibration, thereby improving the resistance of the refrigerant pipes to vibration. The tensile strength and fatigue strength of the copper pipes connected to the compressor 2 and four-way valve 3, which generate vibration during operation, are strengthened by solid solution strengthening and precipitation strengthening through the addition of alloy elements. On the other hand, the cost of the copper pipes not connected to these is reduced by not adding alloy elements or by reducing them. Therefore, it is possible to provide a refrigeration cycle device with high resistance to vibration of the refrigerant pipes, which is less likely to fall off or break, and which can be manufactured at reduced costs.

[0071] <Second embodiment> Fig. 2 is a diagram showing a refrigerant circuit provided in a refrigeration cycle apparatus according to a second embodiment of the present invention. Fig. 2 shows an example of a refrigerant circuit provided in an air conditioner, which is an example of a refrigeration cycle apparatus. As shown in Fig. 2, the air conditioner 2 can also be provided with an iron-based oil separator 8a made of iron, iron alloy, or stainless steel. The iron-based oil separator 8a can be incorporated into the refrigerant circuit 10 as an assembly. Other major components of the air conditioner 2 are similar to those of the air conditioner 1 described above.

[0072] The iron-based oil separator 8a can be prepared as an oil separator assembly 10c. The oil separator assembly 10c is an assembly in which a first copper tube 13 is joined to the connection part of the iron-based oil separator 8a constituting an iron-based metal member. The oil separator assembly 10c can be connected to the refrigerant piping that forms the refrigerant circuit 10 and to devices that form the refrigerant circuit 10.

[0073] The oil separator assembly 10c is in the form of a pre-assembled part, and is formed from an iron-based oil separator 8a and a first copper tube 13. The first copper tube 13 is formed from a copper alloy containing one or more alloy elements selected from the group consisting of Co, Sn, Zn, Ni, Zr, and Fe, and more than 0.040 mass% P. The first copper tube 13 is made of a copper alloy whose mechanical properties, such as tensile strength and fatigue strength, have been improved by solid solution strengthening and precipitation strengthening due to the addition of alloy elements. The iron-based oil separator 8a and the first copper tube 13 are joined together by furnace brazing.

[0074] The iron-based oil separator 8a may be an oil separator whose body and connecting parts are made of iron, an oil separator whose body and connecting parts are made of iron alloy, or an oil separator whose body and connecting parts are made of stainless steel. The first copper tube 13 may be connected to each port of the iron-based oil separator 8a, or may be connected to the end of an iron-based refrigerant pipe that is previously connected to each port of the iron-based oil separator 8a.

[0075] Examples of iron and iron alloys include steel, carbon steel, alloy steel, etc. Examples of stainless steel include austenitic stainless steel such as SUS304, etc. When an iron-based oil separator 8a is used, the raw material cost can be reduced in some cases compared to the case of a copper-based oil separator.

[0076] The oil separator assembly 10c can be joined to other refrigerant pipes and devices that form the refrigerant circuit 10 by, for example, air brazing, flare connection, welding, etc. When assembling the refrigerant circuit 10, the oil separator assembly 10c formed by furnace brazing can be easily joined to existing copper-based refrigerant pipes and devices using conventionally used equipment, etc. In addition, since it is possible to avoid heating the first copper tube 13 in the furnace, it is possible to prevent a decrease in strength due to coarsening of crystal grains.

[0077] The oil separator assembly 10c may be formed by joining the first copper tube 13 to some of the connecting parts of the iron-based oil separator 8a, or may be formed by joining the first copper tube 13 to all of the connecting parts of the iron-based oil separator 8a. However, when the oil separator assembly 10c is to be connected to copper-based refrigerant piping or equipment, it is preferable that the first copper tube 13 is joined to the corresponding connecting parts of the oil separator assembly 10c.

[0078] 2, the refrigerant circuit 10 is formed by connecting via refrigerant piping a compressor 2, a four-way valve 3, an outdoor heat exchanger 4 which is a heat source side heat exchanger, an outdoor expansion valve 5a which is a pressure reducer, an indoor expansion valve 5b, an indoor heat exchanger 6 which is a user side heat exchanger, an accumulator 7, an iron-based oil separator 8a, a gas side stop valve 18, and a liquid side stop valve 19. The refrigerant circuit 10 is composed of at least a gas side refrigerant circuit 10A, a liquid side refrigerant circuit 10B, and a user side refrigerant circuit 10C.

[0079] 2, the oil separator assembly 10c is a gas side refrigerant circuit 10A, and can be connected between the compressor 2 and the four-way valve 3. That is, an iron-based oil separator 8a constituting an iron-based first metal member can be disposed between the compressor 2 and the four-way valve 3 by incorporating the oil separator assembly 10c. The first copper tube 13 is joined in advance to the connection portion of the iron-based oil separator 8a.

[0080] In addition, the first refrigerant piping assembly 10a is a gas side refrigerant circuit 10A, and can be connected to one or more sections between the accumulator 7 and the compressor 2, between the four-way valve 3 and the gas side stop valve 18, between the four-way valve 3 and the accumulator 7, and between the four-way valve 3 and the outdoor heat exchanger 4.

[0081] That is, the iron-based first refrigerant piping 11, which is an iron-based first metal member, can be disposed between the accumulator 7 and the compressor 2, between the four-way valve 3 and the gas side check valve 18, between the four-way valve 3 and the accumulator 7, or between the four-way valve 3 and the outdoor heat exchanger 4 by incorporating the first refrigerant piping assembly 10a. The first copper tube 13 is joined in advance to an end of such iron-based first refrigerant piping 11. With respect to the outdoor heat exchanger 4, the first copper tube 13 can be connected to the four-way valve 3 side of the header pipe 4b, etc.

[0082] On the other hand, the second refrigerant piping assembly 10b is a liquid side refrigerant circuit 10B, and can be connected to one or more sections between the outdoor heat exchanger 4 and the outdoor expansion valve 5a, and between the outdoor expansion valve 5a and the liquid side stop valve 19.

[0083] That is, the iron-based second refrigerant piping 12, which is an iron-based second metal member, can be disposed between the outdoor heat exchanger 4 and the outdoor expansion valve 5a, or between the outdoor expansion valve 5a and the liquid side check valve 19, by incorporating the second refrigerant piping assembly 10b. The second copper tube 14 is joined in advance to an end of such iron-based second refrigerant piping 12. With respect to the outdoor heat exchanger 4, the second copper tube 14 can be connected to the distributor 4c side of the main body 4a, the main body 4a side of the distributor 4c, the outdoor expansion valve 5a side, or the like.

[0084] Furthermore, the first refrigerant piping assembly 10a and the second refrigerant piping assembly 10b can also be connected to one or more sections of the user-side refrigerant circuit 10C between the indoor heat exchanger 6 and the indoor expansion valve 5b, between the indoor expansion valve 5b and the liquid-side check valve 19, and between the indoor heat exchanger 6 and the gas-side check valve 18. In Fig. 2, the second refrigerant piping assembly 10b is connected to these sections, but in cases where vibration or strength of the indoor unit 200 is a problem, the first refrigerant piping assembly 10a may be connected to these sections.

[0085] In addition, in the refrigerant circuit 10, it is preferable that the length along the center line of the first copper tube 13, the length along the center line of the second copper tube 14, the pipe wall thickness of the iron-based first refrigerant pipe 11, the pipe wall thickness of the iron-based second refrigerant pipe 12, the pipe wall thickness of the first copper tube 13, the pipe wall thickness of the second copper tube 14, and the type of compressor 2 are configured in the same way as in the air conditioner 1 described above.

[0086] According to such an air conditioner 2, the refrigerant circuit 10 is formed using the refrigerant pipe assemblies 10a, 10b and the oil separator assembly 10c, so that the copper pipes are joined to the iron-based refrigerant pipes or the iron-based oil separator in advance by furnace brazing in a controlled atmosphere, and then the ends of the copper pipes joined to the iron-based refrigerant pipes or the iron-based oil separator can be connected to existing copper-based refrigerant pipes or equipment in any atmosphere such as air. Since a part of the refrigerant circuit 10 is replaced with iron-based refrigerant pipes or equipment, it is possible to connect to existing copper-based refrigerant pipes and equipment using conventional equipment and methods, while reducing material costs. Therefore, despite the presence of joints between dissimilar metals, the iron-based refrigerant pipes and equipment are appropriately joined to the copper-based refrigerant pipes and equipment, and a refrigeration cycle device with reduced manufacturing costs can be provided.

[0087] In addition, the refrigerant pipe assemblies 10a, 10b and the oil separator assembly 10c use different chemical compositions for the copper pipes that make up the ends depending on the positional relationship with the equipment that generates vibration, thereby improving the resistance of the refrigerant pipes to vibration. The tensile strength and fatigue strength of the copper pipes connected to the compressor 2 and the four-way valve 3, which generate vibration during operation, are strengthened by solid solution strengthening and precipitation strengthening through the addition of alloy elements. On the other hand, the cost of the copper pipes not connected to these is reduced by not adding alloy elements or by reducing them. Therefore, it is possible to provide a refrigeration cycle device with high resistance to vibration of the refrigerant pipes, which is suppressed in falling off and breaking, and which can be manufactured at reduced costs.

[0088] <Third embodiment> Fig. 3 is a diagram showing a refrigerant circuit provided in a refrigeration cycle apparatus according to a third embodiment of the present invention. Fig. 3 shows an example of a refrigerant circuit provided in an air conditioner, which is an example of a refrigeration cycle apparatus. As shown in Fig. 3, the air conditioner 3 can also be provided with an iron-based four-way valve 3a made of iron, iron alloy, or stainless steel. The iron-based four-way valve 3a can be incorporated into the refrigerant circuit 10 as an assembly. Other major components of the air conditioner 3 are similar to those of the air conditioner 1 described above.

[0089] The iron-based four-way valve 3a can be prepared as a four-way valve assembly 10d. The four-way valve assembly 3d is an assembly in which a first copper tube 13 is joined to the connection part of the iron-based four-way valve 3a constituting an iron-based metal member. The four-way valve assembly 3d can be connected to the refrigerant piping that forms the refrigerant circuit 10 and to the equipment that forms the refrigerant circuit 10.

[0090] The four-way valve assembly 10d is in the form of a pre-assembled part, and is formed from an iron-based four-way valve 3a and a first copper tube 13. The first copper tube 13 is formed from a copper alloy containing one or more alloy elements selected from the group consisting of Co, Sn, Zn, Ni, Zr, and Fe, and more than 0.040 mass% P. The first copper tube 13 is made of a copper alloy whose mechanical properties, such as tensile strength and fatigue strength, have been improved by solid solution strengthening and precipitation strengthening due to the addition of alloy elements. The iron-based four-way valve 3a and the first copper tube 13 are joined to each other by furnace brazing.

[0091] The iron-based four-way valve 3a may be a four-way valve whose main body and connecting parts are made of iron, a four-way valve whose main body and connecting parts are made of iron alloy, or a four-way valve whose main body and connecting parts are made of stainless steel. The first copper pipe 13 may be connected to each port of the iron-based four-way valve 3a, or may be connected to the end of an iron-based refrigerant pipe that is previously connected to each port of the iron-based four-way valve 3a.

[0092] Examples of iron and iron alloys include steel, carbon steel, alloy steel, etc. Examples of stainless steel include austenitic stainless steel such as SUS304, etc. When an iron-based four-way valve 3a is used, the raw material cost may be reduced compared to the case of a copper-based valve.

[0093] The four-way valve assembly 10d can be joined to other refrigerant pipes and devices that form the refrigerant circuit 10 by, for example, air brazing, flare connection, welding, etc. When assembling the refrigerant circuit 10, the four-way valve assembly 10d formed by furnace brazing can be easily joined to existing copper-based refrigerant pipes and devices using conventionally used equipment, etc. In addition, since it is possible to avoid heating the first copper tube 13 in the furnace, it is possible to prevent a decrease in strength due to coarsening of crystal grains.

[0094] The four-way valve assembly 10d may be formed by joining the first copper tube 13 to some of the connections of the iron-based four-way valve 3a, or may be formed by joining the first copper tube 13 to all of the connections of the iron-based four-way valve 3a. However, when the four-way valve assembly 10d is to be connected to copper-based refrigerant piping or equipment, it is preferable that the first copper tube 13 is joined to the corresponding connection of the four-way valve assembly 10d.

[0095] 3, the refrigerant circuit 10 is formed by connecting, via refrigerant piping, a compressor 2, an iron-based four-way valve 3a, an outdoor heat exchanger 4 which is a heat source-side heat exchanger, an outdoor expansion valve 5a which is a pressure reducer, an indoor expansion valve 5b, an indoor heat exchanger 6 which is a user-side heat exchanger, an accumulator 7, an oil separator 8, a gas-side stop valve 18, and a liquid-side stop valve 19. The refrigerant circuit 10 is made up of at least a gas-side refrigerant circuit 10A, a liquid-side refrigerant circuit 10B, and a user-side refrigerant circuit 10C.

[0096] 3, the four-way valve assembly 10d is a gas side refrigerant circuit 10A, and can be connected to the oil separator 8, the gas side stop valve 18, the accumulator 7, and the outdoor heat exchanger 4. That is, the iron-based four-way valve 3a constituting the iron-based first metal member can be disposed in relation to the oil separator 8, the gas side stop valve 18, the accumulator 7, and the outdoor heat exchanger 4 by incorporating the four-way valve assembly 10d. The first copper pipe 13 is joined in advance to the connection portion of the iron-based four-way valve 3a.

[0097] The first refrigerant piping assembly 10a is a gas side refrigerant circuit 10A, and can be connected to one or more sections between the accumulator 7 and the compressor 2 and between the compressor 2 and the oil separator 8.

[0098] That is, the iron-based first refrigerant piping 11, which is an iron-based first metal member, can be disposed between the accumulator 7 and the compressor 2, or between the compressor 2 and the oil separator 8, by incorporating the first refrigerant piping assembly 10a. The first copper tube 13 is joined in advance to an end of such iron-based first refrigerant piping 11. With respect to the outdoor heat exchanger 4, the first copper tube 13 can be connected to the four-way valve 3 side of the header pipe 4b, or the like.

[0099] On the other hand, the second refrigerant piping assembly 10b is a liquid side refrigerant circuit 10B, and can be connected to one or more sections between the outdoor heat exchanger 4 and the outdoor expansion valve 5a, and between the outdoor expansion valve 5a and the liquid side stop valve 19.

[0100] That is, the iron-based second refrigerant piping 12, which is an iron-based second metal member, can be disposed between the outdoor heat exchanger 4 and the outdoor expansion valve 5a, or between the outdoor expansion valve 5a and the liquid side check valve 19, by incorporating the second refrigerant piping assembly 10b. The second copper tube 14 is joined in advance to an end of such iron-based second refrigerant piping 12. With respect to the outdoor heat exchanger 4, the second copper tube 14 can be connected to the distributor 4c side of the main body 4a, the main body 4a side of the distributor 4c, the outdoor expansion valve 5a side, or the like.

[0101] Furthermore, the first refrigerant piping assembly 10a and the second refrigerant piping assembly 10b can also be connected to one or more sections of the user-side refrigerant circuit 10C between the indoor heat exchanger 6 and the indoor expansion valve 5b, between the indoor expansion valve 5b and the liquid-side check valve 19, and between the indoor heat exchanger 6 and the gas-side check valve 18. In Fig. 3, the second refrigerant piping assembly 10b is connected to these sections, but in cases where vibration or strength of the indoor unit 200 is a problem, the first refrigerant piping assembly 10a may be connected to these sections.

[0102] In addition, in the refrigerant circuit 10, it is preferable that the length along the center line of the first copper tube 13, the length along the center line of the second copper tube 14, the pipe wall thickness of the iron-based first refrigerant pipe 11, the pipe wall thickness of the iron-based second refrigerant pipe 12, the pipe wall thickness of the first copper tube 13, the pipe wall thickness of the second copper tube 14, and the type of compressor 2 are configured in the same way as in the air conditioner 1 described above.

[0103] According to such an air conditioner 3, the refrigerant circuit 10 is formed using the refrigerant piping assemblies 10a, 10b and the four-way valve assembly 10d, so that the copper pipes are joined to the iron-based refrigerant pipes and the iron-based four-way valve in advance by furnace brazing in a controlled atmosphere, and then the ends of the copper pipes joined to the iron-based refrigerant pipes and the iron-based four-way valve can be connected to existing copper-based refrigerant pipes and equipment in any atmosphere such as air. Since a part of the refrigerant circuit 10 is replaced with iron-based refrigerant pipes and equipment, it is possible to connect to existing copper-based refrigerant pipes and equipment using conventional equipment and methods, while reducing material costs. Therefore, despite the presence of joints between dissimilar metals, the iron-based refrigerant pipes and equipment are appropriately joined to the copper-based refrigerant pipes and equipment, and a refrigeration cycle device with reduced manufacturing costs can be provided.

[0104] In addition, the refrigerant pipe assemblies 10a, 10b and the four-way valve assembly 10d use different chemical compositions for the copper-based refrigerant pipes that make up the ends depending on the positional relationship with the equipment that generates vibration, thereby improving the resistance of the refrigerant pipes to vibration. The tensile strength and fatigue strength of the copper pipes connected to the compressor 2 and the four-way valve 3, which generate vibration during operation, are strengthened by solid solution strengthening and precipitation strengthening through the addition of alloy elements. On the other hand, the cost of the copper pipes not connected to these is reduced by not adding alloy elements or by reducing them. Therefore, it is possible to provide a refrigeration cycle device with high resistance to vibration of the refrigerant pipes, which is suppressed in falling off and breaking, and which can be manufactured at reduced costs.

[0105] <Fourth embodiment> Fig. 4 is a diagram showing a refrigerant circuit provided in a refrigeration cycle apparatus according to a fourth embodiment of the present invention. Fig. 4 shows an example of a refrigerant circuit provided in an air conditioner, which is an example of a refrigeration cycle apparatus. As shown in Fig. 4, the air conditioner 4 can also be provided in a configuration that does not include an oil separator. Other main configurations of the air conditioner 4 are similar to those of the air conditioner 1 described above.

[0106] 4, the refrigerant circuit 10 is formed by connecting, via refrigerant piping, a compressor 2, a four-way valve 3, an outdoor heat exchanger 4 which is a heat source side heat exchanger, an outdoor expansion valve 5a which is a pressure reducer, an indoor expansion valve 5b, an indoor heat exchanger 6 which is a utilization side heat exchanger, an accumulator 7, a gas side check valve 18, and a liquid side check valve 19. The refrigerant circuit 10 is made up of at least a gas side refrigerant circuit 10A, a liquid side refrigerant circuit 10B, and a utilization side refrigerant circuit 10C.

[0107] As shown in FIG. 4, the first refrigerant piping assembly 10a is a gas side refrigerant circuit 10A, and can be connected to one or more sections between the accumulator 7 and the compressor 2, between the compressor 2 and the four-way valve 3, between the four-way valve 3 and the gas side stop valve 18, between the four-way valve 3 and the accumulator 7, and between the four-way valve 3 and the outdoor heat exchanger 4.

[0108] That is, the iron-based first refrigerant piping 11, which is an iron-based first metal member, can be disposed between the accumulator 7 and the compressor 2, between the compressor 2 and the four-way valve 3, between the four-way valve 3 and the gas side check valve 18, between the four-way valve 3 and the accumulator 7, or between the four-way valve 3 and the outdoor heat exchanger 4 by incorporating the first refrigerant piping assembly 10a. The first copper tube 13 is joined in advance to an end of such iron-based first refrigerant piping 11. With respect to the outdoor heat exchanger 4, the first copper tube 13 can be connected to the four-way valve 3 side of the header pipe 4b, or the like.

[0109] On the other hand, the second refrigerant piping assembly 10b is a liquid side refrigerant circuit 10B, and can be connected to one or more sections between the outdoor heat exchanger 4 and the outdoor expansion valve 5a, and between the outdoor expansion valve 5a and the liquid side stop valve 19.

[0110] That is, the iron-based second refrigerant piping 12, which is an iron-based second metal member, can be disposed between the outdoor heat exchanger 4 and the outdoor expansion valve 5a, or between the outdoor expansion valve 5a and the liquid side check valve 19, by incorporating the second refrigerant piping assembly 10b. The second copper tube 14 is joined in advance to an end of such iron-based second refrigerant piping 12. With respect to the outdoor heat exchanger 4, the second copper tube 14 can be connected to the distributor 4c side of the main body 4a, the main body 4a side of the distributor 4c, the outdoor expansion valve 5a side, or the like.

[0111] Furthermore, the first refrigerant piping assembly 10a and the second refrigerant piping assembly 10b can also be connected to one or more sections of the user-side refrigerant circuit 10C between the indoor heat exchanger 6 and the indoor expansion valve 5b, between the indoor expansion valve 5b and the liquid-side check valve 19, and between the indoor heat exchanger 6 and the gas-side check valve 18. In Fig. 4, the second refrigerant piping assembly 10b is connected to these sections, but in cases where vibration or strength of the indoor unit 200 is a problem, the first refrigerant piping assembly 10a may be connected to these sections.

[0112] In addition, in the refrigerant circuit 10, it is preferable that the length along the center line of the first copper tube 13, the length along the center line of the second copper tube 14, the pipe wall thickness of the iron-based first refrigerant pipe 11, the pipe wall thickness of the iron-based second refrigerant pipe 12, the pipe wall thickness of the first copper tube 13, the pipe wall thickness of the second copper tube 14, and the type of compressor 2 are configured in the same way as in the air conditioner 1 described above.

[0113] According to such an air conditioner 4, the refrigerant circuit 10 is formed using the refrigerant piping assemblies 10a, 10b, so that the copper pipe and the iron-based refrigerant pipe are previously joined by furnace brazing in a controlled atmosphere, and then the end of the copper pipe joined to the iron-based refrigerant pipe can be connected to existing copper-based refrigerant pipes and equipment in any atmosphere such as air. Since a part of the refrigerant circuit 10 is replaced with an iron-based refrigerant pipe, it is possible to connect to existing copper-based refrigerant pipes and equipment using conventional equipment and methods, while reducing material costs. Therefore, despite the presence of joints between dissimilar metals, the iron-based refrigerant pipes and equipment are appropriately joined to the copper-based refrigerant pipes and equipment, and a refrigeration cycle device with reduced manufacturing costs can be provided.

[0114] Furthermore, the refrigerant pipe assemblies 10a, 10b use different chemical compositions for the copper-based refrigerant pipes that make up the ends depending on the positional relationship with the equipment that generates vibration, thereby improving the resistance of the refrigerant pipes to vibration. The tensile strength and fatigue strength of the copper pipes connected to the compressor 2 and four-way valve 3, which generate vibration during operation, are strengthened by solid solution strengthening and precipitation strengthening through the addition of alloy elements. On the other hand, the cost of the copper pipes not connected to these is reduced by not adding alloy elements or by reducing them. Thus, a refrigeration cycle device can be provided in which the refrigerant pipes have high resistance to vibration, the refrigerant pipes are prevented from falling off or breaking, and manufacturing costs are reduced.

[0115] <Fifth embodiment> Fig. 5 is a diagram showing a refrigerant circuit provided in a refrigeration cycle apparatus according to a fifth embodiment of the present invention. Fig. 5 shows an example of a refrigerant circuit provided in an air conditioner, which is an example of a refrigeration cycle apparatus. As shown in Fig. 5, the air conditioner 5 can also be configured without the second refrigerant piping assembly 10b. Other major components of the air conditioner 5 are similar to those of the air conditioner 1 described above.

[0116] 5, the refrigerant circuit 10 is formed by connecting, via refrigerant piping, a compressor 2, a four-way valve 3, an outdoor heat exchanger 4 which is a heat source side heat exchanger, an outdoor expansion valve 5a which is a pressure reducer, an indoor expansion valve 5b, an indoor heat exchanger 6 which is a utilization side heat exchanger, an accumulator 7, an oil separator 8, a gas side stop valve 18, and a liquid side stop valve 19. The refrigerant circuit 10 is made up of at least a gas side refrigerant circuit 10A, a liquid side refrigerant circuit 10B, and a utilization side refrigerant circuit 10C.

[0117] As shown in FIG. 5, the first refrigerant piping assembly 10a is a gas side refrigerant circuit 10A, and can be connected to one or more sections between the accumulator 7 and the compressor 2, between the compressor 2 and the oil separator 8, between the oil separator 8 and the four-way valve 3, between the four-way valve 3 and the gas side stop valve 18, between the four-way valve 3 and the accumulator 7, and between the four-way valve 3 and the outdoor heat exchanger 4.

[0118] That is, the iron-based first refrigerant piping 11, which is an iron-based first metal member, can be disposed between the accumulator 7 and the compressor 2, between the compressor 2 and the oil separator 8, between the oil separator 8 and the four-way valve 3, between the four-way valve 3 and the gas side check valve 18, between the four-way valve 3 and the accumulator 7, or between the four-way valve 3 and the outdoor heat exchanger 4 by incorporating the first refrigerant piping assembly 10a. The first copper tube 13 is joined in advance to an end of such iron-based first refrigerant piping 11. With respect to the outdoor heat exchanger 4, the first copper tube 13 can be connected to the four-way valve 3 side of the header pipe 4b, or the like.

[0119] On the other hand, the second refrigerant piping assembly 10b is not connected between the outdoor heat exchanger 4 and the outdoor expansion valve 5a, and between the outdoor expansion valve 5a and the liquid side check valve 19, but copper-based refrigerant piping 15 made of copper or a copper alloy is connected. In Fig. 5, copper members 20 are joined to each device, but the copper members 20 may be omitted.

[0120] That is, between the outdoor heat exchanger 4 and the outdoor expansion valve 5a, and between the outdoor expansion valve 5a and the liquid-side stop valve 19, an iron-based second refrigerant pipe 12 is not arranged by assembly of the assembly, and a copper-based refrigerant pipe 15 formed of copper that does not substantially contain alloy elements of one or more of Co, Sn, Zn, Ni, Zr, and Fe by positive addition, or a copper-based refrigerant pipe 15 formed of a copper alloy in which the content rate of these alloy elements is lower than the content rate in the first copper pipe 13 is connected. The copper-based refrigerant pipe 15 can be connected to the outdoor heat exchanger 4 on the distributor 4c side of the main body 4a, on the main body 4a side of the distributor 4c, on the outdoor expansion valve 5a side, or the like.

[0121] Since these sections mainly allow the liquid refrigerant to flow through, they are sections where the thickness of the refrigerant pipe can be provided relatively thin. Also, these sections are sections that are not close to the compressor 2 that generates continuous vibration during operation or the four-way valve 3 that generates intermittent vibration during switching. Since the outdoor heat exchanger 4 is interposed between the compressor 2 and the four-way valve 3, it is difficult for the vibration during operation of the equipment to reach. For such sections, there is little need to use a refrigerant pipe assembly joined with an iron-based refrigerant pipe that is low in cost, and a phosphor-deoxidized copper pipe that has been conventionally used, a copper alloy pipe with a low alloy composition in which the alloy elements are few and the raw material cost is suppressed, or the like can be used.

[0122] Also, among the sections between the indoor heat exchanger 6 and the indoor expansion valve 5b, between the indoor expansion valve 5b and the liquid-side stop valve 19, and between the indoor heat exchanger 6 and the gas-side stop valve 18, one or more sections can be connected with only the first refrigerant pipe assembly 10a, the second refrigerant pipe assembly 10b, or the copper-based refrigerant pipe 15. In FIG. 5, copper-based refrigerant pipes 15 in which the content rate of alloy elements is lower than the content rate in the first copper pipe 13 are connected to these sections, but when vibration or strength becomes a problem in the indoor unit 200, copper-based refrigerant pipes 15 containing one or more of P, Co, Sn, Zn, Ni, Zr, and Fe can be connected to these sections.

[0123] In addition, in the refrigerant circuit 10, it is preferable that the length along the center line of the first copper tube 13, the pipe wall thickness of the iron-based first refrigerant piping 11, the pipe wall thickness of the first copper tube 13, and the type of compressor 2 are configured in the same manner as in the above-mentioned air conditioner 1.

[0124] In such an air conditioner 5, the refrigerant circuit 10 is formed using the refrigerant piping assembly 10a, so that the copper pipe and the iron-based refrigerant pipe are previously joined by furnace brazing in a controlled atmosphere, and then the end of the copper pipe joined to the iron-based refrigerant pipe can be connected to existing copper-based refrigerant pipes and equipment in any atmosphere such as air. Since a portion of the refrigerant circuit 10 is replaced with an iron-based refrigerant pipe, it is possible to connect to existing copper-based refrigerant pipes and equipment using conventional equipment and methods, while reducing material costs. Therefore, despite the presence of a joint between dissimilar metals, the iron-based refrigerant pipes and equipment are appropriately joined to the copper-based refrigerant pipes and equipment, and a refrigeration cycle device with reduced manufacturing costs can be provided.

[0125] In addition, the refrigerant piping assembly 10a uses different chemical compositions for the copper-based refrigerant piping that constitutes the end portion depending on the positional relationship with the equipment that generates vibration, thereby increasing the resistance of the refrigerant piping to vibration. The refrigerant piping assembly 10a is used in sections near the compressor 2 and four-way valve 3 that generate vibration during operation, and copper-based refrigerant piping is used in sections away from the compressor 2 and four-way valve 3, so the cost of the refrigerant circuit 10 as a whole can be reduced, including sections where the refrigerant piping is thin. This makes it possible to provide a refrigeration cycle device that has high resistance to vibration in the refrigerant piping and is manufactured at reduced costs by suppressing the refrigerant piping from falling off or breaking.

[0126] Sixth Embodiment Fig. 6 is a diagram showing a refrigerant circuit provided in a refrigeration cycle apparatus according to a sixth embodiment of the present invention. Fig. 6 shows an example of a refrigerant circuit provided in an air conditioner, which is an example of a refrigeration cycle apparatus. As shown in Fig. 6, the air conditioner 6 is provided with an iron-based oil separator 8a made of iron, iron alloy, or stainless steel, and can also be provided in a configuration without providing a second refrigerant piping assembly 10b. Other main components of the air conditioner 6 are similar to those of the air conditioner 2 described above.

[0127] 6, the refrigerant circuit 10 is formed by connecting via refrigerant piping a compressor 2, a four-way valve 3, an outdoor heat exchanger 4 which is a heat source side heat exchanger, an outdoor expansion valve 5a which is a pressure reducer, an indoor expansion valve 5b, an indoor heat exchanger 6 which is a user side heat exchanger, an accumulator 7, an iron-based oil separator 8a, a gas side stop valve 18, and a liquid side stop valve 19. The refrigerant circuit 10 is made up of at least a gas side refrigerant circuit 10A, a liquid side refrigerant circuit 10B, and a user side refrigerant circuit 10C.

[0128] 6, the oil separator assembly 10c is a gas side refrigerant circuit 10A, and can be connected between the compressor 2 and the four-way valve 3. That is, an iron-based oil separator 8a constituting an iron-based first metal member can be disposed between the compressor 2 and the four-way valve 3 by incorporating the oil separator assembly 10c. A copper-based first refrigerant pipe 13 is joined in advance to the connection portion of the iron-based oil separator 8a.

[0129] In addition, the first refrigerant piping assembly 10a is a gas side refrigerant circuit 10A, and can be connected to one or more sections between the accumulator 7 and the compressor 2, between the four-way valve 3 and the gas side stop valve 18, between the four-way valve 3 and the accumulator 7, and between the four-way valve 3 and the outdoor heat exchanger 4.

[0130] That is, the iron-based first refrigerant piping 11, which is an iron-based first metal member, can be disposed between the accumulator 7 and the compressor 2, between the four-way valve 3 and the gas side check valve 18, between the four-way valve 3 and the accumulator 7, or between the four-way valve 3 and the outdoor heat exchanger 4 by incorporating the first refrigerant piping assembly 10a. The first copper tube 13 is joined in advance to an end of such iron-based first refrigerant piping 11. With respect to the outdoor heat exchanger 4, the first copper tube 13 can be connected to the four-way valve 3 side of the header pipe 4b, etc.

[0131] On the other hand, the second refrigerant piping assembly 10b is not connected between the outdoor heat exchanger 4 and the outdoor expansion valve 5a, and between the outdoor expansion valve 5a and the liquid side check valve 19, but copper-based refrigerant piping 15 made of copper or a copper alloy is connected. In Fig. 6, copper members 20 are joined to each device, but the copper members 20 may be omitted.

[0132] That is, between the outdoor heat exchanger 4 and the outdoor expansion valve 5a, and between the outdoor expansion valve 5a and the liquid side check valve 19, the iron-based second refrigerant piping 12 is not arranged by incorporating an assembly, but a copper-based refrigerant piping 15 made of copper that is substantially free of one or more alloy elements selected from Co, Sn, Zn, Ni, Zr, and Fe by actively adding them, or a copper-based refrigerant piping 15 made of a copper alloy in which the content of these alloy elements is lower than that of the first copper tube 13, is connected. The copper-based refrigerant piping 15 can be connected to the distributor 4c side of the main body 4a, the main body 4a side of the distributor 4c, the outdoor expansion valve 5a side, or the like, of the outdoor heat exchanger 4.

[0133] These sections are sections where the refrigerant piping can be made relatively thin because liquid refrigerant mainly flows through them. Moreover, these sections are not close to the compressor 2, which generates continuous vibrations during operation, or the four-way valve 3, which generates intermittent vibrations during switching. Since the outdoor heat exchanger 4 is interposed between the compressor 2 and the four-way valve 3, the vibrations during operation of the equipment are unlikely to reach these sections. For such sections, there is little need to use a refrigerant piping assembly in which low-cost iron-based refrigerant piping is joined, and it is possible to use conventionally used phosphorus-deoxidized copper pipes, copper alloy pipes with low alloy composition that contain few alloy elements and thus keeps raw material costs down, and the like.

[0134] Also, only the first refrigerant piping assembly 10a, the second refrigerant piping assembly 10b, or the copper-based refrigerant piping 15 may be connected to one or more of the sections between the indoor heat exchanger 6 and the indoor expansion valve 5b, between the indoor expansion valve 5b and the liquid side check valve 19, and between the indoor heat exchanger 6 and the gas side check valve 18. In FIG. 6, copper-based refrigerant piping 15 having a lower content of alloy elements than the content in the first copper tube 13 is connected to these sections, but in cases where vibration or strength is a problem in the indoor unit 200, copper-based refrigerant piping 15 containing one or more alloy elements selected from P, Co, Sn, Zn, Ni, Zr, and Fe may be connected to these sections.

[0135] In addition, in the refrigerant circuit 10, it is preferable that the length along the center line of the first copper tube 13, the pipe wall thickness of the iron-based first refrigerant piping 11, the pipe wall thickness of the first copper tube 13, and the type of compressor 2 are configured in the same manner as in the above-mentioned air conditioner 1.

[0136] According to such an air conditioner 6, the refrigerant circuit 10 is formed using the refrigerant piping assembly 10a and the oil separator assembly 10c, so that the copper pipe and the iron-based refrigerant pipe or the iron-based oil separator are previously joined by furnace brazing in a controlled atmosphere, and then the end of the copper pipe joined to the iron-based refrigerant pipe or the iron-based oil separator can be connected to existing copper-based refrigerant pipes or equipment in any atmosphere such as air. Since a part of the refrigerant circuit 10 is replaced with an iron-based refrigerant pipe or equipment, it is possible to connect to existing copper-based refrigerant pipes and equipment using conventional equipment and methods, while reducing material costs. Therefore, despite the presence of a joint between dissimilar metals, the iron-based refrigerant pipes and equipment are appropriately joined to the copper-based refrigerant pipes and equipment, and a refrigeration cycle device with reduced manufacturing costs can be provided.

[0137] In addition, the refrigerant pipe assembly 10a and the oil separator assembly 10c use different chemical compositions for the copper-based refrigerant pipes that make up the ends depending on the positional relationship with the equipment that generates vibration, which increases the resistance of the refrigerant pipes to vibration. The refrigerant pipe assembly 10a is used in sections near the compressor 2 and four-way valve 3 that generate vibration during operation, and copper-based refrigerant pipes are used in sections away from the compressor 2 and four-way valve 3, so the cost of the refrigerant circuit 10 as a whole can be reduced, including sections where the refrigerant pipes are thin. This makes it possible to provide a refrigeration cycle device that has high resistance to vibration in the refrigerant pipes and is manufactured at reduced costs by suppressing the refrigerant pipes from falling off or breaking.

[0138] Seventh embodiment Fig. 7 is a diagram showing a refrigerant circuit provided in a refrigeration cycle apparatus according to a seventh embodiment of the present invention. Fig. 7 shows an example of a refrigerant circuit provided in an air conditioner, which is an example of a refrigeration cycle apparatus. As shown in Fig. 7, the air conditioner 7 is provided with an iron-based four-way valve 3a made of iron, iron alloy, or stainless steel, and can also be provided in a configuration without a second refrigerant piping assembly 10b. Other main components of the air conditioner 7 are similar to those of the air conditioner 3 described above.

[0139] 7, the refrigerant circuit 10 is formed by connecting, via refrigerant piping, a compressor 2, an iron-based four-way valve 3, an outdoor heat exchanger 4 which is a heat source-side heat exchanger, an outdoor expansion valve 5a which is a pressure reducer, an indoor expansion valve 5b, an indoor heat exchanger 6 which is a user-side heat exchanger, an accumulator 7, an oil separator 8, a gas-side stop valve 18, and a liquid-side stop valve 19. The refrigerant circuit 10 is made up of at least a gas-side refrigerant circuit 10A, a liquid-side refrigerant circuit 10B, and a user-side refrigerant circuit 10C.

[0140] 7, the four-way valve assembly 10d is a gas side refrigerant circuit 10A, and can be connected to the oil separator 8, the gas side stop valve 18, the accumulator 7, and the outdoor heat exchanger 4. That is, the iron-based four-way valve 3a constituting the iron-based first metal member can be disposed in relation to the oil separator 8, the gas side stop valve 18, the accumulator 7, and the outdoor heat exchanger 4 by incorporating the four-way valve assembly 10d. The first copper pipe 13 is joined in advance to the connection portion of the iron-based four-way valve 3a.

[0141] The first refrigerant piping assembly 10a is a gas side refrigerant circuit 10A, and can be connected to one or more sections between the accumulator 7 and the compressor 2 and between the compressor 2 and the oil separator 8.

[0142] That is, the iron-based first refrigerant piping 11, which is an iron-based first metal member, can be disposed between the accumulator 7 and the compressor 2, or between the compressor 2 and the oil separator 8, by incorporating the first refrigerant piping assembly 10a. The first copper tube 13 is joined in advance to an end of such iron-based first refrigerant piping 11. With respect to the outdoor heat exchanger 4, the first copper tube 13 can be connected to the four-way valve 3 side of the header pipe 4b, or the like.

[0143] On the other hand, the second refrigerant piping assembly 10b is not connected between the outdoor heat exchanger 4 and the outdoor expansion valve 5a, and between the outdoor expansion valve 5a and the liquid side check valve 19, but copper-based refrigerant piping 15 made of copper or a copper alloy is connected. In Fig. 7, copper members 20 are joined to each device, but the copper members 20 may be omitted.

[0144] That is, between the outdoor heat exchanger 4 and the outdoor expansion valve 5a, and between the outdoor expansion valve 5a and the liquid side check valve 19, the iron-based second refrigerant piping 12 is not arranged by incorporating an assembly, but a copper-based refrigerant piping 15 made of copper that is substantially free of one or more alloy elements selected from Co, Sn, Zn, Ni, Zr, and Fe by actively adding them, or a copper-based refrigerant piping 15 made of a copper alloy in which the content of these alloy elements is lower than that of the first copper tube 13, is connected. The copper-based refrigerant piping 15 can be connected to the distributor 4c side of the main body 4a, the main body 4a side of the distributor 4c, the outdoor expansion valve 5a side, or the like, of the outdoor heat exchanger 4.

[0145] These sections are sections where the refrigerant piping can be made relatively thin because liquid refrigerant mainly flows through them. Moreover, these sections are not close to the compressor 2, which generates continuous vibrations during operation, or the four-way valve 3, which generates intermittent vibrations during switching. Since the outdoor heat exchanger 4 is interposed between the compressor 2 and the four-way valve 3, the vibrations during operation of the equipment are unlikely to reach these sections. For such sections, there is little need to use a refrigerant piping assembly in which low-cost iron-based refrigerant piping is joined, and it is possible to use conventionally used phosphorus-deoxidized copper pipes, copper alloy pipes with low alloy composition that contain few alloy elements and thus keeps raw material costs down, and the like.

[0146] Also, only the first refrigerant piping assembly 10a, the second refrigerant piping assembly 10b, or the copper-based refrigerant piping 15 may be connected to one or more of the sections between the indoor heat exchanger 6 and the indoor expansion valve 5b, between the indoor expansion valve 5b and the liquid side check valve 19, and between the indoor heat exchanger 6 and the gas side check valve 18. In FIG. 7, copper-based refrigerant piping 15 having a lower content of alloy elements than the content in the first copper tube 13 is connected to these sections, but in cases where vibration or strength is a problem in the indoor unit 200, copper-based refrigerant piping 15 containing one or more alloy elements selected from P, Co, Sn, Zn, Ni, Zr, and Fe may be connected to these sections.

[0147] In addition, in the refrigerant circuit 10, it is preferable that the length along the center line of the first copper tube 13, the pipe wall thickness of the iron-based first refrigerant piping 11, the pipe wall thickness of the first copper tube 13, and the type of compressor 2 are configured in the same manner as in the above-mentioned air conditioner 1.

[0148] According to such an air conditioner 7, the refrigerant circuit 10 is formed using the refrigerant piping assembly 10a and the four-way valve assembly 10d, so that the copper pipes are joined to the iron-based refrigerant pipes and the iron-based four-way valve in advance by brazing in a furnace in a controlled atmosphere, and then the ends of the copper pipes joined to the iron-based refrigerant pipes and the iron-based four-way valve can be connected to existing copper-based refrigerant pipes and equipment in any atmosphere such as air. Since a part of the refrigerant circuit 10 is replaced with iron-based refrigerant pipes and equipment, it is possible to connect to existing copper-based refrigerant pipes and equipment using conventional equipment and methods, while reducing material costs. Therefore, despite the presence of joints between dissimilar metals, the iron-based refrigerant pipes and equipment are appropriately joined to the copper-based refrigerant pipes and equipment, and a refrigeration cycle device with reduced manufacturing costs can be provided.

[0149] In addition, the refrigerant piping assembly 10a and the four-way valve assembly 10d use different chemical compositions for the copper-based refrigerant piping that constitutes the ends depending on the positional relationship with the equipment that generates vibration, thereby increasing the resistance of the refrigerant piping to vibration. The refrigerant piping assembly 10a is used in sections near the compressor 2 and the four-way valve 3 that generate vibration during operation, and copper-based refrigerant piping is used in sections away from the compressor 2 and the four-way valve 3, so the cost of the refrigerant circuit 10 as a whole can be reduced, including sections where the refrigerant piping is thin. This makes it possible to provide a refrigeration cycle device that has high resistance to vibration in the refrigerant piping and is manufactured at reduced costs by suppressing the refrigerant piping from falling off or breaking.

[0150] Eighth embodiment Fig. 8 is a diagram showing a refrigerant circuit provided in a refrigeration cycle apparatus according to an eighth embodiment of the present invention. Fig. 8 shows an example of a refrigerant circuit provided in an air conditioner, which is an example of a refrigeration cycle apparatus. As shown in Fig. 8, the air conditioner 8 can also be provided in a configuration that does not include an oil separator and a second refrigerant piping assembly 10b. Other major components of the air conditioner 8 are similar to those of the air conditioner 4 described above.

[0151] 8, a refrigerant circuit 10 is formed by connecting, via refrigerant piping, a compressor 2, a four-way valve 3, an outdoor heat exchanger 4 which is a heat source side heat exchanger, an outdoor expansion valve 5a which is a pressure reducer, an indoor expansion valve 5b, an indoor heat exchanger 6 which is a utilization side heat exchanger, an accumulator 7, an oil separator 8, a gas side stop valve 18, and a liquid side stop valve 19. The refrigerant circuit 10 is made up of at least a gas side refrigerant circuit 10A, a liquid side refrigerant circuit 10B, and a utilization side refrigerant circuit 10C.

[0152] As shown in FIG. 8, the first refrigerant piping assembly 10a is a gas side refrigerant circuit 10A, and can be connected to one or more sections between the accumulator 7 and the compressor 2, between the compressor 2 and the four-way valve 3, between the four-way valve 3 and the gas side stop valve 18, between the four-way valve 3 and the accumulator 7, and between the four-way valve 3 and the outdoor heat exchanger 4.

[0153] That is, the iron-based first refrigerant piping 11, which is an iron-based first metal member, can be disposed between the accumulator 7 and the compressor 2, between the compressor 2 and the four-way valve 3, between the four-way valve 3 and the gas side check valve 18, between the four-way valve 3 and the accumulator 7, or between the four-way valve 3 and the outdoor heat exchanger 4 by incorporating the first refrigerant piping assembly 10a. The first copper tube 13 is joined in advance to an end of such iron-based first refrigerant piping 11. With respect to the outdoor heat exchanger 4, the first copper tube 13 can be connected to the four-way valve 3 side of the header pipe 4b, or the like.

[0154] On the other hand, the second refrigerant piping assembly 10b is not connected between the outdoor heat exchanger 4 and the outdoor expansion valve 5a, and between the outdoor expansion valve 5a and the liquid side check valve 19, but copper-based refrigerant piping 15 made of copper or a copper alloy is connected. In Fig. 8, copper members 20 are joined to each device, but the copper members 20 may be omitted.

[0155] That is, between the outdoor heat exchanger 4 and the outdoor expansion valve 5a, and between the outdoor expansion valve 5a and the liquid side check valve 19, the iron-based second refrigerant piping 12 is not arranged by incorporating an assembly, but a copper-based refrigerant piping 15 made of copper that is substantially free of one or more alloy elements selected from Co, Sn, Zn, Ni, Zr, and Fe by actively adding them, or a copper-based refrigerant piping 15 made of a copper alloy in which the content of these alloy elements is lower than that of the first copper tube 13, is connected. The copper-based refrigerant piping 15 can be connected to the distributor 4c side of the main body 4a, the main body 4a side of the distributor 4c, the outdoor expansion valve 5a side, or the like, of the outdoor heat exchanger 4.

[0156] These sections are sections where the refrigerant piping can be made relatively thin because liquid refrigerant mainly flows through them. Moreover, these sections are not close to the compressor 2, which generates continuous vibrations during operation, or the four-way valve 3, which generates intermittent vibrations during switching. Since the outdoor heat exchanger 4 is interposed between the compressor 2 and the four-way valve 3, the vibrations during operation of the equipment are unlikely to reach these sections. For such sections, there is little need to use a refrigerant piping assembly in which low-cost iron-based refrigerant piping is joined, and it is possible to use conventionally used phosphorus-deoxidized copper pipes, copper alloy pipes with low alloy composition that contain few alloy elements and thus keeps raw material costs down, and the like.

[0157] Also, only the first refrigerant piping assembly 10a, the second refrigerant piping assembly 10b, or the copper-based refrigerant piping 15 may be connected to one or more of the sections between the indoor heat exchanger 6 and the indoor expansion valve 5b, between the indoor expansion valve 5b and the liquid side check valve 19, and between the indoor heat exchanger 6 and the gas side check valve 18. In FIG. 8, copper-based refrigerant piping 15 having a lower content of alloy elements than the content in the first copper tube 13 is connected to these sections, but in cases where vibration or strength is a problem in the indoor unit 200, copper-based refrigerant piping 15 containing one or more alloy elements selected from P, Co, Sn, Zn, Ni, Zr, and Fe may be connected to these sections.

[0158] In addition, in the refrigerant circuit 10, it is preferable that the length along the center line of the first copper tube 13, the pipe wall thickness of the iron-based first refrigerant piping 11, the pipe wall thickness of the first copper tube 13, and the type of compressor 2 are configured in the same manner as in the above-mentioned air conditioner 1.

[0159] In this air conditioner 8, the refrigerant circuit 10 is formed using the refrigerant piping assembly 10a, so that the copper pipe and the iron-based refrigerant pipe are previously joined by furnace brazing in a controlled atmosphere, and then the end of the copper pipe joined to the iron-based refrigerant pipe can be connected to existing copper-based refrigerant pipes and equipment in any atmosphere such as air. Since a portion of the refrigerant circuit 10 is replaced with an iron-based refrigerant pipe, it is possible to connect to existing copper-based refrigerant pipes and equipment using conventional equipment and methods, while reducing material costs. Therefore, despite the presence of a joint between dissimilar metals, the iron-based refrigerant pipes and equipment are appropriately joined to the copper-based refrigerant pipes and equipment, and a refrigeration cycle device with reduced manufacturing costs can be provided.

[0160] In addition, the refrigerant piping assembly 10a uses different chemical compositions for the copper-based refrigerant piping that constitutes the end portion depending on the positional relationship with the equipment that generates vibration, thereby increasing the resistance of the refrigerant piping to vibration. The refrigerant piping assembly 10a is used in sections near the compressor 2 and four-way valve 3 that generate vibration during operation, and copper-based refrigerant piping is used in sections away from the compressor 2 and four-way valve 3, so the cost of the refrigerant circuit 10 as a whole can be reduced, including sections where the refrigerant piping is thin. This makes it possible to provide a refrigeration cycle device that has high resistance to vibration in the refrigerant piping and is manufactured at reduced costs by suppressing the refrigerant piping from falling off or breaking.

[0161] Next, the results of bending fatigue measurement of a copper pipe joined to a metal member by the bending fatigue test method defined in JIS Z 2273 are shown.

[0162] Fig. 9 is an SN diagram showing the results of a bending fatigue test. The SN diagram in Fig. 9 shows the number of repetitions required to apply a predetermined repeated stress to a copper tube and destroy the copper tube due to the repeated stress. The outer diameter, wall thickness, and length of each pipe in the following Examples 1 and 2 and Comparative Examples 1 and 2 are all the same.

[0163] The copper tube of Example 1 is made of a copper alloy having a material code of C5010T-O and is heated at a temperature equivalent to that for furnace brazing. For example, the copper tube of Example 1 is heated for 20 to 30 minutes in a furnace with an internal temperature of 1000°C to 1100°C.

[0164] The copper tube of Example 2 was made of a copper alloy having a material code of C1862T-O and was heated under the same conditions as those of Example 1.

[0165] The copper tube of Comparative Example 1 is made of standard copper with the material code C1220T-O. The copper tube of Comparative Example 2 is made of standard copper with the material code C1220T-O and heated under the same conditions as those of Examples 1 and 2.

[0166] As shown in FIG. 9, the copper tubes of Examples 1 and 2 have a repetition rate of 1.0×10 n Even in the case of 1000 times, the stress at the time of fracture is higher than the allowable stress σ1. Therefore, it was found that the copper tubes of Examples 1 and 2 have no strength problems even when heated by furnace brazing.

[0167] It was also found that the copper tubes of Examples 1 and 2 showed a smaller decrease in strength with increasing number of cycles than the copper tubes of Comparative Examples 1 and 2. n In the experiment, it was found that the strength of the copper tube of Example 1 was close to that of the copper tube of Comparative Example 2 that was not heated.

[0168] Next, an example of the structure of a joint between an iron-based refrigerant pipe and a copper pipe that form a refrigerant pipe assembly will be described.

[0169] Fig. 10 is a diagram showing an example of a joint between an iron-based refrigerant pipe and a copper pipe. Fig. 10 shows the structure of a joint in which an end of an iron-based refrigerant pipe 11, which is a metal member, and an end of a copper member 20, which is different from the first metal member and the second metal member, are connected via a first copper pipe 13. Examples of the copper member 20 include an end of a copper-based refrigerant pipe that forms the refrigerant circuit 10, and an end of a connection part of a device that executes a refrigeration cycle.

[0170] As shown in Fig. 10, an iron-based first refrigerant pipe 11, which is an iron-based first metal member, can be connected to a copper member 20 forming a refrigerant circuit 10 via a first copper tube 13. The copper member 20 is made of copper that is substantially free of one or more alloy elements selected from Co, Sn, Zn, Ni, Zr, and Fe through active addition, or a copper alloy in which the content of these alloy elements is lower than the content of the first copper tube 13. For example, a phosphorus-deoxidized copper tube that has been conventionally used, or a copper alloy tube with a low alloy composition that contains fewer alloy elements and reduces raw material costs can be used.

[0171] The end of the iron-based refrigerant pipe 11 is preferably provided with an expanded diameter portion 11a having an inner diameter and an outer diameter larger than those of the main body. The end of the first copper pipe 13 is preferably provided with an inner flange 13a protruding in a flange shape toward the center. The length of the first copper pipe 13 along the center line is preferably set shorter than the lengths of the iron-based first refrigerant pipe 11 and the copper member 20 along the center line.

[0172] The outer diameter of the first copper tube 13 is preferably smaller than the inner diameter of the enlarged diameter portion 11a of the iron-based refrigerant pipe 11. The inner diameter of the first copper tube 13 is preferably larger than the outer diameter of the copper member 20. By using such a first copper tube 13, the first copper tube 13 can be fitted inside the enlarged diameter portion 11a of the iron-based refrigerant pipe 11. Furthermore, the end of the copper member 20 can be fitted inside the first copper tube 13.

[0173] The iron-based first refrigerant pipe 11 and the copper member 20 are preferably connected to each other so as to overlap each other via the first copper tube 13. With this structure, even if the length of the first copper tube 13 is shortened, the iron-based first refrigerant pipe 11 and the copper member 20 can be joined with high strength. The iron-based first refrigerant pipe 11 and the first copper tube 13 are brazed in a furnace. The first copper tube 13 joined to the iron-based first refrigerant pipe 11 and the copper member 20 can be joined by air brazing or the like. Since the length of the first copper tube 13 can be shortened, the manufacturing cost of the refrigeration cycle device can be further reduced.

[0174] 10 may also be formed in an iron-based oil separator 8a or an iron-based four-way valve 3a. Such a structure may be formed in some of the joints in the refrigerant circuit 10, or in all of the joints in the refrigerant circuit 10.

[0175] As described above, the embodiments according to the present invention have been explained. However, the present invention is not limited to the above-described embodiments, and various modifications are included as long as the technical scope is not deviated from. For example, the above-described embodiments are not necessarily limited to those having all the configurations described. Also, it is possible to replace a part of the configuration of a certain embodiment with another configuration, or to add another configuration to the configuration of a certain embodiment. Further, it is also possible to add, delete, or replace a configuration for a part of the configuration of a certain embodiment.

[0176] For example, in the above-described embodiment, a receiver, a drier, etc. can also be provided on the refrigerant circuit 10. The receiver, the drier, etc. constitute a metal member to which an assembly can be connected. Also, an injection circuit for injecting refrigerant at an intermediate pressure into the compressor 2 can be provided on the refrigerant circuit 10. The injection circuit bypasses the evaporator from the condenser and is connected to the compressor 2. The injection circuit may be formed by an assembly.

[0177] Also, in the above-described embodiment, an air conditioner is shown as an example of the refrigeration cycle apparatus. However, the air conditioner may be any of a room air conditioner, a package air conditioner, a household multi-air conditioner, a commercial air conditioner, a commercial multi-air conditioner, a building multi-air conditioner, etc. In each figure, the outdoor unit 100 and the indoor unit 200 are connected one-to-one. However, a plurality of outdoor units may be connected to one indoor unit, a plurality of indoor units may be connected to one outdoor unit, or a plurality of indoor units may be connected to a plurality of outdoor units.

[0178] In the above embodiment, an air conditioner is shown as an example of the refrigeration cycle apparatus, but the refrigeration cycle apparatus may be formed as a refrigeration equipment such as a refrigerator, a freezer, a refrigerator, or a refrigerator-freezer. The configuration of the assembly according to the above embodiment can be applied to a refrigeration circuit of a refrigeration equipment having an outdoor unit. The refrigeration circuit of the refrigeration equipment is formed by connecting a compressor, a heat source side heat exchanger arranged outside the cabinet, a pressure reducer such as a capillary, a gas side stop valve, a liquid side stop valve, a user side heat exchanger arranged inside the cabinet, etc., via refrigerant piping.

[0179] In refrigeration equipment, the first metal member may be a three-way valve, an accumulator, an oil separator, a refrigerant pipe forming a gas side refrigerant circuit connecting a gas side stop valve and a heat source side heat exchanger, etc. The second metal member may be a pressure reducer, a refrigerant pipe forming a liquid side refrigerant circuit connecting a heat source side heat exchanger and a liquid side stop valve, etc. [Explanation of symbols]

[0180] 1. Air conditioner 2. Compressor 3. Four-way valve 3a Iron-based four-way valve 4 Outdoor heat exchanger 5a Outdoor expansion valve 5b Indoor expansion valve 6 Indoor heat exchanger 7 Accumulator 8 Oil separator 8a Iron-based oil separator 10 Refrigerant circuit 11 Iron-based No. 1 refrigerant piping 12 Iron-based second refrigerant piping 13 No. 1 copper tube 14 Second copper pipe 15 Copper refrigerant piping 16 Outdoor ventilation fan 17 Indoor ventilation fan 18 Gas side check valve 19 Liquid side check valve 20 Copper parts

Claims

1. An outdoor unit of a refrigeration cycle device including a compressor, a heat source side heat exchanger, a pressure reducer, a gas side check valve, and a liquid side check valve, a first metal member disposed in a gas-side refrigerant circuit that connects the gas-side stop valve and the heat source-side heat exchanger via at least the compressor; a second metal member disposed in a liquid-side refrigerant circuit that connects the heat source-side heat exchanger and the liquid-side check valve via at least the pressure reducer; a first copper tube joined to the first metal member; a second copper tube joined to the second metal member; the first metal member and the second metal member are made of iron, an iron alloy, or stainless steel; The first copper tube is made of a copper alloy containing an alloy element, The second copper tube is made of copper that does not contain the alloy element, or a copper alloy having a lower content of the alloy element than the first copper tube.

2. The outdoor unit of the refrigeration cycle apparatus according to claim 1, the first metal member is a refrigerant pipe, an oil separator, a part of an oil separator, a four-way valve, or a part of a four-way valve; The second metal member is a refrigerant piping of an outdoor unit of a refrigeration cycle device.

3. An outdoor unit of a refrigeration cycle device including a compressor, a heat source side heat exchanger, a pressure reducer, a gas side check valve, and a liquid side check valve, a first metal member disposed in a gas-side refrigerant circuit that connects the gas-side stop valve and the heat source-side heat exchanger via at least the compressor; a refrigerant pipe disposed in a liquid-side refrigerant circuit connecting the heat source-side heat exchanger and the liquid-side check valve via at least the pressure reducer; a first copper tube joined to each of all ends of the first metal member, the first metal member is a refrigerant pipe made of iron, an iron alloy, or stainless steel; The first copper tube is made of a copper alloy containing an alloy element and is connected to a copper member that forms the gas side refrigerant circuit, the refrigerant pipe disposed in the liquid side refrigerant circuit is made of copper not containing the alloy element, or made of a copper alloy having a content rate of the alloy element lower than that of the first copper tube, The outdoor unit of the refrigeration cycle apparatus, wherein the copper member is made of copper that does not contain the alloy element, or a copper alloy in which the content of the alloy element is lower than that of the first copper tube.

4. An outdoor unit of a refrigeration cycle apparatus according to any one of claims 1 to 3, The outdoor unit of the refrigeration cycle device, wherein the alloy element is at least one of P, Co, Sn, Zn, Ni, Zr and Fe.

5. The outdoor unit of the refrigeration cycle apparatus according to claim 1 or 3, The first copper tube is shorter than a refrigerant pipe joined to the first copper tube.

6. The outdoor unit of the refrigeration cycle apparatus according to claim 1 or 3, the first metal member is a refrigerant pipe, An outdoor unit of a refrigeration cycle apparatus, wherein the first copper tube has a thickness greater than a thickness of the refrigerant pipe which is the first metal member.

7. The outdoor unit of the refrigeration cycle apparatus according to claim 1 or 3, the first metal member is a refrigerant pipe, An outdoor unit of a refrigeration cycle apparatus, wherein a thickness of the first copper tube is greater than a thickness of the refrigerant pipe which is the first metal member and a thickness of a refrigerant pipe disposed in the liquid side refrigerant circuit.

8. The outdoor unit of the refrigeration cycle apparatus according to claim 1 or 3, The system includes one or more of an accumulator, an oil separator, and a four-way valve; the first metal member is a refrigerant pipe connected between the compressor and the accumulator, between the compressor and the oil separator, or between the compressor and the four-way valve, The compressor is a scroll compressor or a twin rotary compressor, which is an outdoor unit of a refrigeration cycle device.

9. An outdoor unit of a refrigeration cycle apparatus according to any one of claims 1 to 3, An outdoor unit of a refrigeration cycle apparatus, wherein the content of the alloy element in the first copper tube is lower than the content of the alloy element in the first metal member.

10. The outdoor unit of the refrigeration cycle apparatus according to claim 3, an outdoor unit of a refrigeration cycle apparatus, wherein the refrigerant piping and the copper member overlap with each other via the first copper pipe;

11. A refrigeration cycle apparatus including an outdoor unit having a compressor, a heat source side heat exchanger, a pressure reducer, a gas side check valve, and a liquid side check valve, and an indoor unit, a first metal member disposed in a gas-side refrigerant circuit connecting the gas-side stop valve and the heat source-side heat exchanger via at least the compressor; a second metal member disposed in a liquid-side refrigerant circuit that connects the heat source-side heat exchanger and the liquid-side check valve via at least the pressure reducer, or in a utilization-side refrigerant circuit that is a refrigerant circuit built into the indoor unit; a first copper tube joined to the first metal member; a second copper tube joined to the second metal member; the first metal member and the second metal member are made of iron, an iron alloy, or stainless steel; The first copper tube is made of a copper alloy containing an alloy element, The second copper tube is made of copper that does not contain the alloy element, or a copper alloy having a lower content of the alloy element than the first copper tube.

12. A refrigeration cycle apparatus including an outdoor unit having a compressor, a heat source side heat exchanger, a pressure reducer, a gas side check valve, and a liquid side check valve, and an indoor unit, a first metal member disposed in a gas-side refrigerant circuit connecting the gas-side stop valve and the heat source-side heat exchanger via at least the compressor; a liquid-side refrigerant circuit that connects the heat source-side heat exchanger and the liquid-side check valve via at least the pressure reducer, or a refrigerant pipe that is disposed in a utilization-side refrigerant circuit that is a refrigerant circuit built into the indoor unit; a first copper tube joined to each of all ends of the first metal member, the first metal member is a refrigerant pipe made of iron, an iron alloy, or stainless steel; The first copper tube is made of a copper alloy containing an alloy element and is connected to a copper member that forms the gas side refrigerant circuit, a refrigerant pipe disposed in the liquid side refrigerant circuit or the user side refrigerant circuit is made of copper not containing the alloy element, or is made of a copper alloy having a content rate of the alloy element lower than that of the first copper tube; The copper member is made of copper that does not contain the alloy element, or a copper alloy in which the content of the alloy element is lower than that of the first copper tube.

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