Air conditioner outdoor unit

Abstract

An outdoor unit (1) for an air conditioner comprises: a box-like housing (2) formed from a first metal; a heat exchanger (6) that has at least a portion formed from a second metal having a different spontaneous potential from the first metal, and that is disposed inside the housing (2) and fixed to the housing (2) with a non-conductive member therebetween; and a conductive member (3) formed from non-metal and disposed in the housing (2). The conductive member (3) is fixed to the housing (2) and electrically connected to the housing (2) and is also electrically connected to the heat exchanger (6).

Description

[Technical Field]

[0001] The present disclosure relates to an outdoor unit of an air conditioner that includes a housing and a heat exchanger. [Background technology]

[0002] A conventional outdoor unit of an air conditioner includes a box-shaped housing and a heat exchanger disposed within the housing, the heat exchanger and the housing being made of different metals. The types of metals used for the heat exchanger and the housing are selected based on the required characteristics. For example, aluminum is typically used for the heat exchanger, which requires high thermal conductivity, while iron is typically used for the housing, which requires strength.

[0003] When a heat exchanger and a housing, which are made of dissimilar metals, are in direct contact with each other and moisture adheres to the contact point, galvanic corrosion occurs in the metal with the lower natural potential. Galvanic corrosion is hereinafter referred to simply as corrosion. One known method for preventing corrosion is to indirectly connect the heat exchanger and housing via a non-conductive material such as resin.

[0004] However, when such a means is used, the heat exchanger and the housing are electrically insulated by a non-conductive member, resulting in a parasitic capacitance between them. This creates a problem: Electromagnetic noise generated by electronic boards, compressors, and other components inside the housing causes voltage changes in the parasitic capacitance, which in turn generates further electromagnetic noise. The rear of the housing is provided with an air intake port for introducing outside air, and the heat exchanger is positioned facing the air intake port to exchange heat with the outside air. Electromagnetic noise is radiated from between the heat exchanger and the housing through the air intake port to the outside of the housing.

[0005] To simultaneously solve the two problems of preventing corrosion and reducing electromagnetic noise, Patent Document 1 discloses a technology in which a conductive connecting member is interposed between a heat exchanger and a housing. The connecting member has a first connecting portion made of the same metal as that used in the heat exchanger and in direct contact with the heat exchanger, and a second connecting portion made of the same metal as that used in the housing and in direct contact with the housing. In addition, an insulating layer is provided between the first connecting portion and the second connecting portion to electrically insulate them from each other.

[0006] The technology disclosed in Patent Document 1 ensures electrical continuity and reduces electromagnetic noise by removing part of the insulating layer and bringing the first and second connection parts, which are made of dissimilar metals, into partial direct contact, while covering the contact points between the first and second connection parts with a covering material such as waterproof tape to prevent moisture from penetrating the contact points and prevent corrosion of the metal. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 6583489 Summary of the Invention [Problem to be solved by the invention]

[0008] However, the technology disclosed in Patent Document 1 involves using multiple types of metals for the connecting members, providing an insulating layer, and using a waterproof covering member, which results in a complex structure, resulting in problems such as an increase in manufacturing steps and an increase in the number of parts.

[0009] The present disclosure has been made in consideration of the above, and aims to provide an outdoor unit for an air conditioner that has a simple structure and can achieve both prevention of corrosion and reduction of electromagnetic noise. [Means for solving the problem]

[0010] In order to solve the above-mentioned problems and achieve the object, the outdoor unit of an air conditioner according to the present disclosure is formed from a first metal. , which constitutes the outer shell of the outdoor unit of the air conditioner. The heat exchanger includes a box-shaped housing, a heat exchanger at least a portion of which is made of a second metal having a different natural potential from the first metal and is disposed within the housing and fixed to the housing via a non-conductive member, and a conductive member formed of a non-metal and disposed within the housing. The conductive member is fixed to the housing and electrically connected to the housing, and is also electrically connected to the heat exchanger. [Effects of the Invention]

[0011] The outdoor unit of an air conditioner according to the present disclosure has a simple structure and provides the effect of achieving both prevention of corrosion and reduction of electromagnetic noise. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is an exploded perspective view schematically showing an outdoor unit of an air conditioner according to a first embodiment. [Figure 2] FIG. 1 is a front view showing an outdoor unit of an air conditioner according to a first embodiment, with a front panel of the housing removed; [Figure 3] FIG. 1 is an exploded perspective view showing an electronic board box and an interface panel according to the first embodiment. [Figure 4] FIG. 4 is a perspective view showing the electronic circuit board box and the interface panel shown in FIG. 3 assembled together; [Figure 5] FIG. 1 is a right side view showing an outdoor unit of an air conditioner according to a first embodiment. [Figure 6] Cross-sectional view taken along line VI-VI shown in Figure 2 [Figure 7] FIG. 1 is a perspective view schematically illustrating a heat exchanger according to a first embodiment. [Figure 8] FIG. 1 is a front view showing a heat exchanger according to a first embodiment. [Figure 9] Enlarged view of the main part of the heat exchanger shown in Figure 8 [Figure 10] FIG. 1 is a plan view showing a conductive member according to the first embodiment, illustrating a first conductive member; [Figure 11] FIG. 1 is a plan view showing the conductive member according to the first embodiment, illustrating a second conductive member; [Figure 12] FIG. 1 is a plan view showing an outdoor unit of an air conditioner according to a first embodiment, illustrating a state in which a housing top panel of the housing is removed and a conductive member is attached to the housing; [Figure 13] FIG. 1 is a schematic diagram illustrating a transmission path of electromagnetic noise as an electric circuit in an outdoor unit of an air conditioner according to a first embodiment. [Figure 14] 1 is an equivalent circuit diagram of a path through which a current that causes electromagnetic noise is transmitted when a conductive member is not provided in the outdoor unit of the air conditioner according to the first embodiment. [Figure 15] FIG. 1 is a rear view of the outdoor unit of the air conditioner according to the first embodiment, illustrating a location where electromagnetic noise occurs when no conductive member is provided. [Figure 16] 1 is an equivalent circuit diagram of a path through which a current that causes electromagnetic noise is transmitted when a heat exchanger and a housing are in direct contact without an insulating member in an outdoor unit of an air conditioner according to a first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, an outdoor unit of an air conditioner according to an embodiment will be described in detail with reference to the drawings.

[0014] Embodiment 1 Fig. 1 is an exploded perspective view that schematically shows an outdoor unit 1 of an air conditioner according to embodiment 1. As shown in Fig. 1, the outdoor unit 1 of the air conditioner includes a housing 2, a plurality of conductive members 3, a partition panel 4, a blower 5, a heat exchanger 6, a plurality of insulating members 7, a compressor 8, and an electronic circuit board box 9. Hereinafter, the outdoor unit 1 of the air conditioner may also be simply referred to as the outdoor unit 1.

[0015] Hereinafter, when describing the directions of each component of the outdoor unit 1, the depth direction of the outdoor unit 1 will be referred to as the X-axis direction, the height direction of the outdoor unit 1 as the Y-axis direction, and the width direction of the outdoor unit 1 as the Z-axis direction. The + direction in the X-axis direction will be referred to as the forward direction, and the - direction in the X-axis direction will be referred to as the rearward direction. The + direction in the X-axis direction is the direction from the - side to the + side of the X-axis, and the - direction in the X-axis direction is the direction from the + side to the - side of the X-axis. The + direction in the Y-axis direction is referred to as the upward direction, and the - direction in the Y-axis direction is referred to as the downward direction. The + direction in the Y-axis direction is the direction from the - side to the + side of the Y-axis, and the - direction in the Y-axis direction is the direction from the + side to the - side of the Y-axis. The + direction in the Z-axis direction is referred to as the rightward direction, and the - direction in the Z-axis direction is referred to as the leftward direction. The + direction in the Z-axis direction is the direction from the - side to the + side of the Z-axis, and the - direction in the Z-axis direction is the direction from the + side to the - side of the Z-axis. In this embodiment, the positive direction of the X-axis direction in which the airflow generated by the fan 5 of the outdoor unit 1 is discharged to the outside is the front, and the side opposite the front is the back.

[0016] FIG. 2 is a front view showing the outdoor unit 1 of the air conditioner according to the first embodiment, with the housing front panel 2e of the housing 2 removed. In FIG. 2, the heat exchanger 6 is hatched with dots for ease of understanding. As shown in FIGS. 1 and 2, the housing 2 is a box-shaped member that forms the outer shell of the outdoor unit 1. The housing 2 is made of a first metal. The first metal is preferably a metal with high strength. The first metal is, for example, iron or an iron alloy.

[0017] As shown in FIG. 1, the housing 2 has a housing floor panel 2a, a housing top panel 2b, a first connecting panel 2c, and a second connecting panel 2d. The housing floor panel 2a forms the bottom surface of the outer shell of the outdoor unit 1. The shape of the housing floor panel 2a in a plan view is a rectangle with rounded corners. The housing top panel 2b is disposed above and spaced apart from the housing floor panel 2a. The housing top panel 2b forms the ceiling surface of the outer shell of the outdoor unit 1. The shape of the housing top panel 2b in a plan view is the same as the shape of the housing floor panel 2a in a plan view.

[0018] The first connecting panel 2c and the second connecting panel 2d connect the housing floor panel 2a and the housing top panel 2b. The first connecting panel 2c has an L-shaped planar shape. The first connecting panel 2c has a housing front panel 2e extending along the Z-axis direction and a housing side panel 2f extending rearward from the left edge of the housing front panel 2e, which is one edge along the Z-axis direction.

[0019] The housing front panel 2e connects the front edge of the housing floor panel 2a and the front edge of the housing top panel 2b. The housing front panel 2e forms the front surface of the outer shell of the outdoor unit 1. An exhaust port 2j is formed in the housing front panel 2e. The exhaust port 2j is an opening for discharging the airflow generated by the blower 5 to the outside of the fan chamber 10, which will be described later. The housing side panel 2f connects the left edge of the housing floor panel 2a and the left edge of the housing top panel 2b. The housing side panel 2f forms the left side surface of the outer shell of the outdoor unit 1. In this embodiment, the housing front panel 2e and the housing side panel 2f are formed integrally, but they may also be formed separately.

[0020] The second connecting panel 2d has an L-shaped planar shape. The second connecting panel 2d has a housing side panel 2g extending along the X-axis direction, and a housing back panel 2h extending leftward from a rear edge portion, which is one edge portion of the housing side panel 2g along the X-axis direction.

[0021] The housing side panel 2g connects the right edge of the housing floor panel 2a to the right edge of the housing top panel 2b. The housing side panel 2g forms the right side of the outer shell of the outdoor unit 1. The housing back panel 2h connects part of the rear edge of the housing floor panel 2a to part of the rear edge of the housing top panel 2b. The housing back panel 2h forms part of the back of the outer shell of the outdoor unit 1. In this embodiment, the housing side panel 2g and the housing back panel 2h are formed integrally, but may also be formed separately.

[0022] 1 is assembled, the left edge of the housing rear panel 2h and the rear edge of the housing side panel 2f are spaced apart. An air intake port 2i for letting in outside air is formed between the left edge of the housing rear panel 2h and the rear edge of the housing side panel 2f. The air intake port 2i is an opening for letting air outside the housing 2 into the fan chamber 10, which will be described later. The air intake port 2i is surrounded by the housing floor panel 2a, the housing top panel 2b, the housing rear panel 2h, and the housing side panel 2f.

[0023] The conductive member 3 is a member disposed within the housing 2. The conductive member 3 is formed of a non-metal that is conductive with respect to metals. The conductive member 3 can be made of, for example, a composite material in which a conductor such as carbon fiber is kneaded into an insulating plastic, or a composite material in which a thin conductive film is formed on the surface of an insulating plastic. Examples of such composite materials include carbon graphite. The conductive member 3 is fixed to the housing 2 and electrically connected to the housing 2, and is also electrically connected to the heat exchanger 6. The housing 2 and the heat exchanger 6 are electrically connected via the conductive member 3. In this specification, the "electrical connection" between the metal member and the conductive member 3 includes not only a state in which the metal member and the conductive member 3 are in direct contact and electrically connected, but also a state in which the metal member and the conductive member 3 are electrically connected via a gap. In this embodiment, the conductive member 3 is in contact with the housing 2 and the heat exchanger 6.

[0024] The casing 2 and the conductive members 3 are joined at points where they come into contact with each other by welding, screws, or the like. If the surfaces of the panels of the casing 2 are painted or otherwise coated, resulting in high electrical resistance on the surfaces of the panels, the electrical resistance on the surfaces of the panels can be reduced by, for example, masking part or all of the joints in advance or removing the paint when fastening the screws using serrated screws. The number of conductive members 3 may be one or more, but in this embodiment, there are two. Hereinafter, when distinguishing between the two conductive members 3, one conductive member 3 will be referred to as the first conductive member 3a and the other conductive member 3 will be referred to as the second conductive member 3b.

[0025] As shown in FIG. 2, the partition panel 4 is a metal member that divides the interior of the housing 2 into a fan chamber 10 and an electrical chamber 11. The partition panel 4 is a part of the housing 2. The fan chamber 10 and the electrical chamber 11 are formed side by side in the Z-axis direction. The partition panel 4 extends in the Y-axis direction from the housing floor panel 2a to the electronic circuit board box 9. The partition panel 4 extends in the X-axis direction from the housing front panel 2e to the housing rear panel 2h shown in FIG. 1.

[0026] The housing 2 and the partition panel 4 shown in Fig. 1 are made of the same type of first metal. The housing 2 and the partition panel 4 are joined at the locations where they come into contact with each other by welding, screws, etc. If the surfaces of the panels of the housing 2 are painted or the like and the electrical resistance of the surfaces of the panels is high, the electrical resistance of the surfaces of the panels can be reduced by, for example, masking some or all of the joints in advance or by using serrated screws to remove the paint when fastening the screws.

[0027] As shown in FIG. 2, the blower 5 is disposed in the fan chamber 10 and generates an airflow. The blower 5 includes a support 5a extending from the housing floor panel 2a, a fan motor 5b attached to the support 5a, and a propeller fan 5c attached to the shaft of the fan motor 5b and rotating with the rotation of the fan motor 5b. The upper end of the support 5a is fixed to the housing top panel 2b. The lower end of the support 5a is fixed to the housing floor panel 2a. The fan motor 5b is electrically connected to an electronic board 9c (described later) via a fan drive cable 12. The fan motor 5b rotates when it receives a drive signal output from the electronic board 9c via the fan drive cable 12. When the fan motor 5b rotates and the propeller fan 5c is driven, negative pressure is created in the fan chamber 10, and air outside the outdoor unit 1 flows into the fan chamber 10 through the air intake port 2i. The air that has flowed into the fan chamber 10 passes through the heat exchanger 6, is formed into an air flow by the blower 5, and is discharged to the outside of the fan chamber 10 through the exhaust port 2j shown in FIG.

[0028] The heat exchanger 6 is disposed in the fan chamber 10 and is a component for exchanging heat between the refrigerant and outdoor air. Outdoor air to be taken into the blower 5 passes through the heat exchanger 6. The heat exchanger 6 is, for example, a parallel flow type heat exchanger. The heat exchanger 6 is disposed within the housing 2 and fixed to the housing 2 via an insulating member 7, which is a non-conductive member. At least a portion of the heat exchanger 6 is formed from a second metal having a natural potential different from that of the first metal. The second metal is preferably a metal with high thermal conductivity. The second metal is, for example, aluminum or an aluminum alloy. The natural potential of the first metal is higher than the natural potential of the second metal.

[0029] As shown in FIG. 1, the heat exchanger 6 has an L-shaped planar shape. The heat exchanger 6 has a first heat exchange section 6a extending along the Z-axis direction and a second heat exchange section 6b extending along the X-axis direction. The second heat exchange section 6b extends forward from the left end of the first heat exchange section 6a, which is one end of the first heat exchange section 6a along the Z-axis direction. The first heat exchange section 6a is disposed behind the blower 5. The second heat exchange section 6b is disposed to the left of the blower 5 when viewed from the front of the outdoor unit 1. The heat exchanger 6 and the blower 5 are either disposed at a distance from each other and electrically insulated, or disposed via an insulating member (not shown) and electrically insulated.

[0030] The heat exchanger 6 and the first connecting panel 2c and the second connecting panel 2d are electrically insulated from each other by being spaced apart from each other, or are electrically insulated from each other by being arranged via an insulating member (not shown). As shown in FIG. 2, the upper end of the heat exchanger 6 is fixed to the housing top panel 2b via an insulating member 7. The lower end of the heat exchanger 6 is fixed to the housing floor panel 2a via an insulating member 7. The heat exchanger 6 is electrically insulated from the housing top panel 2b and the housing floor panel 2a. The heat exchanger 6 is arranged without direct contact with metal members such as the housing 2 and the fan 5 arranged around the heat exchanger 6.

[0031] The two insulating members 7 shown in FIG. 1 are made of an electrically insulating material such as resin. Hereinafter, when distinguishing between the two insulating members 7, the insulating member 7 provided at the lower end of the heat exchanger 6 will be referred to as the first insulating member 7a, and the insulating member 7 provided at the upper end of the heat exchanger 6 will be referred to as the second insulating member 7b. In this embodiment, the first insulating member 7a and the second insulating member 7b, which have the same planar shape and size as the heat exchanger 6, are used to cover the entire bottom and top surfaces of the heat exchanger 6, thereby electrically insulating the heat exchanger 6 from the housing 2. However, this is not intended to limit the electrical insulation means between the two members. For example, a configuration may be adopted in which pedestals made of an electrically insulating material are provided at several locations on the bottom surface of the heat exchanger 6, interposing the pedestals between the heat exchanger 6 and the housing floor panel 2a. With this configuration, the heat exchanger 6 and the housing floor panel 2a are spaced apart from each other in the Y-axis direction, so that the heat exchanger 6 and the housing floor panel 2a can be electrically insulated from each other.

[0032] As shown in Fig. 2, compressor 8 is disposed in electrical compartment 11 and is a device that compresses the refrigerant flowing through heat exchanger 6. Compressor 8 is disposed on housing floor panel 2a in the lower space of electrical compartment 11. Compressor 8 is fixed to housing floor panel 2a with screws or the like.

[0033] The electronic board box 9 is a member that houses electronic boards 9c such as control boards required to operate the outdoor unit 1. The electronic board box 9 is formed in the shape of a hollow rectangular parallelepiped. The electronic board box 9 is fixed to the upper end of the partition panel 4 and is arranged straddling the fan chamber 10 and the electrical chamber 11. A heat sink 9d extending downward is attached to the portion of the electronic board box 9 that is arranged in the fan chamber 10. The heat sink 9d is exposed to the fan chamber 10. The heat sink 9d is cooled by the airflow generated by the blower 5.

[0034] The portion of the electronic board box 9 that is arranged in the electric chamber 11 is disposed above the compressor 8. A compressor drive wire 13 is connected to the portion of the electronic board 9c that is arranged in the electric chamber 11. The compressor 8 is electrically connected to the electronic board 9c via the compressor drive wire 13. The compressor 8 is driven when it receives a drive signal output from the electronic board 9c via the compressor drive wire 13.

[0035] The electrical compartment 11 is surrounded by the housing floor panel 2a, the partition panel 4, the housing side panel 2g, the electronic circuit board box 9, and the housing front panel 2e and housing rear panel 2h shown in Figure 1, providing a waterproof structure that prevents the infiltration of rainwater and other moisture from outside the housing 2. A stop valve 17 is provided at the bottom of the outer surface of the housing side panel 2g. The stop valve 17 serves as a terminal for connecting a refrigerant pipe that connects to an indoor unit (not shown).

[0036] The compressor 8 and the stop valve 17 are connected to each other via a plurality of refrigerant pipes 18. The compressor 8 and the heat exchanger 6 are connected to each other via a plurality of refrigerant pipes 18. A connection 19 between the heat exchanger 6 and the refrigerant pipes 18 is disposed in the electrical chamber 11, which has a waterproof structure. Disposing the connection 19 in the electrical chamber 11 in this manner prevents contact between the connection 19 and moisture, thereby preventing corrosion of the connection 19. Note that, to further enhance the waterproof effect of the connection 19, the connection 19 may be waterproofed by wrapping waterproof tape or the like around it. Although not specifically illustrated, the refrigerant pipes 18 are connected to valve devices such as a four-way valve that switches the flow direction of the refrigerant and an expansion valve that expands the refrigerant to a predetermined pressure. The connection configuration of the refrigerant pipes 18 is not limited to the example shown in the figure.

[0037] An interface panel 20 is installed in the upper space of the electrical compartment 11. The interface panel 20 is fixed to the inner surface of the housing side panel 2g and the underside of the electronic board box 9. A terminal block 21 is installed on the interface panel 20. An external AC power line 14 and an internal power line 15 are connected to the terminal block 21. The external AC power line 14 is electrically connected to the internal power line 15 via the terminal block 21. The internal power line 15 is electrically connected to the electronic board 9c. Power is supplied to the electronic board 9c via the external AC power line 14, the terminal block 21, and the internal power line 15. The voltage of the power supplied to the electronic board 9c is, for example, single-phase 200V, but is not limited to this voltage.

[0038] The interface panel 20 is made of the same first metal as the housing side panel 2g. Therefore, the interface panel 20 is joined to the housing side panel 2g with low electrical resistance. The interface panel 20 is connected to the signal ground of the electronic board 9c. The interface panel 20 has an earth connection point 20e to which the earth wire 16 is connected. The interface panel 20 is grounded via the earth connection point 20e and the earth wire 16. The housing 2 joined to the interface panel 20 and the partition panel 4 joined to the housing 2 are grounded via the earth connection point 20e and the earth wire 16.

[0039] Next, the configuration of the outdoor unit 1 will be described in more detail. First, the configurations of the electronic board box 9 and the interface panel 20 will be described with reference to Fig. 3 and Fig. 4. Fig. 3 is an exploded perspective view showing the electronic board box 9 and the interface panel 20 in embodiment 1. Fig. 4 is a perspective view showing the electronic board box 9 and the interface panel 20 shown in Fig. 3 assembled together.

[0040] 3, the electronic circuit board box 9 includes a box-shaped lower box 9a that opens upward, a top cover 9b that covers the top opening of the lower box 9a, an electronic circuit board 9c, and a heat sink 9d. The electronic circuit board 9c is disposed within the lower box 9a and fixed to the lower box 9a. The electronic circuit board 9c includes an internal power line 15 that is connected to the terminal block 21 and a compressor drive wire 13 that is connected to the compressor 8. Although not shown, the electronic circuit board 9c also includes various power lines for operating the heat generating elements, the fan motor 5b, and other driving devices.

[0041] The heat sink 9d is fixed to the electronic substrate 9c in a state where it is in close contact with the electronic substrate 9c. The heat sink 9d serves to cool the heat-generating elements of the electronic substrate 9c. The heat-generating elements are, for example, power semiconductors such as IGBTs (Insulated Gate Bipolar Transistors). The electronic substrate 9c to which the heat sink 9d is fixed is inserted into the lower box 9a through an opening in the top of the lower box 9a. As shown in FIGS. 3 and 4, part or all of the heat sink 9d is exposed to the outside of the lower box 9a through a hole 9e formed in the bottom wall of the lower box 9a.

[0042] The lower box 9a and the upper cover 9b shown in FIG. 3 are formed of, for example, rubber, resin, or a metal such as iron, or a combination of these. For example, if the lower box 9a and the upper cover 9b are formed of metal, the electronic board 9c is covered with metal, which can suppress the radiation of electromagnetic noise generated by the electronic board 9c to the outside of the electronic board box 9. There is a risk that moisture such as rainwater scattered in the fan chamber 10 may enter the electronic board box 9 and the electrical chamber 11 through the hole 9e formed in the bottom wall of the lower box 9a. Therefore, in practice, measures are taken to ensure the waterproofing of the electronic board box 9 and the electrical chamber 11 by modifying the shape of the hole 9e and the shape of the lower box 9a to make it difficult for moisture to enter, or by adding new waterproofing structures.

[0043] The interface panel 20 has an interface vertical wall 20a, an upper joining flange portion 20b, an interface horizontal wall 20c, and a lower joining flange portion 20d. The interface vertical wall 20a is a vertical wall extending along the Y-axis direction. The upper joining flange portion 20b extends horizontally in the Z-axis direction from the upper end of the interface vertical wall 20a. The upper joining flange portion 20b is joined to the lower surface of the bottom wall of the lower box 9a. The interface horizontal wall 20c extends horizontally in the Z-axis direction from the lower end of the interface vertical wall 20a. The lower joining flange portion 20d extends downward in the Y-axis direction from the tip of the interface horizontal wall 20c. The lower joining flange portion 20d is joined to the inner surface of the housing side panel 2g shown in FIG. 2. The interface panel 20 is fixed to the housing side panel 2g at the lower joining flange portion 20d and is electrically connected to the housing side panel 2g. The interface panel 20 is fixed to the housing side panel 2g and the lower box 9a.

[0044] Next, the configuration of the right side of the outdoor unit 1 will be described with reference to Fig. 5. Fig. 5 is a right side view showing the outdoor unit 1 of the air conditioner according to the first embodiment.

[0045] An opening 2k that connects the inside and outside of the housing 2 is formed in the housing side panel 2g. An interface cover 22 is detachably attached to the housing side panel 2g. The interface cover 22 can be opened and closed by attaching and detaching it. When closed, the interface cover 22 covers the opening 2k. When open, the interface cover 22 opens the opening 2k. The interface panel 20 and terminal block 21 installed in the electrical room 11 are visible and accessible through the opening 2k. Wiring of various power lines can be performed by opening the interface cover 22 and passing through the opening 2k.

[0046] The interface cover 22 serves to prevent moisture such as rainwater from entering the electrical chamber 11 while ensuring ventilation between the electrical chamber 11 and the outside of the housing 2. The interface cover 22 is made of resin, a metal such as iron, or a combination of these. When the interface cover 22 is made of a metal such as iron and is joined to the housing side panel 2g in a state where electrical resistance is low, closing the opening 2k with the interface cover 22 can suppress radiation of electromagnetic noise from the opening 2k to the outside of the housing 2.

[0047] Although not shown, a through hole is formed in the interface cover 22 for the purpose of ensuring ventilation between the electrical chamber 11 and the outside of the housing 2 and for allowing power lines to pass between the electrical chamber 11 and the outside of the housing 2. Waterproofing means is provided in the through hole to prevent moisture such as rainwater from entering the electrical chamber 11. Examples of waterproofing means include lining the gaps in the through hole with sponge or making the through hole have a shutter structure.

[0048] Next, the configuration of the partition panel 4 will be described with reference to Fig. 6. Fig. 6 is a cross-sectional view taken along line VI-VI shown in Fig. 2. In Fig. 6, for ease of understanding, only the housing 2 is hatched with diagonal lines.

[0049] The partition panel 4 has a first partition 4a and a second partition 4b connected to the rear end of the first partition 4a. An introduction hole 4c is formed in the second partition 4b to introduce the end of the heat exchanger 6 in the Z-axis direction into the electric chamber 11. The heat exchanger 6 and the second partition 4b are made of dissimilar metals. To prevent contact between the dissimilar metals, it is preferable to interpose a resin material between the heat exchanger 6 and the second partition 4b, for example.

[0050] Next, the configuration of the heat exchanger 6 will be further described with reference to Fig. 7 to Fig. 9. Fig. 7 is a perspective view that schematically shows the heat exchanger 6 in the first embodiment. Fig. 8 is a front view that shows the heat exchanger 6 in the first embodiment. Fig. 9 is an enlarged view of a main part of the heat exchanger 6 shown in Fig. 8.

[0051] As shown in Fig. 7, the heat exchanger 6 in this embodiment is a parallel flow type heat exchanger. As shown in Fig. 8, the heat exchanger 6 has two headers 6c and 6d, a plurality of refrigerant conduits 6e, and a plurality of fins 6f.

[0052] The two headers 6c, 6d are both hollow metal members. Each of the headers 6c, 6d extends along the Y-axis direction. As shown in FIG. 7, the two headers 6c, 6d are spaced apart from each other in the Z-axis direction and are shifted from each other in the X-axis direction. The header 6c is provided at the front end of the second heat exchanger 6b. The header 6d is provided at the right end of the first heat exchanger 6a. A refrigerant pipe 18 is connected to the header 6d.

[0053] Each refrigerant conduit 6e shown in FIG. 8 is a hollow metal member. Each refrigerant conduit 6e is, for example, a flat pipe. The multiple refrigerant conduits 6e are arranged at intervals from one another in the Y-axis direction. Each refrigerant conduit 6e extends from one header 6c to the other header 6d. The extension direction of each refrigerant conduit 6e is perpendicular to the Y-axis direction. One end of each refrigerant conduit 6e in the extension direction is connected to one header 6c, and the other end of each refrigerant conduit 6e in the extension direction is connected to the other header 6d. Each refrigerant conduit 6e communicates between one header 6c and the other header 6d.

[0054] The fins 6f are metal plate-like members. The fins 6f are arranged between adjacent refrigerant conduits 6e. There are no particular limitations on the shape of the fins 6f, but in this embodiment, they have a wave-like shape that protrudes alternately upward and downward. That is, the fins 6f are corrugated fins in this embodiment. As shown in FIG. 9, the fins 6f contact each of the adjacent refrigerant conduits 6e and are joined thereto by welding or the like.

[0055] A refrigerant flows through the headers 6c, 6d and the refrigerant conduit 6e shown in FIG. 8. One of the two headers 6c, 6d distributes the refrigerant to each of the multiple refrigerant conduits 6e. The other of the two headers 6c, 6d joins the refrigerants flowing out of each of the multiple refrigerant conduits 6e. The refrigerant conduit 6e exchanges heat between the refrigerant and outdoor air. That is, heat is exchanged between the refrigerant flowing inside the refrigerant conduit 6e and the outdoor air flowing around the refrigerant conduit 6e. The fins 6f promote heat exchange between the refrigerant and outdoor air.

[0056] Next, the configuration of the conductive member 3 will be further described with reference to FIGS. 10 and 11. FIG. 10 is a plan view showing the conductive member 3 according to the first embodiment, illustrating a first conductive member 3a. FIG. 11 is a plan view showing the conductive member 3 according to the first embodiment, illustrating a second conductive member 3b. FIG. 12 is a plan view showing the outdoor unit 1 of the air conditioner according to the first embodiment, illustrating a state in which the housing top panel 2b of the housing 2 is removed and the conductive member 3 is attached to the housing 2. In FIG. 12, the heat exchanger 6 is shown in direct contact with the partition panel 4 and the housing side panel 2f of the housing 2, but in reality, the heat exchanger 6 is disposed without direct contact with metal members such as the housing 2. In FIG. 12, the heat exchanger 6 is hatched with dots for ease of understanding.

[0057] As shown in FIG. 10, the shape of the first conductive member 3a is not particularly limited, but is L-shaped in this embodiment. The first conductive member 3a has a first plate portion 3c and a second plate portion 3d. The first conductive member 3a shown in FIG. 12 electrically connects the partition panel 4 and the first heat exchanger 6a. The first conductive member 3a is disposed in the fan chamber 10. The first conductive member 3a is disposed in an inner corner formed by the partition panel 4 and the first heat exchanger 6a. The first conductive member 3a is disposed to the left of the partition panel 4. The first conductive member 3a is disposed in front of the first heat exchanger 6a. The first conductive member 3a is fixed to the partition panel 4, which is part of the housing 2, and is electrically connected to the partition panel 4 and the first heat exchanger 6a.

[0058] The first plate portion 3c extends along the X-axis direction. The first plate portion 3c is in contact with a side surface 4d of the partition panel 4 that faces the fan chamber 10. The side surface 4d is a flat surface that extends in the X-axis direction and the Y-axis direction. The first plate portion 3c is fixed to the partition panel 4. The second plate portion 3d extends along the Z-axis direction. The second plate portion 3d extends leftward from a rear end portion, which is one end of the first plate portion 3c along the Z-axis direction. The second plate portion 3d is in contact with a front surface 6g of the first heat exchange portion 6a that faces the fan chamber 10. The front surface 6g is a flat surface that extends in the Z-axis direction and the Y-axis direction.

[0059] As shown in FIG. 11, the shape of the second conductive member 3b is not particularly limited, but in this embodiment, it is crank-shaped. The second conductive member 3b has a fixed portion 3e, a plate portion 3f, and a connecting portion 3g connecting the fixed portion 3e and the plate portion 3f. The second conductive member 3b shown in FIG. 12 electrically connects the housing side panel 2f and the second heat exchanger 6b. The second conductive member 3b is disposed in the fan chamber 10. The second conductive member 3b is disposed in an inner corner formed by the housing side panel 2f and the second heat exchanger 6b. The second conductive member 3b is disposed to the right of the housing side panel 2f. The second conductive member 3b is disposed from the front to the left of the second heat exchanger 6b. The second conductive member 3b is fixed to the housing side panel 2f and electrically connected to the housing side panel 2f and the second heat exchanger 6b.

[0060] The fixing portion 3e extends along the X-axis direction. The fixing portion 3e is in contact with an inner surface 2m of the housing side panel 2f that faces the fan chamber 10. The inner surface 2m is a flat surface that extends in the X-axis direction and the Y-axis direction. The fixing portion 3e is fixed to the housing side panel 2f. The connecting portion 3g extends to the right from the rear end, which is one end of the fixing portion 3e along the X-axis direction. The connecting portion 3g extends along the Z-axis direction. The connecting portion 3g is in contact with a front surface 6h of the second heat exchanger 6b that faces the fan chamber 10. The front surface 6h is a flat surface that extends in the Z-axis direction and the Y-axis direction. The plate portion 3f extends rearward from the right end, which is one end of the connecting portion 3g along the Z-axis direction. The plate portion 3f extends along the X-axis direction. The plate portion 3f is in contact with a side surface 6i of the second heat exchanger 6b that faces the fan chamber 10. The side surface 6i is a flat surface extending in the X-axis direction and the Y-axis direction. The side surface 6i extends rearward from the right end portion of the front surface 6h, which is one end portion along the Z-axis direction, toward the front surface 6g.

[0061] In this embodiment, the conductive member 3 is fixed to the housing side panel 2f or the partition panel 4 and electrically connected to the housing 2, but it may be fixed to at least one of the housing floor panel 2a, the housing top panel 2b, the housing front panel 2e, the housing rear panel 2h, the housing side panels 2f and 2g, and the partition panel 4 and electrically connected to the housing 2. The size of the conductive member 3 is preferably such that the electrical connection between the housing 2 and the heat exchanger 6 is maintained even due to vibrations during operation of the outdoor unit 1.

[0062] Next, the operation and effects of the outdoor unit 1 according to the first embodiment will be described.

[0063] As shown in FIG. 2 , when power is supplied to the electronic board 9c from the external AC power line 14 via the internal power line 15, the electronic board 9c enters a standby state. When the electronic board 9c receives an operation start command signal from the indoor unit via a communication signal line between the indoor unit and the outdoor unit 1 (not shown), it starts operating the outdoor unit 1. Specifically, the electronic board 9c outputs a drive signal to the fan motor 5b via the fan drive wire 12, driving the fan motor 5b. The electronic board 9c also outputs another drive signal to the compressor 8 via the compressor drive wire 13, driving the compressor 8. The drive signal output by the electronic board 9c typically uses a square-wave pulse generated by switching on a power semiconductor. Therefore, the drive signal contains high-frequency components, such as switching noise from the power semiconductor and harmonic components of the square-wave pulse, that are not actually required to drive the AC motors of the compressor 8 and the fan motor 5b. These high-frequency components are sources of electromagnetic noise and can contribute to the electromagnetic noise being emitted outside the housing 2 via a transmission path, which will be described later.

[0064] FIG. 13 is a schematic diagram showing the transmission path of electromagnetic noise as an electrical circuit in the outdoor unit 1 of the air conditioner according to the first embodiment. In FIG. 13, the heat exchanger 6 is indicated by dotted hatching for ease of understanding. For example, if a three-phase AC motor is used as the compressor 8, electromagnetic noise generated on the electronic board 9c is transmitted to the housing of the compressor 8 via the three-phase motor winding neutral point 8d and the parasitic capacitance 8b existing between the motor winding 8a and the housing of the compressor 8. A portion of the electromagnetic noise transmitted to the housing of the compressor 8 is transmitted to the housing floor panel 2a and then returned to the electronic board 9c. However, due to impedance components such as the contact resistance 8c between the housing of the compressor 8 and the housing floor panel 2a, a portion of the electromagnetic noise transmitted to the housing of the compressor 8 is transmitted to the heat exchanger 6 through the refrigerant piping 18.

[0065] The characteristics of the parasitic impedance components of the heat exchanger 6 vary depending on the structure of the heat exchanger 6. As an example, assume that the heat exchanger 6 is a parallel-flow heat exchanger equipped with fins 6f and flat refrigerant conduits 6e as shown in FIG. 8. An equivalent circuit is shown in which the parasitic inductance 23 of the heat exchanger 6 is combined as shown in FIG. 13. The parasitic impedance components, such as the parasitic inductance 23 of the heat exchanger 6, exist in a complex manner as a distributed constant circuit as shown in FIG. 13. Because the heat exchanger 6 and the housing 2 are electrically insulated by the first insulating member 7a and the second insulating member 7b, parasitic capacitances 22a and 22b are generated between the heat exchanger 6 and the housing 2. That is, a parasitic capacitance 22a is generated between the heat exchanger 6 and the housing bottom panel 2a, and a parasitic capacitance 22b is generated between the heat exchanger 6 and the housing top panel 2b. The parasitic capacitances 22a and 22b are generated on the electromagnetic noise transmission path.

[0066] 14 is an equivalent circuit diagram of a path along which a current that becomes electromagnetic noise propagates in the outdoor unit 1 of the air conditioner according to the first embodiment when the outdoor unit 1 does not include the conductive member 3. The electromagnetic noise propagates from the electronic board 9c through the compressor 8 to the heat exchanger 6 and the housing 2 shown in FIG. 13, causing resonance between the heat exchanger 6 and the parasitic inductance 23, causing resonance between the heat exchanger 6 and the parasitic capacitances 22a and 22b, and causing resonance between the heat exchanger 6 and the parasitic impedance components such as the parasitic inductance 24 of each panel of the housing 2. At this time, a change in voltage occurs in the parasitic capacitances 22a and 22b due to the resonance.

[0067] FIG. 15 is a rear view of the outdoor unit 1 of the air conditioner according to the first embodiment, illustrating locations where electromagnetic noise occurs when the outdoor unit 1 does not include the conductive member 3. In FIG. 15, the heat exchanger 6 is hatched for ease of understanding. Gaps G1, G2, G3, and G4 are formed between the heat exchanger 6 and each panel of the housing 2 to ensure electrical insulation. In FIG. 15, the locations of the gaps G1, G2, G3, and G4 are surrounded by dashed lines. Although FIG. 15 illustrates the gaps G1, G2, G3, and G4 as not being present in some areas between the heat exchanger 6 and the housing 2, in reality, the gaps G1, G2, G3, and G4 are elongated and extend around the four sides of the heat exchanger 6. The gaps G1, G2, G3, and G4 are locations where electromagnetic noise occurs when the outdoor unit 1 does not include the conductive member 3. Voltage changes occur between the heat exchanger 6 and the housing floor panel 2a and between the heat exchanger 6 and the housing top panel 2b through the parasitic capacitances 22a and 22b shown in Fig. 13. As a result, the gaps G1, G2, G3, and G4 function as slot antennas, generating additional electromagnetic noise in response to changes in voltage applied across the gaps G1, G2, G3, and G4. If the outdoor unit 1 does not include a conductive member 3, the electromagnetic noise generated in the gaps G1, G2, G3, and G4 is radiated to the outside of the housing 2 through the air intake port 2i.

[0068] FIG. 16 is an equivalent circuit diagram of a current path that causes electromagnetic noise when the heat exchanger 6 and the housing 2 are in direct contact without the insulating member 7 in the outdoor unit 1 of the air conditioner according to the first embodiment. By removing the first insulating member 7a and the second insulating member 7b shown in FIG. 15, the heat exchanger 6 and each panel of the housing 2 are electrically connected. That is, the heat exchanger 6 and each panel of the housing 2 are electrically short-circuited. Therefore, as shown in FIG. 16, the parasitic capacitances 22a and 22b generated between the heat exchanger 6 and each panel of the housing 2 are short-circuited. As a result, no voltage change occurs between the heat exchanger 6 and the housing bottom panel 2a and between the heat exchanger 6 and the housing top panel 2b shown in FIG. 15 through the parasitic capacitances 22a and 22b shown in FIG. 16, and electromagnetic noise does not occur in the gaps G1, G2, G3, and G4.

[0069] 15 is made of dissimilar metals, if no insulating member 7 is provided between the heat exchanger 6 and the housing 2, electromagnetic noise generation in the gaps G1, G2, G3, and G4 can be prevented and the radiation of electromagnetic noise outside the housing 2 can be reduced, but corrosion occurs in the heat exchanger 6, which has a low natural potential, at the contact points between the heat exchanger 6 and the housing 2. On the other hand, if an insulating member 7 is provided between the heat exchanger 6 and the housing 2, corrosion in the heat exchanger 6, which has a low natural potential, can be prevented at the contact points between the heat exchanger 6 and the housing 2, but electromagnetic noise occurs in the gaps G1, G2, G3, and G4, increasing the amount of electromagnetic noise radiation outside the housing 2.

[0070] As shown in FIG. 12 , this embodiment includes a box-shaped housing 2 made of a first metal, a heat exchanger 6 made of a second metal having a different natural potential from the first metal, disposed within the housing 2, and fixed to the housing 2 via an insulating member 7, and a conductive member 3 made of a non-metal and disposed within the housing 2. The conductive member 3 is fixed to the housing 2 and electrically connected to the housing 2, and is also electrically connected to the heat exchanger 6. This configuration electrically connects the heat exchanger 6 and the housing 2 via the conductive member 3. Therefore, parasitic capacitances 22a and 22b generated between the heat exchanger 6 and each panel of the housing 2 shown in FIG. 13 are short-circuited. This suppresses changes in voltage generated through the parasitic capacitances 22a and 22b between the heat exchanger 6 and the housing 2, thereby suppressing electromagnetic noise radiated from gaps G1, G2, G3, and G4 shown in FIG. 15 .

[0071] In this embodiment, as shown in Fig. 12, the heat exchanger 6 and the housing 2 do not come into direct contact with each other, and therefore corrosion due to contact between the heat exchanger 6 and the housing 2 can be prevented. Furthermore, in this embodiment, the conductive member 3 is made of a non-metal, and therefore corrosion due to contact between the housing 2 and the conductive member 3 and corrosion due to contact between the heat exchanger 6 and the conductive member 3 can be prevented. In other words, with a simple structure in which the outdoor unit 1 is provided with the conductive member 3, it is possible to achieve both corrosion prevention and electromagnetic noise reduction.

[0072] In this embodiment, as shown in Fig. 12, the conductive member 3 is fixed to and electrically connected to the housing side panel 2f and the partition panel 4. However, the conductive member 3 may be fixed to all of the housing floor panel 2a, the housing top panel 2b, the housing front panel 2e, the housing rear panel 2h, the housing side panels 2f and 2g, and the partition panel 4 shown in Fig. 1. This strengthens the electrical connection between the panels, thereby reducing the contact resistance and parasitic inductance 23 of the housing 2 shown in Fig. 13. This reduces the electromagnetic noise, i.e., the noise terminal voltage and interference power intensity, transmitted between the electronic board 9c, the compressor 8, and each panel of the housing 2.

[0073] In this embodiment, since the natural potential of the first metal is higher than the natural potential of the second metal, if the heat exchanger 6 is in direct contact with the housing 2, corrosion will occur in the heat exchanger 6 made of the second metal. In this regard, in this embodiment, since the heat exchanger 6 is not in direct contact with the housing 2 as described above, corrosion of the heat exchanger 6 can be prevented.

[0074] In this embodiment, the first metal is iron or an iron alloy, which increases the strength of the housing 2 made of the first metal. Also, in this embodiment, the second metal is aluminum or an aluminum alloy, which increases the thermal conductivity of the heat exchanger 6 made of the second metal.

[0075] Conventional heat exchangers include serpentine heat exchangers and aluminum parallel-flow heat exchangers. Both serpentine and parallel-flow heat exchangers have fins and refrigerant conduits. In serpentine heat exchangers, aluminum is typically used for the fins and copper for the refrigerant conduits. When iron is used for the housing 2, the magnitude relationship of the standard electrode potentials of the respective metals is aluminum < iron < copper. That is, the magnitude relationship of the standard electrode potentials of the respective metal components is fins < housing 2 < refrigerant conduits. If the fins and refrigerant conduits of a serpentine heat exchanger are in direct contact with the housing 2 and moisture adheres to the contact points, corrosion may occur in the fins, which have a lower standard electrode potential than the housing 2, but corrosion will not occur in the refrigerant conduits, which have a higher standard electrode potential than the housing 2.

[0076] On the other hand, in an aluminum parallel-flow heat exchanger, the fins and refrigerant conduits are made of aluminum. Therefore, if the housing 2 is made of iron, corrosion may occur in both the fins and the refrigerant conduits. If corrosion occurs in the refrigerant conduits and holes form, the refrigerant in the refrigerant conduits will leak into the atmosphere. This leakage of refrigerant into the atmosphere impairs the air conditioner's heating and cooling functions. Because corrosion is so detrimental to aluminum parallel-flow heat exchangers, it is important to take measures to prevent corrosion. Measures to reduce the electromagnetic noise generated by taking corrosion prevention measures must also be taken. Therefore, achieving both corrosion prevention and electromagnetic noise reduction using the nonmetallic conductive member 3 shown in FIG. 12 , as in this embodiment, is particularly useful when using a heat exchanger, such as an aluminum parallel-flow heat exchanger, where corrosion is a significant detriment. In other words, using a non-metallic conductive member 3 as in this embodiment to prevent corrosion and reduce electromagnetic noise is particularly useful when using a heat exchanger in which the natural potential of the refrigerant conduit is lower than the natural potential of surrounding members such as the housing 2.

[0077] The installation location and shape of the conductive member 3 are not limited to the example shown in the figure. For example, the conductive member 3 may be fixed to the housing floor panel 2a, the housing top panel 2b, etc., or may be electrically connected to any surface of the heat exchanger 6. The shape of the conductive member 3 may be changed as appropriate so that the conductive member 3 can be electrically connected to the housing 2 and the heat exchanger 6.

[0078] The entire heat exchanger 6 does not need to be made of the second metal, but at least a part of the heat exchanger 6 may be made of the second metal. For example, at least one of the fins and the refrigerant conduit of the heat exchanger 6 may be made of the second metal.

[0079] The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, and parts of the configurations may be omitted or modified without departing from the spirit of the invention. [Explanation of symbols]

[0080] 1 outdoor unit of air conditioner, 2 housing, 2a housing floor panel, 2b housing top panel, 2c first connecting panel, 2d second connecting panel, 2e housing front panel, 2f, 2g housing side panel, 2h housing rear panel, 2i air intake port, 2j exhaust port, 2k opening, 2m inner surface, 3 conductive member, 3a first conductive member, 3b second conductive member, 3c first plate portion, 3d second plate portion, 3e fixing portion, 3f plate portion, 3g connecting portion, 4 partition panel, 4a first partition portion, 4b second partition portion, 4c introduction hole, 4d, 6i side surface, 5 blower, 5a support, 5b fan motor, 5c propeller fan, 6 heat exchanger, 6a first heat exchange portion, 6b second heat exchange portion, 6c, 6d header, 6e Refrigerant conduit, 6f fin, 6g, 6h front surface, 7 insulating member, 7a first insulating member, 7b second insulating member, 8 compressor, 8a motor winding, 8b, 22a, 22b parasitic capacitance, 8c contact resistance, 8d three-phase motor winding neutral point, 9 electronic board box, 9a lower box, 9b upper cover, 9c electronic board, 9d heat sink, 9e hole, 10 fan chamber, 11 electrical chamber, 12 fan drive wire, 13 compressor drive wire, 14 external AC power line, 15 internal power line, 16 earth wire, 17 stop valve, 18 refrigerant piping, 19 connection portion, 20 interface panel, 20a interface vertical wall, 20b upper connecting flange portion, 20c interface horizontal wall, 20d lower connecting flange portion, 20e earth connection point, 21 terminal block, 22 Interface cover, 23, 24 Parasitic inductance.

Claims

1. a box-shaped housing formed from a first metal and constituting an outer shell of an outdoor unit of an air conditioner; a heat exchanger at least a portion of which is formed from a second metal having a natural potential different from that of the first metal, the heat exchanger being disposed within the housing and fixed to the housing via a non-conductive member; a conductive member formed of a nonmetal and disposed within the housing; The conductive member is fixed to the housing and electrically connected to the housing, and is also electrically connected to the heat exchanger in the outdoor unit of an air conditioner.

2. the housing has a housing bottom panel, a housing top panel disposed above the housing bottom panel, and a housing front panel, a housing rear panel, and housing side panels connecting the housing bottom panel and the housing top panel; 2. The outdoor unit of an air conditioner according to claim 1, wherein the conductive member is fixed to at least one of the housing floor panel, the housing top panel, the housing front panel, the housing rear panel, and the housing side panel.

3. The outdoor unit of an air conditioner according to claim 1 , wherein the natural potential of the first metal is higher than the natural potential of the second metal.

4. the first metal is iron or an iron alloy; 2. The outdoor unit of an air conditioner according to claim 1, wherein the second metal is aluminum or an aluminum alloy.

5. 5. The outdoor unit of an air conditioner according to claim 1, wherein the heat exchanger is a parallel flow type heat exchanger.

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