DESCRIPTION
Title of Invention
OUTDOOR UNIT FOR AIR-CONDITIONING APPARATUS
Technical Field
[0001]
The present invention relates to an outdoor unit for an air-conditioning apparatus, and particularly relates to a bottom plate of a casing of the outdoor unit. Background Art [0002]
Some heat exchangers mounted on conventional air-conditioning apparatuses include fins and pipes made of aluminum. In an outdoor unit of an air-conditioning apparatus on which such a heat exchanger is mounted, pitting corrosion occurs to any aluminum pipe when a bottom plate of the outdoor unit is made of metal more electrically noble than aluminum, in other words, having ionization tendency lower than that of aluminum in a structure in which the bottom plate of the outdoor unit is in contact with a lower end part of the heat exchanger. [0003]
To prevent this electrolytic corrosion, a support component made of metal or resin less electrically noble than aluminum has been conventionally interposed between the heat exchanger and the bottom plate. However, water such as rainwater and drain water potentially accumulates in the support component, and metal and acid elements included in the accumulating water cause electrolytic corrosion to the lower end part of the heat exchanger in some cases. [0004]
Patent Literature 1 discloses a structure in which the support component is provided with a water discharge hole through which water inside the support component is discharged to prevent water accumulation in the support component. Citation List Patent Literature [0005]
1

Patent Literature 1: Japanese Unexamined Patent Application Publication No. 2013-160444 Summary of Invention Technical Problem [0006]
However, any substance having discharged through the water discharge hole of the support component potentially stays and accumulates on the bottom plate nearby, and any accumulating solid matter potentially comes in contact with the bottom plate and the lower end part of the heat exchanger through the water discharge hole provided to the support component. When the solid matter in this state contains water, the bottom plate and the lower end part of the heat exchanger are electrically communicated with each other, causing electrolytic corrosion. Solid matter such as dust and corroded metal components nearby accumulates around the support component on the bottom plate in some cases. In such a case, too, any accumulating solid matter provides electrical communication between the bottom plate and the lower end part of the heat exchanger through the water discharge hole, causing electrolytic corrosion. [0007]
The present invention is intended to solve the above-described problems and provide a highly reliable outdoor unit for an air-conditioning apparatus in which a support component is provided with a water discharge hole but electrolytic corrosion of a lower end part of a heat exchanger can be reduced. Solution to Problem [0008]
An outdoor unit for an air-conditioning apparatus according to an embodiment of the present invention includes a casing, a heat exchanger disposed in the casing, a support component covering and supporting a lower end part of the heat exchanger from below and having a water discharge hole for discharging water in the support component to an outside, and an insulation sheet interposed between the support

component and a bottom plate of the casing. The insulation sheet covers a bottom surface of the support component. Advantageous Effects of Invention [0009]
An embodiment of the present invention can provide a highly reliable outdoor unit for an air-conditioning apparatus in which the support component is provided with the water discharge hole but electrolytic corrosion of the lower end part of the heat exchanger can be reduced by the insulation sheet. Brief Description of Drawings [0010]
[Fig. 1] Fig. 1 is a perspective view of an outdoor unit 100 for an air-conditioning apparatus according to Embodiment 1 of the present invention.
[Fig. 2] Fig. 2 is an exploded perspective view of the outdoor unit 100 for an air-conditioning apparatus according to Embodiment 1 of the present invention.
[Fig. 3] Fig. 3 is a schematic diagram of a heat exchanger 200 provided in the outdoor unit 100 for an air-conditioning apparatus according to Embodiment 1 of the present invention.
[Fig. 4] Fig. 4 is a schematic perspective view of a support component 201 of the outdoor unit 100 for an air-conditioning apparatus according to Embodiment 1 of the present invention.
[Fig. 5] Fig. 5 is a plan view of the support component 201 of the outdoor unit 100 for an air-conditioning apparatus according to Embodiment 1 of the present invention.
[Fig. 6] Fig. 6 is a schematic plan view selectively illustrating a bottom plate 300, the support component 201, and their related members of the outdoor unit 100 for an air-conditioning apparatus according to Embodiment 1 of the present invention.
[Fig. 7] Fig. 7 is a main-part schematically enlarged view of a section taken along line A-A in Fig. 6.

[Fig. 8] Fig. 8 is a main-part schematically enlarged view of the section taken along line A-A in Fig. 6 similarly to Fig. 7, illustrating a state in which deposit 500 accumulates around the support component 201.
[Fig. 9] Fig. 9 is a schematic plan view of the bottom plate 300 of the outdoor unit 100 for an air-conditioning apparatus according to Embodiment 2 of the present invention.
[Fig. 10] Fig. 10 is a main-part schematically enlarged view of a section taken along line B-B in Fig. 9. Description of Embodiments [0011]
Embodiments of the present invention will be described below with reference to the accompanying drawings. In the drawings, the same or equivalent parts are denoted by the same reference sign, and description of the parts will be omitted or simplified as appropriate. The shape, size, arrangement, and other physical features of any component illustrated in the drawings may be changed within the scope of the present invention as appropriate. [0012] Embodiment 1
Fig. 1 is a perspective view of an outdoor unit 100 for an air-conditioning apparatus according to Embodiment 1 of the present invention. Fig. 2 is an exploded perspective view of the outdoor unit 100 for an air-conditioning apparatus according to Embodiment 1 of the present invention. [0013]
As illustrated in Fig. 1, a casing 100a of the outdoor unit 100 includes a top plate 101, a front plate 102, a side plate 103, and a bottom plate 300. The casing 100a further includes a fan grille 104, a connection-terminal protecting cover 105, and a refrigerant-pipe protecting cover 106. As illustrated in Fig. 2, mainly, a heat exchanger 200, a compressor 110, a partition plate 111, a fan motor 112, a fan-motor supporting member 113, and a propeller fan 114 are disposed inside the casing 100a of the outdoor unit 100.

[0014]
The casing 100a is partitioned into a machine room 150a and an air-sending device room 150b by the partition plate 111. For example, the compressor 110 is disposed in the machine room 150a. For example, the heat exchanger 200, the fan motor 112, the fan-motor supporting member 113, and the propeller fan 114 are disposed in the air-sending device room 150b. [0015]
The bottom plate 300 is shaped in a box having an opened upper surface, and serves as a bottom part of the outdoor unit 100. A component such as the heat exchanger 200 housed in the outdoor unit 100 is disposed on the bottom plate 300. [0016]
The heat exchanger 200 has a substantially L shape in plan view, extending across a left side surface and a back surface of the air-sending device room 150b. The heat exchanger 200 is provided with heat-exchanger support components 201 (201a and 201b) to be described later at two parts that are upper and lower end parts on a front left side. The following describes the configuration of the heat exchanger 200 in detail with reference to Fig. 3. [0017]
Fig. 3 is a schematic diagram of the heat exchanger 200 provided in the outdoor unit 100 for an air-conditioning apparatus according to Embodiment 1 of the present invention. Fig. 3 illustrates a state before the heat exchanger 200 is bent in the L shape.
As illustrated in Fig. 3, the heat exchanger 200 includes header pipes 250 and 251 each extending in a vertical direction and spaced from each other, a plurality of flat pipes 252 extending in parallel between the header pipes 250 and 251 and spaced in the vertical direction from each other, and a plurality of corrugated heat transferring fins 253 each disposed between adjacent ones of the plurality of flat pipes 252. The flat pipes 252 are each a heat transfer pipe in which a passage for circulating refrigerant is provided and that extend in a horizontal direction. Each flat pipe 252 has both end parts joined with the header pipes 250 and 251 through, for

example, brazing filler metal, which allows communication between the inside of each
header pipe and the passage of the flat pipe 252.
[0018]
Side plates 256 for preventing deformation of the heat transferring fins 253 are provided on outer surface sides of an uppermost one and a lowermost one of the heat transferring fins 253 in Fig. 3, which correspond to the outermost of a part in which the flat pipes 252 and the heat transferring fins 253 are alternately stacked. [0019]
A header-pipe partition plate 257 is provided in the header pipe 250 to achieve efficient heat exchange inside the heat exchanger 200, dividing the inside of the header pipe 250 in the vertical direction. Among upper and lower rooms of the header pipe 250 provided through the division by the header-pipe partition plate 257, the upper room is connected with a connection pipe 254, and the lower room is connected with a connection pipe 255. The connection pipes 254 and 255 are connected with pipes of a refrigerant passage (not illustrated). [0020]
The heat exchanger 200 is not limited to the above-described structure. For example, flat plate fins may be provided in place of the corrugated fins. In the above-described configuration, the header-pipe partition plate 257 is provided in the header pipe 250, but no header-pipe partition plate 257 or a plurality of header-pipe partition plates 257 may be provided. [0021]
The header pipes 250 and 251, the flat pipes 252, the heat transferring fins 253, the connection pipes 254 and 255, the side plates 256, and the header-pipe partition plate 257 are all made of aluminum. In this case, aluminum includes aluminum alloy. [0022]
As illustrated in Fig. 2, the header pipe 251 has a lower end part 251a and an upper end part 251b covered by heat-exchanger support components 201a and 201b. Hereinafter, these heat-exchanger support components 201a and 201b are

collectively referred to as support components 201 in some cases. The support components 201 are made of metal or resin less noble than aluminum and act to avoid contact between the header pipe 250 and the bottom plate 300, in other words, contact between the lower end part of the heat exchanger and the bottom plate 300. In the example illustrated in Fig. 2, the two support components 201 are provided at upper and lower parts on one end side (left end side) of the heat exchanger 200 in the left-right direction, but may be also provided on the other end side (right end side). The support components 201 are provided to support the heat exchanger 200 and avoid contact between the heat exchanger 200 and the bottom plate 300. The number of the support components 201 and the positions of the support components 201 are not particularly limited. [0023]
Fig. 4 is a schematic perspective view of the support component 201 of the outdoor unit 100 for an air-conditioning apparatus according to Embodiment 1 of the present invention. Fig. 5 is a plan view of the support component 201 of the outdoor unit 100 for an air-conditioning apparatus according to Embodiment 1 of the present invention.
Each support component 201 includes a bottom surface part 202a and a side surface part 202b provided to an outer periphery of the bottom surface part 202a, and is shaped in a bottomed cylinder having one end part blocked. A water discharge hole 210 for discharging any unwanted substance such as water having flowed into the support component 201 to an outside is formed in the side surface part 202b of the support component 201. The configuration with the water discharge hole 210 can prevent corrosion of the header pipe 250 due to, for example, water having flowed in through a gap of the support component 201 and hence prevent refrigerant leakage. [0024]
Fig. 6 is a schematic plan view selectively illustrating the bottom plate 300, the support component 201, and their related members of the outdoor unit 100 for an air-conditioning apparatus according to Embodiment 1 of the present invention. In Fig.

6, the support component 201 and the heat exchanger 200 are illustrated with dashed lines.
The bottom plate 300 is provided with a main discharge hole 301 formed as a first discharge hole for discharging any unwanted substance such as rainwater having flowed onto the bottom plate 300. The main discharge hole 301 is positioned below the heat exchanger 200. An insulation sheet 310 is disposed on the bottom plate 300. The following describes the insulation sheet 310 with reference to Figs. 7 and 8. [0025]
Fig. 7 is a main-part schematically enlarged view of a section taken along line A-A in Fig. 6.
As illustrated in Figs. 6 and 7, the insulation sheet 310 is interposed between the support component 201 and the bottom plate 300 and covers a bottom surface of the support component 201. Specifically, the insulation sheet 310 is shaped in a plate larger than the bottom surface of the support component 201 and provided in contact with the entire bottom surface of the support component 201. The insulation sheet 310 is provided to prevent conduction between the lower end part 251a of the header pipe 250 and the bottom plate 300 of the casing 100a through the water discharge hole 210. The insulation sheet 310 is made of an electric insulator such as butyl rubber or polyester. The insulation sheet 310 preferably has a contact surface made of a sticky material to fix the position of the insulation sheet 310 to the bottom plate 300. [0026]
Fig. 8 is a main-part schematically enlarged view of the section taken along line A-A in Fig. 6 similarly to Fig. 7, illustrating a state in which deposit 500 accumulates around the support component 201.
The deposit 500 is solid matter as accumulation of dust or sand containing water from air, or accumulation of fluid such as rainwater. The deposit 500 accumulates inside and outside of the side surface part 202b of the support component 201 and is integrated through the water discharge hole 210. The deposit

500 does not exist at an initial stage of usage, but is formed by accumulation and
inflow through use of an air-conditioning apparatus and elapse of time.
[0027]
When the insulation sheet 310 is not provided, the deposit 500 serves as a conduction path, so that the bottom plate 300 and the header pipe 251 made of dissimilar metals cause conduction through the water discharge hole 210, and as a result, electrolytic corrosion occurs. However, the provision of the insulation sheet 310 prevents the conduction between the bottom plate 300 and the header pipe 251 when the deposit 500 smaller than the insulation sheet 310 is generated, thereby reducing corrosion due to electrolytic corrosion. In addition, the provision of the insulation sheet 310 increases a spatial distance between the bottom plate 300 and the lower end part 251a of the header pipe 251, thereby increasing an insulation distance between the bottom plate 300 and the lower end part 251a of the header pipe 251. [0028]
As described above, according to Embodiment 1, the insulation sheet 310 is interposed between the bottom plate 300 of the casing 100a and the support component 201 to reduce corrosion and refrigerant leakage due to electrolytic corrosion of the lower end part of the heat exchanger. Consequently, the outdoor unit 100 for an air-conditioning apparatus is highly reliable for long-term use. [0029] Embodiment 2
Fig. 9 is a schematic plan view of the bottom plate 300 of the outdoor unit 100 for an air-conditioning apparatus according to Embodiment 2 of the present invention. Fig. 10 is a main-part schematically enlarged view of a section taken along line B-B in Fig. 9. The following mainly describes any feature of Embodiment 2 that is different from that of Embodiment 1.
Embodiment 2 is characterized in that the bottom plate 300 of Embodiment 1 illustrated in Fig. 6 further has a sub discharge hole 350, which is a through hole, as a second discharge hole. Consequently, the bottom plate 300 is provided with the

main discharge hole 301 and the sub discharge hole 350, which is provided in the vicinity of the insulation sheet 310, in other words, below the circumference of the insulation sheet 310. The configuration according to Embodiment 2 provided with the sub discharge hole 350 provides an enhanced reduction effect on generation of the deposit 500. [0030]
The reduction effect on generation of the deposit 500 is affected by the position of the sub discharge hole 350. Specifically, the reduction effect on generation of the deposit 500 is largest when a distance a between an edge of the insulation sheet 310 closer to the sub discharge hole 350 and an edge of the sub discharge hole 350 closer to the insulation sheet 310 in the horizontal direction is zero, in other words, when the edge of the insulation sheet 310 is in contact with the edge of the sub discharge hole 350. [0031]
When the distance a is negative, in other words, when the insulation sheet 310 covers the sub discharge hole 350, the sub discharge hole 350 has a reduced water discharge capacity, and the reduction effect on generation of the deposit 500 degrades. Thus, any arrangement for which the distance a is negative is inappropriate. The insulation sheet 310 is often joined with the bottom plate 300 by an adhesive material to fix the position of the insulation sheet 310. However, such adhesive joint potentially flakes off when the distance a is negative. [0032]
For the above-described reasons, it is most preferable that the distance a is zero at the time of the provision of the insulation sheet 310. However, it is difficult to maintain the distance a to be zero in every outdoor unit because of manufacturing variance, although any negative distance a degrades the effect otherwise. Thus, the distance a is preferably 0 mm to 3 mm approximately. [0033]
As described above, according to Embodiment 2, the effect same as that of Embodiment 1 can be achieved, and additionally, an effect described below is

achieved by the sub discharge hole 350 provided to the bottom plate 300.
Specifically, discharge of any unwanted substance (rainwater or foreign object) in the
vicinity of the support component 201 can be facilitated to further reduce generation
of the deposit 500.
[0034]
As the distance a between the sub discharge hole 350 and the insulation sheet
310 in the horizontal direction is 0 mm to 3 mm, the water discharge capacity of the
sub discharge hole 350 and the reduction effect on generation of the deposit 500 can
be both achieved.
Reference Signs List
[0035]
100 outdoor unit 100a casing 101 top plate 102 front plate 103 side plate 104 fan grille 105 connection-terminal protecting
cover 106 refrigerant-pipe protecting cover 110 compressor 111 partition plate 112 fan motor 113 fan-motor supporting member 114 propeller fan 150a machine room 150b air-sending device room 200 heat exchanger 201 heat-exchanger support component 201a heat-exchanger support
component 201b heat-exchanger support component 202a bottom surface part 202b side surface part 210 water discharge hole 250 header pipe 251 header pipe 251a lower end part 251b upper end part 252 flat
pipe 253 heat transferring fin 254 connection pipe 255 connection pipe
256 side plate 257 header-pipe partition plate 300 bottom plate
301 main discharge hole 310 insulation sheet 350 sub discharge
hole 500 deposit

CLAIMS [Claim 1]
An outdoor unit for an air-conditioning apparatus, the outdoor unit comprising:
a casing;
a heat exchanger disposed in the casing;
a support component covering and supporting a lower end part of the heat exchanger from below and having a water discharge hole for discharging water in the support component to an outside; and
an insulation sheet interposed between the support component and a bottom plate of the casing, the insulation sheet covering a bottom surface of the support component. [Claim 2]
The outdoor unit for an air-conditioning apparatus of claim 1, wherein the bottom plate has a first discharge hole and a second discharge hole each for discharging unwanted substance having flowed onto the bottom plate. [Claim 3]
The outdoor unit for an air-conditioning apparatus of claim 2, wherein the first discharge hole is positioned below the heat exchanger, and the second discharge hole is positioned below a circumference of the insulation sheet. [Claim 4]
The outdoor unit for an air-conditioning apparatus of claim 2 or 3, wherein a distance between the second discharge hole and the insulation sheet in a horizontal direction is 0 mm to 3 mm. [Claim 5]
The outdoor unit for an air-conditioning apparatus of any one of claims 1 to 4, wherein
the heat exchanger includes header pipes each extending in a vertical direction and spaced from each other and a plurality of fins and a plurality of heat transfer pipes provided between the header pipes, and

a lower end part of one of the header pipes is the lower end part of the heat exchanger.