outdoor unit

The outdoor unit design with an isolation member and vents addresses access and temperature issues, enabling easy control board replacement and maintaining cooling efficiency.

JP7797119B2Active Publication Date: 2026-01-13MITSUBISHI HEAVY IND THERMAL SYST
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Patent Information

Application Number
JP2021081630
Authority / Receiving Office
JP · JP
Patent Type
Patents
Current Assignee / Owner
Filing Date
2021-05-13
Publication Date
2026-01-13
Estimated Expiration
2041-05-13

AI Technical Summary

Technical Problem

The control box in outdoor units of air conditioners is difficult to access when obstacles are present above, and high temperatures due to warm air accumulation reduce cooling capacity.

Method used

An outdoor unit design with an isolation member between the control box and the top plate, allowing easy replacement of the control board and incorporating a water impermeable wall to form a space above the control box, with vents to dissipate heat and prevent temperature rise.

Benefits of technology

Facilitates easy replacement of the control board and suppresses temperature increases, maintaining cooling efficiency and preventing damage from high temperatures.

✦ Generated by Eureka AI based on patent content.

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Patent Text Reader

Abstract

To provide an outdoor unit in which a control board in a control box can be easily replaced.SOLUTION: An outdoor unit comprises: an outdoor fan 5 for introducing outside air; a compressor 13 for compressing a refrigerant; a control board provided with electrical components for controlling the outdoor fan 5 and / or the compressor 13; a control box 20 housing the control board; a housing 3 housing the outdoor fan 5, the compressor 13, the control board, and the control box 20; and a water shielding wall 30 that separates the control box 20 from a top plate of the housing so as to form an upper space R3 between the water shielding wall and the top plate. The control board is removable in a state in which the water shielding wall 30 is fixed to the housing 3 side.SELECTED DRAWING: Figure 2
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Description

[Technical Field]

[0001] The present disclosure relates to an outdoor unit used in an air conditioner. [Background technology]

[0002] BACKGROUND ART An outdoor unit used in an air conditioner is provided with a control box that houses a control board equipped with electrical components that control the compressor and the like (Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-281286 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-094926 Summary of the Invention [Problem to be solved by the invention]

[0004] However, as disclosed in each of the above patent documents, the control box is located near the top plate of the outdoor unit housing, so if there is an obstacle above the outdoor unit that makes it difficult to access the control box from above, it becomes difficult to replace the control board inside the control box.

[0005] Furthermore, when an air conditioner is operated in cooling mode in conditions where the outside temperature is high, such as in the summer, warm air (hot air) accumulates in the space above the outdoor unit, causing it to become very hot. When the temperature inside the outdoor unit rises too high, it becomes necessary to limit the current flowing through the electrical components on the control board to prevent an abnormal rise in temperature, which results in a problem of reduced cooling capacity.

[0006] The present disclosure has been made in consideration of the above circumstances, and aims to provide an outdoor unit in which the control board inside the control box can be easily replaced. Another object of the present disclosure is to provide an outdoor unit that can suppress temperature increases in electrical components mounted on a control board. [Means for solving the problem]

[0007] In order to solve the above problems, the outdoor unit of the present disclosure includes an outdoor fan that introduces outside air, a compressor that compresses a refrigerant, a control board on which electrical components that control the outdoor fan and / or the compressor are mounted, a control box that houses the control board, a housing that houses the outdoor fan, the compressor, the control board, and the control box, and an isolation member that isolates the control box from the top plate of the housing so as to form a space between the control board and the top plate, and the control board is removable with the isolation member fixed to the housing side. The isolation member is provided between the top plate and the control box. are. [Effects of the Invention]

[0008] The control board inside the control box can be easily replaced. The temperature rise of the electrical components mounted on the control board can be suppressed. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view showing the appearance of an outdoor unit according to an embodiment of the present disclosure. [Figure 2] 2 is a perspective view showing the outdoor unit of FIG. 1 with the service panel and top plate removed. FIG. [Figure 3] FIG. 3 is a perspective view showing a state in which the compressor and the control box shown in FIG. 2 are removed. [Figure 4] FIG. 3 is a perspective view showing a state in which the impermeable wall shown in FIG. 2 has been removed. [Figure 5] FIG. 2 is a perspective view showing a control box. [Figure 6] FIG. 6 is an exploded perspective view of the control box of FIG. 5. [Figure 7] FIG. [Figure 8]FIG. 4 is a perspective view showing a part of the outdoor unit shown in FIG. 3 in section. [Figure 9] FIG. 10 is a perspective view showing a state in which a cover member is removed during the replacement work of the control board. [Figure 10] FIG. 10 is a perspective view showing a state in which the control board is removed during the control board replacement work. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment according to the present disclosure will be described with reference to the drawings. An outdoor unit 1 according to this embodiment is shown in Figure 1. The outdoor unit 1 is installed outdoors and is connected to an indoor unit (not shown) via refrigerant piping (not shown). The indoor unit provides air conditioning for the room.

[0011] The outdoor unit 1 includes a rectangular parallelepiped housing 3 made of sheet metal. An outdoor fan 5 and the like are provided inside the housing 3. The outdoor fan 5 is driven by an electric motor (not shown).

[0012] The housing 3 comprises a mesh-like fan guard 7 provided in front of the outdoor fan 5, and a service panel 9 provided to the side of the fan guard 7 (to the right in FIG. 1). The housing 3 comprises a rear panel 10 that forms the back surface, side panels 12 that connect the rear panel 10 and front panel 9 at the sides, and a top panel 11 that forms the top surface. The service panel 9 and top panel 11 are detachable from the main body of the outdoor unit 1.

[0013] 2 shows the outdoor unit 1 with the service panel 9 and top panel 11 removed. Removing the service panel 9 exposes the compressor 13. The compressor 13 is cylindrical and stands upright, and includes a compression mechanism including a scroll member and a rotary member that is driven by an inverter-driven electric motor (not shown) housed inside. The refrigerant compressed by the compression mechanism is guided to the outdoor heat exchanger 17 or the indoor heat exchanger via a four-way valve (not shown).

[0014] A partition plate 15 is provided between the compressor 13 and the outdoor fan 5. The partition plate 15 is made of sheet metal and is a wall that stands upright from the bottom plate 16 of the housing 3. As shown in FIG. 3, which shows the compressor 13 removed, the partition plate 15 has an L-shaped cross section that covers the sides and back of the compressor 13. The space on the compressor 13 side (right side in FIG. 3) separated by the partition plate 15 is a machine chamber R1, and the space on the outdoor fan 5 side (left side in FIG. 3) is a fan chamber R2. As shown in FIG. 2, an outdoor heat exchanger 17 is provided in the fan chamber R2. The outdoor heat exchanger 17 exchanges heat between outside air taken into the housing 3 by the outdoor fan 5 and a refrigerant flowing in a heat transfer tube (not shown), and functions as a condenser during cooling operation and as an evaporator during heating operation.

[0015] As shown in FIG. 2, above the compressor 13 and above the partition plate 15, a control box 20 and a water impermeable wall (isolation member) 30 are provided. The control box 20 is provided above the partition plate 15 and below the water shielding wall 30. Figure 3 shows a state in which the control box 20 has been removed, leaving the partition plate 15 and the water shielding wall 30 in place. As can be seen from the figure, the control box 20 is installed in the space between the upper end 15a of the partition plate 15 and the lower end 30f of the water shielding wall 30. As shown in Figure 4, which shows a state in which the water shielding wall 30 has been removed, the control box 20 is provided above the partition plate 15, extending horizontally.

[0016] As shown in Figures 5 and 6, the control box 20 comprises a frame body 22 that forms the outer shape, a control board 24 that is detachably fixed to the frame body 22, and a cover member 26 that covers the top of the control board 24.

[0017] The frame body 22 has a rectangular shape in a plan view and is made of sheet metal. The frame body 22 includes an upper frame 22a and a lower frame 22b connected to the upper frame 22a.

[0018] The upper frame 22a is provided with a seat 22a1 that abuts against the outer periphery of the control board 24 to support it. Screws 23 that secure the control board 24 can be attached and detached to the seat 22a1. The upper frame 22a is formed with heat dissipation fin openings 22c into which the heat dissipation fins 24a of the control board 24 are inserted. The shape of the heat dissipation fin openings 22c corresponds to the outer shape of the heat dissipation fins 24a. As shown in FIG. 5, the heat dissipation fins 24a are exposed below the upper frame 22a after passing through the heat dissipation fin openings 22c. As can be seen from FIG. 5, the lower frame 22b is not provided in the area where the heat dissipation fins 24a are exposed. The lower frame 22b is provided across a lateral area (to the right in FIGS. 5 and 6) that avoids the area where the heat dissipation fin openings 22c are provided.

[0019] The lower frame 22b protects the electrical components and wiring provided on the control board 24. For example, as can be seen with reference to Figure 4, the lower frame 22b is provided on the machine chamber R1 side with the partition plate 15 in between, and the heat dissipation fins 24a side where the lower frame 22b is not provided is provided on the fan chamber R2 side with the partition plate 15 in between. A terminal block 22d is provided on the side of the frame body 22. The terminal block 22d connects electrical wiring between the electrical components of the control board 24 and the compressor 13 and the outdoor fan 5.

[0020] The control board 24 controls the operation of the outdoor fan 5, the compressor 13, a four-way valve (not shown), etc. The control board 24 includes heat dissipation fins 24a, a plate-shaped board body 24b, and electrical components 24c mounted on the board body 24b. The board body 24b is a printed circuit board that is rectangular in plan view. Screw holes (six in FIG. 6 ) through which fixing screws 23 pass are formed around the periphery of the board body 24b. The control board 24 can be separated from the frame 22 by removing the screws 23. The electrical component 24c is an electronic component such as a capacitor, a CPU, etc. The electrical component 24c is provided on the lower surface of the board main body 24b. The heat dissipation fins 24a are used to remove heat generated by the CPU, etc., and are made of a metal material with relatively high thermal conductivity, such as an aluminum alloy, etc. The heat dissipation fins 24a are provided so as to protrude downward from the lower surface of the board main body 24b.

[0021] The cover member 26 is made of sheet metal and is shaped to cover the control board 24 from above. The cover member 26 protects the control board 24 and also protects surrounding components from sparks generated by the control board 24. The cover member 26 is shaped like a lid, with a rectangular main surface 26a and side portions 26b bent downward from each of the four sides of the main surface 26a. A plurality of protrusions 26b1 are provided on the side portions 26b. Each protrusion 26b1 is adapted to fit into a corresponding claw portion 22e provided on the upper frame 22a of the frame body 22. This allows the cover member 26 to be easily attached to and detached from the frame body 22.

[0022] As shown in FIG. 7 , the water shielding wall 30 is made of sheet metal and includes a first side wall portion 30a, a second side wall portion 30b, and a third side wall portion 30c connected in a U-shape. The height of the water shielding wall 30 is dimensioned to ensure a predetermined space above the control box 20. Specifically, the height is set to a level that allows for easy access when replacing the control board 24 installed in the control box 20, e.g., 100 mm to 150 mm. The water shielding wall 30 is provided to surround the periphery of the control box 20, more specifically, the outer periphery of the control board 24. The upper end of the water shielding wall 30 abuts against the underside of the top plate 11 (see FIG. 1 ) of the housing 3, for example, via a heat insulating material. In this case, the heat insulating material may be omitted. In this manner, the top plate 11 and the control box 20 are isolated by the water shielding wall 30, and an upper space R3 (see FIG. 2 ) is formed above the control box 20. The upper space R3 surrounded by the water impermeable wall 30 is hollow and has no devices installed therein.

[0023] As shown in Fig. 7, the first side wall 30a is a plate-like body located on the front side of the outdoor unit 1. The horizontal dimension of the first side wall 30a is smaller than the horizontal dimension of the control box 20. As a result, as shown in Fig. 2, for example, when the service panel 9 (see Fig. 1) is removed, an access opening 30d is formed on the right side of the first side wall 30a, through which the control box 20 can be accessed.

[0024] A connecting piece 30a1 protruding downward is provided at the other end (the open end on the right side) of the first side wall portion 30a. As shown in Fig. 8, the connecting piece 30a1 is used to connect to the partition plate 15. The connecting piece 30a1 and the partition plate 15 are fixed together with screws (not shown).

[0025] As shown in FIG. 7, the second side wall 30b is a plate-like member connected perpendicularly to one end (left end) of the first side wall 30a. The second side wall 30b extends in the depth direction of the outdoor unit 1. The upper end of the second side wall 30b is flush with the upper end of the first side wall 30a. The second side wall 30b is provided with vents 30b1 as through-holes. Two vents 30b1 are provided as circular holes, and are located at the center and lower end of the second side wall 30b in the width direction. However, the shape, position, and number of the vents 30b1 are not limited to those shown in FIG. 7. The vents 30b1 create a fluid flow from the upper space R3 (see FIG. 2) surrounded by the water-shielding wall 30 to the fan chamber R2. This allows the outdoor fan 5 to suck in hot air stagnating in the upper space R3.

[0026] The third side wall portion 30c is a plate-like body connected perpendicularly to one end of the second side wall portion 30b, and is located along the rear side of the outdoor unit 1. The upper end of the third side wall portion 30c is flush with the upper end of the second side wall portion 30b. The horizontal dimension of the third side wall portion 30c is larger than the horizontal dimension of the first side wall portion 30a and is also larger than the horizontal dimension of the control box 20.

[0027] A connecting piece 30c1 that protrudes downward is provided at the other end (the open end on the right side) of the third side wall portion 30c. As shown in FIG. 8, the connecting piece 30c1 is used when connecting to the partition plate 15. The connecting piece 30c1 and the partition plate 15 are fixed with screws (not shown). In this way, the water shielding wall 30 is fixed to the upper part of the partition plate 15 by the two connecting pieces 30a1, 30c1. As a result, a load applied downward from the top plate 11 is transmitted to the partition plate 15 via the water shielding wall 30. In other words, the load applied downward from the top plate 11 is not transmitted to the control box 20.

[0028] As shown in FIG. 8, a connecting member 32 is provided at the other end (open end) of the third side wall portion 30c. The connecting member 32 connects the water shielding wall 30 to the rear panel 10 of the housing 3. The connecting member 32 is used as a member for fixing the outdoor heat exchanger 17 (see FIG. 2) and also functions as an isolating member for isolating the control box 20 from the top plate 11. A notch is provided at the upper end of the connecting member 32 on the rear panel 10 side, and this notch forms an air vent 33. The air vent 33 allows a fluid flow from the upper space R3 (see FIG. 2) surrounded by the water shielding wall 30 to the fan chamber R2. This allows the outdoor fan 5 to suck in hot air stagnating in the upper space R3.

[0029] Next, a process for replacing the control board 24 of the control box 20 during maintenance of the outdoor unit 1 configured as described above will be described. First, remove the service panel 9 (see FIG. 1) as shown in Figure 2. The top panel 11 (see FIG. 1) may be removed as shown in Figure 2, or may remain in place depending on the work environment.

[0030] Next, as shown in Figure 9, the upper space R3 is accessed through the access opening 30d formed by the water shielding wall 30, and the cover member 26 is removed from the control box 20. The removal is performed by disengaging the protrusions 26b1 (see Figure 6) of the cover member 26 from the claws 22e (see Figure 6) of the frame body 22. In this process, the water shielding wall 30 and the connecting member 32 remain fixed to the partition plate 15 and are not removed.

[0031] Next, as shown in Figure 10, the control board 24 is removed from the control box 20. The removal is performed by removing the screws 23 (see Figure 6) that are fixed through screw holes 24d (see Figure 6) formed in the control board 24. Even in this process, the water impermeable wall 30 and the connecting member 32 remain fixed to the partition plate 15 and are not removed.

[0032] When installing a new control board 24, the above removal steps are performed in reverse order. That is, after the control board 24 is fixed to the control box 20 with the screws 23, the cover member 26 is placed over the control board 24 and fixed in place. Then, the service panel 9 (see FIG. 1) is attached, completing the replacement work.

[0033] The above-described embodiment has the following advantages. A water shielding wall 30 is provided above the control box 20 as an isolating member to form an upper space R3 between the control box 20 and the top plate 11. This ensures a working space above the control box 20, facilitating work such as replacing the control board 24. Furthermore, heat generated from the electrical components 24c of the control board 24 dissipates into the upper space R3, suppressing a temperature rise in the electrical components 24c.

[0034] The control board 24 can be made removable with the water shielding wall 30 fixed to the housing 3 side (specifically, the partition plate 15). This allows the control board 24 to be removed without removing the water shielding wall 30 from the housing 3 side when replacing the control board 24.

[0035] The water shielding wall 30 forms an upper space R3 above the control box 20, i.e., above the control board 24, ensuring a working space when replacing the control board 24. In particular, it is possible to access the control board 24 from the front side of the housing 3 without removing the top panel 11, which is advantageous when there is an obstacle above the top panel 11.

[0036] The water barrier wall 30 has side wall portions 30a, 30b, and 30c that are erected to surround the periphery of the control board when viewed in a plane, so that it can effectively block water such as rainwater from entering the upper space R3 above the control board 24.

[0037] The upper space R3 surrounded by the water-shielding wall 30 is hollow, and can be used as a working space when replacing the control board 24.

[0038] An access opening 30d is formed in the water barrier wall 30 on the front side of the housing 3, allowing access to the control board 24, so that the control board 24 can be replaced without accessing it from the top panel 11 side of the housing 3.

[0039] By forming vents 30b1 and 33 in the water impermeable wall 30 and the connecting member 32, which communicate with the fan chamber R2 in which the outdoor fan 5 is installed, a flow is formed from the upper space R3 above the control board 24 toward the outdoor fan 5. This makes it possible to suppress a rise in temperature of the control board 24.

[0040] The water shielding wall 30 is provided between the top plate 11 and the upper part of the partition plate 15 so as to receive the load, thereby improving the strength of the outdoor unit 1. In addition, since the water shielding wall 30 receives the load, a large load is not applied to the control box 20, and therefore to the control board 24.

[0041] The water shielding wall 30 is provided so as to avoid the path between the heat dissipation fins 24a provided on the control board 24 and the outdoor fan 5. This allows for a smooth flow of fluid from the heat dissipation fins 24a toward the outdoor fan 5, improving cooling efficiency.

[0042] The outdoor units described in the above-described embodiments can be understood, for example, as follows.

[0043] An outdoor unit (1) according to one embodiment of the present disclosure includes an outdoor fan (5) that introduces outside air, a compressor (13) that compresses a refrigerant, a control board (24) on which electrical components (24c) that control the outdoor fan and / or the compressor are mounted, a control box (20) that houses the control board, a housing (3) that houses the outdoor fan, the compressor, the control board, and the control box, and isolation members (30, 32) that isolate the control box from a top plate (11) of the housing so as to form a space (R3) between the control board and the top plate, and the control board is removable with the isolation member fixed to the housing side.

[0044] An isolation member is provided above the control box to create a space between it and the top plate. This ensures a working space above the control box, making it easier to replace the control board and perform other tasks. Furthermore, heat generated by the electrical components on the control board is dissipated into the space above, preventing the temperature of the electrical components from rising. The control board can be made removable with the isolation member fixed to the housing, so that when replacing the control board, the control board can be removed without removing the isolation member from the housing. The isolating member creates a space above the control box, i.e., above the control board, ensuring sufficient working space when replacing the control board. In particular, it makes it possible to access the control board from the front side of the housing without removing the top panel, which is advantageous when there is an obstacle above the top panel.

[0045] In the outdoor unit according to one aspect of the present disclosure, the isolation member includes side walls (30a, 30b, 30c) that stand upright so as to surround the periphery of the control board in plan view.

[0046] The isolation member has side walls that are erected to surround the periphery of the control board when viewed in a plane, and can therefore be used as a water-blocking wall to prevent water such as rainwater from entering the space above the control board.

[0047] In the outdoor unit according to one aspect of the present disclosure, the isolation member is formed on the front side of the housing and has an opening (30d) through which the control board can be accessed.

[0048] The isolation member has an opening formed on the front side of the housing, allowing access to the control board, so that the control board can be replaced without accessing it from the top panel side of the housing.

[0049] In the outdoor unit according to one aspect of the present disclosure, the space surrounded by the side wall portion is hollow.

[0050] The space surrounded by the side wall portion is hollow, and can be used as a working space when replacing the control board.

[0051] In the outdoor unit according to one aspect of the present disclosure, the isolation member is formed with a vent (30b1, 33) that communicates with the space in which the outdoor fan is provided.

[0052] By forming a vent in the isolation member that communicates with the space where the outdoor fan is installed, a flow of air is created from the space above the control board toward the outdoor fan, which makes it possible to suppress temperature increases in the control board.

[0053] In an outdoor unit according to one aspect of the present disclosure, a partition plate (15) that separates a fan chamber (R2) in which the outdoor fan is installed and a machine chamber (R1) in which the compressor is installed is erected upward from the bottom of the housing, and the isolating member is arranged to receive a load between the top plate and the upper part of the partition plate.

[0054] The isolation member is provided between the top plate and the upper part of the partition plate to support the load, improving the strength of the outdoor unit. In addition, because the isolation member supports the load, a large load is not applied to the control box, and therefore to the control board.

[0055] In the outdoor unit according to one aspect of the present disclosure, a heat dissipation fin (24a) is provided that is fixed to the control board, and the isolation member is provided to avoid a path between the heat dissipation fin and the outdoor fan.

[0056] Heat dissipation fins are fixed to the control board. The heat dissipation fins cool electrical components such as the CPU mounted on the board. The isolation member is installed to avoid the path between the heat dissipation fins and the outdoor fan. This allows for a smooth flow of fluid from the heat dissipation fins toward the outdoor fan, improving cooling efficiency. [Explanation of symbols]

[0057] 1 Outdoor unit 3. Housing 5 Outdoor fan 7 Fan Guard 9 Service Panel 10 Rear Panel 11 Top plate 12 Side Panel 13 Compressor 15 Divider 15a top end 16 Bottom plate 17 Outdoor heat exchanger 20 Control Box 22 Frame 22a Upper frame 22a1 seat 22b Bottom frame 22c Opening for heat dissipation fin 22d terminal block 22e Claw part 23 Bis 24 Control board 24a Heat dissipation fin 24b Board body 24c Electrical Parts 24d screw hole 26 Cover member 26a Main surface 26b Side 26b1 Protrusion 30 Water barrier (isolation member) 30a 1st side wall part 30a1 Connection piece 30b 2nd side wall part 30b1 Ventilation hole 30c 3rd side wall part 30c1 Connection piece 30d access opening 30f bottom end 32 Connection member (isolation member) 33 Ventilation R1 Machine room R2 Fan Room R3 upper space

Claims

1. An outdoor fan that introduces outside air; a compressor that compresses a refrigerant; a control board provided with electrical components for controlling the outdoor fan and / or the compressor; a control box that houses the control board; a housing that accommodates the outdoor fan, the compressor, the control board, and the control box; an isolation member isolating the control box from the top plate of the housing so as to form a space between the isolation member and the top plate; Equipped with the control board is removable with the isolation member fixed to the housing side, The isolation member is provided between the top plate and the control box of the outdoor unit.

2. The outdoor unit according to claim 1 , wherein the isolation member includes a side wall portion that stands upright so as to surround the periphery of the control board in a plan view.

3. The outdoor unit according to claim 2, wherein the space surrounded by the side wall portion is a cavity.

4. The outdoor unit according to any one of claims 1 to 3, wherein the isolation member is formed on the front side of the housing, and has an opening through which the control board can be accessed.

5. The outdoor unit according to any one of claims 1 to 4, wherein the isolation member is formed with a vent hole communicating with a space in which the outdoor fan is provided.

6. a partition plate that separates a fan chamber in which the outdoor fan is installed and a machine chamber in which the compressor is installed is provided upright from the bottom of the housing, The outdoor unit according to any one of claims 1 to 5, wherein the isolating member is provided so as to receive a load between the top plate and an upper portion of the partition plate.

7. a heat dissipation fin fixed to the control board; The outdoor unit according to any one of claims 1 to 6, wherein the isolating member is provided so as to avoid a path between the heat dissipating fin and the outdoor fan.

Citation Information

Patent Citations

  • JP1991052527U

  • Gate generating circuit, semiconductor measuring instrument, and semiconductor measuring method

    JP2001281286A

  • Outdoor unit of air conditioner

    JP2009097743A

  • Outdoor unit for air conditioner

    JP2011094926A