JP6714521B2 - Circuit board connection structure - Google Patents

Description

The present invention relates to a circuit board connection structure in which a circuit such as a switching power supply device is arranged on a printed board.

Conventionally, a printed circuit board of a switching power supply device converts an input voltage into an intermittent voltage by turning a switching element on and off, and then transmits the voltage to a rectifying/smoothing circuit including a secondary side rectifying element, a choke coil and a capacitor. A circuit component that converts the output voltage by rectifying and smoothing is arranged.

In such a switching power supply device, generally, circuit components are arranged on a printed circuit board and the components are connected to each other by soldering to a printed pattern. The positive and negative lines of the rectifying and smoothing circuit section on the side are provided with busbars capable of flowing a large current with low loss, and the busbars are arranged on the printed circuit board to take out positive and negative output terminals.

Further, as a circuit board connection structure of a smoothing circuit in a switching power supply device handling a large current, a conventional connection structure using only a bus bar without using a printed circuit board is known, for example, as shown in FIGS. 8 and 9. There is.

As shown in FIG. 8, the bus bars 120 and 121 as sheet metal wiring are laid substantially parallel to each other such that the bus bar 120 serves as a negative electrode side line of the output terminal and the bus bar 121 serves as a positive electrode side line of the output terminal. The connection terminal 105a of the choke coil 105 is connected to one end of the bus bar 121 with a screw.

The electrolytic capacitors 106, 107, 108 are mounted on the busbars 120, 121 via an insulating plate 140 as an insulator, and their lead terminals 106a, 107a, 108 have busbars as shown in the sectional view of FIG. Directly soldered to 120 and 121.

JP, 2006-202895, A

However, in the conventional connection structure shown in FIGS. 8 and 9, the electrolytic capacitor is directly soldered to the bus bar. However, in order to directly solder the component having a large heat capacity such as the bus bar, This requires advanced soldering technology and equipment, as well as a wide variety of production processes, which complicates the process of soldering printed circuit boards and prolongs the production lead time. Moreover, since an insulating plate is required, the number of parts is increased, and there is a problem that a screw tightening process is added.

To solve this problem, place the busbar and the smoothing capacitor separately on the printed circuit board, and pass the lead terminals of the busbar and the smoothing capacitor through the insertion holes of the printed circuit board to form the printed pattern on the opposite surface. Soldering is possible.

However, when the busbar and the capacitor are separately arranged on the printed circuit board, the space for each is required, and the wiring distance for connecting the busbar used as a large current output line and the capacitor increases. There is a problem that the wiring length becomes long, and the output voltage includes a ripple voltage waveform that sharply changes due to parasitic inductance.

INDUSTRIAL APPLICABILITY According to the present invention, when a bus bar and a circuit component such as a capacitor are arranged on a printed circuit board, an arrangement space can be reduced and downsized, and a wiring length between the bus bar and the circuit component can be shortened to improve electrical characteristics. It is an object of the present invention to provide a circuit board connection structure for

(Circuit board connection structure)
The present invention is a circuit board connection structure in which circuit components are arranged on a printed board using a bus bar,
The bus bar is closely attached to the board surface of the printed circuit board , and then the circuit components are sequentially stacked and arranged.
Lead terminals of the bus bar is inserted into the insertion hole of the printed circuit board are connected by soldering to the printed pattern on the substrate rear surface,
Lead terminals of the circuit component is connected by soldering to be inserted by inserting the formed openings in the bus bar insertion hole of the printed circuit board printed pattern on the substrate back surface without direct contact with the bus bar,
The bus bar and the circuit component are connected through a printed pattern on the back surface of the substrate .

(Capacitors as circuit components)
Circuit component is a capacitor.

(Circuit parts layout of switching power supply)
On the printed circuit board , circuit components of a switching power supply device having a capacitor are arranged.

(Arrangement structure of output terminals)
As a circuit component of the switching power supply device, a first output terminal member and a second output terminal member are further arranged on the printed circuit board,
The lead terminal of the first output terminal member is inserted into the insertion hole of the printed board through the opening hole formed in the busbar without directly contacting the busbar and is connected to the printed pattern on the back surface of the board by soldering,
One end of the second output terminal member is fixedly arranged on the surface of the printed circuit board while being in contact with the bus bar ,
The first output terminal member, the second output terminal member and the capacitor are connected via the bus bar and the printed pattern on the back surface of the substrate.

(Multiple capacitor arrangement)
Capacitor, a plurality of arranged on the substrate surface of the printed circuit board, are connected in parallel by soldering to the printed pattern on the substrate back surface.

(Ventilation passage for forced cooling)
The plurality of condensers are arranged in a plurality of rows in a predetermined direction, and an air passage through which cooling air from the cooling fan passes is formed between the plurality of condenser arrangement rows.

(Basic effect)
The present invention relates to a circuit board connection structure in which circuit components are arranged on a printed circuit board by using bus bars. In the circuit board connection structure, the bus bar and the circuit components are sequentially stacked on the substrate surface of the printed circuit board and extended from the bus bar. The lead terminal is inserted into the insertion hole of the printed circuit board and connected to the printed pattern on the back side of the board by soldering, and the lead terminal of the circuit component is inserted through the opening hole formed in the bus bar without contacting and the printed circuit board is inserted. Since it is inserted into the hole and connected to the printed pattern on the back side of the board by soldering, the bus bar and circuit components are stacked on the printed board, reducing the installation space and making it smaller than when they are placed separately. can do.

Further, by stacking the bus bar and the circuit component on the printed circuit board, the wiring length between the bus bar and the circuit component via the printed pattern can be shortened, and the electrical characteristics are improved.

Furthermore, since the bus bar and the circuit components are all connected to the printed board by soldering, there is no problem when soldering directly to the bus bar.

(Effects of placing capacitors as circuit components)
Further, the circuit component is a capacitor, and the bus bar and the capacitor are sequentially stacked on the board surface of the printed board, and the lead terminals extending from the bus bar are inserted into the insertion holes of the printed board to form the printed pattern on the back surface of the board. The lead terminals of the capacitor are inserted into the insertion holes of the printed circuit board without being touched through the opening holes formed in the bus bar and are connected to the printed pattern on the backside of the circuit board by soldering. By stacking the busbar and the capacitor on the board, the installation space can be reduced and the size can be reduced compared to the case where they are arranged separately, and the busbar and the capacitor can be stacked on the printed circuit board. Thus, the wiring length between the bus bar and the capacitor via the printed pattern can be shortened, and the electrical characteristics are improved.

(Effects of circuit component layout of switching power supply)
On the printed circuit board, the input voltage is converted to an intermittent voltage by turning the switching element on and off, and then transferred to a rectifying and smoothing circuit equipped with a rectifying element, a choke coil and a capacitor through a transformer, and the output voltage is rectified and smoothed. The circuit components of the switching power supply device that converts the power supply to the busbar are placed on the printed circuit board, and the capacitors for the rectifying and smoothing circuit are stacked on the busbar to reduce the installation space and reduce the size. The wiring length between the printed patterns between the two can be shortened, and the parasitic inductance component is reduced, thereby suppressing and removing the abrupt change in the ripple voltage that periodically occurs in the output voltage due to the parasitic inductance component. It is possible.

(Effect of output terminal layout)
Further, as a circuit component of the switching power supply device, a plus output terminal member and a minus output terminal member are further arranged on the printed circuit board, and the plus output terminal member is inserted into the opening formed in the bus bar without making contact with the printed board. Inserted into the insertion hole of the board and connected to the printed pattern on the back side of the board by soldering, the negative output terminal member was fixedly placed on the surface of the printed board while being in contact with the bus bar, so the bus bar and the positive output terminal were mounted on the printed board. Even if the members are stacked, the lead terminals provided on the positive output terminal member are inserted into the insertion holes of the printed board through the opening holes of the bus bar and soldered as in the case of the capacitor. The positive output terminal member can be laminated and arranged together with the capacitor on the bus bar arranged on the printed circuit board, and the arrangement space can be further reduced and the size can be reduced.

(Effects of arranging multiple capacitors)
In addition, because multiple capacitors are provided and connected in parallel by soldering to the printed circuit board, by placing multiple capacitors on the bus bar that is placed on the printed circuit board, the space for placing multiple capacitors can be increased. There is no need to separately secure the installation space, and the installation space is greatly reduced, enabling downsizing.

(Effect of the ventilation passage for forced cooling)
Further, the plurality of capacitors are arranged in a plurality of rows in a predetermined direction, and a ventilation path through which the cooling air from the cooling fan passes is formed between the plurality of rows of the plurality of condensers. Even if current flows and circuit parts including capacitors and bus bars generate heat, the cooling efficiency by forced air blowing from the cooling fan is high, and the operating temperature of the device or equipment using the printed circuit board connection structure of the present invention is reduced. , Which can improve reliability and durability.

Explanatory drawing showing a circuit board connection structure in which a transformer secondary side circuit of a switching power supply device is mounted Circuit diagram showing a power conversion unit of a switching power supply device including the secondary circuit of the transformer of FIG. Explanatory drawing which decomposed|disassembled and showed the circuit board connection structure of FIG. An explanatory view showing an embodiment of a circuit board connection structure by taking out the capacitor side of FIG. Explanatory drawing which expanded and showed the laminated structure of the bus bar and the positive output terminal with respect to the printed circuit board in FIG. Explanatory drawing showing a laminated structure of a printed circuit board, a bus bar, and a capacitor in FIG. Explanatory drawing showing the voltage waveform that appears between the output terminals of the switching power supply Explanatory drawing showing a conventional connection structure in which capacitors are arranged on a bus bar via an insulating plate Explanatory drawing showing the connection structure of FIG. 8 in section

(Outline of circuit board contact structure)
FIG. 1 is an explanatory diagram showing a circuit board connection structure in which a transformer secondary side circuit of a switching power supply device is mounted.

As shown in FIG. 1, a transformer 12, a rectifying element 14, a choke coil 16 and a capacitor 18 provided in a transformer secondary side circuit of a switching power supply device are arranged on the substrate surface of a printed circuit board 10.

The transformer 12 has a transformer output terminal 28 on the right side, and a bus bar 20 is disposed on the substrate surface between the transformer output terminal 28 and the rectifying element 14, and the transformer output terminal 28 and the rectifying element 14 are interposed via the bus bar 20. Are connected.

A plurality of rectifying elements 14 are arranged in a bus bar 22 formed in a box shape, and a positive output terminal 24 is taken out from the bus bar 22. Further, a plurality of capacitors 18 are arranged in two rows in the depth direction following the bus bar 22 in which the rectifying elements 14 are housed, and the minus output terminal 26 is taken out from the substrate on the left side of the row of the capacitors 18.

The choke coil 16 takes out the choke coil terminal 30 on the right side, and the choke coil terminal 30 is also connected to the rectifying element 14 side via another bus bar 20 arranged on the substrate.

(Switching power supply circuit)
Figure 2 is a circuit diagram showing a power converting unit of the switching power supply comprising a transformer secondary circuit of FIG. 1, taking a single-ended de head forward converter as an example.

As shown in FIG. 2, in the circuit of the switching power supply device, the switching element 11 is connected in series to the primary winding 12a of the transformer 12, and the secondary winding 12b of the transformer 12 is provided with a diode 14a, 14b. A circuit section and a smoothing circuit section including a choke coil 16 and a capacitor 18 are provided.

The switching element 11 is turned on/off by a control circuit (not shown), and generates an intermittent voltage in the secondary winding 12b via the transformer 12 after converting the input voltage into an intermittent voltage by turning on/off the switching element 11. The intermittent voltage generated in the secondary winding 12b of the transformer 12 is rectified by the diodes 14a and 14b, smoothed by the choke coil 16 and the capacitor 18, and converted into a DC output voltage.

Operation of the transformer secondary circuit of the single-ended de head forward method is a choke coil 16 by the voltage generated in the secondary winding 12b of the transformer 12 by turning on the switching element 11, a solid line arrow a capacitor 18 and a diode 14a A forward current flows through the path shown in the figure, electric charge is stored in the capacitor 18 and energy is stored in the choke coil 16, and when the switching element 11 is turned off, the energy stored in the choke coil 16 causes the capacitor 18 and the diode 14b to pass through the choke coil 16. The flywheel current flows through the path indicated by the dotted arrow, which causes the intermittent voltage to be rectified and smoothed.

Here, the rectifying diodes 14a and 14b provided in the secondary circuit of the transformer of FIG. 2 correspond to the rectifying element 14 of FIG. 1. In FIG. 1, a plurality of rectifying elements 14 should be connected in parallel. Thus, the functions of the diodes 14a and 14b in FIG. 2 are realized. Further, in FIG. 1, the capacitor 18 of FIG. 2 is realized by connecting eight capacitors 18 in parallel.

(Outline of circuit parts and bus bar)
FIG. 3 is an explanatory view showing the circuit board connection structure of FIG. 1 in an exploded manner. As shown in FIG. 3, in the present embodiment, the bus bar 20 is divided into three pieces and arranged on the substrate of the printed board 10.

Here, the front bus bar 20 is used to connect the transformer 12 and the rectifying element, the central bus bar 20 is used to connect the transformer 12 and the choke coil 16 to the rectifying element, and the rear bus bar 20 is used to connect the choke coil 16 to the rectifying element. And used to connect capacitors.

(Details of circuit board contact structure)
FIG. 4 is an explanatory view showing an embodiment of a circuit board connection structure by taking out a portion of the mounting structure on the capacitor side of FIG.

As shown in FIG. 4, the bus bar 20 is arranged on the substrate surface of the printed circuit board 10, and four capacitors 18 are arranged on the bus bar 20 in two rows of four capacitors. In addition, the positive output terminal 24 extending from the bus bar 22 is taken out from between the capacitors 18 arranged in two rows, and the row of the transformers 12 and the choke coil 16 and the capacitors 18 are arranged. A minus output terminal 26 is arranged on the surface of the substrate between the rows and is taken out to the outside.

FIG. 5 is an explanatory view showing an enlarged laminated structure of the bus bar and the positive output terminal on the printed circuit board in FIG. As shown in FIG. 5, an insertion hole 36 is formed in the printed circuit board 10, and a lead terminal 38 extending from the bus bar 20 is inserted into the insertion hole 36 so that it can be connected to a printed pattern on the back surface of the printed circuit board by soldering. ..

Further, two opening holes 32 and 34 are formed adjacent to each other at a position where the capacitor 18 of the bus bar 20 is laminated, and two lead terminals from the capacitor 18 are individually passed through the opening holes 32 and 34. It can be inserted into the insertion hole of the printed circuit board 10 without contacting the bus bar 20. The opening holes 32 and 34 for passing the lead terminals of the capacitor 18 have different diameters according to the size of the lead terminal extraction portion so that the lead terminals do not come into contact with the bus bar 20 reliably.

Further, an opening hole 40 is formed at a position where the plus output terminal 24 is stacked and arranged on the bus bar 20, and the lead terminal 42 formed at the lower end of the plus output terminal 24 is passed through the opening hole 40 without contacting the bus bar 20. Is inserted into the insertion hole of the printed circuit board 10 and can be connected to the printed pattern on the back surface of the printed circuit board by half-bonding.

FIG. 6 is an explanatory view showing a laminated structure of a printed circuit board, a bus bar and a capacitor in a cross section, FIG. 6(A) shows the cross sectional structure, and FIG. 6(B) shows a current path.

As shown in FIG. 6A, in the circuit board connection structure according to the present embodiment, the bus bar 20 and the capacitor 18 are sequentially laminated and arranged on the surface of the printed board 10. The lead terminal 38 extending from the bus bar 20 is inserted into the insertion hole 36 of the printed board 10 and connected to the printed pattern on the back surface of the board by soldering.

In addition, one lead terminal 44 of the capacitor 18 is inserted into the insertion hole 46 of the printed circuit board 10 without passing through the opening hole 34 formed in the bus bar 20, and is connected to the printed pattern on the back surface of the substrate by soldering. To be done. The other lead terminal 44 of the capacitor 18 is inserted into the insertion hole of the printed circuit board 10 without contacting the opening hole 32 formed in the bus bar 20 shown in FIG. 5 and soldered to the printed pattern on the back surface of the printed circuit board. Connected by.

In addition, the lead terminal 42 formed at the lower end of the plus output terminal 24 is inserted into the insertion hole 48 of the printed circuit board 10 without passing through the opening hole 40 formed in the bus bar 20, and the printed pattern on the back surface of the substrate. Is connected by soldering.

Further, the minus output terminal 26 is erected and fixed on the printed circuit board 10 while being in contact with the bus bar 20, so that the bus bar 20 has a negative potential.

According to such a circuit board connection structure, the capacitor 18 is laminated and arranged on the bus bar 20 arranged on the printed circuit board 10, so that the space for disposing the bus bar 20 and the capacitor 18 on the board surface of the printed circuit board 10. It is no longer necessary to separately secure each of them, and the space for disposing the bus bar 20 and the capacitor 18 is shared, so that the circuit board connection structure is downsized, and a switching power supply device using the printed circuit board 10 having this circuit board connection structure is provided. Can be miniaturized.

(Reduction of track length)
As shown in FIG. 6A, the capacitors 18 are laminated on the busbars 20 arranged on the printed circuit board 10, so that the lead terminals 44 of the capacitors 18 and the busbars 20 via the print pattern are included. The distance of the connection wiring between the positive output terminal 24 and the negative output terminal 26 can be shortened.

FIG. 6B shows a current path of the circuit board connection structure in which the capacitor 18 is laminated and arranged on the bus bar 20 arranged on the printed board 10, and as shown by an arrow,
A current flows through a path of (plus output terminal 24)→(back side print pattern of printed circuit board 10)→(capacitor 18)→(bus bar 20)→(choke coil 16).

In such a current path, the lead terminal 42 of the positive output terminal 24 and the negative output terminal 26 are provided on the back surface of the printed circuit board 10 at positions substantially the same distance on both sides from the two lead terminals 44 of the capacitor 18. And the lead terminal 38 of the bus bar 20 which is a negative output line in contact with the positive output terminal 24 are located between the lead terminal 42 of the positive output terminal 24 and one lead terminal 44 of the capacitor 18. 2 corresponds to the wiring length of the dotted line portion a from the plus terminal of the capacitor 18 to the plus output line, and the length of the print pattern between the lead terminal 38 of the bus bar 20 and the other lead terminal 44 of the capacitor 18. Lb corresponds to the wiring length of the dotted line portion b from the negative terminal of the capacitor 18 shown in FIG. 2 to the negative output line.

FIG. 7 is an explanatory diagram showing a voltage waveform appearing between the output terminals of the switching power supply device, FIG. 7(A) shows a defective voltage waveform, and FIG. 7(B) shows an ideal voltage waveform. There is.

In the switching power supply device shown in FIG. 2, the intermittent voltage generated by turning on and off the switching element 11 is transmitted to the secondary side of the transformer 12 for rectification and smoothing, and the output voltage is several μsec to several tens of seconds. A ripple voltage waveform having a period of μsec is superimposed.

In the ripple voltage superimposed on the voltage waveform shown in FIG. 7A, when viewed from the center line, there is a portion in which the voltage waveform changes abruptly at the switching timing of the rising period and the falling period of the voltage waveform. Yes, the difference between the upper limit and the lower limit of the output voltage waveform is large.

The voltage that changes abruptly in this way is generated by the current flowing in the parasitic inductance component generated in the wiring of the dotted line portions a and b on both sides of the capacitor 18 in FIG. 2, and the larger the flowing current is, the more remarkable it is. It is a characteristic that appears in.

For this reason, when handling a large current in the switching power supply device, it is desirable to shorten the connection wiring of the dotted line portions a and b in FIG. 2 as much as possible to reduce the parasitic inductance component.

In the circuit board connection structure of the present embodiment, as shown in the current path of FIG. 6B, the lead terminal 42 of the positive output terminal 24 and the capacitor 18 corresponding to the wiring connection of the dotted line portion a of FIG. The length La of the printed pattern between one of the lead terminals 44 and the printed pattern between the lead terminal 38 of the bus bar 20 and the other lead terminal 44 of the capacitor 18 corresponding to the wiring connection of the dotted line portion b in FIG. The length Lb is shortened by the capacitor 18 being laminated on the bus bar 20 arranged on the printed circuit board 10. Therefore, the parasitic inductance component due to the connection wiring on both sides of the capacitor 18 is reduced. , The ideal voltage waveform of FIG. 7B can be approximated.

(Capacitor layout structure for transformer and cho coil)
In the circuit board connection structure of the present embodiment, as shown in FIG. 1, a plurality of capacitors 18 are used, and in this case, the plurality of capacitors 18 are arranged in the arrangement direction of the transformer 12 and the choke coil 16. For example, four pieces are arranged in two rows in the same direction.

In this way, the plurality of capacitors 18 are arranged in parallel in two rows with respect to the arrangement of the transformer 12 and the choke coil 16 and are arranged at the same distance, so that the plurality of capacitors 18 with respect to the printed circuit board 10 can be efficiently arranged in a small space. The size of the switching power supply device can be reduced.

Further, between the row of the transformers 12 and the choke coils 16 and the row of the plurality of capacitors 18 arranged in the same direction shown in FIG. 1 is formed as a ventilation path through which the wind by forced cooling from a cooling fan (not shown) passes. There is.

Therefore, even if a large current flows through the output circuit section of the switching power supply device and the circuit components including the capacitor 18 generate heat, the cooling efficiency is high due to the forced air blowing from the cooling fan, so that the operating temperature is reduced and the reliability is improved. And durability can be improved.

[Modification of the present invention]
The above-described embodiment exemplifies a circuit board connection structure in which circuit components of the switching power supply device are arranged and connected to a printed circuit board, but the present invention is not limited to this, and an appropriate circuit component can be provided by using a bus bar on the printed circuit board. For all the circuit board connection structures that have been placed, the bus bar and circuit components are sequentially stacked on the board surface of the printed board, and the lead terminals extending from the bus bar are inserted into the insertion holes of the printed board. It is connected to the printed pattern on the back side of the board by soldering, and the lead terminals of the circuit parts are inserted into the insertion holes of the printed board without passing through the opening holes formed in the bus bar and soldered to the printed pattern on the back side of the board. It includes a circuit board connection structure connected by.

Further, the above embodiments have taken single-ended de head forward converter as an example, in addition to this, the flyback converter, a full bridge converter, a half bridge converter may be a push-pull converter or the like.

Further, although the diode is used as the rectifying element in the secondary circuit of the transformer of the above embodiment, a synchronous rectifying circuit may be configured. In this case, instead of the rectifying element, a MOS-FET or the like may be used. A synchronous rectification element is used.

Further, the present invention includes appropriate modifications that do not impair the objects and advantages thereof, and is not limited by the numerical values shown in the above embodiments.

10: printed circuit board 12: transformer 14: rectifying element 16: choke coil 18: capacitors 20, 22: bus bar 24: positive output terminal 26: negative output terminal 28: transformer output terminal 30: choke coil terminals 32, 34, 40: openings Holes 36, 46, 48: Insertion holes 38, 42, 44: Lead terminals

Claims (6)

A circuit board connection structure in which circuit components are arranged using a bus bar on a printed circuit board,
The bus bar is closely attached to the substrate surface of the printed circuit board , and then the circuit components are sequentially laminated and arranged,
Lead terminals of the bus bars, wherein is inserted into the printed circuit board insertion hole are connected by soldering to the printed pattern on the substrate rear surface,
Lead terminals of the circuit component is connected by soldering to the substrate rear surface of the printed pattern by inserting the formed openings in the bus bar is inserted into the insertion hole of the printed substrate without direct contact with the bus bar ,
A circuit board connection structure, wherein the bus bar and the circuit component are connected via a printed pattern on the back surface of the board.
In the circuit board connection structure according to claim 1,
The circuit board connection structure , wherein the circuit component is a capacitor.
The circuit board connection structure according to claim 2,
The printed circuit board, the circuit board characterized in that the circuit components of the switching power supply device having the capacitor is arranged connecting structure.
The circuit board connection structure according to claim 3,
As a circuit component of the switching power supply device, a first output terminal member and a second output terminal member are further arranged on the printed circuit board,
Lead terminals of the first output terminal member is soldered to the substrate rear surface of the printed pattern by inserting the formed openings in the bus bar is inserted into the insertion hole of the printed substrate without direct contact with the bus bar Connected by
One end of the second output terminal member is fixedly arranged on the surface of the printed circuit board while being in contact with the bus bar ,
A circuit board connection structure, wherein the first output terminal member, the second output terminal member, and the capacitor are connected via the bus bar and the printed pattern on the back surface of the board.
The circuit board connection structure according to any one of claims 2 to 4 ,
A circuit board connection structure , wherein a plurality of the capacitors are arranged on a front surface of the printed board and are connected in parallel to a printed pattern on the back surface of the board by soldering.
The circuit board connection structure according to claim 5,
The circuit board connection structure, wherein the plurality of capacitors are arranged in a plurality of rows in a predetermined direction, and an air passage for passing cooling air from a cooling fan is formed between the plurality of rows of the plurality of condensers.

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