Technical Field
[0001] The present invention relates to an outdoor unit of an air conditioner having a heat
sink for efficiently cooling a power module as an electronic component for driving
and controlling the air conditioner.
Background Art
[0002] An outdoor unit of an air conditioner in the related art has a structure in which
an electric component box is provided along a partition plate for dividing the interior
of the outdoor unit into a machinery chamber and a heat exchanger chamber, and in
order to cool a power module on an electronic substrate provided in the electric component
box, a heat radiation fin is projected from the heat exchanger chamber side of the
electric component box, a heat sink is provided at an angle such that the longitudinal
direction of the heat radiation fin extends vertically with respect to a heat exchanger
on the back surface side of the outdoor unit, and an angular U-shaped wind direction
guide is provided on the heat radiation fin. The angular U-shaped wind direction guide
keeps a constant space with the heat sink, and is mounted in such a manner that an
upstream side thereof projects toward the heat exchanger and a downstream side thereof
is opened (for example, Patent Literature 1).
[Prior Art]
[Patent Literature]
Summary of Invention
Technical Problem
[0004] In an outdoor unit of an air conditioner in the related art, a heat sink can not
be arranged along a main stream of air taken through a heat exchanger and blown to
outdoor from a blowout port on a front surface of the outdoor unit. Therefore, only
a small part of the whole air taken from the heat exchanger flows into the heat sink,
and hence the volume of the air passing through a heat radiation fin of the heat sink
is not sufficient. Consequently, a cooling efficiency of the heat sink is low.
Therefore, for example, under the circumstance of a high-load operation for the power
module such as a case where a user operates the air conditioner to perform a cooling
operation when the outside temperature is high, sufficient cooling of a power module
cannot be achieved and, consequently, breakdown of the power module due to heat rupture
may occur, and remarkable impairment of reliability is resulted.
In addition, in the outdoor unit of the air conditioner in the related art, since
the cooling efficiency of the power module is low, there is the need to upsize the
heat sink or to select expensive electronic part elements which resist the heat rupture
in order to ensure operation reliability. These factors become contributor to the
growing manufacturing cost or increase in weight.
[0005] In order to solve the above-described problems, it is an object of the present invention
to provide an outdoor unit of an air conditioner in which breakdown of a power module
due to heat rupture is prevented by achieving efficient cooling of a heat sink being
configured to cool the power module and having heat radiation fins provided so as
to project from one of side surfaces of an electric component box toward a heat exchanger
chamber, whereby high operation reliability is ensured.
Solution to Problems
[0006] An outdoor unit of an air conditioner according to the present invention including:
a partition plate provided so as to extend upright from a bottom plate of the outdoor
unit to halfway to a top thereof;
an electric component box placed on the partition plate and configured to divide the
interior of the outdoor unit into a machinery chamber and a heat exchanger chamber
in cooperation with the partition plate;
an electronic substrate stored in the electric component box and having a power module
mounted thereon;
a compressor provided in the machinery chamber;
a propeller fan driven by a fan motor and a heat exchanger provided in the heat exchanger
chamber; and
an electric component partition plate being in contact at one end thereof with an
end of the heat exchanger positioned on the side of a back surface of the heat exchanger
chamber and at the other end thereof with a front plate of the outdoor unit, and configured
to divide the interior of the electric component box and the heat exchanger chamber,
wherein
the electric component partition plate is inclined so that an extended line thereof
toward a front surface of the outdoor unit intersects a line of projection of a front
edge of a vane of the propeller fan,
the electronic substrate is fixed to an opening provided on the electric component
partition plate so as to be positioned within the electric component box and a heat
sink for cooling the power module is fixed in parallel to a surface of the electric
component partition plate in contact with the back side of the electronic substrate,
and
a plurality of heat radiation fins are provided on one surface of the heat sink so
as to project toward the heat exchanger chamber and extend in parallel to a flow of
air on the electric component partition plate.
Advantageous Effect of the Invention
[0007] According to the outdoor unit of the air conditioner in the present invention, the
electric component partition plate, being in contact at the one end thereof with the
end of the heat exchanger positioned on the side of the back surface of the heat exchanger
chamber and at the other end thereof with the front plate of the outdoor unit and
being configured to divide the interior of the electric component box and the heat
exchanger chamber, is inclined so that the extended line thereof toward the front
surface of the outdoor unit intersects a line of projection of the front edge of a
vane of the propeller fan, the electronic substrate is fixed to the opening provided
on the electric component partition plate so as to be positioned within the electric
component box and the heat sink for cooling the power module is fixed in parallel
to the one surface of the electric component partition plate in contact with the back
side of the electronic substrate, and the plurality of heat radiation fins are provided
on the one surface of the heat sink so as to project toward the heat exchanger chamber
and extend in parallel to the flow of the air on the electric component partition
plate. Therefore, the invention has advantages as follows. The heat radiation fins
of the heat sink are capable of capturing a main stream of the air, and the speed
of the air passing through the heat radiation fins may be increased. In addition,
since the air flowing inward from an inlet port of the heat sink reaches an outlet
port without leaving the heat sink at some midpoint and escaping therefrom, and generation
of significant wind drift in an air duct of the outdoor unit is prevented, a pressure
loss in the air duct is reduced, and a cooling efficiency of the heat sink is enhanced
by being capable of increasing the air volume in the entire outdoor unit, so that
operation reliability of the air conditioner is enhanced by preventing breakdown due
to heat rupture of the power module.
Also, since the cooling can be achieved sufficiently even with the heat sink having
a smaller volume than that in the related art by increasing the air volume of the
entire outdoor unit, reduction of the manufacturing cost and reduction of the weight
of the outdoor unit are achieved.
Furthermore, since the cooling efficiency of the heat sink can be enhanced, a power
module which is low in heat resistance and required lower cost than in the related
art can be employed. From this point of view as well, the reduction of the manufacturing
cost is effectively achieved. Brief Description of Drawings
[0008]
Fig. 1 is a plan view of an outdoor unit of an air conditioner according to Embodiment
1 of the present invention, viewed from the top.
Fig. 2 is an explanatory drawing showing a partition plate and an electric component
partition plate viewed in the direction indicated by an arrow X in Fig. 1.
Fig. 3 is a plan view showing a principal portion of the outdoor unit of the air conditioner
with a particular emphasis on an electric component box.
Fig. 4 is a perspective view of the outdoor unit of the air conditioner viewed obliquely
from the front.
Fig. 5 is a graph showing a relation between the position of a point of intersection
c between an extension of the electric component partition plate and a line of projection
of a front edge of a vane in the outdoor unit of the air conditioner and the wind
speed in a heat sink.
Fig. 6 is a schematic plan view showing a state of Arrangement 1 of a case where an
angle of inclination α of the electric component partition plate in the outdoor unit
of the air conditioner is narrow.
Fig. 7 is a schematic plan view showing a state of Arrangement 2 of a case where the
angle of inclination α of the electric component partition plate in the outdoor unit
of the air conditioner is wide.
Fig. 8 is a plan view of an outdoor unit of an air conditioner according to Embodiment
2, viewed from the top.
Fig. 9 is a cross-sectional view showing an electric component box and a heat sink
in the outdoor unit of the air conditioner.
Fig. 10 is a perspective view showing the heat sink and a wind direction guide in
the outdoor unit of the air conditioner.
Description of Embodiments
Embodiment 1
[0009] Fig. 1 is a plan view of an outdoor unit of an air conditioner according to Embodiment
1 when viewed from a top, Fig. 2 is an explanatory drawing showing a partition plate
and an electric component partition plate viewed in the direction indicated by an
arrow X in Fig. 1, Fig. 3 is a plan view showing a principal portion of the outdoor
unit of the air conditioner with a particular emphasis on an electric component box,
Fig. 4 is a perspective view of the outdoor unit of the air conditioner viewed obliquely
from the front, Fig. 5 is a graph showing a relation between the position of a point
of intersection c between an extension of the electric component partition plate and
a line of projection of the electric component partition plate and a front edge of
a vane in the outdoor unit of the air conditioner and the wind speed in a heat sink,
Fig. 6 is a schematic plan view showing a state of Arrangement 1 of a case where an
angle of inclination α of the electric component partition plate in the outdoor unit
of the air conditioner is narrow, and Fig. 7 is a schematic plan view showing a state
of Arrangement 2 of a case where the angle of inclination α of the electric component
partition plate in the outdoor unit of the air conditioner is wide.
[0010] In the drawings, an outdoor unit 1 of the air conditioner has a configuration in
which the interior of the outdoor unit is divided into a machinery chamber M and a
heat exchanger chamber H by a partition plate 3 formed of a sheet metal extending
upright from a bottom plate 2 to halfway to a top thereof and an electric component
box 14 placed on the partition plate 3.
The machinery chamber M includes a compressor 4 and the like for compressing a refrigerant
to a high-temperature high-pressure state. A heat exchanger 5 for performing heat
exchange between the refrigerant compressed to high-temperature and high-pressure
by the compressor 4 and the outdoor air, a propeller fan 6 for blowing air to the
heat exchanger 5 for promoting the heat exchange in the heat exchanger 5, and a fan
motor 7 for rotating the propeller fan 6 are provided in the heat exchanger chamber
H when the air conditioner is in a cooling operation.
A front plate 8 which constitutes the outdoor unit 1 is provided with a horn-shaped
bell mouth 10 so as to project toward the propeller fan. The bell mouth 10 is configured
to rectify air blown out from a blowout port 9 being opened in the front plate 8,
and is arranged outside the propeller fan 6 so as to keep a constant distance from
the propeller fan 6.
[0011] The propeller fan 6 has a structure having a plurality of curved vanes formed integrally
around a hub 11, and a portion of the vane on the side of a front surface of the outdoor
unit is referred to as a front edge of a vane 12. The propeller fan 6 is fixed at
a center of the hub 11 to a shaft of the fan motor 7. The rotation of the propeller
fan 6 in association with driving of the fan motor 7 generates a flow of air in the
interior of the heat exchanger chamber H in the outdoor unit 1.
Provided in the interior of the electric component box 14 mounted on the partition
plate 3 is an electronic substrate 13 and the like having a power module mounted thereon.
One end of an electric component partition plate 15 which forms a surface of the electric
component box 14 and divides the interior of the electric component box 14 and the
heat exchanger chamber H is in contact with an end of the heat exchanger 5 on the
side of a back surface of the heat exchanger chamber H, and the other end thereof
is in contact with the front plate 8, so that the electric component box 14 is secured
to the heat exchanger 5 and the front plate 8 by screws or the like.
[0012] The electric component partition plate 15 is arranged so that a surface on the side
of a back surface of the outdoor unit forms an angle of inclination α with respect
to the heat exchanger 5. The angle of inclination α of the electric component partition
plate 15 is an angle falling within a range which allows an extended line A, being
an extended line of the electric component partition plate 15 toward the front surface
of the outdoor unit, to intersect the line of projection B of the front edge of a
vane 12 of the propeller fan 6 on the side of the electric component box projecting
from the top of the outdoor unit.
In other words, the angle of inclination α is an angle which allows the point of intersection
c between the extended line A of the electric component partition plate 15 extending
toward the front surface of the outdoor unit and the line of projection B of the front
edge of a vane 12 to fall within a range from an end point d of the hub 11 to an outer
diameter point e of the front edge of a vane 12 of the propeller fan 6 on the side
of the electric component box.
The electric component partition plate 15 is bent into an elbow shape at a midpoint
toward inside the electric component box so as to avoid interference with the propeller
fan 6 and the bell mouth 10, and is fixed at the end thereof to the front plate 8.
[0013] The electric component partition plate 15 is provided with an opening, and the electronic
substrate 13 having the power module or the like for driving and controlling the compressor
4 and the fan motor 7 is fitted and fixed to the opening so as to be positioned inside
the electric component box.
In addition, a heat sink 17 for cooling the power module, which includes a plurality
of heat radiation fins 16 provided upright on one surface thereof, is attached to
the opening of the electric component partition plate 15 in parallel to a front surface
of the electric component partition plate 15 with screws or the like so as to be in
contact with the back side of the electronic substrate 13.
The plurality of heat radiation fins 16 of the heat sink 17 project toward the heat
exchanger chamber side of the electric component partition plate 15, and are arranged
with intervals in the vertical direction toward the bottom plate 2 when viewed from
the ceiling of the outdoor unit. The heat sink 17 and the plurality of heat radiation
fins 16 are arranged so as to extend in parallel to a flow of the air on the electric
component partition plate 15.
The heat sink 17 for cooling the power module, which includes the plurality of heat
radiation fins 16 on one surface thereof, is molded by an extrusion method or the
like using a metal having a high thermal conductivity such as aluminum as a material
in order to prevent the temperature of the power module from exceeding a heat resistant
temperature and causing damages and breakdown.
[0014] Subsequently, an operation of the outdoor unit 1 of the air conditioner in Embodiment
1 will be described.
Air taken by the rotation of the propeller fan 6 from the back surface of the outdoor
unit is subjected to the heat exchange with respect to the refrigerant in the heat
exchanger 5, passes through the spaces among the plurality of vanes of the propeller
fan 6 or a space between the propeller fan 6 and the bell mouth 10, and is blown out
from the blowout port 9 of the front plate 8 of the outdoor unit.
At this time, part of the air taken through the heat exchanger 5 flows from an inlet
port of the heat sink 17 smoothly along the electric component partition plate 15
without meandering significantly, passes through the plurality of heat radiation fins
16 arranged in parallel to the flow of air on the electric component partition plate
15 without allowing the air escaping from a midsection of the heat sink 17, and is
blown out from an outlet port of the heat sink 17, so that the heat sink 17 is cooled,
and the power module on the electronic substrate 13, which is in contact with the
heat sink 17, is also cooled.
[0015] As described thus far, the electric component partition plate 15 is provided in such
a manner that the point of intersection c between the extended line A of the electric
component partition plate 15 extending toward the front surface of the outdoor unit
and the line of projection B of the front edge of a vane 12 of the propeller fan 6
on the side of the electric component box falls within the range from the end point
d of the hub 11 on the line of projection to the outer diameter point e of the front
edge of a vane 12 of the propeller fan 6 on the side of the electric component box,
the plurality of heat radiation fins 16 of the heat sink 17 are arranged at intervals
in the vertical direction toward the bottom plate 2 when viewed from the top of the
outdoor unit, and the plurality of heat radiation fins 16 are arranged in parallel
to the flow of the air on the electric component partition plate 15. Therefore, advantages
described from (1) to (5) are achieved.
[0016] (1) Since the heat sink 17 having the plurality of heat radiation fins 16 can be
arranged along a main stream of the air flowing from the heat exchanger 5 to the blowout
port 9 of the front plate 8, the heat radiation fins 16 of the heat sink 17 are capable
of capturing the main stream of the air at high flow velocities.
Consequently, the flow speed of the air passing through the heat radiation fins 16
is higher than in the related art, so that a cooling efficiency of the heat sink 17
is enhanced. In order to prove this advantage, a result of measurement of wind velocities
at the inlet port and the outlet port of the heat sink 17 with a several different
angles of inclination α of the electric component partition plate 15 is shown in the
graph in Fig. 5.
[0017] Fig. 5 is the graph showing flow velocities at the inlet port and the outlet port
of the heat sink 17 and average flow velocities of the inlet port and the outlet port
with respect to the position of the point of intersection c between the extended line
A of the electric component partition plate 15 and the line of projection B of the
front edge of a vane 12, in which the lateral axis shows from the axial center of
the propeller fan 6 as an original point 0 to an end point of the blowout port 9 on
the side of the electric component box as 0.6.
As shown in Fig. 5, when the point of intersection c falls within the range from the
end point d of the hub 11 to the outer diameter point e of the front edge of a vane
12, high wind speeds not lower than 1.8 m
3/min in average of the wind velocities at the inlet port and the outlet port of the
heat sink 17 are obtained and, specifically, when the point of intersection c is at
the position of 0.45, a highest wind speed is obtained and hence the highest cooling
efficiency of the heat sink 17 is expected.
In contrast, in the case of Arrangement 1 in which the angle of inclination α of the
electric component partition plate 15 is small and the point of intersection c is
positioned on the side of the axial center of the propeller fan 6 with respect to
the end point d of the hub 11 as shown in FIG. 6, the average velocity of the wind
passing through the heat sink 17 is lowered in comparison with the case where the
point of intersection c falls within the range from the point d to the point e.
[0018] It is because if the angle α of inclination of the electric component partition plate
15 is small, the air flowing along the electric component partition plate 15 is caused
to meander significantly at a portion of the electric component partition plate 15
bent into an elbow shape to increase the pressure loss in an air duct as shown by
a typical flow of the air taken through the heat exchanger 5 as indicated by an arrow
in a broken line in Fig. 6.
In contrast, in the case of Arrangement 2 in which the angle α of inclination of the
electric component partition plate 15 is large, and the intersection c is positioned
on the side of the electric component box with respect to the outer diameter point
e of the propeller fan 6 as shown in FIG. 7, the average velocity of the air passing
through the heat sink 17 is lowered and the air speed on the side of the outlet port
of the heat sink 17 is significantly lowered in comparison with the case where the
intersection c falls within the range from the point d to the point e. It is because
the air flowing in from the inlet port of the heat sink 17 leaves the heat radiation
fins 16 on the way and escapes therefrom.
[0019]
(2) Since the electric component partition plate 15 and the heat sink 17 can be arranged
along the flow of the air flowing in the outdoor unit 1, the air flowing inward from
the inlet port of the heat sink 17 is prevented from leaving the heat sink 17 at some
midpoint and escaping therefrom, and reaches the side of the outlet port, and hence
the heat exchange can be performed using the entire heat radiation fins 16 of the
heat sink 17 effectively. Threfore, the cooling efficiency of the heat sink 17 is
enhanced.
(3) With the advantages described in (1) and (2) described above, even under the circumstance
of a high-intensity operation for the power module, such as a case where a user operates
the air conditioner to perform a cooling operation when the outside temperature is
high, damages or breakdown of the power module due to excessive heating is prevented,
and high operation reliability of the air conditioner can be obtained.
[0020]
(4) Since the cooling effect of the heat sink 17 is enhanced, the power module can
be cooled sufficiently even with the heat sink 17 having a smaller volume than that
in the related art. Therfore, reduction of manufacturing cost and reduction of the
weight of the outdoor unit 1 are achieved.
(5) Since the air flowing in the outdoor unit 1 of the air conditioner is prevented
from meandering significantly in the midpoint and hence causes a wind drift in the
air duct, the pressure loss in the air duct is restrained to a low level. Therefore,
the volume of air taken through the heat exchanger 5 is increased, the heat exchange
between the refrigerant and the air performed in the heat exchanger 5 is accelerated,
and the cooling performance and the heating performance of the air conditioner can
be improved.
Embodiment 2
[0021] Fig. 8 is a plan view of an outdoor unit of an air conditioner according to Embodiment
2 when viewed from the top, Fig. 9 is a cross-sectional view showing an electric component
box and a heat sink in the outdoor unit of the air conditioner, and Fig. 10 is a perspective
view showing the heat sink and a wind direction guide in the outdoor unit of the air
conditioner.
In Embodiment 1, the electric component partition plate 15 is provided at the angle
of inclination α which allows the point of intersection c between the extended line
A of the electric component partition plate 15 extending toward the front surface
of the outdoor unit and the line of projection B extending toward the propeller fan
6 on the side of the electric component box to fall within the range between the end
point d of the hub 11 on the line of projection B and the outer diameter point e of
the front edge of a vane 12, the plurality of heat radiation fins 16 of the heat sink
17 are arranged at the intervals in the vertical direction toward the bottom plate
2 when viewed from the top of the outdoor unit, and the plurality of heat radiation
fins 16 are arranged in parallel to the flow of the air on the electric component
partition plate 15. However, in Embodiment 2, the cooling efficiency of the heat sink
17 is further improved by adding a certain configuration to the configuration in Embodiment
1.
[0022] In Embodiment 2, a wind direction guide 18 molded using a material such as resin
is srcewed and fixed to the heat sink 17 of the outdoor unit 1 of the air conditioner
configured in the same manner as in Embodiment 1 with screws or the like so as to
cover the plurality of heat radiation fins 16.
As shown in Fig. 9 and Fig. 10, with the wind direction guide 18, a horn-shaped inlet
member 19 having a port widening toward the heat exchanger and a lid portion 20 covering
a section of the inlet member 19 from an end on the side of the heat sink 17 to the
outlet port of the heat sink 17 while keeping a constant space with respect to the
heat radiation fins 16 are integrally formed.
The inlet member 19 is attached at a certain angle β of inclination with respect to
one side portion of the heat radiation fins 16 in the longitudinal direction when
viewed from the top of the outdoor unit, and the surface area of the opening of the
inlet member 19 on the side of the heat exchanger is larger than the surface area
of the opening of the heat sink 17 on the side of the inlet port.
[0023] As described above, since the wind direction guide 18 is provided with the horn-shaped
inlet member 19 having the port widening toward the heat exchanger 5 on the side of
the inlet port of the heat sink 17, a configuration in Embodiment 2 has advantages
such that the flow rate of the air flowing into the heat sink 17 is increased, the
flow speed of the air passing through the heat radiation fins 16 can be increased,
and the cooling efficiency of the heat sink 17 can be enhanced.
In addition, since the section of the inlet member 19 from the end on the side of
the inlet port of the heat sink 17 to the end on the side of the outlet port of the
heat sink 17 is covered with the lid portion 20, the air flowing inward from the inlet
port of the heat sink 17 is prevented from leaving and escaping from the heat radiation
fins 16 at some midpoint of the heat sink 17 as shown by an arrow of a solid line
in Fig. 9, and reaches the outlet port of the heat sink 17.
[0024] Accordingly, since the heat exchange can be performed using the entire heat radiation
fins 16 effectively, the cooling efficiency of the heat sink 17 is enhanced. Granted
that the lid portion 20 is not provided, with the provision of the inlet member 19
on the side of the inlet port of the heat sink 17, the air is curved at some midpoint
of the heat sink 17, leaves the heat radiation fins 16 as indicated by an arrow of
a broken line in Fig. 9, and cannot reach the outlet port of the heat sink 17. Therefore,
the cooling efficiency of the heat sink 17 is lowered in comparison with the case
where the lid portion 20 is provided.
[0025] Since the wind direction guide 18 may be molded using synthetic resin or the like,
the shape can be changed freely to some extent. Therefore, when further enhancement
of the cooling efficiency of the heat sink 17 is wanted, the angle β of attachment
of the inlet member 19 of the wind direction guide 18 may be increased so that the
surface area of the opening is increased in order to increase the volume of the air
flowing into the inlet port of the heat sink 17.
Also, by molding the wind direction guide 18 with resin, molding of the wind direction
guide 18 having a relatively light weight at a relatively low cost is enabled. Therefore,
the reduction of the manufacturing cost and the weight is achieved.
Reference Sign List
[0026] 1: outdoor unit of air conditioner, 2: bottom plate, 3: partition plate, 4: compressor,
5: heat exchanger, 6: propeller fan, 7: fan motor, 8: front plate, 9: blowout port,
10: bell mouth, 11: hub, 12: front edge of a vane, 13: electronic substrate, 14: electric
component box, 15: electric component partition plate, 16: heat radiation fin, 17:
heat sink, 18: wind direction guide, 19: inlet member, 20: lid portion