FORM 2
THE PATENTS ACT, 1970
(39 of& 1970) THE PATENTS RULES, 2003 COMPLETE SPECIFICATION
[See section 10, Rule 13]
OUTDOOR UNIT;
MITSUBISHI ELECTRIC CORPORATION, A CORPORATION ORGANISED
AND EXISTING UNDER THE LAWS OF JAPAN, WHOSE ADDRESS IS 7-3,
MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO 1008310, JAPAN
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE
INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.
2
DESCRIPTION
Field
[0001] The present invention relates to an outdoor unit
5 of an air conditioner.
Background
[0002] In a housing constituting the outer casing of an
outdoor unit, a blower that generates an airflow and a
10 compressor that compresses refrigerant are provided. In
the housing, a partition plate is provided to partition the
interior into a blower chamber in which the blower is
placed and a compressor chamber in which the compressor is
placed. On the substrate on which an electric component
15 that drives the compressor is mounted, a heat dissipator is
provided to dissipate heat generated by the electric
component when this electric component drives the
compressor in order to reduce operation failures of the
electric component due to the influence of heat.
20 [0003] A heat sink serving as the heat dissipator
includes a base that receives heat generated by the
electric component, and a plurality of fins provided on the
base and spaced apart from each other. The heat sink is
provided in such a manner that the fins protrude toward the
25 blower chamber. Due to this configuration, the heat sink
dissipates heat through heat exchange between heat
dissipation surfaces of the fins and an airflow flowing
through the blower chamber. Patent Literature 1 discloses
an outdoor unit provided with a heat sink in an opening in
30 a partition plate such that it is possible to dissipate
heat of electric components constituting a power-supply
stabilizer circuit. In the outdoor unit disclosed in
Patent Literature 1, the electric components are mounted on
3
a substrate vertically placed. A plurality of fins are
provided on the vertical plane of a rectangular base and
extend in the horizontal direction. In the heat sink, the
fins having a length equal to the longer side of the base
5 are placed parallel to the longer side. Alternatively, in
the heat sink, the fins having a length greater than the
longer side of the base are placed to be angled relative to
the longer side.
10 Citation List
Patent Literature
[0004] Patent Literature 1: Japanese Patent Application
Laid-open No. H11-63573
15 Summary
Technical Problem
[0005] In an outdoor unit, electric components may be
mounted on a substrate horizontally placed, instead of the
substrate vertically placed. In the outdoor unit in which
20 electric components are mounted on the substrate
horizontally placed, a plurality of fins of a heat sink are
provided on a base horizontally placed in the same manner
as the substrate and extend in the vertical direction.
Along with an airflow, foreign matters such as dust or sand
25 possibly may enter the housing. Accordingly, the fins
provided to extend in the vertical direction make it
possible to reduce the accumulation amount of foreign
matters on the heat dissipation surfaces of the fins as
compared to the case where the fins are provided to extend
30 in the horizontal direction. Due to this configuration,
the outdoor unit, in which the electric components are
mounted on the substrate horizontally placed, can reduce a
reduction in heat dissipation efficiency caused by the
4
accumulation of foreign matters on the fins.
[0006] When the heat sink according to the conventional
technique described above is provided in an outdoor unit in
which electric components are mounted on a substrate
5 horizontally placed, the orientation of the fins is
significantly different from the direction of airflow
entering the heat sink and this may reduce the amount of
airflow passing through the space between the fins. Thus,
in the conventional technique, there is a problem in that
10 an insufficient amount of airflow passing through the space
between the fins may reduce the heat dissipation efficiency
of the electric components.
[0007] The present invention has been made in view of
the above problems, and an object of the present invention
15 is to provide an outdoor unit that can achieve improvement
in heat dissipation efficiency for heat generated by an
electric component provided in a housing.
Solution to Problem
20 [0008] To solve the above problems and to achieve the
object, an outdoor unit according to an aspect of the
present invention includes: a housing having a front
surface formed with an outlet and a back surface facing the
front surface, an airflow flowing through the outlet; a
25 substrate horizontally placed in the housing, an electric
component being mounted on the substrate; and a heat
dissipator comprising a plurality of fins, each of the fins
having a heat dissipation surface, the heat dissipator
dissipating, due to the airflow, heat generated by the
30 electric component. The heat dissipation surface of each
of the fins is parallel to the back surface or is angled at
greater than 0 degrees and less than 90 degrees relative to
the back surface in top view.
5
Advantageous Effects of Invention
[0009] The outdoor unit according to the present
invention has an effect where it is possible to achieve
5 improvement in heat dissipation efficiency for heat
generated by an electric component provided in a housing.
Brief Description of Drawings
[0010] FIG. 1 is a diagram illustrating a configuration
10 of an outdoor unit according to a first embodiment of the
present invention.
FIG. 2 is a front view of the outdoor unit illustrated
in FIG. 1.
FIG. 3 is a first diagram illustrating a heat
15 dissipator and electric components mounted on a substrate
in an internal configuration of the outdoor unit
illustrated in FIG. 1.
FIG. 4 is an explanatory diagram of a direction of
airflow in a housing of the outdoor unit illustrated in
20 FIG. 1.
FIG. 5 is an explanatory diagram of a relation between
the velocity of airflow passing through a space between
fins, and an angle formed between a heat dissipation
surface and a direction of airflow that reaches the heat
25 dissipator in the outdoor unit illustrated in FIG. 1.
FIG. 6 is a second diagram illustrating the heat
dissipator and the electric components mounted on the
substrate in the internal configuration of the outdoor unit
illustrated in FIG. 1.
30 FIG. 7 is a diagram illustrating a configuration of an
outdoor unit according to a second embodiment of the
present invention.
FIG. 8 is a diagram illustrating a configuration of
6
relevant parts of an outdoor unit according to a third
embodiment of the present invention.
Description of Embodiments
5 [0011] An outdoor unit according to embodiments of the
present invention will be described in detail below with
reference to the accompanying drawings. The present
invention is not limited to the embodiments.
[0012] First embodiment.
10 FIG. 1 is a diagram illustrating a configuration of an
outdoor unit 100 according to a first embodiment of the
present invention. FIG. 2 is a front view of the outdoor
unit 100 illustrated in FIG. 1. The outdoor unit 100 is an
outdoor unit intended for an air conditioner and is placed
15 outdoors. The air conditioner uses refrigerant circulating
between the outdoor unit 100 and an indoor unit placed
indoors to transfer heat between indoor air and outdoor air
in order to perform air conditioning in a room. FIG. 1
schematically illustrates an internal configuration of the
20 outdoor unit 100 when the outdoor unit 100 is viewed from
the top.
[0013] The outdoor unit 100 includes a housing 1
constituting the outer casing of the outdoor unit 100. The
housing 1 is a box member having six surfaces including a
25 front surface 2 formed with an outlet 8 through which an
airflow flows, a back surface 3 facing the front surface 2,
two side surfaces 4 and 5, a bottom surface 6, and a top
surface 7. In the first embodiment, a direction in which
the outlet 8 is directed is sometimes referred to as
30 "front" in the outdoor unit 100, while a direction opposite
to the front is sometimes referred to as "rear" in the
outdoor unit 100. The front and the rear are sometimes
referred collectively to as "front-rear direction". The
7
leftward direction and the rightward direction when the
outdoor unit 100 is viewed from the front are sometimes
referred to as "right-left direction". The side surface 4
is the left-side surface when the outdoor unit 100 is
5 viewed from the front. The side surface 5 is the rightside
surface when the outdoor unit 100 is viewed from the
front.
[0014] The outdoor unit 100 includes a blower 9 provided
in the housing 1 to move air drawn from outside of the
10 housing 1 to the outlet 8. The blower 9 is positioned at
the rear of the outlet 8. The blower 9 includes an
impeller 13 and a fan motor 14 that is a power source of
the impeller 13. The impeller 13 rotates by driving of the
fan motor 14 and generates an airflow.
15 [0015] The outdoor unit 100 includes a compressor 10 and
a heat exchanger 11 that are provided in the housing 1.
The compressor 10 compresses refrigerant. The compressor
10 is placed rightward of the outlet 8 and the blower 9,
that is, at a position closer to the side surface 5 than
20 the outlet 8 and the blower 9. The heat exchanger 11
exchanges heat between refrigerant and air. The heat
exchanger 11 is provided along the back surface 3 and the
side surface 4. A partition plate 12 is provided on the
bottom surface 6 in the housing 1. The partition plate 12
25 partitions the interior of the housing 1 into a blower
chamber 15 in which the blower 9 and the heat exchanger 11
are accommodated, and a compressor chamber 16 in which the
compressor 10 is accommodated. The partition plate 12
illustrated in FIG. 1 has a shape formed of a combination
30 of flat surfaces. The compressor chamber 16 is positioned
rightward of the blower 9. It is allowable that the
partition plate 12 has a shape including a curved surface.
In the internal configuration illustrated in FIG. 1, the
8
periphery around the compressor 10 is surrounded by the
housing 1 and the partition plate 12.
[0016] The outdoor unit 100 includes a substrate 17
having electric components mounted thereon, and a heat
5 dissipator 18 that dissipates heat generated by the
electric component. The substrate 17 is provided
substantially horizontally in the outdoor unit 100. On the
substrate 17, an electric component that drives the
compressor 10 and an electric component that drives the
10 blower 9 are mounted. The substrate 17 and the electric
components are accommodated in an electric component box
20. The electric component box 20 is placed rightward of a
rear end 29 of a bell mouth 19. The partition plate 12
partitions the interior of the housing 1 into the blower
15 chamber 15 and the compressor chamber 16 between the bottom
surface 6 and the top surface 7 at the rear of the electric
component box 20. The partition plate 12 partitions the
interior of the housing 1 into the blower chamber 15 and
the compressor chamber 16 between the bottom surface 6 and
20 the electric component box 20 under the electric component
box 20. The compressor 10 is placed at a position below
the electric component box 20 in the compressor chamber 16.
FIGS. 1 and 2 omit illustrations of the electric
components. FIG. 1 omits illustrations of the electric
25 component box 20.
[0017] As illustrated in FIG. 2, the outlet 8 has a
round shape in the front surface 2. The bell mouth 19 is
provided such that it protrudes from the peripheral edge of
the outlet 8 into the interior of the housing 1. The rear
30 end 29 of the bell mouth 19 is an end portion of the bell
mouth 19 protruding into the interior of the housing 1.
The rear end 29 is an end of the bell mouth 19 opposite to
the outlet 8. The back surface 3 and the side surface 4
9
are each provided with an opening through which outside air
is drawn into the housing 1. Air is drawn into the housing
1 through the openings in the back surface 3 and the side
surface 4 from outside of the housing 1, then undergoes
5 heat exchange in the heat exchanger 11, and then flows
toward the outlet 8. The partition plate 12 is provided
such that the blower chamber 15 is extended to the rear of
the electric component box 20. Accordingly, the outdoor
unit 100 can move an airflow, having passed through the
10 heat exchanger 11 at the rear of the electric component box
20, toward the outlet 8. FIGS. 1 and 2 omit illustrations
of the openings provided in the back surface 3 and the side
surface 4.
[0018] The heat dissipator 18 is a heat sink including a
15 plurality of fins 22. The heat dissipator 18 is attached
to the part of the bottom surface of the electric component
box 20 located leftward of the partition plate 12. The
heat dissipator 18 is provided below the substrate 17. As
illustrated in FIG. 1, the heat dissipator 18 is placed
20 rearward of the rear end 29 of the bell mouth 19, that is,
at a position closer to the back surface 3 than the rear
end 29 of the bell mouth 19. As illustrated in FIG. 2, the
heat dissipator 18 is placed above the bell mouth 19.
Further, as illustrated in FIGS. 1 and 2, the heat
25 dissipator 18 is placed rightward of the rear end 29 of the
bell mouth 19, that is, at a position closer to the
compressor 10 than the rear end 29 of the bell mouth 19.
FIG. 2 illustrates the compressor 10, the partition plate
12, the substrate 17, the heat dissipator 18, and the
30 electric component box 20 of the constituent elements
provided in the housing 1 by the dotted lines.
[0019] The heat dissipator 18 includes a base 21 that
receives heat generated by the electric components, and the
10
fins 22 arrayed to be spaced apart from each other. The
fins 22 serving as a heat dissipation plate are provided on
the horizontally placed base 21 and extend downward. FIG.
2 illustrates one of the fins 22 arrayed in the front-rear
5 direction.
[0020] FIG. 3 is a first diagram illustrating the heat
dissipator 18 and the electric components mounted on the
substrate 17 in the internal configuration of the outdoor
unit 100 illustrated in FIG. 1. FIG. 3 illustrates the
10 heat dissipator 18, a plurality of electric components that
are a first electric component 25 and a second electric
component 26, and the substrate 17 in an exploded manner.
The first electric component 25 and the second electric
component 26 are heating elements that require heat
15 dissipation. A bottom surface portion that is a part of
the electric component box 20 forming the bottom surface is
interposed between the first electric component 25 and the
base 21 and between the second electric component 26 and
the base 21. FIG. 3 omits illustrations of the bottom
20 surface portion of the electric component box 20.
[0021] The base 21 is a plate member having a flat
surface 24 with a rectangular shape. The longer side of
the rectangular shape of the flat surface 24 is a straight
line extending in the front-rear direction. The fin 22 is
25 a plate member provided vertically on the flat surface 24
of the base 21. A heat dissipation surface 23 is the main
flat surface for transferring heat to the air among the
heat dissipation surfaces constituting the fin 22. The
main flat surface for transferring heat to the air is
30 defined as a surface other than the surface with the
smallest area among the surfaces of the fin 22. For
example, the main flat surface is defined as a surface with
the largest area among the surfaces of the fin 22. In the
11
fin 22 with a plate-like shape, the main flat surface for
transferring heat to the air is defined as two flat
surfaces of the plate that are positioned opposed to, or
opposite, each other and that have the largest area among
5 the surfaces of the fin 22. The fins 22 are arrayed such
that the heat dissipation surfaces 23 of adjacent fins 22
face each other. Each space between the fins 22 serves as
a flow path through which an airflow having received heat
from the electric components passes. As a larger amount of
10 airflow passes through the space between the fins 22 and
receives heat from the electric components, the outdoor
unit 100 can dissipate heat of the electric components more
efficiently.
[0022] The heat dissipation surface 23 has a rectangular
15 shape with its longer side having a length equal to the
shorter side of the flat surface 24 of the base 21. In the
following descriptions, the longer-side direction of the
heat dissipation surface 23 is sometimes referred to as
"longitudinal direction of the fin 22". The longitudinal
20 direction of each of the fins 22 is parallel to the shorter
side of the flat surface 24 of the base 21, and is the
right-left direction. The heat dissipation surfaces 23 of
the fins 22 provided in the heat dissipator 18 are parallel
to the back surface 3 of the housing 1.
25 [0023] The first electric component 25 and the second
electric component 26 generate a larger amount of heat than
other electric components mounted on the substrate 17. The
first electric component 25 is a constituent component of
an inverter circuit that converts DC power to AC power to
30 drive the compressor 10. The second electric component 26
is a constituent component of a converter circuit that
converts AC power to DC power. Each of the first electric
component 25 and the second electric component 26 is either
12
a semiconductor element or a reactor. The first electric
component 25 and the second electric component 26 are
placed in such a manner as to be accommodated within the
area of the flat surface 24 of the base 21 in the front5
rear direction and the right-left direction. It is
allowable that the first electric component 25 and the
second electric component 26 are placed such that a part of
the first electric component 25 or a part of the second
electric component 26 extends over the area of the flat
10 surface 24 of the base 21.
[0024] It is allowable to use a wide-bandgap
semiconductor such as silicon carbide, gallium nitride,
gallium oxide, or diamond in the first electric component
25 and the second electric component 26. In general, a
15 wide-bandgap semiconductor generates a smaller amount of
heat than other types of semiconductors. Thus, by using a
wide-bandgap semiconductor, the outdoor unit 100 can
prevent the first electric component 25 and the second
electric component 26 from generating excessive heat.
20 [0025] Heat generated by the first electric component 25
and the second electric component 26 is transferred to the
base 21. The heat dissipator 18 transmits the heat having
been transferred to the base 21 to the air from the heat
dissipation surface 23 of each of the fins 22. It is
25 allowable that an insulating material is interposed between
the first electric component 25 and the base 21 and between
the second electric component 26 and the base 21.
[0026] Along with an airflow, foreign matters such as
dust or sand possibly enter the housing 1. In the first
30 embodiment, the substrate 17 is horizontally placed, and
thus the fins 22 are provided on the base 21 horizontally
placed in the same manner as the substrate 17 such that
they extend in the vertical direction. In the outdoor unit
13
100, the heat dissipation surface 23 of each of the fins 22
is a vertical plane, and this can reduce the accumulation
amount of foreign matters on the heat dissipation surface
23 as compared to the case where the heat dissipation
5 surface 23 is a horizontal plane. Due to this
configuration, the electric components are mounted on the
horizontally placed substrate 17, so that the outdoor unit
100 can reduce a reduction in heat dissipation efficiency
caused by the accumulation of foreign matters on the fins
10 22. The outdoor unit 100 is suitable for use in a dusty or
sandy environment.
[0027] Assuming that the substrate 17 is vertically
placed, the outdoor unit 100 needs to secure a space for
avoiding the fins 22 extending in the horizontal direction
15 from interfering with the bell mouth 19 or the blower 9.
The outdoor unit 100, in which the substrate 17 is
horizontally placed and thus the fins 22 extend in the
vertically direction, does not need to secure a space in
the right-left direction from the substrate 17. In the
20 outdoor unit 100, the substrate 17 is horizontally placed,
so that the substrate 17 and the electric components can be
placed in a space provided above the compressor 10.
Accordingly, the substrate 17 and the electric components
can be placed with less limitations. Due to this
25 placement, the outdoor unit 100 can achieve an internal
configuration suitable for downsizing. For this reason, it
is suitable to employ the configuration of the outdoor unit
100 in smaller-sized models. It is also allowable to
employ the configuration of the outdoor unit 100 in larger30
sized models.
[0028] Next, the relation between the direction of
airflow and the orientation of the fins 22 in the heat
dissipator 18 is described. FIG. 4 is an explanatory
14
diagram of the direction of airflow in the housing 1 of the
outdoor unit 100 illustrated in FIG. 1. FIG. 4 omits
illustrations of some of the constituent elements
illustrated in FIG. 1. In the substrate 17 and the heat
5 dissipator 18 illustrated in FIG. 1, each of the fins 22 is
illustrated by the solid line, while the substrate 17 and
the base 21 are illustrated by the dotted lines. The
arrows illustrated in FIG. 4 show the directions of
airflow.
10 [0029] An airflow is drawn into the housing 1 from the
openings in the back surface 3 and the side surface 4 by
rotation of the impeller 13, then passes through the heat
exchanger 11 illustrated in FIG. 1, and moves toward the
outlet 8. Since the impeller 13 and the outlet 8 are
15 placed leftward of the substrate 17, the airflow having
passed through the heat exchanger 11 at the rear of the
substrate 17 moves in a diagonally forward left direction.
The heat dissipator 18 is placed at a position rearward of
the rear end 29 of the bell mouth 19 and at a position
20 above and rightward of the bell mouth 19. Accordingly, the
airflow moving in a diagonally forward left direction
reaches the heat dissipator 18.
[0030] An angle α illustrated in FIG. 4 represents an
angle of the direction of airflow that reaches the right25
side end of the heat dissipator 18 relative to the back
surface 3. The angle α is defined as an angle in top view.
The case where the angle α is 0 degrees indicates that the
direction of airflow is parallel to the back surface 3,
which is the right-left direction. The case where the
30 angle α is 90 degrees indicates that the direction of
airflow is vertical to the back surface 3, which is the
front-rear direction. In a case where the angle α is
greater than 0 degrees and less than 90 degrees, the
15
direction of airflow is angled in a diagonally forward left
direction. As described above, an airflow moving in a
diagonally forward left direction reaches the heat
dissipator 18. Accordingly, the angle α is greater than 0
5 degrees and less than 90 degrees. Further, in the outdoor
unit 100 according to the first embodiment, the heat
dissipator 18 is placed at a position where the right-left
direction component of the airflow that reaches the rightside
end of the heat dissipator 18 is greater than the
10 front-rear direction component thereof. The angle α is
greater than 0 degrees and less than 45 degrees. Due to
rotation of the impeller 13, airflows reach the heat
dissipator 18 from various directions. The angle α
represents an average direction of the airflows that reach
15 the right-side end of the heat dissipator 18.
[0031] In the first embodiment, since the heat
dissipation surface 23 is parallel to the back surface 3,
an angle θ formed between the heat dissipation surface 23
and the direction of airflow that reaches the right-side
20 end of the heat dissipator 18 is equal to the angle α. As
described above, as the angle α is greater than 0 degrees
and less than 45 degrees, the angle θ is also greater than
0 degrees and less than 45 degrees.
[0032] FIG. 5 is an explanatory diagram of the relation
25 between the velocity of airflow passing through the space
between the fins 22, and the angle θ formed between the
heat dissipation surface 23 and the direction of airflow
that reaches the heat dissipator 18 in the outdoor unit 100
illustrated in FIG. 1. FIG. 5 illustrates a graph in which
30 the horizontal axis represents the angle θ, while the
vertical axis represents cos θ. In the following
descriptions, the direction of airflow that reaches the
heat dissipator 18 is assumed to be constant, and the
16
velocity of airflow passing through the space between the
fins 22 is assumed to be proportional to cos θ. As the
angle θ becomes closer to 0 degrees, the velocity of
airflow becomes faster. As the angle θ becomes closer to
5 90 degrees, the velocity of airflow becomes slower.
[0033] In FIG. 5, when the angle θ is equal to or
greater than 0 degrees and less than 45 degrees, cos θ
decreases more moderately relative to an increase in the
angle θ than the case where the angle θ is equal to or
10 greater than 45 degrees and equal to or less than 90
degrees. The angle θ is set to be less than 45 degrees and
thereby the outdoor unit 100 can reduce a reduction in the
velocity of airflow passing through the space between the
fins 22, and is capable of dissipating heat of the electric
15 components efficiently.
[0034] Assuming that the longitudinal direction of the
fins 22 corresponds to the front-rear direction that is
parallel to the longer side of the rectangular shape of the
base 21, the heat dissipation surface 23 of each of the
20 fins 22 is vertical to the back surface 3. In this case,
the angle θ formed between the heat dissipation surface 23
and the direction of airflow, that is the angle α, is
greater than 45 degrees. Accordingly, a larger amount of
airflow hits the heat dissipation surface 23 than the case
25 where the heat dissipation surface 23 of each of the fins
22 is parallel to the back surface 3. As a larger amount
of airflow hits the heat dissipation surfaces 23, a smaller
amount of airflow passes through the space between the fins
22 along each of the heat dissipation surfaces 23. This
30 makes it difficult to efficiently dissipate heat of the
electric components. The outdoor unit 100, in which the
heat dissipation surface 23 of each of the fins 22 is
parallel to the back surface 3, is capable of dissipating
17
heat of the electric components more efficiently than the
case where the heat dissipation surface 23 of each of the
fins 22 is vertical to the back surface 3.
[0035] In an airflow that reaches the heat dissipator
5 18, a component in a direction parallel to the back surface
3 is greater than a component in a direction vertical to
the back surface 3. Accordingly, in a case where the heat
dissipation surface 23 is parallel to the back surface 3,
the amount of airflow that flows away from the flow path
10 that is the space between the fins 22 and then flows toward
the outlet 8 is reduced as compared to the case where the
heat dissipation surface 23 is vertical to the back surface
3. Because the amount of airflow that flows away from the
flow path of the heat dissipator 18 is reduced, the outdoor
15 unit 100 is capable of dissipating heat of the electric
components efficiently.
[0036] In the first embodiment, the longitudinal
direction of the fins 22 is parallel to the shorter side of
the rectangular shape of the base 21. Consequently, the
20 flow path of the heat dissipator 18 is shorter than that in
the case where the longitudinal direction of the fins 22 is
parallel to the longer side of the rectangular shape of the
base 21. The length of the flow path is smaller than the
length of the longer side of the base 21. As the flow path
25 of the heat dissipator 18 is shorter, the outdoor unit 100
can further reduce a reduction in the velocity of airflow
caused by friction between the heat dissipation surface 23
and the airflow.
[0037] In a case where the heat dissipation surface 23
30 of each of the fins 22 is vertical to the back surface 3,
the airflow moving toward the front along the heat
dissipation surface 23 hits the part of the inner surface
of the housing 1 located rightward of the bell mouth 19.
18
Consequently, stagnation of air with heat having been
transferred from the fins 22 is more likely to occur. The
heat dissipation surface 23 of each of the fins 22 is
parallel to the back surface 3, so that an airflow moves
5 leftward along the heat dissipation surface 23, then moves
toward the outlet 8, and is discharged to the outside of
the housing 1. The outdoor unit 100 facilitates discharge
of the air with heat having been transferred from the fins
22, and is thus capable of efficiently dissipating heat
10 through the heat dissipator 18. Further, in the outdoor
unit 100, the heat dissipator 18 is placed rearward of the
rear end 29 of the bell mouth 19. Accordingly, the outdoor
unit 100 can further reduce the amount of air stagnating on
the right side of the bell mouth 19, and thus can
15 efficiently move the airflow having passed through the heat
dissipator 18 toward the outlet 8. The outdoor unit 100 is
capable of efficiently dissipating heat through the heat
dissipator 18, and is thus suitable for use in a hightemperature
environment.
20 [0038] As described above, the outdoor unit 100 can
reduce a reduction in the velocity of airflow passing
through the space between the fins 22, and is thus capable
of reducing the adhesion of foreign matters flowing with
the airflow to the heat dissipation surface 23. The
25 outdoor unit 100 can reduce a reduction in heat dissipation
efficiency caused by the accumulation of foreign matters on
the fins 22. The outdoor unit 100 is capable of reducing
the amount of air stagnating in the housing 1, and can
thereby reduce the accumulation amount of foreign matters
30 flowing with the airflow in the housing 1. The outdoor
unit 100 is suitable for use in a dusty or sandy
environment.
[0039] It is allowable that the outdoor unit 100 is
19
configured to have the heat dissipator 18 placed above the
substrate 17, instead of the configuration described above
in which the heat dissipator 18 is placed below the
substrate 17. In a case where the heat dissipator 18 is
5 placed above the substrate 17, the fins 22 are provided on
the base 21 and extend upward. Even when the heat
dissipator 18 is placed above the substrate 17, an airflow
flows in the same manner as the above case. Accordingly,
the outdoor unit 100 can efficiently dissipate heat of the
10 electric components and can reduce the accumulation amount
of foreign matters.
[0040] FIG. 6 is a second diagram illustrating the heat
dissipator 18 and the electric components mounted on the
substrate 17 in the internal configuration of the outdoor
15 unit 100 illustrated in FIG. 1. FIG. 6 illustrates the
heat dissipator 18 and the electric components mounted on
the substrate 17 when viewed from the top. FIG. 6
illustrates the substrate 17 and the fins 22 by the dotted
lines.
20 [0041] A third electric component 27 is one of the
electric components mounted on the substrate 17 and is
other than the first electric component 25 and the second
electric component 26. The third electric component 27 is
a constituent component of an inverter circuit that
25 converts DC power to AC power to drive the fan motor 14.
The third electric component 27 is either a semiconductor
element or a reactor. It is allowable that on the
substrate 17, an electric component other than the first
electric component 25, the second electric component 26,
30 and the third electric component 27 is mounted.
[0042] FIG. 6 illustrates the direction in which the
first electric component 25 and the second electric
component 26 are arrayed by a center line 28. The center
20
line 28 is a straight line connecting the center position
of the first electric component 25 in the right-left
direction and the center position of the second electric
component 26 in the right-left direction. The center line
5 28 extends in the front-rear direction and is vertical to
the heat dissipation surface 23. The direction in which
the first electric component 25 and the second electric
component 26 are arrayed is vertical to the heat
dissipation surface 23. The angle of 90 degrees is formed
10 between the direction of airflow passing through the flow
path and the direction in which the first electric
component 25 and the second electric component 26 are
arrayed. An airflow in a direction vertical to the
direction in which the first electric component 25 and the
15 second electric component 26 are arrayed flows through the
heat dissipator 18. An airflow that receives heat from the
first electric component 25 and an airflow that receives
heat from the second electric component 26 pass through
different flow paths from each other in the heat dissipator
20 18.
[0043] Assuming that the center line 28 is parallel to
the direction of the heat dissipation surface 23, an
airflow that receives heat from the first electric
component 25 and an airflow that receives heat from the
25 second electric component 26 both pass through a common
flow path in the heat dissipator 18. In this case, the
airflow having received heat from the first electric
component 25 is used to dissipate heat of the second
electric component 26. This makes it difficult to
30 efficiently dissipate heat of the second electric component
26. According to the first embodiment, the outdoor unit
100 is capable of dissipating heat of both the first
electric component 25 and the second electric component 26
21
more efficiently than the case where the direction of the
center line 28 aligns with the direction of airflow.
[0044] According to the first embodiment, the outdoor
unit 100, in which the heat dissipation surfaces 23 of the
5 fins 22 are parallel to the back surface 3 of the housing
1, can reduce a reduction in the velocity of airflow
passing through the space between the fins 22. Due to this
configuration, the outdoor unit 100 has an effect where it
is possible to achieve improvement in heat dissipation
10 efficiency for heat generated by an electric component
provided in a housing 1.
[0045] Second embodiment.
FIG. 7 is a diagram illustrating a configuration of
the outdoor unit 100 according to a second embodiment of
15 the present invention. In contrast to the outdoor unit 100
according to the first embodiment in which the heat
dissipation surface 23 is parallel to the back surface 3, a
heat dissipation surface 32 in the outdoor unit 100
according to the second embodiment is angled at greater
20 than 0 degrees and less than 90 degrees relative to the
back surface 3 in top view. In the second embodiment,
constituent elements identical to those of the first
embodiment are denoted by like reference signs and
descriptions overlapping with those of the first embodiment
25 will be omitted. FIG. 7 omits illustrations of a part of
constituent elements identical to those illustrated in FIG.
1.
[0046] A heat dissipator 30 is a heat sink including a
plurality of fins 31. The heat dissipator 30 is placed at
30 the same position as the heat dissipator 18 according to
the first embodiment. The fin 31 is a plate member
provided vertically on the flat surface 24 of the base 21
similarly to the fin 22 illustrated in FIG. 3. The heat
22
dissipation surface 32 is the main flat surface for
transferring heat to the air among the heat dissipation
surfaces constituting the fin 31. The heat dissipation
surface 32 is defined as two flat surfaces of the plate
5 that are positioned opposed to, or opposite, each other and
that have the largest area among the surfaces of the fin
31. The fins 31 are arrayed such that the heat dissipation
surfaces 32 of adjacent fins 31 face each other. In the
substrate 17 and the heat dissipator 30 illustrated in FIG.
10 7, each of the fins 31 is illustrated by the solid line,
while the substrate 17 and the base 21 are illustrated by
the dotted lines.
[0047] The heat dissipation surface 32 has a rectangular
shape with its longer side having a length greater than the
15 shorter side of the rectangular shape of the flat surface
24 of the base 21. In the following descriptions, the
longer-side direction of the heat dissipation surface 32 is
sometimes referred to as "longitudinal direction of the fin
31". The longitudinal direction of each of the fins 31 is
20 angled relative to the shorter side of the flat surface 24
of the base 21, while being angled relative to the rightleft
direction. On the flat surface 24, the fins 31 are
provided in such a manner that the heat dissipation
surfaces 32 are angled relative to the shorter side of the
25 rectangular shape without crossing the shorter side. In
the second embodiment, the flow path of the heat dissipator
30 is shorter than that in the case where the longitudinal
direction of the fin 31 is parallel to the longer side of
the base 21. The length of the flow path is smaller than
30 the length of the longer side of the base 21. As the flow
path of the heat dissipator 30 is shorter, the outdoor unit
100 can further reduce a reduction in the velocity of
airflow caused by friction between the heat dissipation
23
surface 32 and the airflow.
[0048] The longitudinal direction of the fin 31 is
angled at an angle β relative to the shorter side of the
flat surface 24 of the base 21. The angle β is defined as
5 an angle in top view. The heat dissipation surfaces 32 of
the fins 31 provided in the heat dissipator 30 are angled
at the angle β relative to the back surface 3. A case
where the angle β is 0 degrees indicates that the heat
dissipation surfaces 32 are parallel to the back surface 3
10 similarly to the first embodiment. A case where the angle
β is 90 degrees indicates that the heat dissipation
surfaces 32 are vertical to the back surface 3 and parallel
to the front-rear direction. In a case where the angle β
is greater than 0 degrees and less than 90 degrees, the
15 left portions of the heat dissipation surfaces 32 are
inclined forward. Similarly to the heat dissipator 18
according to the first embodiment, the heat dissipator 30
is placed at a position where the right-left direction
component of the airflow that reaches the right-side end of
20 the heat dissipator 30 is greater than the front-rear
direction component thereof. The angle α is greater than 0
degrees and less than 45 degrees.
[0049] Next, the relation between the direction of
airflow and the orientation of the fins 31 in the heat
25 dissipator 30 is described. In the outdoor unit 100
according to the second embodiment, an airflow moving in a
direction at the angle α relative to the back surface 3
reaches the right-side end of the heat dissipator 30
similarly to the first embodiment. In the second
30 embodiment, the heat dissipation surface 32 is angled at
the angle β relative to the back surface 3. Accordingly,
the angle θ formed between the heat dissipation surface 32
and the direction of airflow that reaches the right-side
24
end of the heat dissipator 30 is equal to the difference
obtained by subtracting the angle β from the angle α. The
angle θ satisfies the relation expressed as "θ=α-β".
[0050] In a case where the angle β is equal to the angle
5 α, that is, when the angle θ is 0 degrees, the direction of
airflow that reaches the heat dissipator 30 is parallel to
the heat dissipation surface 32. As the direction of the
heat dissipation surface 32 is closer to the direction of
airflow, the heat dissipation efficiency in the heat
10 dissipator 30 improves. While the angle α is greater than
0 degrees and less than 45 degrees, the angle β is set
greater than 0 degrees and less than 90 degrees, so that
the variation range of the angle θ can be set less than 45
degrees at which it is possible to efficiently dissipate
15 heat of the electric components, similarly to the first
embodiment. Due to this setting, the outdoor unit 100 can
efficiently dissipate heat of the electric components.
[0051] In the second embodiment, the angle formed
between the center line 28 illustrated in FIG. 6 and the
20 heat dissipation surface 32 is greater than 0 degrees and
less than 90 degrees. The heat dissipation surface 32 is
angled relative to the direction in which the first
electric component 25 and the second electric component 26
are arrayed. The angle of greater than 0 degrees and less
25 than 90 degrees is formed between the direction of airflow
passing through the flow path and the direction in which
the first electric component 25 and the second electric
component 26 are arrayed. In the second embodiment, the
angle β is set such that an airflow passing below the first
30 electric component 25 and an airflow passing below the
second electric component 26 pass through different flow
paths from each other in the heat dissipator 30. Due to
this setting, the outdoor unit 100 is capable of
25
efficiently dissipating heat of both the first electric
component 25 and the second electric component 26.
[0052] When the angle β is greater than 0 degrees and
less than 45 degrees, the outdoor unit 100 can move an
5 airflow angled at the angle α that is greater than 0
degrees and less than 45 degrees efficiently through the
flow path of the heat dissipator 30. Due to this
configuration, the outdoor unit 100 can further efficiently
dissipate heat of the electric components.
10 [0053] In the second embodiment, the outdoor unit 100,
in which the heat dissipation surfaces 32 of the fins 31
are angled at greater than 0 degrees and less than 90
degrees relative to the back surface 3, can reduce a
reduction in the velocity of airflow passing through the
15 space between the fins 31. Due to this configuration, the
outdoor unit 100 can achieve the effect of improving the
efficiency in dissipating heat generated by the electric
components provided in the housing 1.
[0054] Third embodiment.
20 FIG. 8 is a diagram illustrating a configuration of
relevant parts of the outdoor unit 100 according to a third
embodiment of the present invention. The outdoor unit 100
according to the third embodiment includes an airflow
direction adjuster that adjusts the direction of airflow
25 toward the heat dissipator 18. In the third embodiment,
constituent elements identical to those of the first and
second embodiments are denoted by like reference signs and
descriptions overlapping with those of the first and second
embodiments will be omitted.
30 [0055] The outdoor unit 100 according to the third
embodiment is obtained by adding the airflow direction
adjuster to the outdoor unit 100 according to the first
embodiment. FIG. 8 illustrates the heat dissipator 18 and
26
the electric components mounted on the substrate 17 when
viewed from the top. FIG. 8 illustrates the substrate 17
and the fins 22 by the dotted lines. It is allowable that
the airflow direction adjuster according to the third
5 embodiment is provided in the outdoor unit 100 according to
the second embodiment.
[0056] Airflow direction adjusting plates 40 and 41
serving as the airflow direction adjuster are provided to
extend from the base 21 diagonally rearward and to the
10 right. The airflow direction adjusting plate 40 extends
diagonally rearward and to the right from the right-rear
corner of the base 21. The airflow direction adjusting
plate 41 extends diagonally rearward and to the right from
the right-front corner of the base 21. Constituent
15 elements such as cables or other components are placed
outside a region surrounded by the two airflow direction
adjusting plates 40 and 41 and the base 21. The
constituent elements that interfere with airflow movement
are placed outside the region, so that the outdoor unit 100
20 can efficiently move the airflow to the heat dissipator 18.
[0057] When an airflow moves from the heat exchanger 11
toward the space between the two airflow direction
adjusting plates 40 and 41, the direction of the airflow is
adjusted by the airflow direction adjusting plates 40 and
25 41, and then this airflow is collected at the heat
dissipator 18. The outdoor unit 100 allows a larger amount
of airflow to move to the heat dissipator 18, and thus can
dissipate heat of the electric components efficiently. The
positions and shapes of the airflow direction adjusting
30 plates 40 and 41 are not limited to those illustrated in
FIG. 8, and can be appropriately changed. It is allowable
that only one airflow direction adjusting plate is provided
to serve as the air direction adjuster, or more than two
27
airflow direction adjusting plates are provided to serve as
the air direction adjuster.
[0058] The configurations described in the above
embodiments are only examples of the content of the present
5 invention. The configurations can be combined with other
well-known techniques, and part of each of the
configurations can be omitted or modified without departing
from the scope of the present invention.
10 Reference Signs List
[0059] 1 housing, 2 front surface, 3 back surface, 4,
5 side surface, 6 bottom surface, 7 top surface, 8
outlet, 9 blower, 10 compressor, 11 heat exchanger, 12
partition plate, 13 impeller, 14 fan motor, 15 blower
15 chamber, 16 compressor chamber, 17 substrate, 18, 30
heat dissipator, 19 bell mouth, 20 electric component
box, 21 base, 22, 31 fin, 23, 32 heat dissipation
surface, 24 flat surface, 25 first electric component, 26
second electric component, 27 third electric component, 28
20 center line, 29 rear end, 40, 41 airflow direction
adjusting plate, 100 outdoor unit.
28
We Claim:
1. An outdoor unit comprising:
a housing having a front surface formed with an outlet
5 and a back surface facing the front surface, an airflow
flowing through the outlet;
a substrate horizontally placed in the housing, an
electric component being mounted on the substrate; and
a heat dissipator comprising a plurality of fins, each
10 of the fins having a heat dissipation surface, the heat
dissipator dissipating, due to the airflow, heat generated
by the electric component, wherein
the heat dissipation surface of each of the fins is
parallel to the back surface or is angled at greater than 0
15 degrees and less than 90 degrees relative to the back
surface in top view.
2. The outdoor unit according to claim 1, wherein
the heat dissipator includes a base having a
20 rectangular surface, the fins being provided on the base,
a flow path is formed between the fins, an airflow
passing through the flow path, and
a length of the flow path is smaller than a length of
a longer side of the base.
25
3. The outdoor unit according to claim 1 or 2, wherein
a plurality of the electric components are arrayed on
the substrate, the electric components being heating
elements, and
30 an angle is formed between a direction in which the
electric components are arrayed and a direction of airflow
passing through a flow path formed between the fins.
29
4. The outdoor unit according to any one of claims 1 to
3, comprising a bell mouth provided so as to protrude from
a peripheral edge of the outlet into an interior of the
housing, the bell mouth including an end portion protruding
5 into an interior of the housing, wherein
the heat dissipator is placed at a position closer to
the back surface than the end portion of the bell mouth.
5. The outdoor unit according to any one of claims 1 to
10 4, comprising an airflow direction adjuster adjusting a
direction of airflow toward the heat dissipator.
6. The outdoor unit according to any one of claims 1 to
5, wherein a wide-bandgap semiconductor is used for the
15 electric component.